I'm having a problem using both TCP and UDP in the same sketch. What appears to happen is that if the same socket is reused for UDP after it was in use for TCP, UPD fails to receive data. I was able to reproduce this with the WebServer example. I've added to it a DNS query once in every 10 seconds to query yahoo.com IP address. The DSN queries succeed if I'm not creating any client traffic from the browser. After I query the server over HTTP over TCP, the DSN queries start to fail. DNS queries are implemented in UDP. This is the code that I'm using:
/*
Web Server
A simple web server that shows the value of the analog input pins.
using an Arduino Wiznet Ethernet shield.
Circuit:
* Ethernet shield attached to pins 10, 11, 12, 13
* Analog inputs attached to pins A0 through A5 (optional)
created 18 Dec 2009
by David A. Mellis
modified 9 Apr 2012
by Tom Igoe
modified 02 Sept 2015
by Arturo Guadalupi
*/
#include <SPI.h>
#include <Ethernet.h>
#include <Dns.h>
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};
IPAddress ip(192, 168, 1, 177);
// Initialize the Ethernet server library
// with the IP address and port you want to use
// (port 80 is default for HTTP):
EthernetServer server(80);
unsigned long t0;
void setup() {
// You can use Ethernet.init(pin) to configure the CS pin
//Ethernet.init(10); // Most Arduino shields
//Ethernet.init(5); // MKR ETH shield
//Ethernet.init(0); // Teensy 2.0
//Ethernet.init(20); // Teensy++ 2.0
//Ethernet.init(15); // ESP8266 with Adafruit Featherwing Ethernet
//Ethernet.init(33); // ESP32 with Adafruit Featherwing Ethernet
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
Serial.println("Ethernet WebServer Example");
// start the Ethernet connection and the server:
Ethernet.begin(mac, ip);
// Check for Ethernet hardware present
if (Ethernet.hardwareStatus() == EthernetNoHardware) {
Serial.println("Ethernet shield was not found. Sorry, can't run without hardware. :(");
while (true) {
delay(1); // do nothing, no point running without Ethernet hardware
}
}
if (Ethernet.linkStatus() == LinkOFF) {
Serial.println("Ethernet cable is not connected.");
}
// start the server
server.begin();
Serial.print("server is at ");
Serial.println(Ethernet.localIP());
t0 = millis();
}
void loop() {
// listen for incoming clients
EthernetClient client = server.available();
if (client) {
Serial.println("new client");
// an http request ends with a blank line
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) {
char c = client.read();
// if you've gotten to the end of the line (received a newline
// character) and the line is blank, the http request has ended,
// so you can send a reply
if (c == '\n' && currentLineIsBlank) {
// send a standard http response header
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("Connection: close"); // the connection will be closed after completion of the response
client.println("Refresh: 5"); // refresh the page automatically every 5 sec
client.println();
client.println("<!DOCTYPE HTML>");
client.println("<html>");
// output the value of each analog input pin
for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
int sensorReading = analogRead(analogChannel);
client.print("analog input ");
client.print(analogChannel);
client.print(" is ");
client.print(sensorReading);
client.println("<br />");
}
client.println("</html>");
break;
}
if (c == '\n') {
// you're starting a new line
currentLineIsBlank = true;
} else if (c != '\r') {
// you've gotten a character on the current line
currentLineIsBlank = false;
}
}
}
// give the web browser time to receive the data
delay(1);
// close the connection:
client.stop();
Serial.println("client disconnected");
}
if (millis() - t0 > 10000)
{
DNSClient dns;
dns.begin(IPAddress(8,8,8,8));
IPAddress yahoo;
if (dns.getHostByName("yahoo.com", yahoo) == 1)
{
Serial.print("Yahoo: ");
Serial.print(yahoo[0]);
Serial.print(".");
Serial.print(yahoo[1]);
Serial.print(".");
Serial.print(yahoo[2]);
Serial.print(".");
Serial.println(yahoo[3]);
}
else
{
Serial.println("Failed to query yahoo.com IP address");
}
t0 = millis();
}
}
Is this a known issue? Can someone please help in identifying the problem in my code, or if there is a workaround for this issue? Can it be a hardware issue? I'm using SunFounder boards, not the original Arduino boards.
