ipip: only increase err_count for some certain type icmp in ipip_err

t->err_count is used to count the link failure on tunnel and an err
will be reported to user socket in tx path if t->err_count is not 0.
udp socket could even return EHOSTUNREACH to users.

Since commit fd58156e456d ("IPIP: Use ip-tunneling code.") removed
the 'switch check' for icmp type in ipip_err(), err_count would be
increased by the icmp packet with ICMP_EXC_FRAGTIME code. an link
failure would be reported out due to this.

In Jianlin's case, when receiving ICMP_EXC_FRAGTIME a icmp packet,
udp netperf failed with the err:
  send_data: data send error: No route to host (errno 113)

We expect this error reported from tunnel to socket when receiving
some certain type icmp, but not ICMP_EXC_FRAGTIME, ICMP_SR_FAILED
or ICMP_PARAMETERPROB ones.

This patch is to bring 'switch check' for icmp type back to ipip_err
so that it only reports link failure for the right type icmp, just as
in ipgre_err() and ipip6_err().

Fixes: fd58156e456d ("IPIP: Use ip-tunneling code.")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index fb1ad22b5e292d5669c70b5640ad3207c353c6bb..cdd627355ed106ae8228ee4a995f5f3b4588a842 100644 (file)
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -128,43 +128,68 @@ static struct rtnl_link_ops ipip_link_ops __read_mostly;
 
 static int ipip_err(struct sk_buff *skb, u32 info)
 {
-
-/* All the routers (except for Linux) return only
-   8 bytes of packet payload. It means, that precise relaying of
-   ICMP in the real Internet is absolutely infeasible.
- */
+       /* All the routers (except for Linux) return only
+        * 8 bytes of packet payload. It means, that precise relaying of
+        * ICMP in the real Internet is absolutely infeasible.
+        */
        struct net *net = dev_net(skb->dev);
        struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
        const struct iphdr *iph = (const struct iphdr *)skb->data;
-       struct ip_tunnel *t;
-       int err;
        const int type = icmp_hdr(skb)->type;
        const int code = icmp_hdr(skb)->code;
+       struct ip_tunnel *t;
+       int err = 0;
+
+       switch (type) {
+       case ICMP_DEST_UNREACH:
+               switch (code) {
+               case ICMP_SR_FAILED:
+                       /* Impossible event. */
+                       goto out;
+               default:
+                       /* All others are translated to HOST_UNREACH.
+                        * rfc2003 contains "deep thoughts" about NET_UNREACH,
+                        * I believe they are just ether pollution. --ANK
+                        */
+                       break;
+               }
+               break;
+
+       case ICMP_TIME_EXCEEDED:
+               if (code != ICMP_EXC_TTL)
+                       goto out;
+               break;
+
+       case ICMP_REDIRECT:
+               break;
+
+       default:
+               goto out;
+       }
 
-       err = -ENOENT;
        t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
                             iph->daddr, iph->saddr, 0);
-       if (!t)
+       if (!t) {
+               err = -ENOENT;
                goto out;
+       }
 
        if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
-               ipv4_update_pmtu(skb, dev_net(skb->dev), info,
-                                t->parms.link, 0, iph->protocol, 0);
-               err = 0;
+               ipv4_update_pmtu(skb, net, info, t->parms.link, 0,
+                                iph->protocol, 0);
                goto out;
        }
 
        if (type == ICMP_REDIRECT) {
-               ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
-                             iph->protocol, 0);
-               err = 0;
+               ipv4_redirect(skb, net, t->parms.link, 0, iph->protocol, 0);
                goto out;
        }
 
-       if (t->parms.iph.daddr == 0)
+       if (t->parms.iph.daddr == 0) {
+               err = -ENOENT;
                goto out;
+       }
 
-       err = 0;
        if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
                goto out;