Commit d8c6f4b9 authored Mar 01, 2013 by Neil Horman Committed by David S. Miller Mar 01, 2013

ipv[4|6]: correct dropwatch false positive in local_deliver_finish



I had a report recently of a user trying to use dropwatch to localise some frame
loss, and they were getting false positives.  Turned out they were using a user
space SCTP stack that used raw sockets to grab frames.  When we don't have a
registered protocol for a given packet, we record it as a drop, even if a raw
socket receieves the frame.  We should only record the drop in the event a raw
socket doesnt exist to receive the frames

Tested by the reported successfully

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: William Reich <reich@ulticom.com>
Tested-by: William Reich <reich@ulticom.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: William Reich <reich@ulticom.com>
CC: eric.dumazet@gmail.com
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 9e0aab86

net/ipv4/ip_input.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -228,9 +228,11 @@ static int ip_local_deliver_finish(struct sk_buff *skb)
	icmp_send(skb, ICMP_DEST_UNREACH,		icmp_send(skb, ICMP_DEST_UNREACH,
	ICMP_PROT_UNREACH, 0);		ICMP_PROT_UNREACH, 0);
	}		}
	} else
	IP_INC_STATS_BH(net, IPSTATS_MIB_INDELIVERS);
	kfree_skb(skb);		kfree_skb(skb);
			} else {
			IP_INC_STATS_BH(net, IPSTATS_MIB_INDELIVERS);
			consume_skb(skb);
			}
	}		}
	}		}
	out:		out:

net/ipv6/ip6_input.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -241,9 +241,11 @@ static int ip6_input_finish(struct sk_buff *skb)
	icmpv6_send(skb, ICMPV6_PARAMPROB,		icmpv6_send(skb, ICMPV6_PARAMPROB,
	ICMPV6_UNK_NEXTHDR, nhoff);		ICMPV6_UNK_NEXTHDR, nhoff);
	}		}
	} else
	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
	kfree_skb(skb);		kfree_skb(skb);
			} else {
			IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
			consume_skb(skb);
			}
	}		}
	rcu_read_unlock();		rcu_read_unlock();
	return 0;		return 0;