*
* (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/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 <linux/netfilter/nf_conntrack_sip.h>
module_param(sip_timeout, uint, 0600);
MODULE_PARM_DESC(sip_timeout, "timeout for the master SIP session");
+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,
const char **dptr,
unsigned int *datalen) __read_mostly;
EXPORT_SYMBOL_GPL(nf_nat_sip_hook);
-unsigned int (*nf_nat_sdp_hook)(struct sk_buff *skb,
- const char **dptr,
- unsigned int *datalen,
- struct nf_conntrack_expect *exp) __read_mostly;
-EXPORT_SYMBOL_GPL(nf_nat_sdp_hook);
+unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb,
+ 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);
+
+unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb,
+ const char **dptr,
+ unsigned int dataoff,
+ unsigned int *datalen,
+ 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);
+
+unsigned int (*nf_nat_sdp_port_hook)(struct sk_buff *skb,
+ 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);
+
+unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb,
+ const char **dptr,
+ unsigned int dataoff,
+ unsigned int *datalen,
+ 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,
+ 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);
static int string_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
return len;
}
+/* get media type + port length */
+static int media_len(const struct nf_conn *ct, const char *dptr,
+ const char *limit, int *shift)
+{
+ int len = string_len(ct, dptr, limit, shift);
+
+ dptr += len;
+ if (dptr >= limit || *dptr != ' ')
+ return 0;
+ len++;
+ dptr++;
+
+ return len + digits_len(ct, dptr, limit, shift);
+}
+
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;
* 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] = SIP_HDR("Via", "v", "UDP ", epaddr_len),
+ [SIP_HDR_EXPIRES] = SIP_HDR("Expires", NULL, NULL, digits_len),
[SIP_HDR_CONTENT_LENGTH] = SIP_HDR("Content-Length", "l", NULL, digits_len),
};
}
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.
[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=", "audio ", digits_len),
+ [SDP_HDR_MEDIA] = SDP_HDR("m=", NULL, media_len),
};
/* Linear string search within SDP header values */
}
EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header);
-static int set_expected_rtp(struct sk_buff *skb,
- const char **dptr, unsigned int *datalen,
- union nf_inet_addr *addr, __be16 port)
+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 refresh_signalling_expectation(struct nf_conn *ct,
+ union nf_inet_addr *addr,
+ __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.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,
+ 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);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ 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(&tuple);
+
+ if (!exp || exp->master == ct ||
+ nfct_help(exp->master)->helper != nfct_help(ct)->helper ||
+ exp->class != class)
+ break;
+
+ 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
+ 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, 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, 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),
+};
+
+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,
+ 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, 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, dptr, mediaoff, datalen,
+ 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, dptr, sdpoff, datalen, &rtp_addr);
+
+ return ret;
+}
+static int process_invite_response(struct sk_buff *skb,
+ 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);
+
+ if ((code >= 100 && code <= 199) ||
+ (code >= 200 && code <= 299))
+ return process_sdp(skb, dptr, datalen, cseq);
+ else {
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+ }
+}
+
+static int process_update_response(struct sk_buff *skb,
+ 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);
+
+ if ((code >= 100 && code <= 199) ||
+ (code >= 200 && code <= 299))
+ return process_sdp(skb, dptr, datalen, cseq);
+ else {
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+ }
+}
+
+static int process_prack_response(struct sk_buff *skb,
+ 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);
+
+ if ((code >= 100 && code <= 199) ||
+ (code >= 200 && code <= 299))
+ return process_sdp(skb, dptr, datalen, cseq);
+ else {
+ flush_expectations(ct, true);
+ return NF_ACCEPT;
+ }
+}
+
+static int process_bye_request(struct sk_buff *skb,
+ 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,
+ 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);
- int family = ct->tuplehash[!dir].tuple.src.l3num;
+ unsigned int matchoff, matchlen;
+ struct nf_conntrack_expect *exp;
+ union nf_inet_addr *saddr, daddr;
+ __be16 port;
+ 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_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, NF_CT_EXPECT_CLASS_DEFAULT, 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(skb, dptr, datalen, exp);
+ 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, IPPROTO_UDP, 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, 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 process_register_response(struct sk_buff *skb,
