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gre: fix error handler

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1) gre_parse_header() can be called from gre_err()

   At this point transport header points to ICMP header, not the inner
header.

2) We can not really change transport header as ipgre_err() will later
assume transport header still points to ICMP header (using icmp_hdr())

3) pskb_may_pull() logic in gre_parse_header() really works
  if we are interested at zone pointed by skb->data

4) As Jiri explained in commit b7f8fe251e ("gre: do not pull header in
ICMP error processing") we should not pull headers in error handler.

So this fix :

A) changes gre_parse_header() to use skb->data instead of
skb_transport_header()

B) Adds a nhs parameter to gre_parse_header() so that we can skip the
not pulled IP header from error path.
  This offset is 0 for normal receive path.

C) remove obsolete IPV6 includes

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2016-06-15 06:24:00 -07:00
committed by David S. Miller
parent daddef76c3
commit e582615ad3
4 changed files with 11 additions and 15 deletions
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12
net/ipv4/ip_gre.c
View File

@@ -49,12 +49,6 @@
#include <net/gre.h>
#include <net/dst_metadata.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#endif
/*
Problems & solutions
--------------------
@@ -217,12 +211,14 @@ static void gre_err(struct sk_buff *skb, u32 info)
* by themselves???
*/
const struct iphdr *iph = (struct iphdr *)skb->data;
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
struct tnl_ptk_info tpi;
bool csum_err = false;
if (gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP)) < 0) {
if (gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP),
iph->ihl * 4) < 0) {
if (!csum_err) /* ignore csum errors. */
return;
}
@@ -338,7 +334,7 @@ static int gre_rcv(struct sk_buff *skb)
}
#endif
hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP));
hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP), 0);
if (hdr_len < 0)
goto drop;