Thanks a lot,
Boaz,
Related
I wrote a sketch for ESP8266. This sketch reads some sensor data and published it via MQTT. In addition I want to let a Web server provide the same data as HTML, or JSON web service.
The MQTT publish is triggered via a TaskScheduler timer.
Both functions, MQTT and Web server, work for itself, but sadly not together. Here's a simplified sketch:
#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
#include <ESP8266WebServerSecure.h>
#include <PubSubClient.h>
#include <TaskScheduler.h>
#include <My_WLAN.h> // provices connection to local WLAN and network settings
const char DNS_NAME[] = "myserver.local";
const int HTTPS_PORT = 443; // HTTPS
const char MQTT_SVR[] = "myserver.local";
const unsigned int MQTT_PORT = 8883; // MQTTS
WiFiClientSecure wifiClient;
PubSubClient mqttClient(wifiClient); // MQTT client instance
ESP8266WebServerSecure server(HTTPS_PORT); // web server instance
void t1Callback(void); // callback method prototypes
Task t1(60000, TASK_FOREVER, &t1Callback); // main loop task
Scheduler timer; // task scheduler
static const uint8_t SVR_FINGERPRINT[20] PROGMEM = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x20 };
static const char deviceCert[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
[... certificate ...]
-----END CERTIFICATE-----
)EOF";
static const char deviceKey[] PROGMEM = R"EOF(
-----BEGIN RSA PRIVATE KEY-----
[... key ...]
-----END RSA PRIVATE KEY-----
)EOF";
/* *****************************
MQTT_connect
* *****************************/
void MQTT_connect()
{
int attempt = 0;
/* loop until reconnected */
while (!mqttClient.connected() && attempt < 10) {
attempt++;
Serial.print("Attempting MQTT connection ("); Serial.print(attempt); Serial.print(")...");
mqttClient.setServer(MQTT_SVR, MQTT_PORT);
if (mqttClient.connect(DNS_NAME)) {
Serial.println("success");
} else {
Serial.print("failed, status code = "); Serial.print(mqttClient.state());
Serial.println(". - Try again in 5 seconds...");
delay(5000);
}
}
}
/* *****************************
Web Server handleRoot
* *****************************/
void handleRoot() {
digitalWrite(LED_BUILTIN, LOW); // on
Serial.println("WebServer ROOT");
server.send(200, "text/html", "WebServer ROOT");
digitalWrite(LED_BUILTIN, HIGH); // off
}
/* *****************************
Web Server handleNotFound
* *****************************/
void handleNotFound() {
digitalWrite(LED_BUILTIN, LOW); // on
String message = "File not found\n\n";
message += "URI: ";
message += server.uri();
message += "\nMethod: ";
message += (server.method() == HTTP_GET) ? "GET" : "POST";
message += "\nArguments: ";
message += server.args();
message += "\n";
for (uint8_t i = 0; i < server.args(); i++) {
message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
}
server.send(404, "text/plain", message);
digitalWrite(LED_BUILTIN, HIGH); // off
}
/* *************************
MQTT_publish_something
* *************************/
void MQTT_publish_something() {
digitalWrite(LED_BUILTIN, LOW); // on
char payload[30] = "some_payload_data";
if (!mqttClient.publish("MQTT/Test", payload, true)) { // retain message
Serial.println("MQTT message lost!");
}
digitalWrite(LED_BUILTIN, HIGH); // off
}
/* *************************
