diff --git a/include/common.h b/include/common.h
index a9bab28..75f17d6 100644
--- a/include/common.h
+++ b/include/common.h
@@ -1,6 +1,9 @@
 #ifndef COMMON_H_
 #define COMMON_H_
 
+#define TRUE  1
+#define FALSE 0
+
 #define VERSION "1.0.1-beta"
 
 #define RANDOM_PORT_START 41952
diff --git a/src/load.c b/src/load.c
index ab69b24..8578531 100644
--- a/src/load.c
+++ b/src/load.c
@@ -7,18 +7,18 @@
 
 void init_info(bootstrap *info);
 void dump_info(bootstrap *info);
-char** add_extra_opts(char **opts, char *extra_opts_str);
 void json_decode(char *json_content, bootstrap *info);
+char** add_extra_opts(char **opts, char *extra_opts_str);
 int add_field(char *field, char **target, char ***arg, char ***arg_limit);
 
 void init_info(bootstrap *info) {
-    info->is_udp_proxy = 1; // enabled udp proxy
+    info->is_udp_proxy = TRUE; // enabled udp proxy
     info->server_addr = info->client_addr = NULL;
     info->server_port = info->client_port = NULL;
     info->password = NULL;
     info->method = NULL;
     info->timeout = NULL;
-    info->fastopen = 0;
+    info->fastopen = FALSE;
     info->plugin = NULL;
     info->plugin_opts = NULL;
     info->shadowsocks = NULL;
@@ -89,9 +89,9 @@ void json_decode(char *json_content, bootstrap *info) { // decode JSON content
                 log_fatal("`no_udp` must be bool");
             }
             if (json->valueint) { // is_udp_proxy = ~(json->valueint)
-                info->is_udp_proxy = 0;
+                info->is_udp_proxy = FALSE;
             } else {
-                info->is_udp_proxy = 1;
+                info->is_udp_proxy = TRUE;
             }
         } else if (!strcmp(json->string, "server")) { // server => server_addr
             if (!cJSON_IsString(json)) {
@@ -201,8 +201,8 @@ void json_decode(char *json_content, bootstrap *info) { // decode JSON content
 }
 
 int add_field(char *field, char **target, char ***arg, char ***arg_limit) {
-    if (strcmp(**arg, field)) { // field not match
-        return 0;
+    if (strcmp(**arg, field) != 0) { // field not match
+        return FALSE;
     }
     if (++(*arg) == *arg_limit) { // without next argument
         log_fatal("`%s` require a parameter", field);
@@ -211,7 +211,7 @@ int add_field(char *field, char **target, char ***arg, char ***arg_limit) {
         free(*target); // override target field
     }
     *target = new_string(**arg);
-    return 1;
+    return TRUE;
 }
 
 bootstrap* load_info(int argc, char **argv) { // load info from input parameters
@@ -231,9 +231,9 @@ bootstrap* load_info(int argc, char **argv) { // load info from input parameters
         if (!strcmp(*arg, "--debug")) { // skip debug flag
             continue;
         } else if (!strcmp(*arg, "--fast-open")) { // --fast-open => fastopen
-            info->fastopen = 1;
+            info->fastopen = TRUE;
         } else if (!strcmp(*arg, "--no-udp")) { // --no-udp => is_udp_proxy
-            info->is_udp_proxy = 0;
+            info->is_udp_proxy = FALSE;
         } else if (!strcmp(*arg, "-c")) { // -c => CONFIG_JSON
             if (++arg == arg_limit) {
                 log_fatal("Miss json file after `-c` flag");
diff --git a/src/local.c b/src/local.c
index 649ae7c..c6dbe50 100644
--- a/src/local.c
+++ b/src/local.c
@@ -30,6 +30,6 @@ int main(int argc, char *argv[]) {
     init(argc, argv, HELP_MSG);
     log_info("Shadowsocks bootstrap local (%s)", VERSION);
     bootstrap *info = load_info(argc, argv);
-    start_bootstrap(1, load_sip003("sslocal", info));
+    start_bootstrap(TRUE, load_sip003("sslocal", info));
     return 0;
 }
diff --git a/src/server.c b/src/server.c
index 7d21142..e62dc76 100644
--- a/src/server.c
+++ b/src/server.c
@@ -30,6 +30,6 @@ int main(int argc, char *argv[]) {
     init(argc, argv, HELP_MSG);
     log_info("Shadowsocks bootstrap server (%s)", VERSION);
     bootstrap *info = load_info(argc, argv);
-    start_bootstrap(0, load_sip003("ssserver", info));
+    start_bootstrap(FALSE, load_sip003("ssserver", info));
     return 0;
 }
diff --git a/src/utils/network.c b/src/utils/network.c
index 32ae892..10ddc45 100644
--- a/src/utils/network.c
+++ b/src/utils/network.c
@@ -5,6 +5,7 @@
 #include <sys/time.h>
 #include <arpa/inet.h>
 #include "network.h"
+#include "common.h"
 #include "logger.h"
 
