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
  22 #include <zebra.h>
  23
  24 #include "if.h"
  25
  26 #include "pimd.h"
  27 #include "pim_pim.h"
  28 #include "pim_msg.h"
  29 #include "pim_util.h"
  30
  31 void pim_msg_build_header(uint8_t *pim_msg, int pim_msg_size,
  32                           uint8_t pim_msg_type)
  33 {
  34   uint16_t checksum;
  35
  36   zassert(pim_msg_size >= PIM_PIM_MIN_LEN);
  37
  38   /*
  39    * Write header
  40    */
  41
  42   *(uint8_t *) PIM_MSG_HDR_OFFSET_VERSION(pim_msg) = (PIM_PROTO_VERSION << 4) | pim_msg_type;
  43   *(uint8_t *) PIM_MSG_HDR_OFFSET_RESERVED(pim_msg) = 0;
  44
  45   /*
  46    * Compute checksum
  47    */
  48
  49   *(uint16_t *) PIM_MSG_HDR_OFFSET_CHECKSUM(pim_msg) = 0;
  50   checksum = in_cksum(pim_msg, pim_msg_size);
  51   *(uint16_t *) PIM_MSG_HDR_OFFSET_CHECKSUM(pim_msg) = checksum;
  52 }
  53
  54 uint8_t *pim_msg_addr_encode_ipv4_ucast(uint8_t *buf,
  55                                         int buf_size,
  56                                         struct in_addr addr)
  57 {
  58   const int ENCODED_IPV4_UCAST_SIZE = 6;
  59
  60   if (buf_size < ENCODED_IPV4_UCAST_SIZE) {
  61     return 0;
  62   }
  63
  64   buf[0] = PIM_MSG_ADDRESS_FAMILY_IPV4; /* addr family */
  65   buf[1] = '\0';    /* native encoding */
  66   memcpy(buf+2, &addr, sizeof(struct in_addr));
  67
  68   return buf + ENCODED_IPV4_UCAST_SIZE;
  69 }
  70
  71 uint8_t *pim_msg_addr_encode_ipv4_group(uint8_t *buf,
  72                                         int buf_size,
  73                                         struct in_addr addr)
  74 {
  75   const int ENCODED_IPV4_GROUP_SIZE = 8;
  76
  77   if (buf_size < ENCODED_IPV4_GROUP_SIZE) {
  78     return 0;
  79   }
  80
  81   buf[0] = PIM_MSG_ADDRESS_FAMILY_IPV4; /* addr family */
  82   buf[1] = '\0';    /* native encoding */
  83   buf[2] = '\0';    /* reserved */
  84   buf[3] = 32;      /* mask len */
  85   memcpy(buf+4, &addr, sizeof(struct in_addr));
  86
  87   return buf + ENCODED_IPV4_GROUP_SIZE;
  88 }
  89
  90 uint8_t *pim_msg_addr_encode_ipv4_source(uint8_t *buf,
  91                                          int buf_size,
  92                                          struct in_addr addr)
  93 {
  94   const int ENCODED_IPV4_SOURCE_SIZE = 8;
  95
  96   if (buf_size < ENCODED_IPV4_SOURCE_SIZE) {
  97     return 0;
  98   }
  99
 100   buf[0] = PIM_MSG_ADDRESS_FAMILY_IPV4; /* addr family */
 101   buf[1] = '\0';    /* native encoding */
 102   buf[2] = 4;       /* reserved = 0 | S bit = 1 | W bit = 0 | R bit = 0 */
 103   buf[3] = 32;      /* mask len */
 104   memcpy(buf+4, &addr, sizeof(struct in_addr));
 105
 106   return buf + ENCODED_IPV4_SOURCE_SIZE;
 107 }