ip_tunnel: Do not use inner ip-header-id for tunnel ip-header-id.

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.)

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

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 781b3cf86a2f534ff71e03037b7984a0e84a8c8e..a354db5b7662f1bce43af7edc97471cdef3421bb 100644 (file)
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -145,20 +145,6 @@ 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);
-}
-
 int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto);
 int iptunnel_xmit(struct net *net, struct rtable *rt,
                  struct sk_buff *skb,

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 7167b08977df582bd38565cf960568a8553f29d4..850525b34899f3a50d0e19f6bd326821b0c2423a 100644 (file)
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -76,9 +76,7 @@ int iptunnel_xmit(struct net *net, struct rtable *rt,
        iph->daddr      =       dst;
        iph->saddr      =       src;
        iph->ttl        =       ttl;
-       tunnel_ip_select_ident(skb,
-                              (const struct iphdr *)skb_inner_network_header(skb),
-                              &rt->dst);
+       __ip_select_ident(iph, &rt->dst, (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 
        err = ip_local_out(skb);
        if (unlikely(net_xmit_eval(err)))