FD.io VPP  v19.04-6-g6f05f72
Vector Packet Processing
icmp_proto.c
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1 /*
2  *------------------------------------------------------------------
3  * Copyright (c) 2017 Cisco and/or its affiliates.
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at:
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *------------------------------------------------------------------
16  */
17 
18 #include <stdint.h>
19 #include <net/if.h>
20 #include <sys/types.h>
21 #include <fcntl.h>
22 #include <sys/ioctl.h>
23 #include <sys/socket.h>
24 #include <sys/un.h>
25 #include <sys/uio.h>
26 #include <sys/mman.h>
27 #include <sys/prctl.h>
28 #include <inttypes.h>
29 #include <string.h>
30 #include <stdio.h>
31 #include <netdb.h>
32 #include <linux/ip.h>
33 #include <linux/icmp.h>
34 #include <arpa/inet.h>
35 #include <stdlib.h>
36 #include <netinet/if_ether.h>
37 #include <net/if_arp.h>
38 #include <asm/byteorder.h>
39 #include <byteswap.h>
40 #include <assert.h>
41 
42 #include <icmp_proto.h>
43 
44 static uint16_t
45 cksum (void *addr, ssize_t len)
46 {
47  char *data = (char *) addr;
48 
49  uint32_t acc = 0xffff;
50 
51  ssize_t i;
52  for (i = 0; (i + 1) < len; i += 2)
53  {
54  uint16_t word;
55  memcpy (&word, data + i, 2);
56  acc += ntohs (word);
57  if (acc > 0xffff)
58  acc -= 0xffff;
59  }
60 
61  if (len & 1)
62  {
63  uint16_t word = 0;
64  memcpy (&word, data + len - 1, 1);
65  acc += ntohs (word);
66  if (acc > 0xffff)
67  acc -= 0xffff;
68  }
69  return htons (~acc);
70 }
71 
72 int
73 print_packet (void *pck)
74 {
75  if (pck == NULL)
76  {
77  printf ("ICMP_PROTO: no data\n");
78  return -1;
79  }
80  struct iphdr *ip;
81  struct icmphdr *icmp;
82  ip = (struct iphdr *) pck;
83  icmp = (struct icmphdr *) (pck + sizeof (struct iphdr));
84  printf ("received packet:\n");
85  printf ("\tiphdr:\n");
86  printf ("\t\tihl: %u\n\t\tversion: %u\n\t\tlen: %u\n\t\tid: %u\n",
87  ip->ihl, ip->version, __bswap_16 (ip->tot_len), ip->id);
88  printf ("\t\tprotocol: %u\n", ip->protocol);
89 
90  printf ("\t\tsaddr: ");
91  int i;
92  for (i = 0; i < 4; i++)
93  {
94  printf ("%u.", ((uint8_t *) & ip->saddr)[i]);
95  }
96  printf ("\n");
97 
98  printf ("\t\tdaddr: ");
99  for (i = 0; i < 4; i++)
100  {
101  printf ("%u.", ((uint8_t *) & ip->daddr)[i]);
102  }
103  printf ("\n");
104  printf ("\ticmphdr:\n");
105  printf ("\t\ttype: %s\n",
106  (icmp->type == ICMP_ECHO) ? "ICMP_ECHO" : "ICMP_ECHOREPLY");
107 
108  return 0;
109 }
110 
111 static ssize_t
112 resolve_arp (void *arp)
113 {
114  struct arphdr *resp = (struct arphdr *) arp;
115 
116  resp->ar_hrd = __bswap_16 (ARPHRD_ETHER);
117 
118  resp->ar_pro = __bswap_16 (0x0800);
119 
120  resp->ar_hln = 6;
121  resp->ar_pln = 4;
122 
123  resp->ar_op = __bswap_16 (ARPOP_REPLY);
124 
125  return sizeof (struct arphdr);
126 }
127 
128 static ssize_t
129 resolve_eth_arp (struct ether_arp *eth_arp, void *eth_arp_resp,
130  uint8_t ip_addr[4])
131 {
132  struct ether_arp *resp = (struct ether_arp *) eth_arp_resp;
133 
134  resolve_arp (&resp->ea_hdr);
135 
136  memcpy (resp->arp_tha, eth_arp->arp_sha, 6);
137  memcpy (resp->arp_tpa, eth_arp->arp_spa, 4);
138 
139  memcpy (resp->arp_sha,
140  (((struct ether_header *) (eth_arp_resp -
141  sizeof (struct
142  ether_header)))->ether_shost),
143  6);
144 
145  memcpy (resp->arp_spa, ip_addr, 4);
146 
147  return sizeof (struct ether_arp);
148 }
149 
150 static ssize_t
151 resolve_eth (struct ether_header *eth, void *eth_resp)
152 {
153  struct ether_header *resp = (struct ether_header *) eth_resp;
154  memcpy (resp->ether_dhost, eth->ether_shost, 6);
155 
156  uint8_t hw_addr[6];
157  int i;
158  for (i = 0; i < 6; i++)
159  {
160  hw_addr[i] = 'a';
161  }
162  memcpy (resp->ether_shost, hw_addr, 6);
163 
164  resp->ether_type = eth->ether_type;
165 
166  return sizeof (struct ether_header);
167 }
168 
169 static ssize_t
170 resolve_ip (struct iphdr *ip, void *ip_resp, uint8_t ip_addr[4])
171 {
172  struct iphdr *resp = (struct iphdr *) ip_resp;
173  resp->ihl = 5;
174  resp->version = 4;
175  resp->tos = 0;
176  /*len updated later */
177  resp->tot_len = 0x0000;
178  resp->id = 0;
179  resp->frag_off = 0;
180  resp->ttl = 0x40;
181  resp->protocol = 1;
182  ((uint8_t *) & resp->saddr)[0] = ip_addr[0];
183  ((uint8_t *) & resp->saddr)[1] = ip_addr[1];
184  ((uint8_t *) & resp->saddr)[2] = ip_addr[2];
185  ((uint8_t *) & resp->saddr)[3] = ip_addr[3];
186  resp->daddr = ip->saddr;
187 
188  /* resp->check = cksum (resp, sizeof (struct iphdr)); */
189 
190  return sizeof (struct iphdr);
191 }
192 
193 static ssize_t
194 resolve_icmp (struct icmphdr *icmp, void *icmp_resp)
195 {
196  struct icmphdr *resp = (struct icmphdr *) icmp_resp;
197  resp->type = 0x00;
198  resp->code = 0;
199  resp->un.echo.id = icmp->un.echo.id;
200  resp->un.echo.sequence = icmp->un.echo.sequence;
201 
202  /*resp->checksum = cksum (resp, sizeof (struct icmphdr)); */
203 
204  return sizeof (struct icmphdr);
205 }
206 
207 int
208 resolve_packet (void *in_pck, ssize_t in_size,
209  void *out_pck, uint32_t * out_size, uint8_t ip_addr[4])
210 {
211  struct ether_header *eh;
212  struct ether_arp *eah;
213  struct iphdr *ip, *ip_out;
214  struct icmphdr *icmp;
215  *out_size = 0;
216 
217  if ((in_pck == NULL) || (out_pck == NULL))
218  return -1;
219 
220  eh = (struct ether_header *) in_pck;
221  *out_size = resolve_eth (eh, out_pck);
222 
223  if (eh->ether_type == 0x0608)
224  {
225  eah = (struct ether_arp *) (in_pck + *out_size);
226  *out_size += resolve_eth_arp (eah, out_pck + *out_size, ip_addr);
227 
228  }
229  else if (eh->ether_type == 0x0008)
230  {
231 #ifdef ICMP_DBG
232  print_packet (in_pck + *out_size);
233 #endif
234  ip = (struct iphdr *) (in_pck + *out_size);
235  ip_out = (struct iphdr *) (out_pck + *out_size);
236  *out_size += resolve_ip (ip, out_pck + *out_size, ip_addr);
237  if (ip->protocol == 1)
238  {
