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1 office 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/iana.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(LWIP_IANA_PORT_DHCP_CLIENT)) \
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(LWIP_IANA_PORT_DHCP_CLIENT))
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
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 the parameters.
127 */
128 struct netif *
129 ip4_route_src(const ip4_addr_t *src, const ip4_addr_t *dest)
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(src, dest);
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 *
152 ip4_route(const ip4_addr_t *dest)
153 {
154 #if !LWIP_SINGLE_NETIF
155 struct netif *netif;
156  
157 #if LWIP_MULTICAST_TX_OPTIONS
158 /* Use administratively selected interface for multicast by default */
159 if (ip4_addr_ismulticast(dest) && ip4_default_multicast_netif) {
160 return ip4_default_multicast_netif;
161 }
162 #endif /* LWIP_MULTICAST_TX_OPTIONS */
163  
164 /* iterate through netifs */
165 for (netif = netif_list; netif != NULL; netif = netif->next) {
166 /* is the netif up, does it have a link and a valid address? */
167 if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
168 /* network mask matches? */
169 if (ip4_addr_netcmp(dest, netif_ip4_addr(netif), netif_ip4_netmask(netif))) {
170 /* return netif on which to forward IP packet */
171 return netif;
172 }
173 /* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */
174 if (((netif->flags & NETIF_FLAG_BROADCAST) == 0) && ip4_addr_cmp(dest, netif_ip4_gw(netif))) {
175 /* return netif on which to forward IP packet */
176 return netif;
177 }
178 }
179 }
180  
181 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
182 /* loopif is disabled, looopback traffic is passed through any netif */
183 if (ip4_addr_isloopback(dest)) {
184 /* don't check for link on loopback traffic */
185 if (netif_default != NULL && netif_is_up(netif_default)) {
186 return netif_default;
187 }
188 /* default netif is not up, just use any netif for loopback traffic */
189 for (netif = netif_list; netif != NULL; netif = netif->next) {
190 if (netif_is_up(netif)) {
191 return netif;
192 }
193 }
194 return NULL;
195 }
196 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
197  
198 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
199 netif = LWIP_HOOK_IP4_ROUTE_SRC(NULL, dest);
200 if (netif != NULL) {
201 return netif;
202 }
203 #elif defined(LWIP_HOOK_IP4_ROUTE)
204 netif = LWIP_HOOK_IP4_ROUTE(dest);
205 if (netif != NULL) {
206 return netif;
207 }
208 #endif
209 #endif /* !LWIP_SINGLE_NETIF */
210  
211 if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default)
212 /* Yes we are binding to any addr */
213 // || ip4_addr_isany_val(*netif_ip4_addr(netif_default))
214 ) {
215 /* No matching netif found and default netif is not usable.
216 If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
217 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
218 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
219 IP_STATS_INC(ip.rterr);
220 MIB2_STATS_INC(mib2.ipoutnoroutes);
221 return NULL;
222 }
223  
224 return netif_default;
225 }
226  
227 #if IP_FORWARD
228 /**
229 * Determine whether an IP address is in a reserved set of addresses
230 * that may not be forwarded, or whether datagrams to that destination
231 * may be forwarded.
232 * @param p the packet to forward
233 * @return 1: can forward 0: discard
234 */
235 static int
236 ip4_canforward(struct pbuf *p)
237 {
238 u32_t addr = lwip_htonl(ip4_addr_get_u32(ip4_current_dest_addr()));
239  
240 if (p->flags & PBUF_FLAG_LLBCAST) {
241 /* don't route link-layer broadcasts */
242 return 0;
243 }
244 if ((p->flags & PBUF_FLAG_LLMCAST) && !IP_MULTICAST(addr)) {
245 /* don't route link-layer multicasts unless the destination address is an IP
246 multicast address */
247 return 0;
248 }
249 if (IP_EXPERIMENTAL(addr)) {
250 return 0;
251 }
252 if (IP_CLASSA(addr)) {
253 u32_t net = addr & IP_CLASSA_NET;
254 if ((net == 0) || (net == ((u32_t)IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
255 /* don't route loopback packets */
256 return 0;
257 }
258 }
259 return 1;
260 }
261  
262 /**
263 * Forwards an IP packet. It finds an appropriate route for the
264 * packet, decrements the TTL value of the packet, adjusts the
265 * checksum and outputs the packet on the appropriate interface.
