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@sics.se>
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 /** Set this to 0 in the rare case of wanting to call an extra function to
63 * generate the IP checksum (in contrast to calculating it on-the-fly). */
64 #ifndef LWIP_INLINE_IP_CHKSUM
65 #if LWIP_CHECKSUM_CTRL_PER_NETIF
66 #define LWIP_INLINE_IP_CHKSUM 0
67 #else /* LWIP_CHECKSUM_CTRL_PER_NETIF */
68 #define LWIP_INLINE_IP_CHKSUM 1
69 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
70 #endif
71
72 #if LWIP_INLINE_IP_CHKSUM && CHECKSUM_GEN_IP
73 #define CHECKSUM_GEN_IP_INLINE 1
74 #else
75 #define CHECKSUM_GEN_IP_INLINE 0
76 #endif
77
78 #if LWIP_DHCP || defined(LWIP_IP_ACCEPT_UDP_PORT)
79 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 1
80
81 /** Some defines for DHCP to let link-layer-addressed packets through while the
82 * netif is down.
83 * To use this in your own application/protocol, define LWIP_IP_ACCEPT_UDP_PORT(port)
84 * to return 1 if the port is accepted and 0 if the port is not accepted.
85 */
86 #if LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT)
87 /* accept DHCP client port and custom port */
88 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (((port) == PP_NTOHS(DHCP_CLIENT_PORT)) \
89 || (LWIP_IP_ACCEPT_UDP_PORT(port)))
90 #elif defined(LWIP_IP_ACCEPT_UDP_PORT) /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
91 /* accept custom port only */
92 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (LWIP_IP_ACCEPT_UDP_PORT(port))
93 #else /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
94 /* accept DHCP client port only */
95 #define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) ((port) == PP_NTOHS(DHCP_CLIENT_PORT))
96 #endif /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
97
98 #else /* LWIP_DHCP */
99 #define IP_ACCEPT_LINK_LAYER_ADDRESSING 0
100 #endif /* LWIP_DHCP */
101
102 /** The IP header ID of the next outgoing IP packet */
103 static u16_t ip_id;
104
105 #if LWIP_MULTICAST_TX_OPTIONS
106 /** The default netif used for multicast */
107 static struct netif* ip4_default_multicast_netif;
108
109 /**
110 * @ingroup ip4
111 * Set a default netif for IPv4 multicast. */
112 void
ip4_set_default_multicast_netif(struct netif * default_multicast_netif)113 ip4_set_default_multicast_netif(struct netif* default_multicast_netif)
114 {
115 ip4_default_multicast_netif = default_multicast_netif;
116 }
117 #endif /* LWIP_MULTICAST_TX_OPTIONS */
118
119 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
120 /**
121 * Source based IPv4 routing must be fully implemented in
122 * LWIP_HOOK_IP4_ROUTE_SRC(). This function only provides he parameters.
123 */
124 struct netif *
ip4_route_src(const ip4_addr_t * dest,const ip4_addr_t * src)125 ip4_route_src(const ip4_addr_t *dest, const ip4_addr_t *src)
126 {
127 if (src != NULL) {
128 /* when src==NULL, the hook is called from ip4_route(dest) */
129 struct netif *netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, src);
130 if (netif != NULL) {
131 return netif;
132 }
133 #ifdef CELLULAR_SUPPORT
134 /* iterate through netifs */
135 for (netif = netif_list; netif != NULL; netif = netif->next) {
136 /* is the netif up, does it have a link and a valid address? */
137 if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
138 /* network mask matches? */
139 /* if src is netif address, use this netif directly. */
140 if (ip4_addr_cmp(src, netif_ip4_addr(netif))) {
141 /* return netif on which to forward IP packet */
142 return netif;
143 }
144 }
145 }
146 #endif /* CELLULAR_SUPPORT */
147 }
148 return ip4_route(dest);
149 }
150 #endif /* LWIP_HOOK_IP4_ROUTE_SRC */
151
152 /**
153 * Finds the appropriate network interface for a given IP address. It
154 * searches the list of network interfaces linearly. A match is found
155 * if the masked IP address of the network interface equals the masked
156 * IP address given to the function.