t1: main timer (callback)
* *************************/
void t1Callback() {
my.WiFi_connect(); // check and re-connect to WLAN (in My_WLAN.h)
if (WiFi.status() == WL_CONNECTED) {
MQTT_connect();
MQTT_publish_something();
}
}
/* *************************
setup
* *************************/
void setup() {
pinMode(LED_BUILTIN, OUTPUT); // internal LED
digitalWrite(LED_BUILTIN, HIGH); // off
/* -----------------------
open Serial |
----------------------- */
Serial.begin(74880);
while (!Serial); // wait for Serial being ready
/* -----------------------
connect to WLAN |
----------------------- */
my.WiFi_connect(); // this is connecting to WLAN & error handling (in My_WLAN.h)
wifiClient.setFingerprint(SVR_FINGERPRINT);
/* -----------------------
set mDNS |
----------------------- */
if (MDNS.begin(DNS_NAME)) {
Serial.printf("mDNS responder started for %s\n", DNS_NAME);
MDNS.addService("https", "tcp", HTTPS_PORT); // add service to MDNS-SD
MDNS.addService("mqtt", "tcp", MQTT_PORT);
} else
Serial.println("Error setting up mDNS responder!");
/* -----------------------
start HTTPS server |
----------------------- */
server.getServer().setRSACert(new X509List(deviceCert), new PrivateKey(deviceKey));
server.on("/", handleRoot); // standard HTML root
server.onNotFound(handleNotFound);
server.begin();
Serial.println("HTTPS server started.");
Serial.println();
/* -----------------------
start timer |
----------------------- */
timer.init();
timer.addTask(t1);
// line 177:
timer.enableAll();
}
void loop() {
MDNS.update();
// line 184:
server.handleClient();
mqttClient.loop();
timer.execute();
}
Running MQTT only works fine and publishes data (I use the mosquitto broker).
Running the Web server (https://...) works fine as well, if commenting out line 177 (so MQTT does not get triggered).
With both functions active, as soon as the first MQTT message had been sent, the web server does not answer any more. I get PR_END_OF_FILE_ERROR in FF and ERR_CONNECTION_CLOSED in Chrome.
I guess, that these libraries somehow mess with each other, or that something confuses with the certificates. However, the fingerprint belongs to the server running mosquitto, while the X509 certificate belongs to the web server running on the ESP8266. These are two different machines and have nothing to do with each other.
Any idea welcome.
I suspect both libraries use port 443, and you can only have one listener on a given port. I've tried creating a BearSSL::ESP8266WebServerSecure object with alternate ports, such as 80 and 8443 but can't get them to work. Worse, there doesn't seem to be a way to stop a listener once a BearSSL::ESP8266WebServerSecure object has started, so it can't be released for later reuse.
I ended up using HTTP to get WiFi credentials, then HTTPS from there on out. Not a very satisfactory solution but it works.
Update: I was able to run a provisioning server on port 443, stop it by calling
BearSSL::ESP8266WebServerSecure provisioningServer(443);
BearSSL::ESP8266WebServerSecure server(443);
provisioningServer.close();
provisioningServer.~ESP8266WebServerSecure(); // note: cannot use TLS on both servers without this line
After calling the provisioning server's destructor I was able to start my server on port 443.
