1 /**
2 * @file
3 *
4 * IPv6 version of ICMP, as per RFC 4443.
5 */
6
7 /*
8 * Copyright (c) 2010 Inico Technologies Ltd.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without modification,
12 * are permitted provided that the following conditions are met:
13 *
14 * 1. Redistributions of source code must retain the above copyright notice,
15 * this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright notice,
17 * this list of conditions and the following disclaimer in the documentation
18 * and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
31 * OF SUCH DAMAGE.
32 *
33 * This file is part of the lwIP TCP/IP stack.
34 *
35 * Author: Ivan Delamer <[email protected]>
36 *
37 *
38 * Please coordinate changes and requests with Ivan Delamer
39 * <[email protected]>
40 */
41
42 #include "lwip/opt.h"
43
44 #if LWIP_ICMP6 && LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
45
46 #include "lwip/icmp6.h"
47 #include "lwip/prot/icmp6.h"
48 #include "lwip/ip6.h"
49 #include "lwip/ip6_addr.h"
50 #include "lwip/inet_chksum.h"
51 #include "lwip/pbuf.h"
52 #include "lwip/netif.h"
53 #include "lwip/nd6.h"
54 #include "lwip/mld6.h"
55 #include "lwip/ip.h"
56 #include "lwip/stats.h"
57
58 #include <string.h>
59
60 #ifndef LWIP_ICMP6_DATASIZE
61 #define LWIP_ICMP6_DATASIZE 8
62 #endif
63 #if LWIP_ICMP6_DATASIZE == 0
64 #define LWIP_ICMP6_DATASIZE 8
65 #endif
66
67 /* Forward declarations */
68 static void icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type);
69
70
71 /**
72 * Process an input ICMPv6 message. Called by ip6_input.
73 *
74 * Will generate a reply for echo requests. Other messages are forwarded
75 * to nd6_input, or mld6_input.
76 *
77 * @param p the mld packet, p->payload pointing to the icmpv6 header
78 * @param inp the netif on which this packet was received
79 */
80 void
icmp6_input(struct pbuf * p,struct netif * inp)81 icmp6_input(struct pbuf *p, struct netif *inp)
82 {
83 struct icmp6_hdr *icmp6hdr;
84 struct pbuf *r;
85 const ip6_addr_t *reply_src;
86
87 ICMP6_STATS_INC(icmp6.recv);
88
89 /* Check that ICMPv6 header fits in payload */
90 if (p->len < sizeof(struct icmp6_hdr)) {
91 /* drop short packets */
92 pbuf_free(p);
93 ICMP6_STATS_INC(icmp6.lenerr);
94 ICMP6_STATS_INC(icmp6.drop);
95 return;
96 }
97
98 icmp6hdr = (struct icmp6_hdr *)p->payload;
99
100 #if CHECKSUM_CHECK_ICMP6
101 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP6) {
102 if (ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->tot_len, ip6_current_src_addr(),
103 ip6_current_dest_addr()) != 0) {
104 /* Checksum failed */
105 pbuf_free(p);
106 ICMP6_STATS_INC(icmp6.chkerr);
107 ICMP6_STATS_INC(icmp6.drop);
108 return;
109 }
110 }
111 #endif /* CHECKSUM_CHECK_ICMP6 */
112
113 switch (icmp6hdr->type) {
114 case ICMP6_TYPE_NA: /* Neighbor advertisement */
115 case ICMP6_TYPE_NS: /* Neighbor solicitation */
116 case ICMP6_TYPE_RA: /* Router advertisement */
117 case ICMP6_TYPE_RD: /* Redirect */
118 case ICMP6_TYPE_PTB: /* Packet too big */
119 nd6_input(p, inp);
120 return;
121 break;
122 case ICMP6_TYPE_RS:
123 #if LWIP_IPV6_FORWARD
124 /* @todo implement router functionality */
125 #endif
126 break;
127 #if LWIP_IPV6_MLD
128 case ICMP6_TYPE_MLQ:
129 case ICMP6_TYPE_MLR:
130 case ICMP6_TYPE_MLD:
131 mld6_input(p, inp);
