257 lines
8.7 KiB
C
257 lines
8.7 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
|
|
*
|
|
* Licensed under GPLv2, see file LICENSE in this tarball for details.
|
|
*/
|
|
|
|
#include "common.h"
|
|
#include "dhcpd.h"
|
|
#include "options.h"
|
|
|
|
|
|
/* Supported options are easily added here */
|
|
const struct dhcp_option dhcp_options[] = {
|
|
/* flags code */
|
|
{ OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
|
|
{ OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
|
|
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
|
|
{ OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
|
|
{ OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
|
|
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
|
|
{ OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
|
|
{ OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
|
|
{ OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
|
|
{ OPTION_STRING | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
|
|
{ OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
|
|
{ OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
|
|
{ OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
|
|
{ OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
|
|
{ OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
|
|
{ OPTION_U16 , 0x1a }, /* DHCP_MTU */
|
|
{ OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
|
|
{ OPTION_STRING , 0x28 }, /* nisdomain */
|
|
{ OPTION_IP | OPTION_LIST , 0x29 }, /* nissrv */
|
|
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
|
|
{ OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
|
|
{ OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
|
|
{ OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
|
|
{ OPTION_U8 , 0x35 }, /* dhcptype */
|
|
{ OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
|
|
{ OPTION_STRING , 0x38 }, /* DHCP_MESSAGE */
|
|
{ OPTION_STRING , 0x3C }, /* DHCP_VENDOR */
|
|
{ OPTION_STRING , 0x3D }, /* DHCP_CLIENT_ID */
|
|
{ OPTION_STRING , 0x42 }, /* tftp */
|
|
{ OPTION_STRING , 0x43 }, /* bootfile */
|
|
{ OPTION_STRING , 0x4D }, /* userclass */
|
|
#if ENABLE_FEATURE_UDHCP_RFC3397
|
|
{ OPTION_STR1035 | OPTION_LIST , 0x77 }, /* search */
|
|
#endif
|
|
/* MSIE's "Web Proxy Autodiscovery Protocol" support */
|
|
{ OPTION_STRING , 0xfc }, /* wpad */
|
|
|
|
/* Options below have no match in dhcp_option_strings[],
|
|
* are not passed to dhcpc scripts, and cannot be specified
|
|
* with "option XXX YYY" syntax in dhcpd config file. */
|
|
|
|
{ OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
|
|
{ } /* zeroed terminating entry */
|
|
};
|
|
|
|
/* Used for converting options from incoming packets to env variables
|
|
* for udhcpc stript */
|
|
/* Must match dhcp_options[] order */
|
|
const char dhcp_option_strings[] ALIGN1 =
|
|
"subnet" "\0" /* DHCP_SUBNET */
|
|
"timezone" "\0" /* DHCP_TIME_OFFSET */
|
|
"router" "\0" /* DHCP_ROUTER */
|
|
"timesrv" "\0" /* DHCP_TIME_SERVER */
|
|
"namesrv" "\0" /* DHCP_NAME_SERVER */
|
|
"dns" "\0" /* DHCP_DNS_SERVER */
|
|
"logsrv" "\0" /* DHCP_LOG_SERVER */
|
|
"cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
|
|
"lprsrv" "\0" /* DHCP_LPR_SERVER */
|
|
"hostname" "\0" /* DHCP_HOST_NAME */
|
|
"bootsize" "\0" /* DHCP_BOOT_SIZE */
|
|
"domain" "\0" /* DHCP_DOMAIN_NAME */
|
|
"swapsrv" "\0" /* DHCP_SWAP_SERVER */
|
|
"rootpath" "\0" /* DHCP_ROOT_PATH */
|
|
"ipttl" "\0" /* DHCP_IP_TTL */
|
|
"mtu" "\0" /* DHCP_MTU */
|
|
"broadcast" "\0" /* DHCP_BROADCAST */
|
|
"nisdomain" "\0" /* */
|
|
"nissrv" "\0" /* */
|
|
"ntpsrv" "\0" /* DHCP_NTP_SERVER */
|
|
"wins" "\0" /* DHCP_WINS_SERVER */
|
|
"requestip" "\0" /* DHCP_REQUESTED_IP */
|
|
"lease" "\0" /* DHCP_LEASE_TIME */
|
|
"dhcptype" "\0" /* */
|
|
"serverid" "\0" /* DHCP_SERVER_ID */
|
|
"message" "\0" /* DHCP_MESSAGE */
|
|
"vendorclass" "\0" /* DHCP_VENDOR */
|
|
"clientid" "\0" /* DHCP_CLIENT_ID */
|
|
"tftp" "\0"
|
|
"bootfile" "\0"
|
|
