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 #include "plist.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         } else {
  57                 uint16_t mask = 0x4000;
  58                 uint8_t exp;
  59                 uint16_t mant;
  60                 for (exp = 7; exp > 0; --exp) {
  61                         if (mask & value)
  62                                 break;
  63                         mask >>= 1;
  64                 }
  65                 mant = 0x000F & (value >> (exp + 3));
  66                 code = ((uint8_t)1 << 7) | ((uint8_t)exp << 4) | (uint8_t)mant;
  67         }
  68
  69         return code;
  70 }
  71
  72 /*
  73   RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
  74
  75   If QQIC < 128,  QQI = QQIC
  76   If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
  77
  78   0 1 2 3 4 5 6 7
  79   +-+-+-+-+-+-+-+-+
  80   |1| exp | mant  |
  81   +-+-+-+-+-+-+-+-+
  82 */
  83 uint16_t igmp_msg_decode8to16(uint8_t code)
  84 {
  85         uint16_t value;
  86
  87         if (code < 128) {
  88                 value = code;
  89         } else {
  90                 uint16_t mant = (code & 0x0F);
  91                 uint8_t exp = (code & 0x70) >> 4;
  92                 value = (mant | 0x10) << (exp + 3);
  93         }
  94
  95         return value;
  96 }
  97
  98 void pim_pkt_dump(const char *label, const uint8_t *buf, int size)
  99 {
 100         zlog_debug("%s: pkt dump size=%d", label, size);
 101         zlog_hexdump(buf, size);
 102 }
 103
 104 int pim_is_group_224_0_0_0_24(struct in_addr group_addr)
 105 {
 106         static int first = 1;
 107         static struct prefix group_224;
 108         struct prefix group;
 109
 110         if (first) {
 111                 if (!str2prefix("224.0.0.0/24", &group_224))
 112                         return 0;
 113                 first = 0;
 114         }
 115
 116         group.family = AF_INET;
 117         group.u.prefix4 = group_addr;
 118         group.prefixlen = IPV4_MAX_PREFIXLEN;
 119
 120         return prefix_match(&group_224, &group);
 121 }
 122
 123 int pim_is_group_224_4(struct in_addr group_addr)
 124 {
 125         static int first = 1;
 126         static struct prefix group_all;
 127         struct prefix group;
 128
 129         if (first) {
 130                 if (!str2prefix("224.0.0.0/4", &group_all))
 131                         return 0;
 132                 first = 0;
 133         }
 134
 135         group.family = AF_INET;
 136         group.u.prefix4 = group_addr;
 137         group.prefixlen = 32;
 138
 139         return prefix_match(&group_all, &group);
 140 }
 141
 142 bool pim_is_group_filtered(struct pim_interface *pim_ifp, struct in_addr *grp)
 143 {
 144         struct prefix grp_pfx;
 145         struct prefix_list *pl;
 146
 147         if (!pim_ifp->boundary_oil_plist)
 148                 return false;
 149
 150         grp_pfx.family = AF_INET;
 151         grp_pfx.prefixlen = 32;
 152         grp_pfx.u.prefix4 = *grp;
 153
 154         pl = prefix_list_lookup(AFI_IP, pim_ifp->boundary_oil_plist);
 155         return pl ? prefix_list_apply(pl, &grp_pfx) == PREFIX_DENY : false;
 156 }