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/ip_sockglue.c | |
| parent | 43480aecb1f538d4f6dd8b2c5d2b71fb98659072 (diff) | |
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/ip_sockglue.c')
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 8aa87c19fa0..9125529dab9 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -469,6 +469,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, (1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) | (1<<IP_PASSSEC) | (1<<IP_TRANSPARENT) | (1<<IP_MINTTL) | (1<<IP_NODEFRAG))) || + optname == IP_UNICAST_IF || optname == IP_MULTICAST_TTL || optname == IP_MULTICAST_ALL || optname == IP_MULTICAST_LOOP || @@ -628,6 +629,35 @@ static int do_ip_setsockopt(struct sock *sk, int level, goto e_inval; inet->mc_loop = !!val; break; + case IP_UNICAST_IF: + { + struct net_device *dev = NULL; + int ifindex; + + if (optlen != sizeof(int)) + goto e_inval; + + ifindex = (__force int)ntohl((__force __be32)val); + if (ifindex == 0) { + inet->uc_index = 0; + err = 0; + break; + } + + dev = dev_get_by_index(sock_net(sk), ifindex); + err = -EADDRNOTAVAIL; + if (!dev) + break; + dev_put(dev); + + err = -EINVAL; + if (sk->sk_bound_dev_if) + break; + + inet->uc_index = ifindex; + err = 0; + break; + } case IP_MULTICAST_IF: { struct ip_mreqn mreq; @@ -1178,6 +1208,9 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname, case IP_MULTICAST_LOOP: val = inet->mc_loop; break; + case IP_UNICAST_IF: + val = (__force int)htonl((__u32) inet->uc_index); + break; case IP_MULTICAST_IF: { struct in_addr addr; |