Implement RFC3442, the Classless Static Route option.
The original DHCP specification includes a route option but it supports only class-based routes. RFC3442 adds support for specifying the netmask width for each static route. A variable length encoding is used to minimize the size of this option. PR: bin/99534 Submitted by: Andrey V. Elsukov <bu7cher@yandex.ru> Reviewed by: brooks
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emaste
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73c9958792
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@ -89,6 +89,8 @@ read_client_conf(void)
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[top_level_config.requested_option_count++] = DHO_BROADCAST_ADDRESS;
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top_level_config.requested_options
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[top_level_config.requested_option_count++] = DHO_TIME_OFFSET;
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top_level_config.requested_options
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[top_level_config.requested_option_count++] = DHO_CLASSLESS_ROUTES;
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top_level_config.requested_options
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[top_level_config.requested_option_count++] = DHO_ROUTERS;
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top_level_config.requested_options
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@ -86,8 +86,43 @@ add_new_alias() {
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fi
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}
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fill_classless_routes() {
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set $1
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while [ $# -gt 5 ]; do
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if [ $1 -eq 0 ]; then
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route="default"
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elif [ $1 -le 8 ]; then
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route="$2.0.0.0/$1"
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shift
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elif [ $1 -le 16 ]; then
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route="$2.$3.0.0/$1"
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shift; shift
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elif [ $1 -le 24 ]; then
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route="$2.$3.$4.0/$1"
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shift; shift; shift
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else
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route="$2.$3.$4.$5/$1"
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shift; shift; shift; shift
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fi
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shift
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router="$1.$2.$3.$4"
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classless_routes="$classless_routes $route $router"
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shift; shift; shift; shift
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done
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}
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delete_old_routes() {
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#route delete "$old_ip_address" $LOCALHOST >/dev/null 2>&1
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if [ -n "$old_classless_routes" ]; then
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fill_classless_routes "$old_classless_routes"
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set $classless_routes
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while [ $# -gt 1 ]; do
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route delete "$1" "$2"
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shift; shift
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done
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return 0;
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fi
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for router in $old_routers; do
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if [ $if_defaultroute = x -o $if_defaultroute = $interface ]; then
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route delete default $route >/dev/null 2>&1
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@ -107,6 +142,31 @@ delete_old_routes() {
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add_new_routes() {
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#route add $new_ip_address $LOCALHOST >/dev/null 2>&1
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# RFC 3442: If the DHCP server returns both a Classless Static
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# Routes option and a Router option, the DHCP client MUST ignore
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# the Router option.
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#
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# DHCP clients that support this option (Classless Static Routes)
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# MUST NOT install the routes specified in the Static Routes
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# option (option code 33) if both a Static Routes option and the
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# Classless Static Routes option are provided.
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if [ -n "$new_classless_routes" ]; then
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fill_classless_routes "$new_classless_routes"
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$LOGGER "New Classless Static Routes ($interface): $classless_routes"
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set $classless_routes
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while [ $# -gt 1 ]; do
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if [ "0.0.0.0" = "$2" ]; then
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route add "$1" -iface "$interface"
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else
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route add "$1" "$2"
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fi
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shift; shift
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done
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return
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fi
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for router in $new_routers; do
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if [ "$new_ip_address" = "$router" ]; then
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route add default -iface $router >/dev/null 2>&1
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@ -115,6 +115,7 @@ struct sockaddr *get_ifa(char *, int);
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void routehandler(struct protocol *);
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void usage(void);
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int check_option(struct client_lease *l, int option);
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int check_classless_option(unsigned char *data, int len);
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int ipv4addrs(char * buf);
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int res_hnok(const char *dn);
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int check_search(const char *srch);
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@ -2374,12 +2375,79 @@ check_option(struct client_lease *l, int option)
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case DHO_DHCP_USER_CLASS_ID:
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case DHO_END:
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return (1);
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case DHO_CLASSLESS_ROUTES:
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return (check_classless_option(l->options[option].data,
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l->options[option].len));
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default:
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warning("unknown dhcp option value 0x%x", option);
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return (unknown_ok);
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}
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}
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/* RFC 3442 The Classless Static Routes option checks */
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int
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check_classless_option(unsigned char *data, int len)
