ppp: ipv6: multiple prefixes, route option, rdnss option implementation

14 files changed, 940 insertions, 178 deletions

diff --git a/accel-pppd/cli/show_sessions.c b/accel-pppd/cli/show_sessions.c
index d7a8a82..9019986 100644
--- a/accel-pppd/cli/show_sessions.c
+++ b/accel-pppd/cli/show_sessions.c
@@ -8,6 +8,7 @@
 #include "triton.h"
 #include "events.h"
 #include "ppp.h"
+#include "ipdb.h"
 #include "cli.h"
 #include "utils.h"
 #include "log.h"
@@ -382,7 +383,7 @@ static void print_username(const struct ppp_t *ppp, char *buf)
 
 static void print_ip(const struct ppp_t *ppp, char *buf)
 {
-	u_inet_ntoa(ppp->peer_ipaddr, buf);
+	u_inet_ntoa(ppp->ipv4 ? ppp->ipv4->peer_addr : 0, buf);
 }
 
 static void print_type(const struct ppp_t *ppp, char *buf)
diff --git a/accel-pppd/cli/std_cmd.c b/accel-pppd/cli/std_cmd.c
index 1c8e149..24e5228 100644
--- a/accel-pppd/cli/std_cmd.c
+++ b/accel-pppd/cli/std_cmd.c
@@ -9,6 +9,7 @@
 #include "triton.h"
 #include "events.h"
 #include "ppp.h"
+#include "ipdb.h"
 #include "cli.h"
 #include "utils.h"
 #include "log.h"
@@ -166,7 +167,7 @@ static int terminate_exec2(int key, char * const *f, int f_cnt, void *cli)
 					continue;
 				break;
 			case 1:
-				if (ppp->peer_ipaddr != ipaddr)
+				if (ppp->ipv4 && ppp->ipv4->peer_addr != ipaddr)
 					continue;
 				break;
 			case 2:
diff --git a/accel-pppd/extra/ipv6pool.c b/accel-pppd/extra/ipv6pool.c
index 306d5bd..5a1a606 100644
--- a/accel-pppd/extra/ipv6pool.c
+++ b/accel-pppd/extra/ipv6pool.c
@@ -39,6 +39,7 @@ static void generate_pool(struct in6_addr *addr, int mask, int prefix_len)
 {
 	struct ippool_item_t *it;
 	uint64_t ip, endip, step;
+	struct ipv6db_addr_t *a;
 
 	ip = be64toh(*(uint64_t *)addr->s6_addr);
 	endip = ip | ((1llu << (64 - mask)) - 1);
@@ -46,8 +47,13 @@ static void generate_pool(struct in6_addr *addr, int mask, int prefix_len)
 	
 	for (; ip <= endip; ip += step) {
 		it = malloc(sizeof(*it));
-		*(uint64_t *)it->it.addr.s6_addr = htobe64(ip);
-		it->it.prefix_len = prefix_len;
+		INIT_LIST_HEAD(&it->it.addr_list);
+		INIT_LIST_HEAD(&it->it.route_list);
+		a = malloc(sizeof(*a));
+		memset(a, 0, sizeof(*a));
+		*(uint64_t *)a->addr.s6_addr = htobe64(ip);
+		a->prefix_len = prefix_len;
+		list_add_tail(&a->entry, &it->it.addr_list);
 		list_add_tail(&it->entry, &ippool);
 	}
 }
@@ -97,27 +103,36 @@ err:
 	_free(val);
 }
 
-static void generate_intf_id(struct ppp_t *ppp, struct in6_addr *addr)
+static uint64_t generate_intf_id(struct ppp_t *ppp)
 {
 	char str[4];
 	int i, n;
+	union {
+		uint64_t intf_id;
+		uint16_t addr16[4];
+	} u;
 	
 	switch (conf_intf_id) {
 		case INTF_ID_FIXED:
-			*(uint64_t *)(&addr->s6_addr32[2]) = conf_intf_id_val;
+			return conf_intf_id_val;
 			break;
 		case INTF_ID_RANDOM:
-			read(urandom_fd, &addr->s6_addr32[2], 8);
+			read(urandom_fd, &u, sizeof(u));
 			break;
 		case INTF_ID_CSID:
 			break;
 		case INTF_ID_IPV4:
-			for (i = 0; i < 4; i++) {
-				sprintf(str, "%i", (ppp->peer_ipaddr >> (i*8)) & 0xff);
-				sscanf(str, "%x", &n);
-				addr->s6_addr16[4 + i] = htons(n);
-			}
+			if (ppp->ipv4) {
+				for (i = 0; i < 4; i++) {
+					sprintf(str, "%i", (ppp->ipv4->peer_addr >> (i*8)) & 0xff);
+					sscanf(str, "%x", &n);
+					u.addr16[i] = htons(n);
+				}
+			} else
+				read(urandom_fd, &u, sizeof(u));
 	}
+
+	return u.intf_id;
 }
 
 static struct ipv6db_item_t *get_ip(struct ppp_t *ppp)
@@ -133,7 +148,7 @@ static struct ipv6db_item_t *get_ip(struct ppp_t *ppp)
 	spin_unlock(&pool_lock);
 
 	if (it)
-		generate_intf_id(ppp, &it->it.addr);
+		it->it.intf_id = generate_intf_id(ppp);
 
 	return it ? &it->it : NULL;
 }
diff --git a/accel-pppd/extra/net-snmp/sessionTable_data_access.c b/accel-pppd/extra/net-snmp/sessionTable_data_access.c
index 847197a..0d38e5d 100644
--- a/accel-pppd/extra/net-snmp/sessionTable_data_access.c
+++ b/accel-pppd/extra/net-snmp/sessionTable_data_access.c
@@ -16,6 +16,7 @@
 #include "sessionTable_data_access.h"
 
 #include "ppp.h"
+#include "ipdb.h"
 
 /** @ingroup interface
  * @addtogroup data_access data_access: Routines to access data
@@ -227,7 +228,7 @@ sessionTable_container_load(netsnmp_container *container)
 				else
 					ppp->username = strdup("");
 
-				rowreq_ctx->data->peer_addr = ppp->peer_ipaddr;
+				rowreq_ctx->data->peer_addr = ppp->ipv4 ? ppp->ipv4->peer_addr : 0;
 				rowreq_ctx->data->type = ppp->ctrl->type;
 				rowreq_ctx->data->state = ppp->state;
 				rowreq_ctx->data->uptime = (ppp->stop_time ? ppp->stop_time : t) - ppp->start_time;
diff --git a/accel-pppd/extra/net-snmp/terminate.c b/accel-pppd/extra/net-snmp/terminate.c
index bd38577..abe92df 100644
--- a/accel-pppd/extra/net-snmp/terminate.c
+++ b/accel-pppd/extra/net-snmp/terminate.c
@@ -12,6 +12,7 @@
 
 #include "triton.h"
 #include "ppp.h"
+#include "ipdb.h"
 
 #include "terminate.h"
 
@@ -65,7 +66,7 @@ static void terminate_by_ip(const char *val, size_t len)
 	
 	pthread_rwlock_rdlock(&ppp_lock);
 	list_for_each_entry(ppp, &ppp_list, entry) {
-		if (ppp->peer_ipaddr != addr)
+		if (!ppp->ipv4 || ppp->ipv4->peer_addr != addr)
 			continue;
 		triton_context_call(ppp->ctrl->ctx, (triton_event_func)__terminate, ppp);
 		break;
diff --git a/accel-pppd/extra/pppd_compat.c b/accel-pppd/extra/pppd_compat.c
index aa6f6b5..32a5def 100644
--- a/accel-pppd/extra/pppd_compat.c
+++ b/accel-pppd/extra/pppd_compat.c
@@ -14,6 +14,7 @@
 
