1/**
2 * @file
3 * Implementation of raw protocol PCBs for low-level handling of
4 * different types of protocols besides (or overriding) those
5 * already available in lwIP.\n
6 * See also @ref raw_raw
7 *
8 * @defgroup raw_raw RAW
9 * @ingroup callbackstyle_api
10 * Implementation of raw protocol PCBs for low-level handling of
11 * different types of protocols besides (or overriding) those
12 * already available in lwIP.\n
13 * @see @ref raw_api
14 */
15
16/*
17 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
18 * All rights reserved.
19 *
20 * Redistribution and use in source and binary forms, with or without modification,
21 * are permitted provided that the following conditions are met:
22 *
23 * 1. Redistributions of source code must retain the above copyright notice,
24 *    this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright notice,
26 *    this list of conditions and the following disclaimer in the documentation
27 *    and/or other materials provided with the distribution.
28 * 3. The name of the author may not be used to endorse or promote products
29 *    derived from this software without specific prior written permission.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
32 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
33 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
34 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
35 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
36 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
37 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
38 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
39 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
40 * OF SUCH DAMAGE.
41 *
42 * This file is part of the lwIP TCP/IP stack.
43 *
44 * Author: Adam Dunkels <adam@sics.se>
45 *
46 */
47
48#include "lwip/opt.h"
49
50#if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
51
52#include "lwip/def.h"
53#include "lwip/memp.h"
54#include "lwip/ip_addr.h"
55#include "lwip/netif.h"
56#include "lwip/raw.h"
57#include "lwip/stats.h"
58#include "lwip/ip6.h"
59#include "lwip/ip6_addr.h"
60#include "lwip/inet_chksum.h"
61
62#include <string.h>
63
64/** The list of RAW PCBs */
65static struct raw_pcb *raw_pcbs;
66
67static u8_t
68raw_input_match(struct raw_pcb *pcb, u8_t broadcast)
69{
70  LWIP_UNUSED_ARG(broadcast); /* in IPv6 only case */
71
72#if LWIP_IPV4 && LWIP_IPV6
73  /* Dual-stack: PCBs listening to any IP type also listen to any IP address */
74  if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
75#if IP_SOF_BROADCAST_RECV
76    if ((broadcast != 0) && !ip_get_option(pcb, SOF_BROADCAST)) {
77      return 0;
78    }
79#endif /* IP_SOF_BROADCAST_RECV */
80    return 1;
81  }
82#endif /* LWIP_IPV4 && LWIP_IPV6 */
83
84  /* Only need to check PCB if incoming IP version matches PCB IP version */
85  if (IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ip_current_dest_addr())) {
86#if LWIP_IPV4
87    /* Special case: IPv4 broadcast: receive all broadcasts
88     * Note: broadcast variable can only be 1 if it is an IPv4 broadcast */
89    if (broadcast != 0) {
90#if IP_SOF_BROADCAST_RECV
91      if (ip_get_option(pcb, SOF_BROADCAST))
92#endif /* IP_SOF_BROADCAST_RECV */
93      {
94        if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip))) {
95          return 1;
96        }
97      }
98    } else
99#endif /* LWIP_IPV4 */
100    /* Handle IPv4 and IPv6: catch all or exact match */
101    if (ip_addr_isany(&pcb->local_ip) ||
102       ip_addr_cmp(&pcb->local_ip, ip_current_dest_addr())) {
103      return 1;
104    }
105  }
106
107  return 0;
108}
109
110/**
111 * Determine if in incoming IP packet is covered by a RAW PCB
112 * and if so, pass it to a user-provided receive callback function.
113 *
114 * Given an incoming IP datagram (as a chain of pbufs) this function
115 * finds a corresponding RAW PCB and calls the corresponding receive
116 * callback function.
117 *
118 * @param p pbuf to be demultiplexed to a RAW PCB.
119 * @param inp network interface on which the datagram was received.
120 * @return - 1 if the packet has been eaten by a RAW PCB receive
121 *           callback function. The caller MAY NOT not reference the
122 *           packet any longer, and MAY NOT call pbuf_free().
123 * @return - 0 if packet is not eaten (pbuf is still referenced by the
124 *           caller).
