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Building OpenSSL on Android NDK

由 六月ゝ 毕业季﹏ 提交于 2019-12-04 11:15:58
问题 I want to use DTLS (on OpenSSL) using JNI on Android 2.1/2.2. Can someone help me get started (tutorials, howto, pointers etc) with building OpenSSL for Android (2.1/2.2) using the Android NDK? Anything important that I should be aware of before doing it. Thanks. 回答1: I guess you don't need help with basic building of programs and OpenSSL. For specifics of Android and OpenSSL, take a look at Fries's GitHub repository called android-external-openssl. Take a look especially at README located

Non-blocking UDP I/O vs blocking UDP I/O in Java

由 旧时模样 提交于 2019-12-04 08:21:21
问题 Non-blocking TCP/IP SocketChannel s and Selector in NIO help me to handle many TCP/IP connections with small number of threads. But how about UDP DatagramChannels ? (I must admit that I'm not very familiar with UDP.) UDP send operations don't seem to block even if the DatagramChannel is not operating in blocking mode. Is there really a case where DatagramSocket.send(DatagramPacket) blocks due to congestion or something similar? I'm really curious if there's such a case and what the possible

Message sent in UDP datagram is not sanitized?

由 落花浮王杯 提交于 2019-12-04 06:23:53
问题 My code is as follows. Everything works the way I want it to, but when my messages are received they have many boxes on the end somewhat like this like this "Message: hello▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀" How can I make it so what is received and printed is only "Message: hello"? I greatly appreciate any help. import java.io.*; import java.net.*; public class UDPChat { public static void main(String args[]) throws Exception { new UDPChat(); } public UDPChat() { try { runChat(); } catch (Exception

How to make two-directional unix domain sockets with SOCK_DGRAM?

由 走远了吗. 提交于 2019-12-04 03:58:22
问题 I am trying to write a simple Unix datagram server/client, and am having some problems. What I want is a server that listens on a datagram socket and sends a reply to every message received, to the original sender. I decided to try first using socat to be the "server" and writing the client in C. I am running socat like this: socat UNIX-DGRAM:/tmp/test.socket,fork EXEC:echo To the best of my understanding this should listen on /tmp/test.socket and reply to everything that is received with the

Why is Netty giving me only 768 Bytes from UDP messages

由 拟墨画扇 提交于 2019-12-03 16:04:58
I have set the "receiveBufferSize" option to 1024, but for some reason I'm still getting only 768 bytes in messageReceived. The header of the data indicates that size of the data being sent is 1004. Below is the initialization code for the server: public static void main(String[] args) throws Exception { ConnectionlessBootstrap b = new ConnectionlessBootstrap(new NioDatagramChannelFactory()); // Options for a new channel b.setOption("receiveBufferSize", 1024); System.out.println(b.getOptions()); b.setPipelineFactory(new ChannelPipelineFactory() { @Override public ChannelPipeline getPipeline()

What's the difference between streams and datagrams in network programming?

由 三世轮回 提交于 2019-12-03 00:02:41
问题 What's the difference between sockets (stream) vs sockets (datagrams)? Why use one over the other? 回答1: A long time ago I read a great analogy for explaining the difference between the two. I don't remember where I read it so unfortunately I can't credit the author for the idea, but I've also added a lot of my own knowledge to the core analogy anyway. So here goes: A stream socket is like a phone call -- one side places the call, the other answers, you say hello to each other (SYN/ACK in TCP)

Non-blocking UDP I/O vs blocking UDP I/O in Java

由 ╄→гoц情女王★ 提交于 2019-12-02 22:40:48
Non-blocking TCP/IP SocketChannel s and Selector in NIO help me to handle many TCP/IP connections with small number of threads. But how about UDP DatagramChannels ? (I must admit that I'm not very familiar with UDP.) UDP send operations don't seem to block even if the DatagramChannel is not operating in blocking mode. Is there really a case where DatagramSocket.send(DatagramPacket) blocks due to congestion or something similar? I'm really curious if there's such a case and what the possible cases exist in a production environment. If DatagramSocket.send(DatagramPacket) doesn't actually block

What's the difference between streams and datagrams in network programming?

由 不想你离开。 提交于 2019-12-02 13:47:25
What's the difference between sockets (stream) vs sockets (datagrams)? Why use one over the other? A long time ago I read a great analogy for explaining the difference between the two. I don't remember where I read it so unfortunately I can't credit the author for the idea, but I've also added a lot of my own knowledge to the core analogy anyway. So here goes: A stream socket is like a phone call -- one side places the call, the other answers, you say hello to each other (SYN/ACK in TCP), and then you exchange information. Once you are done, you say goodbye (FIN/ACK in TCP). If one side doesn

LuaSocket (UDP) not receiving datagrams

由 跟風遠走 提交于 2019-12-02 05:25:00
问题 I'm experimenting with LuaSocket for a project I'm working on. I've chosen UDP as my protocol. Looking for docs and tutorials online, I've attempted to create a client-server pair for testing and learning. According to what I've read, the following code should work. However, only the server seems to be working properly. The client sends a message, but it will not receive the reply from the server. Thank you for any help anyone can provide. Server: -- Server #!/usr/bin/env lua5.1 local socket

UWP DatagramSocket Multicast

由 心已入冬 提交于 2019-12-02 03:12:49
问题 I managed to make a simple application that sends and receives data from a multicast group. If I open 2 instance of the application (2 different .sln files with the same code) I can send and receive data. The problem is that after 5 seconds, if I send a message from the Client001 only the Client001 will get the message. But, if I send message from the Client002 (the second instance of the app) within the 5 seconds then both of them get the message. I had an example with UdpClient that was
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