ReactOS  0.4.15-dev-1397-g19779b3
icmp.c
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1 
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_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 #include "lwip/snmp.h"
52 
53 #include <string.h>
54 
58 #ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
59 #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
60 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
61 
62 /* The amount of data from the original packet to return in a dest-unreachable */
63 #define ICMP_DEST_UNREACH_DATASIZE 8
64 
65 static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
66 
76 void
77 icmp_input(struct pbuf *p, struct netif *inp)
78 {
79  u8_t type;
80 #ifdef LWIP_DEBUG
81  u8_t code;
82 #endif /* LWIP_DEBUG */
83  struct icmp_echo_hdr *iecho;
84  struct ip_hdr *iphdr;
85  s16_t hlen;
86 
87  ICMP_STATS_INC(icmp.recv);
89 
90 
91  iphdr = (struct ip_hdr *)p->payload;
92  hlen = IPH_HL(iphdr) * 4;
93  if (pbuf_header(p, -hlen) || (p->tot_len < sizeof(u16_t)*2)) {
94  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
95  goto lenerr;
96  }
97 
98  type = *((u8_t *)p->payload);
99 #ifdef LWIP_DEBUG
100  code = *(((u8_t *)p->payload)+1);
101 #endif /* LWIP_DEBUG */
102  switch (type) {
103  case ICMP_ER:
104  /* This is OK, echo reply might have been parsed by a raw PCB
105  (as obviously, an echo request has been sent, too). */
106  break;
107  case ICMP_ECHO:
108 #if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
109  {
110  int accepted = 1;
111 #if !LWIP_MULTICAST_PING
112  /* multicast destination address? */
114  accepted = 0;
115  }
116 #endif /* LWIP_MULTICAST_PING */
117 #if !LWIP_BROADCAST_PING
118  /* broadcast destination address? */
120  accepted = 0;
121  }
122 #endif /* LWIP_BROADCAST_PING */
123  /* broadcast or multicast destination address not acceptd? */
124  if (!accepted) {
125  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
126  ICMP_STATS_INC(icmp.err);
127  pbuf_free(p);
128  return;
129  }
130  }
131 #endif /* !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */
132  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
133  if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
134  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
135  goto lenerr;
136  }
137  if (inet_chksum_pbuf(p) != 0) {
138  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
139  pbuf_free(p);
140  ICMP_STATS_INC(icmp.chkerr);
142  return;
143  }
144 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
146  /* p is not big enough to contain link headers
147  * allocate a new one and copy p into it
148  */
149  struct pbuf *r;
150  /* switch p->payload to ip header */
151  if (pbuf_header(p, hlen)) {
152  LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
153  goto memerr;
154  }
155  /* allocate new packet buffer with space for link headers */
156  r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
157  if (r == NULL) {
158  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
159  goto memerr;
160  }
161  LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
162  (r->len >= hlen + sizeof(struct icmp_echo_hdr)));
163  /* copy the whole packet including ip header */
164  if (pbuf_copy(r, p) != ERR_OK) {
165  LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
166  goto memerr;
167  }
168  iphdr = (struct ip_hdr *)r->payload;
169  /* switch r->payload back to icmp header */
170  if (pbuf_header(r, -hlen)) {
171  LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
172  goto memerr;
173  }
174  /* free the original p */
175  pbuf_free(p);
176  /* we now have an identical copy of p that has room for link headers */
177  p = r;
178  } else {
179  /* restore p->payload to point to icmp header */
