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
  16   along with this program; see the file COPYING; if not, write to the
  17   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  18   MA 02110-1301 USA
  19 */
  20
  21 #include <zebra.h>
  22
  23 #include "log.h"
  24 #include "prefix.h"
  25
  26 #include "pim_util.h"
  27
  28 /*
  29   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  30
  31   If QQIC < 128,  QQI = QQIC
  32   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  33
  34   0 1 2 3 4 5 6 7
  35   +-+-+-+-+-+-+-+-+
  36   |1| exp | mant  |
  37   +-+-+-+-+-+-+-+-+
  38
  39   Since exp=0..7 then (exp+3)=3..10, then QQI has
  40   one of the following bit patterns:
  41
  42   exp=0: QQI = 0000.0000.1MMM.M000
  43   exp=1: QQI = 0000.0001.MMMM.0000
  44   ...
  45   exp=6: QQI = 001M.MMM0.0000.0000
  46   exp=7: QQI = 01MM.MM00.0000.0000
  47   --------- ---------
  48   0x4  0x0  0x0  0x0
  49 */
  50 uint8_t igmp_msg_encode16to8(uint16_t value)
  51 {
  52   uint8_t code;
  53
  54   if (value < 128) {
  55     code = value;
  56   }
  57   else {
  58     uint16_t mask = 0x4000;
  59     uint8_t  exp;
  60     uint16_t mant;
  61     for (exp = 7; exp > 0; --exp) {
  62       if (mask & value)
  63         break;
  64       mask >>= 1;
  65     }
  66     mant = 0x000F & (value >> (exp + 3));
  67     code = ((uint8_t) 1 << 7) | ((uint8_t) exp << 4) | (uint8_t) mant;
  68   }
  69
  70   return code;
  71 }
  72
  73 /*
  74   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  75
  76   If QQIC < 128,  QQI = QQIC
  77   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  78
  79   0 1 2 3 4 5 6 7
  80   +-+-+-+-+-+-+-+-+
  81   |1| exp | mant  |
  82   +-+-+-+-+-+-+-+-+
  83 */
  84 uint16_t igmp_msg_decode8to16(uint8_t code)
  85 {
  86   uint16_t value;
  87
  88   if (code < 128) {
  89     value = code;
  90   }
  91   else {
  92     uint16_t mant = (code & 0x0F);
  93     uint8_t  exp  = (code & 0x70) >> 4;
  94     value = (mant | 0x10) << (exp + 3);
  95   }
  96
  97   return value;
  98 }
  99
 100 void pim_pkt_dump(const char *label, const uint8_t *buf, int size)
 101 {
 102   zlog_debug("%s: pkt dump size=%d",
 103              label,
 104              size);
 105   zlog_hexdump(buf, size);
 106 }
 107
 108 int
 109 pim_is_group_224_0_0_0_24 (struct in_addr group_addr)
 110 {
 111   static int first = 1;
 112   static struct prefix group_224;
 113   struct prefix group;
 114
 115   if (first)
 116     {
 117       str2prefix ("224.0.0.0/24", &group_224);
 118       first = 0;
 119     }
 120
 121   group.family = AF_INET;
 122   group.u.prefix4 = group_addr;
 123   group.prefixlen = 32;
 124
 125   return prefix_match (&group_224, &group);
 126 }
 127
 128 int
 129 pim_is_group_224_4 (struct in_addr group_addr)
 130 {
 131   static int first = 1;
 132   static struct prefix group_all;
 133   struct prefix group;
 134
 135   if (first)
 136     {
 137       str2prefix ("224.0.0.0/4", &group_all);
 138       first = 0;
 139     }
 140
 141   group.family = AF_INET;
 142   group.u.prefix4 = group_addr;
 143   group.prefixlen = 32;
 144
 145   return prefix_match (&group_all, &group);
 146 }