[RFC 03/12] conf: Allow multiple -a/--address options per address family

[Jon Maloy <jmaloy@redhat.com>]

We enable configuration of multiple IPv4 and IPv6 addresses by allowing
repeated use of the -a/--address option.

- We update option parsing to append addresses to the addrs[] array.

- Each address specified via -a does initially get a class-based default
  prefix.

- If no -a option is given, address and prefix are inherited from
  the template interface, just like now.

- The -n/--netmask option applies only to the first address, in addrs[0].

- We configure all indicated addresses in the namespace interface.

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 conf.c  | 74 ++++++++++++++++++++++++++++++++++++++-------------------
 pasta.c | 24 ++++++++++++++-----
 2 files changed, 68 insertions(+), 30 deletions(-)

diff --git a/conf.c b/conf.c
index 31acc20..e9f217b 100644
--- a/conf.c
+++ b/conf.c
@@ -741,7 +741,7 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4,
 
 	ip4->our_tap_addr = ip4->guest_gw;
 
-	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addrs[0].addr))
+	if (!ip4->addr_count)
 		return 0;
 
 	return ifi;
@@ -756,6 +756,7 @@ static void conf_ip4_local(struct ip4_ctx *ip4)
 	ip4->addr_seen = ip4->addrs[0].addr = IP4_LL_GUEST_ADDR;
 	ip4->our_tap_addr = ip4->guest_gw = IP4_LL_GUEST_GW;
 	ip4->addrs[0].prefix_len = IP4_LL_PREFIX_LEN;
+	ip4->addr_count = 1;
 
 	ip4->no_copy_addrs = ip4->no_copy_routes = true;
 }
@@ -810,8 +811,7 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6,
 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->guest_gw))
 		ip6->our_tap_ll = ip6->guest_gw;
 
-	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->addrs[0].addr) ||
-	    IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll))
+	if (!ip6->addr_count || IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll))
 		return 0;
 
 	return ifi;
@@ -903,9 +903,11 @@ static void usage(const char *name, FILE *f, int status)
 		"    default: 65520: maximum 802.3 MTU minus 802.3 header\n"
 		"                    length, rounded to 32 bits (IPv4 words)\n"
 		"  -a, --address ADDR	Assign IPv4 or IPv6 address ADDR\n"
-		"    can be specified zero to two times (for IPv4 and IPv6)\n"
+		"    can be specified multiple times (limit: %d IPv4, %d IPv6)\n"
 		"    default: use addresses from interface with default route\n"
-		"  -n, --netmask MASK	Assign IPv4 MASK, dot-decimal or bits\n"
+		"  -n, --netmask MASK	Assign IPv4 MASK, dot-decimal or bits\n",
+		IP4_MAX_ADDRS, IP6_MAX_ADDRS);
+	FPRINTF(f,
 		"    default: netmask from matching address on the host\n"
 		"  -M, --mac-addr ADDR	Use source MAC address ADDR\n"
 		"    default: 9a:55:9a:55:9a:55 (locally administered)\n"
@@ -1159,9 +1161,11 @@ static void conf_print(const struct ctx *c)
 				     (32 - c->ip4.addrs[0].prefix_len));
 
 			info("DHCP:");
-			info("    assign: %s",
-			     inet_ntop(AF_INET, &c->ip4.addrs[0].addr,
-				       buf4, sizeof(buf4)));
+			for (i = 0; i < (int)c->ip4.addr_count; i++) {
+				info("    assign: %s",
+				     inet_ntop(AF_INET, &c->ip4.addrs[i].addr,
+					       buf4, sizeof(buf4)));
+			}
 			info("    mask: %s",
 			     inet_ntop(AF_INET, &mask,        buf4, sizeof(buf4)));
 			info("    router: %s",
@@ -1198,9 +1202,11 @@ static void conf_print(const struct ctx *c)
 		else
 			goto dns6;
 