266 *
267 * @param p the packet to forward (p->payload points to IP header)
268 * @param iphdr the IP header of the input packet
269 * @param inp the netif on which this packet was received
270 */
271 static void
272 ip4_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
273 {
274 struct netif *netif;
275  
276 PERF_START;
277 LWIP_UNUSED_ARG(inp);
278  
279 if (!ip4_canforward(p)) {
280 goto return_noroute;
281 }
282  
283 /* RFC3927 2.7: do not forward link-local addresses */
284 if (ip4_addr_islinklocal(ip4_current_dest_addr())) {
285 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
286 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
287 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
288 goto return_noroute;
289 }
290  
291 /* Find network interface where to forward this IP packet to. */
292 netif = ip4_route_src(ip4_current_src_addr(), ip4_current_dest_addr());
293 if (netif == NULL) {
294 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
295 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
296 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
297 /* @todo: send ICMP_DUR_NET? */
298 goto return_noroute;
299 }
300 #if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
301 /* Do not forward packets onto the same network interface on which
302 * they arrived. */
303 if (netif == inp) {
304 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not bouncing packets back on incoming interface.\n"));
305 goto return_noroute;
306 }
307 #endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
308  
309 /* decrement TTL */
310 IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
311 /* send ICMP if TTL == 0 */
312 if (IPH_TTL(iphdr) == 0) {
313 MIB2_STATS_INC(mib2.ipinhdrerrors);
314 #if LWIP_ICMP
315 /* Don't send ICMP messages in response to ICMP messages */
316 if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
317 icmp_time_exceeded(p, ICMP_TE_TTL);
318 }
319 #endif /* LWIP_ICMP */
320 return;
321 }
322  
323 /* Incrementally update the IP checksum. */
324 if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
325 IPH_CHKSUM_SET(iphdr, (u16_t)(IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1));
326 } else {
327 IPH_CHKSUM_SET(iphdr, (u16_t)(IPH_CHKSUM(iphdr) + PP_HTONS(0x100)));
328 }
329  
330 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
331 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
332 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
333  
334 IP_STATS_INC(ip.fw);
335 MIB2_STATS_INC(mib2.ipforwdatagrams);
336 IP_STATS_INC(ip.xmit);
337  
338 PERF_STOP("ip4_forward");
339 /* don't fragment if interface has mtu set to 0 [loopif] */
340 if (netif->mtu && (p->tot_len > netif->mtu)) {
341 if ((IPH_OFFSET(iphdr) & PP_NTOHS(IP_DF)) == 0) {
342 #if IP_FRAG
343 ip4_frag(p, netif, ip4_current_dest_addr());
344 #else /* IP_FRAG */
345 /* @todo: send ICMP Destination Unreachable code 13 "Communication administratively prohibited"? */
346 #endif /* IP_FRAG */
347 } else {
348 #if LWIP_ICMP
349 /* send ICMP Destination Unreachable code 4: "Fragmentation Needed and DF Set" */
350 icmp_dest_unreach(p, ICMP_DUR_FRAG);
351 #endif /* LWIP_ICMP */
352 }
353 return;
354 }
355 /* transmit pbuf on chosen interface */
356 netif->output(netif, p, ip4_current_dest_addr());
357 return;
358 return_noroute:
359 MIB2_STATS_INC(mib2.ipoutnoroutes);
360 }
361 #endif /* IP_FORWARD */
362  
363 /** Return true if the current input packet should be accepted on this netif */
364 static int
365 ip4_input_accept(struct netif *netif)
366 {
367 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",
368 ip4_addr_get_u32(ip4_current_dest_addr()), ip4_addr_get_u32(netif_ip4_addr(netif)),
369 ip4_addr_get_u32(ip4_current_dest_addr()) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
370 ip4_addr_get_u32(netif_ip4_addr(netif)) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
371 ip4_addr_get_u32(ip4_current_dest_addr()) & ~ip4_addr_get_u32(netif_ip4_netmask(netif))));
372  
373 /* interface is up and configured? */
374 if ((netif_is_up(netif)) && (!ip4_addr_isany_val(*netif_ip4_addr(netif)))) {
375 /* unicast to this interface address? */
376 if (ip4_addr_cmp(ip4_current_dest_addr(), netif_ip4_addr(netif)) ||
377 /* or broadcast on this interface network address? */
378 ip4_addr_isbroadcast(ip4_current_dest_addr(), netif)
379 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
380 || (ip4_addr_get_u32(ip4_current_dest_addr()) == PP_HTONL(IPADDR_LOOPBACK))
381 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
382 ) {
383 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: packet accepted on interface %c%c\n",
384 netif->name[0], netif->name[1]));
385 /* accept on this netif */
386 return 1;
387 }
388 #if LWIP_AUTOIP
389 /* connections to link-local addresses must persist after changing
390 the netif's address (RFC3927 ch. 1.9) */
391 if (autoip_accept_packet(netif, ip4_current_dest_addr())) {
392 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: LLA packet accepted on interface %c%c\n",
393 netif->name[0], netif->name[1]));
394 /* accept on this netif */
395 return 1;
396 }
397 #endif /* LWIP_AUTOIP */
398 }
399 return 0;
400 }
401  
402 /**
403 * This function is called by the network interface device driver when
404 * an IP packet is received. The function does the basic checks of the
405 * IP header such as packet size being at least larger than the header
406 * size etc. If the packet was not destined for us, the packet is
407 * forwarded (using ip_forward). The IP checksum is always checked.
