From 0d0ab0378d67517a4f4ae3497706c13d9dd24af1 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 25 Mar 2008 20:26:24 -0700 Subject: [PATCH] [NETFILTER]: nf_conntrack_sip: support multiple media channels Add support for multiple media channels and use it to create expectations for video streams when present. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/linux/netfilter/nf_conntrack_sip.h | 14 +++ include/net/netfilter/nf_conntrack.h | 2 +- net/netfilter/nf_conntrack_sip.c | 121 +++++++++++++++------ 3 files changed, 105 insertions(+), 32 deletions(-) diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h index eca3ad3f28dc..71fa3eb5f485 100644 --- a/include/linux/netfilter/nf_conntrack_sip.h +++ b/include/linux/netfilter/nf_conntrack_sip.h @@ -12,10 +12,24 @@ struct nf_ct_sip_master { enum sip_expectation_classes { SIP_EXPECT_SIGNALLING, SIP_EXPECT_AUDIO, + SIP_EXPECT_VIDEO, __SIP_EXPECT_MAX }; #define SIP_EXPECT_MAX (__SIP_EXPECT_MAX - 1) +struct sdp_media_type { + const char *name; + unsigned int len; + enum sip_expectation_classes class; +}; + +#define SDP_MEDIA_TYPE(__name, __class) \ +{ \ + .name = (__name), \ + .len = sizeof(__name) - 1, \ + .class = (__class), \ +} + struct sip_handler { const char *method; unsigned int len; diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index 4a4f870d2a5e..a3567a7a6d67 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -78,7 +78,7 @@ do { \ struct nf_conntrack_helper; /* Must be kept in sync with the classes defined by helpers */ -#define NF_CT_MAX_EXPECT_CLASSES 2 +#define NF_CT_MAX_EXPECT_CLASSES 3 /* nf_conn feature for connections that have a helper */ struct nf_conn_help { diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index f929add324f3..f40a525732d1 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -112,6 +112,21 @@ static int digits_len(const struct nf_conn *ct, const char *dptr, 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) @@ -563,7 +578,7 @@ static const struct sip_header ct_sdp_hdrs[] = { [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 */ @@ -705,6 +720,7 @@ static void flush_expectations(struct nf_conn *ct, bool media) 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; @@ -743,7 +759,7 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb, exp = __nf_ct_expect_find(&tuple); if (exp && exp->master != ct && nfct_help(exp->master)->helper == nfct_help(ct)->helper && - exp->class == SIP_EXPECT_AUDIO) + exp->class == class) skip_expect = 1; rcu_read_unlock(); @@ -757,13 +773,13 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb, rtp_exp = nf_ct_expect_alloc(ct); if (rtp_exp == NULL) goto err1; - nf_ct_expect_init(rtp_exp, SIP_EXPECT_AUDIO, family, saddr, daddr, + nf_ct_expect_init(rtp_exp, class, family, 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, SIP_EXPECT_AUDIO, family, saddr, daddr, + nf_ct_expect_init(rtcp_exp, class, family, saddr, daddr, IPPROTO_UDP, NULL, &rtcp_port); nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook); @@ -785,6 +801,28 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb, 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) @@ -796,13 +834,16 @@ static int process_sdp(struct sk_buff *skb, 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; - int ret; + 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 = family == AF_INET ? SDP_HDR_CONNECTION_IP4 : SDP_HDR_CONNECTION_IP6; @@ -822,41 +863,55 @@ static int process_sdp(struct sk_buff *skb, &matchoff, &matchlen, &caddr) > 0) caddr_len = matchlen; - if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, - SDP_HDR_MEDIA, SDP_HDR_UNSPEC, - &mediaoff, &medialen) <= 0) - return NF_ACCEPT; + 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; - port = simple_strtoul(*dptr + mediaoff, NULL, 10); - if (port < 1024 || port > 65535) - return NF_DROP; + /* 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; - /* 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; + port = simple_strtoul(*dptr + mediaoff, NULL, 10); + if (port == 0) + continue; + if (port < 1024 || port > 65535) + return NF_DROP; - ret = set_expected_rtp_rtcp(skb, dptr, datalen, &rtp_addr, htons(port), - mediaoff, medialen); - if (ret != NF_ACCEPT) - return ret; + /* 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; - /* Update media connection address if present */ - if (maddr_len) { - nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook); - if (nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) { + 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 */ @@ -1210,6 +1265,10 @@ static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1 .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)