This is mainly a massive renaming in the code to get it in line with the
calling convention. Next patch will rename a few files to complete this
operation.
It's important to report the faulty argument position and to distinguish
between empty arguments and wrong ones.
Integers were not properly tested either, now their parsing has been improved
to report use of incorrect characters.
All parsing errors were known but impossible to return. Now by making use
of memprintf(), we're able to build meaningful error messages that the
caller can display.
It's easy to merge pattern and ACL fetches of cookies. It allows us
to remove two distinct fetch functions. The new function internally
uses an occurrence number to serve both purposes, but it didn't appear
worth exposing it outside so there is no keyword argument to set it.
However one of the benefits is that the "cookie" fetch for stick tables
now automatically adapts to requests and responses, so there is no more
need for set-cookie().
HTTP header fetch is now done using smp_fetch_hdr() for both ACLs and
patterns. This one also supports an occurrence number, making it possible
to specify explicit occurrences for ACLs and patterns.
This way, fetch functions will be able to tell if they're called for a single
request or as part of a loop. This is important for instance when we use
hdr(foo), because in an ACL this means that all hdr(foo) occurrences must
be checked while in a pattern it means only one of them (eg: last one).
pattern_fetch_rdp_cookie() is useless now since it only used to add controls
on top of smp_fetch_rdp_cookie() which have now been integrated into the
pattern subsystem. Let's remove it.
Pattern fetch functions currently check for unstable data and return 0
when SMP_F_MAY_CHANGE is set. Instead of doing this everywhere and having
to support specific fetch functions, better do that in pattern_process()
which is the one interested in having stable data.
Right now, it's up to each pattern fetch method to return NULL when an
empty string is returned, which is neither correct nor desirable as it
is only stick tables which need to ignore empty patterns. Let's perform
this check in stktable_fetch_key() instead.
A test was already performed which worked by pure luck due to integer types,
otherwise it would have been possible to start checking for an offset out of
the buffer's bounds if the buffer size was large enough to allow an integer
wrap. Let's perform explicit checks and use unsigned ints for offsets instead
of risking being hit later.
These ones were easy to adapt to ACL usage and may really be useful,
so let's make them available right now. It's likely that some extension
such as regex, string-to-IP and raw IP matching will be implemented in
the near future.
Since pattern_process() is able to automatically cast returned types
into expected types, we can safely use the sample functions to fetch
addresses whatever their family. The lowest castable type must be
declared with the keyword so that config checks pass.
Right now this means that src/dst use the same fetch function for ACLs
and patterns. src6/dst6 have been kept so that configs which explicitly
rely on v6 are properly checked.
We want to ensure that a dynamically returned type will always have a
cast before calling the cast function. This is done in pattern_process()
and in stktable_fetch_key().
src_port, dst_port and url_param have converged between ACLs and patterns.
This means that src_port is now available in patterns and that urlp_* has
been added to ACLs. Some code has moved to accommodate for static function
definitions, but there were little changes.
Patterns were using a bitmask to indicate if request or response was desired
in fetch functions and keywords. ACLs were using a bitmask in fetch keywords
and a single bit in fetch functions. ACLs were also using an ACL_PARTIAL bit
in fetch functions indicating that a non-final fetch was performed, which was
an abuse of the existing direction flag.
The change now consists in using :
- a capabilities field for fetch keywords => SMP_CAP_REQ/RES to indicate
if a keyword supports requests, responses, both, etc...
- an option field for fetch functions to indicate what the caller expects
(request/response, final/non-final)
The ACL_PARTIAL bit was reversed to get SMP_OPT_FINAL as it's more explicit
to know we're working on a final buffer than on a non-final one.
ACL_DIR_* were removed, as well as PATTERN_FETCH_*. L4 fetches were improved
to support being called on responses too since they're still available.
The <dir> field of all fetch functions was changed to <opt> which is now
unsigned.
The patch is large but mostly made of cosmetic changes to accomodate this, as
almost no logic change happened.
The former was only a wrapper to the second, let's remove it now that
the calling convention is exactly the same. This is the first function
to be unified between ACLs and samples.
Having the args everywhere will make it easier to share fetch functions
between patterns and ACLs. The only place where we could have needed
the expr was in the http_prefetch function which can do well without.
Previously, both pattern, backend and persist_rdp_cookie would build fake
ACL expressions to fetch an RDP cookie by calling acl_fetch_rdp_cookie().
Now we switch roles. The RDP cookie fetch function is provided as a sample
fetch function that all others rely on, including ACL. The code is exactly
the same, only the args handling moved from expr->args to args. The code
was moved to proto_tcp.c, but probably that a dedicated file would be more
suited to content handling.
We need the pattern fetchers and converters to correctly set the output type
so that they can be used by ACL fetchers. By using the sample type instead of
the keyword type, we also open the possibility to create some multi-type
pattern fetch methods later (eg: "src" being v4/v6). Right now the type in
the keyword is used to validate the configuration.
Now there is no more reference to union pattern_data. All pattern fetch and
conversion functions now make use of the common sample type. Note: none of
them adjust the type right now so it's important to do it next otherwise
we would risk sharing such functions with ACLs and seeing them fail.
This change is pretty minor. Struct pattern is only used for
pattern_process() now so changing it to use the common type is
quite obvious. It's worth noting that the last argument of
pattern_process() is never used so the function is self-sufficient.
Note that pattern_process() does not initialize the pattern at all
before calling fetch->process(), and that minimal initialization
will be required when we later change the argument for the sample.
These ones were either unused or improperly used. Some integers were marked
read-only, which does not make much sense. Buffers are not read-only, they're
"constant" in that they must be kept intact after any possible change.
