*
* (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar>
* based on RR's ip_conntrack_ftp.c and other modules.
+ * (C) 2007 United Security Providers
+ * (C) 2007, 2008 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
#include <linux/inet.h>
#include <linux/in.h>
#include <linux/udp.h>
+#include <linux/tcp.h>
#include <linux/netfilter.h>
#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_zones.h>
#include <linux/netfilter/nf_conntrack_sip.h>
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(format, args...)
-#endif
-
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>");
MODULE_DESCRIPTION("SIP connection tracking helper");
MODULE_ALIAS("ip_conntrack_sip");
+MODULE_ALIAS_NFCT_HELPER("sip");
#define MAX_PORTS 8
static unsigned short ports[MAX_PORTS];
-static int ports_c;
+static unsigned int ports_c;
module_param_array(ports, ushort, &ports_c, 0400);
MODULE_PARM_DESC(ports, "port numbers of SIP servers");
module_param(sip_timeout, uint, 0600);
MODULE_PARM_DESC(sip_timeout, "timeout for the master SIP session");
-unsigned int (*nf_nat_sip_hook)(struct sk_buff **pskb,
- enum ip_conntrack_info ctinfo,
- struct nf_conn *ct,
- const char **dptr) __read_mostly;
+static int sip_direct_signalling __read_mostly = 1;
+module_param(sip_direct_signalling, int, 0600);
+MODULE_PARM_DESC(sip_direct_signalling, "expect incoming calls from registrar "
+ "only (default 1)");
+
+static int sip_direct_media __read_mostly = 1;
+module_param(sip_direct_media, int, 0600);
+MODULE_PARM_DESC(sip_direct_media, "Expect Media streams between signalling "
+ "endpoints only (default 1)");
+
+unsigned int (*nf_nat_sip_hook)(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr,
+ unsigned int *datalen) __read_mostly;
EXPORT_SYMBOL_GPL(nf_nat_sip_hook);
-unsigned int (*nf_nat_sdp_hook)(struct sk_buff **pskb,
- enum ip_conntrack_info ctinfo,
- struct nf_conntrack_expect *exp,
- const char *dptr) __read_mostly;
-EXPORT_SYMBOL_GPL(nf_nat_sdp_hook);
-
-static int digits_len(struct nf_conn *, const char *, const char *, int *);
-static int epaddr_len(struct nf_conn *, const char *, const char *, int *);
-static int skp_digits_len(struct nf_conn *, const char *, const char *, int *);
-static int skp_epaddr_len(struct nf_conn *, const char *, const char *, int *);
-
-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 case_sensitive;
- int (*match_len)(struct nf_conn *, const char *,
- const char *, int *);
-};
+void (*nf_nat_sip_seq_adjust_hook)(struct sk_buff *skb, s16 off) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sip_seq_adjust_hook);
-static const struct sip_header_nfo ct_sip_hdrs[] = {
- [POS_REG_REQ_URI] = { /* SIP REGISTER request URI */
- .lname = "sip:",
- .lnlen = sizeof("sip:") - 1,
- .ln_str = ":",
- .ln_strlen = sizeof(":") - 1,
- .match_len = epaddr_len,
- },
- [POS_REQ_URI] = { /* SIP request URI */
- .lname = "sip:",
- .lnlen = sizeof("sip:") - 1,
- .ln_str = "@",
- .ln_strlen = sizeof("@") - 1,
- .match_len = epaddr_len,
- },
- [POS_FROM] = { /* SIP From header */
- .lname = "From:",
- .lnlen = sizeof("From:") - 1,
- .sname = "\r\nf:",
- .snlen = sizeof("\r\nf:") - 1,
- .ln_str = "sip:",
- .ln_strlen = sizeof("sip:") - 1,
- .match_len = skp_epaddr_len,
- },
- [POS_TO] = { /* SIP To header */
- .lname = "To:",
- .lnlen = sizeof("To:") - 1,
- .sname = "\r\nt:",
- .snlen = sizeof("\r\nt:") - 1,
- .ln_str = "sip:",
- .ln_strlen = sizeof("sip:") - 1,
- .match_len = skp_epaddr_len
- },
- [POS_VIA] = { /* SIP Via header */
- .lname = "Via:",
- .lnlen = sizeof("Via:") - 1,
- .sname = "\r\nv:",
- .snlen = sizeof("\r\nv:") - 1, /* rfc3261 "\r\n" */
- .ln_str = "UDP ",
- .ln_strlen = sizeof("UDP ") - 1,
- .match_len = epaddr_len,
- },
- [POS_CONTACT] = { /* SIP Contact header */
- .lname = "Contact:",
- .lnlen = sizeof("Contact:") - 1,
- .sname = "\r\nm:",
- .snlen = sizeof("\r\nm:") - 1,
- .ln_str = "sip:",
- .ln_strlen = sizeof("sip:") - 1,
- .match_len = skp_epaddr_len
- },
- [POS_CONTENT] = { /* SIP Content length header */
- .lname = "Content-Length:",
- .lnlen = sizeof("Content-Length:") - 1,
- .sname = "\r\nl:",
- .snlen = sizeof("\r\nl:") - 1,
- .ln_str = ":",
- .ln_strlen = sizeof(":") - 1,
- .match_len = skp_digits_len
- },
- [POS_MEDIA] = { /* SDP media info */
- .case_sensitive = 1,
- .lname = "\nm=",
- .lnlen = sizeof("\nm=") - 1,
- .sname = "\rm=",
- .snlen = sizeof("\rm=") - 1,
- .ln_str = "audio ",
- .ln_strlen = sizeof("audio ") - 1,
- .match_len = digits_len
- },
- [POS_OWNER_IP4] = { /* SDP owner address*/
- .case_sensitive = 1,
- .lname = "\no=",
- .lnlen = sizeof("\no=") - 1,
- .sname = "\ro=",
- .snlen = sizeof("\ro=") - 1,
- .ln_str = "IN IP4 ",
- .ln_strlen = sizeof("IN IP4 ") - 1,
- .match_len = epaddr_len
- },
- [POS_CONNECTION_IP4] = {/* SDP connection info */
- .case_sensitive = 1,
- .lname = "\nc=",
- .lnlen = sizeof("\nc=") - 1,
- .sname = "\rc=",
- .snlen = sizeof("\rc=") - 1,
- .ln_str = "IN IP4 ",
- .ln_strlen = sizeof("IN IP4 ") - 1,
- .match_len = epaddr_len
- },
- [POS_OWNER_IP6] = { /* SDP owner address*/
- .case_sensitive = 1,
- .lname = "\no=",
- .lnlen = sizeof("\no=") - 1,
- .sname = "\ro=",
- .snlen = sizeof("\ro=") - 1,
- .ln_str = "IN IP6 ",
- .ln_strlen = sizeof("IN IP6 ") - 1,
- .match_len = epaddr_len
- },
- [POS_CONNECTION_IP6] = {/* SDP connection info */
- .case_sensitive = 1,
- .lname = "\nc=",
- .lnlen = sizeof("\nc=") - 1,
- .sname = "\rc=",
- .snlen = sizeof("\rc=") - 1,
- .ln_str = "IN IP6 ",
- .ln_strlen = sizeof("IN IP6 ") - 1,
- .match_len = epaddr_len
- },
- [POS_SDP_HEADER] = { /* SDP version header */
