From 935a9749a36828af0e8be224a5cd4bc758112c34 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sun, 1 Oct 2017 22:00:53 +0800 Subject: [PATCH] ip_gre: get key from session_id correctly in erspan_rcv erspan only uses the first 10 bits of session_id as the key to look up the tunnel. But in erspan_rcv, it missed 'session_id & ID_MASK' when getting the key from session_id. If any other flag is also set in session_id in a packet, it would fail to find the tunnel due to incorrect key in erspan_rcv. This patch is to add 'session_id & ID_MASK' there and also remove the unnecessary variable session_id. Fixes: 84e54fe0a5ea ("gre: introduce native tunnel support for ERSPAN") Signed-off-by: Xin Long Signed-off-by: David S. Miller --- net/ipv4/ip_gre.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 8b837f6f5532..b25b1e5112d0 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -259,7 +259,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, struct ip_tunnel *tunnel; struct erspanhdr *ershdr; const struct iphdr *iph; - __be32 session_id; __be32 index; int len; @@ -275,8 +274,7 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, /* The original GRE header does not have key field, * Use ERSPAN 10-bit session ID as key. */ - session_id = cpu_to_be32(ntohs(ershdr->session_id)); - tpi->key = session_id; + tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK); index = ershdr->md.index; tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags | TUNNEL_KEY, -- 2.11.0