No evdns will do caching by default (with respect to TTL), to disable this set EVDNS_BASE_NO_CACHE
There are also helpers for manually manage the cache:
- evdns_cache_write()
- evdns_cache_lookup()
Initial PR: #571Fixes: #1715
Co-authored-by: Greg Hazel <ghazel@gmail.com>
Co-authored-by: Keith Moore <kmoore@clostra.com>
DragonFly BSD changed the time unit for TCP keep-alive from milliseconds to seconds since v5.8 and Solaris 11.4 added `TCP_KEEPIDLE`, `TCP_KEEPINTVL`, and `TCP_KEEPCNT` with time units in second while Solaris <11.4 still use `TCP_KEEPALIVE_THRESHOLD` and `TCP_KEEPALIVE_ABORT_THRESHOLD` with time units in millisecond.
Currently, we don't differentiate among DragonFly BSD versions but set the keepalive options with seconds, which will result in unexpected behaviors on DragonFlyBSD <5.8. This PR intends to fix the wrong usage of time units of TCP keepalive options on DragonFly BSD <5.8 and consolidate the logic of time units conversion for TCP keepalive across platforms.
In addition, this PR introduces a new custom macro for determining Solaris 11.4. This macro is expected to help us implement some new features for `libuv` using some abilities that only exist on Solaris 11.4 and other mainstream platforms in the future, considering that Oracle developed and released Solaris 11.4 to replenish plenty of features on Solaris that have already been implemented on other UNIX-like OSs but missing from Solaris <11.4, also bring a good deal of new features.
### References
- [Change tcp keepalive options from ms to seconds (DISRUPTIVE)](https://lists.dragonflybsd.org/pipermail/commits/2019-July/719125.html)
- [DragonFly BSD 5.8 release notes](https://www.dragonflybsd.org/release58/)
- [DragonFly TCP](https://man.dragonflybsd.org/?command=tcp§ion=4)
- [Solaris 11.3 TCP](https://docs.oracle.com/cd/E86824_01/html/E54777/tcp-7p.html)
- [Solaris 11.4 TCP](https://docs.oracle.com/cd/E88353_01/html/E37851/tcp-4p.html)
- [Solaris 11.4 release notes](https://docs.oracle.com/cd/E37838_01/html/E60973/)
Signed-off-by: Andy Pan <i@andypan.me>
Found by oss-fuzz, after coverage had been improved in google/oss-fuzz#11257
v2: adjust test
v3: fix for windows (_get_osfhandle() crashes when called on closed fd)
v4: fix for EVENT__DISABLE_MM_REPLACEMENT
Note, that in order to do this evrpc_hook_add_meta() should have return
value, so this is a minor ABI change, which should not affect C ABI, but
still worth to mention.
Anyway this will be done in 2.2 release and unlikely RPC subsystem is
popular.
Changes:
- Optimize preprocessor directives on Solaris for evutil_set_tcp_keepalive
- Reduce the amount of code being compiled and trim trailing whitespace in passing.
- Move comments for Solaris under its macro
- Refactor the control flow
Default settings of TCP keep-alive are not always feasible,
take Linux for example, the duration a connection needs to be
idle before sending out the first keep-alive probe is two hours,
which makes detecting dead connections extremely deferred. Thus,
enabling TCP keep-alive will be to little avail.
This sets TCP_KEEPIDLE, TCP_KEEPINTVL, and TCP_KEEPCNT when enabling TCP
keep-alive mechanism to make it practicable.
This commit addresses a minor inconsistency identified in the
documentation of multiple `evhttp` callback functions within
the `event2/http.h` header file. It was observed that the word
"additional" was presumably missing in the description of the
`arg` parameter for several functions. This oversight led to
an incorrect phrasing: "an context argument for the callback."
The documentation for the following functions has been updated
to rectify this issue:
- `evhttp_set_gencb`
- `evhttp_set_bevcb`
- `evhttp_set_newreqcb`
- `evhttp_set_errorcb`
This commit solely improves the readability of the function
descriptions without altering any functional aspects of the
code.