- .case_sensitive = 1,
- .lname = "\nv=",
- .lnlen = sizeof("\nv=") - 1,
- .sname = "\rv=",
- .snlen = sizeof("\rv=") - 1,
- .ln_str = "=",
- .ln_strlen = sizeof("=") - 1,
- .match_len = digits_len
- }
-};
+unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb,
+ unsigned int dataoff,
+ const char **dptr,
+ unsigned int *datalen,
+ struct nf_conntrack_expect *exp,
+ unsigned int matchoff,
+ unsigned int matchlen) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sip_expect_hook);
-/* get line lenght until first CR or LF seen. */
-int ct_sip_lnlen(const char *line, const char *limit)
-{
- const char *k = line;
+unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr,
+ unsigned int *datalen,
+ unsigned int sdpoff,
+ enum sdp_header_types type,
+ enum sdp_header_types term,
+ const union nf_inet_addr *addr)
+ __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_addr_hook);
- while ((line <= limit) && (*line == '\r' || *line == '\n'))
- line++;
+unsigned int (*nf_nat_sdp_port_hook)(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr,
+ unsigned int *datalen,
+ unsigned int matchoff,
+ unsigned int matchlen,
+ u_int16_t port) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_port_hook);
- while (line <= limit) {
- if (*line == '\r' || *line == '\n')
- break;
- line++;
- }
- return line - k;
-}
-EXPORT_SYMBOL_GPL(ct_sip_lnlen);
+unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb,
+ unsigned int dataoff,
+ const char **dptr,
+ unsigned int *datalen,
+ unsigned int sdpoff,
+ const union nf_inet_addr *addr)
+ __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_session_hook);
+
+unsigned int (*nf_nat_sdp_media_hook)(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr,
+ unsigned int *datalen,
+ struct nf_conntrack_expect *rtp_exp,
+ struct nf_conntrack_expect *rtcp_exp,
+ unsigned int mediaoff,
+ unsigned int medialen,
+ union nf_inet_addr *rtp_addr)
+ __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_media_hook);
-/* Linear string search, case sensitive. */
-const char *ct_sip_search(const char *needle, const char *haystack,
- size_t needle_len, size_t haystack_len,
- int case_sensitive)
+static int string_len(const struct nf_conn *ct, const char *dptr,
+ const char *limit, int *shift)
{
- const char *limit = haystack + (haystack_len - needle_len);
+ int len = 0;
- while (haystack <= limit) {
- if (case_sensitive) {
- if (strncmp(haystack, needle, needle_len) == 0)
- return haystack;
- } else {
- if (strnicmp(haystack, needle, needle_len) == 0)
- return haystack;
- }
- haystack++;
+ while (dptr < limit && isalpha(*dptr)) {
+ dptr++;
+ len++;
}
- return NULL;
+ return len;
}
-EXPORT_SYMBOL_GPL(ct_sip_search);
-static int digits_len(struct nf_conn *ct, const char *dptr,
+static int digits_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
{
int len = 0;
- while (dptr <= limit && isdigit(*dptr)) {
+ while (dptr < limit && isdigit(*dptr)) {
dptr++;
len++;
}
return len;
}
-/* get digits lenght, skiping blank spaces. */
-static int skp_digits_len(struct nf_conn *ct, const char *dptr,
- const char *limit, int *shift)
+/* get media type + port length */
+static int media_len(const struct nf_conn *ct, const char *dptr,
+ const char *limit, int *shift)
{
- for (; dptr <= limit && *dptr == ' '; dptr++)
- (*shift)++;
+ int len = string_len(ct, dptr, limit, shift);
+
+ dptr += len;
+ if (dptr >= limit || *dptr != ' ')
+ return 0;
+ len++;
+ dptr++;
- return digits_len(ct, dptr, limit, shift);
+ return len + digits_len(ct, dptr, limit, shift);
}
-static int parse_addr(struct nf_conn *ct, const char *cp, const char **endp,
- union nf_conntrack_address *addr, const char *limit)
+static int parse_addr(const struct nf_conn *ct, const char *cp,
+ const char **endp, union nf_inet_addr *addr,
+ const char *limit)
{
const char *end;
- int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
int ret = 0;
- switch (family) {
+ memset(addr, 0, sizeof(*addr));
+ switch (nf_ct_l3num(ct)) {
case AF_INET:
ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end);
break;
}
/* skip ip address. returns its length. */
-static int epaddr_len(struct nf_conn *ct, const char *dptr,
+static int epaddr_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
{
- union nf_conntrack_address addr;
+ union nf_inet_addr addr;
const char *aux = dptr;
if (!parse_addr(ct, dptr, &dptr, &addr, limit)) {
- DEBUGP("ip: %s parse failed.!\n", dptr);
+ pr_debug("ip: %s parse failed.!\n", dptr);
return 0;
}
}
/* get address length, skiping user info. */
-static int skp_epaddr_len(struct nf_conn *ct, const char *dptr,
+static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
{
+ const char *start = dptr;
int s = *shift;
/* Search for @, but stop at the end of the line.
* We are inside a sip: URI, so we don't need to worry about
* continuation lines. */
- while (dptr <= limit &&
+ while (dptr < limit &&
*dptr != '@' && *dptr != '\r' && *dptr != '\n') {
(*shift)++;
dptr++;
}
- if (dptr <= limit && *dptr == '@') {
+ if (dptr < limit && *dptr == '@') {
dptr++;
(*shift)++;
- } else
+ } else {
+ dptr = start;
*shift = s;
+ }
return epaddr_len(ct, dptr, limit, shift);
}
-/* Returns 0 if not found, -1 error parsing. */
-int ct_sip_get_info(struct nf_conn *ct,
- const char *dptr, size_t dlen,
- unsigned int *matchoff,
- unsigned int *matchlen,
- enum sip_header_pos pos)
+/* Parse a SIP request line of the form:
+ *
+ * Request-Line = Method SP Request-URI SP SIP-Version CRLF
+ *
+ * and return the offset and length of the address contained in the Request-URI.
