[PATCH v2 6/9] 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.
- If a prefix length is to be added, it has to be done in CIDR format,
  except for the very first address.
- We configure all indicated addresses in the namespace interface.

Signed-off-by: Jon Maloy <jmaloy@redhat.com>

---
v2: Adapted to previous code changes
---
 conf.c  | 42 +++++++++++++++++++++++++++++-------------
 pasta.c | 24 ++++++++++++++++++------
 2 files changed, 47 insertions(+), 19 deletions(-)

diff --git a/conf.c b/conf.c
index 3ecd1a0..32a754d 100644
--- a/conf.c
+++ b/conf.c
@@ -789,7 +789,7 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
 
 	ip4->our_tap_addr = ip4->guest_gw;
 
-	if (inany_is_unspecified(&ip4->addrs[0].addr))
+	if (!ip4->addr_count)
 		return 0;
 
 	return ifi;
@@ -858,8 +858,7 @@ 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.a6) ||
-	    IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll))
+	if (!ip6->addr_count || IN6_IS_ADDR_UNSPECIFIED(&ip6->our_tap_ll))
 		return 0;
 
 	return ifi;
@@ -951,9 +950,11 @@ 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[/PREFIXLEN]\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"
@@ -1882,6 +1883,7 @@ void conf(struct ctx *c, int argc, char **argv)
 			union inany_addr addr;
 			const struct in_addr *a4;
 			int prefix_len = 0;
+			unsigned int i;
 			int af;
 
 			af = conf_addr_prefix_len(optarg, &addr, &prefix_len);
@@ -1893,9 +1895,15 @@ void conf(struct ctx *c, int argc, char **argv)
 				die("Invalid address: %s", optarg);
 
 			if (af == AF_INET6) {
-				c->ip6.addrs[0].addr.a6 = addr.a6;
-				c->ip6.addrs[0].flags |= INANY_ADDR_CONFIGURED;
-				c->ip6.addr_count = 1;
+				i = c->ip6.addr_count;
+
+				if (i >= IP6_MAX_ADDRS)
+					die("Too many IPv6 addresses");
+
+				c->ip6.addrs[i].addr.a6 = addr.a6;
+				c->ip6.addrs[i].prefix_len = prefix_len;
+				c->ip6.addrs[i].flags = INANY_ADDR_CONFIGURED;
+				c->ip6.addr_count++;
 				if (c->mode == MODE_PASTA)
 					c->ip6.no_copy_addrs = true;
 				break;
@@ -1904,10 +1912,15 @@ void conf(struct ctx *c, int argc, char **argv)
 			a4 = inany_v4(&addr);
 
 			if (af == AF_INET && a4) {
-				c->ip4.addrs[0].addr = inany_from_v4(*a4);
-				c->ip4.addrs[0].flags |= INANY_ADDR_CONFIGURED;
-				c->ip4.addr_count = 1;
-				if (prefix_len) {
+				i = c->ip4.addr_count;
+
+				if (i >= IP4_MAX_ADDRS)
+					die("Too many IPv4 addresses");
+
+				c->ip4.addrs[i].addr = inany_from_v4(*a4);
+				c->ip4.addrs[i].prefix_len = prefix_len;
+				c->ip4.addrs[i].flags = INANY_ADDR_CONFIGURED;
+				if (i == 0 && prefix_len) {
 					if (prefix_from_opt)
 						die("Can't mix CIDR with -n");
 					prefix_from_cidr = true;
@@ -1915,6 +1928,9 @@ void conf(struct ctx *c, int argc, char **argv)
 					prefix_len = ip4_default_prefix_len(a4);
 				}
 				c->ip4.addrs[0].prefix_len = prefix_len;
+				c->ip4.addr_count++;
+				if (c->mode == MODE_PASTA)
+					c->ip4.no_copy_addrs = true;
 				break;
 			}
 
@@ -2217,7 +2233,7 @@ 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.a6)) {
+	} else if (!c->ip6.addr_count) {
 		c->no_dhcpv6 = 1;
 	}
 
diff --git a/pasta.c b/pasta.c
index 1bb3dd0..27ce6a7 100644
--- a/pasta.c
+++ b/pasta.c
@@ -338,10 +338,16 @@ 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,
-						 inany_v4(&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,
+							 inany_v4(&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,
@@ -387,12 +393,18 @@ 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.a6;
+				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.a6;
+					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,
-- 
2.52.0