X-Git-Url: https://git.decadent.org.uk/gitweb/?p=odhcp6c.git;a=blobdiff_plain;f=src%2Fdhcpv6.c;h=f91f2cf16b8c8ff6fe881310433b98b68e2d8780;hp=31a69b64228ff67883d489d2ce27144f1c2f7492;hb=ca0693fe09d59a95192c4ad86492f05dfadbbf10;hpb=0cff1df7566363e869979df49ec17292c2b1b986

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 31a69b6..f91f2cf 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
+ * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License v2 as published by
@@ -23,6 +23,7 @@
 #include <unistd.h>
 #include <syslog.h>
 #include <stdbool.h>
+#include <ctype.h>
 #include <sys/time.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
@@ -42,9 +43,14 @@
 #define DHCPV6_DUID_LLADDR 3
 #define DHCPV6_REQ_DELAY 1
 
+#define DHCPV6_SOL_MAX_RT_MIN 60
+#define DHCPV6_SOL_MAX_RT_MAX 86400
+#define DHCPV6_INF_MAX_RT_MIN 60
+#define DHCPV6_INF_MAX_RT_MAX 86400
 
 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
-		const uint8_t transaction[3], enum dhcpv6_msg type);
+		const uint8_t transaction[3], enum dhcpv6_msg type,
+		const struct in6_addr *daddr);
 
 static int dhcpv6_parse_ia(void *opt, void *end);
 
@@ -57,6 +63,8 @@ static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
 		const void *status_msg, const int len,
 		bool handled_status_codes[_DHCPV6_Status_Max],
 		int *ret);
+static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
+static void dhcpv6_clear_all_server_cand(void);
 
 static reply_handler dhcpv6_handle_reply;
 static reply_handler dhcpv6_handle_advert;
@@ -69,19 +77,19 @@ static int dhcpv6_commit_advert(void);
 // RFC 3315 - 5.5 Timeout and Delay values
 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
 	[DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
- 			dhcpv6_handle_reconfigure, NULL},
-	[DHCPV6_MSG_SOLICIT] = {true, 1, 3600, 0, "SOLICIT",
- 			dhcpv6_handle_advert, dhcpv6_commit_advert},
-	[DHCPV6_MSG_REQUEST] = {true, 1, 30, 10, "REQUEST",
- 			dhcpv6_handle_reply, NULL},
-	[DHCPV6_MSG_RENEW] = {false, 10, 600, 0, "RENEW",
- 			dhcpv6_handle_reply, NULL},
-	[DHCPV6_MSG_REBIND] = {false, 10, 600, 0, "REBIND",
- 			dhcpv6_handle_rebind_reply, NULL},
+			dhcpv6_handle_reconfigure, NULL},
+	[DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
+			dhcpv6_handle_advert, dhcpv6_commit_advert},
+	[DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
+			dhcpv6_handle_reply, NULL},
+	[DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
+			dhcpv6_handle_reply, NULL},
+	[DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
+			dhcpv6_handle_rebind_reply, NULL},
 	[DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
 	[DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
-	[DHCPV6_MSG_INFO_REQ] = {true, 1, 120, 0, "INFOREQ",
- 			dhcpv6_handle_reply, NULL},
+	[DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
+			dhcpv6_handle_reply, NULL},
 };
 
 
@@ -98,19 +106,31 @@ static bool accept_reconfig = false;
 // Reconfigure key
 static uint8_t reconf_key[16];
 
+// client options
+static unsigned int client_options = 0;
 
 
-int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
+static uint32_t ntohl_unaligned(const uint8_t *data)
 {
-	request_prefix = request_pd;
+	uint32_t buf;
+
+	memcpy(&buf, data, sizeof(buf));
+	return ntohl(buf);
+}
+
+int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
+{
+	client_options = options;
 	dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 
 	sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
+	if (sock < 0)
+		return -1;
 
 	// Detect interface
 	struct ifreq ifr;
 	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
-	if (ioctl(sock, SIOCGIFINDEX, &ifr))
+	if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 		return -1;
 	ifindex = ifr.ifr_ifindex;
 
@@ -118,10 +138,11 @@ int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
 	size_t client_id_len;
 	odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 	if (client_id_len == 0) {
-		ioctl(sock, SIOCGIFHWADDR, &ifr);
 		uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 				DHCPV6_DUID_LLADDR, 0, 1};
-		memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
+
+		if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
+			memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 
 		uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 		struct ifreq ifs[100], *ifp, *ifend;
@@ -134,10 +155,12 @@ int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
 			// If our interface doesn't have an address...
 			ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 			for (ifp = ifc.ifc_req; ifp < ifend &&
-					!memcmp(&duid[8], zero, 6); ifp++) {
+					!memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 				memcpy(ifr.ifr_name, ifp->ifr_name,
 						sizeof(ifr.ifr_name));
-				ioctl(sock, SIOCGIFHWADDR, &ifr);
+				if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
+					continue;
+
 				memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 						ETHER_ADDR_LEN);
 			}
@@ -147,45 +170,75 @@ int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
 	}
 
 	// Create ORO
-	uint16_t oro[] = {
+	if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
+		uint16_t oro[] = {
 			htons(DHCPV6_OPT_SIP_SERVER_D),
 			htons(DHCPV6_OPT_SIP_SERVER_A),
 			htons(DHCPV6_OPT_DNS_SERVERS),
 			htons(DHCPV6_OPT_DNS_DOMAIN),
+			htons(DHCPV6_OPT_SNTP_SERVERS),
 			htons(DHCPV6_OPT_NTP_SERVER),
-			htons(DHCPV6_OPT_SIP_SERVER_A),
 			htons(DHCPV6_OPT_AFTR_NAME),
 			htons(DHCPV6_OPT_PD_EXCLUDE),
-#ifdef EXT_PREFIX_CLASS
-			htons(DHCPV6_OPT_PREFIX_CLASS),
+			htons(DHCPV6_OPT_SOL_MAX_RT),
+			htons(DHCPV6_OPT_INF_MAX_RT),
+#ifdef EXT_CER_ID
+			htons(DHCPV6_OPT_CER_ID),
 #endif
-	};
-	odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
-
+			htons(DHCPV6_OPT_S46_CONT_MAPE),
+			htons(DHCPV6_OPT_S46_CONT_MAPT),
+			htons(DHCPV6_OPT_S46_CONT_LW),
+		};
+		odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
+	}
 