"userclass" "\0"
|
|
#if ENABLE_FEATURE_UDHCP_RFC3397
|
|
"search" "\0"
|
|
#endif
|
|
/* MSIE's "Web Proxy Autodiscovery Protocol" support */
|
|
"wpad" "\0"
|
|
;
|
|
|
|
|
|
/* Lengths of the different option types */
|
|
const uint8_t dhcp_option_lengths[] ALIGN1 = {
|
|
[OPTION_IP] = 4,
|
|
[OPTION_IP_PAIR] = 8,
|
|
[OPTION_BOOLEAN] = 1,
|
|
[OPTION_STRING] = 1,
|
|
#if ENABLE_FEATURE_UDHCP_RFC3397
|
|
[OPTION_STR1035] = 1,
|
|
#endif
|
|
[OPTION_U8] = 1,
|
|
[OPTION_U16] = 2,
|
|
[OPTION_S16] = 2,
|
|
[OPTION_U32] = 4,
|
|
[OPTION_S32] = 4
|
|
};
|
|
|
|
|
|
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
|
|
static void log_option(const char *pfx, const uint8_t *opt)
|
|
{
|
|
if (dhcp_verbose >= 2) {
|
|
char buf[256 * 2 + 2];
|
|
*bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
|
|
bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
|
|
}
|
|
}
|
|
#else
|
|
# define log_option(pfx, opt) ((void)0)
|
|
#endif
|
|
|
|
|
|
/* get an option with bounds checking (warning, result is not aligned). */
|
|
uint8_t* FAST_FUNC get_option(struct dhcp_packet *packet, int code)
|
|
{
|
|
uint8_t *optionptr;
|
|
int len;
|
|
int rem;
|
|
int overload = 0;
|
|
enum {
|
|
FILE_FIELD101 = FILE_FIELD * 0x101,
|
|
SNAME_FIELD101 = SNAME_FIELD * 0x101,
|
|
};
|
|
|
|
/* option bytes: [code][len][data1][data2]..[dataLEN] */
|
|
optionptr = packet->options;
|
|
rem = sizeof(packet->options);
|
|
while (1) {
|
|
if (rem <= 0) {
|
|
bb_error_msg("bogus packet, malformed option field");
|
|
return NULL;
|
|
}
|
|
if (optionptr[OPT_CODE] == DHCP_PADDING) {
|
|
rem--;
|
|
optionptr++;
|
|
continue;
|
|
}
|
|
if (optionptr[OPT_CODE] == DHCP_END) {
|
|
if ((overload & FILE_FIELD101) == FILE_FIELD) {
|
|
/* can use packet->file, and didn't look at it yet */
|
|
overload |= FILE_FIELD101; /* "we looked at it" */
|
|
optionptr = packet->file;
|
|
rem = sizeof(packet->file);
|
|
continue;
|
|
}
|
|
if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
|
|
/* can use packet->sname, and didn't look at it yet */
|
|
overload |= SNAME_FIELD101; /* "we looked at it" */
|
|
optionptr = packet->sname;
|
|
rem = sizeof(packet->sname);
|
|
continue;
|
|
}
|
|
break;
|
|
}
|
|
len = 2 + optionptr[OPT_LEN];
|
|
rem -= len;
|
|
if (rem < 0)
|
|
continue; /* complain and return NULL */
|
|
|
|
if (optionptr[OPT_CODE] == code) {
|
|
log_option("Option found", optionptr);
|
|
return optionptr + OPT_DATA;
|
|
}
|
|
|
|
if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
|
|
overload |= optionptr[OPT_DATA];
|
|
/* fall through */
|
|
}
|
|
optionptr += len;
|
|
}
|
|
|
|
/* log3 because udhcpc uses it a lot - very noisy */
|
|
log3("Option 0x%02x not found", code);
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/* return the position of the 'end' option (no bounds checking) */
|
|
int FAST_FUNC end_option(uint8_t *optionptr)
|
|
{
|
|
int i = 0;
|
|
|
|
while (optionptr[i] != DHCP_END) {
|
|
if (optionptr[i] != DHCP_PADDING)
|
|
i += optionptr[i + OPT_LEN] + 1;
|
|
i++;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
|
|
/* add an option string to the options */
|
|
/* option bytes: [code][len][data1][data2]..[dataLEN] */
|
|
int FAST_FUNC 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 >= DHCP_OPTIONS_BUFSIZE) {
|
|
bb_error_msg("option 0x%02x did not fit into the packet",
|
|
string[OPT_CODE]);
|
|
return 0;
|
|
}
|
|
log_option("Adding option", string);
|
|
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 FAST_FUNC add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
|
|
{
|
|
const 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 = dhcp_option_lengths[dh->flags & TYPE_MASK];
|
|
option[OPT_LEN] = len;
|
|
if (BB_BIG_ENDIAN)
|
|
data <<= 8 * (4 - len);
|
|
/* Assignment is unaligned! */
|
|
move_to_unaligned32(&option[OPT_DATA], data);
|
|
return add_option_string(optionptr, option);
|
|
}
|
|
}
|
|
|
|
bb_error_msg("cannot add option 0x%02x", code);
|
|
return 0;
|
|
}
|