This patch adds two new variables: fastinter and downinter.
When server state is:
- non-transitionally UP -> inter (no change)
- transitionally UP (going down), unchecked or transitionally DOWN (going up) -> fastinter
- down -> downinter
It allows to set something like:
server sr6 127.0.51.61:80 cookie s6 check inter 10000 downinter 20000 fastinter 500 fall 3 weight 40
In the above example haproxy uses 10000ms between checks but as soon as
one check fails fastinter (500ms) is used. If server is down
downinter (20000) is used or fastinter (500ms) if one check pass.
Fastinter is also used when haproxy starts.
New "timeout.check" variable was added, if set haproxy uses it as an additional
read timeout, but only after a connection has been already established. I was
thinking about using "timeout.server" here but most people set this
with an addition reserve but still want checks to kick out laggy servers.
Please also note that in most cases check request is much simpler
and faster to handle than normal requests so this timeout should be smaller.
I also changed the timeout used for check connections establishing.
Changes from the previous version:
- use tv_isset() to check if the timeout is set,
- use min("timeout connect", "inter") but only if "timeout check" is set
as this min alone may be to short for full (connect + read) check,
- debug code (fprintf) commented/removed
- documentation
Compile tested only (sorry!) as I'm currently traveling but changes
are rather small and trivial.
The documentation now lists all keywords except the req* and rsp*. The
"server" keyword has been documented for mandatory parameters. Specific
settings are still waiting to be written in a dedicated section.
Using some Linux kernel patches, it is possible to redirect non-local
traffic to local sockets when IP forwarding is enabled. In order to
enable this option, we introduce the "transparent" option keyword on
the "bind" command line. It will make the socket reachable by remote
sources even if the destination address does not belong to the machine.
- options tcplog, tcpsplice and transparent have been documented.
- keywords "srvtimeout", "timeout queue", "timeout server" and
"timeout tarpit" have been documented
- keywords "transparent" and "use_backend" have been documented
Only "server", "source" and "stats *" remain undocumented
Options nolinger, persist, smtpchk and ssl-hello-chk have been
documented. All keywords and options up to and including option
tcpka are now documented.
This patch extends a little previously added functionality to also
count retries and redispatches for servers. Now it is possible to know
which server causes redispatches as it is not always the same that takes
most retries.
While working with the code I found that redistribute_pending() does not increment
srv->redispatches && be->redispatches. I don't know how to test it but
I think the fix is correct. If not I can withdraw it.
I also extended logs to show how many retries were done and if redispatching
was necessary ('+'). I'm using an additional session flag SN_REDISP to match
redispatched connections. I had to rearrange all defines in session.h to make
more room for it.
The documentation about logs was also fixed a little (sorry, english only),
as current version uses totally different format. BTW: examples are still
outdated, maybe next time...
Finally, I changed %d -> %u for retries/redispatches as those variables
are declared as unsigned.
In order to offer DoS protection, it may be required to lower the maximum
accepted time to receive a complete HTTP request without affecting the client
timeout. This helps protecting against established connections on which
nothing is sent. The client timeout cannot offer a good protection against
this abuse because it is an inactivity timeout, which means that if the
attacker sends one character every now and then, the timeout will not
trigger. With the HTTP request timeout, no matter what speed the client
types, the request will be aborted if it does not complete in time.
This new parameter makes it possible to override the default
number of consecutive incoming connections which can be
accepted on a socket. By default it is not limited on single
process mode, and limited to 8 in multi-process mode.
Add the "backlog" parameter to frontends, to give hints to
the system about the approximate listen backlog desired size.
In order to protect against SYN flood attacks, one solution is
to increase the system's SYN backlog size. Depending on the
system, sometimes it is just tunable via a system parameter,
sometimes it is not adjustable at all, and sometimes the system
relies on hints given by the application at the time of the
listen() syscall. By default, HAProxy passes the frontend's
maxconn value to the listen() syscall. On systems which can
make use of this value, it can sometimes be useful to be able
to specify a different value, hence this backlog parameter.
It is sometimes required to know some informations such as the
process uptime when consulting statistics. This patch adds the
"show info" command to query those informations on the UNIX
socket.
This patch adds a possibility to invert most of available options by
introducing the "no" keyword, available as an additional prefix.
If it is found arguments are shifted left and an additional flag (inv)
is set.