 #include "events.h"
 #include "ppp.h"
+#include "ipdb.h"
 #include "log.h"
 #include "utils.h"
 #include "sigchld.h"
@@ -480,8 +481,8 @@ static void fill_argv(char **argv, struct ppp_t *ppp, char *path)
 	argv[1] = ppp->ifname;
 	argv[2] = "none";
 	argv[3] = "0";
-	u_inet_ntoa(ppp->ipaddr, argv[4]);
-	u_inet_ntoa(ppp->peer_ipaddr, argv[5]);
+	u_inet_ntoa(ppp->ipv4 ? ppp->ipv4->addr : 0, argv[4]);
+	u_inet_ntoa(ppp->ipv4 ? ppp->ipv4->peer_addr : 0, argv[5]);
 	argv[6] = ppp->ctrl->calling_station_id;
 	argv[7] = NULL;
 }
diff --git a/accel-pppd/ipdb.h b/accel-pppd/ipdb.h
index 3a717a1..69d5479 100644
--- a/accel-pppd/ipdb.h
+++ b/accel-pppd/ipdb.h
@@ -13,13 +13,21 @@ struct ipv4db_item_t
 	in_addr_t peer_addr;
 };
 
-struct ipv6db_item_t
+struct ipv6db_addr_t
 {
-	struct ipdb_t *owner;
+	struct list_head entry;
 	struct in6_addr addr;
 	int prefix_len;
 };
 
+struct ipv6db_item_t
+{
+	struct ipdb_t *owner;
+	uint64_t intf_id;
+	struct list_head addr_list;
+	struct list_head route_list;
+};
+
 
 struct ipdb_t
 {
diff --git a/accel-pppd/ppp/ipcp_opt_ipaddr.c b/accel-pppd/ppp/ipcp_opt_ipaddr.c
index ac45ac7..f387069 100644
--- a/accel-pppd/ppp/ipcp_opt_ipaddr.c
+++ b/accel-pppd/ppp/ipcp_opt_ipaddr.c
@@ -30,36 +30,36 @@ static void ipaddr_print(void (*print)(const char *fmt,...),struct ipcp_option_t
 struct ipaddr_option_t
 {
 	struct ipcp_option_t opt;
-	struct ipv4db_item_t *ip;
+	struct ppp_t *ppp;
 	int started:1;
 };
 
-static struct ipcp_option_handler_t ipaddr_opt_hnd=
-{
-	.init=ipaddr_init,
-	.send_conf_req=ipaddr_send_conf_req,
-	.send_conf_nak=ipaddr_send_conf_nak,
-	.recv_conf_req=ipaddr_recv_conf_req,
-	.free=ipaddr_free,
-	.print=ipaddr_print,
+static struct ipcp_option_handler_t ipaddr_opt_hnd = {
+	.init          = ipaddr_init,
+	.send_conf_req = ipaddr_send_conf_req,
+	.send_conf_nak = ipaddr_send_conf_nak,
+	.recv_conf_req = ipaddr_recv_conf_req,
+	.free          = ipaddr_free,
+	.print         = ipaddr_print,
 };
 
 static struct ipcp_option_t *ipaddr_init(struct ppp_ipcp_t *ipcp)
 {
-	struct ipaddr_option_t *ipaddr_opt=_malloc(sizeof(*ipaddr_opt));
-	memset(ipaddr_opt,0,sizeof(*ipaddr_opt));
-	ipaddr_opt->opt.id=CI_ADDR;
-	ipaddr_opt->opt.len=6;
+	struct ipaddr_option_t *ipaddr_opt = _malloc(sizeof(*ipaddr_opt));
+	memset(ipaddr_opt, 0, sizeof(*ipaddr_opt));
+	ipaddr_opt->opt.id = CI_ADDR;
+	ipaddr_opt->opt.len = 6;
+	ipaddr_opt->ppp = ipcp->ppp;
 
 	return &ipaddr_opt->opt;
 }
 
 static void ipaddr_free(struct ppp_ipcp_t *ipcp, struct ipcp_option_t *opt)
 {
-	struct ipaddr_option_t *ipaddr_opt=container_of(opt,typeof(*ipaddr_opt),opt);
+	struct ipaddr_option_t *ipaddr_opt = container_of(opt, typeof(*ipaddr_opt), opt);
 
-	if (ipaddr_opt->ip)
-		ipdb_put_ipv4(ipcp->ppp, ipaddr_opt->ip);
+	if (ipcp->ppp->ipv4)
+		ipdb_put_ipv4(ipcp->ppp, ipcp->ppp->ipv4);
 
 	_free(ipaddr_opt);
 }
@@ -71,8 +71,8 @@ static int check_exists(struct ppp_t *self_ppp, in_addr_t addr)
 
 	pthread_rwlock_rdlock(&ppp_lock);
 	list_for_each_entry(ppp, &ppp_list, entry) {
-		if (!ppp->terminating && ppp->peer_ipaddr == addr && ppp != self_ppp) {
-			log_ppp_warn("ppp:ipcp: requested IP already assigned to %s\n", ppp->ifname);
+		if (!ppp->terminating && ppp->ipv4 && ppp->ipv4->peer_addr == addr && ppp != self_ppp) {
+			log_ppp_warn("ppp: requested IPv4 address already assigned to %s\n", ppp->ifname);
 			r = 1;
 			break;
 		}
@@ -84,74 +84,63 @@ static int check_exists(struct ppp_t *self_ppp, in_addr_t addr)
 
 static int ipaddr_send_conf_req(struct ppp_ipcp_t *ipcp, struct ipcp_option_t *opt, uint8_t *ptr)
 {
-	struct ipaddr_option_t *ipaddr_opt=container_of(opt,typeof(*ipaddr_opt),opt);
-	struct ipcp_opt32_t *opt32=(struct ipcp_opt32_t*)ptr;
+	struct ipaddr_option_t *ipaddr_opt = container_of(opt, typeof(*ipaddr_opt), opt);
+	struct ipcp_opt32_t *opt32 = (struct ipcp_opt32_t *)ptr;
 	
-	if (!ipaddr_opt->ip) {
-		ipaddr_opt->ip = ipdb_get_ipv4(ipcp->ppp);
-		if (!ipaddr_opt->ip) {
-			log_ppp_warn("ppp:ipcp: no free IP address\n");
+	if (!ipcp->ppp->ipv4) {
+		ipcp->ppp->ipv4 = ipdb_get_ipv4(ipcp->ppp);
+		if (!ipcp->ppp->ipv4) {
+			log_ppp_warn("ppp: no free IPv4 address\n");
 			return -1;
 		}
 	}
 	
-	if (iprange_tunnel_check(ipaddr_opt->ip->peer_addr)) {
+	if (iprange_tunnel_check(ipcp->ppp->ipv4->peer_addr)) {
 		log_ppp_warn("ppp:ipcp: to avoid kernel soft lockup requested IP cannot be assigned (%i.%i.%i.%i)\n",
-			ipaddr_opt->ip->peer_addr&0xff, 
-			(ipaddr_opt->ip->peer_addr >> 8)&0xff, 
-			(ipaddr_opt->ip->peer_addr >> 16)&0xff, 
-			(ipaddr_opt->ip->peer_addr >> 24)&0xff);
+			ipcp->ppp->ipv4->peer_addr&0xff, 
+			(ipcp->ppp->ipv4->peer_addr >> 8)&0xff, 
+			(ipcp->ppp->ipv4->peer_addr >> 16)&0xff, 
+			(ipcp->ppp->ipv4->peer_addr >> 24)&0xff);
 		return -1;
 	}
 	
-	if (conf_check_exists && check_exists(ipcp->ppp, ipaddr_opt->ip->peer_addr))
+	if (conf_check_exists && check_exists(ipcp->ppp, ipcp->ppp->ipv4->peer_addr))
 		return -1;
 	
