Pages: [1] 2 3   Go Down
Author Topic: W5100/Ethernet cannot use socket as UDP after using it as TCP  (Read 4209 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

So here's the issue.  If I use any of the 4 W5100 sockets as at TCP socket that sends/receives data, it seems to disqualify that socket from sending out UDP datagrams anymore.  Calling a W5100.init() seems to fix the issue, but of course that resets all of my sockets.
Has anyone experienced this before? 
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

So I've dummied up a test case from some of the Arduino samples.  All this does is create a TCP server on port 80, and every 10 seconds it'll poll an NTP server via UDP.  Here's what will happen:
* It'll start listening on port 80 (W5100 socket #0)
* It'll do the NTP stuff from port 8888 on W5100 socket #1.  (this works fine).
* It'll continue to do the NTP stuff every 10 seconds indefinitely and successfully.
* If you connect to the port 80 (e.g. browse there with a web server), it'll service the request on socket 0, and open a new listening port on socket 1, and then terminate socket 0.
* The NTP stuff continues every 10 seconds, but this time it's on socket 0.  It works..
* Browse to port 80 again.  This time it'll service on socket 1.
* NTP never works again.  Web server works just fine forever...

Here's the sketch.
Code:
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <utility/W5100.h>

void ShowSockStatus()
{
for (int i = 0; i < MAX_SOCK_NUM; i++) {
Serial.print("Socket#");
Serial.print(i);
uint8_t s = W5100.readSnSR(i);
Serial.print(":0x");
Serial.print(s,16);
Serial.print(" ");
Serial.print(W5100.readSnPORT(i));
Serial.print(" D:");
uint8_t dip[4];
W5100.readSnDIPR(i, dip);
for (int j=0; j<4; j++) {
Serial.print(dip[j],10);
if (j<3) Serial.print(".");
}
Serial.print("(");
Serial.print(W5100.readSnDPORT(i));
Serial.println(")");
}
}

byte mac[] = {  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

EthernetServer server(80);
IPAddress timeServer(192,168,10,1);
IPAddress ip(192,168,10,20);
IPAddress gateway(192,168,10, 2);
IPAddress subnet(255, 255, 255, 0);

long timer;

void setup() {
Serial.begin(9600);
Ethernet.begin(mac, ip, INADDR_NONE, gateway, subnet);
delay(500);

Serial.println("Start!");
server.begin();
ShowSockStatus();
timer = millis();
}

const int NTP_PACKET_SIZE= 48; // NTP time stamp is in the first 48 bytes of the message
byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets

// send an NTP request to the time server at the given address
unsigned long sendNTPpacket(EthernetUDP & Udp, IPAddress& address)
{

// set all bytes in the buffer to 0
memset(packetBuffer, 0, NTP_PACKET_SIZE);
// Initialize values needed to form NTP request
// (see URL above for details on the packets)
packetBuffer[0] = 0b11100011;   // LI, Version, Mode
packetBuffer[1] = 0;     // Stratum, or type of clock
packetBuffer[2] = 6;     // Polling Interval
packetBuffer[3] = 0xEC;  // Peer Clock Precision
// 8 bytes of zero for Root Delay & Root Dispersion
packetBuffer[12]  = 49;
packetBuffer[13]  = 0x4E;
packetBuffer[14]  = 49;
packetBuffer[15]  = 52;

// all NTP fields have been given values, now
// you can send a packet requesting a timestamp:    
Udp.beginPacket(address, 123); //NTP requests are to port 123
Udp.write(packetBuffer,NTP_PACKET_SIZE);
Udp.endPacket();
}

void checkTime()
{
EthernetUDP Udp;
Udp.begin(8888);
sendNTPpacket(Udp, timeServer); // send an NTP packet to a time server
Serial.println("");
ShowSockStatus();
// wait to see if a reply is available
delay(1000); 
if ( Udp.parsePacket() ) { 
// We've received a packet, read the data from it
Udp.read(packetBuffer,NTP_PACKET_SIZE);  // read the packet into the buffer

//the timestamp starts at byte 40 of the received packet and is four bytes,
// or two words, long. First, esxtract the two words:

unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]); 
// combine the four bytes (two words) into a long integer
// this is NTP time (seconds since Jan 1 1900):
unsigned long secsSince1900 = highWord << 16 | lowWord; 

