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b686644ad8
Some people need to inspect contents of TCP requests before
deciding to forward a connection or not. A future extension
of this demand might consist in selecting a server farm
depending on the protocol detected in the request.
For this reason, a new state CL_STINSPECT has been added on
the client side. It is immediately entered upon accept() if
the statement "tcp-request inspect-delay <xxx>" is found in
the frontend configuration. Haproxy will then wait up to
this amount of time trying to find a matching ACL, and will
either accept or reject the connection depending on the
"tcp-request content <action> {if|unless}" rules, where
<action> is either "accept" or "reject".
Note that it only waits that long if no definitive verdict
can be found earlier. That generally implies calling a fetch()
function which does not have enough information to decode
some contents, or a match() function which only finds the
beginning of what it's looking for.
It is only at the ACL level that partial data may be processed
as such, because we need to distinguish between MISS and FAIL
*before* applying the term negation.
Thus it is enough to add "| ACL_PARTIAL" to the last argument
when calling acl_exec_cond() to indicate that we expect
ACL_PAT_MISS to be returned if some data is missing (for
fetch() or match()). This is the only case we may return
this value. For this reason, the ACL check in process_cli()
has become a lot simpler.
A new ACL "req_len" of type "int" has been added. Right now
it is already possible to drop requests which talk too early
(eg: for SMTP) or which don't talk at all (eg: HTTP/SSL).
Also, the acl fetch() functions have been extended in order
to permit reporting of missing data in case of fetch failure,
using the ACL_TEST_F_MAY_CHANGE flag.
The default behaviour is unchanged, and if no rule matches,
the request is accepted.
As a side effect, all layer 7 fetching functions have been
cleaned up so that they now check for the validity of the
layer 7 pointer before dereferencing it.
36 lines
1.1 KiB
INI
36 lines
1.1 KiB
INI
# This is a test configuration. It listens on port 8025, waits for an incoming
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# connection, and applies the following rules :
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# - if the address is in the white list, then accept it and forward the
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# connection to the server (local port 25)
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# - if the address is in the black list, then immediately drop it
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# - otherwise, wait up to 3 seconds. If the client talks during this time,
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# drop the connection.
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# - then accept the connection if it passes all the tests.
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#
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# Note that the rules are evaluated at every new chunk of data read, and at
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# delay expiration. Rules which apply to incomplete data don't match as long
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# as the timer has not expired.
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listen block-fake-mailers
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log 127.0.0.1:514 local0
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option tcplog
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mode tcp
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bind :8025
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timeout client 6s
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timeout server 6s
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timeout connect 6s
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tcp-request inspect-delay 4s
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acl white_list src 127.0.0.2
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acl black_list src 127.0.0.3
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acl talkative req_len gt 0
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tcp-request content accept if white_list
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tcp-request content reject if black_list
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tcp-request content reject if talkative
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balance roundrobin
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server mail 127.0.0.1:25
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