pimd/pim_msg.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 "if.h"
  24
  25 #include "pimd.h"
  26 #include "pim_pim.h"
  27 #include "pim_msg.h"
  28 #include "pim_util.h"
  29
  30 void pim_msg_build_header(uint8_t *pim_msg, int pim_msg_size,
  31                           uint8_t pim_msg_type)
  32 {
  33   uint16_t checksum;
  34
  35   zassert(pim_msg_size >= PIM_PIM_MIN_LEN);
  36
  37   /*
  38    * Write header
  39    */
  40
  41   *(uint8_t *) PIM_MSG_HDR_OFFSET_VERSION(pim_msg) = (PIM_PROTO_VERSION << 4) | pim_msg_type;
  42   *(uint8_t *) PIM_MSG_HDR_OFFSET_RESERVED(pim_msg) = 0;
  43
  44   /*
  45    * Compute checksum
  46    */
  47
  48   *(uint16_t *) PIM_MSG_HDR_OFFSET_CHECKSUM(pim_msg) = 0;
  49   checksum = in_cksum(pim_msg, pim_msg_size);
  50   *(uint16_t *) PIM_MSG_HDR_OFFSET_CHECKSUM(pim_msg) = checksum;
  51 }
  52
  53 uint8_t *pim_msg_addr_encode_ipv4_ucast(uint8_t *buf,
  54                                         int buf_size,
  55                                         struct in_addr addr)
  56 {
  57   const int ENCODED_IPV4_UCAST_SIZE = 6;
  58
  59   if (buf_size < ENCODED_IPV4_UCAST_SIZE) {
  60     return 0;
  61   }
  62
  63   buf[0] = PIM_MSG_ADDRESS_FAMILY_IPV4; /* addr family */
  64   buf[1] = '\0';    /* native encoding */
  65   memcpy(buf+2, &addr, sizeof(struct in_addr));
  66
  67   return buf + ENCODED_IPV4_UCAST_SIZE;
  68 }
  69
  70 uint8_t *pim_msg_addr_encode_ipv4_group(uint8_t *buf,
  71                                         int buf_size,
  72                                         struct in_addr addr)
  73 {
  74   const int ENCODED_IPV4_GROUP_SIZE = 8;
  75
  76   if (buf_size < ENCODED_IPV4_GROUP_SIZE) {
  77     return 0;
  78   }
  79
  80   buf[0] = PIM_MSG_ADDRESS_FAMILY_IPV4; /* addr family */
  81   buf[1] = '\0';    /* native encoding */
  82   buf[2] = '\0';    /* reserved */
  83   buf[3] = 32;      /* mask len */
  84   memcpy(buf+4, &addr, sizeof(struct in_addr));
  85
  86   return buf + ENCODED_IPV4_GROUP_SIZE;
  87 }
  88
  89 uint8_t *pim_msg_addr_encode_ipv4_source(uint8_t *buf,
  90                                          int buf_size,
  91                                          struct in_addr addr)
  92 {
  93   const int ENCODED_IPV4_SOURCE_SIZE = 8;
  94
  95   if (buf_size < ENCODED_IPV4_SOURCE_SIZE) {
  96     return 0;
  97   }
  98
  99   buf[0] = PIM_MSG_ADDRESS_FAMILY_IPV4; /* addr family */
 100   buf[1] = '\0';    /* native encoding */
 101   buf[2] = 4;       /* reserved = 0 | S bit = 1 | W bit = 0 | R bit = 0 */
 102   buf[3] = 32;      /* mask len */
 103   memcpy(buf+4, &addr, sizeof(struct in_addr));
 104
 105   return buf + ENCODED_IPV4_SOURCE_SIZE;
 106 }