ip_raudio_pxy.c revision 369245
1/* $FreeBSD: stable/11/sys/contrib/ipfilter/netinet/ip_raudio_pxy.c 369245 2021-02-09 13:47:46Z git2svn $ */ 2 3/* 4 * Copyright (C) 2012 by Darren Reed. 5 * 6 * See the IPFILTER.LICENCE file for details on licencing. 7 * 8 * $Id: ip_raudio_pxy.c,v 1.40.2.4 2006/07/14 06:12:17 darrenr Exp $ 9 */ 10 11#define IPF_RAUDIO_PROXY 12 13 14void ipf_p_raudio_main_load(void); 15void ipf_p_raudio_main_unload(void); 16int ipf_p_raudio_new(void *, fr_info_t *, ap_session_t *, nat_t *); 17int ipf_p_raudio_in(void *, fr_info_t *, ap_session_t *, nat_t *); 18int ipf_p_raudio_out(void *, fr_info_t *, ap_session_t *, nat_t *); 19 20static frentry_t raudiofr; 21 22int raudio_proxy_init = 0; 23 24 25/* 26 * Real Audio application proxy initialization. 27 */ 28void 29ipf_p_raudio_main_load() 30{ 31 bzero((char *)&raudiofr, sizeof(raudiofr)); 32 raudiofr.fr_ref = 1; 33 raudiofr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE; 34 MUTEX_INIT(&raudiofr.fr_lock, "Real Audio proxy rule lock"); 35 raudio_proxy_init = 1; 36} 37 38 39void 40ipf_p_raudio_main_unload() 41{ 42 if (raudio_proxy_init == 1) { 43 MUTEX_DESTROY(&raudiofr.fr_lock); 44 raudio_proxy_init = 0; 45 } 46} 47 48 49/* 50 * Setup for a new proxy to handle Real Audio. 51 */ 52int 53ipf_p_raudio_new(arg, fin, aps, nat) 54 void *arg; 55 fr_info_t *fin; 56 ap_session_t *aps; 57 nat_t *nat; 58{ 59 raudio_t *rap; 60 61 nat = nat; /* LINT */ 62 63 if (fin->fin_v != 4) 64 return -1; 65 66 KMALLOCS(aps->aps_data, void *, sizeof(raudio_t)); 67 if (aps->aps_data == NULL) 68 return -1; 69 70 bzero(aps->aps_data, sizeof(raudio_t)); 71 rap = aps->aps_data; 72 aps->aps_psiz = sizeof(raudio_t); 73 rap->rap_mode = RAP_M_TCP; /* default is for TCP */ 74 return 0; 75} 76 77 78 79int 80ipf_p_raudio_out(arg, fin, aps, nat) 81 void *arg; 82 fr_info_t *fin; 83 ap_session_t *aps; 84 nat_t *nat; 85{ 86 raudio_t *rap = aps->aps_data; 87 unsigned char membuf[512 + 1], *s; 88 u_short id = 0; 89 tcphdr_t *tcp; 90 int off, dlen; 91 int len = 0; 92 mb_t *m; 93 94 nat = nat; /* LINT */ 95 96 /* 97 * If we've already processed the start messages, then nothing left 98 * for the proxy to do. 99 */ 100 if (rap->rap_eos == 1) 101 return 0; 102 103 m = fin->fin_m; 104 tcp = (tcphdr_t *)fin->fin_dp; 105 off = (char *)tcp - (char *)fin->fin_ip; 106 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff; 107 108 dlen = MSGDSIZE(m) - off; 109 if (dlen <= 0) 110 return 0; 111 112 if (dlen > sizeof(membuf)) 113 dlen = sizeof(membuf); 114 115 bzero((char *)membuf, sizeof(membuf)); 116 COPYDATA(m, off, dlen, (char *)membuf); 117 /* 118 * In all the startup parsing, ensure that we don't go outside 119 * the packet buffer boundary. 120 */ 121 /* 122 * Look for the start of connection "PNA" string if not seen yet. 123 */ 124 if (rap->rap_seenpna == 0) { 125 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen); 126 if (s == NULL) 127 return 0; 128 s += 3; 129 rap->rap_seenpna = 1; 130 } else 131 s = membuf; 132 133 /* 134 * Directly after the PNA will be the version number of this 135 * connection. 