[PATCH][next] gre: fix TUNNEL_SEQ bit check on sequence numbering

[Colin King]

From: Colin Ian King <colin.k...@canonical.com>

The current logic of flags | TUNNEL_SEQ is always non-zero and hence
sequence numbers are always incremented no matter the setting of the
TUNNEL_SEQ bit.  Fix this by using & instead of |.

Detected by CoverityScan, CID#1466039 ("Operands don't affect result")

Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.")
Signed-off-by: Colin Ian King <colin.k...@canonical.com>
---
 net/ipv4/ip_gre.c  | 2 +-
 net/ipv6/ip6_gre.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 2fa2ef2e2af9..9ab1aa2f7660 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -550,7 +550,7 @@ static void gre_fb_xmit(struct sk_buff *skb, struct 
net_device *dev,
                (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
        gre_build_header(skb, tunnel_hlen, flags, proto,
                         tunnel_id_to_key32(tun_info->key.tun_id),
-                        (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
+                        (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
 
        df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;
 
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0bcefc480aeb..3a98c694da5f 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -725,7 +725,7 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
                gre_build_header(skb, tunnel->tun_hlen,
                                 flags, protocol,
                                 tunnel_id_to_key32(tun_info->key.tun_id),
-                                (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
+                                (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
                                                      : 0);
 
        } else {
-- 
2.15.1