1 /** 2 * @file 3 * This is the IPv4 layer implementation for incoming and outgoing IP traffic. 4 * 5 * @see ip_frag.c 6 * 7 */ 8 9 /* 10 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 11 * All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without modification, 14 * are permitted provided that the following conditions are met: 15 * 16 * 1. Redistributions of source code must retain the above copyright notice, 17 * this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright notice, 19 * this list of conditions and the following disclaimer in the documentation 20 * and/or other materials provided with the distribution. 21 * 3. The name of the author may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 27 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 29 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 33 * OF SUCH DAMAGE. 34 * 35 * This file is part of the lwIP TCP/IP stack. 36 * 37 * Author: Adam Dunkels <adam (at) sics.se> 38 * 39 */ 40 41 #include "lwip/opt.h" 42 #include "lwip/ip.h" 43 #include "lwip/def.h" 44 #include "lwip/mem.h" 45 #include "lwip/ip_frag.h" 46 #include "lwip/inet_chksum.h" 47 #include "lwip/netif.h" 48 #include "lwip/icmp.h" 49 #include "lwip/igmp.h" 50 #include "lwip/raw.h" 51 #include "lwip/udp.h" 52 #include "lwip/tcp_impl.h" 53 #include "lwip/snmp.h" 54 #include "lwip/dhcp.h" 55 #include "lwip/autoip.h" 56 #include "lwip/stats.h" 57 #include "arch/perf.h" 58 59 #include <string.h> 60 61 /** Set this to 0 in the rare case of wanting to call an extra function to 62 * generate the IP checksum (in contrast to calculating it on-the-fly). */ 63 #ifndef LWIP_INLINE_IP_CHKSUM 64 #define LWIP_INLINE_IP_CHKSUM 1 65 #endif 66 #if LWIP_INLINE_IP_CHKSUM && CHECKSUM_GEN_IP 67 #define CHECKSUM_GEN_IP_INLINE 1 68 #else 69 #define CHECKSUM_GEN_IP_INLINE 0 70 #endif 71 72 #if LWIP_DHCP || defined(LWIP_IP_ACCEPT_UDP_PORT) 73 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 1 74 75 /** Some defines for DHCP to let link-layer-addressed packets through while the 76 * netif is down. 77 * To use this in your own application/protocol, define LWIP_IP_ACCEPT_UDP_PORT 78 * to return 1 if the port is accepted and 0 if the port is not accepted. 79 */ 80 #if LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) 81 /* accept DHCP client port and custom port */ 82 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (((port) == PP_NTOHS(DHCP_CLIENT_PORT)) \ 83 || (LWIP_IP_ACCEPT_UDP_PORT(port))) 84 #elif defined(LWIP_IP_ACCEPT_UDP_PORT) /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */ 85 /* accept custom port only */ 86 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (LWIP_IP_ACCEPT_UDP_PORT(dst_port)) 87 #else /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */ 88 /* accept DHCP client port only */ 89 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) ((port) == PP_NTOHS(DHCP_CLIENT_PORT)) 90 #endif /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */ 91 92 #else /* LWIP_DHCP */ 93 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 0 94 #endif /* LWIP_DHCP */ 95 96 /** 97 * The interface that provided the packet for the current callback 98 * invocation. 99 */ 100 struct netif *current_netif; 101 102 /** 103 * Header of the input packet currently being processed. 104 */ 105 const struct ip_hdr *current_header; 106 /** Source IP address of current_header */ 107 ip_addr_t current_iphdr_src; 108 /** Destination IP address of current_header */ 109 ip_addr_t current_iphdr_dest; 110 111 /** The IP header ID of the next outgoing IP packet */ 112 static u16_t ip_id; 113 114 /** 115 * Finds the appropriate network interface for a given IP address. It 116 * searches the list of network interfaces linearly. A match is found 117 * if the masked IP address of the network interface equals the masked 118 * IP address given to the function. 