# Copyright (C) 2015-2021 all contributors # License: AGPL-3.0+ # # Used by -nntpd for listen sockets package PublicInbox::Listener; use strict; use parent 'PublicInbox::DS'; use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY); use IO::Handle; use PublicInbox::Syscall qw(EPOLLIN EPOLLEXCLUSIVE); use Errno qw(EAGAIN ECONNABORTED); # Warn on transient errors, mostly resource limitations. # EINTR would indicate the failure to set NonBlocking in systemd or similar my %ERR_WARN = map {; eval("Errno::$_()") => $_ } qw(EMFILE ENFILE ENOBUFS ENOMEM EINTR); sub new ($$$) { my ($class, $s, $cb) = @_; setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1); setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP listen($s, 2**31 - 1); # kernel will clamp my $self = bless { post_accept => $cb }, $class; $self->SUPER::new($s, EPOLLIN|EPOLLEXCLUSIVE); } sub event_step { my ($self) = @_; my $sock = $self->{sock} or return; # no loop here, we want to fairly distribute clients # between multiple processes sharing the same socket # XXX our event loop needs better granularity for # a single accept() here to be, umm..., acceptable # on high-traffic sites. if (my $addr = accept(my $c, $sock)) { IO::Handle::blocking($c, 0); # no accept4 :< eval { $self->{post_accept}->($c, $addr, $sock) }; warn "E: $@\n" if $@; } elsif ($! == EAGAIN || $! == ECONNABORTED) { # EAGAIN is common and likely # ECONNABORTED is common with bad connections return; } elsif (my $sym = $ERR_WARN{int($!)}) { warn "W: accept(): $! ($sym)\n"; } else { warn "BUG?: accept(): $!\n"; } } 1;