1

我正在尝试通信服务器 SSL 套接字 Java 和客户端 SSL 套接字 Python。发送的第一条消息是可以的,但是当服务器发送另一条消息时,客户端会收到分成两部分的消息。例如:如果服务器发送消息“abcdefghij”,客户端首先收到“a”,然后是“bcdefghij”。

有人知道为什么在第一次收到消息后分为两部分?问候。

客户端代码:

import socket, ssl, pprint
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
ssl_sock = ssl.wrap_socket(s, ssl_version=ssl.PROTOCOL_TLSv1, cert_reqs=ssl.CERT_NONE)
ssl_sock.connect(('localhost', 7000))
pprint.pprint(ssl_sock.getpeercert())

while(1):
    print "Waiting"
    data = ssl_sock.recv()  
    print "Received:", data
    data = ""

ssl_sock.close()

服务器代码:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.security.KeyStore;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLServerSocket;
import javax.net.ssl.SSLServerSocketFactory;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;


public class SslReverseEchoer {

    public static void main(String[] args) {
        char ksPass[] = "123456".toCharArray();
        char ctPass[] = "123456".toCharArray();

        try {
            KeyStore ks = KeyStore.getInstance("JKS");
            ks.load(new FileInputStream("keystore.jks"), ksPass);
            KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
            kmf.init(ks, ctPass);
            SSLContext sc = SSLContext.getInstance("TLS");
            sc.init(kmf.getKeyManagers(), null, null);
            SSLServerSocketFactory ssf = sc.getServerSocketFactory();
            SSLServerSocket s = (SSLServerSocket) ssf.createServerSocket(7000);
            printServerSocketInfo(s);
            SSLSocket c = (SSLSocket) s.accept();
            printSocketInfo(c);
            BufferedWriter w = new BufferedWriter(new OutputStreamWriter(c.getOutputStream()));
            BufferedReader r = new BufferedReader(new InputStreamReader(c.getInputStream()));
            //1th time
            String m = "abcdefghj1234567890";
            w.write(m, 0, m.length());
            w.newLine();
            w.flush();
            //2th time
            String m2 = "#abcdefghj1234567890";
            w.write(m2, 0, m2.length());
            w.newLine();
            w.flush();
            //3th time
            String m3 = "?abcdefghj1234567890";
            w.write(m3, 0, m3.length());
            w.newLine();
            w.flush();
            while ((m = r.readLine()) != null) {
                if (m.equals("."))
                    break;
                char[] a = m.toCharArray();
                int n = a.length;
                for (int i = 0; i < n / 2; i++) {
                    char t = a[i];
                    a[i] = a[n - 1 - i];
                    a[n - i - 1] = t;
                }
                w.write(a, 0, n);
                w.newLine();
                w.flush();
            }
            w.close();
            r.close();
            c.close();
            s.close();
        } catch (Exception e) {
            System.err.println(e.toString());
        }
    }

    private static void printSocketInfo(SSLSocket s) {
        System.out.println("Socket class: " + s.getClass());
        System.out.println("   Remote address = " + s.getInetAddress().toString());
        System.out.println("   Remote port = " + s.getPort());
        System.out.println("   Local socket address = " + s.getLocalSocketAddress().toString());
        System.out.println("   Local address = " + s.getLocalAddress().toString());
        System.out.println("   Local port = " + s.getLocalPort());
        System.out.println("   Need client authentication = " + s.getNeedClientAuth());
        SSLSession ss = s.getSession();
        System.out.println("   Cipher suite = " + ss.getCipherSuite());
        System.out.println("   Protocol = " + ss.getProtocol());
    }

    private static void printServerSocketInfo(SSLServerSocket s) {
        System.out.println("Server socket class: " + s.getClass());
        System.out.println("   Socker address = " + s.getInetAddress().toString());
        System.out.println("   Socker port = " + s.getLocalPort());
        System.out.println("   Need client authentication = " + s.getNeedClientAuth());
        System.out.println("   Want client authentication = " + s.getWantClientAuth());
        System.out.println("   Use client mode = " + s.getUseClientMode());
    }
}
4

3 回答 3

2

似乎您希望始终能够从另一侧读取您在一个块中发送的任何数量的数据。

这是一个常见错误,并非特定于 SSL/TLS,也与普通 TCP 通信有关。

您应该始终循环并阅读您打算阅读的任何内容。您还应该定义您的协议(或使用现有协议)以考虑命令和请求/响应终止符。

例如,HTTP 使用空行来告诉标头的结尾,而标Content-Length头或分块传输编码来告诉接收者何时停止读取正文。

SMTP 使用以行分隔的命令和一个.用于消息结尾的命令。

于 2012-08-03T00:19:20.600 回答
1

它是服务器端的 Naggle 算法和客户端 TCP 堆栈中的延迟 ACK 的组合。您还会发现两个数据包之间的延迟约为 40 毫秒。

在服务器端禁用 Naggle 算法以进行补救:

SSLSocket c = (SSLSocket) s.accept();
c.setTcpNoDelay(true);

关于为什么会在这里发生的更多信息:http: //www.stuartcheshire.org/papers/NagleDelayedAck/

编辑添加:注意下面布鲁诺的回答。虽然这描述了您在此处看到的具体原因,但不能保证您期望来自服务器的数据的方式。

于 2012-08-03T00:07:33.800 回答
0

我尝试通过两种方式解决我的问题,消息总是在第一个字符处中断,所以我决定在每条消息的开头和结尾添加三个空格。因此,当客户收到它们时,请对消息进行修剪。我发现的另一种方法是使用 DataOutputStream,该方法逐字节传递 writeBytes,在服务器上使用它,客户端在接收数据时发生 q 变化,消息必须构建客户端处理才能最终完成我想要的内容消息的结尾。感谢您的讨论!

于 2012-08-04T01:23:46.477 回答