125 *
126 */
127u8_t
128raw_input(struct pbuf *p, struct netif *inp)
129{
130  struct raw_pcb *pcb, *prev;
131  s16_t proto;
132  u8_t eaten = 0;
133  u8_t broadcast = ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif());
134
135  LWIP_UNUSED_ARG(inp);
136
137#if LWIP_IPV6
138#if LWIP_IPV4
139  if (IP_HDR_GET_VERSION(p->payload) == 6)
140#endif /* LWIP_IPV4 */
141  {
142    struct ip6_hdr *ip6hdr = (struct ip6_hdr *)p->payload;
143    proto = IP6H_NEXTH(ip6hdr);
144  }
145#if LWIP_IPV4
146  else
147#endif /* LWIP_IPV4 */
148#endif /* LWIP_IPV6 */
149#if LWIP_IPV4
150  {
151    proto = IPH_PROTO((struct ip_hdr *)p->payload);
152  }
153#endif /* LWIP_IPV4 */
154
155  prev = NULL;
156  pcb = raw_pcbs;
157  /* loop through all raw pcbs until the packet is eaten by one */
158  /* this allows multiple pcbs to match against the packet by design */
159  while ((eaten == 0) && (pcb != NULL)) {
160    if ((pcb->protocol == proto) && raw_input_match(pcb, broadcast)) {
161      /* receive callback function available? */
162      if (pcb->recv != NULL) {
163#ifndef LWIP_NOASSERT
164        void* old_payload = p->payload;
165#endif
166        /* the receive callback function did not eat the packet? */
167        eaten = pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr());
168        if (eaten != 0) {
169          /* receive function ate the packet */
170          p = NULL;
171          eaten = 1;
172          if (prev != NULL) {
173          /* move the pcb to the front of raw_pcbs so that is
174             found faster next time */
175            prev->next = pcb->next;
176            pcb->next = raw_pcbs;
177            raw_pcbs = pcb;
178          }
179        } else {
180          /* sanity-check that the receive callback did not alter the pbuf */
181          LWIP_ASSERT("raw pcb recv callback altered pbuf payload pointer without eating packet",
182            p->payload == old_payload);
183        }
184      }
185      /* no receive callback function was set for this raw PCB */
186    }
187    /* drop the packet */
188    prev = pcb;
189    pcb = pcb->next;
190  }
191  return eaten;
192}
193
194/**
195 * @ingroup raw_raw
196 * Bind a RAW PCB.
197 *
198 * @param pcb RAW PCB to be bound with a local address ipaddr.
199 * @param ipaddr local IP address to bind with. Use IP4_ADDR_ANY to
200 * bind to all local interfaces.
201 *
202 * @return lwIP error code.
203 * - ERR_OK. Successful. No error occurred.
204 * - ERR_USE. The specified IP address is already bound to by
205 * another RAW PCB.
206 *
207 * @see raw_disconnect()
208 */
209err_t
210raw_bind(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
211{
212  if ((pcb == NULL) || (ipaddr == NULL)) {
213    return ERR_VAL;
214  }
215  ip_addr_set_ipaddr(&pcb->local_ip, ipaddr);
216  return ERR_OK;
217}
218
219/**
220 * @ingroup raw_raw
221 * Connect an RAW PCB. This function is required by upper layers
222 * of lwip. Using the raw api you could use raw_sendto() instead
223 *
224 * This will associate the RAW PCB with the remote address.
225 *
226 * @param pcb RAW PCB to be connected with remote address ipaddr and port.
227 * @param ipaddr remote IP address to connect with.
228 *
229 * @return lwIP error code
230 *
231 * @see raw_disconnect() and raw_sendto()
232 */
233err_t
234raw_connect(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
235{
236  if ((pcb == NULL) || (ipaddr == NULL)) {
237    return ERR_VAL;
238  }
239  ip_addr_set_ipaddr(&pcb->remote_ip, ipaddr);
240  return ERR_OK;
241}
242
243/**
244 * @ingroup raw_raw
245 * Set the callback function for received packets that match the
246 * raw PCB's protocol and binding.
247 *
248 * The callback function MUST either
249 * - eat the packet by calling pbuf_free() and returning non-zero. The
250 *   packet will not be passed to other raw PCBs or other protocol layers.
251 * - not free the packet, and return zero. The packet will be matched
252 *   against further PCBs and/or forwarded to another protocol layers.
253 */
254void
255raw_recv(struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg)
256{
257  /* remember recv() callback and user data */
258  pcb->recv = recv;
259  pcb->recv_arg = recv_arg;
260}
261
262/**
263 * @ingroup raw_raw
264 * Send the raw IP packet to the given address. Note that actually you cannot
265 * modify the IP headers (this is inconsistent with the receive callback where
266 * you actually get the IP headers), you can only specify the IP payload here.
267 * It requires some more changes in lwIP. (there will be a raw_send() function
268 * then.)
269 *
270 * @param pcb the raw pcb which to send
271 * @param p the IP payload to send
272 * @param ipaddr the destination address of the IP packet
273 *
274 */
275err_t
276raw_sendto(struct raw_pcb *pcb, struct pbuf *p, const ip_addr_t *ipaddr)
277{
278  err_t err;
279  struct netif *netif;
280  const ip_addr_t *src_ip;
281  struct pbuf *q; /* q will be sent down the stack */
282  s16_t header_size;
283
284  if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, ipaddr)) {
285    return ERR_VAL;
286  }
287
288  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
289
290  header_size = (
291#if LWIP_IPV4 && LWIP_IPV6
292    IP_IS_V6(ipaddr) ? IP6_HLEN : IP_HLEN);
293#elif LWIP_IPV4
294    IP_HLEN);
295#else
296    IP6_HLEN);
297#endif
298
299  /* not enough space to add an IP header to first pbuf in given p chain? */
300  if (pbuf_header(p, header_size)) {
301    /* allocate header in new pbuf */
302    q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
303    /* new header pbuf could not be allocated? */
304    if (q == NULL) {
305      LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
306      return ERR_MEM;
307    }
308    if (p->tot_len != 0) {
309      /* chain header q in front of given pbuf p */
310      pbuf_chain(q, p);
311    }
312    /* { first pbuf q points to header pbuf } */
313    LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
314  } else {
315    /* first pbuf q equals given pbuf */
316    q = p;
317    if (pbuf_header(q, -header_size)) {
318      LWIP_ASSERT("Can't restore header we just removed!", 0);
319      return ERR_MEM;
320    }
321  }
322
323  if(IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
324    /* Don't call ip_route() with IP_ANY_TYPE */
325    netif = ip_route(IP46_ADDR_ANY(IP_GET_TYPE(ipaddr)), ipaddr);
326  } else {
327    netif = ip_route(&pcb->local_ip, ipaddr);
328  }
329
330  if (netif == NULL) {
331    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to "));
332    ip_addr_debug_print(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ipaddr);
333    /* free any temporary header pbuf allocated by pbuf_header() */
334    if (q != p) {
335      pbuf_free(q);
336    }
337    return ERR_RTE;
338  }
339
340#if IP_SOF_BROADCAST
341  if (IP_IS_V4(ipaddr))
342  {
343    /* broadcast filter? */
344    if (!ip_get_option(pcb, SOF_BROADCAST) && ip_addr_isbroadcast(ipaddr, netif)) {
345      LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
346      /* free any temporary header pbuf allocated by pbuf_header() */
347      if (q != p) {
348        pbuf_free(q);
349      }
350      return ERR_VAL;
351    }
352  }
353#endif /* IP_SOF_BROADCAST */
354
355  if (ip_addr_isany(&pcb->local_ip)) {
356    /* use outgoing network interface IP address as source address */
357    src_ip = ip_netif_get_local_ip(netif, ipaddr);
358#if LWIP_IPV6
359    if (src_ip == NULL) {
360      if (q != p) {
361        pbuf_free(q);
362      }
363      return ERR_RTE;
364    }
365#endif /* LWIP_IPV6 */
366  } else {
367    /* use RAW PCB local IP address as source address */
368    src_ip = &pcb->local_ip;
369  }
370
371#if LWIP_IPV6
372  /* If requested, based on the IPV6_CHECKSUM socket option per RFC3542,
373     compute the checksum and update the checksum in the payload. */
374  if (IP_IS_V6(ipaddr) && pcb->chksum_reqd) {
375    u16_t chksum = ip6_chksum_pseudo(p, pcb->protocol, p->tot_len, ip_2_ip6(src_ip), ip_2_ip6(ipaddr));
376    LWIP_ASSERT("Checksum must fit into first pbuf", p->len >= (pcb->chksum_offset + 2));
377    SMEMCPY(((u8_t *)p->payload) + pcb->chksum_offset, &chksum, sizeof(u16_t));
378  }
379#endif
380
381  NETIF_SET_HWADDRHINT(netif, &pcb->addr_hint);
382  err = ip_output_if(q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
383  NETIF_SET_HWADDRHINT(netif, NULL);
384
385  /* did we chain a header earlier? */
386  if (q != p) {
387    /* free the header */
388    pbuf_free(q);
389  }
390  return err;
391}
392
393/**
394 * @ingroup raw_raw
395 * Send the raw IP packet to the address given by raw_connect()
396 *
397 * @param pcb the raw pcb which to send
398 * @param p the IP payload to send
399 *
400 */
401err_t
402raw_send(struct raw_pcb *pcb, struct pbuf *p)
403{
404  return raw_sendto(pcb, p, &pcb->remote_ip);
405}
406
407/**
408 * @ingroup raw_raw
409 * Remove an RAW PCB.
