linux/include/net/gre.h
Eric Dumazet e582615ad3 gre: fix error handler
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>
2016-06-15 22:15:21 -07:00

133 lines
2.8 KiB
C

#ifndef __LINUX_GRE_H
#define __LINUX_GRE_H
#include <linux/skbuff.h>
#include <net/ip_tunnels.h>
struct gre_base_hdr {
__be16 flags;
__be16 protocol;
};
#define GRE_HEADER_SECTION 4
#define GREPROTO_CISCO 0
#define GREPROTO_PPTP 1
#define GREPROTO_MAX 2
#define GRE_IP_PROTO_MAX 2
struct gre_protocol {
int (*handler)(struct sk_buff *skb);
void (*err_handler)(struct sk_buff *skb, u32 info);
};
int gre_add_protocol(const struct gre_protocol *proto, u8 version);
int gre_del_protocol(const struct gre_protocol *proto, u8 version);
struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
u8 name_assign_type);
int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
bool *csum_err, __be16 proto, int nhs);
static inline int gre_calc_hlen(__be16 o_flags)
{
int addend = 4;
if (o_flags & TUNNEL_CSUM)
addend += 4;
if (o_flags & TUNNEL_KEY)
addend += 4;
if (o_flags & TUNNEL_SEQ)
addend += 4;
return addend;
}
static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
{
__be16 tflags = 0;
if (flags & GRE_CSUM)
tflags |= TUNNEL_CSUM;
if (flags & GRE_ROUTING)
tflags |= TUNNEL_ROUTING;
if (flags & GRE_KEY)
tflags |= TUNNEL_KEY;
if (flags & GRE_SEQ)
tflags |= TUNNEL_SEQ;
if (flags & GRE_STRICT)
tflags |= TUNNEL_STRICT;
if (flags & GRE_REC)
tflags |= TUNNEL_REC;
if (flags & GRE_VERSION)
tflags |= TUNNEL_VERSION;
return tflags;
}
static inline __be16 gre_tnl_flags_to_gre_flags(__be16 tflags)
{
__be16 flags = 0;
if (tflags & TUNNEL_CSUM)
flags |= GRE_CSUM;
if (tflags & TUNNEL_ROUTING)
flags |= GRE_ROUTING;
if (tflags & TUNNEL_KEY)
flags |= GRE_KEY;
if (tflags & TUNNEL_SEQ)
flags |= GRE_SEQ;
if (tflags & TUNNEL_STRICT)
flags |= GRE_STRICT;
if (tflags & TUNNEL_REC)
flags |= GRE_REC;
if (tflags & TUNNEL_VERSION)
flags |= GRE_VERSION;
return flags;
}
static inline __sum16 gre_checksum(struct sk_buff *skb)
{
__wsum csum;
if (skb->ip_summed == CHECKSUM_PARTIAL)
csum = lco_csum(skb);
else
csum = skb_checksum(skb, 0, skb->len, 0);
return csum_fold(csum);
}
static inline void gre_build_header(struct sk_buff *skb, int hdr_len,
__be16 flags, __be16 proto,
__be32 key, __be32 seq)
{
struct gre_base_hdr *greh;
skb_push(skb, hdr_len);
skb_reset_transport_header(skb);
greh = (struct gre_base_hdr *)skb->data;
greh->flags = gre_tnl_flags_to_gre_flags(flags);
greh->protocol = proto;
if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
if (flags & TUNNEL_SEQ) {
*ptr = seq;
ptr--;
}
if (flags & TUNNEL_KEY) {
*ptr = key;
ptr--;
}
if (flags & TUNNEL_CSUM &&
!(skb_shinfo(skb)->gso_type &
(SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
*ptr = 0;
*(__sum16 *)ptr = gre_checksum(skb);
}
}
}
#endif