diff options
Diffstat (limited to 'networking/udhcp/options.c')
| -rw-r--r-- | networking/udhcp/options.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c new file mode 100644 index 0000000..6bf99e2 --- /dev/null +++ b/networking/udhcp/options.c @@ -0,0 +1,234 @@ +/* vi: set sw=4 ts=4: */ +/* + * options.c -- DHCP server option packet tools + * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001 + */ + +#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 +}; + + +/* get an option with bounds checking (warning, not aligned). */ +uint8_t* FAST_FUNC get_option(struct dhcpMessage *packet, int code) +{ + int i, length; + uint8_t *optionptr; + int over = 0; + int curr = OPTION_FIELD; + + optionptr = packet->options; + i = 0; + length = sizeof(packet->options); + while (1) { + 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 = sizeof(packet->file); + curr = FILE_FIELD; + } else if (curr == FILE_FIELD && (over & SNAME_FIELD)) { + optionptr = packet->sname; + i = 0; + length = sizeof(packet->sname); + curr = SNAME_FIELD; + } else + return NULL; + break; + default: + i += optionptr[OPT_LEN + i] + 2; + } + } + 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++; + 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 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; + } + 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 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); + /* This memcpy is for 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; +} |