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https://issues.apache.org/jira/browse/TS-4703?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15470788#comment-15470788
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Susan Hinrichs commented on TS-4703:
------------------------------------
[~amc]'s proposal that was sent around on [email protected] and is
the description of the API.
.. include:: ../../../common.defs
.. default-domain:: c
TSClientProtocolStack
*********************
Synopsis
========
`#include <ts/ts.h>`
.. function:: TSReturnCode TSHttpTxnClientProtocolStackGet(TSHttpTxn txnp, int
n, char const** result, int* actual)
.. function:: TSReturnCode TSHttpSsnClientProtocolStackGet(TSHttpSsn ssnp, int
n, char const** result, int* actual)
.. function:: int TSHttpTxnClientProtocolStackContains(TSHttpTxn txnp, char
const** tag)
.. function:: int TSHttpSsnClientProtocolStackContains(TSHttpSsn ssnp, char
const** tag)
.. function:: char const* TSNormalizedProtocolTag(char const* tag)
.. function:: char const* TSRegisterProtocolTag(char const* tag)
Description
===========
These functions are used to explore the protocol stack of the client (user
agent) connection to |TS|. The functions
:func:`TSHttpTxnClientProtocolStackGet` and
:func:`TSHttpSsnClientProtocolStackGet` can be used to retrieve the entire
protocol stack for the user agent connection.
:func:`TSHttpTxnClientProtocolStackContains` and
:func:`TSHttpSsnClientProtocolStackContains` will check for a specific protocol
:arg:`tag` being present in the stack.
Each protocol is represented by tag which is a null terminated string. A
particular tag will always be returned as the same character pointer and so
protocols can be reliably checked with pointer comparisons.
:func:`TSNormalizedProtocolTag` will return this character pointer for a
specific :arg:`tag`. A return value of :const:`NULL` indicates the provided
:arg:`tag` is not registered as a known protocol tag.
:func:`TSRegisterProtocolTag` registers the :arg:`tag` and then returns its
normalized value. This is useful for plugins that provide custom protocols for
user agents.
The protocols are ordered from higher level protocols to the lower level ones
on which the higher operate. For instance a stack might look like
"http/1.1,tls/1.2,tcp,ipv4". For :func:`TSHttpTxnClientProtocolStackGet` and
:func:`TSHttpSsnClientProtocolStackGet` these values are placed in the array
:arg:`result`. :arg:`count` is the maximum number of elements of :arg:`result`
that may be modified by the function call. If :arg:`actual` is not
:const:`NULL` then the actual number of elements in the protocol stack will be
returned. If this is equal or less than :arg:`count` then all elements were
returned. If it is larger then some layers were omitted from :arg:`result`. If
the full stack is required :arg:`actual` can be used to resize :arg:`result` to
be sufficient to hold all of the elements and the function called again with
updated :arg:`count` and :arg:`result`. In practice the maximum number of
elements will is almost certain to be less than 10 which therefore should
suffice. These functions return :const:`TS_SUCCESS` on success and
:const:`TS_ERROR` on failure which should only occurr if :arg:`txnp` or
:arg:`ssnp` are invalid.
The :func:`TSHttpTxnClientProtocolStackContains` and
:func:`TSHttpSsnClientProtocolStackContains` functions are provided for the
convenience when only the presence of a protocol is of interest, not its
location or the presence of other protocols. These functions return 0 if the
protocol :arg:`tag` is not present, non-zero if it is present. The strings are
matched with an anchor prefix search, as with debug tags. For instance if
:arg:`tag` is "tls" then it will match "tls/1.2" or "tls/1.3". This makes
checking for TLS or IP more convenient. If more precision is required the
entire protocol stack can be retrieved and processed more thoroughly.
The protocol tags defined by |TS|.
=========== =========
Protocol Tag
=========== =========
HTTP/1.1 http/1.1
HTTP/1.0 http/1.0
HTTP/2 h2
WebSocket ws
TLS 1.3 tls/1.3
TLS 1.2 tls/1.2
TCP tcp
UDP udp
IPv4 ipv4
IPv6 ipv6
QUIC quic
=========== =========
.. note::
What should HTTP/2 connections return as the top protocol? There are several
options
* "http/1.1,h2"
* "h2"
* "http/1.1,h2" for transctions and "h2" for sessions.
> Adds an API call to retrieve transaction protocol
> -------------------------------------------------
>
> Key: TS-4703
> URL: https://issues.apache.org/jira/browse/TS-4703
> Project: Traffic Server
> Issue Type: Improvement
> Components: TS API
> Reporter: Petar Penkov
> Assignee: Alan M. Carroll
> Fix For: 7.0.0
>
> Time Spent: 2h 40m
> Remaining Estimate: 0h
>
> It would be useful if there was a way to retrieve the underlying protocol for
> a given transaction through the tsapi at the very least for plugin logging
> purposes. This can be achieved with a very simple method since this
> information is already available internally.
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