in networking, hitting a timeout requires that *nothing* happens during the
interval. whenever anything happens, the timeout is reset.
there's no need to do custom time calculations, it's perfectly fine to let
the kernel handle it using the select() syscall.
additionally the code added in 0b9a74c290
assures that read and write syscalls() don't block indefinitely and return
on the timeout too, so there's no need to switch sockets back and forth
between blocking/nonblocking.
as a side effect of not updating the config pointer when loading
the config file fails, the "FIXME" level comment to take appropriate
action in that case has been removed. the only issue remaining
when receiving a SIGHUP and encountering a malformed config file would
now be the case that output to syslog/logfile won't be resumed, if
initially so configured.
this is required so we can elegantly swap out an old config for a
new one in the future and remove lots of boilerplate from config
initialization code.
unfortunately this is a quite intrusive change as the config struct
was accessed in numerous places, but frankly it should have been
done via a pointer right from the start.
right now, we simply point to a static struct in main.c, so there
shouldn't be any noticeable changes in behaviour.
it is quite easy to bring down a proxy server by forcing it to make
connections to one of its own ports, because this will result in an endless
loop spawning more and more connections, until all available fds are exhausted.
since there's a potentially infinite number of potential DNS/ip addresses
resolving to the proxy, it is impossible to detect an endless loop by simply
looking at the destination ip address and port.
what *is* possible though is to record the ip/port tuples assigned to outgoing
connections, and then compare them against new incoming connections. if they
match, the sender was the proxy itself and therefore needs to reject that
connection.
fixes#199.
tinyproxy used to do a full hostname resolution whenever a new client
connection happened, which could cause very long delays (as reported in #198).
there's only a single place/scenario that actually requires a hostname, and
that is when an Allow/Deny rule exists for a hostname or domain, rather than
a raw IP address. since it is very likely this feature is not very widely used,
it makes absolute sense to only do the costly resolution when it is unavoidable.
the existing codebase used an elaborate and complex approach for
its parallelism:
5 different config file options, namely
- MaxClients
- MinSpareServers
- MaxSpareServers
- StartServers
- MaxRequestsPerChild
were used to steer how (and how many) parallel processes tinyproxy
would spin up at start, how many processes at each point needed to
be idle, etc.
it seems all preforked processes would listen on the server port
and compete with each other about who would get assigned the new
incoming connections.
since some data needs to be shared across those processes, a half-
baked "shared memory" implementation was provided for this purpose.
that implementation used to use files in the filesystem, and since
it had a big FIXME comment, the author was well aware of how hackish
that approach was.
this entire complexity is now removed. the main thread enters
a loop which polls on the listening fds, then spins up a new
thread per connection, until the maximum number of connections
(MaxClients) is hit. this is the only of the 5 config options
left after this cleanup. since threads share the same address space,
the code necessary for shared memory access has been removed.
this means that the other 4 mentioned config option will now
produce a parse error, when encountered.
currently each thread uses a hardcoded default of 256KB per thread
for the thread stack size, which is quite lavish and should be
sufficient for even the worst C libraries, but people may want
to tweak this value to the bare minimum, thus we may provide a new
config option for this purpose in the future.
i suspect that on heavily optimized C libraries such a musl, a
stack size of 8-16 KB per thread could be sufficient.
since the existing list implementation in vector.c did not provide
a way to remove a single item from an existing list, i added my
own list implementation from my libulz library which offers this
functionality, rather than trying to add an ad-hoc, and perhaps
buggy implementation to the vector_t list code. the sblist
code is contained in an 80 line C file and as simple as it can get,
while offering good performance and is proven bugfree due to years
of use in other projects.
it was reported that because the fdset was only initialized once,
tinyproxy would fail to properly listen on more than one interface.
closes#214closes#127
This was accidentially used instead of the function parameter listen_addrs
This still belongs to the fix for bug BB#63.
Signed-off-by: Michael Adam <obnox@samba.org>
check the return code of fcntl via socket_nonblocking
on the listen sockets in child_main()
Found by coverity.
Signed-off-by: Michael Adam <obnox@samba.org>
This prepares listenting on multiple sockets, which will be ussed to
fix listening on the wildcard (listen on both ipv6 and ipv4) and
help add the support for multiple Listen statements in the config
Signed-off-by: Michael Adam <obnox@samba.org>
instead of using config.ipAddr internally.
This is in preparation to make it possible
to call it for multiple addresses.
Signed-off-by: Michael Adam <obnox@samba.org>
This changes listen_sock() to not return the
addrlen of the used address from getaddrinfo call
to the caller, stored in global addrlen in child.c.
This was only used to be able to allocate enough space for the
arguments to the later accept call depending on whether
IPv4 or IPv6 is used.
This removes the need to pass this info by always allocating
sizeof(struct sockaddr_storage) instead, which is enough
to carry both sockaddr_in and sockaddr_in6.
Signed-off-by: Michael Adam <obnox@samba.org>
Logging is re-initialized by reload_config() now.
And truncation is wrong anyways: A syslog mechanism will
move the current log file and the reopen-action will just
create a new empty log file upon SIGHUP.
Michael
The modified files were indented with GNU indent using the
following command:
indent -npro -kr -i8 -ts8 -sob -l80 -ss -cs -cp1 -bs -nlps -nprs -pcs \
-saf -sai -saw -sc -cdw -ce -nut -il0
No other changes of any sort were made.
The notices have been changed to a more GNU look. Documentation
comments have been separated from the copyright header. I've tried to
keep all copyright notices intact. Some author contact details have
been updated.
I re-indented the source code using indent with the following options:
indent -kr -bad -bap -nut -i8 -l80 -psl -sob -ss -ncs
There are now _no_ tabs in the source files, and all indentation is
eight spaces. Lines are 80 characters long, and the procedure type is
on it's own line. Read the indent manual for more information about
what each option means.
cleanly using a C++ compiler.
Changed the servers_waiting variable to an unsigned int, since the
number of servers waiting can never be negative, and added an assert()
to ensure this invariant.