+ */
+int ct_sip_parse_request(const struct nf_conn *ct,
+ const char *dptr, unsigned int datalen,
+ unsigned int *matchoff, unsigned int *matchlen,
+ union nf_inet_addr *addr, __be16 *port)
{
- const struct sip_header_nfo *hnfo = &ct_sip_hdrs[pos];
- const char *limit, *aux, *k = dptr;
+ const char *start = dptr, *limit = dptr + datalen, *end;
+ unsigned int mlen;
+ unsigned int p;
int shift = 0;
- limit = dptr + (dlen - hnfo->lnlen);
+ /* Skip method and following whitespace */
+ mlen = string_len(ct, dptr, limit, NULL);
+ if (!mlen)
+ return 0;
+ dptr += mlen;
+ if (++dptr >= limit)
+ return 0;
- while (dptr <= limit) {
- if ((strncmp(dptr, hnfo->lname, hnfo->lnlen) != 0) &&
- (strncmp(dptr, hnfo->sname, hnfo->snlen) != 0)) {
- dptr++;
- continue;
+ /* Find SIP URI */
+ for (; dptr < limit - strlen("sip:"); dptr++) {
+ if (*dptr == '\r' || *dptr == '\n')
+ return -1;
+ if (strnicmp(dptr, "sip:", strlen("sip:")) == 0) {
+ dptr += strlen("sip:");
+ break;
}
- aux = ct_sip_search(hnfo->ln_str, dptr, hnfo->ln_strlen,
- ct_sip_lnlen(dptr, limit),
- hnfo->case_sensitive);
- if (!aux) {
- DEBUGP("'%s' not found in '%s'.\n", hnfo->ln_str,
- hnfo->lname);
+ }
+ if (!skp_epaddr_len(ct, dptr, limit, &shift))
+ return 0;
+ dptr += shift;
+
+ if (!parse_addr(ct, dptr, &end, addr, limit))
+ return -1;
+ if (end < limit && *end == ':') {
+ end++;
+ p = simple_strtoul(end, (char **)&end, 10);
+ if (p < 1024 || p > 65535)
return -1;
+ *port = htons(p);
+ } else
+ *port = htons(SIP_PORT);
+
+ if (end == dptr)
+ return 0;
+ *matchoff = dptr - start;
+ *matchlen = end - dptr;
+ return 1;
+}
+EXPORT_SYMBOL_GPL(ct_sip_parse_request);
+
+/* SIP header parsing: SIP headers are located at the beginning of a line, but
+ * may span several lines, in which case the continuation lines begin with a
+ * whitespace character. RFC 2543 allows lines to be terminated with CR, LF or
+ * CRLF, RFC 3261 allows only CRLF, we support both.
+ *
+ * Headers are followed by (optionally) whitespace, a colon, again (optionally)
+ * 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 separated list of values is
+ * equivalent to multiple headers.
+ */
+static const struct sip_header ct_sip_hdrs[] = {
+ [SIP_HDR_CSEQ] = SIP_HDR("CSeq", NULL, NULL, digits_len),
+ [SIP_HDR_FROM] = SIP_HDR("From", "f", "sip:", skp_epaddr_len),
+ [SIP_HDR_TO] = SIP_HDR("To", "t", "sip:", skp_epaddr_len),
+ [SIP_HDR_CONTACT] = SIP_HDR("Contact", "m", "sip:", skp_epaddr_len),
+ [SIP_HDR_VIA_UDP] = SIP_HDR("Via", "v", "UDP ", epaddr_len),
+ [SIP_HDR_VIA_TCP] = SIP_HDR("Via", "v", "TCP ", epaddr_len),
+ [SIP_HDR_EXPIRES] = SIP_HDR("Expires", NULL, NULL, digits_len),
+ [SIP_HDR_CONTENT_LENGTH] = SIP_HDR("Content-Length", "l", NULL, digits_len),
+};
+
+static const char *sip_follow_continuation(const char *dptr, const char *limit)
+{
+ /* Walk past newline */
+ if (++dptr >= limit)
+ return NULL;
+
+ /* Skip '\n' in CR LF */
+ if (*(dptr - 1) == '\r' && *dptr == '\n') {
+ if (++dptr >= limit)
+ return NULL;
+ }
+
+ /* Continuation line? */
+ if (*dptr != ' ' && *dptr != '\t')
+ return NULL;
+
+ /* skip leading whitespace */
+ for (; dptr < limit; dptr++) {
+ if (*dptr != ' ' && *dptr != '\t')
+ break;
+ }
+ return dptr;
+}
+
+static const char *sip_skip_whitespace(const char *dptr, const char *limit)
+{
+ for (; dptr < limit; dptr++) {
+ if (*dptr == ' ')
+ continue;
+ if (*dptr != '\r' && *dptr != '\n')
+ break;
+ dptr = sip_follow_continuation(dptr, limit);
+ if (dptr == NULL)
+ return NULL;
+ }
+ return dptr;
+}
+
+/* Search within a SIP header value, dealing with continuation lines */
+static const char *ct_sip_header_search(const char *dptr, const char *limit,
+ const char *needle, unsigned int len)
+{
+ for (limit -= len; dptr < limit; dptr++) {
+ if (*dptr == '\r' || *dptr == '\n') {
+ dptr = sip_follow_continuation(dptr, limit);
+ if (dptr == NULL)
+ break;
+ continue;
+ }
+
+ if (strnicmp(dptr, needle, len) == 0)
+ return dptr;
+ }
+ return NULL;
+}
+
+int ct_sip_get_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;
+
+ for (dptr += dataoff; dptr < limit; dptr++) {
+ /* Find beginning of line */
+ if (*dptr != '\r' && *dptr != '\n')
+ continue;
+ if (++dptr >= limit)
+ break;
+ if (*(dptr - 1) == '\r' && *dptr == '\n') {
+ if (++dptr >= limit)
+ break;
}
- aux += hnfo->ln_strlen;
- *matchlen = hnfo->match_len(ct, aux, limit, &shift);
+ /* Skip continuation lines */
+ if (*dptr == ' ' || *dptr == '\t')
+ continue;
+
+ /* Find header. Compact headers must be followed by a
+ * non-alphabetic character to avoid mismatches. */
+ if (limit - dptr >= hdr->len &&
+ strnicmp(dptr, hdr->name, hdr->len) == 0)
+ dptr += hdr->len;
+ else if (hdr->cname && limit - dptr >= hdr->clen + 1 &&
+ strnicmp(dptr, hdr->cname, hdr->clen) == 0 &&
+ !isalpha(*(dptr + hdr->clen)))
+ dptr += hdr->clen;
+ else
+ continue;
+
+ /* Find and skip colon */
+ dptr = sip_skip_whitespace(dptr, limit);
+ if (dptr == NULL)
+ break;
+ if (*dptr != ':' || ++dptr >= limit)
+ break;
+
+ /* Skip whitespace after colon */
+ dptr = sip_skip_whitespace(dptr, limit);
+ if (dptr == NULL)
+ break;
+
+ *matchoff = dptr - start;
+ if (hdr->search) {
+ dptr = ct_sip_header_search(dptr, limit, hdr->search,
+ hdr->slen);
+ if (!dptr)
+ return -1;
+ dptr += hdr->slen;
+ }
+
+ *matchlen = hdr->match_len(ct, dptr, limit, &shift);
if (!*matchlen)
return -1;
+ *matchoff = dptr - start + shift;
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ct_sip_get_header);
+
+/* Get next header field in a list of comma separated 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;
- *matchoff = (aux - k) + shift;
+ dptr = ct_sip_header_search(dptr, limit, ",", strlen(","));
+ if (!dptr)
+ return 0;
- DEBUGP("%s match succeeded! - len: %u\n", hnfo->lname,
- *matchlen);
+ 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);
+
+static int ct_sip_parse_param(const struct nf_conn *ct, const char *dptr,
+ unsigned int dataoff, unsigned int datalen,
+ const char *name,
+ unsigned int *matchoff, unsigned int *matchlen)
+{
+ const char *limit = dptr + datalen;
+ const char *start;
+ const 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);
+
+ end = ct_sip_header_search(start, limit, ";", strlen(";"));
+ if (!end)
+ end = limit;
+
+ *matchoff = start - dptr;
+ *matchlen = end - start;
+ return 1;
+}
+
+/* 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);
+
+static int ct_sip_parse_transport(struct nf_conn *ct, const char *dptr,
+ unsigned int dataoff, unsigned int datalen,
+ u8 *proto)
+{
+ unsigned int matchoff, matchlen;
+
+ if (ct_sip_parse_param(ct, dptr, dataoff, datalen, "transport=",
+ &matchoff, &matchlen)) {
+ if (!strnicmp(dptr + matchoff, "TCP", strlen("TCP")))
+ *proto = IPPROTO_TCP;
+ else if (!strnicmp(dptr + matchoff, "UDP", strlen("UDP")))
+ *proto = IPPROTO_UDP;
+ else
+ return 0;
+
+ if (*proto != nf_ct_protonum(ct))
+ return 0;
+ } else
+ *proto = nf_ct_protonum(ct);
+
+ return 1;
+}
+
+/* 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.
+ *
+ * SDP headers always start at the beginning of a line. According to RFC 2327:
+ * "The sequence CRLF (0x0d0a) is used to end a record, although parsers should
+ * be tolerant and also accept records terminated with a single newline
+ * character". We handle both cases.
+ */
+static const struct sip_header ct_sdp_hdrs[] = {
+ [SDP_HDR_VERSION] = SDP_HDR("v=", NULL, digits_len),
+ [SDP_HDR_OWNER_IP4] = SDP_HDR("o=", "IN IP4 ", epaddr_len),
+ [SDP_HDR_CONNECTION_IP4] = SDP_HDR("c=", "IN IP4 ", epaddr_len),
+ [SDP_HDR_OWNER_IP6] = SDP_HDR("o=", "IN IP6 ", epaddr_len),
+ [SDP_HDR_CONNECTION_IP6] = SDP_HDR("c=", "IN IP6 ", epaddr_len),
+ [SDP_HDR_MEDIA] = SDP_HDR("m=", NULL, media_len),
+};
+
+/* Linear string search within SDP header values */
+static const char *ct_sdp_header_search(const char *dptr, const char *limit,
+ const char *needle, unsigned int len)
+{
+ for (limit -= len; dptr < limit; dptr++) {
+ if (*dptr == '\r' || *dptr == '\n')
+ break;
+ if (strncmp(dptr, needle, len) == 0)
+ return dptr;
+ }
+ return NULL;
+}
+
+/* Locate a SDP header (optionally a substring within the header value),
+ * optionally stopping at the first occurence of the term header, parse
+ * it and return the offset and length of the data we're interested in.
+ */
+int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr,
+ unsigned int dataoff, unsigned int datalen,
+ enum sdp_header_types type,
+ enum sdp_header_types term,
+ unsigned int *matchoff, unsigned int *matchlen)
+{
+ const struct sip_header *hdr = &ct_sdp_hdrs[type];
+ const struct sip_header *thdr = &ct_sdp_hdrs[term];
+ const char *start = dptr, *limit = dptr + datalen;
+ int shift = 0;
+
+ for (dptr += dataoff; dptr < limit; dptr++) {
+ /* Find beginning of line */
+ if (*dptr != '\r' && *dptr != '\n')
+ continue;
+ if (++dptr >= limit)
+ break;
+ if (*(dptr - 1) == '\r' && *dptr == '\n') {
+ if (++dptr >= limit)
+ break;
+ }
+
+ if (term != SDP_HDR_UNSPEC &&
+ limit - dptr >= thdr->len &&
+ strnicmp(dptr, thdr->name, thdr->len) == 0)
+ break;
+ else if (limit - dptr >= hdr->len &&
+ strnicmp(dptr, hdr->name, hdr->len) == 0)
+ dptr += hdr->len;
+ else
+ continue;
+
+ *matchoff = dptr - start;
+ if (hdr->search) {
+ dptr = ct_sdp_header_search(dptr, limit, hdr->search,
+ hdr->slen);
+ if (!dptr)
+ return -1;
+ dptr += hdr->slen;
+ }
+
+ *matchlen = hdr->match_len(ct, dptr, limit, &shift);
+ if (!*matchlen)
+ return -1;
+ *matchoff = dptr - start + shift;
return 1;
}
- DEBUGP("%s header not found.\n", hnfo->lname);
return 0;
}
-EXPORT_SYMBOL_GPL(ct_sip_get_info);
+EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header);
+
+static int ct_sip_parse_sdp_addr(const struct nf_conn *ct, const char *dptr,
+ unsigned int dataoff, unsigned int datalen,
+ enum sdp_header_types type,
+ enum sdp_header_types term,
+ unsigned int *matchoff, unsigned int *matchlen,
+ union nf_inet_addr *addr)
+{
+ int ret;
+
+ ret = ct_sip_get_sdp_header(ct, dptr, dataoff, datalen, type, term,
+ matchoff, matchlen);
+ if (ret <= 0)
+ return ret;
+
+ if (!parse_addr(ct, dptr + *matchoff, NULL, addr,
+ dptr + *matchoff + *matchlen))
+ return -1;
+ return 1;
+}
-static int set_expected_rtp(struct sk_buff **pskb,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo,
- union nf_conntrack_address *addr,
- __be16 port,
- const char *dptr)
+static int refresh_signalling_expectation(struct nf_conn *ct,
+ union nf_inet_addr *addr,
+ u8 proto, __be16 port,
+ unsigned int expires)
{
+ struct nf_conn_help *help = nfct_help(ct);
struct nf_conntrack_expect *exp;
+ struct hlist_node *n, *next;
+ int found = 0;
+
+ spin_lock_bh(&nf_conntrack_lock);
+ hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
+ if (exp->class != SIP_EXPECT_SIGNALLING ||
+ !nf_inet_addr_cmp(&exp->tuple.dst.u3, addr) ||
+ exp->tuple.dst.protonum != proto ||
+ exp->tuple.dst.u.udp.port != port)
+ continue;
+ if (!del_timer(&exp->timeout))
+ continue;
+ exp->flags &= ~NF_CT_EXPECT_INACTIVE;
+ exp->timeout.expires = jiffies + expires * HZ;
+ add_timer(&exp->timeout);
+ found = 1;
+ break;
+ }
+ spin_unlock_bh(&nf_conntrack_lock);
+ return found;
+}
+
+static void flush_expectations(struct nf_conn *ct, bool media)
+{
+ struct nf_conn_help *help = nfct_help(ct);
+ struct nf_conntrack_expect *exp;
+ struct hlist_node *n, *next;
+
+ spin_lock_bh(&nf_conntrack_lock);
+ hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
+ if ((exp->class != SIP_EXPECT_SIGNALLING) ^ media)
+ continue;
+ if (!del_timer(&exp->timeout))
+ continue;
+ nf_ct_unlink_expect(exp);
+ nf_ct_expect_put(exp);
+ if (!media)
+ break;
+ }
+ spin_unlock_bh(&nf_conntrack_lock);
+}
+
+static int set_expected_rtp_rtcp(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ union nf_inet_addr *daddr, __be16 port,
+ enum sip_expectation_classes class,
+ unsigned int mediaoff, unsigned int medialen)
+{
+ struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp;
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct net *net = nf_ct_net(ct);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
- int family = ct->tuplehash[!dir].tuple.src.l3num;
+ union nf_inet_addr *saddr;
+ struct nf_conntrack_tuple tuple;
+ int direct_rtp = 0, skip_expect = 0, ret = NF_DROP;
+ u_int16_t base_port;
+ __be16 rtp_port, rtcp_port;
+ typeof(nf_nat_sdp_port_hook) nf_nat_sdp_port;
+ typeof(nf_nat_sdp_media_hook) nf_nat_sdp_media;
+
+ saddr = NULL;
+ if (sip_direct_media) {
+ if (!nf_inet_addr_cmp(daddr, &ct->tuplehash[dir].tuple.src.u3))
+ return NF_ACCEPT;
+ saddr = &ct->tuplehash[!dir].tuple.src.u3;
+ }
+
+ /* We need to check whether the registration exists before attempting
+ * to register it since we can see the same media description multiple
+ * times on different connections in case multiple endpoints receive
+ * the same call.
+ *
+ * RTP optimization: if we find a matching media channel expectation
+ * and both the expectation and this connection are SNATed, we assume
+ * both sides can reach each other directly and use the final
+ * destination address from the expectation. We still need to keep
+ * the NATed expectations for media that might arrive from the
+ * outside, and additionally need to expect the direct RTP stream
+ * in case it passes through us even without NAT.
+ */
+ memset(&tuple, 0, sizeof(tuple));
+ if (saddr)
+ tuple.src.u3 = *saddr;
+ tuple.src.l3num = nf_ct_l3num(ct);
+ tuple.dst.protonum = IPPROTO_UDP;
+ tuple.dst.u3 = *daddr;
+ tuple.dst.u.udp.port = port;
+
+ rcu_read_lock();
+ do {
+ exp = __nf_ct_expect_find(net, nf_ct_zone(ct), &tuple);
+
+ if (!exp || exp->master == ct ||
+ nfct_help(exp->master)->helper != nfct_help(ct)->helper ||
+ exp->class != class)
+ break;
+#ifdef CONFIG_NF_NAT_NEEDED
+ if (exp->tuple.src.l3num == AF_INET && !direct_rtp &&
+ (exp->saved_ip != exp->tuple.dst.u3.ip ||
+ exp->saved_proto.udp.port != exp->tuple.dst.u.udp.port) &&
+ ct->status & IPS_NAT_MASK) {
+ daddr->ip = exp->saved_ip;
+ tuple.dst.u3.ip = exp->saved_ip;
+ tuple.dst.u.udp.port = exp->saved_proto.udp.port;
+ direct_rtp = 1;
+ } else
+#endif
+ skip_expect = 1;
+ } while (!skip_expect);
+ rcu_read_unlock();
+
+ base_port = ntohs(tuple.dst.u.udp.port) & ~1;
+ rtp_port = htons(base_port);
+ rtcp_port = htons(base_port + 1);
+
+ if (direct_rtp) {
+ nf_nat_sdp_port = rcu_dereference(nf_nat_sdp_port_hook);
+ if (nf_nat_sdp_port &&
+ !nf_nat_sdp_port(skb, dataoff, dptr, datalen,
+ mediaoff, medialen, ntohs(rtp_port)))
+ goto err1;
+ }
+
+ if (skip_expect)
+ return NF_ACCEPT;
+
+ rtp_exp = nf_ct_expect_alloc(ct);
+ if (rtp_exp == NULL)
+ goto err1;
+ nf_ct_expect_init(rtp_exp, class, nf_ct_l3num(ct), saddr, daddr,
+ IPPROTO_UDP, NULL, &rtp_port);
+
+ rtcp_exp = nf_ct_expect_alloc(ct);
+ if (rtcp_exp == NULL)
+ goto err2;
+ nf_ct_expect_init(rtcp_exp, class, nf_ct_l3num(ct), saddr, daddr,
+ IPPROTO_UDP, NULL, &rtcp_port);
+
+ nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook);
+ if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK && !direct_rtp)
+ ret = nf_nat_sdp_media(skb, dataoff, dptr, datalen,
+ rtp_exp, rtcp_exp,
+ mediaoff, medialen, daddr);
+ else {
+ if (nf_ct_expect_related(rtp_exp) == 0) {
+ if (nf_ct_expect_related(rtcp_exp) != 0)
+ nf_ct_unexpect_related(rtp_exp);
+ else
+ ret = NF_ACCEPT;
+ }
+ }
+ nf_ct_expect_put(rtcp_exp);
+err2:
+ nf_ct_expect_put(rtp_exp);
+err1:
+ return ret;
+}
+
+static const struct sdp_media_type sdp_media_types[] = {
+ SDP_MEDIA_TYPE("audio ", SIP_EXPECT_AUDIO),
+ SDP_MEDIA_TYPE("video ", SIP_EXPECT_VIDEO),
+ SDP_MEDIA_TYPE("image ", SIP_EXPECT_IMAGE),
+};
+
+static const struct sdp_media_type *sdp_media_type(const char *dptr,
+ unsigned int matchoff,
+ unsigned int matchlen)
+{
+ const struct sdp_media_type *t;
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(sdp_media_types); i++) {
+ t = &sdp_media_types[i];
+ if (matchlen < t->len ||
+ strncmp(dptr + matchoff, t->name, t->len))
+ continue;
+ return t;
+ }
+ return NULL;
+}
+
+static int process_sdp(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchoff, matchlen;
+ unsigned int mediaoff, medialen;
+ unsigned int sdpoff;
+ unsigned int caddr_len, maddr_len;
+ unsigned int i;
+ union nf_inet_addr caddr, maddr, rtp_addr;
+ unsigned int port;
+ enum sdp_header_types c_hdr;
+ const struct sdp_media_type *t;
+ int ret = NF_ACCEPT;
+ typeof(nf_nat_sdp_addr_hook) nf_nat_sdp_addr;
+ typeof(nf_nat_sdp_session_hook) nf_nat_sdp_session;
+
+ nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook);
+ c_hdr = nf_ct_l3num(ct) == AF_INET ? SDP_HDR_CONNECTION_IP4 :
+ SDP_HDR_CONNECTION_IP6;
+
+ /* Find beginning of session description */
+ if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen,
+ SDP_HDR_VERSION, SDP_HDR_UNSPEC,
+ &matchoff, &matchlen) <= 0)
+ return NF_ACCEPT;
+ sdpoff = matchoff;
+
+ /* The connection information is contained in the session description
+ * and/or once per media description. The first media description marks
+ * the end of the session description. */
+ caddr_len = 0;
+ if (ct_sip_parse_sdp_addr(ct, *dptr, sdpoff, *datalen,
+ c_hdr, SDP_HDR_MEDIA,
+ &matchoff, &matchlen, &caddr) > 0)
+ caddr_len = matchlen;
+
+ mediaoff = sdpoff;
+ for (i = 0; i < ARRAY_SIZE(sdp_media_types); ) {
+ if (ct_sip_get_sdp_header(ct, *dptr, mediaoff, *datalen,
+ SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
+ &mediaoff, &medialen) <= 0)
+ break;
+
+ /* Get media type and port number. A media port value of zero
+ * indicates an inactive stream. */
+ t = sdp_media_type(*dptr, mediaoff, medialen);
+ if (!t) {
+ mediaoff += medialen;
+ continue;
+ }
+ mediaoff += t->len;
+ medialen -= t->len;
+
+ port = simple_strtoul(*dptr + mediaoff, NULL, 10);
+ if (port == 0)
+ continue;
+ if (port < 1024 || port > 65535)
+ return NF_DROP;
+
+ /* The media description overrides the session description. */
+ maddr_len = 0;
+ if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen,
+ c_hdr, SDP_HDR_MEDIA,
+ &matchoff, &matchlen, &maddr) > 0) {
+ maddr_len = matchlen;
+ memcpy(&rtp_addr, &maddr, sizeof(rtp_addr));
+ } else if (caddr_len)
+ memcpy(&rtp_addr, &caddr, sizeof(rtp_addr));
+ else
+ return NF_DROP;
+
+ ret = set_expected_rtp_rtcp(skb, dataoff, dptr, datalen,
+ &rtp_addr, htons(port), t->class,
+ mediaoff, medialen);
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ /* Update media connection address if present */
+ if (maddr_len && nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) {
+ ret = nf_nat_sdp_addr(skb, dataoff, dptr, datalen,
+ mediaoff, c_hdr, SDP_HDR_MEDIA,
+ &rtp_addr);
+ if (ret != NF_ACCEPT)
+ return ret;
+ }
+ i++;
+ }
+
+ /* Update session connection and owner addresses */
+ nf_nat_sdp_session = rcu_dereference(nf_nat_sdp_session_hook);
+ if (nf_nat_sdp_session && ct->status & IPS_NAT_MASK)
