2007-04-27 06:48:28 +08:00
|
|
|
======================
|
|
|
|
|
RxRPC NETWORK PROTOCOL
|
|
|
|
|
======================
|
|
|
|
|
|
|
|
|
|
The RxRPC protocol driver provides a reliable two-phase transport on top of UDP
|
|
|
|
|
that can be used to perform RxRPC remote operations. This is done over sockets
|
|
|
|
|
of AF_RXRPC family, using sendmsg() and recvmsg() with control data to send and
|
|
|
|
|
receive data, aborts and errors.
|
|
|
|
|
|
|
|
|
|
Contents of this document:
|
|
|
|
|
|
|
|
|
|
(*) Overview.
|
|
|
|
|
|
|
|
|
|
(*) RxRPC protocol summary.
|
|
|
|
|
|
|
|
|
|
(*) AF_RXRPC driver model.
|
|
|
|
|
|
|
|
|
|
(*) Control messages.
|
|
|
|
|
|
|
|
|
|
(*) Socket options.
|
|
|
|
|
|
|
|
|
|
(*) Security.
|
|
|
|
|
|
|
|
|
|
(*) Example client usage.
|
|
|
|
|
|
|
|
|
|
(*) Example server usage.
|
|
|
|
|
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
(*) AF_RXRPC kernel interface.
|
|
|
|
|
|
2014-02-08 02:58:44 +08:00
|
|
|
(*) Configurable parameters.
|
|
|
|
|
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
========
|
|
|
|
|
OVERVIEW
|
|
|
|
|
========
|
|
|
|
|
|
|
|
|
|
RxRPC is a two-layer protocol. There is a session layer which provides
|
|
|
|
|
reliable virtual connections using UDP over IPv4 (or IPv6) as the transport
|
|
|
|
|
layer, but implements a real network protocol; and there's the presentation
|
|
|
|
|
layer which renders structured data to binary blobs and back again using XDR
|
|
|
|
|
(as does SunRPC):
|
|
|
|
|
|
|
|
|
|
+-------------+
|
|
|
|
|
| Application |
|
|
|
|
|
+-------------+
|
|
|
|
|
| XDR | Presentation
|
|
|
|
|
+-------------+
|
|
|
|
|
| RxRPC | Session
|
|
|
|
|
+-------------+
|
|
|
|
|
| UDP | Transport
|
|
|
|
|
+-------------+
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
AF_RXRPC provides:
|
|
|
|
|
|
|
|
|
|
(1) Part of an RxRPC facility for both kernel and userspace applications by
|
|
|
|
|
making the session part of it a Linux network protocol (AF_RXRPC).
|
|
|
|
|
|
|
|
|
|
(2) A two-phase protocol. The client transmits a blob (the request) and then
|
|
|
|
|
receives a blob (the reply), and the server receives the request and then
|
|
|
|
|
transmits the reply.
|
|
|
|
|
|
|
|
|
|
(3) Retention of the reusable bits of the transport system set up for one call
|
|
|
|
|
to speed up subsequent calls.
|
|
|
|
|
|
|
|
|
|
(4) A secure protocol, using the Linux kernel's key retention facility to
|
|
|
|
|
manage security on the client end. The server end must of necessity be
|
|
|
|
|
more active in security negotiations.
|
|
|
|
|
|
|
|
|
|
AF_RXRPC does not provide XDR marshalling/presentation facilities. That is
|
|
|
|
|
left to the application. AF_RXRPC only deals in blobs. Even the operation ID
|
|
|
|
|
is just the first four bytes of the request blob, and as such is beyond the
|
|
|
|
|
kernel's interest.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sockets of AF_RXRPC family are:
|
|
|
|
|
|
|
|
|
|
(1) created as type SOCK_DGRAM;
|
|
|
|
|
|
|
|
|
|
(2) provided with a protocol of the type of underlying transport they're going
|
|
|
|
|
to use - currently only PF_INET is supported.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
The Andrew File System (AFS) is an example of an application that uses this and
|
|
|
|
|
that has both kernel (filesystem) and userspace (utility) components.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
======================
|
|
|
|
|
RXRPC PROTOCOL SUMMARY
|
|
|
|
|
======================
|
|
|
|
|
|
|
|
|
|
An overview of the RxRPC protocol:
|
|
|
|
|
|
|
|
|
|
(*) RxRPC sits on top of another networking protocol (UDP is the only option
|
|
|
|
|
currently), and uses this to provide network transport. UDP ports, for
|
|
|
|
|
example, provide transport endpoints.
|
|
|
|
|
|
|
|
|
|
(*) RxRPC supports multiple virtual "connections" from any given transport
|
|
|
|
|
endpoint, thus allowing the endpoints to be shared, even to the same
|
|
|
|
|
remote endpoint.
|
|
|
|
|
|
|
|
|
|
(*) Each connection goes to a particular "service". A connection may not go
|
|
|
|
|
to multiple services. A service may be considered the RxRPC equivalent of
|
|
|
|
|
a port number. AF_RXRPC permits multiple services to share an endpoint.
|
|
|
|
|
|
|
|
|
|
(*) Client-originating packets are marked, thus a transport endpoint can be
|
|
|
|
|
shared between client and server connections (connections have a
|
|
|
|
|
direction).
|
|
|
|
|
|
|
|
|
|
(*) Up to a billion connections may be supported concurrently between one
|
|
|
|
|
local transport endpoint and one service on one remote endpoint. An RxRPC
|
|
|
|
|
connection is described by seven numbers:
|
|
|
|
|
|
|
|
|
|
Local address }
|
|
|
|
|
Local port } Transport (UDP) address
|
|
|
|
|
Remote address }
|
|
|
|
|
Remote port }
|
|
|
|
|
Direction
|
|
|
|
|
Connection ID
|
|
|
|
|
Service ID
|
|
|
|
|
|
|
|
|
|
(*) Each RxRPC operation is a "call". A connection may make up to four
|
|
|
|
|
billion calls, but only up to four calls may be in progress on a
|
|
|
|
|
connection at any one time.
|
|
|
|
|
|
|
|
|
|
(*) Calls are two-phase and asymmetric: the client sends its request data,
|
|
|
|
|
which the service receives; then the service transmits the reply data
|
|
|
|
|
which the client receives.
|
|
|
|
|
|
|
|
|
|
(*) The data blobs are of indefinite size, the end of a phase is marked with a
|
|
|
|
|
flag in the packet. The number of packets of data making up one blob may
|
|
|
|
|
not exceed 4 billion, however, as this would cause the sequence number to
|
|
|
|
|
wrap.
|
|
|
|
|
|
|
|
|
|
(*) The first four bytes of the request data are the service operation ID.
|
|
|
|
|
|
|
|
|
|
(*) Security is negotiated on a per-connection basis. The connection is
|
|
|
|
|
initiated by the first data packet on it arriving. If security is
|
|
|
|
|
requested, the server then issues a "challenge" and then the client
|
|
|
|
|
replies with a "response". If the response is successful, the security is
|
|
|
|
|
set for the lifetime of that connection, and all subsequent calls made
|
|
|
|
|
upon it use that same security. In the event that the server lets a
|
|
|
|
|
connection lapse before the client, the security will be renegotiated if
|
|
|
|
|
the client uses the connection again.
|
|
|
|
|
|
|
|
|
|
(*) Calls use ACK packets to handle reliability. Data packets are also
|
|
|
|
|
explicitly sequenced per call.
|
|
|
|
|
|
2013-10-30 15:46:15 +08:00
|
|
|
(*) There are two types of positive acknowledgment: hard-ACKs and soft-ACKs.
|
2007-04-27 06:48:28 +08:00
|
|
|
A hard-ACK indicates to the far side that all the data received to a point
|
|
|
|
|
has been received and processed; a soft-ACK indicates that the data has
|
|
|
|
|
been received but may yet be discarded and re-requested. The sender may
|
|
|
|
|
not discard any transmittable packets until they've been hard-ACK'd.
|
|
|
|
|
|
|
|
|
|
(*) Reception of a reply data packet implicitly hard-ACK's all the data
|
|
|
|
|
packets that make up the request.
|
|
|
|
|
|
|
|
|
|
(*) An call is complete when the request has been sent, the reply has been
|
|
|
|
|
received and the final hard-ACK on the last packet of the reply has
|
|
|
|
|
reached the server.
|
|
|
|
|
|
|
|
|
|
(*) An call may be aborted by either end at any time up to its completion.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
=====================
|
|
|
|
|
AF_RXRPC DRIVER MODEL
|
|
|
|
|
=====================
|
|
|
|
|
|
|
|
|
|
About the AF_RXRPC driver:
|
|
|
|
|
|
|
|
|
|
(*) The AF_RXRPC protocol transparently uses internal sockets of the transport
|
|
|
|
|
protocol to represent transport endpoints.
|
|
|
|
|
|
|
|
|
|
(*) AF_RXRPC sockets map onto RxRPC connection bundles. Actual RxRPC
|
|
|
|
|
connections are handled transparently. One client socket may be used to
|
|
|
|
|
make multiple simultaneous calls to the same service. One server socket
|
|
|
|
|
may handle calls from many clients.
|
|
|
|
|
|
|
|
|
|
(*) Additional parallel client connections will be initiated to support extra
|
|
|
|
|
concurrent calls, up to a tunable limit.
|
|
|
|
|
|
|
|
|
|
(*) Each connection is retained for a certain amount of time [tunable] after
|
|
|
|
|
the last call currently using it has completed in case a new call is made
|
|
|
|
|
that could reuse it.
|
|
|
|
|
|
|
|
|
|
(*) Each internal UDP socket is retained [tunable] for a certain amount of
|
|
|
|
|
time [tunable] after the last connection using it discarded, in case a new
|
|
|
|
|
connection is made that could use it.
|
|
|
|
|
|
|
|
|
|
(*) A client-side connection is only shared between calls if they have have
|
|
|
|
|
the same key struct describing their security (and assuming the calls
|
|
|
|
|
would otherwise share the connection). Non-secured calls would also be
|
|
|
|
|
able to share connections with each other.
|
|
|
|
|
|
|
|
|
|
(*) A server-side connection is shared if the client says it is.
|
|
|
|
|
|
|
|
|
|
(*) ACK'ing is handled by the protocol driver automatically, including ping
|
|
|
|
|
replying.
|
|
|
|
|
|
|
|
|
|
(*) SO_KEEPALIVE automatically pings the other side to keep the connection
|
|
|
|
|
alive [TODO].
|
|
|
|
|
|
|
|
|
|
(*) If an ICMP error is received, all calls affected by that error will be
|
|
|
|
|
aborted with an appropriate network error passed through recvmsg().
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Interaction with the user of the RxRPC socket:
|
|
|
|
|
|
|
|
|
|
(*) A socket is made into a server socket by binding an address with a
|
|
|
|
|
non-zero service ID.
|
|
|
|
|
|
|
|
|
|
(*) In the client, sending a request is achieved with one or more sendmsgs,
|
|
|
|
|
followed by the reply being received with one or more recvmsgs.
|
|
|
|
|
|
|
|
|
|
(*) The first sendmsg for a request to be sent from a client contains a tag to
|
|
|
|
|
be used in all other sendmsgs or recvmsgs associated with that call. The
|
|
|
|
|
tag is carried in the control data.
|
|
|
|
|
|
|
|
|
|
(*) connect() is used to supply a default destination address for a client
|
|
|
|
|
socket. This may be overridden by supplying an alternate address to the
|
|
|
|
|
first sendmsg() of a call (struct msghdr::msg_name).
|
|
|
|
|
|
|
|
|
|
(*) If connect() is called on an unbound client, a random local port will
|
|
|
|
|
bound before the operation takes place.
|
|
|
|
|
|
|
|
|
|
(*) A server socket may also be used to make client calls. To do this, the
|
|
|
|
|
first sendmsg() of the call must specify the target address. The server's
|
|
|
|
|
transport endpoint is used to send the packets.
|
|
|
|
|
|
|
|
|
|
(*) Once the application has received the last message associated with a call,
|
|
|
|
|
the tag is guaranteed not to be seen again, and so it can be used to pin
|
|
|
|
|
client resources. A new call can then be initiated with the same tag
|
|
|
|
|
without fear of interference.
|
|
|
|
|
|
|
|
|
|
(*) In the server, a request is received with one or more recvmsgs, then the
|
|
|
|
|
the reply is transmitted with one or more sendmsgs, and then the final ACK
|
|
|
|
|
is received with a last recvmsg.
|
|
|
|
|
|
|
|
|
|
(*) When sending data for a call, sendmsg is given MSG_MORE if there's more
|
|
|
|
|
data to come on that call.
|
|
|
|
|
|
|
|
|
|
(*) When receiving data for a call, recvmsg flags MSG_MORE if there's more
|
|
|
|
|
data to come for that call.
|
|
|
|
|
|
|
|
|
|
(*) When receiving data or messages for a call, MSG_EOR is flagged by recvmsg
|
|
|
|
|
to indicate the terminal message for that call.
|
|
|
|
|
|
|
|
|
|
(*) A call may be aborted by adding an abort control message to the control
|
|
|
|
|
data. Issuing an abort terminates the kernel's use of that call's tag.
|
|
|
|
|
Any messages waiting in the receive queue for that call will be discarded.
|
|
|
|
|
|
|
|
|
|
(*) Aborts, busy notifications and challenge packets are delivered by recvmsg,
|
|
|
|
|
and control data messages will be set to indicate the context. Receiving
|
|
|
|
|
an abort or a busy message terminates the kernel's use of that call's tag.
|
|
|
|
|
|
|
|
|
|
(*) The control data part of the msghdr struct is used for a number of things:
|
|
|
|
|
|
|
|
|
|
(*) The tag of the intended or affected call.
|
|
|
|
|
|
|
|
|
|
(*) Sending or receiving errors, aborts and busy notifications.
|
|
|
|
|
|
|
|
|
|
(*) Notifications of incoming calls.
|
|
|
|
|
|
|
|
|
|
(*) Sending debug requests and receiving debug replies [TODO].
|
|
|
|
|
|
|
|
|
|
(*) When the kernel has received and set up an incoming call, it sends a
|
|
|
|
|
message to server application to let it know there's a new call awaiting
|
|
|
|
|
its acceptance [recvmsg reports a special control message]. The server
|
|
|
|
|
application then uses sendmsg to assign a tag to the new call. Once that
|
|
|
|
|
is done, the first part of the request data will be delivered by recvmsg.
|
|
|
|
|
|
|
|
|
|
(*) The server application has to provide the server socket with a keyring of
|
|
|
|
|
secret keys corresponding to the security types it permits. When a secure
|
|
|
|
|
connection is being set up, the kernel looks up the appropriate secret key
|
|
|
|
|
in the keyring and then sends a challenge packet to the client and
|
|
|
|
|
receives a response packet. The kernel then checks the authorisation of
|
|
|
|
|
the packet and either aborts the connection or sets up the security.
|
|
|
|
|
|
|
|
|
|
(*) The name of the key a client will use to secure its communications is
|
|
|
|
|
nominated by a socket option.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Notes on recvmsg:
|
|
|
|
|
|
|
|
|
|
(*) If there's a sequence of data messages belonging to a particular call on
|
|
|
|
|
the receive queue, then recvmsg will keep working through them until:
|
|
|
|
|
|
|
|
|
|
(a) it meets the end of that call's received data,
|
|
|
|
|
|
|
|
|
|
(b) it meets a non-data message,
|
|
|
|
|
|
|
|
|
|
(c) it meets a message belonging to a different call, or
|
|
|
|
|
|
|
|
|
|
(d) it fills the user buffer.
|
|
|
|
|
|
|
|
|
|
If recvmsg is called in blocking mode, it will keep sleeping, awaiting the
|
|
|
|
|
reception of further data, until one of the above four conditions is met.
|
|
|
|
|
|
|
|
|
|
(2) MSG_PEEK operates similarly, but will return immediately if it has put any
|
|
|
|
|
data in the buffer rather than sleeping until it can fill the buffer.
|
|
|
|
|
|
|
|
|
|
(3) If a data message is only partially consumed in filling a user buffer,
|
|
|
|
|
then the remainder of that message will be left on the front of the queue
|
|
|
|
|
for the next taker. MSG_TRUNC will never be flagged.
|
|
|
|
|
|
|
|
|
|
(4) If there is more data to be had on a call (it hasn't copied the last byte
|
|
|
|
|
of the last data message in that phase yet), then MSG_MORE will be
|
|
|
|
|
flagged.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
================
|
|
|
|
|
CONTROL MESSAGES
|
|
|
|
|
================
|
|
|
|
|
|
|
|
|
|
AF_RXRPC makes use of control messages in sendmsg() and recvmsg() to multiplex
|
|
|
|
|
calls, to invoke certain actions and to report certain conditions. These are:
|
|
|
|
|
|
|
|
|
|
MESSAGE ID SRT DATA MEANING
|
|
|
|
|
======================= === =========== ===============================
|
|
|
|
|
RXRPC_USER_CALL_ID sr- User ID App's call specifier
|
|
|
|
|
RXRPC_ABORT srt Abort code Abort code to issue/received
|
|
|
|
|
RXRPC_ACK -rt n/a Final ACK received
|
|
|
|
|
RXRPC_NET_ERROR -rt error num Network error on call
|
|
|
|
|
RXRPC_BUSY -rt n/a Call rejected (server busy)
|
|
|
|
|
RXRPC_LOCAL_ERROR -rt error num Local error encountered
|
|
|
|
|
RXRPC_NEW_CALL -r- n/a New call received
|
|
|
|
|
RXRPC_ACCEPT s-- n/a Accept new call
|
2017-06-05 21:30:49 +08:00
|
|
|
RXRPC_EXCLUSIVE_CALL s-- n/a Make an exclusive client call
|
|
|
|
|
RXRPC_UPGRADE_SERVICE s-- n/a Client call can be upgraded
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
(SRT = usable in Sendmsg / delivered by Recvmsg / Terminal message)
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_USER_CALL_ID
|
|
|
|
|
|
|
|
|
|
This is used to indicate the application's call ID. It's an unsigned long
|
|
|
|
|
that the app specifies in the client by attaching it to the first data
|
|
|
|
|
message or in the server by passing it in association with an RXRPC_ACCEPT
|
|
|
|
|
message. recvmsg() passes it in conjunction with all messages except
|
|
|
|
|
those of the RXRPC_NEW_CALL message.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_ABORT
|
|
|
|
|
|
|
|
|
|
This is can be used by an application to abort a call by passing it to
|
|
|
|
|
sendmsg, or it can be delivered by recvmsg to indicate a remote abort was
|
|
|
|
|
received. Either way, it must be associated with an RXRPC_USER_CALL_ID to
|
|
|
|
|
specify the call affected. If an abort is being sent, then error EBADSLT
|
|
|
|
|
will be returned if there is no call with that user ID.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_ACK
|
|
|
|
|
|
|
|
|
|
This is delivered to a server application to indicate that the final ACK
|
|
|
|
|
of a call was received from the client. It will be associated with an
|
|
|
|
|
RXRPC_USER_CALL_ID to indicate the call that's now complete.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_NET_ERROR
|
|
|
|
|
|
|
|
|
|
This is delivered to an application to indicate that an ICMP error message
|
|
|
|
|
was encountered in the process of trying to talk to the peer. An
|
|
|
|
|
errno-class integer value will be included in the control message data
|
|
|
|
|
indicating the problem, and an RXRPC_USER_CALL_ID will indicate the call
|
|
|
|
|
affected.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_BUSY
|
|
|
|
|
|
|
|
|
|
This is delivered to a client application to indicate that a call was
|
|
|
|
|
rejected by the server due to the server being busy. It will be
|
|
|
|
|
associated with an RXRPC_USER_CALL_ID to indicate the rejected call.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_LOCAL_ERROR
|
|
|
|
|
|
|
|
|
|
This is delivered to an application to indicate that a local error was
|
|
|
|
|
encountered and that a call has been aborted because of it. An
|
|
|
|
|
errno-class integer value will be included in the control message data
|
|
|
|
|
indicating the problem, and an RXRPC_USER_CALL_ID will indicate the call
|
|
|
|
|
affected.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_NEW_CALL
|
|
|
|
|
|
|
|
|
|
This is delivered to indicate to a server application that a new call has
|
|
|
|
|
arrived and is awaiting acceptance. No user ID is associated with this,
|
|
|
|
|
as a user ID must subsequently be assigned by doing an RXRPC_ACCEPT.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_ACCEPT
|
|
|
|
|
|
|
|
|
|
This is used by a server application to attempt to accept a call and
|
|
|
|
|
assign it a user ID. It should be associated with an RXRPC_USER_CALL_ID
|
|
|
|
|
to indicate the user ID to be assigned. If there is no call to be
|
|
|
|
|
accepted (it may have timed out, been aborted, etc.), then sendmsg will
|
|
|
|
|
return error ENODATA. If the user ID is already in use by another call,
|
|
|
|
|
then error EBADSLT will be returned.