408 *
409 * Finally, the packet is sent to the upper layer protocol input function.
410 *
411 * @param p the received IP packet (p->payload points to IP header)
412 * @param inp the netif on which this packet was received
413 * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
414 * processed, but currently always returns ERR_OK)
415 */
416 err_t
417 ip4_input(struct pbuf *p, struct netif *inp)
418 {
419 const struct ip_hdr *iphdr;
420 struct netif *netif;
421 u16_t iphdr_hlen;
422 u16_t iphdr_len;
423 #if IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP
424 int check_ip_src = 1;
425 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP */
426  
427 IP_STATS_INC(ip.recv);
428 MIB2_STATS_INC(mib2.ipinreceives);
429  
430 /* identify the IP header */
431 iphdr = (struct ip_hdr *)p->payload;
432 if (IPH_V(iphdr) != 4) {
433 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", (u16_t)IPH_V(iphdr)));
434 ip4_debug_print(p);
435 pbuf_free(p);
436 IP_STATS_INC(ip.err);
437 IP_STATS_INC(ip.drop);
438 MIB2_STATS_INC(mib2.ipinhdrerrors);
439 return ERR_OK;
440 }
441  
442 #ifdef LWIP_HOOK_IP4_INPUT
443 if (LWIP_HOOK_IP4_INPUT(p, inp)) {
444 /* the packet has been eaten */
445 return ERR_OK;
446 }
447 #endif
448  
449 /* obtain IP header length in bytes */
450 iphdr_hlen = IPH_HL_BYTES(iphdr);
451 /* obtain ip length in bytes */
452 iphdr_len = lwip_ntohs(IPH_LEN(iphdr));
453  
454 /* Trim pbuf. This is especially required for packets < 60 bytes. */
455 if (iphdr_len < p->tot_len) {
456 pbuf_realloc(p, iphdr_len);
457 }
458  
459 /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
460 if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len) || (iphdr_hlen < IP_HLEN)) {
461 if (iphdr_hlen < IP_HLEN) {
462 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
463 ("ip4_input: short IP header (%"U16_F" bytes) received, IP packet dropped\n", iphdr_hlen));
464 }
465 if (iphdr_hlen > p->len) {
466 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
467 ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
468 iphdr_hlen, p->len));
469 }
470 if (iphdr_len > p->tot_len) {
471 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
472 ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
473 iphdr_len, p->tot_len));
474 }
475 /* free (drop) packet pbufs */
476 pbuf_free(p);
477 IP_STATS_INC(ip.lenerr);
478 IP_STATS_INC(ip.drop);
479 MIB2_STATS_INC(mib2.ipindiscards);
480 return ERR_OK;
481 }
482  
483 /* verify checksum */
484 #if CHECKSUM_CHECK_IP
485 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_IP) {
486 if (inet_chksum(iphdr, iphdr_hlen) != 0) {
487  
488 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
489 ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
490 ip4_debug_print(p);
491 pbuf_free(p);
492 IP_STATS_INC(ip.chkerr);
493 IP_STATS_INC(ip.drop);
494 MIB2_STATS_INC(mib2.ipinhdrerrors);
495 return ERR_OK;
496 }
497 }
498 #endif
499  
500 /* copy IP addresses to aligned ip_addr_t */
501 ip_addr_copy_from_ip4(ip_data.current_iphdr_dest, iphdr->dest);
502 ip_addr_copy_from_ip4(ip_data.current_iphdr_src, iphdr->src);
503  
504 /* match packet against an interface, i.e. is this packet for us? */
505 if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
506 #if LWIP_IGMP
507 if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ip4_current_dest_addr()))) {
508 /* IGMP snooping switches need 0.0.0.0 to be allowed as source address (RFC 4541) */
509 ip4_addr_t allsystems;
510 IP4_ADDR(&allsystems, 224, 0, 0, 1);
511 if (ip4_addr_cmp(ip4_current_dest_addr(), &allsystems) &&
512 ip4_addr_isany(ip4_current_src_addr())) {
513 check_ip_src = 0;
514 }
515 netif = inp;
516 } else {
517 netif = NULL;
518 }
519 #else /* LWIP_IGMP */
520 if ((netif_is_up(inp)) && (!ip4_addr_isany_val(*netif_ip4_addr(inp)))) {
521 netif = inp;
522 } else {
523 netif = NULL;
524 }
525 #endif /* LWIP_IGMP */
526 } else {
