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 */
65 static struct raw_pcb *raw_pcbs;
66 
67 static u8_t
raw_input_match(struct raw_pcb * pcb,u8_t broadcast)68 raw_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  */
127 u8_t
raw_input(struct pbuf * p,struct netif * inp)128 raw_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  */
209 err_t
raw_bind(struct raw_pcb * pcb,const ip_addr_t * ipaddr)210 raw_bind(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
211 {
212   if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ipaddr)) {
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  */
233 err_t
raw_connect(struct raw_pcb * pcb,const ip_addr_t * ipaddr)234 raw_connect(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
235 {
236   if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ipaddr)) {
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  */
254 void
raw_recv(struct raw_pcb * pcb,raw_recv_fn recv,void * recv_arg)255 raw_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  */
275 err_t
raw_sendto(struct raw_pcb * pcb,struct pbuf * p,const ip_addr_t * ipaddr)276 raw_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   const ip_addr_t *dst_ip = ipaddr;
284 
285   if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, ipaddr)) {
286     return ERR_VAL;
287   }
288 
289   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
290 
291   header_size = (
292 #if LWIP_IPV4 && LWIP_IPV6
293     IP_IS_V6(ipaddr) ? IP6_HLEN : IP_HLEN);
294 #elif LWIP_IPV4
295     IP_HLEN);
296 #else
297     IP6_HLEN);
298 #endif
299 
300   /* not enough space to add an IP header to first pbuf in given p chain? */
301   if (pbuf_header(p, header_size)) {
302     /* allocate header in new pbuf */
303     q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
304     /* new header pbuf could not be allocated? */
305     if (q == NULL) {
306       LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
307       return ERR_MEM;
308     }
309     if (p->tot_len != 0) {
310       /* chain header q in front of given pbuf p */
311       pbuf_chain(q, p);
312     }
313     /* { first pbuf q points to header pbuf } */
314     LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
315   } else {
316     /* first pbuf q equals given pbuf */
317     q = p;
318     if (pbuf_header(q, -header_size)) {
319       LWIP_ASSERT("Can't restore header we just removed!", 0);
320       return ERR_MEM;
321     }
322   }
323 
324   netif = ip_route(&pcb->local_ip, dst_ip);
325   if (netif == NULL) {
326     LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to "));
327     ip_addr_debug_print(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, dst_ip);
328     /* free any temporary header pbuf allocated by pbuf_header() */
329     if (q != p) {
330       pbuf_free(q);
331     }
332     return ERR_RTE;
333   }
334 
335 #if IP_SOF_BROADCAST
336   if (IP_IS_V4(ipaddr))
337   {
338     /* broadcast filter? */
339     if (!ip_get_option(pcb, SOF_BROADCAST) && ip_addr_isbroadcast(ipaddr, netif)) {
340       LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
341       /* free any temporary header pbuf allocated by pbuf_header() */
342       if (q != p) {
343         pbuf_free(q);
344       }
345       return ERR_VAL;
346     }
347   }
348 #endif /* IP_SOF_BROADCAST */
349 
350   if (ip_addr_isany(&pcb->local_ip)) {
351     /* use outgoing network interface IP address as source address */
352     src_ip = ip_netif_get_local_ip(netif, dst_ip);
353 #if LWIP_IPV6
354     if (src_ip == NULL) {
355       if (q != p) {
356         pbuf_free(q);
357       }
358       return ERR_RTE;
359     }
360 #endif /* LWIP_IPV6 */
361   } else {
362     /* use RAW PCB local IP address as source address */
363     src_ip = &pcb->local_ip;
364   }
365 
366 #if LWIP_IPV6
367   /* If requested, based on the IPV6_CHECKSUM socket option per RFC3542,
368      compute the checksum and update the checksum in the payload. */
369   if (IP_IS_V6(dst_ip) && pcb->chksum_reqd) {
370     u16_t chksum = ip6_chksum_pseudo(p, pcb->protocol, p->tot_len, ip_2_ip6(src_ip), ip_2_ip6(dst_ip));
371     LWIP_ASSERT("Checksum must fit into first pbuf", p->len >= (pcb->chksum_offset + 2));
372     SMEMCPY(((u8_t *)p->payload) + pcb->chksum_offset, &chksum, sizeof(u16_t));
373   }
374 #endif
375 
376   NETIF_SET_HWADDRHINT(netif, &pcb->addr_hint);
377   err = ip_output_if(q, src_ip, dst_ip, pcb->ttl, pcb->tos, pcb->protocol, netif);
378   NETIF_SET_HWADDRHINT(netif, NULL);
379 
380   /* did we chain a header earlier? */
381   if (q != p) {
382     /* free the header */
383     pbuf_free(q);
384   }
385   return err;
386 }
387 
388 /**
389  * @ingroup raw_raw
390  * Send the raw IP packet to the address given by raw_connect()
391  *
392  * @param pcb the raw pcb which to send
393  * @param p the IP payload to send
394  *
395  */
396 err_t
raw_send(struct raw_pcb * pcb,struct pbuf * p)397 raw_send(struct raw_pcb *pcb, struct pbuf *p)
398 {
399   return raw_sendto(pcb, p, &pcb->remote_ip);
400 }
401 
402 /**
403  * @ingroup raw_raw
404  * Remove an RAW PCB.
405  *
406  * @param pcb RAW PCB to be removed. The PCB is removed from the list of
407  * RAW PCB's and the data structure is freed from memory.
408  *
409  * @see raw_new()
410  */
411 void
raw_remove(struct raw_pcb * pcb)412 raw_remove(struct raw_pcb *pcb)
413 {
414   struct raw_pcb *pcb2;
415   /* pcb to be removed is first in list? */
416   if (raw_pcbs == pcb) {
417     /* make list start at 2nd pcb */
418     raw_pcbs = raw_pcbs->next;
419     /* pcb not 1st in list */
420   } else {
421     for (pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
422       /* find pcb in raw_pcbs list */
423       if (pcb2->next != NULL && pcb2->next == pcb) {
424         /* remove pcb from list */
425         pcb2->next = pcb->next;
426         break;
427       }
428     }
429   }
430   memp_free(MEMP_RAW_PCB, pcb);
431 }
432 
433 /**
434  * @ingroup raw_raw
435  * Create a RAW PCB.
436  *
437  * @return The RAW PCB which was created. NULL if the PCB data structure
438  * could not be allocated.
439  *
440  * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
441  *
442  * @see raw_remove()
443  */
444 struct raw_pcb *
raw_new(u8_t proto)445 raw_new(u8_t proto)
446 {
447   struct raw_pcb *pcb;
448 
449   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
450 
451   pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
452   /* could allocate RAW PCB? */
453   if (pcb != NULL) {
454     /* initialize PCB to all zeroes */
455     memset(pcb, 0, sizeof(struct raw_pcb));
456     pcb->protocol = proto;
457     pcb->ttl = RAW_TTL;
458     pcb->next = raw_pcbs;
459     raw_pcbs = pcb;
460   }
461   return pcb;
462 }
463 
464 /**
465  * @ingroup raw_raw
466  * Create a RAW PCB for specific IP type.
467  *
468  * @return The RAW PCB which was created. NULL if the PCB data structure
469  * could not be allocated.
470  *
471  * @param type IP address type, see @ref lwip_ip_addr_type definitions.
472  * If you want to listen to IPv4 and IPv6 (dual-stack) packets,
473  * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
474  * @param proto the protocol number (next header) of the IPv6 packet payload
475  *              (e.g. IP6_NEXTH_ICMP6)
476  *
477  * @see raw_remove()
478  */
479 struct raw_pcb *
raw_new_ip_type(u8_t type,u8_t proto)480 raw_new_ip_type(u8_t type, u8_t proto)
481 {
482   struct raw_pcb *pcb;
483   pcb = raw_new(proto);
484 #if LWIP_IPV4 && LWIP_IPV6
485   if (pcb != NULL) {
486     IP_SET_TYPE_VAL(pcb->local_ip,  type);
487     IP_SET_TYPE_VAL(pcb->remote_ip, type);
488   }
489 #else /* LWIP_IPV4 && LWIP_IPV6 */
490   LWIP_UNUSED_ARG(type);
491 #endif /* LWIP_IPV4 && LWIP_IPV6 */
492   return pcb;
493 }
494 
495 /** This function is called from netif.c when address is changed
496  *
497  * @param old_addr IP address of the netif before change
498  * @param new_addr IP address of the netif after change
499  */
raw_netif_ip_addr_changed(const ip_addr_t * old_addr,const ip_addr_t * new_addr)500 void raw_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr)
501 {
502   struct raw_pcb* rpcb;
503 
504   if (!ip_addr_isany(old_addr) && !ip_addr_isany(new_addr)) {
505     for (rpcb = raw_pcbs; rpcb != NULL; rpcb = rpcb->next) {
506       /* PCB bound to current local interface address? */
507       if (ip_addr_cmp(&rpcb->local_ip, old_addr)) {
508         /* The PCB is bound to the old ipaddr and
509          * is set to bound to the new one instead */
510         ip_addr_copy(rpcb->local_ip, *new_addr);
511       }
512     }
513   }
514 }
515 
516 #endif /* LWIP_RAW */
517