627 lines
19 KiB
C
627 lines
19 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/***
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This file is part of systemd.
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Copyright (C) 2014-2015 Intel Corporation. All rights reserved.
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <netinet/in.h>
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#include <string.h>
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#include "sd-dhcp6-client.h"
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#include "alloc-util.h"
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#include "dhcp6-internal.h"
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#include "dhcp6-lease-internal.h"
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#include "dhcp6-protocol.h"
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#include "dns-domain.h"
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#include "sparse-endian.h"
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#include "strv.h"
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#include "unaligned.h"
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#include "util.h"
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typedef struct DHCP6StatusOption {
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struct DHCP6Option option;
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be16_t status;
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char msg[];
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} _packed_ DHCP6StatusOption;
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typedef struct DHCP6AddressOption {
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struct DHCP6Option option;
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struct iaaddr iaaddr;
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uint8_t options[];
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} _packed_ DHCP6AddressOption;
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typedef struct DHCP6PDPrefixOption {
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struct DHCP6Option option;
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struct iapdprefix iapdprefix;
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uint8_t options[];
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} _packed_ DHCP6PDPrefixOption;
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#define DHCP6_OPTION_IA_NA_LEN (sizeof(struct ia_na))
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#define DHCP6_OPTION_IA_PD_LEN (sizeof(struct ia_pd))
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#define DHCP6_OPTION_IA_TA_LEN (sizeof(struct ia_ta))
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static int option_append_hdr(uint8_t **buf, size_t *buflen, uint16_t optcode,
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size_t optlen) {
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DHCP6Option *option = (DHCP6Option*) *buf;
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assert_return(buf, -EINVAL);
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assert_return(*buf, -EINVAL);
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assert_return(buflen, -EINVAL);
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if (optlen > 0xffff || *buflen < optlen + sizeof(DHCP6Option))
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return -ENOBUFS;
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option->code = htobe16(optcode);
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option->len = htobe16(optlen);
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*buf += sizeof(DHCP6Option);
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*buflen -= sizeof(DHCP6Option);
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return 0;
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}
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int dhcp6_option_append(uint8_t **buf, size_t *buflen, uint16_t code,
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size_t optlen, const void *optval) {
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int r;
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assert_return(optval || optlen == 0, -EINVAL);
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r = option_append_hdr(buf, buflen, code, optlen);
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if (r < 0)
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return r;
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memcpy_safe(*buf, optval, optlen);
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*buf += optlen;
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*buflen -= optlen;
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return 0;
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}
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int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, DHCP6IA *ia) {
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uint16_t len;
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uint8_t *ia_hdr;
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size_t iaid_offset, ia_buflen, ia_addrlen = 0;
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DHCP6Address *addr;
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int r;
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assert_return(buf && *buf && buflen && ia, -EINVAL);
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switch (ia->type) {
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case SD_DHCP6_OPTION_IA_NA:
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len = DHCP6_OPTION_IA_NA_LEN;
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iaid_offset = offsetof(DHCP6IA, ia_na);
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break;
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case SD_DHCP6_OPTION_IA_TA:
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len = DHCP6_OPTION_IA_TA_LEN;
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iaid_offset = offsetof(DHCP6IA, ia_ta);
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break;
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default:
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return -EINVAL;
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}
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if (*buflen < len)