It allows to use all options from a current defaults section, except
the selected ones, for example:
-- cut here --
defaults
contimeout 4200
clitimeout 50000
srvtimeout 40000
option contstats
listen stats 1.2.3.4:80
no option contstats
-- cut here --
Currenly inversion works only with the "option" keyword.
The patch also moves last_checks calculation at the end of the readcfgfile()
function and changes "PR_O_FORCE_CLO | PR_O_HTTP_CLOSE" into "PR_O_FORCE_CLO"
in cfg_opts so it is possible to invert forceclose without breaking httpclose
(and vice versa) and to invert tcpsplice in one proxy but to keep a proper
last_checks value when tcpsplice is used in another proxy. Now, the code
checks for PR_O_FORCE_CLO everywhere it checks for PR_O_HTTP_CLOSE.
I also decided to depreciate "redisp" and "redispatch" keywords as it is IMHO
better to use "option redispatch" which can be inverted.
Some useful documentation were added and at the same time I sorted
(alfabetically) all valid options both in the code and the documentation.
New in this version is a small intro to HTTP, then a detailed
explanation of the following keywords :
acl, appsession, balance, bind, block, capture cookie,
capture request header, capture response header, clitimeout,
contimeout, cookie, default_backend, disabled, enabled, errorfile,
http-check disable-on-404, monitor fail, option contstats,
timeout client, timeout clitimeout, timeout connect,
timeout contimeout.
Others will be alphabetically added.
The code in haproxy-1.3.13.1 only supports syslogging to an internet
address. The attached patch:
- Adds support for syslogging to a UNIX domain socket (e.g., /dev/log).
If the address field begins with '/' (absolute file path), then
AF_UNIX is used to construct the socket. Otherwise, AF_INET is used.
- Achieves clean single-source build on both Mac OS X and Linux
(sockaddr_in.sin_len and sockaddr_un.sun_len field aren't always present).
For handling sendto() failures in send_log(), it appears that the existing
code is fine (no need to close/recreate socket) for both UDP and UNIX-domain
syslog server. So I left things alone (did not close/recreate socket).
Closing/recreating socket after each failure would also work, but would lead
to increased amount of unnecessary socket creation/destruction if syslog is
temporarily unavailable for some reason (especially for verbose loggers).
Please consider this patch for inclusion into the upstream haproxy codebase.
A new "timeout" keyword replaces old "{con|cli|srv}timeout", and
provides the ability to independantly set the following timeouts :
- client
- tarpit
- queue
- connect
- server
- appsession
Additionally, the "clitimeout", "contimeout" and "srvtimeout" values
are supported but deprecated. No warning is emitted yet when they are
used since the option is very new.
Other timeouts should follow soon now.
Hello,
You will find attached an updated release of previously submitted patch.
It polish some part and extend ACL engine to match IP and PORT parsed in
HTTP request. (and take care of comments made by Willy ! ;))
Best regards,
Alexandre
By default, counters used for statistics calculation are incremented
only when a session finishes. It works quite well when serving small
objects, but with big ones (for example large images or archives) or
with A/V streaming, a graph generated from haproxy counters looks like
a hedgehog.
This patch implements a contstats (continous statistics) option.
When set counters get incremented continuously, during a whole session.
Recounting touches a hotpath directly so it is not enabled by default,
as it has small performance impact (~0.5%).
Some applications do not have a strict persistence requirement, yet
it is still desirable for performance considerations, due to local
caches on the servers. For some reasons, there are some applications
which cannot rely on cookies, and for which the last resort is to use
a parameter passed in the URL.
The new 'url_param' balance method is there to solve this issue. It
accepts a parameter name which is looked up from the URL and which
is then hashed to select a server. If the parameter is not found,
then the round robin algorithm is used in order to provide a normal
load balancing across the servers for the first requests. It would
have been possible to use a source IP hash instead, but since such
applications are generally buried behind multiple levels of
reverse-proxies, it would not provide a good balance.
The doc has been updated, and two regression testing configurations
have been added.
This patch adds the "maxqueue" parameter to the server. This allows new
sessions to be immediately rebalanced when the server's queue is filled.
It's useful when session stickiness is just a performance boost (even a
huge one) but not a requirement.
This should only be used if session affinity isn't a hard functional
requirement but provides performance boost by keeping server-local
caches hot and compact).
Absence of 'maxqueue' option means unlimited queue. When queue gets filled
up to 'maxqueue' client session is moved from server-local queue to a global
one.
