allow lxc.network.pair to specify host-side name for veth interface

src/lxc/conf.c

@@ -829,14 +829,19 @@ int lxc_conf_init(struct lxc_conf *conf)
 
 static int instanciate_veth(struct lxc_netdev *netdev)
 {
-	char veth1[IFNAMSIZ];
+	char veth1buf[IFNAMSIZ], *veth1;
 	char veth2[IFNAMSIZ];
 	int ret = -1;
 
-	snprintf(veth1, sizeof(veth1), "vethXXXXXX");
-	snprintf(veth2, sizeof(veth2), "vethXXXXXX");
+	if (netdev->pair)
+		veth1 = netdev->pair;
+	else {
+		snprintf(veth1buf, sizeof(veth1buf), "vethXXXXXX");
+		mktemp(veth1buf);
+		veth1 = veth1buf;
+	}
 
-	mktemp(veth1);
+	snprintf(veth2, sizeof(veth2), "vethXXXXXX");
 	mktemp(veth2);
 
 	if (!strlen(veth1) || !strlen(veth2)) {

src/lxc/conf.h

@@ -73,6 +73,7 @@ struct lxc_route6 {
  * Defines a structure to configure a network device
  * @link   : lxc.network.link, name of bridge or host iface to attach if any
  * @name   : lxc.network.name, name of iface on the container side
+ * @pair   : lxc.network.pair, name of host-side iface in case of veth etc
  * @flags  : flag of the network device (IFF_UP, ... )
  * @ipv4   : a list of ipv4 addresses to be set on the network device
  * @ipv6   : a list of ipv6 addresses to be set on the network device
@@ -83,6 +84,7 @@ struct lxc_netdev {
 	int ifindex;
 	char *link;
 	char *name;
+	char *pair;
 	char *hwaddr;
 	char *mtu;
 	struct lxc_list ipv4;

src/lxc/confile.c

@@ -49,6 +49,7 @@ static int config_network_type(const char *, char *, struct lxc_conf *);
 static int config_network_flags(const char *, char *, struct lxc_conf *);
 static int config_network_link(const char *, char *, struct lxc_conf *);
 static int config_network_name(const char *, char *, struct lxc_conf *);
+static int config_network_pair(const char *, char *, struct lxc_conf *);
 static int config_network_hwaddr(const char *, char *, struct lxc_conf *);
 static int config_network_mtu(const char *, char *, struct lxc_conf *);
 static int config_network_ipv4(const char *, char *, struct lxc_conf *);
@@ -73,6 +74,7 @@ static struct config config[] = {
 	{ "lxc.network.flags",  config_network_flags  },
 	{ "lxc.network.link",   config_network_link   },
 	{ "lxc.network.name",   config_network_name   },
+	{ "lxc.network.pair",   config_network_pair   },
 	{ "lxc.network.hwaddr", config_network_hwaddr },
 	{ "lxc.network.mtu",    config_network_mtu    },
 	{ "lxc.network.ipv4",   config_network_ipv4   },
@@ -221,6 +223,18 @@ static int config_network_name(const char *key, char *value,
 	return network_ifname(&netdev->name, value);
 }
 
+static int config_network_pair(const char *key, char *value,
+			       struct lxc_conf *lxc_conf)
+{
+	struct lxc_netdev *netdev;
+
+	netdev = network_netdev(key, value, &lxc_conf->network);
+	if (!netdev)
+		return -1;
+
+	return network_ifname(&netdev->pair, value);
+}
+
 static int config_network_hwaddr(const char *key, char *value,
 				 struct lxc_conf *lxc_conf)
 {