This is the same as evbuffer_add_reference(), but allows to specify
offset in the @data
v2: rename evbuffer_add_reference_misalign() to evbuffer_add_reference_with_offset()
Replace evws_send with evws_send_text, and introduce new API -
evws_send_binary, that can be used to send binary frames.
But note, that this commit breaks the ABI compatibility, but it should be OK,
since there was only alpha release with evws_send, and nobody should rely on
this, and I hope nobody does (we decided to go this way to avoid supporting
deprecated API).
signalfd may behave differently to sigaction/signal, so to avoid
breaking libevent users (like [1], [2]) disable it by default.
[1]: https://github.com/tmux/tmux/pull/3621
[2]: https://github.com/tmux/tmux/pull/3626
Also signalfd is not that perfect:
- you need to SIG_BLOCK the signal before
- blocked signals are not reset on exec
- blocked signals are allowed to coalesce - so in case of multiple
signals sent you may get the signal only once (ok for most of the
signals, but may be a problem for SIGCHLD, though you may call
waitpid() in a loop or use pidfd)
- and also one implementation problem -
sigprocmask is unspecified in a multithreaded process
Refs:
- https://lwn.net/Articles/415684/
- https://ldpreload.com/blog/signalfd-is-useless
Refs: https://github.com/libevent/libevent/issues/1460
Refs: #1342 (cc @dmantipov)
When libevent doesn't provide random the arc4 function, but they come from libc, there is no need to call this function, so make it do nothing.
Fixes: #1393
Libevent introduced the LEV_OPT_BIND_IPV6ONLY to pass to evconnlistener_new_bind to make it automatically set the underlying socket as accepting ipv6 requests. This works fine on posix compliant platforms as by the standard every new AF_INET6 socket is created as both supporting ipv6 and ipv4 connections. But on windows the default is the opposite, with the flag IPV6_V6ONLY being always enabled by default.
This makes creating a listener to supports both protocols a bit more tricky as winsock doesn't allow changing this flag after evconnlistener_new_bind does all the initial setup because as stated in the docs, you can't change it after the sonnect connected, so one would have to manually create the socket beforehand and set the flag and then call evconnlistener_new with the socket itself.
It would be nice to have libevent keep a consistent behaviour across the platforms in this scenario, maybe or by making it always set IPV6_V6ONLY to false unless LEV_OPT_BIND_IPV6ONLY is passed, in which case it's set to true, or add another flag to forcefully set it to false and keep the system dependent behaviour as default.
So this patch add new option for libevent listeners to bind to both - LEV_OPT_BIND_IPV4_AND_IPV6
Linux-specific signal handling backend based on signalfd(2)
system call, and public function event_base_get_signal_method()
to obtain an underlying kernel signal handling mechanism.
Signed-off-by: Dmitry Antipov <dantipov@cloudlinux.com>
This adds few functions to use evhttp-based webserver to handle incoming
WebSockets connections. We've tried to use both libevent and libwebsockets in
our application, but found that we need to have different ports at the same
time to handle standard HTTP and WebSockets traffic. This change can help to
stick only with libevent library.
Implementation was inspired by modified Libevent source code in ipush project
[1].
[1]: https://github.com/sqfasd/ipush/tree/master/deps/libevent-2.0.21-stable
Also, WebSocket-based chat server was added as a sample.
There are no standard for encoding a unix socket in an url. nginx uses:
http://unix:/path/to/unix/socket:/httppath
The second colon is needed to delimit where the unix path ends and where
the rest of the url continues.
Signed-off-by: Sean Young <sean@mess.org>
Add new flag (DNS_CNAME_CALLBACK) for
evdns_base_resolve_ipv4()/evdns_base_resolve_ipv6().
If set, you will get one more callback with type == DNS_CNAME and CNAME
in addrs argument.
Looks like a `splice` implementation was planned, but has clearly never
eventuated (the TODO comment is from ~12 years ago, in
8b5bd77415fb6634fadf08357676926fecf5f032). For now, it's probably better
to remove the unused code/correct the docs.
