add dns & resolve doc

Author: FH0

doc/configuration.md

@@ -8,6 +8,11 @@
 - Support `tcp_nodelay` and `tcp_keepalive_interval`
 - Can only be processed once by `route`.
 
+### resolve
+
+- `resolve` is a special `out`, which is used to resolve domain
+- can be routed
+
 ### out
 
 - Can be processed multiple times by `route`.
@@ -29,6 +34,17 @@
     "uid": 0, // invalid by default, only support linux
     "gid": 1110 // invalid by default, only support linux
   },
+  "resolve": {
+    "tag": "resolve", // default resolve
+    "server": ["8.8.8.8:53", "8.8.4.4", "system"], // default system, send to all servers at the same time, adopt the first reply,  only support android, linux and windows
+    "refresh_system": 3, // valid if server contains system, default 3
+    "udp_timeout": 5, // default 5
+    "cache_size": 1024, // default 1024
+    "refresh_cache": false, // default false
+    "min_ttl": 60, // default 60
+    "max_ttl": 2147483647, // default 2147483647
+    "ipv6_first": false // default false
+  },
   "in": [
     {
       "tag": "socks5_client",
@@ -78,6 +94,17 @@
       "protocol": "http",
       "address": "1.2.3.4:10802",
       "tcp_timeout": 300
+    },
+    {
+      "tag": "dns",
+      "protocol": "dns",
+      "server": ["8.8.8.8:53", "8.8.4.4", "system"], // default system, send to all servers at the same time, adopt the first reply,  only support android, linux and windows
+      "refresh_system": 3, // valid if server contains system, default 3
+      "udp_timeout": 5, // default 5
+      "cache_size": 1024, // default 1024
+      "refresh_cache": false, // default false
+      "min_ttl": 60, // default 60
+      "max_ttl": 2147483647 // default 2147483647
     }
   ],
   "route": [
@@ -95,6 +122,7 @@
       "sport": [],
       "daddr": [],
       "dport": [],
+      "dns_domain": [], // same as addr, only support udp dns packet
       "jump": ""
     }
   ]