答案是特定于实现的。您需要检查操作系统上的 tcp 实现头文件。这是一个返回套接字状态的 linux 示例客户端。
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}"
这是我最新的 ubuntu linux 的 tcp_info 结构
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;
};
您可能会注意到我的脚本只返回一个整数。这是详细说明 TCP 状态及其整数值的 C 枚举。同样,这是在 /usr/include/netinet/tcp.h 中找到的
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 */
};
此外,该线程说您可以通过读取 EOF 来检测 CLOSE_WAIT。但由于您担心数据是否已发送,您可能需要解压到 tcpi_last_data_sent。
最后,一个警告。我接受了回答你的问题的挑战,因为它听起来很有趣,但我的 C 腿仍然摇摆不定,所以 YMMV。:)