157 *
158 * @param dest the destination IP address for which to find the route
159 * @return the netif on which to send to reach dest
160 */
161 struct netif *
ip4_route(const ip4_addr_t * dest)162 ip4_route(const ip4_addr_t *dest)
163 {
164 struct netif *netif;
165
166 #if LWIP_MULTICAST_TX_OPTIONS
167 /* Use administratively selected interface for multicast by default */
168 if (ip4_addr_ismulticast(dest) && ip4_default_multicast_netif) {
169 return ip4_default_multicast_netif;
170 }
171 #endif /* LWIP_MULTICAST_TX_OPTIONS */
172
173 /* iterate through netifs */
174 for (netif = netif_list; netif != NULL; netif = netif->next) {
175 /* is the netif up, does it have a link and a valid address? */
176 if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
177 /* network mask matches? */
178 if (ip4_addr_netcmp(dest, netif_ip4_addr(netif), netif_ip4_netmask(netif))) {
179 /* return netif on which to forward IP packet */
180 return netif;
181 }
182 /* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */
183 if (((netif->flags & NETIF_FLAG_BROADCAST) == 0) && ip4_addr_cmp(dest, netif_ip4_gw(netif))) {
184 /* return netif on which to forward IP packet */
185 return netif;
186 }
187 }
188 }
189
190 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
191 /* loopif is disabled, looopback traffic is passed through any netif */
192 if (ip4_addr_isloopback(dest)) {
193 /* don't check for link on loopback traffic */
194 if (netif_is_up(netif_default)) {
195 return netif_default;
196 }
197 /* default netif is not up, just use any netif for loopback traffic */
198 for (netif = netif_list; netif != NULL; netif = netif->next) {
199 if (netif_is_up(netif)) {
200 return netif;
201 }
202 }
203 return NULL;
204 }
205 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
206
207 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
208 netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, NULL);
209 if (netif != NULL) {
210 return netif;
211 }
212 #elif defined(LWIP_HOOK_IP4_ROUTE)
213 netif = LWIP_HOOK_IP4_ROUTE(dest);
214 if (netif != NULL) {
215 return netif;
216 }
217 #endif
218
219 if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default) ||
220 ip4_addr_isany_val(*netif_ip4_addr(netif_default))) {
221 /* No matching netif found and default netif is not usable.
222 If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
223 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
224 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
225 IP_STATS_INC(ip.rterr);
226 MIB2_STATS_INC(mib2.ipoutnoroutes);
227 return NULL;
228 }
229
230 return netif_default;
231 }
232
233 #if IP_FORWARD
234 /**
235 * Determine whether an IP address is in a reserved set of addresses
236 * that may not be forwarded, or whether datagrams to that destination
237 * may be forwarded.
238 * @param p the packet to forward
239 * @return 1: can forward 0: discard
240 */
241 static int
ip4_canforward(struct pbuf * p)242 ip4_canforward(struct pbuf *p)
243 {
244 u32_t addr = lwip_htonl(ip4_addr_get_u32(ip4_current_dest_addr()));
245
246 if (p->flags & PBUF_FLAG_LLBCAST) {
247 /* don't route link-layer broadcasts */
248 return 0;
249 }
250 if ((p->flags & PBUF_FLAG_LLMCAST) && !IP_MULTICAST(addr)) {
251 /* don't route link-layer multicasts unless the destination address is an IP
252 multicast address */
253 return 0;
254 }
255 if (IP_EXPERIMENTAL(addr)) {
256 return 0;
257 }
258 if (IP_CLASSA(addr)) {
259 u32_t net = addr & IP_CLASSA_NET;
260 if ((net == 0) || (net == ((u32_t)IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
261 /* don't route loopback packets */
262 return 0;
263 }
264 }
265 return 1;
266 }
267
268 /**
269 * Forwards an IP packet. It finds an appropriate route for the
270 * packet, decrements the TTL value of the packet, adjusts the
271 * checksum and outputs the packet on the appropriate interface.
