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-rw-r--r--src/libsystemd-network/dhcp-option.c438
1 files changed, 438 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..7f49da7
--- /dev/null
+++ b/src/libsystemd-network/dhcp-option.c
@@ -0,0 +1,438 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+ Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include "alloc-util.h"
+#include "dhcp-internal.h"
+#include "dhcp-server-internal.h"
+#include "memory-util.h"
+#include "strv.h"
+#include "utf8.h"
+
+/* Append type-length value structure to the options buffer */
+static int dhcp_option_append_tlv(uint8_t options[], size_t size, size_t *offset, uint8_t code, size_t optlen, const void *optval) {
+ assert(options);
+ assert(size > 0);
+ assert(offset);
+ assert(optlen <= UINT8_MAX);
+ assert(*offset < size);
+
+ if (*offset + 2 + optlen > size)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ options[*offset + 1] = optlen;
+
+ memcpy_safe(&options[*offset + 2], optval, optlen);
+ *offset += 2 + optlen;
+ return 0;
+}
+
+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(size > 0);
+ assert(offset);
+
+ int r;
+
+ 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 (*offset + 1 > size)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ *offset += 1;
+ break;
+
+ case SD_DHCP_OPTION_USER_CLASS: {
+ size_t total = 0;
+
+ if (strv_isempty((char **) optval))
+ return -EINVAL;
+
+ STRV_FOREACH(s, (const char* const*) optval) {
+ size_t len = strlen(*s);
+
+ if (len > 255 || len == 0)
+ return -EINVAL;
+
+ total += 1 + len;
+ }
+
+ if (*offset + 2 + total > size)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ options[*offset + 1] = total;
+ *offset += 2;
+
+ STRV_FOREACH(s, (const char* const*) optval) {
+ size_t len = strlen(*s);
+
+ options[*offset] = len;
+ memcpy(&options[*offset + 1], *s, len);
+ *offset += 1 + len;
+ }
+
+ break;
+ }
+ case SD_DHCP_OPTION_SIP_SERVER:
+ if (*offset + 3 + optlen > size)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ options[*offset + 1] = optlen + 1;
+ options[*offset + 2] = 1;
+
+ memcpy_safe(&options[*offset + 3], optval, optlen);
+ *offset += 3 + optlen;
+
+ break;
+ case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
+ OrderedSet *s = (OrderedSet *) optval;
+ struct sd_dhcp_option *p;
+ size_t l = 0;
+
+ ORDERED_SET_FOREACH(p, s)
+ l += p->length + 2;
+
+ if (*offset + l + 2 > size)
+ return -ENOBUFS;
+
+ options[*offset] = code;
+ options[*offset + 1] = l;
+ *offset += 2;
+
+ ORDERED_SET_FOREACH(p, s) {
+ r = dhcp_option_append_tlv(options, size, offset, p->option, p->length, p->data);
+ if (r < 0)
+ return r;
+ }
+ break;
+ }
+ case SD_DHCP_OPTION_RELAY_AGENT_INFORMATION: {
+ sd_dhcp_server *server = (sd_dhcp_server *) optval;
+ size_t current_offset = *offset + 2;
+
+ if (server->agent_circuit_id) {
+ r = dhcp_option_append_tlv(options, size, &current_offset, SD_DHCP_RELAY_AGENT_CIRCUIT_ID,
+ strlen(server->agent_circuit_id), server->agent_circuit_id);
+ if (r < 0)
+ return r;
+ }
+ if (server->agent_remote_id) {
+ r = dhcp_option_append_tlv(options, size, &current_offset, SD_DHCP_RELAY_AGENT_REMOTE_ID,
+ strlen(server->agent_remote_id), server->agent_remote_id);
+ if (r < 0)
+ return r;
+ }
+
+ options[*offset] = code;
+ options[*offset + 1] = current_offset - *offset - 2;
+ assert(current_offset - *offset - 2 <= UINT8_MAX);
+ *offset = current_offset;
+ break;
+ }
+ default:
+ return dhcp_option_append_tlv(options, size, offset, code, optlen, optval);
+ }
+ return 0;
+}
+
+static int option_length(uint8_t *options, size_t length, size_t offset) {
+ assert(options);
+ assert(offset < length);
+
+ if (IN_SET(options[offset], SD_DHCP_OPTION_PAD, SD_DHCP_OPTION_END))
+ return 1;
+ if (length < offset + 2)
+ return -ENOBUFS;
+
+ /* validating that buffer is long enough */
+ if (length < offset + 2 + options[offset + 1])
+ return -ENOBUFS;
+
+ return options[offset + 1] + 2;
+}
+
+int dhcp_option_find_option(uint8_t *options, size_t length, uint8_t code, size_t *ret_offset) {
+ int r;
+
+ assert(options);
+ assert(ret_offset);
+
+ for (size_t offset = 0; offset < length; offset += r) {
+ r = option_length(options, length, offset);
+ if (r < 0)
+ return r;
+
+ if (code == options[offset]) {
+ *ret_offset = offset;
+ return r;
+ }
+ }
+ return -ENOENT;
+}
+
+int dhcp_option_remove_option(uint8_t *options, size_t length, uint8_t option_code) {
+ int r;
+ size_t offset;
+
+ assert(options);
+
+ r = dhcp_option_find_option(options, length, option_code, &offset);
+ if (r < 0)
+ return r;
+
+ memmove(options + offset, options + offset + r, length - offset - r);
+ return length - r;
+}
+
+int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset,
+ uint8_t overload,
+ uint8_t code, size_t optlen, const void *optval) {
+ const bool use_file = overload & DHCP_OVERLOAD_FILE;
+ const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
+ int r;
+
+ assert(message);
+ assert(offset);
+
+ /* If *offset is in range [0, size), we are writing to ->options,
+ * if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
+ * if *offset is in range [size + use_file*sizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
+ * and use_sname, we are writing to ->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 && (use_file || use_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 (use_file) {
+ size_t 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 && use_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->file, sizeof(message->file), &file_offset, SD_DHCP_OPTION_END, 0, NULL);
+ if (r < 0)
+ return r;
+
+ *offset = size + sizeof(message->file);
+ } else
+ return r;
+ }
+ }
+
+ if (use_sname) {
+ size_t sname_offset = *offset - size - use_file*sizeof(message->file);
+
+ 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 + use_file*sizeof(message->file) + 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 = memdup_suffix0((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;
+}
+
+static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
+ if (!i)
+ return NULL;
+
+ free(i->data);
+ return mfree(i);
+}
+
+int sd_dhcp_option_new(uint8_t option, const void *data, size_t length, sd_dhcp_option **ret) {
+ assert_return(ret, -EINVAL);
+ assert_return(length == 0 || data, -EINVAL);
+
+ _cleanup_free_ void *q = memdup(data, length);
+ if (!q)
+ return -ENOMEM;
+
+ sd_dhcp_option *p = new(sd_dhcp_option, 1);
+ if (!p)
+ return -ENOMEM;
+
+ *p = (sd_dhcp_option) {
+ .n_ref = 1,
+ .option = option,
+ .length = length,
+ .data = TAKE_PTR(q),
+ };
+
+ *ret = TAKE_PTR(p);
+ return 0;
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
+DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
+ dhcp_option_hash_ops,
+ void,
+ trivial_hash_func,
+ trivial_compare_func,
+ sd_dhcp_option,
+ sd_dhcp_option_unref);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-18 09:50:38 +0000