Add defer_accept option to enable TCP_DEFER_ACCEPT

Merge: 6fb5e9636fa1fffc62e86561e7dcd734fa2ee53f

Add defer_accept option to enable TCP_DEFER_ACCEPT
Charybdis commits referenced:

atheme/charybdis@77cb59b
    libratbox: add support for TCP_DEFER_ACCEPT on linux

atheme/charybdis@aa4737a
    libratbox: make defer_accept optional.

atheme/charybdis@02270e9
    Add listen::defer_accept option for controlling usage
    of TCP_DEFER_ACCEPT option.

atheme/charybdis@797a29f
    libratbox: Allow defer_accept on FreeBSD.

doc/example.conf

@@ -136,6 +136,13 @@ class "server" {
 };
 
 listen {
+	/* defer_accept: wait for clients to send IRC handshake data before
+	 * accepting them.  if you intend to use software which depends on the
+	 * server replying first, such as BOPM, you should disable this feature.
+	 * otherwise, you probably want to leave it on.
+	 */
+	defer_accept = yes;
+
 	/* If you want to listen on a specific IP only, specify host.
 	 * host definitions apply only to the following port line.
 	 */

doc/reference.conf

@@ -304,6 +304,13 @@ class "server" {
 
 /* listen {}: contain information about the ports ircd listens on (OLD P:) */
 listen {
+	/* defer_accept: wait for clients to send IRC handshake data before
+	 * accepting them.  if you intend to use software which depends on the
+	 * server replying first, such as BOPM, you should disable this feature.
+	 * otherwise, you probably want to leave it on.
+	 */
+	defer_accept = yes;
+
 	/* port: the specific port to listen on.  if no host is specified
 	 * before, it will listen on all available IPs.
 	 *

include/listener.h

@@ -38,12 +38,13 @@ struct Listener
 	int ref_count;		/* number of connection references */
 	int active;		/* current state of listener */
 	int ssl;		/* ssl listener */
+	int defer_accept;       /* use TCP_DEFER_ACCEPT */
 	struct rb_sockaddr_storage addr;
 	struct DNSQuery *dns_query;
 	char vhost[HOSTLEN + 1];	/* virtual name of listener */
 };
 
-extern void add_listener(int port, const char *vaddr_ip, int family, int ssl);
+extern void add_listener(int port, const char *vaddr_ip, int family, int ssl, int defer_accept);
 extern void close_listener(struct Listener *listener);
 extern void close_listeners(void);
 extern const char *get_listener_name(const struct Listener *listener);

libratbox/configure

@@ -12838,7 +12838,7 @@ $as_echo "#define STDC_HEADERS 1" >>confdefs.h
 fi
 
 
-for ac_header in crypt.h unistd.h sys/socket.h sys/stat.h sys/time.h time.h netinet/in.h arpa/inet.h errno.h sys/uio.h spawn.h sys/poll.h sys/epoll.h sys/select.h sys/devpoll.h sys/event.h port.h signal.h sys/signalfd.h sys/timerfd.h
+for ac_header in crypt.h unistd.h sys/socket.h sys/stat.h sys/time.h time.h netinet/in.h arpa/inet.h errno.h sys/uio.h spawn.h sys/poll.h sys/epoll.h sys/select.h sys/devpoll.h sys/event.h port.h signal.h sys/signalfd.h sys/timerfd.h linux/tcp.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"

libratbox/configure.ac

@@ -105,7 +105,7 @@ AC_TYPE_UID_T
 dnl Checks for header files.
 AC_HEADER_STDC
 
-AC_CHECK_HEADERS([crypt.h unistd.h sys/socket.h sys/stat.h sys/time.h time.h netinet/in.h arpa/inet.h errno.h sys/uio.h spawn.h sys/poll.h sys/epoll.h sys/select.h sys/devpoll.h sys/event.h port.h signal.h sys/signalfd.h sys/timerfd.h])
+AC_CHECK_HEADERS([crypt.h unistd.h sys/socket.h sys/stat.h sys/time.h time.h netinet/in.h arpa/inet.h errno.h sys/uio.h spawn.h sys/poll.h sys/epoll.h sys/select.h sys/devpoll.h sys/event.h port.h signal.h sys/signalfd.h sys/timerfd.h linux/tcp.h])
 AC_HEADER_TIME
 
 dnl Networking Functions

libratbox/include/commio-ssl.h

@@ -27,7 +27,7 @@
 int rb_setup_ssl_server(const char *cert, const char *keyfile, const char *dhfile);
 int rb_init_ssl(void);
 
