IPv4: early demux can return an error code

Currently no error is emitted, but this infrastructure will
used by the next patch to allow source address validation
for mcast sockets.
Since early demux can do a route lookup and an ipv4 route
lookup can return an error code this is consistent with the
current ipv4 route infrastructure.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d9416b5162bc..85164d4d3e53 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1503,23 +1503,23 @@ csum_err:
 }
 EXPORT_SYMBOL(tcp_v4_do_rcv);
 
-void tcp_v4_early_demux(struct sk_buff *skb)
+int tcp_v4_early_demux(struct sk_buff *skb)
 {
         const struct iphdr *iph;
         const struct tcphdr *th;
         struct sock *sk;
 
         if (skb->pkt_type != PACKET_HOST)
-                return;
+                return 0;
 
         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
-                return;
+                return 0;
 
         iph = ip_hdr(skb);
         th = tcp_hdr(skb);
 
         if (th->doff < sizeof(struct tcphdr) / 4)
-                return;
+                return 0;
 
         sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
                                        iph->saddr, th->source,
@@ -1538,6 +1538,7 @@ void tcp_v4_early_demux(struct sk_buff *skb)
                                 skb_dst_set_noref(skb, dst);
                 }
         }
+        return 0;
 }
 
 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)