pimd/pim_util.c

   1 /*
   2  * PIM for Quagga
   3  * Copyright (C) 2008  Everton da Silva Marques
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <zebra.h>
  21
  22 #include "log.h"
  23 #include "prefix.h"
  24
  25 #include "pim_util.h"
  26
  27 /*
  28   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  29
  30   If QQIC < 128,  QQI = QQIC
  31   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  32
  33   0 1 2 3 4 5 6 7
  34   +-+-+-+-+-+-+-+-+
  35   |1| exp | mant  |
  36   +-+-+-+-+-+-+-+-+
  37
  38   Since exp=0..7 then (exp+3)=3..10, then QQI has
  39   one of the following bit patterns:
  40
  41   exp=0: QQI = 0000.0000.1MMM.M000
  42   exp=1: QQI = 0000.0001.MMMM.0000
  43   ...
  44   exp=6: QQI = 001M.MMM0.0000.0000
  45   exp=7: QQI = 01MM.MM00.0000.0000
  46   --------- ---------
  47   0x4  0x0  0x0  0x0
  48 */
  49 uint8_t igmp_msg_encode16to8(uint16_t value)
  50 {
  51         uint8_t code;
  52
  53         if (value < 128) {
  54                 code = value;
  55         } else {
  56                 uint16_t mask = 0x4000;
  57                 uint8_t exp;
  58                 uint16_t mant;
  59                 for (exp = 7; exp > 0; --exp) {
  60                         if (mask & value)
  61                                 break;
  62                         mask >>= 1;
  63                 }
  64                 mant = 0x000F & (value >> (exp + 3));
  65                 code = ((uint8_t)1 << 7) | ((uint8_t)exp << 4) | (uint8_t)mant;
  66         }
  67
  68         return code;
  69 }
  70
  71 /*
  72   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  73
  74   If QQIC < 128,  QQI = QQIC
  75   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  76
  77   0 1 2 3 4 5 6 7
  78   +-+-+-+-+-+-+-+-+
  79   |1| exp | mant  |
  80   +-+-+-+-+-+-+-+-+
  81 */
  82 uint16_t igmp_msg_decode8to16(uint8_t code)
  83 {
  84         uint16_t value;
  85
  86         if (code < 128) {
  87                 value = code;
  88         } else {
  89                 uint16_t mant = (code & 0x0F);
  90                 uint8_t exp = (code & 0x70) >> 4;
  91                 value = (mant | 0x10) << (exp + 3);
  92         }
  93
  94         return value;
  95 }
  96
  97 void pim_pkt_dump(const char *label, const uint8_t *buf, int size)
  98 {
  99         zlog_debug("%s: pkt dump size=%d", label, size);
 100         zlog_hexdump(buf, size);
 101 }
 102
 103 int pim_is_group_224_0_0_0_24(struct in_addr group_addr)
 104 {
 105         static int first = 1;
 106         static struct prefix group_224;
 107         struct prefix group;
 108
 109         if (first) {
 110                 if (!str2prefix("224.0.0.0/24", &group_224))
 111                         return 0;
 112                 first = 0;
 113         }
 114
 115         group.family = AF_INET;
 116         group.u.prefix4 = group_addr;
 117         group.prefixlen = 32;
 118
 119         return prefix_match(&group_224, &group);
 120 }
 121
 122 int pim_is_group_224_4(struct in_addr group_addr)
 123 {
 124         static int first = 1;
 125         static struct prefix group_all;
 126         struct prefix group;
 127
 128         if (first) {
 129                 if (!str2prefix("224.0.0.0/4", &group_all))
 130                         return 0;
 131                 first = 0;
 132         }
 133
 134         group.family = AF_INET;
 135         group.u.prefix4 = group_addr;
 136         group.prefixlen = 32;
 137
 138         return prefix_match(&group_all, &group);
 139 }