Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1 | /* SIP extension for IP connection tracking. |
| 2 | * |
| 3 | * (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar> |
| 4 | * based on RR's ip_conntrack_ftp.c and other modules. |
Patrick McHardy | f49e1aa | 2008-03-25 20:27:05 -0700 | [diff] [blame] | 5 | * (C) 2007 United Security Providers |
| 6 | * (C) 2007, 2008 Patrick McHardy <kaber@trash.net> |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/ctype.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | #include <linux/inet.h> |
| 17 | #include <linux/in.h> |
| 18 | #include <linux/udp.h> |
Yasuyuki Kozakai | 1863f09 | 2006-12-02 22:12:54 -0800 | [diff] [blame] | 19 | #include <linux/netfilter.h> |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 20 | |
| 21 | #include <net/netfilter/nf_conntrack.h> |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 22 | #include <net/netfilter/nf_conntrack_core.h> |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 23 | #include <net/netfilter/nf_conntrack_expect.h> |
| 24 | #include <net/netfilter/nf_conntrack_helper.h> |
| 25 | #include <linux/netfilter/nf_conntrack_sip.h> |
| 26 | |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 27 | MODULE_LICENSE("GPL"); |
| 28 | MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>"); |
| 29 | MODULE_DESCRIPTION("SIP connection tracking helper"); |
| 30 | MODULE_ALIAS("ip_conntrack_sip"); |
Pablo Neira Ayuso | 4dc06f9 | 2008-11-17 16:01:42 +0100 | [diff] [blame] | 31 | MODULE_ALIAS_NFCT_HELPER("sip"); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 32 | |
| 33 | #define MAX_PORTS 8 |
| 34 | static unsigned short ports[MAX_PORTS]; |
Stephen Hemminger | 2f0d2f1 | 2008-01-31 04:08:10 -0800 | [diff] [blame] | 35 | static unsigned int ports_c; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 36 | module_param_array(ports, ushort, &ports_c, 0400); |
| 37 | MODULE_PARM_DESC(ports, "port numbers of SIP servers"); |
| 38 | |
| 39 | static unsigned int sip_timeout __read_mostly = SIP_TIMEOUT; |
| 40 | module_param(sip_timeout, uint, 0600); |
| 41 | MODULE_PARM_DESC(sip_timeout, "timeout for the master SIP session"); |
| 42 | |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 43 | static int sip_direct_signalling __read_mostly = 1; |
| 44 | module_param(sip_direct_signalling, int, 0600); |
| 45 | MODULE_PARM_DESC(sip_direct_signalling, "expect incoming calls from registrar " |
| 46 | "only (default 1)"); |
| 47 | |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 48 | static int sip_direct_media __read_mostly = 1; |
| 49 | module_param(sip_direct_media, int, 0600); |
| 50 | MODULE_PARM_DESC(sip_direct_media, "Expect Media streams between signalling " |
| 51 | "endpoints only (default 1)"); |
| 52 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 53 | unsigned int (*nf_nat_sip_hook)(struct sk_buff *skb, |
Patrick McHardy | 2a6cfb2 | 2008-03-25 20:16:54 -0700 | [diff] [blame] | 54 | const char **dptr, |
| 55 | unsigned int *datalen) __read_mostly; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 56 | EXPORT_SYMBOL_GPL(nf_nat_sip_hook); |
| 57 | |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 58 | unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb, |
| 59 | const char **dptr, |
| 60 | unsigned int *datalen, |
| 61 | struct nf_conntrack_expect *exp, |
| 62 | unsigned int matchoff, |
| 63 | unsigned int matchlen) __read_mostly; |
| 64 | EXPORT_SYMBOL_GPL(nf_nat_sip_expect_hook); |
| 65 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 66 | unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb, |
| 67 | const char **dptr, |
| 68 | unsigned int dataoff, |
| 69 | unsigned int *datalen, |
| 70 | enum sdp_header_types type, |
| 71 | enum sdp_header_types term, |
| 72 | const union nf_inet_addr *addr) |
| 73 | __read_mostly; |
| 74 | EXPORT_SYMBOL_GPL(nf_nat_sdp_addr_hook); |
| 75 | |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 76 | unsigned int (*nf_nat_sdp_port_hook)(struct sk_buff *skb, |
| 77 | const char **dptr, |
| 78 | unsigned int *datalen, |
| 79 | unsigned int matchoff, |
| 80 | unsigned int matchlen, |
| 81 | u_int16_t port) __read_mostly; |
| 82 | EXPORT_SYMBOL_GPL(nf_nat_sdp_port_hook); |
| 83 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 84 | unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb, |
| 85 | const char **dptr, |
| 86 | unsigned int dataoff, |
| 87 | unsigned int *datalen, |
| 88 | const union nf_inet_addr *addr) |
| 89 | __read_mostly; |
| 90 | EXPORT_SYMBOL_GPL(nf_nat_sdp_session_hook); |
| 91 | |
| 92 | unsigned int (*nf_nat_sdp_media_hook)(struct sk_buff *skb, |
| 93 | const char **dptr, |
| 94 | unsigned int *datalen, |
| 95 | struct nf_conntrack_expect *rtp_exp, |
| 96 | struct nf_conntrack_expect *rtcp_exp, |
| 97 | unsigned int mediaoff, |
| 98 | unsigned int medialen, |
| 99 | union nf_inet_addr *rtp_addr) |
| 100 | __read_mostly; |
| 101 | EXPORT_SYMBOL_GPL(nf_nat_sdp_media_hook); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 102 | |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 103 | static int string_len(const struct nf_conn *ct, const char *dptr, |
| 104 | const char *limit, int *shift) |
| 105 | { |
| 106 | int len = 0; |
| 107 | |
| 108 | while (dptr < limit && isalpha(*dptr)) { |
| 109 | dptr++; |
| 110 | len++; |
| 111 | } |
| 112 | return len; |
| 113 | } |
| 114 | |
Jan Engelhardt | 13f7d63 | 2008-01-31 04:50:25 -0800 | [diff] [blame] | 115 | static int digits_len(const struct nf_conn *ct, const char *dptr, |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 116 | const char *limit, int *shift) |
| 117 | { |
| 118 | int len = 0; |
Patrick McHardy | b1ec488 | 2008-03-25 20:10:11 -0700 | [diff] [blame] | 119 | while (dptr < limit && isdigit(*dptr)) { |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 120 | dptr++; |
| 121 | len++; |
| 122 | } |
| 123 | return len; |
| 124 | } |
| 125 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 126 | /* get media type + port length */ |
| 127 | static int media_len(const struct nf_conn *ct, const char *dptr, |
| 128 | const char *limit, int *shift) |
| 129 | { |
| 130 | int len = string_len(ct, dptr, limit, shift); |
| 131 | |
| 132 | dptr += len; |
| 133 | if (dptr >= limit || *dptr != ' ') |
| 134 | return 0; |
| 135 | len++; |
| 136 | dptr++; |
| 137 | |
| 138 | return len + digits_len(ct, dptr, limit, shift); |
| 139 | } |
| 140 | |
Jan Engelhardt | 13f7d63 | 2008-01-31 04:50:25 -0800 | [diff] [blame] | 141 | static int parse_addr(const struct nf_conn *ct, const char *cp, |
| 142 | const char **endp, union nf_inet_addr *addr, |
| 143 | const char *limit) |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 144 | { |
| 145 | const char *end; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 146 | int ret = 0; |
| 147 | |
Patrick McHardy | fa913dd | 2008-04-14 11:15:45 +0200 | [diff] [blame] | 148 | memset(addr, 0, sizeof(*addr)); |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 149 | switch (nf_ct_l3num(ct)) { |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 150 | case AF_INET: |
| 151 | ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end); |
| 152 | break; |
| 153 | case AF_INET6: |
| 154 | ret = in6_pton(cp, limit - cp, (u8 *)&addr->ip6, -1, &end); |
| 155 | break; |
| 156 | default: |
| 157 | BUG(); |
| 158 | } |
| 159 | |
| 160 | if (ret == 0 || end == cp) |
| 161 | return 0; |
| 162 | if (endp) |
| 163 | *endp = end; |
| 164 | return 1; |
| 165 | } |
| 166 | |
| 167 | /* skip ip address. returns its length. */ |
Jan Engelhardt | 13f7d63 | 2008-01-31 04:50:25 -0800 | [diff] [blame] | 168 | static int epaddr_len(const struct nf_conn *ct, const char *dptr, |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 169 | const char *limit, int *shift) |
| 170 | { |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 171 | union nf_inet_addr addr; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 172 | const char *aux = dptr; |
| 173 | |
