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-rw-r--r--networking/udhcp/options.c172
1 files changed, 172 insertions, 0 deletions
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
new file mode 100644
index 0000000..d394b4c
--- /dev/null
+++ b/networking/udhcp/options.c
@@ -0,0 +1,172 @@
+/*
+ * options.c -- DHCP server option packet tools
+ * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "common.h"
+#include "dhcpd.h"
+#include "options.h"
+#include "files.h"
+
+
+/* supported options are easily added here */
+struct dhcp_option dhcp_options[] = {
+ /* name[10] flags code */
+ {"subnet", OPTION_IP | OPTION_REQ, 0x01},
+ {"timezone", OPTION_S32, 0x02},
+ {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
+ {"timesvr", OPTION_IP | OPTION_LIST, 0x04},
+ {"namesvr", OPTION_IP | OPTION_LIST, 0x05},
+ {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
+ {"logsvr", OPTION_IP | OPTION_LIST, 0x07},
+ {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
+ {"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
+ {"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
+ {"bootsize", OPTION_U16, 0x0d},
+ {"domain", OPTION_STRING | OPTION_REQ, 0x0f},
+ {"swapsvr", OPTION_IP, 0x10},
+ {"rootpath", OPTION_STRING, 0x11},
+ {"ipttl", OPTION_U8, 0x17},
+ {"mtu", OPTION_U16, 0x1a},
+ {"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
+ {"nisdomain", OPTION_STRING | OPTION_REQ, 0x28},
+ {"nissrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x29},
+ {"ntpsrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a},
+ {"wins", OPTION_IP | OPTION_LIST, 0x2c},
+ {"requestip", OPTION_IP, 0x32},
+ {"lease", OPTION_U32, 0x33},
+ {"dhcptype", OPTION_U8, 0x35},
+ {"serverid", OPTION_IP, 0x36},
+ {"message", OPTION_STRING, 0x38},
+ {"tftp", OPTION_STRING, 0x42},
+ {"bootfile", OPTION_STRING, 0x43},
+ {"", 0x00, 0x00}
+};
+
+/* Lengths of the different option types */
+int option_lengths[] = {
+ [OPTION_IP] = 4,
+ [OPTION_IP_PAIR] = 8,
+ [OPTION_BOOLEAN] = 1,
+ [OPTION_STRING] = 1,
+ [OPTION_U8] = 1,
+ [OPTION_U16] = 2,
+ [OPTION_S16] = 2,
+ [OPTION_U32] = 4,
+ [OPTION_S32] = 4
+};
+
+
+/* get an option with bounds checking (warning, not aligned). */
+uint8_t *get_option(struct dhcpMessage *packet, int code)
+{
+ int i, length;
+ uint8_t *optionptr;
+ int over = 0, done = 0, curr = OPTION_FIELD;
+
+ optionptr = packet->options;
+ i = 0;
+ length = 308;
+ while (!done) {
+ if (i >= length) {
+ LOG(LOG_WARNING, "bogus packet, option fields too long.");
+ return NULL;
+ }
+ if (optionptr[i + OPT_CODE] == code) {
+ if (i + 1 + optionptr[i + OPT_LEN] >= length) {
+ LOG(LOG_WARNING, "bogus packet, option fields too long.");
+ return NULL;
+ }
+ return optionptr + i + 2;
+ }
+ switch (optionptr[i + OPT_CODE]) {
+ case DHCP_PADDING:
+ i++;
+ break;
+ case DHCP_OPTION_OVER:
+ if (i + 1 + optionptr[i + OPT_LEN] >= length) {
+ LOG(LOG_WARNING, "bogus packet, option fields too long.");
+ return NULL;
+ }
+ over = optionptr[i + 3];
+ i += optionptr[OPT_LEN] + 2;
+ break;
+ case DHCP_END:
+ if (curr == OPTION_FIELD && over & FILE_FIELD) {
+ optionptr = packet->file;
+ i = 0;
+ length = 128;
+ curr = FILE_FIELD;
+ } else if (curr == FILE_FIELD && over & SNAME_FIELD) {
+ optionptr = packet->sname;
+ i = 0;
+ length = 64;
+ curr = SNAME_FIELD;
+ } else done = 1;
+ break;
+ default:
+ i += optionptr[OPT_LEN + i] + 2;
+ }
+ }
+ return NULL;
+}
+
+
+/* return the position of the 'end' option (no bounds checking) */
+int end_option(uint8_t *optionptr)
+{
+ int i = 0;
+
+ while (optionptr[i] != DHCP_END) {
+ if (optionptr[i] == DHCP_PADDING) i++;
+ else i += optionptr[i + OPT_LEN] + 2;
+ }
+ return i;
+}
+
+
+/* add an option string to the options (an option string contains an option code,
+ * length, then data) */
+int add_option_string(uint8_t *optionptr, uint8_t *string)
+{
+ int end = end_option(optionptr);
+
+ /* end position + string length + option code/length + end option */
+ if (end + string[OPT_LEN] + 2 + 1 >= 308) {
+ LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!", string[OPT_CODE]);
+ return 0;
+ }
+ DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]);
+ memcpy(optionptr + end, string, string[OPT_LEN] + 2);
+ optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
+ return string[OPT_LEN] + 2;
+}
+
+
+/* add a one to four byte option to a packet */
+int add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
+{
+ struct dhcp_option *dh;
+
+ for (dh=dhcp_options; dh->code; dh++) {
+ if (dh->code == code) {
+ uint8_t option[6], len;
+
+ option[OPT_CODE] = code;
+ len = option_lengths[dh->flags & TYPE_MASK];
+ option[OPT_LEN] = len;
+ if (__BYTE_ORDER == __BIG_ENDIAN)
+ data <<= 8 * (4 - len);
+ /* This memcpy is for broken processors which can't
+ * handle a simple unaligned 32-bit assignment */
+ memcpy(&option[OPT_DATA], &data, 4);
+ return add_option_string(optionptr, option);
+ }
+ }
+
+ DEBUG(LOG_ERR, "Could not add option 0x%02x", code);
+ return 0;
+}