From: Roy Marples <roy@marples.name>
Date: Sat, 25 Jul 2020 13:22:18 +0000 (+0100)
Subject: options: open an address socket to detect if inet6 is available
X-Git-Tag: v9.2.0~38
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=465198ad6453f68eb1223615d4ab5deefc0294cf;p=thirdparty%2Fdhcpcd.git

options: open an address socket to detect if inet6 is available

This should silence dhcpcd warnings if IPv6 is compiled out.
Do the same for IPv4, although that's highly unlikely as
it's kind of required for some interface ioctls.
---

diff --git a/src/if-options.c b/src/if-options.c
index 917025d2..4ba7cf77 100644
--- a/src/if-options.c
+++ b/src/if-options.c
@@ -59,6 +59,8 @@
 #define	SET_CONFIG_BLOCK(ifo)	((ifo)->options |= DHCPCD_FORKED)
 #define	CLEAR_CONFIG_BLOCK(ifo)	((ifo)->options &= ~DHCPCD_FORKED)
 
+static unsigned long long default_options;
+
 const struct option cf_options[] = {
 	{"background",      no_argument,       NULL, 'b'},
 	{"script",          required_argument, NULL, 'c'},
@@ -2332,18 +2334,30 @@ read_config(struct dhcpcd_ctx *ctx,
 	/* Seed our default options */
 	if ((ifo = default_config(ctx)) == NULL)
 		return NULL;
-	ifo->options |= DHCPCD_DAEMONISE | DHCPCD_GATEWAY;
-#ifdef PLUGIN_DEV
-	ifo->options |= DHCPCD_DEV;
-#endif
+	if (default_options == 0) {
+		default_options |= DHCPCD_DAEMONISE | DHCPCD_GATEWAY;
 #ifdef INET
-	ifo->options |= DHCPCD_IPV4 | DHCPCD_ARP | DHCPCD_DHCP | DHCPCD_IPV4LL;
+		skip = socket(PF_INET, SOCK_DGRAM, 0);
+		if (skip != -1) {
+			close(skip);
+			default_options |= DHCPCD_IPV4 | DHCPCD_ARP |
+			    DHCPCD_DHCP | DHCPCD_IPV4LL;
+		}
 #endif
 #ifdef INET6
-	ifo->options |= DHCPCD_IPV6 | DHCPCD_IPV6RS;
-	ifo->options |= DHCPCD_IPV6RA_AUTOCONF | DHCPCD_IPV6RA_REQRDNSS;
-	ifo->options |= DHCPCD_DHCP6;
+		skip = socket(PF_INET6, SOCK_DGRAM, 0);
+		if (skip != -1) {
+			close(skip);
+			default_options |= DHCPCD_IPV6 | DHCPCD_IPV6RS |
+			    DHCPCD_IPV6RA_AUTOCONF | DHCPCD_IPV6RA_REQRDNSS |
+			    DHCPCD_DHCP6;
+		}
+#endif
+#ifdef PLUGIN_DEV
+		default_options |= DHCPCD_DEV;
 #endif
+	}
+	ifo->options |= default_options;
 
 	CLEAR_CONFIG_BLOCK(ifo);