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/priv/raw_priv.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
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 the parameters.
127 */
128 struct netif *
ip4_route_src(const ip4_addr_t * src,const ip4_addr_t * dest)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 *
ip4_route(const ip4_addr_t * dest)152 ip4_route(const ip4_addr_t *dest)
153 {
154 #if !LWIP_SINGLE_NETIF
155 struct netif *netif;
156
157 LWIP_ASSERT_CORE_LOCKED();
158
159 #if LWIP_MULTICAST_TX_OPTIONS
160 /* Use administratively selected interface for multicast by default */
161 if (ip4_addr_ismulticast(dest) && ip4_default_multicast_netif) {
162 return ip4_default_multicast_netif;
163 }
164 #endif /* LWIP_MULTICAST_TX_OPTIONS */
165
166 /* bug #54569: in case LWIP_SINGLE_NETIF=1 and LWIP_DEBUGF() disabled, the following loop is optimized away */
167 LWIP_UNUSED_ARG(dest);
168
169 /* iterate through netifs */
170 NETIF_FOREACH(netif) {
171 /* is the netif up, does it have a link and a valid address? */
172 if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
173 /* network mask matches? */
174 if (ip4_addr_netcmp(dest, netif_ip4_addr(netif), netif_ip4_netmask(netif))) {
175 /* return netif on which to forward IP packet */
176 return netif;
177 }
178 /* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */
179 if (((netif->flags & NETIF_FLAG_BROADCAST) == 0) && ip4_addr_cmp(dest, netif_ip4_gw(netif))) {
180 /* return netif on which to forward IP packet */
181 return netif;
182 }
183 }
184 }
185
186 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
187 /* loopif is disabled, looopback traffic is passed through any netif */
188 if (ip4_addr_isloopback(dest)) {
189 /* don't check for link on loopback traffic */
190 if (netif_default != NULL && netif_is_up(netif_default)) {
191 return netif_default;
192 }
193 /* default netif is not up, just use any netif for loopback traffic */
194 NETIF_FOREACH(netif) {
195 if (netif_is_up(netif)) {
196 return netif;
197 }
198 }
199 return NULL;
200 }
201 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
202
203 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
204 netif = LWIP_HOOK_IP4_ROUTE_SRC(NULL, dest);
205 if (netif != NULL) {
206 return netif;
207 }
208 #elif defined(LWIP_HOOK_IP4_ROUTE)
209 netif = LWIP_HOOK_IP4_ROUTE(dest);
210 if (netif != NULL) {
211 return netif;
212 }
213 #endif
214 #endif /* !LWIP_SINGLE_NETIF */
215
216 if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default) ||
217 ip4_addr_isany_val(*netif_ip4_addr(netif_default)) || ip4_addr_isloopback(dest)) {
218 /* No matching netif found and default netif is not usable.
219 If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
220 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
221 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
222 IP_STATS_INC(ip.rterr);
223 MIB2_STATS_INC(mib2.ipoutnoroutes);
224 return NULL;
225 }
226
227 return netif_default;
228 }
229
230 #if IP_FORWARD
231 /**
232 * Determine whether an IP address is in a reserved set of addresses
233 * that may not be forwarded, or whether datagrams to that destination
234 * may be forwarded.
235 * @param p the packet to forward
236 * @return 1: can forward 0: discard
237 */
238 static int
ip4_canforward(struct pbuf * p)239 ip4_canforward(struct pbuf *p)
240 {
241 u32_t addr = lwip_htonl(ip4_addr_get_u32(ip4_current_dest_addr()));
242
243 #ifdef LWIP_HOOK_IP4_CANFORWARD
244 int ret = LWIP_HOOK_IP4_CANFORWARD(p, addr);
245 if (ret >= 0) {
246 return ret;
247 }
248 #endif /* LWIP_HOOK_IP4_CANFORWARD */
249
250 if (p->flags & PBUF_FLAG_LLBCAST) {
251 /* don't route link-layer broadcasts */
252 return 0;
253 }
254 if ((p->flags & PBUF_FLAG_LLMCAST) || IP_MULTICAST(addr)) {
255 /* don't route link-layer multicasts (use LWIP_HOOK_IP4_CANFORWARD instead) */
256 return 0;
257 }
258 if (IP_EXPERIMENTAL(addr)) {
259 return 0;
260 }
261 if (IP_CLASSA(addr)) {
262 u32_t net = addr & IP_CLASSA_NET;
263 if ((net == 0) || (net == ((u32_t)IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
264 /* don't route loopback packets */
265 return 0;
266 }
267 }
268 return 1;
269 }
270
271 /**
272 * Forwards an IP packet. It finds an appropriate route for the
273 * packet, decrements the TTL value of the packet, adjusts the
274 * checksum and outputs the packet on the appropriate interface.
