summaryrefslogtreecommitdiffstats
path: root/src/vnet/ip/ip4_packet.h
blob: fee0c8cbcd774cf44abcea84ff3053adf01a3a3d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * ip4/packet.h: ip4 packet format
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef included_ip4_packet_h
#define included_ip4_packet_h

#include <vnet/ip/ip_packet.h>	/* for ip_csum_t */
#include <vnet/tcp/tcp_packet.h>	/* for tcp_header_t */
#include <vppinfra/byte_order.h>	/* for clib_net_to_host_u16 */

/* IP4 address which can be accessed either as 4 bytes
   or as a 32-bit number. */
typedef union
{
  u8 data[4];
  u32 data_u32;
  /* Aliases. */
  u8 as_u8[4];
  u16 as_u16[2];
  u32 as_u32;
} ip4_address_t;

typedef struct
{
  /* IP address must be first for ip_interface_address_get_address() to work */
  ip4_address_t ip4_addr;
  u32 fib_index;
} ip4_address_fib_t;

always_inline void
ip4_addr_fib_init (ip4_address_fib_t * addr_fib,
		   const ip4_address_t * address, u32 fib_index)
{
  clib_memcpy_fast (&addr_fib->ip4_addr, address,
		    sizeof (addr_fib->ip4_addr));
  addr_fib->fib_index = fib_index;
}

/* (src,dst) pair of addresses as found in packet header. */
typedef struct
{
  ip4_address_t src, dst;
} ip4_address_pair_t;

typedef struct
{
  ip4_address_t addr, mask;
} ip4_address_and_mask_t;

typedef union
{
  struct
  {
    /* 4 bit packet length (in 32bit units) and version VVVVLLLL.
       e.g. for packets w/ no options ip_version_and_header_length == 0x45. */
    u8 ip_version_and_header_length;

    /* Type of service. */
    ip_dscp_t tos;

    /* Total layer 3 packet length including this header. */
    u16 length;

    /* Fragmentation ID. */
    u16 fragment_id;

    /* 3 bits of flags and 13 bits of fragment offset (in units
       of 8 byte quantities). */
    u16 flags_and_fragment_offset;
#define IP4_HEADER_FLAG_MORE_FRAGMENTS (1 << 13)
#define IP4_HEADER_FLAG_DONT_FRAGMENT (1 << 14)
#define IP4_HEADER_FLAG_CONGESTION (1 << 15)

    /* Time to live decremented by router at each hop. */
    u8 ttl;

    /* Next level protocol packet. */
    u8 protocol;

    /* Checksum. */
    u16 checksum;

    /* Source and destination address. */
    union
    {
      struct
      {
	ip4_address_t src_address, dst_address;
      };
      ip4_address_pair_t address_pair;
    };
  };

  /* For checksumming we'll want to access IP header in word sized chunks. */
  /* For 64 bit machines. */
  /* *INDENT-OFF* */
  CLIB_PACKED (struct {
    u64 checksum_data_64[2];
    u32 checksum_data_64_32[1];
  });
  /* *INDENT-ON* */

  /* For 32 bit machines. */
  /* *INDENT-OFF* */
  CLIB_PACKED (struct {
    u32 checksum_data_32[5];
  });
  /* *INDENT-ON* */
} ip4_header_t;

/* Value of ip_version_and_header_length for packets w/o options. */
#define IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS \
  ((4 << 4) | (sizeof (ip4_header_t) / sizeof (u32)))

#define IP4_ROUTER_ALERT_OPTION 20

always_inline u16
ip4_get_fragment_offset (const ip4_header_t * i)
{
  return clib_net_to_host_u16 (i->flags_and_fragment_offset) & 0x1fff;
}

always_inline u16
ip4_get_fragment_more (const ip4_header_t * i)
{
  return clib_net_to_host_u16 (i->flags_and_fragment_offset) &
    IP4_HEADER_FLAG_MORE_FRAGMENTS;
}

always_inline int
ip4_is_fragment (const ip4_header_t * i)
{
  return (i->flags_and_fragment_offset &
	  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS));
}

always_inline int
ip4_is_first_fragment (const ip4_header_t * i)
{
  return (i->flags_and_fragment_offset &
	  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS)) ==
    clib_net_to_host_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
}

