FD.io VPP  v18.04-17-g3a0d853
Vector Packet Processing
ip4_packet.h
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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. */
49 typedef union
50 {
51  u8 data[4];
53  /* Aliases. */
54  u8 as_u8[4];
55  u16 as_u16[2];
58 
59 typedef struct
60 {
61  /* IP address must be first for ip_interface_address_get_address() to work */
65 
66 always_inline void
68  u32 fib_index)
69 {
70  clib_memcpy (&addr_fib->ip4_addr, address, sizeof (addr_fib->ip4_addr));
71  addr_fib->fib_index = fib_index;
72 }
73 
74 /* (src,dst) pair of addresses as found in packet header. */
75 typedef struct
76 {
79 
80 /* If address is a valid netmask, return length of mask. */
83 {
84  uword result = 0;
85  uword i;
86  for (i = 0; i < ARRAY_LEN (a->as_u8); i++)
87  {
88  switch (a->as_u8[i])
89  {
90  case 0xff:
91  result += 8;
92  break;
93  case 0xfe:
94  result += 7;
95  goto done;
96  case 0xfc:
97  result += 6;
98  goto done;
99  case 0xf8:
100  result += 5;
101  goto done;
102  case 0xf0:
103  result += 4;
104  goto done;
105  case 0xe0:
106  result += 3;
107  goto done;
108  case 0xc0:
109  result += 2;
110  goto done;
111  case 0x80:
112  result += 1;
113  goto done;
114  case 0x00:
115  result += 0;
116  goto done;
117  default:
118  /* Not a valid netmask mask. */
119  return ~0;
120  }
121  }
122 done:
123  return result;
124 }
125 
126 typedef union
127 {
128  struct
129  {
130  /* 4 bit packet length (in 32bit units) and version VVVVLLLL.
131  e.g. for packets w/ no options ip_version_and_header_length == 0x45. */
133 
134  /* Type of service. */
136 
137  /* Total layer 3 packet length including this header. */
139 
140  /* Fragmentation ID. */
142 
143  /* 3 bits of flags and 13 bits of fragment offset (in units
144  of 8 byte quantities). */
146 #define IP4_HEADER_FLAG_MORE_FRAGMENTS (1 << 13)
147 #define IP4_HEADER_FLAG_DONT_FRAGMENT (1 << 14)
148 #define IP4_HEADER_FLAG_CONGESTION (1 << 15)
149 
150  /* Time to live decremented by router at each hop. */
152 
153  /* Next level protocol packet. */
155 
156  /* Checksum. */
158 
159  /* Source and destination address. */
160  union
161  {
162  struct
163  {
165  };
167  };
168  };
169 
170  /* For checksumming we'll want to access IP header in word sized chunks. */
171  /* For 64 bit machines. */
172  /* *INDENT-OFF* */
173  CLIB_PACKED (struct {
174  u64 checksum_data_64[2];
175  u32 checksum_data_64_32[1];
176  });
177  /* *INDENT-ON* */
178 
179  /* For 32 bit machines. */
180  /* *INDENT-OFF* */
181  CLIB_PACKED (struct {
182  u32 checksum_data_32[5];
183  });
184  /* *INDENT-ON* */
185 } ip4_header_t;
186 
187 /* Value of ip_version_and_header_length for packets w/o options. */
188 #define IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS \
189  ((4 << 4) | (sizeof (ip4_header_t) / sizeof (u32)))
190 
191 always_inline int
192 ip4_get_fragment_offset (ip4_header_t * i)
193 {
194  return clib_net_to_host_u16 (i->flags_and_fragment_offset) & 0x1fff;
195 }
196 
197 always_inline int
198 ip4_get_fragment_more (ip4_header_t * i)
199 {
200  return clib_net_to_host_u16 (i->flags_and_fragment_offset) &
202 }
203 
204 always_inline int
205 ip4_is_fragment (ip4_header_t * i)
206 {
207  return (i->flags_and_fragment_offset &
208  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS));
209 }
210 
211 always_inline int
212 ip4_is_first_fragment (ip4_header_t * i)
213 {
214  return (i->flags_and_fragment_offset &
215  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS)) ==
216  clib_net_to_host_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
