walkthrough for creating a new module for NodeMCU

app/include/lwip/app/ping.h

@@ -75,6 +75,7 @@ struct ping_resp{
 	uint32 bytes;
 	uint32 total_bytes;
 	uint32 total_time;
+        uint8  ttl;
 	sint8  ping_err;
 };
 

app/include/user_modules.h

@@ -59,6 +59,7 @@
 //#define LUA_USE_MODULES_WS2801
 //#define LUA_USE_MODULES_WS2812
 
+#define LUA_USE_MODULES_TEST
 
 #endif  /* LUA_CROSS_COMPILER */
 #endif	/* __USER_MODULES_H__ */

app/lwip/app/ping.c

@@ -164,7 +164,8 @@ ping_recv(void *arg, struct raw_pcb *pcb, struct pbuf *p, ip_addr_t *addr)
 				  pingresp.resp_time = delay;
 				  pingresp.seqno = ntohs(iecho->seqno);
 				  pingresp.ping_err = 0;
-				  pingmsg->ping_opt->recv_function(pingmsg->ping_opt,(void*) &pingresp);
+				  pingresp.ttl = iphdr->_ttl;
+				  pingmsg->ping_opt->recv_function(pingmsg, (void*) &pingresp);
 			  }
 		  }
 		  seqno = iecho->seqno;
@@ -240,7 +241,7 @@ ping_coarse_tmr(void *arg)
 	} else {
 		uint32 delay = system_relative_time(pingmsg->ping_start);
 		delay /= PING_COARSE;
-//		ping_seq_num = 0;
+		ping_seq_num = 0;
 		if (ping_opt->sent_function == NULL){
 			os_printf("ping %d, timeout %d, total payload %d bytes, %d ms\n",
 					pingmsg->max_count, pingmsg->timeout_count, PING_DATA_SIZE*(pingmsg->max_count - pingmsg->timeout_count),delay);

