diff options
author | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-04-30 19:04:09 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2020-04-30 22:56:36 +0300 |
commit | 63893472d753e97204331e568a5e70290054cb38 (patch) | |
tree | d7b54a73443b58d57f9994c08359d29f38c2253e /Documentation/networking | |
parent | aa3764276a4bc1a927ab8feaad5a255234763d9d (diff) | |
download | linux-63893472d753e97204331e568a5e70290054cb38.tar.xz |
docs: networking: convert openvswitch.txt to ReST
- add SPDX header;
- adjust title markup;
- mark code blocks and literals as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r-- | Documentation/networking/index.rst | 1 | ||||
-rw-r--r-- | Documentation/networking/openvswitch.rst (renamed from Documentation/networking/openvswitch.txt) | 23 |
2 files changed, 14 insertions, 10 deletions
diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index c4e8a43741be..b7f558480aca 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -87,6 +87,7 @@ Contents: netif-msg nf_conntrack-sysctl nf_flowtable + openvswitch .. only:: subproject and html diff --git a/Documentation/networking/openvswitch.txt b/Documentation/networking/openvswitch.rst index b3b9ac61d29d..1a8353dbf1b6 100644 --- a/Documentation/networking/openvswitch.txt +++ b/Documentation/networking/openvswitch.rst @@ -1,3 +1,6 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================= Open vSwitch datapath developer documentation ============================================= @@ -80,13 +83,13 @@ The <linux/openvswitch.h> header file defines the exact format of the flow key attributes. For informal explanatory purposes here, we write them as comma-separated strings, with parentheses indicating arguments and nesting. For example, the following could represent a flow key -corresponding to a TCP packet that arrived on vport 1: +corresponding to a TCP packet that arrived on vport 1:: in_port(1), eth(src=e0:91:f5:21:d0:b2, dst=00:02:e3:0f:80:a4), eth_type(0x0800), ipv4(src=172.16.0.20, dst=172.18.0.52, proto=17, tos=0, frag=no), tcp(src=49163, dst=80) -Often we ellipsize arguments not important to the discussion, e.g.: +Often we ellipsize arguments not important to the discussion, e.g.:: in_port(1), eth(...), eth_type(0x0800), ipv4(...), tcp(...) @@ -151,20 +154,20 @@ Some care is needed to really maintain forward and backward compatibility for applications that follow the rules listed under "Flow key compatibility" above. -The basic rule is obvious: +The basic rule is obvious:: - ------------------------------------------------------------------ + ================================================================== New network protocol support must only supplement existing flow key attributes. It must not change the meaning of already defined flow key attributes. - ------------------------------------------------------------------ + ================================================================== This rule does have less-obvious consequences so it is worth working through a few examples. Suppose, for example, that the kernel module did not already implement VLAN parsing. Instead, it just interpreted the 802.1Q TPID (0x8100) as the Ethertype then stopped parsing the packet. The flow key for any packet with an 802.1Q header would look -essentially like this, ignoring metadata: +essentially like this, ignoring metadata:: eth(...), eth_type(0x8100) @@ -172,7 +175,7 @@ Naively, to add VLAN support, it makes sense to add a new "vlan" flow key attribute to contain the VLAN tag, then continue to decode the encapsulated headers beyond the VLAN tag using the existing field definitions. With this change, a TCP packet in VLAN 10 would have a -flow key much like this: +flow key much like this:: eth(...), vlan(vid=10, pcp=0), eth_type(0x0800), ip(proto=6, ...), tcp(...) @@ -187,7 +190,7 @@ across kernel versions even though it follows the compatibility rules. The solution is to use a set of nested attributes. This is, for example, why 802.1Q support uses nested attributes. A TCP packet in -VLAN 10 is actually expressed as: +VLAN 10 is actually expressed as:: eth(...), eth_type(0x8100), vlan(vid=10, pcp=0), encap(eth_type(0x0800), ip(proto=6, ...), tcp(...))) @@ -215,14 +218,14 @@ For example, consider a packet that contains an IP header that indicates protocol 6 for TCP, but which is truncated just after the IP header, so that the TCP header is missing. The flow key for this packet would include a tcp attribute with all-zero src and dst, like -this: +this:: eth(...), eth_type(0x0800), ip(proto=6, ...), tcp(src=0, dst=0) As another example, consider a packet with an Ethernet type of 0x8100, indicating that a VLAN TCI should follow, but which is truncated just after the Ethernet type. The flow key for this packet would include -an all-zero-bits vlan and an empty encap attribute, like this: +an all-zero-bits vlan and an empty encap attribute, like this:: eth(...), eth_type(0x8100), vlan(0), encap() |