ip_tunnel: Do not use inner ip-header-id for tunnel ip-header-id.
Pravin B Shelar [Tue, 13 Aug 2013 08:41:06 +0000 (01:41 -0700)]
[ Upstream commit 4221f40513233fa8edeef7fc82e44163fde03b9b ]

Using inner-id for tunnel id is not safe in some rare cases.
E.g. packets coming from multiple sources entering same tunnel
can have same id. Therefore on tunnel packet receive we
could have packets from two different stream but with same
source and dst IP with same ip-id which could confuse ip packet
reassembly.

Following patch reverts optimization from commit
490ab08127 (IP_GRE: Fix IP-Identification.)

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
CC: Jarno Rajahalme <jrajahalme@nicira.com>
CC: Ansis Atteka <aatteka@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/vxlan.c
include/net/ip_tunnels.h
net/ipv4/ip_tunnel.c

index 57325f3..054489f 100644 (file)
@@ -1090,7 +1090,7 @@ static netdev_tx_t vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
        iph->daddr      = dst;
        iph->saddr      = fl4.saddr;
        iph->ttl        = ttl ? : ip4_dst_hoplimit(&rt->dst);
-       tunnel_ip_select_ident(skb, old_iph, &rt->dst);
+       __ip_select_ident(iph, &rt->dst, (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 
        nf_reset(skb);
 
index 09b1360..a9942e1 100644 (file)
@@ -141,20 +141,6 @@ static inline u8 ip_tunnel_ecn_encap(u8 tos, const struct iphdr *iph,
        return INET_ECN_encapsulate(tos, inner);
 }
 
-static inline void tunnel_ip_select_ident(struct sk_buff *skb,
-                                         const struct iphdr  *old_iph,
-                                         struct dst_entry *dst)
-{
-       struct iphdr *iph = ip_hdr(skb);
-
-       /* Use inner packet iph-id if possible. */
-       if (skb->protocol == htons(ETH_P_IP) && old_iph->id)
-               iph->id = old_iph->id;
-       else
-               __ip_select_ident(iph, dst,
-                                 (skb_shinfo(skb)->gso_segs ?: 1) - 1);
-}
-
 static inline void iptunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        int err;
index cbfc37f..b7a4c21 100644 (file)
@@ -686,7 +686,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
        iph->daddr      =       fl4.daddr;
        iph->saddr      =       fl4.saddr;
        iph->ttl        =       ttl;
-       tunnel_ip_select_ident(skb, inner_iph, &rt->dst);
+       __ip_select_ident(iph, &rt->dst, (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 
        iptunnel_xmit(skb, dev);
        return;