239  icmp = (struct icmphdr *) (in_pck + *out_size);
240  *out_size += resolve_icmp (icmp, out_pck + *out_size);
241  ((struct icmphdr *) (out_pck + *out_size -
242  sizeof (struct icmphdr)))->checksum =
243  cksum (out_pck + *out_size - sizeof (struct icmphdr),
244  sizeof (struct icmphdr));
245  /* payload */
246  memcpy (out_pck + *out_size, in_pck + *out_size,
247  in_size - *out_size);
248  *out_size = in_size;
249  ip_out->tot_len =
250  __bswap_16 (*out_size - sizeof (struct ether_header));
251  ip_out->check = cksum (ip_out, sizeof (struct iphdr));
252  }
253  }
254  return 0;
255 }
256 
257 static ssize_t
258 generate_eth (struct ether_header *eh, uint8_t hw_daddr[6])
259 {
260  uint8_t hw_addr[6];
261  int i;
262  for (i = 0; i < 6; i++)
263  {
264  hw_addr[i] = 'a';
265  }
266  memcpy (eh->ether_shost, hw_addr, 6);
267  memcpy (eh->ether_dhost, hw_daddr, 6);
268 
269  eh->ether_type = 0x0008;
270 
271  return sizeof (struct ether_header);
272 }
273 
274 static ssize_t
275 generate_ip (struct iphdr *ip, uint8_t saddr[4], uint8_t daddr[4])
276 {
277  ip->ihl = 5;
278  ip->version = 4;
279  ip->tos = 0;
280  /*len updated later */
281  ip->tot_len = 0x5400;
282  ip->id = 0;
283  ip->frag_off = 0;
284  ip->ttl = 0x40;
285  ip->protocol = 1;
286  /* saddr */
287  ((uint8_t *) & ip->saddr)[0] = saddr[0];
288  ((uint8_t *) & ip->saddr)[1] = saddr[1];
289  ((uint8_t *) & ip->saddr)[2] = saddr[2];
290  ((uint8_t *) & ip->saddr)[3] = saddr[3];
291  /* daddr */
292  ((uint8_t *) & ip->daddr)[0] = daddr[0];
293  ((uint8_t *) & ip->daddr)[1] = daddr[1];
294  ((uint8_t *) & ip->daddr)[2] = daddr[2];
295  ((uint8_t *) & ip->daddr)[3] = daddr[3];
296 
297  ip->check = cksum (ip, sizeof (struct iphdr));
298 
299  return sizeof (struct iphdr);
300 }
301 
302 static ssize_t
303 generate_icmp (struct icmphdr *icmp, uint32_t seq)
304 {
305  icmp->type = ICMP_ECHO;
306  icmp->code = 0;
307  icmp->un.echo.id = 0;
308  icmp->un.echo.sequence = seq;
309 
310  return sizeof (struct icmphdr);
311 }
312 
313 int
314 generate_packet (void *pck, uint32_t * size, uint8_t saddr[4],
315  uint8_t daddr[4], uint8_t hw_daddr[6], uint32_t seq)
316 {
317  struct ether_header *eh;
318  struct iphdr *ip;
319  struct icmphdr *icmp;
320 
321  *size = 0;
322 
323  eh = (struct ether_header *) pck;
324  *size += generate_eth (eh, hw_daddr);
325 
326  ip = (struct iphdr *) (pck + *size);
327  *size += generate_ip (ip, saddr, daddr);
328 
329  icmp = (struct icmphdr *) (pck + *size);
330  *size += generate_icmp (icmp, seq);
331 
332  ((struct icmphdr *) (pck + *size - sizeof (struct icmphdr)))->checksum =
333  cksum (pck + *size - sizeof (struct icmphdr), sizeof (struct icmphdr));
334 
335  ip->tot_len = __bswap_16 (*size - sizeof (struct ether_header));
336  ip->check = 0;
337  ip->check = cksum (ip, sizeof (struct iphdr));
338 
339  return 0;
340 }
341 
342 int
343 generate_packet2 (void *pck, uint32_t * size, uint8_t saddr[4],
344  uint8_t daddr[4], uint8_t hw_daddr[6], uint32_t seq,
