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* openvswitch: Add support for OVS_FLOW_ATTR_PROBE.Jarno Rajahalme2014-11-101-1/+1
| | | | | | | | | | This new flag is useful for suppressing error logging while probing for datapath features using flow commands. For backwards compatibility reasons the commands are executed normally, but error logging is suppressed. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Constify various function argumentsThomas Graf2014-11-101-5/+6
| | | | | | | Help produce better optimized code. Signed-off-by: Thomas Graf <tgraf@noironetworks.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Extend packet attribute for egress tunnel infoWenyu Zhang2014-11-101-14/+48
| | | | | | | | | | | | | | | OVS vswitch has extended IPFIX exporter to export tunnel headers to improve network visibility. To export this information userspace needs to know egress tunnel for given packet. By extending packet attributes datapath can export egress tunnel info for given packet. So that userspace can ask for egress tunnel info in userspace action. This information is used to build IPFIX data for given flow. Signed-off-by: Wenyu Zhang <wenyuz@vmware.com> Acked-by: Romain Lenglet <rlenglet@vmware.com> Acked-by: Ben Pfaff <blp@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Add basic MPLS support to kernelSimon Horman2014-11-061-6/+11
| | | | | | | | | | | | | | | Allow datapath to recognize and extract MPLS labels into flow keys and execute actions which push, pop, and set labels on packets. Based heavily on work by Leo Alterman, Ravi K, Isaku Yamahata and Joe Stringer. Cc: Ravi K <rkerur@gmail.com> Cc: Leo Alterman <lalterman@nicira.com> Cc: Isaku Yamahata <yamahata@valinux.co.jp> Cc: Joe Stringer <joe@wand.net.nz> Signed-off-by: Simon Horman <horms@verge.net.au> Signed-off-by: Jesse Gross <jesse@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Add support for Geneve tunneling.Jesse Gross2014-10-061-1/+19
| | | | | | | | | | | | | | The Openvswitch implementation is completely agnostic to the options that are in use and can handle newly defined options without further work. It does this by simply matching on a byte array of options and allowing userspace to setup flows on this array. Signed-off-by: Jesse Gross <jesse@nicira.com> Singed-off-by: Ansis Atteka <aatteka@nicira.com> Signed-off-by: Andy Zhou <azhou@nicira.com> Acked-by: Thomas Graf <tgraf@noironetworks.com> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Wrap struct ovs_key_ipv4_tunnel in a new structure.Jesse Gross2014-10-061-13/+17
| | | | | | | | | | | | | | | | | Currently, the flow information that is matched for tunnels and the tunnel data passed around with packets is the same. However, as additional information is added this is not necessarily desirable, as in the case of pointers. This adds a new structure for tunnel metadata which currently contains only the existing struct. This change is purely internal to the kernel since the current OVS_KEY_ATTR_IPV4_TUNNEL is simply a compressed version of OVS_KEY_ATTR_TUNNEL that is translated at flow setup. Signed-off-by: Jesse Gross <jesse@nicira.com> Signed-off-by: Andy Zhou <azhou@nicira.com> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Add recirc and hash action.Andy Zhou2014-09-161-0/+3
| | | | | | | | | | | | | | | | | | | | | Recirc action allows a packet to reenter openvswitch processing. currently openvswitch lookup flow for packet received and execute set of actions on that packet, with help of recirc action we can process/modify the packet and recirculate it back in openvswitch for another pass. OVS hash action calculates 5-tupple hash and set hash in flow-key hash. This can be used along with recirculation for distributing packets among different ports for bond devices. For example: OVS bonding can use following actions: Match on: bond flow; Action: hash, recirc(id) Match on: recirc-id == id and hash lower bits == a; Action: output port_bond_a Signed-off-by: Andy Zhou <azhou@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Use tun_key only for egress tunnel path.Pravin B Shelar2014-09-161-1/+2
| | | | | | | | | Currently tun_key is used for passing tunnel information on ingress and egress path, this cause confusion. Following patch removes its use on ingress path make it egress only parameter. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Andy Zhou <azhou@nicira.com>
