mirror of
https://github.com/sheumann/hush.git
synced 2024-08-16 09:29:16 +00:00
177 lines
4.7 KiB
C
177 lines
4.7 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* 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},
|
|
{"vendorclass", OPTION_STRING, 0x3C},
|
|
{"clientid", OPTION_STRING, 0x3D},
|
|
{"tftp", OPTION_STRING, 0x42},
|
|
{"bootfile", OPTION_STRING, 0x43},
|
|
{"userclass", OPTION_STRING, 0x4D},
|
|
{"", 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) {
|
|
bb_error_msg("Bogus packet, option fields too long");
|
|
return NULL;
|
|
}
|
|
if (optionptr[i + OPT_CODE] == code) {
|
|
if (i + 1 + optionptr[i + OPT_LEN] >= length) {
|
|
bb_error_msg("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) {
|
|
bb_error_msg("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) {
|
|
bb_error_msg("Option 0x%02x did not fit into the packet",
|
|
string[OPT_CODE]);
|
|
return 0;
|
|
}
|
|
DEBUG("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 (BB_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);
|
|
}
|
|
}
|
|
|
|
bb_error_msg("cannot add option 0x%02x", code);
|
|
return 0;
|
|
}
|