ipv4: sendto/hdrincl: don't use destination address found in header

[ Upstream commit c27c9322d015dc1d9dfdf31724fca71c0476c4d1 ]

ipv4: raw_sendmsg: don't use header's destination address

A sendto() regression was bisected and found to start with commit
f8126f1d5136be1 (ipv4: Adjust semantics of rt->rt_gateway.)

The problem is that it tries to ARP-lookup the constructed packet's
destination address rather than the explicitly provided address.

Fix this using FLOWI_FLAG_KNOWN_NH so that given nexthop is used.

cf. commit 2ad5b9e4bd314fc685086b99e90e5de3bc59e26b

Reported-by: Chris Clark <chris.clark@alcatel-lucent.com>
Bisected-by: Chris Clark <chris.clark@alcatel-lucent.com>
Tested-by: Chris Clark <chris.clark@alcatel-lucent.com>
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Chris Clark <chris.clark@alcatel-lucent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index dd44e0ab600c..61e60d67adca 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -571,7 +571,8 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
         flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
                            RT_SCOPE_UNIVERSE,
                            inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
-                           inet_sk_flowi_flags(sk) | FLOWI_FLAG_CAN_SLEEP,
+                           inet_sk_flowi_flags(sk) | FLOWI_FLAG_CAN_SLEEP |
+                            (inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0),
                            daddr, saddr, 0, 0);
 
         if (!inet->hdrincl) {