136 */ 137 if (rap->rap_seenpna == 1 && rap->rap_seenver == 0) { 138 if ((s + 1) - membuf < dlen) { 139 rap->rap_version = (*s << 8) | *(s + 1); 140 s += 2; 141 rap->rap_seenver = 1; 142 } else 143 return 0; 144 } 145 146 /* 147 * Now that we've been past the PNA and version number, we're into the 148 * startup messages block. This ends when a message with an ID of 0. 149 */ 150 while ((rap->rap_eos == 0) && ((s + 1) - membuf < dlen)) { 151 if (rap->rap_gotid == 0) { 152 id = (*s << 8) | *(s + 1); 153 s += 2; 154 rap->rap_gotid = 1; 155 if (id == RA_ID_END) { 156 rap->rap_eos = 1; 157 break; 158 } 159 } else if (rap->rap_gotlen == 0) { 160 len = (*s << 8) | *(s + 1); 161 s += 2; 162 rap->rap_gotlen = 1; 163 } 164 165 if (rap->rap_gotid == 1 && rap->rap_gotlen == 1) { 166 if (id == RA_ID_UDP) { 167 rap->rap_mode &= ~RAP_M_TCP; 168 rap->rap_mode |= RAP_M_UDP; 169 rap->rap_plport = (*s << 8) | *(s + 1); 170 } else if (id == RA_ID_ROBUST) { 171 rap->rap_mode |= RAP_M_ROBUST; 172 rap->rap_prport = (*s << 8) | *(s + 1); 173 } 174 s += len; 175 rap->rap_gotlen = 0; 176 rap->rap_gotid = 0; 177 } 178 } 179 return 0; 180} 181 182 183int 184ipf_p_raudio_in(arg, fin, aps, nat) 185 void *arg; 186 fr_info_t *fin; 187 ap_session_t *aps; 188 nat_t *nat; 189{ 190 unsigned char membuf[IPF_MAXPORTLEN + 1], *s; 191 tcphdr_t *tcp, tcph, *tcp2 = &tcph; 192 raudio_t *rap = aps->aps_data; 193 ipf_main_softc_t *softc; 194 ipf_nat_softc_t *softn; 195 struct in_addr swa, swb; 196 int off, dlen, slen; 197 int a1, a2, a3, a4; 198 u_short sp, dp; 199 fr_info_t fi; 200 tcp_seq seq; 201 nat_t *nat2; 202 u_char swp; 203 ip_t *ip; 204 mb_t *m; 205 206 softc = fin->fin_main_soft; 207 softn = softc->ipf_nat_soft; 208 /* 209 * Wait until we've seen the end of the start messages and even then 210 * only proceed further if we're using UDP. If they want to use TCP 211 * then data is sent back on the same channel that is already open. 212 */ 213 if (rap->rap_sdone != 0) 214 return 0; 215 216 m = fin->fin_m; 217 tcp = (tcphdr_t *)fin->fin_dp; 218 off = (char *)tcp - (char *)fin->fin_ip; 219 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff; 220 221 dlen = MSGDSIZE(m) - off; 222 if (dlen <= 0) 223 return 0; 224 225 if (dlen > sizeof(membuf)) 226 dlen = sizeof(membuf); 227 228 bzero((char *)membuf, sizeof(membuf)); 229 COPYDATA(m, off, dlen, (char *)membuf); 230 231 seq = ntohl(tcp->th_seq); 232 /* 233 * Check to see if the data in this packet is of interest to us. 234 * We only care for the first 19 bytes coming back from the server. 