119 * 120 * @param dest the destination IP address for which to find the route 121 * @return the netif on which to send to reach dest 122 */ 123 struct netif * 124 ip_route(ip_addr_t *dest) 125 { 126 struct netif *netif; 127 128 /* iterate through netifs */ 129 for(netif = netif_list; netif != NULL; netif = netif->next) { 130 /* network mask matches? */ 131 if (netif_is_up(netif)) { 132 if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) { 133 /* return netif on which to forward IP packet */ 134 return netif; 135 } 136 } 137 } 138 if ((netif_default == NULL) || (!netif_is_up(netif_default))) { 139 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 140 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest))); 141 IP_STATS_INC(ip.rterr); 142 snmp_inc_ipoutnoroutes(); 143 return NULL; 144 } 145 /* no matching netif found, use default netif */ 146 return netif_default; 147 } 148 149 #if IP_FORWARD 150 /** 151 * Forwards an IP packet. It finds an appropriate route for the 152 * packet, decrements the TTL value of the packet, adjusts the 153 * checksum and outputs the packet on the appropriate interface. 154 * 155 * @param p the packet to forward (p->payload points to IP header) 156 * @param iphdr the IP header of the input packet 157 * @param inp the netif on which this packet was received 158 */ 159 static void 160 ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp) 161 { 162 struct netif *netif; 163 164 PERF_START; 165 166 /* RFC3927 2.7: do not forward link-local addresses */ 167 if (ip_addr_islinklocal(¤t_iphdr_dest)) { 168 LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 169 ip4_addr1_16(¤t_iphdr_dest), ip4_addr2_16(¤t_iphdr_dest), 170 ip4_addr3_16(¤t_iphdr_dest), ip4_addr4_16(¤t_iphdr_dest))); 171 goto return_noroute; 172 } 173 174 /* Find network interface where to forward this IP packet to. */ 175 netif = ip_route(¤t_iphdr_dest); 176 if (netif == NULL) { 177 LWIP_DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n", 178 ip4_addr1_16(¤t_iphdr_dest), ip4_addr2_16(¤t_iphdr_dest), 179 ip4_addr3_16(¤t_iphdr_dest), ip4_addr4_16(¤t_iphdr_dest))); 180 goto return_noroute; 181 } 182 /* Do not forward packets onto the same network interface on which 183 * they arrived. */ 184 if (netif == inp) { 185 LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not bouncing packets back on incoming interface.\n")); 186 goto return_noroute; 187 } 188 189 /* decrement TTL */ 190 IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1); 191 /* send ICMP if TTL == 0 */ 192 if (IPH_TTL(iphdr) == 0) { 193 snmp_inc_ipinhdrerrors(); 194 #if LWIP_ICMP 195 /* Don't send ICMP messages in response to ICMP messages */ 196 if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) { 197 icmp_time_exceeded(p, ICMP_TE_TTL); 198 } 199 #endif /* LWIP_ICMP */ 200 return; 201 } 202 203 /* Incrementally update the IP checksum. */ 204 if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) { 205 IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1); 206 } else { 207 IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100)); 208 } 209 210 LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 211 ip4_addr1_16(¤t_iphdr_dest), ip4_addr2_16(¤t_iphdr_dest), 212 ip4_addr3_16(¤t_iphdr_dest), ip4_addr4_16(¤t_iphdr_dest))); 213 214 IP_STATS_INC(ip.fw); 215 IP_STATS_INC(ip.xmit); 216 snmp_inc_ipforwdatagrams(); 217 218 PERF_STOP("ip_forward"); 219 /* transmit pbuf on chosen interface */ 220 netif->output(netif, p, ¤t_iphdr_dest); 221 return; 222 return_noroute: 223 snmp_inc_ipoutnoroutes(); 224 } 225 #endif /* IP_FORWARD */ 226 227 /** 228 * This function is called by the network interface device driver when 229 * an IP packet is received. The function does the basic checks of the 230 * IP header such as packet size being at least larger than the header 231 * size etc. If the packet was not destined for us, the packet is 232 * forwarded (using ip_forward). The IP checksum is always checked. 233 * 234 * Finally, the packet is sent to the upper layer protocol input function. 235 * 236 * @param p the received IP packet (p->payload points to IP header) 237 * @param inp the netif on which this packet was received 238 * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't 239 * processed, but currently always returns ERR_OK) 240 */ 241 err_t 242 ip_input(struct pbuf *p, struct netif *inp) 243 { 244 struct ip_hdr *iphdr; 245 struct netif *netif; 246 u16_t iphdr_hlen; 247 u16_t iphdr_len; 248 #if IP_ACCEPT_LINK_LAYER_ADDRESSING 249 int check_ip_src=1; 250 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */ 251 252 IP_STATS_INC(ip.recv); 253 snmp_inc_ipinreceives(); 254 255 /* identify the IP header */ 256 iphdr = (struct ip_hdr *)p->payload; 257 if (IPH_V(iphdr) != 4) { 258 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", IPH_V(iphdr))); 259 ip_debug_print(p); 260 pbuf_free(p); 261 IP_STATS_INC(ip.err); 262 IP_STATS_INC(ip.drop); 263 snmp_inc_ipinhdrerrors(); 264 return ERR_OK; 265 } 266 267 /* obtain IP header length in number of 32-bit words */ 268 iphdr_hlen = IPH_HL(iphdr); 269 /* calculate IP header length in bytes */ 270 iphdr_hlen *= 4; 271 /* obtain ip length in bytes */ 272 iphdr_len = ntohs(IPH_LEN(iphdr)); 273 274 /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */ 275 if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len)) { 276 if (iphdr_hlen > p->len) { 277 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, 278 ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n", 279 iphdr_hlen, p->len)); 280 } 281 if (iphdr_len > p->tot_len) { 282 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, 283 ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n", 284 iphdr_len, p->tot_len)); 285 } 286 /* free (drop) packet pbufs */ 287 pbuf_free(p); 288 IP_STATS_INC(ip.lenerr); 289 IP_STATS_INC(ip.drop); 290 snmp_inc_ipindiscards(); 291 return ERR_OK; 292 } 293 294 /* verify checksum */ 295 #if CHECKSUM_CHECK_IP 296 if (inet_chksum(iphdr, iphdr_hlen) != 0) { 297 298 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, 299 ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen))); 300 ip_debug_print(p); 301 pbuf_free(p); 302 IP_STATS_INC(ip.chkerr); 303 IP_STATS_INC(ip.drop); 304 snmp_inc_ipinhdrerrors(); 305 return ERR_OK; 306 } 307 #endif 308 309 /* Trim pbuf. This should have been done at the netif layer, 310 * but we'll do it anyway just to be sure that its done. */ 311 pbuf_realloc(p, iphdr_len); 312 313 /* copy IP addresses to aligned ip_addr_t */ 314 ip_addr_copy(current_iphdr_dest, iphdr->dest); 315 ip_addr_copy(current_iphdr_src, iphdr->src); 316 317 /* match packet against an interface, i.e. is this packet for us? */ 318 #if LWIP_IGMP 319 if (ip_addr_ismulticast(¤t_iphdr_dest)) { 320 if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ¤t_iphdr_dest))) { 321 netif = inp; 322 } else { 323 netif = NULL; 324 } 325 } else 326 #endif /* LWIP_IGMP */ 327 { 328 /* start trying with inp. if that's not acceptable, start walking the 329 list of configured netifs. 330 'first' is used as a boolean to mark whether we started walking the list */ 331 int first = 1; 332 netif = inp; 333 do { 334 LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest 0x%"X32_F" netif->ip_addr 0x%"X32_F" (0x%"X32_F", 0x%"X32_F", 0x%"X32_F")\n", 335 ip4_addr_get_u32(&iphdr->dest), ip4_addr_get_u32(&netif->ip_addr), 336 ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(&netif->netmask), 337 ip4_addr_get_u32(&netif->ip_addr) & ip4_addr_get_u32(&netif->netmask), 338 ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(&netif->netmask))); 339 340 /* interface is up and configured? */ 341 if ((netif_is_up(netif)) && (!ip_addr_isany(&(netif->ip_addr)))) { 342 /* unicast to this interface address? */ 343 if (ip_addr_cmp(¤t_iphdr_dest, &(netif->ip_addr)) || 344 /* or broadcast on this interface network address? */ 345 ip_addr_isbroadcast(¤t_iphdr_dest, netif)) { 346 LWIP_DEBUGF(IP_DEBUG, ("ip_input: packet accepted on interface %c%c\n", 347 netif->name[0], netif->name[1])); 348 /* break out of for loop */ 349 break; 350 } 351 #if LWIP_AUTOIP 352 /* connections to link-local addresses must persist after changing 353 the netif's address (RFC3927 ch. 1.9) */ 354 if ((netif->autoip != NULL) && 355 ip_addr_cmp(¤t_iphdr_dest, &(netif->autoip->llipaddr))) { 356 LWIP_DEBUGF(IP_DEBUG, ("ip_input: LLA packet accepted on interface %c%c\n", 357 netif->name[0], netif->name[1])); 358 /* break out of for loop */ 359 break; 360 } 361 #endif /* LWIP_AUTOIP */ 362 } 363 if (first) { 364 first = 0; 365 netif = netif_list; 366 } else { 367 netif = netif->next; 368 } 369 if (netif == inp) { 370 netif = netif->next; 371 } 372 } while(netif != NULL); 373 } 374 375 #if IP_ACCEPT_LINK_LAYER_ADDRESSING 376 /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed 377 * using link layer addressing (such as Ethernet MAC) so we must not filter on IP. 378 * According to RFC 1542 section 3.1.1, referred by RFC 2131). 379 * 380 * If you want to accept private broadcast communication while a netif is down, 381 * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.: 382 * 383 * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345)) 384 */ 385 if (netif == NULL) { 386 /* remote port is DHCP server? */ 387 if (IPH_PROTO(iphdr) == IP_PROTO_UDP) { 388 struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen); 389 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: UDP packet to DHCP client port %"U16_F"\n", 390 ntohs(udphdr->dest))); 391 if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) { 392 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: DHCP packet accepted.\n")); 393 netif = inp; 394 check_ip_src = 0; 395 } 396 } 397 } 398 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */ 399 400 /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */ 401 #if IP_ACCEPT_LINK_LAYER_ADDRESSING 402 /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */ 403 if (check_ip_src && !ip_addr_isany(¤t_iphdr_src)) 404 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */ 405 { if ((ip_addr_isbroadcast(¤t_iphdr_src, inp)) || 406 (ip_addr_ismulticast(¤t_iphdr_src))) { 407 /* packet source is not valid */ 408 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip_input: packet source is not valid.\n")); 409 /* free (drop) packet pbufs */ 410 pbuf_free(p); 411 IP_STATS_INC(ip.drop); 412 snmp_inc_ipinaddrerrors(); 413 snmp_inc_ipindiscards(); 414 return ERR_OK; 415 } 416 } 417 418 /* packet not for us? */ 419 if (netif == NULL) { 420 /* packet not for us, route or discard */ 421 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: packet not for us.