1/*
2 * Copyright (c) 2015 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15/*
16 * ip4/packet.h: ip4 packet format
17 *
18 * Copyright (c) 2008 Eliot Dresselhaus
19 *
20 * Permission is hereby granted, free of charge, to any person obtaining
21 * a copy of this software and associated documentation files (the
22 * "Software"), to deal in the Software without restriction, including
23 * without limitation the rights to use, copy, modify, merge, publish,
24 * distribute, sublicense, and/or sell copies of the Software, and to
25 * permit persons to whom the Software is furnished to do so, subject to
26 * the following conditions:
27 *
28 * The above copyright notice and this permission notice shall be
29 * included in all copies or substantial portions of the Software.
30 *
31 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
32 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
33 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
34 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
35 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
36 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
37 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
38 */
39
40#ifndef included_ip4_packet_h
41#define included_ip4_packet_h
42
43#include <vnet/ip/ip_packet.h>	/* for ip_csum_t */
44#include <vnet/tcp/tcp_packet.h>	/* for tcp_header_t */
45#include <vppinfra/byte_order.h>	/* for clib_net_to_host_u16 */
46
47/* IP4 address which can be accessed either as 4 bytes
48   or as a 32-bit number. */
49typedef union
50{
51  u8 data[4];
52  u32 data_u32;
53  /* Aliases. */
54  u8 as_u8[4];
55  u16 as_u16[2];
56  u32 as_u32;
57} ip4_address_t;
58
59typedef struct
60{
61  /* IP address must be first for ip_interface_address_get_address() to work */
62  ip4_address_t ip4_addr;
63  u32 fib_index;
64} ip4_address_fib_t;
65
66always_inline void
67ip4_addr_fib_init (ip4_address_fib_t * addr_fib,
68		   const ip4_address_t * address, u32 fib_index)
69{
70  clib_memcpy_fast (&addr_fib->ip4_addr, address,
71		    sizeof (addr_fib->ip4_addr));
72  addr_fib->fib_index = fib_index;
73}
74
75/* (src,dst) pair of addresses as found in packet header. */
76typedef struct
77{
78  ip4_address_t src, dst;
79} ip4_address_pair_t;
80
81typedef struct
82{
83  ip4_address_t addr, mask;
84} ip4_address_and_mask_t;
85
86/* If address is a valid netmask, return length of mask. */
87always_inline uword
88ip4_address_netmask_length (const ip4_address_t * a)
89{
90  uword result = 0;
91  uword i;
92  for (i = 0; i < ARRAY_LEN (a->as_u8); i++)
93    {
94      switch (a->as_u8[i])
95	{
96	case 0xff:
97	  result += 8;
98	  break;
99	case 0xfe:
100	  result += 7;
101	  goto done;
102	case 0xfc:
103	  result += 6;
104	  goto done;
105	case 0xf8:
106	  result += 5;
107	  goto done;
108	case 0xf0:
109	  result += 4;
110	  goto done;
111	case 0xe0:
112	  result += 3;
113	  goto done;
114	case 0xc0:
115	  result += 2;
116	  goto done;
117	case 0x80:
118	  result += 1;
119	  goto done;
120	case 0x00:
121	  result += 0;
122	  goto done;
123	default:
124	  /* Not a valid netmask mask. */
125	  return ~0;
126	}
127    }
128done:
129  return result;
130}
131
132typedef union
133{
134  struct
135  {
136    /* 4 bit packet length (in 32bit units) and version VVVVLLLL.
137       e.g. for packets w/ no options ip_version_and_header_length == 0x45. */
138    u8 ip_version_and_header_length;
139
140    /* Type of service. */
141    ip_dscp_t tos;
142
143    /* Total layer 3 packet length including this header. */
144    u16 length;
145
146    /* Fragmentation ID. */
147    u16 fragment_id;
148
149    /* 3 bits of flags and 13 bits of fragment offset (in units
150       of 8 byte quantities). */
151    u16 flags_and_fragment_offset;
152#define IP4_HEADER_FLAG_MORE_FRAGMENTS (1 << 13)
153#define IP4_HEADER_FLAG_DONT_FRAGMENT (1 << 14)
154#define IP4_HEADER_FLAG_CONGESTION (1 << 15)
155
156    /* Time to live decremented by router at each hop. */
157    u8 ttl;
158
159    /* Next level protocol packet. */
160    u8 protocol;
161
162    /* Checksum. */
163    u16 checksum;
164
165    /* Source and destination address. */
166    union
167    {
168      struct
169      {
170	ip4_address_t src_address, dst_address;
171      };
172      ip4_address_pair_t address_pair;
173    };
174  };
175
176  /* For checksumming we'll want to access IP header in word sized chunks. */
177  /* For 64 bit machines. */
178  /* *INDENT-OFF* */
179  CLIB_PACKED (struct {
180    u64 checksum_data_64[2];
181    u32 checksum_data_64_32[1];
182  });
183  /* *INDENT-ON* */
184
185  /* For 32 bit machines. */
186  /* *INDENT-OFF* */
187  CLIB_PACKED (struct {
188    u32 checksum_data_32[5];
189  });
190  /* *INDENT-ON* */
191} ip4_header_t;
192
193/* Value of ip_version_and_header_length for packets w/o options. */
194#define IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS \
195  ((4 << 4) | (sizeof (ip4_header_t) / sizeof (u32)))
196
197#define IP4_ROUTER_ALERT_OPTION 20
198
199always_inline u16
200ip4_get_fragment_offset (const ip4_header_t * i)
201{
202  return clib_net_to_host_u16 (i->flags_and_fragment_offset) & 0x1fff;
203}
204
205always_inline u16
206ip4_get_fragment_more (const ip4_header_t * i)
207{
208  return clib_net_to_host_u16 (i->flags_and_fragment_offset) &
209    IP4_HEADER_FLAG_MORE_FRAGMENTS;
210}
211
212always_inline int
213ip4_is_fragment (const ip4_header_t * i)
214{
215  return (i->flags_and_fragment_offset &
216	  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS));
217}
218
219always_inline int
220ip4_is_first_fragment (const ip4_header_t * i)
221{
222  return (i->flags_and_fragment_offset &
223	  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS)) ==
224    clib_net_to_host_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
225}
226
227/* Fragment offset in bytes. */
228always_inline int
229ip4_get_fragment_offset_bytes (const ip4_header_t * i)
230{
231  return 8 * ip4_get_fragment_offset (i);
232}
233
234always_inline int
235ip4_header_bytes (const ip4_header_t * i)
236{
237  return sizeof (u32) * (i->ip_version_and_header_length & 0xf);
238}
239
240always_inline void *
241ip4_next_header (ip4_header_t * i)
242{
243  return (void *) i + ip4_header_bytes (i);
244}
245
246always_inline u16
247ip4_header_checksum (ip4_header_t * i)
248{
249  u16 save, csum;
250  ip_csum_t sum;
251
252  save = i->checksum;
253  i->checksum = 0;
254  sum = ip_incremental_checksum (0, i, ip4_header_bytes (i));
255  csum = ~ip_csum_fold (sum);
256
257  i->checksum = save;
258
259  /* Make checksum agree for special case where either
260     0 or 0xffff would give same 1s complement sum. */
261  if (csum == 0 && save == 0xffff)
262    csum = save;
263
264  return csum;
265}
266
267always_inline void
268ip4_header_set_dscp (ip4_header_t * ip4, ip_dscp_t dscp)
269{
270  ip4->tos &= ~0xfc;
271  /* not masking the dscp value to save th instruction
272   * it shouldn't b necessary since the argument is an enum
273   * whose range is therefore constrained in the CP. in the
274   * DP it will have been taken from another packet, so again
275   * constrained in  value */
276  ip4->tos |= dscp << IP_PACKET_TC_FIELD_DSCP_BIT_SHIFT;
277}
278
279always_inline void
280ip4_header_set_ecn (ip4_header_t * ip4, ip_ecn_t ecn)
281{
282  ip4->tos &= ~IP_PACKET_TC_FIELD_ECN_MASK;
283  ip4->tos |= ecn;
284}
285
286always_inline void
287ip4_header_set_ecn_w_chksum (ip4_header_t * ip4, ip_ecn_t ecn)
288{
289  ip_csum_t sum = ip4->checksum;
290  u8 old = ip4->tos;
291  u8 new = (old & ~IP_PACKET_TC_FIELD_ECN_MASK) | ecn;
292
293  sum = ip_csum_update (sum, old, new, ip4_header_t, tos);
294  ip4->checksum = ip_csum_fold (sum);
295  ip4->tos = new;
296}
297
298always_inline ip_dscp_t
299ip4_header_get_dscp (const ip4_header_t * ip4)
300{
301  return (ip4->tos >> IP_PACKET_TC_FIELD_DSCP_BIT_SHIFT);
302}
303
304always_inline ip_ecn_t
305ip4_header_get_ecn (const ip4_header_t * ip4)
306{
307  return (ip4->tos & IP_PACKET_TC_FIELD_ECN_MASK);
308}
309
310always_inline void
311ip4_header_set_df (ip4_header_t * ip4)
312{
313  ip4->flags_and_fragment_offset |=
314    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
315}
316
317always_inline void
318ip4_header_clear_df (ip4_header_t * ip4)
319{
320  ip4->flags_and_fragment_offset &=
321    ~clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
322}
323
324always_inline u8
325ip4_header_get_df (const ip4_header_t * ip4)
326{
327  return (! !(ip4->flags_and_fragment_offset &
328	      clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT)));
329}
330
331static inline uword
332ip4_header_checksum_is_valid (ip4_header_t * i)
333{
334  return i->checksum == ip4_header_checksum (i);
335}
336
337#define ip4_partial_header_checksum_x1(ip0,sum0)			\
338do {									\
339  if (BITS (ip_csum_t) > 32)						\
340    {									\
341      sum0 = ip0->checksum_data_64[0];					\
342      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]);	\
343      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]);	\
344    }									\
345  else									\
346    {									\
347      sum0 = ip0->checksum_data_32[0];					\
348      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]);	\
349      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]);	\
350      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]);	\
351      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]);	\
352    }									\
353} while (0)
354
355#define ip4_partial_header_checksum_x2(ip0,ip1,sum0,sum1)		\
356do {									\
357  if (BITS (ip_csum_t) > 32)						\
358    {									\
359      sum0 = ip0->checksum_data_64[0];					\
360      sum1 = ip1->checksum_data_64[0];					\
361      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]);	\
362      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64[1]);	\
363      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]);	\
364      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64_32[0]);	\
365    }									\
366  else									\
367    {									\
368      sum0 = ip0->checksum_data_32[0];					\
369      sum1 = ip1->checksum_data_32[0];					\
370      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]);	\
371      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[1]);	\
372      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]);	\
373      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[2]);	\
374      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]);	\
375      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[3]);	\
376      sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]);	\
377      sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[4]);	\
378    }									\
379} while (0)
380
381always_inline uword
382ip4_address_is_multicast (const ip4_address_t * a)
383{
384  return (a->data[0] & 0xf0) == 0xe0;
385}
386
387always_inline uword
388ip4_address_is_global_broadcast (const ip4_address_t * a)
389{
390  return (a->as_u32) == 0xffffffff;
391}
392
393always_inline void
394ip4_multicast_address_set_for_group (ip4_address_t * a,
395				     ip_multicast_group_t g)
396{
397  ASSERT ((u32) g < (1 << 28));
398  a->as_u32 = clib_host_to_net_u32 ((0xe << 28) + g);
399}
400
401always_inline void
402ip4_multicast_ethernet_address (u8 * ethernet_address,
403				const ip4_address_t * a)
404{
405  const u8 *d = a->as_u8;
406
407  ethernet_address[0] = 0x01;
408  ethernet_address[1] = 0x00;
409  ethernet_address[2] = 0x5e;
410  ethernet_address[3] = d[1] & 0x7f;
411  ethernet_address[4] = d[2];
412  ethernet_address[5] = d[3];
413}
414
415always_inline void
416ip4_tcp_reply_x1 (ip4_header_t * ip0, tcp_header_t * tcp0)
417{
418  u32 src0, dst0;
419
420  src0 = ip0->src_address.data_u32;
421  dst0 = ip0->dst_address.data_u32;
422  ip0->src_address.data_u32 = dst0;
423  ip0->dst_address.data_u32 = src0;
424
425  src0 = tcp0->src;
426  dst0 = tcp0->dst;
427  tcp0->src = dst0;
428  tcp0->dst = src0;
429}
430
431always_inline void
432ip4_tcp_reply_x2 (ip4_header_t * ip0, ip4_header_t * ip1,
433		  tcp_header_t * tcp0, tcp_header_t * tcp1)
434{
435  u32 src0, dst0, src1, dst1;
436
437  src0 = ip0->src_address.data_u32;
438  src1 = ip1->src_address.data_u32;
439  dst0 = ip0->dst_address.data_u32;
440  dst1 = ip1->dst_address.data_u32;
441  ip0->src_address.data_u32 = dst0;
442  ip1->src_address.data_u32 = dst1;
443  ip0->dst_address.data_u32 = src0;
444  ip1->dst_address.data_u32 = src1;
445
446  src0 = tcp0->src;
447  src1 = tcp1->src;
448  dst0 = tcp0->dst;
449  dst1 = tcp1->dst;
450  tcp0->src = dst0;
451  tcp1->src = dst1;
452  tcp0->dst = src0;
453  tcp1->dst = src1;
454}
455
456#endif /* included_ip4_packet_h */
457
458/*
459 * fd.io coding-style-patch-verification: ON
460 *
461 * Local Variables:
462 * eval: (c-set-style "gnu")
463 * End:
464 */
465