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 <[email protected]>
38 *
39 */
40
41 #include "lwip/opt.h"
42
43 #if LWIP_IPV4
44
45 #include "lwip/ip.h"
46 #include "lwip/def.h"
47 #include "lwip/mem.h"
48 #include "lwip/ip4_frag.h"
49 #include "lwip/inet_chksum.h"
50 #include "lwip/netif.h"
51 #include "lwip/icmp.h"
52 #include "lwip/igmp.h"
53 #include "lwip/raw.h"
54 #include "lwip/udp.h"
55 #include "lwip/priv/tcp_priv.h"
56 #include "lwip/autoip.h"
57 #include "lwip/stats.h"
58 #include "lwip/prot/dhcp.h"
59
60 #include <string.h>
61
62 #ifdef LWIP_HOOK_FILENAME
63 #include LWIP_HOOK_FILENAME
64 #endif
65
66 /** Set this to 0 in the rare case of wanting to call an extra function to
67 * generate the IP checksum (in contrast to calculating it on-the-fly). */
68 #ifndef LWIP_INLINE_IP_CHKSUM
69 #if LWIP_CHECKSUM_CTRL_PER_NETIF
70 #define LWIP_INLINE_IP_CHKSUM 0
71 #else /* LWIP_CHECKSUM_CTRL_PER_NETIF */
72 #define LWIP_INLINE_IP_CHKSUM 1
73 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
74 #endif
75
76 #if LWIP_INLINE_IP_CHKSUM && CHECKSUM_GEN_IP
77 #define CHECKSUM_GEN_IP_INLINE 1
78 #else
79 #define CHECKSUM_GEN_IP_INLINE 0
80 #endif
81
82 #if LWIP_DHCP || defined(LWIP_IP_ACCEPT_UDP_PORT)
83 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 1
84
85 /** Some defines for DHCP to let link-layer-addressed packets through while the
86 * netif is down.
87 * To use this in your own application/protocol, define LWIP_IP_ACCEPT_UDP_PORT(port)
88 * to return 1 if the port is accepted and 0 if the port is not accepted.
89 */
90 #if LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT)
91 /* accept DHCP client port and custom port */
92 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (((port) == PP_NTOHS(DHCP_CLIENT_PORT)) \
93 || (LWIP_IP_ACCEPT_UDP_PORT(port)))
94 #elif defined(LWIP_IP_ACCEPT_UDP_PORT) /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
95 /* accept custom port only */
96 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (LWIP_IP_ACCEPT_UDP_PORT(port))
97 #else /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
98 /* accept DHCP client port only */
99 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) ((port) == PP_NTOHS(DHCP_CLIENT_PORT))
100 #endif /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
101
102 #else /* LWIP_DHCP */
103 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 0
104 #endif /* LWIP_DHCP */
105
106 /** The IP header ID of the next outgoing IP packet */
107 static u16_t ip_id;
108
109 #if LWIP_MULTICAST_TX_OPTIONS
110 /** The default netif used for multicast */
111 static struct netif* ip4_default_multicast_netif;
112
113 /**
114 * @ingroup ip4
115 * Set a default netif for IPv4 multicast. */
116 void
ip4_set_default_multicast_netif(struct netif * default_multicast_netif)117 ip4_set_default_multicast_netif(struct netif* default_multicast_netif)
118 {
119 ip4_default_multicast_netif = default_multicast_netif;
120 }
121 #endif /* LWIP_MULTICAST_TX_OPTIONS */
122
123 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
124 /**
125 * Source based IPv4 routing must be fully implemented in
126 * LWIP_HOOK_IP4_ROUTE_SRC(). This function only provides he parameters.
127 */
128 struct netif *
ip4_route_src(const ip4_addr_t * dest,const ip4_addr_t * src)129 ip4_route_src(const ip4_addr_t *dest, const ip4_addr_t *src)
130 {
131 if (src != NULL) {
132 /* when src==NULL, the hook is called from ip4_route(dest) */
133 struct netif *netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, src);
134 if (netif != NULL) {
135 return netif;
136 }
137 }
138 return ip4_route(dest);
139 }
140 #endif /* LWIP_HOOK_IP4_ROUTE_SRC */
141
142 /**
143 * Finds the appropriate network interface for a given IP address. It
144 * searches the list of network interfaces linearly. A match is found
145 * if the masked IP address of the network interface equals the masked
146 * IP address given to the function.
