[NETFILTER]: Add SIP connection tracking helper

Add SIP connection tracking helper. Originally written by
Christian Hentschel <chentschel@arnet.com.ar>, some cleanup, minor
fixes and bidirectional SIP support added by myself.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 44 insertions, 0 deletions

diff --git a/include/linux/netfilter_ipv4/ip_conntrack_sip.h b/include/linux/netfilter_ipv4/ip_conntrack_sip.h
new file mode 100644
index 000000000000..913dad66c0fb
--- /dev/null
+++ b/include/linux/netfilter_ipv4/ip_conntrack_sip.h
@@ -0,0 +1,44 @@
+#ifndef __IP_CONNTRACK_SIP_H__
+#define __IP_CONNTRACK_SIP_H__
+#ifdef __KERNEL__
+
+#define SIP_PORT        5060
+#define SIP_TIMEOUT     3600
+
+#define POS_VIA         0
+#define POS_CONTACT     1
+#define POS_CONTENT     2
+#define POS_MEDIA       3
+#define POS_OWNER       4
+#define POS_CONNECTION  5
+#define POS_REQ_HEADER  6
+#define POS_SDP_HEADER  7
+
+struct sip_header_nfo {
+        const char      *lname;
+        const char      *sname;
+        const char      *ln_str;
+        size_t          lnlen;
+        size_t          snlen;
+        size_t          ln_strlen;
+        int             (*match_len)(const char *, const char *, int *);
+};
+
+extern unsigned int (*ip_nat_sip_hook)(struct sk_buff **pskb,
+                                       enum ip_conntrack_info ctinfo,
+                                       struct ip_conntrack *ct,
+                                       const char **dptr);
+extern unsigned int (*ip_nat_sdp_hook)(struct sk_buff **pskb,
+                                       enum ip_conntrack_info ctinfo,
+                                       struct ip_conntrack_expect *exp,
+                                       const char *dptr);
+
+extern int ct_sip_get_info(const char *dptr, size_t dlen,
+                           unsigned int *matchoff,
+                           unsigned int *matchlen,
+                           struct sip_header_nfo *hnfo);
+extern int ct_sip_lnlen(const char *line, const char *limit);
+extern const char *ct_sip_search(const char *needle, const char *haystack,
+                                 size_t needle_len, size_t haystack_len);
+#endif /* __KERNEL__ */
+#endif /* __IP_CONNTRACK_SIP_H__ */