+ 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);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ union nf_inet_addr addr;
+ __be16 port;
+ unsigned int matchoff, matchlen, dataoff = 0;
+ unsigned int expires = 0;
+ int in_contact = 0, ret;
+
+ /* 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;
+
+ if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
+ &matchoff, &matchlen) > 0)
+ expires = simple_strtoul(*dptr + matchoff, NULL, 10);
+
+ while (1) {
+ unsigned int c_expires = expires;
+
+ ret = ct_sip_parse_header_uri(ct, *dptr, &dataoff, *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;
+
+ 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, port, c_expires))
+ return NF_ACCEPT;
+ }
+
+flush:
+ flush_expectations(ct, false);
+ return NF_ACCEPT;
+}
+
+static const struct sip_handler sip_handlers[] = {
+ SIP_HANDLER("INVITE", process_sdp, 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,
+ const char **dptr, unsigned int *datalen)
+{
+ static const struct sip_handler *handler;
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchoff, matchlen;
+ unsigned int code, cseq, dataoff, 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;
+ dataoff = matchoff + matchlen + 1;
+
+ for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) {
+ handler = &sip_handlers[i];
+ if (handler->response == NULL)
+ continue;
+ if (*datalen < dataoff + handler->len ||
+ strnicmp(*dptr + dataoff, handler->method, handler->len))
+ continue;
+ return handler->response(skb, dptr, datalen, cseq, code);
+ }
+ return NF_ACCEPT;
+}
+
+static int process_sip_request(struct sk_buff *skb,
+ const char **dptr, unsigned int *datalen)
+{
+ static const struct sip_handler *handler;
+ 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++) {
+ handler = &sip_handlers[i];
+ if (handler->request == NULL)
+ continue;
+ if (*datalen < handler->len ||
+ strnicmp(*dptr, handler->method, handler->len))
+ continue;
+
+ 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;
+
+ return handler->request(skb, dptr, datalen, cseq);
+ }
+ return NF_ACCEPT;
+}
+
static int sip_help(struct sk_buff *skb,
unsigned int protoff,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
- int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
- union nf_inet_addr addr;
unsigned int dataoff, datalen;
const char *dptr;
- int ret = NF_ACCEPT;
- unsigned int matchoff, matchlen;
- u_int16_t port;
- enum sdp_header_types type;
+ int ret;
typeof(nf_nat_sip_hook) nf_nat_sip;
/* No Data ? */
dptr = skb->data + dataoff;
else {
pr_debug("Copy of skbuff not supported yet.\n");
- goto out;
- }
-
- nf_nat_sip = rcu_dereference(nf_nat_sip_hook);
- if (nf_nat_sip && ct->status & IPS_NAT_MASK) {
- if (!nf_nat_sip(skb, &dptr, &datalen)) {
- ret = NF_DROP;
- goto out;
- }
+ return NF_ACCEPT;
}
datalen = skb->len - dataoff;
if (datalen < strlen("SIP/2.0 200"))
- goto out;
-
- /* RTP info only in some SDP pkts */
- if (strnicmp(dptr, "INVITE", strlen("INVITE")) != 0 &&
- strnicmp(dptr, "UPDATE", strlen("UPDATE")) != 0 &&
- strnicmp(dptr, "SIP/2.0 180", strlen("SIP/2.0 180")) != 0 &&
- strnicmp(dptr, "SIP/2.0 183", strlen("SIP/2.0 183")) != 0 &&
- strnicmp(dptr, "SIP/2.0 200", strlen("SIP/2.0 200")) != 0) {
- goto out;
- }
- /* Get address and port from SDP packet. */
- type = family == AF_INET ? SDP_HDR_CONNECTION_IP4 :
- SDP_HDR_CONNECTION_IP6;
- if (ct_sip_get_sdp_header(ct, dptr, 0, datalen, type, SDP_HDR_UNSPEC,
- &matchoff, &matchlen) > 0) {
-
- /* We'll drop only if there are parse problems. */
- if (!parse_addr(ct, dptr + matchoff, NULL, &addr,
- dptr + datalen)) {
- ret = NF_DROP;
- goto out;
- }
- if (ct_sip_get_sdp_header(ct, dptr, 0, datalen,
- SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
- &matchoff, &matchlen) > 0) {
+ return NF_ACCEPT;
- port = simple_strtoul(dptr + matchoff, NULL, 10);
- if (port < 1024) {
- ret = NF_DROP;
- goto out;
- }
- ret = set_expected_rtp(skb, &dptr, &datalen,
- &addr, htons(port));
- }
+ if (strnicmp(dptr, "SIP/2.0 ", strlen("SIP/2.0 ")) != 0)
+ ret = process_sip_request(skb, &dptr, &datalen);
+ else
+ ret = process_sip_response(skb, &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, &dptr, &datalen))
+ ret = NF_DROP;
}
-out:
+
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 const struct nf_conntrack_expect_policy sip_exp_policy = {
- .max_expected = 2,
- .timeout = 3 * 60,
+static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1] = {
+ [SIP_EXPECT_SIGNALLING] = {
+ .max_expected = 1,
+ .timeout = 3 * 60,
+ },
+ [SIP_EXPECT_AUDIO] = {
+ .max_expected = 2 * IP_CT_DIR_MAX,
+ .timeout = 3 * 60,
+ },
+ [SIP_EXPECT_VIDEO] = {
+ .max_expected = 2 * IP_CT_DIR_MAX,
+ .timeout = 3 * 60,
+ },
};
static void nf_conntrack_sip_fini(void)
for (j = 0; j < 2; j++) {
sip[i][j].tuple.dst.protonum = IPPROTO_UDP;
sip[i][j].tuple.src.u.udp.port = htons(ports[i]);
- sip[i][j].expect_policy = &sip_exp_policy;
+ 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;
Code Review / linux-2.6.git / blobdiff