147 *
148 * @param dest the destination IP address for which to find the route
149 * @return the netif on which to send to reach dest
150 */
151 struct netif *
ip4_route(const ip4_addr_t * dest)152 ip4_route(const ip4_addr_t *dest)
153 {
154 struct netif *netif;
155
156 #if LWIP_MULTICAST_TX_OPTIONS
157 /* Use administratively selected interface for multicast by default */
158 if (ip4_addr_ismulticast(dest) && ip4_default_multicast_netif) {
159 return ip4_default_multicast_netif;
160 }
161 #endif /* LWIP_MULTICAST_TX_OPTIONS */
162
163 /* iterate through netifs */
164 for (netif = netif_list; netif != NULL; netif = netif->next) {
165 /* is the netif up, does it have a link and a valid address? */
166 if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
167 /* network mask matches? */
168 if (ip4_addr_netcmp(dest, netif_ip4_addr(netif), netif_ip4_netmask(netif))) {
169 /* return netif on which to forward IP packet */
170 return netif;
171 }
172 /* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */
173 if (((netif->flags & NETIF_FLAG_BROADCAST) == 0) && ip4_addr_cmp(dest, netif_ip4_gw(netif))) {
174 /* return netif on which to forward IP packet */
175 return netif;
176 }
177 }
178 }
179
180 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
181 /* loopif is disabled, looopback traffic is passed through any netif */
182 if (ip4_addr_isloopback(dest)) {
183 /* don't check for link on loopback traffic */
184 if (netif_default != NULL && netif_is_up(netif_default)) {
185 return netif_default;
186 }
187 /* default netif is not up, just use any netif for loopback traffic */
188 for (netif = netif_list; netif != NULL; netif = netif->next) {
189 if (netif_is_up(netif)) {
190 return netif;
191 }
192 }
193 return NULL;
194 }
195 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
196
197 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
198 netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, NULL);
199 if (netif != NULL) {
200 return netif;
201 }
202 #elif defined(LWIP_HOOK_IP4_ROUTE)
203 netif = LWIP_HOOK_IP4_ROUTE(dest);
204 if (netif != NULL) {
205 return netif;
206 }
207 #endif
208
209 if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default) ||
210 ip4_addr_isany_val(*netif_ip4_addr(netif_default))) {
211 /* No matching netif found and default netif is not usable.
212 If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
213 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
214 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
215 IP_STATS_INC(ip.rterr);
216 MIB2_STATS_INC(mib2.ipoutnoroutes);
217 return NULL;
218 }
219
220 return netif_default;
221 }
222
223 #if IP_FORWARD
224 /**
225 * Determine whether an IP address is in a reserved set of addresses
226 * that may not be forwarded, or whether datagrams to that destination
227 * may be forwarded.
228 * @param p the packet to forward
229 * @return 1: can forward 0: discard
230 */
231 static int
ip4_canforward(struct pbuf * p)232 ip4_canforward(struct pbuf *p)
233 {
234 u32_t addr = lwip_htonl(ip4_addr_get_u32(ip4_current_dest_addr()));
235
236 if (p->flags & PBUF_FLAG_LLBCAST) {
237 /* don't route link-layer broadcasts */
238 return 0;
239 }
240 if ((p->flags & PBUF_FLAG_LLMCAST) && !IP_MULTICAST(addr)) {
241 /* don't route link-layer multicasts unless the destination address is an IP
242 multicast address */
243 return 0;
244 }
245 if (IP_EXPERIMENTAL(addr)) {
246 return 0;
247 }
248 if (IP_CLASSA(addr)) {
249 u32_t net = addr & IP_CLASSA_NET;
250 if ((net == 0) || (net == ((u32_t)IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
251 /* don't route loopback packets */
252 return 0;
253 }
254 }
255 return 1;
256 }
257
258 /**
259 * Forwards an IP packet. It finds an appropriate route for the
260 * packet, decrements the TTL value of the packet, adjusts the
261 * checksum and outputs the packet on the appropriate interface.
262 *
263 * @param p the packet to forward (p->payload points to IP header)
264 * @param iphdr the IP header of the input packet
265 * @param inp the netif on which this packet was received
266 */
267 static void
ip4_forward(struct pbuf * p,struct ip_hdr * iphdr,struct netif * inp)268 ip4_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
269 {
270 struct netif *netif;
271
272 PERF_START;
273 LWIP_UNUSED_ARG(inp);
274
275 if (!ip4_canforward(p)) {
276 goto return_noroute;
277 }
278
279 /* RFC3927 2.7: do not forward link-local addresses */
280 if (ip4_addr_islinklocal(ip4_current_dest_addr())) {
281 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
282 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
283 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
284 goto return_noroute;
285 }
286
287 /* Find network interface where to forward this IP packet to. */
288 netif = ip4_route_src(ip4_current_dest_addr(), ip4_current_src_addr());
289 if (netif == NULL) {
290 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
291 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
292 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
293 /* @todo: send ICMP_DUR_NET? */
294 goto return_noroute;
295 }
296 #if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
297 /* Do not forward packets onto the same network interface on which
298 * they arrived. */
299 if (netif == inp) {
300 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not bouncing packets back on incoming interface.\n"));
301 goto return_noroute;
302 }
303 #endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
304
305 /* decrement TTL */
306 IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
307 /* send ICMP if TTL == 0 */
308 if (IPH_TTL(iphdr) == 0) {
309 MIB2_STATS_INC(mib2.ipinhdrerrors);
310 #if LWIP_ICMP
311 /* Don't send ICMP messages in response to ICMP messages */
312 if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
313 icmp_time_exceeded(p, ICMP_TE_TTL);
314 }
315 #endif /* LWIP_ICMP */
316 return;
317 }
318
319 /* Incrementally update the IP checksum. */
320 if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
321 IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1);
322 } else {
323 IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100));
324 }
325
326 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
327 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
328 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
329
330 IP_STATS_INC(ip.fw);
331 MIB2_STATS_INC(mib2.ipforwdatagrams);
332 IP_STATS_INC(ip.xmit);
333
334 PERF_STOP("ip4_forward");
335 /* don't fragment if interface has mtu set to 0 [loopif] */
336 if (netif->mtu && (p->tot_len > netif->mtu)) {
337 if ((IPH_OFFSET(iphdr) & PP_NTOHS(IP_DF)) == 0) {
338 #if IP_FRAG
339 ip4_frag(p, netif, ip4_current_dest_addr());
340 #else /* IP_FRAG */
341 /* @todo: send ICMP Destination Unreachable code 13 "Communication administratively prohibited"? */
342 #endif /* IP_FRAG */
343 } else {
344 #if LWIP_ICMP
345 /* send ICMP Destination Unreachable code 4: "Fragmentation Needed and DF Set" */
346 icmp_dest_unreach(p, ICMP_DUR_FRAG);
347 #endif /* LWIP_ICMP */
348 }
349 return;
350 }
351 /* transmit pbuf on chosen interface */
352 netif->output(netif, p, ip4_current_dest_addr());
353 return;
354 return_noroute:
355 MIB2_STATS_INC(mib2.ipoutnoroutes);
356 }
357 #endif /* IP_FORWARD */
358
359 /**
360 * This function is called by the network interface device driver when
361 * an IP packet is received. The function does the basic checks of the
362 * IP header such as packet size being at least larger than the header
363 * size etc. If the packet was not destined for us, the packet is
364 * forwarded (using ip_forward). The IP checksum is always checked.
365 *
366 * Finally, the packet is sent to the upper layer protocol input function.
367 *
368 * @param p the received IP packet (p->payload points to IP header)
369 * @param inp the netif on which this packet was received
370 * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
371 * processed, but currently always returns ERR_OK)
372 */
373 err_t
ip4_input(struct pbuf * p,struct netif * inp)374 ip4_input(struct pbuf *p, struct netif *inp)
375 {
376 struct ip_hdr *iphdr;
377 struct netif *netif;
378 u16_t iphdr_hlen;
379 u16_t iphdr_len;
380 #if IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP
381 int check_ip_src = 1;
382 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP */
383
384 IP_STATS_INC(ip.recv);
385 MIB2_STATS_INC(mib2.ipinreceives);
386
387 /* identify the IP header */
388 iphdr = (struct ip_hdr *)p->payload;
389 if (IPH_V(iphdr) != 4) {
390 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", (u16_t)IPH_V(iphdr)));
391 ip4_debug_print(p);
392 pbuf_free(p);
393 IP_STATS_INC(ip.err);
394 IP_STATS_INC(ip.drop);
395 MIB2_STATS_INC(mib2.ipinhdrerrors);
396 return ERR_OK;
397 }
398
399 #ifdef LWIP_HOOK_IP4_INPUT
400 if (LWIP_HOOK_IP4_INPUT(p, inp)) {
401 /* the packet has been eaten */
402 return ERR_OK;
403 }
404 #endif
405
406 /* obtain IP header length in number of 32-bit words */
407 iphdr_hlen = IPH_HL(iphdr);
408 /* calculate IP header length in bytes */
409 iphdr_hlen *= 4;
410 /* obtain ip length in bytes */
411 iphdr_len = lwip_ntohs(IPH_LEN(iphdr));
412
413 /* Trim pbuf. This is especially required for packets < 60 bytes. */
414 if (iphdr_len < p->tot_len) {
415 pbuf_realloc(p, iphdr_len);
416 }
417
418 /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
419 if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len) || (iphdr_hlen < IP_HLEN)) {
420 if (iphdr_hlen < IP_HLEN) {
421 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
422 ("ip4_input: short IP header (%"U16_F" bytes) received, IP packet dropped\n", iphdr_hlen));
423 }
424 if (iphdr_hlen > p->len) {
425 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
426 ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
427 iphdr_hlen, p->len));
428 }
429 if (iphdr_len > p->tot_len) {
430 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
431 ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
432 iphdr_len, p->tot_len));
433 }
434 /* free (drop) packet pbufs */
435 pbuf_free(p);
436 IP_STATS_INC(ip.lenerr);
437 IP_STATS_INC(ip.drop);
438 MIB2_STATS_INC(mib2.ipindiscards);
439 return ERR_OK;
440 }
441
442 /* verify checksum */
443 #if CHECKSUM_CHECK_IP
444 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_IP) {
445 if (inet_chksum(iphdr, iphdr_hlen) != 0) {
446
447 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
448 ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
449 ip4_debug_print(p);
450 pbuf_free(p);
451 IP_STATS_INC(ip.chkerr);
452 IP_STATS_INC(ip.drop);
453 MIB2_STATS_INC(mib2.ipinhdrerrors);
454 return ERR_OK;
455 }
456 }
457 #endif
458
459 /* copy IP addresses to aligned ip_addr_t */
460 ip_addr_copy_from_ip4(ip_data.current_iphdr_dest, iphdr->dest);
461 ip_addr_copy_from_ip4(ip_data.current_iphdr_src, iphdr->src);
462
463 /* match packet against an interface, i.e. is this packet for us? */
464 if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
465 #if LWIP_IGMP
466 if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ip4_current_dest_addr()))) {
467 /* IGMP snooping switches need 0.0.0.0 to be allowed as source address (RFC 4541) */
468 ip4_addr_t allsystems;
469 IP4_ADDR(&allsystems, 224, 0, 0, 1);
470 if (ip4_addr_cmp(ip4_current_dest_addr(), &allsystems) &&
471 ip4_addr_isany(ip4_current_src_addr())) {
472 check_ip_src = 0;
473 }
474 netif = inp;
475 } else {
476 netif = NULL;
477 }
478 #else /* LWIP_IGMP */
479 if ((netif_is_up(inp)) && (!ip4_addr_isany_val(*netif_ip4_addr(inp)))) {
480 netif = inp;
481 } else {
482 netif = NULL;
483 }
484 #endif /* LWIP_IGMP */
485 } else {
486 /* start trying with inp. if that's not acceptable, start walking the
487 list of configured netifs.
488 'first' is used as a boolean to mark whether we started walking the list */
489 int first = 1;
490 netif = inp;
491 do {
492 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",
493 ip4_addr_get_u32(&iphdr->dest), ip4_addr_get_u32(netif_ip4_addr(netif)),
494 ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
495 ip4_addr_get_u32(netif_ip4_addr(netif)) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
496 ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(netif_ip4_netmask(netif))));
497
498 /* interface is up and configured? */
499 if ((netif_is_up(netif)) && (!ip4_addr_isany_val(*netif_ip4_addr(netif)))) {
500 /* unicast to this interface address? */
501 if (ip4_addr_cmp(ip4_current_dest_addr(), netif_ip4_addr(netif)) ||
502 /* or broadcast on this interface network address? */
503 ip4_addr_isbroadcast(ip4_current_dest_addr(), netif)
504 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
505 || (ip4_addr_get_u32(ip4_current_dest_addr()) == PP_HTONL(IPADDR_LOOPBACK))
506 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
507 ) {
508 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: packet accepted on interface %c%c\n",
509 netif->name[0], netif->name[1]));
510 /* break out of for loop */
511 break;
512 }
513 #if LWIP_AUTOIP
514 /* connections to link-local addresses must persist after changing
515 the netif's address (RFC3927 ch. 1.9) */
516 if (autoip_accept_packet(netif, ip4_current_dest_addr())) {
517 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: LLA packet accepted on interface %c%c\n",
518 netif->name[0], netif->name[1]));
519 /* break out of for loop */
520 break;
521 }
522 #endif /* LWIP_AUTOIP */
523 }
524 if (first) {
525 #if !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF
526 /* Packets sent to the loopback address must not be accepted on an
527 * interface that does not have the loopback address assigned to it,
528 * unless a non-loopback interface is used for loopback traffic. */
529 if (ip4_addr_isloopback(ip4_current_dest_addr())) {
530 netif = NULL;
531 break;
532 }
533 #endif /* !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF */
534 first = 0;
535 netif = netif_list;
536 } else {
537 netif = netif->next;
538 }
539 if (netif == inp) {
540 netif = netif->next;
541 }
542 } while (netif != NULL);
543 }
544
545 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
546 /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
547 * using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
548 * According to RFC 1542 section 3.1.1, referred by RFC 2131).
549 *
550 * If you want to accept private broadcast communication while a netif is down,
551 * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
552 *
553 * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
554 */
555 if (netif == NULL) {
556 /* remote port is DHCP server? */
557 if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
558 struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen);
559 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: UDP packet to DHCP client port %"U16_F"\n",
560 lwip_ntohs(udphdr->dest)));
561 if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
562 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: DHCP packet accepted.\n"));
563 netif = inp;
564 check_ip_src = 0;
565 }
566 }
567 }
568 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
569
570 /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
571 #if LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING
572 if (check_ip_src
573 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
574 /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
575 && !ip4_addr_isany_val(*ip4_current_src_addr())
576 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
577 )
578 #endif /* LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING */
579 {
580 if ((ip4_addr_isbroadcast(ip4_current_src_addr(), inp)) ||
581 (ip4_addr_ismulticast(ip4_current_src_addr()))) {
582 /* packet source is not valid */
583 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip4_input: packet source is not valid.\n"));
584 /* free (drop) packet pbufs */
585 pbuf_free(p);
586 IP_STATS_INC(ip.drop);
587 MIB2_STATS_INC(mib2.ipinaddrerrors);
588 MIB2_STATS_INC(mib2.ipindiscards);
589 return ERR_OK;
590 }
591 }
592
593 /* packet not for us? */
594 if (netif == NULL) {
595 /* packet not for us, route or discard */
596 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: packet not for us.\n"));
597 #if IP_FORWARD
598 /* non-broadcast packet? */
599 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), inp)) {
600 /* try to forward IP packet on (other) interfaces */
601 ip4_forward(p, iphdr, inp);
602 } else
603 #endif /* IP_FORWARD */
604 {
605 IP_STATS_INC(ip.drop);
606 MIB2_STATS_INC(mib2.ipinaddrerrors);
607 MIB2_STATS_INC(mib2.ipindiscards);
608 }
609 pbuf_free(p);
610 return ERR_OK;
611 }
612 /* packet consists of multiple fragments? */
613 if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) {
614 #if IP_REASSEMBLY /* packet fragment reassembly code present? */
615 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 ip4_reass()\n",
616 lwip_ntohs(IPH_ID(iphdr)), p->tot_len, lwip_ntohs(IPH_LEN(iphdr)), (u16_t)!!(IPH_OFFSET(iphdr) & PP_HTONS(IP_MF)), (u16_t)((lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8)));
617 /* reassemble the packet*/
618 p = ip4_reass(p);
619 /* packet not fully reassembled yet? */
620 if (p == NULL) {
621 return ERR_OK;
622 }
623 iphdr = (struct ip_hdr *)p->payload;
624 #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
625 pbuf_free(p);
626 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
627 lwip_ntohs(IPH_OFFSET(iphdr))));
628 IP_STATS_INC(ip.opterr);
629 IP_STATS_INC(ip.drop);
630 /* unsupported protocol feature */
631 MIB2_STATS_INC(mib2.ipinunknownprotos);
632 return ERR_OK;
633 #endif /* IP_REASSEMBLY */
634 }
635
636 #if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
637
638 #if LWIP_IGMP
639 /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
640 if ((iphdr_hlen > IP_HLEN) && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
641 #else
642 if (iphdr_hlen > IP_HLEN) {
643 #endif /* LWIP_IGMP */
644 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
645 pbuf_free(p);
646 IP_STATS_INC(ip.opterr);
647 IP_STATS_INC(ip.drop);
648 /* unsupported protocol feature */
649 MIB2_STATS_INC(mib2.ipinunknownprotos);
650 return ERR_OK;
651 }
652 #endif /* IP_OPTIONS_ALLOWED == 0 */
653
654 /* send to upper layers */
655 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: \n"));
656 ip4_debug_print(p);
657 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
658
659 ip_data.current_netif = netif;
660 ip_data.current_input_netif = inp;
661 ip_data.current_ip4_header = iphdr;
662 ip_data.current_ip_header_tot_len = IPH_HL(iphdr) * 4;
663
664 #if LWIP_RAW
665 /* raw input did not eat the packet? */
666 if (raw_input(p, inp) == 0)
667 #endif /* LWIP_RAW */
668 {
669 pbuf_header(p, -(s16_t)iphdr_hlen); /* Move to payload, no check necessary. */
670
671 switch (IPH_PROTO(iphdr)) {
672 #if LWIP_UDP
673 case IP_PROTO_UDP:
674 #if LWIP_UDPLITE
675 case IP_PROTO_UDPLITE:
676 #endif /* LWIP_UDPLITE */
677 MIB2_STATS_INC(mib2.ipindelivers);
678 udp_input(p, inp);
679 break;
680 #endif /* LWIP_UDP */
681 #if LWIP_TCP
682 case IP_PROTO_TCP:
683 MIB2_STATS_INC(mib2.ipindelivers);
684 tcp_input(p, inp);
685 break;
686 #endif /* LWIP_TCP */
687 #if LWIP_ICMP
688 case IP_PROTO_ICMP:
689 MIB2_STATS_INC(mib2.ipindelivers);
690 icmp_input(p, inp);
691 break;
692 #endif /* LWIP_ICMP */
693 #if LWIP_IGMP
694 case IP_PROTO_IGMP:
695 igmp_input(p, inp, ip4_current_dest_addr());
696 break;
697 #endif /* LWIP_IGMP */
698 default:
699 #if LWIP_ICMP
700 /* send ICMP destination protocol unreachable unless is was a broadcast */
701 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), netif) &&
702 !ip4_addr_ismulticast(ip4_current_dest_addr())) {
703 pbuf_header_force(p, iphdr_hlen); /* Move to ip header, no check necessary. */
704 p->payload = iphdr;
705 icmp_dest_unreach(p, ICMP_DUR_PROTO);
706 }
707 #endif /* LWIP_ICMP */
708 pbuf_free(p);
709
710 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", (u16_t)IPH_PROTO(iphdr)));
711
712 IP_STATS_INC(ip.proterr);
713 IP_STATS_INC(ip.drop);
714 MIB2_STATS_INC(mib2.ipinunknownprotos);
715 }
716 }
717
718 /* @todo: this is not really necessary... */
719 ip_data.current_netif = NULL;
720 ip_data.current_input_netif = NULL;
721 ip_data.current_ip4_header = NULL;
722 ip_data.current_ip_header_tot_len = 0;
723 ip4_addr_set_any(ip4_current_src_addr());
724 ip4_addr_set_any(ip4_current_dest_addr());
725
726 return ERR_OK;
727 }
728
729 /**
730 * Sends an IP packet on a network interface. This function constructs
731 * the IP header and calculates the IP header checksum. If the source
732 * IP address is NULL, the IP address of the outgoing network
733 * interface is filled in as source address.
