From 8ca907a3f0a095691cdaf56ad610fd802df88146 Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Thu, 23 Feb 2023 13:32:30 +0000
Subject: [PATCH] conf: Split add_dns{4,6}() out of get_dns()

The logic handling which resolvers we add, and whether to add them,
is getting rather cramped in get_dns(): split it into separate
functions.

No functional changes intended.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
 conf.c | 86 ++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 51 insertions(+), 35 deletions(-)

diff --git a/conf.c b/conf.c
index 4dc0660..ed25e35 100644
--- a/conf.c
+++ b/conf.c
@@ -382,6 +382,53 @@ bind_fail:
 	die("Failed to bind any port for '-%c %s', exiting", optname, optarg);
 }
 
+/**
+ * add_dns4() - Possibly add the IPv4 address of a DNS resolver to configuration
+ * @c:		Execution context
+ * @addr:	Address found in /etc/resolv.conf
+ * @conf:	Pointer to reference of current entry in array of IPv4 resolvers
+ */
+static void add_dns4(struct ctx *c, struct in_addr *addr, struct in_addr **conf)
+{
+	/* Guest or container can only access local addresses via redirect */
+	if (IN4_IS_ADDR_LOOPBACK(addr)) {
+		if (!c->no_map_gw) {
+			**conf = c->ip4.gw;
+			(*conf)++;
+		}
+	} else {
+		**conf = *addr;
+		(*conf)++;
+	}
+
+	if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_host))
+		c->ip4.dns_host = *addr;
+}
+
+/**
+ * add_dns6() - Possibly add the IPv6 address of a DNS resolver to configuration
+ * @c:		Execution context
+ * @addr:	Address found in /etc/resolv.conf
+ * @conf:	Pointer to reference of current entry in array of IPv6 resolvers
+ */
+static void add_dns6(struct ctx *c,
+		     struct in6_addr *addr, struct in6_addr **conf)
+{
+	/* Guest or container can only access local addresses via redirect */
+	if (IN6_IS_ADDR_LOOPBACK(addr)) {
+		if (!c->no_map_gw) {
+			memcpy(*conf, &c->ip6.gw, sizeof(**conf));
+			(*conf)++;
+		}
+	} else {
+		memcpy(*conf, addr, sizeof(**conf));
+		(*conf)++;
+	}
+
+	if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_host))
+		c->ip6.dns_host = *addr;
+}
+
 /**
  * get_dns() - Get nameserver addresses from local /etc/resolv.conf
  * @c:		Execution context
@@ -420,44 +467,13 @@ static void get_dns(struct ctx *c)
 
 			if (!dns4_set &&
 			    dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) - 1
-			    && inet_pton(AF_INET, p + 1, &dns4_tmp)) {
-				/* Guest or container can only access local
-				 * addresses via local redirect
-				 */
-				if (IN4_IS_ADDR_LOOPBACK(&dns4_tmp)) {
-					if (!c->no_map_gw) {
-						*dns4 = c->ip4.gw;
-						dns4++;
-					}
-				} else {
-					*dns4 = dns4_tmp;
-					dns4++;
-				}
-
-				if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_host))
-					c->ip4.dns_host = dns4_tmp;
-			}
+			    && inet_pton(AF_INET, p + 1, &dns4_tmp))
+				add_dns4(c, &dns4_tmp, &dns4);
 
 			if (!dns6_set &&
 			    dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) - 1
-			    && inet_pton(AF_INET6, p + 1, &dns6_tmp)) {
-				/* Guest or container can only access local
-				 * addresses via local redirect
-				 */
-				if (IN6_IS_ADDR_LOOPBACK(&dns6_tmp)) {
-					if (!c->no_map_gw) {
-						memcpy(dns6, &c->ip6.gw,
-						       sizeof(*dns6));
-						dns6++;
-					}
-				} else {
-					memcpy(dns6, &dns6_tmp, sizeof(*dns6));
-					dns6++;
-				}
-
-				if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_host))
-					c->ip6.dns_host = dns6_tmp;
-			}
+			    && inet_pton(AF_INET6, p + 1, &dns6_tmp))
+				add_dns6(c, &dns6_tmp, &dns6);
 		} else if (!dnss_set && strstr(line, "search ") == line &&
 			   s == c->dns_search) {
 			end = strpbrk(line, "\n");