BadVPN – Blame information for rev 1
?pathlinks?
Rev | Author | Line No. | Line |
---|---|---|---|
1 | office | 1 | /** |
2 | * @file |
||
3 | * ICMP - Internet Control Message Protocol |
||
4 | * |
||
5 | */ |
||
6 | |||
7 | /* |
||
8 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
||
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: Adam Dunkels <adam@sics.se> |
||
36 | * |
||
37 | */ |
||
38 | |||
39 | /* Some ICMP messages should be passed to the transport protocols. This |
||
40 | is not implemented. */ |
||
41 | |||
42 | #include "lwip/opt.h" |
||
43 | |||
44 | #if LWIP_IPV4 && LWIP_ICMP /* don't build if not configured for use in lwipopts.h */ |
||
45 | |||
46 | #include "lwip/icmp.h" |
||
47 | #include "lwip/inet_chksum.h" |
||
48 | #include "lwip/ip.h" |
||
49 | #include "lwip/def.h" |
||
50 | #include "lwip/stats.h" |
||
51 | |||
52 | #include <string.h> |
||
53 | |||
54 | #ifdef LWIP_HOOK_FILENAME |
||
55 | #include LWIP_HOOK_FILENAME |
||
56 | #endif |
||
57 | |||
58 | /** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be |
||
59 | * used to modify and send a response packet (and to 1 if this is not the case, |
||
60 | * e.g. when link header is stripped off when receiving) */ |
||
61 | #ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN |
||
62 | #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1 |
||
63 | #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ |
||
64 | |||
65 | /* The amount of data from the original packet to return in a dest-unreachable */ |
||
66 | #define ICMP_DEST_UNREACH_DATASIZE 8 |
||
67 | |||
68 | static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code); |
||
69 | |||
70 | /** |
||
71 | * Processes ICMP input packets, called from ip_input(). |
||
72 | * |
||
73 | * Currently only processes icmp echo requests and sends |
||
74 | * out the echo response. |
||
75 | * |
||
76 | * @param p the icmp echo request packet, p->payload pointing to the icmp header |
||
77 | * @param inp the netif on which this packet was received |
||
78 | */ |
||
79 | void |
||
80 | icmp_input(struct pbuf *p, struct netif *inp) |
||
81 | { |
||
82 | u8_t type; |
||
83 | #ifdef LWIP_DEBUG |
||
84 | u8_t code; |
||
85 | #endif /* LWIP_DEBUG */ |
||
86 | struct icmp_echo_hdr *iecho; |
||
87 | const struct ip_hdr *iphdr_in; |
||
88 | u16_t hlen; |
||
89 | const ip4_addr_t *src; |
||
90 | |||
91 | ICMP_STATS_INC(icmp.recv); |
||
92 | MIB2_STATS_INC(mib2.icmpinmsgs); |
||
93 | |||
94 | iphdr_in = ip4_current_header(); |
||
95 | hlen = IPH_HL_BYTES(iphdr_in); |
||
96 | if (hlen < IP_HLEN) { |
||
97 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short IP header (%"S16_F" bytes) received\n", hlen)); |
||
98 | goto lenerr; |
||
99 | } |
||
100 | if (p->len < sizeof(u16_t) * 2) { |
||
101 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len)); |
||
102 | goto lenerr; |
||
103 | } |
||
104 | |||
105 | type = *((u8_t *)p->payload); |
||
106 | #ifdef LWIP_DEBUG |
||
107 | code = *(((u8_t *)p->payload) + 1); |
||
108 | /* if debug is enabled but debug statement below is somehow disabled: */ |
||
109 | LWIP_UNUSED_ARG(code); |
||
110 | #endif /* LWIP_DEBUG */ |
||
111 | switch (type) { |
||
112 | case ICMP_ER: |
||
113 | /* This is OK, echo reply might have been parsed by a raw PCB |
||
114 | (as obviously, an echo request has been sent, too). */ |
||
115 | MIB2_STATS_INC(mib2.icmpinechoreps); |
||
116 | break; |
||
117 | case ICMP_ECHO: |
||
118 | MIB2_STATS_INC(mib2.icmpinechos); |
||
119 | src = ip4_current_dest_addr(); |
||
120 | /* multicast destination address? */ |
||
121 | if (ip4_addr_ismulticast(ip4_current_dest_addr())) { |
||
122 | #if LWIP_MULTICAST_PING |
||
123 | /* For multicast, use address of receiving interface as source address */ |
||
124 | src = netif_ip4_addr(inp); |
||
125 | #else /* LWIP_MULTICAST_PING */ |
||
