1 /* ns_input.c 6.2 85/06/01 */ 2 3 #include "param.h" 4 #include "systm.h" 5 #include "mbuf.h" 6 #include "domain.h" 7 #include "protosw.h" 8 #include "socket.h" 9 #include "socketvar.h" 10 #include "errno.h" 11 #include "time.h" 12 #include "kernel.h" 13 14 #include "../net/if.h" 15 #include "../net/route.h" 16 #include "../net/raw_cb.h" 17 18 #include "ns.h" 19 #include "ns_if.h" 20 #include "ns_pcb.h" 21 #include "idp.h" 22 #include "idp_var.h" 23 #include "ns_error.h" 24 25 /* 26 * NS initialization. 27 */ 28 union ns_host ns_thishost; 29 union ns_host ns_zerohost; 30 union ns_host ns_broadhost; 31 32 static char allones[] = {-1, -1, -1, -1, -1, -1}; 33 34 struct nspcb nspcb; 35 struct nspcb nsrawpcb; 36 37 struct ifqueue nsintrq; 38 int nsqmaxlen = IFQ_MAXLEN; 39 40 int idpcksum = 0; 41 42 ns_init() 43 { 44 ns_broadhost = * (union ns_host *) allones; 45 nspcb.nsp_next = nspcb.nsp_prev = &nspcb; 46 nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb; 47 nsintrq.ifq_maxlen = nsqmaxlen; 48 } 49 50 /* 51 * Idp input routine. Pass to next level. 52 */ 53 int nsintr_getpck = 0; 54 int nsintr_swtch = 0; 55 nsintr() 56 { 57 register struct idp *idp; 58 register struct mbuf *m; 59 struct nspcb *nsp; 60 struct mbuf *m0; 61 register int i; 62 int len, s, error; 63 char oddpacketp; 64 65 next: 66 /* 67 * Get next datagram off input queue and get IDP header 68 * in first mbuf. 69 */ 70 s = splimp(); 71 IF_DEQUEUE(&nsintrq, m); 72 splx(s); 73 nsintr_getpck++; 74 if (m == 0) 75 return; 76 if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct idp)) && 77 (m = m_pullup(m, sizeof (struct idp))) == 0) { 78 idpstat.idps_toosmall++; 79 goto next; 80 } 81 82 /* 83 * Give any raw listeners a crack at the packet 84 */ 85 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 86 struct mbuf *m1 = m_copy(m, 0, M_COPYALL); 87 if (m1) idp_input(m1, nsp); 88 } 89 90 idp = mtod(m, struct idp *); 91 len = ntohs(idp->idp_len); 92 if (oddpacketp = len & 1) { 93 len++; /* If this packet is of odd length, 94 preserve garbage byte for checksum */ 95 } 96 97 /* 98 * Check that the amount of data in the buffers 99 * is as at least much as the IDP header would have us expect. 100 * Trim mbufs if longer than we expect. 101 * Drop packet if shorter than we expect. 102 */ 103 i = -len; 104 m0 = m; 105 for (;;) { 106 i += m->m_len; 107 if (m->m_next == 0) 108 break; 109 m = m->m_next; 110 } 111 if (i != 0) { 112 if (i < 0) { 113 idpstat.idps_tooshort++; 114 m = m0; 115 goto bad; 116 } 117 if (i <= m->m_len) 118 m->m_len -= i; 119 else 120 m_adj(m0, -i); 121 } 122 m = m0; 123 if (idpcksum && ((i = idp->idp_sum)!=0xffff)) { 124 idp->idp_sum = 0; 125 if (i != (idp->idp_sum = ns_cksum(m,len))) { 126 idpstat.idps_badsum++; 127 if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host)) 128 error = NS_ERR_BADSUM; 129 else 130 error = NS_ERR_BADSUM_T; 131 ns_error(m, error, 0); 132 goto next; 133 } 134 } 135 /* 136 * Is this a directed broadcast? 137 */ 138 if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) { 139 if ((ns_netof(idp->idp_dna)!=ns_netof(idp->idp_sna)) && 140 (ns_netof(idp->idp_dna)!=-1) && (ns_netof(idp->idp_sna)!=0) 141 && (ns_netof(idp->idp_dna)!=0)) { 142 /* 143 * Look to see if I need to eat this packet. 