diff options
| author | Erich E. Hoover <ehoover@mines.edu> | 2012-02-08 09:11:07 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-02-08 15:52:45 -0500 |
| commit | 76e21053b5bf33a07c76f99d27a74238310e3c71 (patch) | |
| tree | 70ac2a67be8f19da96896950447567e156975149 /net/ipv4/ping.c | |
| parent | 43480aecb1f538d4f6dd8b2c5d2b71fb98659072 (diff) | |
| download | lwn-76e21053b5bf33a07c76f99d27a74238310e3c71.tar.gz lwn-76e21053b5bf33a07c76f99d27a74238310e3c71.zip | |
ipv4: Implement IP_UNICAST_IF socket option.
The IP_UNICAST_IF feature is needed by the Wine project. This patch
implements the feature by setting the outgoing interface in a similar
fashion to that of IP_MULTICAST_IF. A separate option is needed to
handle this feature since the existing options do not provide all of
the characteristics required by IP_UNICAST_IF, a summary is provided
below.
SO_BINDTODEVICE:
* SO_BINDTODEVICE requires administrative privileges, IP_UNICAST_IF
does not. From reading some old mailing list articles my
understanding is that SO_BINDTODEVICE requires administrative
privileges because it can override the administrator's routing
settings.
* The SO_BINDTODEVICE option restricts both outbound and inbound
traffic, IP_UNICAST_IF only impacts outbound traffic.
IP_PKTINFO:
* Since IP_PKTINFO and IP_UNICAST_IF are independent options,
implementing IP_UNICAST_IF with IP_PKTINFO will likely break some
applications.
* Implementing IP_UNICAST_IF on top of IP_PKTINFO significantly
complicates the Wine codebase and reduces the socket performance
(doing this requires a lot of extra communication between the
"server" and "user" layers).
bind():
* bind() does not work on broadcast packets, IP_UNICAST_IF is
specifically intended to work with broadcast packets.
* Like SO_BINDTODEVICE, bind() restricts both outbound and inbound
traffic.
Signed-off-by: Erich E. Hoover <ehoover@mines.edu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ping.c')
| -rw-r--r-- | net/ipv4/ping.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index aea5a199c37a..cfc82cf339f6 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -556,7 +556,8 @@ static int ping_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, ipc.oif = inet->mc_index; if (!saddr) saddr = inet->mc_addr; - } + } else if (!ipc.oif) + ipc.oif = inet->uc_index; flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, sk->sk_protocol, |