 	// Configure IPv6-options
 	int val = 1;
 	setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
-	val = 0;
-	setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
+	setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 	setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 
 	struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 		.sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
-	if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
+	if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 		return -1;
 
 	return 0;
 }
 
+enum {
+	IOV_HDR=0,
+	IOV_ORO,
+	IOV_ORO_REFRESH,
+	IOV_CL_ID,
+	IOV_SRV_ID,
+	IOV_VENDOR_CLASS_HDR,
+	IOV_VENDOR_CLASS,
+	IOV_USER_CLASS_HDR,
+	IOV_USER_CLASS,
+	IOV_RECONF_ACCEPT,
+	IOV_FQDN,
+	IOV_HDR_IA_NA,
+	IOV_IA_NA,
+	IOV_IA_PD,
+	IOV_TOTAL
+};
 
-void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
+int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 {
+	int mode = DHCPV6_UNKNOWN;
+
 	na_mode = na;
 	pd_mode = pd;
-}
 
+	if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
+		mode = DHCPV6_STATELESS;
+	else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
+		mode = DHCPV6_STATEFUL;
+
+	return mode;
+}
 
 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 {
@@ -214,69 +267,128 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 	void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 
 	// Build IA_PDs
-	size_t ia_pd_entries, ia_pd_len = 0;
-	struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
-	ia_pd_entries /= sizeof(*e);
-	struct dhcpv6_ia_hdr hdr_ia_pd = {
-		htons(DHCPV6_OPT_IA_PD),
-		htons(sizeof(hdr_ia_pd) - 4),
-		1, 0, 0
-	};
+	size_t ia_pd_entries = 0, ia_pd_len = 0;
+	uint8_t *ia_pd;
 
+	if (type == DHCPV6_MSG_SOLICIT) {
+		odhcp6c_clear_state(STATE_IA_PD);
+		size_t n_prefixes;
+		struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
+		n_prefixes /= sizeof(struct odhcp6c_request_prefix);
+
+		ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
+
+		for (size_t i = 0; i < n_prefixes; i++) {
+			struct dhcpv6_ia_hdr hdr_ia_pd = {
+				htons(DHCPV6_OPT_IA_PD),
+				htons(sizeof(hdr_ia_pd) - 4 +
+				      sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
+				request_prefixes[i].iaid, 0, 0
+			};
+			struct dhcpv6_ia_prefix pref = {
+				.type = htons(DHCPV6_OPT_IA_PREFIX),
+				.len = htons(sizeof(pref) - 4),
+				.prefix = request_prefixes[i].length
+			};
+			memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
+			ia_pd_len += sizeof(hdr_ia_pd);
+			if (request_prefixes[i].length) {
+				memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
+				ia_pd_len += sizeof(pref);
+			}
+		}
+	} else {
+		struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
+		ia_pd_entries /= sizeof(*e);
+
+		// we're too lazy to count our distinct IAIDs,
+		// so just allocate maximally needed space
+		ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
+					sizeof(struct dhcpv6_ia_hdr)));
+
+		for (size_t i = 0; i < ia_pd_entries; ++i) {
+			uint32_t iaid = e[i].iaid;
+
+			// check if this is an unprocessed IAID and skip if not.
+			int new_iaid = 1;
+			for (int j = i-1; j >= 0; j--) {
+				if (e[j].iaid == iaid) {
+					new_iaid = 0;
+					break;
+				}
+			}
+
+			if (!new_iaid)
+				continue;
 
-	uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
-	for (size_t i = 0; i < ia_pd_entries; ++i) {
-		uint8_t ex_len = 0;
-		if (e[i].priority > 0)
-			ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
+			// construct header
+			struct dhcpv6_ia_hdr hdr_ia_pd = {
+				htons(DHCPV6_OPT_IA_PD),
+				htons(sizeof(hdr_ia_pd) - 4),
+				iaid, 0, 0
+			};
 
-		struct dhcpv6_ia_prefix p = {
-			.type = htons(DHCPV6_OPT_IA_PREFIX),
-			.len = htons(sizeof(p) - 4U + ex_len),
-			.prefix = e[i].length,
-			.addr = e[i].target
-		};
+			memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
+			struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
+			ia_pd_len += sizeof(hdr_ia_pd);
+
+			for (size_t j = i; j < ia_pd_entries; j++) {
+				if (e[j].iaid != iaid)
+					continue;
+
+				uint8_t ex_len = 0;
+				if (e[j].priority > 0)
+					ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
+
+				struct dhcpv6_ia_prefix p = {
+					.type = htons(DHCPV6_OPT_IA_PREFIX),
+					.len = htons(sizeof(p) - 4U + ex_len),
+					.prefix = e[j].length,
+					.addr = e[j].target
+				};
+
+				if (type == DHCPV6_MSG_REQUEST) {
+					p.preferred = htonl(e[j].preferred);
+					p.valid = htonl(e[j].valid);
+				}
+
+				memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
+				ia_pd_len += sizeof(p);
 
-		memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
-		ia_pd_len += sizeof(p);
+				if (ex_len) {
+					ia_pd[ia_pd_len++] = 0;
+					ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
+					ia_pd[ia_pd_len++] = 0;
+					ia_pd[ia_pd_len++] = ex_len - 4;
+					ia_pd[ia_pd_len++] = e[j].priority;
 
-		if (ex_len) {
-			ia_pd[ia_pd_len++] = 0;
-			ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
-			ia_pd[ia_pd_len++] = 0;
-			ia_pd[ia_pd_len++] = ex_len - 4;
-			ia_pd[ia_pd_len++] = e[i].priority;
+					uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
+					excl >>= (64 - e[j].priority);
+					excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 
-			uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
-			excl >>= (64 - e[i].priority);
-			excl <<= 8 - ((e[i].priority - e[i].length) % 8);
+					for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
+						ia_pd[ia_pd_len + i] = excl & 0xff;
+					ia_pd_len += ex_len - 5;
+				}
 
-			for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
-				ia_pd[ia_pd_len + i] = excl & 0xff;
-			ia_pd_len += ex_len - 5;
+				hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
+			}
 		}
 	}
 
-	struct dhcpv6_ia_prefix pref = {
-		.type = htons(DHCPV6_OPT_IA_PREFIX),
-		.len = htons(25), .prefix = request_prefix
-	};
-	if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
-		ia_pd = (uint8_t*)&pref;
-		ia_pd_len = sizeof(pref);
-	}
-	hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
+	if (ia_pd_entries > 0)
+		request_prefix = 1;
 
 	// Build IA_NAs
 	size_t ia_na_entries, ia_na_len = 0;
 	void *ia_na = NULL;
-	e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
+	struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 	ia_na_entries /= sizeof(*e);
 
 	struct dhcpv6_ia_hdr hdr_ia_na = {
 		htons(DHCPV6_OPT_IA_NA),
 		htons(sizeof(hdr_ia_na) - 4),
-		1, 0, 0
+		htonl(1), 0, 0
 	};
 
 	struct dhcpv6_ia_addr pa[ia_na_entries];
@@ -284,8 +396,14 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 		pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 		pa[i].len = htons(sizeof(pa[i]) - 4U);
 		pa[i].addr = e[i].target;
-		pa[i].preferred = 0;
-		pa[i].valid = 0;
+
+		if (type == DHCPV6_MSG_REQUEST) {
+			pa[i].preferred = htonl(e[i].preferred);
+			pa[i].valid = htonl(e[i].valid);
+		} else {
+			pa[i].preferred = 0;
+			pa[i].valid = 0;
+		}
 	}
 
 	ia_na = pa;
@@ -301,6 +419,21 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 	// Request Information Refresh
 	uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 
+	// Build vendor-class option
+	size_t vendor_class_len, user_class_len;
+	struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
+	void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
+
+	struct {
+		uint16_t type;
+		uint16_t length;
+	} vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
+
+	struct {
+		uint16_t type;
+		uint16_t length;
+	} user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
+
 	// Prepare Header
 	size_t oro_len;
 	void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
@@ -319,44 +452,50 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 		htons(DHCPV6_OPT_ORO), htons(oro_len),
 	};
 
-	struct iovec iov[] = {
-		{&hdr, sizeof(hdr)},
-		{oro, oro_len},
-		{&oro_refresh, 0},
-		{cl_id, cl_id_len},
-		{srv_id, srv_id_len},
-		{&reconf_accept, sizeof(reconf_accept)},
-		{&fqdn, fqdn_len},
-		{&hdr_ia_na, sizeof(hdr_ia_na)},
-		{ia_na, ia_na_len},
-		{&hdr_ia_pd, sizeof(hdr_ia_pd)},
-		{ia_pd, ia_pd_len},
+	struct iovec iov[IOV_TOTAL] = {
+		[IOV_HDR] = {&hdr, sizeof(hdr)},
+		[IOV_ORO] = {oro, oro_len},
+		[IOV_ORO_REFRESH] = {&oro_refresh, 0},
+		[IOV_CL_ID] = {cl_id, cl_id_len},
+		[IOV_SRV_ID] = {srv_id, srv_id_len},
+		[IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
+		[IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
+		[IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
+		[IOV_USER_CLASS] = {user_class, user_class_len},
+		[IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
+		[IOV_FQDN] = {&fqdn, fqdn_len},
+		[IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
+		[IOV_IA_NA] = {ia_na, ia_na_len},
+		[IOV_IA_PD] = {ia_pd, ia_pd_len},
 	};
 
-	size_t cnt = ARRAY_SIZE(iov);
+	size_t cnt = IOV_TOTAL;
 	if (type == DHCPV6_MSG_INFO_REQ) {
-		cnt = 5;
-		iov[2].iov_len = sizeof(oro_refresh);
+		cnt = 9;
+		iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 		hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 	} else if (!request_prefix) {
-		cnt = 9;
+		cnt = 13;
 	}
 
 	// Disable IAs if not used
-	if (type != DHCPV6_MSG_SOLICIT) {
-		iov[5].iov_len = 0;
-		if (ia_na_len == 0)
-			iov[7].iov_len = 0;
-		if (ia_pd_len == 0)
-			iov[9].iov_len = 0;
-	}
+	if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
+		iov[IOV_HDR_IA_NA].iov_len = 0;
 
 	if (na_mode == IA_MODE_NONE)
-		iov[7].iov_len = 0;
+		iov[IOV_HDR_IA_NA].iov_len = 0;
+
+	if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
+			!(client_options & DHCPV6_ACCEPT_RECONFIGURE))
+		iov[IOV_RECONF_ACCEPT].iov_len = 0;
+
+	if (!(client_options & DHCPV6_CLIENT_FQDN))
+		iov[IOV_FQDN].iov_len = 0;
 
 	struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 		0, ALL_DHCPV6_RELAYS, ifindex};
-	struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
+	struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
+			.msg_iov = iov, .msg_iovlen = cnt};
 
 	sendmsg(sock, &msg, 0);
 }
@@ -372,22 +511,22 @@ static int64_t dhcpv6_rand_delay(int64_t time)
 
 int dhcpv6_request(enum dhcpv6_msg type)
 {
-	uint8_t buf[1536], rc = 0;
+	uint8_t rc = 0;
 	uint64_t timeout = UINT32_MAX;
 	struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 
 	if (retx->delay) {
 		struct timespec ts = {0, 0};
-		ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
-		nanosleep(&ts, NULL);
+		ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
+		while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 	}
 
 	if (type == DHCPV6_MSG_UNKNOWN)
 		timeout = t1;
 	else if (type == DHCPV6_MSG_RENEW)
-		timeout = (t2 > t1) ? t2 - t1 : 0;
+		timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 	else if (type == DHCPV6_MSG_REBIND)
-		timeout = (t3 > t2) ? t3 - t2 : 0;
+		timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 
 	if (timeout == 0)
 		return -1;
@@ -425,66 +564,100 @@ int dhcpv6_request(enum dhcpv6_msg type)
 		uint64_t round_end = round_start + rto;
 		elapsed = round_start - start;
 
-		// Don't wait too long
-		if (round_end - start > timeout * 1000)
+		// Don't wait too long if timeout differs from infinite
+		if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 			round_end = timeout * 1000 + start;
 
 		// Built and send package
-		if (type != DHCPV6_MSG_UNKNOWN) {
+		switch (type) {
+		case DHCPV6_MSG_UNKNOWN:
+			break;
+		default:
 			syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 					retx->name, (unsigned long long)elapsed, rc);
+			// Fall through
+		case DHCPV6_MSG_SOLICIT:
+		case DHCPV6_MSG_INFO_REQ:
 			dhcpv6_send(type, trid, elapsed / 10);
 			rc++;
 		}
 
 		// Receive rounds
-		for (; len < 0 && round_start < round_end;
+		for (; len < 0 && (round_start < round_end);
 				round_start = odhcp6c_get_milli_time()) {
+			uint8_t buf[1536];
+			uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]
+				__aligned(__alignof__(struct cmsghdr));
+			struct iovec iov = {buf, sizeof(buf)};
+			struct sockaddr_in6 addr;
+			struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
+					.msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
+					.msg_controllen = sizeof(cmsg_buf)};
+			struct in6_pktinfo *pktinfo = NULL;
+
+
 			// Check for pending signal
 			if (odhcp6c_signal_process())
 				return -1;
 
 			// Set timeout for receiving
 			uint64_t t = round_end - round_start;
-			struct timeval timeout = {t / 1000, (t % 1000) * 1000};
+			struct timeval tv = {t / 1000, (t % 1000) * 1000};
 			setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
-					&timeout, sizeof(timeout));
+					&tv, sizeof(tv));
 
 			// Receive cycle
-			len = recv(sock, buf, sizeof(buf), 0);
+			len = recvmsg(sock, &msg, 0);
+			if (len < 0)
+				continue;
+
+			for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
+				ch = CMSG_NXTHDR(&msg, ch)) {
+				if (ch->cmsg_level == SOL_IPV6 &&
+					ch->cmsg_type == IPV6_PKTINFO) {
+					pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
+					break;
+				}
+			}
+
+			if (pktinfo == NULL) {
+				len = -1;
+				continue;
+			}
 
-			if (!dhcpv6_response_is_valid(buf, len, trid, type))
+			if (!dhcpv6_response_is_valid(buf, len, trid,
+							type, &pktinfo->ipi6_addr)) {
 				len = -1;
+				continue;
+			}
 
-			if (len > 0) {
-				uint8_t *opt = &buf[4];
-				uint8_t *opt_end = opt + len - 4;
+			uint8_t *opt = &buf[4];
+			uint8_t *opt_end = opt + len - 4;
 
-				round_start = odhcp6c_get_milli_time();
-				elapsed = round_start - start;
-				syslog(LOG_NOTICE, "Got a valid reply after "
-						"%llums", (unsigned long long)elapsed);
+			round_start = odhcp6c_get_milli_time();
+			elapsed = round_start - start;
+			syslog(LOG_NOTICE, "Got a valid reply after "
+					"%llums", (unsigned long long)elapsed);
 
-				if (retx->handler_reply)
-					len = retx->handler_reply(
-							type, rc, opt, opt_end);
+			if (retx->handler_reply)
+				len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 
-				if (len > 0 && round_end - round_start > 1000)
-					round_end = 1000 + round_start;
-			}
+			if (len > 0 && round_end - round_start > 1000)
+				round_end = 1000 + round_start;
 		}
 
 		// Allow
 		if (retx->handler_finish)
 			len = retx->handler_finish();
-	} while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
-
+	} while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) && 
+			(!retx->max_rc || rc < retx->max_rc));
 	return len;
 }
 
-
+// Message validation checks according to RFC3315 chapter 15
 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
-		const uint8_t transaction[3], enum dhcpv6_msg type)
+		const uint8_t transaction[3], enum dhcpv6_msg type,
+		const struct in6_addr *daddr)
 {
 	const struct dhcpv6_header *rep = buf;
 	if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
@@ -502,9 +675,11 @@ static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 		return false;
 	}
 
-	uint8_t *end = ((uint8_t*)buf) + len, *odata;
-	uint16_t otype, olen;
-	bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
+	uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
+		rcmsg = DHCPV6_MSG_UNKNOWN;
+	uint16_t otype, olen = UINT16_MAX;
+	bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
+		ia_present = false, options_valid = true;
 
 	size_t client_id_len, server_id_len;
 	void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
@@ -515,46 +690,73 @@ static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 			clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 					&odata[-4], client_id, client_id_len);
 		} else if (otype == DHCPV6_OPT_SERVERID) {
-			serverid_ok = (olen + 4U == server_id_len) && !memcmp(
-					&odata[-4], server_id, server_id_len);
+			if (server_id_len)
+				serverid_ok = (olen + 4U == server_id_len) && !memcmp(
+						&odata[-4], server_id, server_id_len);
+			else
+				serverid_ok = true;
 		} else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 				sizeof(struct dhcpv6_auth_reconfigure)) {
 			struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 			if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 				continue;
 
-			md5_state_t md5;
-			uint8_t serverhash[16], secretbytes[16], hash[16];
+			md5_ctx_t md5;
+			uint8_t serverhash[16], secretbytes[64];
+			uint32_t hash[4];
 			memcpy(serverhash, r->key, sizeof(serverhash));
 			memset(r->key, 0, sizeof(r->key));
-			memcpy(secretbytes, reconf_key, sizeof(secretbytes));
+
+			memset(secretbytes, 0, sizeof(secretbytes));
+			memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 
 			for (size_t i = 0; i < sizeof(secretbytes); ++i)
 				secretbytes[i] ^= 0x36;
 
-			md5_init(&md5);
-			md5_append(&md5, secretbytes, sizeof(secretbytes));
-			md5_append(&md5, buf, len);
-			md5_finish(&md5, hash);
+			md5_begin(&md5);
+			md5_hash(secretbytes, sizeof(secretbytes), &md5);
+			md5_hash(buf, len, &md5);
+			md5_end(hash, &md5);
 
 			for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 				secretbytes[i] ^= 0x36;
 				secretbytes[i] ^= 0x5c;
 			}
 
-			md5_init(&md5);
-			md5_append(&md5, secretbytes, sizeof(secretbytes));
-			md5_append(&md5, hash, 16);
-			md5_finish(&md5, hash);
+			md5_begin(&md5);
+			md5_hash(secretbytes, sizeof(secretbytes), &md5);
+			md5_hash(hash, 16, &md5);
+			md5_end(hash, &md5);
 
 			rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
+		} else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
+			rcmsg = odata[0];
+		} else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
+			ia_present = true;
+			if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
+				options_valid = false;
+		}
+		else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
+				(otype == DHCPV6_OPT_PD_EXCLUDE)) {
+			// Options are not allowed on global level
+			options_valid = false;
 		}
 	}
 
-	if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
+	if (!options_valid || ((odata + olen) > end))
+		return false;
+
+	if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 		return false;
 
-	return clientid_ok && (serverid_ok || server_id_len == 0);
+	if (rep->msg_type == DHCPV6_MSG_RECONF) {
+		if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
+			(rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
+			!rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
+			return false;
+	}
+
+	return clientid_ok && serverid_ok;
 }
 
 
@@ -569,9 +771,8 @@ int dhcpv6_poll_reconfigure(void)
 
 
 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
-		const void *opt, const void *end)
+		const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 {
-	// TODO: should verify the reconfigure message
 	uint16_t otype, olen;
 	uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 	dhcpv6_for_each_option(opt, end, otype, olen, odata)
@@ -580,25 +781,27 @@ static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 				odata[0] == DHCPV6_MSG_INFO_REQ))
 			msg = odata[0];
 
-	dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
+	dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 	return msg;
 }
 
 
 // Collect all advertised servers
 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
-		const void *opt, const void *end)
+		const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 {
 	uint16_t olen, otype;
 	uint8_t *odata, pref = 0;
-	struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
+	struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
+					DHCPV6_SOL_MAX_RT,
+					DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 	bool have_na = false;
 	int have_pd = 0;
 
 	dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 		if (orig == DHCPV6_MSG_SOLICIT &&
 				(otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
-				olen > sizeof(struct dhcpv6_ia_hdr)) {
+				olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 			struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 			dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 		}
@@ -606,53 +809,54 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 		if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 			memcpy(cand.duid, odata, olen);
 			cand.duid_len = olen;
-		} else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
-			int error = ((int)odata[0] << 8 | (int)odata[1]);
-
-			switch (error) {
-			case DHCPV6_NoPrefixAvail:
-				// Status code on global level
-				if (pd_mode == IA_MODE_FORCE)
-					return -1;
-				cand.preference -= 2000;
-				break;
-
-			case DHCPV6_NoAddrsAvail:
-				// Status code on global level
-				if (na_mode == IA_MODE_FORCE)
-					return -1;
-				break;
-
-			default :
-				break;
-			}
 		} else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 				cand.preference >= 0) {
 			cand.preference = pref = odata[0];
 		} else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 			cand.wants_reconfigure = true;
-		} else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
+		} else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
+			uint32_t sol_max_rt = ntohl_unaligned(odata);
+			if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
+					sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
+				cand.sol_max_rt = sol_max_rt;
+		} else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
+			uint32_t inf_max_rt = ntohl_unaligned(odata);
+			if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
+					inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
+				cand.inf_max_rt = inf_max_rt;
+		} else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
+					olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 			struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 			uint8_t *oend = odata + olen, *d;
 			dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
-				if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
-						(uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
+				if (otype == DHCPV6_OPT_IA_PREFIX &&
+						olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 					struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 					have_pd = p->prefix;
 				}
 			}
-		} else if (otype == DHCPV6_OPT_IA_NA) {
+		} else if (otype == DHCPV6_OPT_IA_NA &&
+					olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 			struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 			uint8_t *oend = odata + olen, *d;
 			dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
-				if (otype == DHCPV6_OPT_IA_ADDR)
+				if (otype == DHCPV6_OPT_IA_ADDR &&
+						olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 					have_na = true;
 		}
 	}
 
 	if ((!have_na && na_mode == IA_MODE_FORCE) ||
-			(!have_pd && pd_mode == IA_MODE_FORCE))
+			(!have_pd && pd_mode == IA_MODE_FORCE)) {
+		/*
+		 * RFC7083 states to process the SOL_MAX_RT and
+		 * INF_MAX_RT options even if the DHCPv6 server
+		 * did not propose any IA_NA and/or IA_PD
+		 */
+		dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
+		dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 		return -1;
+	}
 
 	if (na_mode != IA_MODE_NONE && !have_na) {
 		cand.has_noaddravail = true;
@@ -669,12 +873,7 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 	if (cand.duid_len > 0) {
 		cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 		cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
-		odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
-	}
-
-	if (orig == DHCPV6_MSG_SOLICIT) {
-		odhcp6c_clear_state(STATE_IA_NA);
-		odhcp6c_clear_state(STATE_IA_PD);
+		dhcpv6_add_server_cand(&cand);
 	}
 