|
|
|
|
|
|
2017-06-05 21:30:49 +08:00
|
|
|
(*) RXRPC_EXCLUSIVE_CALL
|
|
|
|
|
|
|
|
|
|
This is used to indicate that a client call should be made on a one-off
|
|
|
|
|
connection. The connection is discarded once the call has terminated.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_UPGRADE_SERVICE
|
|
|
|
|
|
|
|
|
|
This is used to make a client call to probe if the specified service ID
|
|
|
|
|
may be upgraded by the server. The caller must check msg_name returned to
|
|
|
|
|
recvmsg() for the service ID actually in use. The operation probed must
|
|
|
|
|
be one that takes the same arguments in both services.
|
|
|
|
|
|
|
|
|
|
Once this has been used to establish the upgrade capability (or lack
|
|
|
|
|
thereof) of the server, the service ID returned should be used for all
|
|
|
|
|
future communication to that server and RXRPC_UPGRADE_SERVICE should no
|
|
|
|
|
longer be set.
|
|
|
|
|
|
2017-06-07 23:27:15 +08:00
|
|
|
The symbol RXRPC__SUPPORTED is defined as one more than the highest control
|
|
|
|
|
message type supported. At run time this can be queried by means of the
|
|
|
|
|
RXRPC_SUPPORTED_CMSG socket option (see below).
|
|
|
|
|
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
==============
|
|
|
|
|
SOCKET OPTIONS
|
|
|
|
|
==============
|
|
|
|
|
|
|
|
|
|
AF_RXRPC sockets support a few socket options at the SOL_RXRPC level:
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_SECURITY_KEY
|
|
|
|
|
|
|
|
|
|
This is used to specify the description of the key to be used. The key is
|
|
|
|
|
extracted from the calling process's keyrings with request_key() and
|
|
|
|
|
should be of "rxrpc" type.
|
|
|
|
|
|
|
|
|
|
The optval pointer points to the description string, and optlen indicates
|
|
|
|
|
how long the string is, without the NUL terminator.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_SECURITY_KEYRING
|
|
|
|
|
|
|
|
|
|
Similar to above but specifies a keyring of server secret keys to use (key
|
|
|
|
|
type "keyring"). See the "Security" section.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_EXCLUSIVE_CONNECTION
|
|
|
|
|
|
|
|
|
|
This is used to request that new connections should be used for each call
|
|
|
|
|
made subsequently on this socket. optval should be NULL and optlen 0.
|
|
|
|
|
|
|
|
|
|
(*) RXRPC_MIN_SECURITY_LEVEL
|
|
|
|
|
|
|
|
|
|
This is used to specify the minimum security level required for calls on
|
|
|
|
|
this socket. optval must point to an int containing one of the following
|
|
|
|
|
values:
|
|
|
|
|
|
|
|
|
|
(a) RXRPC_SECURITY_PLAIN
|
|
|
|
|
|
|
|
|
|
Encrypted checksum only.
|
|
|
|
|
|
|
|
|
|
(b) RXRPC_SECURITY_AUTH
|
|
|
|
|
|
|
|
|
|
Encrypted checksum plus packet padded and first eight bytes of packet
|
|
|
|
|
encrypted - which includes the actual packet length.
|
|
|
|
|
|
|
|
|
|
(c) RXRPC_SECURITY_ENCRYPTED
|
|
|
|
|
|
|
|
|
|
Encrypted checksum plus entire packet padded and encrypted, including
|
|
|
|
|
actual packet length.
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(*) RXRPC_UPGRADEABLE_SERVICE
|
|
|
|
|
|
|
|
|
|
This is used to indicate that a service socket with two bindings may
|
|
|
|
|
upgrade one bound service to the other if requested by the client. optval
|
|
|
|
|
must point to an array of two unsigned short ints. The first is the
|
|
|
|
|
service ID to upgrade from and the second the service ID to upgrade to.
|
|
|
|
|
|
2017-06-07 23:27:15 +08:00
|
|
|
(*) RXRPC_SUPPORTED_CMSG
|
|
|
|
|
|
|
|
|
|
This is a read-only option that writes an int into the buffer indicating
|
|
|
|
|
the highest control message type supported.
|
|
|
|
|
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
========
|
|
|
|
|
SECURITY
|
|
|
|
|
========
|
|
|
|
|
|
|
|
|
|
Currently, only the kerberos 4 equivalent protocol has been implemented
|
|
|
|
|
(security index 2 - rxkad). This requires the rxkad module to be loaded and,
|
|
|
|
|
on the client, tickets of the appropriate type to be obtained from the AFS
|
|
|
|
|
kaserver or the kerberos server and installed as "rxrpc" type keys. This is
|
|
|
|
|
normally done using the klog program. An example simple klog program can be
|
|
|
|
|
found at:
|
|
|
|
|
|
|
|
|
|
http://people.redhat.com/~dhowells/rxrpc/klog.c
|
|
|
|
|
|
|
|
|
|
The payload provided to add_key() on the client should be of the following
|
|
|
|
|
form:
|
|
|
|
|
|
|
|
|
|
struct rxrpc_key_sec2_v1 {
|
|
|
|
|
uint16_t security_index; /* 2 */
|
|
|
|
|
uint16_t ticket_length; /* length of ticket[] */
|
|
|
|
|
uint32_t expiry; /* time at which expires */
|
|
|
|
|
uint8_t kvno; /* key version number */
|
|
|
|
|
uint8_t __pad[3];
|
|
|
|
|
uint8_t session_key[8]; /* DES session key */
|
|
|
|
|
uint8_t ticket[0]; /* the encrypted ticket */
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
Where the ticket blob is just appended to the above structure.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
For the server, keys of type "rxrpc_s" must be made available to the server.
|
|
|
|
|
They have a description of "<serviceID>:<securityIndex>" (eg: "52:2" for an
|
|
|
|
|
rxkad key for the AFS VL service). When such a key is created, it should be
|
|
|
|
|
given the server's secret key as the instantiation data (see the example
|
|
|
|
|
below).
|
|
|
|
|
|
|
|
|
|
add_key("rxrpc_s", "52:2", secret_key, 8, keyring);
|
|
|
|
|
|
|
|
|
|
A keyring is passed to the server socket by naming it in a sockopt. The server
|
|
|
|
|
socket then looks the server secret keys up in this keyring when secure
|
|
|
|
|
incoming connections are made. This can be seen in an example program that can
|
|
|
|
|
be found at:
|
|
|
|
|
|
|
|
|
|
http://people.redhat.com/~dhowells/rxrpc/listen.c
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
====================
|
|
|
|
|
EXAMPLE CLIENT USAGE
|
|
|
|
|
====================
|
|
|
|
|
|
|
|
|
|
A client would issue an operation by:
|
|
|
|
|
|
|
|
|
|
(1) An RxRPC socket is set up by:
|
|
|
|
|
|
|
|
|
|
client = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);
|
|
|
|
|
|
|
|
|
|
Where the third parameter indicates the protocol family of the transport
|
|
|
|
|
socket used - usually IPv4 but it can also be IPv6 [TODO].
|
|
|
|
|
|
|
|
|
|
(2) A local address can optionally be bound:
|
|
|
|
|
|
|
|
|
|
struct sockaddr_rxrpc srx = {
|
|
|
|
|
.srx_family = AF_RXRPC,
|
|
|
|
|
.srx_service = 0, /* we're a client */
|
|
|
|
|
.transport_type = SOCK_DGRAM, /* type of transport socket */
|
|
|
|
|
.transport.sin_family = AF_INET,
|
|
|
|
|
.transport.sin_port = htons(7000), /* AFS callback */
|
|
|
|
|
.transport.sin_address = 0, /* all local interfaces */
|
|
|
|
|
};
|
|
|
|
|
bind(client, &srx, sizeof(srx));
|
|
|
|
|
|
|
|
|
|
This specifies the local UDP port to be used. If not given, a random
|
|
|
|
|
non-privileged port will be used. A UDP port may be shared between
|
|
|
|
|
several unrelated RxRPC sockets. Security is handled on a basis of
|
|
|
|
|
per-RxRPC virtual connection.
|
|
|
|
|
|
|
|
|
|
(3) The security is set:
|
|
|
|
|
|
|
|
|
|
const char *key = "AFS:cambridge.redhat.com";
|
|
|
|
|
setsockopt(client, SOL_RXRPC, RXRPC_SECURITY_KEY, key, strlen(key));
|
|
|
|
|
|
|
|
|
|
This issues a request_key() to get the key representing the security
|
|
|
|
|
context. The minimum security level can be set:
|
|
|
|
|
|
|
|
|
|
unsigned int sec = RXRPC_SECURITY_ENCRYPTED;
|
|
|
|
|
setsockopt(client, SOL_RXRPC, RXRPC_MIN_SECURITY_LEVEL,
|
|
|
|
|
&sec, sizeof(sec));
|
|
|
|
|
|
|
|
|
|
(4) The server to be contacted can then be specified (alternatively this can
|
|
|
|
|
be done through sendmsg):
|
|
|
|
|
|
|
|
|
|
struct sockaddr_rxrpc srx = {
|
|
|
|
|
.srx_family = AF_RXRPC,
|
|
|
|
|
.srx_service = VL_SERVICE_ID,
|
|
|
|
|
.transport_type = SOCK_DGRAM, /* type of transport socket */
|
|
|
|
|
.transport.sin_family = AF_INET,
|
|
|
|
|
.transport.sin_port = htons(7005), /* AFS volume manager */
|
|
|
|
|
.transport.sin_address = ...,
|
|
|
|
|
};
|
|
|
|
|
connect(client, &srx, sizeof(srx));
|
|
|
|
|
|
|
|
|
|
(5) The request data should then be posted to the server socket using a series
|
|
|
|
|
of sendmsg() calls, each with the following control message attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_USER_CALL_ID - specifies the user ID for this call
|
|
|
|
|
|
|
|
|
|
MSG_MORE should be set in msghdr::msg_flags on all but the last part of
|
|
|
|
|
the request. Multiple requests may be made simultaneously.
|
|
|
|
|
|
2008-10-17 01:02:37 +08:00
|
|
|
If a call is intended to go to a destination other than the default
|
2007-04-27 06:48:28 +08:00
|
|
|
specified through connect(), then msghdr::msg_name should be set on the
|
|
|
|
|
first request message of that call.
|
|
|
|
|
|
|
|
|
|
(6) The reply data will then be posted to the server socket for recvmsg() to
|
|
|
|
|
pick up. MSG_MORE will be flagged by recvmsg() if there's more reply data
|
|
|
|
|
for a particular call to be read. MSG_EOR will be set on the terminal
|
|
|
|
|
read for a call.
|
|
|
|
|
|
|
|
|
|
All data will be delivered with the following control message attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_USER_CALL_ID - specifies the user ID for this call
|
|
|
|
|
|
|
|
|
|
If an abort or error occurred, this will be returned in the control data
|
|
|
|
|
buffer instead, and MSG_EOR will be flagged to indicate the end of that
|
|
|
|
|
call.
|
|
|
|
|
|
2017-06-05 21:30:49 +08:00
|
|
|
A client may ask for a service ID it knows and ask that this be upgraded to a
|
|
|
|
|
better service if one is available by supplying RXRPC_UPGRADE_SERVICE on the
|
|
|
|
|
first sendmsg() of a call. The client should then check srx_service in the
|
|
|
|
|
msg_name filled in by recvmsg() when collecting the result. srx_service will
|
|
|
|
|
hold the same value as given to sendmsg() if the upgrade request was ignored by
|
|
|
|
|
the service - otherwise it will be altered to indicate the service ID the
|
|
|
|
|
server upgraded to. Note that the upgraded service ID is chosen by the server.
|
|
|
|
|
The caller has to wait until it sees the service ID in the reply before sending
|
|
|
|
|
any more calls (further calls to the same destination will be blocked until the
|
|
|
|
|
probe is concluded).
|
|
|
|
|
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
====================
|
|
|
|
|
EXAMPLE SERVER USAGE
|
|
|
|
|
====================
|
|
|
|
|
|
|
|
|
|
A server would be set up to accept operations in the following manner:
|
|
|
|
|
|
|
|
|
|
(1) An RxRPC socket is created by:
|
|
|
|
|
|
|
|
|
|
server = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);
|
|
|
|
|
|
|
|
|
|
Where the third parameter indicates the address type of the transport
|
|
|
|
|
socket used - usually IPv4.
|
|
|
|
|
|
|
|
|
|
(2) Security is set up if desired by giving the socket a keyring with server
|
|
|
|
|
secret keys in it:
|
|
|
|
|
|
|
|
|
|
keyring = add_key("keyring", "AFSkeys", NULL, 0,
|
|
|
|
|
KEY_SPEC_PROCESS_KEYRING);
|
|
|
|
|
|
|
|
|
|
const char secret_key[8] = {
|
|
|
|
|
0xa7, 0x83, 0x8a, 0xcb, 0xc7, 0x83, 0xec, 0x94 };
|
|
|
|
|
add_key("rxrpc_s", "52:2", secret_key, 8, keyring);
|
|
|
|
|
|
|
|
|
|
setsockopt(server, SOL_RXRPC, RXRPC_SECURITY_KEYRING, "AFSkeys", 7);
|
|
|
|
|
|
|
|
|
|
The keyring can be manipulated after it has been given to the socket. This
|
|
|
|
|
permits the server to add more keys, replace keys, etc. whilst it is live.
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(3) A local address must then be bound:
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
struct sockaddr_rxrpc srx = {
|
|
|
|
|
.srx_family = AF_RXRPC,
|
|
|
|
|
.srx_service = VL_SERVICE_ID, /* RxRPC service ID */
|
|
|
|
|
.transport_type = SOCK_DGRAM, /* type of transport socket */
|
|
|
|
|
.transport.sin_family = AF_INET,
|
|
|
|
|
.transport.sin_port = htons(7000), /* AFS callback */
|
|
|
|
|
.transport.sin_address = 0, /* all local interfaces */
|
|
|
|
|
};
|
|
|
|
|
bind(server, &srx, sizeof(srx));
|
|
|
|
|
|
2017-06-05 21:30:49 +08:00
|
|
|
More than one service ID may be bound to a socket, provided the transport
|
|
|
|
|
parameters are the same. The limit is currently two. To do this, bind()
|
|
|
|
|
should be called twice.
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(4) If service upgrading is required, first two service IDs must have been
|
|
|
|
|
bound and then the following option must be set:
|
|
|
|
|
|
|
|
|
|
unsigned short service_ids[2] = { from_ID, to_ID };
|
|
|
|
|
setsockopt(server, SOL_RXRPC, RXRPC_UPGRADEABLE_SERVICE,
|
|
|
|
|
service_ids, sizeof(service_ids));
|
|
|
|
|
|
|
|
|
|
This will automatically upgrade connections on service from_ID to service
|
|
|
|
|
to_ID if they request it. This will be reflected in msg_name obtained
|
|
|
|
|
through recvmsg() when the request data is delivered to userspace.
|
|
|
|
|
|
|
|
|
|
(5) The server is then set to listen out for incoming calls:
|
2007-04-27 06:48:28 +08:00
|
|
|
|
|
|
|
|
listen(server, 100);
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(6) The kernel notifies the server of pending incoming connections by sending
|
2007-04-27 06:48:28 +08:00
|
|
|
it a message for each. This is received with recvmsg() on the server
|
|
|
|
|
socket. It has no data, and has a single dataless control message
|
|
|
|
|
attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_NEW_CALL
|
|
|
|
|
|
|
|
|
|
The address that can be passed back by recvmsg() at this point should be
|
|
|
|
|
ignored since the call for which the message was posted may have gone by
|
|
|
|
|
the time it is accepted - in which case the first call still on the queue
|
|
|
|
|
will be accepted.
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(7) The server then accepts the new call by issuing a sendmsg() with two
|
2007-04-27 06:48:28 +08:00
|
|
|
pieces of control data and no actual data:
|
|
|
|
|
|
|
|
|
|
RXRPC_ACCEPT - indicate connection acceptance
|
|
|
|
|
RXRPC_USER_CALL_ID - specify user ID for this call
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(8) The first request data packet will then be posted to the server socket for
|
2007-04-27 06:48:28 +08:00
|
|
|
recvmsg() to pick up. At that point, the RxRPC address for the call can
|
|
|
|
|
be read from the address fields in the msghdr struct.
|
|
|
|
|
|
|
|
|
|
Subsequent request data will be posted to the server socket for recvmsg()
|
|
|
|
|
to collect as it arrives. All but the last piece of the request data will
|
|
|
|
|
be delivered with MSG_MORE flagged.
|
|
|
|
|
|
|
|
|
|
All data will be delivered with the following control message attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_USER_CALL_ID - specifies the user ID for this call
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(9) The reply data should then be posted to the server socket using a series
|
2007-04-27 06:48:28 +08:00
|
|
|
of sendmsg() calls, each with the following control messages attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_USER_CALL_ID - specifies the user ID for this call
|
|
|
|
|
|
|
|
|
|
MSG_MORE should be set in msghdr::msg_flags on all but the last message
|
|
|
|
|
for a particular call.
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(10) The final ACK from the client will be posted for retrieval by recvmsg()
|
2007-04-27 06:48:28 +08:00
|
|
|
when it is received. It will take the form of a dataless message with two
|
|
|
|
|
control messages attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_USER_CALL_ID - specifies the user ID for this call
|
|
|
|
|
RXRPC_ACK - indicates final ACK (no data)
|
|
|
|
|
|
|
|
|
|
MSG_EOR will be flagged to indicate that this is the final message for
|
|
|
|
|
this call.
|
|
|
|
|
|
rxrpc: Implement service upgrade
Implement AuriStor's service upgrade facility. There are three problems
that this is meant to deal with:
(1) Various of the standard AFS RPC calls have IPv4 addresses in their
requests and/or replies - but there's no room for including IPv6
addresses.
(2) Definition of IPv6-specific RPC operations in the standard operation
sets has not yet been achieved.
(3) One could envision the creation a new service on the same port that as
the original service. The new service could implement improved
operations - and the client could try this first, falling back to the
original service if it's not there.
Unfortunately, certain servers ignore packets addressed to a service
they don't implement and don't respond in any way - not even with an
ABORT. This means that the client must then wait for the call timeout
to occur.
What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats. Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.
In the protocol, the procedure is then as follows:
(1) To request an upgrade, the first DATA packet in a new connection must
have the userStatus set to 1 (this is normally 0). The userStatus
value is normally ignored by the server.
(2) If the server doesn't support upgrading, the reply packets will
contain the same service ID as for the first request packet.
(3) If the server does support upgrading, all future reply packets on that
connection will contain the new service ID and the new service ID will
be applied to *all* further calls on that connection as well.
(4) The RPC op used to probe the upgrade must take the same request data
as the shadow call in the upgrade set (but may return a different
reply). GetCapability RPC ops were added to all standard sets for
just this purpose. Ops where the request formats differ cannot be
used for probing.
(5) The client must wait for completion of the probe before sending any
further RPC ops to the same destination. It should then use the
service ID that recvmsg() reported back in all future calls.
(6) The shadow service must have call definitions for all the operation
IDs defined by the original service.
To support service upgrading, a server should:
(1) Call bind() twice on its AF_RXRPC socket before calling listen().
Each bind() should supply a different service ID, but the transport
addresses must be the same. This allows the server to receive
requests with either service ID.
(2) Enable automatic upgrading by calling setsockopt(), specifying
RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
unsigned shorts as the argument:
unsigned short optval[2];
This specifies a pair of service IDs. They must be different and must
match the service IDs bound to the socket. Member 0 is the service ID
to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 21:30:49 +08:00
|
|
|
(11) Up to the point the final packet of reply data is sent, the call can be
|
2007-04-27 06:48:28 +08:00
|
|
|
aborted by calling sendmsg() with a dataless message with the following
|
|
|
|
|
control messages attached:
|
|
|
|
|
|
|
|
|
|
RXRPC_USER_CALL_ID - specifies the user ID for this call
|
|
|
|
|
RXRPC_ABORT - indicates abort code (4 byte data)
|
|
|
|
|
|
|
|
|
|
Any packets waiting in the socket's receive queue will be discarded if
|
|
|
|
|
this is issued.
|
|
|
|
|
|
|
|
|
|
Note that all the communications for a particular service take place through
|
|
|
|
|
the one server socket, using control messages on sendmsg() and recvmsg() to
|
|
|
|
|
determine the call affected.
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
|
|
|
|
|
|
|
|
|
|
=========================
|
|
|
|
|
AF_RXRPC KERNEL INTERFACE
|
|
|
|
|
=========================
|
|
|
|
|
|
|
|
|
|
The AF_RXRPC module also provides an interface for use by in-kernel utilities
|
|
|
|
|
such as the AFS filesystem. This permits such a utility to:
|
|
|
|
|
|
|
|
|
|
(1) Use different keys directly on individual client calls on one socket
|
|
|
|
|
rather than having to open a whole slew of sockets, one for each key it
|
|
|
|
|
might want to use.
|
|
|
|
|
|
|
|
|
|
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
|
|
|
|
|
opening of a socket. Instead the utility is responsible for requesting a
|
|
|
|
|
key at the appropriate point. AFS, for instance, would do this during VFS
|
|
|
|
|
operations such as open() or unlink(). The key is then handed through
|
|
|
|
|
when the call is initiated.
|
|
|
|
|
|
|
|
|
|
(3) Request the use of something other than GFP_KERNEL to allocate memory.
|
|
|
|
|
|
|
|
|
|
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
|
|
|
|
|
intercepted before they get put into the socket Rx queue and the socket
|
|
|
|
|
buffers manipulated directly.
|
|
|
|
|
|
|
|
|
|
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
|
2007-10-20 07:34:40 +08:00
|
|
|
bind an address as appropriate and listen if it's to be a server socket, but
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
then it passes this to the kernel interface functions.
|
|
|
|
|
|
|
|
|
|
The kernel interface functions are as follows:
|
|
|
|
|
|
|
|
|
|
(*) Begin a new client call.
|
|
|
|
|
|
|
|
|
|
struct rxrpc_call *
|
|
|
|
|
rxrpc_kernel_begin_call(struct socket *sock,
|
|
|
|
|
struct sockaddr_rxrpc *srx,
|
|
|
|
|
struct key *key,
|
|
|
|
|
unsigned long user_call_ID,
|
|
|
|
|
gfp_t gfp);
|
|
|
|
|
|
|
|
|
|
This allocates the infrastructure to make a new RxRPC call and assigns
|
|
|
|
|
call and connection numbers. The call will be made on the UDP port that
|
|
|
|
|
the socket is bound to. The call will go to the destination address of a
|
|
|
|
|
connected client socket unless an alternative is supplied (srx is
|
|
|
|
|
non-NULL).
|
|
|
|
|
|
|
|
|
|
If a key is supplied then this will be used to secure the call instead of
|
|
|
|
|
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
|
|
|
|
|
secured in this way will still share connections if at all possible.
|
|
|
|
|
|
|
|
|
|
The user_call_ID is equivalent to that supplied to sendmsg() in the
|
|
|
|
|
control data buffer. It is entirely feasible to use this to point to a
|
|
|
|
|
kernel data structure.
|
|
|
|
|
|
|
|
|
|
If this function is successful, an opaque reference to the RxRPC call is
|
|
|
|
|
returned. The caller now holds a reference on this and it must be
|
|
|
|
|
properly ended.
|
|
|
|
|
|
|
|
|
|
(*) End a client call.
|
|
|
|
|
|
2016-08-30 19:00:48 +08:00
|
|
|
void rxrpc_kernel_end_call(struct socket *sock,
|
|
|
|
|
struct rxrpc_call *call);
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
|
|
|
|
|
This is used to end a previously begun call. The user_call_ID is expunged
|
|
|
|
|
from AF_RXRPC's knowledge and will not be seen again in association with
|
|
|
|
|
the specified call.
|
|
|
|
|
|
|
|
|
|
(*) Send data through a call.
|
|
|
|
|
|
2016-08-30 19:00:48 +08:00
|
|
|
int rxrpc_kernel_send_data(struct socket *sock,
|
|
|
|
|
struct rxrpc_call *call,
|
|
|
|
|
struct msghdr *msg,
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
size_t len);
|
|
|
|
|
|
|
|
|
|
This is used to supply either the request part of a client call or the
|
|
|
|
|
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
|
|
|
|
|
data buffers to be used. msg_iov may not be NULL and must point
|
|
|
|
|
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
|
|
|
|
|
MSG_MORE if there will be subsequent data sends for this call.
|
|
|
|
|
|
|
|
|
|
The msg must not specify a destination address, control data or any flags
|
|
|
|
|
other than MSG_MORE. len is the total amount of data to transmit.
|
|
|
|
|
|
rxrpc: Don't expose skbs to in-kernel users [ver #2]
Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.
This makes the following possibilities more achievable:
(1) Call refcounting can be made simpler if skbs don't hold refs to calls.
(2) skbs referring to non-data events will be able to be freed much sooner
rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
will be able to consult the call state.
(3) We can shortcut the receive phase when a call is remotely aborted
because we don't have to go through all the packets to get to the one
cancelling the operation.
(4) It makes it easier to do encryption/decryption directly between AFS's
buffers and sk_buffs.
(5) Encryption/decryption can more easily be done in the AFS's thread
contexts - usually that of the userspace process that issued a syscall
- rather than in one of rxrpc's background threads on a workqueue.
(6) AFS will be able to wait synchronously on a call inside AF_RXRPC.
To make this work, the following interface function has been added:
int rxrpc_kernel_recv_data(
struct socket *sock, struct rxrpc_call *call,
void *buffer, size_t bufsize, size_t *_offset,
bool want_more, u32 *_abort_code);
This is the recvmsg equivalent. It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.
afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them. They don't wait synchronously yet because the socket
lock needs to be dealt with.
Five interface functions have been removed:
rxrpc_kernel_is_data_last()
rxrpc_kernel_get_abort_code()
rxrpc_kernel_get_error_number()
rxrpc_kernel_free_skb()
rxrpc_kernel_data_consumed()
As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user. To process the queue internally, a temporary function,
temp_deliver_data() has been added. This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-31 03:42:14 +08:00
|
|
|
(*) Receive data from a call.
|
|
|
|
|
|
|
|
|
|
int rxrpc_kernel_recv_data(struct socket *sock,
|
|
|
|
|
struct rxrpc_call *call,
|
|
|
|
|
void *buf,
|
|
|
|
|
size_t size,
|
|
|
|
|
size_t *_offset,
|
|
|
|
|
bool want_more,
|
|
|
|
|
u32 *_abort)
|
|
|
|
|
|
|
|
|
|
This is used to receive data from either the reply part of a client call
|
|
|
|
|
or the request part of a service call. buf and size specify how much
|
|
|
|
|
data is desired and where to store it. *_offset is added on to buf and
|
|
|
|
|
subtracted from size internally; the amount copied into the buffer is
|
|
|
|
|
added to *_offset before returning.
|
|
|
|
|
|
|
|
|
|
want_more should be true if further data will be required after this is
|
|
|
|
|
satisfied and false if this is the last item of the receive phase.
|
|
|
|
|
|
|
|
|
|
There are three normal returns: 0 if the buffer was filled and want_more
|
|
|
|
|
was true; 1 if the buffer was filled, the last DATA packet has been
|
|
|
|
|
emptied and want_more was false; and -EAGAIN if the function needs to be
|
|
|
|
|
called again.
|
|
|
|
|
|
|
|
|
|
If the last DATA packet is processed but the buffer contains less than
|
|
|
|
|
the amount requested, EBADMSG is returned. If want_more wasn't set, but
|
|
|
|
|
more data was available, EMSGSIZE is returned.
|
|
|
|
|
|
|
|
|
|
If a remote ABORT is detected, the abort code received will be stored in
|
|
|
|
|
*_abort and ECONNABORTED will be returned.
|
|
|
|
|
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
(*) Abort a call.
|
|
|
|
|
|
2016-08-30 19:00:48 +08:00
|
|
|
void rxrpc_kernel_abort_call(struct socket *sock,
|
|
|
|
|
struct rxrpc_call *call,
|
|
|
|
|
u32 abort_code);
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
|
|
|
|
|
This is used to abort a call if it's still in an abortable state. The
|
|
|
|
|
abort code specified will be placed in the ABORT message sent.
|
|
|
|
|
|
|
|
|
|
(*) Intercept received RxRPC messages.
|
|
|
|
|
|
|
|
|
|
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
|
|
|
|
|
unsigned long user_call_ID,
|
|
|
|
|
struct sk_buff *skb);
|
|
|
|
|
|
|
|
|
|
void
|
|
|
|
|
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
|
|
|
|
|
rxrpc_interceptor_t interceptor);
|
|
|
|
|
|
|
|
|
|
This installs an interceptor function on the specified AF_RXRPC socket.
|
|
|
|
|
All messages that would otherwise wind up in the socket's Rx queue are
|
|
|
|
|
then diverted to this function. Note that care must be taken to process
|
|
|
|
|
the messages in the right order to maintain DATA message sequentiality.
|
|
|
|
|
|
|
|
|
|
The interceptor function itself is provided with the address of the socket
|
|
|
|
|
and handling the incoming message, the ID assigned by the kernel utility
|
|
|
|
|
to the call and the socket buffer containing the message.
|
|
|
|
|
|
|
|
|
|
The skb->mark field indicates the type of message:
|
|
|
|
|
|
|
|
|
|
MARK MEANING
|
|
|
|
|
=============================== =======================================
|
|
|
|
|
RXRPC_SKB_MARK_DATA Data message
|
|
|
|
|
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
|
|
|
|
|
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
|
|
|
|
|
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
|
|
|
|
|
RXRPC_SKB_MARK_NET_ERROR Network error detected
|
|
|
|
|
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
|
|
|
|
|
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
|
|
|
|
|
|
|
|
|
|
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
|
|
|
|
|
The two error messages can be probed with rxrpc_kernel_get_error_number().
|
|
|
|
|
A new call can be accepted with rxrpc_kernel_accept_call().
|
|
|
|
|
|
|
|
|
|
Data messages can have their contents extracted with the usual bunch of
|
|
|
|
|
socket buffer manipulation functions. A data message can be determined to
|
|
|
|
|
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
|
rxrpc: Fix races between skb free, ACK generation and replying
Inside the kafs filesystem it is possible to occasionally have a call
processed and terminated before we've had a chance to check whether we need
to clean up the rx queue for that call because afs_send_simple_reply() ends
the call when it is done, but this is done in a workqueue item that might
happen to run to completion before afs_deliver_to_call() completes.
Further, it is possible for rxrpc_kernel_send_data() to be called to send a
reply before the last request-phase data skb is released. The rxrpc skb
destructor is where the ACK processing is done and the call state is
advanced upon release of the last skb. ACK generation is also deferred to
a work item because it's possible that the skb destructor is not called in
a context where kernel_sendmsg() can be invoked.
To this end, the following changes are made:
(1) kernel_rxrpc_data_consumed() is added. This should be called whenever
an skb is emptied so as to crank the ACK and call states. This does
not release the skb, however. kernel_rxrpc_free_skb() must now be
called to achieve that. These together replace
rxrpc_kernel_data_delivered().
(2) kernel_rxrpc_data_consumed() is wrapped by afs_data_consumed().
This makes afs_deliver_to_call() easier to work as the skb can simply
be discarded unconditionally here without trying to work out what the
return value of the ->deliver() function means.
The ->deliver() functions can, via afs_data_complete(),
afs_transfer_reply() and afs_extract_data() mark that an skb has been
consumed (thereby cranking the state) without the need to
conditionally free the skb to make sure the state is correct on an
incoming call for when the call processor tries to send the reply.
(3) rxrpc_recvmsg() now has to call kernel_rxrpc_data_consumed() when it
has finished with a packet and MSG_PEEK isn't set.
(4) rxrpc_packet_destructor() no longer calls rxrpc_hard_ACK_data().
Because of this, we no longer need to clear the destructor and put the
call before we free the skb in cases where we don't want the ACK/call
state to be cranked.
(5) The ->deliver() call-type callbacks are made to return -EAGAIN rather
than 0 if they expect more data (afs_extract_data() returns -EAGAIN to
the delivery function already), and the caller is now responsible for
producing an abort if that was the last packet.
(6) There are many bits of unmarshalling code where:
ret = afs_extract_data(call, skb, last, ...);
switch (ret) {
case 0: break;
case -EAGAIN: return 0;
default: return ret;
}
is to be found. As -EAGAIN can now be passed back to the caller, we
now just return if ret < 0:
ret = afs_extract_data(call, skb, last, ...);
if (ret < 0)
return ret;
(7) Checks for trailing data and empty final data packets has been
consolidated as afs_data_complete(). So:
if (skb->len > 0)
return -EBADMSG;
if (!last)
return 0;
becomes:
ret = afs_data_complete(call, skb, last);
if (ret < 0)
return ret;
(8) afs_transfer_reply() now checks the amount of data it has against the
amount of data desired and the amount of data in the skb and returns
an error to induce an abort if we don't get exactly what we want.
Without these changes, the following oops can occasionally be observed,
particularly if some printks are inserted into the delivery path:
general protection fault: 0000 [#1] SMP
Modules linked in: kafs(E) af_rxrpc(E) [last unloaded: af_rxrpc]
CPU: 0 PID: 1305 Comm: kworker/u8:3 Tainted: G E 4.7.0-fsdevel+ #1303
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Workqueue: kafsd afs_async_workfn [kafs]
task: ffff88040be041c0 ti: ffff88040c070000 task.ti: ffff88040c070000
RIP: 0010:[<ffffffff8108fd3c>] [<ffffffff8108fd3c>] __lock_acquire+0xcf/0x15a1
RSP: 0018:ffff88040c073bc0 EFLAGS: 00010002
RAX: 6b6b6b6b6b6b6b6b RBX: 0000000000000000 RCX: ffff88040d29a710
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88040d29a710
RBP: ffff88040c073c70 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88040be041c0 R15: ffffffff814c928f
FS: 0000000000000000(0000) GS:ffff88041fa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa4595f4750 CR3: 0000000001c14000 CR4: 00000000001406f0
Stack:
0000000000000006 000000000be04930 0000000000000000 ffff880400000000
ffff880400000000 ffffffff8108f847 ffff88040be041c0 ffffffff81050446
ffff8803fc08a920 ffff8803fc08a958 ffff88040be041c0 ffff88040c073c38
Call Trace:
[<ffffffff8108f847>] ? mark_held_locks+0x5e/0x74
[<ffffffff81050446>] ? __local_bh_enable_ip+0x9b/0xa1
[<ffffffff8108f9ca>] ? trace_hardirqs_on_caller+0x16d/0x189
[<ffffffff810915f4>] lock_acquire+0x122/0x1b6
[<ffffffff810915f4>] ? lock_acquire+0x122/0x1b6
[<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
[<ffffffff81609dbf>] _raw_spin_lock_irqsave+0x35/0x49
[<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
[<ffffffff814c928f>] skb_dequeue+0x18/0x61
[<ffffffffa009aa92>] afs_deliver_to_call+0x344/0x39d [kafs]
[<ffffffffa009ab37>] afs_process_async_call+0x4c/0xd5 [kafs]
[<ffffffffa0099e9c>] afs_async_workfn+0xe/0x10 [kafs]
[<ffffffff81063a3a>] process_one_work+0x29d/0x57c
[<ffffffff81064ac2>] worker_thread+0x24a/0x385
[<ffffffff81064878>] ? rescuer_thread+0x2d0/0x2d0
[<ffffffff810696f5>] kthread+0xf3/0xfb
[<ffffffff8160a6ff>] ret_from_fork+0x1f/0x40
[<ffffffff81069602>] ? kthread_create_on_node+0x1cf/0x1cf
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-03 21:11:40 +08:00
|
|
|
data message has been used up, rxrpc_kernel_data_consumed() should be
|
|
|
|
|
called on it.