144 * Algorithm is to forward all young packets 145 * and prematurely age any packets which will 146 * by physically broadcasted. 147 * Any very old packets eaten without forwarding 148 * would die anyway. 149 * 150 * Suggestion of Bill Nesheim, Cornell U. 151 */ 152 if(idp->idp_tc < NS_MAXHOPS) { 153 idp_forward(idp); 154 goto next; 155 } 156 } 157 /* 158 * Is this our packet? If not, forward. 159 */ 160 } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) { 161 idp_forward(idp); 162 goto next; 163 } 164 165 /* 166 * Locate pcb for datagram. 167 */ 168 nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD); 169 170 171 /* 172 * Switch out to protocol's input routine. 173 */ 174 175 nsintr_swtch++; 176 if (nsp) { 177 if (oddpacketp) { 178 m_adj(m0, -1); 179 } 180 switch (idp->idp_pt) { 181 case NSPROTO_SPP: 182 spp_input(m,nsp); 183 break; 184 case NSPROTO_ERROR: 185 ns_err_input(m); 186 break; 187 default: 188 idp_input(m,nsp); 189 } 190 } else { 191 /* don't send ERROR response for multicast packet */ 192 if (idp->idp_dna.x_host.c_host[0] & 1) 193 goto bad; 194 ns_error(m, NS_ERR_NOSOCK, 0); 195 } 196 goto next; 197 198 bad: 199 m_freem(m); 200 goto next; 201 } 202 203 u_char nsctlerrmap[PRC_NCMDS] = { 204 ECONNABORTED, ECONNABORTED, 0, 0, 205 0, 0, EHOSTDOWN, EHOSTUNREACH, 206 ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 207 EMSGSIZE, 0, 0, 0, 208 0, 0, 0, 0 209 }; 210 211 idp_ctlinput(cmd, arg) 212 int cmd; 213 caddr_t arg; 214 { 215 struct ns_addr *ns; 216 int idp_abort(); 217 int type; 218 219 if (cmd < 0 || cmd > PRC_NCMDS) 220 return; 221 if (nsctlerrmap[cmd] == 0) 222 return; /* XXX */ 223 type = NS_ERR_UNREACH_HOST; 224 if (cmd == PRC_IFDOWN) 225 ns = &((struct sockaddr_ns *)arg)->sns_addr; 226 else if (cmd == PRC_HOSTDEAD || cmd == PRC_HOSTUNREACH) 227 ns = (struct ns_addr *)arg; 228 else { 229 ns = &((struct ns_errp *)arg)->ns_err_idp.idp_dna; 230 type = ((struct ns_errp *)arg)->ns_err_num; 231 type = ntohs(type); 232 } 233 switch (type) { 234 case NS_ERR_UNREACH_HOST: 235 case NS_ERR_NOSOCK: 236 ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, 0); 237 } 238 } 239 240 int idpprintfs = 0; 241 int idpforwarding = 1; 242 /* 243 * Forward a packet. If some error occurs return the sender 244 * an error packet. Note we can't always generate a meaningful 245 * error message because the NS errors don't have a large enough repetoire 246 * of codes and types. 247 */ 248 struct route idp_droute; 249 struct route idp_sroute; 250 251 idp_forward(idp) 252 register struct idp *idp; 253 { 254 register int error, type, code; 255 struct mbuf *mcopy = NULL; 256 int agedelta = 1; 257 int flags = NS_FORWARDING; 258 int ok_there = 0; 259 int ok_back = 0; 260 261 if (idpprintfs) { 262 printf("forward: src "); 263 ns_printhost(&idp->idp_sna); 264 printf(", dst "); 265 ns_printhost(&idp->idp_dna); 266 printf("hop count %d\n", idp->idp_tc); 267 } 268 if (idpforwarding == 0) { 269 /* can't tell difference between net and host */ 270 type = NS_ERR_UNREACH_HOST, code = 0; 271 goto senderror; 272 } 273 idp->idp_tc++; 274 if (idp->idp_tc > NS_MAXHOPS) { 275 type = NS_ERR_TOO_OLD, code = 0; 276 goto senderror; 277 } 278 /* 279 * Save at most 42 bytes of the packet