| 174 | if (!parse_addr(ct, dptr, &dptr, &addr, limit)) { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 175 | pr_debug("ip: %s parse failed.!\n", dptr); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 176 | return 0; |
| 177 | } |
| 178 | |
| 179 | /* Port number */ |
| 180 | if (*dptr == ':') { |
| 181 | dptr++; |
| 182 | dptr += digits_len(ct, dptr, limit, shift); |
| 183 | } |
| 184 | return dptr - aux; |
| 185 | } |
| 186 | |
| 187 | /* get address length, skiping user info. */ |
Jan Engelhardt | 13f7d63 | 2008-01-31 04:50:25 -0800 | [diff] [blame] | 188 | static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr, |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 189 | const char *limit, int *shift) |
| 190 | { |
Patrick McHardy | aa584ed | 2007-08-14 13:14:35 -0700 | [diff] [blame] | 191 | const char *start = dptr; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 192 | int s = *shift; |
| 193 | |
Lars Immisch | 7da5bfb | 2007-01-30 14:24:57 -0800 | [diff] [blame] | 194 | /* Search for @, but stop at the end of the line. |
| 195 | * We are inside a sip: URI, so we don't need to worry about |
| 196 | * continuation lines. */ |
Patrick McHardy | b1ec488 | 2008-03-25 20:10:11 -0700 | [diff] [blame] | 197 | while (dptr < limit && |
Lars Immisch | 7da5bfb | 2007-01-30 14:24:57 -0800 | [diff] [blame] | 198 | *dptr != '@' && *dptr != '\r' && *dptr != '\n') { |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 199 | (*shift)++; |
Lars Immisch | 7da5bfb | 2007-01-30 14:24:57 -0800 | [diff] [blame] | 200 | dptr++; |
| 201 | } |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 202 | |
Patrick McHardy | b1ec488 | 2008-03-25 20:10:11 -0700 | [diff] [blame] | 203 | if (dptr < limit && *dptr == '@') { |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 204 | dptr++; |
| 205 | (*shift)++; |
Patrick McHardy | aa584ed | 2007-08-14 13:14:35 -0700 | [diff] [blame] | 206 | } else { |
| 207 | dptr = start; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 208 | *shift = s; |
Patrick McHardy | aa584ed | 2007-08-14 13:14:35 -0700 | [diff] [blame] | 209 | } |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 210 | |
| 211 | return epaddr_len(ct, dptr, limit, shift); |
| 212 | } |
| 213 | |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 214 | /* Parse a SIP request line of the form: |
| 215 | * |
| 216 | * Request-Line = Method SP Request-URI SP SIP-Version CRLF |
| 217 | * |
| 218 | * and return the offset and length of the address contained in the Request-URI. |
| 219 | */ |
| 220 | int ct_sip_parse_request(const struct nf_conn *ct, |
| 221 | const char *dptr, unsigned int datalen, |
Patrick McHardy | 624f8b7 | 2008-03-25 20:19:30 -0700 | [diff] [blame] | 222 | unsigned int *matchoff, unsigned int *matchlen, |
| 223 | union nf_inet_addr *addr, __be16 *port) |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 224 | { |
Patrick McHardy | 624f8b7 | 2008-03-25 20:19:30 -0700 | [diff] [blame] | 225 | const char *start = dptr, *limit = dptr + datalen, *end; |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 226 | unsigned int mlen; |
Patrick McHardy | 624f8b7 | 2008-03-25 20:19:30 -0700 | [diff] [blame] | 227 | unsigned int p; |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 228 | int shift = 0; |
| 229 | |
| 230 | /* Skip method and following whitespace */ |
| 231 | mlen = string_len(ct, dptr, limit, NULL); |
| 232 | if (!mlen) |
| 233 | return 0; |
| 234 | dptr += mlen; |
| 235 | if (++dptr >= limit) |
| 236 | return 0; |
| 237 | |
| 238 | /* Find SIP URI */ |
| 239 | limit -= strlen("sip:"); |
| 240 | for (; dptr < limit; dptr++) { |
| 241 | if (*dptr == '\r' || *dptr == '\n') |
| 242 | return -1; |
| 243 | if (strnicmp(dptr, "sip:", strlen("sip:")) == 0) |
| 244 | break; |
| 245 | } |
Patrick McHardy | 624f8b7 | 2008-03-25 20:19:30 -0700 | [diff] [blame] | 246 | if (!skp_epaddr_len(ct, dptr, limit, &shift)) |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 247 | return 0; |
Patrick McHardy | 624f8b7 | 2008-03-25 20:19:30 -0700 | [diff] [blame] | 248 | dptr += shift; |
| 249 | |
| 250 | if (!parse_addr(ct, dptr, &end, addr, limit)) |
| 251 | return -1; |
| 252 | if (end < limit && *end == ':') { |
| 253 | end++; |
| 254 | p = simple_strtoul(end, (char **)&end, 10); |
| 255 | if (p < 1024 || p > 65535) |
| 256 | return -1; |
| 257 | *port = htons(p); |
| 258 | } else |
| 259 | *port = htons(SIP_PORT); |
| 260 | |
| 261 | if (end == dptr) |
| 262 | return 0; |
| 263 | *matchoff = dptr - start; |
| 264 | *matchlen = end - dptr; |
Patrick McHardy | ac36774 | 2008-03-25 20:18:40 -0700 | [diff] [blame] | 265 | return 1; |
| 266 | } |
| 267 | EXPORT_SYMBOL_GPL(ct_sip_parse_request); |
| 268 | |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 269 | /* SIP header parsing: SIP headers are located at the beginning of a line, but |
| 270 | * may span several lines, in which case the continuation lines begin with a |
| 271 | * whitespace character. RFC 2543 allows lines to be terminated with CR, LF or |
| 272 | * CRLF, RFC 3261 allows only CRLF, we support both. |
| 273 | * |
| 274 | * Headers are followed by (optionally) whitespace, a colon, again (optionally) |
| 275 | * whitespace and the values. Whitespace in this context means any amount of |
| 276 | * tabs, spaces and continuation lines, which are treated as a single whitespace |
| 277 | * character. |
Patrick McHardy | 05e3ced | 2008-03-25 20:19:13 -0700 | [diff] [blame] | 278 | * |
| 279 | * Some headers may appear multiple times. A comma seperated list of values is |
| 280 | * equivalent to multiple headers. |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 281 | */ |
| 282 | static const struct sip_header ct_sip_hdrs[] = { |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 283 | [SIP_HDR_CSEQ] = SIP_HDR("CSeq", NULL, NULL, digits_len), |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 284 | [SIP_HDR_FROM] = SIP_HDR("From", "f", "sip:", skp_epaddr_len), |
| 285 | [SIP_HDR_TO] = SIP_HDR("To", "t", "sip:", skp_epaddr_len), |
| 286 | [SIP_HDR_CONTACT] = SIP_HDR("Contact", "m", "sip:", skp_epaddr_len), |
| 287 | [SIP_HDR_VIA] = SIP_HDR("Via", "v", "UDP ", epaddr_len), |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 288 | [SIP_HDR_EXPIRES] = SIP_HDR("Expires", NULL, NULL, digits_len), |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 289 | [SIP_HDR_CONTENT_LENGTH] = SIP_HDR("Content-Length", "l", NULL, digits_len), |
| 290 | }; |
| 291 | |
| 292 | static const char *sip_follow_continuation(const char *dptr, const char *limit) |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 293 | { |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 294 | /* Walk past newline */ |
| 295 | if (++dptr >= limit) |
| 296 | return NULL; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 297 | |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 298 | /* Skip '\n' in CR LF */ |
| 299 | if (*(dptr - 1) == '\r' && *dptr == '\n') { |
| 300 | if (++dptr >= limit) |
| 301 | return NULL; |
| 302 | } |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 303 | |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 304 | /* Continuation line? */ |
| 305 | if (*dptr != ' ' && *dptr != '\t') |
| 306 | return NULL; |
| 307 | |
| 308 | /* skip leading whitespace */ |
| 309 | for (; dptr < limit; dptr++) { |
| 310 | if (*dptr != ' ' && *dptr != '\t') |
| 311 | break; |
| 312 | } |
| 313 | return dptr; |
| 314 | } |
| 315 | |
| 316 | static const char *sip_skip_whitespace(const char *dptr, const char *limit) |
| 317 | { |
| 318 | for (; dptr < limit; dptr++) { |
| 319 | if (*dptr == ' ') |
| 320 | continue; |
| 321 | if (*dptr != '\r' && *dptr != '\n') |
| 322 | break; |
| 323 | dptr = sip_follow_continuation(dptr, limit); |
| 324 | if (dptr == NULL) |
| 325 | return NULL; |
| 326 | } |
| 327 | return dptr; |
| 328 | } |
| 329 | |
| 330 | /* Search within a SIP header value, dealing with continuation lines */ |
| 331 | static const char *ct_sip_header_search(const char *dptr, const char *limit, |
