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authorAnsis Atteka <aatteka@nicira.com>2013-09-18 15:29:53 -0700
committerDavid S. Miller <davem@davemloft.net>2013-09-19 14:11:15 -0400
commit703133de331a7a7df47f31fb9de51dc6f68a9de8 (patch)
tree0c6c49e15c9461cd3a563d17062a866d2fafd6fa /include
parent749154aa56b57652a282cbde57a57abc278d1205 (diff)
ip: generate unique IP identificator if local fragmentation is allowed
If local fragmentation is allowed, then ip_select_ident() and ip_select_ident_more() need to generate unique IDs to ensure correct defragmentation on the peer. For example, if IPsec (tunnel mode) has to encrypt large skbs that have local_df bit set, then all IP fragments that belonged to different ESP datagrams would have used the same identificator. If one of these IP fragments would get lost or reordered, then peer could possibly stitch together wrong IP fragments that did not belong to the same datagram. This would lead to a packet loss or data corruption. Signed-off-by: Ansis Atteka <aatteka@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/ip.h12
1 files changed, 8 insertions, 4 deletions
diff --git a/include/net/ip.h b/include/net/ip.h
index 48f55979d842..5e5268807a1c 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -264,9 +264,11 @@ int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
-static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
+static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
{
- if (iph->frag_off & htons(IP_DF)) {
+ struct iphdr *iph = ip_hdr(skb);
+
+ if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
/* This is only to work around buggy Windows95/2000
* VJ compression implementations. If the ID field
* does not change, they drop every other packet in
@@ -278,9 +280,11 @@ static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, str
__ip_select_ident(iph, dst, 0);
}
-static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
+static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
{
- if (iph->frag_off & htons(IP_DF)) {
+ struct iphdr *iph = ip_hdr(skb);
+
+ if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
if (sk && inet_sk(sk)->inet_daddr) {
iph->id = htons(inet_sk(sk)->inet_id);
inet_sk(sk)->inet_id += 1 + more;

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