1 # Copyright (C) 2015-2020 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;
8 use base 'PublicInbox::DS';
9 use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY);
10 use fields qw(post_accept);
12 use PublicInbox::Syscall qw(EPOLLIN EPOLLEXCLUSIVE EPOLLET);
13 use Errno qw(EAGAIN ECONNABORTED EPERM);
15 # Warn on transient errors, mostly resource limitations.
16 # EINTR would indicate the failure to set NonBlocking in systemd or similar
18 eval("Errno::$_()") => $_
19 } qw(EMFILE ENFILE ENOBUFS ENOMEM EINTR);
22 my ($class, $s, $cb) = @_;
23 setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1);
24 setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP
26 my $self = fields::new($class);
27 $self->SUPER::new($s, EPOLLIN|EPOLLET|EPOLLEXCLUSIVE);
28 $self->{post_accept} = $cb;
34 my $sock = $self->{sock} or return;
36 # no loop here, we want to fairly distribute clients
37 # between multiple processes sharing the same socket
38 # XXX our event loop needs better granularity for
39 # a single accept() here to be, umm..., acceptable
40 # on high-traffic sites.
41 if (my $addr = accept(my $c, $sock)) {
42 IO::Handle::blocking($c, 0); # no accept4 :<
43 eval { $self->{post_accept}->($c, $addr, $sock) };
46 } elsif ($! == EAGAIN || $! == ECONNABORTED || $! == EPERM) {
47 # EAGAIN is common and likely
48 # ECONNABORTED is common with bad connections
49 # EPERM happens if firewall rules prevent a connection
50 # on Linux (and everything that emulates Linux).
51 # Firewall rules are sometimes intentional, so we don't
52 # warn on EPERM to avoid being too noisy...
54 } elsif (my $sym = $ERR_WARN{int($!)}) {
55 warn "W: accept(): $! ($sym)\n";
57 warn "BUG?: accept(): $!\n";