+ ret = nf_nat_sdp_session(skb, dataoff, dptr, datalen, sdpoff,
+ &rtp_addr);
+
+ return ret;
+}
+static int process_invite_response(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq, unsigned int code)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct nf_conn_help *help = nfct_help(ct);
+
+ if ((code >= 100 && code <= 199) ||
+ (code >= 200 && code <= 299))
+ return process_sdp(skb, dataoff, dptr, datalen, cseq);
+ else if (help->help.ct_sip_info.invite_cseq == cseq)
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+}
+
+static int process_update_response(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq, unsigned int code)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct nf_conn_help *help = nfct_help(ct);
+
+ if ((code >= 100 && code <= 199) ||
+ (code >= 200 && code <= 299))
+ return process_sdp(skb, dataoff, dptr, datalen, cseq);
+ else if (help->help.ct_sip_info.invite_cseq == cseq)
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+}
+
+static int process_prack_response(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq, unsigned int code)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct nf_conn_help *help = nfct_help(ct);
+
+ if ((code >= 100 && code <= 199) ||
+ (code >= 200 && code <= 299))
+ return process_sdp(skb, dataoff, dptr, datalen, cseq);
+ else if (help->help.ct_sip_info.invite_cseq == cseq)
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+}
+
+static int process_invite_request(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct nf_conn_help *help = nfct_help(ct);
+ unsigned int ret;
+
+ flush_expectations(ct, true);
+ ret = process_sdp(skb, dataoff, dptr, datalen, cseq);
+ if (ret == NF_ACCEPT)
+ help->help.ct_sip_info.invite_cseq = cseq;
+ return ret;
+}
+
+static int process_bye_request(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+}
+
+/* Parse a REGISTER request and create a permanent expectation for incoming
+ * signalling connections. The expectation is marked inactive and is activated
+ * when receiving a response indicating success from the registrar.
+ */
+static int process_register_request(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct nf_conn_help *help = nfct_help(ct);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ unsigned int matchoff, matchlen;
+ struct nf_conntrack_expect *exp;
+ union nf_inet_addr *saddr, daddr;
+ __be16 port;
+ u8 proto;
+ unsigned int expires = 0;
int ret;
- typeof(nf_nat_sdp_hook) nf_nat_sdp;
+ typeof(nf_nat_sip_expect_hook) nf_nat_sip_expect;
+
+ /* Expected connections can not register again. */
+ if (ct->status & IPS_EXPECTED)
+ return NF_ACCEPT;
+
+ /* We must check the expiration time: a value of zero signals the
+ * registrar to release the binding. We'll remove our expectation
+ * when receiving the new bindings in the response, but we don't
+ * want to create new ones.
+ *
+ * The expiration time may be contained in Expires: header, the
+ * Contact: header parameters or the URI parameters.
+ */
+ if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
+ &matchoff, &matchlen) > 0)
+ expires = simple_strtoul(*dptr + matchoff, NULL, 10);
+
+ ret = ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
+ SIP_HDR_CONTACT, NULL,
+ &matchoff, &matchlen, &daddr, &port);
+ if (ret < 0)
+ return NF_DROP;
+ else if (ret == 0)
+ return NF_ACCEPT;
+
+ /* We don't support third-party registrations */
+ if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, &daddr))
+ return NF_ACCEPT;
+
+ if (ct_sip_parse_transport(ct, *dptr, matchoff + matchlen, *datalen,
+ &proto) == 0)
+ return NF_ACCEPT;
+
+ if (ct_sip_parse_numerical_param(ct, *dptr,
+ matchoff + matchlen, *datalen,
+ "expires=", NULL, NULL, &expires) < 0)
+ return NF_DROP;
+
+ if (expires == 0) {
+ ret = NF_ACCEPT;
+ goto store_cseq;
+ }
exp = nf_ct_expect_alloc(ct);
- if (exp == NULL)
+ if (!exp)
return NF_DROP;
- nf_ct_expect_init(exp, family,
- &ct->tuplehash[!dir].tuple.src.u3, addr,
- IPPROTO_UDP, NULL, &port);
- nf_nat_sdp = rcu_dereference(nf_nat_sdp_hook);
- if (nf_nat_sdp && ct->status & IPS_NAT_MASK)
- ret = nf_nat_sdp(pskb, ctinfo, exp, dptr);
+ saddr = NULL;
+ if (sip_direct_signalling)
+ saddr = &ct->tuplehash[!dir].tuple.src.u3;
+
+ nf_ct_expect_init(exp, SIP_EXPECT_SIGNALLING, nf_ct_l3num(ct),
+ saddr, &daddr, proto, NULL, &port);
+ exp->timeout.expires = sip_timeout * HZ;
+ exp->helper = nfct_help(ct)->helper;
+ exp->flags = NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE;
+
+ nf_nat_sip_expect = rcu_dereference(nf_nat_sip_expect_hook);
+ if (nf_nat_sip_expect && ct->status & IPS_NAT_MASK)
+ ret = nf_nat_sip_expect(skb, dataoff, dptr, datalen, exp,
+ matchoff, matchlen);
else {
if (nf_ct_expect_related(exp) != 0)
ret = NF_DROP;
}
nf_ct_expect_put(exp);
+store_cseq:
+ if (ret == NF_ACCEPT)
+ help->help.ct_sip_info.register_cseq = cseq;
return ret;
}
-static int sip_help(struct sk_buff **pskb,
- unsigned int protoff,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo)
+static int process_register_response(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int cseq, unsigned int code)
{
- int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
- union nf_conntrack_address addr;
- unsigned int dataoff, datalen;
- const char *dptr;
- int ret = NF_ACCEPT;
- int matchoff, matchlen;
- u_int16_t port;
- enum sip_header_pos pos;
- typeof(nf_nat_sip_hook) nf_nat_sip;
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct nf_conn_help *help = nfct_help(ct);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ union nf_inet_addr addr;
+ __be16 port;
+ u8 proto;
+ unsigned int matchoff, matchlen, coff = 0;
+ unsigned int expires = 0;
+ int in_contact = 0, ret;
- /* No Data ? */
- dataoff = protoff + sizeof(struct udphdr);
- if (dataoff >= (*pskb)->len)
+ /* According to RFC 3261, "UAs MUST NOT send a new registration until
+ * they have received a final response from the registrar for the
+ * previous one or the previous REGISTER request has timed out".
