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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.
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_RAW /* don't build if not configured for use in lwipopts.h */
44
45#include "lwip/def.h"
46#include "lwip/memp.h"
47#include "lwip/inet.h"
48#include "lwip/ip_addr.h"
49#include "lwip/netif.h"
50#include "lwip/raw.h"
51#include "lwip/stats.h"
52#include "lwip/snmp.h"
53#include "arch/perf.h"
54
55#include <string.h>
56
57/** The list of RAW PCBs */
58static struct raw_pcb *raw_pcbs;
59
60/**
61 * Determine if in incoming IP packet is covered by a RAW PCB
62 * and if so, pass it to a user-provided receive callback function.
63 *
64 * Given an incoming IP datagram (as a chain of pbufs) this function
65 * finds a corresponding RAW PCB and calls the corresponding receive
66 * callback function.
67 *
68 * @param p pbuf to be demultiplexed to a RAW PCB.
69 * @param inp network interface on which the datagram was received.
70 * @return - 1 if the packet has been eaten by a RAW PCB receive
71 * callback function. The caller MAY NOT not reference the
72 * packet any longer, and MAY NOT call pbuf_free().
73 * @return - 0 if packet is not eaten (pbuf is still referenced by the
74 * caller).
75 *
76 */
77u8_t
78raw_input(struct pbuf *p, struct netif *inp)
79{
80 struct raw_pcb *pcb, *prev;
81 struct ip_hdr *iphdr;
82 s16_t proto;
83 u8_t eaten = 0;
84
85 LWIP_UNUSED_ARG(inp);
86
87 iphdr = p->payload;
88 proto = IPH_PROTO(iphdr);
89
90 prev = NULL;
91 pcb = raw_pcbs;
92 /* loop through all raw pcbs until the packet is eaten by one */
93 /* this allows multiple pcbs to match against the packet by design */
94 while ((eaten == 0) && (pcb != NULL)) {
95 if (pcb->protocol == proto) {
96 /* receive callback function available? */
97 if (pcb->recv != NULL) {
98 /* the receive callback function did not eat the packet? */
99 if (pcb->recv(pcb->recv_arg, pcb, p, &(iphdr->src)) != 0)
100 {
101 /* receive function ate the packet */
102 p = NULL;
103 eaten = 1;
104 if (prev != NULL) {
105 /* move the pcb to the front of raw_pcbs so that is
106 found faster next time */
107 prev->next = pcb->next;
108 pcb->next = raw_pcbs;
109 raw_pcbs = pcb;
110 }
111 }
112 }
113 /* no receive callback function was set for this raw PCB */
114 /* drop the packet */
115 }
116 prev = pcb;
117 pcb = pcb->next;
118 }
119 return eaten;
120}
121
122/**
123 * Bind a RAW PCB.
124 *
125 * @param pcb RAW PCB to be bound with a local address ipaddr.
126 * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
127 * bind to all local interfaces.
128 *
129 * @return lwIP error code.
130 * - ERR_OK. Successful. No error occured.
131 * - ERR_USE. The specified IP address is already bound to by
132 * another RAW PCB.
133 *
134 * @see raw_disconnect()
135 */
136err_t
137raw_bind(struct raw_pcb *pcb, struct ip_addr *ipaddr)
138{
139 ip_addr_set(&pcb->local_ip, ipaddr);
140 return ERR_OK;
141}
142
143/**
144 * Connect an RAW PCB. This function is required by upper layers
145 * of lwip. Using the raw api you could use raw_sendto() instead
146 *
147 * This will associate the RAW PCB with the remote address.
148 *
149 * @param pcb RAW PCB to be connected with remote address ipaddr and port.
150 * @param ipaddr remote IP address to connect with.
151 *
152 * @return lwIP error code
153 *
154 * @see raw_disconnect() and raw_sendto()
155 */
156err_t
157raw_connect(struct raw_pcb *pcb, struct ip_addr *ipaddr)
158{
159 ip_addr_set(&pcb->remote_ip, ipaddr);
160 return ERR_OK;
161}
162
163
164/**
165 * Set the callback function for received packets that match the
166 * raw PCB's protocol and binding.
167 *
168 * The callback function MUST either
169 * - eat the packet by calling pbuf_free() and returning non-zero. The
170 * packet will not be passed to other raw PCBs or other protocol layers.
171 * - not free the packet, and return zero. The packet will be matched
172 * against further PCBs and/or forwarded to another protocol layers.
173 *
174 * @return non-zero if the packet was free()d, zero if the packet remains
175 * available for others.
176 */
177void
178raw_recv(struct raw_pcb *pcb,
179 u8_t (* recv)(void *arg, struct raw_pcb *upcb, struct pbuf *p,
180 struct ip_addr *addr),
181 void *recv_arg)
182{
183 /* remember recv() callback and user data */
184 pcb->recv = recv;
185 pcb->recv_arg = recv_arg;
186}
187
188/**
189 * Send the raw IP packet to the given address. Note that actually you cannot
190 * modify the IP headers (this is inconsistent with the receive callback where
191 * you actually get the IP headers), you can only specify the IP payload here.