/* Fragment offset in bytes. */
always_inline int
ip4_get_fragment_offset_bytes (const ip4_header_t * i)
{
  return 8 * ip4_get_fragment_offset (i);
}

always_inline int
ip4_header_bytes (const ip4_header_t * i)
{
  return sizeof (u32) * (i->ip_version_and_header_length & 0xf);
}

always_inline void *
ip4_next_header (ip4_header_t * i)
{
  return (void *) i + ip4_header_bytes (i);
}

always_inline u16
ip4_header_checksum (ip4_header_t * i)
{
  int option_len = (i->ip_version_and_header_length & 0xf) - 5;
  uword sum = 0;
#if uword_bits == 64
  u32 *iphdr = (u32 *) i;

  sum += iphdr[0];
  sum += iphdr[1];
  sum += *(u16 *) (iphdr + 2);
  /* skip checksum */
  sum += iphdr[3];
  sum += iphdr[4];

  if (PREDICT_FALSE (option_len > 0))
    switch (option_len)
      {
      case 10:
	sum += iphdr[14];
      case 9:
	sum += iphdr[13];
      case 8:
	sum += iphdr[12];
      case 7:
	sum += iphdr[11];
      case 6:
	sum += iphdr[10];
      case 5:
	sum += iphdr[9];
      case 4:
	sum += iphdr[8];
      case 3:
	sum += iphdr[7];
      case 2:
	sum += iphdr[6];
      case 1:
	sum += iphdr[5];
      default:
	break;
      }

  sum = ((u32) sum) + (sum >> 32);
#else
  u16 *iphdr = (u16 *) i;

  sum += iphdr[0];
  sum += iphdr[1];
  sum += iphdr[2];
  sum += iphdr[3];
  sum += iphdr[4];
  /* skip checksum */
  sum += iphdr[6];
  sum += iphdr[7];
  sum += iphdr[8];
  sum += iphdr[9];

  if (PREDICT_FALSE (option_len > 0))
    switch (option_len)
      {
      case 10:
	sum += iphdr[28];
	sum += iphdr[29];
      case 9:
	sum += iphdr[26];
	sum += iphdr[27];
      case 8:
	sum += iphdr[24];
	sum += iphdr[25];
      case 7:
	sum += iphdr[22];
	sum += iphdr[23];
      case 6:
	sum += iphdr[20];
	sum += iphdr[21];
      case 5:
	sum += iphdr[18];
	sum += iphdr[19];
      case 4:
	sum += iphdr[16];
	sum += iphdr[17];
      case 3:
	sum += iphdr[14];
	sum += iphdr[15];
      case 2:
	sum += iphdr[12];
	sum += iphdr[13];
      case 1:
	sum += iphdr[10];
	sum += iphdr[11];
      default:
	break;
      }
#endif

  sum = ((u16) sum) + (sum >> 16);
  sum = ((u16) sum) + (sum >> 16);
  return ~((u16) sum);
}

always_inline void
ip4_header_set_dscp (ip4_header_t * ip4, ip_dscp_t dscp)
{
  ip4->tos &= ~0xfc;
  /* not masking the dscp value to save th instruction
   * it shouldn't b necessary since the argument is an enum
   * whose range is therefore constrained in the CP. in the
   * DP it will have been taken from another packet, so again
   * constrained in  value */
  ip4->tos |= dscp << IP_PACKET_TC_FIELD_DSCP_BIT_SHIFT;
}

always_inline void
ip4_header_set_ecn (ip4_header_t * ip4, ip_ecn_t ecn)
{
  ip4->tos &= ~IP_PACKET_TC_FIELD_ECN_MASK;
  ip4->tos |= ecn;
}

always_inline void
ip4_header_set_ecn_w_chksum (ip4_header_t * ip4, ip_ecn_t ecn)
{
  ip_csum_t sum = ip4->checksum;
  u8 old = ip4->tos;
  u8 new = (old & ~IP_PACKET_TC_FIELD_ECN_MASK) | ecn;

  sum = ip_csum_update (sum, old, new, ip4_header_t, tos);
  ip4->checksum = ip_csum_fold (sum);
  ip4->tos = new;
}

always_inline ip_dscp_t
ip4_header_get_dscp (const ip4_header_t * ip4)
{
  return (ip4->tos >> IP_PACKET_TC_FIELD_DSCP_BIT_SHIFT);
}

