I've been setting up wireguard-go on an old Linux kernel (no module), and hit a bug with ipv6-less kernels. The create6() function returns 0 as the port number when an error occurs, so even though CreateBind checks for EAFNOSUPPORT, it still ends up with port getting set to zero, resulting in a random port.
I solved it by returning port instead of zero - as far as I can see this shouldn't break anything, as CreateBind will return 0 anyway on errors other than EAFNOSUPPORT. I did not check whether the same bug exists in conn_default.go - Kent --- conn_linux.go.old 2018-09-05 23:11:19.407372785 +0200 +++ conn_linux.go 2018-09-07 16:58:28.971914271 +0200 @@ -335,7 +335,7 @@ ) if err != nil { - return -1, 0, err + return -1, port, err } addr := unix.SockaddrInet4{ @@ -366,7 +366,7 @@ return unix.Bind(fd, &addr) }(); err != nil { unix.Close(fd) - return -1, 0, err + return -1, port, err } return fd, uint16(addr.Port), err @@ -383,7 +383,7 @@ ) if err != nil { - return -1, 0, err + return -1, port, err } // set sockopts and bind @@ -425,7 +425,7 @@ }(); err != nil { unix.Close(fd) - return -1, 0, err + return -1, port, err } return fd, uint16(addr.Port), err _______________________________________________ WireGuard mailing list WireGuard@lists.zx2c4.com https://lists.zx2c4.com/mailman/listinfo/wireguard