734 * If the destination IP address is LWIP_IP_HDRINCL, p is assumed to already
735 * include an IP header and p->payload points to it instead of the data.
736 *
737 * @param p the packet to send (p->payload points to the data, e.g. next
738 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
739 IP header and p->payload points to that IP header)
740 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
741 * IP address of the netif used to send is used as source address)
742 * @param dest the destination IP address to send the packet to
743 * @param ttl the TTL value to be set in the IP header
744 * @param tos the TOS value to be set in the IP header
745 * @param proto the PROTOCOL to be set in the IP header
746 * @param netif the netif on which to send this packet
747 * @return ERR_OK if the packet was sent OK
748 * ERR_BUF if p doesn't have enough space for IP/LINK headers
749 * returns errors returned by netif->output
750 *
751 * @note ip_id: RFC791 "some host may be able to simply use
752 * unique identifiers independent of destination"
753 */
754 err_t
755 ip4_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
756 u8_t ttl, u8_t tos,
757 u8_t proto, struct netif *netif)
758 {
759 #if IP_OPTIONS_SEND
760 return ip4_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
761 }
762
763 /**
764 * Same as ip_output_if() but with the possibility to include IP options:
765 *
766 * @ param ip_options pointer to the IP options, copied into the IP header
767 * @ param optlen length of ip_options
768 */
769 err_t
770 ip4_output_if_opt(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
771 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
772 u16_t optlen)
773 {
774 #endif /* IP_OPTIONS_SEND */
775 const ip4_addr_t *src_used = src;
776 if (dest != LWIP_IP_HDRINCL) {
777 if (ip4_addr_isany(src)) {
778 src_used = netif_ip4_addr(netif);
779 }
780 }
781
782 #if IP_OPTIONS_SEND
783 return ip4_output_if_opt_src(p, src_used, dest, ttl, tos, proto, netif,
784 ip_options, optlen);
785 #else /* IP_OPTIONS_SEND */
786 return ip4_output_if_src(p, src_used, dest, ttl, tos, proto, netif);
787 #endif /* IP_OPTIONS_SEND */
788 }
789
790 /**
791 * Same as ip_output_if() but 'src' address is not replaced by netif address
792 * when it is 'any'.
793 */
794 err_t
795 ip4_output_if_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
796 u8_t ttl, u8_t tos,
797 u8_t proto, struct netif *netif)
798 {
799 #if IP_OPTIONS_SEND
800 return ip4_output_if_opt_src(p, src, dest, ttl, tos, proto, netif, NULL, 0);
801 }
802
803 /**
804 * Same as ip_output_if_opt() but 'src' address is not replaced by netif address
805 * when it is 'any'.
