DualModeAcceptAsync.AcceptAsyncV6BoundToAnyV4_CantConnect failed in CI

[stephentoub]

https://ci.dot.net/job/dotnet_corefx/job/master/job/ubuntu14.04_release_prtest/2476/consoleText

System.Net.Sockets.Tests.DualModeAcceptAsync.AcceptAsyncV6BoundToAnyV4_CantConnect [FAIL]
        Assert.Throws() Failure
        Expected: typeof(System.Net.Sockets.SocketException)
        Actual:   typeof(System.TimeoutException): Timed out while waiting for the server accept...
        Stack Trace:
           /mnt/j/workspace/dotnet_corefx/master/ubuntu14.04_release_prtest/src/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs(976,0): at System.Net.Sockets.Tests.DualModeAcceptAsync.DualModeConnect_AcceptAsync_Helper(IPAddress listenOn, IPAddress connectTo)

[davidsh]

I will disable the test for now.

[steveharter]

Fix is to disable such tests on non-Windows. Loopback IPV4 and Loopback IPV6 considered separate addresses and on Linux it is easy to get both to exist as separate connections with same port.

[AriNuer]

Test System.Net.Sockets.Tests.DualModeAcceptAsync.AcceptAsyncV6BoundToAnyV4_CantConnect failed with similar exception:

    System.Net.Sockets.Tests.DualModeAcceptAsync.AcceptAsyncV6BoundToAnyV4_CantConnect [FAIL]
      Assert.Throws() Failure
      Expected: typeof(System.Net.Sockets.SocketException)
      Actual:   typeof(System.TimeoutException): Timed out while waiting for either of client and server connections...
      ---- System.TimeoutException : Timed out while waiting for either of client and server connections...
      Stack Trace:
        /_/src/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs(973,0): at System.Net.Sockets.Tests.DualModeAcceptAsync.DualModeConnect_AcceptAsync_Helper(IPAddress listenOn, IPAddress connectTo)
        /_/src/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs(934,0): at System.Net.Sockets.Tests.DualModeAcceptAsync.<AcceptAsyncV6BoundToAnyV4_CantConnect>b__6_0()
        ----- Inner Stack Trace -----
        /_/src/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs(973,0): at System.Net.Sockets.Tests.DualModeAcceptAsync.DualModeConnect_AcceptAsync_Helper(IPAddress listenOn, IPAddress connectTo)
        /_/src/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs(934,0): at System.Net.Sockets.Tests.DualModeAcceptAsync.<AcceptAsyncV6BoundToAnyV4_CantConnect>b__6_0()
  Finished:    System.Net.Sockets.Tests
=== TEST EXECUTION SUMMARY ===
   System.Net.Sockets.Tests  Total: 958, Errors: 0, Failed: 1, Skipped: 9, Time: 65.515s
----- end Fri 08/16/2019  6:50:00.96 ----- exit code 1 ----------------------------------------------------------

Build: -20190815(Master)

Details:
https://helix.dot.net/api/2019-06-17/jobs/ca00932e-ead4-406d-8275-a9eb70421e41/workitems/System.Net.Sockets.Tests/console

[ViktorHofer]

Failed again on netcoreapp-Windows_NT-Release-x86-Windows.10.Amd64.Client19H1.Open : https://dnceng.visualstudio.com/public/_build/results?buildId=312794&view=ms.vss-test-web.build-test-results-tab&runId=9031242&paneView=debug&resultId=169615

[steveharter]

FWIW I dug up my old POSIX repro that shows port collisions are possible across protocols; this should only repro on Unix although with enough iterations to cycle around past 65,535 could also occur on Windows (haven't verified).

It asks for a port using Ipv6 and then loops 10,000 times to see if the same port number can be assigned for Ipv4.

Not tested here but you can have both UDP vs TCP on same protocol (IPV4) using the same port, meaning collisions are possible that way too.

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/socket.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>

static int CreateIpv4Socket(bool closeSocket, int portToUse)
{
       struct sockaddr_in serv_addr;

       int sockfd = socket(AF_INET, SOCK_STREAM, 0);
       if (sockfd < 0)
       {
              perror("ERROR opening socket");
              exit(1);
       }

       bzero((char *)&serv_addr, sizeof(serv_addr));

       serv_addr.sin_family = AF_INET;
       serv_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
       if (portToUse == 0)
       {
              serv_addr.sin_port = 0;
       }
       else
       {
              serv_addr.sin_port = htons(portToUse);
       }

       if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
              perror("ERROR on binding");
              exit(1);
       }

       struct sockaddr_in out_addr;
       socklen_t len = sizeof(out_addr);
       if (getsockname(sockfd, (struct sockaddr *)&out_addr, &len) == -1) {
              perror("getsockname");
              exit(1);
       }

       int portUsed = out_addr.sin_port;

       if (closeSocket)
              close(sockfd);

       return portUsed;
}

static int CreateIpv6Socket(bool closeSocket, int portToUse)
{
       struct sockaddr_in6 serv_addr;

       int sockfd = socket(AF_INET6, SOCK_STREAM, 0);
       if (sockfd < 0)
       {
              perror("ERROR opening socket2");
              exit(1);
       }

       bzero((char *)&serv_addr, sizeof(serv_addr));

       serv_addr.sin6_family = AF_INET6;
       serv_addr.sin6_addr = in6addr_loopback;
       if (portToUse == 0)
       {
              serv_addr.sin6_port = 0;
       }
       else
       {
              serv_addr.sin6_port = htons(portToUse);
       }

       if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
       {
              perror("ERROR on binding2");
              exit(1);
       }

       struct sockaddr_in6 addr_in6;
       socklen_t len2 = sizeof(addr_in6);
       if (getsockname(sockfd, (struct sockaddr *)&addr_in6, &len2) == -1)
       {
              perror("getsockname2");
              exit(1);
       }

       int portUsed = addr_in6.sin6_port;

       if (closeSocket)
              close(sockfd);

       return portUsed;
}

int main(int argc, char *argv[])
{
       int port = CreateIpv6Socket(false, 0);
       for (int i = 0; i < 10000; i++)
       {
              int port2 = CreateIpv4Socket(true, 0);
              printf("count: %d\tport number %d\t; original:%d\n", i, ntohs(port2), ntohs(port));

              if (port == port2)
              {
                     perror("DUPLICATE SOCKET. STOPPING");
                     exit(1);
              }
       }

       return 0;
}

[antonfirsov]

No recent Windows failures, stabilization & re-enabling is covered by #1481.