Improved latency for traffic initiated from server

CHANGELOG

@@ -5,6 +5,12 @@ iodine - http://code.kryo.se/iodine
 
 CHANGES:
 
+2008-xx-xx: 0.x.x
+	- Delayed sending responses in server to improve latency. Pings from
+		server to client are now always fast instead of cycling from
+		fast to 1000 ms.
+	- The server now replies to all received queries.
+
 2008-08-06: 0.4.2 "Opened Zone"
 	- Applied a few small patches from Maxim Bourmistrov and Gregor Herrmann
 	- Applied a patch for not creating and configuring the tun interface,

src/iodined.c

@@ -107,6 +107,13 @@ tunnel_tun(int tun_fd, int dns_fd)
 	if (users[userid].outpacket.len == 0) {
 		memcpy(users[userid].outpacket.data, out, outlen);
 		users[userid].outpacket.len = outlen;
+		if (users[userid].q.id != 0) {
+			/* If delayed response is kept, send reply immediately */
+			write_dns(dns_fd, &(users[userid].q), users[userid].outpacket.data, users[userid].outpacket.len);
+			users[userid].outpacket.len = 0;
+			users[userid].q.id = 0;
+			return 0;
+		}
 		return outlen;
 	} else {
 		return 0;
@@ -252,6 +259,12 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
 			write_dns(dns_fd, q, "BADIP", 5);
 			return; /* illegal id */
 		}
+		if (users[userid].q.id != 0) {
+			/* If delayed response is kept, send empty reply before overwriting */
+			write_dns(dns_fd, &(users[userid].q), users[userid].outpacket.data, users[userid].outpacket.len);
+			users[userid].outpacket.len = 0;
+			users[userid].q.id = 0;
+		}
 		memcpy(&(users[userid].q), q, sizeof(struct query));
 		users[userid].last_pkt = time(NULL);
 	} else if(in[0] == 'Z' || in[0] == 'z') {
@@ -285,6 +298,12 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q)
 					   users[userid].encoder);
 
 			users[userid].last_pkt = time(NULL);
+			if (users[userid].q.id != 0) {
+				/* If delayed response is kept, send empty reply before overwriting */
+				write_dns(dns_fd, &(users[userid].q), users[userid].outpacket.data, users[userid].outpacket.len);
+				users[userid].outpacket.len = 0;
+				users[userid].q.id = 0;
+			}
 			memcpy(&(users[userid].q), q, sizeof(struct query));
 			memcpy(users[userid].inpacket.data + users[userid].inpacket.offset, unpacked, read);
 			users[userid].inpacket.len += read;
@@ -353,16 +372,10 @@ tunnel(int tun_fd, int dns_fd)
 	struct timeval tv;
 	fd_set fds;
 	int i;
-	int j;
 
 	while (running) {
-		if (users_waiting_on_reply()) {
+		tv.tv_sec = 1;
-			tv.tv_sec = 0;
+		tv.tv_usec = 0;
-			tv.tv_usec = 5000;
-		} else {
-			tv.tv_sec = 1;
-			tv.tv_usec = 0;
-		}
 
 		FD_ZERO(&fds);
 		/* TODO : use some kind of packet queue */
@@ -379,23 +392,13 @@ tunnel(int tun_fd, int dns_fd)
 			return 1;
 		}
 	
-		if (i==0) {	
+		if(FD_ISSET(tun_fd, &fds)) {
-			for (j = 0; j < USERS; j++) {
+			tunnel_tun(tun_fd, dns_fd);
-				if (users[j].q.id != 0) {
+			continue;
-					write_dns(dns_fd, &(users[j].q), users[j].outpacket.data, users[j].outpacket.len);
+		}
-					users[j].outpacket.len = 0;
+		if(FD_ISSET(dns_fd, &fds)) {
-					users[j].q.id = 0;
+			tunnel_dns(tun_fd, dns_fd);
-				}
+			continue;
-			}
-		} else {
-			if(FD_ISSET(tun_fd, &fds)) {
-				tunnel_tun(tun_fd, dns_fd);
-				continue;
-			}
-			if(FD_ISSET(dns_fd, &fds)) {
-				tunnel_dns(tun_fd, dns_fd);
-				continue;
-			} 
 		} 
 	}
 

src/user.c

@@ -53,23 +53,6 @@ init_users(in_addr_t my_ip)
 	}
 }
 
-int
-users_waiting_on_reply()
-{
-	int ret;
-	int i;
-
-	ret = 0;
-	for (i = 0; i < USERS; i++) {
-		if (users[i].active && users[i].last_pkt + 60 > time(NULL) &&
-			users[i].q.id != 0) {
-			ret++;
-		}
-	}
-	
-	return ret;
-}
-
 int
 find_user_by_ip(uint32_t ip)
 {

src/user.h

@@ -35,7 +35,6 @@ struct user {
 extern struct user users[USERS];
 
 void init_users(in_addr_t);
-int users_waiting_on_reply();
 int find_user_by_ip(uint32_t);
 int all_users_waiting_to_send();
 int find_available_user();

tests/user.c

@@ -46,29 +46,6 @@ START_TEST(test_init_users)
 }
 END_TEST
 
-START_TEST(test_users_waiting)
-{
-	in_addr_t ip;
-
-	ip = inet_addr("127.0.0.1");
-	init_users(ip);
-
-	fail_unless(users_waiting_on_reply() == 0);
-
-	users[3].active = 1;
-
-	fail_unless(users_waiting_on_reply() == 0);
-
-	users[3].last_pkt = time(NULL);
-	
-	fail_unless(users_waiting_on_reply() == 0);
-	
-	users[3].q.id = 1;
-	
-	fail_unless(users_waiting_on_reply() == 1);
-}
-END_TEST
-
 START_TEST(test_find_user_by_ip)
 {
 	in_addr_t ip;
@@ -153,7 +130,6 @@ test_user_create_tests()
 
 	tc = tcase_create("User");
 	tcase_add_test(tc, test_init_users);
-	tcase_add_test(tc, test_users_waiting);
 	tcase_add_test(tc, test_find_user_by_ip);
 	tcase_add_test(tc, test_all_users_waiting_to_send);
 	tcase_add_test(tc, test_find_available_user);