181  LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
182  goto memerr;
183  }
184  }
185 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
186  /* At this point, all checks are OK. */
187  /* We generate an answer by switching the dest and src ip addresses,
188  * setting the icmp type to ECHO_RESPONSE and updating the checksum. */
189  iecho = (struct icmp_echo_hdr *)p->payload;
190  ip_addr_copy(iphdr->src, *ip_current_dest_addr());
192  ICMPH_TYPE_SET(iecho, ICMP_ER);
193 #if CHECKSUM_GEN_ICMP
194  /* adjust the checksum */
195  if (iecho->chksum >= PP_HTONS(0xffffU - (ICMP_ECHO << 8))) {
196  iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
197  } else {
198  iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
199  }
200 #else /* CHECKSUM_GEN_ICMP */
201  iecho->chksum = 0;
202 #endif /* CHECKSUM_GEN_ICMP */
203 
204  /* Set the correct TTL and recalculate the header checksum. */
205  IPH_TTL_SET(iphdr, ICMP_TTL);
206  IPH_CHKSUM_SET(iphdr, 0);
207 #if CHECKSUM_GEN_IP
208  IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
209 #endif /* CHECKSUM_GEN_IP */
210 
211  ICMP_STATS_INC(icmp.xmit);
212  /* increase number of messages attempted to send */
214  /* increase number of echo replies attempted to send */
216 
217  if(pbuf_header(p, hlen)) {
218  LWIP_ASSERT("Can't move over header in packet", 0);
219  } else {
220  err_t ret;
221  /* send an ICMP packet, src addr is the dest addr of the curren packet */
223  ICMP_TTL, 0, IP_PROTO_ICMP, inp);
224  if (ret != ERR_OK) {
225  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
226  }
227  }
228  break;
229  default:
230  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
231  (s16_t)type, (s16_t)code));
232  ICMP_STATS_INC(icmp.proterr);
233  ICMP_STATS_INC(icmp.drop);
234  }
235  pbuf_free(p);
236  return;
237 lenerr:
238  pbuf_free(p);
239  ICMP_STATS_INC(icmp.lenerr);
241  return;
242 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
243 memerr:
244  pbuf_free(p);
245  ICMP_STATS_INC(icmp.err);
247  return;
248 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
249 }
250 
260 void
261 icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
262 {
263  icmp_send_response(p, ICMP_DUR, t);
264 }
265 
266 #if IP_FORWARD || IP_REASSEMBLY
267 
274 void
275 icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
276 {
277  icmp_send_response(p, ICMP_TE, t);
278 }
279 
280 #endif /* IP_FORWARD || IP_REASSEMBLY */
281 
290 static void
291 icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
292 {
293  struct pbuf *q;
294  struct ip_hdr *iphdr;
295  /* we can use the echo header here */
296  struct icmp_echo_hdr *icmphdr;
297  ip_addr_t iphdr_src;
298 
299  /* ICMP header + IP header + 8 bytes of data */
300  q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
301  PBUF_RAM);
302  if (q == NULL) {
303  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
304  return;
305  }
306  LWIP_ASSERT("check that first pbuf can hold icmp message",
307  (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
308 
309  iphdr = (struct ip_hdr *)p->payload;
310  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
311  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
312  LWIP_DEBUGF(ICMP_DEBUG, (" to "));
313  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
314  LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
315 
316  icmphdr = (struct icmp_echo_hdr *)q->payload;
317  icmphdr->type = type;
318  icmphdr->code = code;
319  icmphdr->id = 0;
320  icmphdr->seqno = 0;
321 
322  /* copy fields from original packet */
323  SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
324  IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
325 
326  /* calculate checksum */
327  icmphdr->chksum = 0;
328  icmphdr->chksum = inet_chksum(icmphdr, q->len);