 #define TIMEOUT 15
@@ -63,7 +64,7 @@ int check_port_available(unsigned int port, int is_udp, int is_ipv6) { // test a
     ipv4_tcp_addr.sin_port = htons(port);
     ipv4_tcp_addr.sin_addr.s_addr = INADDR_ANY;
     if (bind(ipv4_tcp_sock, (struct sockaddr*)&ipv4_tcp_addr, sizeof(ipv4_tcp_addr)) < 0) {
-        return 0; // false
+        return FALSE;
     }
     close(ipv4_tcp_sock);
 
@@ -74,13 +75,13 @@ int check_port_available(unsigned int port, int is_udp, int is_ipv6) { // test a
         ipv4_udp_addr.sin_port = htons(port);
         ipv4_udp_addr.sin_addr.s_addr = INADDR_ANY;
         if (bind(ipv4_udp_sock, (struct sockaddr*)&ipv4_udp_addr, sizeof(ipv4_udp_addr)) < 0) {
-            return 0; // false
+            return FALSE;
         }
         close(ipv4_udp_sock);
     }
 
     if (!is_ipv6) { // ipv6 ignore
-        return 1; // true
+        return TRUE;
     }
 
     ipv6_tcp_sock = socket(AF_INET6, SOCK_STREAM, 0);
@@ -89,7 +90,7 @@ int check_port_available(unsigned int port, int is_udp, int is_ipv6) { // test a
     ipv6_tcp_addr.sin6_port = htons(port);
     ipv6_tcp_addr.sin6_addr = in6addr_any;
     if (bind(ipv6_tcp_sock, (struct sockaddr*)&ipv6_tcp_addr, sizeof(ipv6_tcp_addr)) < 0) {
-        return 0; // false
+        return FALSE;
     }
     close(ipv6_tcp_sock);
 
@@ -100,19 +101,19 @@ int check_port_available(unsigned int port, int is_udp, int is_ipv6) { // test a
         ipv6_udp_addr.sin6_port = htons(port);
         ipv6_udp_addr.sin6_addr = in6addr_any;
         if (bind(ipv6_udp_sock, (struct sockaddr*)&ipv6_udp_addr, sizeof(ipv6_udp_addr)) < 0) {
-            return 0; // false
+            return FALSE;
         }
         close(ipv6_udp_sock);
     }
 
-    return 1; // true
+    return TRUE;
 }
 
 int get_available_port(unsigned short range_start, unsigned short range_end) { // get a available port
     unsigned short port;
     for (;;) { // wait until a available port in range
         port = get_random_num(range_start, range_end); // get a random port in range
-        if (check_port_available(port, 1, 1)) { // port available
+        if (check_port_available(port, TRUE, TRUE)) { // port available
             return (int)port;
         }
     }
@@ -120,24 +121,24 @@ int get_available_port(unsigned short range_start, unsigned short range_end) { /
 
