vrrpd/vrrp_packet.h

   1 /*
   2  * VRRPD packet crafting
   3  * Copyright (C) 2018 Cumulus Networks, Inc.
   4  *               Quentin Young
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20 #include <zebra.h>
  21
  22 #include "memory.h"
  23 #include "ipaddr.h"
  24 #include "prefix.h"
  25
  26 #define VRRP_VERSION 3
  27 #define VRRP_TYPE_ADVERTISEMENT 1
  28
  29 /*
  30  * Shared header for VRRPv2/v3 packets.
  31  */
  32 struct vrrp_hdr {
  33         /*
  34          * H  L H  L
  35          * 0000 0000
  36          * ver  type
  37          */
  38         uint8_t vertype;
  39         uint8_t vrid;
  40         uint8_t priority;
  41         uint8_t naddr;
  42         union {
  43                 struct {
  44                         uint8_t auth_type;
  45                         /* advertisement interval (in sec) */
  46                         uint8_t adver_int;
  47                 } v2;
  48                 struct {
  49                         /*
  50                          * advertisement interval (in centiseconds)
  51                          * H  L H          L
  52                          * 0000 000000000000
  53                          * rsvd adver_int
  54                          */
  55                         uint16_t adver_int;
  56                 } v3;
  57         };
  58         uint16_t chksum;
  59 };
  60
  61 struct vrrp_pkt {
  62         struct vrrp_hdr hdr;
  63         union {
  64                 struct in_addr v4;
  65                 struct in6_addr v6;
  66         } addrs[];
  67 } __attribute((packed, aligned(1)));
  68
  69 /*
  70  * Builds a VRRP packet.
  71  *
  72  * pkt
  73  *    Pointer to store pointer to result buffer in
  74  *
  75  * vrid
  76  *    Virtual Router Identifier
  77  *
  78  * prio
  79  *    Virtual Router Priority
  80  *
  81  * max_adver_int
  82  *    time between ADVERTISEMENTs
  83  *
  84  * v6
  85  *    whether 'ips' is an array of v4 or v6 addresses
  86  *
  87  * numip
  88  *    number of IPvX addresses in 'ips'
  89  *
  90  * ips
  91  *    array of pointer to either struct in_addr (v6 = false) or struct in6_addr
  92  *    (v6 = true)
  93  */
  94 ssize_t vrrp_pkt_build(struct vrrp_pkt **pkt, uint8_t vrid, uint8_t prio,
  95                        uint16_t max_adver_int, uint8_t numip,
  96                        struct ipaddr **ips);