| 332 | const char *needle, unsigned int len) |
| 333 | { |
| 334 | for (limit -= len; dptr < limit; dptr++) { |
| 335 | if (*dptr == '\r' || *dptr == '\n') { |
| 336 | dptr = sip_follow_continuation(dptr, limit); |
| 337 | if (dptr == NULL) |
| 338 | break; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 339 | continue; |
| 340 | } |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 341 | |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 342 | if (strnicmp(dptr, needle, len) == 0) |
| 343 | return dptr; |
| 344 | } |
| 345 | return NULL; |
| 346 | } |
| 347 | |
| 348 | int ct_sip_get_header(const struct nf_conn *ct, const char *dptr, |
| 349 | unsigned int dataoff, unsigned int datalen, |
| 350 | enum sip_header_types type, |
| 351 | unsigned int *matchoff, unsigned int *matchlen) |
| 352 | { |
| 353 | const struct sip_header *hdr = &ct_sip_hdrs[type]; |
| 354 | const char *start = dptr, *limit = dptr + datalen; |
| 355 | int shift = 0; |
| 356 | |
| 357 | for (dptr += dataoff; dptr < limit; dptr++) { |
| 358 | /* Find beginning of line */ |
| 359 | if (*dptr != '\r' && *dptr != '\n') |
| 360 | continue; |
| 361 | if (++dptr >= limit) |
| 362 | break; |
| 363 | if (*(dptr - 1) == '\r' && *dptr == '\n') { |
| 364 | if (++dptr >= limit) |
| 365 | break; |
| 366 | } |
| 367 | |
| 368 | /* Skip continuation lines */ |
| 369 | if (*dptr == ' ' || *dptr == '\t') |
| 370 | continue; |
| 371 | |
| 372 | /* Find header. Compact headers must be followed by a |
| 373 | * non-alphabetic character to avoid mismatches. */ |
| 374 | if (limit - dptr >= hdr->len && |
| 375 | strnicmp(dptr, hdr->name, hdr->len) == 0) |
| 376 | dptr += hdr->len; |
| 377 | else if (hdr->cname && limit - dptr >= hdr->clen + 1 && |
| 378 | strnicmp(dptr, hdr->cname, hdr->clen) == 0 && |
| 379 | !isalpha(*(dptr + hdr->clen + 1))) |
| 380 | dptr += hdr->clen; |
| 381 | else |
| 382 | continue; |
| 383 | |
| 384 | /* Find and skip colon */ |
| 385 | dptr = sip_skip_whitespace(dptr, limit); |
| 386 | if (dptr == NULL) |
| 387 | break; |
| 388 | if (*dptr != ':' || ++dptr >= limit) |
| 389 | break; |
| 390 | |
| 391 | /* Skip whitespace after colon */ |
| 392 | dptr = sip_skip_whitespace(dptr, limit); |
| 393 | if (dptr == NULL) |
| 394 | break; |
| 395 | |
| 396 | *matchoff = dptr - start; |
| 397 | if (hdr->search) { |
| 398 | dptr = ct_sip_header_search(dptr, limit, hdr->search, |
| 399 | hdr->slen); |
| 400 | if (!dptr) |
| 401 | return -1; |
| 402 | dptr += hdr->slen; |
| 403 | } |
| 404 | |
| 405 | *matchlen = hdr->match_len(ct, dptr, limit, &shift); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 406 | if (!*matchlen) |
| 407 | return -1; |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 408 | *matchoff = dptr - start + shift; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 409 | return 1; |
| 410 | } |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 411 | return 0; |
| 412 | } |
Patrick McHardy | ea45f12 | 2008-03-25 20:18:57 -0700 | [diff] [blame] | 413 | EXPORT_SYMBOL_GPL(ct_sip_get_header); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 414 | |
Patrick McHardy | 05e3ced | 2008-03-25 20:19:13 -0700 | [diff] [blame] | 415 | /* Get next header field in a list of comma seperated values */ |
| 416 | static int ct_sip_next_header(const struct nf_conn *ct, const char *dptr, |
| 417 | unsigned int dataoff, unsigned int datalen, |
| 418 | enum sip_header_types type, |
| 419 | unsigned int *matchoff, unsigned int *matchlen) |
| 420 | { |
| 421 | const struct sip_header *hdr = &ct_sip_hdrs[type]; |
| 422 | const char *start = dptr, *limit = dptr + datalen; |
| 423 | int shift = 0; |
| 424 | |
| 425 | dptr += dataoff; |
| 426 | |
| 427 | dptr = ct_sip_header_search(dptr, limit, ",", strlen(",")); |
| 428 | if (!dptr) |
| 429 | return 0; |
| 430 | |
| 431 | dptr = ct_sip_header_search(dptr, limit, hdr->search, hdr->slen); |
| 432 | if (!dptr) |
| 433 | return 0; |
| 434 | dptr += hdr->slen; |
| 435 | |
| 436 | *matchoff = dptr - start; |
| 437 | *matchlen = hdr->match_len(ct, dptr, limit, &shift); |
| 438 | if (!*matchlen) |
| 439 | return -1; |
| 440 | *matchoff += shift; |
| 441 | return 1; |
| 442 | } |
| 443 | |
| 444 | /* Walk through headers until a parsable one is found or no header of the |
| 445 | * given type is left. */ |
| 446 | static int ct_sip_walk_headers(const struct nf_conn *ct, const char *dptr, |
| 447 | unsigned int dataoff, unsigned int datalen, |
| 448 | enum sip_header_types type, int *in_header, |
| 449 | unsigned int *matchoff, unsigned int *matchlen) |
| 450 | { |
| 451 | int ret; |
| 452 | |
| 453 | if (in_header && *in_header) { |
| 454 | while (1) { |
| 455 | ret = ct_sip_next_header(ct, dptr, dataoff, datalen, |
| 456 | type, matchoff, matchlen); |
| 457 | if (ret > 0) |
| 458 | return ret; |
| 459 | if (ret == 0) |
| 460 | break; |
| 461 | dataoff += *matchoff; |
| 462 | } |
| 463 | *in_header = 0; |
| 464 | } |
| 465 | |
| 466 | while (1) { |
| 467 | ret = ct_sip_get_header(ct, dptr, dataoff, datalen, |
| 468 | type, matchoff, matchlen); |
| 469 | if (ret > 0) |
| 470 | break; |
| 471 | if (ret == 0) |
| 472 | return ret; |
| 473 | dataoff += *matchoff; |
| 474 | } |
| 475 | |
| 476 | if (in_header) |
| 477 | *in_header = 1; |
| 478 | return 1; |
| 479 | } |
| 480 | |
| 481 | /* Locate a SIP header, parse the URI and return the offset and length of |
| 482 | * the address as well as the address and port themselves. A stream of |
| 483 | * headers can be parsed by handing in a non-NULL datalen and in_header |
| 484 | * pointer. |
| 485 | */ |
| 486 | int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr, |
| 487 | unsigned int *dataoff, unsigned int datalen, |
| 488 | enum sip_header_types type, int *in_header, |
| 489 | unsigned int *matchoff, unsigned int *matchlen, |
| 490 | union nf_inet_addr *addr, __be16 *port) |
| 491 | { |
| 492 | const char *c, *limit = dptr + datalen; |
| 493 | unsigned int p; |
| 494 | int ret; |
| 495 | |
| 496 | ret = ct_sip_walk_headers(ct, dptr, dataoff ? *dataoff : 0, datalen, |
| 497 | type, in_header, matchoff, matchlen); |
| 498 | WARN_ON(ret < 0); |
| 499 | if (ret == 0) |
| 500 | return ret; |
| 501 | |
| 502 | if (!parse_addr(ct, dptr + *matchoff, &c, addr, limit)) |
| 503 | return -1; |
| 504 | if (*c == ':') { |
| 505 | c++; |
| 506 | p = simple_strtoul(c, (char **)&c, 10); |
| 507 | if (p < 1024 || p > 65535) |
| 508 | return -1; |
| 509 | *port = htons(p); |
| 510 | } else |
| 511 | *port = htons(SIP_PORT); |
| 512 | |
| 513 | if (dataoff) |
| 514 | *dataoff = c - dptr; |
| 515 | return 1; |
| 516 | } |
| 517 | EXPORT_SYMBOL_GPL(ct_sip_parse_header_uri); |
| 518 | |
Patrick McHardy | 2bbb211 | 2008-03-25 20:24:24 -0700 | [diff] [blame] | 519 | /* Parse address from header parameter and return address, offset and length */ |
| 520 | int ct_sip_parse_address_param(const struct nf_conn *ct, const char *dptr, |
| 521 | unsigned int dataoff, unsigned int datalen, |
| 522 | const char *name, |
| 523 | unsigned int *matchoff, unsigned int *matchlen, |
| 524 | union nf_inet_addr *addr) |
| 525 | { |
| 526 | const char *limit = dptr + datalen; |
| 527 | const char *start, *end; |
| 528 | |
| 529 | limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(",")); |
| 530 | if (!limit) |
| 531 | limit = dptr + datalen; |
| 532 | |
| 533 | start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name)); |
| 534 | if (!start) |
| 535 | return 0; |
| 536 | |
| 537 | start += strlen(name); |
| 538 | if (!parse_addr(ct, start, &end, addr, limit)) |
| 539 | return 0; |
| 540 | *matchoff = start - dptr; |
| 541 | *matchlen = end - start; |
| 542 | return 1; |
| 543 | } |
| 544 | EXPORT_SYMBOL_GPL(ct_sip_parse_address_param); |
| 545 | |
| 546 | /* Parse numerical header parameter and return value, offset and length */ |
| 547 | int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr, |
| 548 | unsigned int dataoff, unsigned int datalen, |
