diff options
author | Patrick McHardy <kaber@trash.net> | 2010-02-11 12:26:19 +0100 |
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committer | Patrick McHardy <kaber@trash.net> | 2010-02-11 12:26:19 +0100 |
commit | f5b321bd37fbec9188feb1f721ab46a5ac0b35da (patch) | |
tree | e4899d8dcfdb4128505e4f246154934d18692295 /net/netfilter/nf_conntrack_sip.c | |
parent | 3b6b9fab42fe98358d70735cf98d43fc18dc79c9 (diff) | |
download | op-kernel-dev-f5b321bd37fbec9188feb1f721ab46a5ac0b35da.zip op-kernel-dev-f5b321bd37fbec9188feb1f721ab46a5ac0b35da.tar.gz |
netfilter: nf_conntrack_sip: add TCP support
Add TCP support, which is mandated by RFC3261 for all SIP elements.
SIP over TCP is similar to UDP, except that messages are delimited
by Content-Length: headers and multiple messages may appear in one
packet.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/netfilter/nf_conntrack_sip.c')
-rw-r--r-- | net/netfilter/nf_conntrack_sip.c | 205 |
1 files changed, 176 insertions, 29 deletions
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 0ec37d6..1cc75c5 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -16,6 +16,7 @@ #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> @@ -287,7 +288,8 @@ static const struct sip_header ct_sip_hdrs[] = { [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_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), }; @@ -519,6 +521,33 @@ int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr, } 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, @@ -577,6 +606,29 @@ int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr, } 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. @@ -685,7 +737,7 @@ static int ct_sip_parse_sdp_addr(const struct nf_conn *ct, const char *dptr, static int refresh_signalling_expectation(struct nf_conn *ct, union nf_inet_addr *addr, - __be16 port, + u8 proto, __be16 port, unsigned int expires) { struct nf_conn_help *help = nfct_help(ct); @@ -697,6 +749,7 @@ static int refresh_signalling_expectation(struct nf_conn *ct, 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)) @@ -1048,6 +1101,7 @@ static int process_register_request(struct sk_buff *skb, unsigned int dataoff, struct nf_conntrack_expect *exp; union nf_inet_addr *saddr, daddr; __be16 port; + u8 proto; unsigned int expires = 0; int ret; typeof(nf_nat_sip_expect_hook) nf_nat_sip_expect; @@ -1080,6 +1134,10 @@ static int process_register_request(struct sk_buff *skb, unsigned int dataoff, 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) @@ -1099,7 +1157,7 @@ static int process_register_request(struct sk_buff *skb, unsigned int dataoff, 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); + 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; @@ -1132,6 +1190,7 @@ static int process_register_response(struct sk_buff *skb, unsigned int dataoff, 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; @@ -1172,6 +1231,10 @@ static int process_register_response(struct sk_buff *skb, unsigned int dataoff, 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=", @@ -1180,7 +1243,8 @@ static int process_register_response(struct sk_buff *skb, unsigned int dataoff, return NF_DROP; if (c_expires == 0) break; - if (refresh_signalling_expectation(ct, &addr, port, c_expires)) + if (refresh_signalling_expectation(ct, &addr, proto, port, + c_expires)) return NF_ACCEPT; } @@ -1265,50 +1329,123 @@ static int process_sip_request(struct sk_buff *skb, unsigned int dataoff, return NF_ACCEPT; } -static int sip_help(struct sk_buff *skb, - unsigned int protoff, - struct nf_conn *ct, - enum ip_conntrack_info ctinfo) +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; + } + + 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; - const char *dptr; + unsigned int matchoff, matchlen, clen; + unsigned int msglen, origlen; + const char *dptr, *end; + s16 diff, tdiff = 0; int ret; - typeof(nf_nat_sip_hook) nf_nat_sip; + + if (ctinfo != IP_CT_ESTABLISHED && + ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) + return NF_ACCEPT; /* No Data ? */ - dataoff = protoff + sizeof(struct udphdr); + 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)) - dptr = skb->data + dataoff; - else { + 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; - 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); + while (1) { + if (ct_sip_get_header(ct, dptr, 0, datalen, + SIP_HDR_CONTENT_LENGTH, + &matchoff, &matchlen) <= 0) + break; - 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; + 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; } 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] = { @@ -1333,7 +1470,7 @@ 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]); @@ -1353,14 +1490,24 @@ static int __init nf_conntrack_sip_init(void) 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].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) |