[NETFILTER]: nf_conntrack_sip: introduce URI and header parameter parsing helpers

Introduce URI and header parameter parsing helpers. These are needed
by the conntrack helper to parse expiration values in Contact: header
parameters and by the NAT helper to properly update the Via-header
rport=, received= and maddr= parameters.

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

2 files changed, 68 insertions, 0 deletions

diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h
index da93e80804c2..87e402825dba 100644
--- a/include/linux/netfilter/nf_conntrack_sip.h
+++ b/include/linux/netfilter/nf_conntrack_sip.h
@@ -93,6 +93,16 @@ extern int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr,
                                    enum sip_header_types type, int *in_header,
                                    unsigned int *matchoff, unsigned int *matchlen,
                                    union nf_inet_addr *addr, __be16 *port);
+extern int ct_sip_parse_address_param(const struct nf_conn *ct, const char *dptr,
+                                      unsigned int dataoff, unsigned int datalen,
+                                      const char *name,
+                                      unsigned int *matchoff, unsigned int *matchlen,
+                                      union nf_inet_addr *addr);
+extern int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr,
+                                        unsigned int off, unsigned int datalen,
+                                        const char *name,
+                                        unsigned int *matchoff, unsigned int *matchen,
+                                        unsigned int *val);
 
 extern int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr,
                                  unsigned int dataoff, unsigned int datalen,
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 8e7e5b465ffb..126f30842d60 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -448,6 +448,64 @@ int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr,
 }
 EXPORT_SYMBOL_GPL(ct_sip_parse_header_uri);
 
+/* Parse address from header parameter and return address, offset and length */
+int ct_sip_parse_address_param(const struct nf_conn *ct, const char *dptr,
+                               unsigned int dataoff, unsigned int datalen,
+                               const char *name,
+                               unsigned int *matchoff, unsigned int *matchlen,
+                               union nf_inet_addr *addr)
+{
+        const char *limit = dptr + datalen;
+        const char *start, *end;
+
+        limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(","));
+        if (!limit)
+                limit = dptr + datalen;
+
+        start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name));
+        if (!start)
+                return 0;
+
+        start += strlen(name);
+        if (!parse_addr(ct, start, &end, addr, limit))
+                return 0;
+        *matchoff = start - dptr;
+        *matchlen = end - start;
+        return 1;
+}
+EXPORT_SYMBOL_GPL(ct_sip_parse_address_param);
+
+/* Parse numerical header parameter and return value, offset and length */
+int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr,
+                                 unsigned int dataoff, unsigned int datalen,
+                                 const char *name,
+                                 unsigned int *matchoff, unsigned int *matchlen,
+                                 unsigned int *val)
+{
+        const char *limit = dptr + datalen;
+        const char *start;
+        char *end;
+
+        limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(","));
+        if (!limit)
+                limit = dptr + datalen;
+
+        start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name));
+        if (!start)
+                return 0;
+
+        start += strlen(name);
+        *val = simple_strtoul(start, &end, 0);
+        if (start == end)
+                return 0;
+        if (matchoff && matchlen) {
+                *matchoff = start - dptr;
+                *matchlen = end - start;
+        }
+        return 1;
+}
+EXPORT_SYMBOL_GPL(ct_sip_parse_numerical_param);
+
 /* SDP header parsing: a SDP session description contains an ordered set of
  * headers, starting with a section containing general session parameters,
  * optionally followed by multiple media descriptions.