217 }
218 
219 /* Fragment offset in bytes. */
220 always_inline int
222 {
223  return 8 * ip4_get_fragment_offset (i);
224 }
225 
226 always_inline int
227 ip4_header_bytes (ip4_header_t * i)
228 {
229  return sizeof (u32) * (i->ip_version_and_header_length & 0xf);
230 }
231 
232 always_inline void *
233 ip4_next_header (ip4_header_t * i)
234 {
235  return (void *) i + ip4_header_bytes (i);
236 }
237 
239 ip4_header_checksum (ip4_header_t * i)
240 {
241  u16 save, csum;
242  ip_csum_t sum;
243 
244  save = i->checksum;
245  i->checksum = 0;
246  sum = ip_incremental_checksum (0, i, ip4_header_bytes (i));
247  csum = ~ip_csum_fold (sum);
248 
249  i->checksum = save;
250 
251  /* Make checksum agree for special case where either
252  0 or 0xffff would give same 1s complement sum. */
253  if (csum == 0 && save == 0xffff)
254  csum = save;
255 
256  return csum;
257 }
258 
259 static inline uword
261 {
262  return i->checksum == ip4_header_checksum (i);
263 }
264 
265 #define ip4_partial_header_checksum_x1(ip0,sum0) \
266 do { \
267  if (BITS (ip_csum_t) > 32) \
268  { \
269  sum0 = ip0->checksum_data_64[0]; \
270  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]); \
271  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]); \
272  } \
273  else \
274  { \
275  sum0 = ip0->checksum_data_32[0]; \
276  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]); \
277  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]); \
278  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]); \
279  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]); \
280  } \
281 } while (0)
282 
283 #define ip4_partial_header_checksum_x2(ip0,ip1,sum0,sum1) \
284 do { \
285  if (BITS (ip_csum_t) > 32) \
286  { \
287  sum0 = ip0->checksum_data_64[0]; \
288  sum1 = ip1->checksum_data_64[0]; \
289  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]); \
290  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64[1]); \
291  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]); \
292  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64_32[0]); \
293  } \
294  else \
295  { \
296  sum0 = ip0->checksum_data_32[0]; \
297  sum1 = ip1->checksum_data_32[0]; \
298  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]); \
299  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[1]); \
300  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]); \
301  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[2]); \
302  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]); \
303  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[3]); \
304  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]); \
305  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[4]); \
306  } \
307 } while (0)
308 
311 {
312  return (a->data[0] & 0xf0) == 0xe0;
313 }
314 
315 always_inline void
318 {
319  ASSERT ((u32) g < (1 << 28));
320  a->as_u32 = clib_host_to_net_u32 ((0xe << 28) + g);
321 }
322 
323 always_inline void
325 {
326  u8 *d = a->as_u8;
327 
328  ethernet_address[0] = 0x01;
329  ethernet_address[1] = 0x00;
330  ethernet_address[2] = 0x5e;
331  ethernet_address[3] = d[1] & 0x7f;
332  ethernet_address[4] = d[2];
333  ethernet_address[5] = d[3];
334 }
335 
336 always_inline void
337 ip4_tcp_reply_x1 (ip4_header_t * ip0, tcp_header_t * tcp0)
338 {
339  u32 src0, dst0;
340 
341  src0 = ip0->src_address.data_u32;
342  dst0 = ip0->dst_address.data_u32;
343  ip0->src_address.data_u32 = dst0;
344  ip0->dst_address.data_u32 = src0;
345 
346  src0 = tcp0->src;
347  dst0 = tcp0->dst;
348  tcp0->src = dst0;