| 549 | const char *name, |
| 550 | unsigned int *matchoff, unsigned int *matchlen, |
| 551 | unsigned int *val) |
| 552 | { |
| 553 | const char *limit = dptr + datalen; |
| 554 | const char *start; |
| 555 | char *end; |
| 556 | |
| 557 | limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(",")); |
| 558 | if (!limit) |
| 559 | limit = dptr + datalen; |
| 560 | |
| 561 | start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name)); |
| 562 | if (!start) |
| 563 | return 0; |
| 564 | |
| 565 | start += strlen(name); |
| 566 | *val = simple_strtoul(start, &end, 0); |
| 567 | if (start == end) |
| 568 | return 0; |
| 569 | if (matchoff && matchlen) { |
| 570 | *matchoff = start - dptr; |
| 571 | *matchlen = end - start; |
| 572 | } |
| 573 | return 1; |
| 574 | } |
| 575 | EXPORT_SYMBOL_GPL(ct_sip_parse_numerical_param); |
| 576 | |
Patrick McHardy | 3e9b4600b | 2008-03-25 20:17:55 -0700 | [diff] [blame] | 577 | /* SDP header parsing: a SDP session description contains an ordered set of |
| 578 | * headers, starting with a section containing general session parameters, |
| 579 | * optionally followed by multiple media descriptions. |
| 580 | * |
| 581 | * SDP headers always start at the beginning of a line. According to RFC 2327: |
| 582 | * "The sequence CRLF (0x0d0a) is used to end a record, although parsers should |
| 583 | * be tolerant and also accept records terminated with a single newline |
| 584 | * character". We handle both cases. |
| 585 | */ |
| 586 | static const struct sip_header ct_sdp_hdrs[] = { |
| 587 | [SDP_HDR_VERSION] = SDP_HDR("v=", NULL, digits_len), |
| 588 | [SDP_HDR_OWNER_IP4] = SDP_HDR("o=", "IN IP4 ", epaddr_len), |
| 589 | [SDP_HDR_CONNECTION_IP4] = SDP_HDR("c=", "IN IP4 ", epaddr_len), |
| 590 | [SDP_HDR_OWNER_IP6] = SDP_HDR("o=", "IN IP6 ", epaddr_len), |
| 591 | [SDP_HDR_CONNECTION_IP6] = SDP_HDR("c=", "IN IP6 ", epaddr_len), |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 592 | [SDP_HDR_MEDIA] = SDP_HDR("m=", NULL, media_len), |
Patrick McHardy | 3e9b4600b | 2008-03-25 20:17:55 -0700 | [diff] [blame] | 593 | }; |
| 594 | |
| 595 | /* Linear string search within SDP header values */ |
| 596 | static const char *ct_sdp_header_search(const char *dptr, const char *limit, |
| 597 | const char *needle, unsigned int len) |
| 598 | { |
| 599 | for (limit -= len; dptr < limit; dptr++) { |
| 600 | if (*dptr == '\r' || *dptr == '\n') |
| 601 | break; |
| 602 | if (strncmp(dptr, needle, len) == 0) |
| 603 | return dptr; |
| 604 | } |
| 605 | return NULL; |
| 606 | } |
| 607 | |
| 608 | /* Locate a SDP header (optionally a substring within the header value), |
| 609 | * optionally stopping at the first occurence of the term header, parse |
| 610 | * it and return the offset and length of the data we're interested in. |
| 611 | */ |
| 612 | int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr, |
| 613 | unsigned int dataoff, unsigned int datalen, |
| 614 | enum sdp_header_types type, |
| 615 | enum sdp_header_types term, |
| 616 | unsigned int *matchoff, unsigned int *matchlen) |
| 617 | { |
| 618 | const struct sip_header *hdr = &ct_sdp_hdrs[type]; |
| 619 | const struct sip_header *thdr = &ct_sdp_hdrs[term]; |
| 620 | const char *start = dptr, *limit = dptr + datalen; |
| 621 | int shift = 0; |
| 622 | |
| 623 | for (dptr += dataoff; dptr < limit; dptr++) { |
| 624 | /* Find beginning of line */ |
| 625 | if (*dptr != '\r' && *dptr != '\n') |
| 626 | continue; |
| 627 | if (++dptr >= limit) |
| 628 | break; |
| 629 | if (*(dptr - 1) == '\r' && *dptr == '\n') { |
| 630 | if (++dptr >= limit) |
| 631 | break; |
| 632 | } |
| 633 | |
| 634 | if (term != SDP_HDR_UNSPEC && |
| 635 | limit - dptr >= thdr->len && |
| 636 | strnicmp(dptr, thdr->name, thdr->len) == 0) |
| 637 | break; |
| 638 | else if (limit - dptr >= hdr->len && |
| 639 | strnicmp(dptr, hdr->name, hdr->len) == 0) |
| 640 | dptr += hdr->len; |
| 641 | else |
| 642 | continue; |
| 643 | |
| 644 | *matchoff = dptr - start; |
| 645 | if (hdr->search) { |
| 646 | dptr = ct_sdp_header_search(dptr, limit, hdr->search, |
| 647 | hdr->slen); |
| 648 | if (!dptr) |
| 649 | return -1; |
| 650 | dptr += hdr->slen; |
| 651 | } |
| 652 | |
| 653 | *matchlen = hdr->match_len(ct, dptr, limit, &shift); |
| 654 | if (!*matchlen) |
| 655 | return -1; |
| 656 | *matchoff = dptr - start + shift; |
| 657 | return 1; |
| 658 | } |
| 659 | return 0; |
| 660 | } |
| 661 | EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header); |
| 662 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 663 | static int ct_sip_parse_sdp_addr(const struct nf_conn *ct, const char *dptr, |
| 664 | unsigned int dataoff, unsigned int datalen, |
| 665 | enum sdp_header_types type, |
| 666 | enum sdp_header_types term, |
| 667 | unsigned int *matchoff, unsigned int *matchlen, |
| 668 | union nf_inet_addr *addr) |
| 669 | { |
| 670 | int ret; |
| 671 | |
| 672 | ret = ct_sip_get_sdp_header(ct, dptr, dataoff, datalen, type, term, |
| 673 | matchoff, matchlen); |
| 674 | if (ret <= 0) |
| 675 | return ret; |
| 676 | |
| 677 | if (!parse_addr(ct, dptr + *matchoff, NULL, addr, |
| 678 | dptr + *matchoff + *matchlen)) |
| 679 | return -1; |
| 680 | return 1; |
| 681 | } |
| 682 | |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 683 | static int refresh_signalling_expectation(struct nf_conn *ct, |
| 684 | union nf_inet_addr *addr, |
| 685 | __be16 port, |
| 686 | unsigned int expires) |
| 687 | { |
| 688 | struct nf_conn_help *help = nfct_help(ct); |
| 689 | struct nf_conntrack_expect *exp; |
| 690 | struct hlist_node *n, *next; |
| 691 | int found = 0; |
| 692 | |
| 693 | spin_lock_bh(&nf_conntrack_lock); |
| 694 | hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) { |
| 695 | if (exp->class != SIP_EXPECT_SIGNALLING || |
| 696 | !nf_inet_addr_cmp(&exp->tuple.dst.u3, addr) || |
| 697 | exp->tuple.dst.u.udp.port != port) |
| 698 | continue; |
| 699 | if (!del_timer(&exp->timeout)) |
| 700 | continue; |
| 701 | exp->flags &= ~NF_CT_EXPECT_INACTIVE; |
| 702 | exp->timeout.expires = jiffies + expires * HZ; |
| 703 | add_timer(&exp->timeout); |
| 704 | found = 1; |
| 705 | break; |
| 706 | } |
| 707 | spin_unlock_bh(&nf_conntrack_lock); |
| 708 | return found; |
| 709 | } |
| 710 | |
| 711 | static void flush_expectations(struct nf_conn *ct, bool media) |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 712 | { |
| 713 | struct nf_conn_help *help = nfct_help(ct); |
| 714 | struct nf_conntrack_expect *exp; |
| 715 | struct hlist_node *n, *next; |
| 716 | |
| 717 | spin_lock_bh(&nf_conntrack_lock); |
| 718 | hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) { |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 719 | if ((exp->class != SIP_EXPECT_SIGNALLING) ^ media) |
| 720 | continue; |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 721 | if (!del_timer(&exp->timeout)) |
| 722 | continue; |
| 723 | nf_ct_unlink_expect(exp); |
| 724 | nf_ct_expect_put(exp); |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 725 | if (!media) |
| 726 | break; |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 727 | } |
| 728 | spin_unlock_bh(&nf_conntrack_lock); |
| 729 | } |
| 730 | |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 731 | static int set_expected_rtp_rtcp(struct sk_buff *skb, |
| 732 | const char **dptr, unsigned int *datalen, |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 733 | union nf_inet_addr *daddr, __be16 port, |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 734 | enum sip_expectation_classes class, |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 735 | unsigned int mediaoff, unsigned int medialen) |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 736 | { |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 737 | struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp; |
Patrick McHardy | 212440a | 2008-03-25 20:17:13 -0700 | [diff] [blame] | 738 | enum ip_conntrack_info ctinfo; |
| 739 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
Alexey Dobriyan | a5c3a80 | 2008-10-08 11:35:09 +0200 | [diff] [blame] | 740 | struct net *net = nf_ct_net(ct); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 741 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 742 | union nf_inet_addr *saddr; |
| 743 | struct nf_conntrack_tuple tuple; |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 744 | int direct_rtp = 0, skip_expect = 0, ret = NF_DROP; |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 745 | u_int16_t base_port; |
| 746 | __be16 rtp_port, rtcp_port; |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 747 | typeof(nf_nat_sdp_port_hook) nf_nat_sdp_port; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 748 | typeof(nf_nat_sdp_media_hook) nf_nat_sdp_media; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 749 | |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 750 | saddr = NULL; |
| 751 | if (sip_direct_media) { |
| 752 | if (!nf_inet_addr_cmp(daddr, &ct->tuplehash[dir].tuple.src.u3)) |
| 753 | return NF_ACCEPT; |
| 754 | saddr = &ct->tuplehash[!dir].tuple.src.u3; |
| 755 | } |
| 756 | |
| 757 | /* We need to check whether the registration exists before attempting |
| 758 | * to register it since we can see the same media description multiple |
| 759 | * times on different connections in case multiple endpoints receive |
| 760 | * the same call. |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 761 | * |
| 762 | * RTP optimization: if we find a matching media channel expectation |
| 763 | * and both the expectation and this connection are SNATed, we assume |
| 764 | * both sides can reach each other directly and use the final |
| 765 | * destination address from the expectation. We still need to keep |
| 766 | * the NATed expectations for media that might arrive from the |
| 767 | * outside, and additionally need to expect the direct RTP stream |
| 768 | * in case it passes through us even without NAT. |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 769 | */ |
| 770 | memset(&tuple, 0, sizeof(tuple)); |
| 771 | if (saddr) |
| 772 | tuple.src.u3 = *saddr; |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 773 | tuple.src.l3num = nf_ct_l3num(ct); |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 774 | tuple.dst.protonum = IPPROTO_UDP; |
| 775 | tuple.dst.u3 = *daddr; |
| 776 | tuple.dst.u.udp.port = port; |
| 777 | |
| 778 | rcu_read_lock(); |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 779 | do { |
Alexey Dobriyan | a5c3a80 | 2008-10-08 11:35:09 +0200 | [diff] [blame] | 780 | exp = __nf_ct_expect_find(net, &tuple); |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 781 | |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 782 | if (!exp || exp->master == ct || |
| 783 | nfct_help(exp->master)->helper != nfct_help(ct)->helper || |
| 784 | exp->class != class) |
| 785 | break; |
Patrick McHardy | e1f9a46 | 2008-04-19 17:53:52 -0700 | [diff] [blame] | 786 | #ifdef CONFIG_NF_NAT_NEEDED |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 787 | if (exp->tuple.src.l3num == AF_INET && !direct_rtp && |
| 788 | (exp->saved_ip != exp->tuple.dst.u3.ip || |
| 789 | exp->saved_proto.udp.port != exp->tuple.dst.u.udp.port) && |
| 790 | ct->status & IPS_NAT_MASK) { |
| 791 | daddr->ip = exp->saved_ip; |
| 792 | tuple.dst.u3.ip = exp->saved_ip; |
| 793 | tuple.dst.u.udp.port = exp->saved_proto.udp.port; |
| 794 | direct_rtp = 1; |
| 795 | } else |
Patrick McHardy | e1f9a46 | 2008-04-19 17:53:52 -0700 | [diff] [blame] | 796 | #endif |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 797 | skip_expect = 1; |
| 798 | } while (!skip_expect); |
| 799 | rcu_read_unlock(); |
Patrick McHardy | d901a93 | 2008-03-25 20:25:32 -0700 | [diff] [blame] | 800 | |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 801 | base_port = ntohs(tuple.dst.u.udp.port) & ~1; |
| 802 | rtp_port = htons(base_port); |
| 803 | rtcp_port = htons(base_port + 1); |
| 804 | |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 805 | if (direct_rtp) { |
| 806 | nf_nat_sdp_port = rcu_dereference(nf_nat_sdp_port_hook); |
| 807 | if (nf_nat_sdp_port && |
| 808 | !nf_nat_sdp_port(skb, dptr, datalen, |
| 809 | mediaoff, medialen, ntohs(rtp_port))) |
| 810 | goto err1; |
| 811 | } |
| 812 | |
| 813 | if (skip_expect) |
| 814 | return NF_ACCEPT; |
| 815 | |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 816 | rtp_exp = nf_ct_expect_alloc(ct); |
| 817 | if (rtp_exp == NULL) |
| 818 | goto err1; |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 819 | nf_ct_expect_init(rtp_exp, class, nf_ct_l3num(ct), saddr, daddr, |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 820 | IPPROTO_UDP, NULL, &rtp_port); |
| 821 | |
| 822 | rtcp_exp = nf_ct_expect_alloc(ct); |
| 823 | if (rtcp_exp == NULL) |
| 824 | goto err2; |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 825 | nf_ct_expect_init(rtcp_exp, class, nf_ct_l3num(ct), saddr, daddr, |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 826 | IPPROTO_UDP, NULL, &rtcp_port); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 827 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 828 | nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook); |
Patrick McHardy | c7f485a | 2008-03-25 20:26:43 -0700 | [diff] [blame] | 829 | if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK && !direct_rtp) |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 830 | ret = nf_nat_sdp_media(skb, dptr, datalen, rtp_exp, rtcp_exp, |
| 831 | mediaoff, medialen, daddr); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 832 | else { |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 833 | if (nf_ct_expect_related(rtp_exp) == 0) { |
| 834 | if (nf_ct_expect_related(rtcp_exp) != 0) |
| 835 | nf_ct_unexpect_related(rtp_exp); |
| 836 | else |
| 837 | ret = NF_ACCEPT; |
| 838 | } |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 839 | } |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 840 | nf_ct_expect_put(rtcp_exp); |
| 841 | err2: |
| 842 | nf_ct_expect_put(rtp_exp); |
| 843 | err1: |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 844 | return ret; |
| 845 | } |
| 846 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 847 | static const struct sdp_media_type sdp_media_types[] = { |
| 848 | SDP_MEDIA_TYPE("audio ", SIP_EXPECT_AUDIO), |
| 849 | SDP_MEDIA_TYPE("video ", SIP_EXPECT_VIDEO), |
| 850 | }; |
| 851 | |
| 852 | static const struct sdp_media_type *sdp_media_type(const char *dptr, |
| 853 | unsigned int matchoff, |
| 854 | unsigned int matchlen) |
| 855 | { |
| 856 | const struct sdp_media_type *t; |
| 857 | unsigned int i; |
| 858 | |
| 859 | for (i = 0; i < ARRAY_SIZE(sdp_media_types); i++) { |
| 860 | t = &sdp_media_types[i]; |
| 861 | if (matchlen < t->len || |
| 862 | strncmp(dptr + matchoff, t->name, t->len)) |
| 863 | continue; |
| 864 | return t; |
| 865 | } |
| 866 | return NULL; |
| 867 | } |
| 868 | |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 869 | static int process_sdp(struct sk_buff *skb, |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 870 | const char **dptr, unsigned int *datalen, |
| 871 | unsigned int cseq) |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 872 | { |
| 873 | enum ip_conntrack_info ctinfo; |
| 874 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 875 | struct nf_conn_help *help = nfct_help(ct); |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 876 | unsigned int matchoff, matchlen; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 877 | unsigned int mediaoff, medialen; |
| 878 | unsigned int sdpoff; |
| 879 | unsigned int caddr_len, maddr_len; |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 880 | unsigned int i; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 881 | union nf_inet_addr caddr, maddr, rtp_addr; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 882 | unsigned int port; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 883 | enum sdp_header_types c_hdr; |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 884 | const struct sdp_media_type *t; |