126 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast pings\n")); |
||
127 | goto icmperr; |
||
128 | #endif /* LWIP_MULTICAST_PING */ |
||
129 | } |
||
130 | /* broadcast destination address? */ |
||
131 | if (ip4_addr_isbroadcast(ip4_current_dest_addr(), ip_current_netif())) { |
||
132 | #if LWIP_BROADCAST_PING |
||
133 | /* For broadcast, use address of receiving interface as source address */ |
||
134 | src = netif_ip4_addr(inp); |
||
135 | #else /* LWIP_BROADCAST_PING */ |
||
136 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n")); |
||
137 | goto icmperr; |
||
138 | #endif /* LWIP_BROADCAST_PING */ |
||
139 | } |
||
140 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n")); |
||
141 | if (p->tot_len < sizeof(struct icmp_echo_hdr)) { |
||
142 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n")); |
||
143 | goto lenerr; |
||
144 | } |
||
145 | #if CHECKSUM_CHECK_ICMP |
||
146 | IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP) { |
||
147 | if (inet_chksum_pbuf(p) != 0) { |
||
148 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n")); |
||
149 | pbuf_free(p); |
||
150 | ICMP_STATS_INC(icmp.chkerr); |
||
151 | MIB2_STATS_INC(mib2.icmpinerrors); |
||
152 | return; |
||
153 | } |
||
154 | } |
||
155 | #endif |
||
156 | #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN |
||
157 | if (pbuf_add_header(p, hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN)) { |
||
158 | /* p is not big enough to contain link headers |
||
159 | * allocate a new one and copy p into it |
||
160 | */ |
||
161 | struct pbuf *r; |
||
162 | u16_t alloc_len = (u16_t)(p->tot_len + hlen); |
||
163 | if (alloc_len < p->tot_len) { |
||
164 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed (tot_len overflow)\n")); |
||
165 | goto icmperr; |
||
166 | } |
||
167 | /* allocate new packet buffer with space for link headers */ |
||
168 | r = pbuf_alloc(PBUF_LINK, alloc_len, PBUF_RAM); |
||
169 | if (r == NULL) { |
||
170 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n")); |
||
171 | goto icmperr; |
||
172 | } |
||
173 | if (r->len < hlen + sizeof(struct icmp_echo_hdr)) { |
||
174 | LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("first pbuf cannot hold the ICMP header")); |
||
175 | pbuf_free(r); |
||
176 | goto icmperr; |
||
177 | } |
||
178 | /* copy the ip header */ |
||
179 | MEMCPY(r->payload, iphdr_in, hlen); |
||
180 | /* switch r->payload back to icmp header (cannot fail) */ |
||
181 | if (pbuf_remove_header(r, hlen)) { |
||
182 | LWIP_ASSERT("icmp_input: moving r->payload to icmp header failed\n", 0); |
||
183 | pbuf_free(r); |
||
184 | goto icmperr; |
||
185 | } |
||
186 | /* copy the rest of the packet without ip header */ |
||
187 | if (pbuf_copy(r, p) != ERR_OK) { |
||
188 | LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("icmp_input: copying to new pbuf failed")); |
||
189 | pbuf_free(r); |
||
190 | goto icmperr; |
||
191 | } |
||
192 | /* free the original p */ |
||
193 | pbuf_free(p); |
||
194 | /* we now have an identical copy of p that has room for link headers */ |
||
195 | p = r; |
||
196 | } else { |
||
197 | /* restore p->payload to point to icmp header (cannot fail) */ |
||
198 | if (pbuf_remove_header(p, hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN)) { |
||
199 | LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0); |
||
200 | goto icmperr; |
||
201 | } |
||
202 | } |
||
203 | #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ |
||
204 | /* At this point, all checks are OK. */ |
||
205 | /* We generate an answer by switching the dest and src ip addresses, |
||
206 | * setting the icmp type to ECHO_RESPONSE and updating the checksum. */ |
||
207 | iecho = (struct icmp_echo_hdr *)p->payload; |
||
208 | if (pbuf_add_header(p, hlen)) { |
||
209 | LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Can't move over header in packet")); |
||
210 | } else { |
