1 /* 2 * Copyright (c) 1982 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 6.10 (Berkeley) 09/06/85 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 38 static char allones[] = {-1, -1, -1, -1, -1, -1}; 39 40 struct nspcb nspcb; 41 struct nspcb nsrawpcb; 42 43 struct ifqueue nsintrq; 44 int nsqmaxlen = IFQ_MAXLEN; 45 46 int idpcksum = 1; 47 long ns_pexseq; 48 49 ns_init() 50 { 51 extern struct timeval time; 52 53 ns_broadhost = * (union ns_host *) allones; 54 nspcb.nsp_next = nspcb.nsp_prev = &nspcb; 55 nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb; 56 nsintrq.ifq_maxlen = nsqmaxlen; 57 ns_pexseq = time.tv_usec; 58 } 59 60 /* 61 * Idp input routine. Pass to next level. 62 */ 63 int nsintr_getpck = 0; 64 int nsintr_swtch = 0; 65 nsintr() 66 { 67 register struct idp *idp; 68 register struct mbuf *m; 69 register struct nspcb *nsp; 70 struct ifnet *ifp; 71 struct mbuf *m0; 72 register int i; 73 int len, s, error; 74 char oddpacketp; 75 76 next: 77 /* 78 * Get next datagram off input queue and get IDP header 79 * in first mbuf. 80 */ 81 s = splimp(); 82 IF_DEQUEUEIF(&nsintrq, m, ifp); 83 splx(s); 84 nsintr_getpck++; 85 if (m == 0) 86 return; 87 if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct idp)) && 88 (m = m_pullup(m, sizeof (struct idp))) == 0) { 89 idpstat.idps_toosmall++; 90 goto next; 91 } 92 93 /* 94 * Give any raw listeners a crack at the packet 95 */ 96 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 97 struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL); 98 if (m1) idp_input(m1, nsp, ifp); 99 } 100 101 idp = mtod(m, struct idp *); 102 len = ntohs(idp->idp_len); 103 if (oddpacketp = len & 1) { 104 len++; /* If this packet is of odd length, 105 preserve garbage byte for checksum */ 106 } 107 108 /* 109 * Check that the amount of data in the buffers 110 * is as at least much as the IDP header would have us expect. 111 * Trim mbufs if longer than we expect. 112 * Drop packet if shorter than we expect. 113 */ 114 i = -len; 115 m0 = m; 116 for (;;) { 117 i += m->m_len; 118 if (m->m_next == 0) 119 break; 120 m = m->m_next; 121 } 122 if (i != 0) { 123 if (i < 0) { 124 idpstat.idps_tooshort++; 125 m = m0; 126 goto bad; 127 } 128 if (i <= m->m_len) 129 m->m_len -= i; 130 else 131 m_adj(m0, -i); 132 } 133 m = m0; 134 if (idpcksum && ((i = idp->idp_sum)!=0xffff)) { 135 idp->idp_sum = 0; 136 if (i != (idp->idp_sum = ns_cksum(m,len))) { 137 idpstat.idps_badsum++; 138 idp->idp_sum = i; 139 if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host)) 140 error = NS_ERR_BADSUM; 141 else 142 error = NS_ERR_BADSUM_T; 143 ns_error(m, error, 0); 144 goto next; 145 } 146 } 147 /* 148 * Is this a directed broadcast? 149 */ 150 if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) { 151 if ((ns_netof(idp->idp_dna)!=ns_netof(idp->idp_sna)) && 152 (ns_netof(idp->idp_dna)!=-1) && (ns_netof(idp->idp_sna)!=0) 153 && (ns_netof(idp->idp_dna)!=0)) { 154 /* 155 * Look to see if I need to eat this packet. 156 * Algorithm is to forward all young packets 157 * and prematurely age any packets which will 158 * by physically broadcasted. 159 * Any very old packets eaten without forwarding 160 * would die anyway. 161 * 162 * Suggestion of Bill Nesheim, Cornell U. 163 */ 164 if (idp->idp_tc < NS_MAXHOPS) { 165 idp_forward(idp); 166 goto next; 167 } 168 } 169 /* 170 * Is this our packet? If not, forward. 171 */ 172 } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) { 173 idp_forward(idp); 174 goto next; 175 } 176 /* 177 * Locate pcb for datagram. 178 */ 179 nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD); 180 /* 181 * Switch out to protocol's input routine. 182 */ 183 nsintr_swtch++; 184 if (nsp) { 185 if (oddpacketp) { 186 m_adj(m0, -1); 187 } 188 if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0) 189 switch (idp->idp_pt) { 190 191 case NSPROTO_SPP: 192 spp_input(m, nsp, ifp); 193 goto next; 194 195 case NSPROTO_ERROR: 196 ns_err_input(m); 197 goto next; 198 } 199 idp_input(m, nsp, ifp); 200 } else { 201 ns_error(m, NS_ERR_NOSOCK, 0); 202 } 203 goto next; 204 205 bad: 206 m_freem(m); 207 goto next; 208 } 209 210 u_char nsctlerrmap[PRC_NCMDS] = { 211 ECONNABORTED, ECONNABORTED, 0, 0, 212 0, 0, EHOSTDOWN, EHOSTUNREACH, 213 ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 214 EMSGSIZE, 0, 0, 0, 215 0, 0, 0, 0 216 }; 217 218 idp_donosocks = 1; 219 220 idp_ctlinput(cmd, arg) 221 int cmd; 222 caddr_t arg; 223 { 224 struct ns_addr *ns; 225 struct nspcb *nsp; 226 struct ns_errp *errp; 227 int idp_abort(); 228 extern struct nspcb *idp_drop(); 229 int type; 230 231 if (cmd < 0 || cmd > PRC_NCMDS) 232 return; 233 if (nsctlerrmap[cmd] == 0) 234 return; /* XXX */ 235 type = NS_ERR_UNREACH_HOST; 236 switch (cmd) { 237 struct sockaddr_ns *sns; 238 239 case PRC_IFDOWN: 240 case PRC_HOSTDEAD: 241 case PRC_HOSTUNREACH: 242 sns = (struct sockaddr_ns *)arg; 243 if (sns->sns_family != AF_INET) 244 return; 245 ns = &sns->sns_addr; 246 break; 247 248 default: 249 errp = (struct ns_errp *)arg; 250 ns = &errp->ns_err_idp.idp_dna; 251 type = errp->ns_err_num; 252 type = ntohs((u_short)type); 253 } 254 switch (type) { 255 256 case NS_ERR_UNREACH_HOST: 257 ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0); 258 break; 259 260 case NS_ERR_NOSOCK: 261 nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port, 262 NS_WILDCARD); 263 if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr)) 264 (void) idp_drop(nsp, (int)nsctlerrmap[cmd]); 265 } 266 } 267 268 int idpprintfs = 0; 269 int idpforwarding = 1; 270 /* 271 * Forward a packet. If some error occurs return the sender 272 * an error packet. Note we can't always generate a meaningful 273 * error message because the NS errors don't have a large enough repetoire 274 * of codes and types. 275 */ 276 struct route idp_droute; 277 struct route idp_sroute; 278 279 idp_forward(idp) 280 register struct idp *idp; 281 { 282 register int error, type, code; 283 struct mbuf *mcopy = NULL; 284 int agedelta = 1; 285 int flags = NS_FORWARDING; 286 int ok_there = 0; 287 int ok_back = 0; 288 289 if (idpprintfs) { 290 printf("forward: src "); 291 ns_printhost(&idp->idp_sna); 292 printf(", dst "); 293 ns_printhost(&idp->idp_dna); 294 printf("hop count %d\n", idp->idp_tc); 295 } 296 if (idpforwarding == 0) { 297 /* can't tell difference between net and host */ 298 type = NS_ERR_UNREACH_HOST, code = 0; 299 goto senderror; 300 } 301 idp->idp_tc++; 302 if (idp->idp_tc > NS_MAXHOPS) { 303 type = NS_ERR_TOO_OLD, code = 0; 304 goto senderror; 305 } 306 /* 307 * Save at most 42 bytes of the packet