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return -ENOBUFS;
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ia_hdr = *buf;
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ia_buflen = *buflen;
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*buf += sizeof(DHCP6Option);
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*buflen -= sizeof(DHCP6Option);
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memcpy(*buf, (char*) ia + iaid_offset, len);
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*buf += len;
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*buflen -= len;
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LIST_FOREACH(addresses, addr, ia->addresses) {
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r = option_append_hdr(buf, buflen, SD_DHCP6_OPTION_IAADDR,
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sizeof(addr->iaaddr));
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if (r < 0)
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return r;
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memcpy(*buf, &addr->iaaddr, sizeof(addr->iaaddr));
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*buf += sizeof(addr->iaaddr);
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*buflen -= sizeof(addr->iaaddr);
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ia_addrlen += sizeof(DHCP6Option) + sizeof(addr->iaaddr);
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}
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r = option_append_hdr(&ia_hdr, &ia_buflen, ia->type, len + ia_addrlen);
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if (r < 0)
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return r;
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return 0;
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}
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int dhcp6_option_append_fqdn(uint8_t **buf, size_t *buflen, const char *fqdn) {
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uint8_t buffer[1 + DNS_WIRE_FOMAT_HOSTNAME_MAX];
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int r;
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assert_return(buf && *buf && buflen && fqdn, -EINVAL);
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buffer[0] = DHCP6_FQDN_FLAG_S; /* Request server to perform AAAA RR DNS updates */
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/* Store domain name after flags field */
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r = dns_name_to_wire_format(fqdn, buffer + 1, sizeof(buffer) - 1, false);
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if (r <= 0)
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return r;
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/*
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* According to RFC 4704, chapter 4.2 only add terminating zero-length
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* label in case a FQDN is provided. Since dns_name_to_wire_format
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* always adds terminating zero-length label remove if only a hostname
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* is provided.
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*/
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if (dns_name_is_single_label(fqdn))
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r--;
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r = dhcp6_option_append(buf, buflen, SD_DHCP6_OPTION_FQDN, 1 + r, buffer);
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return r;
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}
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int dhcp6_option_append_pd(uint8_t *buf, size_t len, DHCP6IA *pd) {
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DHCP6Option *option = (DHCP6Option *)buf;
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size_t i = sizeof(*option) + sizeof(pd->ia_pd);
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DHCP6Address *prefix;
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assert_return(buf, -EINVAL);
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assert_return(pd, -EINVAL);
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assert_return(pd->type == SD_DHCP6_OPTION_IA_PD, -EINVAL);
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if (len < i)
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return -ENOBUFS;
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option->code = htobe16(SD_DHCP6_OPTION_IA_PD);
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memcpy(&option->data, &pd->ia_pd, sizeof(pd->ia_pd));
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LIST_FOREACH(addresses, prefix, pd->addresses) {
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DHCP6PDPrefixOption *prefix_opt;
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if (len < i + sizeof(*prefix_opt))
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return -ENOBUFS;
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prefix_opt = (DHCP6PDPrefixOption *)&buf[i];
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prefix_opt->option.code = htobe16(SD_DHCP6_OPTION_IA_PD_PREFIX);
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prefix_opt->option.len = htobe16(sizeof(prefix_opt->iapdprefix));
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memcpy(&prefix_opt->iapdprefix, &prefix->iapdprefix,
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sizeof(struct iapdprefix));
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i += sizeof(*prefix_opt);
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}
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option->len = htobe16(i - sizeof(*option));
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return i;
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}
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static int option_parse_hdr(uint8_t **buf, size_t *buflen, uint16_t *optcode, size_t *optlen) {
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DHCP6Option *option = (DHCP6Option*) *buf;
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uint16_t len;
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assert_return(buf, -EINVAL);
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assert_return(optcode, -EINVAL);
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assert_return(optlen, -EINVAL);