272 *
273 * @param p the packet to forward (p->payload points to IP header)
274 * @param iphdr the IP header of the input packet
275 * @param inp the netif on which this packet was received
276 */
277 static void
ip4_forward(struct pbuf * p,struct ip_hdr * iphdr,struct netif * inp)278 ip4_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
279 {
280 struct netif *netif;
281
282 PERF_START;
283 LWIP_UNUSED_ARG(inp);
284
285 if (!ip4_canforward(p)) {
286 goto return_noroute;
287 }
288
289 /* RFC3927 2.7: do not forward link-local addresses */
290 if (ip4_addr_islinklocal(ip4_current_dest_addr())) {
291 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
292 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
293 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
294 goto return_noroute;
295 }
296
297 /* Find network interface where to forward this IP packet to. */
298 netif = ip4_route_src(ip4_current_dest_addr(), ip4_current_src_addr());
299 if (netif == NULL) {
300 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
301 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
302 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
303 /* @todo: send ICMP_DUR_NET? */
304 goto return_noroute;
305 }
306 #if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
307 /* Do not forward packets onto the same network interface on which
308 * they arrived. */
309 if (netif == inp) {
310 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not bouncing packets back on incoming interface.\n"));
311 goto return_noroute;
312 }
313 #endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
314
315 /* decrement TTL */
316 IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
317 /* send ICMP if TTL == 0 */
318 if (IPH_TTL(iphdr) == 0) {
319 MIB2_STATS_INC(mib2.ipinhdrerrors);
320 #if LWIP_ICMP
321 /* Don't send ICMP messages in response to ICMP messages */
322 if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
323 icmp_time_exceeded(p, ICMP_TE_TTL);
324 }
325 #endif /* LWIP_ICMP */
326 return;
327 }
328
329 /* Incrementally update the IP checksum. */
330 if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
331 IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1);
332 } else {
333 IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100));
334 }
335
336 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
337 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
338 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
339
340 IP_STATS_INC(ip.fw);
341 MIB2_STATS_INC(mib2.ipforwdatagrams);
342 IP_STATS_INC(ip.xmit);
343
344 PERF_STOP("ip4_forward");
345 /* don't fragment if interface has mtu set to 0 [loopif] */
346 if (netif->mtu && (p->tot_len > netif->mtu)) {
347 if ((IPH_OFFSET(iphdr) & PP_NTOHS(IP_DF)) == 0) {
348 #if IP_FRAG
349 ip4_frag(p, netif, ip4_current_dest_addr());
350 #else /* IP_FRAG */
351 /* @todo: send ICMP Destination Unreachable code 13 "Communication administratively prohibited"? */
352 #endif /* IP_FRAG */
353 } else {
354 #if LWIP_ICMP
355 /* send ICMP Destination Unreachable code 4: "Fragmentation Needed and DF Set" */
356 icmp_dest_unreach(p, ICMP_DUR_FRAG);
357 #endif /* LWIP_ICMP */
358 }
359 return;
360 }
361 /* transmit pbuf on chosen interface */
362 netif->output(netif, p, ip4_current_dest_addr());
363 return;
364 return_noroute:
365 MIB2_STATS_INC(mib2.ipoutnoroutes);
366 }
367 #endif /* IP_FORWARD */
368
369 /**
370 * This function is called by the network interface device driver when
371 * an IP packet is received. The function does the basic checks of the
372 * IP header such as packet size being at least larger than the header
373 * size etc. If the packet was not destined for us, the packet is
374 * forwarded (using ip_forward). The IP checksum is always checked.
375 *
376 * Finally, the packet is sent to the upper layer protocol input function.
377 *
378 * @param p the received IP packet (p->payload points to IP header)
379 * @param inp the netif on which this packet was received
380 * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
381 * processed, but currently always returns ERR_OK)
382 */
383 err_t
ip4_input(struct pbuf * p,struct netif * inp)384 ip4_input(struct pbuf *p, struct netif *inp)
385 {
386 struct ip_hdr *iphdr;
387 struct netif *netif;
388 u16_t iphdr_hlen;
389 u16_t iphdr_len;
390 #if IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP
391 int check_ip_src = 1;
392 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP */
393
394 LWIP_PKTDEBUGF("LwIP_recv", (void*)p, (void*)inp);
395
396 IP_STATS_INC(ip.recv);
397 MIB2_STATS_INC(mib2.ipinreceives);
398
399 /* identify the IP header */
400 iphdr = (struct ip_hdr *)p->payload;
401 if (IPH_V(iphdr) != 4) {
402 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", (u16_t)IPH_V(iphdr)));
403 ip4_debug_print(p);
404 pbuf_free(p);
405 IP_STATS_INC(ip.err);
406 IP_STATS_INC(ip.drop);
407 MIB2_STATS_INC(mib2.ipinhdrerrors);
408 return ERR_OK;
409 }
410
411 #ifdef LWIP_HOOK_IP4_INPUT
412 if (LWIP_HOOK_IP4_INPUT(p, inp)) {
