net: Convert protocol error handlers from void to int

We'll need this to handle ICMP errors for tunnels without a sending socket
(i.e. FoU and GUE). There, we might have to look up different types of IP
tunnels, registered as network protocols, before we get a match, so we
want this for the error handlers of IPPROTO_IPIP and IPPROTO_IPV6 in both
inet_protos and inet6_protos. These error codes will be used in the next
patch.

For consistency, return sensible error codes in protocol error handlers
whenever handlers can't handle errors because, even if valid, they don't
match a protocol or any of its states.

This has no effect on existing error handling paths.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 5 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 03e6b7a2bc53..a3f559162521 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -349,7 +349,7 @@ static void tcp_v6_mtu_reduced(struct sock *sk)
         }
 }
 
-static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                 u8 type, u8 code, int offset, __be32 info)
 {
         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
@@ -371,17 +371,19 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
         if (!sk) {
                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
                                   ICMP6_MIB_INERRORS);
-                return;
+                return -ENOENT;
         }
 
         if (sk->sk_state == TCP_TIME_WAIT) {
                 inet_twsk_put(inet_twsk(sk));
-                return;
+                return 0;
         }
         seq = ntohl(th->seq);
         fatal = icmpv6_err_convert(type, code, &err);
-        if (sk->sk_state == TCP_NEW_SYN_RECV)
-                return tcp_req_err(sk, seq, fatal);
+        if (sk->sk_state == TCP_NEW_SYN_RECV) {
+                tcp_req_err(sk, seq, fatal);
+                return 0;
+        }
 
         bh_lock_sock(sk);
         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
@@ -467,6 +469,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 out:
         bh_unlock_sock(sk);
         sock_put(sk);
+        return 0;
 }