Make lxc-user-nic use mkifname

src/lxc/conf.c

@@ -34,12 +34,6 @@
 #include <sys/syscall.h>
 #include <time.h>
 
-#if HAVE_IFADDRS_H
-#include <ifaddrs.h>
-#else
-#include <../include/ifaddrs.h>
-#endif
-
 #if HAVE_PTY_H
 #include <pty.h>
 #else
@@ -280,74 +274,6 @@ static struct caps_opt caps_opt[] = {
 static struct caps_opt caps_opt[] = {};
 #endif
 
-static char padchar[] =
-"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-
-static char *mkifname(char *template)
-{
-	char *name = NULL;
-	int i = 0;
-	FILE *urandom;
-	unsigned int seed;
-	struct ifaddrs *ifaddr, *ifa;
-	int ifexists = 0;
-
-	/* Get all the network interfaces */
-	getifaddrs(&ifaddr);
-
-	/* Initialize the random number generator */
-	process_lock();
-	urandom = fopen ("/dev/urandom", "r");
-	process_unlock();
-	if (urandom != NULL) {
-		if (fread (&seed, sizeof(seed), 1, urandom) <= 0)
-			seed = time(0);
-		process_lock();
-		fclose(urandom);
-		process_unlock();
-	}
-	else
-		seed = time(0);
-
-#ifndef HAVE_RAND_R
-	srand(seed);
-#endif
-
-	/* Generate random names until we find one that doesn't exist */
-	while(1) {
-		ifexists = 0;
-		name = strdup(template);
-
-		if (name == NULL)
-			return NULL;
-
-		for (i = 0; i < strlen(name); i++) {
-			if (name[i] == 'X') {
-#ifdef HAVE_RAND_R
-				name[i] = padchar[rand_r(&seed) % (strlen(padchar) - 1)];
-#else
-				name[i] = padchar[rand() % (strlen(padchar) - 1)];
-#endif
-			}
-		}
-
-		for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
-			if (strcmp(ifa->ifa_name, name) == 0) {
-				ifexists = 1;
-				break;
-			}
-		}
-
-		if (ifexists == 0)
-			break;
-
-		free(name);
-	}
-
-	freeifaddrs(ifaddr);
-	return name;
-}
-
 static int run_buffer(char *buffer)
 {
 	FILE *f;
@@ -2668,7 +2594,7 @@ static int instanciate_veth(struct lxc_handler *handler, struct lxc_netdev *netd
 			ERROR("veth1 name too long");
 			return -1;
 		}
-		veth1 = mkifname(veth1buf);
+		veth1 = lxc_mkifname(veth1buf);
 		if (!veth1) {
 			ERROR("failed to allocate a temporary name");
 			return -1;
@@ -2678,7 +2604,7 @@ static int instanciate_veth(struct lxc_handler *handler, struct lxc_netdev *netd
 	}
 
 	snprintf(veth2buf, sizeof(veth2buf), "vethXXXXXX");
-	veth2 = mkifname(veth2buf);
+	veth2 = lxc_mkifname(veth2buf);
 	if (!veth2) {
 		ERROR("failed to allocate a temporary name");
 		goto out_delete;
@@ -2787,7 +2713,7 @@ static int instanciate_macvlan(struct lxc_handler *handler, struct lxc_netdev *n
 	if (err >= sizeof(peerbuf))
 		return -1;
 
-	peer = mkifname(peerbuf);
+	peer = lxc_mkifname(peerbuf);
 	if (!peer) {
 		ERROR("failed to make a temporary name");
 		return -1;

src/lxc/lxc_user_nic.c

@@ -266,20 +266,16 @@ out_del:
 
 /*
  * Get a new nic.
- * *dest will container the name (lxcuser-%d) which is attached
+ * *dest will container the name (vethXXXXXX) which is attached
  * on the host to the lxc bridge
  */
 static void get_new_nicname(char **dest, char *br, int pid, char **cnic)
 {
-	int i = 0;
-	// TODO - speed this up.  For large installations we won't
-	// want n stats for every nth container startup.
-	while (1) {
-		sprintf(*dest, "lxcuser-%d", i);
-		if (!nic_exists(*dest) && create_nic(*dest, br, pid, cnic))
-			return;
-		i++;
-	}
+	char template[IFNAMSIZ];
+	snprintf(template, sizeof(template), "vethXXXXXX");
+	*dest = lxc_mkifname(template);
+
+	create_nic(*dest, br, pid, cnic);
 }
 
 static bool get_nic_from_line(char *p, char **nic)

src/lxc/network.c

@@ -50,6 +50,12 @@
 #include "conf.h"
 #include "lxclock.h"
 
+#if HAVE_IFADDRS_H
+#include <ifaddrs.h>
+#else
+#include <../include/ifaddrs.h>
+#endif
+
 #ifndef IFLA_LINKMODE
 #  define IFLA_LINKMODE 17
 #endif
@@ -1108,6 +1114,74 @@ const char *lxc_net_type_to_str(int type)
 	return lxc_network_types[type];
 }
 
+static char padchar[] =
+"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+char *lxc_mkifname(char *template)
+{
+	char *name = NULL;
+	int i = 0;
+	FILE *urandom;
+	unsigned int seed;
+	struct ifaddrs *ifaddr, *ifa;
+	int ifexists = 0;
+
+	/* Get all the network interfaces */
+	getifaddrs(&ifaddr);
+
+	/* Initialize the random number generator */
+	process_lock();
+	urandom = fopen ("/dev/urandom", "r");
+	process_unlock();
+	if (urandom != NULL) {
+		if (fread (&seed, sizeof(seed), 1, urandom) <= 0)
+			seed = time(0);
+		process_lock();
+		fclose(urandom);
+		process_unlock();
+	}
+	else
+		seed = time(0);
+
+#ifndef HAVE_RAND_R
+	srand(seed);
+#endif
+
+	/* Generate random names until we find one that doesn't exist */
+	while(1) {
+		ifexists = 0;
+		name = strdup(template);
+
+		if (name == NULL)
+			return NULL;
+
+		for (i = 0; i < strlen(name); i++) {
+			if (name[i] == 'X') {
+#ifdef HAVE_RAND_R
+				name[i] = padchar[rand_r(&seed) % (strlen(padchar) - 1)];
+#else
+				name[i] = padchar[rand() % (strlen(padchar) - 1)];
+#endif
+			}
+		}
+
+		for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+			if (strcmp(ifa->ifa_name, name) == 0) {
+				ifexists = 1;
+				break;
+			}
+		}
+
+		if (ifexists == 0)
+			break;
+
+		free(name);
+	}
+
+	freeifaddrs(ifaddr);
+	return name;
+}
+
 int setup_private_host_hw_addr(char *veth1)
 {
 	struct ifreq ifr;

src/lxc/network.h

@@ -131,6 +131,11 @@ extern int lxc_neigh_proxy_on(const char *name, int family);
  */
 extern int lxc_neigh_proxy_off(const char *name, int family);
 
+/*
+ * Generate a new unique network interface name
+ */
+extern char *lxc_mkifname(char *template);
+
 extern const char *lxc_net_type_to_str(int type);
 extern int setup_private_host_hw_addr(char *veth1);
 #endif