From 044536aef6187b347f27ee79378f31d384a96ee6 Mon Sep 17 00:00:00 2001
From: Nick Peng <pymumu@gmail.com>
Date: Sun, 3 Nov 2019 09:15:24 +0800
Subject: [PATCH] optimize tcp connection lag

---
 src/dns_client.c |  6 ++++++
 src/util.c       | 15 +++++++++++++++
 src/util.h       |  2 ++
 3 files changed, 23 insertions(+)

diff --git a/src/dns_client.c b/src/dns_client.c
index 48087a8..30b9529 100644
--- a/src/dns_client.c
+++ b/src/dns_client.c
@@ -1380,6 +1380,9 @@ static int _DNS_client_create_socket_tcp(struct dns_server_info *server_info)
 	setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &yes, sizeof(yes));
 	setsockopt(fd, SOL_SOCKET, SO_PRIORITY, &priority, sizeof(priority));
 	setsockopt(fd, IPPROTO_IP, IP_TOS, &ip_tos, sizeof(ip_tos));
+	setsockopt(fd, IPPROTO_TCP, TCP_THIN_DUPACK, &yes, sizeof(yes));
+	setsockopt(fd, IPPROTO_TCP, TCP_THIN_LINEAR_TIMEOUTS, &yes, sizeof(yes));
+	set_sock_keepalive(fd, 15, 3, 4);
 
 	if (connect(fd, (struct sockaddr *)&server_info->addr, server_info->ai_addrlen) != 0) {
 		if (errno != EINPROGRESS) {
@@ -1449,6 +1452,9 @@ static int _DNS_client_create_socket_tls(struct dns_server_info *server_info, ch
 	// setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &yes, sizeof(yes));
 	setsockopt(fd, SOL_SOCKET, SO_PRIORITY, &priority, sizeof(priority));
 	setsockopt(fd, IPPROTO_IP, IP_TOS, &ip_tos, sizeof(ip_tos));
+	setsockopt(fd, IPPROTO_TCP, TCP_THIN_DUPACK, &yes, sizeof(yes));
+	setsockopt(fd, IPPROTO_TCP, TCP_THIN_LINEAR_TIMEOUTS, &yes, sizeof(yes));
+	set_sock_keepalive(fd, 15, 3, 4);
 
 	if (connect(fd, (struct sockaddr *)&server_info->addr, server_info->ai_addrlen) != 0) {
 		if (errno != EINPROGRESS) {
diff --git a/src/util.c b/src/util.c
index 2a2b695..508900d 100644
--- a/src/util.c
+++ b/src/util.c
@@ -11,6 +11,7 @@
 #include <openssl/crypto.h>
 #include <openssl/ssl.h>
 #include <pthread.h>
+#include <netinet/tcp.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
@@ -933,3 +934,17 @@ int has_network_raw_cap(void)
 	close(fd);
 	return 1;
 }
+
+int set_sock_keepalive(int fd, int keepidle, int keepinterval, int keepcnt)
+{
+	const int yes = 1;
+	if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &yes, sizeof(yes))!= 0) {
+		return -1;
+	}
+
+	setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &keepidle, sizeof(keepidle));
+	setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &keepinterval, sizeof(keepinterval));
+	setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &keepcnt, sizeof(keepcnt));
+
+	return 0;
+}
\ No newline at end of file
diff --git a/src/util.h b/src/util.h
index d438c02..f2b7c09 100644
--- a/src/util.h
+++ b/src/util.h
@@ -69,6 +69,8 @@ void get_compiled_time(struct tm *tm);
 
 int has_network_raw_cap(void);
 
+int set_sock_keepalive(int fd, int keepidle, int keepinterval, int keepcnt);
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus */