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-rw-r--r--src/libsystemd-network/dhcp-option.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c
new file mode 100644
index 0000000..ad3f925
--- /dev/null
+++ b/src/libsystemd-network/dhcp-option.c
@@ -0,0 +1,274 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/***
+ Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "alloc-util.h"
+#include "utf8.h"
+#include "strv.h"
+
+#include "dhcp-internal.h"
+
+static int option_append(uint8_t options[], size_t size, size_t *offset,
+ uint8_t code, size_t optlen, const void *optval) {
+ assert(options);
+ assert(offset);
+
+ if (code != SD_DHCP_OPTION_END)
+ /* always make sure there is space for an END option */
+ size--;
+
+ switch (code) {
+
+ case SD_DHCP_OPTION_PAD:
+ case SD_DHCP_OPTION_END:
+ if (size < *offset + 1)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ *offset += 1;
+ break;
+
+ case SD_DHCP_OPTION_USER_CLASS: {
+ size_t len = 0;
+ char **s;
+
+ STRV_FOREACH(s, (char **) optval)
+ len += strlen(*s) + 1;
+
+ if (size < *offset + len + 2)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ options[*offset + 1] = len;
+ *offset += 2;
+
+ STRV_FOREACH(s, (char **) optval) {
+ len = strlen(*s);
+
+ if (len > 255)
+ return -ENAMETOOLONG;
+
+ options[*offset] = len;
+
+ memcpy_safe(&options[*offset + 1], *s, len);
+ *offset += len + 1;
+ }
+
+ break;
+ }
+ default:
+ if (size < *offset + optlen + 2)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ options[*offset + 1] = optlen;
+
+ memcpy_safe(&options[*offset + 2], optval, optlen);
+ *offset += optlen + 2;
+
+ break;
+ }
+
+ return 0;
+}
+
+int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset,
+ uint8_t overload,
+ uint8_t code, size_t optlen, const void *optval) {
+ size_t file_offset = 0, sname_offset =0;
+ bool file, sname;
+ int r;
+
+ assert(message);
+ assert(offset);
+
+ file = overload & DHCP_OVERLOAD_FILE;
+ sname = overload & DHCP_OVERLOAD_SNAME;
+
+ if (*offset < size) {
+ /* still space in the options array */
+ r = option_append(message->options, size, offset, code, optlen, optval);
+ if (r >= 0)
+ return 0;
+ else if (r == -ENOBUFS && (file || sname)) {
+ /* did not fit, but we have more buffers to try
+ close the options array and move the offset to its end */
+ r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
+ if (r < 0)
+ return r;
+
+ *offset = size;
+ } else
+ return r;
+ }
+
+ if (overload & DHCP_OVERLOAD_FILE) {
+ file_offset = *offset - size;
+
+ if (file_offset < sizeof(message->file)) {
+ /* still space in the 'file' array */
+ r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
+ if (r >= 0) {
+ *offset = size + file_offset;
+ return 0;
+ } else if (r == -ENOBUFS && sname) {
+ /* did not fit, but we have more buffers to try
+ close the file array and move the offset to its end */
+ r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
+ if (r < 0)
+ return r;
+
+ *offset = size + sizeof(message->file);
+ } else
+ return r;
+ }
+ }
+
+ if (overload & DHCP_OVERLOAD_SNAME) {
+ sname_offset = *offset - size - (file ? sizeof(message->file) : 0);
+
+ if (sname_offset < sizeof(message->sname)) {
+ /* still space in the 'sname' array */
+ r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
+ if (r >= 0) {
+ *offset = size + (file ? sizeof(message->file) : 0) + sname_offset;
+ return 0;
+ } else {
+ /* no space, or other error, give up */
+ return r;
+ }
+ }
+ }
+
+ return -ENOBUFS;
+}
+
+static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
+ uint8_t *message_type, char **error_message, dhcp_option_callback_t cb,
+ void *userdata) {
+ uint8_t code, len;
+ const uint8_t *option;
+ size_t offset = 0;
+
+ while (offset < buflen) {
+ code = options[offset ++];
+
+ switch (code) {
+ case SD_DHCP_OPTION_PAD:
+ continue;
+
+ case SD_DHCP_OPTION_END:
+ return 0;
+ }
+
+ if (buflen < offset + 1)
+ return -ENOBUFS;
+
+ len = options[offset ++];
+
+ if (buflen < offset + len)
+ return -EINVAL;
+
+ option = &options[offset];
+
+ switch (code) {
+ case SD_DHCP_OPTION_MESSAGE_TYPE:
+ if (len != 1)
+ return -EINVAL;
+
+ if (message_type)
+ *message_type = *option;
+
+ break;
+
+ case SD_DHCP_OPTION_ERROR_MESSAGE:
+ if (len == 0)
+ return -EINVAL;
+
+ if (error_message) {
+ _cleanup_free_ char *string = NULL;
+
+ /* Accept a trailing NUL byte */
+ if (memchr(option, 0, len - 1))
+ return -EINVAL;
+
+ string = strndup((const char *) option, len);
+ if (!string)
+ return -ENOMEM;
+
+ if (!ascii_is_valid(string))
+ return -EINVAL;
+
+ free_and_replace(*error_message, string);
+ }
+
+ break;
+ case SD_DHCP_OPTION_OVERLOAD:
+ if (len != 1)
+ return -EINVAL;
+
+ if (overload)
+ *overload = *option;
+
+ break;
+
+ default:
+ if (cb)
+ cb(code, len, option, userdata);
+
+ break;
+ }
+
+ offset += len;
+ }
+
+ if (offset < buflen)
+ return -EINVAL;
+
+ return 0;
+}
+
+int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t cb, void *userdata, char **_error_message) {
+ _cleanup_free_ char *error_message = NULL;
+ uint8_t overload = 0;
+ uint8_t message_type = 0;
+ int r;
+
+ if (!message)
+ return -EINVAL;
+
+ if (len < sizeof(DHCPMessage))
+ return -EINVAL;
+
+ len -= sizeof(DHCPMessage);
+
+ r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
+ if (r < 0)
+ return r;
+
+ if (overload & DHCP_OVERLOAD_FILE) {
+ r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
+ if (r < 0)
+ return r;
+ }
+
+ if (overload & DHCP_OVERLOAD_SNAME) {
+ r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
+ if (r < 0)
+ return r;
+ }
+
+ if (message_type == 0)
+ return -ENOMSG;
+
+ if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
+ *_error_message = TAKE_PTR(error_message);
+
+ return message_type;
+}
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