// now convert NTP time into everyday time:
Serial.print("Unix time = ");
// Unix time starts on Jan 1 1970. In seconds, that's 2208988800:
const unsigned long seventyYears = 2208988800UL;     
// subtract seventy years:
unsigned long epoch = secsSince1900 - seventyYears; 
// print Unix time:
Serial.println(epoch); 

else
Serial.println("UDP FAIL!");
Udp.stop();

}

void loop()
{
//Check if a web client has attached.
EthernetClient client = server.available();
if (client) {
Serial.println("new Client");
ShowSockStatus();
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) {
char c = client.read();
Serial.print(c);
if (c == '\n' && currentLineIsBlank) {
client.stop();
}
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() - timer) > 10000) {
timer = millis();
checkTime();
}
}
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I loaded up your sketch and tested it. I changed only the network settings and the NTP server ip since I have my own NTP server here. It works ok, except the webpage says "No data received". I made several requests, and the NTP client is still running fine.

For those Linux users out there, you must change this include.
#include <utility/W5100.h>
to
#include <utility/w5100.h>
File names are case sensitive in linux.
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

How very strange.  I'm using 1.0.4 also.  I've verified this on two different Ethernet Shields and a bunch of different Megas and Unos.  I wonder if there were different versions of the W5100 chip released?  What output do you get? 

Here's mine:
Code:
Start!
Socket#0:0x14 80 D:0.0.0.0(0)
Socket#1:0x0 0 D:0.0.0.0(0)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)

Socket#0:0x14 80 D:0.0.0.0(0)
Socket#1:0x22 8888 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
Unix time = 1366986649

Socket#0:0x14 80 D:0.0.0.0(0)
Socket#1:0x22 8888 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
Unix time = 1366986659

Socket#0:0x14 80 D:0.0.0.0(0)
Socket#1:0x22 8888 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
Unix time = 1366986669
new Client
Socket#0:0x17 80 D:192.168.10.213(9129)
Socket#1:0x14 80 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
GET / HTTP/1.1
Host: 192.168.10.20
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
If-Modified-Since: Fri, 02 Jun 2006 09:46:32 GMT

client disconnected

Socket#0:0x22 8888 D:192.168.10.1(123)
Socket#1:0x14 80 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
Unix time = 1366986679
new Client
Socket#0:0x14 80 D:192.168.10.1(123)
Socket#1:0x17 80 D:192.168.10.213(9132)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
GET / HTTP/1.1
Host: 192.168.10.20
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

client disconnected

Socket#0:0x14 80 D:192.168.10.1(123)
Socket#1:0x22 8888 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
UDP FAIL!

Socket#0:0x14 80 D:192.168.10.1(123)
Socket#1:0x22 8888 D:192.168.10.1(123)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
UDP FAIL!

Once it goes into fail mode it'll never come back **for that socket**.  However, if you play around with refreshing your browser you can sometimes get it to bounce to a different socket and then it'll work.  (at least until that socket also has had a TCP conversation on it)  I've also verified through tcpdump packet capture that the packet doesn't actually get sent. 
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

This worked for me. You did have some errors in that code that did not manifest themselves first pass, but did on a second. I moved the Udp.begin() to setup() and commented out the Udp.stop(). I also used my server code.
Code:
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <utility/w5100.h>

void ShowSockStatus()
{
for (int i = 0; i < MAX_SOCK_NUM; i++) {
Serial.print("Socket#");
Serial.print(i);
uint8_t s = W5100.readSnSR(i);
Serial.print(":0x");
Serial.print(s,16);
Serial.print(" ");
Serial.print(W5100.readSnPORT(i));
Serial.print(" D:");
uint8_t dip[4];
W5100.readSnDIPR(i, dip);
for (int j=0; j<4; j++) {
Serial.print(dip[j],10);
if (j<3) Serial.print(".");
}
Serial.print("(");
Serial.print(W5100.readSnDPORT(i));
Serial.println(")");
}
}

byte mac[] = {  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

EthernetServer server(80);
IPAddress timeServer(198,55,111,50);

IPAddress ip(192,168,2,2);
IPAddress gateway(192,168,2, 1);
IPAddress subnet(255, 255, 255, 0);

long timer;
EthernetUDP Udp;

void setup() {
Serial.begin(9600);

        pinMode(4, OUTPUT);
        digitalWrite(4, HIGH);
       
Ethernet.begin(mac, ip, INADDR_NONE, gateway, subnet);
delay(500);
Udp.begin(8888);