527 /* start trying with inp. if that's not acceptable, start walking the
528 list of configured netifs. */
529 if (ip4_input_accept(inp)) {
530 netif = inp;
531 } else {
532 netif = NULL;
533 #if !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF
534 /* Packets sent to the loopback address must not be accepted on an
535 * interface that does not have the loopback address assigned to it,
536 * unless a non-loopback interface is used for loopback traffic. */
537 if (!ip4_addr_isloopback(ip4_current_dest_addr()))
538 #endif /* !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF */
539 {
540 #if !LWIP_SINGLE_NETIF
541 NETIF_FOREACH(netif) {
542 if (netif == inp) {
543 /* we checked that before already */
544 continue;
545 }
546 if (ip4_input_accept(netif)) {
547 break;
548 }
549 }
550 #endif /* !LWIP_SINGLE_NETIF */
551 }
552 }
553 }
554  
555 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
556 /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
557 * using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
558 * According to RFC 1542 section 3.1.1, referred by RFC 2131).
559 *
560 * If you want to accept private broadcast communication while a netif is down,
561 * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
562 *
563 * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
564 */
565 if (netif == NULL) {
566 /* remote port is DHCP server? */
567 if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
568 const struct udp_hdr *udphdr = (const struct udp_hdr *)((const u8_t *)iphdr + iphdr_hlen);
569 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: UDP packet to DHCP client port %"U16_F"\n",
570 lwip_ntohs(udphdr->dest)));
571 if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
572 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: DHCP packet accepted.\n"));
573 netif = inp;
574 check_ip_src = 0;
575 }
576 }
577 }
578 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
579  
580 /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
581 #if LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING
582 if (check_ip_src
583 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
584 /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
585 && !ip4_addr_isany_val(*ip4_current_src_addr())
586 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
587 )
588 #endif /* LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING */
589 {
590 if ((ip4_addr_isbroadcast(ip4_current_src_addr(), inp)) ||
591 (ip4_addr_ismulticast(ip4_current_src_addr()))) {
592 /* packet source is not valid */
593 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip4_input: packet source is not valid.\n"));
594 /* free (drop) packet pbufs */
595 pbuf_free(p);
596 IP_STATS_INC(ip.drop);
597 MIB2_STATS_INC(mib2.ipinaddrerrors);
598 MIB2_STATS_INC(mib2.ipindiscards);
599 return ERR_OK;
600 }
601 }
602  
603 /* if we're pretending we are everyone for TCP, assume the packet is for source interface if it
604 isn't for a local address */
605 if (netif == NULL && (inp->flags & NETIF_FLAG_PRETEND_TCP) && IPH_PROTO(iphdr) == IP_PROTO_TCP) {
606 netif = inp;
607 }
608  
609 /* packet not for us? */
610 if (netif == NULL) {
611 /* packet not for us, route or discard */
612 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: packet not for us.\n"));
613 #if IP_FORWARD
614 /* non-broadcast packet? */
615 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), inp)) {
616 /* try to forward IP packet on (other) interfaces */
617 ip4_forward(p, (struct ip_hdr *)p->payload, inp);
618 } else
619 #endif /* IP_FORWARD */
620 {
621 IP_STATS_INC(ip.drop);
622 MIB2_STATS_INC(mib2.ipinaddrerrors);
623 MIB2_STATS_INC(mib2.ipindiscards);
624 }
625 pbuf_free(p);
626 return ERR_OK;
627 }
628 /* packet consists of multiple fragments? */
629 if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) {
630 #if IP_REASSEMBLY /* packet fragment reassembly code present? */