\n")); 422 #if IP_FORWARD 423 /* non-broadcast packet? */ 424 if (!ip_addr_isbroadcast(¤t_iphdr_dest, inp)) { 425 /* try to forward IP packet on (other) interfaces */ 426 ip_forward(p, iphdr, inp); 427 } else 428 #endif /* IP_FORWARD */ 429 { 430 snmp_inc_ipinaddrerrors(); 431 snmp_inc_ipindiscards(); 432 } 433 pbuf_free(p); 434 return ERR_OK; 435 } 436 /* packet consists of multiple fragments? */ 437 if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) { 438 #if IP_REASSEMBLY /* packet fragment reassembly code present? */ 439 LWIP_DEBUGF(IP_DEBUG, ("IP packet is a fragment (id=0x%04"X16_F" tot_len=%"U16_F" len=%"U16_F" MF=%"U16_F" offset=%"U16_F"), calling ip_reass()\n", 440 ntohs(IPH_ID(iphdr)), p->tot_len, ntohs(IPH_LEN(iphdr)), !!(IPH_OFFSET(iphdr) & PP_HTONS(IP_MF)), (ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8)); 441 /* reassemble the packet*/ 442 p = ip_reass(p); 443 /* packet not fully reassembled yet? */ 444 if (p == NULL) { 445 return ERR_OK; 446 } 447 iphdr = (struct ip_hdr *)p->payload; 448 #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */ 449 pbuf_free(p); 450 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n", 451 ntohs(IPH_OFFSET(iphdr)))); 452 IP_STATS_INC(ip.opterr); 453 IP_STATS_INC(ip.drop); 454 /* unsupported protocol feature */ 455 snmp_inc_ipinunknownprotos(); 456 return ERR_OK; 457 #endif /* IP_REASSEMBLY */ 458 } 459 460 #if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */ 461 462 #if LWIP_IGMP 463 /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */ 464 if((iphdr_hlen > IP_HLEN) && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) { 465 #else 466 if (iphdr_hlen > IP_HLEN) { 467 #endif /* LWIP_IGMP */ 468 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n")); 469 pbuf_free(p); 470 IP_STATS_INC(ip.opterr); 471 IP_STATS_INC(ip.drop); 472 /* unsupported protocol feature */ 473 snmp_inc_ipinunknownprotos(); 474 return ERR_OK; 475 } 476 #endif /* IP_OPTIONS_ALLOWED == 0 */ 477 478 /* send to upper layers */ 479 LWIP_DEBUGF(IP_DEBUG, ("ip_input: \n")); 480 ip_debug_print(p); 481 LWIP_DEBUGF(IP_DEBUG, ("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len)); 482 483 current_netif = inp; 484 current_header = iphdr; 485 486 #if LWIP_RAW 487 /* raw input did not eat the packet? */ 488 if (raw_input(p, inp) == 0) 489 #endif /* LWIP_RAW */ 490 { 491 492 switch (IPH_PROTO(iphdr)) { 493 #if LWIP_UDP 494 case IP_PROTO_UDP: 495 #if LWIP_UDPLITE 496 case IP_PROTO_UDPLITE: 497 #endif /* LWIP_UDPLITE */ 498 snmp_inc_ipindelivers(); 499 udp_input(p, inp); 500 break; 501 #endif /* LWIP_UDP */ 502 #if LWIP_TCP 503 case IP_PROTO_TCP: 504 snmp_inc_ipindelivers(); 505 tcp_input(p, inp); 506 break; 507 #endif /* LWIP_TCP */ 508 #if LWIP_ICMP 509 case IP_PROTO_ICMP: 510 snmp_inc_ipindelivers(); 511 icmp_input(p, inp); 512 break; 513 #endif /* LWIP_ICMP */ 514 #if LWIP_IGMP 515 case IP_PROTO_IGMP: 516 igmp_input(p, inp, ¤t_iphdr_dest); 517 break; 518 #endif /* LWIP_IGMP */ 519 default: 520 #if LWIP_ICMP 521 /* send ICMP destination protocol unreachable unless is was a broadcast */ 522 if (!ip_addr_isbroadcast(¤t_iphdr_dest, inp) && 523 !ip_addr_ismulticast(¤t_iphdr_dest)) { 524 p->payload = iphdr; 525 icmp_dest_unreach(p, ICMP_DUR_PROTO); 526 } 527 #endif /* LWIP_ICMP */ 528 pbuf_free(p); 529 530 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", IPH_PROTO(iphdr))); 531 532 IP_STATS_INC(ip.proterr); 533 IP_STATS_INC(ip.drop); 534 snmp_inc_ipinunknownprotos(); 535 } 536 } 537 538 current_netif = NULL; 539 current_header = NULL; 540 ip_addr_set_any(¤t_iphdr_src); 541 ip_addr_set_any(¤t_iphdr_dest); 542 543 return ERR_OK; 544 } 545 546 /** 547 * Sends an IP packet on a network interface. This function constructs 548 * the IP header and calculates the IP header checksum. If the source 549 * IP address is NULL, the IP address of the outgoing network 550 * interface is filled in as source address. 