net_info module - ping function

app/include/user_config.h

@@ -136,6 +136,9 @@
 //#define TIMER_SUSPEND_ENABLE
 //#define PMSLEEP_ENABLE
 
+// The net module optionally offers net info functionnality. Uncomment the following
+// to enable the functionnality.
+#define NET_PING_ENABLE 
 
 // The WiFi module optionally offers an enhanced level of WiFi connection
 // management, using internal timer callbacks.  Whilst many Lua developers

app/modules/net.c

@@ -20,6 +20,8 @@
 #include "lwip/udp.h"
 #include "lwip/dhcp.h"
 
+#include "net_ping.h"
+
 typedef enum net_type {
   TYPE_TCP_SERVER = 0,
   TYPE_TCP_CLIENT,
@@ -1070,6 +1072,9 @@ LROT_BEGIN(net, NULL, 0)
   LROT_FUNCENTRY( ifinfo, net_ifinfo )
   LROT_FUNCENTRY( multicastJoin, net_multicastJoin )
   LROT_FUNCENTRY( multicastLeave, net_multicastLeave )
+#ifdef NET_PING_ENABLE
+  LROT_FUNCENTRY( ping, net_ping )
+#endif
   LROT_TABENTRY( dns, net_dns_map )
 #ifdef TLS_MODULE_PRESENT
   LROT_TABENTRY( cert, tls_cert )