192 * It requires some more changes in lwIP. (there will be a raw_send() function
193 * then.)
194 *
195 * @param pcb the raw pcb which to send
196 * @param p the IP payload to send
197 * @param ipaddr the destination address of the IP packet
198 *
199 */
200err_t
201raw_sendto(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr)
202{
203 err_t err;
204 struct netif *netif;
205 struct ip_addr *src_ip;
206 struct pbuf *q; /* q will be sent down the stack */
207
208 LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_sendto\n"));
209
210 /* not enough space to add an IP header to first pbuf in given p chain? */
211 if (pbuf_header(p, IP_HLEN)) {
212 /* allocate header in new pbuf */
213 q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
214 /* new header pbuf could not be allocated? */
215 if (q == NULL) {
216 LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 2, ("raw_sendto: could not allocate header\n"));
217 return ERR_MEM;
218 }
219 /* chain header q in front of given pbuf p */
220 pbuf_chain(q, p);
221 /* { first pbuf q points to header pbuf } */
222 LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
223 } else {
224 /* first pbuf q equals given pbuf */
225 q = p;
226 if(pbuf_header(q, -IP_HLEN)) {
227 LWIP_ASSERT("Can't restore header we just removed!", 0);
228 return ERR_MEM;
229 }
230 }
231
232 if ((netif = ip_route(ipaddr)) == NULL) {
233 LWIP_DEBUGF(RAW_DEBUG | 1, ("raw_sendto: No route to 0x%"X32_F"\n", ipaddr->addr));
234 /* free any temporary header pbuf allocated by pbuf_header() */
235 if (q != p) {
236 pbuf_free(q);
237 }
238 return ERR_RTE;
239 }
240
241 if (ip_addr_isany(&pcb->local_ip)) {
242 /* use outgoing network interface IP address as source address */
243 src_ip = &(netif->ip_addr);
244 } else {
245 /* use RAW PCB local IP address as source address */
246 src_ip = &(pcb->local_ip);
247 }
248
249#if LWIP_NETIF_HWADDRHINT
250 netif->addr_hint = &(pcb->addr_hint);
251#endif /* LWIP_NETIF_HWADDRHINT*/
252 err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
253#if LWIP_NETIF_HWADDRHINT
254 netif->addr_hint = NULL;
255#endif /* LWIP_NETIF_HWADDRHINT*/
256
257 /* did we chain a header earlier? */
258 if (q != p) {
259 /* free the header */
260 pbuf_free(q);
261 }
262 return err;
263}
264
265/**
266 * Send the raw IP packet to the address given by raw_connect()
267 *
268 * @param pcb the raw pcb which to send
269 * @param p the IP payload to send
270 *
271 */
272err_t
273raw_send(struct raw_pcb *pcb, struct pbuf *p)
274{
275 return raw_sendto(pcb, p, &pcb->remote_ip);
276}
277
278/**
279 * Remove an RAW PCB.
280 *
281 * @param pcb RAW PCB to be removed. The PCB is removed from the list of
282 * RAW PCB's and the data structure is freed from memory.
283 *
284 * @see raw_new()
285 */
286void
287raw_remove(struct raw_pcb *pcb)
288{
289 struct raw_pcb *pcb2;
290 /* pcb to be removed is first in list? */
291 if (raw_pcbs == pcb) {
292 /* make list start at 2nd pcb */
293 raw_pcbs = raw_pcbs->next;
294 /* pcb not 1st in list */
295 } else {
296 for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
297 /* find pcb in raw_pcbs list */
298 if (pcb2->next != NULL && pcb2->next == pcb) {
299 /* remove pcb from list */
300 pcb2->next = pcb->next;
301 }
302 }
303 }
304 memp_free(MEMP_RAW_PCB, pcb);
305}
306
307/**
308 * Create a RAW PCB.
309 *
310 * @return The RAW PCB which was created. NULL if the PCB data structure
311 * could not be allocated.
312 *
313 * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
314 *
315 * @see raw_remove()
316 */
317struct raw_pcb *
318raw_new(u8_t proto) {
319 struct raw_pcb *pcb;
320
321 LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_new\n"));
322
323 pcb = memp_malloc(MEMP_RAW_PCB);
324 /* could allocate RAW PCB? */
325 if (pcb != NULL) {
326 /* initialize PCB to all zeroes */
327 memset(pcb, 0, sizeof(struct raw_pcb));
328 pcb->protocol = proto;
329 pcb->ttl = RAW_TTL;
330 pcb->next = raw_pcbs;
331 raw_pcbs = pcb;
332 }
333 return pcb;
334}
335
336#endif /* LWIP_RAW */
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