 int is_ipv4_addr(char *address) { // 判断是否为IPv4地址
     if (inet_addr(address) == -1) {
-        return 0;
+        return FALSE;
     }
-    return 1;
+    return TRUE;
 }
 
 int is_ipv6_addr(char *address) { // 判断是否为IPv6地址
     char buf[sizeof(struct in6_addr)];
     if (inet_pton(AF_INET6, address, buf) <= 0) {
-        return 0;
+        return FALSE;
     }
-    return 1;
+    return TRUE;
 }
 
 int is_ip_addr(char *address) { // 判断是否为IP地址
     if (is_ipv4_addr(address) || is_ipv6_addr(address)) {
-        return 1;
+        return TRUE;
     }
-    return 0;
+    return FALSE;
 }
 
 int create_ipv4_udp_sock(char *address, int port) { // 创建并绑定IPv4 UDP端口
@@ -295,17 +296,17 @@ void proxy(char *server_ip, int server_port, char *listen_ip, int listen_port) {
     struct sockaddr_in6 ipv6_client_addr;
     socklen_t ipv4_client_addr_len = sizeof(ipv4_client_addr);
     socklen_t ipv6_client_addr_len = sizeof(ipv6_client_addr);
-    int bind_error_flag = 0;
+    int bind_error_flag = FALSE;
     int is_listen_ipv6 = is_ipv6_addr(listen_ip); // 判断监听地址是否为IPv6
     if (!is_listen_ipv6) { // IPv4客户端
         ipv4_client_fd = create_ipv4_udp_sock(listen_ip, listen_port); // 监听端口描述符
         if (ipv4_client_fd == -1) { // 端口监听失败
-            bind_error_flag = 1;
+            bind_error_flag = TRUE;
         }
     } else { // IPv6客户端
         ipv6_client_fd = create_ipv6_udp_sock(listen_ip, listen_port); // 监听端口描述符
         if (ipv6_client_fd == -1) { // 端口监听失败
-            bind_error_flag = 1;
+            bind_error_flag = TRUE;
         }
     }
     if (bind_error_flag) { // 端口被占用
@@ -313,7 +314,7 @@ void proxy(char *server_ip, int server_port, char *listen_ip, int listen_port) {
         log_warn("UDP communication of the agent will not work properly");
         return;
     }
-    PROXY_EXIT = 0; // 重置退出标识
+    PROXY_EXIT = FALSE; // 重置退出标识
     log_info("UDP Proxy: %s:%d -> %s:%d", listen_ip, listen_port, server_ip, server_port);
     for (;;) {
         if (!is_listen_ipv6) { // IPv4客户端
diff --git a/src/utils/process.c b/src/utils/process.c
index 33cbaf5..97c1902 100644
--- a/src/utils/process.c
+++ b/src/utils/process.c
@@ -9,6 +9,7 @@
 #include <sys/prctl.h>
 #include "network.h"
 #include "process.h"
+#include "common.h"
 #include "logger.h"
 #include "dns.h"
 
@@ -20,8 +21,8 @@ typedef struct {
 
 char *plugin;
 pid_t ss_pid = 0, plugin_pid = 0;
-int exiting = 0; // sub process exiting
-int exited = 0; // all sub process exited
+int exiting = FALSE; // sub process exiting
+int exited = FALSE; // all sub process exited
 
 void error_exit();
 void normal_exit();
@@ -71,8 +72,8 @@ void kill_sub_process() { // kill child process
     while (exiting) {
         sleep(1); // exit process already working -> block
     }
-    exiting = 1; // exit process flag
-    PROXY_EXIT = 1; // udp proxy cancel
+    exiting = TRUE; // exit process flag
+    PROXY_EXIT = TRUE; // udp proxy cancel
     if (ss_pid != 0) {
         kill(ss_pid, SIGKILL);
         log_info("Kill shadowsocks process");
@@ -116,7 +117,7 @@ void get_sub_exit() { // catch child process die
             error_exit();
         }
     }
-    exited = 1;
+    exited = TRUE;
 }
 
 char** load_plugin_env(sip003 *service) { // load plugin's environment variable