235 */ 236 if (rap->rap_sseq == 0) { 237 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen); 238 if (s == NULL) 239 return 0; 240 a1 = s - membuf; 241 dlen -= a1; 242 a1 = 0; 243 rap->rap_sseq = seq; 244 a2 = MIN(dlen, sizeof(rap->rap_svr)); 245 } else if (seq <= rap->rap_sseq + sizeof(rap->rap_svr)) { 246 /* 247 * seq # which is the start of data and from that the offset 248 * into the buffer array. 249 */ 250 a1 = seq - rap->rap_sseq; 251 a2 = MIN(dlen, sizeof(rap->rap_svr)); 252 a2 -= a1; 253 s = membuf; 254 } else 255 return 0; 256 257 for (a3 = a1, a4 = a2; (a4 > 0) && (a3 < 19) && (a3 >= 0); a4--,a3++) { 258 rap->rap_sbf |= (1 << a3); 259 rap->rap_svr[a3] = *s++; 260 } 261 262 if ((rap->rap_sbf != 0x7ffff) || (!rap->rap_eos)) /* 19 bits */ 263 return 0; 264 rap->rap_sdone = 1; 265 266 s = (u_char *)rap->rap_svr + 11; 267 if (((*s << 8) | *(s + 1)) == RA_ID_ROBUST) { 268 s += 2; 269 rap->rap_srport = (*s << 8) | *(s + 1); 270 } 271 272 ip = fin->fin_ip; 273 swp = ip->ip_p; 274 swa = ip->ip_src; 275 swb = ip->ip_dst; 276 277 ip->ip_p = IPPROTO_UDP; 278 ip->ip_src = nat->nat_ndstip; 279 ip->ip_dst = nat->nat_odstip; 280 281 bcopy((char *)fin, (char *)&fi, sizeof(fi)); 282 bzero((char *)tcp2, sizeof(*tcp2)); 283 TCP_OFF_A(tcp2, 5); 284 fi.fin_flx |= FI_IGNORE; 285 fi.fin_dp = (char *)tcp2; 286 fi.fin_fr = &raudiofr; 287 fi.fin_dlen = sizeof(*tcp2); 288 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2); 289 tcp2->th_win = htons(8192); 290 slen = ip->ip_len; 291 ip->ip_len = htons(fin->fin_hlen + sizeof(*tcp)); 292 293 if (((rap->rap_mode & RAP_M_UDP_ROBUST) == RAP_M_UDP_ROBUST) && 294 (rap->rap_srport != 0)) { 295 dp = rap->rap_srport; 296 sp = rap->rap_prport; 297 tcp2->th_sport = htons(sp); 298 tcp2->th_dport = htons(dp); 299 fi.fin_data[0] = dp; 300 fi.fin_data[1] = sp; 301 fi.fin_out = 0; 302 MUTEX_ENTER(&softn->ipf_nat_new); 303 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL, 304 NAT_SLAVE|IPN_UDP | (sp ? 0 : SI_W_SPORT), 305 NAT_OUTBOUND); 306 MUTEX_EXIT(&softn->ipf_nat_new); 307 if (nat2 != NULL) { 308 (void) ipf_nat_proto(&fi, nat2, IPN_UDP); 309 MUTEX_ENTER(&nat2->nat_lock); 310 ipf_nat_update(&fi, nat2); 311 MUTEX_EXIT(&nat2->nat_lock); 312 313 (void) ipf_state_add(softc, &fi, NULL, 314 (sp ? 0 : SI_W_SPORT)); 315 } 316 } 317 318 if ((rap->rap_mode & RAP_M_UDP) == RAP_M_UDP) { 319 sp = rap->rap_plport; 320 tcp2->th_sport = htons(sp); 321 tcp2->th_dport = 0; /* XXX - don't specify remote port */ 322 fi.fin_data[0] = sp; 323 fi.fin_data[1] = 0; 324 fi.fin_out = 1; 325 MUTEX_ENTER(&softn->ipf_nat_new); 326 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL, 327 NAT_SLAVE|IPN_UDP|SI_W_DPORT, 328 NAT_OUTBOUND); 329 MUTEX_EXIT(&softn->ipf_nat_new); 330 if (nat2 != NULL) { 331 (void) ipf_nat_proto(&fi, nat2, IPN_UDP); 332 MUTEX_ENTER(&nat2->nat_lock); 333 ipf_nat_update(&fi, nat2); 334 MUTEX_EXIT(&nat2->nat_lock); 335 336 (void) ipf_state_add(softc, &fi, NULL, SI_W_DPORT); 337 } 338 } 339 340 ip->ip_p = swp; 341 ip->ip_len = slen; 342 ip->ip_src = swa; 343 ip->ip_dst = swb; 344 return 0; 345} 346