/* * 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 /* for ip_csum_t */ #include /* for tcp_header_t */ #include /* 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, ip4_address_t * address, u32 fib_index) { clib_memcpy (&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; /* If address is a valid netmask, return length of mask. */ always_inline uword ip4_address_netmask_length (ip4_address_t * a) { uword result = 0; uword i; for (i = 0; i < ARRAY_LEN (a->as_u8); i++) { switch (a->as_u8[i]) { case 0xff: result += 8; break; case 0xfe: result += 7; goto done; case 0xfc: result += 6; goto done; case 0xf8: result += 5; goto done; case 0xf0: result += 4; goto done; case 0xe0: result += 3; goto done; case 0xc0: result += 2; goto done; case 0x80: result += 1; goto done; case 0x00: result += 0; goto done; default: /* Not a valid netmask mask. */ return ~0; } } done: return result; } 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. */ u8 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))) always_inline int ip4_get_fragment_offset (ip4_header_t * i) { return clib_net_to_host_u16 (i->flags_and_fragment_offset) & 0x1fff; } always_inline int ip4_get_fragment_more (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 (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 (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 (ip4_header_t * i) { return 8 * ip4_get_fragment_offset (i); } always_inline int ip4_header_bytes (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) { u16 save, csum; ip_csum_t sum; save = i->checksum; i->checksum = 0; sum = ip_incremental_checksum (0, i, ip4_header_bytes (i)); csum = ~ip_csum_fold (sum); i->checksum = save; /* Make checksum agree for special case where either 0 or 0xffff would give same 1s complement sum. */ if (csum == 0 && save == 0xffff) csum = save; return csum; } 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