Serial.println("Start!");
server.begin();
ShowSockStatus();
timer = millis();
}

const int NTP_PACKET_SIZE= 48; // NTP time stamp is in the first 48 bytes of the message
byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets

// send an NTP request to the time server at the given address
unsigned long sendNTPpacket(EthernetUDP & Udp, IPAddress& address)
{

// set all bytes in the buffer to 0
memset(packetBuffer, 0, NTP_PACKET_SIZE);
// Initialize values needed to form NTP request
// (see URL above for details on the packets)
packetBuffer[0] = 0b11100011;   // LI, Version, Mode
packetBuffer[1] = 0;     // Stratum, or type of clock
packetBuffer[2] = 6;     // Polling Interval
packetBuffer[3] = 0xEC;  // Peer Clock Precision
// 8 bytes of zero for Root Delay & Root Dispersion
packetBuffer[12]  = 49;
packetBuffer[13]  = 0x4E;
packetBuffer[14]  = 49;
packetBuffer[15]  = 52;

// all NTP fields have been given values, now
// you can send a packet requesting a timestamp:    
Udp.beginPacket(address, 123); //NTP requests are to port 123
Udp.write(packetBuffer,NTP_PACKET_SIZE);
Udp.endPacket();
}

void checkTime()
{
sendNTPpacket(Udp, timeServer); // send an NTP packet to a time server
Serial.println("");
ShowSockStatus();
// wait to see if a reply is available
delay(1000); 
if ( Udp.parsePacket() ) { 
// We've received a packet, read the data from it
Udp.read(packetBuffer,NTP_PACKET_SIZE);  // read the packet into the buffer

//the timestamp starts at byte 40 of the received packet and is four bytes,
// or two words, long. First, esxtract the two words:

unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]); 
// combine the four bytes (two words) into a long integer
// this is NTP time (seconds since Jan 1 1900):
unsigned long secsSince1900 = highWord << 16 | lowWord; 

// now convert NTP time into everyday time:
Serial.print("Unix time = ");
// Unix time starts on Jan 1 1970. In seconds, that's 2208988800:
const unsigned long seventyYears = 2208988800UL;     
// subtract seventy years:
unsigned long epoch = secsSince1900 - seventyYears; 
// print Unix time:
Serial.println(epoch); 

else
Serial.println("UDP FAIL!");
// Udp.stop();

}

void loop()
{
//Check if a web client has attached.
        checkServer();
       
if ((millis() - timer) > 10000) {
timer = millis();
checkTime();
}
}


void checkServer()
{
  EthernetClient client = server.available();
  if(client) {
    boolean currentLineIsBlank = true;
    boolean currentLineIsGet = true;
    int tCount = 0;
    char tBuf[64];
    int r,t;
    char *pch;

    Serial.print(F("Client request: "));

    // this controls the timeout
    int loopCount = 0;

    while (client.connected()) {
      while(client.available()) {
        // if packet, reset loopCount
        loopCount = 0;
        char c = client.read();

        if(currentLineIsGet && tCount < 63)
        {
          tBuf[tCount] = c;
          tCount++;
          tBuf[tCount] = 0;         
        }

        if (c == '\n' && currentLineIsBlank) {
          // send a standard http response
          Serial.println(tBuf);
          Serial.print(F("POST data: "));
          while(client.available()) Serial.write(client.read());
          Serial.println();

          pch = strtok(tBuf,"?");

          while(pch != NULL)
          {
            if(strncmp(pch,"t=",2) == 0)
            {
              t = atoi(pch+2);
              Serial.print("t=");
              Serial.println(t,DEC);             
            }

            if(strncmp(pch,"r=",2) == 0)
            {
              r = atoi(pch+2);
              Serial.print("r=");             
              Serial.println(r,DEC);
            }


            pch = strtok(NULL,"& ");
          }
          Serial.println(F("Sending response"));
          client.print(F("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n<html>"));
          client.println(F("<body><H1>TEST</H1>"));
          client.println(F("<form method=GET>T: <input type=text name=t><br>"));
          client.println(F("R: <input type=text name=r><br><input type=submit></form>"));


          client.println(F("</body></html>"));
          client.stop();
        }
        else if (c == '\n') {
          currentLineIsBlank = true;
          currentLineIsGet = false;
        }
        else if (c != '\r') {
          currentLineIsBlank = false;
        }
      }

      loopCount++;