+ *
+ * However, some servers fail to detect retransmissions and send late
+ * responses, so we store the sequence number of the last valid
+ * request and compare it here.
+ */
+ if (help->help.ct_sip_info.register_cseq != cseq)
+ return NF_ACCEPT;
+
+ if (code >= 100 && code <= 199)
return NF_ACCEPT;
+ if (code < 200 || code > 299)
+ goto flush;
- nf_ct_refresh(ct, *pskb, sip_timeout * HZ);
+ if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
+ &matchoff, &matchlen) > 0)
+ expires = simple_strtoul(*dptr + matchoff, NULL, 10);
- if (!skb_is_nonlinear(*pskb))
- dptr = (*pskb)->data + dataoff;
- else {
- DEBUGP("Copy of skbuff not supported yet.\n");
- goto out;
+ while (1) {
+ unsigned int c_expires = expires;
+
+ ret = ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen,
+ SIP_HDR_CONTACT, &in_contact,
+ &matchoff, &matchlen,
+ &addr, &port);
+ if (ret < 0)
+ return NF_DROP;
+ else if (ret == 0)
+ break;
+
+ /* We don't support third-party registrations */
+ if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, &addr))
+ continue;
+
+ if (ct_sip_parse_transport(ct, *dptr, matchoff + matchlen,
+ *datalen, &proto) == 0)
+ continue;
+
+ ret = ct_sip_parse_numerical_param(ct, *dptr,
+ matchoff + matchlen,
+ *datalen, "expires=",
+ NULL, NULL, &c_expires);
+ if (ret < 0)
+ return NF_DROP;
+ if (c_expires == 0)
+ break;
+ if (refresh_signalling_expectation(ct, &addr, proto, port,
+ c_expires))
+ return NF_ACCEPT;
}
- nf_nat_sip = rcu_dereference(nf_nat_sip_hook);
- if (nf_nat_sip && ct->status & IPS_NAT_MASK) {
- if (!nf_nat_sip(pskb, ctinfo, ct, &dptr)) {
- ret = NF_DROP;
- goto out;
- }
+flush:
+ flush_expectations(ct, false);
+ return NF_ACCEPT;
+}
+
+static const struct sip_handler sip_handlers[] = {
+ SIP_HANDLER("INVITE", process_invite_request, process_invite_response),
+ SIP_HANDLER("UPDATE", process_sdp, process_update_response),
+ SIP_HANDLER("ACK", process_sdp, NULL),
+ SIP_HANDLER("PRACK", process_sdp, process_prack_response),
+ SIP_HANDLER("BYE", process_bye_request, NULL),
+ SIP_HANDLER("REGISTER", process_register_request, process_register_response),
+};
+
+static int process_sip_response(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchoff, matchlen, matchend;
+ unsigned int code, cseq, i;
+
+ if (*datalen < strlen("SIP/2.0 200"))
+ return NF_ACCEPT;
+ code = simple_strtoul(*dptr + strlen("SIP/2.0 "), NULL, 10);
+ if (!code)
+ return NF_DROP;
+
+ if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ,
+ &matchoff, &matchlen) <= 0)
+ return NF_DROP;
+ cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
+ if (!cseq)
+ return NF_DROP;
+ matchend = matchoff + matchlen + 1;
+
+ for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) {
+ const struct sip_handler *handler;
+
+ handler = &sip_handlers[i];
+ if (handler->response == NULL)
+ continue;
+ if (*datalen < matchend + handler->len ||
+ strnicmp(*dptr + matchend, handler->method, handler->len))
+ continue;
+ return handler->response(skb, dataoff, dptr, datalen,
+ cseq, code);
}
+ return NF_ACCEPT;
+}
+
+static int process_sip_request(struct sk_buff *skb, unsigned int dataoff,
+ const char **dptr, unsigned int *datalen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchoff, matchlen;
+ unsigned int cseq, i;
+
+ for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) {
+ const struct sip_handler *handler;
+
+ handler = &sip_handlers[i];
+ if (handler->request == NULL)
+ continue;
+ if (*datalen < handler->len ||
+ strnicmp(*dptr, handler->method, handler->len))
+ continue;
- datalen = (*pskb)->len - dataoff;
- if (datalen < sizeof("SIP/2.0 200") - 1)
- goto out;
+ if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ,
+ &matchoff, &matchlen) <= 0)
+ return NF_DROP;
+ cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
+ if (!cseq)
+ return NF_DROP;
- /* RTP info only in some SDP pkts */
- if (memcmp(dptr, "INVITE", sizeof("INVITE") - 1) != 0 &&
- memcmp(dptr, "UPDATE", sizeof("UPDATE") - 1) != 0 &&
- memcmp(dptr, "SIP/2.0 180", sizeof("SIP/2.0 180") - 1) != 0 &&
- memcmp(dptr, "SIP/2.0 183", sizeof("SIP/2.0 183") - 1) != 0 &&
- memcmp(dptr, "SIP/2.0 200", sizeof("SIP/2.0 200") - 1) != 0) {
- goto out;
+ return handler->request(skb, dataoff, dptr, datalen, cseq);
}
- /* Get address and port from SDP packet. */
- pos = family == AF_INET ? POS_CONNECTION_IP4 : POS_CONNECTION_IP6;
- if (ct_sip_get_info(ct, dptr, datalen, &matchoff, &matchlen, pos) > 0) {
+ return NF_ACCEPT;
+}
- /* We'll drop only if there are parse problems. */
- if (!parse_addr(ct, dptr + matchoff, NULL, &addr,
- dptr + datalen)) {
+static int process_sip_msg(struct sk_buff *skb, struct nf_conn *ct,
+ unsigned int dataoff, const char **dptr,
+ unsigned int *datalen)
+{
+ typeof(nf_nat_sip_hook) nf_nat_sip;
+ int ret;
+
+ if (strnicmp(*dptr, "SIP/2.0 ", strlen("SIP/2.0 ")) != 0)
+ ret = process_sip_request(skb, dataoff, dptr, datalen);
+ else
+ ret = process_sip_response(skb, dataoff, dptr, datalen);
+
+ if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) {
+ nf_nat_sip = rcu_dereference(nf_nat_sip_hook);
+ if (nf_nat_sip && !nf_nat_sip(skb, dataoff, dptr, datalen))
ret = NF_DROP;
- goto out;
- }