Removed old unused MODE_LOG and MODE_STATS, and replaced the "stats"
keyword in the global section. The new "stats" keyword in the global
section is used to create a UNIX socket on which the statistics will
be accessed. The client must issue a "show stat\n" command in order
to get a CSV-formated output similar to the output on the HTTP socket
in CSV mode.
For people who manage many haproxies, it is sometimes convenient
to be informed of their version. This patch adds this, with the
option to disable this report by specifying "stats hide-version".
Also, the feature may be permanently disabled by setting the
STATS_VERSION_STRING to "" (empty string), or the format can
simply be adjusted.
The following patch will give the ability to tweak socket linger mode.
You can use this option with "option nolinger" inside fronted or backend
configuration declaration.
This will help in environments where lots of FIN_WAIT sockets are
encountered.
Sometimes it may be desirable to automatically refresh the
stats page. Most browsers support the "Refresh:" header with
an interval in seconds. Specifying "stats refresh xxx" will
automatically add this header.
This new configuration manual intends to document every known keyword
of the configuration language. Right now, it enumerates them all and
describes how to use ACLs.
It is now possible to read error messages from local files,
using the 'errorfile' keyword. Those files are read during
parsing, so there's no I/O involved. They make it possible
to return custom error messages with custom status and headers.
ACLs now support operators such as 'eq', 'le', 'lt', 'ge' and 'gt'
in order to give more flexibility to the language. Because of this
change, the 'dst_limit' keyword changed to 'dst_conn' and now requires
either a range or a test such as 'dst_conn lt 1000' which is more
understandable.
By default, epoll/kqueue used to return as many events as possible.
This could sometimes cause huge latencies (latencies of up to 400 ms
have been observed with many thousands of fds at once). Limiting the
number of events returned also reduces the latency by avoiding too
many blind processing. The value is set to 200 by default and can be
changed in the global section using the tune.maxpollevents parameter.
Peter van Dijk contributed this patch which implements the "smtpchk"
option, which is to SMTP what "httpchk" is to HTTP. By default, it sends
"HELO localhost" to the servers, and waits for the 250 message, but it
can also send a specific request.
Since the introduction of speculative I/O, it was not always possible
to correctly detect a connection establishment. Particularly, in TCP
mode, there is no data to send and getsockopt() returns no error. The
solution consists in trying a connect() again to get its diagnostic.
The principle behind speculative I/O is to speculatively try to
perform I/O before registering the events in the system. This
considerably reduces the number of calls to epoll_ctl() and
sometimes even epoll_wait(), and manages to increase overall
performance by about 10%.
The new poller has been called "sepoll". It is used by default
on Linux when it works. A corresponding option "nosepoll" and
the command line argument "-ds" allow to disable it.
Patch from Fabrice Dulaunoy. Explanation below, and script
merged in examples/.
This patch allow to put a different address in the check part for each
server (and not only a specific port)
I need this feature because I've a complex settings where, when a specific
farm goes down, I need to switch a set of other farm either if these other
farm behave perfectly well.
For that purpose, I've made a small PERL daemon with some REGEX or PORT
test which allow me to test a bunch of thing.
Patch from Bryan Germann for 1.2.17.
In some circumstances, it is useful not to add the X-Forwarded-For
header, for instance when the client is another reverse-proxy or
stunnel running on the same machine and which already adds it. This
patch adds the "except" keyword to the "forwardfor" option, allowing
to specify an address or network which will not be added to this
header.
Patch from Marcus Rueckert for 1.2.17 :
"I added the attached patch to haproxy. I don't have a static uid/gid for
haproxy so i need to specify the username/groupname to run it as non
root user."
Some parts of HTTP processing were incorrectly called "request" while
they are messages or transactions. The following structure members
have changed :
http_msg.hdr_state => msg_state
http_msg.sor => som
http_req.req_state => removed
http_req => http_txn
The tcp-splicing code has been merged, and a doc has been written.
A configuration example has been derived from the previous content
switching sample.
The new parser uses an FSM to strictly follow RFC2616.
Headers are indexed and parsed only once they're all available.
That way, complex regexes make more sense.
HTTP processing is now performed in several phases by calling
multiple functions, making the code cleaner and easier to read.
Note that req[i]pass does not work anymore because it would
require that we mark a header to be ignored. What is really
needed is to have the ability to add an exception to a matching
(match xx except yy).