-	ipcp->ppp->ipaddr = ipaddr_opt->ip->addr;
-	ipcp->ppp->peer_ipaddr = ipaddr_opt->ip->peer_addr;
-	
-	opt32->hdr.id=CI_ADDR;
-	opt32->hdr.len=6;
-	opt32->val=ipaddr_opt->ip->addr;
+	opt32->hdr.id = CI_ADDR;
+	opt32->hdr.len = 6;
+	opt32->val = ipcp->ppp->ipv4->addr;
 	return 6;
 }
 
 static int ipaddr_send_conf_nak(struct ppp_ipcp_t *ipcp, struct ipcp_option_t *opt, uint8_t *ptr)
 {
-	struct ipaddr_option_t *ipaddr_opt=container_of(opt,typeof(*ipaddr_opt),opt);
-	struct ipcp_opt32_t *opt32=(struct ipcp_opt32_t*)ptr;
-	opt32->hdr.id=CI_ADDR;
-	opt32->hdr.len=6;
-	opt32->val=ipaddr_opt->ip->peer_addr;
+	struct ipaddr_option_t *ipaddr_opt = container_of(opt, typeof(*ipaddr_opt), opt);
+	struct ipcp_opt32_t *opt32 = (struct ipcp_opt32_t *)ptr;
+	opt32->hdr.id = CI_ADDR;
+	opt32->hdr.len = 6;
+	opt32->val = ipcp->ppp->ipv4->peer_addr;
 	return 6;
 }
 
 static int ipaddr_recv_conf_req(struct ppp_ipcp_t *ipcp, struct ipcp_option_t *opt, uint8_t *ptr)
 {
-	struct ipaddr_option_t *ipaddr_opt = container_of(opt,typeof(*ipaddr_opt), opt);
-	struct ipcp_opt32_t *opt32 = (struct ipcp_opt32_t*)ptr;
+	struct ipaddr_option_t *ipaddr_opt = container_of(opt, typeof(*ipaddr_opt), opt);
+	struct ipcp_opt32_t *opt32 = (struct ipcp_opt32_t *)ptr;
 
 	if (opt32->hdr.len != 6)
 		return IPCP_OPT_REJ;
 
-	if (ipaddr_opt->ip->peer_addr == opt32->val) {
-		//ipcp->ppp->ipaddr = ipaddr_opt->ip->addr;
-		//ipcp->ppp->peer_ipaddr = ipaddr_opt->ip->peer_addr;
+	if (ipcp->ppp->ipv4->peer_addr == opt32->val) {
 		ipcp->delay_ack = ccp_ipcp_started(ipcp->ppp);
 		return IPCP_OPT_ACK;
 	}
 		
-	/*if (!ipaddr_opt->peer_addr) {
-		ipaddr_opt->peer_addr = opt32->val;
-		goto ack;
-	}*/
-	
 	return IPCP_OPT_NAK;
 }
 
 static void if_up(struct ppp_t *ppp)
 {
-	struct ipaddr_option_t *ipaddr_opt = container_of(ipcp_find_option(ppp, &ipaddr_opt_hnd), typeof(*ipaddr_opt), opt);
 	struct ifreq ifr;
 	struct sockaddr_in addr;
 	struct npioctl np;
@@ -162,13 +151,13 @@ static void if_up(struct ppp_t *ppp)
 	strcpy(ifr.ifr_name, ppp->ifname);
 
 	addr.sin_family = AF_INET;
-  addr.sin_addr.s_addr = ipaddr_opt->ip->addr;
+  addr.sin_addr.s_addr = ppp->ipv4->addr;
 	memcpy(&ifr.ifr_addr,&addr,sizeof(addr));
 
 	if (ioctl(sock_fd, SIOCSIFADDR, &ifr))
 		log_ppp_error("ipcp: failed to set PA address: %s\n", strerror(errno));
 	
-  addr.sin_addr.s_addr = ipaddr_opt->ip->peer_addr;
+  addr.sin_addr.s_addr = ppp->ipv4->peer_addr;
 	memcpy(&ifr.ifr_dstaddr,&addr,sizeof(addr));
 	
 	if (ioctl(sock_fd, SIOCSIFDSTADDR, &ifr))
@@ -205,8 +194,8 @@ static void ipaddr_print(void (*print)(const char *fmt,...),struct ipcp_option_t
 
 	if (ptr)
 		in.s_addr = opt32->val;
-	else if (ipaddr_opt->ip)
-		in.s_addr = ipaddr_opt->ip->addr;
+	else if (ipaddr_opt->ppp->ipv4)
+		in.s_addr = ipaddr_opt->ppp->ipv4->addr;
 	
 	print("<addr %s>",inet_ntoa(in));
 }
@@ -229,3 +218,4 @@ static void ipaddr_opt_init()
 }
 
 DEFINE_INIT(4, ipaddr_opt_init);
+
diff --git a/accel-pppd/ppp/ipv6_nd.c b/accel-pppd/ppp/ipv6_nd.c
index bec0ea3..e0ec842 100644
--- a/accel-pppd/ppp/ipv6_nd.c
+++ b/accel-pppd/ppp/ipv6_nd.c
@@ -7,18 +7,50 @@
 #include <pthread.h>
 #include <netinet/in.h>
 #include <netinet/icmp6.h>
+#include <arpa/inet.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 
 #include "log.h"
 #include "ppp.h"
 #include "events.h"
+#include "mempool.h"
+#include "ipdb.h"
 
 #include "memdebug.h"
 
+#define MAX_DNS_COUNT 3
+
 static int conf_init_ra = 3;
 static int conf_init_ra_interval = 1;
 static int conf_ra_interval = 60;
+static int conf_router_lifetime = 300;
+static int conf_rdnss_lifetime = 300;
+static struct in6_addr conf_dns[MAX_DNS_COUNT];
+static int conf_dns_count;
+
+#undef ND_OPT_ROUTE_INFORMATION
+#define  ND_OPT_ROUTE_INFORMATION	24
+struct nd_opt_route_info_local     /* route information */
+{
+	uint8_t   nd_opt_ri_type;
+	uint8_t   nd_opt_ri_len;
+	uint8_t   nd_opt_ri_prefix_len;
+	uint8_t   nd_opt_ri_flags_reserved;
+	uint32_t  nd_opt_ri_lifetime;
+	struct in6_addr  nd_opt_ri_prefix;
+};
+
+#undef ND_OPT_RDNSS_INFORMATION
+#define  ND_OPT_RDNSS_INFORMATION	25
+struct nd_opt_rdnss_info_local
+{
+	uint8_t  nd_opt_rdnssi_type;
+	uint8_t  nd_opt_rdnssi_len;
+	uint16_t nd_opt_rdnssi_pref_flag_reserved;
+	uint32_t nd_opt_rdnssi_lifetime;
+	struct in6_addr  nd_opt_rdnssi[0];
+};
 
 struct ipv6_nd_handler_t
 {
@@ -32,84 +64,112 @@ struct ipv6_nd_handler_t
 static void *pd_key;
 
 #define BUF_SIZE 1024
+static mempool_t buf_pool;
 
-static void ipv6_nd_send_ra(struct ipv6_nd_handler_t *h)
+static void ipv6_nd_send_ra(struct ipv6_nd_handler_t *h, struct sockaddr_in6 *addr)
 {
-	void *buf = _malloc(BUF_SIZE);
+	void *buf = mempool_alloc(buf_pool), *endptr;
 	struct nd_router_advert *adv = buf;
 	struct nd_opt_prefix_info *pinfo;
-	//struct nd_opt_route_info *rinfo;
-	//struct nd_opt_rdnss_info_local *rdnssinfo;
+	struct nd_opt_route_info_local *rinfo;
+	struct nd_opt_rdnss_info_local *rdnssinfo;
+	struct in6_addr *rdnss_addr;
 	//struct nd_opt_mtu *mtu;
-	struct sockaddr_in6 addr;
+	struct ipv6db_addr_t *a;
+	int i;
+	
+	if (!buf) {
+		log_emerg("out of memory\n");
+		return;
+	}
 
 	memset(adv, 0, sizeof(*adv));
 	adv->nd_ra_type = ND_ROUTER_ADVERT;
 	adv->nd_ra_curhoplimit = 64;
-	adv->nd_ra_router_lifetime = htons(1);
+	adv->nd_ra_router_lifetime = htons(conf_router_lifetime);
 	//adv->nd_ra_reachable = 0;
 	//adv->nd_ra_retransmit = 0;
 	