551 * If the destination IP address is IP_HDRINCL, p is assumed to already 552 * include an IP header and p->payload points to it instead of the data. 553 * 554 * @param p the packet to send (p->payload points to the data, e.g. next 555 protocol header; if dest == IP_HDRINCL, p already includes an IP 556 header and p->payload points to that IP header) 557 * @param src the source IP address to send from (if src == IP_ADDR_ANY, the 558 * IP address of the netif used to send is used as source address) 559 * @param dest the destination IP address to send the packet to 560 * @param ttl the TTL value to be set in the IP header 561 * @param tos the TOS value to be set in the IP header 562 * @param proto the PROTOCOL to be set in the IP header 563 * @param netif the netif on which to send this packet 564 * @return ERR_OK if the packet was sent OK 565 * ERR_BUF if p doesn't have enough space for IP/LINK headers 566 * returns errors returned by netif->output 567 * 568 * @note ip_id: RFC791 "some host may be able to simply use 569 * unique identifiers independent of destination" 570 */ 571 err_t 572 ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, 573 u8_t ttl, u8_t tos, 574 u8_t proto, struct netif *netif) 575 { 576 #if IP_OPTIONS_SEND 577 return ip_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0); 578 } 579 580 /** 581 * Same as ip_output_if() but with the possibility to include IP options: 582 * 583 * @ param ip_options pointer to the IP options, copied into the IP header 584 * @ param optlen length of ip_options 585 */ 586 err_t ip_output_if_opt(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, 587 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options, 588 u16_t optlen) 589 { 590 #endif /* IP_OPTIONS_SEND */ 591 struct ip_hdr *iphdr; 592 ip_addr_t dest_addr; 593 #if CHECKSUM_GEN_IP_INLINE 594 u32_t chk_sum = 0; 595 #endif /* CHECKSUM_GEN_IP_INLINE */ 596 597 /* pbufs passed to IP must have a ref-count of 1 as their payload pointer 598 gets altered as the packet is passed down the stack */ 599 LWIP_ASSERT("p->ref == 1", p->ref == 1); 600 601 snmp_inc_ipoutrequests(); 602 603 /* Should the IP header be generated or is it already included in p? */ 604 if (dest != IP_HDRINCL) { 605 u16_t ip_hlen = IP_HLEN; 606 #if IP_OPTIONS_SEND 607 u16_t optlen_aligned = 0; 608 if (optlen != 0) { 609 #if CHECKSUM_GEN_IP_INLINE 610 int i; 611 #endif /* CHECKSUM_GEN_IP_INLINE */ 612 /* round up to a multiple of 4 */ 613 optlen_aligned = ((optlen + 3) & ~3); 614 ip_hlen += optlen_aligned; 615 /* First write in the IP options */ 616 if (pbuf_header(p, optlen_aligned)) { 617 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output_if_opt: not enough room for IP options in pbuf\n")); 618 IP_STATS_INC(ip.err); 619 snmp_inc_ipoutdiscards(); 620 return ERR_BUF; 621 } 622 MEMCPY(p->payload, ip_options, optlen); 623 if (optlen < optlen_aligned) { 624 /* zero the remaining bytes */ 625 memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen); 626 } 627 #if CHECKSUM_GEN_IP_INLINE 628 for (i = 0; i < optlen_aligned/2; i++) { 629 chk_sum += ((u16_t*)p->payload)[i]; 630 } 631 #endif /* CHECKSUM_GEN_IP_INLINE */ 632 } 633 #endif /* IP_OPTIONS_SEND */ 634 /* generate IP header */ 635 if (pbuf_header(p, IP_HLEN)) { 636 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output: not enough room for IP header in pbuf\n")); 637 638 IP_STATS_INC(ip.err); 639 snmp_inc_ipoutdiscards(); 640 return ERR_BUF; 641 } 642 643 iphdr = (struct ip_hdr *)p->payload; 644 LWIP_ASSERT("check that first pbuf can hold struct ip_hdr", 645 (p->len >= sizeof(struct ip_hdr))); 646 647 IPH_TTL_SET(iphdr, ttl); 648 IPH_PROTO_SET(iphdr, proto); 649 #if CHECKSUM_GEN_IP_INLINE 650 chk_sum += LWIP_MAKE_U16(proto, ttl); 651 #endif /* CHECKSUM_GEN_IP_INLINE */ 652 