Several bugs have been fixed in appsession during the conversion
to the new FSM (method length and recovery on malloc errors).
The code does build and work with the debug examples, but is
not usable yet to connect to anything as it does not forward
the requests yet.
Released 1.3.1 with the following changes from 1.2.15 :
- now, haproxy warns about missing timeout during startup to try to
eliminate all those buggy configurations.
- added "Content-Type: text/html" in responses wherever appropriate, as
suggested by Cameron Simpson.
- implemented "option ssl-hello-chk" to use SSLv3 CLIENT HELLO messages to
test server's health
- implemented "monitor-uri" so that haproxy can reply to a specific URI with
an "HTTP/1.0 200 OK" response. This is useful to validate multiple proxies
at once.
This makes it possible to relay SSL connections in pure TCP instances while
ensuring the remote end really receives our data eventhough intermediate
agents (firewalls, proxies, ...) might acknowledge the connection.
The files are now stored under :
- include/haproxy for the generic includes
- include/types.h for the structures needed within prototypes
- include/proto.h for function prototypes and inline functions
- src/*.c for the C files
Most include files are now covered by LGPL. A last move still needs
to be done to put inline functions under GPL and not LGPL.
Version has been set to 1.3.0 in the code but some control still
needs to be done before releasing.
Released 1.2.14 with the following changes :
- new HTML status report with the 'stats' keyword.
- added the 'abortonclose' option to better resist traffic surges
- implemented dynamic traffic regulation with the 'minconn' option
- show request time on denied requests
- definitely fixed hot reconf on OpenBSD by the use of SO_REUSEPORT
- now a proxy instance is allowed to run without servers, which is
useful to dedicate one instance to stats
- added lots of error counters
- a missing parenthesis preventd matching of cacheable cookies
- a missing parenthesis in poll_loop() might have caused missed events.
When 'minconn' is set, the number of simultaneous sessions sent to the server
will be limited by a dynamic value depending on the global load on the
instance itself. The principle is to fix the maximal concurrency on the server
proportionnally to the instance's usage relative to its maxconn, with a minimum
fixed to <minconn>. The formula for the number of simultaneous sessions sent
to the server is then max(srv_minconn, srv_maxconn*px_conn/px_maxconn). This
helps unloading the servers when the load is very low.
to 'close', but does not actually close any connection. The problem
is, there are some servers which don't close the connection even if
the proxy tells them 'Connection: close'. A workaround was added by
the way of a new option 'forceclose' (which implies 'httpclose'),
and which makes the proxy close the outgoing channel to the server
once it has sent all its headers. Just don't use this with the
'CONNECT' method of course !
were erroneously load-balanced while the doc said the opposite.
Since load-balanced backup servers is one of the features some
people have been asking for, the problem was fixed to reflect the
documented behaviour and a new option 'allbackups' was introduced
to provide the feature to those who need it.
* second batch of socklen_t changes.
* clean-ups from Cameron Simpson.
* because tv_remain() does not know about eternity, using no timeout can
make select() spin around a null time-out. Bug reported by Cameron Simpson.
* client read timeout was not properly set to eternity initialized after an
accept() if it was not set in the config. It remained undetected so long
because eternity is 0 and newly allocated pages are zeroed by the system.
* do not call get_original_dst() when not in transparent mode.
* implemented a workaround for a bug in certain epoll() implementations on
linux-2.4 kernels (epoll-lt <= 0.21).
* implemented TCP keepalive with new options : tcpka, clitcpka, srvtcpka.
* changed the runtime argument to disable epoll() to '-de'
* changed the runtime argument to disable poll() to '-dp'
* added global options 'nopoll' and 'noepoll' to do the same at the
configuration level.
* added a 'linux24e' target to the Makefile for Linux 2.4 systems patched to
support epoll().
* changed default FD_SETSIZE to 65536 on Solaris (default=1024)
* conditionned signals redirection to #ifdef DEBUG_MEMORY
* implemented the HTTP 303 code for error redirection. This forces the
browser to fetch the given URI with a GET request. The new keyword for
this is 'errorloc303', and a new 'errorloc302' keyword has been created
to make them easily distinguishable.
* added more controls in the parser for valid use of '\x' sequence.
* few fixes from Alex & Klaus
* fixed a few errors in the documentation
* do not pre-initialize unused file-descriptors before select() anymore.