always_inline ip_ecn_t
ip4_header_get_ecn (const ip4_header_t * ip4)
{
  return (ip4->tos & IP_PACKET_TC_FIELD_ECN_MASK);
}

always_inline void
ip4_header_set_df (ip4_header_t * ip4)
{
  ip4->flags_and_fragment_offset |=
    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
}

always_inline void
ip4_header_clear_df (ip4_header_t * ip4)
{
  ip4->flags_and_fragment_offset &=
    ~clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
}

always_inline u8
ip4_header_get_df (const ip4_header_t * ip4)
{
  return (! !(ip4->flags_and_fragment_offset &
	      clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT)));
}

static inline uword
ip4_header_checksum_is_valid (ip4_header_t * i)
{
  return i->checksum == ip4_header_checksum (i);
}

#define ip4_partial_header_checksum_x1(ip0,sum0)			\
do {									\
  if (BITS (ip_csum_t) > 32)						\
    {									\
      sum0 = ip0->checksum_data_64[0];					\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]);	\
    }									\
  else									\
    {									\
      sum0 = ip0->checksum_data_32[0];					\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]);	\
    }									\
} while (0)

#define ip4_partial_header_checksum_x2(ip0,ip1,sum0,sum1)		\
do {									\
  if (BITS (ip_csum_t) > 32)						\
    {									\
      sum0 = ip0->checksum_data_64[0];					\
      sum1 = ip1->checksum_data_64[0];					\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]);	\
      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64[1]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]);	\
      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64_32[0]);	\
    }									\
  else									\
    {									\
      sum0 = ip0->checksum_data_32[0];					\
      sum1 = ip1->checksum_data_32[0];					\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]);	\
      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[1]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]);	\
      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[2]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]);	\
      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[3]);	\
      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]);	\
      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[4]);	\
    }									\
} while (0)

always_inline uword
ip4_address_is_multicast (const ip4_address_t * a)
{
  return (a->data[0] & 0xf0) == 0xe0;
}

always_inline uword
ip4_address_is_global_broadcast (const ip4_address_t * a)
{
  return (a->as_u32) == 0xffffffff;
}

always_inline void
ip4_multicast_address_set_for_group (ip4_address_t * a,
				     ip_multicast_group_t g)
{
  ASSERT ((u32) g < (1 << 28));
  a->as_u32 = clib_host_to_net_u32 ((0xe << 28) + g);
}

always_inline void
ip4_multicast_ethernet_address (u8 * ethernet_address,
				const ip4_address_t * a)
{
  const u8 *d = a->as_u8;

  ethernet_address[0] = 0x01;
  ethernet_address[1] = 0x00;
  ethernet_address[2] = 0x5e;
  ethernet_address[3] = d[1] & 0x7f;
  ethernet_address[4] = d[2];
  ethernet_address[5] = d[3];
}

always_inline void
ip4_tcp_reply_x1 (ip4_header_t * ip0, tcp_header_t * tcp0)
{
  u32 src0, dst0;

  src0 = ip0->src_address.data_u32;
  dst0 = ip0->dst_address.data_u32;
  ip0->src_address.data_u32 = dst0;
  ip0->dst_address.data_u32 = src0;

  src0 = tcp0->src;
  dst0 = tcp0->dst;
  tcp0->src = dst0;
  tcp0->dst = src0;
}

always_inline void
ip4_tcp_reply_x2 (ip4_header_t * ip0, ip4_header_t * ip1,
		  tcp_header_t * tcp0, tcp_header_t * tcp1)
{
  u32 src0, dst0, src1, dst1;

  src0 = ip0->src_address.data_u32;
  src1 = ip1->src_address.data_u32;
  dst0 = ip0->dst_address.data_u32;
  dst1 = ip1->dst_address.data_u32;
  ip0->src_address.data_u32 = dst0;
  ip1->src_address.data_u32 = dst1;
  ip0->dst_address.data_u32 = src0;
  ip1->dst_address.data_u32 = src1;

  src0 = tcp0->src;
  src1 = tcp1->src;
  dst0 = tcp0->dst;
  dst1 = tcp1->dst;
  tcp0->src = dst0;
  tcp1->src = dst1;
  tcp0->dst = src0;
  tcp1->dst = src1;
}

#endif /* included_ip4_packet_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */