[RFC 01/12] ip: Introduce multi-address data structures for IPv4 and IPv6

[Jon Maloy <jmaloy@redhat.com>]

As preparation for supporting multiple addresses per interface, we
replace the single addr/prefix_len fields with arrays.

- We add an ip4_addr_entry and an ip6_addr_entry struct containing
  address and prefix length.

- We set the array sizes to IP4_MAX_ADDRS=8 and IP6_MAX_ADDRS=16,
  respectively.

The only functional change is that the IPv6 prefix length now is
properly stored instead of being hardcoded to 64 even when set
via the -a option.

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 arp.c    |  4 +--
 conf.c   | 97 +++++++++++++++++++++++++++++++++-----------------------
 dhcp.c   |  8 ++---
 dhcpv6.c |  6 ++--
 fwd.c    | 12 +++----
 ip.h     | 26 +++++++++++++++
 ndp.c    |  6 ++--
 passt.h  | 16 ++++++----
 pasta.c  | 12 ++++---
 tap.c    |  4 +--
 util.h   |  1 +
 11 files changed, 122 insertions(+), 70 deletions(-)

diff --git a/arp.c b/arp.c
index bb042e9..7eaf517 100644
--- a/arp.c
+++ b/arp.c
@@ -54,7 +54,7 @@ static bool ignore_arp(const struct ctx *c,
 		return true;
 
 	/* Don't resolve the guest's assigned address, either. */
-	if (!memcmp(am->tip, &c->ip4.addr, sizeof(am->tip)))
+	if (!memcmp(am->tip, &c->ip4.addrs[0].addr, sizeof(am->tip)))
 		return true;
 
 	return false;
@@ -145,7 +145,7 @@ void arp_send_init_req(const struct ctx *c)
 	memcpy(req.am.sha,	c->our_tap_mac,		sizeof(req.am.sha));
 	memcpy(req.am.sip,	&c->ip4.our_tap_addr,	sizeof(req.am.sip));
 	memcpy(req.am.tha,	MAC_BROADCAST,		sizeof(req.am.tha));
-	memcpy(req.am.tip,	&c->ip4.addr,		sizeof(req.am.tip));
+	memcpy(req.am.tip,	&c->ip4.addrs[0].addr,	sizeof(req.am.tip));
 
 	debug("Sending initial ARP request for guest MAC address");
 	tap_send_single(c, &req, sizeof(req));
diff --git a/conf.c b/conf.c
index fdc19e8..0e96f36 100644
--- a/conf.c
+++ b/conf.c
@@ -694,10 +694,12 @@ static int conf_ip4_prefix(const char *arg)
  * conf_ip4() - Verify or detect IPv4 support, get relevant addresses
  * @ifi:	Host interface to attempt (0 to determine one)
  * @ip4:	IPv4 context (will be written)
+ * @permanent:	Mark configured addresses as permanent
  *
  * Return: interface index for IPv4, or 0 on failure.
  */
-static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
+static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4,
+			     bool permanent)
 {
 	if (!ifi)
 		ifi = nl_get_ext_if(nl_sock, AF_INET);
@@ -717,33 +719,38 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
 		}
 	}
 
-	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr)) {
+	if (!ip4->addr_count) {
 		int rc = nl_addr_get(nl_sock, ifi, AF_INET,
-				     &ip4->addr, &ip4->prefix_len, NULL);
+				     &ip4->addrs[0].addr,
+				     &ip4->addrs[0].prefix_len, NULL);
 		if (rc < 0) {
 			debug("Couldn't discover IPv4 address: %s",
 			      strerror_(-rc));
 			return 0;
 		}
+		ip4->addrs[0].permanent = permanent;
+		ip4->addr_count = 1;
 	}
 
-	if (!ip4->prefix_len) {
-		in_addr_t addr = ntohl(ip4->addr.s_addr);
-		if (IN_CLASSA(addr))
-			ip4->prefix_len = (32 - IN_CLASSA_NSHIFT);
-		else if (IN_CLASSB(addr))
-			ip4->prefix_len = (32 - IN_CLASSB_NSHIFT);
-		else if (IN_CLASSC(addr))
-			ip4->prefix_len = (32 - IN_CLASSC_NSHIFT);
+	/* Apply default prefix_len to first address if not set */
+	if (!ip4->addrs[0].prefix_len) {
+		in_addr_t a = ntohl(ip4->addrs[0].addr.s_addr);
+
+		if (IN_CLASSA(a))
+			ip4->addrs[0].prefix_len = 8;
+		else if (IN_CLASSB(a))
+			ip4->addrs[0].prefix_len = 16;
+		else if (IN_CLASSC(a))
+			ip4->addrs[0].prefix_len = 24;
 		else
-			ip4->prefix_len = 32;
+			ip4->addrs[0].prefix_len = 32;
 	}
 
-	ip4->addr_seen = ip4->addr;
+	ip4->addr_seen = ip4->addrs[0].addr;
 
 	ip4->our_tap_addr = ip4->guest_gw;
 
-	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr))
+	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addrs[0].addr))
 		return 0;
 
 	return ifi;
@@ -755,9 +762,9 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
  */
 static void conf_ip4_local(struct ip4_ctx *ip4)
 {
-	ip4->addr_seen = ip4->addr = IP4_LL_GUEST_ADDR;
+	ip4->addr_seen = ip4->addrs[0].addr = IP4_LL_GUEST_ADDR;
 	ip4->our_tap_addr = ip4->guest_gw = IP4_LL_GUEST_GW;
-	ip4->prefix_len = IP4_LL_PREFIX_LEN;
+	ip4->addrs[0].prefix_len = IP4_LL_PREFIX_LEN;
 
 	ip4->no_copy_addrs = ip4->no_copy_routes = true;
 }
@@ -766,10 +773,12 @@ static void conf_ip4_local(struct ip4_ctx *ip4)
  * conf_ip6() - Verify or detect IPv6 support, get relevant addresses
  * @ifi:	Host interface to attempt (0 to determine one)
  * @ip6:	IPv6 context (will be written)
+ * @permanent:	Mark discovered addresses as permanent
  *
  * Return: interface index for IPv6, or 0 on failure.
  */
-static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
+static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6,
+			     bool permanent)
 {
 	int prefix_len = 0;
 	int rc;
@@ -792,19 +801,25 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
 	}
 
 	rc = nl_addr_get(nl_sock, ifi, AF_INET6,
-			 IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ? &ip6->addr : NULL,
+			 ip6->addr_count ? NULL : &ip6->addrs[0].addr,
 			 &prefix_len, &ip6->our_tap_ll);
 	if (rc < 0) {
 		debug("Couldn't discover IPv6 address: %s", strerror_(-rc));
 		return 0;
 	}
 
-	ip6->addr_seen = ip6->addr;
+	if (!ip6->addr_count) {
+		ip6->addrs[0].prefix_len = prefix_len ? prefix_len : 64;
+		ip6->addrs[0].permanent = permanent;
+		ip6->addr_count = 1;
+	}
+
+	ip6->addr_seen = ip6->addrs[0].addr;
 
 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->guest_gw))
 		ip6->our_tap_ll = ip6->guest_gw;
 
-	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ||
+	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->addrs[0].addr) ||
 	    IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll))
 		return 0;
 
@@ -1149,11 +1164,13 @@ static void conf_print(const struct ctx *c)
 		if (!c->no_dhcp) {
 			uint32_t mask;
 
-			mask = htonl(0xffffffff << (32 - c->ip4.prefix_len));
+			mask = htonl(0xffffffff <<
+				     (32 - c->ip4.addrs[0].prefix_len));
 
 			info("DHCP:");
 			info("    assign: %s",
-			     inet_ntop(AF_INET, &c->ip4.addr, buf4, sizeof(buf4)));
+			     inet_ntop(AF_INET, &c->ip4.addrs[0].addr,
+				       buf4, sizeof(buf4)));
 			info("    mask: %s",
 			     inet_ntop(AF_INET, &mask,        buf4, sizeof(buf4)));
 			info("    router: %s",
@@ -1191,7 +1208,8 @@ static void conf_print(const struct ctx *c)
 			goto dns6;
 
 		info("    assign: %s",
-		     inet_ntop(AF_INET6, &c->ip6.addr, buf6, sizeof(buf6)));
+		     inet_ntop(AF_INET6, &c->ip6.addrs[0].addr,
+			       buf6, sizeof(buf6)));
 		info("    router: %s",
 		     inet_ntop(AF_INET6, &c->ip6.guest_gw, buf6, sizeof(buf6)));
 		info("    our link-local: %s",
@@ -1812,22 +1830,23 @@ void conf(struct ctx *c, int argc, char **argv)
 			break;
 		}
 		case 'a':
-			if (inet_pton(AF_INET6, optarg, &c->ip6.addr)	&&
-			    !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)	&&
-			    !IN6_IS_ADDR_LOOPBACK(&c->ip6.addr)		&&
-			    !IN6_IS_ADDR_V4MAPPED(&c->ip6.addr)		&&
-			    !IN6_IS_ADDR_V4COMPAT(&c->ip6.addr)		&&
-			    !IN6_IS_ADDR_MULTICAST(&c->ip6.addr)) {
+			if (inet_pton(AF_INET6, optarg,
+				      &c->ip6.addrs[0].addr) &&
+			    !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addrs[0].addr) &&
+			    !IN6_IS_ADDR_LOOPBACK(&c->ip6.addrs[0].addr) &&
+			    !IN6_IS_ADDR_V4MAPPED(&c->ip6.addrs[0].addr) &&
+			    !IN6_IS_ADDR_V4COMPAT(&c->ip6.addrs[0].addr) &&
+			    !IN6_IS_ADDR_MULTICAST(&c->ip6.addrs[0].addr)) {
 				if (c->mode == MODE_PASTA)
 					c->ip6.no_copy_addrs = true;
 				break;
 			}
 
-			if (inet_pton(AF_INET, optarg, &c->ip4.addr)	&&
-			    !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addr)	&&
-			    !IN4_IS_ADDR_BROADCAST(&c->ip4.addr)	&&
-			    !IN4_IS_ADDR_LOOPBACK(&c->ip4.addr)		&&
-			    !IN4_IS_ADDR_MULTICAST(&c->ip4.addr)) {
+			if (inet_pton(AF_INET, optarg, &c->ip4.addrs[0].addr) &&
+			    !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addrs[0].addr) &&
+			    !IN4_IS_ADDR_BROADCAST(&c->ip4.addrs[0].addr) &&
+			    !IN4_IS_ADDR_LOOPBACK(&c->ip4.addrs[0].addr) &&
+			    !IN4_IS_ADDR_MULTICAST(&c->ip4.addrs[0].addr)) {
 				if (c->mode == MODE_PASTA)
 					c->ip4.no_copy_addrs = true;
 				break;
@@ -1836,8 +1855,8 @@ void conf(struct ctx *c, int argc, char **argv)
 			die("Invalid address: %s", optarg);
 			break;
 		case 'n':
-			c->ip4.prefix_len = conf_ip4_prefix(optarg);
-			if (c->ip4.prefix_len < 0)
+			c->ip4.addrs[0].prefix_len = conf_ip4_prefix(optarg);
+			if (c->ip4.addrs[0].prefix_len < 0)
 				die("Invalid netmask: %s", optarg);
 
 			break;
@@ -1984,9 +2003,9 @@ void conf(struct ctx *c, int argc, char **argv)
 
 	nl_sock_init(c, false);
 	if (!v6_only)
-		c->ifi4 = conf_ip4(ifi4, &c->ip4);
+		c->ifi4 = conf_ip4(ifi4, &c->ip4, c->pasta_conf_ns);
 	if (!v4_only)
-		c->ifi6 = conf_ip6(ifi6, &c->ip6);
+		c->ifi6 = conf_ip6(ifi6, &c->ip6, c->pasta_conf_ns);
 
 	if (c->ifi4 && c->mtu < IPV4_MIN_MTU) {
 		warn("MTU %"PRIu16" is too small for IPv4 (minimum %u)",
@@ -2125,7 +2144,7 @@ void conf(struct ctx *c, int argc, char **argv)
 	if (!c->ifi6) {
 		c->no_ndp = 1;
 		c->no_dhcpv6 = 1;
-	} else if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)) {
+	} else if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addrs[0].addr)) {
 		c->no_dhcpv6 = 1;
 	}
 