631 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",
632 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)));
633 /* reassemble the packet*/
634 p = ip4_reass(p);
635 /* packet not fully reassembled yet? */
636 if (p == NULL) {
637 return ERR_OK;
638 }
639 iphdr = (const struct ip_hdr *)p->payload;
640 #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
641 pbuf_free(p);
642 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
643 lwip_ntohs(IPH_OFFSET(iphdr))));
644 IP_STATS_INC(ip.opterr);
645 IP_STATS_INC(ip.drop);
646 /* unsupported protocol feature */
647 MIB2_STATS_INC(mib2.ipinunknownprotos);
648 return ERR_OK;
649 #endif /* IP_REASSEMBLY */
650 }
651  
652 #if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
653  
654 #if LWIP_IGMP
655 /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
656 if ((iphdr_hlen > IP_HLEN) && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
657 #else
658 if (iphdr_hlen > IP_HLEN) {
659 #endif /* LWIP_IGMP */
660 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
661 pbuf_free(p);
662 IP_STATS_INC(ip.opterr);
663 IP_STATS_INC(ip.drop);
664 /* unsupported protocol feature */
665 MIB2_STATS_INC(mib2.ipinunknownprotos);
666 return ERR_OK;
667 }
668 #endif /* IP_OPTIONS_ALLOWED == 0 */
669  
670 /* send to upper layers */
671 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: \n"));
672 ip4_debug_print(p);
673 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
674  
675 ip_data.current_netif = netif;
676 ip_data.current_input_netif = inp;
677 ip_data.current_ip4_header = iphdr;
678 ip_data.current_ip_header_tot_len = IPH_HL_BYTES(iphdr);
679  
680 #if LWIP_RAW
681 /* raw input did not eat the packet? */
682 if (raw_input(p, inp) == 0)
683 #endif /* LWIP_RAW */
684 {
685 pbuf_remove_header(p, iphdr_hlen); /* Move to payload, no check necessary. */
686  
687 switch (IPH_PROTO(iphdr)) {
688 #if LWIP_UDP
689 case IP_PROTO_UDP:
690 #if LWIP_UDPLITE
691 case IP_PROTO_UDPLITE:
692 #endif /* LWIP_UDPLITE */
693 MIB2_STATS_INC(mib2.ipindelivers);
694 udp_input(p, inp);
695 break;
696 #endif /* LWIP_UDP */
697 #if LWIP_TCP
698 case IP_PROTO_TCP:
699 MIB2_STATS_INC(mib2.ipindelivers);
700 tcp_input(p, inp);
701 break;
702 #endif /* LWIP_TCP */
703 #if LWIP_ICMP
704 case IP_PROTO_ICMP:
705 MIB2_STATS_INC(mib2.ipindelivers);
706 icmp_input(p, inp);
707 break;
708 #endif /* LWIP_ICMP */
709 #if LWIP_IGMP
710 case IP_PROTO_IGMP:
711 igmp_input(p, inp, ip4_current_dest_addr());
712 break;
713 #endif /* LWIP_IGMP */
714 default:
715 #if LWIP_ICMP
716 /* send ICMP destination protocol unreachable unless is was a broadcast */
717 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), netif) &&
718 !ip4_addr_ismulticast(ip4_current_dest_addr())) {
719 pbuf_header_force(p, (s16_t)iphdr_hlen); /* Move to ip header, no check necessary. */
720 icmp_dest_unreach(p, ICMP_DUR_PROTO);
721 }
722 #endif /* LWIP_ICMP */
723 pbuf_free(p);
724  
725 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", (u16_t)IPH_PROTO(iphdr)));
726  
727 IP_STATS_INC(ip.proterr);
728 IP_STATS_INC(ip.drop);
729 MIB2_STATS_INC(mib2.ipinunknownprotos);
730 }
731 }
732  
733 /* @todo: this is not really necessary... */
734 ip_data.current_netif = NULL;
735 ip_data.current_input_netif = NULL;
736 ip_data.current_ip4_header = NULL;
737 ip_data.current_ip_header_tot_len = 0;
738 ip4_addr_set_any(ip4_current_src_addr());
739 ip4_addr_set_any(ip4_current_dest_addr());
740  
741 return ERR_OK;
742 }
743  
744 /**
745 * Sends an IP packet on a network interface. This function constructs
746 * the IP header and calculates the IP header checksum. If the source
747 * IP address is NULL, the IP address of the outgoing network
748 * interface is filled in as source address.
749 * If the destination IP address is LWIP_IP_HDRINCL, p is assumed to already
750 * include an IP header and p->payload points to it instead of the data.
