3 files changed, 16 insertions, 1 deletions
diff --git a/conf.c b/conf.c
index 6f86940..cd05adf 100644
--- a/conf.c
+++ b/conf.c
@@ -1254,7 +1254,9 @@ void conf(struct ctx *c, int argc, char **argv)
 	int name, ret;
 	uid_t uid;
 	gid_t gid;
-	
+
+	if (c->no_ipv6)
+		v4_only = true;
 
 	if (c->mode == MODE_PASTA)
 		c->no_dhcp_dns = c->no_dhcp_dns_search = 1;
@@ -1682,6 +1684,9 @@ void conf(struct ctx *c, int argc, char **argv)
 			v6_only = false;
 			break;
 		case '6':
+			if (c->no_ipv6)
+				die("IPv6 not available but --ipv6-only given");
+
 			v6_only = true;
 			v4_only = false;
 			break;
diff --git a/passt.h b/passt.h
index 1726965..c5f51d1 100644
--- a/passt.h
+++ b/passt.h
@@ -211,6 +211,7 @@ struct ip6_ctx {
  * @low_wmem:		Low probed net.core.wmem_max
  * @low_rmem:		Low probed net.core.rmem_max
  * @no_bindtodevice:	Unprivileged SO_BINDTODEVICE not available
+ * @no_ipv6:		IPv6 sockets not available
  * @vdev:		vhost-user device
  * @device_state_fd:	Device state migration channel
  * @device_state_result: Device state migration result
@@ -296,6 +297,7 @@ struct ctx {
 	int low_wmem;
 	int low_rmem;
 	int no_bindtodevice;
+	bool no_ipv6;
 
 	struct vu_dev *vdev;
 
diff --git a/util.c b/util.c
index b64c29e..fe0aab9 100644
--- a/util.c
+++ b/util.c
@@ -334,6 +334,14 @@ void sock_probe_features(struct ctx *c)
 		c->no_bindtodevice = 1;
 	}
 
+	/* Check if IPv6 sockets are usable */
+	close(s);
+	s = socket(AF_INET6, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	if (s < 0) {
+		c->no_ipv6 = true;
+		return;
+	}
+
 	close(s);
 }