1 /* 2 * Copyright (c) 1984, 1985, 1986 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)ns_input.c 7.1 (Berkeley) 06/05/86 7 */ 8 9 #include "param.h" 10 #include "systm.h" 11 #include "mbuf.h" 12 #include "domain.h" 13 #include "protosw.h" 14 #include "socket.h" 15 #include "socketvar.h" 16 #include "errno.h" 17 #include "time.h" 18 #include "kernel.h" 19 20 #include "../net/if.h" 21 #include "../net/route.h" 22 #include "../net/raw_cb.h" 23 24 #include "ns.h" 25 #include "ns_if.h" 26 #include "ns_pcb.h" 27 #include "idp.h" 28 #include "idp_var.h" 29 #include "ns_error.h" 30 31 /* 32 * NS initialization. 33 */ 34 union ns_host ns_thishost; 35 union ns_host ns_zerohost; 36 union ns_host ns_broadhost; 37 union ns_net ns_zeronet; 38 union ns_net ns_broadnet; 39 40 static u_short allones[] = {-1, -1, -1}; 41 42 struct nspcb nspcb; 43 struct nspcb nsrawpcb; 44 45 struct ifqueue nsintrq; 46 int nsqmaxlen = IFQ_MAXLEN; 47 48 int idpcksum = 1; 49 long ns_pexseq; 50 51 ns_init() 52 { 53 extern struct timeval time; 54 55 ns_broadhost = * (union ns_host *) allones; 56 ns_broadnet = * (union ns_net *) allones; 57 nspcb.nsp_next = nspcb.nsp_prev = &nspcb; 58 nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb; 59 nsintrq.ifq_maxlen = nsqmaxlen; 60 ns_pexseq = time.tv_usec; 61 } 62 63 /* 64 * Idp input routine. Pass to next level. 65 */ 66 int nsintr_getpck = 0; 67 int nsintr_swtch = 0; 68 nsintr() 69 { 70 register struct idp *idp; 71 register struct mbuf *m; 72 register struct nspcb *nsp; 73 struct ifnet *ifp; 74 struct mbuf *m0; 75 register int i; 76 int len, s, error; 77 char oddpacketp; 78 79 next: 80 /* 81 * Get next datagram off input queue and get IDP header 82 * in first mbuf. 83 */ 84 s = splimp(); 85 IF_DEQUEUEIF(&nsintrq, m, ifp); 86 splx(s); 87 nsintr_getpck++; 88 if (m == 0) 89 return; 90 if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct idp)) && 91 (m = m_pullup(m, sizeof (struct idp))) == 0) { 92 idpstat.idps_toosmall++; 93 goto next; 94 } 95 96 /* 97 * Give any raw listeners a crack at the packet 98 */ 99 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 100 struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL); 101 if (m1) idp_input(m1, nsp, ifp); 102 } 103 104 idp = mtod(m, struct idp *); 105 len = ntohs(idp->idp_len); 106 if (oddpacketp = len & 1) { 107 len++; /* If this packet is of odd length, 108 preserve garbage byte for checksum */ 109 } 110 111 /* 112 * Check that the amount of data in the buffers 113 * is as at least much as the IDP header would have us expect. 114 * Trim mbufs if longer than we expect. 115 * Drop packet if shorter than we expect. 116 */ 117 i = -len; 118 m0 = m; 119 for (;;) { 120 i += m->m_len; 121 if (m->m_next == 0) 122 break; 123 m = m->m_next; 124 } 125 if (i != 0) { 126 if (i < 0) { 127 idpstat.idps_tooshort++; 128 m = m0; 129 goto bad; 130 } 131 if (i <= m->m_len) 132 m->m_len -= i; 133 else 134 m_adj(m0, -i); 135 } 136 m = m0; 137 if (idpcksum && ((i = idp->idp_sum)!=0xffff)) { 138 idp->idp_sum = 0; 139 if (i != (idp->idp_sum = ns_cksum(m,len))) { 140 idpstat.idps_badsum++; 141 idp->idp_sum = i; 142 if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host)) 143 error = NS_ERR_BADSUM; 144 else 145 error = NS_ERR_BADSUM_T; 146 ns_error(m, error, 0); 147 goto next; 148 } 149 } 150 /* 151 * Is this a directed broadcast? 152 */ 153 if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) { 154 if ((!ns_neteq(idp->idp_dna, idp->idp_sna)) && 155 (!ns_neteqnn(idp->idp_dna.x_net, ns_broadnet)) && 156 (!ns_neteqnn(idp->idp_sna.x_net, ns_zeronet)) && 157 (!ns_neteqnn(idp->idp_dna.x_net, ns_zeronet)) ) { 158 /* 159 * Look to see if I need to eat this packet. 160 * Algorithm is to forward all young packets 161 * and prematurely age any packets which will 162 * by physically broadcasted. 163 * Any very old packets eaten without forwarding 164 * would die anyway. 165 * 166 * Suggestion of Bill Nesheim, Cornell U. 167 */ 168 if (idp->idp_tc < NS_MAXHOPS) { 169 idp_forward(idp); 170 goto next; 171 } 172 } 173 /* 174 * Is this our packet? If not, forward. 175 */ 176 } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) { 177 idp_forward(idp); 178 goto next; 179 } 180 /* 181 * Locate pcb for datagram. 182 */ 183 nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD); 184 /* 185 * Switch out to protocol's input routine. 186 */ 187 nsintr_swtch++; 188 if (nsp) { 189 if (oddpacketp) { 190 m_adj(m0, -1); 191 } 192 if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0) 193 switch (idp->idp_pt) { 194 195 case NSPROTO_SPP: 196 spp_input(m, nsp, ifp); 197 goto next; 198 199 case NSPROTO_ERROR: 200 ns_err_input(m); 201 goto next; 202 } 203 idp_input(m, nsp, ifp); 204 } else { 205 ns_error(m, NS_ERR_NOSOCK, 0); 206 } 207 goto next; 208 209 bad: 210 m_freem(m); 211 goto next; 212 } 213 214 u_char nsctlerrmap[PRC_NCMDS] = { 215 ECONNABORTED, ECONNABORTED, 0, 0, 216 0, 0, EHOSTDOWN, EHOSTUNREACH, 217 ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 218 EMSGSIZE, 0, 0, 0, 219 0, 0, 0, 0 220 }; 221 222 idp_donosocks = 1; 223 224 idp_ctlinput(cmd, arg) 225 int cmd; 226 caddr_t arg; 227 { 228 struct ns_addr *ns; 229 struct nspcb *nsp; 230 struct ns_errp *errp; 231 int idp_abort(); 232 extern struct nspcb *idp_drop(); 233 int type; 234 235 if (cmd < 0 || cmd > PRC_NCMDS) 236 return; 237 if (nsctlerrmap[cmd] == 0) 238 return; /* XXX */ 239 type = NS_ERR_UNREACH_HOST; 240 switch (cmd) { 241 struct sockaddr_ns *sns; 242 243 case PRC_IFDOWN: 244 case PRC_HOSTDEAD: 245 case PRC_HOSTUNREACH: 246 sns = (struct sockaddr_ns *)arg; 247 if (sns->sns_family != AF_INET) 248 return; 249 ns = &sns->sns_addr; 250 break; 251 252 default: 253 errp = (struct ns_errp *)arg; 254 ns = &errp->ns_err_idp.idp_dna; 255 type = errp->ns_err_num; 256 type = ntohs((u_short)type); 257 } 258 switch (type) { 259 260 case NS_ERR_UNREACH_HOST: 261 ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0); 262 break; 263 264 case NS_ERR_NOSOCK: 265 nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port, 266 NS_WILDCARD); 267 if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr)) 268 (void) idp_drop(nsp, (int)nsctlerrmap[cmd]); 269 } 270 } 271 272 int idpprintfs = 0; 273 int idpforwarding = 1; 274 /* 275 * Forward a packet. If some error occurs return the sender 276 * an error packet. Note we can't always generate a meaningful 277 * error message because the NS errors don't have a large enough repetoire 278 * of codes and types. 279 */ 280 struct route idp_droute; 281 struct route idp_sroute; 282 283 idp_forward(idp) 284 register struct idp *idp; 285 { 286 register int error, type, code; 287 struct mbuf *mcopy = NULL; 288 int agedelta = 1; 289 int flags = NS_FORWARDING; 290 int ok_there = 0; 291 int ok_back = 0; 292 293 if (idpprintfs) { 294 printf("forward: src "); 295 ns_printhost(&idp->idp_sna); 296 printf(", dst "); 297 ns_printhost(&idp->idp_dna); 298 printf("hop count %d\n", idp->idp_tc); 299 } 300 if (idpforwarding == 0) { 301 /* can't tell difference between net and host */ 302 type = NS_ERR_UNREACH_HOST, code = 0; 303 goto senderror; 304 } 305 idp->idp_tc++; 306 if (idp->idp_tc > NS_MAXHOPS) { 307 type = NS_ERR_TOO_OLD, code = 0; 308 goto senderror; 309 } 310 /* 311 * Save at most 42 bytes of the packet in case 312 * we need to generate an NS error message to the src. 313 */ 314 mcopy = m_copy(dtom(idp), 0, imin((int)ntohs(idp->idp_len), 42)); 315 316 if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) { 317 type = NS_ERR_UNREACH_HOST, code = 0; 318 goto senderror; 319 } 320 /* 321 * Here we think about forwarding broadcast packets, 322 * so we try to insure that it doesn't go back out 323 * on the interface it came in on. Also, if we 324 * are going to physically broadcast this, let us 325 * age the packet so we can eat it safely the second time around. 326 */ 327 if (idp->idp_dna.x_host.c_host[0] & 0x1) { 328 struct ns_ifaddr *ia = ns_iaonnetof(&idp->idp_dna); 329 struct ifnet *ifp; 330 if (ia) { 331 /* I'm gonna hafta eat this packet */ 332 agedelta += NS_MAXHOPS - idp->idp_tc; 333 idp->idp_tc = NS_MAXHOPS; 334 } 335 if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) { 336 /* error = ENETUNREACH; He'll never get it! */ 337 m_freem(dtom(idp)); 338 goto cleanup; 339 } 340 if (idp_droute.ro_rt && 341 (ifp=idp_droute.ro_rt->rt_ifp) && 342 idp_sroute.ro_rt && 343 (ifp!=idp_sroute.ro_rt->rt_ifp)) { 344 flags |= NS_ALLOWBROADCAST; 345 } else { 346 type = NS_ERR_UNREACH_HOST, code = 0; 347 goto senderror; 348 } 349 } 350 /* need to adjust checksum */ 351 if (idp->idp_sum!=0xffff) { 352 union bytes { 353 u_char c[4]; 354 u_short s[2]; 355 long l; 356 } x; 357 register int shift; 358 x.l = 0; x.c[0] = agedelta; 359 shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf; 360 x.l = idp->idp_sum + (x.l << shift); 361 x.l = x.s[0] + x.s[1]; 362 x.l = x.s[0] + x.s[1]; 363 if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l; 364 } 365 if ((error = ns_output(dtom(idp), &idp_droute, flags)) && 366 (mcopy!=NULL)) { 367 idp = mtod(mcopy, struct idp *); 368 type = NS_ERR_UNSPEC_T, code = 0; 369 switch (error) { 370 371 case ENETUNREACH: 372 case EHOSTDOWN: 373 case EHOSTUNREACH: 374 case ENETDOWN: 375 case EPERM: 376 type = NS_ERR_UNREACH_HOST; 377 break; 378 379 case EMSGSIZE: 380 type = NS_ERR_TOO_BIG; 381 code = 576; /* too hard to figure out mtu here */ 382 break; 383 384 case ENOBUFS: 385 type = NS_ERR_UNSPEC_T; 386 break; 387 } 388 mcopy = NULL; 389 senderror: 390 ns_error(dtom(idp), type, code); 391 } 392 cleanup: 393 if (ok_there) 394 idp_undo_route(&idp_droute); 395 if (ok_back) 396 idp_undo_route(&idp_sroute); 397 if (mcopy != NULL) 398 m_freem(mcopy); 399 } 400 401 idp_do_route(src, ro) 402 struct ns_addr *src; 403 struct route *ro; 404 { 405 406 struct sockaddr_ns *dst; 407 408 bzero((caddr_t)ro, sizeof (*ro)); 409 dst = (struct sockaddr_ns *)&ro->ro_dst; 410 411 dst->sns_family = AF_NS; 412 dst->sns_addr = *src; 413 dst->sns_addr.x_port = 0; 414 rtalloc(ro); 415 if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) { 416 return (0); 417 } 418 ro->ro_rt->rt_use++; 419 return (1); 420 } 421 422 idp_undo_route(ro) 423 register struct route *ro; 424 { 425 if (ro->ro_rt) {RTFREE(ro->ro_rt);} 426 } 427 static union ns_net 428 ns_zeronet; 429 430 ns_watch_output(m, ifp) 431 struct mbuf *m; 432 struct ifnet *ifp; 433 { 434 register struct nspcb *nsp; 435 register struct ifaddr *ia; 436 /* 437 * Give any raw listeners a crack at the packet 438 */ 439 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 440 struct mbuf *m0 = m_copy(m, 0, (int)M_COPYALL); 441 if (m0) { 442 struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA); 443 444 if(m1 == NULL) 445 m_freem(m0); 446 else { 447 register struct idp *idp; 448 449 m1->m_off = MMINOFF; 450 m1->m_len = sizeof (*idp); 451 m1->m_next = m0; 452 idp = mtod(m1, struct idp *); 453 idp->idp_sna.x_net = ns_zeronet; 454 idp->idp_sna.x_host = ns_thishost; 455 if (ifp && (ifp->if_flags & IFF_POINTOPOINT)) 456 for(ia = ifp->if_addrlist; ia; 457 ia = ia->ifa_next) { 458 if (ia->ifa_addr.sa_family==AF_NS) { 459 idp->idp_sna = 460 satons_addr(ia->ifa_dstaddr); 461 break; 462 } 463 } 464 idp->idp_len = 0xffff; 465 idp_input(m1, nsp, ifp); 466 } 467 } 468 } 469 } 470