net/sctp/sla1.c

   1 /* SCTP kernel reference Implementation
   2  * Copyright (c) 1999-2000 Cisco, Inc.
   3  * Copyright (c) 1999-2001 Motorola, Inc.
   4  *
   5  * This file is part of the SCTP kernel reference Implementation
   6  *
   7  * (It's really SHA-1 but Hey I was tired when I created this
   8  * file, and on a plane to France :-)
   9  *
  10  * The SCTP reference implementation is free software;
  11  * you can redistribute it and/or modify it under the terms of
  12  * the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * The SCTP reference implementation is distributed in the hope that it
  17  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  18  *                 ************************
  19  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  20  * See the GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with GNU CC; see the file COPYING.  If not, write to
  24  * the Free Software Foundation, 59 Temple Place - Suite 330,
  25  * Boston, MA 02111-1307, USA.
  26  *
  27  * Please send any bug reports or fixes you make to the
  28  * email address(es):
  29  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  30  *
  31  * Or submit a bug report through the following website:
  32  *    http://www.sf.net/projects/lksctp
  33  *
  34  * Written or modified by:
  35  *    Randall Stewart <rstewar1@email.mot.com>
  36  *    kmorneau@cisco.com
  37  *    qxie1@email.mot.com
  38  *
  39  * Based on:
  40  *    Randy Stewart, et al. SCTP Reference Implementation which is licenced
  41  *    under the GPL.
  42  *
  43  * Any bugs reported given to us we will try to fix... any fixes shared will
  44  * be incorporated into the next SCTP release.
  45  */
  46
  47 #include <linux/types.h>
  48 #include <linux/kernel.h>
  49 #include <linux/fcntl.h>
  50 #include <asm/string.h>         /* for memcpy */
  51 #include <linux/sched.h>        /* dead chicken for in.h */
  52 #include <linux/in.h>           /* for htonl and ntohl */
  53
  54 #include <net/sctp/sla1.h>
  55
  56 void SLA1_Init(struct SLA_1_Context *ctx)
  57 {
  58         /* Init the SLA-1 context structure.  */
  59         ctx->A = 0;
  60         ctx->B = 0;
  61         ctx->C = 0;
  62         ctx->D = 0;
  63         ctx->E = 0;
  64         ctx->H0 = H0INIT;
  65         ctx->H1 = H1INIT;
  66         ctx->H2 = H2INIT;
  67         ctx->H3 = H3INIT;
  68         ctx->H4 = H4INIT;
  69         ctx->TEMP = 0;
  70         memset(ctx->words, 0, sizeof(ctx->words));
  71         ctx->howManyInBlock = 0;
  72         ctx->runningTotal = 0;
  73 }
  74
  75 void SLA1processABlock(struct SLA_1_Context *ctx,unsigned int *block)
  76 {
  77         int i;
  78         /* init the W0-W15 to the block of words being
  79          * hashed.
  80          */
  81         /* step a) */
  82
  83         for (i = 0; i < 16; i++)
  84                 ctx->words[i] = ntohl(block[i]);
  85
  86         /* now init the rest based on the SLA-1 formula, step b) */
  87         for (i = 16; i < 80; i++)
  88                 ctx->words[i] =
  89                         CSHIFT(1, ((ctx->words[(i-3)]) ^
  90                                    (ctx->words[(i-8)]) ^
  91                                    (ctx->words[(i-14)]) ^
  92                                    (ctx->words[(i-16)])));
  93
  94         /* step c) */
  95         ctx->A = ctx->H0;
  96         ctx->B = ctx->H1;
  97         ctx->C = ctx->H2;
  98         ctx->D = ctx->H3;
  99         ctx->E = ctx->H4;
 100
 101         /* step d) */
 102         for (i = 0; i < 80; i++) {
 103                 if (i < 20) {
 104                         ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 105                                      (F1(ctx->B, ctx->C, ctx->D)) +
 106                                      (ctx->E) +
 107                                      ctx->words[i] +
 108                                      K1
 109                                 );
 110                 } else if (i < 40) {
 111                         ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 112                                      (F2(ctx->B, ctx->C, ctx->D)) +
 113                                      (ctx->E) +
 114                                      (ctx->words[i]) +
 115                                      K2
 116                                 );
 117                 } else if (i < 60) {
 118                         ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 119                                      (F3(ctx->B, ctx->C, ctx->D)) +
 120                                      (ctx->E) +
 121                                      (ctx->words[i]) +
 122                                      K3
 123                                 );
 124                 } else {
 125                         ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 126                                      (F4(ctx->B, ctx->C, ctx->D)) +
 127                                      (ctx->E) +
 128                                      (ctx->words[i]) +
 129                                      K4
 130                                 );
 131                 }
 132                 ctx->E = ctx->D;
 133                 ctx->D = ctx->C;
 134                 ctx->C = CSHIFT(30, ctx->B);
 135                 ctx->B = ctx->A;
 136                 ctx->A = ctx->TEMP;
 137         }
 138
 139         /* step e) */
 140         ctx->H0 = (ctx->H0) + (ctx->A);
 141         ctx->H1 = (ctx->H1) + (ctx->B);
 142         ctx->H2 = (ctx->H2) + (ctx->C);
 143         ctx->H3 = (ctx->H3) + (ctx->D);
 144         ctx->H4 = (ctx->H4) + (ctx->E);
 145 }
 146
 147 void SLA1_Process(struct SLA_1_Context *ctx, const unsigned char *ptr, int siz)
 148 {
 149         int numberLeft, leftToFill;
 150
 151         numberLeft = siz;
 152         while (numberLeft > 0) {
 153                 leftToFill = sizeof(ctx->SLAblock) - ctx->howManyInBlock;
 154                 if (leftToFill > numberLeft) {
 155                         /* can only partially fill up this one */
 156                         memcpy(&ctx->SLAblock[ctx->howManyInBlock],
 157                                ptr, numberLeft);
 158                         ctx->howManyInBlock += siz;
 159                         ctx->runningTotal += siz;
 160                         break;
 161                 } else {
 162                         /* block is now full, process it */
 163                         memcpy(&ctx->SLAblock[ctx->howManyInBlock],
 164                                ptr, leftToFill);
 165                         SLA1processABlock(ctx, (unsigned int *) ctx->SLAblock);
 166                         numberLeft -= leftToFill;
 167                         ctx->runningTotal += leftToFill;
 168                         ctx->howManyInBlock = 0;
 169                 }
 170         }
 171 }
 172
 173 void SLA1_Final(struct SLA_1_Context *ctx, unsigned char *digestBuf)
 174 {
 175         /* if any left in block fill with padding
 176          * and process. Then transfer the digest to
 177          * the pointer. At the last block some special
 178          * rules need to apply. We must add a 1 bit
 179          * following the message, then we pad with
 180          * 0's. The total size is encoded as a 64 bit
 181          * number at the end. Now if the last buffer has
 182          * more than 55 octets in it we cannot fit
 183          * the 64 bit number + 10000000 pad on the end
 184          * and must add the 10000000 pad, pad the rest
 185          * of the message with 0's and then create a
 186          * all 0 message with just the 64 bit size
 187          * at the end and run this block through by itself.
 188          * Also the 64 bit int must be in network byte
 189          * order.
 190          */
 191         int i, leftToFill;
 192         unsigned int *ptr;
 193
 194         if (ctx->howManyInBlock > 55) {
 195                 /* special case, we need to process two
 196                  * blocks here. One for the current stuff
 197                  * plus possibly the pad. The other for
 198                  * the size.
 199                  */
 200                 leftToFill = sizeof(ctx->SLAblock) - ctx->howManyInBlock;
 201                 if (leftToFill == 0) {
 202                         /* Should not really happen but I am paranoid */
 203                         /* Not paranoid enough!  It is possible for leftToFill
 204                          * to become negative!  AAA!!!!  This is another reason
 205                          * to pick MD5 :-)...
 206                          */
 207                         SLA1processABlock(ctx, (unsigned int *) ctx->SLAblock);
 208                         /* init last block, a bit different then the rest :-) */
 209                         ctx->SLAblock[0] = 0x80;
 210                         for (i = 1; i < sizeof(ctx->SLAblock); i++) {
 211                                 ctx->SLAblock[i] = 0x0;
 212                         }
 213                 } else if (leftToFill == 1) {
 214                         ctx->SLAblock[ctx->howManyInBlock] = 0x80;
 215                         SLA1processABlock(ctx, (unsigned int *) ctx->SLAblock);
 216                         /* init last block */
 217                         memset(ctx->SLAblock, 0, sizeof(ctx->SLAblock));
 218                 } else {
 219                         ctx->SLAblock[ctx->howManyInBlock] = 0x80;
 220                         for (i = (ctx->howManyInBlock + 1);
 221                              i < sizeof(ctx->SLAblock);
 222                              i++) {
 223                                 ctx->SLAblock[i] = 0x0;
 224                         }
 225                         SLA1processABlock(ctx, (unsigned int *) ctx->SLAblock);
 226                         /* init last block */
 227                         memset(ctx->SLAblock, 0, sizeof(ctx->SLAblock));
 228                 }
 229                 /* This is in bits so multiply by 8 */
 230                 ctx->runningTotal *= 8;
 231                 ptr = (unsigned int *) &ctx->SLAblock[60];
 232                 *ptr = htonl(ctx->runningTotal);
 233                 SLA1processABlock(ctx, (unsigned int *) ctx->SLAblock);
 234         } else {
 235                 /* easy case, we just pad this
 236                  * message to size - end with 0
 237                  * add the magic 0x80 to the next
 238                  * word and then put the network byte
 239                  * order size in the last spot and
 240                  * process the block.
 241                  */
 242                 ctx->SLAblock[ctx->howManyInBlock] = 0x80;
 243                 for (i = (ctx->howManyInBlock + 1);
 244                      i < sizeof(ctx->SLAblock);
 245                      i++) {
 246                         ctx->SLAblock[i] = 0x0;
 247                 }
 248                 /* get last int spot */
 249                 ctx->runningTotal *= 8;
 250                 ptr = (unsigned int *) &ctx->SLAblock[60];
 251                 *ptr = htonl(ctx->runningTotal);
 252                 SLA1processABlock(ctx, (unsigned int *) ctx->SLAblock);
 253         }
 254         /* Now at this point all we need do is transfer the
 255          * digest back to the user
 256          */
 257         digestBuf[3] = (ctx->H0 & 0xff);
 258         digestBuf[2] = ((ctx->H0 >> 8) & 0xff);
 259         digestBuf[1] = ((ctx->H0 >> 16) & 0xff);
 260         digestBuf[0] = ((ctx->H0 >> 24) & 0xff);
 261
 262         digestBuf[7] = (ctx->H1 & 0xff);
 263         digestBuf[6] = ((ctx->H1 >> 8) & 0xff);
 264         digestBuf[5] = ((ctx->H1 >> 16) & 0xff);
 265         digestBuf[4] = ((ctx->H1 >> 24) & 0xff);
 266
 267         digestBuf[11] = (ctx->H2 & 0xff);
 268         digestBuf[10] = ((ctx->H2 >> 8) & 0xff);
 269         digestBuf[9] = ((ctx->H2 >> 16) & 0xff);
 270         digestBuf[8] = ((ctx->H2 >> 24) & 0xff);
 271
 272         digestBuf[15] = (ctx->H3 & 0xff);
 273         digestBuf[14] = ((ctx->H3 >> 8) & 0xff);
 274         digestBuf[13] = ((ctx->H3 >> 16) & 0xff);
 275         digestBuf[12] = ((ctx->H3 >> 24) & 0xff);
 276
 277         digestBuf[19] = (ctx->H4 & 0xff);
 278         digestBuf[18] = ((ctx->H4 >> 8) & 0xff);
 279         digestBuf[17] = ((ctx->H4 >> 16) & 0xff);
 280         digestBuf[16] = ((ctx->H4 >> 24) & 0xff);
 281 }