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