add back in udhcp support

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;
+}