[PATCH] use TCP_DEFER_ACCEPT on Linux

[Brian Akins]

I basically copied the way the FreeBSD filters are used.  This does a 
setsockopt to turn on TCP_DEFER_ACCEPT on 2.4 linux kernels.  In Order for 
everything to compile correctly, use "-DTCP_DEFER_ACCEPT" in your CFLAGS.



-- 
Brian Akins
Systems Engineer III
CNN Internet Technologies
diff -pru ./src/include/http_conf_globals.h ../apache_1.3.22-defer/src/include/http_conf_globals.h
--- ./src/include/http_conf_globals.h	Fri Jul 13 03:32:35 2001
+++ ../apache_1.3.22-defer/src/include/http_conf_globals.h	Tue Jan 15 08:31:44 2002
@@ -93,6 +93,10 @@ extern int ap_listenbacklog;
 #ifdef SO_ACCEPTFILTER
 extern int ap_acceptfilter;
 #endif
+#ifdef TCP_DEFER_ACCEPT
+extern int ap_deferaccept;
+extern int ap_deferaccept_timeout;
+#endif
 extern int ap_dump_settings;
 extern API_VAR_EXPORT int ap_extended_status;
 
diff -pru ./src/main/http_core.c ../apache_1.3.22-defer/src/main/http_core.c
--- ./src/main/http_core.c	Tue Sep  4 14:15:15 2001
+++ ../apache_1.3.22-defer/src/main/http_core.c	Tue Jan 15 09:45:22 2002
@@ -2540,6 +2540,22 @@ static const char *set_acceptfilter(cmd_
     return NULL;
 }
 
+/*Use the TCP_DEFER_ACCEPT socket option on Linux*/
+static const char *set_deferaccept(cmd_parms *cmd, void *dummy, int flag)
+{
+#ifdef TCP_DEFER_ACCEPT
+    ap_deferaccept = flag;
+#endif
+    return NULL;
+}
+static const char *set_deferaccept_timeout(cmd_parms *cmd, void *dummy, char *timeout)
+{
+#ifdef TCP_DEFER_ACCEPT
+    ap_deferaccept_timeout = atoi(timeout);
+#endif
+    return NULL;
+}
+
 static const char *set_listener(cmd_parms *cmd, void *dummy, char *ips)
 {
     listen_rec *new;
@@ -3191,6 +3207,26 @@ static const command_rec core_cmds[] = {
 	"is ignored."
 #endif
    },
+{ "DeferAccept", set_deferaccept, NULL, RSRC_CONF, FLAG,
+  "Switch DeferAccept on/off (default is "
+#ifdef AP_DEFERACCEPT_OFF
+	"off"
+#else
+	"on"
+#endif
+	")."
+#ifndef TCP_DEFER_ACCEPT
+	"This feature is currently not compiled in; so this directive "
+	"is ignored."
+#endif
+   },
+{ "DeferAcceptTimeout", set_deferaccept_timeout, NULL, RSRC_CONF, TAKE1,
+  "Set DeferAccept timeout (default is 30"
+#ifndef TCP_DEFER_ACCEPT
+	"This feature is currently not compiled in; so this directive "
+	"is ignored."
+#endif
+	},
 { "CoreDumpDirectory", set_coredumpdir, NULL, RSRC_CONF, TAKE1,
   "The location of the directory Apache changes to before dumping core" },
 { "Include", include_config, NULL, (RSRC_CONF | ACCESS_CONF), TAKE1,
diff -pru ./src/main/http_main.c ../apache_1.3.22-defer/src/main/http_main.c
--- ./src/main/http_main.c	Fri Oct  5 22:21:11 2001
+++ ../apache_1.3.22-defer/src/main/http_main.c	Tue Jan 15 09:50:05 2002
@@ -272,12 +272,23 @@ accept_mutex_methods_s *amutex;
 #ifdef SO_ACCEPTFILTER
 int ap_acceptfilter =
 #ifdef AP_ACCEPTFILTER_OFF
-	0;
+    0;
 #else
 	1;
 #endif
 #endif
 
+#ifdef TCP_DEFER_ACCEPT
+int ap_deferaccept_timeout = 30;
+int ap_deferaccept =
+#ifdef AP_DEFERACCEPT_OFF
+    0;
+#else
+	1;
+#endif
+#endif
+
+
 int ap_dump_settings = 0;
 API_VAR_EXPORT int ap_extended_status = 0;
 
@@ -3679,6 +3690,21 @@ static int make_sock(pool *p, const stru
     }
 #endif
 
+#ifdef TCP_DEFER_ACCEPT
+	if (ap_deferaccept) {
+		
+		if (setsockopt(s, SOL_TCP, TCP_DEFER_ACCEPT, &ap_deferaccept_timeout, sizeof(int)) < 0) {
+            if (errno == ENOPROTOOPT) {
+				ap_log_error(APLOG_MARK, APLOG_INFO | APLOG_NOERRNO, server_conf,
+							 "socket option TCP_DEFER_ACCEPT unkown on this machine. Continuing.");
+			} else {
+				ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_NOERRNO, server_conf,
+							 "make_sock: for %s, setsockopt: (TCP_DEFER_ACCEPT) failed", addr);
+			}
+		} 
+	}
+#endif
+
 #ifdef WORKAROUND_SOLARIS_BUG
     s = ap_slack(s, AP_SLACK_HIGH);
 
@@ -3987,6 +4013,12 @@ static void show_compile_settings(void)
 #endif
 #ifdef AP_ACCEPTFILTER_OFF
     printf(" -D AP_ACCEPTFILTER_OFF\n");
+#endif
+#ifdef TCP_DEFER_ACCEPT
+    printf(" -D DEFER_ACCEPT\n");
+#endif
+#ifdef AP_DEFERACCEPT_OFF
+    printf(" -D AP_DEFERACCEPT_OFF\n");
 #endif