I am trying to send and receive a messages from Raspberry Pi (Broker) to Arduino-ESP8266 (client) using MQTT. What I am trying to achieve is pretty basic for now. The broker sends a start command and the client on receving the message should send back a random number. I am able to read the message sent by the broker but the messages from the client are never sent. Here is the code that I am using
#include <WiFiEsp.h>
#include <WiFiEspClient.h>
#ifndef HAVE_HWSERIAL1
#include "SoftwareSerial.h"
SoftwareSerial Serial1(19, 18); //RX, TX
#endif
#define MQTT_KEEPALIVE 10
#include <PubSubClient.h>
IPAddress server(192, 168, 0, 105);
char ssid[] = "user1956";
char password[] = "******";
int status = WL_IDLE_STATUS; //wifi radio's status
//MQTT
//const char* mqtt_topic = "Rpi_Master";
const char* mqtt_username = "pi";
const char* mqtt_password = "********";
//client Id
const char* clientID = "A_2";
//Variables for numbers
long randNumber1;
String rn1;
char rn1_char[50];
WiFiEspClient wifiClient;
PubSubClient client(wifiClient); //1883 is the listener port for the broker
void setup() {
// Initilize serial for debugging
Serial.begin(115200);
//initilize serial for ESP module
Serial1.begin(115200);
//initilize the ESP module
WiFi.init(&Serial1);
if (WiFi.status() == WL_NO_SHIELD)
{
Serial.println("WiFi shield not present");
while (true);
}
while (status != WL_CONNECTED)
{
Serial.print("Attempting to connect to WPA SSID : ");
Serial.println(ssid);
status = WiFi.begin(ssid, password);
}
Serial.println("You are connected to the network");
client.setServer(server, 1883);
client.setCallback(callback);
//Allow the hardware to sort itself
delay(1500);
randomSeed(50);
}
void callback(char* topic, byte* payload, unsigned int length)
{
Serial.print("Message Received: [");
Serial.print(topic);
Serial.println("]");
Serial.print("Message is:");
String message = (char *)payload;
Serial.println(message);
else if (!strncmp((char *)payload, "B1", length)) //Start code can be changed to any string value in place of 1
{
client.publish("Ad_B", "OK");
generateRandomData();
}
else if (!strncmp((char *)payload, "B2", length)) //Start code can be changed to any string value in place of 1
{
client.publish("Ad_B", "OK");
generateRandomData();
}
}
void loop()
{
if (!client.connected())
{
reconnect();
}
client.loop();
delay(1000);
}
void reconnect()
{
while (!client.connected())
{
Serial.print("Attempting MQTT Connection...");
//Attempt to Connect
if (client.connect(clientID, mqtt_username, mqtt_password))
{
Serial.println("connected");
//Once connected publish an announcement
client.publish("Ad_B", "Ready");
//and resubscribe
client.subscribe("Rpi_Master"); //This name can be changed
}
else
{
Serial.print("failed, rc = ");
Serial.print(client.state());
Serial.println("Trying again in 5 seconds");
//Wait for 5 seconds before retrying
delay(5000);
}
}
}
void generateRandomData(){
randNumber1 = random(0,0); //(14000,15000)
//Serial.println(randNumber1); // print a random number from 0to 299
rn1 = String(randNumber1);
rn1.toCharArray(rn1_char, rn1.length() + 1);
client.publish("LC_B_1", rn1_char);
client.publish("Ad_B", "End");
}
This is the output of the serial monitor that I am receiving:
07:45:42.016 -> [WiFiEsp] Initializing ESP module
07:45:45.430 -> [WiFiEsp] Initilization successful - 1.5.4
07:45:45.430 -> Attempting to connect to WPA SSID : No Free Wifi
07:45:50.464 -> [WiFiEsp] Connected to No Free Wifi
07:45:50.464 -> You are connected to the network
07:45:51.940 -> Attempting MQTT Connection...[WiFiEsp] Connecting to 192.168.0.105
07:45:52.084 -> connected
07:46:31.926 -> Message Received: [Rpi_Master]
07:46:31.926 -> Message is:B2ter
07:46:37.438 -> [WiFiEsp] TIMEOUT: 20
08:20:58.967 -> [WiFiEsp] >>> TIMEOUT >>>
The client is unable to publish any messages. The mosquitto log shows PINGREQ and RINGRESP to a random id and client.publish stops with the following message in the log - Socket Error on Client <Some Random Client Id>, Disconnecting. Attached the screenshot of the log. Is there any way to know what the unknown client is? Please help me to sort this issue. Thanks.
You generateRandom() function blocks (15 seconds) for longer than the keep alive (10 seconds) timeout and this will block the client.loop() function so it will not be able to send keep alive packets.
