src/libfreeswan/ipsec_ah.h

   1 /*
   2  * Authentication Header declarations
   3  * Copyright (C) 1996, 1997  John Ioannidis.
   4  * Copyright (C) 1998, 1999, 2000, 2001  Richard Guy Briggs.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or (at your
   9  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * for more details.
  15  *
  16  * RCSID $Id: ipsec_ah.h,v 1.2 2004/03/22 21:53:18 as Exp $
  17  */
  18
  19 #include "ipsec_md5h.h"
  20 #include "ipsec_sha1.h"
  21
  22 #ifndef IPPROTO_AH
  23 #define IPPROTO_AH 51
  24 #endif /* IPPROTO_AH */
  25
  26 #define AH_FLENGTH              12              /* size of fixed part */
  27 #define AHMD5_KMAX              64              /* MD5 max 512 bits key */
  28 #define AHMD5_AMAX              12              /* MD5 96 bits of authenticator */
  29
  30 #define AHMD596_KLEN            16              /* MD5 128 bits key */
  31 #define AHSHA196_KLEN           20              /* SHA1 160 bits key */
  32
  33 #define AHMD596_ALEN            16              /* MD5 128 bits authentication length */
  34 #define AHSHA196_ALEN           20              /* SHA1 160 bits authentication length */
  35
  36 #define AHMD596_BLKLEN          64              /* MD5 block length */
  37 #define AHSHA196_BLKLEN         64              /* SHA1 block length */
  38 #define AHSHA2_256_BLKLEN       64              /* SHA2-256 block length */
  39 #define AHSHA2_384_BLKLEN       128             /* SHA2-384 block length (?) */
  40 #define AHSHA2_512_BLKLEN       128             /* SHA2-512 block length */
  41
  42 #define AH_BLKLEN_MAX           128             /* keep up to date! */
  43
  44 #define AH_AMAX                 AHSHA196_ALEN   /* keep up to date! */
  45 #define AHHMAC_HASHLEN          12              /* authenticator length of 96bits */
  46 #define AHHMAC_RPLLEN           4               /* 32 bit replay counter */
  47
  48 #define DB_AH_PKTRX             0x0001
  49 #define DB_AH_PKTRX2            0x0002
  50 #define DB_AH_DMP               0x0004
  51 #define DB_AH_IPSA              0x0010
  52 #define DB_AH_XF                0x0020
  53 #define DB_AH_INAU              0x0040
  54 #define DB_AH_REPLAY            0x0100
  55
  56 #ifdef __KERNEL__
  57
  58 /* General HMAC algorithm is described in RFC 2104 */
  59
  60 #define         HMAC_IPAD       0x36
  61 #define         HMAC_OPAD       0x5C
  62
  63 struct md5_ctx {
  64         MD5_CTX ictx;           /* context after H(K XOR ipad) */
  65         MD5_CTX octx;           /* context after H(K XOR opad) */
  66 };
  67
  68 struct sha1_ctx {
  69         SHA1_CTX ictx;          /* context after H(K XOR ipad) */
  70         SHA1_CTX octx;          /* context after H(K XOR opad) */
  71 };
  72
  73 struct auth_alg {
  74         void (*init)(void *ctx);
  75         void (*update)(void *ctx, unsigned char *bytes, __u32 len);
  76         void (*final)(unsigned char *hash, void *ctx);
  77         int hashlen;
  78 };
  79
  80 extern struct inet_protocol ah_protocol;
  81
  82 struct options;
  83
  84 extern int
  85 ah_rcv(struct sk_buff *skb,
  86        struct device *dev,
  87        struct options *opt,
  88        __u32 daddr,
  89        unsigned short len,
  90        __u32 saddr,
  91        int redo,
  92        struct inet_protocol *protocol);
  93
  94 struct ahhdr                            /* Generic AH header */
  95 {
  96         __u8    ah_nh;                  /* Next header (protocol) */
  97         __u8    ah_hl;                  /* AH length, in 32-bit words */
  98         __u16   ah_rv;                  /* reserved, must be 0 */
  99         __u32   ah_spi;                 /* Security Parameters Index */
 100         __u32   ah_rpl;                 /* Replay prevention */
 101         __u8    ah_data[AHHMAC_HASHLEN];/* Authentication hash */
 102 };
 103 #define AH_BASIC_LEN 8      /* basic AH header is 8 bytes, nh,hl,rv,spi
 104                              * and the ah_hl, says how many bytes after that
 105                              * to cover. */
 106
 107
 108 #ifdef CONFIG_IPSEC_DEBUG
 109 extern int debug_ah;
 110 #endif /* CONFIG_IPSEC_DEBUG */
 111 #endif /* __KERNEL__ */