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 raw_input(struct pbuf *p, struct netif *inp)
78{
79    struct raw_pcb *pcb, *prev;
80    struct ip_hdr *iphdr;
81    s16_t proto;
82    u8_t eaten = 0;
83
84    LWIP_UNUSED_ARG(inp);
85
86    iphdr = p->payload;
87    proto = IPH_PROTO(iphdr);
88
89    prev = NULL;
90    pcb = raw_pcbs;
91    /* loop through all raw pcbs until the packet is eaten by one */
92    /* this allows multiple pcbs to match against the packet by design */
93    while ((eaten == 0) && (pcb != NULL)) {
94        if (pcb->protocol == proto) {
95#if IP_SOF_BROADCAST_RECV
96            /* broadcast filter? */
97            if ((pcb->so_options & SOF_BROADCAST)
98                || !ip_addr_isbroadcast(&(iphdr->dest), inp))
99#endif                          /* IP_SOF_BROADCAST_RECV */
100            {
101                /* receive callback function available? */
102                if (pcb->recv != NULL) {
103                    /* the receive callback function did not eat the packet? */
104                    if (pcb->recv(pcb->recv_arg, pcb, p, &(iphdr->src)) != 0) {
105                        /* receive function ate the packet */
106                        p = NULL;
107                        eaten = 1;
108                        if (prev != NULL) {
109                            /* move the pcb to the front of raw_pcbs so that is
110                               found faster next time */
111                            prev->next = pcb->next;
112                            pcb->next = raw_pcbs;
113                            raw_pcbs = pcb;
114                        }
115                    }
116                }
117                /* no receive callback function was set for this raw PCB */
118            }
119            /* drop the packet */
120        }
121        prev = pcb;
122        pcb = pcb->next;
123    }
124    return eaten;
125}
126
127/**
128 * Bind a RAW PCB.
129 *
130 * @param pcb RAW PCB to be bound with a local address ipaddr.
131 * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
132 * bind to all local interfaces.
133 *
134 * @return lwIP error code.
135 * - ERR_OK. Successful. No error occured.
136 * - ERR_USE. The specified IP address is already bound to by
137 * another RAW PCB.
138 *
139 * @see raw_disconnect()
140 */
141err_t raw_bind(struct raw_pcb * pcb, struct ip_addr * ipaddr)
142{
143    ip_addr_set(&pcb->local_ip, ipaddr);
144    return ERR_OK;
145}
146
147/**
148 * Connect an RAW PCB. This function is required by upper layers
149 * of lwip. Using the raw api you could use raw_sendto() instead
150 *
151 * This will associate the RAW PCB with the remote address.
152 *
153 * @param pcb RAW PCB to be connected with remote address ipaddr and port.
154 * @param ipaddr remote IP address to connect with.
155 *
156 * @return lwIP error code
157 *
158 * @see raw_disconnect() and raw_sendto()
159 */
160err_t raw_connect(struct raw_pcb * pcb, struct ip_addr * ipaddr)
161{
162    ip_addr_set(&pcb->remote_ip, ipaddr);
163    return ERR_OK;
164}
165
166
167/**
168 * Set the callback function for received packets that match the
169 * raw PCB's protocol and binding.
170 *
171 * The callback function MUST either
172 * - eat the packet by calling pbuf_free() and returning non-zero. The
173 *   packet will not be passed to other raw PCBs or other protocol layers.
174 * - not free the packet, and return zero. The packet will be matched
175 *   against further PCBs and/or forwarded to another protocol layers.
176 *
177 * @return non-zero if the packet was free()d, zero if the packet remains
178 * available for others.
179 */
180void
181raw_recv(struct raw_pcb *pcb,
182         u8_t(*recv) (void *arg, struct raw_pcb * upcb, struct pbuf * p,
183                      struct ip_addr * addr), void *recv_arg)
184{
185    /* remember recv() callback and user data */
186    pcb->recv = recv;
187    pcb->recv_arg = recv_arg;
188}
189
190/**
191 * Send the raw IP packet to the given address. Note that actually you cannot
192 * modify the IP headers (this is inconsistent with the receive callback where
193 * you actually get the IP headers), you can only specify the IP payload here.
194 * It requires some more changes in lwIP. (there will be a raw_send() function
195 * then.)
196 *
197 * @param pcb the raw pcb which to send
198 * @param p the IP payload to send
199 * @param ipaddr the destination address of the IP packet
200 *
201 */
202err_t raw_sendto(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr)
203{
204    err_t err;
205    struct netif *netif;
206    struct ip_addr *src_ip;
207    struct pbuf *q;             /* q will be sent down the stack */
208
209    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_sendto\n"));
210
211    /* not enough space to add an IP header to first pbuf in given p chain? */
212    if (pbuf_header(p, IP_HLEN)) {
213        /* allocate header in new pbuf */
214        q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
215        /* new header pbuf could not be allocated? */
216        if (q == NULL) {
217            LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 2,
218                        ("raw_sendto: could not allocate header\n"));
219            return ERR_MEM;
220        }
221        /* chain header q in front of given pbuf p */
222        pbuf_chain(q, p);
223        /* { first pbuf q points to header pbuf } */
224        LWIP_DEBUGF(RAW_DEBUG,
225                    ("raw_sendto: added header pbuf %p before given pbuf %p\n",
226                     (void *) q, (void *) p));
227    } else {
228        /* first pbuf q equals given pbuf */
229        q = p;
230        if (pbuf_header(q, -IP_HLEN)) {
231            LWIP_ASSERT("Can't restore header we just removed!", 0);
232            return ERR_MEM;
233        }
234    }
235
236    if ((netif = ip_route(ipaddr)) == NULL) {
237        LWIP_DEBUGF(RAW_DEBUG | 1,
238                    ("raw_sendto: No route to 0x%" X32_F "\n", ipaddr->addr));
239        /* free any temporary header pbuf allocated by pbuf_header() */
240        if (q != p) {
241            pbuf_free(q);
242        }
243        return ERR_RTE;
244    }
245#if IP_SOF_BROADCAST
246    /* broadcast filter? */
247    if (((pcb->so_options & SOF_BROADCAST) == 0)
248        && ip_addr_isbroadcast(ipaddr, netif)) {
249        LWIP_DEBUGF(RAW_DEBUG | 1,
250                    ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n",
251                     (void *) pcb));
252        /* free any temporary header pbuf allocated by pbuf_header() */
253        if (q != p) {
254            pbuf_free(q);
255        }
256        return ERR_VAL;
257    }
258#endif                          /* IP_SOF_BROADCAST */
259
260    if (ip_addr_isany(&pcb->local_ip)) {
261        /* use outgoing network interface IP address as source address */
262        src_ip = &(netif->ip_addr);
263    } else {
264        /* use RAW PCB local IP address as source address */
265        src_ip = &(pcb->local_ip);
266    }
267
268#if LWIP_NETIF_HWADDRHINT
269    netif->addr_hint = &(pcb->addr_hint);
270#endif                          /* LWIP_NETIF_HWADDRHINT */
271    err =
272      ip_output_if(q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
273#if LWIP_NETIF_HWADDRHINT
274    netif->addr_hint = NULL;
275#endif                          /* LWIP_NETIF_HWADDRHINT */
276
277    /* did we chain a header earlier? */
278    if (q != p) {
279        /* free the header */
280        pbuf_free(q);
281    }
282    return err;
283}
284
285/**
286 * Send the raw IP packet to the address given by raw_connect()
287 *
288 * @param pcb the raw pcb which to send
289 * @param p the IP payload to send
290 *
291 */
292err_t raw_send(struct raw_pcb * pcb, struct pbuf * p)
293{
294    return raw_sendto(pcb, p, &pcb->remote_ip);
295}
296
297/**
298 * Remove an RAW PCB.
299 *
300 * @param pcb RAW PCB to be removed. The PCB is removed from the list of
301 * RAW PCB's and the data structure is freed from memory.
302 *
303 * @see raw_new()
304 */
305void raw_remove(struct raw_pcb *pcb)
306{
307    struct raw_pcb *pcb2;
308
309    /* pcb to be removed is first in list? */
310    if (raw_pcbs == pcb) {
311        /* make list start at 2nd pcb */
312        raw_pcbs = raw_pcbs->next;
313        /* pcb not 1st in list */
314    } else {
315        for (pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
316            /* find pcb in raw_pcbs list */
317            if (pcb2->next != NULL && pcb2->next == pcb) {
318                /* remove pcb from list */
319                pcb2->next = pcb->next;
320            }
321        }
322    }
323    memp_free(MEMP_RAW_PCB, pcb);
324}
325
326/**
327 * Create a RAW PCB.
328 *
329 * @return The RAW PCB which was created. NULL if the PCB data structure
330 * could not be allocated.
331 *
332 * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
333 *
334 * @see raw_remove()
335 */
336struct raw_pcb *raw_new(u8_t proto)
337{
338    struct raw_pcb *pcb;
339
340    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_new\n"));
341
342    pcb = memp_malloc(MEMP_RAW_PCB);
343    /* could allocate RAW PCB? */
344    if (pcb != NULL) {
345        /* initialize PCB to all zeroes */
346        memset(pcb, 0, sizeof(struct raw_pcb));
347        pcb->protocol = proto;
348        pcb->ttl = RAW_TTL;
349        pcb->next = raw_pcbs;
350        raw_pcbs = pcb;
351    }
352    return pcb;
353}
354
355#endif                          /* LWIP_RAW */
356