[PATCH v2 8/9] conf: Don't defer handling of --dns option

[David Gibson <david@gibson.dropbear.id.au>]

For various reasons we make several passes through our command line options
in conf().  First there's the main pass, then some supplemental passes for
options that couldn't be handled in the initial pass.

The --dns / -D option is handled in the second pass since f6d5a5239264
("conf: Delay handling -D option until after addresses are configured").
The reason was that it called add_dns[46]() which relied on the gateway
address already being configured which needed the first pass to complete.

However, since 0b25cac94eca ("conf: Treat --dns addresses as guest visible
addresses") that reason no longer applies - add_dns[46]() do nothing but
update tables in a very simple way.

So, move the --dns handling back into the main parsing pass.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 conf.c | 80 ++++++++++++++++++++++++++++------------------------------
 1 file changed, 39 insertions(+), 41 deletions(-)

diff --git a/conf.c b/conf.c
index 96aa506d..ffbd403d 100644
--- a/conf.c
+++ b/conf.c
@@ -2001,9 +2001,44 @@ void conf(struct ctx *c, int argc, char **argv)
 			break;
 		case 't':
 		case 'u':
-		case 'D':
 			/* Handle these later, once addresses are configured */
 			break;
+		case 'D': {
+			struct in6_addr dns6_tmp;
+			struct in_addr dns4_tmp;
+
+			if (!strcmp(optarg, "none")) {
+				c->no_dns = 1;
+
+				dns4_idx = 0;
+				memset(c->ip4.dns, 0, sizeof(c->ip4.dns));
+				c->ip4.dns[0]    = (struct in_addr){ 0 };
+				c->ip4.dns_match = (struct in_addr){ 0 };
+				c->ip4.dns_host  = (struct in_addr){ 0 };
+
+				dns6_idx = 0;
+				memset(c->ip6.dns, 0, sizeof(c->ip6.dns));
+				c->ip6.dns_match = (struct in6_addr){ 0 };
+				c->ip6.dns_host  = (struct in6_addr){ 0 };
+
+				continue;
+			}
+
+			c->no_dns = 0;
+
+			if (inet_pton(AF_INET, optarg, &dns4_tmp)) {
+				dns4_idx += add_dns4(c, &dns4_tmp, dns4_idx);
+				continue;
+			}
+
+			if (inet_pton(AF_INET6, optarg, &dns6_tmp)) {
+				dns6_idx += add_dns6(c, &dns6_tmp, dns6_idx);
+				continue;
+			}
+
+			die("Cannot use DNS address %s", optarg);
+		}
+			break;
 		case 'T':
 		case 'U':
 			if (c->mode != MODE_PASTA)
@@ -2117,53 +2152,16 @@ void conf(struct ctx *c, int argc, char **argv)
 	if (c->ifi4 && IN4_IS_ADDR_UNSPECIFIED(&c->ip4.guest_gw))
 		c->no_dhcp = 1;
 
-	/* Inbound port options and DNS can be parsed now, after IPv4/IPv6
-	 * settings
-	 */
+	/* Inbound port options can be parsed now, after IPv4/IPv6 settings */
 	fwd_probe_ephemeral();
 	optind = 0;
 	do {
 		name = getopt_long(argc, argv, optstring, options, NULL);
 
-		if (name == 't') {
+		if (name == 't')
 			conf_ports(c, name, optarg, &c->fwd_in, &tcp_in_mode);
-		} else if (name == 'u') {
+		else if (name == 'u')
 			conf_ports(c, name, optarg, &c->fwd_in, &udp_in_mode);
-		} else if (name == 'D') {
-			struct in6_addr dns6_tmp;
-			struct in_addr dns4_tmp;
-
-			if (!strcmp(optarg, "none")) {
-				c->no_dns = 1;
-
-				dns4_idx = 0;
-				memset(c->ip4.dns, 0, sizeof(c->ip4.dns));
-				c->ip4.dns[0]    = (struct in_addr){ 0 };
-				c->ip4.dns_match = (struct in_addr){ 0 };
-				c->ip4.dns_host  = (struct in_addr){ 0 };
-
-				dns6_idx = 0;
-				memset(c->ip6.dns, 0, sizeof(c->ip6.dns));
-				c->ip6.dns_match = (struct in6_addr){ 0 };
-				c->ip6.dns_host  = (struct in6_addr){ 0 };
-
-				continue;
-			}
-
-			c->no_dns = 0;
-
-			if (inet_pton(AF_INET, optarg, &dns4_tmp)) {
-				dns4_idx += add_dns4(c, &dns4_tmp, dns4_idx);
-				continue;
-			}
-
-			if (inet_pton(AF_INET6, optarg, &dns6_tmp)) {
-				dns6_idx += add_dns6(c, &dns6_tmp, dns6_idx);
-				continue;
-			}
-
-			die("Cannot use DNS address %s", optarg);
-		}
 	} while (name != -1);
 
 	if (c->mode == MODE_PASTA)
-- 
2.53.0