app/modules/test.c

@@ -0,0 +1,186 @@
+// test.c - simple lua for playing about with
+#include "module.h"
+#include "lauxlib.h"
+#include "platform.h"
+#include "c_stdlib.h"
+
+#include "lwip/ip_addr.h"
+#include "espconn.h"
+#include "lwip/dns.h" 
+#include "lwip/app/ping.h"
+#include "lwip/raw.h"
+#include "c_stdio.h"
+
+static lua_State *gL = NULL;
+static int ping_callback_ref;
+static int ping_host_count;
+static ip_addr_t ping_host_ip;
+
+
+// test.identity() - takes a single value, returns it
+static int test_identity(lua_State *L) {  
+  return 1;
+}
+
+// test.add(x,y) - take two values and add them
+static int test_add(lua_State *L) {
+  double x = lua_tonumber(L, 1);
+  double y = lua_tonumber(L, 2);
+  lua_pushnumber(L, x+y);
+  return 1;
+}
+
+// test.add2(x,y) - take two values and add them, or take two strings and concat them
+static int test_add2(lua_State *L) {
+  if (lua_isnumber(L, 1) && lua_isnumber(L, 2)) {     
+    double x = lua_tonumber(L, 1);
+    double y = lua_tonumber(L, 2);
+    lua_pushnumber(L, x+y);
+  } else if (lua_isstring(L, 1) && lua_isstring(L, 2)) {
+    const char *s1 = lua_tostring(L, 1);
+    const char *s2 = lua_tostring(L, 2);
+    char *s = c_zalloc(strlen(s1) + strlen(s2));
+    c_sprintf(s, "%s%s", s1, s2);
+    lua_pushstring(L, s);
+  } else {
+    lua_pushnil(L);
+  }
+  return 1;
+}
+
+
+void ping_received(void *arg, void *data) {
+    struct ping_msg *pingmsg = (struct ping_msg*)arg;
+    struct ping_option *pingopt = pingmsg->ping_opt;
+    struct ping_resp *pingresp = (struct ping_resp*)data;
+
+    char ipaddrstr[16];
+    ip_addr_t source_ip;
+
+    source_ip.addr = pingopt->ip;
+    ipaddr_ntoa_r(&source_ip, ipaddrstr, sizeof(ipaddrstr));
+
+    // if we've registered a lua callback function, retrieve
+    // it from registry + call it, otherwise just print the ping
+    // response in a similar way to the standard iputils ping util
+    if (ping_callback_ref != LUA_NOREF) {
+      lua_rawgeti(gL, LUA_REGISTRYINDEX, ping_callback_ref);
+      lua_pushinteger(gL, pingresp->bytes);
+      lua_pushstring(gL, ipaddrstr);
+      lua_pushinteger(gL, pingresp->seqno);
+      lua_pushinteger(gL, pingresp->ttl);
+      lua_pushinteger(gL, pingresp->resp_time);
+      lua_call(gL, 5, 0);
+    } else {
+      c_printf("%d bytes from %s, icmp_seq=%d ttl=%d time=%dms\n",
+	       pingresp->bytes,
+	       ipaddrstr,
+	       pingresp->seqno,
+	       pingresp->ttl,
+	       pingresp->resp_time);
+    }
+}
+
+static void ping_by_hostname(const char *name, ip_addr_t *ipaddr, void *arg) {
+    struct ping_option *ping_opt = (struct ping_option *)c_zalloc(sizeof(struct ping_option));
+
+    if (ipaddr->addr == IPADDR_NONE) {
+      c_printf("problem resolving hostname\n");
+	return;
+    }
+
+    ping_opt->count = ping_host_count;
+    ping_opt->ip = ipaddr->addr;
+    ping_opt->coarse_time = 0;
+    ping_opt->recv_function = &ping_received;
+
+    ping_start(ping_opt);
+}
+
+/**
+  * test.ping()
+  * Description:
+  * 	Send ICMP ping request to address, optionally call callback when response received
+  * Syntax:
+  * 	wifi.sta.getconfig(ssid, password) --Set STATION configuration, Auto-connect by default, Connects to any BSSID
+  *     test.ping(address)              -- send 4 ping requests to target address
+  *     test.ping(address, n)           -- send n ping requests to target address
+  *     test.ping(address, n, callback) -- send n ping requests to target address
+  * Parameters:
+  * 	address: string 
+  * 	n: number of requests to send
+  * 	callback: 
+  * Returns:
+  * 	Nothing.
+  *
+  * Example:
+  *     test.ping("192.168.0.1")               -- send 4 pings to 192.168.0.1
+  *     test.ping("192.168.0.1", 10)           -- send 10 pings to 192.168.0.1
+  *     test.ping("192.168.0.1", 10, got_ping) -- send 10 pings to 192.168.0.1, call got_ping() with the
+  *                                           --     ping results
+  */
+static int test_ping(lua_State *L)
+{
+    const char *ping_target;
+    unsigned count = 4;
+
+    // retrieve address arg (mandatory)
+    if (lua_isstring(L, 1)) {
+	ping_target = luaL_checkstring(L, 1);
+    } else {
+	return luaL_error(L, "no address specified");
+    }
+
+    // retrieve count arg (optional)
+    if (lua_isnumber(L, 2)) {
+	count = luaL_checkinteger(L, 2);
+    }
+
+    // retrieve callback arg (optional)
+    if (ping_callback_ref != LUA_NOREF) 
+      luaL_unref(L, LUA_REGISTRYINDEX, ping_callback_ref);
+    ping_callback_ref = LUA_NOREF;
+
+    if (lua_type(L, 3) == LUA_TFUNCTION || lua_type(L, 3) == LUA_TLIGHTFUNCTION)
+      ping_callback_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+    gL = L;   // global L
+
+    // attempt to parse ping target as IP
+    uint32 ip = ipaddr_addr(ping_target);
+
+    if (ip != IPADDR_NONE) {
+	struct ping_option *ping_opt = (struct ping_option *)c_zalloc(sizeof(struct ping_option));
+
+	ping_opt->count = count;
+	ping_opt->ip = ip;
+	ping_opt->coarse_time = 0;
+	ping_opt->recv_function = &ping_received;
+
+	ping_start(ping_opt);
+    } else {
+	ping_host_count = count;
+
+	struct espconn *ping_dns_lookup;
+	espconn_create(ping_dns_lookup);
+	espconn_gethostbyname(ping_dns_lookup, ping_target, &ping_host_ip, ping_by_hostname);	
+    }
+
+    return 0;
+}
+
+// Module function map
+static const LUA_REG_TYPE test_map[] = {
+  { LSTRKEY( "identity" ),         LFUNCVAL( test_identity ) },
+  { LSTRKEY( "add" ),              LFUNCVAL( test_add ) },
+  { LSTRKEY( "add2" ),             LFUNCVAL( test_add2 ) },  
+  { LSTRKEY( "ping" ),             LFUNCVAL( test_ping ) },
+  { LSTRKEY( "__metatable" ),      LROVAL( test_map ) },
+  { LNILKEY, LNILVAL }
+};
+
+int luaopen_test(lua_State *L ) {
+  return 0;
+}
+
+NODEMCU_MODULE(TEST, "test", test_map, luaopen_test);