diff options
Diffstat (limited to 'src/libsystemd-dhcp/dhcp-option.c')
| -rw-r--r-- | src/libsystemd-dhcp/dhcp-option.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/src/libsystemd-dhcp/dhcp-option.c b/src/libsystemd-dhcp/dhcp-option.c new file mode 100644 index 0000000000..4d45b3b3a4 --- /dev/null +++ b/src/libsystemd-dhcp/dhcp-option.c @@ -0,0 +1,184 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright (C) 2013 Intel Corporation. All rights reserved. + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <stdint.h> +#include <string.h> +#include <errno.h> +#include <stdio.h> + +#include "dhcp-internal.h" + +int dhcp_option_append(uint8_t **buf, size_t *buflen, uint8_t code, + size_t optlen, const void *optval) +{ + if (!buf || !buflen) + return -EINVAL; + + switch (code) { + + case DHCP_OPTION_PAD: + case DHCP_OPTION_END: + if (*buflen < 1) + return -ENOBUFS; + + (*buf)[0] = code; + *buf += 1; + *buflen -= 1; + break; + + default: + if (*buflen < optlen + 2) + return -ENOBUFS; + + if (!optval) + return -EINVAL; + + (*buf)[0] = code; + (*buf)[1] = optlen; + memcpy(&(*buf)[2], optval, optlen); + + *buf += optlen + 2; + *buflen -= (optlen + 2); + + break; + } + + return 0; +} + +static int parse_options(const uint8_t *buf, size_t buflen, uint8_t *overload, + uint8_t *message_type, dhcp_option_cb_t cb, + void *user_data) +{ + const uint8_t *code = buf; + const uint8_t *len; + + while (buflen > 0) { + switch (*code) { + case DHCP_OPTION_PAD: + buflen -= 1; + code++; + break; + + case DHCP_OPTION_END: + return 0; + + case DHCP_OPTION_MESSAGE_TYPE: + if (buflen < 3) + return -ENOBUFS; + buflen -= 3; + + len = code + 1; + if (*len != 1) + return -EINVAL; + + if (message_type) + *message_type = *(len + 1); + + code += 3; + + break; + + case DHCP_OPTION_OVERLOAD: + if (buflen < 3) + return -ENOBUFS; + buflen -= 3; + + len = code + 1; + if (*len != 1) + return -EINVAL; + + if (overload) + *overload = *(len + 1); + + code += 3; + + break; + + default: + if (buflen < 3) + return -ENOBUFS; + + len = code + 1; + + if (buflen < (size_t)*len + 2) + return -EINVAL; + buflen -= *len + 2; + + if (cb) + cb(*code, *len, len + 1, user_data); + + code += *len + 2; + + break; + } + } + + if (buflen) + return -EINVAL; + + return 0; +} + +int dhcp_option_parse(DHCPMessage *message, size_t len, + dhcp_option_cb_t cb, void *user_data) +{ + uint8_t overload = 0; + uint8_t message_type = 0; + uint8_t *opt = (uint8_t *)(message + 1); + int res; + + if (!message) + return -EINVAL; + + if (len < sizeof(DHCPMessage) + 4) + return -EINVAL; + + len -= sizeof(DHCPMessage) + 4; + + if (opt[0] != 0x63 && opt[1] != 0x82 && opt[2] != 0x53 && + opt[3] != 0x63) + return -EINVAL; + + res = parse_options(&opt[4], len, &overload, &message_type, + cb, user_data); + if (res < 0) + return res; + + if (overload & DHCP_OVERLOAD_FILE) { + res = parse_options(message->file, sizeof(message->file), + NULL, &message_type, cb, user_data); + if (res < 0) + return res; + } + + if (overload & DHCP_OVERLOAD_SNAME) { + res = parse_options(message->sname, sizeof(message->sname), + NULL, &message_type, cb, user_data); + if (res < 0) + return res; + } + + if (message_type) + return message_type; + + return -ENOMSG; +} |