413 /* the packet has been eaten */
414 return ERR_OK;
415 }
416 #endif
417
418 /* obtain IP header length in number of 32-bit words */
419 iphdr_hlen = IPH_HL(iphdr);
420 /* calculate IP header length in bytes */
421 iphdr_hlen *= 4;
422 /* obtain ip length in bytes */
423 iphdr_len = lwip_ntohs(IPH_LEN(iphdr));
424
425 /* Trim pbuf. This is especially required for packets < 60 bytes. */
426 if (iphdr_len < p->tot_len) {
427 pbuf_realloc(p, iphdr_len);
428 }
429
430 /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
431 if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len) || (iphdr_hlen < IP_HLEN)) {
432 if (iphdr_hlen < IP_HLEN) {
433 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
434 ("ip4_input: short IP header (%"U16_F" bytes) received, IP packet dropped\n", iphdr_hlen));
435 }
436 if (iphdr_hlen > p->len) {
437 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
438 ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
439 iphdr_hlen, p->len));
440 }
441 if (iphdr_len > p->tot_len) {
442 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
443 ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
444 iphdr_len, p->tot_len));
445 }
446 /* free (drop) packet pbufs */
447 pbuf_free(p);
448 IP_STATS_INC(ip.lenerr);
449 IP_STATS_INC(ip.drop);
450 MIB2_STATS_INC(mib2.ipindiscards);
451 return ERR_OK;
452 }
453
454 /* verify checksum */
455 #if CHECKSUM_CHECK_IP
456 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_IP) {
457 if (inet_chksum(iphdr, iphdr_hlen) != 0) {
458
459 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
460 ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
461 ip4_debug_print(p);
462 pbuf_free(p);
463 IP_STATS_INC(ip.chkerr);
464 IP_STATS_INC(ip.drop);
465 MIB2_STATS_INC(mib2.ipinhdrerrors);
466 return ERR_OK;
467 }
468 }
469 #endif
470
471 /* copy IP addresses to aligned ip_addr_t */
472 ip_addr_copy_from_ip4(ip_data.current_iphdr_dest, iphdr->dest);
473 ip_addr_copy_from_ip4(ip_data.current_iphdr_src, iphdr->src);
474
475 /* match packet against an interface, i.e. is this packet for us? */
476 if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
477 #if LWIP_IGMP
478 if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ip4_current_dest_addr()))) {
479 /* IGMP snooping switches need 0.0.0.0 to be allowed as source address (RFC 4541) */
480 ip4_addr_t allsystems;
481 IP4_ADDR(&allsystems, 224, 0, 0, 1);
482 if (ip4_addr_cmp(ip4_current_dest_addr(), &allsystems) &&
483 ip4_addr_isany(ip4_current_src_addr())) {
484 check_ip_src = 0;
485 }
486 netif = inp;
487 } else {
488 netif = NULL;
489 }
490 #else /* LWIP_IGMP */
491 if ((netif_is_up(inp)) && (!ip4_addr_isany_val(*netif_ip4_addr(inp)))) {
492 netif = inp;
493 } else {
494 netif = NULL;
495 }
496 #endif /* LWIP_IGMP */
497 } else {
498 /* start trying with inp. if that's not acceptable, start walking the
499 list of configured netifs.
500 'first' is used as a boolean to mark whether we started walking the list */
501 int first = 1;
502 netif = inp;
503 do {
504 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",
505 ip4_addr_get_u32(&iphdr->dest), ip4_addr_get_u32(netif_ip4_addr(netif)),
506 ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
507 ip4_addr_get_u32(netif_ip4_addr(netif)) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
508 ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(netif_ip4_netmask(netif))));
509
510 /* interface is up and configured? */
511 if ((netif_is_up(netif)) && (!ip4_addr_isany_val(*netif_ip4_addr(netif)))) {
512 /* unicast to this interface address? */
513 if (ip4_addr_cmp(ip4_current_dest_addr(), netif_ip4_addr(netif)) ||
514 /* or broadcast on this interface network address? */
515 ip4_addr_isbroadcast(ip4_current_dest_addr(), netif)
516 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
517 || (ip4_addr_get_u32(ip4_current_dest_addr()) == PP_HTONL(IPADDR_LOOPBACK))
518 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
519 ) {
520 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: packet accepted on interface %c%c\n",
521 netif->name[0], netif->name[1]));
522 /* break out of for loop */
523 break;
524 }
525 #if LWIP_AUTOIP
526 /* connections to link-local addresses must persist after changing
527 the netif's address (RFC3927 ch. 1.9) */
528 if (autoip_accept_packet(netif, ip4_current_dest_addr())) {
529 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: LLA packet accepted on interface %c%c\n",
530 netif->name[0], netif->name[1]));
531 /* break out of for loop */
532 break;
533 }
534 #endif /* LWIP_AUTOIP */
535 }
536 if (first) {
537 first = 0;
538 netif = netif_list;
539 } else {
540 netif = netif->next;
541 }
542 if (netif == inp) {
543 netif = netif->next;
544 }
545 } while (netif != NULL);
546 }
547
548 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
549 /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
550 * using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
551 * According to RFC 1542 section 3.1.1, referred by RFC 2131).