806 */
807 err_t
808 ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
809 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
810 u16_t optlen)
811 {
812 #endif /* IP_OPTIONS_SEND */
813 struct ip_hdr *iphdr;
814 ip4_addr_t dest_addr;
815 #if CHECKSUM_GEN_IP_INLINE
816 u32_t chk_sum = 0;
817 #endif /* CHECKSUM_GEN_IP_INLINE */
818
819 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
820
821 MIB2_STATS_INC(mib2.ipoutrequests);
822
823 /* Should the IP header be generated or is it already included in p? */
824 if (dest != LWIP_IP_HDRINCL) {
825 u16_t ip_hlen = IP_HLEN;
826 #if IP_OPTIONS_SEND
827 u16_t optlen_aligned = 0;
828 if (optlen != 0) {
829 #if CHECKSUM_GEN_IP_INLINE
830 int i;
831 #endif /* CHECKSUM_GEN_IP_INLINE */
832 /* round up to a multiple of 4 */
833 optlen_aligned = ((optlen + 3) & ~3);
834 ip_hlen += optlen_aligned;
835 /* First write in the IP options */
836 if (pbuf_header(p, optlen_aligned)) {
837 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: not enough room for IP options in pbuf\n"));
838 IP_STATS_INC(ip.err);
839 MIB2_STATS_INC(mib2.ipoutdiscards);
840 return ERR_BUF;
841 }
842 MEMCPY(p->payload, ip_options, optlen);
843 if (optlen < optlen_aligned) {
844 /* zero the remaining bytes */
845 memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen);
846 }
847 #if CHECKSUM_GEN_IP_INLINE
848 for (i = 0; i < optlen_aligned/2; i++) {
849 chk_sum += ((u16_t*)p->payload)[i];
850 }
851 #endif /* CHECKSUM_GEN_IP_INLINE */
852 }
853 #endif /* IP_OPTIONS_SEND */
854 /* generate IP header */
855 if (pbuf_header(p, IP_HLEN)) {
856 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: not enough room for IP header in pbuf\n"));
857
858 IP_STATS_INC(ip.err);
859 MIB2_STATS_INC(mib2.ipoutdiscards);
860 return ERR_BUF;
861 }
862
863 iphdr = (struct ip_hdr *)p->payload;
864 LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
865 (p->len >= sizeof(struct ip_hdr)));
866
867 IPH_TTL_SET(iphdr, ttl);
868 IPH_PROTO_SET(iphdr, proto);
869 #if CHECKSUM_GEN_IP_INLINE
870 chk_sum += PP_NTOHS(proto | (ttl << 8));
871 #endif /* CHECKSUM_GEN_IP_INLINE */
872
873 /* dest cannot be NULL here */
874 ip4_addr_copy(iphdr->dest, *dest);
875 #if CHECKSUM_GEN_IP_INLINE
876 chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
877 chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
878 #endif /* CHECKSUM_GEN_IP_INLINE */
879
880 IPH_VHL_SET(iphdr, 4, ip_hlen / 4);
881 IPH_TOS_SET(iphdr, tos);
882 #if CHECKSUM_GEN_IP_INLINE
883 chk_sum += PP_NTOHS(tos | (iphdr->_v_hl << 8));
884 #endif /* CHECKSUM_GEN_IP_INLINE */
885 IPH_LEN_SET(iphdr, lwip_htons(p->tot_len));
886 #if CHECKSUM_GEN_IP_INLINE
887 chk_sum += iphdr->_len;
888 #endif /* CHECKSUM_GEN_IP_INLINE */
889 IPH_OFFSET_SET(iphdr, 0);
890 IPH_ID_SET(iphdr, lwip_htons(ip_id));
891 #if CHECKSUM_GEN_IP_INLINE
892 chk_sum += iphdr->_id;
893 #endif /* CHECKSUM_GEN_IP_INLINE */
894 ++ip_id;
895
896 if (src == NULL) {
897 ip4_addr_copy(iphdr->src, *IP4_ADDR_ANY4);
898 } else {
899 /* src cannot be NULL here */
900 ip4_addr_copy(iphdr->src, *src);
901 }
902
903 #if CHECKSUM_GEN_IP_INLINE
904 chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
905 chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
906 chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
907 chk_sum = (chk_sum >> 16) + chk_sum;
908 chk_sum = ~chk_sum;
909 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
910 iphdr->_chksum = (u16_t)chk_sum; /* network order */
911 }
912 #if LWIP_CHECKSUM_CTRL_PER_NETIF
913 else {
914 IPH_CHKSUM_SET(iphdr, 0);
915 }
916 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF*/
917 #else /* CHECKSUM_GEN_IP_INLINE */
918 IPH_CHKSUM_SET(iphdr, 0);
919 #if CHECKSUM_GEN_IP
920 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
921 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
922 }
923 #endif /* CHECKSUM_GEN_IP */
924 #endif /* CHECKSUM_GEN_IP_INLINE */
925 } else {
926 /* IP header already included in p */
927 iphdr = (struct ip_hdr *)p->payload;
928 ip4_addr_copy(dest_addr, iphdr->dest);
929 dest = &dest_addr;
930 }
931
932 IP_STATS_INC(ip.xmit);
933
934 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
935 ip4_debug_print(p);
936
937 #if ENABLE_LOOPBACK
938 if (ip4_addr_cmp(dest, netif_ip4_addr(netif))
939 #if !LWIP_HAVE_LOOPIF
940 || ip4_addr_isloopback(dest)
941 #endif /* !LWIP_HAVE_LOOPIF */
942 ) {
943 /* Packet to self, enqueue it for loopback */
944 LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
945 return netif_loop_output(netif, p);
946 }
947 #if LWIP_MULTICAST_TX_OPTIONS
948 if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
949 netif_loop_output(netif, p);
950 }
951 #endif /* LWIP_MULTICAST_TX_OPTIONS */
952 #endif /* ENABLE_LOOPBACK */
953 #if IP_FRAG
954 /* don't fragment if interface has mtu set to 0 [loopif] */
955 if (netif->mtu && (p->tot_len > netif->mtu)) {
956 return ip4_frag(p, netif, dest);
957 }
958 #endif /* IP_FRAG */
959
960 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));
961 return netif->output(netif, p, dest);
962 }
963
964 /**
965 * Simple interface to ip_output_if. It finds the outgoing network
966 * interface and calls upon ip_output_if to do the actual work.