275 *
276 * @param p the packet to forward (p->payload points to IP header)
277 * @param iphdr the IP header of the input packet
278 * @param inp the netif on which this packet was received
279 */
280 static void
ip4_forward(struct pbuf * p,struct ip_hdr * iphdr,struct netif * inp)281 ip4_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
282 {
283 struct netif *netif;
284
285 PERF_START;
286 LWIP_UNUSED_ARG(inp);
287
288 if (!ip4_canforward(p)) {
289 goto return_noroute;
290 }
291
292 /* RFC3927 2.7: do not forward link-local addresses */
293 if (ip4_addr_islinklocal(ip4_current_dest_addr())) {
294 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\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 goto return_noroute;
298 }
299
300 /* Find network interface where to forward this IP packet to. */
301 netif = ip4_route_src(ip4_current_src_addr(), ip4_current_dest_addr());
302 if (netif == NULL) {
303 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
304 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
305 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
306 /* @todo: send ICMP_DUR_NET? */
307 goto return_noroute;
308 }
309 #if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
310 /* Do not forward packets onto the same network interface on which
311 * they arrived. */
312 if (netif == inp) {
313 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not bouncing packets back on incoming interface.\n"));
314 goto return_noroute;
315 }
316 #endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
317
318 /* decrement TTL */
319 IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
320 /* send ICMP if TTL == 0 */
321 if (IPH_TTL(iphdr) == 0) {
322 MIB2_STATS_INC(mib2.ipinhdrerrors);
323 #if LWIP_ICMP
324 /* Don't send ICMP messages in response to ICMP messages */
325 if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
326 icmp_time_exceeded(p, ICMP_TE_TTL);
327 }
328 #endif /* LWIP_ICMP */
329 return;
330 }
331
332 /* Incrementally update the IP checksum. */
333 if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
334 IPH_CHKSUM_SET(iphdr, (u16_t)(IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1));
335 } else {
336 IPH_CHKSUM_SET(iphdr, (u16_t)(IPH_CHKSUM(iphdr) + PP_HTONS(0x100)));
337 }
338
339 LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
340 ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
341 ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
342
343 IP_STATS_INC(ip.fw);
344 MIB2_STATS_INC(mib2.ipforwdatagrams);
345 IP_STATS_INC(ip.xmit);
346
347 PERF_STOP("ip4_forward");
348 /* don't fragment if interface has mtu set to 0 [loopif] */
349 if (netif->mtu && (p->tot_len > netif->mtu)) {
350 if ((IPH_OFFSET(iphdr) & PP_NTOHS(IP_DF)) == 0) {
351 #if IP_FRAG
352 ip4_frag(p, netif, ip4_current_dest_addr());
353 #else /* IP_FRAG */
354 /* @todo: send ICMP Destination Unreachable code 13 "Communication administratively prohibited"? */
355 #endif /* IP_FRAG */
356 } else {
357 #if LWIP_ICMP
358 /* send ICMP Destination Unreachable code 4: "Fragmentation Needed and DF Set" */
359 icmp_dest_unreach(p, ICMP_DUR_FRAG);
360 #endif /* LWIP_ICMP */
361 }
362 return;
363 }
364 /* transmit pbuf on chosen interface */
365 netif->output(netif, p, ip4_current_dest_addr());
366 return;
367 return_noroute:
368 MIB2_STATS_INC(mib2.ipoutnoroutes);
369 }
370 #endif /* IP_FORWARD */
371
372 /** Return true if the current input packet should be accepted on this netif */
373 static int
ip4_input_accept(struct netif * netif)374 ip4_input_accept(struct netif *netif)
375 {
376 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",
377 ip4_addr_get_u32(ip4_current_dest_addr()), ip4_addr_get_u32(netif_ip4_addr(netif)),
378 ip4_addr_get_u32(ip4_current_dest_addr()) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
379 ip4_addr_get_u32(netif_ip4_addr(netif)) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
380 ip4_addr_get_u32(ip4_current_dest_addr()) & ~ip4_addr_get_u32(netif_ip4_netmask(netif))));
381
382 /* interface is up and configured? */
383 if ((netif_is_up(netif)) && (!ip4_addr_isany_val(*netif_ip4_addr(netif)))) {
384 /* unicast to this interface address? */
385 if (ip4_addr_cmp(ip4_current_dest_addr(), netif_ip4_addr(netif)) ||
386 /* or broadcast on this interface network address? */
387 ip4_addr_isbroadcast(ip4_current_dest_addr(), netif)
388 #if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
389 || (ip4_addr_get_u32(ip4_current_dest_addr()) == PP_HTONL(IPADDR_LOOPBACK))
390 #endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
391 ) {
392 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: packet accepted on interface %c%c\n",
393 netif->name[0], netif->name[1]));
394 /* accept on this netif */
395 return 1;
396 }
397 #if LWIP_AUTOIP
398 /* connections to link-local addresses must persist after changing
399 the netif's address (RFC3927 ch. 1.9) */
400 if (autoip_accept_packet(netif, ip4_current_dest_addr())) {
401 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: LLA packet accepted on interface %c%c\n",
402 netif->name[0], netif->name[1]));
403 /* accept on this netif */
404 return 1;
405 }
406 #endif /* LWIP_AUTOIP */
407 }
408 return 0;
409 }
410
411 /**
412 * This function is called by the network interface device driver when
413 * an IP packet is received. The function does the basic checks of the
414 * IP header such as packet size being at least larger than the header
415 * size etc. If the packet was not destined for us, the packet is
416 * forwarded (using ip_forward). The IP checksum is always checked.
417 *
418 * Finally, the packet is sent to the upper layer protocol input function.
419 *
420 * @param p the received IP packet (p->payload points to IP header)
421 * @param inp the netif on which this packet was received
422 * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
423 * processed, but currently always returns ERR_OK)
424 */
425 err_t
ip4_input(struct pbuf * p,struct netif * inp)426 ip4_input(struct pbuf *p, struct netif *inp)
427 {
428 const struct ip_hdr *iphdr;
429 struct netif *netif;
430 u16_t iphdr_hlen;
431 u16_t iphdr_len;
432 #if IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP
433 int check_ip_src = 1;
434 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP */
435 #if LWIP_RAW
436 raw_input_state_t raw_status;
437 #endif /* LWIP_RAW */
438
439 LWIP_ASSERT_CORE_LOCKED();
440
441 IP_STATS_INC(ip.recv);
442 MIB2_STATS_INC(mib2.ipinreceives);
443
444 /* identify the IP header */
445 iphdr = (struct ip_hdr *)p->payload;
446 if (IPH_V(iphdr) != 4) {
447 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", (u16_t)IPH_V(iphdr)));
448 ip4_debug_print(p);
449 pbuf_free(p);
450 IP_STATS_INC(ip.err);
451 IP_STATS_INC(ip.drop);
452 MIB2_STATS_INC(mib2.ipinhdrerrors);
453 return ERR_OK;
454 }
455
456 #ifdef LWIP_HOOK_IP4_INPUT
457 if (LWIP_HOOK_IP4_INPUT(p, inp)) {
458 /* the packet has been eaten */
459 return ERR_OK;
460 }
461 #endif
462
463 /* obtain IP header length in bytes */
464 iphdr_hlen = IPH_HL_BYTES(iphdr);
465 /* obtain ip length in bytes */
466 iphdr_len = lwip_ntohs(IPH_LEN(iphdr));
467
468 /* Trim pbuf. This is especially required for packets < 60 bytes. */
469 if (iphdr_len < p->tot_len) {
470 pbuf_realloc(p, iphdr_len);
471 }
472
473 /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
474 if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len) || (iphdr_hlen < IP_HLEN)) {
475 if (iphdr_hlen < IP_HLEN) {
476 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
477 ("ip4_input: short IP header (%"U16_F" bytes) received, IP packet dropped\n", iphdr_hlen));
478 }
479 if (iphdr_hlen > p->len) {
480 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
481 ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
482 iphdr_hlen, p->len));
483 }
484 if (iphdr_len > p->tot_len) {
485 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
486 ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
487 iphdr_len, p->tot_len));
488 }
489 /* free (drop) packet pbufs */
490 pbuf_free(p);
491 IP_STATS_INC(ip.lenerr);
492 IP_STATS_INC(ip.drop);
493 MIB2_STATS_INC(mib2.ipindiscards);
494 return ERR_OK;
495 }
496
497 /* verify checksum */
498 #if CHECKSUM_CHECK_IP
499 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_IP) {
500 if (inet_chksum(iphdr, iphdr_hlen) != 0) {
501
502 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
503 ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
504 ip4_debug_print(p);
505 pbuf_free(p);
506 IP_STATS_INC(ip.chkerr);
507 IP_STATS_INC(ip.drop);
508 MIB2_STATS_INC(mib2.ipinhdrerrors);
509 return ERR_OK;
510 }
511 }
512 #endif
513
514 /* copy IP addresses to aligned ip_addr_t */
515 ip_addr_copy_from_ip4(ip_data.current_iphdr_dest, iphdr->dest);
516 ip_addr_copy_from_ip4(ip_data.current_iphdr_src, iphdr->src);
517
518 /* match packet against an interface, i.e. is this packet for us? */
519 if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
520 #if LWIP_IGMP
521 if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ip4_current_dest_addr()))) {
522 /* IGMP snooping switches need 0.0.0.0 to be allowed as source address (RFC 4541) */
523 ip4_addr_t allsystems;
524 IP4_ADDR(&allsystems, 224, 0, 0, 1);
525 if (ip4_addr_cmp(ip4_current_dest_addr(), &allsystems) &&
526 ip4_addr_isany(ip4_current_src_addr())) {
527 check_ip_src = 0;
528 }
529 netif = inp;
530 } else {
531 netif = NULL;
532 }
533 #else /* LWIP_IGMP */
534 if ((netif_is_up(inp)) && (!ip4_addr_isany_val(*netif_ip4_addr(inp)))) {
535 netif = inp;
536 } else {
537 netif = NULL;
538 }
539 #endif /* LWIP_IGMP */
540 } else {
541 /* start trying with inp. if that's not acceptable, start walking the
542 list of configured netifs. */
543 if (ip4_input_accept(inp)) {
544 netif = inp;
545 } else {
546 netif = NULL;
547 #if !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF
548 /* Packets sent to the loopback address must not be accepted on an
549 * interface that does not have the loopback address assigned to it,
550 * unless a non-loopback interface is used for loopback traffic. */
551 if (!ip4_addr_isloopback(ip4_current_dest_addr()))
552 #endif /* !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF */
553 {
554 #if !LWIP_SINGLE_NETIF
555 NETIF_FOREACH(netif) {
556 if (netif == inp) {
557 /* we checked that before already */
558 continue;
559 }
560 if (ip4_input_accept(netif)) {
561 break;
562 }
563 }
564 #endif /* !LWIP_SINGLE_NETIF */
565 }
566 }
567 }
568
569 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
570 /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
571 * using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
572 * According to RFC 1542 section 3.1.1, referred by RFC 2131).
573 *
574 * If you want to accept private broadcast communication while a netif is down,
575 * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
576 *
577 * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
578 */
579 if (netif == NULL) {
580 /* remote port is DHCP server? */
581 if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
582 const struct udp_hdr *udphdr = (const struct udp_hdr *)((const u8_t *)iphdr + iphdr_hlen);
583 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: UDP packet to DHCP client port %"U16_F"\n",
584 lwip_ntohs(udphdr->dest)));
585 if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
586 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: DHCP packet accepted.\n"));
587 netif = inp;
588 check_ip_src = 0;
589 }
590 }
591 }
592 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
593
594 /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
595 #if LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING
596 if (check_ip_src
597 #if IP_ACCEPT_LINK_LAYER_ADDRESSING
598 /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
599 && !ip4_addr_isany_val(*ip4_current_src_addr())
600 #endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
601 )
602 #endif /* LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING */
603 {
604 if ((ip4_addr_isbroadcast(ip4_current_src_addr(), inp)) ||
605 (ip4_addr_ismulticast(ip4_current_src_addr()))) {
606 /* packet source is not valid */
607 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip4_input: packet source is not valid.\n"));
608 /* free (drop) packet pbufs */
609 pbuf_free(p);
610 IP_STATS_INC(ip.drop);
611 MIB2_STATS_INC(mib2.ipinaddrerrors);
612 MIB2_STATS_INC(mib2.ipindiscards);
613 return ERR_OK;
614 }
615 }
616
617 /* packet not for us? */
618 if (netif == NULL) {
619 /* packet not for us, route or discard */
620 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: packet not for us.\n"));
621 #if IP_FORWARD
622 /* non-broadcast packet? */
623 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), inp)) {
624 /* try to forward IP packet on (other) interfaces */
625 ip4_forward(p, (struct ip_hdr *)p->payload, inp);
626 } else
627 #endif /* IP_FORWARD */
628 {
629 IP_STATS_INC(ip.drop);
630 MIB2_STATS_INC(mib2.ipinaddrerrors);
631 MIB2_STATS_INC(mib2.ipindiscards);
632 }
633 pbuf_free(p);
634 return ERR_OK;
635 }
636 /* packet consists of multiple fragments? */
637 if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) {
638 #if IP_REASSEMBLY /* packet fragment reassembly code present? */
639 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",
640 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)));
641 /* reassemble the packet*/
642 p = ip4_reass(p);
