diff --git a/examples/socket/ping.lua b/examples/socket/ping.lua
index d27a155..1a13823 100755
--- a/examples/socket/ping.lua
+++ b/examples/socket/ping.lua
@@ -9,8 +9,6 @@ local socket = require 'eco.socket'
 local time = require 'eco.time'
 
 local ICMP_HEADER_LEN = 8
-local ICMP_ECHO = 8
-local ICMP_ECHOREPLY = 0
 
 local dest_ip = '127.0.0.1'
 local local_id = math.random(0, 65535)
@@ -19,7 +17,7 @@ local local_data = 'hello'
 
 local function build_icmp_req()
     local data = {
-        string.char(ICMP_ECHO), -- type
+        string.char(socket.ICMP_ECHO), -- type
         '\0',        -- code
         '\0\0',      -- checksum
         '\0\0',      -- id: the kernel will assign it with local port
@@ -81,7 +79,7 @@ while true do
     local icmp_type, id, seq, n = parse_icmp_resp(resp)
 
     if icmp_type then
-        if icmp_type == ICMP_ECHOREPLY then
+        if icmp_type == socket.ICMP_ECHOREPLY then
             if id == local_id then
                 print(string.format('%d bytes from %s: icmp_seq=%d time=%.3f ms', n, dest_ip, seq, elapsed * 1000))
             end
diff --git a/examples/socket/ping6.lua b/examples/socket/ping6.lua
index f9a324c..275f124 100755
--- a/examples/socket/ping6.lua
+++ b/examples/socket/ping6.lua
@@ -9,8 +9,6 @@ local socket = require 'eco.socket'
 local time = require 'eco.time'
 
 local ICMP6_HEADER_LEN = 8
-local ICMP6_ECHO = 128
-local ICMP6_ECHOREPLY = 129
 
 local dest_ip = '::1'
 local local_id = math.random(0, 65535)
@@ -19,7 +17,7 @@ local local_data = 'hello'
 
 local function build_icmp_req()
     local data = {
-        string.char(ICMP6_ECHO), -- type
+        string.char(socket.ICMPV6_ECHO_REQUEST), -- type
         '\0',        -- code
         '\0\0',      -- checksum
         '\0\0',      -- id: the kernel will assign it with local port
@@ -81,7 +79,7 @@ while true do
     local icmp_type, id, seq, n = parse_icmp_resp(resp)
 
     if icmp_type then
-        if icmp_type == ICMP6_ECHOREPLY then
+        if icmp_type == socket.ICMPV6_ECHO_REPLY then
             if id == local_id then
                 print(string.format('%d bytes from %s: icmp_seq=%d time=%.3f ms', n, dest_ip, seq, elapsed * 1000))
             end
diff --git a/socket.c b/socket.c
index 8b7e32e..c2b03d0 100644
--- a/socket.c
+++ b/socket.c
@@ -19,6 +19,8 @@
 #include <linux/if_ether.h>
 #include <linux/if_arp.h>
 #include <netinet/tcp.h>
+#include <linux/icmpv6.h>
+#include <linux/icmp.h>
 
 #include "eco.h"
 
@@ -1125,5 +1127,11 @@ int luaopen_eco_core_socket(lua_State *L)
 
     lua_add_constant(L, "PACKET_MR_PROMISC", PACKET_MR_PROMISC);
 
+    lua_add_constant(L, "ICMP_ECHOREPLY", ICMP_ECHOREPLY);
+    lua_add_constant(L, "ICMP_ECHO", ICMP_ECHO);
+
+    lua_add_constant(L, "ICMPV6_ECHO_REQUEST", ICMPV6_ECHO_REQUEST);
+    lua_add_constant(L, "ICMPV6_ECHO_REPLY", ICMPV6_ECHO_REPLY);
+
     return 1;
 }