132 return;
133 break;
134 #endif
135 case ICMP6_TYPE_EREQ:
136 #if !LWIP_MULTICAST_PING
137 /* multicast destination address? */
138 if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
139 /* drop */
140 pbuf_free(p);
141 ICMP6_STATS_INC(icmp6.drop);
142 return;
143 }
144 #endif /* LWIP_MULTICAST_PING */
145
146 /* Allocate reply. */
147 r = pbuf_alloc(PBUF_IP, p->tot_len, PBUF_RAM);
148 if (r == NULL) {
149 /* drop */
150 pbuf_free(p);
151 ICMP6_STATS_INC(icmp6.memerr);
152 return;
153 }
154
155 /* Copy echo request. */
156 if (pbuf_copy(r, p) != ERR_OK) {
157 /* drop */
158 pbuf_free(p);
159 pbuf_free(r);
160 ICMP6_STATS_INC(icmp6.err);
161 return;
162 }
163
164 /* Determine reply source IPv6 address. */
165 #if LWIP_MULTICAST_PING
166 if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
167 reply_src = ip_2_ip6(ip6_select_source_address(inp, ip6_current_src_addr()));
168 if (reply_src == NULL) {
169 /* drop */
170 pbuf_free(p);
171 pbuf_free(r);
172 ICMP6_STATS_INC(icmp6.rterr);
173 return;
174 }
175 }
176 else
177 #endif /* LWIP_MULTICAST_PING */
178 {
179 reply_src = ip6_current_dest_addr();
180 }
181
182 /* Set fields in reply. */
183 ((struct icmp6_echo_hdr *)(r->payload))->type = ICMP6_TYPE_EREP;
184 ((struct icmp6_echo_hdr *)(r->payload))->chksum = 0;
185 #if CHECKSUM_GEN_ICMP6
186 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP6) {
187 ((struct icmp6_echo_hdr *)(r->payload))->chksum = ip6_chksum_pseudo(r,
188 IP6_NEXTH_ICMP6, r->tot_len, reply_src, ip6_current_src_addr());
189 }
190 #endif /* CHECKSUM_GEN_ICMP6 */
191
192 /* Send reply. */
193 ICMP6_STATS_INC(icmp6.xmit);
194 ip6_output_if(r, reply_src, ip6_current_src_addr(),
195 LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, inp);
196 pbuf_free(r);
197
198 break;
199 default:
200 ICMP6_STATS_INC(icmp6.proterr);
201 ICMP6_STATS_INC(icmp6.drop);
202 break;
203 }
204
205 pbuf_free(p);
206 }
207
208
209 /**
210 * Send an icmpv6 'destination unreachable' packet.
211 *
212 * @param p the input packet for which the 'unreachable' should be sent,
213 * p->payload pointing to the IPv6 header
214 * @param c ICMPv6 code for the unreachable type
215 */
216 void
icmp6_dest_unreach(struct pbuf * p,enum icmp6_dur_code c)217 icmp6_dest_unreach(struct pbuf *p, enum icmp6_dur_code c)
218 {
219 icmp6_send_response(p, c, 0, ICMP6_TYPE_DUR);
220 }
221
222 /**
223 * Send an icmpv6 'packet too big' packet.
224 *
225 * @param p the input packet for which the 'packet too big' should be sent,
226 * p->payload pointing to the IPv6 header
227 * @param mtu the maximum mtu that we can accept
228 */
229 void
icmp6_packet_too_big(struct pbuf * p,u32_t mtu)230 icmp6_packet_too_big(struct pbuf *p, u32_t mtu)
231 {
232 icmp6_send_response(p, 0, mtu, ICMP6_TYPE_PTB);
233 }
234
235 /**
236 * Send an icmpv6 'time exceeded' packet.
237 *
238 * @param p the input packet for which the 'unreachable' should be sent,
239 * p->payload pointing to the IPv6 header
240 * @param c ICMPv6 code for the time exceeded type
241 */
242 void
icmp6_time_exceeded(struct pbuf * p,enum icmp6_te_code c)243 icmp6_time_exceeded(struct pbuf *p, enum icmp6_te_code c)
244 {
245 icmp6_send_response(p, c, 0, ICMP6_TYPE_TE);
246 }
247
248 /**
249 * Send an icmpv6 'parameter problem' packet.
250 *
251 * @param p the input packet for which the 'param problem' should be sent,
252 * p->payload pointing to the IP header
253 * @param c ICMPv6 code for the param problem type
254 * @param pointer the pointer to the byte where the parameter is found
255 */
256 void
icmp6_param_problem(struct pbuf * p,enum icmp6_pp_code c,u32_t pointer)257 icmp6_param_problem(struct pbuf *p, enum icmp6_pp_code c, u32_t pointer)
258 {
259 icmp6_send_response(p, c, pointer, ICMP6_TYPE_PP);
260 }
261
262 /**
263 * Send an ICMPv6 packet in response to an incoming packet.
264 *
265 * @param p the input packet for which the response should be sent,
266 * p->payload pointing to the IPv6 header
267 * @param code Code of the ICMPv6 header
268 * @param data Additional 32-bit parameter in the ICMPv6 header
269 * @param type Type of the ICMPv6 header
270 */
271 static void
icmp6_send_response(struct pbuf * p,u8_t code,u32_t data,u8_t type)272 icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type)
273 {
274 struct pbuf *q;
275 struct icmp6_hdr *icmp6hdr;
276 const ip6_addr_t *reply_src;
277 ip6_addr_t *reply_dest;
278 ip6_addr_t reply_src_local, reply_dest_local;
279 struct ip6_hdr *ip6hdr;
280 struct netif *netif;
281
282 /* ICMPv6 header + IPv6 header + data */
283 q = pbuf_alloc(PBUF_IP, sizeof(struct icmp6_hdr) + IP6_HLEN + LWIP_ICMP6_DATASIZE,
284 PBUF_RAM);
285 if (q == NULL) {
286 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMPv6 packet.\n"));
287 ICMP6_STATS_INC(icmp6.memerr);
288 return;
289 }
290 LWIP_ASSERT("check that first pbuf can hold icmp 6message",
291 (q->len >= (sizeof(struct icmp6_hdr) + IP6_HLEN + LWIP_ICMP6_DATASIZE)));
292
293 icmp6hdr = (struct icmp6_hdr *)q->payload;
294 icmp6hdr->type = type;
295 icmp6hdr->code = code;
296 icmp6hdr->data = data;
297
298 /* copy fields from original packet */
299 SMEMCPY((u8_t *)q->payload + sizeof(struct icmp6_hdr), (u8_t *)p->payload,
300 IP6_HLEN + LWIP_ICMP6_DATASIZE);
301
302 /* Get the destination address and netif for this ICMP message. */
303 if ((ip_current_netif() == NULL) ||
304 ((code == ICMP6_TE_FRAG) && (type == ICMP6_TYPE_TE))) {
305 /* Special case, as ip6_current_xxx is either NULL, or points
306 * to a different packet than the one that expired.
307 * We must use the addresses that are stored in the expired packet. */
308 ip6hdr = (struct ip6_hdr *)p->payload;
309 /* copy from packed address to aligned address */
310 ip6_addr_copy(reply_dest_local, ip6hdr->src);
311 ip6_addr_copy(reply_src_local, ip6hdr->dest);
312 reply_dest = &reply_dest_local;
313 reply_src = &reply_src_local;
314 netif = ip6_route(reply_src, reply_dest);
315 if (netif == NULL) {
316 /* drop */
317 pbuf_free(q);
318 ICMP6_STATS_INC(icmp6.rterr);
319 return;
320 }
321 }
322 else {
323 netif = ip_current_netif();
324 reply_dest = ip6_current_src_addr();
325
326 /* Select an address to use as source. */
327 reply_src = ip_2_ip6(ip6_select_source_address(netif, reply_dest));
328 if (reply_src == NULL) {
329 /* drop */
330 pbuf_free(q);
331 ICMP6_STATS_INC(icmp6.rterr);
332 return;
333 }
334 }
335
336 /* calculate checksum */
337 icmp6hdr->chksum = 0;
338 #if CHECKSUM_GEN_ICMP6
339 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
340 icmp6hdr->chksum = ip6_chksum_pseudo(q, IP6_NEXTH_ICMP6, q->tot_len,
341 reply_src, reply_dest);
342 }
343 #endif /* CHECKSUM_GEN_ICMP6 */
344
345 ICMP6_STATS_INC(icmp6.xmit);
346 ip6_output_if(q, reply_src, reply_dest, LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
347 pbuf_free(q);
348 }
349
350 #endif /* LWIP_ICMP6 && LWIP_IPV6 */
351