751 *
752 * @param p the packet to send (p->payload points to the data, e.g. next
753 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
754 IP header and p->payload points to that IP header)
755 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
756 * IP address of the netif used to send is used as source address)
757 * @param dest the destination IP address to send the packet to
758 * @param ttl the TTL value to be set in the IP header
759 * @param tos the TOS value to be set in the IP header
760 * @param proto the PROTOCOL to be set in the IP header
761 * @param netif the netif on which to send this packet
762 * @return ERR_OK if the packet was sent OK
763 * ERR_BUF if p doesn't have enough space for IP/LINK headers
764 * returns errors returned by netif->output
765 *
766 * @note ip_id: RFC791 "some host may be able to simply use
767 * unique identifiers independent of destination"
768 */
769 err_t
770 ip4_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
771 u8_t ttl, u8_t tos,
772 u8_t proto, struct netif *netif)
773 {
774 #if IP_OPTIONS_SEND
775 return ip4_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
776 }
777  
778 /**
779 * Same as ip_output_if() but with the possibility to include IP options:
780 *
781 * @ param ip_options pointer to the IP options, copied into the IP header
782 * @ param optlen length of ip_options
783 */
784 err_t
785 ip4_output_if_opt(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
786 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
787 u16_t optlen)
788 {
789 #endif /* IP_OPTIONS_SEND */
790 const ip4_addr_t *src_used = src;
791 if (dest != LWIP_IP_HDRINCL) {
792 if (ip4_addr_isany(src)) {
793 src_used = netif_ip4_addr(netif);
794 }
795 }
796  
797 #if IP_OPTIONS_SEND
798 return ip4_output_if_opt_src(p, src_used, dest, ttl, tos, proto, netif,
799 ip_options, optlen);
800 #else /* IP_OPTIONS_SEND */
801 return ip4_output_if_src(p, src_used, dest, ttl, tos, proto, netif);
802 #endif /* IP_OPTIONS_SEND */
803 }
804  
805 /**
806 * Same as ip_output_if() but 'src' address is not replaced by netif address
807 * when it is 'any'.
808 */
809 err_t
810 ip4_output_if_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
811 u8_t ttl, u8_t tos,
812 u8_t proto, struct netif *netif)
813 {
814 #if IP_OPTIONS_SEND
815 return ip4_output_if_opt_src(p, src, dest, ttl, tos, proto, netif, NULL, 0);
816 }
817  
818 /**
819 * Same as ip_output_if_opt() but 'src' address is not replaced by netif address
820 * when it is 'any'.
821 */
822 err_t
823 ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
824 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
825 u16_t optlen)
826 {
827 #endif /* IP_OPTIONS_SEND */
828 struct ip_hdr *iphdr;
829 ip4_addr_t dest_addr;
830 #if CHECKSUM_GEN_IP_INLINE
831 u32_t chk_sum = 0;
832 #endif /* CHECKSUM_GEN_IP_INLINE */
833  
834 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
835  
836 MIB2_STATS_INC(mib2.ipoutrequests);
837  
838 /* Should the IP header be generated or is it already included in p? */
839 if (dest != LWIP_IP_HDRINCL) {
840 u16_t ip_hlen = IP_HLEN;
841 #if IP_OPTIONS_SEND
842 u16_t optlen_aligned = 0;
843 if (optlen != 0) {
844 #if CHECKSUM_GEN_IP_INLINE
845 int i;
846 #endif /* CHECKSUM_GEN_IP_INLINE */
847 if (optlen > (IP_HLEN_MAX - IP_HLEN)) {
848 /* optlen too long */
849 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: optlen too long\n"));
850 IP_STATS_INC(ip.err);
851 MIB2_STATS_INC(mib2.ipoutdiscards);
852 return ERR_VAL;
853 }
854 /* round up to a multiple of 4 */
855 optlen_aligned = (u16_t)((optlen + 3) & ~3);
856 ip_hlen = (u16_t)(ip_hlen + optlen_aligned);
857 /* First write in the IP options */
858 if (pbuf_add_header(p, optlen_aligned)) {
859 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: not enough room for IP options in pbuf\n"));
860 IP_STATS_INC(ip.err);
861 MIB2_STATS_INC(mib2.ipoutdiscards);
862 return ERR_BUF;
863 }
864 MEMCPY(p->payload, ip_options, optlen);
865 if (optlen < optlen_aligned) {
866 /* zero the remaining bytes */
867 memset(((char *)p->payload) + optlen, 0, (size_t)(optlen_aligned - optlen));
868 }