643 /* packet not fully reassembled yet? */
644 if (p == NULL) {
645 return ERR_OK;
646 }
647 iphdr = (const struct ip_hdr *)p->payload;
648 #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
649 pbuf_free(p);
650 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
651 lwip_ntohs(IPH_OFFSET(iphdr))));
652 IP_STATS_INC(ip.opterr);
653 IP_STATS_INC(ip.drop);
654 /* unsupported protocol feature */
655 MIB2_STATS_INC(mib2.ipinunknownprotos);
656 return ERR_OK;
657 #endif /* IP_REASSEMBLY */
658 }
659
660 #if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
661
662 #if LWIP_IGMP
663 /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
664 if ((iphdr_hlen > IP_HLEN) && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
665 #else
666 if (iphdr_hlen > IP_HLEN) {
667 #endif /* LWIP_IGMP */
668 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
669 pbuf_free(p);
670 IP_STATS_INC(ip.opterr);
671 IP_STATS_INC(ip.drop);
672 /* unsupported protocol feature */
673 MIB2_STATS_INC(mib2.ipinunknownprotos);
674 return ERR_OK;
675 }
676 #endif /* IP_OPTIONS_ALLOWED == 0 */
677
678 /* send to upper layers */
679 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: \n"));
680 ip4_debug_print(p);
681 LWIP_DEBUGF(IP_DEBUG, ("ip4_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
682
683 ip_data.current_netif = netif;
684 ip_data.current_input_netif = inp;
685 ip_data.current_ip4_header = iphdr;
686 ip_data.current_ip_header_tot_len = IPH_HL_BYTES(iphdr);
687
688 #if LWIP_RAW
689 /* raw input did not eat the packet? */
690 raw_status = raw_input(p, inp);
691 if (raw_status != RAW_INPUT_EATEN)
692 #endif /* LWIP_RAW */
693 {
694 pbuf_remove_header(p, iphdr_hlen); /* Move to payload, no check necessary. */
695
696 switch (IPH_PROTO(iphdr)) {
697 #if LWIP_UDP
698 case IP_PROTO_UDP:
699 #if LWIP_UDPLITE
700 case IP_PROTO_UDPLITE:
701 #endif /* LWIP_UDPLITE */
702 MIB2_STATS_INC(mib2.ipindelivers);
703 udp_input(p, inp);
704 break;
705 #endif /* LWIP_UDP */
706 #if LWIP_TCP
707 case IP_PROTO_TCP:
708 MIB2_STATS_INC(mib2.ipindelivers);
709 tcp_input(p, inp);
710 break;
711 #endif /* LWIP_TCP */
712 #if LWIP_ICMP
713 case IP_PROTO_ICMP:
714 MIB2_STATS_INC(mib2.ipindelivers);
715 icmp_input(p, inp);
716 break;
717 #endif /* LWIP_ICMP */
718 #if LWIP_IGMP
719 case IP_PROTO_IGMP:
720 igmp_input(p, inp, ip4_current_dest_addr());
721 break;
722 #endif /* LWIP_IGMP */
723 default:
724 #if LWIP_RAW
725 if (raw_status == RAW_INPUT_DELIVERED) {
726 MIB2_STATS_INC(mib2.ipindelivers);
727 } else
728 #endif /* LWIP_RAW */
729 {
730 #if LWIP_ICMP
731 /* send ICMP destination protocol unreachable unless is was a broadcast */
732 if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), netif) &&
733 !ip4_addr_ismulticast(ip4_current_dest_addr())) {
734 pbuf_header_force(p, (s16_t)iphdr_hlen); /* Move to ip header, no check necessary. */
735 icmp_dest_unreach(p, ICMP_DUR_PROTO);
736 }
737 #endif /* LWIP_ICMP */
738
739 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", (u16_t)IPH_PROTO(iphdr)));
740
741 IP_STATS_INC(ip.proterr);
742 IP_STATS_INC(ip.drop);
743 MIB2_STATS_INC(mib2.ipinunknownprotos);
744 }
745 pbuf_free(p);
746 break;
747 }
748 }
749
750 /* @todo: this is not really necessary... */
751 ip_data.current_netif = NULL;
752 ip_data.current_input_netif = NULL;
753 ip_data.current_ip4_header = NULL;
754 ip_data.current_ip_header_tot_len = 0;
755 ip4_addr_set_any(ip4_current_src_addr());
756 ip4_addr_set_any(ip4_current_dest_addr());
757
758 return ERR_OK;
759 }
760
761 /**
762 * Sends an IP packet on a network interface. This function constructs
763 * the IP header and calculates the IP header checksum. If the source
764 * IP address is NULL, the IP address of the outgoing network
765 * interface is filled in as source address.
766 * If the destination IP address is LWIP_IP_HDRINCL, p is assumed to already
767 * include an IP header and p->payload points to it instead of the data.
768 *
769 * @param p the packet to send (p->payload points to the data, e.g. next
770 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
771 IP header and p->payload points to that IP header)
772 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
773 * IP address of the netif used to send is used as source address)
774 * @param dest the destination IP address to send the packet to
775 * @param ttl the TTL value to be set in the IP header
776 * @param tos the TOS value to be set in the IP header
777 * @param proto the PROTOCOL to be set in the IP header
778 * @param netif the netif on which to send this packet
779 * @return ERR_OK if the packet was sent OK
780 * ERR_BUF if p doesn't have enough space for IP/LINK headers
781 * returns errors returned by netif->output
782 *
783 * @note ip_id: RFC791 "some host may be able to simply use
784 * unique identifiers independent of destination"
785 */
786 err_t
787 ip4_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
788 u8_t ttl, u8_t tos,
789 u8_t proto, struct netif *netif)
790 {
791 #if IP_OPTIONS_SEND
792 return ip4_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
793 }
794
795 /**
796 * Same as ip_output_if() but with the possibility to include IP options:
797 *
798 * @ param ip_options pointer to the IP options, copied into the IP header
799 * @ param optlen length of ip_options
800 */
801 err_t
802 ip4_output_if_opt(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
803 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
804 u16_t optlen)
805 {
806 #endif /* IP_OPTIONS_SEND */
807 const ip4_addr_t *src_used = src;
808 if (dest != LWIP_IP_HDRINCL) {
809 if (ip4_addr_isany(src)) {
810 src_used = netif_ip4_addr(netif);
811 }
812 }
813
814 #if IP_OPTIONS_SEND
815 return ip4_output_if_opt_src(p, src_used, dest, ttl, tos, proto, netif,
816 ip_options, optlen);
817 #else /* IP_OPTIONS_SEND */
818 return ip4_output_if_src(p, src_used, dest, ttl, tos, proto, netif);
819 #endif /* IP_OPTIONS_SEND */
820 }
821
822 /**
823 * Same as ip_output_if() but 'src' address is not replaced by netif address
824 * when it is 'any'.
825 */
826 err_t
827 ip4_output_if_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
828 u8_t ttl, u8_t tos,
829 u8_t proto, struct netif *netif)
830 {
831 #if IP_OPTIONS_SEND
832 return ip4_output_if_opt_src(p, src, dest, ttl, tos, proto, netif, NULL, 0);
833 }
834
835 /**
836 * Same as ip_output_if_opt() but 'src' address is not replaced by netif address
837 * when it is 'any'.
838 */
839 err_t
840 ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
841 u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
842 u16_t optlen)
843 {
844 #endif /* IP_OPTIONS_SEND */
845 struct ip_hdr *iphdr;
846 ip4_addr_t dest_addr;
847 #if CHECKSUM_GEN_IP_INLINE
848 u32_t chk_sum = 0;
849 #endif /* CHECKSUM_GEN_IP_INLINE */
850
851 LWIP_ASSERT_CORE_LOCKED();
852 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
853
854 MIB2_STATS_INC(mib2.ipoutrequests);
855
856 /* Should the IP header be generated or is it already included in p? */
857 if (dest != LWIP_IP_HDRINCL) {
858 u16_t ip_hlen = IP_HLEN;
859 #if IP_OPTIONS_SEND
860 u16_t optlen_aligned = 0;
861 if (optlen != 0) {
862 #if CHECKSUM_GEN_IP_INLINE
863 int i;
864 #endif /* CHECKSUM_GEN_IP_INLINE */
865 if (optlen > (IP_HLEN_MAX - IP_HLEN)) {
866 /* optlen too long */
867 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: optlen too long\n"));
868 IP_STATS_INC(ip.err);
869 MIB2_STATS_INC(mib2.ipoutdiscards);
870 return ERR_VAL;
871 }
872 /* round up to a multiple of 4 */
873 optlen_aligned = (u16_t)((optlen + 3) & ~3);
874 ip_hlen = (u16_t)(ip_hlen + optlen_aligned);
875 /* First write in the IP options */
876 if (pbuf_add_header(p, optlen_aligned)) {
877 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: not enough room for IP options in pbuf\n"));
878 IP_STATS_INC(ip.err);
879 MIB2_STATS_INC(mib2.ipoutdiscards);
880 return ERR_BUF;
881 }
882 MEMCPY(p->payload, ip_options, optlen);
883 if (optlen < optlen_aligned) {
884 /* zero the remaining bytes */
885 memset(((char *)p->payload) + optlen, 0, (size_t)(optlen_aligned - optlen));