| 885 | int ret = NF_ACCEPT; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 886 | typeof(nf_nat_sdp_addr_hook) nf_nat_sdp_addr; |
| 887 | typeof(nf_nat_sdp_session_hook) nf_nat_sdp_session; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 888 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 889 | nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook); |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 890 | c_hdr = nf_ct_l3num(ct) == AF_INET ? SDP_HDR_CONNECTION_IP4 : |
| 891 | SDP_HDR_CONNECTION_IP6; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 892 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 893 | /* Find beginning of session description */ |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 894 | if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen, |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 895 | SDP_HDR_VERSION, SDP_HDR_UNSPEC, |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 896 | &matchoff, &matchlen) <= 0) |
| 897 | return NF_ACCEPT; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 898 | sdpoff = matchoff; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 899 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 900 | /* The connection information is contained in the session description |
| 901 | * and/or once per media description. The first media description marks |
| 902 | * the end of the session description. */ |
| 903 | caddr_len = 0; |
| 904 | if (ct_sip_parse_sdp_addr(ct, *dptr, sdpoff, *datalen, |
| 905 | c_hdr, SDP_HDR_MEDIA, |
| 906 | &matchoff, &matchlen, &caddr) > 0) |
| 907 | caddr_len = matchlen; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 908 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 909 | mediaoff = sdpoff; |
| 910 | for (i = 0; i < ARRAY_SIZE(sdp_media_types); ) { |
| 911 | if (ct_sip_get_sdp_header(ct, *dptr, mediaoff, *datalen, |
| 912 | SDP_HDR_MEDIA, SDP_HDR_UNSPEC, |
| 913 | &mediaoff, &medialen) <= 0) |
| 914 | break; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 915 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 916 | /* Get media type and port number. A media port value of zero |
| 917 | * indicates an inactive stream. */ |
| 918 | t = sdp_media_type(*dptr, mediaoff, medialen); |
| 919 | if (!t) { |
| 920 | mediaoff += medialen; |
| 921 | continue; |
| 922 | } |
| 923 | mediaoff += t->len; |
| 924 | medialen -= t->len; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 925 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 926 | port = simple_strtoul(*dptr + mediaoff, NULL, 10); |
| 927 | if (port == 0) |
| 928 | continue; |
| 929 | if (port < 1024 || port > 65535) |
| 930 | return NF_DROP; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 931 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 932 | /* The media description overrides the session description. */ |
| 933 | maddr_len = 0; |
| 934 | if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen, |
| 935 | c_hdr, SDP_HDR_MEDIA, |
| 936 | &matchoff, &matchlen, &maddr) > 0) { |
| 937 | maddr_len = matchlen; |
| 938 | memcpy(&rtp_addr, &maddr, sizeof(rtp_addr)); |
| 939 | } else if (caddr_len) |
| 940 | memcpy(&rtp_addr, &caddr, sizeof(rtp_addr)); |
| 941 | else |
| 942 | return NF_DROP; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 943 | |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 944 | ret = set_expected_rtp_rtcp(skb, dptr, datalen, |
| 945 | &rtp_addr, htons(port), t->class, |
| 946 | mediaoff, medialen); |
| 947 | if (ret != NF_ACCEPT) |
| 948 | return ret; |
| 949 | |
| 950 | /* Update media connection address if present */ |
| 951 | if (maddr_len && nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) { |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 952 | ret = nf_nat_sdp_addr(skb, dptr, mediaoff, datalen, |
| 953 | c_hdr, SDP_HDR_MEDIA, &rtp_addr); |
| 954 | if (ret != NF_ACCEPT) |
| 955 | return ret; |
| 956 | } |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 957 | i++; |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 958 | } |
| 959 | |
| 960 | /* Update session connection and owner addresses */ |
| 961 | nf_nat_sdp_session = rcu_dereference(nf_nat_sdp_session_hook); |
| 962 | if (nf_nat_sdp_session && ct->status & IPS_NAT_MASK) |
| 963 | ret = nf_nat_sdp_session(skb, dptr, sdpoff, datalen, &rtp_addr); |
| 964 | |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 965 | if (ret == NF_ACCEPT && i > 0) |
| 966 | help->help.ct_sip_info.invite_cseq = cseq; |
| 967 | |
Patrick McHardy | 4ab9e64 | 2008-03-25 20:26:08 -0700 | [diff] [blame] | 968 | return ret; |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 969 | } |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 970 | static int process_invite_response(struct sk_buff *skb, |
| 971 | const char **dptr, unsigned int *datalen, |
| 972 | unsigned int cseq, unsigned int code) |
| 973 | { |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 974 | enum ip_conntrack_info ctinfo; |
| 975 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 976 | struct nf_conn_help *help = nfct_help(ct); |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 977 | |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 978 | if ((code >= 100 && code <= 199) || |
| 979 | (code >= 200 && code <= 299)) |
| 980 | return process_sdp(skb, dptr, datalen, cseq); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 981 | else if (help->help.ct_sip_info.invite_cseq == cseq) |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 982 | flush_expectations(ct, true); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 983 | return NF_ACCEPT; |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 984 | } |
| 985 | |
| 986 | static int process_update_response(struct sk_buff *skb, |
| 987 | const char **dptr, unsigned int *datalen, |
| 988 | unsigned int cseq, unsigned int code) |
| 989 | { |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 990 | enum ip_conntrack_info ctinfo; |
| 991 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 992 | struct nf_conn_help *help = nfct_help(ct); |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 993 | |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 994 | if ((code >= 100 && code <= 199) || |
| 995 | (code >= 200 && code <= 299)) |
| 996 | return process_sdp(skb, dptr, datalen, cseq); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 997 | else if (help->help.ct_sip_info.invite_cseq == cseq) |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 998 | flush_expectations(ct, true); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 999 | return NF_ACCEPT; |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1000 | } |
| 1001 | |
Patrick McHardy | 595a8ec | 2008-03-25 20:22:53 -0700 | [diff] [blame] | 1002 | static int process_prack_response(struct sk_buff *skb, |
| 1003 | const char **dptr, unsigned int *datalen, |
| 1004 | unsigned int cseq, unsigned int code) |
| 1005 | { |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 1006 | enum ip_conntrack_info ctinfo; |
| 1007 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 1008 | struct nf_conn_help *help = nfct_help(ct); |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 1009 | |
Patrick McHardy | 595a8ec | 2008-03-25 20:22:53 -0700 | [diff] [blame] | 1010 | if ((code >= 100 && code <= 199) || |
| 1011 | (code >= 200 && code <= 299)) |
| 1012 | return process_sdp(skb, dptr, datalen, cseq); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 1013 | else if (help->help.ct_sip_info.invite_cseq == cseq) |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1014 | flush_expectations(ct, true); |
Patrick McHardy | ef75d49 | 2008-05-08 01:15:21 -0700 | [diff] [blame] | 1015 | return NF_ACCEPT; |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 1016 | } |
Patrick McHardy | 595a8ec | 2008-03-25 20:22:53 -0700 | [diff] [blame] | 1017 | |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 1018 | static int process_bye_request(struct sk_buff *skb, |
