netfilter: nf_nat: support mangling a single TCP packet multiple times

nf_nat_mangle_tcp_packet() can currently only handle a single mangling
per window because it only maintains two sequence adjustment positions:
the one before the last adjustment and the one after.

This patch makes sequence number adjustment tracking in
nf_nat_mangle_tcp_packet() optional and allows a helper to manually
update the offsets after the packet has been fully handled.

Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Patrick McHardy
2010-02-11 12:27:09 +01:00
parent f5b321bd37
commit 010c0b9f34
2 changed files with 48 additions and 23 deletions

View File

@@ -7,13 +7,27 @@
struct sk_buff;
/* These return true or false. */
extern int nf_nat_mangle_tcp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len);
extern int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len, bool adjust);
static inline int nf_nat_mangle_tcp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len)
{
return __nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
match_offset, match_len,
rep_buffer, rep_len, true);
}
extern int nf_nat_mangle_udp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
@@ -21,6 +35,10 @@ extern int nf_nat_mangle_udp_packet(struct sk_buff *skb,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len);
extern void nf_nat_set_seq_adjust(struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
__be32 seq, s16 off);
extern int nf_nat_seq_adjust(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo);