commit f5715aea4564f233767ea1d944b2637a5fd7cd2e
author KOVACS Krisztian <hidden@sch.bme.hu> Wed Oct 01 07:30:02 2008 -0700
committer David S. Miller <davem@davemloft.net> Wed Oct 01 07:30:02 2008 -0700
tree e74e56e56dff19940ba3a5002355ba1bfc73f573
parent a210d01ae3ee006b59e54e772a7f212486e0f021

ipv4: Implement IP_TRANSPARENT socket option

This patch introduces the IP_TRANSPARENT socket option: enabling that
will make the IPv4 routing omit the non-local source address check on
output. Setting IP_TRANSPARENT requires NET_ADMIN capability.

Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/inet_timewait_sock.c

diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 743f011..1c5fd38 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -126,6 +126,7 @@
 		tw->tw_reuse	    = sk->sk_reuse;
 		tw->tw_hash	    = sk->sk_hash;
 		tw->tw_ipv6only	    = 0;
+		tw->tw_transparent  = inet->transparent;
 		tw->tw_prot	    = sk->sk_prot_creator;
 		twsk_net_set(tw, hold_net(sock_net(sk)));
 		atomic_set(&tw->tw_refcnt, 1);

net/ipv4/ip_sockglue.c

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 105d92a..465abf0 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -419,7 +419,7 @@
 			     (1<<IP_TTL) | (1<<IP_HDRINCL) |
 			     (1<<IP_MTU_DISCOVER) | (1<<IP_RECVERR) |
 			     (1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) |
-			     (1<<IP_PASSSEC))) ||
+			     (1<<IP_PASSSEC) | (1<<IP_TRANSPARENT))) ||
 	    optname == IP_MULTICAST_TTL ||
 	    optname == IP_MULTICAST_LOOP) {
 		if (optlen >= sizeof(int)) {
@@ -878,6 +878,16 @@
 		err = xfrm_user_policy(sk, optname, optval, optlen);
 		break;
 
+	case IP_TRANSPARENT:
+		if (!capable(CAP_NET_ADMIN)) {
+			err = -EPERM;
+			break;
+		}
+		if (optlen < 1)
+			goto e_inval;
+		inet->transparent = !!val;
+		break;
+
 	default:
 		err = -ENOPROTOOPT;
 		break;
@@ -1130,6 +1140,9 @@
 	case IP_FREEBIND:
 		val = inet->freebind;
 		break;
+	case IP_TRANSPARENT:
+		val = inet->transparent;
+		break;
 	default:
 		release_sock(sk);
 		return -ENOPROTOOPT;