 	return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
@@ -683,71 +882,27 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 
 static int dhcpv6_commit_advert(void)
 {
-	size_t cand_len;
-	struct dhcpv6_server_cand *c = NULL, *cand =
-			odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
-
-	bool retry = false;
-	for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
-		if (cand[i].has_noaddravail)
-			retry = true; // We want to try again
-
-		if (!c || c->preference < cand[i].preference)
-			c = &cand[i];
-	}
-
-	if (retry && na_mode == IA_MODE_TRY) {
-		// We give it a second try without the IA_NA
-		na_mode = IA_MODE_NONE;
-		return dhcpv6_request(DHCPV6_MSG_SOLICIT);
-	}
-
-	if (c) {
-		uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
-				htons(c->duid_len)};
-		odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
-		odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
-		accept_reconfig = c->wants_reconfigure;
-		if (c->ia_na_len)
-			odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
-		if (c->ia_pd_len)
-			odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
-	}
-
-	for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
-		free(cand[i].ia_na);
-		free(cand[i].ia_pd);
-	}
-	odhcp6c_clear_state(STATE_SERVER_CAND);
-
-	if (!c)
-		return -1;
-	else if ((request_prefix && c->ia_pd_len) || (na_mode != IA_MODE_NONE && c->ia_na_len))
-		return DHCPV6_STATEFUL;
-	else
-		return DHCPV6_STATELESS;
+	return dhcpv6_promote_server_cand();
 }
 
 
 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
-		const void *opt, const void *end)
+		const void *opt, const void *end, const struct sockaddr_in6 *from)
 {
-	dhcpv6_handle_advert(orig, rc, opt, end);
-	if (dhcpv6_commit_advert() < 0) {
-		dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
+	dhcpv6_handle_advert(orig, rc, opt, end, from);
+	if (dhcpv6_commit_advert() < 0)
 		return -1;
-	}
 
-	return dhcpv6_handle_reply(orig, rc, opt, end);
+	return dhcpv6_handle_reply(orig, rc, opt, end, from);
 }
 
 
 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
-		const void *opt, const void *end)
+		const void *opt, const void *end, const struct sockaddr_in6 *from)
 {
 	uint8_t *odata;
 	uint16_t otype, olen;
-	uint32_t refresh = UINT32_MAX;
+	uint32_t refresh = 86400;
 	int ret = 1;
 	bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 
@@ -760,9 +915,14 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 		uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 		last_update = now;
 
-		t1 -= elapsed;
-		t2 -= elapsed;
-		t3 -= elapsed;
+		if (t1 != UINT32_MAX)
+			t1 -= elapsed;
+
+		if (t2 != UINT32_MAX)
+			t2 -= elapsed;
+
+		if (t3 != UINT32_MAX)
+			t3 -= elapsed;
 
 		if (t1 < 0)
 			t1 = 0;
@@ -784,99 +944,163 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 		odhcp6c_clear_state(STATE_DNS);
 		odhcp6c_clear_state(STATE_SEARCH);
 		odhcp6c_clear_state(STATE_SNTP_IP);
-		odhcp6c_clear_state(STATE_SNTP_FQDN);
+		odhcp6c_clear_state(STATE_NTP_IP);
+		odhcp6c_clear_state(STATE_NTP_FQDN);
 		odhcp6c_clear_state(STATE_SIP_IP);
 		odhcp6c_clear_state(STATE_SIP_FQDN);
 		odhcp6c_clear_state(STATE_AFTR_NAME);
-	}
-
-	// Parse and find all matching IAs
-	dhcpv6_for_each_option(opt, end, otype, olen, odata) {
-		if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
-				&& olen > sizeof(struct dhcpv6_ia_hdr)) {
-			struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
+		odhcp6c_clear_state(STATE_CER);
+		odhcp6c_clear_state(STATE_S46_MAPT);
+		odhcp6c_clear_state(STATE_S46_MAPE);
+		odhcp6c_clear_state(STATE_S46_LW);
+		odhcp6c_clear_state(STATE_PASSTHRU);
+		odhcp6c_clear_state(STATE_CUSTOM_OPTS);
+
+		// Parse and find all matching IAs
+		dhcpv6_for_each_option(opt, end, otype, olen, odata) {
+			bool passthru = true;
+
+			if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
+					&& olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
+				struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
+
+				if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
+					(pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
+					continue;
 
-			// Test ID
-			if (ia_hdr->iaid != 1)
-				continue;
+				// Test ID
+				if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
+					continue;
 
-			uint16_t code = DHCPV6_Success;
-			uint16_t stype, slen;
-			uint8_t *sdata;
-			// Get and handle status code
-			dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
-					stype, slen, sdata) {
-				if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
-					uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
-					uint16_t mlen = (slen > 2) ? slen - 2 : 0;
+				uint16_t code = DHCPV6_Success;
+				uint16_t stype, slen;
+				uint8_t *sdata;
+				// Get and handle status code
+				dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
+						stype, slen, sdata) {
+					if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
+						uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
+						uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 
-					code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
+						code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 
-					if (code == DHCPV6_Success)
-						continue;
+						if (code == DHCPV6_Success)
+							continue;
 
-					dhcpv6_handle_ia_status_code(orig, ia_hdr,
-						code, mdata, mlen, handled_status_codes, &ret);
+						dhcpv6_handle_ia_status_code(orig, ia_hdr,
+							code, mdata, mlen, handled_status_codes, &ret);
 
 
-					if (ret > 0)
-						return ret;
-					break;
+						if (ret > 0)
+							return ret;
+						break;
+					}
 				}
-			}
 
-			if (code != DHCPV6_Success)
-				continue;
+				if (code != DHCPV6_Success)
+					continue;
 
