[NETFILTER]: nf_conntrack_sip: introduce SIP-URI parsing helper
Introduce a helper function to parse a SIP-URI in a header value, optionally
iterating through all headers of this kind.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index cbc9159..a74d76a 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -190,6 +190,9 @@
* whitespace and the values. Whitespace in this context means any amount of
* tabs, spaces and continuation lines, which are treated as a single whitespace
* character.
+ *
+ * Some headers may appear multiple times. A comma seperated list of values is
+ * equivalent to multiple headers.
*/
static const struct sip_header ct_sip_hdrs[] = {
[SIP_HDR_FROM] = SIP_HDR("From", "f", "sip:", skp_epaddr_len),
@@ -322,6 +325,110 @@
}
EXPORT_SYMBOL_GPL(ct_sip_get_header);
+/* Get next header field in a list of comma seperated values */
+static int ct_sip_next_header(const struct nf_conn *ct, const char *dptr,
+ unsigned int dataoff, unsigned int datalen,
+ enum sip_header_types type,
+ unsigned int *matchoff, unsigned int *matchlen)
+{
+ const struct sip_header *hdr = &ct_sip_hdrs[type];
+ const char *start = dptr, *limit = dptr + datalen;
+ int shift = 0;
+
+ dptr += dataoff;
+
+ dptr = ct_sip_header_search(dptr, limit, ",", strlen(","));
+ if (!dptr)
+ return 0;
+
+ dptr = ct_sip_header_search(dptr, limit, hdr->search, hdr->slen);
+ if (!dptr)
+ return 0;
+ dptr += hdr->slen;
+
+ *matchoff = dptr - start;
+ *matchlen = hdr->match_len(ct, dptr, limit, &shift);
+ if (!*matchlen)
+ return -1;
+ *matchoff += shift;
+ return 1;
+}
+
+/* Walk through headers until a parsable one is found or no header of the
+ * given type is left. */
+static int ct_sip_walk_headers(const struct nf_conn *ct, const char *dptr,
+ unsigned int dataoff, unsigned int datalen,
+ enum sip_header_types type, int *in_header,
+ unsigned int *matchoff, unsigned int *matchlen)
+{
+ int ret;
+
+ if (in_header && *in_header) {
+ while (1) {
+ ret = ct_sip_next_header(ct, dptr, dataoff, datalen,
+ type, matchoff, matchlen);
+ if (ret > 0)
+ return ret;
+ if (ret == 0)
+ break;
+ dataoff += *matchoff;
+ }
+ *in_header = 0;
+ }
+
+ while (1) {
+ ret = ct_sip_get_header(ct, dptr, dataoff, datalen,
+ type, matchoff, matchlen);
+ if (ret > 0)
+ break;
+ if (ret == 0)
+ return ret;
+ dataoff += *matchoff;
+ }
+
+ if (in_header)
+ *in_header = 1;
+ return 1;
+}
+
+/* Locate a SIP header, parse the URI and return the offset and length of
+ * the address as well as the address and port themselves. A stream of
+ * headers can be parsed by handing in a non-NULL datalen and in_header
+ * pointer.
+ */
+int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr,
+ unsigned int *dataoff, unsigned int datalen,
+ enum sip_header_types type, int *in_header,
+ unsigned int *matchoff, unsigned int *matchlen,
+ union nf_inet_addr *addr, __be16 *port)
+{
+ const char *c, *limit = dptr + datalen;
+ unsigned int p;
+ int ret;
+
+ ret = ct_sip_walk_headers(ct, dptr, dataoff ? *dataoff : 0, datalen,
+ type, in_header, matchoff, matchlen);
+ WARN_ON(ret < 0);
+ if (ret == 0)
+ return ret;
+
+ if (!parse_addr(ct, dptr + *matchoff, &c, addr, limit))
+ return -1;
+ if (*c == ':') {
+ c++;
+ p = simple_strtoul(c, (char **)&c, 10);
+ if (p < 1024 || p > 65535)
+ return -1;
+ *port = htons(p);
+ } else
+ *port = htons(SIP_PORT);
+
+ if (dataoff)
+ *dataoff = c - dptr;
+ return 1;
+}
+EXPORT_SYMBOL_GPL(ct_sip_parse_header_uri);
+
/* 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.