346 {
347  struct ether_header *eh;
348  struct iphdr *ip;
349  struct icmphdr *icmp;
350 
351  *size = 0;
352 
353  if (mode == ICMPR_FLOW_MODE_ETH)
354  {
355  eh = (struct ether_header *) pck;
356  *size += generate_eth (eh, hw_daddr);
357  }
358 
359  ip = (struct iphdr *) (pck + *size);
360  *size += generate_ip (ip, saddr, daddr);
361 
362  icmp = (struct icmphdr *) (pck + *size);
363  *size += generate_icmp (icmp, seq);
364 
365  ((struct icmphdr *) (pck + *size - sizeof (struct icmphdr)))->checksum =
366  cksum (pck + *size - sizeof (struct icmphdr), sizeof (struct icmphdr));
367 
368  ip->tot_len = __bswap_16 (*size - sizeof (struct ether_header));
369  ip->check = 0;
370  ip->check = cksum (ip, sizeof (struct iphdr));
371 
372  return 0;
373 }
374 
375 #define GET_HEADER(out,hdr,src,off) do { \
376  out = (hdr*)(src + off); \
377  off += sizeof (hdr); \
378  } while (0)
379 
380 int
381 resolve_packet2 (void *pck, uint32_t * size, uint8_t ip_addr[4])
382 {
383  struct ether_header *eh;
384  struct ether_arp *eah;
385  struct iphdr *ip;
386  struct icmphdr *icmp;
387  uint32_t offset = 0;
388 
389  if (pck == NULL)
390  return 0;
391 
392  GET_HEADER (eh, struct ether_header, pck, offset);
393 
394  memcpy (eh->ether_dhost, eh->ether_shost, 6);
395  memcpy (eh->ether_shost, "aaaaaa", 6);
396 
397  if (eh->ether_type == 0x0608)
398  {
399  GET_HEADER (eah, struct ether_arp, pck, offset);
400  struct arphdr *arp = &eah->ea_hdr;
401 
402  arp->ar_hrd = __bswap_16 (ARPHRD_ETHER);
403  arp->ar_pro = __bswap_16 (0x0800);
404 
405  arp->ar_hln = 6;
406  arp->ar_pln = 4;
407 
408  arp->ar_op = __bswap_16 (ARPOP_REPLY);
409 
410  memcpy (eah->arp_tha, eah->arp_sha, 6);
411  memcpy (eah->arp_tpa, eah->arp_spa, 4);
412 
413  memcpy (eah->arp_sha, eh->ether_shost, 6);
414  memcpy (eah->arp_spa, ip_addr, 4);
415  }
416 
417  else if (eh->ether_type == 0x0008)
418  {
419  GET_HEADER (ip, struct iphdr, pck, offset);
420 
421  if (ip->protocol == 1)
422  {
423  ip->ihl = 5;
424  ip->version = 4;
425  ip->tos = 0;
426  ip->tot_len = 0x0000;
427  ip->id = 0;
428  ip->frag_off = 0;
429  ip->ttl = 0x40;
430  ip->protocol = 1;
431  ip->check = 0x0000;
432  ip->daddr = ip->saddr;
433  ((uint8_t *) & ip->saddr)[0] = ip_addr[0];
434  ((uint8_t *) & ip->saddr)[1] = ip_addr[1];
435  ((uint8_t *) & ip->saddr)[2] = ip_addr[2];
436  ((uint8_t *) & ip->saddr)[3] = ip_addr[3];
437 
438  GET_HEADER (icmp, struct icmphdr, pck, offset);
439 
440  icmp->type = 0x00;
441  icmp->code = 0;
442  icmp->checksum = cksum (icmp, sizeof (struct icmphdr));
443 
444  /* rest is payload */
445  offset = *size;
446 
447  ip->tot_len = __bswap_16 (offset - sizeof (struct ether_header));
448  ip->check = cksum (ip, sizeof (struct iphdr));
449  }
450  }
451 
452  assert (offset == *size && "unsupported protocol");
453  return 0;
454 }
455 
456 
457 int
458 resolve_packet3 (void **pck_, uint32_t * size, uint8_t ip_addr[4])
459 {
460  struct ether_header *eh;
