summaryrefslogtreecommitdiffstats
path: root/Documentation/networking/vxlan.rst
diff options
context:
space:
mode:
authorSven Schnelle <svens@linux.ibm.com>2026-09-09 11:29:53 +0200
committerMasami Hiramatsu (Google) <mhiramat@kernel.org>2026-09-10 08:43:35 +0900
commitd22c3e0088e85be8131f7a9283f759cdbb20726d (patch)
tree9668df2aa27b26f850d3ba5ba1287e443803675c /Documentation/networking/vxlan.rst
downloadlinux-stable-d22c3e0088e85be8131f7a9283f759cdbb20726d.tar.gz
linux-stable-d22c3e0088e85be8131f7a9283f759cdbb20726d.zip
selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tcgrafted
The current regex also matches symbols in modules, which makes the test fail on s390 where name_show is present only once in the kernel, but also multiple times in modules: 000001b1401cdc20 t name_show 000001b0c05e6c40 t name_show [mdev] 000001b0c0495f30 t name_show [i2c_core] Fix this by changing the regular expression to only match the function name. Link: https://lore.kernel.org/all/20260909092954.2200558-1-svens@linux.ibm.com/ Fixes: 03b80ff8023a ("selftests/ftrace: Add new test case which checks non unique symbol") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'Documentation/networking/vxlan.rst')
-rw-r--r--Documentation/networking/vxlan.rst88
1 files changed, 88 insertions, 0 deletions
diff --git a/Documentation/networking/vxlan.rst b/Documentation/networking/vxlan.rst
new file mode 100644
index 000000000..2759dc1cc
--- /dev/null
+++ b/Documentation/networking/vxlan.rst
@@ -0,0 +1,88 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================================
+Virtual eXtensible Local Area Networking documentation
+======================================================
+
+The VXLAN protocol is a tunnelling protocol designed to solve the
+problem of limited VLAN IDs (4096) in IEEE 802.1q. With VXLAN the
+size of the identifier is expanded to 24 bits (16777216).
+
+VXLAN is described by IETF RFC 7348, and has been implemented by a
+number of vendors. The protocol runs over UDP using a single
+destination port. This document describes the Linux kernel tunnel
+device, there is also a separate implementation of VXLAN for
+Openvswitch.
+
+Unlike most tunnels, a VXLAN is a 1 to N network, not just point to
+point. A VXLAN device can learn the IP address of the other endpoint
+either dynamically in a manner similar to a learning bridge, or make
+use of statically-configured forwarding entries.
+
+The management of vxlan is done in a manner similar to its two closest
+neighbors GRE and VLAN. Configuring VXLAN requires the version of
+iproute2 that matches the kernel release where VXLAN was first merged
+upstream.
+
+1. Create vxlan device::
+
+ # ip link add vxlan0 type vxlan id 42 group 239.1.1.1 dev eth1 dstport 4789
+
+This creates a new device named vxlan0. The device uses the multicast
+group 239.1.1.1 over eth1 to handle traffic for which there is no
+entry in the forwarding table. The destination port number is set to
+the IANA-assigned value of 4789. The Linux implementation of VXLAN
+pre-dates the IANA's selection of a standard destination port number
+and uses the Linux-selected value by default to maintain backwards
+compatibility.
+
+2. Delete vxlan device::
+
+ # ip link delete vxlan0
+
+3. Show vxlan info::
+
+ # ip -d link show vxlan0
+
+It is possible to create, destroy and display the vxlan
+forwarding table using the new bridge command.
+
+1. Create forwarding table entry::
+
+ # bridge fdb add to 00:17:42:8a:b4:05 dst 192.19.0.2 dev vxlan0
+
+2. Delete forwarding table entry::
+
+ # bridge fdb delete 00:17:42:8a:b4:05 dev vxlan0
+
+3. Show forwarding table::
+
+ # bridge fdb show dev vxlan0
+
+The following NIC features may indicate support for UDP tunnel-related
+offloads (most commonly VXLAN features, but support for a particular
+encapsulation protocol is NIC specific):
+
+ - `tx-udp_tnl-segmentation`
+ - `tx-udp_tnl-csum-segmentation`
+ ability to perform TCP segmentation offload of UDP encapsulated frames
+
+ - `rx-udp_tunnel-port-offload`
+ receive side parsing of UDP encapsulated frames which allows NICs to
+ perform protocol-aware offloads, like checksum validation offload of
+ inner frames (only needed by NICs without protocol-agnostic offloads)
+
+For devices supporting `rx-udp_tunnel-port-offload` the list of currently
+offloaded ports can be interrogated with `ethtool`::
+
+ $ ethtool --show-tunnels eth0
+ Tunnel information for eth0:
+ UDP port table 0:
+ Size: 4
+ Types: vxlan
+ No entries
+ UDP port table 1:
+ Size: 4
+ Types: geneve, vxlan-gpe
+ Entries (1):
+ port 1230, vxlan-gpe