diff --git a/dhcp.c b/dhcp.c
index 6b9c2e3..46ef8e3 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -352,7 +352,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data)
 	reply.secs		= 0;
 	reply.flags		= m->flags;
 	reply.ciaddr		= m->ciaddr;
-	reply.yiaddr		= c->ip4.addr;
+	reply.yiaddr		= c->ip4.addrs[0].addr;
 	reply.siaddr		= 0;
 	reply.giaddr		= m->giaddr;
 	memcpy(&reply.chaddr,	m->chaddr,	sizeof(reply.chaddr));
@@ -404,7 +404,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data)
 
 	info("    from %s", eth_ntop(m->chaddr, macstr, sizeof(macstr)));
 
-	mask.s_addr = htonl(0xffffffff << (32 - c->ip4.prefix_len));
+	mask.s_addr = htonl(0xffffffff << (32 - c->ip4.addrs[0].prefix_len));
 	memcpy(opts[1].s,  &mask,                sizeof(mask));
 	memcpy(opts[3].s,  &c->ip4.guest_gw,     sizeof(c->ip4.guest_gw));
 	memcpy(opts[54].s, &c->ip4.our_tap_addr, sizeof(c->ip4.our_tap_addr));
@@ -412,7 +412,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data)
 	/* If the gateway is not on the assigned subnet, send an option 121
 	 * (Classless Static Routing) adding a dummy route to it.
 	 */
-	if ((c->ip4.addr.s_addr & mask.s_addr)
+	if ((c->ip4.addrs[0].addr.s_addr & mask.s_addr)
 	    != (c->ip4.guest_gw.s_addr & mask.s_addr)) {
 		/* a.b.c.d/32:0.0.0.0, 0:a.b.c.d */
 		opts[121].slen = 14;
@@ -469,7 +469,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data)
 	if (m->flags & FLAG_BROADCAST)
 		dst = in4addr_broadcast;
 	else
-		dst = c->ip4.addr;
+		dst = c->ip4.addrs[0].addr;
 
 	tap_udp4_send(c, c->ip4.our_tap_addr, 67, dst, 68, &reply, dlen);
 
diff --git a/dhcpv6.c b/dhcpv6.c
index e4df0db..7eae6a1 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -625,7 +625,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data,
 		if (mh->type == TYPE_CONFIRM && server_id)
 			return -1;
 
-		if (dhcpv6_ia_notonlink(data, &c->ip6.addr)) {
+		if (dhcpv6_ia_notonlink(data, &c->ip6.addrs[0].addr)) {
 
 			dhcpv6_send_ia_notonlink(c, data, &client_id_base,
 						 ntohs(client_id->l), mh->xid);
@@ -679,7 +679,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data,
 
 	tap_udp6_send(c, src, 547, tap_ip6_daddr(c, src), 546,
 		      mh->xid, &resp, n);
-	c->ip6.addr_seen = c->ip6.addr;
+	c->ip6.addr_seen = c->ip6.addrs[0].addr;
 
 	return 1;
 }
@@ -703,5 +703,5 @@ void dhcpv6_init(const struct ctx *c)
 	memcpy(resp_not_on_link.server_id.duid_lladdr,
 	       c->our_tap_mac, sizeof(c->our_tap_mac));
 
-	resp.ia_addr.addr	= c->ip6.addr;
+	resp.ia_addr.addr	= c->ip6.addrs[0].addr;
 }
diff --git a/fwd.c b/fwd.c
index 44a0e10..408af30 100644
--- a/fwd.c
+++ b/fwd.c
@@ -516,7 +516,7 @@ static bool fwd_guest_accessible4(const struct ctx *c,
 	/* For IPv4, addr_seen is initialised to addr, so is always a valid
 	 * address
 	 */
-	if (IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr) ||
+	if (IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addrs[0].addr) ||
 	    IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr_seen))
 		return false;
 
@@ -537,7 +537,7 @@ static bool fwd_guest_accessible6(const struct ctx *c,
 	if (IN6_IS_ADDR_LOOPBACK(addr))
 		return false;
 
-	if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addr))
+	if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addrs[0].addr))
 		return false;
 
 	/* For IPv6, addr_seen starts unspecified, because we don't know what LL
@@ -587,9 +587,9 @@ static void nat_outbound(const struct ctx *c, const union inany_addr *addr,
 	else if (inany_equals6(addr, &c->ip6.map_host_loopback))
 		*translated = inany_loopback6;
 	else if (inany_equals4(addr, &c->ip4.map_guest_addr))
-		*translated = inany_from_v4(c->ip4.addr);
+		*translated = inany_from_v4(c->ip4.addrs[0].addr);
 	else if (inany_equals6(addr, &c->ip6.map_guest_addr))
-		translated->a6 = c->ip6.addr;
+		translated->a6 = c->ip6.addrs[0].addr;
 	else
 		*translated = *addr;
 }
@@ -710,10 +710,10 @@ bool nat_inbound(const struct ctx *c, const union inany_addr *addr,
 		   inany_equals6(addr, &in6addr_loopback)) {
 		translated->a6 = c->ip6.map_host_loopback;
 	} else if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.map_guest_addr) &&
-		   inany_equals4(addr, &c->ip4.addr)) {
+		   inany_equals4(addr, &c->ip4.addrs[0].addr)) {
 		*translated = inany_from_v4(c->ip4.map_guest_addr);
 	} else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.map_guest_addr) &&
-		   inany_equals6(addr, &c->ip6.addr)) {
+		   inany_equals6(addr, &c->ip6.addrs[0].addr)) {
 		translated->a6 = c->ip6.map_guest_addr;
 	} else if (fwd_guest_accessible(c, addr)) {
 		*translated = *addr;
diff --git a/ip.h b/ip.h
index 5830b92..748cb1f 100644
--- a/ip.h
+++ b/ip.h
@@ -135,4 +135,30 @@ static const struct in_addr in4addr_broadcast = { 0xffffffff };
 #define IPV6_MIN_MTU		1280
 #endif
 
+/* Maximum number of addresses per address family */
+#define IP4_MAX_ADDRS		8
+#define IP6_MAX_ADDRS		16
+
+/**
+ * struct ip4_addr_entry - IPv4 address with prefix length
+ * @addr:		IPv4 address
+ * @prefix_len:		Prefix length (netmask bits)
+ */
+struct ip4_addr_entry {
+	struct in_addr addr;
+	int prefix_len;
+	int permanent;
+};
+
+/**
+ * struct ip6_addr_entry - IPv6 address with prefix length
+ * @addr:		IPv6 address
+ * @prefix_len:		Prefix length
+ */
+struct ip6_addr_entry {
+	struct in6_addr addr;
+	int prefix_len;
+	int permanent;
+};
+
 #endif /* IP_H */
diff --git a/ndp.c b/ndp.c
index eb9e313..868a234 100644
--- a/ndp.c
+++ b/ndp.c
@@ -257,7 +257,7 @@ static void ndp_ra(const struct ctx *c, const struct in6_addr *dst)
 			.valid_lifetime		= ~0U,
 			.pref_lifetime		= ~0U,
 		},
-		.prefix = c->ip6.addr,
+		.prefix = c->ip6.addrs[0].addr,
 		.source_ll = {
 			.header = {
 				.type		= OPT_SRC_L2_ADDR,
@@ -466,8 +466,8 @@ void ndp_send_init_req(const struct ctx *c)
 			.icmp6_solicited	= 0, /* Reserved */
 			.icmp6_override		= 0, /* Reserved */
 		},
-		.target_addr = c->ip6.addr
+		.target_addr = c->ip6.addrs[0].addr
 	};
 	debug("Sending initial NDP NS request for guest MAC address");
-	ndp_send(c, &c->ip6.addr, &ns, sizeof(ns));
+	ndp_send(c, &c->ip6.addrs[0].addr, &ns, sizeof(ns));
 }
diff --git a/passt.h b/passt.h
index 79d01dd..533f2cb 100644
--- a/passt.h
+++ b/passt.h
@@ -66,9 +66,9 @@ enum passt_modes {
 
 /**
  * struct ip4_ctx - IPv4 execution context
- * @addr:		IPv4 address assigned to guest
+ * @addrs:		IPv4 addresses assigned to guest
+ * @addr_count:		Number of addresses in addrs[] array
  * @addr_seen:		Latest IPv4 address seen as source from tap
- * @prefixlen:		IPv4 prefix length (netmask)
  * @guest_gw:		IPv4 gateway as seen by the guest
  * @map_host_loopback:	Outbound connections to this address are NATted to the
  *                      host's 127.0.0.1
@@ -85,9 +85,10 @@ enum passt_modes {
  */
 struct ip4_ctx {
 	/* PIF_TAP addresses */
-	struct in_addr addr;
+	struct ip4_addr_entry addrs[IP4_MAX_ADDRS];
+	int addr_count;
+
 	struct in_addr addr_seen;
-	int prefix_len;
 	struct in_addr guest_gw;
 	struct in_addr map_host_loopback;
 	struct in_addr map_guest_addr;
@@ -107,7 +108,8 @@ struct ip4_ctx {
 
 /**
  * struct ip6_ctx - IPv6 execution context
- * @addr:		IPv6 address assigned to guest
+ * @addrs:		IPv6 addresses assigned to guest
+ * @addr_count:		Number of addresses in addrs[] array
  * @addr_seen:		Latest IPv6 global/site address seen as source from tap
  * @addr_ll_seen:	Latest IPv6 link-local address seen as source from tap
  * @guest_gw:		IPv6 gateway as seen by the guest
@@ -126,7 +128,9 @@ struct ip4_ctx {
  */
 struct ip6_ctx {
 	/* PIF_TAP addresses */
-	struct in6_addr addr;
+	struct ip6_addr_entry addrs[IP6_MAX_ADDRS];
+	int addr_count;
+
 	struct in6_addr addr_seen;
 	struct in6_addr addr_ll_seen;
 	struct in6_addr guest_gw;
diff --git a/pasta.c b/pasta.c
index 674b554..49b393c 100644
--- a/pasta.c
+++ b/pasta.c
@@ -331,8 +331,8 @@ void pasta_ns_conf(struct ctx *c)
 			if (c->ip4.no_copy_addrs) {
 				rc = nl_addr_set(nl_sock_ns, c->pasta_ifi,
 						 AF_INET,
-						 &c->ip4.addr,
-						 c->ip4.prefix_len);
+						 &c->ip4.addrs[0].addr,
+						 c->ip4.addrs[0].prefix_len);
 			} else {
 				rc = nl_addr_dup(nl_sock, c->ifi4,
 						 nl_sock_ns, c->pasta_ifi,
@@ -378,10 +378,12 @@ void pasta_ns_conf(struct ctx *c)
 					  0, IFF_NOARP);
 
 			if (c->ip6.no_copy_addrs) {
-				if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)) {
+				struct in6_addr *a = &c->ip6.addrs[0].addr;
+
+				if (!IN6_IS_ADDR_UNSPECIFIED(a)) {
 					rc = nl_addr_set(nl_sock_ns,
-							 c->pasta_ifi, AF_INET6,
-							 &c->ip6.addr, 64);
+							 c->pasta_ifi,
+							 AF_INET6, a, 64);
 				}
 			} else {
 				rc = nl_addr_dup(nl_sock, c->ifi6,
diff --git a/tap.c b/tap.c
index e3ea61c..0b96cc1 100644
--- a/tap.c
+++ b/tap.c
@@ -951,8 +951,8 @@ resume:
 				c->ip6.addr_seen = *saddr;
 			}
 
-			if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr))
-				c->ip6.addr = *saddr;
+			if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addrs[0].addr))
+				c->ip6.addrs[0].addr = *saddr;
 		} else if (!IN6_IS_ADDR_UNSPECIFIED(saddr)){
 			c->ip6.addr_seen = *saddr;
 		}
diff --git a/util.h b/util.h
index f7a941f..4273e0d 100644
--- a/util.h
+++ b/util.h
@@ -401,4 +401,5 @@ static inline int wrap_getsockname(int sockfd, struct sockaddr *addr,
 #define PASST_MAXDNAME 254 /* 253 (RFC 1035) + 1 (the terminator) */
 void encode_domain_name(char *buf, const char *domain_name);
 
+
 #endif /* UTIL_H */
-- 
2.51.1