461  struct ether_arp *eah;
462  struct iphdr *ip;
463  struct icmphdr *icmp;
464  int32_t offset = 0;
465  uint16_t encap_size = sizeof (struct ether_header);
466  void *pck = *pck_;
467 
468  if (pck == NULL)
469  return 0;
470 
471  *pck_ -= encap_size;
472  offset -= encap_size;
473 
474  GET_HEADER (eh, struct ether_header, pck, offset);
475 
476  uint8_t hw_daddr[6];
477  memset (hw_daddr, 0, sizeof (uint8_t) * 6);
478 
479  generate_eth (eh, hw_daddr);
480 
481  if (eh->ether_type == 0x0008)
482  {
483  GET_HEADER (ip, struct iphdr, pck, offset);
484 
485  if (ip->protocol == 1)
486  {
487  ip->ihl = 5;
488  ip->version = 4;
489  ip->tos = 0;
490  ip->tot_len = 0x0000;
491  ip->id = 0;
492  ip->frag_off = 0;
493  ip->ttl = 0x40;
494  ip->protocol = 1;
495  ip->check = 0x0000;
496  ip->daddr = ip->saddr;
497  ((uint8_t *) & ip->saddr)[0] = ip_addr[0];
498  ((uint8_t *) & ip->saddr)[1] = ip_addr[1];
499  ((uint8_t *) & ip->saddr)[2] = ip_addr[2];
500  ((uint8_t *) & ip->saddr)[3] = ip_addr[3];
501 
502  GET_HEADER (icmp, struct icmphdr, pck, offset);
503 
504  icmp->type = 0x00;
505  icmp->code = 0;
506  icmp->checksum = cksum (icmp, sizeof (struct icmphdr));
507 
508  /* rest is payload */
509  offset = *size;
510 
511  ip->tot_len = __bswap_16 (offset - sizeof (struct ether_header));
512  ip->check = cksum (ip, sizeof (struct iphdr));
513  }
514  }
515 
516  offset += encap_size;
517 
518  assert (offset != *size &&
519  "new packet length must be increased by encap size");
520 
521  /* overwrite packet size */
522  *size = offset;
523 
524  return 0;
525 }
static ssize_t generate_ip(struct iphdr *ip, uint8_t saddr[4], uint8_t daddr[4])
Definition: icmp_proto.c:275
Optimized string handling code, including c11-compliant "safe C library" variants.
#define NULL
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int resolve_packet2(void *pck, uint32_t *size, uint8_t ip_addr[4])
Definition: icmp_proto.c:381
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int generate_packet2(void *pck, uint32_t *size, uint8_t saddr[4], uint8_t daddr[4], uint8_t hw_daddr[6], uint32_t seq, icmpr_flow_mode_t mode)
Definition: icmp_proto.c:343
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Definition: icmp_proto.c:112
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Definition: icmp_proto.c:375
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Definition: icmp_proto.c:208
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Definition: icmp_proto.c:73
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Definition: icmp_proto.c:151
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Definition: icmp_proto.c:458
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Definition: icmp_proto.c:258
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Definition: icmp_proto.c:45
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Definition: icmp_proto.h:21
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Definition: icmp_proto.c:170