app/modules/net_ping.c

@@ -0,0 +1,155 @@
+// ***************************************************************************
+// net_ping functionnality for ESP8266 with nodeMCU
+//
+// Written by Lukas Voborsky (@voborsky) with great help by TerryE
+// ***************************************************************************
+
+// #define NODE_DEBUG
+
+#include "net_ping.h"
+
+#include "module.h"
+#include "lauxlib.h"
+
+#include "lwip/ip_addr.h"
+#include "espconn.h"
+#include "lwip/dns.h" 
+#include "lwip/app/ping.h"
+
+/* 
+ping_opt needs to be the first element of the structure. It is a workaround to pass the 
+callback reference and self_ref to the ping_received function. Pointer the ping_option 
+structure is equal to the pointer to net_ping_t structure.
+*/
+typedef struct {
+  struct ping_option ping_opt; 
+  uint32_t ping_callback_ref; 
+ } net_ping_t;
+typedef net_ping_t* ping_t;  
+
+/*
+ *  ping_received_sent(pingresp)
+*/
+#define LuaCBreceivedfunc  lua_upvalueindex(1)
+#define LuaCBsentfunc  lua_upvalueindex(2)
+#define nipUD      lua_upvalueindex(3)
+
+static int ping_received_sent(lua_State *L) {
+    struct ping_resp *resp = (struct ping_resp *) lua_touserdata (L, 1);
+    ping_t nip  = (ping_t) lua_touserdata (L, nipUD);
+
+    NODE_DBG("[net_info ping_received_sent] nip = %p\n", nip);
+
+    if (resp == NULL) {  /* resolution failed so call the CB with 0 byte count to flag this */
+        luaL_unref(L, LUA_REGISTRYINDEX, nip->ping_callback_ref);
+        lua_pushvalue(L, LuaCBreceivedfunc);
+        lua_pushinteger(L, 0);
+        luaL_pcallx(L, 1, 0);
+        return 0;
+    }
+    char ipaddrstr[16];
+    ipaddr_ntoa_r((ip_addr_t *) &nip->ping_opt.ip, ipaddrstr, sizeof(ipaddrstr));
+
+    if (resp->total_count == 0) { /* processing receive response */
+        NODE_DBG("[ping_received] %s: resp_time=%d seqno=%d bytes=%d ping_err=%d\n",
+                 ipaddrstr, resp->resp_time, resp->seqno, resp->bytes, resp->ping_err);
+        lua_pushvalue(L, LuaCBreceivedfunc);
+        lua_pushinteger(L, resp->bytes);
+        lua_pushstring(L, ipaddrstr);
+        lua_pushinteger(L, resp->seqno);
+        lua_pushinteger(L, resp->ping_err == 0 ? resp->resp_time: -1);        
+        luaL_pcallx(L, 4, 0);
+    } else { /* processing sent response */
+        NODE_DBG("[ping_sent] %s: total_count=%d timeout_count=%d "
+                 "total_bytes=%d total_time=%d\n",
+                 ipaddrstr, resp->total_count, resp->timeout_count, 
+                 resp->total_bytes, resp->total_time);
+
+        lua_pushvalue(L, LuaCBsentfunc);
+        if lua_isfunction(L, -1) {
+          lua_pushstring(L, ipaddrstr);
+          lua_pushinteger(L, resp->total_count);
+          lua_pushinteger(L, resp->timeout_count);
+          lua_pushinteger(L, resp->total_bytes);
+          lua_pushinteger(L, resp->total_time);        
+          luaL_pcallx(L, 5, 0);
+        }
+        luaL_unref(L, LUA_REGISTRYINDEX, nip->ping_callback_ref); /* unregister the closure */
+    }
+    return 0;
+}
+
+
+/*
+ *  Wrapper to call ping_received_sent(pingresp)
+ */
+static void ping_CB(net_ping_t *nip, struct ping_resp *pingresp) {
+    NODE_DBG("[net_info ping_CB] nip = %p, nip->ping_callback_ref = %p, pingresp= %p\n", nip, nip->ping_callback_ref, pingresp);
+    lua_State *L = lua_getstate();
+    lua_rawgeti(L, LUA_REGISTRYINDEX, nip->ping_callback_ref);
+    lua_pushlightuserdata(L, pingresp);   
+    lua_call(L, 1, 0); // call the closure (ping_received_sent)
+}
+
+/*
+ *  Wrapper to call ping_start using fully resolve IP4 address
+ */
+static void net_ping_raw(const char *name, ip_addr_t *ipaddr, ping_t nip) {
+    NODE_DBG("[net_ping_raw] name = %s, ipaddr= %x\n", name, ipaddr);
+    if (ipaddr) {
+      char ipaddrstr[16];
+      ipaddr_ntoa_r(ipaddr, ipaddrstr, sizeof(ipaddrstr));
+      NODE_DBG("[net_ping_raw] ip: %s\n", ipaddrstr);
+    }    
+    lua_State *L = lua_getstate();
+
+    if (!ipaddr || ipaddr->addr == 0xFFFFFFFF) {
+        ping_CB(nip, NULL);  /* A NULL pinresp flags DNS resolution failure */
+        return;
+    }
+
+    nip->ping_opt.ip = ipaddr->addr;     
+    NODE_DBG("[net_ping_raw] calling ping_start\n");
+    if (!ping_start(&(nip->ping_opt))) {
+        luaL_unref(L, LUA_REGISTRYINDEX, nip->ping_callback_ref);
+        luaL_error(L, "memory allocation error: cannot start ping");
+    }
+}
+
+// Lua:  net.ping(domain, [count], callback)
+int net_ping(lua_State *L)
+{
+    ip_addr_t addr;
+
+    // retrieve function parameters
+    const char *ping_target = luaL_checkstring(L, 1);
+    bool isf2 = lua_isfunction(L, 2);
+    lua_Integer l_count  = isf2 ? 0: luaL_optinteger(L, 2, 0);  /* use ping_start() default */
+    lua_settop(L, isf2 ? 3 : 4);
+    luaL_argcheck(L, lua_isfunction(L, -2), -2, "no received callback specified");
+    luaL_argcheck(L, lua_isfunction(L, -1) || lua_isnil(L, -1), -1, "invalid sent callback, function expected");
+
+    ping_t nip = (ping_t) memset(lua_newuserdata(L, sizeof(*nip)), 0, sizeof(*nip));
+
+    /* Register C closure with 3 Upvals: (1) Lua CB receive function; (2) Lua CB sent function; (3) nip Userdata */ 
+    lua_pushcclosure(L, ping_received_sent, 3); // stack has 2 callbacks and nip UD; [-3, +1, m]
+
+    nip->ping_callback_ref = luaL_ref(L, LUA_REGISTRYINDEX); // registers the closure to registry [-1, +0, m]
+    nip->ping_opt.count = l_count;
+    nip->ping_opt.coarse_time = 0;
+    nip->ping_opt.recv_function = (ping_recv_function) &ping_CB;
+    nip->ping_opt.sent_function = (ping_sent_function) &ping_CB;
+
+    NODE_DBG("[net_ping] nip = %p, nip->ping_callback_ref = %p\n", nip, nip->ping_callback_ref);
+
+    err_t err = dns_gethostbyname(ping_target, &addr, (dns_found_callback) net_ping_raw, nip);
+    if (err != ERR_OK && err != ERR_INPROGRESS) {
+        luaL_unref(L, LUA_REGISTRYINDEX, nip->ping_callback_ref);
+        return luaL_error(L, "lwip error %d", err);
+    }
+    if (err == ERR_OK) {
+        NODE_DBG("[net_ping] No DNS resolution needed\n");
+        net_ping_raw(ping_target, &addr, nip);
+    }
+    return 0;
+}

app/modules/net_ping.h

@@ -0,0 +1,3 @@
+#ifdef NET_PING_ENABLE
+int net_ping(lua_State *L);
+#endif

docs/modules/net.md

@@ -626,6 +626,74 @@ Sets the IP of the DNS server used to resolve hostnames. Default: resolver1.open
 #### See also
 [`net.dns:getdnsserver()`](#netdnsgetdnsserver)
 
+
+### net.ping()
+
+Pings a server. A callback function is called when response is or is not received. Summary statistics can be retrieved via the second callback.
+
+The function can be disabled by commenting `NET_PING_ENABLE` macro in `user_config.h` when more compact build is needed.
+
+#### Syntax
+`net.ping(domain, [count], callback_received, [callback_sent])`
+
+#### Parameters
+- `domain` destination domain or IP address
+- `count` number of ping packets to be sent (optional parameter, default value is 4)
+- `callback_received(bytes, ipaddr, seqno, rtt)` callback function which is invoked when response is received where
+    - `bytes` number of bytes received from destination server (0 means no response)
+    - `ipaddr` destination server IP address
+    - `seqno` ICMP sequence number
+    - `rtt` round trip time in ms
+If domain name cannot be resolved callback is invoked with `bytes` parameter equal to 0 (i.e. no response) and `nil` values for all other parameters.
+
+- `callback_sent(ipaddr, total_count, timeout_count, total_bytes, total_time)` callback function which is invoked when response is received where
+    - `ipaddrstr` destination server IP address
+    - `total_count` total number of packets sent
+    - `timeout_count` total number of packets lost (not received)
+    - `total_bytes` total number of bytes received from destination server
+    - `total_time` total time to perform ping
+
+#### Returns
+`nil`
+
+#### Example
+```lua
+net.ping("www.nodemcu.com", function (b, ip, sq, tm) 
+    if ip then print(("%d bytes from %s, icmp_seq=%d time=%dms"):format(b, ip, sq, tm)) else print("Invalid IP address") end 
+  end)
+net.ping("www.nodemcu.com", 10, function (b, ip, sq, tm) 
+    if ip then print(("%d bytes from %s, icmp_seq=%d time=%dms"):format(b, ip, sq, tm)) else print("Invalid IP address") end 
+  end)
+net.ping("www.nodemcu.com", function (b, ip, sq, tm) 
+    if ip then print(("%d bytes from %s, icmp_seq=%d time=%dms"):format(b, ip, sq, tm)) else print("Invalid IP address") end 
+  end,
+  function (ip, tc, toc, tb, tt) 
+    print(("--- %s ping statistics ---\n%d packets transmitted, %d received, %d%% packet loss, time %dms"):format(ip, tc, tc-toc, toc/tc*100, tt)) 
+  end)
+```
+
+Multiple pings can start in short sequence thought if the new ping overlaps with the previous one the first stops receiving answers, i.e.
+```lua
+function ping_resp(b, ip, sq, tm)
+  print(string.format("%d bytes from %s, icmp_seq=%d time=%dms", b, ip, sq, tm))
+end
+
+net.ping("8.8.8.8", 4, ping_resp)
+tmr.create():alarm(1000, tmr.ALARM_SINGLE, function() net.ping("8.8.4.4", 4, ping_resp) end)
+```
+gives
+```
+32 bytes from 8.8.8.8, icmp_seq=9 time=14ms
+32 bytes from 8.8.8.8, icmp_seq=10 time=9ms
+32 bytes from 8.8.4.4, icmp_seq=11 time=6ms
+32 bytes from 8.8.4.4, icmp_seq=13 time=12ms
+0 bytes from 8.8.8.8, icmp_seq=0 time=0ms -- no more answers received
+32 bytes from 8.8.4.4, icmp_seq=15 time=16ms
+0 bytes from 8.8.8.8, icmp_seq=0 time=0ms -- no more answers received
+32 bytes from 8.8.4.4, icmp_seq=16 time=7ms
+```
+
+
 # net.cert Module
 
 This part gone to the [TLS](tls.md) module, link kept for backward compatibility.