653 /* dest cannot be NULL here */ 654 ip_addr_copy(iphdr->dest, *dest); 655 #if CHECKSUM_GEN_IP_INLINE 656 chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF; 657 chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16; 658 #endif /* CHECKSUM_GEN_IP_INLINE */ 659 660 IPH_VHLTOS_SET(iphdr, 4, ip_hlen / 4, tos); 661 #if CHECKSUM_GEN_IP_INLINE 662 chk_sum += iphdr->_v_hl_tos; 663 #endif /* CHECKSUM_GEN_IP_INLINE */ 664 IPH_LEN_SET(iphdr, htons(p->tot_len)); 665 #if CHECKSUM_GEN_IP_INLINE 666 chk_sum += iphdr->_len; 667 #endif /* CHECKSUM_GEN_IP_INLINE */ 668 IPH_OFFSET_SET(iphdr, 0); 669 IPH_ID_SET(iphdr, htons(ip_id)); 670 #if CHECKSUM_GEN_IP_INLINE 671 chk_sum += iphdr->_id; 672 #endif /* CHECKSUM_GEN_IP_INLINE */ 673 ++ip_id; 674 675 if (ip_addr_isany(src)) { 676 ip_addr_copy(iphdr->src, netif->ip_addr); 677 } else { 678 /* src cannot be NULL here */ 679 ip_addr_copy(iphdr->src, *src); 680 } 681 682 #if CHECKSUM_GEN_IP_INLINE 683 chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF; 684 chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16; 685 chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF); 686 chk_sum = (chk_sum >> 16) + chk_sum; 687 chk_sum = ~chk_sum; 688 iphdr->_chksum = chk_sum; /* network order */ 689 #else /* CHECKSUM_GEN_IP_INLINE */ 690 IPH_CHKSUM_SET(iphdr, 0); 691 #if CHECKSUM_GEN_IP 692 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen)); 693 #endif 694 #endif /* CHECKSUM_GEN_IP_INLINE */ 695 } else { 696 /* IP header already included in p */ 697 iphdr = (struct ip_hdr *)p->payload; 698 ip_addr_copy(dest_addr, iphdr->dest); 699 dest = &dest_addr; 700 } 701 702 IP_STATS_INC(ip.xmit); 703 704 LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], netif->num)); 705 ip_debug_print(p); 706 707 #if ENABLE_LOOPBACK 708 if (ip_addr_cmp(dest, &netif->ip_addr)) { 709 /* Packet to self, enqueue it for loopback */ 710 LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()")); 711 return netif_loop_output(netif, p, dest); 712 } 713 #if LWIP_IGMP 714 if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) { 715 netif_loop_output(netif, p, dest); 716 } 717 #endif /* LWIP_IGMP */ 718 #endif /* ENABLE_LOOPBACK */ 719 #if IP_FRAG 720 /* don't fragment if interface has mtu set to 0 [loopif] */ 721 if (netif->mtu && (p->tot_len > netif->mtu)) { 722 return ip_frag(p, netif, dest); 723 } 724 #endif /* IP_FRAG */ 725 726 LWIP_DEBUGF(IP_DEBUG, ("netif->output()")); 727 return netif->output(netif, p, dest); 728 } 729 730 /** 731 * Simple interface to ip_output_if. It finds the outgoing network 732 * interface and calls upon ip_output_if to do the actual work. 733 * 734 * @param p the packet to send (p->payload points to the data, e.g. next 735 protocol header; if dest == IP_HDRINCL, p already includes an IP 736 header and p->payload points to that IP header) 737 * @param src the source IP address to send from (if src == IP_ADDR_ANY, the 738 * IP address of the netif used to send is used as source address) 739 * @param dest the destination IP address to send the packet to 740 * @param ttl the TTL value to be set in the IP header 741 * @param tos the TOS value to be set in the IP header 742 * @param proto the PROTOCOL to be set in the IP header 743 * 744 * @return ERR_RTE if no route is found 745 * see ip_output_if() for more return values 746 */ 747 err_t 748 ip_output(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, 749 u8_t ttl, u8_t tos, u8_t proto) 750 { 751 struct netif *netif; 752 753 /* pbufs passed to IP must have a ref-count of 1 as their payload pointer 754 gets altered as the packet is passed down the stack */ 755 LWIP_ASSERT("p->ref == 1", p->ref == 1); 756 757 if ((netif = ip_route(dest)) == NULL) { 758 LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 759 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest))); 760 IP_STATS_INC(ip.rterr); 761 return ERR_RTE; 762 } 763 764 return ip_output_if(p, src, dest, ttl, tos, proto, netif); 765 } 766 767 #if LWIP_NETIF_HWADDRHINT 768 /** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint 769 * before calling ip_output_if. 770 * 771 * @param p the packet to send (p->payload points to the data, e.g. next 772 protocol header; if dest == IP_HDRINCL, p already includes an IP 773 header and p->payload points to that IP header) 774 * @param src the source IP address to send from (if src == IP_ADDR_ANY, the 775 * IP address of the netif used to send is used as source address) 776 * @param dest the destination IP address to send the packet to 777 * @param ttl the TTL value to be set in the IP header 778 * @param tos the TOS value to be set in the IP header 779 * @param proto the PROTOCOL to be set in the IP header 780 * @param addr_hint address hint pointer set to netif->addr_hint before 781 * calling ip_output_if() 782 * 783 * @return ERR_RTE if no route is found 784 * see ip_output_if() for more return values 785 */ 786 err_t 787 ip_output_hinted(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, 788 u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint) 789 { 790 struct netif *netif; 791 err_t err; 792 793 /* pbufs passed to IP must have a ref-count of 1 as their payload pointer 794 gets altered as the packet is passed down the stack */ 795 LWIP_ASSERT("p->ref == 1", p->ref == 1); 796 797 if ((netif = ip_route(dest)) == NULL) { 798 LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 799 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest))); 800 IP_STATS_INC(ip.rterr); 801 return ERR_RTE; 802 } 803 804 netif->addr_hint = addr_hint; 805 err = ip_output_if(p, src, dest, ttl, tos, proto, netif); 806 netif->addr_hint = NULL; 807 808 return err; 809 } 810 #endif /* LWIP_NETIF_HWADDRHINT*/ 811 812 #if IP_DEBUG 813 /* Print an IP header by using LWIP_DEBUGF 814 * @param p an IP packet, p->payload pointing to the IP header 815 */ 816 void 817 ip_debug_print(struct pbuf *p) 818 { 819 struct ip_hdr *iphdr = (struct ip_hdr *)p->payload; 820 u8_t *payload; 821 822 payload = (u8_t *)iphdr + IP_HLEN; 823 824 LWIP_DEBUGF(IP_DEBUG, ("IP header:\n")); 825 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); 826 LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n", 827 IPH_V(iphdr), 828 IPH_HL(iphdr), 829 IPH_TOS(iphdr), 830 ntohs(IPH_LEN(iphdr)))); 831 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); 832 LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n", 833 ntohs(IPH_ID(iphdr)), 834 ntohs(IPH_OFFSET(iphdr)) >> 15 & 1, 835 ntohs(IPH_OFFSET(iphdr)) >> 14 & 1, 836 ntohs(IPH_OFFSET(iphdr)) >> 13 & 1, 837 ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)); 838 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); 839 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n", 840 IPH_TTL(iphdr), 841 IPH_PROTO(iphdr), 842 ntohs(IPH_CHKSUM(iphdr)))); 843 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); 844 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n", 845 ip4_addr1_16(&iphdr->src), 846 ip4_addr2_16(&iphdr->src), 847 ip4_addr3_16(&iphdr->src), 848 ip4_addr4_16(&iphdr->src))); 849 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); 850 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n", 851 ip4_addr1_16(&iphdr->dest), 852 ip4_addr2_16(&iphdr->dest), 853 ip4_addr3_16(&iphdr->dest), 854 ip4_addr4_16(&iphdr->dest))); 855 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); 856 } 857 #endif /* IP_DEBUG */ 858