 	pinfo = (struct nd_opt_prefix_info *)(adv + 1);
-	memset(pinfo, 0, sizeof(*pinfo));
-	pinfo->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
-	pinfo->nd_opt_pi_len = 4;
-	pinfo->nd_opt_pi_prefix_len = h->ppp->ipv6_prefix_len;
-	pinfo->nd_opt_pi_flags_reserved = ND_OPT_PI_FLAG_ONLINK | ND_OPT_PI_FLAG_AUTO;
-	pinfo->nd_opt_pi_valid_time = 0xffffffff;
-	pinfo->nd_opt_pi_preferred_time = 0xffffffff;
-	memcpy(&pinfo->nd_opt_pi_prefix, &h->ppp->ipv6_addr, 8);
+	list_for_each_entry(a, &h->ppp->ipv6->addr_list, entry) {
+		memset(pinfo, 0, sizeof(*pinfo));
+		pinfo->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
+		pinfo->nd_opt_pi_len = 4;
+		pinfo->nd_opt_pi_prefix_len = a->prefix_len;
+		pinfo->nd_opt_pi_flags_reserved = ND_OPT_PI_FLAG_ONLINK | ND_OPT_PI_FLAG_AUTO;
+		pinfo->nd_opt_pi_valid_time = 0xffffffff;
+		pinfo->nd_opt_pi_preferred_time = 0xffffffff;
+		memcpy(&pinfo->nd_opt_pi_prefix, &a->addr, 8);
+		pinfo++;
+	}
+	
+	rinfo = (struct nd_opt_route_info_local *)pinfo;
+	list_for_each_entry(a, &h->ppp->ipv6->route_list, entry) {
+		memset(rinfo, 0, sizeof(*rinfo));
+		rinfo->nd_opt_ri_type = ND_OPT_ROUTE_INFORMATION;
+		rinfo->nd_opt_ri_len = 3;
+		rinfo->nd_opt_ri_prefix_len = a->prefix_len;
+		rinfo->nd_opt_ri_lifetime = 0xffffffff;
+		memcpy(&rinfo->nd_opt_ri_prefix, &a->addr, 8);
+		rinfo++;
+	}
+
+	if (conf_dns_count) {
+		rdnssinfo = (struct nd_opt_rdnss_info_local *)rinfo;
+		memset(rdnssinfo, 0, sizeof(*rdnssinfo));
+		rdnssinfo->nd_opt_rdnssi_type = ND_OPT_RDNSS_INFORMATION;
+		rdnssinfo->nd_opt_rdnssi_len = 1 + 2 * conf_dns_count;
+		rdnssinfo->nd_opt_rdnssi_lifetime = htonl(conf_rdnss_lifetime);
+		rdnss_addr = (struct in6_addr *)rdnssinfo->nd_opt_rdnssi;
+		for (i = 0; i < conf_dns_count; i++) {
+			memcpy(rdnss_addr, &conf_dns[i], sizeof(*rdnss_addr));
+			rdnss_addr++;
+		}
+	} else
+		rdnss_addr = (struct in6_addr *)rinfo;
+
+	endptr = rdnss_addr;
 
-	memset(&addr, 0, sizeof(addr));
-	addr.sin6_family = AF_INET6;
-	addr.sin6_addr.s6_addr32[0] = htonl(0xff020000);
-	addr.sin6_addr.s6_addr32[3] = htonl(0x1);
-	addr.sin6_scope_id = h->ppp->ifindex; 
 
-	sendto(h->hnd.fd, buf, (void *)(pinfo + 1) - buf, 0, (struct sockaddr *)&addr, sizeof(addr));
+	sendto(h->hnd.fd, buf, endptr - buf, 0, (struct sockaddr *)addr, sizeof(*addr));
 
-	_free(buf);
+	mempool_free(buf);
 }
 
 static void send_ra_timer(struct triton_timer_t *t)
 {
 	struct ipv6_nd_handler_t *h = container_of(t, typeof(*h), timer);
+	struct sockaddr_in6 addr;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sin6_family = AF_INET6;
+	addr.sin6_addr.s6_addr32[0] = htonl(0xff020000);
+	addr.sin6_addr.s6_addr32[3] = htonl(0x1);
+	addr.sin6_scope_id = h->ppp->ifindex; 
 
 	if (h->ra_sent++ == conf_init_ra) {
 		h->timer.period = conf_ra_interval * 1000;
 		triton_timer_mod(t, 0);
 	}
 
-	ipv6_nd_send_ra(h);
+	ipv6_nd_send_ra(h, &addr);
 }
 
 static int ipv6_nd_read(struct triton_md_handler_t *_h)
 {
 	struct ipv6_nd_handler_t *h = container_of(_h, typeof(*h), hnd);
-	struct msghdr mhdr;
-	int chdr_len;
-	struct iovec iov;
-	struct cmsghdr *chdr, *cmsg;
-	struct in6_pktinfo *pkt_info;
-	struct icmp6_hdr *icmph;
-	void *buf;
+	struct icmp6_hdr *icmph = mempool_alloc(buf_pool);
 	int n;
+	struct sockaddr_in6 addr;
+	socklen_t addr_len = sizeof(addr);
 
-	chdr_len = CMSG_SPACE(sizeof(struct in6_pktinfo)) + CMSG_SPACE(sizeof(int));
-	chdr = _malloc(chdr_len);
-	buf = _malloc(BUF_SIZE);
-
-	iov.iov_len = BUF_SIZE;
-	iov.iov_base = buf;
-
-	memset(&mhdr, 0, sizeof(mhdr));
-	mhdr.msg_iov = &iov;
-	mhdr.msg_iovlen = 1;
-	mhdr.msg_control = chdr;
-	mhdr.msg_controllen = chdr_len;
+	if (!icmph) {
+		log_emerg("out of memory\n");
+		return 0;
+	}
 
 	while (1) {
-		n = recvmsg(h->hnd.fd, &mhdr, 0);
+		n = recvfrom(h->hnd.fd, icmph, BUF_SIZE, 0, &addr, &addr_len);
 		if (n == -1) {
 			if (errno == EAGAIN)
 				break;
@@ -117,50 +177,30 @@ static int ipv6_nd_read(struct triton_md_handler_t *_h)
 			continue;
 		}
 
-		pkt_info = NULL;
-		for (cmsg = CMSG_FIRSTHDR(&mhdr); cmsg != NULL; cmsg = CMSG_NXTHDR(&mhdr, cmsg)) {
-			if (cmsg->cmsg_level == IPPROTO_IPV6 &&
-				  cmsg->cmsg_type == IPV6_PKTINFO) {
-				if (cmsg->cmsg_len != CMSG_LEN(sizeof(*pkt_info)))
-					log_ppp_warn("ipv6_nd: received invalid IPV6_PKTINFO\n");
-				else
-					pkt_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
-				break;
-			}
-		}
-
-		if (!pkt_info) {
-			log_ppp_warn("ipv6_nd: no IPV6_PKTINFO\n");
-			continue;
-		}
-
 		if (n < sizeof(*icmph)) {
 			log_ppp_warn("ipv6_nd: received short icmp packet (%i)\n", n);
 			continue;
 		}
 
-		icmph = buf;
-
 		if (icmph->icmp6_type != ND_ROUTER_SOLICIT) {
 			log_ppp_warn("ipv6_nd: received unexcpected icmp packet (%i)\n", icmph->icmp6_type);
 			continue;
 		}
 
-		/*if (!IN6_IS_ADDR_LINKLOCAL(&pkt_info->ipi6_addr)) {
+		if (!IN6_IS_ADDR_LINKLOCAL(&addr.sin6_addr)) {
 			log_ppp_warn("ipv6_nd: received icmp packet from non link-local address\n");
 			continue;
-		}*/
+		}
 
-		/*if (*(uint64_t *)(pkt_info->ipi6_addr.s6_addr + 8) != *(uint64_t *)(h->ppp->ipv6_addr.s6_addr + 8)) {
+		/*if (*(uint64_t *)(addr.sin6_addr.s6_addr + 8) != *(uint64_t *)(h->ppp->ipv6_addr.s6_addr + 8)) {
 			log_ppp_warn("ipv6_nd: received icmp packet from unknown address\n");
 			continue;
 		}*/
 
-		ipv6_nd_send_ra(h);
+		ipv6_nd_send_ra(h, &addr);
 	}
 
-	_free(chdr);
-	_free(buf);
+	mempool_free(icmph);
 
 	return 0;
 }
@@ -192,12 +232,6 @@ int ppp_ipv6_nd_start(struct ppp_t *ppp, uint64_t intf_id)
 		goto out_err;
 	}
 
-	val = 1;
-	if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val))) {
-		log_ppp_error("ipv6_nd: setsockopt(IPV6_PKTINFO): %s\n", strerror(errno));
-		goto out_err;
-	}
-
 	val = 2;
 	if (setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val))) {
 		log_ppp_error("ipv6_nd: setsockopt(IPV6_CHECKSUM): %s\n", strerror(errno));
@@ -299,10 +333,35 @@ static void ev_ppp_finishing(struct ppp_t *ppp)
 	_free(h);
 }
 
