diff options
Diffstat (limited to 'networking/udhcp/options.c')
| -rw-r--r-- | networking/udhcp/options.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c new file mode 100644 index 000000000..58144728e --- /dev/null +++ b/networking/udhcp/options.c @@ -0,0 +1,230 @@ +/* + * options.c -- DHCP server option packet tools + * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001 + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "debug.h" +#include "dhcpd.h" +#include "files.h" +#include "options.h" +#include "leases.h" + + +/* supported options are easily added here */ +struct dhcp_option 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}, + {"ntpsrv", OPTION_IP | OPTION_LIST, 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). */ +unsigned char *get_option(struct dhcpMessage *packet, int code) +{ + int i, length; + unsigned char *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(unsigned char *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(unsigned char *optionptr, unsigned char *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(unsigned char *optionptr, unsigned char code, u_int32_t data) +{ + char length = 0; + int i; + unsigned char option[2 + 4]; + unsigned char *u8; + u_int16_t *u16; + u_int32_t *u32; + u_int32_t aligned; + u8 = (unsigned char *) &aligned; + u16 = (u_int16_t *) &aligned; + u32 = &aligned; + + for (i = 0; options[i].code; i++) + if (options[i].code == code) { + length = option_lengths[options[i].flags & TYPE_MASK]; + } + + if (!length) { + DEBUG(LOG_ERR, "Could not add option 0x%02x", code); + return 0; + } + + option[OPT_CODE] = code; + option[OPT_LEN] = length; + + switch (length) { + case 1: *u8 = data; break; + case 2: *u16 = data; break; + case 4: *u32 = data; break; + } + memcpy(option + 2, &aligned, length); + return add_option_string(optionptr, option); +} + + +/* find option 'code' in opt_list */ +struct option_set *find_option(struct option_set *opt_list, char code) +{ + while (opt_list && opt_list->data[OPT_CODE] < code) + opt_list = opt_list->next; + + if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list; + else return NULL; +} + + +/* add an option to the opt_list */ +void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length) +{ + struct option_set *existing, *new, **curr; + + /* add it to an existing option */ + if ((existing = find_option(*opt_list, option->code))) { + DEBUG(LOG_INFO, "Attaching option %s to existing member of list", option->name); + if (option->flags & OPTION_LIST) { + if (existing->data[OPT_LEN] + length <= 255) { + existing->data = realloc(existing->data, + existing->data[OPT_LEN] + length + 2); + memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length); + existing->data[OPT_LEN] += length; + } /* else, ignore the data, we could put this in a second option in the future */ + } /* else, ignore the new data */ + } else { + DEBUG(LOG_INFO, "Attaching option %s to list", option->name); + + /* make a new option */ + new = malloc(sizeof(struct option_set)); + new->data = malloc(length + 2); + new->data[OPT_CODE] = option->code; + new->data[OPT_LEN] = length; + memcpy(new->data + 2, buffer, length); + + curr = opt_list; + while (*curr && (*curr)->data[OPT_CODE] < option->code) + curr = &(*curr)->next; + + new->next = *curr; + *curr = new; + } +} |