MFC: r292980

Clean up unused-but-set-variable spotted by gcc4.9.

Reviewed by: ngie
Approved by: rodrigc (mentor)
Sponsored by: gandi.net
Differential Revision: https://reviews.freebsd.org/D4774

MFC r288575:

Add IFCAP_LINKSTATE support.

MFC 287607:

- Remove GIF_{SEND,ACCEPT}_REVETHIP.
- Simplify EADDRNOTAVAIL and EAFNOSUPPORT conditions.

MFC r282809:
Add new socket ioctls SIOC[SG]TUNFIB to set FIB number of encapsulated
packets on tunnel interfaces. Add support of these ioctls to gre(4),
gif(4) and me(4) interfaces. For incoming packets M_SETFIB() should use
if_fib value from ifnet structure, use proper value in gre(4) and me(4).

Differential Revision: https://reviews.freebsd.org/D2462

MFC r276148:
Remove in_gif.h and in6_gif.h files. They only contain function
declarations used by gif(4). Instead declare these functions in C files.
Also make some variables static.

MFC r276215:
Extern declarations in C files loses compile-time checking that
the functions' calls match their definitions. Move them to header files.

MFC r276901:
Move the recursion detection code into separate function
gif_check_nesting(). Also make MTAG_GIF definition private to if_gif.c.

MFC r276907:
Restore Ethernet-within-IP Encapsulation support that was broken after
r273087. Move all checks from gif_output() into gif_transmit(). Previously
they were checked always, because if_start always called gif_output.
Now gif_transmit() can be called directly from if_bridge() code and we need
do checks here.

PR: 196646

MFC r273087 (with modifications):
Overhaul if_gif(4):
o convert to if_transmit;
o use rmlock to protect access to gif_softc;
o use sx lock to protect from concurrent ioctls;
o remove a lot of unneeded and duplicated code;
o remove cached route support (it won't work with concurrent io);
o style fixes.

MFC r273090:
Move memset under ifdef INET6.

MFC r273091:
Add more ifdefs. SIOC*_IN6 are defined only with INET6.

MFC r273121:
Add inet/inet6 to the dependency list. Without them if_gif is useless.

MFC r273209 by bz:
After r273087,r273090,r273091,r273121 changes to gif(4) try to fix
NOIP builds for real.

MFC r273587:
Remove redundant check and m_pullup() call.

MFC r271917 by hrs:
Virtualize interface cloner for gif(4). This fixes a panic when destroying
a vnet jail which has a gif(4) interface.

MFC r258167:
ANSIfy function defintions.

MFC r272770:
When tunneling interface is going to insert mbuf into netisr queue after stripping
outer header, consider it as new packet and clear the protocols flags.

This fixes problems when IPSEC traffic goes through various tunnels and router
doesn't send ICMP/ICMPv6 errors.

PR: 174602
Sponsored by: Yandex LLC

MFC 287607:

- Remove GIF_{SEND,ACCEPT}_REVETHIP.
- Simplify EADDRNOTAVAIL and EAFNOSUPPORT conditions.

MFC r282809:
Add new socket ioctls SIOC[SG]TUNFIB to set FIB number of encapsulated
packets on tunnel interfaces. Add support of these ioctls to gre(4),
gif(4) and me(4) interfaces. For incoming packets M_SETFIB() should use
if_fib value from ifnet structure, use proper value in gre(4) and me(4).

Differential Revision: https://reviews.freebsd.org/D2462

MFC r276148:
Remove in_gif.h and in6_gif.h files. They only contain function
declarations used by gif(4). Instead declare these functions in C files.
Also make some variables static.

MFC r276215:
Extern declarations in C files loses compile-time checking that
the functions' calls match their definitions. Move them to header files.

MFC r276901:
Move the recursion detection code into separate function
gif_check_nesting(). Also make MTAG_GIF definition private to if_gif.c.

MFC r276907:
Restore Ethernet-within-IP Encapsulation support that was broken after
r273087. Move all checks from gif_output() into gif_transmit(). Previously
they were checked always, because if_start always called gif_output.
Now gif_transmit() can be called directly from if_bridge() code and we need
do checks here.

PR: 196646

MFC r273087 (with modifications):
Overhaul if_gif(4):
o convert to if_transmit;
o use rmlock to protect access to gif_softc;
o use sx lock to protect from concurrent ioctls;
o remove a lot of unneeded and duplicated code;
o remove cached route support (it won't work with concurrent io);
o style fixes.

MFC r273090:
Move memset under ifdef INET6.

MFC r273091:
Add more ifdefs. SIOC*_IN6 are defined only with INET6.

MFC r273121:
Add inet/inet6 to the dependency list. Without them if_gif is useless.

MFC r273209 by bz:
After r273087,r273090,r273091,r273121 changes to gif(4) try to fix
NOIP builds for real.

MFC r273587:
Remove redundant check and m_pullup() call.

MFC r271917 by hrs:
Virtualize interface cloner for gif(4). This fixes a panic when destroying
a vnet jail which has a gif(4) interface.

MFC r258167:
ANSIfy function defintions.

MFC r272770:
When tunneling interface is going to insert mbuf into netisr queue after stripping
outer header, consider it as new packet and clear the protocols flags.

This fixes problems when IPSEC traffic goes through various tunnels and router
doesn't send ICMP/ICMPv6 errors.

PR: 174602
Sponsored by: Yandex LLC