From 8aed4223e0933c0602c1e624b07094d7f7afb23d Mon Sep 17 00:00:00 2001 From: Justin Pettit Date: Tue, 13 Apr 2010 21:24:37 -0700 Subject: [PATCH] netdev: Add support for "patch" type This commit introduces a new netdev type called "patch". A patch is a pair of interfaces, in which frames sent through one of the devices pop out of the other. This is useful for linking together datapaths. A patch's only argument on creation is "peer", which specifies the other side of the patch. A patch must be created in pairs, so a second netdev must be created with the "name" and "peer" values reversed. The current implementation is built using veth devices. Further, it's limited to the veth devices which support configuration through sysfs. This limits the ability to use a "patch" on 2.6.18 kernels using the veth device we include (read: flavors of XenServer 5.5). In the not too distant future, the implementation will be modified to use the new kernel port abstraction introduced by Jesse Gross's forthcoming GRE work. At that point, patch devices will work on any Linux platform supported by OVS. --- lib/netdev-linux.c | 195 +++++++++++++++++++++++++++++++++++++++++- lib/netdev-provider.h | 1 + lib/netdev.c | 1 + vswitchd/vswitch.xml | 6 ++ 4 files changed, 201 insertions(+), 2 deletions(-) diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c index 736b588a..2941bf98 100644 --- a/lib/netdev-linux.c +++ b/lib/netdev-linux.c @@ -91,6 +91,10 @@ struct tap_state { int fd; }; +struct patch_state { + char *peer; +}; + struct netdev_dev_linux { struct netdev_dev netdev_dev; @@ -107,6 +111,7 @@ struct netdev_dev_linux { union { struct tap_state tap; + struct patch_state patch; } state; }; @@ -152,6 +157,7 @@ static struct rtnetlink_notifier netdev_linux_poll_notifier; * additional log messages. */ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20); +static int if_up(const char *name); static int destroy_gre(const char *name); static int netdev_linux_do_ethtool(const char *name, struct ethtool_cmd *, int cmd, const char *cmd_name); @@ -177,7 +183,7 @@ netdev_dev_linux_cast(const struct netdev_dev *netdev_dev) { const char *type = netdev_dev_get_type(netdev_dev); assert(!strcmp(type, "system") || !strcmp(type, "tap") - || !strcmp(type, "gre")); + || !strcmp(type, "gre") || !strcmp(type, "patch")); return CONTAINER_OF(netdev_dev, struct netdev_dev_linux, netdev_dev); } @@ -186,7 +192,7 @@ netdev_linux_cast(const struct netdev *netdev) { const char *type = netdev_get_type(netdev); assert(!strcmp(type, "system") || !strcmp(type, "tap") - || !strcmp(type, "gre")); + || !strcmp(type, "gre") || !strcmp(type, "patch")); return CONTAINER_OF(netdev, struct netdev_linux, netdev); } @@ -581,6 +587,106 @@ error: return error; } +/* A veth may be created using the 'command' "+,". A veth may + * be destroyed by using the 'command' "-", where can be + * either side of the device. + */ +static int +modify_veth(const char *format, ...) +{ + FILE *veth_file; + va_list args; + int retval; + + veth_file = fopen("/sys/class/net/veth_pairs", "w"); + if (!veth_file) { + VLOG_WARN_RL(&rl, "could not open veth device. Are you running a " + "supported XenServer with the kernel module loaded?"); + return ENODEV; + } + setvbuf(veth_file, NULL, _IONBF, 0); + + va_start(args, format); + retval = vfprintf(veth_file, format, args); + va_end(args); + + fclose(veth_file); + if (retval < 0) { + VLOG_WARN_RL(&rl, "could not destroy patch: %s", strerror(errno)); + return errno; + } + + return 0; +} + +static int +create_patch(const char *name, const char *peer) +{ + int retval; + struct netdev_dev *peer_nd; + + + /* Only create the veth if the peer didn't already do it. */ + peer_nd = netdev_dev_from_name(peer); + if (peer_nd) { + if (!strcmp("patch", netdev_dev_get_type(peer_nd))) { + struct netdev_dev_linux *ndl = netdev_dev_linux_cast(peer_nd); + if (!strcmp(name, ndl->state.patch.peer)) { + return 0; + } else { + VLOG_WARN_RL(&rl, "peer '%s' already paired with '%s'", + peer, ndl->state.patch.peer); + return EINVAL; + } + } else { + VLOG_WARN_RL(&rl, "peer '%s' exists and is not a patch", peer); + return EINVAL; + } + } + + retval = modify_veth("+%s,%s", name, peer); + if (retval) { + return retval; + } + + retval = if_up(name); + if (retval) { + return retval; + } + + retval = if_up(peer); + if (retval) { + return retval; + } + + return 0; +} + +static int +setup_patch(const char *name, const struct shash *args, char **peer_) +{ + const char *peer; + + peer = shash_find_data(args, "peer"); + if (!peer) { + VLOG_WARN("patch type requires valid 'peer' argument"); + return EINVAL; + } + + if (shash_count(args) > 1) { + VLOG_WARN("patch type takes only a 'peer' argument"); + return EINVAL; + } + + if (strlen(peer) >= IFNAMSIZ) { + VLOG_WARN_RL(&rl, "patch 'peer' arg too long"); + return EINVAL; + } + + *peer_ = xstrdup(peer); + return create_patch(name, peer); +} + /* Creates the netdev device of 'type' with 'name'. */ static int netdev_linux_create_system(const char *name, const char *type OVS_UNUSED, @@ -710,6 +816,28 @@ error: return error; } +static int +netdev_linux_create_patch(const char *name, const char *type OVS_UNUSED, + const struct shash *args, struct netdev_dev **netdev_devp) +{ + struct netdev_dev_linux *netdev_dev; + char *peer = NULL; + int error; + + error = setup_patch(name, args, &peer); + if (error) { + free(peer); + return error; + } + + netdev_dev = xzalloc(sizeof *netdev_dev); + netdev_dev->state.patch.peer = peer; + netdev_dev_init(&netdev_dev->netdev_dev, name, &netdev_patch_class); + *netdev_devp = &netdev_dev->netdev_dev; + + return 0; +} + static int netdev_linux_reconfigure_gre(struct netdev_dev *netdev_dev_, const struct shash *args) @@ -799,6 +927,19 @@ destroy_gre(const char *name) } } +static void +destroy_patch(struct netdev_dev_linux *netdev_dev) +{ + const char *name = netdev_dev_get_name(&netdev_dev->netdev_dev); + struct patch_state *state = &netdev_dev->state.patch; + + /* Only destroy veth if 'peer' doesn't exist as an existing netdev. */ + if (!netdev_dev_from_name(state->peer)) { + modify_veth("-%s", name); + } + free(state->peer); +} + /* Destroys the netdev device 'netdev_dev_'. */ static void netdev_linux_destroy(struct netdev_dev *netdev_dev_) @@ -816,6 +957,8 @@ netdev_linux_destroy(struct netdev_dev *netdev_dev_) destroy_tap(netdev_dev); } else if (!strcmp(type, "gre")) { destroy_gre(netdev_dev_get_name(&netdev_dev->netdev_dev)); + } else if (!strcmp(type, "patch")) { + destroy_patch(netdev_dev); } free(netdev_dev_); @@ -2102,6 +2245,54 @@ const struct netdev_class netdev_gre_class = { netdev_linux_poll_add, netdev_linux_poll_remove, }; + +const struct netdev_class netdev_patch_class = { + "patch", + + netdev_linux_init, + netdev_linux_run, + netdev_linux_wait, + + netdev_linux_create_patch, + netdev_linux_destroy, + NULL, /* reconfigure */ + + netdev_linux_open, + netdev_linux_close, + + NULL, /* enumerate */ + + netdev_linux_recv, + netdev_linux_recv_wait, + netdev_linux_drain, + + netdev_linux_send, + netdev_linux_send_wait, + + netdev_linux_set_etheraddr, + netdev_linux_get_etheraddr, + netdev_linux_get_mtu, + netdev_linux_get_ifindex, + netdev_linux_get_carrier, + netdev_linux_get_stats, + + netdev_linux_get_features, + netdev_linux_set_advertisements, + netdev_linux_get_vlan_vid, + netdev_linux_set_policing, + + netdev_linux_get_in4, + netdev_linux_set_in4, + netdev_linux_get_in6, + netdev_linux_add_router, + netdev_linux_get_next_hop, + netdev_linux_arp_lookup, + + netdev_linux_update_flags, + + netdev_linux_poll_add, + netdev_linux_poll_remove, +}; static int get_stats_via_netlink(int ifindex, struct netdev_stats *stats) diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h index e1c18ccb..aac482b0 100644 --- a/lib/netdev-provider.h +++ b/lib/netdev-provider.h @@ -385,6 +385,7 @@ struct netdev_class { extern const struct netdev_class netdev_linux_class; extern const struct netdev_class netdev_tap_class; extern const struct netdev_class netdev_gre_class; +extern const struct netdev_class netdev_patch_class; #ifdef __cplusplus } diff --git a/lib/netdev.c b/lib/netdev.c index 99b5d243..af2382d3 100644 --- a/lib/netdev.c +++ b/lib/netdev.c @@ -45,6 +45,7 @@ static const struct netdev_class *base_netdev_classes[] = { &netdev_linux_class, &netdev_tap_class, &netdev_gre_class, + &netdev_patch_class, }; static struct shash netdev_classes = SHASH_INITIALIZER(&netdev_classes); diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml index d3f3efbb..e1019e2d 100644 --- a/vswitchd/vswitch.xml +++ b/vswitchd/vswitch.xml @@ -357,6 +357,12 @@
A TUN/TAP device managed by Open vSwitch.
gre
A GRE tunnel device managed by Open vSwitch.
+
patch
+
A pair of virtual devices that act as a patch cable. A + peer argument is required that indicates the name + of the other side of the patch. Since a patch must work in + pairs, a second patch interface must be declared with the + name and peer arguments reversed.
-- 2.30.2