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{
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int i = 0;
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unsigned char width;
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in_addr_t addr, mask;
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if (len < 5) {
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warning("Too small length: %d", len);
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return (0);
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}
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while(i < len) {
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width = data[i++];
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if (width == 0) {
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i += 4;
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continue;
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} else if (width < 9) {
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addr = (in_addr_t)(data[i] << 24);
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i += 1;
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} else if (width < 17) {
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addr = (in_addr_t)(data[i] << 24) +
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(in_addr_t)(data[i + 1] << 16);
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i += 2;
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} else if (width < 25) {
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addr = (in_addr_t)(data[i] << 24) +
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(in_addr_t)(data[i + 1] << 16) +
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(in_addr_t)(data[i + 2] << 8);
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i += 3;
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} else if (width < 33) {
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addr = (in_addr_t)(data[i] << 24) +
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(in_addr_t)(data[i + 1] << 16) +
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(in_addr_t)(data[i + 2] << 8) +
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data[i + 3];
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i += 4;
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} else {
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warning("Incorrect subnet width: %d", width);
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return (0);
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}
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mask = (in_addr_t)(~0) << (32 - width);
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addr = ntohl(addr);
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mask = ntohl(mask);
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/*
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* From RFC 3442:
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* ... After deriving a subnet number and subnet mask
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* from each destination descriptor, the DHCP client
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* MUST zero any bits in the subnet number where the
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* corresponding bit in the mask is zero...
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*/
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if ((addr & mask) != addr) {
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addr &= mask;
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data[i - 1] = (unsigned char)(
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(addr >> (((32 - width)/8)*8)) & 0xFF);
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}
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i += 4;
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}
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if (i > len) {
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warning("Incorrect data length: %d (must be %d)", len, i);
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return (0);
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}
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return (1);
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}
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int
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res_hnok(const char *dn)
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{
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@ -5,8 +5,9 @@ send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
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send dhcp-lease-time 3600;
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supersede domain-name "fugue.com home.vix.com";
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prepend domain-name-servers 127.0.0.1;
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request subnet-mask, broadcast-address, time-offset, routers,
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domain-name, domain-name-servers, host-name;
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request subnet-mask, broadcast-address, time-offset,
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classless-routes, routers, domain-name,
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domain-name-servers, host-name;
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require subnet-mask, domain-name-servers;
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timeout 60;
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retry 60;
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@ -162,6 +162,7 @@ struct dhcp_packet {
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#define DHO_FINGER_SERVER 73
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#define DHO_IRC_SERVER 74
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#define DHO_DHCP_USER_CLASS_ID 77
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#define DHO_CLASSLESS_ROUTES 121
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#define DHO_END 255
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/* DHCP message types. */
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@ -186,7 +186,7 @@ struct option dhcp_options[256] = {
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{ "option-118", "X", &dhcp_universe, 118 },
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{ "option-119", "X", &dhcp_universe, 119 },
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{ "option-120", "X", &dhcp_universe, 120 },
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{ "option-121", "X", &dhcp_universe, 121 },
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{ "classless-routes", "BA", &dhcp_universe, 121 },
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{ "option-122", "X", &dhcp_universe, 122 },
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{ "option-123", "X", &dhcp_universe, 123 },
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{ "option-124", "X", &dhcp_universe, 124 },
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@ -337,6 +337,7 @@ unsigned char dhcp_option_default_priority_list[] = {
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DHO_DHCP_CLIENT_IDENTIFIER,
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DHO_SUBNET_MASK,
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DHO_TIME_OFFSET,
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DHO_CLASSLESS_ROUTES,
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DHO_ROUTERS,
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DHO_TIME_SERVERS,
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DHO_NAME_SERVERS,
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@ -392,7 +393,7 @@ unsigned char dhcp_option_default_priority_list[] = {
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78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92,
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93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106,
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107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118,
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119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130,
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119, 120, 122, 123, 124, 125, 126, 127, 128, 129, 130,
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131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142,
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143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154,
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155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166,
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