552 *
553 * If you want to accept private broadcast communication while a netif is down,
554 * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
555 *
556 * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
557 */
558 if (netif == NULL) {
559 /* remote port is DHCP server? */
560 if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
561 struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen);
562 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: UDP packet to DHCP client port %"U16_F"\n",
563 lwip_ntohs(udphdr->dest)));
564 if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
565 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: DHCP packet accepted.\n"));
566 netif = inp;
567 check_ip_src = 0;
568 }
569 }
570 }
571 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
572
573 /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
574 #if LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING
575 if (check_ip_src
576 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
577 /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
578 && !ip4_addr_isany_val(*ip4_current_src_addr())
579 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
580 )
581 #endif /* LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING */
582 {
583 if ((ip4_addr_isbroadcast(ip4_current_src_addr(), inp)) ||
584 (ip4_addr_ismulticast(ip4_current_src_addr()))) {
585 /* packet source is not valid */
586 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip4_input: packet source is not valid.\n"));
587 /* free (drop) packet pbufs */
588 pbuf_free(p);
589 IP_STATS_INC(ip.drop);
590 MIB2_STATS_INC(mib2.ipinaddrerrors);
591 MIB2_STATS_INC(mib2.ipindiscards);
592 return ERR_OK;
593 }
594 }
595
596 /* packet not for us? */
597 if (netif == NULL) {
598 /* packet not for us, route or discard */
599 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: packet not for us.\n"));
600 #if IP_FORWARD
601 /* non-broadcast packet? */
602 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), inp)) {
603 /* try to forward IP packet on (other) interfaces */
604 ip4_forward(p, iphdr, inp);
605 } else
606 #endif /* IP_FORWARD */
607 {
608 MIB2_STATS_INC(mib2.ipinaddrerrors);
609 MIB2_STATS_INC(mib2.ipindiscards);
610 }
611 pbuf_free(p);
612 return ERR_OK;
613 }
614 /* packet consists of multiple fragments? */
615 if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) {
616 #if IP_REASSEMBLY /* packet fragment reassembly code present? */
617 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",
618 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)));
619 /* reassemble the packet*/
620 p = ip4_reass(p);
621 /* packet not fully reassembled yet? */
622 if (p == NULL) {
623 return ERR_OK;
624 }
625 iphdr = (struct ip_hdr *)p->payload;
626 #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
627 pbuf_free(p);
628 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
629 lwip_ntohs(IPH_OFFSET(iphdr))));
630 IP_STATS_INC(ip.opterr);
631 IP_STATS_INC(ip.drop);
632 /* unsupported protocol feature */
633 MIB2_STATS_INC(mib2.ipinunknownprotos);
634 return ERR_OK;
635 #endif /* IP_REASSEMBLY */
636 }
637
638 #if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
639
640 #if LWIP_IGMP
641 /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
642 if ((iphdr_hlen > IP_HLEN) && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
643 #else
644 if (iphdr_hlen > IP_HLEN) {
645 #endif /* LWIP_IGMP */
646 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
647 pbuf_free(p);
648 IP_STATS_INC(ip.opterr);
649 IP_STATS_INC(ip.drop);
650 /* unsupported protocol feature */
651 MIB2_STATS_INC(mib2.ipinunknownprotos);
652 return ERR_OK;
653 }
654 #endif /* IP_OPTIONS_ALLOWED == 0 */
655
656 /* send to upper layers */
657 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: \n"));
658 ip4_debug_print(p);
659 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
660
661 ip_data.current_netif = netif;
662 ip_data.current_input_netif = inp;
663 ip_data.current_ip4_header = iphdr;
664 ip_data.current_ip_header_tot_len = IPH_HL(iphdr) * 4;
665
666 #if LWIP_RAW
667 /* raw input did not eat the packet? */
668 if (raw_input(p, inp) == 0)
669 #endif /* LWIP_RAW */
670 {
671 pbuf_header(p, -(s16_t)iphdr_hlen); /* Move to payload, no check necessary. */
672
673 switch (IPH_PROTO(iphdr)) {
674 #if LWIP_UDP
675 case IP_PROTO_UDP:
676 #if LWIP_UDPLITE
677 case IP_PROTO_UDPLITE:
678 #endif /* LWIP_UDPLITE */
679 MIB2_STATS_INC(mib2.ipindelivers);
680 udp_input(p, inp);
681 break;
682 #endif /* LWIP_UDP */
683 #if LWIP_TCP
684 case IP_PROTO_TCP:
685 MIB2_STATS_INC(mib2.ipindelivers);
686 tcp_input(p, inp);
687 break;
688 #endif /* LWIP_TCP */
689 #if LWIP_ICMP
690 case IP_PROTO_ICMP:
691 MIB2_STATS_INC(mib2.ipindelivers);
692 icmp_input(p, inp);
693 break;
694 #endif /* LWIP_ICMP */
695 #if LWIP_IGMP
696 case IP_PROTO_IGMP:
697 igmp_input(p, inp, ip4_current_dest_addr());
698 break;
699 #endif /* LWIP_IGMP */
700 default:
701 #if LWIP_ICMP
702 /* send ICMP destination protocol unreachable unless is was a broadcast */
703 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), netif) &&
704 !ip4_addr_ismulticast(ip4_current_dest_addr())) {
705 pbuf_header_force(p, iphdr_hlen); /* Move to ip header, no check necessary. */
706 p->payload = iphdr;
707 icmp_dest_unreach(p, ICMP_DUR_PROTO);
708 }
709 #endif /* LWIP_ICMP */
710 pbuf_free(p);
711
712 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", (u16_t)IPH_PROTO(iphdr)));
713
714 IP_STATS_INC(ip.proterr);
715 IP_STATS_INC(ip.drop);
716 MIB2_STATS_INC(mib2.ipinunknownprotos);
717 }
718 }
719
720 /* @todo: this is not really necessary... */
721 ip_data.current_netif = NULL;
722 ip_data.current_input_netif = NULL;
723 ip_data.current_ip4_header = NULL;
724 ip_data.current_ip_header_tot_len = 0;
725 ip4_addr_set_any(ip4_current_src_addr());
726 ip4_addr_set_any(ip4_current_dest_addr());
727
728 return ERR_OK;
729 }
730
731 /**
732 * Sends an IP packet on a network interface. This function constructs
733 * the IP header and calculates the IP header checksum. If the source
734 * IP address is NULL, the IP address of the outgoing network
735 * interface is filled in as source address.
