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 917025d299449e410c3cd62f29e78f750747e908..4ba7cf775e9b7b5dde9eda9fd111cf64e522aef5 100644 (file)
--- 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);