2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-16 09:13:55 +08:00
linux-next/net/Kconfig
Johannes Berg 1dacc76d00 net/compat/wext: send different messages to compat tasks
Wireless extensions have the unfortunate problem that events
are multicast netlink messages, and are not independent of
pointer size. Thus, currently 32-bit tasks on 64-bit platforms
cannot properly receive events and fail with all kinds of
strange problems, for instance wpa_supplicant never notices
disassociations, due to the way the 64-bit event looks (to a
32-bit process), the fact that the address is all zeroes is
lost, it thinks instead it is 00:00:00:00:01:00.

The same problem existed with the ioctls, until David Miller
fixed those some time ago in an heroic effort.

A different problem caused by this is that we cannot send the
ASSOCREQIE/ASSOCRESPIE events because sending them causes a
32-bit wpa_supplicant on a 64-bit system to overwrite its
internal information, which is worse than it not getting the
information at all -- so we currently resort to sending a
custom string event that it then parses. This, however, has a
severe size limitation we are frequently hitting with modern
access points; this limitation would can be lifted after this
patch by sending the correct binary, not custom, event.

A similar problem apparently happens for some other netlink
users on x86_64 with 32-bit tasks due to the alignment for
64-bit quantities.

In order to fix these problems, I have implemented a way to
send compat messages to tasks. When sending an event, we send
the non-compat event data together with a compat event data in
skb_shinfo(main_skb)->frag_list. Then, when the event is read
from the socket, the netlink code makes sure to pass out only
the skb that is compatible with the task. This approach was
suggested by David Miller, my original approach required
always sending two skbs but that had various small problems.

To determine whether compat is needed or not, I have used the
MSG_CMSG_COMPAT flag, and adjusted the call path for recv and
recvfrom to include it, even if those calls do not have a cmsg
parameter.

I have not solved one small part of the problem, and I don't
think it is necessary to: if a 32-bit application uses read()
rather than any form of recvmsg() it will still get the wrong
(64-bit) event. However, neither do applications actually do
this, nor would it be a regression.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-07-15 08:53:39 -07:00

280 lines
9.3 KiB
Plaintext

#
# Network configuration
#
menuconfig NET
bool "Networking support"
select NLATTR
---help---
Unless you really know what you are doing, you should say Y here.
The reason is that some programs need kernel networking support even
when running on a stand-alone machine that isn't connected to any
other computer.
If you are upgrading from an older kernel, you
should consider updating your networking tools too because changes
in the kernel and the tools often go hand in hand. The tools are
contained in the package net-tools, the location and version number
of which are given in <file:Documentation/Changes>.
For a general introduction to Linux networking, it is highly
recommended to read the NET-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
if NET
config WANT_COMPAT_NETLINK_MESSAGES
bool
help
This option can be selected by other options that need compat
netlink messages.
config COMPAT_NETLINK_MESSAGES
def_bool y
depends on COMPAT
depends on WIRELESS_EXT || WANT_COMPAT_NETLINK_MESSAGES
help
This option makes it possible to send different netlink messages
to tasks depending on whether the task is a compat task or not. To
achieve this, you need to set skb_shinfo(skb)->frag_list to the
compat skb before sending the skb, the netlink code will sort out
which message to actually pass to the task.
Newly written code should NEVER need this option but do
compat-independent messages instead!
menu "Networking options"
source "net/packet/Kconfig"
source "net/unix/Kconfig"
source "net/xfrm/Kconfig"
source "net/iucv/Kconfig"
config INET
bool "TCP/IP networking"
---help---
These are the protocols used on the Internet and on most local
Ethernets. It is highly recommended to say Y here (this will enlarge
your kernel by about 400 KB), since some programs (e.g. the X window
system) use TCP/IP even if your machine is not connected to any
other computer. You will get the so-called loopback device which
allows you to ping yourself (great fun, that!).
For an excellent introduction to Linux networking, please read the
Linux Networking HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
If you say Y here and also to "/proc file system support" and
"Sysctl support" below, you can change various aspects of the
behavior of the TCP/IP code by writing to the (virtual) files in
/proc/sys/net/ipv4/*; the options are explained in the file
<file:Documentation/networking/ip-sysctl.txt>.
Short answer: say Y.
if INET
source "net/ipv4/Kconfig"
source "net/ipv6/Kconfig"
source "net/netlabel/Kconfig"
endif # if INET
config NETWORK_SECMARK
bool "Security Marking"
help
This enables security marking of network packets, similar
to nfmark, but designated for security purposes.
If you are unsure how to answer this question, answer N.
menuconfig NETFILTER
bool "Network packet filtering framework (Netfilter)"
---help---
Netfilter is a framework for filtering and mangling network packets
that pass through your Linux box.
The most common use of packet filtering is to run your Linux box as
a firewall protecting a local network from the Internet. The type of
firewall provided by this kernel support is called a "packet
filter", which means that it can reject individual network packets
based on type, source, destination etc. The other kind of firewall,
a "proxy-based" one, is more secure but more intrusive and more
bothersome to set up; it inspects the network traffic much more
closely, modifies it and has knowledge about the higher level
protocols, which a packet filter lacks. Moreover, proxy-based
firewalls often require changes to the programs running on the local
clients. Proxy-based firewalls don't need support by the kernel, but
they are often combined with a packet filter, which only works if
you say Y here.
You should also say Y here if you intend to use your Linux box as
the gateway to the Internet for a local network of machines without
globally valid IP addresses. This is called "masquerading": if one
of the computers on your local network wants to send something to
the outside, your box can "masquerade" as that computer, i.e. it
forwards the traffic to the intended outside destination, but
modifies the packets to make it look like they came from the
firewall box itself. It works both ways: if the outside host
replies, the Linux box will silently forward the traffic to the
correct local computer. This way, the computers on your local net
are completely invisible to the outside world, even though they can
reach the outside and can receive replies. It is even possible to
run globally visible servers from within a masqueraded local network
using a mechanism called portforwarding. Masquerading is also often
called NAT (Network Address Translation).
Another use of Netfilter is in transparent proxying: if a machine on
the local network tries to connect to an outside host, your Linux
box can transparently forward the traffic to a local server,
typically a caching proxy server.
Yet another use of Netfilter is building a bridging firewall. Using
a bridge with Network packet filtering enabled makes iptables "see"
the bridged traffic. For filtering on the lower network and Ethernet
protocols over the bridge, use ebtables (under bridge netfilter
configuration).
Various modules exist for netfilter which replace the previous
masquerading (ipmasqadm), packet filtering (ipchains), transparent
proxying, and portforwarding mechanisms. Please see
<file:Documentation/Changes> under "iptables" for the location of
these packages.
if NETFILTER
config NETFILTER_DEBUG
bool "Network packet filtering debugging"
depends on NETFILTER
help
You can say Y here if you want to get additional messages useful in
debugging the netfilter code.
config NETFILTER_ADVANCED
bool "Advanced netfilter configuration"
depends on NETFILTER
default y
help
If you say Y here you can select between all the netfilter modules.
If you say N the more unusual ones will not be shown and the
basic ones needed by most people will default to 'M'.
If unsure, say Y.
config BRIDGE_NETFILTER
bool "Bridged IP/ARP packets filtering"
depends on BRIDGE && NETFILTER && INET
depends on NETFILTER_ADVANCED
default y
---help---
Enabling this option will let arptables resp. iptables see bridged
ARP resp. IP traffic. If you want a bridging firewall, you probably
want this option enabled.
Enabling or disabling this option doesn't enable or disable
ebtables.
If unsure, say N.
source "net/netfilter/Kconfig"
source "net/ipv4/netfilter/Kconfig"
source "net/ipv6/netfilter/Kconfig"
source "net/decnet/netfilter/Kconfig"
source "net/bridge/netfilter/Kconfig"
endif
source "net/dccp/Kconfig"
source "net/sctp/Kconfig"
source "net/rds/Kconfig"
source "net/tipc/Kconfig"
source "net/atm/Kconfig"
source "net/802/Kconfig"
source "net/bridge/Kconfig"
source "net/dsa/Kconfig"
source "net/8021q/Kconfig"
source "net/decnet/Kconfig"
source "net/llc/Kconfig"
source "net/ipx/Kconfig"
source "drivers/net/appletalk/Kconfig"
source "net/x25/Kconfig"
source "net/lapb/Kconfig"
source "net/econet/Kconfig"
source "net/wanrouter/Kconfig"
source "net/phonet/Kconfig"
source "net/ieee802154/Kconfig"
source "net/sched/Kconfig"
source "net/dcb/Kconfig"
menu "Network testing"
config NET_PKTGEN
tristate "Packet Generator (USE WITH CAUTION)"
depends on PROC_FS
---help---
This module will inject preconfigured packets, at a configurable
rate, out of a given interface. It is used for network interface
stress testing and performance analysis. If you don't understand
what was just said, you don't need it: say N.
Documentation on how to use the packet generator can be found
at <file:Documentation/networking/pktgen.txt>.
To compile this code as a module, choose M here: the
module will be called pktgen.
config NET_TCPPROBE
tristate "TCP connection probing"
depends on INET && EXPERIMENTAL && PROC_FS && KPROBES
---help---
This module allows for capturing the changes to TCP connection
state in response to incoming packets. It is used for debugging
TCP congestion avoidance modules. If you don't understand
what was just said, you don't need it: say N.
Documentation on how to use TCP connection probing can be found
at http://linux-net.osdl.org/index.php/TcpProbe
To compile this code as a module, choose M here: the
module will be called tcp_probe.
config NET_DROP_MONITOR
boolean "Network packet drop alerting service"
depends on INET && EXPERIMENTAL && TRACEPOINTS
---help---
This feature provides an alerting service to userspace in the
event that packets are discarded in the network stack. Alerts
are broadcast via netlink socket to any listening user space
process. If you don't need network drop alerts, or if you are ok
just checking the various proc files and other utilities for
drop statistics, say N here.
endmenu
endmenu
source "net/ax25/Kconfig"
source "net/can/Kconfig"
source "net/irda/Kconfig"
source "net/bluetooth/Kconfig"
source "net/rxrpc/Kconfig"
config FIB_RULES
bool
menuconfig WIRELESS
bool "Wireless"
depends on !S390
default y
if WIRELESS
source "net/wireless/Kconfig"
source "net/mac80211/Kconfig"
endif # WIRELESS
source "net/wimax/Kconfig"
source "net/rfkill/Kconfig"
source "net/9p/Kconfig"
endif # if NET