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Is it possible to find out if the ruby ​​socket is in the ESTABLISHED or CLOSE_WAIT state without actually sending or reading data?

s = Socket.new(Socket::AF_INET, Socket::SOCK_STREAM, 0)
s.connect(Socket.pack_sockaddr_in('port', 'hostname'))

ssl = OpenSSL::SSL::SSLSocket.new(s, sslcert)
ssl.connect

Here I would like to check the stream if the ssl connection and the underlying socket are still ESTABLISHED, or if it went in CLOSE_WAITafter the default was 7200 seconds or even worse closed, without actually needing .write()or .read().

Is this done using select(), IO.select()or another method?

BTW: the socket never receives any data that it just sends sometimes.

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. tcp . linux, .

  ts = TCPSocket.new('localhost', 5777)
  ssl = OpenSSL::SSL::SSLSocket.new(ts, OpenSSL::SSL::SSLContext.new)
  ssl.sync = true
  ssl.connect
  # TCP_INFO is 11
  # note that TCP_INFO isn't defined in the ruby source.  
  # i had to look up the integer value in /usr/include/netinet/tcp.h
  optval = ts.getsockopt(Socket::SOL_TCP, 11) 
  state = optval.unpack "i" 
  puts "state: #{state}"

tcp_info ubuntu linux

struct tcp_info
{
  u_int8_t      tcpi_state;
  u_int8_t      tcpi_ca_state;
  u_int8_t      tcpi_retransmits;
  u_int8_t      tcpi_probes;
  u_int8_t      tcpi_backoff;
  u_int8_t      tcpi_options;
  u_int8_t      tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;

  u_int32_t     tcpi_rto;
  u_int32_t     tcpi_ato;
  u_int32_t     tcpi_snd_mss;
  u_int32_t     tcpi_rcv_mss;

  u_int32_t     tcpi_unacked;
  u_int32_t     tcpi_sacked;
  u_int32_t     tcpi_lost;
  u_int32_t     tcpi_retrans;
  u_int32_t     tcpi_fackets;

  /* Times. */
  u_int32_t     tcpi_last_data_sent;
  u_int32_t     tcpi_last_ack_sent;     /* Not remembered, sorry.  */
  u_int32_t     tcpi_last_data_recv;
  u_int32_t     tcpi_last_ack_recv;

  /* Metrics. */
  u_int32_t     tcpi_pmtu;
  u_int32_t     tcpi_rcv_ssthresh;
  u_int32_t     tcpi_rtt;
  u_int32_t     tcpi_rttvar;
  u_int32_t     tcpi_snd_ssthresh;
  u_int32_t     tcpi_snd_cwnd;
  u_int32_t     tcpi_advmss;
  u_int32_t     tcpi_reordering;

  u_int32_t     tcpi_rcv_rtt;
  u_int32_t     tcpi_rcv_space;

  u_int32_t     tcpi_total_retrans;
};

, script . C, TCP . , /usr/include/netinet/tcp.h

enum
{   
  TCP_ESTABLISHED = 1,          
  TCP_SYN_SENT,
  TCP_SYN_RECV,
  TCP_FIN_WAIT1,
  TCP_FIN_WAIT2,
  TCP_TIME_WAIT,
  TCP_CLOSE,
  TCP_CLOSE_WAIT,
  TCP_LAST_ACK,
  TCP_LISTEN, 
  TCP_CLOSING   /* now a valid state */
};

, , CLOSE_WAIT, EOF. , , , , tcpi_last_data_sent.

, . , , C , YMMV.:)

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