* openvswitch: refactor ovs flow extract API.Pravin B Shelar2014-09-161-1/+5
| | | | | | | | | OVS flow extract is called on packet receive or packet execute code path. Following patch defines separate API for extracting flow-key in packet execute code path. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Andy Zhou <azhou@nicira.com>
* openvswitch: Fix tracking of flags seen in TCP flows.Ben Pfaff2014-06-291-2/+3
| | | | | | | | | | | | | | | | | Flow statistics need to take into account the TCP flags from the packet currently being processed (in 'key'), not the TCP flags matched by the flow found in the kernel flow table (in 'flow'). This bug made the Open vSwitch userspace fin_timeout action have no effect in many cases. This bug is introduced by commit 88d73f6c411ac2f0578 (openvswitch: Use TCP flags in the flow key for stats.) Reported-by: Len Gao <leng@vmware.com> Signed-off-by: Ben Pfaff <blp@nicira.com> Acked-by: Jarno Rajahalme <jrajahalme@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Fix ovs_flow_stats_get/clear RCU dereference.Jarno Rajahalme2014-05-231-3/+3
| | | | | | | | | | | | | | For ovs_flow_stats_get() using ovsl_dereference() was wrong, since flow dumps call this with RCU read lock. ovs_flow_stats_clear() is always called with ovs_mutex, so can use ovsl_dereference(). Also, make the ovs_flow_stats_get() 'flow' argument const to make later patches cleaner. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Compact sw_flow_key.Jarno Rajahalme2014-05-231-18/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Minimize padding in sw_flow_key and move 'tp' top the main struct. These changes simplify code when accessing the transport port numbers and the tcp flags, and makes the sw_flow_key 8 bytes smaller on 64-bit systems (128->120 bytes). These changes also make the keys for IPv4 packets to fit in one cache line. There is a valid concern for safety of packing the struct ovs_key_ipv4_tunnel, as it would be possible to take the address of the tun_id member as a __be64 * which could result in unaligned access in some systems. However: - sw_flow_key itself is 64-bit aligned, so the tun_id within is always 64-bit aligned. - We never make arrays of ovs_key_ipv4_tunnel (which would force every second tun_key to be misaligned). - We never take the address of the tun_id in to a __be64 *. - Whereever we use struct ovs_key_ipv4_tunnel outside the sw_flow_key, it is in stack (on tunnel input functions), where compiler has full control of the alignment. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* openvswitch: Per NUMA node flow stats.Jarno Rajahalme2014-05-161-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Keep kernel flow stats for each NUMA node rather than each (logical) CPU. This avoids using the per-CPU allocator and removes most of the kernel-side OVS locking overhead otherwise on the top of perf reports and allows OVS to scale better with higher number of threads. With 9 handlers and 4 revalidators netperf TCP_CRR test flow setup rate doubles on a server with two hyper-threaded physical CPUs (16 logical cores each) compared to the current OVS master. Tested with non-trivial flow table with a TCP port match rule forcing all new connections with unique port numbers to OVS userspace. The IP addresses are still wildcarded, so the kernel flows are not considered as exact match 5-tuple flows. This type of flows can be expected to appear in large numbers as the result of more effective wildcarding made possible by improvements in OVS userspace flow classifier. Perf results for this test (master): Events: 305K cycles + 8.43% ovs-vswitchd [kernel.kallsyms] [k] mutex_spin_on_owner + 5.64% ovs-vswitchd [kernel.kallsyms] [k] __ticket_spin_lock + 4.75% ovs-vswitchd ovs-vswitchd [.] find_match_wc + 3.32% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_lock + 2.61% ovs-vswitchd [kernel.kallsyms] [k] pcpu_alloc_area + 2.19% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask_range + 2.03% swapper [kernel.kallsyms] [k] intel_idle + 1.84% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_unlock + 1.64% ovs-vswitchd ovs-vswitchd [.] classifier_lookup + 1.58% ovs-vswitchd libc-2.15.so [.] 