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if (*buflen < sizeof(DHCP6Option))
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return -ENOMSG;
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len = be16toh(option->len);
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if (len > *buflen)
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return -ENOMSG;
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*optcode = be16toh(option->code);
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*optlen = len;
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*buf += 4;
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*buflen -= 4;
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return 0;
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}
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int dhcp6_option_parse(uint8_t **buf, size_t *buflen, uint16_t *optcode,
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size_t *optlen, uint8_t **optvalue) {
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int r;
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assert_return(buf && buflen && optcode && optlen && optvalue, -EINVAL);
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r = option_parse_hdr(buf, buflen, optcode, optlen);
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if (r < 0)
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return r;
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if (*optlen > *buflen)
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return -ENOBUFS;
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*optvalue = *buf;
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*buflen -= *optlen;
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*buf += *optlen;
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return 0;
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}
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int dhcp6_option_parse_status(DHCP6Option *option) {
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DHCP6StatusOption *statusopt = (DHCP6StatusOption *)option;
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if (be16toh(option->len) + sizeof(DHCP6Option) < sizeof(*statusopt))
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return -ENOBUFS;
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return be16toh(statusopt->status);
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}
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static int dhcp6_option_parse_address(DHCP6Option *option, DHCP6IA *ia,
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uint32_t *lifetime_valid) {
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DHCP6AddressOption *addr_option = (DHCP6AddressOption *)option;
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DHCP6Address *addr;
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uint32_t lt_valid, lt_pref;
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int r;
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if (be16toh(option->len) + sizeof(DHCP6Option) < sizeof(*addr_option))
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return -ENOBUFS;
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lt_valid = be32toh(addr_option->iaaddr.lifetime_valid);
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lt_pref = be32toh(addr_option->iaaddr.lifetime_preferred);
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if (lt_valid == 0 || lt_pref > lt_valid) {
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log_dhcp6_client(client, "Valid lifetime of an IA address is zero or preferred lifetime %d > valid lifetime %d",
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lt_pref, lt_valid);
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return 0;
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}
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if (be16toh(option->len) + sizeof(DHCP6Option) > sizeof(*addr_option)) {
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r = dhcp6_option_parse_status((DHCP6Option *)addr_option->options);
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if (r != 0)
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return r < 0 ? r: 0;
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}
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addr = new0(DHCP6Address, 1);
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if (!addr)
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return -ENOMEM;
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LIST_INIT(addresses, addr);
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memcpy(&addr->iaaddr, option->data, sizeof(addr->iaaddr));
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LIST_PREPEND(addresses, ia->addresses, addr);
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*lifetime_valid = be32toh(addr->iaaddr.lifetime_valid);
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return 0;
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}
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static int dhcp6_option_parse_pdprefix(DHCP6Option *option, DHCP6IA *ia,
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uint32_t *lifetime_valid) {
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DHCP6PDPrefixOption *pdprefix_option = (DHCP6PDPrefixOption *)option;
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DHCP6Address *prefix;
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uint32_t lt_valid, lt_pref;
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int r;
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if (be16toh(option->len) + sizeof(DHCP6Option) < sizeof(*pdprefix_option))
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return -ENOBUFS;
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lt_valid = be32toh(pdprefix_option->iapdprefix.lifetime_valid);
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lt_pref = be32toh(pdprefix_option->iapdprefix.lifetime_preferred);
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if (lt_valid == 0 || lt_pref > lt_valid) {
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log_dhcp6_client(client, "Valid lifetieme of a PD prefix is zero or preferred lifetime %d > valid lifetime %d",
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lt_pref, lt_valid);
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return 0;
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}
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if (be16toh(option->len) + sizeof(DHCP6Option) > sizeof(*pdprefix_option)) {
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r = dhcp6_option_parse_status((DHCP6Option *)pdprefix_option->options);
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if (r != 0)
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return r < 0 ? r: 0;
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}
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prefix = new0(DHCP6Address, 1);
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if (!prefix)
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return -ENOMEM;
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LIST_INIT(addresses, prefix);
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memcpy(&prefix->iapdprefix, option->data, sizeof(prefix->iapdprefix));
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LIST_PREPEND(addresses, ia->addresses, prefix);
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*lifetime_valid = be32toh(prefix->iapdprefix.lifetime_valid);
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return 0;
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}
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int dhcp6_option_parse_ia(DHCP6Option *iaoption, DHCP6IA *ia) {
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uint16_t iatype, optlen;
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size_t i, len;
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int r = 0, status;
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uint16_t opt;
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size_t iaaddr_offset;
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uint32_t lt_t1, lt_t2, lt_valid = 0, lt_min = UINT32_MAX;
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assert_return(ia, -EINVAL);
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assert_return(!ia->addresses, -EINVAL);
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iatype = be16toh(iaoption->code);
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len = be16toh(iaoption->len);
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switch (iatype) {
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case SD_DHCP6_OPTION_IA_NA:
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if (len < DHCP6_OPTION_IA_NA_LEN) {
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r = -ENOBUFS;
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goto error;
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}
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iaaddr_offset = DHCP6_OPTION_IA_NA_LEN;
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memcpy(&ia->ia_na, iaoption->data, sizeof(ia->ia_na));
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lt_t1 = be32toh(ia->ia_na.lifetime_t1);
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lt_t2 = be32toh(ia->ia_na.lifetime_t2);
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if (lt_t1 && lt_t2 && lt_t1 > lt_t2) {
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log_dhcp6_client(client, "IA NA T1 %ds > T2 %ds",
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lt_t1, lt_t2);
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r = -EINVAL;
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goto error;
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}
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break;
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case SD_DHCP6_OPTION_IA_PD:
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if (len < sizeof(ia->ia_pd)) {
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r = -ENOBUFS;
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goto error;
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}
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iaaddr_offset = sizeof(ia->ia_pd);
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memcpy(&ia->ia_pd, iaoption->data, sizeof(ia->ia_pd));
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lt_t1 = be32toh(ia->ia_pd.lifetime_t1);
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lt_t2 = be32toh(ia->ia_pd.lifetime_t2);
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if (lt_t1 && lt_t2 && lt_t1 > lt_t2) {
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log_dhcp6_client(client, "IA PD T1 %ds > T2 %ds",
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lt_t1, lt_t2);
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r = -EINVAL;
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goto error;
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}
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break;
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case SD_DHCP6_OPTION_IA_TA:
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if (len < DHCP6_OPTION_IA_TA_LEN) {
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r = -ENOBUFS;
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goto error;
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}
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iaaddr_offset = DHCP6_OPTION_IA_TA_LEN;
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memcpy(&ia->ia_ta.id, iaoption->data, sizeof(ia->ia_ta));
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break;
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default:
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r = -ENOMSG;
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goto error;
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}
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ia->type = iatype;
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i = iaaddr_offset;
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while (i < len) {
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DHCP6Option *option = (DHCP6Option *)&iaoption->data[i];
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if (len < i + sizeof(*option) || len < i + sizeof(*option) + be16toh(option->len)) {
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r = -ENOBUFS;
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goto error;
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}
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opt = be16toh(option->code);
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optlen = be16toh(option->len);
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switch (opt) {
