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 <<<<<<< HEAD
  20
  21 =======
  22 >>>>>>> origin/master
  23 */
  24
  25 #include <zebra.h>
  26
  27 #include "log.h"
  28 #include "prefix.h"
  29
  30 #include "pim_util.h"
  31
  32 /*
  33   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  34
  35   If QQIC < 128,  QQI = QQIC
  36   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  37
  38   0 1 2 3 4 5 6 7
  39   +-+-+-+-+-+-+-+-+
  40   |1| exp | mant  |
  41   +-+-+-+-+-+-+-+-+
  42
  43   Since exp=0..7 then (exp+3)=3..10, then QQI has
  44   one of the following bit patterns:
  45
  46   exp=0: QQI = 0000.0000.1MMM.M000
  47   exp=1: QQI = 0000.0001.MMMM.0000
  48   ...
  49   exp=6: QQI = 001M.MMM0.0000.0000
  50   exp=7: QQI = 01MM.MM00.0000.0000
  51   --------- ---------
  52   0x4  0x0  0x0  0x0
  53 */
  54 uint8_t igmp_msg_encode16to8(uint16_t value)
  55 {
  56   uint8_t code;
  57
  58   if (value < 128) {
  59     code = value;
  60   }
  61   else {
  62     uint16_t mask = 0x4000;
  63     uint8_t  exp;
  64     uint16_t mant;
  65     for (exp = 7; exp > 0; --exp) {
  66       if (mask & value)
  67         break;
  68       mask >>= 1;
  69     }
  70     mant = 0x000F & (value >> (exp + 3));
  71     code = ((uint8_t) 1 << 7) | ((uint8_t) exp << 4) | (uint8_t) mant;
  72   }
  73
  74   return code;
  75 }
  76
  77 /*
  78   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  79
  80   If QQIC < 128,  QQI = QQIC
  81   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  82
  83   0 1 2 3 4 5 6 7
  84   +-+-+-+-+-+-+-+-+
  85   |1| exp | mant  |
  86   +-+-+-+-+-+-+-+-+
  87 */
  88 uint16_t igmp_msg_decode8to16(uint8_t code)
  89 {
  90   uint16_t value;
  91
  92   if (code < 128) {
  93     value = code;
  94   }
  95   else {
  96     uint16_t mant = (code & 0x0F);
  97     uint8_t  exp  = (code & 0x70) >> 4;
  98     value = (mant | 0x10) << (exp + 3);
  99   }
 100
 101   return value;
 102 }
 103
 104 void pim_pkt_dump(const char *label, const uint8_t *buf, int size)
 105 {
 106   zlog_debug("%s: pkt dump size=%d",
 107              label,
 108              size);
 109   zlog_hexdump(buf, size);
 110 }
 111
 112 int
 113 pim_is_group_224_0_0_0_24 (struct in_addr group_addr)
 114 {
 115   static int first = 1;
 116   static struct prefix group_224;
 117   struct prefix group;
 118
 119   if (first)
 120     {
 121       str2prefix ("224.0.0.0/24", &group_224);
 122       first = 0;
 123     }
 124
 125   group.family = AF_INET;
 126   group.u.prefix4 = group_addr;
 127   group.prefixlen = 32;
 128
 129   return prefix_match (&group_224, &group);
 130 }
 131
 132 int
 133 pim_is_group_224_4 (struct in_addr group_addr)
 134 {
 135   static int first = 1;
 136   static struct prefix group_all;
 137   struct prefix group;
 138
 139   if (first)
 140     {
 141       str2prefix ("224.0.0.0/4", &group_all);
 142       first = 0;
 143     }
 144
 145   group.family = AF_INET;
 146   group.u.prefix4 = group_addr;
 147   group.prefixlen = 32;
 148
 149   return prefix_match (&group_all, &group);
 150 }