in case 280 * we need to generate an NS error message to the src. 281 */ 282 mcopy = m_copy(dtom(idp), 0, imin(ntohs(idp->idp_len), 42)); 283 284 if((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) { 285 type = NS_ERR_UNREACH_HOST, code = 0; 286 goto senderror; 287 } 288 /* 289 * Here we think about forwarding broadcast packets, 290 * so we try to insure that it doesn't go back out 291 * on the interface it came in on. Also, if we 292 * are going to physically broadcast this, let us 293 * age the packet so we can eat it safely the second time around. 294 */ 295 if (idp->idp_dna.x_host.c_host[0] & 0x1) { 296 struct ns_ifaddr *ia = ns_iaonnetof(idp->idp_dna.x_net); 297 struct ifnet *ifp; 298 if (ia) { 299 /* I'm gonna hafta eat this packet */ 300 agedelta += NS_MAXHOPS - idp->idp_tc; 301 idp->idp_tc = NS_MAXHOPS; 302 } 303 if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) { 304 /* error = ENETUNREACH; He'll never get it! */ 305 m_freem(dtom(idp)); 306 goto cleanup; 307 } 308 if (idp_droute.ro_rt && 309 (ifp=idp_droute.ro_rt->rt_ifp) && 310 idp_sroute.ro_rt && 311 (ifp!=idp_sroute.ro_rt->rt_ifp)) { 312 flags |= NS_ALLOWBROADCAST; 313 } else { 314 type = NS_ERR_UNREACH_HOST, code = 0; 315 goto senderror; 316 } 317 } 318 /* need to adjust checksum */ 319 if (idp->idp_sum!=0xffff) { 320 union bytes { 321 u_char c[4]; 322 u_short s[2]; 323 long l; 324 } x; 325 register int shift; 326 x.l = 0; x.c[0] = agedelta; 327 shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf; 328 x.l = idp->idp_sum + (x.l << shift); 329 x.l = x.s[0] + x.s[1]; 330 x.l = x.s[0] + x.s[1]; 331 if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l; 332 } 333 if ((error = ns_output(dtom(idp), &idp_droute, flags)) && 334 (mcopy!=NULL)) { 335 idp = mtod(mcopy, struct idp *); 336 type = NS_ERR_UNSPEC_T, code = 0; 337 switch (error) { 338 339 case ENETUNREACH: 340 case EHOSTDOWN: 341 case EHOSTUNREACH: 342 case ENETDOWN: 343 case EPERM: 344 type = NS_ERR_UNREACH_HOST; 345 break; 346 347 case EMSGSIZE: 348 type = NS_ERR_TOO_BIG; 349 code = 576; /* too hard to figure out mtu here */ 350 break; 351 352 case ENOBUFS: 353 type = NS_ERR_UNSPEC_T; 354 break; 355 } 356 } 357 senderror: 358 ns_error(dtom(idp), type, code); 359 mcopy = NULL; 360 cleanup: 361 if (ok_there) 362 idp_undo_route(&idp_droute); 363 if (ok_back) 364 idp_undo_route(&idp_sroute); 365 if (mcopy != NULL) 366 m_freem(mcopy); 367 } 368 369 idp_do_route(src, ro) 370 struct ns_addr *src; 371 struct route *ro; 372 { 373 374 struct sockaddr_ns *dst; 375 376 bzero((caddr_t)ro, sizeof (*ro)); 377 dst = (struct sockaddr_ns *)&ro->ro_dst; 378 379 dst->sns_family = AF_NS; 380 dst->sns_addr = *src; 381 rtalloc(ro); 382 if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) { 383 return(0); 384 } 385 ro->ro_rt->rt_use++; 386 return(1); 387 } 388 389 idp_undo_route(ro) 390 register struct route *ro; 391 { 392 if (ro->ro_rt) {RTFREE(ro->ro_rt);} 393 } 394 ns_watch_output(m) 395 struct mbuf *m; 396 { 397 register struct nspcb *nsp; 398 /* 399 * Give any raw listeners a crack at the packet 400 */ 401 for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) { 402 struct mbuf *m1 = m_copy(m, 0, M_COPYALL); 403 if (m1) idp_input(m1, nsp); 404 } 405 } 406