+static void load_config(void)
+{
+	struct conf_sect_t *s = conf_get_section("dnsv6");
+	struct conf_option_t *opt;
+	
+	if (!s)
+		return;
+	
+	conf_dns_count = 0;
+
+	list_for_each_entry(opt, &s->items, entry) {
+		if (inet_pton(AF_INET6, opt->name, &conf_dns[conf_dns_count]) == 0) {
+			log_error("dnsv6: faild to parse '%s'\n", opt->name);
+			continue;
+		}
+		if (++conf_dns_count == MAX_DNS_COUNT)
+			break;
+	}
+}
+
 static void init(void)
 {
+	buf_pool = mempool_create(BUF_SIZE);
+
+	load_config();
+
+	triton_event_register_handler(EV_CONFIG_RELOAD, (triton_event_func)load_config);
 	triton_event_register_handler(EV_PPP_STARTED, (triton_event_func)ev_ppp_started);
 	triton_event_register_handler(EV_PPP_FINISHING, (triton_event_func)ev_ppp_finishing);
 }
 
-DEFINE_INIT(0, init);
+DEFINE_INIT(5, init);
diff --git a/accel-pppd/ppp/ipv6cp_opt_intfid.c b/accel-pppd/ppp/ipv6cp_opt_intfid.c
index b55d3ff..9a9b9e3 100644
--- a/accel-pppd/ppp/ipv6cp_opt_intfid.c
+++ b/accel-pppd/ppp/ipv6cp_opt_intfid.c
@@ -45,7 +45,6 @@ struct ipaddr_option_t
 {
 	struct ipv6cp_option_t opt;
 	uint64_t intf_id;
-	struct ipv6db_item_t *ip;
 	int started:1;
 };
 
@@ -87,25 +86,33 @@ static void ipaddr_free(struct ppp_ipv6cp_t *ipv6cp, struct ipv6cp_option_t *opt
 	_free(ipaddr_opt);
 }
 
-static int check_exists(struct ppp_t *self_ppp, struct in6_addr *addr)
+static int check_exists(struct ppp_t *self_ppp)
 {
 	struct ppp_t *ppp;
+	struct ipv6db_addr_t *a1, *a2;
 	int r = 0;
 
 	pthread_rwlock_rdlock(&ppp_lock);
 	list_for_each_entry(ppp, &ppp_list, entry) {
 		if (ppp->terminating)
 			continue;
+		if (!ppp->ipv6)
+			continue;
 		if (ppp == self_ppp)
 			continue;
 
-		if (addr->s6_addr32[0] == ppp->ipv6_addr.s6_addr32[0] &&
-			  addr->s6_addr32[1] == ppp->ipv6_addr.s6_addr32[1]) {
-			log_ppp_warn("ppp:ipv6cp: requested IP already assigned to %s\n", ppp->ifname);
-			r = 1;
-			break;
+		list_for_each_entry(a1, &ppp->ipv6->addr_list, entry) {
+			list_for_each_entry(a2, &self_ppp->ipv6->addr_list, entry) {
+				if (a1->addr.s6_addr32[0] == a2->addr.s6_addr32[0] &&
+						a1->addr.s6_addr32[1] == a2->addr.s6_addr32[1]) {
+					log_ppp_warn("ppp: requested IPv6 address already assigned to %s\n", ppp->ifname);
+					r = 1;
+					goto out;
+				}
+			}
 		}
 	}
+out:
 	pthread_rwlock_unlock(&ppp_lock);
 
 	return r;
@@ -116,20 +123,17 @@ static int ipaddr_send_conf_req(struct ppp_ipv6cp_t *ipv6cp, struct ipv6cp_optio
 	struct ipaddr_option_t *ipaddr_opt = container_of(opt, typeof(*ipaddr_opt), opt);
 	struct ipv6cp_opt64_t *opt64 = (struct ipv6cp_opt64_t *)ptr;
 	
-	if (!ipaddr_opt->ip) {
-		ipaddr_opt->ip = ipdb_get_ipv6(ipv6cp->ppp);
-		if (!ipaddr_opt->ip) {
-			log_ppp_warn("ppp:ipv6cp: no free IP address\n");
+	if (!ipv6cp->ppp->ipv6) {
+		ipv6cp->ppp->ipv6 = ipdb_get_ipv6(ipv6cp->ppp);
+		if (!ipv6cp->ppp->ipv6) {
+			log_ppp_warn("ppp: no free IPv6 address\n");
 			return -1;
 		}
 	}
 	
-	if (conf_check_exists && check_exists(ipv6cp->ppp, &ipaddr_opt->ip->addr))
+	if (conf_check_exists && check_exists(ipv6cp->ppp))
 		return -1;
 	
-	ipv6cp->ppp->ipv6_addr = ipaddr_opt->ip->addr;
-	ipv6cp->ppp->ipv6_prefix_len = ipaddr_opt->ip->prefix_len;
-	
 	opt64->hdr.id = CI_INTFID;
 	opt64->hdr.len = 10;
 	opt64->val = ipaddr_opt->intf_id;
@@ -142,7 +146,7 @@ static int ipaddr_send_conf_nak(struct ppp_ipv6cp_t *ipv6cp, struct ipv6cp_optio
 	struct ipv6cp_opt64_t *opt64 = (struct ipv6cp_opt64_t *)ptr;
 	opt64->hdr.id = CI_INTFID;
 	opt64->hdr.len = 10;
-	opt64->val = *(uint64_t *)(&ipaddr_opt->ip->addr.s6_addr32[2]);
+	opt64->val = ipv6cp->ppp->ipv6->intf_id;
 	return 10;
 }
 
@@ -151,11 +155,12 @@ static int ipaddr_recv_conf_req(struct ppp_ipv6cp_t *ipv6cp, struct ipv6cp_optio
 	struct ipaddr_option_t *ipaddr_opt = container_of(opt, typeof(*ipaddr_opt), opt);
 	struct ipv6cp_opt64_t *opt64 = (struct ipv6cp_opt64_t* )ptr;
 	struct in6_ifreq ifr6;
+	struct ipv6db_addr_t *a;
 
 	if (opt64->hdr.len != 10)
 		return IPV6CP_OPT_REJ;
 
-	if (*(uint64_t *)(&ipaddr_opt->ip->addr.s6_addr32[2]) == opt64->val)
+	if (ipv6cp->ppp->ipv6->intf_id == opt64->val)
 		goto ack;
 		
 	return IPV6CP_OPT_NAK;
@@ -188,11 +193,13 @@ ack:
 		return IPV6CP_OPT_REJ;
 	}
 
-	memcpy(ifr6.ifr6_addr.s6_addr, ipaddr_opt->ip->addr.s6_addr, 8);
+	list_for_each_entry(a, &ipv6cp->ppp->ipv6->addr_list, entry) {
+		memcpy(ifr6.ifr6_addr.s6_addr, a->addr.s6_addr, 8);
 
-	if (ioctl(sock6_fd, SIOCSIFADDR, &ifr6)) {
-		log_ppp_error("ppp:ipv6cp: ioctl(SIOCSIFADDR): %s\n", strerror(errno));
-		return IPV6CP_OPT_REJ;
+		if (ioctl(sock6_fd, SIOCSIFADDR, &ifr6)) {
+			log_ppp_error("ppp:ipv6cp: ioctl(SIOCSIFADDR): %s\n", strerror(errno));
+			return IPV6CP_OPT_REJ;
+		}
 	}
 
 	if (ppp_ipv6_nd_start(ipv6cp->ppp, ipaddr_opt->intf_id))
diff --git a/accel-pppd/ppp/ppp.h b/accel-pppd/ppp/ppp.h
index 4708578..f95893a 100644
--- a/accel-pppd/ppp/ppp.h
+++ b/accel-pppd/ppp/ppp.h
@@ -62,6 +62,9 @@
 
 struct ppp_t;
 
