1 # Copyright (C) 2015-2021 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # Used by -nntpd for listen sockets
5 package PublicInbox::Listener;
7 use parent 'PublicInbox::DS';
8 use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY);
10 use PublicInbox::Syscall qw(EPOLLIN EPOLLEXCLUSIVE);
11 use Errno qw(EAGAIN ECONNABORTED);
13 # Warn on transient errors, mostly resource limitations.
14 # EINTR would indicate the failure to set NonBlocking in systemd or similar
16 eval("Errno::$_()") => $_
17 } qw(EMFILE ENFILE ENOBUFS ENOMEM EINTR);
20 my ($class, $s, $cb) = @_;
21 setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1);
22 setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP
23 listen($s, 2**31 - 1); # kernel will clamp
24 my $self = bless { post_accept => $cb }, $class;
25 $self->SUPER::new($s, EPOLLIN|EPOLLEXCLUSIVE);
30 my $sock = $self->{sock} or return;
32 # no loop here, we want to fairly distribute clients
33 # between multiple processes sharing the same socket
34 # XXX our event loop needs better granularity for
35 # a single accept() here to be, umm..., acceptable
36 # on high-traffic sites.
37 if (my $addr = accept(my $c, $sock)) {
38 IO::Handle::blocking($c, 0); # no accept4 :<
39 eval { $self->{post_accept}->($c, $addr, $sock) };
41 } elsif ($! == EAGAIN || $! == ECONNABORTED) {
42 # EAGAIN is common and likely
43 # ECONNABORTED is common with bad connections
45 } elsif (my $sym = $ERR_WARN{int($!)}) {
46 warn "W: accept(): $! ($sym)\n";
48 warn "BUG?: accept(): $!\n";