0x7f4e6 + 1.07% ovs-vswitchd [kernel.kallsyms] [k] memset + 1.03% netperf [kernel.kallsyms] [k] __ticket_spin_lock + 0.92% swapper [kernel.kallsyms] [k] __ticket_spin_lock ... And after this patch: Events: 356K cycles + 6.85% ovs-vswitchd ovs-vswitchd [.] find_match_wc + 4.63% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_lock + 3.06% ovs-vswitchd [kernel.kallsyms] [k] __ticket_spin_lock + 2.81% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask_range + 2.51% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_unlock + 2.27% ovs-vswitchd ovs-vswitchd [.] classifier_lookup + 1.84% ovs-vswitchd libc-2.15.so [.] 0x15d30f + 1.74% ovs-vswitchd [kernel.kallsyms] [k] mutex_spin_on_owner + 1.47% swapper [kernel.kallsyms] [k] intel_idle + 1.34% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask + 1.33% ovs-vswitchd ovs-vswitchd [.] rule_actions_unref + 1.16% ovs-vswitchd ovs-vswitchd [.] hindex_node_with_hash + 1.16% ovs-vswitchd ovs-vswitchd [.] do_xlate_actions + 1.09% ovs-vswitchd ovs-vswitchd [.] ofproto_rule_ref + 1.01% netperf [kernel.kallsyms] [k] __ticket_spin_lock ... There is a small increase in kernel spinlock overhead due to the same spinlock being shared between multiple cores of the same physical CPU, but that is barely visible in the netperf TCP_CRR test performance (maybe ~1% performance drop, hard to tell exactly due to variance in the test results), when testing for kernel module throughput (with no userspace activity, handful of kernel flows). On flow setup, a single stats instance is allocated (for the NUMA node 0). As CPUs from multiple NUMA nodes start updating stats, new NUMA-node specific stats instances are allocated. This allocation on the packet processing code path is made to never block or look for emergency memory pools, minimizing the allocation latency. If the allocation fails, the existing preallocated stats instance is used. Also, if only CPUs from one NUMA-node are updating the preallocated stats instance, no additional stats instances are allocated. This eliminates the need to pre-allocate stats instances that will not be used, also relieving the stats reader from the burden of reading stats that are never used. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Remove 5-tuple optimization.Jarno Rajahalme2014-05-161-9/+1
| | | | | | | | | The 5-tuple optimization becomes unnecessary with a later per-NUMA node stats patch. Remove it first to make the changes easier to grasp. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Per cpu flow stats.Pravin B Shelar2014-01-071-7/+22
| | | | | | | | | | | | With mega flow implementation ovs flow can be shared between multiple CPUs which makes stats updates highly contended operation. This patch uses per-CPU stats in cases where a flow is likely to be shared (if there is a wildcard in the 5-tuple and therefore likely to be spread by RSS). In other situations, it uses the current strategy, saving memory and allocation time. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Shrink sw_flow_mask by 8 bytes (64-bit) or 4 bytes (32-bit).Ben Pfaff2014-01-071-2/+2
| | | | | | | | | | | | | | | We won't normally have a ton of flow masks but using a size_t to store values no bigger than sizeof(struct sw_flow_key) seems excessive. This reduces sw_flow_key_range and sw_flow_mask by 4 bytes on 32-bit systems. On 64-bit systems it shrinks sw_flow_key_range by 12 bytes but sw_flow_mask only by 8 bytes due to padding. Compile tested only. Signed-off-by: Ben Pfaff <blp@nicira.com> Acked-by: Andy Zhou <azhou@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: TCP flags matching support.Jarno Rajahalme2013-11-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tcp_flags=flags/mask Bitwise match on TCP flags. The flags and mask are 16-bit num‐ bers written in decimal or in hexadecimal prefixed by 0x. Each 1-bit in mask requires that the corresponding bit in port must match. Each 0-bit in mask causes the corresponding bit to be ignored. TCP protocol currently defines 9 flag bits, and additional 3 bits are reserved (must be transmitted as zero), see RFCs 793, 3168, and 3540. The flag bits are, numbering from the least significant bit: 0: FIN No more data from sender. 1: SYN Synchronize sequence numbers. 2: RST Reset the connection. 3: PSH Push function. 4: ACK Acknowledgement field significant. 5: URG Urgent pointer field significant. 6: ECE ECN Echo. 7: CWR Congestion Windows Reduced. 8: NS Nonce Sum. 9-11: Reserved. 12-15: Not matchable, must be zero. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Widen TCP flags handling.Jarno Rajahalme2013-11-021-1/+1