+struct ipv4db_item_t;
+struct ipv6db_item_t;
+
 struct ppp_ctrl_t
 {
 	struct triton_context_t *ctx;
@@ -100,10 +103,8 @@ struct ppp_t
 	time_t start_time;
 	time_t stop_time;
 	char *username;
-	in_addr_t ipaddr;
-	in_addr_t peer_ipaddr;
-	struct in6_addr ipv6_addr;
-	int ipv6_prefix_len;
+	struct ipv4db_item_t *ipv4;
+	struct ipv6db_item_t *ipv6;
 
 	struct ppp_ctrl_t *ctrl;
 
diff --git a/accel-pppd/radius/radius.c b/accel-pppd/radius/radius.c
index ae5948b..4200d62 100644
--- a/accel-pppd/radius/radius.c
+++ b/accel-pppd/radius/radius.c
@@ -174,7 +174,7 @@ static struct ipv4db_item_t *get_ipv4(struct ppp_t *ppp)
 
 static struct ipv6db_item_t *get_ipv6(struct ppp_t *ppp)
 {
-	struct radius_pd_t *rpd = find_pd(ppp);
+	//struct radius_pd_t *rpd = find_pd(ppp);
 	
 	//if (memcmp(&rpd->ipv6_addr.peer_addr, &in6addr_any, sizeof(in6addr_any)))
 	//	return &rpd->ipv6_addr;
@@ -302,7 +302,7 @@ struct radius_pd_t *rad_find_session(const char *sessionid, const char *username
 			continue;
 		if (port_id >= 0 && port_id != rpd->ppp->unit_idx)
 			continue;
-		if (ipaddr && ipaddr != rpd->ppp->peer_ipaddr)
+		if (ipaddr && rpd->ppp->ipv4 && ipaddr != rpd->ppp->ipv4->peer_addr)
 			continue;
 		if (csid && rpd->ppp->ctrl->calling_station_id && strcmp(csid, rpd->ppp->ctrl->calling_station_id))
 			continue;
diff --git a/accel-pppd/radius/req.c b/accel-pppd/radius/req.c
index b45a601..462e656 100644
--- a/accel-pppd/radius/req.c
+++ b/accel-pppd/radius/req.c
@@ -130,8 +130,10 @@ int rad_req_acct_fill(struct rad_req_t *req)
 		if (rad_packet_add_int(req->pack, NULL, "Acct-Delay-Time", 0))
 			return -1;
 	}
-	if (rad_packet_add_ipaddr(req->pack, NULL, "Framed-IP-Address", req->rpd->ppp->peer_ipaddr))
-		return -1;
+	if (req->rpd->ppp->ipv4) {
+		if (rad_packet_add_ipaddr(req->pack, NULL, "Framed-IP-Address", req->rpd->ppp->ipv4->peer_addr))
+			return -1;
+	}
 
 	return 0;
 }
diff --git a/rfc/rfc5006.txt b/rfc/rfc5006.txt
new file mode 100644
index 0000000..056f149
--- /dev/null
+++ b/rfc/rfc5006.txt
@@ -0,0 +1,675 @@
+
+
+
+
+
+
+Network Working Group                                      J. Jeong, Ed.
+Request for Comments: 5006                  ETRI/University of Minnesota
+Category: Experimental                                           S. Park
+                                                     SAMSUNG Electronics
+                                                              L. Beloeil
+                                                      France Telecom R&D
+                                                          S. Madanapalli
+                                                      Ordyn Technologies
+                                                          September 2007
+
+
+         IPv6 Router Advertisement Option for DNS Configuration
+
+Status of This Memo
+
+   This memo defines an Experimental Protocol for the Internet
+   community.  It does not specify an Internet standard of any kind.
+   Discussion and suggestions for improvement are requested.
+   Distribution of this memo is unlimited.
+
+Abstract
+
+   This document specifies a new IPv6 Router Advertisement option to
+   allow IPv6 routers to advertise DNS recursive server addresses to
+   IPv6 hosts.
+
+Table of Contents
+
+   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
+     1.1.  Applicability Statements . . . . . . . . . . . . . . . . .  2
+     1.2.  Coexistence of RDNSS Option and DHCP Option  . . . . . . .  2
+   2.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   4.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   5.  Neighbor Discovery Extension . . . . . . . . . . . . . . . . .  4
+     5.1.  Recursive DNS Server Option  . . . . . . . . . . . . . . .  4
+     5.2.  Procedure of DNS Configuration . . . . . . . . . . . . . .  5
+       5.2.1.  Procedure in IPv6 Host . . . . . . . . . . . . . . . .  5
+   6.  Implementation Considerations  . . . . . . . . . . . . . . . .  6
+     6.1.  DNS Server List Management . . . . . . . . . . . . . . . .  6
+     6.2.  Synchronization between DNS Server List and Resolver
+           Repository . . . . . . . . . . . . . . . . . . . . . . . .  7
+   7.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
+   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
+   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  8
+   10. References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
+     10.1. Normative References . . . . . . . . . . . . . . . . . . .  9
+     10.2. Informative References . . . . . . . . . . . . . . . . . .  9
+
+
+
+Jeong, et al.                 Experimental                      [Page 1]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+1.  Introduction
+
+   Neighbor Discovery (ND) for IP Version 6 and IPv6 Stateless Address
+   Autoconfiguration provide ways to configure either fixed or mobile
+   nodes with one or more IPv6 addresses, default routers and some other
+   parameters [2][3].  To support the access to additional services in
+   the Internet that are identified by a DNS name, such as a web server,
+   the configuration of at least one recursive DNS server is also needed
+   for DNS name resolution.
+
+   It is infeasible for nomadic hosts, such as laptops, to be configured
+   manually with a DNS resolver each time they connect to a different
+   wireless LAN (WLAN) such as IEEE 802.11 a/b/g [12]-[15].  Normally,
+   DHCP [6]-[8] is used to locate such resolvers.  This document
+   provides an alternate, experimental mechanism which uses a new IPv6
+   Router Advertisement (RA) option to allow IPv6 routers to advertise
+   DNS recursive server addresses to IPv6 hosts.
+
+1.1.  Applicability Statements
+
+   The only standards-track DNS configuration mechanism in the IETF is
+   DHCP, and its support in hosts and routers is necessary for reasons
+   of interoperability.
+
+   RA-based DNS configuration is a useful, optional alternative in
+   networks where an IPv6 host's address is autoconfigured through IPv6
+   stateless address autoconfiguration, and where the delays in
+   acquiring server addresses and communicating with the servers are
+   critical.  RA-based DNS configuration allows the host to acquire the
+   nearest server addresses on every link.  Furthermore, it learns these
+   addresses from the same RA message that provides configuration
+   information for the link, thereby avoiding an additional protocol
+   run.  This can be beneficial in some mobile environments, such as
+   with Mobile IPv6 [10].
+
+   The advantages and disadvantages of the RA-based approach are
+   discussed in [9] along with other approaches, such as the DHCP and
+   well-known anycast addresses approaches.
+
+1.2.  Coexistence of RDNSS Option and DHCP Option
+
+   The RDNSS (Recursive DNS Server) option and DHCP option can be used
+   together [9].  To order the RA and DHCP approaches, the O (Other
+   stateful configuration) flag can be used in the RA message [2].  If
+   no RDNSS option is included in the RA messages, an IPv6 host may
+   perform DNS configuration through DHCPv6 [6]-[8] regardless of
+   whether the O flag is set or not.
+
+
+
+
+Jeong, et al.                 Experimental                      [Page 2]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+2.  Definitions
+
+   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+   document are to be interpreted as described in [1].
+
+3.  Terminology
+
+   This document uses the terminology described in [2] and [3].  In
+   addition, four new terms are defined below:
+
+   o  Recursive DNS Server (RDNSS): Server which provides a recursive
+      DNS resolution service for translating domain names into IP
+      addresses as defined in [4] and [5].
+
+   o  RDNSS Option: IPv6 RA option to deliver the RDNSS information to
+      IPv6 hosts [2].
+
+   o  DNS Server List: A data structure for managing DNS Server
+      Information in the IPv6 protocol stack in addition to the Neighbor
+      Cache and Destination Cache for Neighbor Discovery [2].
+
+   o  Resolver Repository: Configuration repository with RDNSS addresses
+      that a DNS resolver on the host uses for DNS name resolution; for
+      example, the Unix resolver file (i.e., /etc/resolv.conf) and
+      Windows registry.
+
+4.  Overview
+
+   This document defines a new ND option called RDNSS option that
+   contains the addresses of recursive DNS servers.  Existing ND
+   transport mechanisms (i.e., advertisements and solicitations) are
+   used.  This works in the same way that hosts learn about routers and
+   prefixes.  An IPv6 host can configure the IPv6 addresses of one or
+   more RDNSSes via RA messages periodically sent by a router or
+   solicited by a Router Solicitation (RS).
+
+   Through the RDNSS option, along with the prefix information option
+   based on the ND protocol ([2] and [3]), an IPv6 host can perform
+   network configuration of its IPv6 address and RDNSS simultaneously
+   without needing a separate message exchange for the RDNSS
+   information.  The RA option for RDNSS can be used on any network that
+   supports the use of ND.
+
+   This approach requires RDNSS information to be configured in the
+   routers sending the advertisements.  The configuration of RDNSS
+   addresses in the routers can be done by manual configuration.  The
+   automatic configuration or redistribution of RDNSS information is
+
+
+
+Jeong, et al.                 Experimental                      [Page 3]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+   possible by running a DHCPv6 client on the router [6]-[8].  The
+   automatic configuration of RDNSS addresses in routers is out of scope
+   for this document.
+
+5.  Neighbor Discovery Extension
+
+   The IPv6 DNS configuration mechanism in this document needs a new ND
+   option in Neighbor Discovery: the Recursive DNS Server (RDNSS)
+   option.
+
+5.1.  Recursive DNS Server Option
+
+   The RDNSS option contains one or more IPv6 addresses of recursive DNS
+   servers.  All of the addresses share the same lifetime value.  If it
+   is desirable to have different lifetime values, multiple RDNSS
+   options can be used.  Figure 1 shows the format of the RDNSS option.
+
+      0                   1                   2                   3
+      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |     Type      |     Length    |           Reserved            |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                           Lifetime                            |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                                                               |
+     :            Addresses of IPv6 Recursive DNS Servers            :
+     |                                                               |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+           Figure 1: Recursive DNS Server (RDNSS) Option Format
+
+   Fields:
+
+     Type          8-bit identifier of the RDNSS option type as assigned
+                   by the IANA: 25
+
+     Length        8-bit unsigned integer.  The length of the option
+                   (including the Type and Length fields) is in units of
+                   8 octets.  The minimum value is 3 if one IPv6 address
+                   is contained in the option.  Every additional RDNSS
+                   address increases the length by 2.  The Length field
+                   is used by the receiver to determine the number of
+                   IPv6 addresses in the option.
+
+
+
+
+
+
+
+
+Jeong, et al.                 Experimental                      [Page 4]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+     Lifetime      32-bit unsigned integer.  The maximum time, in
+                   seconds (relative to the time the packet is sent),
+                   over which this RDNSS address MAY be used for name
+                   resolution.  Hosts MAY send a Router Solicitation to
+                   ensure the RDNSS information is fresh before the
+                   interval expires.  In order to provide fixed hosts
+                   with stable DNS service and allow mobile hosts to
+                   prefer local RDNSSes to remote RDNSSes, the value of
+                   Lifetime should be at least as long as the Maximum RA
+                   Interval (MaxRtrAdvInterval) in RFC 4861, and be at
+                   most as long as two times MaxRtrAdvInterval; Lifetime
+                   SHOULD be bounded as follows:  MaxRtrAdvInterval <=
+                   Lifetime <= 2*MaxRtrAdvInterval.  A value of all one
+                   bits (0xffffffff) represents infinity.  A value of
+                   zero means that the RDNSS address MUST no longer be
+                   used.
+
+     Addresses of IPv6 Recursive DNS Servers
+                   One or more 128-bit IPv6 addresses of the recursive
+                   DNS servers.  The number of addresses is determined
+                   by the Length field.  That is, the number of
+                   addresses is equal to (Length - 1) / 2.
+
+5.2.  Procedure of DNS Configuration
+
+   The procedure of DNS configuration through the RDNSS option is the
+   same as with any other ND option [2].
+
+5.2.1.  Procedure in IPv6 Host
+
+   When an IPv6 host receives an RDNSS option through RA, it checks
+   whether the option is valid.
+
+   o  If the RDNSS option is valid, the host SHOULD copy the option's
+      value into the DNS Server List and the Resolver Repository as long
+      as the value of the Length field is greater than or equal to the
+      minimum value (3).  The host MAY ignore additional RDNSS addresses
+      within an RDNSS option and/or additional RDNSS options within an
+      RA when it has gathered a sufficient number of RDNSS addresses.
+
+   o  If the RDNSS option is invalid (e.g., the Length field has a value
+      less than 3), the host SHOULD discard the option.
+
+
+
+
+
+
+
+
+
+Jeong, et al.                 Experimental                      [Page 5]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+6.  Implementation Considerations
+
+   Note:  This non-normative section gives some hints for implementing
+      the processing of the RDNSS option in an IPv6 host.
+
+   For the configuration and management of RDNSS information, the
+   advertised RDNSS addresses can be stored and managed in both the DNS
+   Server List and the Resolver Repository.
+
