src/libsystemd-network/dhcp6-option.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright (C) 2014 Intel Corporation. All rights reserved.
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <netinet/in.h>
  23 #include <errno.h>
  24 #include <string.h>
  25
  26 #include "sparse-endian.h"
  27 #include "util.h"
  28
  29 #include "dhcp6-internal.h"
  30 #include "dhcp6-protocol.h"
  31
  32 #define DHCP6_OPTION_HDR_LEN                    4
  33 #define DHCP6_OPTION_IA_NA_LEN                  12
  34 #define DHCP6_OPTION_IA_TA_LEN                  4
  35 #define DHCP6_OPTION_IAADDR_LEN                 24
  36
  37 static int option_append_hdr(uint8_t **buf, size_t *buflen, uint16_t optcode,
  38                              size_t optlen) {
  39         assert_return(buf, -EINVAL);
  40         assert_return(*buf, -EINVAL);
  41         assert_return(buflen, -EINVAL);
  42
  43         if (optlen > 0xffff || *buflen < optlen + DHCP6_OPTION_HDR_LEN)
  44                 return -ENOBUFS;
  45
  46         (*buf)[0] = optcode >> 8;
  47         (*buf)[1] = optcode & 0xff;
  48         (*buf)[2] = optlen >> 8;
  49         (*buf)[3] = optlen & 0xff;
  50
  51         *buf += DHCP6_OPTION_HDR_LEN;
  52         *buflen -= DHCP6_OPTION_HDR_LEN;
  53
  54         return 0;
  55 }
  56
  57 int dhcp6_option_append(uint8_t **buf, size_t *buflen, uint16_t code,
  58                         size_t optlen, const void *optval) {
  59         int r;
  60
  61         assert_return(optval, -EINVAL);
  62
  63         r = option_append_hdr(buf, buflen, code, optlen);
  64         if (r < 0)
  65                 return r;
  66
  67         memcpy(*buf, optval, optlen);
  68
  69         *buf += optlen;
  70         *buflen -= optlen;
  71
  72         return 0;
  73 }
  74
  75 int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, DHCP6IA *ia) {
  76         uint16_t len;
  77         uint8_t *ia_hdr;
  78         size_t ia_buflen, ia_addrlen = 0;
  79         DHCP6Address *addr;
  80         int r;
  81
  82         assert_return(buf && *buf && buflen && ia, -EINVAL);
  83
  84         switch (ia->type) {
  85         case DHCP6_OPTION_IA_NA:
  86                 len = DHCP6_OPTION_IA_NA_LEN;
  87                 break;
  88
  89         case DHCP6_OPTION_IA_TA:
  90                 len = DHCP6_OPTION_IA_TA_LEN;
  91                 break;
  92
  93         default:
  94                 return -EINVAL;
  95         }
  96
  97         if (*buflen < len)
  98                 return -ENOBUFS;
  99
 100         ia_hdr = *buf;
 101         ia_buflen = *buflen;
 102
 103         *buf += DHCP6_OPTION_HDR_LEN;
 104         *buflen -= DHCP6_OPTION_HDR_LEN;
 105
 106         memcpy(*buf, &ia->id, len);
 107
 108         *buf += len;
 109         *buflen -= len;
 110
 111         LIST_FOREACH(addresses, addr, ia->addresses) {
 112                 r = option_append_hdr(buf, buflen, DHCP6_OPTION_IAADDR,
 113                                       DHCP6_OPTION_IAADDR_LEN);
 114                 if (r < 0)
 115                         return r;
 116
 117                 memcpy(*buf, &addr->address, DHCP6_OPTION_IAADDR_LEN);
 118
 119                 *buf += DHCP6_OPTION_IAADDR_LEN;
 120                 *buflen -= DHCP6_OPTION_IAADDR_LEN;
 121
 122                 ia_addrlen += DHCP6_OPTION_HDR_LEN + DHCP6_OPTION_IAADDR_LEN;
 123         }
 124
 125         r = option_append_hdr(&ia_hdr, &ia_buflen, ia->type, len + ia_addrlen);
 126         if (r < 0)
 127                 return r;
 128
 129         return 0;
 130 }
 131
 132 int dhcp6_option_parse(uint8_t **buf, size_t *buflen, uint16_t *optcode,
 133                        size_t *optlen, uint8_t **optvalue) {
 134         assert_return(buf && buflen && optcode && optlen && optvalue, -EINVAL);
 135
 136         if (*buflen == 0)
 137                 return -ENOMSG;
 138
 139         *optcode = (*buf)[0] << 8 | (*buf)[1];
 140         *optlen = (*buf)[2] << 8 | (*buf)[3];
 141
 142         if (*optlen > *buflen - 4)
 143                 return -ENOBUFS;
 144
 145         *optvalue = &(*buf)[4];
 146         *buflen -= (*optlen + 4);
 147         (*buf) += (*optlen + 4);
 148
 149         return 0;
 150 }