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 6.3 (Berkeley) 06/08/85 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 = 0; 47 48 ns_init() 49 { 50 ns_broadhost = * (union ns_host *) allones; 51 nspcb.nsp_next = nspcb.nsp_prev = &nspcb; 52 nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb; 53 nsintrq.ifq_maxlen = nsqmaxlen; 54 } 55 56 /* 57 * Idp input routine. Pass to next level. 58 */ 59 int nsintr_getpck = 0; 60 int nsintr_swtch = 0; 61 nsintr() 62 { 63 register struct idp *idp; 64 register struct mbuf *m; 65 struct nspcb *nsp; 66 struct mbuf *m0; 67 register int i; 68 int len, s, error; 69 char oddpacketp; 70 71 next: 72 /* 73 * Get next datagram off input queue and get IDP header 74 * in first mbuf. 75 */ 76 s = splimp(); 77 IF_DEQUEUE(&nsintrq, m); 78 splx(s); 79 nsintr_getpck++; 80 if (m == 0) 81 return; 82 if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct idp)) && 83 (m = m_pullup(m, sizeof (struct idp))) == 0) { 84 idpstat.idps_toosmall++; 85 goto next; 86 } 87 88 /* 89 * Give any raw listeners a crack at the packet 90 */ 91 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 92 struct mbuf *m1 = m_copy(m, 0, M_COPYALL); 93 if (m1) idp_input(m1, nsp); 94 } 95 96 idp = mtod(m, struct idp *); 97 len = ntohs(idp->idp_len); 98 if (oddpacketp = len & 1) { 99 len++; /* If this packet is of odd length, 100 preserve garbage byte for checksum */ 101 } 102 103 /* 104 * Check that the amount of data in the buffers 105 * is as at least much as the IDP header would have us expect. 106 * Trim mbufs if longer than we expect. 107 * Drop packet if shorter than we expect. 108 */ 109 i = -len; 110 m0 = m; 111 for (;;) { 112 i += m->m_len; 113 if (m->m_next == 0) 114 break; 115 m = m->m_next; 116 } 117 if (i != 0) { 118 if (i < 0) { 119 idpstat.idps_tooshort++; 120 m = m0; 121 goto bad; 122 } 123 if (i <= m->m_len) 124 m->m_len -= i; 125 else 126 m_adj(m0, -i); 127 } 128 m = m0; 129 if (idpcksum && ((i = idp->idp_sum)!=0xffff)) { 130 idp->idp_sum = 0; 131 if (i != (idp->idp_sum = ns_cksum(m,len))) { 132 idpstat.idps_badsum++; 133 if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host)) 134 error = NS_ERR_BADSUM; 135 else 136 error = NS_ERR_BADSUM_T; 137 ns_error(m, error, 0); 138 goto next; 139 } 140 } 141 /* 142 * Is this a directed broadcast? 143 */ 144 if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) { 145 if ((ns_netof(idp->idp_dna)!=ns_netof(idp->idp_sna)) && 146 (ns_netof(idp->idp_dna)!=-1) && (ns_netof(idp->idp_sna)!=0) 147 && (ns_netof(idp->idp_dna)!=0)) { 148 /* 149 * Look to see if I need to eat this packet. 150 * Algorithm is to forward all young packets 151 * and prematurely age any packets which will 152 * by physically broadcasted. 153 * Any very old packets eaten without forwarding 154 * would die anyway. 155 * 156 * Suggestion of Bill Nesheim, Cornell U. 157 */ 158 if(idp->idp_tc < NS_MAXHOPS) { 159 idp_forward(idp); 160 goto next; 161 } 162 } 163 /* 164 * Is this our packet? If not, forward. 165 */ 166 } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) { 167 idp_forward(idp); 168 goto next; 169 } 170 171 /* 172 * Locate pcb for datagram. 173 */ 174 nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD); 175 176 177 /* 178 * Switch out to protocol's input routine. 179 */ 180 181 nsintr_swtch++; 182 if (nsp) { 183 if (oddpacketp) { 184 m_adj(m0, -1); 185 } 186 switch (idp->idp_pt) { 187 case NSPROTO_SPP: 188 spp_input(m,nsp); 189 break; 190 case NSPROTO_ERROR: 191 ns_err_input(m); 192 break; 193 default: 194 idp_input(m,nsp); 195 } 196 } else { 197 /* don't send ERROR response for multicast packet */ 198 if (idp->idp_dna.x_host.c_host[0] & 1) 199 goto bad; 200 ns_error(m, NS_ERR_NOSOCK, 0); 201 } 202 goto next; 203 204 bad: 205 m_freem(m); 206 goto next; 207 } 208 209 u_char nsctlerrmap[PRC_NCMDS] = { 210 ECONNABORTED, ECONNABORTED, 0, 0, 211 0, 0, EHOSTDOWN, EHOSTUNREACH, 212 ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 213 EMSGSIZE, 0, 0, 0, 214 0, 0, 0, 0 215 }; 216 217 idp_ctlinput(cmd, arg) 218 int cmd; 219 caddr_t arg; 220 { 221 struct ns_addr *ns; 222 int idp_abort(); 223 int type; 224 225 if (cmd < 0 || cmd > PRC_NCMDS) 226 return; 227 if (nsctlerrmap[cmd] == 0) 228 return; /* XXX */ 229 type = NS_ERR_UNREACH_HOST; 230 if (cmd == PRC_IFDOWN) 231 ns = &((struct sockaddr_ns *)arg)->sns_addr; 232 else if (cmd == PRC_HOSTDEAD || cmd == PRC_HOSTUNREACH) 233 ns = (struct ns_addr *)arg; 234 else { 235 ns = &((struct ns_errp *)arg)->ns_err_idp.idp_dna; 236 type = ((struct ns_errp *)arg)->ns_err_num; 237 type = ntohs(type); 238 } 239 switch (type) { 240 case NS_ERR_UNREACH_HOST: 241 case NS_ERR_NOSOCK: 242 ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, 0); 243 } 244 } 245 246 int idpprintfs = 0; 247 int idpforwarding = 1; 248 /* 249 * Forward a packet. If some error occurs return the sender 250 * an error packet. Note we can't always generate a meaningful 251 * error message because the NS errors don't have a large enough repetoire 252 * of codes and types. 253 */ 254 struct route idp_droute; 255 struct route idp_sroute; 256 257 idp_forward(idp) 258 register struct idp *idp; 259 { 260 register int error, type, code; 261 struct mbuf *mcopy = NULL; 262 int agedelta = 1; 263 int flags = NS_FORWARDING; 264 int ok_there = 0; 265 int ok_back = 0; 266 267 if (idpprintfs) { 268 printf("forward: src "); 269 ns_printhost(&idp->idp_sna); 270 printf(", dst "); 271 ns_printhost(&idp->idp_dna); 272 printf("hop count %d\n", idp->idp_tc); 273 } 274 if (idpforwarding == 0) { 275 /* can't tell difference between net and host */ 276 type = NS_ERR_UNREACH_HOST, code = 0; 277 goto senderror; 278 } 279 idp->idp_tc++; 280 if (idp->idp_tc > NS_MAXHOPS) { 281 type = NS_ERR_TOO_OLD, code = 0; 282 goto senderror; 283 } 284 /* 285 * Save at most 42 bytes of the packet in case 286 * we need to generate an NS error message to the src. 287 */ 288 mcopy = m_copy(dtom(idp), 0, imin(ntohs(idp->idp_len), 42)); 289 290 if((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) { 291 type = NS_ERR_UNREACH_HOST, code = 0; 292 goto senderror; 293 } 294 /* 295 * Here we think about forwarding broadcast packets, 296 * so we try to insure that it doesn't go back out 297 * on the interface it came in on. Also, if we 298 * are going to physically broadcast this, let us 299 * age the packet so we can eat it safely the second time around. 300 */ 301 if (idp->idp_dna.x_host.c_host[0] & 0x1) { 302 struct ns_ifaddr *ia = ns_iaonnetof(idp->idp_dna.x_net); 303 struct ifnet *ifp; 304 if (ia) { 305 /* I'm gonna hafta eat this packet */ 306 agedelta += NS_MAXHOPS - idp->idp_tc; 307 idp->idp_tc = NS_MAXHOPS; 308 } 309 if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) { 310 /* error = ENETUNREACH; He'll never get it! */ 311 m_freem(dtom(idp)); 312 goto cleanup; 313 } 314 if (idp_droute.ro_rt && 315 (ifp=idp_droute.ro_rt->rt_ifp) && 316 idp_sroute.ro_rt && 317 (ifp!=idp_sroute.ro_rt->rt_ifp)) { 318 flags |= NS_ALLOWBROADCAST; 319 } else { 320 type = NS_ERR_UNREACH_HOST, code = 0; 321 goto senderror; 322 } 323 } 324 /* need to adjust checksum */ 325 if (idp->idp_sum!=0xffff) { 326 union bytes { 327 u_char c[4]; 328 u_short s[2]; 329 long l; 330 } x; 331 register int shift; 332 x.l = 0; x.c[0] = agedelta; 333 shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf; 334 x.l = idp->idp_sum + (x.l << shift); 335 x.l = x.s[0] + x.s[1]; 336 x.l = x.s[0] + x.s[1]; 337 if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l; 338 } 339 if ((error = ns_output(dtom(idp), &idp_droute, flags)) && 340 (mcopy!=NULL)) { 341 idp = mtod(mcopy, struct idp *); 342 type = NS_ERR_UNSPEC_T, code = 0; 343 switch (error) { 344 345 case ENETUNREACH: 346 case EHOSTDOWN: 347 case EHOSTUNREACH: 348 case ENETDOWN: 349 case EPERM: 350 type = NS_ERR_UNREACH_HOST; 351 break; 352 353 case EMSGSIZE: 354 type = NS_ERR_TOO_BIG; 355 code = 576; /* too hard to figure out mtu here */ 356 break; 357 358 case ENOBUFS: 359 type = NS_ERR_UNSPEC_T; 360 break; 361 } 362 } 363 senderror: 364 ns_error(dtom(idp), type, code); 365 mcopy = NULL; 366 cleanup: 367 if (ok_there) 368 idp_undo_route(&idp_droute); 369 if (ok_back) 370 idp_undo_route(&idp_sroute); 371 if (mcopy != NULL) 372 m_freem(mcopy); 373 } 374 375 idp_do_route(src, ro) 376 struct ns_addr *src; 377 struct route *ro; 378 { 379 380 struct sockaddr_ns *dst; 381 382 bzero((caddr_t)ro, sizeof (*ro)); 383 dst = (struct sockaddr_ns *)&ro->ro_dst; 384 385 dst->sns_family = AF_NS; 386 dst->sns_addr = *src; 387 rtalloc(ro); 388 if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) { 389 return(0); 390 } 391 ro->ro_rt->rt_use++; 392 return(1); 393 } 394 395 idp_undo_route(ro) 396 register struct route *ro; 397 { 398 if (ro->ro_rt) {RTFREE(ro->ro_rt);} 399 } 400 ns_watch_output(m) 401 struct mbuf *m; 402 { 403 register struct nspcb *nsp; 404 /* 405 * Give any raw listeners a crack at the packet 406 */ 407 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 408 struct mbuf *m1 = m_copy(m, 0, M_COPYALL); 409 if (m1) idp_input(m1, nsp); 410 } 411 } 412