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netdev: Allow explicit creation of netdev objects

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This change adds netdev_create() and netdev_destroy() functions to allow
the creation of network devices through the netdev library.  Previously,
network devices had to already exist or be created on demand through
netdev_open().  This caused problems such as not being able to specify
TAP devices as ports in ovs-vswitchd, which this patch fixes.

This also lays the groundwork for adding GRE and VDE support.
This commit is contained in:
Justin Pettit
2009-12-01 01:14:33 -08:00
parent f20279afbd
commit 6c88d577e8
6 changed files with 422 additions and 55 deletions
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115
lib/netdev-linux.c
View File

@@ -67,6 +67,14 @@
#define ADVERTISED_Asym_Pause (1 << 14)
#endif
/* Provider-specific netdev object. Netdev objects are devices that are
* created by the netdev library through a netdev_create() call. */
struct netdev_obj_linux {
struct netdev_obj netdev_obj;
int tap_fd; /* File descriptor for TAP device. */
};
struct netdev_linux {
struct netdev netdev;
@@ -142,6 +150,13 @@ static int set_etheraddr(const char *netdev_name, int hwaddr_family,
static int get_stats_via_netlink(int ifindex, struct netdev_stats *stats);
static int get_stats_via_proc(const char *netdev_name, struct netdev_stats *stats);
static struct netdev_obj_linux *
netdev_obj_linux_cast(const struct netdev_obj *netdev_obj)
{
netdev_obj_assert_class(netdev_obj, &netdev_linux_class);
return CONTAINER_OF(netdev_obj, struct netdev_obj_linux, netdev_obj);
}
static struct netdev_linux *
netdev_linux_cast(const struct netdev *netdev)
{
@@ -194,9 +209,77 @@ netdev_linux_cache_cb(const struct rtnetlink_change *change,
}
}
/* Creates the netdev object of 'type' with 'name'. */
static int
netdev_linux_open(const char *name, char *suffix, int ethertype,
struct netdev **netdevp)
netdev_linux_create(const char *name, const char *type,
const struct shash *args, bool created)
{
struct netdev_obj_linux *netdev_obj;
static const char tap_dev[] = "/dev/net/tun";
struct ifreq ifr;
int error;
if (!shash_is_empty(args)) {
VLOG_WARN("arguments for %s devices should be empty", type);
}
/* Create the name binding in the netdev library for this object. */
netdev_obj = xcalloc(1, sizeof *netdev_obj);
netdev_obj_init(&netdev_obj->netdev_obj, name, &netdev_linux_class,
created);
netdev_obj->tap_fd = -1;
if (strcmp(type, "tap")) {
return 0;
}
/* Open tap device. */
netdev_obj->tap_fd = open(tap_dev, O_RDWR);
if (netdev_obj->tap_fd < 0) {
error = errno;
VLOG_WARN("opening \"%s\" failed: %s", tap_dev, strerror(error));
goto error;
}
/* Create tap device. */
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
if (ioctl(netdev_obj->tap_fd, TUNSETIFF, &ifr) == -1) {
VLOG_WARN("%s: creating tap device failed: %s", name,
strerror(errno));
error = errno;
goto error;
}
/* Make non-blocking. */
error = set_nonblocking(netdev_obj->tap_fd);
if (error) {
goto error;
}
return 0;
error:
netdev_destroy(name);
return error;
}
/* Destroys the netdev object 'netdev_obj_'. */
static void
netdev_linux_destroy(struct netdev_obj *netdev_obj_)
{
struct netdev_obj_linux *netdev_obj = netdev_obj_linux_cast(netdev_obj_);
if (netdev_obj->tap_fd >= 0) {
close(netdev_obj->tap_fd);
}
free(netdev_obj);
return;
}
static int
netdev_linux_open(const char *name, int ethertype, struct netdev **netdevp)
{
struct netdev_linux *netdev;
enum netdev_flags flags;
@@ -204,10 +287,10 @@ netdev_linux_open(const char *name, char *suffix, int ethertype,
/* Allocate network device. */
netdev = xcalloc(1, sizeof *netdev);
netdev_init(&netdev->netdev, suffix, &netdev_linux_class);
netdev_init(&netdev->netdev, name, &netdev_linux_class);
netdev->netdev_fd = -1;
netdev->tap_fd = -1;
netdev->cache = shash_find_data(&cache_map, suffix);
netdev->cache = shash_find_data(&cache_map, name);
if (!netdev->cache) {
if (shash_is_empty(&cache_map)) {
int error = rtnetlink_notifier_register(
@@ -218,14 +301,14 @@ netdev_linux_open(const char *name, char *suffix, int ethertype,
}
}
netdev->cache = xmalloc(sizeof *netdev->cache);
netdev->cache->shash_node = shash_add(&cache_map, suffix,
netdev->cache->shash_node = shash_add(&cache_map, name,
netdev->cache);
netdev->cache->valid = 0;
netdev->cache->ref_cnt = 0;
}
netdev->cache->ref_cnt++;
if (!strncmp(name, "tap:", 4)) {
if (!strcmp(netdev_get_type(&netdev->netdev), "tap")) {
static const char tap_dev[] = "/dev/net/tun";
struct ifreq ifr;
@@ -239,9 +322,9 @@ netdev_linux_open(const char *name, char *suffix, int ethertype,
/* Create tap device. */
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strncpy(ifr.ifr_name, suffix, sizeof ifr.ifr_name);
strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
if (ioctl(netdev->tap_fd, TUNSETIFF, &ifr) == -1) {
VLOG_WARN("%s: creating tap device failed: %s", suffix,
VLOG_WARN("%s: creating tap device failed: %s", name,
strerror(errno));
error = errno;
goto error;
@@ -296,7 +379,7 @@ netdev_linux_open(const char *name, char *suffix, int ethertype,
if (bind(netdev->netdev_fd,
(struct sockaddr *) &sll, sizeof sll) < 0) {
error = errno;
VLOG_ERR("bind to %s failed: %s", suffix, strerror(error));
VLOG_ERR("bind to %s failed: %s", name, strerror(error));
goto error;
}
@@ -1377,13 +1460,16 @@ netdev_linux_poll_remove(struct netdev_notifier *notifier_)
}
const struct netdev_class netdev_linux_class = {
"", /* prefix */
"linux", /* name */
"system", /* type */
netdev_linux_init,
netdev_linux_run,
netdev_linux_wait,
netdev_linux_create,
netdev_linux_destroy,
NULL, /* reconfigure */
netdev_linux_open,
netdev_linux_close,
@@ -1422,13 +1508,16 @@ const struct netdev_class netdev_linux_class = {
};
const struct netdev_class netdev_tap_class = {
"tap", /* prefix */
"tap", /* name */
"tap", /* type */
netdev_linux_init,
NULL, /* run */
NULL, /* wait */
netdev_linux_create,
netdev_linux_destroy,
NULL, /* reconfigure */
netdev_linux_open,
netdev_linux_close,