967 *
968 * @param p the packet to send (p->payload points to the data, e.g. next
969 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
970 IP header and p->payload points to that IP header)
971 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
972 * IP address of the netif used to send is used as source address)
973 * @param dest the destination IP address to send the packet to
974 * @param ttl the TTL value to be set in the IP header
975 * @param tos the TOS value to be set in the IP header
976 * @param proto the PROTOCOL to be set in the IP header
977 *
978 * @return ERR_RTE if no route is found
979 * see ip_output_if() for more return values
980 */
981 err_t
982 ip4_output(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
983 u8_t ttl, u8_t tos, u8_t proto)
984 {
985 struct netif *netif;
986
987 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
988
989 if ((netif = ip4_route_src(dest, src)) == NULL) {
990 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
991 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
992 IP_STATS_INC(ip.rterr);
993 return ERR_RTE;
994 }
995
996 return ip4_output_if(p, src, dest, ttl, tos, proto, netif);
997 }
998
999 #if LWIP_NETIF_HWADDRHINT
1000 /** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
1001 * before calling ip_output_if.
1002 *
1003 * @param p the packet to send (p->payload points to the data, e.g. next
1004 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
1005 IP header and p->payload points to that IP header)
1006 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
1007 * IP address of the netif used to send is used as source address)
1008 * @param dest the destination IP address to send the packet to
1009 * @param ttl the TTL value to be set in the IP header
1010 * @param tos the TOS value to be set in the IP header
1011 * @param proto the PROTOCOL to be set in the IP header
1012 * @param addr_hint address hint pointer set to netif->addr_hint before
1013 * calling ip_output_if()
1014 *
1015 * @return ERR_RTE if no route is found
1016 * see ip_output_if() for more return values
1017 */
1018 err_t
1019 ip4_output_hinted(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
1020 u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
1021 {
1022 struct netif *netif;
1023 err_t err;
1024
1025 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
1026
1027 if ((netif = ip4_route_src(dest, src)) == NULL) {
1028 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1029 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
1030 IP_STATS_INC(ip.rterr);
1031 return ERR_RTE;
1032 }
1033
1034 NETIF_SET_HWADDRHINT(netif, addr_hint);
1035 err = ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1036 NETIF_SET_HWADDRHINT(netif, NULL);
1037
1038 return err;
1039 }
1040 #endif /* LWIP_NETIF_HWADDRHINT*/
1041
1042 #if IP_DEBUG
1043 /* Print an IP header by using LWIP_DEBUGF
1044 * @param p an IP packet, p->payload pointing to the IP header
1045 */
1046 void
1047 ip4_debug_print(struct pbuf *p)
1048 {
1049 struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
1050
1051 LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
1052 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1053 LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n",
1054 (u16_t)IPH_V(iphdr),
1055 (u16_t)IPH_HL(iphdr),
1056 (u16_t)IPH_TOS(iphdr),
1057 lwip_ntohs(IPH_LEN(iphdr))));
1058 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1059 LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n",
1060 lwip_ntohs(IPH_ID(iphdr)),
1061 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 15 & 1),
1062 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 14 & 1),
1063 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 13 & 1),
1064 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)));
1065 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1066 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n",
1067 (u16_t)IPH_TTL(iphdr),
1068 (u16_t)IPH_PROTO(iphdr),
1069 lwip_ntohs(IPH_CHKSUM(iphdr))));
1070 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1071 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n",
1072 ip4_addr1_16(&iphdr->src),
1073 ip4_addr2_16(&iphdr->src),
1074 ip4_addr3_16(&iphdr->src),
1075 ip4_addr4_16(&iphdr->src)));
1076 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1077 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n",
1078 ip4_addr1_16(&iphdr->dest),
1079 ip4_addr2_16(&iphdr->dest),
1080 ip4_addr3_16(&iphdr->dest),
1081 ip4_addr4_16(&iphdr->dest)));
1082 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1083 }
1084 #endif /* IP_DEBUG */
1085
1086 #endif /* LWIP_IPV4 */
1087