736 * If the destination IP address is LWIP_IP_HDRINCL, p is assumed to already
737 * include an IP header and p->payload points to it instead of the data.
738 *
739 * @param p the packet to send (p->payload points to the data, e.g. next
740 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
741 IP header and p->payload points to that IP header)
742 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
743 * IP address of the netif used to send is used as source address)
744 * @param dest the destination IP address to send the packet to
745 * @param ttl the TTL value to be set in the IP header
746 * @param tos the TOS value to be set in the IP header
747 * @param proto the PROTOCOL to be set in the IP header
748 * @param netif the netif on which to send this packet
749 * @return ERR_OK if the packet was sent OK
750 * ERR_BUF if p doesn't have enough space for IP/LINK headers
751 * returns errors returned by netif->output
752 *
753 * @note ip_id: RFC791 "some host may be able to simply use
754 * unique identifiers independent of destination"
755 */
756 err_t
757 ip4_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
758 u8_t ttl, u8_t tos,
759 u8_t proto, struct netif *netif)
760 {
761 #if IP_OPTIONS_SEND
762 return ip4_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
763 }
764
765 /**
766 * Same as ip_output_if() but with the possibility to include IP options:
767 *
768 * @ param ip_options pointer to the IP options, copied into the IP header
769 * @ param optlen length of ip_options
770 */
771 err_t
772 ip4_output_if_opt(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
773 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
774 u16_t optlen)
775 {
776 #endif /* IP_OPTIONS_SEND */
777 const ip4_addr_t *src_used = src;
778 if (dest != LWIP_IP_HDRINCL) {
779 if (ip4_addr_isany(src)) {
780 src_used = netif_ip4_addr(netif);
781 }
782 }
783
784 #if IP_OPTIONS_SEND
785 return ip4_output_if_opt_src(p, src_used, dest, ttl, tos, proto, netif,
786 ip_options, optlen);
787 #else /* IP_OPTIONS_SEND */
788 return ip4_output_if_src(p, src_used, dest, ttl, tos, proto, netif);
789 #endif /* IP_OPTIONS_SEND */
790 }
791
792 /**
793 * Same as ip_output_if() but 'src' address is not replaced by netif address
794 * when it is 'any'.
795 */
796 err_t
797 ip4_output_if_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
798 u8_t ttl, u8_t tos,
799 u8_t proto, struct netif *netif)
800 {
801 #if IP_OPTIONS_SEND
802 return ip4_output_if_opt_src(p, src, dest, ttl, tos, proto, netif, NULL, 0);
803 }
804
805 /**
806 * Same as ip_output_if_opt() but 'src' address is not replaced by netif address
807 * when it is 'any'.
