added full udhcp integration
This commit is contained in:
Russ Dill
230
networking/udhcp/options.c
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230
networking/udhcp/options.c
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/*
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* options.c -- DHCP server option packet tools
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* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "debug.h"
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#include "dhcpd.h"
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#include "files.h"
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#include "options.h"
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#include "leases.h"
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/* supported options are easily added here */
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struct dhcp_option options[] = {
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/* name[10] flags code */
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{"subnet", OPTION_IP | OPTION_REQ, 0x01},
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{"timezone", OPTION_S32, 0x02},
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{"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
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{"timesvr", OPTION_IP | OPTION_LIST, 0x04},
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{"namesvr", OPTION_IP | OPTION_LIST, 0x05},
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{"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
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{"logsvr", OPTION_IP | OPTION_LIST, 0x07},
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{"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
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{"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
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{"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
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{"bootsize", OPTION_U16, 0x0d},
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{"domain", OPTION_STRING | OPTION_REQ, 0x0f},
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{"swapsvr", OPTION_IP, 0x10},
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{"rootpath", OPTION_STRING, 0x11},
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{"ipttl", OPTION_U8, 0x17},
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{"mtu", OPTION_U16, 0x1a},
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{"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
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{"ntpsrv", OPTION_IP | OPTION_LIST, 0x2a},
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{"wins", OPTION_IP | OPTION_LIST, 0x2c},
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{"requestip", OPTION_IP, 0x32},
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{"lease", OPTION_U32, 0x33},
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{"dhcptype", OPTION_U8, 0x35},
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{"serverid", OPTION_IP, 0x36},
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{"message", OPTION_STRING, 0x38},
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{"tftp", OPTION_STRING, 0x42},
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{"bootfile", OPTION_STRING, 0x43},
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{"", 0x00, 0x00}
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};
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/* Lengths of the different option types */
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int option_lengths[] = {
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[OPTION_IP] = 4,
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[OPTION_IP_PAIR] = 8,
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[OPTION_BOOLEAN] = 1,
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[OPTION_STRING] = 1,
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[OPTION_U8] = 1,
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[OPTION_U16] = 2,
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[OPTION_S16] = 2,
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[OPTION_U32] = 4,
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[OPTION_S32] = 4
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};
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/* get an option with bounds checking (warning, not aligned). */
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unsigned char *get_option(struct dhcpMessage *packet, int code)
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{
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int i, length;
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unsigned char *optionptr;
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int over = 0, done = 0, curr = OPTION_FIELD;
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optionptr = packet->options;
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i = 0;
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length = 308;
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while (!done) {
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if (i >= length) {
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LOG(LOG_WARNING, "bogus packet, option fields too long.");
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return NULL;
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}
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if (optionptr[i + OPT_CODE] == code) {
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if (i + 1 + optionptr[i + OPT_LEN] >= length) {
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LOG(LOG_WARNING, "bogus packet, option fields too long.");
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return NULL;
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}
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return optionptr + i + 2;
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}
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switch (optionptr[i + OPT_CODE]) {
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case DHCP_PADDING:
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i++;
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break;
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case DHCP_OPTION_OVER:
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if (i + 1 + optionptr[i + OPT_LEN] >= length) {
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LOG(LOG_WARNING, "bogus packet, option fields too long.");
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return NULL;
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}
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over = optionptr[i + 3];
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i += optionptr[OPT_LEN] + 2;
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break;
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case DHCP_END:
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if (curr == OPTION_FIELD && over & FILE_FIELD) {
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optionptr = packet->file;
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i = 0;
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length = 128;
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curr = FILE_FIELD;
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} else if (curr == FILE_FIELD && over & SNAME_FIELD) {
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optionptr = packet->sname;
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i = 0;
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length = 64;
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curr = SNAME_FIELD;
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} else done = 1;
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break;
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default:
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i += optionptr[OPT_LEN + i] + 2;
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}
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}
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return NULL;
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}
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/* return the position of the 'end' option (no bounds checking) */
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int end_option(unsigned char *optionptr)
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{
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int i = 0;
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while (optionptr[i] != DHCP_END) {
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if (optionptr[i] == DHCP_PADDING) i++;
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else i += optionptr[i + OPT_LEN] + 2;
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}
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return i;
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}
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/* add an option string to the options (an option string contains an option code,
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* length, then data) */
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int add_option_string(unsigned char *optionptr, unsigned char *string)
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{
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int end = end_option(optionptr);
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/* end position + string length + option code/length + end option */
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if (end + string[OPT_LEN] + 2 + 1 >= 308) {
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LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!", string[OPT_CODE]);
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return 0;
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}
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DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]);
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memcpy(optionptr + end, string, string[OPT_LEN] + 2);
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optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
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return string[OPT_LEN] + 2;
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}
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/* add a one to four byte option to a packet */
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int add_simple_option(unsigned char *optionptr, unsigned char code, u_int32_t data)
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{
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char length = 0;
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int i;
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unsigned char option[2 + 4];
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unsigned char *u8;
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u_int16_t *u16;
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u_int32_t *u32;
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u_int32_t aligned;
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u8 = (unsigned char *) &aligned;
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u16 = (u_int16_t *) &aligned;
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u32 = &aligned;
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for (i = 0; options[i].code; i++)
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if (options[i].code == code) {
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length = option_lengths[options[i].flags & TYPE_MASK];
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}
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if (!length) {
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DEBUG(LOG_ERR, "Could not add option 0x%02x", code);
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return 0;
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}
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option[OPT_CODE] = code;
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option[OPT_LEN] = length;
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switch (length) {
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case 1: *u8 = data; break;
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case 2: *u16 = data; break;
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case 4: *u32 = data; break;
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}
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memcpy(option + 2, &aligned, length);
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return add_option_string(optionptr, option);
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}
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/* find option 'code' in opt_list */
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struct option_set *find_option(struct option_set *opt_list, char code)
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{
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while (opt_list && opt_list->data[OPT_CODE] < code)
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opt_list = opt_list->next;
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if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
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else return NULL;
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}
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/* add an option to the opt_list */
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void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
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{
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struct option_set *existing, *new, **curr;
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/* add it to an existing option */
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if ((existing = find_option(*opt_list, option->code))) {
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DEBUG(LOG_INFO, "Attaching option %s to existing member of list", option->name);
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if (option->flags & OPTION_LIST) {
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if (existing->data[OPT_LEN] + length <= 255) {
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existing->data = realloc(existing->data,
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existing->data[OPT_LEN] + length + 2);
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memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
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existing->data[OPT_LEN] += length;
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} /* else, ignore the data, we could put this in a second option in the future */
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} /* else, ignore the new data */
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} else {
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DEBUG(LOG_INFO, "Attaching option %s to list", option->name);
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/* make a new option */
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new = malloc(sizeof(struct option_set));
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new->data = malloc(length + 2);
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new->data[OPT_CODE] = option->code;
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new->data[OPT_LEN] = length;
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memcpy(new->data + 2, buffer, length);
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curr = opt_list;
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while (*curr && (*curr)->data[OPT_CODE] < option->code)
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curr = &(*curr)->next;
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new->next = *curr;
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*curr = new;
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}
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}
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