||
211 | err_t ret; |
||
212 | struct ip_hdr *iphdr = (struct ip_hdr *)p->payload; |
||
213 | ip4_addr_copy(iphdr->src, *src); |
||
214 | ip4_addr_copy(iphdr->dest, *ip4_current_src_addr()); |
||
215 | ICMPH_TYPE_SET(iecho, ICMP_ER); |
||
216 | #if CHECKSUM_GEN_ICMP |
||
217 | IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP) { |
||
218 | /* adjust the checksum */ |
||
219 | if (iecho->chksum > PP_HTONS(0xffffU - (ICMP_ECHO << 8))) { |
||
220 | iecho->chksum = (u16_t)(iecho->chksum + PP_HTONS((u16_t)(ICMP_ECHO << 8)) + 1); |
||
221 | } else { |
||
222 | iecho->chksum = (u16_t)(iecho->chksum + PP_HTONS(ICMP_ECHO << 8)); |
||
223 | } |
||
224 | } |
||
225 | #if LWIP_CHECKSUM_CTRL_PER_NETIF |
||
226 | else { |
||
227 | iecho->chksum = 0; |
||
228 | } |
||
229 | #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */ |
||
230 | #else /* CHECKSUM_GEN_ICMP */ |
||
231 | iecho->chksum = 0; |
||
232 | #endif /* CHECKSUM_GEN_ICMP */ |
||
233 | |||
234 | /* Set the correct TTL and recalculate the header checksum. */ |
||
235 | IPH_TTL_SET(iphdr, ICMP_TTL); |
||
236 | IPH_CHKSUM_SET(iphdr, 0); |
||
237 | #if CHECKSUM_GEN_IP |
||
238 | IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_IP) { |
||
239 | IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, hlen)); |
||
240 | } |
||
241 | #endif /* CHECKSUM_GEN_IP */ |
||
242 | |||
243 | ICMP_STATS_INC(icmp.xmit); |
||
244 | /* increase number of messages attempted to send */ |
||
245 | MIB2_STATS_INC(mib2.icmpoutmsgs); |
||
246 | /* increase number of echo replies attempted to send */ |
||
247 | MIB2_STATS_INC(mib2.icmpoutechoreps); |
||
248 | |||
249 | /* send an ICMP packet */ |
||
250 | ret = ip4_output_if(p, src, LWIP_IP_HDRINCL, |
||
251 | ICMP_TTL, 0, IP_PROTO_ICMP, inp); |
||
252 | if (ret != ERR_OK) { |
||
253 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %s\n", lwip_strerr(ret))); |
||
254 | } |
||
255 | } |
||
256 | break; |
||
257 | default: |
||
258 | if (type == ICMP_DUR) { |
||
259 | MIB2_STATS_INC(mib2.icmpindestunreachs); |
||
260 | } else if (type == ICMP_TE) { |
||
261 | MIB2_STATS_INC(mib2.icmpintimeexcds); |
||
262 | } else if (type == ICMP_PP) { |
||
263 | MIB2_STATS_INC(mib2.icmpinparmprobs); |
||
264 | } else if (type == ICMP_SQ) { |
||
265 | MIB2_STATS_INC(mib2.icmpinsrcquenchs); |
||
266 | } else if (type == ICMP_RD) { |
||
267 | MIB2_STATS_INC(mib2.icmpinredirects); |
||
268 | } else if (type == ICMP_TS) { |
||
269 | MIB2_STATS_INC(mib2.icmpintimestamps); |
||
270 | } else if (type == ICMP_TSR) { |
||
271 | MIB2_STATS_INC(mib2.icmpintimestampreps); |
||
272 | } else if (type == ICMP_AM) { |
||
273 | MIB2_STATS_INC(mib2.icmpinaddrmasks); |
||
274 | } else if (type == ICMP_AMR) { |
||
275 | MIB2_STATS_INC(mib2.icmpinaddrmaskreps); |
||
276 | } |
||
277 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n", |
||
278 | (s16_t)type, (s16_t)code)); |
||
279 | ICMP_STATS_INC(icmp.proterr); |
||
280 | ICMP_STATS_INC(icmp.drop); |
||
281 | } |
||
282 | pbuf_free(p); |
||
283 | return; |
||
284 | lenerr: |
||
285 | pbuf_free(p); |
||
286 | ICMP_STATS_INC(icmp.lenerr); |
||
287 | MIB2_STATS_INC(mib2.icmpinerrors); |
||
288 | return; |
||
289 | #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN || !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING |
||
290 | icmperr: |
||
291 | pbuf_free(p); |
||
292 | ICMP_STATS_INC(icmp.err); |
||
293 | MIB2_STATS_INC(mib2.icmpinerrors); |
||
294 | return; |
||
295 | #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN || !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */ |
||
296 | } |
||
297 | |||
298 | /** |
||
299 | * Send an icmp 'destination unreachable' packet, called from ip_input() if |
||
300 | * the transport layer protocol is unknown and from udp_input() if the local |
||
301 | * port is not bound. |
||
302 | * |
||