808 */
809 err_t
810 ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
811 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
812 u16_t optlen)
813 {
814 #endif /* IP_OPTIONS_SEND */
815 struct ip_hdr *iphdr;
816 ip4_addr_t dest_addr;
817 #if CHECKSUM_GEN_IP_INLINE
818 u32_t chk_sum = 0;
819 #endif /* CHECKSUM_GEN_IP_INLINE */
820
821 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
822
823 MIB2_STATS_INC(mib2.ipoutrequests);
824
825 /* Should the IP header be generated or is it already included in p? */
826 if (dest != LWIP_IP_HDRINCL) {
827 u16_t ip_hlen = IP_HLEN;
828 #if IP_OPTIONS_SEND
829 u16_t optlen_aligned = 0;
830 if (optlen != 0) {
831 #if CHECKSUM_GEN_IP_INLINE
832 int i;
833 #endif /* CHECKSUM_GEN_IP_INLINE */
834 /* round up to a multiple of 4 */
835 optlen_aligned = ((optlen + 3) & ~3);
836 ip_hlen += optlen_aligned;
837 /* First write in the IP options */
838 if (pbuf_header(p, optlen_aligned)) {
839 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: not enough room for IP options in pbuf\n"));
840 IP_STATS_INC(ip.err);
841 MIB2_STATS_INC(mib2.ipoutdiscards);
842 return ERR_BUF;
843 }
844 MEMCPY(p->payload, ip_options, optlen);
845 if (optlen < optlen_aligned) {
846 /* zero the remaining bytes */
847 memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen);
848 }
849 #if CHECKSUM_GEN_IP_INLINE
850 for (i = 0; i < optlen_aligned/2; i++) {
851 chk_sum += ((u16_t*)p->payload)[i];
852 }
853 #endif /* CHECKSUM_GEN_IP_INLINE */
854 }
855 #endif /* IP_OPTIONS_SEND */
856 /* generate IP header */
857 if (pbuf_header(p, IP_HLEN)) {
858 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: not enough room for IP header in pbuf\n"));
859
860 IP_STATS_INC(ip.err);
861 MIB2_STATS_INC(mib2.ipoutdiscards);
862 return ERR_BUF;
863 }
864
865 iphdr = (struct ip_hdr *)p->payload;
866 LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
867 (p->len >= sizeof(struct ip_hdr)));
868
869 IPH_TTL_SET(iphdr, ttl);
870 IPH_PROTO_SET(iphdr, proto);
871 #if CHECKSUM_GEN_IP_INLINE
872 chk_sum += LWIP_MAKE_U16(proto, ttl);
873 #endif /* CHECKSUM_GEN_IP_INLINE */
874
875 /* dest cannot be NULL here */
876 ip4_addr_copy(iphdr->dest, *dest);
877 #if CHECKSUM_GEN_IP_INLINE
878 chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
879 chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
880 #endif /* CHECKSUM_GEN_IP_INLINE */
881
882 IPH_VHL_SET(iphdr, 4, ip_hlen / 4);
883 IPH_TOS_SET(iphdr, tos);
884 #if CHECKSUM_GEN_IP_INLINE
885 chk_sum += LWIP_MAKE_U16(tos, iphdr->_v_hl);
886 #endif /* CHECKSUM_GEN_IP_INLINE */
887 IPH_LEN_SET(iphdr, lwip_htons(p->tot_len));
888 #if CHECKSUM_GEN_IP_INLINE
889 chk_sum += iphdr->_len;
890 #endif /* CHECKSUM_GEN_IP_INLINE */
891 IPH_OFFSET_SET(iphdr, 0);
892 IPH_ID_SET(iphdr, lwip_htons(ip_id));
893 #if CHECKSUM_GEN_IP_INLINE
894 chk_sum += iphdr->_id;
895 #endif /* CHECKSUM_GEN_IP_INLINE */
896 ++ip_id;
897
898 if (src == NULL) {
899 ip4_addr_copy(iphdr->src, *IP4_ADDR_ANY4);
900 } else {
901 /* src cannot be NULL here */
902 ip4_addr_copy(iphdr->src, *src);
903 }
904
905 #if CHECKSUM_GEN_IP_INLINE
906 chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
907 chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
908 chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
909 chk_sum = (chk_sum >> 16) + chk_sum;
910 chk_sum = ~chk_sum;
911 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
912 iphdr->_chksum = (u16_t)chk_sum; /* network order */
913 }
914 #if LWIP_CHECKSUM_CTRL_PER_NETIF
915 else {
916 IPH_CHKSUM_SET(iphdr, 0);
917 }
918 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF*/
919 #else /* CHECKSUM_GEN_IP_INLINE */
920 IPH_CHKSUM_SET(iphdr, 0);
921 #if CHECKSUM_GEN_IP
922 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
923 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
924 }
925 #endif /* CHECKSUM_GEN_IP */
926 #endif /* CHECKSUM_GEN_IP_INLINE */
927 } else {
928 /* IP header already included in p */
929 iphdr = (struct ip_hdr *)p->payload;
930 ip4_addr_copy(dest_addr, iphdr->dest);
931 dest = &dest_addr;
932 }
933
934 IP_STATS_INC(ip.xmit);
935
936 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
937 ip4_debug_print(p);
938
939 LWIP_PKTDEBUGF("LwIP_send", (void*)p, (void*)netif);
940
941 #if ENABLE_LOOPBACK
942 if (ip4_addr_cmp(dest, netif_ip4_addr(netif))
943 #if !LWIP_HAVE_LOOPIF
944 || ip4_addr_isloopback(dest)
945 #endif /* !LWIP_HAVE_LOOPIF */
946 ) {
947 /* Packet to self, enqueue it for loopback */
948 LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
949 return netif_loop_output(netif, p);
950 }
951 #if LWIP_MULTICAST_TX_OPTIONS
952 if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
953 netif_loop_output(netif, p);
954 }
955 #endif /* LWIP_MULTICAST_TX_OPTIONS */
956 #endif /* ENABLE_LOOPBACK */
957 #if IP_FRAG
958 /* don't fragment if interface has mtu set to 0 [loopif] */
959 if (netif->mtu && (p->tot_len > netif->mtu)) {
960 return ip4_frag(p, netif, dest);
961 }
962 #endif /* IP_FRAG */
963
964 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));
965 return netif->output(netif, p, dest);
966 }
967
968 /**
969 * Simple interface to ip_output_if. It finds the outgoing network
970 * interface and calls upon ip_output_if to do the actual work.