349  tcp0->dst = src0;
350 }
351 
352 always_inline void
353 ip4_tcp_reply_x2 (ip4_header_t * ip0, ip4_header_t * ip1,
354  tcp_header_t * tcp0, tcp_header_t * tcp1)
355 {
356  u32 src0, dst0, src1, dst1;
357 
358  src0 = ip0->src_address.data_u32;
359  src1 = ip1->src_address.data_u32;
360  dst0 = ip0->dst_address.data_u32;
361  dst1 = ip1->dst_address.data_u32;
362  ip0->src_address.data_u32 = dst0;
363  ip1->src_address.data_u32 = dst1;
364  ip0->dst_address.data_u32 = src0;
365  ip1->dst_address.data_u32 = src1;
366 
367  src0 = tcp0->src;
368  src1 = tcp1->src;
369  dst0 = tcp0->dst;
370  dst1 = tcp1->dst;
371  tcp0->src = dst0;
372  tcp1->src = dst1;
373  tcp0->dst = src0;
374  tcp1->dst = src1;
375 }
376 
377 #endif /* included_ip4_packet_h */
378 
379 /*
380  * fd.io coding-style-patch-verification: ON
381  *
382  * Local Variables:
383  * eval: (c-set-style "gnu")
384  * End:
385  */
ip4_address_t ip4_addr
Definition: ip4_packet.h:62
a
Definition: bitmap.h:516
ip4_address_t src_address
Definition: ip4_packet.h:164
static int ip4_header_bytes(ip4_header_t *i)
Definition: ip4_packet.h:227
int i
uword ip_csum_t
Definition: ip_packet.h:90
u16 flags_and_fragment_offset
Definition: ip4_packet.h:145
struct _tcp_header tcp_header_t
static void ip4_tcp_reply_x1(ip4_header_t *ip0, tcp_header_t *tcp0)
Definition: ip4_packet.h:337
static uword ip4_header_checksum_is_valid(ip4_header_t *i)
Definition: ip4_packet.h:260
ip_csum_t ip_incremental_checksum(ip_csum_t sum, void *_data, uword n_bytes)
Definition: ip_checksum.c:43
#define always_inline
Definition: clib.h:92
static uword ip4_address_netmask_length(ip4_address_t *a)
Definition: ip4_packet.h:82
ip4_address_t dst_address
Definition: ip4_packet.h:164
static int ip4_get_fragment_offset(ip4_header_t *i)
Definition: ip4_packet.h:192
unsigned long u64
Definition: types.h:89
static void * ip4_next_header(ip4_header_t *i)
Definition: ip4_packet.h:233
static int ip4_is_fragment(ip4_header_t *i)
Definition: ip4_packet.h:205
ip4_address_pair_t address_pair
Definition: ip4_packet.h:166
static uword ip4_address_is_multicast(ip4_address_t *a)
Definition: ip4_packet.h:310
static void ip4_tcp_reply_x2(ip4_header_t *ip0, ip4_header_t *ip1, tcp_header_t *tcp0, tcp_header_t *tcp1)
Definition: ip4_packet.h:353
#define IP4_HEADER_FLAG_MORE_FRAGMENTS
Definition: ip4_packet.h:146
static void ip4_multicast_ethernet_address(u8 *ethernet_address, ip4_address_t *a)
Definition: ip4_packet.h:324
ip4_address_t src
Definition: ip4_packet.h:77
#define clib_memcpy(a, b, c)
Definition: string.h:75
static int ip4_is_first_fragment(ip4_header_t *i)
Definition: ip4_packet.h:212
#define ARRAY_LEN(x)
Definition: clib.h:59
static void ip4_addr_fib_init(ip4_address_fib_t *addr_fib, ip4_address_t *address, u32 fib_index)
Definition: ip4_packet.h:67
#define ASSERT(truth)
unsigned int u32
Definition: types.h:88
static void ip4_multicast_address_set_for_group(ip4_address_t *a, ip_multicast_group_t g)
Definition: ip4_packet.h:316
static int ip4_get_fragment_more(ip4_header_t *i)
Definition: ip4_packet.h:198
u64 uword
Definition: types.h:112
static int ip4_get_fragment_offset_bytes(ip4_header_t *i)
Definition: ip4_packet.h:221
unsigned short u16
Definition: types.h:57
unsigned char u8
Definition: types.h:56
ip_multicast_group_t
Definition: ip_packet.h:80
u8 ip_version_and_header_length
Definition: ip4_packet.h:132
static u16 ip4_header_checksum(ip4_header_t *i)
Definition: ip4_packet.h:239
static u16 ip_csum_fold(ip_csum_t c)
Definition: ip_packet.h:145
#define CLIB_PACKED(x)
Definition: clib.h:78