| 1019 | const char **dptr, unsigned int *datalen, |
| 1020 | unsigned int cseq) |
| 1021 | { |
| 1022 | enum ip_conntrack_info ctinfo; |
| 1023 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 1024 | |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1025 | flush_expectations(ct, true); |
| 1026 | return NF_ACCEPT; |
| 1027 | } |
| 1028 | |
| 1029 | /* Parse a REGISTER request and create a permanent expectation for incoming |
| 1030 | * signalling connections. The expectation is marked inactive and is activated |
| 1031 | * when receiving a response indicating success from the registrar. |
| 1032 | */ |
| 1033 | static int process_register_request(struct sk_buff *skb, |
| 1034 | const char **dptr, unsigned int *datalen, |
| 1035 | unsigned int cseq) |
| 1036 | { |
| 1037 | enum ip_conntrack_info ctinfo; |
| 1038 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 1039 | struct nf_conn_help *help = nfct_help(ct); |
| 1040 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1041 | unsigned int matchoff, matchlen; |
| 1042 | struct nf_conntrack_expect *exp; |
| 1043 | union nf_inet_addr *saddr, daddr; |
| 1044 | __be16 port; |
| 1045 | unsigned int expires = 0; |
| 1046 | int ret; |
| 1047 | typeof(nf_nat_sip_expect_hook) nf_nat_sip_expect; |
| 1048 | |
| 1049 | /* Expected connections can not register again. */ |
| 1050 | if (ct->status & IPS_EXPECTED) |
| 1051 | return NF_ACCEPT; |
| 1052 | |
| 1053 | /* We must check the expiration time: a value of zero signals the |
| 1054 | * registrar to release the binding. We'll remove our expectation |
| 1055 | * when receiving the new bindings in the response, but we don't |
| 1056 | * want to create new ones. |
| 1057 | * |
| 1058 | * The expiration time may be contained in Expires: header, the |
| 1059 | * Contact: header parameters or the URI parameters. |
| 1060 | */ |
| 1061 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES, |
| 1062 | &matchoff, &matchlen) > 0) |
| 1063 | expires = simple_strtoul(*dptr + matchoff, NULL, 10); |
| 1064 | |
| 1065 | ret = ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, |
| 1066 | SIP_HDR_CONTACT, NULL, |
| 1067 | &matchoff, &matchlen, &daddr, &port); |
| 1068 | if (ret < 0) |
| 1069 | return NF_DROP; |
| 1070 | else if (ret == 0) |
| 1071 | return NF_ACCEPT; |
| 1072 | |
| 1073 | /* We don't support third-party registrations */ |
| 1074 | if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, &daddr)) |
| 1075 | return NF_ACCEPT; |
| 1076 | |
| 1077 | if (ct_sip_parse_numerical_param(ct, *dptr, |
| 1078 | matchoff + matchlen, *datalen, |
| 1079 | "expires=", NULL, NULL, &expires) < 0) |
| 1080 | return NF_DROP; |
| 1081 | |
| 1082 | if (expires == 0) { |
| 1083 | ret = NF_ACCEPT; |
| 1084 | goto store_cseq; |
| 1085 | } |
| 1086 | |
| 1087 | exp = nf_ct_expect_alloc(ct); |
| 1088 | if (!exp) |
| 1089 | return NF_DROP; |
| 1090 | |
| 1091 | saddr = NULL; |
| 1092 | if (sip_direct_signalling) |
| 1093 | saddr = &ct->tuplehash[!dir].tuple.src.u3; |
| 1094 | |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 1095 | nf_ct_expect_init(exp, SIP_EXPECT_SIGNALLING, nf_ct_l3num(ct), |
| 1096 | saddr, &daddr, IPPROTO_UDP, NULL, &port); |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1097 | exp->timeout.expires = sip_timeout * HZ; |
| 1098 | exp->helper = nfct_help(ct)->helper; |
| 1099 | exp->flags = NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE; |
| 1100 | |
| 1101 | nf_nat_sip_expect = rcu_dereference(nf_nat_sip_expect_hook); |
| 1102 | if (nf_nat_sip_expect && ct->status & IPS_NAT_MASK) |
| 1103 | ret = nf_nat_sip_expect(skb, dptr, datalen, exp, |
| 1104 | matchoff, matchlen); |
| 1105 | else { |
| 1106 | if (nf_ct_expect_related(exp) != 0) |
| 1107 | ret = NF_DROP; |
| 1108 | else |
| 1109 | ret = NF_ACCEPT; |
| 1110 | } |
| 1111 | nf_ct_expect_put(exp); |
| 1112 | |
| 1113 | store_cseq: |
| 1114 | if (ret == NF_ACCEPT) |
| 1115 | help->help.ct_sip_info.register_cseq = cseq; |
| 1116 | return ret; |
| 1117 | } |
| 1118 | |
| 1119 | static int process_register_response(struct sk_buff *skb, |
| 1120 | const char **dptr, unsigned int *datalen, |
| 1121 | unsigned int cseq, unsigned int code) |
| 1122 | { |
| 1123 | enum ip_conntrack_info ctinfo; |
| 1124 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 1125 | struct nf_conn_help *help = nfct_help(ct); |
| 1126 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 1127 | union nf_inet_addr addr; |
| 1128 | __be16 port; |
| 1129 | unsigned int matchoff, matchlen, dataoff = 0; |
| 1130 | unsigned int expires = 0; |
| 1131 | int in_contact = 0, ret; |
| 1132 | |
| 1133 | /* According to RFC 3261, "UAs MUST NOT send a new registration until |
| 1134 | * they have received a final response from the registrar for the |
| 1135 | * previous one or the previous REGISTER request has timed out". |
| 1136 | * |
| 1137 | * However, some servers fail to detect retransmissions and send late |
| 1138 | * responses, so we store the sequence number of the last valid |
| 1139 | * request and compare it here. |
| 1140 | */ |
| 1141 | if (help->help.ct_sip_info.register_cseq != cseq) |
| 1142 | return NF_ACCEPT; |
| 1143 | |
| 1144 | if (code >= 100 && code <= 199) |
| 1145 | return NF_ACCEPT; |
| 1146 | if (code < 200 || code > 299) |
| 1147 | goto flush; |
| 1148 | |
| 1149 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES, |
| 1150 | &matchoff, &matchlen) > 0) |
| 1151 | expires = simple_strtoul(*dptr + matchoff, NULL, 10); |
| 1152 | |
| 1153 | while (1) { |
| 1154 | unsigned int c_expires = expires; |
| 1155 | |
| 1156 | ret = ct_sip_parse_header_uri(ct, *dptr, &dataoff, *datalen, |
| 1157 | SIP_HDR_CONTACT, &in_contact, |
| 1158 | &matchoff, &matchlen, |
| 1159 | &addr, &port); |
| 1160 | if (ret < 0) |
| 1161 | return NF_DROP; |
| 1162 | else if (ret == 0) |
| 1163 | break; |
| 1164 | |
| 1165 | /* We don't support third-party registrations */ |
| 1166 | if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, &addr)) |
| 1167 | continue; |
| 1168 | |
| 1169 | ret = ct_sip_parse_numerical_param(ct, *dptr, |
| 1170 | matchoff + matchlen, |
| 1171 | *datalen, "expires=", |
| 1172 | NULL, NULL, &c_expires); |
| 1173 | if (ret < 0) |
| 1174 | return NF_DROP; |
| 1175 | if (c_expires == 0) |
| 1176 | break; |
| 1177 | if (refresh_signalling_expectation(ct, &addr, port, c_expires)) |
| 1178 | return NF_ACCEPT; |
| 1179 | } |
| 1180 | |
| 1181 | flush: |
| 1182 | flush_expectations(ct, false); |
Patrick McHardy | 595a8ec | 2008-03-25 20:22:53 -0700 | [diff] [blame] | 1183 | return NF_ACCEPT; |
| 1184 | } |
| 1185 | |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1186 | static const struct sip_handler sip_handlers[] = { |
| 1187 | SIP_HANDLER("INVITE", process_sdp, process_invite_response), |
| 1188 | SIP_HANDLER("UPDATE", process_sdp, process_update_response), |
Patrick McHardy | 595a8ec | 2008-03-25 20:22:53 -0700 | [diff] [blame] | 1189 | SIP_HANDLER("ACK", process_sdp, NULL), |
| 1190 | SIP_HANDLER("PRACK", process_sdp, process_prack_response), |
Patrick McHardy | 9467ee3 | 2008-03-25 20:24:04 -0700 | [diff] [blame] | 1191 | SIP_HANDLER("BYE", process_bye_request, NULL), |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1192 | SIP_HANDLER("REGISTER", process_register_request, process_register_response), |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1193 | }; |
| 1194 | |
| 1195 | static int process_sip_response(struct sk_buff *skb, |
| 1196 | const char **dptr, unsigned int *datalen) |
| 1197 | { |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1198 | enum ip_conntrack_info ctinfo; |
| 1199 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 1200 | unsigned int matchoff, matchlen; |
| 1201 | unsigned int code, cseq, dataoff, i; |
| 1202 | |
| 1203 | if (*datalen < strlen("SIP/2.0 200")) |
| 1204 | return NF_ACCEPT; |
| 1205 | code = simple_strtoul(*dptr + strlen("SIP/2.0 "), NULL, 10); |