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
|
rxrpc: Fix races between skb free, ACK generation and replying
Inside the kafs filesystem it is possible to occasionally have a call
processed and terminated before we've had a chance to check whether we need
to clean up the rx queue for that call because afs_send_simple_reply() ends
the call when it is done, but this is done in a workqueue item that might
happen to run to completion before afs_deliver_to_call() completes.
Further, it is possible for rxrpc_kernel_send_data() to be called to send a
reply before the last request-phase data skb is released. The rxrpc skb
destructor is where the ACK processing is done and the call state is
advanced upon release of the last skb. ACK generation is also deferred to
a work item because it's possible that the skb destructor is not called in
a context where kernel_sendmsg() can be invoked.
To this end, the following changes are made:
(1) kernel_rxrpc_data_consumed() is added. This should be called whenever
an skb is emptied so as to crank the ACK and call states. This does
not release the skb, however. kernel_rxrpc_free_skb() must now be
called to achieve that. These together replace
rxrpc_kernel_data_delivered().
(2) kernel_rxrpc_data_consumed() is wrapped by afs_data_consumed().
This makes afs_deliver_to_call() easier to work as the skb can simply
be discarded unconditionally here without trying to work out what the
return value of the ->deliver() function means.
The ->deliver() functions can, via afs_data_complete(),
afs_transfer_reply() and afs_extract_data() mark that an skb has been
consumed (thereby cranking the state) without the need to
conditionally free the skb to make sure the state is correct on an
incoming call for when the call processor tries to send the reply.
(3) rxrpc_recvmsg() now has to call kernel_rxrpc_data_consumed() when it
has finished with a packet and MSG_PEEK isn't set.
(4) rxrpc_packet_destructor() no longer calls rxrpc_hard_ACK_data().
Because of this, we no longer need to clear the destructor and put the
call before we free the skb in cases where we don't want the ACK/call
state to be cranked.
(5) The ->deliver() call-type callbacks are made to return -EAGAIN rather
than 0 if they expect more data (afs_extract_data() returns -EAGAIN to
the delivery function already), and the caller is now responsible for
producing an abort if that was the last packet.
(6) There are many bits of unmarshalling code where:
ret = afs_extract_data(call, skb, last, ...);
switch (ret) {
case 0: break;
case -EAGAIN: return 0;
default: return ret;
}
is to be found. As -EAGAIN can now be passed back to the caller, we
now just return if ret < 0:
ret = afs_extract_data(call, skb, last, ...);
if (ret < 0)
return ret;
(7) Checks for trailing data and empty final data packets has been
consolidated as afs_data_complete(). So:
if (skb->len > 0)
return -EBADMSG;
if (!last)
return 0;
becomes:
ret = afs_data_complete(call, skb, last);
if (ret < 0)
return ret;
(8) afs_transfer_reply() now checks the amount of data it has against the
amount of data desired and the amount of data in the skb and returns
an error to induce an abort if we don't get exactly what we want.
Without these changes, the following oops can occasionally be observed,
particularly if some printks are inserted into the delivery path:
general protection fault: 0000 [#1] SMP
Modules linked in: kafs(E) af_rxrpc(E) [last unloaded: af_rxrpc]
CPU: 0 PID: 1305 Comm: kworker/u8:3 Tainted: G E 4.7.0-fsdevel+ #1303
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Workqueue: kafsd afs_async_workfn [kafs]
task: ffff88040be041c0 ti: ffff88040c070000 task.ti: ffff88040c070000
RIP: 0010:[<ffffffff8108fd3c>] [<ffffffff8108fd3c>] __lock_acquire+0xcf/0x15a1
RSP: 0018:ffff88040c073bc0 EFLAGS: 00010002
RAX: 6b6b6b6b6b6b6b6b RBX: 0000000000000000 RCX: ffff88040d29a710
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88040d29a710
RBP: ffff88040c073c70 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88040be041c0 R15: ffffffff814c928f
FS: 0000000000000000(0000) GS:ffff88041fa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa4595f4750 CR3: 0000000001c14000 CR4: 00000000001406f0
Stack:
0000000000000006 000000000be04930 0000000000000000 ffff880400000000
ffff880400000000 ffffffff8108f847 ffff88040be041c0 ffffffff81050446
ffff8803fc08a920 ffff8803fc08a958 ffff88040be041c0 ffff88040c073c38
Call Trace:
[<ffffffff8108f847>] ? mark_held_locks+0x5e/0x74
[<ffffffff81050446>] ? __local_bh_enable_ip+0x9b/0xa1
[<ffffffff8108f9ca>] ? trace_hardirqs_on_caller+0x16d/0x189
[<ffffffff810915f4>] lock_acquire+0x122/0x1b6
[<ffffffff810915f4>] ? lock_acquire+0x122/0x1b6
[<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
[<ffffffff81609dbf>] _raw_spin_lock_irqsave+0x35/0x49
[<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
[<ffffffff814c928f>] skb_dequeue+0x18/0x61
[<ffffffffa009aa92>] afs_deliver_to_call+0x344/0x39d [kafs]
[<ffffffffa009ab37>] afs_process_async_call+0x4c/0xd5 [kafs]
[<ffffffffa0099e9c>] afs_async_workfn+0xe/0x10 [kafs]
[<ffffffff81063a3a>] process_one_work+0x29d/0x57c
[<ffffffff81064ac2>] worker_thread+0x24a/0x385
[<ffffffff81064878>] ? rescuer_thread+0x2d0/0x2d0
[<ffffffff810696f5>] kthread+0xf3/0xfb
[<ffffffff8160a6ff>] ret_from_fork+0x1f/0x40
[<ffffffff81069602>] ? kthread_create_on_node+0x1cf/0x1cf
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-03 21:11:40 +08:00
|
|
|
Messages should be handled to rxrpc_kernel_free_skb() to dispose of. It
|
|
|
|
|
is possible to get extra refs on all types of message for later freeing,
|
|
|
|
|
but this may pin the state of a call until the message is finally freed.
|
[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available. AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.
This permits AFS (or whatever) to:
(1) Avoid the overhead of using the recvmsg() call.
(2) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(3) Avoid calling request_key() at the point of issue of a call or opening of
a socket. This is done instead by AFS at the point of open(), unlink() or
other VFS operation and the key handed through.
(4) Request the use of something other than GFP_KERNEL to allocate memory.
Furthermore:
(*) The socket buffer markings used by RxRPC are made available for AFS so
that it can interpret the cooked RxRPC messages itself.
(*) rxgen (un)marshalling abort codes are made available.
The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:
=========================
AF_RXRPC KERNEL INTERFACE
=========================
The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem. This permits such a utility to:
(1) Use different keys directly on individual client calls on one socket
rather than having to open a whole slew of sockets, one for each key it
might want to use.
(2) Avoid having RxRPC call request_key() at the point of issue of a call or
opening of a socket. Instead the utility is responsible for requesting a
key at the appropriate point. AFS, for instance, would do this during VFS
operations such as open() or unlink(). The key is then handed through
when the call is initiated.
(3) Request the use of something other than GFP_KERNEL to allocate memory.
(4) Avoid the overhead of using the recvmsg() call. RxRPC messages can be
intercepted before they get put into the socket Rx queue and the socket
buffers manipulated directly.
To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.
The kernel interface functions are as follows:
(*) Begin a new client call.
struct rxrpc_call *
rxrpc_kernel_begin_call(struct socket *sock,
struct sockaddr_rxrpc *srx,
struct key *key,
unsigned long user_call_ID,
gfp_t gfp);
This allocates the infrastructure to make a new RxRPC call and assigns
call and connection numbers. The call will be made on the UDP port that
the socket is bound to. The call will go to the destination address of a
connected client socket unless an alternative is supplied (srx is
non-NULL).
If a key is supplied then this will be used to secure the call instead of
the key bound to the socket with the RXRPC_SECURITY_KEY sockopt. Calls
secured in this way will still share connections if at all possible.
The user_call_ID is equivalent to that supplied to sendmsg() in the
control data buffer. It is entirely feasible to use this to point to a
kernel data structure.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) End a client call.
void rxrpc_kernel_end_call(struct rxrpc_call *call);
This is used to end a previously begun call. The user_call_ID is expunged
from AF_RXRPC's knowledge and will not be seen again in association with
the specified call.
(*) Send data through a call.
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len);
This is used to supply either the request part of a client call or the
reply part of a server call. msg.msg_iovlen and msg.msg_iov specify the
data buffers to be used. msg_iov may not be NULL and must point
exclusively to in-kernel virtual addresses. msg.msg_flags may be given
MSG_MORE if there will be subsequent data sends for this call.
The msg must not specify a destination address, control data or any flags
other than MSG_MORE. len is the total amount of data to transmit.
(*) Abort a call.
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
This is used to abort a call if it's still in an abortable state. The
abort code specified will be placed in the ABORT message sent.
(*) Intercept received RxRPC messages.
typedef void (*rxrpc_interceptor_t)(struct sock *sk,
unsigned long user_call_ID,
struct sk_buff *skb);
void
rxrpc_kernel_intercept_rx_messages(struct socket *sock,
rxrpc_interceptor_t interceptor);
This installs an interceptor function on the specified AF_RXRPC socket.