| | | | | | | | | | Widen TCP flags handling from 7 bits (uint8_t) to 12 bits (uint16_t). The kernel interface remains at 8 bits, which makes no functional difference now, as none of the higher bits is currently of interest to the userspace. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Restructure datapath.c and flow.cPravin B Shelar2013-10-041-102/+26
| | | | | | | | | | | | | | | Over the time datapath.c and flow.c has became pretty large files. Following patch restructures functionality of component into three different components: flow.c: contains flow extract. flow_netlink.c: netlink flow api. flow_table.c: flow table api. This patch restructures code without changing logic. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Fix alignment of struct sw_flow_key.Jesse Gross2013-09-051-1/+1
| | | | | | | | | | | | | | sw_flow_key alignment was declared as " __aligned(__alignof__(long))". However, this breaks on the m68k architecture where long is 32 bit in size but 16 bit aligned by default. This aligns to the size of a long to ensure that we can always do comparsions in full long-sized chunks. It also adds an additional build check to catch any reduction in alignment. CC: Andy Zhou <azhou@nicira.com> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: optimize flow compare and mask functionsAndy Zhou2013-08-271-18/+1
| | | | | | | | | | | | | | | | Make sure the sw_flow_key structure and valid mask boundaries are always machine word aligned. Optimize the flow compare and mask operations using machine word size operations. This patch improves throughput on average by 15% when CPU is the bottleneck of forwarding packets. This patch is inspired by ideas and code from a patch submitted by Peter Klausler titled "replace memcmp() with specialized comparator". However, The original patch only optimizes for architectures support unaligned machine word access. This patch optimizes for all architectures. Signed-off-by: Andy Zhou <azhou@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Rename key_len to key_endAndy Zhou2013-08-261-1/+1
| | | | | | | | Key_end is a better name describing the ending boundary than key_len. Rename those variables to make it less confusing. Signed-off-by: Andy Zhou <azhou@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Add SCTP supportJoe Stringer2013-08-261-4/+4
| | | | | | | | | | | | | | | This patch adds support for rewriting SCTP src,dst ports similar to the functionality already available for TCP/UDP. Rewriting SCTP ports is expensive due to double-recalculation of the SCTP checksums; this is performed to ensure that packets traversing OVS with invalid checksums will continue to the destination with any checksum corruption intact. Reviewed-by: Simon Horman <horms@verge.net.au> Signed-off-by: Joe Stringer <joe@wand.net.nz> Signed-off-by: Ben Pfaff <blp@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Mega flow implementationAndy Zhou2013-08-241-19/+77
| | | | | | | | | | | | | | | | | | Add wildcarded flow support in kernel datapath. Wildcarded flow can improve OVS flow set up performance by avoid sending matching new flows to the user space program. The exact performance boost will largely dependent on wildcarded flow hit rate. In case all new flows hits wildcard flows, the flow set up rate is within 5% of that of linux bridge module. Pravin has made significant contributions to this patch. Including API clean ups and bug fixes. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Andy Zhou <azhou@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Add gre tunnel support.Pravin B Shelar2013-06-201-1/+17
| | | | | | | | | | Add gre vport implementation. Most of gre protocol processing is pushed to gre module. It make use of gre demultiplexer therefore it can co-exist with linux device based gre tunnels. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Optimize flow key match for non tunnel flows.Pravin B Shelar2013-06-201-3/+3
| | | | | | | | | Following patch adds start offset for sw_flow-key, so that we can skip tunneling information in key for non-tunnel flows. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Expand action buffer size.Pravin B Shelar2013-06-201-1/+1