| 1206 | if (!code) |
| 1207 | return NF_DROP; |
| 1208 | |
| 1209 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ, |
| 1210 | &matchoff, &matchlen) <= 0) |
| 1211 | return NF_DROP; |
| 1212 | cseq = simple_strtoul(*dptr + matchoff, NULL, 10); |
| 1213 | if (!cseq) |
| 1214 | return NF_DROP; |
| 1215 | dataoff = matchoff + matchlen + 1; |
| 1216 | |
| 1217 | for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) { |
Alexey Dobriyan | 66bf791 | 2008-09-07 18:19:25 -0700 | [diff] [blame] | 1218 | const struct sip_handler *handler; |
| 1219 | |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1220 | handler = &sip_handlers[i]; |
| 1221 | if (handler->response == NULL) |
| 1222 | continue; |
| 1223 | if (*datalen < dataoff + handler->len || |
| 1224 | strnicmp(*dptr + dataoff, handler->method, handler->len)) |
| 1225 | continue; |
| 1226 | return handler->response(skb, dptr, datalen, cseq, code); |
| 1227 | } |
| 1228 | return NF_ACCEPT; |
| 1229 | } |
| 1230 | |
| 1231 | static int process_sip_request(struct sk_buff *skb, |
| 1232 | const char **dptr, unsigned int *datalen) |
| 1233 | { |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1234 | enum ip_conntrack_info ctinfo; |
| 1235 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 1236 | unsigned int matchoff, matchlen; |
| 1237 | unsigned int cseq, i; |
| 1238 | |
| 1239 | for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) { |
Alexey Dobriyan | 66bf791 | 2008-09-07 18:19:25 -0700 | [diff] [blame] | 1240 | const struct sip_handler *handler; |
| 1241 | |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1242 | handler = &sip_handlers[i]; |
| 1243 | if (handler->request == NULL) |
| 1244 | continue; |
| 1245 | if (*datalen < handler->len || |
| 1246 | strnicmp(*dptr, handler->method, handler->len)) |
| 1247 | continue; |
| 1248 | |
| 1249 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ, |
| 1250 | &matchoff, &matchlen) <= 0) |
| 1251 | return NF_DROP; |
| 1252 | cseq = simple_strtoul(*dptr + matchoff, NULL, 10); |
| 1253 | if (!cseq) |
| 1254 | return NF_DROP; |
| 1255 | |
| 1256 | return handler->request(skb, dptr, datalen, cseq); |
| 1257 | } |
| 1258 | return NF_ACCEPT; |
| 1259 | } |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 1260 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 1261 | static int sip_help(struct sk_buff *skb, |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1262 | unsigned int protoff, |
| 1263 | struct nf_conn *ct, |
| 1264 | enum ip_conntrack_info ctinfo) |
| 1265 | { |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1266 | unsigned int dataoff, datalen; |
| 1267 | const char *dptr; |
Patrick McHardy | 33cb1e9 | 2008-03-25 20:22:37 -0700 | [diff] [blame] | 1268 | int ret; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1269 | typeof(nf_nat_sip_hook) nf_nat_sip; |
| 1270 | |
| 1271 | /* No Data ? */ |
| 1272 | dataoff = protoff + sizeof(struct udphdr); |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 1273 | if (dataoff >= skb->len) |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1274 | return NF_ACCEPT; |
| 1275 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 1276 | nf_ct_refresh(ct, skb, sip_timeout * HZ); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1277 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 1278 | if (!skb_is_nonlinear(skb)) |
| 1279 | dptr = skb->data + dataoff; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1280 | else { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 1281 | pr_debug("Copy of skbuff not supported yet.\n"); |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 1282 | return NF_ACCEPT; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1283 | } |
| 1284 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 1285 | datalen = skb->len - dataoff; |
Patrick McHardy | 779382e | 2008-03-25 20:17:36 -0700 | [diff] [blame] | 1286 | if (datalen < strlen("SIP/2.0 200")) |
Patrick McHardy | 7d3dd04 | 2008-03-25 20:19:46 -0700 | [diff] [blame] | 1287 | return NF_ACCEPT; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1288 | |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1289 | if (strnicmp(dptr, "SIP/2.0 ", strlen("SIP/2.0 ")) != 0) |
Patrick McHardy | 33cb1e9 | 2008-03-25 20:22:37 -0700 | [diff] [blame] | 1290 | ret = process_sip_request(skb, &dptr, &datalen); |
Patrick McHardy | 30f33e6 | 2008-03-25 20:22:20 -0700 | [diff] [blame] | 1291 | else |
Patrick McHardy | 33cb1e9 | 2008-03-25 20:22:37 -0700 | [diff] [blame] | 1292 | ret = process_sip_response(skb, &dptr, &datalen); |
| 1293 | |
| 1294 | if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) { |
| 1295 | nf_nat_sip = rcu_dereference(nf_nat_sip_hook); |
| 1296 | if (nf_nat_sip && !nf_nat_sip(skb, &dptr, &datalen)) |
| 1297 | ret = NF_DROP; |
| 1298 | } |
| 1299 | |
| 1300 | return ret; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1301 | } |
| 1302 | |
| 1303 | static struct nf_conntrack_helper sip[MAX_PORTS][2] __read_mostly; |
| 1304 | static char sip_names[MAX_PORTS][2][sizeof("sip-65535")] __read_mostly; |
| 1305 | |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1306 | static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1] = { |
| 1307 | [SIP_EXPECT_SIGNALLING] = { |
| 1308 | .max_expected = 1, |
| 1309 | .timeout = 3 * 60, |
| 1310 | }, |
| 1311 | [SIP_EXPECT_AUDIO] = { |
Patrick McHardy | a9c1d35 | 2008-03-25 20:25:49 -0700 | [diff] [blame] | 1312 | .max_expected = 2 * IP_CT_DIR_MAX, |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1313 | .timeout = 3 * 60, |
| 1314 | }, |
Patrick McHardy | 0d0ab03 | 2008-03-25 20:26:24 -0700 | [diff] [blame] | 1315 | [SIP_EXPECT_VIDEO] = { |
| 1316 | .max_expected = 2 * IP_CT_DIR_MAX, |
| 1317 | .timeout = 3 * 60, |
| 1318 | }, |
Patrick McHardy | 6002f266 | 2008-03-25 20:09:15 -0700 | [diff] [blame] | 1319 | }; |
| 1320 | |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1321 | static void nf_conntrack_sip_fini(void) |
| 1322 | { |
| 1323 | int i, j; |
| 1324 | |
| 1325 | for (i = 0; i < ports_c; i++) { |
| 1326 | for (j = 0; j < 2; j++) { |
| 1327 | if (sip[i][j].me == NULL) |
| 1328 | continue; |
| 1329 | nf_conntrack_helper_unregister(&sip[i][j]); |
| 1330 | } |
| 1331 | } |
| 1332 | } |
| 1333 | |
| 1334 | static int __init nf_conntrack_sip_init(void) |
| 1335 | { |
| 1336 | int i, j, ret; |
| 1337 | char *tmpname; |
| 1338 | |
| 1339 | if (ports_c == 0) |
| 1340 | ports[ports_c++] = SIP_PORT; |
| 1341 | |
| 1342 | for (i = 0; i < ports_c; i++) { |
| 1343 | memset(&sip[i], 0, sizeof(sip[i])); |
| 1344 | |
| 1345 | sip[i][0].tuple.src.l3num = AF_INET; |
| 1346 | sip[i][1].tuple.src.l3num = AF_INET6; |
| 1347 | for (j = 0; j < 2; j++) { |
| 1348 | sip[i][j].tuple.dst.protonum = IPPROTO_UDP; |
| 1349 | sip[i][j].tuple.src.u.udp.port = htons(ports[i]); |
Patrick McHardy | 0f32a40 | 2008-03-25 20:25:13 -0700 | [diff] [blame] | 1350 | sip[i][j].expect_policy = sip_exp_policy; |
| 1351 | sip[i][j].expect_class_max = SIP_EXPECT_MAX; |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1352 | sip[i][j].me = THIS_MODULE; |
| 1353 | sip[i][j].help = sip_help; |
| 1354 | |
| 1355 | tmpname = &sip_names[i][j][0]; |
| 1356 | if (ports[i] == SIP_PORT) |
| 1357 | sprintf(tmpname, "sip"); |
| 1358 | else |
| 1359 | sprintf(tmpname, "sip-%u", i); |
| 1360 | sip[i][j].name = tmpname; |
| 1361 | |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 1362 | pr_debug("port #%u: %u\n", i, ports[i]); |
Patrick McHardy | 9fafcd7 | 2006-12-02 22:09:57 -0800 | [diff] [blame] | 1363 | |
| 1364 | ret = nf_conntrack_helper_register(&sip[i][j]); |
| 1365 | if (ret) { |
| 1366 | printk("nf_ct_sip: failed to register helper " |
| 1367 | "for pf: %u port: %u\n", |
| 1368 | sip[i][j].tuple.src.l3num, ports[i]); |
| 1369 | nf_conntrack_sip_fini(); |
| 1370 | return ret; |
| 1371 | } |
| 1372 | } |
| 1373 | } |
| 1374 | return 0; |
| 1375 | } |
| 1376 | |
| 1377 | module_init(nf_conntrack_sip_init); |
| 1378 | module_exit(nf_conntrack_sip_fini); |