869 #if CHECKSUM_GEN_IP_INLINE
870 for (i = 0; i < optlen_aligned / 2; i++) {
871 chk_sum += ((u16_t *)p->payload)[i];
872 }
873 #endif /* CHECKSUM_GEN_IP_INLINE */
874 }
875 #endif /* IP_OPTIONS_SEND */
876 /* generate IP header */
877 if (pbuf_add_header(p, IP_HLEN)) {
878 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: not enough room for IP header in pbuf\n"));
879  
880 IP_STATS_INC(ip.err);
881 MIB2_STATS_INC(mib2.ipoutdiscards);
882 return ERR_BUF;
883 }
884  
885 iphdr = (struct ip_hdr *)p->payload;
886 LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
887 (p->len >= sizeof(struct ip_hdr)));
888  
889 IPH_TTL_SET(iphdr, ttl);
890 IPH_PROTO_SET(iphdr, proto);
891 #if CHECKSUM_GEN_IP_INLINE
892 chk_sum += PP_NTOHS(proto | (ttl << 8));
893 #endif /* CHECKSUM_GEN_IP_INLINE */
894  
895 /* dest cannot be NULL here */
896 ip4_addr_copy(iphdr->dest, *dest);
897 #if CHECKSUM_GEN_IP_INLINE
898 chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
899 chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
900 #endif /* CHECKSUM_GEN_IP_INLINE */
901  
902 IPH_VHL_SET(iphdr, 4, ip_hlen / 4);
903 IPH_TOS_SET(iphdr, tos);
904 #if CHECKSUM_GEN_IP_INLINE
905 chk_sum += PP_NTOHS(tos | (iphdr->_v_hl << 8));
906 #endif /* CHECKSUM_GEN_IP_INLINE */
907 IPH_LEN_SET(iphdr, lwip_htons(p->tot_len));
908 #if CHECKSUM_GEN_IP_INLINE
909 chk_sum += iphdr->_len;
910 #endif /* CHECKSUM_GEN_IP_INLINE */
911 IPH_OFFSET_SET(iphdr, 0);
912 IPH_ID_SET(iphdr, lwip_htons(ip_id));
913 #if CHECKSUM_GEN_IP_INLINE
914 chk_sum += iphdr->_id;
915 #endif /* CHECKSUM_GEN_IP_INLINE */
916 ++ip_id;
917  
918 if (src == NULL) {
919 ip4_addr_copy(iphdr->src, *IP4_ADDR_ANY4);
920 } else {
921 /* src cannot be NULL here */
922 ip4_addr_copy(iphdr->src, *src);
923 }
924  
925 #if CHECKSUM_GEN_IP_INLINE
926 chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
927 chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
928 chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
929 chk_sum = (chk_sum >> 16) + chk_sum;
930 chk_sum = ~chk_sum;
931 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
932 iphdr->_chksum = (u16_t)chk_sum; /* network order */
933 }
934 #if LWIP_CHECKSUM_CTRL_PER_NETIF
935 else {
936 IPH_CHKSUM_SET(iphdr, 0);
937 }
938 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF*/
939 #else /* CHECKSUM_GEN_IP_INLINE */
940 IPH_CHKSUM_SET(iphdr, 0);
941 #if CHECKSUM_GEN_IP
942 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
943 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
944 }
945 #endif /* CHECKSUM_GEN_IP */
946 #endif /* CHECKSUM_GEN_IP_INLINE */
947 } else {
948 /* IP header already included in p */
949 if (p->len < IP_HLEN) {
950 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: LWIP_IP_HDRINCL but pbuf is too short\n"));
951 IP_STATS_INC(ip.err);
952 MIB2_STATS_INC(mib2.ipoutdiscards);
953 return ERR_BUF;
954 }
955 iphdr = (struct ip_hdr *)p->payload;
956 ip4_addr_copy(dest_addr, iphdr->dest);
957 dest = &dest_addr;
958 }
959  
960 IP_STATS_INC(ip.xmit);
961  
962 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
963 ip4_debug_print(p);
964  
965 #if ENABLE_LOOPBACK
966 if (ip4_addr_cmp(dest, netif_ip4_addr(netif))
967 #if !LWIP_HAVE_LOOPIF
968 || ip4_addr_isloopback(dest)
969 #endif /* !LWIP_HAVE_LOOPIF */
970 ) {
971 /* Packet to self, enqueue it for loopback */
972 LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
973 return netif_loop_output(netif, p);
974 }
975 #if LWIP_MULTICAST_TX_OPTIONS
976 if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
977 netif_loop_output(netif, p);
978 }
979 #endif /* LWIP_MULTICAST_TX_OPTIONS */
980 #endif /* ENABLE_LOOPBACK */
981 #if IP_FRAG
982 /* don't fragment if interface has mtu set to 0 [loopif] */
983 if (netif->mtu && (p->tot_len > netif->mtu)) {
984 return ip4_frag(p, netif, dest);
985 }
986 #endif /* IP_FRAG */
987  
988 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));
989 return netif->output(netif, p, dest);
990 }
991  
992 /**
993 * Simple interface to ip_output_if. It finds the outgoing network
994 * interface and calls upon ip_output_if to do the actual work.
995 *
996 * @param p the packet to send (p->payload points to the data, e.g. next
997 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
998 IP header and p->payload points to that IP header)
999 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
1000 * IP address of the netif used to send is used as source address)
1001 * @param dest the destination IP address to send the packet to
1002 * @param ttl the TTL value to be set in the IP header
1003 * @param tos the TOS value to be set in the IP header
1004 * @param proto the PROTOCOL to be set in the IP header
1005 *
1006 * @return ERR_RTE if no route is found
1007 * see ip_output_if() for more return values
1008 */
1009 err_t
1010 ip4_output(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
1011 u8_t ttl, u8_t tos, u8_t proto)
1012 {
1013 struct netif *netif;
1014  
1015 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
1016  
1017 if ((netif = ip4_route_src(src, dest)) == NULL) {
1018 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1019 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
1020 IP_STATS_INC(ip.rterr);
1021 return ERR_RTE;
1022 }
1023  
1024 return ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1025 }
1026  
1027 #if LWIP_NETIF_USE_HINTS
1028 /** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
1029 * before calling ip_output_if.
1030 *
1031 * @param p the packet to send (p->payload points to the data, e.g. next
1032 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
1033 IP header and p->payload points to that IP header)
1034 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
1035 * IP address of the netif used to send is used as source address)
1036 * @param dest the destination IP address to send the packet to
1037 * @param ttl the TTL value to be set in the IP header
1038 * @param tos the TOS value to be set in the IP header
1039 * @param proto the PROTOCOL to be set in the IP header
1040 * @param netif_hint netif output hint pointer set to netif->hint before
1041 * calling ip_output_if()
1042 *
1043 * @return ERR_RTE if no route is found
1044 * see ip_output_if() for more return values
1045 */
1046 err_t
1047 ip4_output_hinted(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
1048 u8_t ttl, u8_t tos, u8_t proto, struct netif_hint *netif_hint)
1049 {
1050 struct netif *netif;
1051 err_t err;
1052  
1053 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
1054  
1055 if ((netif = ip4_route_src(src, dest)) == NULL) {
1056 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1057 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
1058 IP_STATS_INC(ip.rterr);
1059 return ERR_RTE;
1060 }
1061  
1062 NETIF_SET_HINTS(netif, netif_hint);
1063 err = ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1064 NETIF_RESET_HINTS(netif);
1065  
1066 return err;
1067 }
1068 #endif /* LWIP_NETIF_USE_HINTS*/
1069  
1070 #if IP_DEBUG
1071 /* Print an IP header by using LWIP_DEBUGF
1072 * @param p an IP packet, p->payload pointing to the IP header
1073 */
1074 void
1075 ip4_debug_print(struct pbuf *p)
1076 {
1077 struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
1078  
1079 LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
1080 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1081 LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n",
1082 (u16_t)IPH_V(iphdr),
1083 (u16_t)IPH_HL(iphdr),
1084 (u16_t)IPH_TOS(iphdr),
1085 lwip_ntohs(IPH_LEN(iphdr))));
1086 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1087 LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n",
1088 lwip_ntohs(IPH_ID(iphdr)),
1089 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 15 & 1),
1090 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 14 & 1),
1091 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 13 & 1),
1092 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)));
1093 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1094 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n",
1095 (u16_t)IPH_TTL(iphdr),
1096 (u16_t)IPH_PROTO(iphdr),
1097 lwip_ntohs(IPH_CHKSUM(iphdr))));
1098 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1099 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n",
1100 ip4_addr1_16(&iphdr->src),
1101 ip4_addr2_16(&iphdr->src),
1102 ip4_addr3_16(&iphdr->src),
1103 ip4_addr4_16(&iphdr->src)));
1104 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1105 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n",
1106 ip4_addr1_16(&iphdr->dest),
1107 ip4_addr2_16(&iphdr->dest),
1108 ip4_addr3_16(&iphdr->dest),
1109 ip4_addr4_16(&iphdr->dest)));
1110 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1111 }
1112 #endif /* IP_DEBUG */
1113  
1114 #endif /* LWIP_IPV4 */