<varlistentry>
<term><varname>Backlog=</varname></term>
- <listitem><para>Takes an unsigned integer argument. Specifies
- the number of connections to queue that have not been accepted
- yet. This setting matters only for stream and sequential
- packet sockets. See
- <citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details. Defaults to SOMAXCONN (128).</para></listitem>
+ <listitem><para>Takes an unsigned 32bit integer argument. Specifies the number of connections to
+ queue that have not been accepted yet. This setting matters only for stream and sequential packet
+ sockets. See
+ <citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry> for
+ details. Note that this value is silently capped by the <literal>net.core.somaxconn</literal> sysctl,
+ which typically defaults to 4096. By default this is set to 4294967295, so that the sysctl takes full
+ effect.</para></listitem>
</varlistentry>
<varlistentry>
* protocol mismatch. */
int socket_address_parse_unix(SocketAddress *ret_address, const char *s);
int socket_address_parse_vsock(SocketAddress *ret_address, const char *s);
+
+/* libc's SOMAXCONN is defined to 128 or 4096 (at least on glibc). But actually, the value can be much
+ * larger. In our codebase we want to set it to the max usually, since noawadays socket memory is properly
+ * tracked by memcg, and hence we don't need to enforce extra limits here. Moreover, the kernel caps it to
+ * /proc/sys/net/core/somaxconn anyway, thus by setting this to unbounded we just make that sysctl file
+ * authoritative. */
+#define SOMAXCONN_DELUXE INT_MAX
if (r < 0)
return log_error_errno(errno, "Failed to bind private socket: %m");
- r = listen(fd, SOMAXCONN);
+ r = listen(fd, SOMAXCONN_DELUXE);
if (r < 0)
return log_error_errno(errno, "Failed to make private socket listening: %m");
assert(u);
assert(u->load_state == UNIT_STUB);
- s->backlog = SOMAXCONN;
+ s->backlog = SOMAXCONN_DELUXE;
s->timeout_usec = u->manager->default_timeout_start_usec;
s->directory_mode = 0755;
s->socket_mode = 0666;
(void) chmod(sa.un.sun_path, 0666);
- if (listen(s->stdout_fd, SOMAXCONN) < 0)
+ if (listen(s->stdout_fd, SOMAXCONN_DELUXE) < 0)
return log_error_errno(errno, "listen(%s) failed: %m", sa.un.sun_path);
} else
(void) fd_nonblock(s->stdout_fd, true);
assert_se(bind(fd, &u.sa, sa_len) >= 0);
usleep(100 * USEC_PER_MSEC);
- assert_se(listen(fd, SOMAXCONN) >= 0);
+ assert_se(listen(fd, SOMAXCONN_DELUXE) >= 0);
usleep(100 * USEC_PER_MSEC);
assert_se(touch(path) >= 0);
return -errno;
if (type == SOCK_STREAM &&
- listen(fd, SOMAXCONN) < 0)
+ listen(fd, SOMAXCONN_DELUXE) < 0)
return -errno;
r = sd_event_add_io(m->event, event_source, fd, EPOLLIN,
goto fail;
if (type == SOCK_STREAM &&
- listen(fd, SOMAXCONN) < 0) {
+ listen(fd, SOMAXCONN_DELUXE) < 0) {
r = -errno;
goto fail;
}
return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
}
- r = listen(s, SOMAXCONN);
+ r = listen(s, SOMAXCONN_DELUXE);
if (r < 0)
return log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to listen the stream: %m");
return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
}
- r = listen(s, SOMAXCONN);
+ r = listen(s, SOMAXCONN_DELUXE);
if (r < 0)
return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to listen the stream: %m");
a.type = type;
- fd = socket_address_listen(&a, type | flags, SOMAXCONN, SOCKET_ADDRESS_DEFAULT,
+ fd = socket_address_listen(&a, type | flags, SOMAXCONN_DELUXE, SOCKET_ADDRESS_DEFAULT,
NULL, false, false, false, 0755, 0644, NULL);
if (fd < 0 || log_get_max_level() >= log_level) {
_cleanup_free_ char *p = NULL;
return r;
}
- if (listen(fd, SOMAXCONN) < 0)
+ if (listen(fd, SOMAXCONN_DELUXE) < 0)
return -errno;
r = varlink_server_create_listen_fd_socket(s, fd, &ss);
assert_se(flush_accept(listen_dgram) < 0);
assert_se(flush_accept(listen_seqpacket) < 0);
- assert_se(listen(listen_stream, SOMAXCONN) >= 0);
- assert_se(listen(listen_dgram, SOMAXCONN) < 0);
- assert_se(listen(listen_seqpacket, SOMAXCONN) >= 0);
+ assert_se(listen(listen_stream, SOMAXCONN_DELUXE) >= 0);
+ assert_se(listen(listen_dgram, SOMAXCONN_DELUXE) < 0);
+ assert_se(listen(listen_seqpacket, SOMAXCONN_DELUXE) >= 0);
assert_se(flush_accept(listen_stream) >= 0);
assert_se(flush_accept(listen_dgram) < 0);
if (r < 0)
return log_error_errno(r, "Failed to bind io.systemd.Multiplexer: %m");
- if (listen(m->listen_fd, SOMAXCONN) < 0)
+ if (listen(m->listen_fd, SOMAXCONN_DELUXE) < 0)
return log_error_errno(errno, "Failed to listen on socket: %m");
}