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case SD_DHCP6_OPTION_IAADDR:
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if (!IN_SET(ia->type, SD_DHCP6_OPTION_IA_NA, SD_DHCP6_OPTION_IA_TA)) {
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log_dhcp6_client(client, "IA Address option not in IA NA or TA option");
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r = -EINVAL;
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goto error;
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}
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r = dhcp6_option_parse_address(option, ia, <_valid);
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if (r < 0)
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goto error;
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if (lt_valid < lt_min)
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lt_min = lt_valid;
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break;
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case SD_DHCP6_OPTION_IA_PD_PREFIX:
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if (!IN_SET(ia->type, SD_DHCP6_OPTION_IA_PD)) {
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log_dhcp6_client(client, "IA PD Prefix option not in IA PD option");
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r = -EINVAL;
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goto error;
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}
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r = dhcp6_option_parse_pdprefix(option, ia, <_valid);
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if (r < 0)
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goto error;
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if (lt_valid < lt_min)
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lt_min = lt_valid;
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break;
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case SD_DHCP6_OPTION_STATUS_CODE:
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status = dhcp6_option_parse_status(option);
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if (status) {
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log_dhcp6_client(client, "IA status %d",
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status);
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dhcp6_lease_free_ia(ia);
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r = -EINVAL;
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goto error;
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}
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break;
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default:
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log_dhcp6_client(client, "Unknown IA option %d", opt);
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break;
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}
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i += sizeof(*option) + optlen;
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}
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switch(iatype) {
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case SD_DHCP6_OPTION_IA_NA:
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if (!ia->ia_na.lifetime_t1 && !ia->ia_na.lifetime_t2) {
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lt_t1 = lt_min / 2;
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lt_t2 = lt_min / 10 * 8;
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ia->ia_na.lifetime_t1 = htobe32(lt_t1);
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ia->ia_na.lifetime_t2 = htobe32(lt_t2);
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log_dhcp6_client(client, "Computed IA NA T1 %ds and T2 %ds as both were zero",
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lt_t1, lt_t2);
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}
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break;
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case SD_DHCP6_OPTION_IA_PD:
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if (!ia->ia_pd.lifetime_t1 && !ia->ia_pd.lifetime_t2) {
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lt_t1 = lt_min / 2;
|
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lt_t2 = lt_min / 10 * 8;
|
|
ia->ia_pd.lifetime_t1 = htobe32(lt_t1);
|
|
ia->ia_pd.lifetime_t2 = htobe32(lt_t2);
|
|
|
|
log_dhcp6_client(client, "Computed IA PD T1 %ds and T2 %ds as both were zero",
|
|
lt_t1, lt_t2);
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
error:
|
|
return r;
|
|
}
|
|
|
|
int dhcp6_option_parse_ip6addrs(uint8_t *optval, uint16_t optlen,
|
|
struct in6_addr **addrs, size_t count,
|
|
size_t *allocated) {
|
|
|
|
if (optlen == 0 || optlen % sizeof(struct in6_addr) != 0)
|
|
return -EINVAL;
|
|
|
|
if (!GREEDY_REALLOC(*addrs, *allocated,
|
|
count * sizeof(struct in6_addr) + optlen))
|
|
return -ENOMEM;
|
|
|
|
memcpy(*addrs + count, optval, optlen);
|
|
|
|
count += optlen / sizeof(struct in6_addr);
|
|
|
|
return count;
|
|
}
|
|
|
|
int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char ***str_arr) {
|
|
size_t pos = 0, idx = 0;
|
|
_cleanup_strv_free_ char **names = NULL;
|
|
int r;
|
|
|
|
assert_return(optlen > 1, -ENODATA);
|
|
assert_return(optval[optlen - 1] == '\0', -EINVAL);
|
|
|
|
while (pos < optlen) {
|
|
_cleanup_free_ char *ret = NULL;
|
|
size_t n = 0, allocated = 0;
|
|
bool first = true;
|
|
|
|
for (;;) {
|
|
uint8_t c;
|
|
|
|
c = optval[pos++];
|
|
|
|
if (c == 0)
|
|
/* End of name */
|
|
break;
|
|
else if (c <= 63) {
|
|
const char *label;
|
|
|
|
/* Literal label */
|
|
label = (const char *)&optval[pos];
|
|
pos += c;
|
|
if (pos > optlen)
|
|
return -EMSGSIZE;
|
|
|
|
if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) {
|
|
r = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
if (first)
|
|
first = false;
|
|
else
|
|
ret[n++] = '.';
|
|
|
|
r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
|
|
if (r < 0)
|
|
goto fail;
|
|
|
|
n += r;
|
|
continue;
|
|
} else {
|
|
r = -EBADMSG;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
if (!GREEDY_REALLOC(ret, allocated, n + 1)) {
|
|
r = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
ret[n] = 0;
|
|
|
|
r = strv_extend(&names, ret);
|
|
if (r < 0)
|
|
goto fail;
|
|
|
|
idx++;
|
|
}
|
|
|
|
*str_arr = TAKE_PTR(names);
|
|
|
|
return idx;
|
|
|
|
fail:
|
|
return r;
|
|
}
|