FD.io VPP  v17.01-9-ge7dcee4
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/ip/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];
57 
58 typedef struct
59 {
60  /* IP address must be first for ip_interface_address_get_address() to work */
64 
65 always_inline void
67  u32 fib_index)
68 {
69  clib_memcpy (&addr_fib->ip4_addr, address, sizeof (addr_fib->ip4_addr));
70  addr_fib->fib_index = fib_index;
71 }
72 
73 /* (src,dst) pair of addresses as found in packet header. */
74 typedef struct
75 {
78 
79 /* If address is a valid netmask, return length of mask. */
82 {
83  uword result = 0;
84  uword i;
85  for (i = 0; i < ARRAY_LEN (a->as_u8); i++)
86  {
87  switch (a->as_u8[i])
88  {
89  case 0xff:
90  result += 8;
91  break;
92  case 0xfe:
93  result += 7;
94  goto done;
95  case 0xfc:
96  result += 6;
97  goto done;
98  case 0xf8:
99  result += 5;
100  goto done;
101  case 0xf0:
102  result += 4;
103  goto done;
104  case 0xe0:
105  result += 3;
106  goto done;
107  case 0xc0:
108  result += 2;
109  goto done;
110  case 0x80:
111  result += 1;
112  goto done;
113  case 0x00:
114  result += 0;
115  goto done;
116  default:
117  /* Not a valid netmask mask. */
118  return ~0;
119  }
120  }
121 done:
122  return result;
123 }
124 
125 typedef union
126 {
127  struct
128  {
129  /* 4 bit packet length (in 32bit units) and version VVVVLLLL.
130  e.g. for packets w/ no options ip_version_and_header_length == 0x45. */
132 
133  /* Type of service. */
135 
136  /* Total layer 3 packet length including this header. */
138 
139  /* Fragmentation ID. */
141 
142  /* 3 bits of flags and 13 bits of fragment offset (in units
143  of 8 byte quantities). */
145 #define IP4_HEADER_FLAG_MORE_FRAGMENTS (1 << 13)
146 #define IP4_HEADER_FLAG_DONT_FRAGMENT (1 << 14)
147 #define IP4_HEADER_FLAG_CONGESTION (1 << 15)
148 
149  /* Time to live decremented by router at each hop. */
151 
152  /* Next level protocol packet. */
154 
155  /* Checksum. */
157 
158  /* Source and destination address. */
159  union
160  {
161  struct
162  {
164  };
166  };
167  };
168 
169  /* For checksumming we'll want to access IP header in word sized chunks. */
170  /* For 64 bit machines. */
171  /* *INDENT-OFF* */
172  CLIB_PACKED (struct {
173  u64 checksum_data_64[2];
174  u32 checksum_data_64_32[1];
175  });
176  /* *INDENT-ON* */
177 
178  /* For 32 bit machines. */
179  /* *INDENT-OFF* */
180  CLIB_PACKED (struct {
181  u32 checksum_data_32[5];
182  });
183  /* *INDENT-ON* */
184 } ip4_header_t;
185 
186 /* Value of ip_version_and_header_length for packets w/o options. */
187 #define IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS \
188  ((4 << 4) | (sizeof (ip4_header_t) / sizeof (u32)))
189 
190 always_inline int
191 ip4_get_fragment_offset (ip4_header_t * i)
192 {
193  return clib_net_to_host_u16 (i->flags_and_fragment_offset) & 0x1fff;
194 }
195 
196 always_inline int
197 ip4_get_fragment_more (ip4_header_t * i)
198 {
199  return clib_net_to_host_u16 (i->flags_and_fragment_offset) &
201 }
202 
203 always_inline int
204 ip4_is_fragment (ip4_header_t * i)
205 {
206  return (i->flags_and_fragment_offset &
207  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS));
208 }
209 
210 always_inline int
211 ip4_is_first_fragment (ip4_header_t * i)
212 {
213  return (i->flags_and_fragment_offset &
214  clib_net_to_host_u16 (0x1fff | IP4_HEADER_FLAG_MORE_FRAGMENTS)) ==
215  clib_net_to_host_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
216 }
217 
218 /* Fragment offset in bytes. */
219 always_inline int
221 {
222  return 8 * ip4_get_fragment_offset (i);
223 }
224 
225 always_inline int
226 ip4_header_bytes (ip4_header_t * i)
227 {
228  return sizeof (u32) * (i->ip_version_and_header_length & 0xf);
229 }
230 
231 always_inline void *
232 ip4_next_header (ip4_header_t * i)
233 {
234  return (void *) i + ip4_header_bytes (i);
235 }
236 
238 ip4_header_checksum (ip4_header_t * i)
239 {
240  u16 save, csum;
241  ip_csum_t sum;
242 
243  save = i->checksum;
244  i->checksum = 0;
245  sum = ip_incremental_checksum (0, i, ip4_header_bytes (i));
246  csum = ~ip_csum_fold (sum);
247 
248  i->checksum = save;
249 
250  /* Make checksum agree for special case where either
251  0 or 0xffff would give same 1s complement sum. */
252  if (csum == 0 && save == 0xffff)
253  csum = save;
254 
255  return csum;
256 }
257 
258 static inline uword
260 {
261  return i->checksum == ip4_header_checksum (i);
262 }
263 
264 #define ip4_partial_header_checksum_x1(ip0,sum0) \
265 do { \
266  if (BITS (ip_csum_t) > 32) \
267  { \
268  sum0 = ip0->checksum_data_64[0]; \
269  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]); \
270  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]); \
271  } \
272  else \
273  { \
274  sum0 = ip0->checksum_data_32[0]; \
275  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]); \
276  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]); \
277  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]); \
278  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]); \
279  } \
280 } while (0)
281 
282 #define ip4_partial_header_checksum_x2(ip0,ip1,sum0,sum1) \
283 do { \
284  if (BITS (ip_csum_t) > 32) \
285  { \
286  sum0 = ip0->checksum_data_64[0]; \
287  sum1 = ip1->checksum_data_64[0]; \
288  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64[1]); \
289  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64[1]); \
290  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_64_32[0]); \
291  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_64_32[0]); \
292  } \
293  else \
294  { \
295  sum0 = ip0->checksum_data_32[0]; \
296  sum1 = ip1->checksum_data_32[0]; \
297  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[1]); \
298  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[1]); \
299  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[2]); \
300  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[2]); \
301  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[3]); \
302  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[3]); \
303  sum0 = ip_csum_with_carry (sum0, ip0->checksum_data_32[4]); \
304  sum1 = ip_csum_with_carry (sum1, ip1->checksum_data_32[4]); \
305  } \
306 } while (0)
307 
310 {
311  return (a->data[0] & 0xf0) == 0xe0;
312 }
313 
314 always_inline void
317 {
318  ASSERT ((u32) g < (1 << 28));
319  a->as_u32 = clib_host_to_net_u32 ((0xe << 28) + g);
320 }
321 
322 always_inline void
324 {
325  u8 *d = a->as_u8;
326 
327  ethernet_address[0] = 0x01;
328  ethernet_address[1] = 0x00;
329  ethernet_address[2] = 0x5e;
330  ethernet_address[3] = d[1] & 0x7f;
331  ethernet_address[4] = d[2];
332  ethernet_address[5] = d[3];
333 }
334 
335 always_inline void
336 ip4_tcp_reply_x1 (ip4_header_t * ip0, tcp_header_t * tcp0)
337 {
338  u32 src0, dst0;
339 
340  src0 = ip0->src_address.data_u32;
341  dst0 = ip0->dst_address.data_u32;
342  ip0->src_address.data_u32 = dst0;
343  ip0->dst_address.data_u32 = src0;
344 
345  src0 = tcp0->ports.src;
346  dst0 = tcp0->ports.dst;
347  tcp0->ports.src = dst0;
348  tcp0->ports.dst = src0;
349 }
350 
351 always_inline void
352 ip4_tcp_reply_x2 (ip4_header_t * ip0, ip4_header_t * ip1,
353  tcp_header_t * tcp0, tcp_header_t * tcp1)
354 {
355  u32 src0, dst0, src1, dst1;
356 
357  src0 = ip0->src_address.data_u32;
358  src1 = ip1->src_address.data_u32;
359  dst0 = ip0->dst_address.data_u32;
360  dst1 = ip1->dst_address.data_u32;
361  ip0->src_address.data_u32 = dst0;
362  ip1->src_address.data_u32 = dst1;
363  ip0->dst_address.data_u32 = src0;
364  ip1->dst_address.data_u32 = src1;
365 
366  src0 = tcp0->ports.src;
367  src1 = tcp1->ports.src;
368  dst0 = tcp0->ports.dst;
369  dst1 = tcp1->ports.dst;
370  tcp0->ports.src = dst0;
371  tcp1->ports.src = dst1;
372  tcp0->ports.dst = src0;
373  tcp1->ports.dst = src1;
374 }
375 
376 #endif /* included_ip4_packet_h */
377 
378 /*
379  * fd.io coding-style-patch-verification: ON
380  *
381  * Local Variables:
382  * eval: (c-set-style "gnu")
383  * End:
384  */
ip4_address_t ip4_addr
Definition: ip4_packet.h:61
sll srl srl sll sra u16x4 i
Definition: vector_sse2.h:343
a
Definition: bitmap.h:516
ip4_address_t src_address
Definition: ip4_packet.h:163
static int ip4_header_bytes(ip4_header_t *i)
Definition: ip4_packet.h:226
uword ip_csum_t
Definition: ip_packet.h:90
u16 flags_and_fragment_offset
Definition: ip4_packet.h:144
static void ip4_tcp_reply_x1(ip4_header_t *ip0, tcp_header_t *tcp0)
Definition: ip4_packet.h:336
static uword ip4_header_checksum_is_valid(ip4_header_t *i)
Definition: ip4_packet.h:259
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:84
static uword ip4_address_netmask_length(ip4_address_t *a)
Definition: ip4_packet.h:81
ip4_address_t dst_address
Definition: ip4_packet.h:163
static int ip4_get_fragment_offset(ip4_header_t *i)
Definition: ip4_packet.h:191
unsigned long u64
Definition: types.h:89
static void * ip4_next_header(ip4_header_t *i)
Definition: ip4_packet.h:232
static int ip4_is_fragment(ip4_header_t *i)
Definition: ip4_packet.h:204
ip4_address_pair_t address_pair
Definition: ip4_packet.h:165
static uword ip4_address_is_multicast(ip4_address_t *a)
Definition: ip4_packet.h:309
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:352
#define IP4_HEADER_FLAG_MORE_FRAGMENTS
Definition: ip4_packet.h:145
static void ip4_multicast_ethernet_address(u8 *ethernet_address, ip4_address_t *a)
Definition: ip4_packet.h:323
union tcp_header_t::@180::@182 ports
ip4_address_t src
Definition: ip4_packet.h:76
#define clib_memcpy(a, b, c)
Definition: string.h:69
static int ip4_is_first_fragment(ip4_header_t *i)
Definition: ip4_packet.h:211
#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:66
#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:315
static int ip4_get_fragment_more(ip4_header_t *i)
Definition: ip4_packet.h:197
u64 uword
Definition: types.h:112
static int ip4_get_fragment_offset_bytes(ip4_header_t *i)
Definition: ip4_packet.h:220
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:131
static u16 ip4_header_checksum(ip4_header_t *i)
Definition: ip4_packet.h:238
static u16 ip_csum_fold(ip_csum_t c)
Definition: ip_packet.h:145
#define CLIB_PACKED(x)
Definition: clib.h:78