| | | | | | | | | MAX_ACTIONS_BUFSIZE limits action list size, set tunnel action needs extra space on action list, for now increase max actions list limit. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Add tunneling interface.Pravin B Shelar2013-06-201-0/+19
| | | | | | | | Add ovs tunnel interface for set tunnel action for userspace. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Copy individual actions.Pravin B Shelar2013-06-201-1/+1
| | | | | | | | | | | | | Rather than validating actions and then copying all actiaons in one block, following patch does same operation in single pass. This validate and copy action one by one. This is required for ovs tunneling patch. This patch does not change any functionality. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* openvswitch: Simplify interface ovs_flow_metadata_from_nlattrs()Pravin B Shelar2013-06-151-2/+2
| | | | | | | This is not functional change, this is just code cleanup. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Refine Netlink message size calculation and kill FLOW_BUFSIZEThomas Graf2013-03-301-21/+0
| | | | | | | | | | | Kills the FLOW_BUFSIZE constant which needs to be calculated manually and replaces it with key_attr_size() based on nla_total_size(). Calculates the size of datapath messages instead of relying on NLMSG_DEFAULT_SIZE and moves the existing message size calculations into own functions for clarity. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: add skb mark matching and set actionAnsis Atteka2012-11-261-3/+5
| | | | | | | This patch adds support for skb mark matching and set action. Signed-off-by: Ansis Atteka <aatteka@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2012-09-151-3/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: net/netfilter/nfnetlink_log.c net/netfilter/xt_LOG.c Rather easy conflict resolution, the 'net' tree had bug fixes to make sure we checked if a socket is a time-wait one or not and elide the logging code if so. Whereas on the 'net-next' side we are calculating the UID and GID from the creds using different interfaces due to the user namespace changes from Eric Biederman. Signed-off-by: David S. Miller <davem@davemloft.net>
| * openvswitch: Fix FLOW_BUFSIZE definition.Jesse Gross2012-09-041-3/+5
| | | | | | | | | | | | | | | | | | | | | | The vlan encapsulation fields in the maximum flow defintion were never updated when the representation changed before upstreaming. In theory this could cause a kernel panic when a maximum length flow is used. In practice this has never happened (to my knowledge) because skb allocations are padded out to a cache line so you would need the right combination of flow and packet being sent to userspace. Signed-off-by: Jesse Gross <jesse@nicira.com>
* | openvswitch: Increase maximum number of datapath ports.Pravin B Shelar2012-09-041-1/+2
|/ | | | | | | Use hash table to store ports of datapath. Allow 64K ports per switch. Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* openvswitch: Replace Nicira Networks.Raju Subramanian2012-05-041-1/+1
| | | | | | | | Replaced all instances of Nicira Networks(, Inc) to Nicira, Inc. Signed-off-by: Raju Subramanian <rsubramanian@nicira.com> Signed-off-by: Ben Pfaff <blp@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
* net: Add Open vSwitch kernel components.Jesse Gross2011-12-031-0/+199
Open vSwitch is a multilayer Ethernet switch targeted at virtualized environments. In addition to supporting a variety of features expected in a traditional hardware switch, it enables fine-grained programmatic extension and flow-based control of the network. This control is useful in a wide variety of applications but is particularly important in multi-server virtualization deployments, which are often characterized by highly dynamic endpoints and the need to maintain logical abstractions for multiple tenants. The Open vSwitch datapath provides an in-kernel fast path for packet forwarding. It is complemented by a userspace daemon, ovs-vswitchd, which is able to accept configuration from a variety of sources and translate it into packet processing rules. See http://openvswitch.org for more information and userspace utilities. Signed-off-by: Jesse Gross <jesse@nicira.com>