[编织消息框架][传输协议]sctp简单开发

jdk1.7支持sctp协议，需要linux安装sctp支持库

测试代码

 public class ServerSCTP {
     static int SERVER_PORT = 3456;
     static int US_STREAM = 0;
     static int FR_STREAM = 1;
 
     static SimpleDateFormat USformatter = new SimpleDateFormat("h:mm:ss a EEE d MMM yy, zzzz", Locale.US);
     static SimpleDateFormat FRformatter = new SimpleDateFormat("h:mm:ss a EEE d MMM yy, zzzz", Locale.FRENCH);
 
     @SuppressWarnings("restriction")
     public static void main(String[] args) throws IOException {
         com.sun.nio.sctp.SctpServerChannel ssc = com.sun.nio.sctp.SctpServerChannel.open();
         ssc.bind(new InetSocketAddress(SERVER_PORT));
 
         ByteBuffer buf = ByteBuffer.allocateDirect(60);
         CharBuffer cbuf = CharBuffer.allocate(60);
         CharsetEncoder encoder = Charset.forName("ISO-8859-1").newEncoder();
 
         while (true) {
             com.sun.nio.sctp.SctpChannel sc = ssc.accept();
 
             /* get the current date */
             Date today = new Date();
             cbuf.put(USformatter.format(today)).flip();
             encoder.encode(cbuf, buf, true);
             buf.flip();
 
             /* send the message on the US stream */
             com.sun.nio.sctp.MessageInfo messageInfo = com.sun.nio.sctp.MessageInfo.createOutgoing(null, US_STREAM);
             sc.send(buf, messageInfo);
 
             /* update the buffer with French format */
             cbuf.clear();
             cbuf.put(FRformatter.format(today)).flip();
             buf.clear();
             encoder.encode(cbuf, buf, true);
             buf.flip();
 
             /* send the message on the French stream */
             messageInfo.streamNumber(FR_STREAM);
             sc.send(buf, messageInfo);
 
             cbuf.clear();
             buf.clear();
 
             sc.close();
         }
     }
 }

 @SuppressWarnings("restriction")
 public class ClientSCTP {
     static int SERVER_PORT = 3456;
     public void run() throws IOException {
         ByteBuffer buf = ByteBuffer.allocateDirect(60);
         Charset charset = Charset.forName("ISO-8859-1");
         CharsetDecoder decoder = charset.newDecoder();
 
         com.sun.nio.sctp.SctpChannel sc = com.sun.nio.sctp.SctpChannel.open(new InetSocketAddress("localhost", SERVER_PORT), 0, 0);
 
         /* handler to keep track of association setup and termination */
         AssociationHandler assocHandler = new AssociationHandler();
         /* expect two messages and two notifications */
         com.sun.nio.sctp.MessageInfo messageInfo = null;
         do {
             messageInfo = sc.receive(buf, System.out, assocHandler);
             buf.flip();
 
             if (buf.remaining() > 0 && messageInfo.streamNumber() == ServerSCTP.US_STREAM) {
 
             System.out.println("(US) " + decoder.decode(buf).toString());
             } else if (buf.remaining() > 0 && messageInfo.streamNumber() == ServerSCTP.FR_STREAM) {
             System.out.println("(FR) " + decoder.decode(buf).toString());
             }
             buf.clear();
         } while (messageInfo != null);
 
         sc.close();
     }
 
     public static void main(String[] args) throws IOException {
         new ClientSCTP().run();
     }
 
     static class AssociationHandler extends com.sun.nio.sctp.AbstractNotificationHandler<PrintStream> {
         public com.sun.nio.sctp.HandlerResult handleNotification(com.sun.nio.sctp.AssociationChangeNotification not, PrintStream stream) {
             if (not.event().equals(com.sun.nio.sctp.AssociationChangeNotification.AssocChangeEvent.COMM_UP)) {
                 int outbound = not.association().maxOutboundStreams();
                 int inbound = not.association().maxInboundStreams();
                 stream.printf("New association setup with %d outbound streams" + ", and %d inbound streams.\n", outbound, inbound);
             }
 
             return com.sun.nio.sctp.HandlerResult.CONTINUE;
         }
 
         public com.sun.nio.sctp.HandlerResult handleNotification(com.sun.nio.sctp.ShutdownNotification not, PrintStream stream) {
             stream.printf("The association has been shutdown.\n");
             return com.sun.nio.sctp.HandlerResult.RETURN;
         }
     }
 }

导出ClientSCTP.class,ServerSCTP.class

环境部署

1.linux检查是否支持sctp，官方提示必须内核2.6版本以上，有信息显示代表已安装

lsmod | grep sctp

1.1如果没有就下载

官方：http://lksctp.sourceforge.net/

github:https://github.com/sctp/lksctp-tools

tar -zxf lksctp-tools-1.0..tar.gz
 
cd lksctp-tools-1.0.
 
./configure
 
make
 
make install

2.执行  ./java8.sh -jar testsctp.jar 抛异常

java.lang.UnsupportedOperationException: libsctp.so.1: cannot open shared object file: No such file or directory

原因是没有配置 $LD_LIBRARY_PATH 环境变量

echo $LD_LIBRARY_PATH
export LD_LIBRARY_PATH=/usr/local/lib

继续执行 ./java8.sh -jar testsctp.jar 还是抛异常

java.net.SocketException: Protocol not supported

原因是系统没有加载lksctp模块

modprobe sctp
 
lsmod |grep sctp

再执行出现连接异常

java.net.SocketException: Permission denied

原因是linux selinux 安全限制，解决方式临时关闭

setenforce 0

永久关闭

ehco "SELINUX=disabled" >> /etc/selinux/config

本人测试：连接60000client没aio快，原因是sctp建立链接要求四次握手