410 *
411 * @param pcb RAW PCB to be removed. The PCB is removed from the list of
412 * RAW PCB's and the data structure is freed from memory.
413 *
414 * @see raw_new()
415 */
416void
417raw_remove(struct raw_pcb *pcb)
418{
419  struct raw_pcb *pcb2;
420  /* pcb to be removed is first in list? */
421  if (raw_pcbs == pcb) {
422    /* make list start at 2nd pcb */
423    raw_pcbs = raw_pcbs->next;
424    /* pcb not 1st in list */
425  } else {
426    for (pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
427      /* find pcb in raw_pcbs list */
428      if (pcb2->next != NULL && pcb2->next == pcb) {
429        /* remove pcb from list */
430        pcb2->next = pcb->next;
431        break;
432      }
433    }
434  }
435  memp_free(MEMP_RAW_PCB, pcb);
436}
437
438/**
439 * @ingroup raw_raw
440 * Create a RAW PCB.
441 *
442 * @return The RAW PCB which was created. NULL if the PCB data structure
443 * could not be allocated.
444 *
445 * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
446 *
447 * @see raw_remove()
448 */
449struct raw_pcb *
450raw_new(u8_t proto)
451{
452  struct raw_pcb *pcb;
453
454  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
455
456  pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
457  /* could allocate RAW PCB? */
458  if (pcb != NULL) {
459    /* initialize PCB to all zeroes */
460    memset(pcb, 0, sizeof(struct raw_pcb));
461    pcb->protocol = proto;
462    pcb->ttl = RAW_TTL;
463    pcb->next = raw_pcbs;
464    raw_pcbs = pcb;
465  }
466  return pcb;
467}
468
469/**
470 * @ingroup raw_raw
471 * Create a RAW PCB for specific IP type.
472 *
473 * @return The RAW PCB which was created. NULL if the PCB data structure
474 * could not be allocated.
475 *
476 * @param type IP address type, see @ref lwip_ip_addr_type definitions.
477 * If you want to listen to IPv4 and IPv6 (dual-stack) packets,
478 * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
479 * @param proto the protocol number (next header) of the IPv6 packet payload
480 *              (e.g. IP6_NEXTH_ICMP6)
481 *
482 * @see raw_remove()
483 */
484struct raw_pcb *
485raw_new_ip_type(u8_t type, u8_t proto)
486{
487  struct raw_pcb *pcb;
488  pcb = raw_new(proto);
489#if LWIP_IPV4 && LWIP_IPV6
490  if (pcb != NULL) {
491    IP_SET_TYPE_VAL(pcb->local_ip,  type);
492    IP_SET_TYPE_VAL(pcb->remote_ip, type);
493  }
494#else /* LWIP_IPV4 && LWIP_IPV6 */
495  LWIP_UNUSED_ARG(type);
496#endif /* LWIP_IPV4 && LWIP_IPV6 */
497  return pcb;
498}
499
500/** This function is called from netif.c when address is changed
501 *
502 * @param old_addr IP address of the netif before change
503 * @param new_addr IP address of the netif after change
504 */
505void raw_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr)
506{
507  struct raw_pcb* rpcb;
508
509  if (!ip_addr_isany(old_addr) && !ip_addr_isany(new_addr)) {
510    for (rpcb = raw_pcbs; rpcb != NULL; rpcb = rpcb->next) {
511      /* PCB bound to current local interface address? */
512      if (ip_addr_cmp(&rpcb->local_ip, old_addr)) {
513        /* The PCB is bound to the old ipaddr and
514         * is set to bound to the new one instead */
515        ip_addr_copy(rpcb->local_ip, *new_addr);
516      }
517    }
518  }
519}
520
521#endif /* LWIP_RAW */
522