-		info("    assign: %s",
-		     inet_ntop(AF_INET6, &c->ip6.addrs[0].addr,
-			       buf6, sizeof(buf6)));
+		for (i = 0; i < (int)c->ip6.addr_count; i++) {
+			info("    assign: %s",
+			     inet_ntop(AF_INET6, &c->ip6.addrs[i].addr,
+				       buf6, sizeof(buf6)));
+		}
 		info("    router: %s",
 		     inet_ntop(AF_INET6, &c->ip6.guest_gw, buf6, sizeof(buf6)));
 		info("    our link-local: %s",
@@ -1517,6 +1523,8 @@ void conf(struct ctx *c, int argc, char **argv)
 	struct fqdn *dnss = c->dns_search;
 	unsigned int ifi4 = 0, ifi6 = 0;
 	const char *logfile = NULL;
+	struct in6_addr addr6;
+	struct in_addr addr4;
 	size_t logsize = 0;
 	char *runas = NULL;
 	long fd_tap_opt;
@@ -1821,23 +1829,41 @@ void conf(struct ctx *c, int argc, char **argv)
 			break;
 		}
 		case 'a':
-			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 (inet_pton(AF_INET6, optarg, &addr6) &&
+			    !IN6_IS_ADDR_UNSPECIFIED(&addr6) &&
+			    !IN6_IS_ADDR_LOOPBACK(&addr6) &&
+			    !IN6_IS_ADDR_V4MAPPED(&addr6) &&
+			    !IN6_IS_ADDR_V4COMPAT(&addr6) &&
+			    !IN6_IS_ADDR_MULTICAST(&addr6)) {
+				unsigned int i = c->ip6.addr_count;
+
+				if (i >= IP6_MAX_ADDRS)
+					die("Too many IPv6 addresses");
+
+				c->ip6.addrs[i].addr = addr6;
+				c->ip6.addrs[i].prefix_len = 64;
+				c->ip6.addrs[i].permanent = true;
+				c->ip6.addr_count++;
 				if (c->mode == MODE_PASTA)
 					c->ip6.no_copy_addrs = true;
 				break;
 			}
 
-			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 (inet_pton(AF_INET, optarg, &addr4) &&
+			    !IN4_IS_ADDR_UNSPECIFIED(&addr4) &&
+			    !IN4_IS_ADDR_BROADCAST(&addr4) &&
+			    !IN4_IS_ADDR_LOOPBACK(&addr4) &&
+			    !IN4_IS_ADDR_MULTICAST(&addr4)) {
+				unsigned int i = c->ip4.addr_count;
+
+				if (i >= IP4_MAX_ADDRS)
+					die("Too many IPv4 addresses");
+
+				c->ip4.addrs[i].addr = addr4;
+				c->ip4.addrs[i].prefix_len =
+					ip4_default_prefix_len(&addr4);
+				c->ip4.addrs[i].permanent = true;
+				c->ip4.addr_count++;
 				if (c->mode == MODE_PASTA)
 					c->ip4.no_copy_addrs = true;
 				break;
@@ -2135,7 +2161,7 @@ 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.addrs[0].addr)) {
+	} else if (!c->ip6.addr_count) {
 		c->no_dhcpv6 = 1;
 	}
 
diff --git a/pasta.c b/pasta.c
index 49b393c..fe2908f 100644
--- a/pasta.c
+++ b/pasta.c
@@ -329,10 +329,16 @@ void pasta_ns_conf(struct ctx *c)
 
 		if (c->ifi4) {
 			if (c->ip4.no_copy_addrs) {
-				rc = nl_addr_set(nl_sock_ns, c->pasta_ifi,
-						 AF_INET,
-						 &c->ip4.addrs[0].addr,
-						 c->ip4.addrs[0].prefix_len);
+				int i;
+
+				for (i = 0; i < c->ip4.addr_count; i++) {
+					rc = nl_addr_set(nl_sock_ns,
+							 c->pasta_ifi, AF_INET,
+							 &c->ip4.addrs[i].addr,
+							 c->ip4.addrs[i].prefix_len);
+					if (rc < 0)
+						break;
+				}
 			} else {
 				rc = nl_addr_dup(nl_sock, c->ifi4,
 						 nl_sock_ns, c->pasta_ifi,
@@ -378,12 +384,18 @@ void pasta_ns_conf(struct ctx *c)
 					  0, IFF_NOARP);
 
 			if (c->ip6.no_copy_addrs) {
-				struct in6_addr *a = &c->ip6.addrs[0].addr;
+				struct in6_addr *a;
+				int i;
 
-				if (!IN6_IS_ADDR_UNSPECIFIED(a)) {
+				for (i = 0; i < c->ip6.addr_count; i++) {
+					a = &c->ip6.addrs[i].addr;
+					if (IN6_IS_ADDR_UNSPECIFIED(a))
+						continue;
 					rc = nl_addr_set(nl_sock_ns,
 							 c->pasta_ifi,
 							 AF_INET6, a, 64);
+					if (rc < 0)
+						break;
 				}
 			} else {
 				rc = nl_addr_dup(nl_sock, c->ifi6,
-- 
2.51.1