971 *
972 * @param p the packet to send (p->payload points to the data, e.g. next
973 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
974 IP header and p->payload points to that IP header)
975 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
976 * IP address of the netif used to send is used as source address)
977 * @param dest the destination IP address to send the packet to
978 * @param ttl the TTL value to be set in the IP header
979 * @param tos the TOS value to be set in the IP header
980 * @param proto the PROTOCOL to be set in the IP header
981 *
982 * @return ERR_RTE if no route is found
983 * see ip_output_if() for more return values
984 */
985 err_t
986 ip4_output(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
987 u8_t ttl, u8_t tos, u8_t proto)
988 {
989 struct netif *netif;
990
991 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
992
993 if ((netif = ip4_route_src(dest, src)) == NULL) {
994 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
995 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
996 IP_STATS_INC(ip.rterr);
997 return ERR_RTE;
998 }
999
1000 return ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1001 }
1002
1003 #if LWIP_NETIF_HWADDRHINT
1004 /** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
1005 * before calling ip_output_if.
1006 *
1007 * @param p the packet to send (p->payload points to the data, e.g. next
1008 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
1009 IP header and p->payload points to that IP header)
1010 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
1011 * IP address of the netif used to send is used as source address)
1012 * @param dest the destination IP address to send the packet to
1013 * @param ttl the TTL value to be set in the IP header
1014 * @param tos the TOS value to be set in the IP header
1015 * @param proto the PROTOCOL to be set in the IP header
1016 * @param addr_hint address hint pointer set to netif->addr_hint before
1017 * calling ip_output_if()
1018 *
1019 * @return ERR_RTE if no route is found
1020 * see ip_output_if() for more return values
1021 */
1022 err_t
1023 ip4_output_hinted(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
1024 u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
1025 {
1026 struct netif *netif;
1027 err_t err;
1028
1029 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
1030
1031 if ((netif = ip4_route_src(dest, src)) == NULL) {
1032 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1033 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
1034 IP_STATS_INC(ip.rterr);
1035 return ERR_RTE;
1036 }
1037
1038 NETIF_SET_HWADDRHINT(netif, addr_hint);
1039 err = ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1040 NETIF_SET_HWADDRHINT(netif, NULL);
1041
1042 return err;
1043 }
1044 #endif /* LWIP_NETIF_HWADDRHINT*/
1045
1046 #if IP_DEBUG
1047 /* Print an IP header by using LWIP_DEBUGF
1048 * @param p an IP packet, p->payload pointing to the IP header
1049 */
1050 void
1051 ip4_debug_print(struct pbuf *p)
1052 {
1053 struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
1054
1055 (void)iphdr;
1056 LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
1057 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1058 LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n",
1059 (u16_t)IPH_V(iphdr),
1060 (u16_t)IPH_HL(iphdr),
1061 (u16_t)IPH_TOS(iphdr),
1062 lwip_ntohs(IPH_LEN(iphdr))));
1063 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1064 LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n",
1065 lwip_ntohs(IPH_ID(iphdr)),
1066 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 15 & 1),
1067 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 14 & 1),
1068 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 13 & 1),
1069 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)));
1070 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1071 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n",
1072 (u16_t)IPH_TTL(iphdr),
1073 (u16_t)IPH_PROTO(iphdr),
1074 lwip_ntohs(IPH_CHKSUM(iphdr))));
1075 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1076 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n",
1077 ip4_addr1_16(&iphdr->src),
1078 ip4_addr2_16(&iphdr->src),
1079 ip4_addr3_16(&iphdr->src),
1080 ip4_addr4_16(&iphdr->src)));
1081 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1082 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n",
1083 ip4_addr1_16(&iphdr->dest),
1084 ip4_addr2_16(&iphdr->dest),
1085 ip4_addr3_16(&iphdr->dest),
1086 ip4_addr4_16(&iphdr->dest)));
1087 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1088 }
1089 #endif /* IP_DEBUG */
1090
1091 #endif /* LWIP_IPV4 */
1092