in case 308 * we need to generate an NS error message to the src. 309 */ 310 mcopy = m_copy(dtom(idp), 0, imin(ntohs(idp->idp_len), 42)); 311 312 if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) { 313 type = NS_ERR_UNREACH_HOST, code = 0; 314 goto senderror; 315 } 316 /* 317 * Here we think about forwarding broadcast packets, 318 * so we try to insure that it doesn't go back out 319 * on the interface it came in on. Also, if we 320 * are going to physically broadcast this, let us 321 * age the packet so we can eat it safely the second time around. 322 */ 323 if (idp->idp_dna.x_host.c_host[0] & 0x1) { 324 struct ns_ifaddr *ia = ns_iaonnetof(idp->idp_dna.x_net); 325 struct ifnet *ifp; 326 if (ia) { 327 /* I'm gonna hafta eat this packet */ 328 agedelta += NS_MAXHOPS - idp->idp_tc; 329 idp->idp_tc = NS_MAXHOPS; 330 } 331 if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) { 332 /* error = ENETUNREACH; He'll never get it! */ 333 m_freem(dtom(idp)); 334 goto cleanup; 335 } 336 if (idp_droute.ro_rt && 337 (ifp=idp_droute.ro_rt->rt_ifp) && 338 idp_sroute.ro_rt && 339 (ifp!=idp_sroute.ro_rt->rt_ifp)) { 340 flags |= NS_ALLOWBROADCAST; 341 } else { 342 type = NS_ERR_UNREACH_HOST, code = 0; 343 goto senderror; 344 } 345 } 346 /* need to adjust checksum */ 347 if (idp->idp_sum!=0xffff) { 348 union bytes { 349 u_char c[4]; 350 u_short s[2]; 351 long l; 352 } x; 353 register int shift; 354 x.l = 0; x.c[0] = agedelta; 355 shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf; 356 x.l = idp->idp_sum + (x.l << shift); 357 x.l = x.s[0] + x.s[1]; 358 x.l = x.s[0] + x.s[1]; 359 if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l; 360 } 361 if ((error = ns_output(dtom(idp), &idp_droute, flags)) && 362 (mcopy!=NULL)) { 363 idp = mtod(mcopy, struct idp *); 364 type = NS_ERR_UNSPEC_T, code = 0; 365 switch (error) { 366 367 case ENETUNREACH: 368 case EHOSTDOWN: 369 case EHOSTUNREACH: 370 case ENETDOWN: 371 case EPERM: 372 type = NS_ERR_UNREACH_HOST; 373 break; 374 375 case EMSGSIZE: 376 type = NS_ERR_TOO_BIG; 377 code = 576; /* too hard to figure out mtu here */ 378 break; 379 380 case ENOBUFS: 381 type = NS_ERR_UNSPEC_T; 382 break; 383 } 384 mcopy = NULL; 385 senderror: 386 ns_error(dtom(idp), type, code); 387 } 388 cleanup: 389 if (ok_there) 390 idp_undo_route(&idp_droute); 391 if (ok_back) 392 idp_undo_route(&idp_sroute); 393 if (mcopy != NULL) 394 m_freem(mcopy); 395 } 396 397 idp_do_route(src, ro) 398 struct ns_addr *src; 399 struct route *ro; 400 { 401 402 struct sockaddr_ns *dst; 403 404 bzero((caddr_t)ro, sizeof (*ro)); 405 dst = (struct sockaddr_ns *)&ro->ro_dst; 406 407 dst->sns_family = AF_NS; 408 dst->sns_addr = *src; 409 dst->sns_addr.x_port = 0; 410 rtalloc(ro); 411 if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) { 412 return (0); 413 } 414 ro->ro_rt->rt_use++; 415 return (1); 416 } 417 418 idp_undo_route(ro) 419 register struct route *ro; 420 { 421 if (ro->ro_rt) {RTFREE(ro->ro_rt);} 422 } 423 ns_watch_output(m) 424 struct mbuf *m; 425 { 426 register struct nspcb *nsp; 427 /* 428 * Give any raw listeners a crack at the packet 429 */ 430 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 431 struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL); 432 if (m1) idp_input(m1, nsp); 433 } 434 } 435