* add an architecture guide to the documentation
* released without any changes
* increased default BUFSIZE to 16 kB to accept max headers of 8 kB which is
compatible with Apache. This limit can be configured in the makefile now.
Thanks to Eric Fehr for the checks.
* added a per-server "source" option which now makes it possible to bind to
a different source for each (potentially identical) server.
* changed cookie-based server selection slightly to allow several servers to
share a same cookie, thus making it possible to associate backup servers to
live servers and ease soft-stop for maintenance periods. (Alexander Lazic)
* added the cookie 'prefix' mode which makes it possible to use persistence
with thin clients which support only one cookie. The server name is prefixed
before the application cookie, and restore back.
* fixed the order of servers within an instance to match documentation. Now
the servers are *really* used in the order of their declaration. This is
particularly important when multiple backup servers are in use.
* fixed a bug where a TCP connection would be logged twice if the 'logasap'
option was enabled without the 'tcplog' option.
* encode_string() would use hdr_encode_map instead of the map argument.
* the logged request is now encoded with '#XX' for unprintable characters
* new keywords 'capture request header' and 'capture response header' enable
logging of arbitrary HTTP headers in requests and responses
* removed "-DSOLARIS" after replacing the last inet_aton() with inet_pton()
* added the '-V' command line option to verbosely report errors even though
the -q or 'quiet' options are specified. This is useful with '-c'.
* added a Red Hat init script and a .spec from Simon Matter <simon.matter@invoca.ch>
* added 'rspdeny' and 'rspideny' to block certain responses to avoid sensible
information leak from servers.
* more examples added into the configuration
* the configurable HTTP health check introduced in 1.1.23 revealed a shameful
bug : the code still assumed that HTTP requests were the same size as the
original ones (22 bytes), and failed if they were not.
* added support for pidfiles.
* added the 'tcplog' option, which provides enhanced, HTTP-like logs for
generic TCP proxies, or lighter logs for HTTP proxies.
* fixed a time-out condition wrongly reported as client time-out in data
phase if the client timeout was lower than the connect timeout times the
number of retries.
* doc: added some precisions about the log timers
* if a client sent a full request then shut its write connection down, then
the request was aborted. This case was detected only when using haproxy
both as health-check client and as a server.
* if 'option httpchk' is used in a 'health' mode server, then responses will
change from 'OK' to 'HTTP/1.0 200 OK'.
* fixed a Linux-only bug in case of HTTP server health-checks, where a single
server response followed by a close could be ignored, and the server seen
as failed.
* renamed 'haproxy.txt' to 'haproxy-fr.txt'
* large documentation and examples cleanups
* fixed a stupid bug introduced in 1.1.22 which caused second and subsequent
'default' sections to keep previous parameters, and not initialize logs
correctly.
* fixed a second stupid bug introduced in 1.1.22 which caused configurations
relying on 'dispatch' mode to segfault at the first connection.
* 'option httpchk' now supports method, HTTP version and a few headers.
* now, 'option httpchk', 'cookie' and 'capture' can be specified in
'defaults' section
* a fresh new english documentation
* large Makefile cleanup for increased portability
* new build script 'build.cfg' for Formilux-0.1.8
* new startup script 'init.haproxy.flx0' for Formilux-0.1.8
* 'listen' now supports optionnal address:port-range lists
* 'bind' introduced to add new listen addresses
* fixed a bug which caused a session to be kept established on a server till
it timed out if the client closed during the DATA phase.
* the port part of each server address can now be empty to make the proxy
connect to the server on the same port it was connected to, be an absolute
unsigned number to reflect a single port (as in older versions), or an
explicitly signed number (+N/-N) to indicate that this offset must be
applied to the port the proxy was connected to, when connecting to the
server.
* the 'port' server option allows the user to specify a different
health-check port than the service one. It is mandatory when only relative
ports have been specified and check is required. By default, the checks are
sent to the service port.
* new 'defaults' section which is rather similar to 'listen' except that all
values are only used as default values for future 'listen' sections, until
a new 'defaults' resets them. At the moment, server options, regexes,
cookie names and captures cannot be set in the 'defaults' section.
* Makefile now optimizes for Ultrasparc by default on Solaris/Sparc
* large documentation updates and fixes
* new 'tests' directory with some debug files
* changed the debug output format so that it now includes the session unique
ID followed by the instance name at the beginning of each line.
* in debug mode, accept now shows the client's IP and port.