This one is not needed anymore as we can return the data and its type in the
sample provided by the caller. ACLs now always return the proper type. BOOL
is already returned when the result is expected to be processed as a boolean.
temp_pattern has been unexported now.
The new sample types are necessary for the acl-pattern convergence.
These types are boolean and signed int. Some types were renamed for
less ambiguity (ip->ipv4, integer->uint).
The pattern type is ambiguous because a pattern is only a type and a data
part, and is normally used to match against samples. Currently, patterns
cannot hold information related to the life of the data which was extracted.
We don't want to overload patterns either, so let's add a new "sample" type
which will progressively supersede the acl_test and maybe the pattern at most
places. The sample shares similar information with patterns and also has flags
describing the data volatility and protection.
This flag was used to force a boolean match even if there was no pattern
to match. It was used only by http_auth() and designed only for this one.
It's easier and cleaner to make the fetch function perform the test and
report the boolean result as a few other functions already do. It simplifies
the acl_exec_cond() logic and will help merging ACLs and patterns.
The argument parser knows what exact error it has faced, and the pattern
parser is able to report errors, so let's make use of it. From now on, it
becomes possible to detect such things :
$ ./haproxy -db -f echo5.cfg
[ALERT] 110/160344 (4791) : parsing [echo5.cfg:38] : 'stick': invalid arg 2 in fetch method 'payload' : Missing arguments (got 1/2), type 'unsigned integer' expected.
[ALERT] 110/160344 (4791) : parsing [echo5.cfg:39] : 'stick': invalid args in fetch method 'payload' : payload length must be > 0.
[ALERT] 110/160344 (4791) : parsing [echo5.cfg:40] : 'stick': invalid arg 3 in fetch method 'payload_lv' : Failed to parse 'x' as type 'signed integer'.
[ALERT] 110/160344 (4791) : parsing [echo5.cfg:41] : 'stick': invalid arg 4 in fetch method 'payload_lv' : End of arguments expected at ',13'.
[ALERT] 110/160344 (4791) : Error(s) found in configuration file : echo5.cfg
[ALERT] 110/160344 (4791) : Fatal errors found in configuration.
This is used to validate that arguments are coherent. For instance,
payload_lv expects that the last arg (if any) is not more negative
than the sum of the first two. The error is reported if any.
We don't need the pattern-specific args parsers anymore, make use of the
common parser instead. We still need to improve this by adding a validation
function to report abnormal argument values or combinations. We don't report
precise parsing errors yet but this was not previously done either.
arg_i was almost unused, and since we migrated to use struct arg everywhere,
the rare cases where arg_i was needed could be replaced by switching to
arg->type = ARGT_STOP.
A large number of ACLs make use of frontend, backend or table names in their
arguments, and fall back to the current proxy when no argument is passed. If
the expected capability is not available, the ACL silently fails at runtime.
Now we make all those names mandatory in the parser and we rely on
acl_find_targets() to replace the missing names with the holding proxy,
then to perform the appropriate tests, and to reject errors at parsing
time.
It is possible that some faulty configurations will get rejected from now
on, while they used to silently fail till now. This is the reason why this
change is marked as MAJOR.
Proxy names are now resolved when the config is parsed and not at runtime.
This means that errors will be caught for real instead of having an ACL
silently never match. Another benefit is that the fetch will be much faster
since the lookup will not have to be performed anymore, eg for all ACLs
based on explicitly named stick-tables.
However some buggy configurations which used to silently fail in the past
will now refuse to load, hence the MAJOR tag.
This function does not rely on the keyword anymore but just on its type.
It's much cleaner and much safer. It should be extended to do the same for
all PRX type arguments.
The types and minimal number of ACL keyword arguments are now stored in
their declaration. This will allow many more fantasies if some ACL use
several arguments or types.
Doing so required to rework all ACL keyword declarations to add two
parameters. So this was a good opportunity for a general cleanup and
to sort all entries in alphabetical order.
We still have two pending issues :
- parse_acl_expr() checks for errors but has no way to report them to
the user ;
- the types of some arguments are still not resolved and kept as strings
(eg: ARGT_FE/BE/TAB) for compatibility reasons, which must be resolved
in acl_find_targets()
The ACL parser now uses the argument parser to build a typed argument list.
Right now arguments are all strings and only one argument is supported since
this is what ACLs currently support.
make_arg_list() builds an array of typed arguments with their values,
that the caller describes how to parse. This will be used to support
multiple arguments for ACLs and patterns, which is currently problematic
and prevents ACLs and patterns from being merged. Up to 7 arguments types
may be enumerated in a single 32-bit word, including their number of
mandatory parts.
At the moment, these files are not used yet, they're only built. Note that
the 4-bit encoding for the type has left only one unused type!
Latest changes have made it possible to remove all differences between
request and response processing, making it worth merging request and
response ACL fetch functions to reduce code size.
Most likely with minor adaptation it will be possible to use the same hdr_*
functions to match in the response path, and cook_* for the response cookie
too.
ACLs are volatile since they require a fetch of request buffer data which is
then copied to a temporary shared place. The issue is minor though since auth
is generally checked very early.
All ACLs which need to process HTTP contents first call this function which
performs all the preliminary tests and also triggers the request parsing if
needed. A macro was written to simplify the code.
As a side effect, it's not required anymore to check for the HTTP ACL before
checking for HTTP contents.
This function will be called by all ACL fetch functions. Right now all ACL
fetch functions have to perform the exact same tests to check whether data
are available. Also, only one of them is able to actually parse an HTTP
request.
Using the prefetch function, it will be possible to try to parse a request
on the fly and to avoid the fetch if some data are missing. This will
significantly reduce the amount of tests in all ACL fetch functions.
Willy Tarreau