diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2025-06-09 07:39:33 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-20 18:30:39 +0200 |
| commit | 3aaa339f64d98fcb487ac788553c60ea40b65171 (patch) | |
| tree | 64624289b01645f7e587e0f6832d579a0bff30cd | |
| parent | 5c196b3c1222c6ad3f06bd5792864fdf715bf7b9 (diff) | |
uapi: in6: restore visibility of most IPv6 socket options
[ Upstream commit 31557b3487b349464daf42bc4366153743c1e727 ]
A decade ago commit 6d08acd2d32e ("in6: fix conflict with glibc")
hid the definitions of IPV6 options, because GCC was complaining
about duplicates. The commit did not list the warnings seen, but
trying to recreate them now I think they are (building iproute2):
In file included from ./include/uapi/rdma/rdma_user_cm.h:39,
from rdma.h:16,
from res.h:9,
from res-ctx.c:7:
../include/uapi/linux/in6.h:171:9: warning: ‘IPV6_ADD_MEMBERSHIP’ redefined
171 | #define IPV6_ADD_MEMBERSHIP 20
| ^~~~~~~~~~~~~~~~~~~
In file included from /usr/include/netinet/in.h:37,
from rdma.h:13:
/usr/include/bits/in.h:233:10: note: this is the location of the previous definition
233 | # define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
| ^~~~~~~~~~~~~~~~~~~
../include/uapi/linux/in6.h:172:9: warning: ‘IPV6_DROP_MEMBERSHIP’ redefined
172 | #define IPV6_DROP_MEMBERSHIP 21
| ^~~~~~~~~~~~~~~~~~~~
/usr/include/bits/in.h:234:10: note: this is the location of the previous definition
234 | # define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
| ^~~~~~~~~~~~~~~~~~~~
Compilers don't complain about redefinition if the defines
are identical, but here we have the kernel using the literal
value, and glibc using an indirection (defining to a name
of another define, with the same numerical value).
Problem is, the commit in question hid all the IPV6 socket
options, and glibc has a pretty sparse list. For instance
it lacks Flow Label related options. Willem called this out
in commit 3fb321fde22d ("selftests/net: ipv6 flowlabel"):
/* uapi/glibc weirdness may leave this undefined */
#ifndef IPV6_FLOWINFO
#define IPV6_FLOWINFO 11
#endif
More interestingly some applications (socat) use
a #ifdef IPV6_FLOWINFO to gate compilation of thier
rudimentary flow label support. (For added confusion
socat misspells it as IPV4_FLOWINFO in some places.)
Hide only the two defines we know glibc has a problem
with. If we discover more warnings we can hide more
but we should avoid covering the entire block of
defines for "IPV6 socket options".
Link: https://patch.msgid.link/20250609143933.1654417-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | include/uapi/linux/in6.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h index ff8d21f9e95b..5a47339ef7d7 100644 --- a/include/uapi/linux/in6.h +++ b/include/uapi/linux/in6.h @@ -152,7 +152,6 @@ struct in6_flowlabel_req { /* * IPV6 socket options */ -#if __UAPI_DEF_IPV6_OPTIONS #define IPV6_ADDRFORM 1 #define IPV6_2292PKTINFO 2 #define IPV6_2292HOPOPTS 3 @@ -169,8 +168,10 @@ struct in6_flowlabel_req { #define IPV6_MULTICAST_IF 17 #define IPV6_MULTICAST_HOPS 18 #define IPV6_MULTICAST_LOOP 19 +#if __UAPI_DEF_IPV6_OPTIONS #define IPV6_ADD_MEMBERSHIP 20 #define IPV6_DROP_MEMBERSHIP 21 +#endif #define IPV6_ROUTER_ALERT 22 #define IPV6_MTU_DISCOVER 23 #define IPV6_MTU 24 @@ -203,7 +204,6 @@ struct in6_flowlabel_req { #define IPV6_IPSEC_POLICY 34 #define IPV6_XFRM_POLICY 35 #define IPV6_HDRINCL 36 -#endif /* * Multicast: |