All messages that would otherwise wind up in the socket's Rx queue are
then diverted to this function. Note that care must be taken to process
the messages in the right order to maintain DATA message sequentiality.
The interceptor function itself is provided with the address of the socket
and handling the incoming message, the ID assigned by the kernel utility
to the call and the socket buffer containing the message.
The skb->mark field indicates the type of message:
MARK MEANING
=============================== =======================================
RXRPC_SKB_MARK_DATA Data message
RXRPC_SKB_MARK_FINAL_ACK Final ACK received for an incoming call
RXRPC_SKB_MARK_BUSY Client call rejected as server busy
RXRPC_SKB_MARK_REMOTE_ABORT Call aborted by peer
RXRPC_SKB_MARK_NET_ERROR Network error detected
RXRPC_SKB_MARK_LOCAL_ERROR Local error encountered
RXRPC_SKB_MARK_NEW_CALL New incoming call awaiting acceptance
The remote abort message can be probed with rxrpc_kernel_get_abort_code().
The two error messages can be probed with rxrpc_kernel_get_error_number().
A new call can be accepted with rxrpc_kernel_accept_call().
Data messages can have their contents extracted with the usual bunch of
socket buffer manipulation functions. A data message can be determined to
be the last one in a sequence with rxrpc_kernel_is_data_last(). When a
data message has been used up, rxrpc_kernel_data_delivered() should be
called on it..
Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
of. It is possible to get extra refs on all types of message for later
freeing, but this may pin the state of a call until the message is finally
freed.
(*) Accept an incoming call.
struct rxrpc_call *
rxrpc_kernel_accept_call(struct socket *sock,
unsigned long user_call_ID);
This is used to accept an incoming call and to assign it a call ID. This
function is similar to rxrpc_kernel_begin_call() and calls accepted must
be ended in the same way.
If this function is successful, an opaque reference to the RxRPC call is
returned. The caller now holds a reference on this and it must be
properly ended.
(*) Reject an incoming call.
int rxrpc_kernel_reject_call(struct socket *sock);
This is used to reject the first incoming call on the socket's queue with
a BUSY message. -ENODATA is returned if there were no incoming calls.
Other errors may be returned if the call had been aborted (-ECONNABORTED)
or had timed out (-ETIME).
(*) Record the delivery of a data message and free it.
void rxrpc_kernel_data_delivered(struct sk_buff *skb);
This is used to record a data message as having been delivered and to
update the ACK state for the call. The socket buffer will be freed.
(*) Free a message.
void rxrpc_kernel_free_skb(struct sk_buff *skb);
This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
socket.
(*) Determine if a data message is the last one on a call.
bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
This is used to determine if a socket buffer holds the last data message
to be received for a call (true will be returned if it does, false
if not).
The data message will be part of the reply on a client call and the
request on an incoming call. In the latter case there will be more
messages, but in the former case there will not.
(*) Get the abort code from an abort message.
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
This is used to extract the abort code from a remote abort message.
(*) Get the error number from a local or network error message.
int rxrpc_kernel_get_error_number(struct sk_buff *skb);
This is used to extract the error number from a message indicating either
a local error occurred or a network error occurred.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-27 06:50:17 +08:00
|
|
|
|
|
|
|
|
(*) Accept an incoming call.
|
|
|
|
|
|
|
|
|
|
struct rxrpc_call *
|
|
|
|
|
rxrpc_kernel_accept_call(struct socket *sock,
|
|
|
|
|
unsigned long user_call_ID);
|
|
|
|
|
|
|
|
|
|
This is used to accept an incoming call and to assign it a call ID. This
|
|
|
|
|
function is similar to rxrpc_kernel_begin_call() and calls accepted must
|
|
|
|
|
be ended in the same way.
|
|
|
|
|
|
|
|
|
|
If this function is successful, an opaque reference to the RxRPC call is
|
|
|
|
|
returned. The caller now holds a reference on this and it must be
|
|
|
|
|
properly ended.
|
|
|
|
|
|
|
|
|
|
(*) Reject an incoming call.
|
|
|
|
|
|
|
|
|
|
int rxrpc_kernel_reject_call(struct socket *sock);
|
|
|
|
|
|
|
|
|
|
This is used to reject the first incoming call on the socket's queue with
|
|
|
|
|
a BUSY message. -ENODATA is returned if there were no incoming calls.
|
|
|
|
|
Other errors may be returned if the call had been aborted (-ECONNABORTED)
|
|
|
|
|
or had timed out (-ETIME).
|
|
|
|
|
|
2007-10-17 14:29:46 +08:00
|
|
|
(*) Allocate a null key for doing anonymous security.
|
|
|
|
|
|
|
|
|
|
struct key *rxrpc_get_null_key(const char *keyname);
|
|
|
|
|
|
|
|
|
|
This is used to allocate a null RxRPC key that can be used to indicate
|
|
|
|
|
anonymous security for a particular domain.
|
2014-02-08 02:58:44 +08:00
|
|
|
|
2016-08-30 16:49:29 +08:00
|
|
|
(*) Get the peer address of a call.
|
|
|
|
|
|
|
|
|
|
void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
|
|
|
|
|
struct sockaddr_rxrpc *_srx);
|
|
|
|
|
|
|
|
|
|
This is used to find the remote peer address of a call.
|
|
|
|
|
|
2014-02-08 02:58:44 +08:00
|
|
|
|
|
|
|
|
=======================
|
|
|
|
|
CONFIGURABLE PARAMETERS
|
|
|
|
|
=======================
|
|
|
|
|
|
|
|
|
|
The RxRPC protocol driver has a number of configurable parameters that can be
|
|
|
|
|
adjusted through sysctls in /proc/net/rxrpc/:
|
|
|
|
|
|
|
|
|
|
(*) req_ack_delay
|
|
|
|
|
|
|
|
|
|
The amount of time in milliseconds after receiving a packet with the
|
|
|
|
|
request-ack flag set before we honour the flag and actually send the
|
|
|
|
|
requested ack.
|
|
|
|
|
|
|
|
|
|
Usually the other side won't stop sending packets until the advertised
|
|
|
|
|
reception window is full (to a maximum of 255 packets), so delaying the
|
|
|
|
|
ACK permits several packets to be ACK'd in one go.
|
|
|
|
|
|
|
|
|
|
(*) soft_ack_delay
|
|
|
|
|
|
|
|
|
|
The amount of time in milliseconds after receiving a new packet before we
|
|
|
|
|
generate a soft-ACK to tell the sender that it doesn't need to resend.
|
|
|
|
|
|
|
|
|
|
(*) idle_ack_delay
|
|
|
|
|
|
|
|
|
|
The amount of time in milliseconds after all the packets currently in the
|
|
|
|
|
received queue have been consumed before we generate a hard-ACK to tell
|
|
|
|
|
the sender it can free its buffers, assuming no other reason occurs that
|
|
|
|
|
we would send an ACK.
|
|
|
|
|
|
|
|
|
|
(*) resend_timeout
|
|
|
|
|
|
|
|
|
|
The amount of time in milliseconds after transmitting a packet before we
|
|
|
|
|
transmit it again, assuming no ACK is received from the receiver telling
|
|
|
|
|
us they got it.
|
|
|
|
|
|
|
|
|
|
(*) max_call_lifetime
|
|
|
|
|
|
|
|
|
|
The maximum amount of time in seconds that a call may be in progress
|
|
|
|
|
before we preemptively kill it.
|
|
|
|
|
|
|
|
|
|
(*) dead_call_expiry
|
|
|
|
|
|
|
|
|
|
The amount of time in seconds before we remove a dead call from the call
|
|
|
|
|
list. Dead calls are kept around for a little while for the purpose of
|
|
|
|
|
repeating ACK and ABORT packets.
|
|
|
|
|
|
|
|
|
|
(*) connection_expiry
|
|
|
|
|
|
|
|
|
|
The amount of time in seconds after a connection was last used before we
|
|
|
|
|
remove it from the connection list. Whilst a connection is in existence,
|
|
|
|
|
it serves as a placeholder for negotiated security; when it is deleted,
|
|
|
|
|
the security must be renegotiated.
|
|
|
|
|
|
|
|
|
|
(*) transport_expiry
|
|
|
|
|
|
|
|
|
|
The amount of time in seconds after a transport was last used before we
|
|
|
|
|
remove it from the transport list. Whilst a transport is in existence, it
|
|
|
|
|
serves to anchor the peer data and keeps the connection ID counter.
|
2014-02-08 02:10:30 +08:00
|
|
|
|
|
|
|
|
(*) rxrpc_rx_window_size
|
|
|
|
|
|
|
|
|
|
The size of the receive window in packets. This is the maximum number of
|
|
|
|
|
unconsumed received packets we're willing to hold in memory for any
|
|
|
|
|
particular call.
|
|
|
|
|
|
|
|
|
|
(*) rxrpc_rx_mtu
|
|
|
|
|
|
|
|
|
|
The maximum packet MTU size that we're willing to receive in bytes. This
|
|
|
|
|
indicates to the peer whether we're willing to accept jumbo packets.
|
|
|
|
|
|
|
|
|
|
(*) rxrpc_rx_jumbo_max
|
|
|
|
|
|
|
|
|
|
The maximum number of packets that we're willing to accept in a jumbo
|
|
|
|
|
packet. Non-terminal packets in a jumbo packet must contain a four byte
|
|
|
|
|
header plus exactly 1412 bytes of data. The terminal packet must contain
|
|
|
|
|
a four byte header plus any amount of data. In any event, a jumbo packet
|
|
|
|
|
may not exceed rxrpc_rx_mtu in size.
|