886 }
887 #if CHECKSUM_GEN_IP_INLINE
888 for (i = 0; i < optlen_aligned / 2; i++) {
889 chk_sum += ((u16_t *)p->payload)[i];
890 }
891 #endif /* CHECKSUM_GEN_IP_INLINE */
892 }
893 #endif /* IP_OPTIONS_SEND */
894 /* generate IP header */
895 if (pbuf_add_header(p, IP_HLEN)) {
896 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: not enough room for IP header in pbuf\n"));
897
898 IP_STATS_INC(ip.err);
899 MIB2_STATS_INC(mib2.ipoutdiscards);
900 return ERR_BUF;
901 }
902
903 iphdr = (struct ip_hdr *)p->payload;
904 LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
905 (p->len >= sizeof(struct ip_hdr)));
906
907 IPH_TTL_SET(iphdr, ttl);
908 IPH_PROTO_SET(iphdr, proto);
909 #if CHECKSUM_GEN_IP_INLINE
910 chk_sum += PP_NTOHS(proto | (ttl << 8));
911 #endif /* CHECKSUM_GEN_IP_INLINE */
912
913 /* dest cannot be NULL here */
914 ip4_addr_copy(iphdr->dest, *dest);
915 #if CHECKSUM_GEN_IP_INLINE
916 chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
917 chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
918 #endif /* CHECKSUM_GEN_IP_INLINE */
919
920 IPH_VHL_SET(iphdr, 4, ip_hlen / 4);
921 IPH_TOS_SET(iphdr, tos);
922 #if CHECKSUM_GEN_IP_INLINE
923 chk_sum += PP_NTOHS(tos | (iphdr->_v_hl << 8));
924 #endif /* CHECKSUM_GEN_IP_INLINE */
925 IPH_LEN_SET(iphdr, lwip_htons(p->tot_len));
926 #if CHECKSUM_GEN_IP_INLINE
927 chk_sum += iphdr->_len;
928 #endif /* CHECKSUM_GEN_IP_INLINE */
929 IPH_OFFSET_SET(iphdr, 0);
930 IPH_ID_SET(iphdr, lwip_htons(ip_id));
931 #if CHECKSUM_GEN_IP_INLINE
932 chk_sum += iphdr->_id;
933 #endif /* CHECKSUM_GEN_IP_INLINE */
934 ++ip_id;
935
936 if (src == NULL) {
937 ip4_addr_copy(iphdr->src, *IP4_ADDR_ANY4);
938 } else {
939 /* src cannot be NULL here */
940 ip4_addr_copy(iphdr->src, *src);
941 }
942
943 #if CHECKSUM_GEN_IP_INLINE
944 chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
945 chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
946 chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
947 chk_sum = (chk_sum >> 16) + chk_sum;
948 chk_sum = ~chk_sum;
949 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
950 iphdr->_chksum = (u16_t)chk_sum; /* network order */
951 }
952 #if LWIP_CHECKSUM_CTRL_PER_NETIF
953 else {
954 IPH_CHKSUM_SET(iphdr, 0);
955 }
956 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF*/
957 #else /* CHECKSUM_GEN_IP_INLINE */
958 IPH_CHKSUM_SET(iphdr, 0);
959 #if CHECKSUM_GEN_IP
960 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
961 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
962 }
963 #endif /* CHECKSUM_GEN_IP */
964 #endif /* CHECKSUM_GEN_IP_INLINE */
965 } else {
966 /* IP header already included in p */
967 if (p->len < IP_HLEN) {
968 LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: LWIP_IP_HDRINCL but pbuf is too short\n"));
969 IP_STATS_INC(ip.err);
970 MIB2_STATS_INC(mib2.ipoutdiscards);
971 return ERR_BUF;
972 }
973 iphdr = (struct ip_hdr *)p->payload;
974 ip4_addr_copy(dest_addr, iphdr->dest);
975 dest = &dest_addr;
976 }
977
978 IP_STATS_INC(ip.xmit);
979
980 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
981 ip4_debug_print(p);
982
983 #if ENABLE_LOOPBACK
984 if (ip4_addr_cmp(dest, netif_ip4_addr(netif))
985 #if !LWIP_HAVE_LOOPIF
986 || ip4_addr_isloopback(dest)
987 #endif /* !LWIP_HAVE_LOOPIF */
988 ) {
989 /* Packet to self, enqueue it for loopback */
990 LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
991 return netif_loop_output(netif, p);
992 }
993 #if LWIP_MULTICAST_TX_OPTIONS
994 if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
995 netif_loop_output(netif, p);
996 }
997 #endif /* LWIP_MULTICAST_TX_OPTIONS */
998 #endif /* ENABLE_LOOPBACK */
999 #if IP_FRAG
1000 /* don't fragment if interface has mtu set to 0 [loopif] */
1001 if (netif->mtu && (p->tot_len > netif->mtu)) {
1002 return ip4_frag(p, netif, dest);
1003 }
1004 #endif /* IP_FRAG */
1005
1006 LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));
1007 return netif->output(netif, p, dest);
1008 }
1009
1010 /**
1011 * Simple interface to ip_output_if. It finds the outgoing network
1012 * interface and calls upon ip_output_if to do the actual work.
