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authorStephen Suryaputra <ssuryaextr@gmail.com>2019-06-26 02:21:16 -0400
committerDavid S. Miller <davem@davemloft.net>2019-06-26 12:40:10 -0700
commit5b18f1289808fee5d04a7e6ecf200189f41a4db6 (patch)
treec4f8ffda52e1fa30489d1eae8c7f4066c0fc2df6 /net/ipv4/ip_output.c
parentee4297420d56a0033a8593e80b33fcc93fda8509 (diff)
ipv4: reset rt_iif for recirculated mcast/bcast out pkts
Multicast or broadcast egress packets have rt_iif set to the oif. These packets might be recirculated back as input and lookup to the raw sockets may fail because they are bound to the incoming interface (skb_iif). If rt_iif is not zero, during the lookup, inet_iif() function returns rt_iif instead of skb_iif. Hence, the lookup fails. v2: Make it non vrf specific (David Ahern). Reword the changelog to reflect it. Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_output.c')
-rw-r--r--net/ipv4/ip_output.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 16f9159234a2..8c2ec35b6512 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -318,6 +318,7 @@ static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *sk
static int ip_mc_finish_output(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
+ struct rtable *new_rt;
int ret;
ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
@@ -326,6 +327,17 @@ static int ip_mc_finish_output(struct net *net, struct sock *sk,
return ret;
}
+ /* Reset rt_iif so that inet_iif() will return skb->skb_iif. Setting
+ * this to non-zero causes ipi_ifindex in in_pktinfo to be overwritten,
+ * see ipv4_pktinfo_prepare().
+ */
+ new_rt = rt_dst_clone(net->loopback_dev, skb_rtable(skb));
+ if (new_rt) {
+ new_rt->rt_iif = 0;
+ skb_dst_drop(skb);
+ skb_dst_set(skb, &new_rt->dst);
+ }
+
return dev_loopback_xmit(net, sk, skb);
}