329  ICMP_STATS_INC(icmp.xmit);
330  /* increase number of messages attempted to send */
332  /* increase number of destination unreachable messages attempted to send */
334  ip_addr_copy(iphdr_src, iphdr->src);
335  ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP);
336  pbuf_free(q);
337 }
338 
339 #endif /* LWIP_ICMP */
#define ip_addr_copy(dest, src)
Definition: ip_addr.h:162
#define SMEMCPY(dst, src, len)
Definition: opt.h:92
#define snmp_inc_icmpinmsgs()
Definition: snmp.h:284
#define S16_F
Definition: cc.h:37
GLdouble GLdouble GLdouble r
Definition: gl.h:2055
icmp_dur_type
Definition: icmp.h:56
#define IP_PROTO_ICMP
Definition: ip.h:52
#define ICMPH_TYPE_SET(hdr, t)
Definition: icmp.h:95
#define IPH_TTL_SET(hdr, ttl)
Definition: ip.h:161
#define ICMP_TTL
Definition: opt.h:637
u8_t pbuf_header(struct pbuf *p, s16_t header_size_increment)
Definition: pbuf.c:511
GLdouble GLdouble t
Definition: gl.h:2047
typedefPACK_STRUCT_END struct ip_addr ip_addr_t
Definition: ip_addr.h:64
#define PBUF_IP_HLEN
Definition: pbuf.h:48
#define ICMP_STATS_INC(x)
Definition: stats.h:187
#define LWIP_ASSERT(message, assertion)
Definition: debug.h:66
struct pbuf * pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
Definition: pbuf.c:207
#define snmp_inc_icmpoutechoreps()
Definition: snmp.h:305
Definition: pbuf.h:58
ip_addr_t current_iphdr_dest
Definition: ip.c:109
#define ip_addr_isbroadcast(ipaddr, netif)
Definition: ip_addr.h:202
icmp_te_type
Definition: icmp.h:65
#define snmp_inc_icmpoutmsgs()
Definition: snmp.h:297
#define ip_current_src_addr()
Definition: ip.h:200
Definition: pbuf.h:53
Definition: ip_icmp.h:52
#define IP_HDRINCL
Definition: ws2ipdef.h:28
#define ICMP_TE
Definition: icmp.h:49
u16_t inet_chksum_pbuf(struct pbuf *p)
Definition: inet_chksum.c:409
u8_t pbuf_free(struct pbuf *p)
Definition: pbuf.c:618
s8_t err_t
Definition: err.h:47
#define snmp_inc_icmpouttimeexcds()
Definition: snmp.h:300
#define IP_HLEN
Definition: ip.h:50
err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from)
Definition: pbuf.c:852
#define LWIP_DEBUGF(debug, message)
Definition: debug.h:95
#define PP_HTONS(x)
Definition: def.h:88
err_t ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, u8_t ttl, u8_t tos, u8_t proto, struct netif *netif)
Definition: ip.c:641
u16_t inet_chksum(void *dataptr, u16_t len)
Definition: inet_chksum.c:396
#define U16_F
Definition: cc.h:36
#define ERR_OK
Definition: err.h:52
if(!(yy_init))
Definition: macro.lex.yy.c:714
#define ip_addr_ismulticast(addr1)
Definition: ip_addr.h:208
Definition: pbuf.h:79
#define ICMP_ER
Definition: icmp.h:44
#define ip_addr_debug_print(debug, ipaddr)
Definition: ip_addr.h:212
Definition: netif.h:136
GLdouble GLdouble GLdouble GLdouble q
Definition: gl.h:2063
int ret
struct ip_addr src dest
Definition: ip.h:96
Definition: inflate.c:139
int code
Definition: main.c:75
err_t ip_output(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, u8_t ttl, u8_t tos, u8_t proto)
Definition: ip.c:818
Definition: ip.h:116
#define IPH_HL(hdr)
Definition: ip.h:147
#define snmp_inc_icmpinerrors()
Definition: snmp.h:285
unsigned char u8_t
Definition: cc.h:23
#define NULL
Definition: types.h:112
#define ICMP_ECHO
Definition: ip_icmp.h:157
Definition: pbuf.h:52
#define IPH_CHKSUM_SET(hdr, chksum)
Definition: ip.h:163
#define ICMP_DEBUG
Definition: opt.h:1940
unsigned short u16_t
Definition: cc.h:24
GLuint GLuint GLsizei GLenum type
Definition: gl.h:1545
#define PBUF_LINK_HLEN
Definition: opt.h:1095
GLfloat GLfloat p
Definition: glext.h:8902
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Definition: ip.h:202
signed short s16_t
Definition: cc.h:29
static void accepted(enum accept_stat, struct rpc_err *)
Definition: rpc_prot.c:280
#define ICMP_DUR
Definition: icmp.h:45