I am currently working on a project that involves an arduino uno and an ethernet shield. I am using a sketch from Randomnerdtutorials.com (with slight changes to fit my router) which I will provide. The server that the ethernet shield creates does show up and work when I put the IP address in the URL bar (192.168.1.178:8080) The ethernet shield itself however does not show up on my list of attached devices to my Netgear router. It does occasionally but then disappears. Any ideas? I looked at another thread that stated to replace
Ethernet.begin(mac, ip, gateway, subnet);
with
Ethernet.begin(mac);
but that did not work. Any ideas are welcome. Here is the full code
/*
Created by Rui Santos
Visit: http://randomnerdtutorials.com for more arduino projects
Arduino with Ethernet Shield
*/
#include <SPI.h>
#include <Ethernet.h>
#include <Servo.h>
int led = 4;
Servo microservo;
int pos = 0;
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 192, 168, 1, 178 }; // ip in lan (that's what you need to use in your browser. ("192.168.1.178")
byte gateway[] = { 192, 168, 1, 130 }; // internet access via router
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
EthernetServer server(8080); //server port
String readString;
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
pinMode(led, OUTPUT);
microservo.attach(7);
// start the Ethernet connection and the server:
Ethernet.begin(mac, ip, gateway, subnet);
// Ethernet.begin(mac);
server.begin();
Serial.print("server is at ");
Serial.println(Ethernet.localIP());
}
void loop() {
// Create a client connection
EthernetClient client = server.available();
if (client) {
while (client.connected()) {
if (client.available()) {
char c = client.read();
//read char by char HTTP request
if (readString.length() < 100) {
//store characters to string
readString += c;
//Serial.print(c);
}
//if HTTP request has ended
if (c == '\n') {
Serial.println(readString); //print to serial monitor for debuging
client.println("HTTP/1.1 200 OK"); //send new page
client.println("Content-Type: text/html");
client.println();
client.println("<HTML>");
client.println("<HEAD>");
client.println("<meta name='apple-mobile-web-app-capable' content='yes' />");
client.println("<meta name='apple-mobile-web-app-status-bar-style' content='black-translucent' />");
client.println("<link rel='stylesheet' type='text/css' href='http://randomnerdtutorials.com/ethernetcss.css' />");
client.println("<TITLE>Random Nerd Tutorials Project</TITLE>");
client.println("</HEAD>");
client.println("<BODY>");
client.println("<H1>Random Nerd Tutorials Project</H1>");
client.println("<hr />");
client.println("<br />");
client.println("<H2>Arduino with Ethernet Shield</H2>");
client.println("<br />");
client.println("Turn On LED");
client.println("Turn Off LED<br />");
client.println("<br />");
client.println("<br />");
client.println("Rotate Left");
client.println("Rotate Right<br />");
client.println("<p>Created by Rui Santos. Visit http://randomnerdtutorials.com for more projects!</p>");
client.println("<br />");
client.println("</BODY>");
client.println("</HTML>");
delay(1);
//stopping client
client.stop();
//controls the Arduino if you press the buttons
if (readString.indexOf("?button1on") >0){
digitalWrite(led, HIGH);
}
if (readString.indexOf("?button1off") >0){
digitalWrite(led, LOW);
}
if (readString.indexOf("?button2on") >0){
for(pos = 0; pos < 180; pos += 3) // goes from 0 degrees to 180 degrees
{ // in steps of 1 degree
microservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
}
if (readString.indexOf("?button2off") >0){
for(pos = 180; pos>=1; pos-=3) // goes from 180 degrees to 0 degrees
{
microservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
}
//clearing string for next read
readString="";
}
}
}
}
}
Looks like the problem is with DHCP. Try
if (Ethernet.begin(mac) == 0) {
Serial.println("Failed to configure Ethernet using DHCP");
// try to congifure using IP address instead of DHCP:
Ethernet.begin(mac, ip);
}
else{Serial.println("DHCP OK!");
and see if it gives DHCP failure
I have a functional server code with only TCP connection. Now I want the server to receive from UDP connection. I have used port 2000 for TCP & port 2001 for UDP. Here is a snippet of my code
struct timeval timeout; // timeout for select(), 1ms
timeout.tv_sec = 0;
timeout.tv_usec = 1000;
fd_set master; // master file descriptor list
fd_set read_fds; // temp file descriptor list for select()
int fdmax; // maximum file descriptor number
FD_ZERO(&master); // clear the master and temp sets
FD_ZERO(&read_fds);
// TCP port setup
int sockfd; // listening socket descriptor
int newsockfd; // newly accept()ed socket descriptor
struct sockaddr_storage remoteaddr; // client address
socklen_t addrlen;
char buf_tcp[256]; // buffer for client data
char buf_copy_tcp[256];
int recv_bytes;
char remoteIP[INET6_ADDRSTRLEN];
int yes=1; // for setsockopt() SO_REUSEADDR
int i, k, rv_getaddrinfo, rv_setsockopt, rv_bind, rv_listen, rv_select;
struct addrinfo hints, *servinfo, *ptr;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
rv_getaddrinfo = getaddrinfo(NULL, "2000", &hints, &servinfo);
for(ptr=servinfo; ptr!=NULL; ptr=ptr->ai_next)
{
sockfd = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
rv_setsockopt = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
rv_bind = bind(sockfd, ptr->ai_addr, ptr->ai_addrlen);
break;
}
if (ptr == NULL)
{
fprintf(stderr, "CLI Server error: failed to bind\n\r");
exit(2);
}
freeaddrinfo(servinfo); // all done with this
rv_listen = listen(sockfd, 10);
////////////////////////////////////////////////////////////////////////////////////////////////
// UDP port setup
int sockfd_udp; // listening socket descriptor
struct sockaddr_storage remoteaddr_udp; // client address
socklen_t addrlen_udp;
char buf_udp[256]; // buffer for client data
char buf_copy_udp[256];
int recv_bytes_udp;
char remoteIP_udp[INET6_ADDRSTRLEN];
int yes_udp=1; // for setsockopt() SO_REUSEADDR
int j, rv_getaddrinfo_udp, rv_setsockopt_udp, rv_bind_udp;
struct addrinfo hints_udp, *servinfo_udp, *ptr_udp;
memset(&hints_udp, 0, sizeof(hints_udp));
hints_udp.ai_family = AF_UNSPEC;
hints_udp.ai_socktype = SOCK_DGRAM;
hints_udp.ai_flags = AI_PASSIVE;
rv_getaddrinfo_udp = getaddrinfo(NULL, "2001", &hints_udp, &servinfo_udp);
for(ptr_udp=servinfo_udp; ptr_udp!=NULL; ptr_udp=ptr_udp->ai_next)
{
sockfd_udp = socket(ptr_udp->ai_family, ptr_udp->ai_socktype, ptr_udp->ai_protocol);
rv_setsockopt_udp = setsockopt(sockfd_udp, SOL_SOCKET, SO_REUSEADDR, &yes_udp, sizeof(int));
rv_bind_udp = bind(sockfd_udp, ptr_udp->ai_addr, ptr_udp->ai_addrlen);
break;
}
if (ptr_udp == NULL)
{
fprintf(stderr, "CLI UDP Server error: failed to bind\n\r");
exit(2);
}
freeaddrinfo(servinfo_udp); // all done with this
//////////////////////////////////////////////////////////////////////////////////////////////////////////
// add the listener to the master set
FD_SET(sockfd, &master);
FD_SET(sockfd_udp, &master);
// keep track of the biggest file descriptor
if(sockfd > sockfd_udp)
fdmax = sockfd; // so far, it's this one
else
fdmax = sockfd_udp; // so far, it's this one
do
{
read_fds = master; // copy it
rv_select = select(fdmax+1, &read_fds, NULL, NULL, &timeout);
// run through the existing connections looking for data to read
for(i=0; i<=fdmax; i++)
{
if (FD_ISSET(i, &read_fds))
{ // we got one!!
if (i == sockfd)
{
// handle new connections
addrlen = sizeof(remoteaddr);
newsockfd = accept(sockfd, (struct sockaddr *)&remoteaddr, &addrlen);
FD_SET(newsockfd, &master); // add to master set
if (newsockfd > fdmax) // keep track of the max
fdmax = newsockfd;
inet_ntop(remoteaddr.ss_family, get_in_addr((struct sockaddr*)&remoteaddr), remoteIP, INET6_ADDRSTRLEN);
fprintf(stdout, "CLI Server: new connection from %s on socket %d\n\r", remoteIP, newsockfd);
}
else if (i == sockfd_udp)
{
// handle new udp connections
addrlen_udp = sizeof(remoteaddr_udp);
recv_bytes_udp = recvfrom(i, buf_udp, sizeof(buf_udp), 0, (struct sockaddr *)&remoteaddr_udp, &addrlen_udp);
inet_ntop(remoteaddr_udp.ss_family, get_in_addr((struct sockaddr*)&remoteaddr_udp), remoteIP_udp, INET6_ADDRSTRLEN);
for(j=0; j<=recv_bytes_udp; j++)
{
if( (buf_udp[k] == '\r') | (buf_udp[k] == '\n') )
buf_udp[k] = '\0';
}
fprintf(stdout, "CLI UDP Server: received %s from connection %s\n\r", buf_udp, remoteIP_udp);
}
else
{ // handle data from a client
if ((recv_bytes = recv(i, buf_tcp, sizeof(buf_tcp), 0)) <= 0)
{ // got error or connection closed by client
if (recv_bytes == 0) // connection closed
{
fprintf(stdout, "CLI Server: socket %d hung up\n\r", i);
}
else
{
perror("CLI Server error: recv");
exit(6);
}
close(i); // bye!
FD_CLR(i, &master); // remove from master set
}
else
{
for(k=0; k<=recv_bytes; k++)
{
if( (buf_tcp[k] == '\r') | (buf_tcp[k] == '\n') )
buf_tcp[k] = '\0';
}
fprintf(stdout, "CLI Server: received %s from socket %d\n\r", buf_tcp, i);
}
} // END handle data from client
} // END got new incoming connection
} // END looping through file descriptors
} while(QUIT);
I am doing error checking at each stage but didn't include it in the snippet. When I compile & run this, I can connect to port 2000 but not to 2001, my Tera term terminal closes with connection refused message. Why is the client not able to connect to port 2001 (UDP socket) but connects to port 2000 (TCP socket). The server just responds to client messages until client enters QUIT.
I have modeled this code from Beej's Guide to Network Programming selectserver.c code.
The program that I wrote above was correct but my understanding of socket programming was not. It was a fluke that I managed to write correct code but thanks to #EJP for having an extended discussion in the comments to clear up my doubt.
My mistake was using Teraterm's TCP client to connect to a UDP server. Both communications are mutually exclusive & hence can't communicate with one another. So I had to use a UDP client. Netcat provides an option of UDP client using netcat -u <ip address> <port>. Then my UDP server was able to receive messages from UDP client.
Another mistake was confusing bind() with connect() in DATAGRAM sockets. A connected DGRAM is when I use connect on both server & client.
I thought the problem was with select(), as I wrongly thought that UDP & TCP sockets can't be used simultaneously in select(). But the above code is how you write a UDP/TCP server for multiple client.
Thanks again to Beej & #EJP
I wrote a small C/C++ Windows Mobile 6.5 client-application that is connecting to a server and sends some data to this server. The server is in my internal wireless network and is not reacheable outside.
The weird behaviour I'm having:
1) Even if the WIFI is not started on my mobile device, the connect() from the client-application returns success (!= SOCKET_ERROR), which is not the case b/c the server is reacheable only in the wireless network.
2) If the WIFI is not started on my mobile device, if there is a Sleep(1000) between the connect() and the send(), the send() fails with WSAECONNRESET, BUT if there is no Sleep() between the connect() and send() the send() succeeds! (only when doing the read() I finally get the WSAECONNRESET error).
Can somebody pls point me some tips why do I have this behaviour. It's pretty scary that without actually being able to reach the server I still get success for the connect() and for the send() :(
As requested, here is a sample code:
#include <windows.h>
#include <Winsock2.h>
#include "dbgview.h"
# define FxMemZero(buf,len) RtlZeroMemory ((VOID*)(buf),(SIZE_T)(len))
# define FxMemCopy(dst,src,len) RtlCopyMemory ((VOID*)(dst),(CONST VOID*)(src),(SIZE_T)(len))
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
int nCmdShow)
{
SOCKET proxy_connection;
WSADATA wsadata;
if( 0 != WSAStartup (MAKEWORD(1, 1), &wsadata))
return -1;
proxy_connection = WSASocket (AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, 0);
if(proxy_connection == INVALID_SOCKET) {
// error creating the socket
DbgViewTraceError((L"main", L"error creating socket."));
return -1;
}
// try to connect
UINT proxy_ip_ = 0x00000000;
CHAR* proxy_0_ = "192.168.1.105";
UINT proxy_port = 3100;
// get the proxy ip
{
struct hostent *he_;
if((he_ = gethostbyname(proxy_0_)) == NULL) {
DbgViewTraceWarning((L"main", L"error %d resolving hostname %hs", WSAGetLastError(), proxy_0_));
return -1;
}
FxMemCopy((PBYTE)&proxy_ip_, (PBYTE)he_->h_addr, he_->h_length);
}
// prepare the connection data
sockaddr_in saddr_;
FxMemZero(&saddr_,sizeof(sockaddr_in));
saddr_.sin_family = AF_INET;
saddr_.sin_addr.S_un.S_addr = proxy_ip_;// address
saddr_.sin_port = htons((USHORT)proxy_port);
// do the conection
if(SOCKET_ERROR == connect(proxy_connection, (SOCKADDR*) &saddr_, sizeof(saddr_))) {
// error connecting to the proxy
DbgViewTraceWarning(( L"main", L"error %d connecting to %hs:%d", WSAGetLastError(), proxy_0_, proxy_port));
closesocket(proxy_connection);
proxy_connection = INVALID_SOCKET;
return -1;
}
DbgViewTraceInfo(( L"main", L"SUCCESS. connected to %hs:%d.", proxy_0_, proxy_port));
CHAR* buffer_ = "Momo";
UINT count_ = strlen(buffer_);
DWORD total_ = 0;
DWORD sent_ = 0;
while(total_ < count_) {
// ISSUE: IF the WIFI is not started on the mobile, the connect returns success AND the send() returns success, even though with putty
// on the mobile, a telnet on 192.168.1.105:3100 will fail with: "Network error: Connection reset by peer"
// IF I add a long-enough Sleep() between the connect() and the send(), the send() will fail with: WSAECONNRESET
//Sleep(5000);
if(SOCKET_ERROR == (sent_ = send(proxy_connection, (const char*)buffer_ + total_, count_ - total_, 0))) {
// error sending data to the socket
DbgViewTraceError((L"main", L"error %d sending data to proxy", WSAGetLastError()));
return -1;
}
total_ += sent_;
}
DbgViewTraceInfo((L"main", L"send() SUCCESS"));
return 0;
}
The results are:
1) Without Sleep():
main [INFO ] SUCCESS. connected to 192.168.1.105:3100.
main [INFO ] send() SUCCESS
2) With Sleep():
main [INFO ] SUCCESS. connected to 192.168.1.105:3100.
main [ERROR ] error 10054 sending data to proxy
So the questions are:
1) Why the connect() succeeds? How can I be sure that there is actually a real connection?
2) Why the send() succeeds?
3) Why with a Sleep() in between connect() and send() the behaviour is different?
The problem seems to be ActiveSync. If ActiveSync is running, I get the behavior described above (connect() and send() report success, even though they are not). If ActiveSync is not running, gethostbyname() fails with:
WSAENETDOWN -> if WIFI is disabled
WSAHOST_NOT_FOUND -> if WIFI is enabled
which is correct!
How can this be? What is ActiveSync doing that is ruining everything? How can I avoid this problem? I mean, I can't be sure that the user is running my application when there is no ActiveSync running, so what can I do to avoid this behavior when ActiveSync is running?
Thx,
MeCoco
Looks like you are at least misusing struct sockaddr_in. Try more modern API for address conversion - Windows has InetPton - and see if that fixes the issues.