-			dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
-		} else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
-			uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
-			uint16_t mlen = (olen > 2) ? olen - 2 : 0;
-			uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
+				dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
+				uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
+				uint16_t mlen = (olen > 2) ? olen - 2 : 0;
+				uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 
-			dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
-		}
-		else if (otype == DHCPV6_OPT_DNS_SERVERS) {
-			if (olen % 16 == 0)
-				odhcp6c_add_state(STATE_DNS, odata, olen);
-		} else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
-			odhcp6c_add_state(STATE_SEARCH, odata, olen);
-		} else if (otype == DHCPV6_OPT_NTP_SERVER) {
-			uint16_t stype, slen;
-			uint8_t *sdata;
-			// Test status and bail if error
-			dhcpv6_for_each_option(odata, odata + olen,
-					stype, slen, sdata) {
-				if (slen == 16 && (stype == NTP_MC_ADDR ||
-						stype == NTP_SRV_ADDR))
-					odhcp6c_add_state(STATE_SNTP_IP,
-							sdata, slen);
-				else if (slen > 0 && stype == NTP_SRV_FQDN)
-					odhcp6c_add_state(STATE_SNTP_FQDN,
-							sdata, slen);
+				dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
+				passthru = false;
 			}
-		} else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
-			if (olen == 16)
-				odhcp6c_add_state(STATE_SIP_IP, odata, olen);
-		} else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
-			odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
-		} else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
-			refresh = ntohl(*((uint32_t*)odata));
-		} else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
-				sizeof(struct dhcpv6_auth_reconfigure)) {
-			struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
-			if (r->protocol == 3 && r->algorithm == 1 &&
-					r->reconf_type == 1)
-				memcpy(reconf_key, r->key, sizeof(r->key));
-		} else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
-			size_t cur_len;
-			odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
-			if (cur_len == 0)
-				odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
-		} else if (otype != DHCPV6_OPT_CLIENTID &&
-				otype != DHCPV6_OPT_SERVERID) {
-			odhcp6c_add_state(STATE_CUSTOM_OPTS,
-					&odata[-4], olen + 4);
+			else if (otype == DHCPV6_OPT_DNS_SERVERS) {
+				if (olen % 16 == 0)
+					odhcp6c_add_state(STATE_DNS, odata, olen);
+			} else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
+				odhcp6c_add_state(STATE_SEARCH, odata, olen);
+			} else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
+				if (olen % 16 == 0)
+					odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
+			} else if (otype == DHCPV6_OPT_NTP_SERVER) {
+				uint16_t stype, slen;
+				uint8_t *sdata;
+				// Test status and bail if error
+				dhcpv6_for_each_option(odata, odata + olen,
+						stype, slen, sdata) {
+					if (slen == 16 && (stype == NTP_MC_ADDR ||
+							stype == NTP_SRV_ADDR))
+						odhcp6c_add_state(STATE_NTP_IP,
+								sdata, slen);
+					else if (slen > 0 && stype == NTP_SRV_FQDN)
+						odhcp6c_add_state(STATE_NTP_FQDN,
+								sdata, slen);
+				}
+			} else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
+				if (olen == 16)
+					odhcp6c_add_state(STATE_SIP_IP, odata, olen);
+			} else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
+				odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
+			} else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
+				refresh = ntohl_unaligned(odata);
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_AUTH) {
+				if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
+					struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
+					if (r->protocol == 3 && r->algorithm == 1 &&
+							r->reconf_type == 1)
+						memcpy(reconf_key, r->key, sizeof(r->key));
+				}
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
+				size_t cur_len;
+				odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
+				if (cur_len == 0)
+					odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
+				uint32_t sol_max_rt = ntohl_unaligned(odata);
+				if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
+						sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
+					dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
+				uint32_t inf_max_rt = ntohl_unaligned(odata);
+				if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
+						inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
+					dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
+				passthru = false;
+	#ifdef EXT_CER_ID
+			} else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
+					sizeof(struct dhcpv6_cer_id)) {
+				struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
+				struct in6_addr any = IN6ADDR_ANY_INIT;
+				if (memcmp(&cer_id->addr, &any, sizeof(any)))
+					odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
+				passthru = false;
+	#endif
+			} else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
+				odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
+				size_t mape_len;
+				odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
+				if (mape_len == 0)
+					odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_S46_CONT_LW) {
+				odhcp6c_add_state(STATE_S46_LW, odata, olen);
+				passthru = false;
+			} else if (otype == DHCPV6_OPT_CLIENTID ||
+					otype == DHCPV6_OPT_SERVERID ||
+					otype == DHCPV6_OPT_IA_TA ||
+					otype == DHCPV6_OPT_PREF ||
+					otype == DHCPV6_OPT_UNICAST ||
+					otype == DHCPV6_OPT_FQDN ||
+					otype == DHCPV6_OPT_RECONF_ACCEPT) {
+				passthru = false;
+			} else {
+				odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
+			}
+
+			if (passthru)
+				odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
 		}
 	}
 
@@ -895,13 +1119,28 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 					ret = -1;
 				break;
 
+			case DHCPV6_MSG_REQUEST:
+				// All server candidates can be cleared if not yet bound
+				if (!odhcp6c_is_bound())
+					dhcpv6_clear_all_server_cand();
+
 			default :
 				break;
 			}
+
+			if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
+				odhcp6c_clear_state(STATE_SERVER_ADDR);
+				odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
+			}
 		}
 	}
-	else if (ret > 0)
+	else if (ret > 0) {
+		// All server candidates can be cleared if not yet bound
+		if (!odhcp6c_is_bound())
+			dhcpv6_clear_all_server_cand();
+
 		t1 = refresh;
+	}
 
 	return ret;
 }
@@ -923,9 +1162,11 @@ static int dhcpv6_parse_ia(void *opt, void *end)
 
 	// Update address IA
 	dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
-		struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
+		struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
 				IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
 
+		entry.iaid = ia_hdr->iaid;
+
 		if (otype == DHCPV6_OPT_IA_PREFIX) {
 			struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
 			if (olen + 4U < sizeof(*prefix))
@@ -947,14 +1188,6 @@ static int dhcpv6_parse_ia(void *opt, void *end)
 			uint16_t stype, slen;
 			uint8_t *sdata;
 
