Merge pull request torvalds#118 from libos-nuse/upstream-refactor-tap

lkl tools: refactor tap code from hijack library to general library

Documentation/lkl.txt

@@ -148,11 +148,19 @@ You can usually use this library via a wrapper script.
 There are environmental variables to configure the behavior of LKL. The followings
 are the list of those variable for your environment.
 
-* LKL_HIJACK_NET_TAP
+* LKL_HIJACK_NET_IFTYPE
 
-  an interface name for tap device in host operating system to connect to LKL.
+  The interface type in host operating system to connect to LKL.
+  The following example specifies a tap interface.
 ```
-    $ LKL_HIJACK_NET_TAP=tap0 lkl-hijack.sh ip address show
+    $ LKL_HIJACK_NET_IFTYPE=tap LKL_HIJACK_NET_IFPARAMS=tap0 lkl-hijack.sh ip address show
+```
+* LKL_HIJACK_NET_IFPARAMS
+
+  Additional configuration parameters for the interface specified by LKL_HIJACK_NET_IFTYPE.
+  The parameters depend on the interface type (LKL_HIJACK_NET_IFTYPE).
+```
+    $ LKL_HIJACK_NET_IFTYPE=tap LKL_HIJACK_NET_IFPARAMS=tap0 lkl-hijack.sh ip address show
 ```
 * LKL_HIJACK_NET_IP
 

tools/lkl/include/lkl.h

@@ -210,13 +210,12 @@ int lkl_set_ipv4_gateway(unsigned int addr);
 
 /**
  * lkl_netdev - host network device handle
- *
- * @fd - TAP device or packet socket file descriptor
  */
-union lkl_netdev {
-	int fd;
+struct lkl_netdev {
+	struct lkl_dev_net_ops *ops;
 };
 
+
 /**
  * lkl_netdev_add - add a new network device
  *
@@ -227,7 +226,7 @@ union lkl_netdev {
  * @returns a network device id (0 is valid) or a strictly negative value in
  * case of error
  */
-int lkl_netdev_add(union lkl_netdev nd, void *mac);
+int lkl_netdev_add(struct lkl_netdev *nd, void *mac);
 
 /**
  * lkl_netdev_get_ifindex - retrieve the interface index for a given network
@@ -256,6 +255,15 @@ int lkl_create_syscall_thread(void);
  */
 int lkl_stop_syscall_thread(void);
 
+/**
+ * lkl_netdev_tap_create - create TAP net_device for the virtio net backend
+ *
+ * @ifname - interface name for the TAP device. need to be configured
+ * on host in advance
+ */
+struct lkl_netdev *lkl_netdev_tap_create(const char *ifname);
+
+
 #ifdef __cplusplus
 }
 #endif

tools/lkl/include/lkl_host.h

@@ -47,14 +47,12 @@ struct lkl_dev_blk_ops {
 	int (*request)(union lkl_disk disk, struct lkl_blk_req *req);
 };
 
-extern struct lkl_dev_net_ops lkl_dev_net_ops;
-
 struct lkl_dev_net_ops {
-	int (*tx)(union lkl_netdev nd, void *data, int len);
-	int (*rx)(union lkl_netdev nd, void *data, int *len);
+	int (*tx)(struct lkl_netdev *nd, void *data, int len);
+	int (*rx)(struct lkl_netdev *nd, void *data, int *len);
 #define LKL_DEV_NET_POLL_RX		1
 #define LKL_DEV_NET_POLL_TX		2
-	int (*poll)(union lkl_netdev nd, int events);
+	int (*poll)(struct lkl_netdev *nd, int events);
 };
 
 #ifdef __cplusplus

tools/lkl/lib/Build

@@ -9,3 +9,4 @@ lkl-y += utils.o
 lkl-y += virtio_blk.o
 lkl-y += virtio.o
 lkl-$(CONFIG_AUTO_LKL_POSIX_HOST) += virtio_net.o
+lkl-$(CONFIG_AUTO_LKL_POSIX_HOST) += virtio_net_tap.o

tools/lkl/lib/hijack/init.c

@@ -139,65 +139,53 @@ static void mount_cmds_exec(char *_cmds, int (*callback)(char*))
 	free(cmds);
 }
 
-int init_tap(char *tap, char *mac_str)
-{
-	struct ifreq ifr = {
-		.ifr_flags = IFF_TAP | IFF_NO_PI,
-	};
-	union lkl_netdev nd;
-	__lkl__u8 mac[LKL_ETH_ALEN] = {0};
-	int ret = -1;
-
-	strncpy(ifr.ifr_name, tap, IFNAMSIZ);
-
-	nd.fd = open("/dev/net/tun", O_RDWR|O_NONBLOCK);
-	if (nd.fd < 0) {
-		fprintf(stderr, "failed to open tap: %s\n", strerror(errno));
-		return -1;
-	}
-
-	ret = ioctl(nd.fd, TUNSETIFF, &ifr);
-	if (ret < 0) {
-		fprintf(stderr, "failed to attach to %s: %s\n",
-			ifr.ifr_name, strerror(errno));
-		return -1;
-	}
-
-	ret = parse_mac_str(mac_str, mac);
-
-	if (ret < 0) {
-		fprintf(stderr, "failed to parse mac\n");
-		return -1;
-	} else if (ret > 0) {
-		ret = lkl_netdev_add(nd, mac);
-	} else {
-		ret = lkl_netdev_add(nd, NULL);
-	}
-
-	if (ret < 0) {
-		fprintf(stderr, "failed to add netdev: %s\n",
-			lkl_strerror(ret));
-		return -1;
-	}
-
-	return ret;
-}
-
 void __attribute__((constructor(102)))
 hijack_init(void)
 {
 	int ret, i, dev_null, nd_id = -1, nd_ifindex = -1;
+	/* OBSOLETE: should use IFTYPE and IFPARAMS */
 	char *tap = getenv("LKL_HIJACK_NET_TAP");
+	char *iftype = getenv("LKL_HIJACK_NET_IFTYPE");
+	char *ifparams = getenv("LKL_HIJACK_NET_IFPARAMS");
 	char *mtu_str = getenv("LKL_HIJACK_NET_MTU");
+	__lkl__u8 mac[LKL_ETH_ALEN] = {0};
 	char *ip = getenv("LKL_HIJACK_NET_IP");
 	char *mac_str = getenv("LKL_HIJACK_NET_MAC");
 	char *netmask_len = getenv("LKL_HIJACK_NET_NETMASK_LEN");
 	char *gateway = getenv("LKL_HIJACK_NET_GATEWAY");
 	char *debug = getenv("LKL_HIJACK_DEBUG");
 	char *mount = getenv("LKL_HIJACK_MOUNT");
+	struct lkl_netdev *nd = NULL;
 
 	if (tap) {
-		nd_id = init_tap(tap, mac_str);
+		fprintf(stderr,
+			"WARN: variable LKL_HIJACK_NET_TAP is now obsoleted.\n"
+			"      please use LKL_HIJACK_NET_IFTYPE and "
+			"LKL_HIJACK_NET_IFPARAMS instead.\n");
+		nd = lkl_netdev_tap_create(tap);
+	}
+
+	if (!nd && iftype && ifparams && (strncmp(iftype, "tap", 3) == 0))
+		nd = lkl_netdev_tap_create(ifparams);
+
+	if (nd) {
+		ret = parse_mac_str(mac_str, mac);
+
+		if (ret < 0) {
+			fprintf(stderr, "failed to parse mac\n");
+			return;
+		} else if (ret > 0) {
+			ret = lkl_netdev_add(nd, mac);
+		} else {
+			ret = lkl_netdev_add(nd, NULL);
+		}
+
+		if (ret < 0) {
+			fprintf(stderr, "failed to add netdev: %s\n",
+				lkl_strerror(ret));
+			return;
+		}
+		nd_id = ret;
 	}
 
 	if (!debug)

tools/lkl/lib/posix-host.c

@@ -5,7 +5,6 @@
 #include <signal.h>
 #include <assert.h>
 #include <unistd.h>
-#include <stdio.h>
 #include <errno.h>
 #include <string.h>
 #include <time.h>
@@ -379,56 +378,3 @@ struct lkl_dev_blk_ops lkl_dev_blk_ops = {
 	.request = blk_request,
 };
 
-static int net_tx(union lkl_netdev nd, void *data, int len)
-{
-	int ret;
-
-	ret = write(nd.fd, data, len);
-	if (ret <= 0 && errno == -EAGAIN)
-		return -1;
-	return 0;
-}
-
-static int net_rx(union lkl_netdev nd, void *data, int *len)
-{
-	int ret;
-
-	ret = read(nd.fd, data, *len);
-	if (ret <= 0)
-		return -1;
-	*len = ret;
-	return 0;
-}
-
-static int net_poll(union lkl_netdev nd, int events)
-{
-	struct pollfd pfd = {
-		.fd = nd.fd,
-	};
-	int ret = 0;
-
-	if (events & LKL_DEV_NET_POLL_RX)
-		pfd.events |= POLLIN | POLLPRI;
-	if (events & LKL_DEV_NET_POLL_TX)
-		pfd.events |= POLLOUT;
-
-	while (poll(&pfd, 1, -1) < 0 && errno == EINTR)
-		;
-
-	if (pfd.revents & (POLLHUP | POLLNVAL))
-		return -1;
-
-	if (pfd.revents & POLLIN)
-		ret |= LKL_DEV_NET_POLL_RX;
-	if (pfd.revents & POLLOUT)
-		ret |= LKL_DEV_NET_POLL_TX;
-
-	return ret;
-}
-
-struct lkl_dev_net_ops lkl_dev_net_ops = {
-	.tx = net_tx,
-	.rx = net_rx,
-	.poll = net_poll,
-};
-

tools/lkl/lib/virtio_net.c

@@ -33,7 +33,7 @@ struct virtio_net_dev {
 	struct virtio_dev dev;
 	struct lkl_virtio_net_config config;
 	struct lkl_dev_net_ops *ops;
-	union lkl_netdev nd;
+	struct lkl_netdev *nd;
 	struct virtio_net_poll rx_poll, tx_poll;
 	struct lkl_mutex_t **queue_locks;
 };
@@ -155,7 +155,7 @@ static struct lkl_mutex_t **init_queue_locks(int num_queues)
 	return ret;
 }
 
-int lkl_netdev_add(union lkl_netdev nd, void *mac)
+int lkl_netdev_add(struct lkl_netdev *nd, void *mac)
 {
 	struct virtio_net_dev *dev;
 	static int count;
@@ -173,7 +173,7 @@ int lkl_netdev_add(union lkl_netdev nd, void *mac)
 	dev->dev.config_data = &dev->config;
 	dev->dev.config_len = sizeof(dev->config);
 	dev->dev.ops = &net_ops;
-	dev->ops = &lkl_dev_net_ops;
+	dev->ops = nd->ops;
 	dev->nd = nd;
 	dev->queue_locks = init_queue_locks(NUM_QUEUES);