      // if 10000ms has passed since last packet
      if(loopCount > 10000) {
        // close connection
        client.stop();
        Serial.println("\r\nTimeout");
      }

      // delay 1ms for timeout timing
      delay(1);
    }
    Serial.println(F("done"));
  }
}
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Here is the serial monitor for that:
Quote
Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3287)
Socket#2:0x0 80 D:192.168.1.254(3286)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366989984
Client request: GET /?t=&r= HTTP/1.1

POST data:
t=0
r=0
Sending response
done
Client request: GET /favicon.ico HTTP/1.1

POST data:
Sending response
done

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3291)
Socket#2:0x0 80 D:192.168.1.254(3292)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366989994

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3291)
Socket#2:0x0 80 D:192.168.1.254(3292)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366990004

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3291)
Socket#2:0x0 80 D:192.168.1.254(3292)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366990014

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3291)
Socket#2:0x0 80 D:192.168.1.254(3292)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366990024

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3291)
Socket#2:0x0 80 D:192.168.1.254(3292)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366990034

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3291)
Socket#2:0x0 80 D:192.168.1.254(3292)
Socket#3:0x0 80 D:192.168.1.254(3290)
Unix time = 1366990044
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Dude.  Thanks a ton.  I appreciate immensely what you're doing here.  Unfortunately that's not exactly the same use case.  You only refreshed the browser once.  Notice that in my example after the first time I refreshed I still got responses back from the NTP, but after the second time I refreshed, the NTP stopped. Seems odd, but here's my explanation:

It seems that it's actually related to transition from UDP to a listening socket->connected transition, to being used for UDP again.  When you refresh the first time, you're using socket 0 (which has never been used for UDP) to do the TCP, and the listening port goes to socket 1.  The UDP time server then happens on socket 0 which hasn't been used for UDP *before* TCP.  If you wait about 10 seconds and then refresh, it'll use socket 1 to do the TCP conn, and then listen back on socket 0.  At that point the UDP will take place on socket 1 (which has done the UDP to TCP transition) and it will fail.

Ugh.  this is too complicated a scenario here.  Sorry sorry sorry.  I'm wondering if you can do 1 more test:
1.  Start the code.
2.  wait about 15 seconds.
3.  refresh your browser.
4.  wait about 15 seconds.
5.  refresh your browser again.

Incidentally, I tried to make a simpler scenario by writing some code that connects to itself, but apparently the W5100 won't connect to itself.
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Like this?
Quote
Start!
Socket#0:0x22 8888 D:0.0.0.0(0)
Socket#1:0x14 80 D:0.0.0.0(0)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
Client request: GET / HTTP/1.1

POST data:
Sending response
done

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x0 80 D:192.168.1.254(3719)
Socket#2:0x17 80 D:192.168.1.254(3720)
Socket#3:0x14 80 D:0.0.0.0(0)
Unix time = 1366996102
Client request: GET /?t=4&r=3 HTTP/1.1

POST data:
t=4
r=3
Sending response
done

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x0 80 D:192.168.1.254(3719)
Socket#2:0x0 80 D:192.168.1.254(3720)
Socket#3:0x14 80 D:0.0.0.0(0)
Unix time = 1366996112
Client request: GET /?t=5&r=1 HTTP/1.1

POST data:
t=5
r=1
Sending response
done

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x14 80 D:192.168.1.254(3719)
Socket#2:0x0 80 D:192.168.1.254(3720)
Socket#3:0x0 80 D:192.168.1.254(3724)
Unix time = 1366996122
Client request: GET /?t=5&r=1 HTTP/1.1

POST data:
t=5
r=1
Sending response
done

Socket#0:0x22 8888 D:198.55.111.50(123)
Socket#1:0x0 80 D:192.168.1.254(3725)
Socket#2:0x17 80 D:192.168.1.254(3726)
Socket#3:0x14 80 D:192.168.1.254(3724)
Unix time = 1366996132
Client request: GET /favicon.ico HTTP/1.1

POST data:
Sending response
done

edit: Removed my NTP server ip.
« Last Edit: April 26, 2013, 12:26:04 pm by SurferTim » Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I guess I don't understand how your UDP connection got setup on socket 0 and the TCP listening socket is on socket 1?  In the code it calls server.begin() before we've done anything with UDP, so that should use socket 0, and the first showSockStatus() gets called before we've ever done anything with UDP, but your first message shows a UDP socket listening on port 8888 as socket 0.  My first message looks like this:

Quote
Start!
Socket#0:0x14 80 D:0.0.0.0(0)
Socket#1:0x0 0 D:0.0.0.0(0)
Socket#2:0x0 0 D:0.0.0.0(0)
Socket#3:0x0 0 D:0.0.0.0(0)
 
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Here is yours:
Code:
void setup() {
Serial.begin(9600);
Ethernet.begin(mac, ip, INADDR_NONE, gateway, subnet);
delay(500);

Serial.println("Start!");
// here is where the first socket is assigned:
server.begin();
ShowSockStatus();
timer = millis();
}

Here is mine:
Code:
void setup() {
Serial.begin(9600);

        pinMode(4, OUTPUT);
        digitalWrite(4, HIGH);
       
Ethernet.begin(mac, ip, INADDR_NONE, gateway, subnet);
delay(500);

// here is socket #0
Udp.begin(8888);

Serial.println("Start!");

// here is socket #1
server.begin();
ShowSockStatus();
timer = millis();
}
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

OK.  I see now why yours is working.  You dedicate a socket to the UDP connection that never is freed.  So you never reuse a socket that was previously used as a UDP socket as a TCP socket and vice versa.  Thus you avoid the issue.  In my version the call to CheckTime will create the UDP socket and then tear it down, freeing the  socket for use by other clients. 

What you've got is a workaround for the problem I'm having, but the problem I'm having is still a bug.  The W5100 only has 4 sockets available, and dedicating one of them full time to an NTP client when you only need to use that socket once every few days, and you only need it for about 500ms can be wasteful.  Creating the UDP socket and tearing it down should be a reasonable scenario, but it doesn't work.
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

You have 4 sockets. Use them wisely. I like the full time UDP socket, and would like to reserve a socket for client stuff when a server is running. Here is my opinion:
http://arduino.cc/forum/index.php/topic,159138.msg1210212.html#msg1210212
Note my sketch uses all the sockets. One (socket#0) for UDP, and the rest (#1-3) for the server.
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

It sounds like this guy is having exactly the same problem as I am, but he doesn't know it.  He thinks he's running out of sockets, but in actuality the issue is a bug somewhere that won't allow you to reuse a socket that was previously allocated as a TCP socket as a UDP socket.

Your workaround is find for many scenarios, but not mine.  I'm trying to build a simple web server.  One that syncs time via UDP periodically and also includes a TFTP server so you can upload content to the SD card.  TFTP uses 1 UDP socket for the server, and one for the client if it connects.  So, to avoid the bug that I've identified here, I'd have to dedicate one socket to the NTP client, one socket to the TFTP server, one socket to the TFTP client, and then I'd have one remaining socket to use as a my listening socket for HTTP.  Of course that means I don't have a socket to use if someone actually connected to my HTTP server.

In other words, I'm sunk unless I can figure out how to resolve this bug. (or upgrade to the 5200, which seems like a waste)

Incidentally, another workaround is to actually reinitialize the W5100 after every TCP client disconnects.  (i.e. call Ethernet.begin() again)  Of course that means you will also have to go reattach your HTTP server and UDP servers.  Super kludgy, but it may be the only way around this bug.
Logged

Miramar Beach, Florida
Offline Offline
Faraday Member
**
Karma: 138
Posts: 5843
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

That one UDP socket will work for every UDP function, like dhcp, ntp, dns, etc...all use that socket. One socket, all that stuff is covered. smiley

I know when I am having a problem, but this isn't it. If this was an Apache server, I would expect more.

I will give you the benefit of the doubt, and try to begin and stop a UDP socket and see how it affects the server and the UDP sockets. I'm not sure why I would do that, and I don't really expect it to work. You are assuming that you will need all the sockets for the server simultaneously at times, which would guarantee a NTP fail in that time.
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 25
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

You actually bring up a fantastic point with your DNS example.   When you call EthernetClient::connect(char * host, uint8_t port), it does exactly what I do with NTP.  It dynamically creates a UDP socket for DNS, connects to a server, and then releases that socket.  That should work just fine, except that this bug exists.  I'm certain that I can create a scenario with a http server that has a few connects() in it that will start failing on DNS resolution because of the bug.  There would be no solution either, because you can't manually specify a socket for the DNS server to use.  It just dynamically allocates one from the unused pool.
Logged

Pages: [1] 2 3   Go Up
Jump to: