kernel/core/net/checksum.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2008  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *  Copyright (C) 2010  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <system.h>
  21 #include <string.h>
  22 #include <net/if.h>
  23 #include <net/eth.h>
  24 #include <net/packet.h>
  25
  26 static char buf_prealloc[NET_PACKET_MTU + 64];
  27
  28 unsigned short checksum16_ones (unsigned sum, const void *_buf, int len)
  29 {
  30         const unsigned short *buf = _buf;
  31
  32         while (len >= 2) {
  33                 sum += *buf ++;
  34
  35                 if (sum & 0x80000000)
  36                         sum = (sum & 0xffff) + (sum >> 16);
  37
  38                 len -= 2;
  39         }
  40
  41         if (len) {
  42                 unsigned char temp[2];
  43
  44                 temp[0] = *(unsigned char *) buf;
  45                 temp[1] = 0;
  46
  47                 sum += *(unsigned short *) temp;
  48         }
  49
  50         while (sum >> 16)
  51                 sum = (sum & 0xffff) + (sum >> 16);
  52
  53         return sum;
  54 }
  55
  56 unsigned short checksum16 (void *_buf, int len)
  57 {
  58         return ~checksum16_ones (0, _buf, len);
  59 }
  60
  61 unsigned short checksum16_2 (void *buf1, int len1, void *buf2, int len2)
  62 {
  63         unsigned sum;
  64
  65         sum = checksum16_ones (0, buf1, len1);
  66
  67         return ~checksum16_ones (sum, buf2, len2);
  68 }
  69
  70 /* pseudo-header for tcp checksum */
  71 typedef struct proto_tcp_pseudo_t {
  72         unsigned ip_source;
  73         unsigned ip_dest;
  74         unsigned char zero;
  75         unsigned char proto;
  76         unsigned short tcp_len;
  77 } proto_tcp_pseudo_t;
  78
  79 unsigned short checksum16_tcp (unsigned ip_source, unsigned ip_dest, char *buf, unsigned short len)
  80 {
  81         char *buf_pseudo = (char *) &buf_prealloc;
  82
  83         if (!buf_pseudo)
  84                 return 0;
  85
  86         proto_tcp_pseudo_t *pseudo = (proto_tcp_pseudo_t *) buf_pseudo;
  87
  88         pseudo->ip_source = ip_source;
  89         pseudo->ip_dest = ip_dest;
  90         pseudo->tcp_len = swap16 (len);
  91         pseudo->proto = 0x6;
  92         pseudo->zero = 0x0;
  93
  94         memcpy (buf_pseudo+12, buf, len);
  95
  96         buf_pseudo[len+12] = '\0';
  97
  98         unsigned short ret = checksum16 (buf_pseudo, len+12);
  99
 100         return ret;
 101 }
 102
 103 unsigned short checksum16_udp (unsigned ip_source, unsigned ip_dest, char *buf, unsigned short len)
 104 {
 105         char *buf_pseudo = (char *) &buf_prealloc;
 106
 107         if (!buf_pseudo)
 108                 return 0;
 109
 110         proto_tcp_pseudo_t *pseudo = (proto_tcp_pseudo_t *) buf_pseudo;
 111
 112         pseudo->ip_source = ip_source;
 113         pseudo->ip_dest = ip_dest;
 114         pseudo->tcp_len = swap16 (len);
 115         pseudo->proto = 0x11;
 116         pseudo->zero = 0x0;
 117
 118         memcpy (buf_pseudo+12, buf, len);
 119
 120         buf_pseudo[len+12] = '\0';
 121
 122         unsigned short ret = checksum16 (buf_pseudo, len+12);
 123
 124         return ret;
 125 }
 126
 127 /* pseudo-header for icmp6 checksum */
 128 typedef struct proto_ipv6_pseudo_t {
 129         unsigned short ip_source[8];
 130         unsigned short ip_dest[8];
 131         unsigned pl_len;
 132         unsigned zero:24;
 133         unsigned char next_head;
 134 } proto_ipv6_pseudo_t;
 135
 136 unsigned short checksum16_ipv6 (unsigned short ip_source[8], unsigned short ip_dest[8], char *buf, unsigned len, unsigned char proto)
 137 {
 138         char *buf_pseudo = (char *) &buf_prealloc;
 139
 140         if (!buf_pseudo)
 141                 return 0;
 142
 143         proto_ipv6_pseudo_t *pseudo = (proto_ipv6_pseudo_t *) buf_pseudo;
 144
 145         memcpy (pseudo->ip_source, ip_source, 16);
 146         memcpy (pseudo->ip_dest, ip_dest, 16);
 147
 148         pseudo->pl_len = swap32 (len);
 149         pseudo->zero = 0x0;
 150         pseudo->next_head = proto;
 151
 152         //printf ("ipv6 source -> %x:%x:::\n", swap16 (pseudo->ip_source[0]), swap16 (pseudo->ip_source[1]));
 153         //printf ("ipv6 dest -> %x:%x:::\n", swap16 (pseudo->ip_dest[0]), swap16 (pseudo->ip_dest[1]));
 154         //printf ("proto_ipv6_pseudo_t size: %d\n", sizeof (proto_ipv6_pseudo_t));
 155
 156         memcpy (buf_pseudo+40, buf, len);
 157
 158         buf_pseudo[len+40] = '\0';
 159
 160         unsigned short ret = checksum16 (buf_pseudo, len+40);
 161
 162         return ret;
 163 }