This patch adds 4 new sample fetches to get the source and the destination
info (ip address and port) of the backend connection :
* bc_dst : Returns the destination address of the backend connection
* bc_dst_port : Returns the destination port of the backend connection
* bc_src : Returns the source address of the backend connection
* bc_src_port : Returns the source port of the backend connection
The configuration manual was updated accordingly.
Historically we've used SOL_IP/SOL_IPV6/SOL_TCP everywhere as the socket
level value in getsockopt() and setsockopt() but as we've seen over time
it regularly broke the build and required to have them defined to their
IPPROTO_* equivalent. The Linux ip(7) man page says:
Using the SOL_IP socket options level isn't portable; BSD-based
stacks use the IPPROTO_IP level.
And it indeed looks like a pure linuxism inherited from old examples and
documentation. strace also reports SOL_* instead of IPPROTO_*, which does
not help... A check to linux/in.h shows they have the same values. Only
SOL_SOCKET and other non-IP values make sense since there is no IPPROTO
equivalent.
Let's get rid of this annoying confusion by removing all redefinitions of
SOL_IP/IPV6/TCP and using IPPROTO_* instead, just like any other operating
system. This also removes duplicated tests for the same value.
Note that this should not result in exposing syscalls to other OSes
as the only ones that were still conditionned to SOL_IPV6 were for
IPV6_UNICAST_HOPS which already had an IPPROTO_IPV6 equivalent, and
IPV6_TRANSPARENT which is Linux-specific.
Some socket settings used to be retrieved via the listener and the
bind_conf. Now instead we use the receiver and its settings whenever
appropriate. This will simplify the removal of the dependency on the
listener.
The netns is common to all listeners/receivers and is used to bind the
listening socket so it must be in the receiver settings and not in the
listener. This removes some yet another set of unnecessary loops.
Let's continue the cleanup and get rid of all sample fetch functions
from proto_tcp.c. They're now moved to tcp_sample.c, just as was done
for ssl before 2.2 release. Nothing has changed beyond this.