303 | * @param p the input packet for which the 'unreachable' should be sent, |
||
304 | * p->payload pointing to the IP header |
||
305 | * @param t type of the 'unreachable' packet |
||
306 | */ |
||
307 | void |
||
308 | icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t) |
||
309 | { |
||
310 | MIB2_STATS_INC(mib2.icmpoutdestunreachs); |
||
311 | icmp_send_response(p, ICMP_DUR, t); |
||
312 | } |
||
313 | |||
314 | #if IP_FORWARD || IP_REASSEMBLY |
||
315 | /** |
||
316 | * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0. |
||
317 | * |
||
318 | * @param p the input packet for which the 'time exceeded' should be sent, |
||
319 | * p->payload pointing to the IP header |
||
320 | * @param t type of the 'time exceeded' packet |
||
321 | */ |
||
322 | void |
||
323 | icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t) |
||
324 | { |
||
325 | MIB2_STATS_INC(mib2.icmpouttimeexcds); |
||
326 | icmp_send_response(p, ICMP_TE, t); |
||
327 | } |
||
328 | |||
329 | #endif /* IP_FORWARD || IP_REASSEMBLY */ |
||
330 | |||
331 | /** |
||
332 | * Send an icmp packet in response to an incoming packet. |
||
333 | * |
||
334 | * @param p the input packet for which the 'unreachable' should be sent, |
||
335 | * p->payload pointing to the IP header |
||
336 | * @param type Type of the ICMP header |
||
337 | * @param code Code of the ICMP header |
||
338 | */ |
||
339 | static void |
||
340 | icmp_send_response(struct pbuf *p, u8_t type, u8_t code) |
||
341 | { |
||
342 | struct pbuf *q; |
||
343 | struct ip_hdr *iphdr; |
||
344 | /* we can use the echo header here */ |
||
345 | struct icmp_echo_hdr *icmphdr; |
||
346 | ip4_addr_t iphdr_src; |
||
347 | struct netif *netif; |
||
348 | |||
349 | /* increase number of messages attempted to send */ |
||
350 | MIB2_STATS_INC(mib2.icmpoutmsgs); |
||
351 | |||
352 | /* ICMP header + IP header + 8 bytes of data */ |
||
353 | q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE, |
||
354 | PBUF_RAM); |
||
355 | if (q == NULL) { |
||
356 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n")); |
||
357 | MIB2_STATS_INC(mib2.icmpouterrors); |
||
358 | return; |
||
359 | } |
||
360 | LWIP_ASSERT("check that first pbuf can hold icmp message", |
||
361 | (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE))); |
||
362 | |||
363 | iphdr = (struct ip_hdr *)p->payload; |
||
364 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from ")); |
||
365 | ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->src); |
||
366 | LWIP_DEBUGF(ICMP_DEBUG, (" to ")); |
||
367 | ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->dest); |
||
368 | LWIP_DEBUGF(ICMP_DEBUG, ("\n")); |
||
369 | |||
370 | icmphdr = (struct icmp_echo_hdr *)q->payload; |
||
371 | icmphdr->type = type; |
||
372 | icmphdr->code = code; |
||
373 | icmphdr->id = 0; |
||
374 | icmphdr->seqno = 0; |
||
375 | |||
376 | /* copy fields from original packet */ |
||
377 | SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload, |
||
378 | IP_HLEN + ICMP_DEST_UNREACH_DATASIZE); |
||
379 | |||
380 | ip4_addr_copy(iphdr_src, iphdr->src); |
||
381 | #ifdef LWIP_HOOK_IP4_ROUTE_SRC |
||
382 | { |
||
383 | ip4_addr_t iphdr_dst; |
||
384 | ip4_addr_copy(iphdr_dst, iphdr->dest); |
||
385 | netif = ip4_route_src(&iphdr_src, &iphdr_dst); |
||
386 | } |
||
387 | #else |
||
388 | netif = ip4_route(&iphdr_src); |
||
389 | #endif |
||
390 | if (netif != NULL) { |
||
391 | /* calculate checksum */ |
||
392 | icmphdr->chksum = 0; |
||
393 | #if CHECKSUM_GEN_ICMP |
||
394 | IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP) { |
||
395 | icmphdr->chksum = inet_chksum(icmphdr, q->len); |
||
396 | } |
||
397 | #endif |
||
398 | ICMP_STATS_INC(icmp.xmit); |
||
399 | ip4_output_if(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP, netif); |
||
400 | } |
||
401 | pbuf_free(q); |
||
402 | } |
||
403 | |||
404 | #endif /* LWIP_IPV4 && LWIP_ICMP */ |