1013 *
1014 * @param p the packet to send (p->payload points to the data, e.g. next
1015 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
1016 IP header and p->payload points to that IP header)
1017 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
1018 * IP address of the netif used to send is used as source address)
1019 * @param dest the destination IP address to send the packet to
1020 * @param ttl the TTL value to be set in the IP header
1021 * @param tos the TOS value to be set in the IP header
1022 * @param proto the PROTOCOL to be set in the IP header
1023 *
1024 * @return ERR_RTE if no route is found
1025 * see ip_output_if() for more return values
1026 */
1027 err_t
1028 ip4_output(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
1029 u8_t ttl, u8_t tos, u8_t proto)
1030 {
1031 struct netif *netif;
1032
1033 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
1034
1035 if ((netif = ip4_route_src(src, dest)) == NULL) {
1036 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1037 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
1038 IP_STATS_INC(ip.rterr);
1039 return ERR_RTE;
1040 }
1041
1042 return ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1043 }
1044
1045 #if LWIP_NETIF_USE_HINTS
1046 /** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
1047 * before calling ip_output_if.
1048 *
1049 * @param p the packet to send (p->payload points to the data, e.g. next
1050 protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
1051 IP header and p->payload points to that IP header)
1052 * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
1053 * IP address of the netif used to send is used as source address)
1054 * @param dest the destination IP address to send the packet to
1055 * @param ttl the TTL value to be set in the IP header
1056 * @param tos the TOS value to be set in the IP header
1057 * @param proto the PROTOCOL to be set in the IP header
1058 * @param netif_hint netif output hint pointer set to netif->hint before
1059 * calling ip_output_if()
1060 *
1061 * @return ERR_RTE if no route is found
1062 * see ip_output_if() for more return values
1063 */
1064 err_t
1065 ip4_output_hinted(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
1066 u8_t ttl, u8_t tos, u8_t proto, struct netif_hint *netif_hint)
1067 {
1068 struct netif *netif;
1069 err_t err;
1070
1071 LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
1072
1073 if ((netif = ip4_route_src(src, dest)) == NULL) {
1074 LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1075 ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
1076 IP_STATS_INC(ip.rterr);
1077 return ERR_RTE;
1078 }
1079
1080 NETIF_SET_HINTS(netif, netif_hint);
1081 err = ip4_output_if(p, src, dest, ttl, tos, proto, netif);
1082 NETIF_RESET_HINTS(netif);
1083
1084 return err;
1085 }
1086 #endif /* LWIP_NETIF_USE_HINTS*/
1087
1088 #if IP_DEBUG
1089 /* Print an IP header by using LWIP_DEBUGF
1090 * @param p an IP packet, p->payload pointing to the IP header
1091 */
1092 void
1093 ip4_debug_print(struct pbuf *p)
1094 {
1095 struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
1096
1097 LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
1098 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1099 LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n",
1100 (u16_t)IPH_V(iphdr),
1101 (u16_t)IPH_HL(iphdr),
1102 (u16_t)IPH_TOS(iphdr),
1103 lwip_ntohs(IPH_LEN(iphdr))));
1104 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1105 LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n",
1106 lwip_ntohs(IPH_ID(iphdr)),
1107 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 15 & 1),
1108 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 14 & 1),
1109 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) >> 13 & 1),
1110 (u16_t)(lwip_ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)));
1111 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1112 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n",
1113 (u16_t)IPH_TTL(iphdr),
1114 (u16_t)IPH_PROTO(iphdr),
1115 lwip_ntohs(IPH_CHKSUM(iphdr))));
1116 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1117 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n",
1118 ip4_addr1_16_val(iphdr->src),
1119 ip4_addr2_16_val(iphdr->src),
1120 ip4_addr3_16_val(iphdr->src),
1121 ip4_addr4_16_val(iphdr->src)));
1122 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1123 LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n",
1124 ip4_addr1_16_val(iphdr->dest),
1125 ip4_addr2_16_val(iphdr->dest),
1126 ip4_addr3_16_val(iphdr->dest),
1127 ip4_addr4_16_val(iphdr->dest)));
1128 LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
1129 }
1130 #endif /* IP_DEBUG */
1131
1132 #endif /* LWIP_IPV4 */
1133