-int rb_ssl_listen(rb_fde_t *F, int backlog);
+int rb_ssl_listen(rb_fde_t *F, int backlog, int defer_accept);
 int rb_init_prng(const char *path, prng_seed_t seed_type);
 
 int rb_get_random(void *buf, size_t length);

libratbox/include/libratbox_config.h.in

@@ -60,15 +60,15 @@
 /* Define to 1 if you have the `gmtime_r' function. */
 #undef HAVE_GMTIME_R
 
-/* Has GnuTLS */
-#undef HAVE_GNUTLS
-
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
 /* Define to 1 if you have the `kevent' function. */
 #undef HAVE_KEVENT
 
+/* Define to 1 if you have the <linux/tcp.h> header file. */
+#undef HAVE_LINUX_TCP_H
+
 /* Define to 1 if you have the <memory.h> header file. */
 #undef HAVE_MEMORY_H
 

libratbox/include/ratbox_lib.h

@@ -13,6 +13,10 @@
 #include <signal.h>
 #include <ctype.h>
 
+#ifdef HAVE_LINUX_TCP_H
+# include <linux/tcp.h>
+#endif
+
 #ifdef __GNUC__
 #undef alloca
 #define alloca __builtin_alloca

libratbox/include/rb_commio.h

@@ -125,8 +125,8 @@ ssize_t rb_read(rb_fde_t *, void *buf, int count);
 int rb_pipe(rb_fde_t **, rb_fde_t **, const char *desc);
 
 int rb_setup_ssl_server(const char *cert, const char *keyfile, const char *dhfile);
-int rb_ssl_listen(rb_fde_t *, int backlog);
+int rb_ssl_listen(rb_fde_t *, int backlog, int defer_accept);
-int rb_listen(rb_fde_t *, int backlog);
+int rb_listen(rb_fde_t *, int backlog, int defer_accept);
 
 const char *rb_inet_ntop(int af, const void *src, char *dst, unsigned int size);
 int rb_inet_pton(int af, const char *src, void *dst);

libratbox/src/commio.c

@@ -760,11 +760,33 @@ mangle_mapped_sockaddr(struct sockaddr *in)
  * rb_listen() - listen on a port
  */
 int
-rb_listen(rb_fde_t *F, int backlog)
+rb_listen(rb_fde_t *F, int backlog, int defer_accept)
 {
+	int result;
+
 	F->type = RB_FD_SOCKET | RB_FD_LISTEN;
-	/* Currently just a simple wrapper for the sake of being complete */
+
-	return listen(F->fd, backlog);
+	result = listen(F->fd, backlog);
+
+#ifdef TCP_DEFER_ACCEPT
+	if (defer_accept && !result)
+	{
+		setsockopt(F->fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &backlog, sizeof(int));
+	}
+#endif
+#ifdef SO_ACCEPTFILTER
+	if (defer_accept && !result)
+	{
+		struct accept_filter_arg afa;
+
+		memset(&afa, '\0', sizeof afa);
+		rb_strlcpy(afa.af_name, "dataready", sizeof afa.af_name);
+		(void)setsockopt(F->fd, SOL_SOCKET, SO_ACCEPTFILTER, &afa,
+		                sizeof afa);
+	}
+#endif
+
+	return result;
 }
 
 void

libratbox/src/gnutls.c

@@ -347,10 +347,14 @@ rb_setup_ssl_server(const char *cert, const char *keyfile, const char *dhfile)
 }
 
 int
-rb_ssl_listen(rb_fde_t *F, int backlog)
+rb_ssl_listen(rb_fde_t *F, int backlog, int defer_accept)
 {
+	int result;
+
+	result = listen(F->fd, backlog, defer_accept);
 	F->type = RB_FD_SOCKET | RB_FD_LISTEN | RB_FD_SSL;
-	return listen(F->fd, backlog);
+
+	return result;
 }
 
 struct ssl_connect

libratbox/src/nossl.c

@@ -48,7 +48,7 @@ rb_init_ssl(void)
 }
 
 int
-rb_ssl_listen(rb_fde_t *F, int backlog)
+rb_ssl_listen(rb_fde_t *F, int backlog, int defer_accept)
 {
 	errno = ENOSYS;
 	return -1;

libratbox/src/openssl.c

@@ -389,10 +389,14 @@ rb_setup_ssl_server(const char *cert, const char *keyfile, const char *dhfile)
 }
 
 int
-rb_ssl_listen(rb_fde_t *F, int backlog)
+rb_ssl_listen(rb_fde_t *F, int backlog, int defer_accept)
 {
+	int result;
+
+	result = rb_listen(F, backlog, defer_accept);
 	F->type = RB_FD_SOCKET | RB_FD_LISTEN | RB_FD_SSL;
-	return listen(F->fd, backlog);
+
+	return result;
 }
 
 struct ssl_connect

src/listener.c

@@ -230,7 +230,7 @@ inetport(struct Listener *listener)
 		return 0;
 	}
 
-	if(rb_listen(F, RATBOX_SOMAXCONN))
+	if(rb_listen(F, RATBOX_SOMAXCONN, listener->defer_accept))
 	{
 		ilog_error("listen()");
 		rb_close(F);
@@ -303,7 +303,7 @@ find_listener(struct rb_sockaddr_storage *addr)
  * the format "255.255.255.255"
  */
 void
-add_listener(int port, const char *vhost_ip, int family, int ssl)
+add_listener(int port, const char *vhost_ip, int family, int ssl, int defer_accept)
 {
 	struct Listener *listener;
 	struct rb_sockaddr_storage vaddr;
@@ -376,6 +376,7 @@ add_listener(int port, const char *vhost_ip, int family, int ssl)
 
 	listener->F = NULL;
 	listener->ssl = ssl;
+	listener->defer_accept = defer_accept;
 
 	if(inetport(listener))
 		listener->active = 1;

src/newconf.c

@@ -31,6 +31,8 @@
 
 #define CF_TYPE(x) ((x) & CF_MTYPE)
 
+static int yy_defer_accept = 1;
+
 struct TopConf *conf_cur_block;
 static char *conf_cur_block_name;
 
@@ -871,7 +873,11 @@ conf_end_listen(struct TopConf *tc)
 	return 0;
 }
 
-
+static void
+conf_set_listen_defer_accept(void *data)
+{
+	yy_defer_accept = *(unsigned int *) data;
+}
 
 static void
 conf_set_listen_port_both(void *data, int ssl)
@@ -887,9 +893,9 @@ conf_set_listen_port_both(void *data, int ssl)
 		}
                 if(listener_address == NULL)
                 {
-			add_listener(args->v.number, listener_address, AF_INET, ssl);
+			add_listener(args->v.number, listener_address, AF_INET, ssl, yy_defer_accept);
 #ifdef RB_IPV6
-			add_listener(args->v.number, listener_address, AF_INET6, ssl);
+			add_listener(args->v.number, listener_address, AF_INET6, ssl, yy_defer_accept);
 #endif
                 }
 		else
@@ -902,7 +908,7 @@ conf_set_listen_port_both(void *data, int ssl)
 #endif
 				family = AF_INET;
 		
-			add_listener(args->v.number, listener_address, family, ssl);
+			add_listener(args->v.number, listener_address, family, ssl, yy_defer_accept);
                 
                 }
 
@@ -2343,6 +2349,7 @@ newconf_init()
 	add_top_conf("privset", NULL, NULL, conf_privset_table);
 
 	add_top_conf("listen", conf_begin_listen, conf_end_listen, NULL);
+	add_conf_item("listen", "defer_accept", CF_YESNO, conf_set_listen_defer_accept);
 	add_conf_item("listen", "port", CF_INT | CF_FLIST, conf_set_listen_port);
 	add_conf_item("listen", "sslport", CF_INT | CF_FLIST, conf_set_listen_sslport);
 	add_conf_item("listen", "ip", CF_QSTRING, conf_set_listen_address);