-#ifdef EXT_PREFIX_CLASS
-                        // Find prefix class, if any
-			dhcpv6_for_each_option(&prefix[1], odata + olen,
-					stype, slen, sdata)
-				if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
-					entry.class = sdata[0] << 8 | sdata[1];
-#endif
-
 			// Parse PD-exclude
 			bool ok = true;
 			dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
@@ -966,7 +1199,7 @@ static int dhcpv6_parse_ia(void *opt, void *end)
 				if (elen > 64)
 					elen = 64;
 
-				if (elen <= 32 || elen <= entry.length) {
+				if (entry.length < 32 || elen <= entry.length) {
 					ok = false;
 					continue;
 				}
@@ -993,7 +1226,7 @@ static int dhcpv6_parse_ia(void *opt, void *end)
 			}
 
 			if (ok) {
-				odhcp6c_update_entry(STATE_IA_PD, &entry);
+				odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
 				parsed_ia++;
 			}
 
@@ -1018,17 +1251,7 @@ static int dhcpv6_parse_ia(void *opt, void *end)
 			entry.length = 128;
 			entry.target = addr->addr;
 
-#ifdef EXT_PREFIX_CLASS
-			uint16_t stype, slen;
-			uint8_t *sdata;
-			// Find prefix class, if any
-			dhcpv6_for_each_option(&addr[1], odata + olen,
-					stype, slen, sdata)
-				if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
-					entry.class = sdata[0] << 8 | sdata[1];
-#endif
-
-			odhcp6c_update_entry(STATE_IA_NA, &entry);
+			odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
 			parsed_ia++;
 		}
 	}
@@ -1072,6 +1295,8 @@ static int dhcpv6_calc_refresh_timers(void)
 		t1 = l_t1;
 		t2 = l_t2;
 		t3 = l_t3;
+	} else {
+		t1 = 600;
 	}
 
 	return (int)(ia_pd_entries + ia_na_entries);
@@ -1079,16 +1304,22 @@ static int dhcpv6_calc_refresh_timers(void)
 
 
 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
-		const void *status_msg, const int len)
+		const void *status_msg, int len)
 {
-	uint8_t buf[len + 3];
+	const char *src = status_msg;
+	char buf[len + 3];
+	char *dst = buf;
 
-	memset(buf, 0, sizeof(buf));
 	if (len) {
-		buf[0] = '(';
-		memcpy(&buf[1], status_msg, len);
-		buf[len + 1] = ')';
+		*dst++ = '(';
+		while (len--) {
+			*dst = isprint((unsigned char)*src) ? *src : '?';
+			src++;
+			dst++;
+		}
+		*dst++ = ')';
 	}
+	*dst = 0;
 
 	syslog(LOG_WARNING, "Server returned %s status %i %s",
 		scope, code, buf);
@@ -1145,23 +1376,100 @@ static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
 		}
 		break;
 
-	case DHCPV6_NoAddrsAvail:
-	case DHCPV6_NoPrefixAvail:
-		switch (orig) {
-		case DHCPV6_MSG_REQUEST:
-			if (*ret != 0)
-				*ret = 0;
-			break;
-		default:
+	default:
+		*ret = 0;
+		break;
+	}
+}
+
+// Note this always takes ownership of cand->ia_na and cand->ia_pd
+static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
+{
+	size_t cand_len, i;
+	struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
+
+	// Remove identical duid server candidate
+	for (i = 0; i < cand_len / sizeof(*c); ++i) {
+		if (cand->duid_len == c[i].duid_len &&
+				!memcmp(cand->duid, c[i].duid, cand->duid_len)) {
+			free(c[i].ia_na);
+			free(c[i].ia_pd);
+			odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
 			break;
 		}
-		break;
+	}
 
-	case DHCPV6_NotOnLink:
-		// TODO handle not onlink in case of confirm
-		break;
+	for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
+		i < cand_len / sizeof(*c); ++i) {
+		if (c[i].preference < cand->preference)
+			break;
+	}
 
-	default:
-		break;
+	if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
+		free(cand->ia_na);
+		free(cand->ia_pd);
 	}
 }
+
+static void dhcpv6_clear_all_server_cand(void)
+{
+	size_t cand_len, i;
+	struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
+
+	// Server candidates need deep delete for IA_NA/IA_PD
+	for (i = 0; i < cand_len / sizeof(*c); ++i) {
+		free(c[i].ia_na);
+		free(c[i].ia_pd);
+	}
+	odhcp6c_clear_state(STATE_SERVER_CAND);
+}
+
+int dhcpv6_promote_server_cand(void)
+{
+	size_t cand_len;
+	struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
+	uint16_t hdr[2];
+	int ret = DHCPV6_STATELESS;
+
+	// Clear lingering candidate state info
+	odhcp6c_clear_state(STATE_SERVER_ID);
+	odhcp6c_clear_state(STATE_IA_NA);
+	odhcp6c_clear_state(STATE_IA_PD);
+
+	if (!cand_len)
+		return -1;
+
+	if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
+		na_mode = IA_MODE_NONE;
+
+		dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
+		dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
+
+		return dhcpv6_request(DHCPV6_MSG_SOLICIT);
+	}
+
+	hdr[0] = htons(DHCPV6_OPT_SERVERID);
+	hdr[1] = htons(cand->duid_len);
+	odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
+	odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
+	accept_reconfig = cand->wants_reconfigure;
+	if (cand->ia_na_len) {
+		odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
+		free(cand->ia_na);
+		if (na_mode != IA_MODE_NONE)
+			ret = DHCPV6_STATEFUL;
+	}
+	if (cand->ia_pd_len) {
+		odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
+		free(cand->ia_pd);
+		if (request_prefix)
+			ret = DHCPV6_STATEFUL;
+	}
+
+	dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
+	dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
+
+	odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
+
+	return ret;
+}