+   In environments where the RDNSS information is stored in user space
+   and ND runs in the kernel, it is necessary to synchronize the DNS
+   Server List of RDNSS addresses in kernel space and the Resolver
+   Repository in user space.  For the synchronization, an implementation
+   where ND works in the kernel should provide a write operation for
+   updating RDNSS information from the kernel to the Resolver
+   Repository.  One simple approach is to have a daemon (or a program
+   that is called at defined intervals) that keeps monitoring the
+   lifetime of RDNSS addresses all the time.  Whenever there is an
+   expired entry in the DNS Server List, the daemon can delete the
+   corresponding entry from the Resolver Repository.
+
+6.1.  DNS Server List Management
+
+   The kernel or user-space process (depending on where RAs are
+   processed) should maintain a data structure called a DNS Server List
+   which keeps the list of RDNSS addresses.  Each entry in the DNS
+   Server List consists of an RDNSS address and Expiration-time as
+   follows:
+
+   o  RDNSS address: IPv6 address of the Recursive DNS Server, which is
+      available for recursive DNS resolution service in the network
+      advertising the RDNSS option; such a network is called site in
+      this document.
+
+   o  Expiration-time: The time when this entry becomes invalid.
+      Expiration-time is set to the value of the Lifetime field of the
+      RDNSS option plus the current system time.  Whenever a new RDNSS
+      option with the same address is received, this field is updated to
+      have a new expiration time.  When Expiration-time becomes less
+      than the current system time, this entry is regarded as expired.
+
+   Note:  An RDNSS address MUST be used only as long as both the RA
+      router lifetime and the RDNSS option lifetime have not expired.
+      The reason is that the RDNSS may not be currently reachable or may
+      not provide service to the host's current address (e.g., due to
+      network ingress filtering [16][17]).
+
+
+
+
+
+Jeong, et al.                 Experimental                      [Page 6]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+6.2.  Synchronization between DNS Server List and Resolver Repository
+
+   When an IPv6 host receives the information of multiple RDNSS
+   addresses within a site through an RA message with RDNSS option(s),
+   it stores the RDNSS addresses (in order) into both the DNS Server
+   List and the Resolver Repository.  The processing of the RDNSS
+   option(s) included in an RA message is as follows:
+
+      Step (a): Receive and parse the RDNSS option(s).  For the RDNSS
+      addresses in each RDNSS option, perform Step (b) through Step (d).
+      Note that Step (e) is performed whenever an entry expires in the
+      DNS Server List.
+
+      Step (b): For each RDNSS address, check the following: If the
+      RDNSS address already exists in the DNS Server List and the RDNSS
+      option's Lifetime field is set to zero, delete the corresponding
+      RDNSS entry from both the DNS Server List and the Resolver
+      Repository in order to prevent the RDNSS address from being used
+      any more for certain reasons in network management, e.g., the
+      breakdown of the RDNSS or a renumbering situation.  The processing
+      of this RDNSS address is finished here.  Otherwise, go to Step
+      (c).
+
+      Step (c): For each RDNSS address, if it already exists in the DNS
+      Server List, then just update the value of the Expiration-time
+      field according to the procedure specified in the second bullet of
+      Section 6.1.  Otherwise, go to Step (d).
+
+      Step (d): For each RDNSS address, if it does not exist in the DNS
+      Server List, register the RDNSS address and lifetime with the DNS
+      Server List and then insert the RDNSS address in front of the
+      Resolver Repository.  In the case where the data structure for the
+      DNS Server List is full of RDNSS entries, delete from the DNS
+      Server List the entry with the shortest expiration time (i.e., the
+      entry that will expire first).  The corresponding RDNSS address is
+      also deleted from the Resolver Repository.  In the order in the
+      RDNSS option, position the newly added RDNSS addresses in front of
+      the Resolver Repository so that the new RDNSS addresses may be
+      preferred according to their order in the RDNSS option for the DNS
+      name resolution.  The processing of these RDNSS addresses is
+      finished here.  Note that, in the case where there are several
+      routers advertising RDNSS option(s) in a subnet, the RDNSSes that
+      have been announced recently are preferred.
+
+      Step (e): Delete each expired entry from the DNS Server List, and
+      delete the RDNSS address corresponding to the entry from the
+      Resolver Repository.
+
+
+
+
+Jeong, et al.                 Experimental                      [Page 7]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+7.  Security Considerations
+
+   The security of the RA option for RDNSS might be worse than ND
+   protocol security [2].  However, any new vulnerability in this RA
+   option is not known yet.  In this context, it can be claimed that the
+   vulnerability of ND is not worse and is a subset of the attacks that
+   any node attached to a LAN can do independently of ND.  A malicious
+   node on a LAN can promiscuously receive packets for any router's MAC
+   address and send packets with the router's MAC address as the source
+   MAC address in the L2 header.  As a result, L2 switches send packets
+   addressed to the router to the malicious node.  Also, this attack can
+   send redirects that tell the hosts to send their traffic somewhere
+   else.  The malicious node can send unsolicited RA or Neighbor
+   Advertisement (NA) replies, answer RS or Neighbor Solicitation (NS)
+   requests, etc.  Also, an attacker could configure a host to send out
+   an RA with a fraudulent RDNSS address, which is presumably an easier
+   avenue of attack than becoming a rogue router and having to process
+   all traffic for the subnet.  It is necessary to disable the RA RDNSS
+   option in both routers and clients administratively to avoid this
+   problem.  All of this can be done independently of implementing ND.
+   Therefore, it can be claimed that the RA option for RDNSS has
+   vulnerabilities similar to those existing in current mechanisms.
+
+   If the Secure Neighbor Discovery (SEND) protocol is used as a
+   security mechanism for ND, all the ND options including the RDNSS
+   option are automatically included in the signatures [11], so the
+   RDNSS transport is integrity-protected.  However, since any valid
+   SEND node can still insert RDNSS options, SEND cannot verify who is
+   or is not authorized to send the options.
+
+8.  IANA Considerations
+
+   The IANA has assigned a new IPv6 Neighbor Discovery Option type for
+   the RDNSS option defined in this document.
+
+                 Option Name               Type
+                 RDNSS option              25
+
+   The IANA registry for these options is:
+
+       http://www.iana.org/assignments/icmpv6-parameters
+
+9.  Acknowledgements
+
+   This document has greatly benefited from inputs by Robert Hinden,
+   Pekka Savola, Iljitsch van Beijnum, Brian Haberman and Tim Chown.
+   The authors appreciate their contributions.
+
+
+
+
+Jeong, et al.                 Experimental                      [Page 8]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+10.  References
+
+10.1.  Normative References
+
+   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
+         Levels", BCP 14, RFC 2119, March 1997.
+
+   [2]   Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
+         "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
+         September 2007.
+
+   [3]   Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address
+         Autoconfiguration", RFC 4862, September 2007.
+
+10.2.  Informative References
+
+   [4]   Mockapetris, P., "Domain Names - Concepts and Facilities",
+         RFC 1034, November 1987.
+
+   [5]   Mockapetris, P., "Domain Names - Implementation and
+         Specification", RFC 1035, November 1987.
+
+   [6]   Droms, R., Ed., "Dynamic Host Configuration Protocol for IPv6
+         (DHCPv6)", RFC 3315, July 2003.
+
+   [7]   Droms, R., "Stateless Dynamic Host Configuration Protocol
+         (DHCP) Service for IPv6", RFC 3736, April 2004.
+
+   [8]   Droms, R., Ed., "DNS Configuration options for Dynamic Host
+         Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
+         December 2003.
+
+   [9]   Jeong, J., Ed., "IPv6 Host Configuration of DNS Server
+         Information Approaches", RFC 4339, February 2006.
+
+   [10]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
+         IPv6", RFC 3775, June 2004.
+
+   [11]  Arkko, J., Ed., "SEcure Neighbor Discovery (SEND)", RFC 3971,
+         March 2005.
+
+   [12]  ANSI/IEEE Std 802.11, "Part 11: Wireless LAN Medium Access
+         Control (MAC) and Physical Layer (PHY) Specifications",
+         March 1999.
+
+   [13]  IEEE Std 802.11a, "Part 11: Wireless LAN Medium Access Control
+         (MAC) and Physical Layer (PHY) specifications: High-speed
+         Physical Layer in the 5 GHZ Band", September 1999.
+
+
+
+Jeong, et al.                 Experimental                      [Page 9]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+   [14]  IEEE Std 802.11b, "Part 11: Wireless LAN Medium Access Control
+         (MAC) and Physical Layer (PHY) specifications: Higher-Speed
+         Physical Layer Extension in the 2.4 GHz Band", September 1999.
+
+   [15]  IEEE P802.11g/D8.2, "Part 11: Wireless LAN Medium Access
+         Control (MAC) and Physical Layer (PHY) specifications: Further
+         Higher Data Rate Extension in the 2.4 GHz Band", April 2003.
+
+   [16]  Damas, J. and F. Neves, "Preventing Use of Recursive
+         Nameservers in Reflector Attacks", Work in Progress, July 2007.
+
+   [17]  Ferguson, P. and D. Senie, "Network Ingress Filtering:
+         Defeating Denial of Service Attacks which employ IP Source
+         Address Spoofing", BCP 38, RFC 2827, May 2000.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Jeong, et al.                 Experimental                     [Page 10]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+Authors' Addresses
+
+   Jaehoon Paul Jeong (editor)
+   ETRI/Department of Computer Science and Engineering
+   University of Minnesota
+   117 Pleasant Street SE
+   Minneapolis, MN  55455
+   USA
+
+   Phone: +1 651 587 7774
+   Fax:   +1 612 625 0572
+   EMail: jjeong@cs.umn.edu
+   URI:   http://www.cs.umn.edu/~jjeong/
+
+
+   Soohong Daniel Park
+   Mobile Convergence Laboratory
+   SAMSUNG Electronics
+   416 Maetan-3dong, Yeongtong-Gu
+   Suwon, Gyeonggi-Do  443-742
+   Korea
+
+   Phone: +82 31 200 4508
+   EMail: soohong.park@samsung.com
+
+
+   Luc Beloeil
+   France Telecom R&D
+   42, rue des coutures
+   BP 6243
+   14066 CAEN Cedex 4
+   France
+
+   Phone: +33 02 3175 9391
+   EMail: luc.beloeil@orange-ftgroup.com
+
+
+   Syam Madanapalli
+   Ordyn Technologies
+   1st Floor, Creator Building, ITPL
+   Bangalore - 560066
+   India
+
+   Phone: +91-80-40383000
+   EMail: smadanapalli@gmail.com
+
+
+
+
+
+
+Jeong, et al.                 Experimental                     [Page 11]
+
+RFC 5006          IPv6 RA Option for DNS Configuration    September 2007
+
+
+Full Copyright Statement
+
+   Copyright (C) The IETF Trust (2007).
+
+   This document is subject to the rights, licenses and restrictions
+   contained in BCP 78, and except as set forth therein, the authors
+   retain all their rights.
+
+   This document and the information contained herein are provided on an
+   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
+   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
+   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
+   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
+   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Intellectual Property
+
+   The IETF takes no position regarding the validity or scope of any
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+
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+
+   The IETF invites any interested party to bring to its attention any
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+   ietf-ipr@ietf.org.
+
+
+
+
+
+
+
+
+
+
+
+
+Jeong, et al.                 Experimental                     [Page 12]
+