* added one 3 small debugging scripts to search and pretty print debug output
* changed the default health check request to "OPTIONS /" instead of
"OPTIONS *" since not all servers implement the later one.
* "option httpchk" now accepts an optional parameter allowing the user to
specify and URI other than '/' during health-checks.
* made Makefile more robust to pcre-config errors
* added 3 new pretty-print scripts : debug2ansi, debug2html and debugfind
* upgraded Formilux package to haproxy-1.1.21-flx.1.pkg
* removed the now obsolete haproxy2html.sh
* Haproxy can be compiled with PCRE regex instead of libc regex, by setting
REGEX=pcre on the make command line.
* HTTP health-checks now use "OPTIONS *" instead of "OPTIONS /".
* when explicit source address binding is required, it is now also used for
health-checks.
* added 'reqpass' and 'reqipass' to allow certain headers but not the request
itself.
* factored several strings to reduce binary size by about 2 kB.
* replaced setreuid() and setregid() with more standard setuid() and setgid().
* added 4 status flags to the log line indicating who ended the connection
first, the sessions state, the validity of the cookie, and action taken on
the set-cookie header.
* rearranged the changelog and removed it from haproxy.c
* large documentation updates
* add the notion of "backup" servers, which are used only when all other
servers are down.
* make Set-Cookie return "" instead of "(null)" when the server has no
cookie assigned (useful for backup servers).
* "log" now supports an optionnal level name (info, notice, err ...) above
which nothing is sent.
* replaced some strncmp() with memcmp() for better efficiency.
* added "capture cookie" option which logs client and/or server cookies
* cleaned up/down messages and dump servers states upon SIGHUP
* added a redirection feature for errors : "errorloc <errnum> <url>"
* now we won't insist on connecting to a dead server, even with a cookie,
unless option "persist" is specified.
* added HTTP/408 response for client request time-out and HTTP/50[234] for
server reply time-out or errors.
* updates to the examples files
* added a 'do_status' command to the Formilux init script
* fixed multi-cookie handling in client request to allow clean deletion
in insert+indirect mode. Now, only the server cookie is deleted and not
all the header. Should now be compliant to RFC2109.
* added a "nocache" option to "cookie" to specify that we explicitly want
to add a "cache-control" header when we add a cookie.
It is also possible to add an "Expires: <old-date>" to keep compatibility
with old/broken caches.
* some doc and examples cleanups
* if a cookie is used in insert+indirect mode, it's desirable that the
the servers don't see it. It was not possible to remove it correctly
with regexps, so now it's removed automatically.
* don't use snprintf()'s return value as an end of message since it may
be larger. This caused bus errors and segfaults in internal libc's
getenv() during localtime() in send_log().
* removed dead insecure send_syslog() function and all references to it.
* fixed warnings on Solaris due to buggy implementation of isXXXX().
* option "dontlognull"
* fixed "double space" bug in config parser
* fixed an uninitialized server field in case of dispatch
with no existing server which could cause a segfault during
logging.
* the pid logged was always the father's, which was wrong for daemons.
* fixed wrong level "LOG_INFO" for message "proxy started".
* http logging is now complete :
- ip:port, date, proxy, server
- req_time, conn_time, hdr_time, tot_time
- status, size, request
* source address binding
* connection logging displayed incorrect source address.
* added proxy start/stop and server up/down log events.
* replaced log message short buffers with larger trash.
* enlarged buffer to 8 kB and replace buffer to 4 kB.
* added a config.rc example for Formilux
* added a build script for Formilux
* added OpenBSD, Linux-2.2 and Linux-2.4 targets to the Makefile
* added a Formilux init script
* fixed a few timeout bugs
* rearranged the task scheduler subsystem to improve performance,
add new tasks, and make it easier to later port to librt ;
* allow multiple accept() for one select() wake up ;
* implemented internal load balancing with basic health-check ;
* cookie insertion and header add/replace/delete, with better strings
support.
* reworked buffer handling to fix a few rewrite bugs, and
improve overall performance.
* implement the "purge" option to delete server cookies in direct mode.
* fixed some error cases where the maxfd was not decreased.
* now supports transparent proxying, at least on linux 2.4.
* soft stop works again (fixed select timeout computation).
* it seems that TCP proxies sometimes cannot timeout.
* added a "quiet" mode.
* enforce file descriptor limitation on socket() and accept().