- if (ct_sip_get_info(ct, dptr, datalen, &matchoff, &matchlen,
- POS_MEDIA) > 0) {
+ }
- port = simple_strtoul(dptr + matchoff, NULL, 10);
- if (port < 1024) {
- ret = NF_DROP;
- goto out;
- }
- ret = set_expected_rtp(pskb, ct, ctinfo, &addr,
- htons(port), dptr);
- }
+ return ret;
+}
+
+static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff,
+ struct nf_conn *ct, enum ip_conntrack_info ctinfo)
+{
+ struct tcphdr *th, _tcph;
+ unsigned int dataoff, datalen;
+ unsigned int matchoff, matchlen, clen;
+ unsigned int msglen, origlen;
+ const char *dptr, *end;
+ s16 diff, tdiff = 0;
+ int ret;
+ typeof(nf_nat_sip_seq_adjust_hook) nf_nat_sip_seq_adjust;
+
+ if (ctinfo != IP_CT_ESTABLISHED &&
+ ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY)
+ return NF_ACCEPT;
+
+ /* No Data ? */
+ th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
+ if (th == NULL)
+ return NF_ACCEPT;
+ dataoff = protoff + th->doff * 4;
+ if (dataoff >= skb->len)
+ return NF_ACCEPT;
+
+ nf_ct_refresh(ct, skb, sip_timeout * HZ);
+
+ if (skb_is_nonlinear(skb)) {
+ pr_debug("Copy of skbuff not supported yet.\n");
+ return NF_ACCEPT;
}
-out:
+
+ dptr = skb->data + dataoff;
+ datalen = skb->len - dataoff;
+ if (datalen < strlen("SIP/2.0 200"))
+ return NF_ACCEPT;
+
+ while (1) {
+ if (ct_sip_get_header(ct, dptr, 0, datalen,
+ SIP_HDR_CONTENT_LENGTH,
+ &matchoff, &matchlen) <= 0)
+ break;
+
+ clen = simple_strtoul(dptr + matchoff, (char **)&end, 10);
+ if (dptr + matchoff == end)
+ break;
+
+ if (end + strlen("\r\n\r\n") > dptr + datalen)
+ break;
+ if (end[0] != '\r' || end[1] != '\n' ||
+ end[2] != '\r' || end[3] != '\n')
+ break;
+ end += strlen("\r\n\r\n") + clen;
+
+ msglen = origlen = end - dptr;
+
+ ret = process_sip_msg(skb, ct, dataoff, &dptr, &msglen);
+ if (ret != NF_ACCEPT)
+ break;
+ diff = msglen - origlen;
+ tdiff += diff;
+
+ dataoff += msglen;
+ dptr += msglen;
+ datalen = datalen + diff - msglen;
+ }
+
+ if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) {
+ nf_nat_sip_seq_adjust = rcu_dereference(nf_nat_sip_seq_adjust_hook);
+ if (nf_nat_sip_seq_adjust)
+ nf_nat_sip_seq_adjust(skb, tdiff);
+ }
+
return ret;
}
-static struct nf_conntrack_helper sip[MAX_PORTS][2] __read_mostly;
-static char sip_names[MAX_PORTS][2][sizeof("sip-65535")] __read_mostly;
+static int sip_help_udp(struct sk_buff *skb, unsigned int protoff,
+ struct nf_conn *ct, enum ip_conntrack_info ctinfo)
+{
+ unsigned int dataoff, datalen;
+ const char *dptr;
+
+ /* No Data ? */
+ dataoff = protoff + sizeof(struct udphdr);
+ if (dataoff >= skb->len)
+ return NF_ACCEPT;
+
+ nf_ct_refresh(ct, skb, sip_timeout * HZ);
+
+ if (skb_is_nonlinear(skb)) {
+ pr_debug("Copy of skbuff not supported yet.\n");
+ return NF_ACCEPT;
+ }
+
+ dptr = skb->data + dataoff;
+ datalen = skb->len - dataoff;
+ if (datalen < strlen("SIP/2.0 200"))
+ return NF_ACCEPT;
+
+ return process_sip_msg(skb, ct, dataoff, &dptr, &datalen);
+}
+
+static struct nf_conntrack_helper sip[MAX_PORTS][4] __read_mostly;
+static char sip_names[MAX_PORTS][4][sizeof("sip-65535")] __read_mostly;
+
+static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1] = {
+ [SIP_EXPECT_SIGNALLING] = {
+ .name = "signalling",
+ .max_expected = 1,
+ .timeout = 3 * 60,
+ },
+ [SIP_EXPECT_AUDIO] = {
+ .name = "audio",
+ .max_expected = 2 * IP_CT_DIR_MAX,
+ .timeout = 3 * 60,
+ },
+ [SIP_EXPECT_VIDEO] = {
+ .name = "video",
+ .max_expected = 2 * IP_CT_DIR_MAX,
+ .timeout = 3 * 60,
+ },
+ [SIP_EXPECT_IMAGE] = {
+ .name = "image",
+ .max_expected = IP_CT_DIR_MAX,
+ .timeout = 3 * 60,
+ },
+};
static void nf_conntrack_sip_fini(void)
{
int i, j;
for (i = 0; i < ports_c; i++) {
- for (j = 0; j < 2; j++) {
+ for (j = 0; j < ARRAY_SIZE(sip[i]); j++) {
if (sip[i][j].me == NULL)
continue;
nf_conntrack_helper_unregister(&sip[i][j]);
memset(&sip[i], 0, sizeof(sip[i]));
sip[i][0].tuple.src.l3num = AF_INET;
- sip[i][1].tuple.src.l3num = AF_INET6;
- for (j = 0; j < 2; j++) {
- sip[i][j].tuple.dst.protonum = IPPROTO_UDP;
+ sip[i][0].tuple.dst.protonum = IPPROTO_UDP;
+ sip[i][0].help = sip_help_udp;
+ sip[i][1].tuple.src.l3num = AF_INET;
+ sip[i][1].tuple.dst.protonum = IPPROTO_TCP;
+ sip[i][1].help = sip_help_tcp;
+
+ sip[i][2].tuple.src.l3num = AF_INET6;
+ sip[i][2].tuple.dst.protonum = IPPROTO_UDP;
+ sip[i][2].help = sip_help_udp;
+ sip[i][3].tuple.src.l3num = AF_INET6;
+ sip[i][3].tuple.dst.protonum = IPPROTO_TCP;
+ sip[i][3].help = sip_help_tcp;
+
+ for (j = 0; j < ARRAY_SIZE(sip[i]); j++) {
sip[i][j].tuple.src.u.udp.port = htons(ports[i]);
- sip[i][j].mask.src.l3num = 0xFFFF;
- sip[i][j].mask.src.u.udp.port = htons(0xFFFF);
- sip[i][j].mask.dst.protonum = 0xFF;
- sip[i][j].max_expected = 2;
- sip[i][j].timeout = 3 * 60; /* 3 minutes */
+ sip[i][j].expect_policy = sip_exp_policy;
+ sip[i][j].expect_class_max = SIP_EXPECT_MAX;
sip[i][j].me = THIS_MODULE;
- sip[i][j].help = sip_help;
tmpname = &sip_names[i][j][0];
if (ports[i] == SIP_PORT)
sprintf(tmpname, "sip-%u", i);
sip[i][j].name = tmpname;
- DEBUGP("port #%u: %u\n", i, ports[i]);
+ pr_debug("port #%u: %u\n", i, ports[i]);
ret = nf_conntrack_helper_register(&sip[i][j]);
if (ret) {
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff