#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;
+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 != DHCP_OPTION_END)
+ /* always make sure there is space for an END option */
+ size --;
switch (code) {
case DHCP_OPTION_PAD:
case DHCP_OPTION_END:
- if (*buflen < 1)
+ if (size < *offset + 1)
return -ENOBUFS;
- (*buf)[0] = code;
- *buf += 1;
- *buflen -= 1;
+ options[*offset] = code;
+ *offset += 1;
break;
default:
- if (*buflen < optlen + 2)
+ if (size < *offset + optlen + 2)
return -ENOBUFS;
- if (!optval)
- return -EINVAL;
+ options[*offset] = code;
+ options[*offset + 1] = optlen;
+
+ if (optlen) {
+ assert(optval);
- (*buf)[0] = code;
- (*buf)[1] = optlen;
- memcpy(&(*buf)[2], optval, optlen);
+ memcpy(&options[*offset + 2], optval, optlen);
+ }
- *buf += optlen + 2;
- *buflen -= (optlen + 2);
+ *offset += optlen + 2;
break;
}
return 0;
}
-static int parse_options(const uint8_t *buf, size_t buflen, uint8_t *overload,
+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, 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, 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, dhcp_option_cb_t cb,
- void *user_data)
-{
- const uint8_t *code = buf;
- const uint8_t *len;
+ void *user_data) {
+ uint8_t code, len;
+ size_t offset = 0;
- while (buflen > 0) {
- switch (*code) {
+ while (offset < buflen) {
+ switch (options[offset]) {
case DHCP_OPTION_PAD:
- buflen -= 1;
- code++;
+ offset++;
+
break;
case DHCP_OPTION_END:
return 0;
case DHCP_OPTION_MESSAGE_TYPE:
- if (buflen < 3)
+ if (buflen < offset + 3)
return -ENOBUFS;
- buflen -= 3;
- len = code + 1;
- if (*len != 1)
+ len = options[++offset];
+ if (len != 1)
return -EINVAL;
if (message_type)
- *message_type = *(len + 1);
+ *message_type = options[++offset];
+ else
+ offset++;
- code += 3;
+ offset++;
break;
case DHCP_OPTION_OVERLOAD:
- if (buflen < 3)
+ if (buflen < offset + 3)
return -ENOBUFS;
- buflen -= 3;
- len = code + 1;
- if (*len != 1)
+ len = options[++offset];
+ if (len != 1)
return -EINVAL;
if (overload)
- *overload = *(len + 1);
+ *overload = options[++offset];
+ else
+ offset++;
- code += 3;
+ offset++;
break;
default:
- if (buflen < 3)
+ if (buflen < offset + 3)
return -ENOBUFS;
- len = code + 1;
+ code = options[offset];
+ len = options[++offset];
- if (buflen < (size_t)*len + 2)
+ if (buflen < ++offset + len)
return -EINVAL;
- buflen -= *len + 2;
if (cb)
- cb(*code, *len, len + 1, user_data);
+ cb(code, len, &options[offset], user_data);
- code += *len + 2;
+ offset += len;
break;
}
}
- if (buflen)
+ if (offset < buflen)
return -EINVAL;
return 0;
}
int dhcp_option_parse(DHCPMessage *message, size_t len,
- dhcp_option_cb_t cb, void *user_data)
-{
+ 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;
+ int r;
if (!message)
return -EINVAL;
len -= sizeof(DHCPMessage);
- res = parse_options(opt, len, &overload, &message_type,
- cb, user_data);
- if (res < 0)
- return res;
+ r = parse_options(message->options, len, &overload, &message_type,
+ cb, user_data);
+ if (r < 0)
+ return r;
if (overload & DHCP_OVERLOAD_FILE) {
- res = parse_options(message->file, sizeof(message->file),
+ r = parse_options(message->file, sizeof(message->file),
NULL, &message_type, cb, user_data);
- if (res < 0)
- return res;
+ if (r < 0)
+ return r;
}
if (overload & DHCP_OVERLOAD_SNAME) {
- res = parse_options(message->sname, sizeof(message->sname),
+ r = parse_options(message->sname, sizeof(message->sname),
NULL, &message_type, cb, user_data);
- if (res < 0)
- return res;
+ if (r < 0)
+ return r;
}
if (message_type)
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