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linux-next/include/rxrpc/packet.h
David Howells 4722974d90 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 14:30:49 +01:00

236 lines
9.3 KiB
C

/* packet.h: Rx packet layout and definitions
*
* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _LINUX_RXRPC_PACKET_H
#define _LINUX_RXRPC_PACKET_H
typedef u32 rxrpc_seq_t; /* Rx message sequence number */
typedef u32 rxrpc_serial_t; /* Rx message serial number */
typedef __be32 rxrpc_seq_net_t; /* on-the-wire Rx message sequence number */
typedef __be32 rxrpc_serial_net_t; /* on-the-wire Rx message serial number */
/*****************************************************************************/
/*
* on-the-wire Rx packet header
* - all multibyte fields should be in network byte order
*/
struct rxrpc_wire_header {
__be32 epoch; /* client boot timestamp */
#define RXRPC_RANDOM_EPOCH 0x80000000 /* Random if set, date-based if not */
__be32 cid; /* connection and channel ID */
#define RXRPC_MAXCALLS 4 /* max active calls per conn */
#define RXRPC_CHANNELMASK (RXRPC_MAXCALLS-1) /* mask for channel ID */
#define RXRPC_CIDMASK (~RXRPC_CHANNELMASK) /* mask for connection ID */
#define RXRPC_CIDSHIFT ilog2(RXRPC_MAXCALLS) /* shift for connection ID */
#define RXRPC_CID_INC (1 << RXRPC_CIDSHIFT) /* connection ID increment */
__be32 callNumber; /* call ID (0 for connection-level packets) */
__be32 seq; /* sequence number of pkt in call stream */
__be32 serial; /* serial number of pkt sent to network */
uint8_t type; /* packet type */
#define RXRPC_PACKET_TYPE_DATA 1 /* data */
#define RXRPC_PACKET_TYPE_ACK 2 /* ACK */
#define RXRPC_PACKET_TYPE_BUSY 3 /* call reject */
#define RXRPC_PACKET_TYPE_ABORT 4 /* call/connection abort */
#define RXRPC_PACKET_TYPE_ACKALL 5 /* ACK all outstanding packets on call */
#define RXRPC_PACKET_TYPE_CHALLENGE 6 /* connection security challenge (SRVR->CLNT) */
#define RXRPC_PACKET_TYPE_RESPONSE 7 /* connection secutity response (CLNT->SRVR) */
#define RXRPC_PACKET_TYPE_DEBUG 8 /* debug info request */
#define RXRPC_PACKET_TYPE_VERSION 13 /* version string request */
#define RXRPC_N_PACKET_TYPES 14 /* number of packet types (incl type 0) */
uint8_t flags; /* packet flags */
#define RXRPC_CLIENT_INITIATED 0x01 /* signifies a packet generated by a client */
#define RXRPC_REQUEST_ACK 0x02 /* request an unconditional ACK of this packet */
#define RXRPC_LAST_PACKET 0x04 /* the last packet from this side for this call */
#define RXRPC_MORE_PACKETS 0x08 /* more packets to come */
#define RXRPC_JUMBO_PACKET 0x20 /* [DATA] this is a jumbo packet */
#define RXRPC_SLOW_START_OK 0x20 /* [ACK] slow start supported */
uint8_t userStatus; /* app-layer defined status */
#define RXRPC_USERSTATUS_SERVICE_UPGRADE 0x01 /* AuriStor service upgrade request */
uint8_t securityIndex; /* security protocol ID */
union {
__be16 _rsvd; /* reserved */
__be16 cksum; /* kerberos security checksum */
};
__be16 serviceId; /* service ID */
} __packed;
#define RXRPC_SUPPORTED_PACKET_TYPES ( \
(1 << RXRPC_PACKET_TYPE_DATA) | \
(1 << RXRPC_PACKET_TYPE_ACK) | \
(1 << RXRPC_PACKET_TYPE_BUSY) | \
(1 << RXRPC_PACKET_TYPE_ABORT) | \
(1 << RXRPC_PACKET_TYPE_ACKALL) | \
(1 << RXRPC_PACKET_TYPE_CHALLENGE) | \
(1 << RXRPC_PACKET_TYPE_RESPONSE) | \
/*(1 << RXRPC_PACKET_TYPE_DEBUG) | */ \
(1 << RXRPC_PACKET_TYPE_VERSION))
/*****************************************************************************/
/*
* jumbo packet secondary header
* - can be mapped to read header by:
* - new_serial = serial + 1
* - new_seq = seq + 1
* - new_flags = j_flags
* - new__rsvd = j__rsvd
* - duplicating all other fields
*/
struct rxrpc_jumbo_header {
uint8_t flags; /* packet flags (as per rxrpc_header) */
uint8_t pad;
union {
__be16 _rsvd; /* reserved */
__be16 cksum; /* kerberos security checksum */
};
};
#define RXRPC_JUMBO_DATALEN 1412 /* non-terminal jumbo packet data length */
#define RXRPC_JUMBO_SUBPKTLEN (RXRPC_JUMBO_DATALEN + sizeof(struct rxrpc_jumbo_header))
/*****************************************************************************/
/*
* on-the-wire Rx ACK packet data payload
* - all multibyte fields should be in network byte order
*/
struct rxrpc_ackpacket {
__be16 bufferSpace; /* number of packet buffers available */
__be16 maxSkew; /* diff between serno being ACK'd and highest serial no
* received */
__be32 firstPacket; /* sequence no of first ACK'd packet in attached list */
__be32 previousPacket; /* sequence no of previous packet received */
__be32 serial; /* serial no of packet that prompted this ACK */
uint8_t reason; /* reason for ACK */
#define RXRPC_ACK_REQUESTED 1 /* ACK was requested on packet */
#define RXRPC_ACK_DUPLICATE 2 /* duplicate packet received */
#define RXRPC_ACK_OUT_OF_SEQUENCE 3 /* out of sequence packet received */
#define RXRPC_ACK_EXCEEDS_WINDOW 4 /* packet received beyond end of ACK window */
#define RXRPC_ACK_NOSPACE 5 /* packet discarded due to lack of buffer space */
#define RXRPC_ACK_PING 6 /* keep alive ACK */
#define RXRPC_ACK_PING_RESPONSE 7 /* response to RXRPC_ACK_PING */
#define RXRPC_ACK_DELAY 8 /* nothing happened since received packet */
#define RXRPC_ACK_IDLE 9 /* ACK due to fully received ACK window */
#define RXRPC_ACK__INVALID 10 /* Representation of invalid ACK reason */
uint8_t nAcks; /* number of ACKs */
#define RXRPC_MAXACKS 255
uint8_t acks[0]; /* list of ACK/NAKs */
#define RXRPC_ACK_TYPE_NACK 0
#define RXRPC_ACK_TYPE_ACK 1
} __packed;
/* Some ACKs refer to specific packets and some are general and can be updated. */
#define RXRPC_ACK_UPDATEABLE ((1 << RXRPC_ACK_REQUESTED) | \
(1 << RXRPC_ACK_PING_RESPONSE) | \
(1 << RXRPC_ACK_DELAY) | \
(1 << RXRPC_ACK_IDLE))
/*
* ACK packets can have a further piece of information tagged on the end
*/
struct rxrpc_ackinfo {
__be32 rxMTU; /* maximum Rx MTU size (bytes) [AFS 3.3] */
__be32 maxMTU; /* maximum interface MTU size (bytes) [AFS 3.3] */
__be32 rwind; /* Rx window size (packets) [AFS 3.4] */
__be32 jumbo_max; /* max packets to stick into a jumbo packet [AFS 3.5] */
};
/*****************************************************************************/
/*
* Kerberos security type-2 challenge packet
*/
struct rxkad_challenge {
__be32 version; /* version of this challenge type */
__be32 nonce; /* encrypted random number */
__be32 min_level; /* minimum security level */
__be32 __padding; /* padding to 8-byte boundary */
} __packed;
/*****************************************************************************/
/*
* Kerberos security type-2 response packet
*/
struct rxkad_response {
__be32 version; /* version of this response type */
__be32 __pad;
/* encrypted bit of the response */
struct {
__be32 epoch; /* current epoch */
__be32 cid; /* parent connection ID */
__be32 checksum; /* checksum */
__be32 securityIndex; /* security type */
__be32 call_id[4]; /* encrypted call IDs */
__be32 inc_nonce; /* challenge nonce + 1 */
__be32 level; /* desired level */
} encrypted;
__be32 kvno; /* Kerberos key version number */
__be32 ticket_len; /* Kerberos ticket length */
} __packed;
/*****************************************************************************/
/*
* RxRPC-level abort codes
*/
#define RX_CALL_DEAD -1 /* call/conn has been inactive and is shut down */
#define RX_INVALID_OPERATION -2 /* invalid operation requested / attempted */
#define RX_CALL_TIMEOUT -3 /* call timeout exceeded */
#define RX_EOF -4 /* unexpected end of data on read op */
#define RX_PROTOCOL_ERROR -5 /* low-level protocol error */
#define RX_USER_ABORT -6 /* generic user abort */
#define RX_ADDRINUSE -7 /* UDP port in use */
#define RX_DEBUGI_BADTYPE -8 /* bad debugging packet type */
/*
* (un)marshalling abort codes (rxgen)
*/
#define RXGEN_CC_MARSHAL -450
#define RXGEN_CC_UNMARSHAL -451
#define RXGEN_SS_MARSHAL -452
#define RXGEN_SS_UNMARSHAL -453
#define RXGEN_DECODE -454
#define RXGEN_OPCODE -455
#define RXGEN_SS_XDRFREE -456
#define RXGEN_CC_XDRFREE -457
/*
* Rx kerberos security abort codes
* - unfortunately we have no generalised security abort codes to say things
* like "unsupported security", so we have to use these instead and hope the
* other side understands
*/
#define RXKADINCONSISTENCY 19270400 /* security module structure inconsistent */
#define RXKADPACKETSHORT 19270401 /* packet too short for security challenge */
#define RXKADLEVELFAIL 19270402 /* security level negotiation failed */
#define RXKADTICKETLEN 19270403 /* ticket length too short or too long */
#define RXKADOUTOFSEQUENCE 19270404 /* packet had bad sequence number */
#define RXKADNOAUTH 19270405 /* caller not authorised */
#define RXKADBADKEY 19270406 /* illegal key: bad parity or weak */
#define RXKADBADTICKET 19270407 /* security object was passed a bad ticket */
#define RXKADUNKNOWNKEY 19270408 /* ticket contained unknown key version number */
#define RXKADEXPIRED 19270409 /* authentication expired */
#define RXKADSEALEDINCON 19270410 /* sealed data inconsistent */
#define RXKADDATALEN 19270411 /* user data too long */
#define RXKADILLEGALLEVEL 19270412 /* caller not authorised to use encrypted conns */
#endif /* _LINUX_RXRPC_PACKET_H */