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--- sk2:sockets_templates [2015/10/14 12:02]
jkonczak
+++ sk2:sockets_templates [2016/11/08 16:19] (aktualna)
jkonczak nowe szablony
@@ Linia 1: / Linia 1: @@
-====== Basic ======
+====== Klient TCP odbierz - wyślij ======
+<code cpp tcp_client_template.cpp>
+#include <cstdlib>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <errno.h>
+#include <error.h>
+#include <netdb.h>
+#include <sys/epoll.h>
+#include <poll.h>
+#include <thread>
-<code cpp basic.cpp>
+ssize_t readData(int fd, char * buffer, ssize_t buffsize){
-#include <iostream>                 //    ____                _                  _        _      __                  __
+	auto ret = read(fd, buffer, buffsize);
-#include <sys/socket.h>             //   |  _ \ ___  __ _  __| |  ___  ___   ___| | _____| |_   / / __ ___  _____   _\ \.
+	if(ret==-1) error(1,errno, "read failed on descriptor %d", fd);
-#include <netinet/in.h>             //   | |_) / _ \/ _` |/ _` | / __|/ _ \ / __| |/ / _ \ __| | | '__/ _ \/ __\ \ / /| |
+	return ret;
-#include <arpa/inet.h>              //   |  _ <  __/ (_| | (_| | \__ \ (_) | (__|   <  __/ |_  | | | |  __/ (__ \ V / | |
+}
-#include <unistd.h>                 //   |_| \_\___|\__,_|\__,_| |___/\___/ \___|_|\_\___|\__| | |_|  \___|\___| \_/  | |
-                                    //                                                          \_\                  /_/
+void writeData(int fd, char * buffer, ssize_t count){
-int main(int argc, char **argv) {
+	auto ret = write(fd, buffer, count);
+	if(ret==-1) error(1, errno, "write failed on descriptor %d", fd);
+	if(ret!=count) error(0, errno, "wrote less than requested to descriptor %d (%ld/%ld)", fd, count, ret);
+}
+int main(int argc, char ** argv){
+	if(argc!=3) error(1,0,"Need 2 args");
-	int fd = socket(PF_INET, SOCK_STREAM, 0);
+	// Resolve arguments to IPv4 address with a port number
+	addrinfo *resolved, hints={.ai_flags=0, .ai_family=AF_INET, .ai_socktype=SOCK_STREAM};
+	int res = getaddrinfo(argv[1], argv[2], &hints, &resolved);
+	if(res || !resolved) error(1, errno, "getaddrinfo");
-	sockaddr_in address { .sin_family = AF_INET,
+	// create socket
-	                      .sin_port = htons(13),
+	int sock = socket(resolved->ai_family, resolved->ai_socktype, 0);
-	                      .sin_addr = {.s_addr = inet_addr("127.0.0.1") }
+	if(sock == -1) error(1, errno, "socket failed");
-	                    };
-	connect(fd, (sockaddr*) &address, sizeof(address));
+	// attept to connect
+	res = connect(sock, resolved->ai_addr, resolved->ai_addrlen);
+	if(res) error(1, errno, "connect failed");
-	char buffer[255];
+	// free memory
+	freeaddrinfo(resolved);
-	ssize_t readSize = recv(fd, buffer, 254, 0);
+/****************************/
-	buffer[readSize] = 0;
+	// read from socket, write to stdout
+	ssize_t bufsize1 = 255, received1;
+	char buffer1[bufsize1];
+	received1 = readData(sock, buffer1, bufsize1);
+	writeData(1, buffer1, received1);
-	close(fd);
+/****************************/
-	std::cout << buffer << std::endl;
+	// read from stdin, write to socket
+	ssize_t bufsize2 = 255, received2;
+	char buffer2[bufsize2];
+	received2 = readData(0, buffer2, bufsize2);
+	writeData(sock, buffer2, received2);
+/****************************/
+	close(sock);
 	return 0;
@@ Linia 33: / Linia 67: @@
 </code>
-====== Klient TCP ======
+====== Serwer TCP połącz - wyślij do wszystkich ======
+<code cpp tcp_server_template.cpp>
+#include <cstdlib>
+#include <cstdio>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <netdb.h>
+#include <sys/epoll.h>
+#include <poll.h>
+#include <thread>
+#include <unordered_set>
+#include <signal.h>
+// server socket
+int servFd;
+// client sockets
+std::unordered_set<int> clientFds;
+// handles SIGINT
+void ctrl_c(int);
+// sends data to clientFds excluding fd
+void sendToAllBut(int fd, char * buffer, int count);
+// converts cstring to port
+uint16_t readPort(char * txt);
+// sets SO_REUSEADDR
+void setReuseAddr(int sock);
+int main(int argc, char ** argv){
+	// get and validate port number
+	if(argc != 2) error(1, 0, "Need 1 arg (port)");
+	auto port = readPort(argv[1]);
+	// create socket
+	servFd = socket(AF_INET, SOCK_STREAM, 0);
+	if(servFd == -1) error(1, errno, "socket failed");
+	// graceful ctrl+c exit
+	signal(SIGINT, ctrl_c);
+	// prevent dead sockets from throwing pipe errors on write
+	signal(SIGPIPE, SIG_IGN);
+	setReuseAddr(servFd);
+	// bind to any address and port provided in arguments
+	sockaddr_in serverAddr{.sin_family=AF_INET, .sin_port=htons((short)port), .sin_addr={INADDR_ANY}};
+	int res = bind(servFd, (sockaddr*) &serverAddr, sizeof(serverAddr));
+	if(res) error(1, errno, "bind failed");
+	// enter listening mode
+	res = listen(servFd, 1);
+	if(res) error(1, errno, "listen failed");
+/****************************/
+	while(true){
+		// prepare placeholders for client address
+		sockaddr_in clientAddr{0};
+		socklen_t clientAddrSize = sizeof(clientAddr);
+		// accept new connection
+		auto clientFd = accept(servFd, (sockaddr*) &clientAddr, &clientAddrSize);
+		if(clientFd == -1) error(1, errno, "accept failed");
+		// add client to all clients set
+		clientFds.insert(clientFd);
+		// tell who has connected
+		printf("new connection from: %s:%hu (fd: %d)\n", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port), clientFd);
+/****************************/
+		// read a message
+		char buffer[255];
+		int count = read(clientFd, buffer, 255);
+		if(count < 1) {
+			printf("removing %d\n", clientFd);
+			clientFds.erase(clientFd);
+			close(clientFd);
+			continue;
+		} else {
+			// broadcast the message
+			sendToAllBut(clientFd, buffer, count);
+		}
+	}
+/****************************/
+}
+uint16_t readPort(char * txt){
+	char * ptr;
+	auto port = strtol(txt, &ptr, 10);
+	if(*ptr!=0 || port<1 || (port>((1<<16)-1))) error(1,0,"illegal argument %s", txt);
+	return port;
+}
+void setReuseAddr(int sock){
+	const int one = 1;
+	int res = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+	if(res) error(1,errno, "setsockopt failed");
+}
+void ctrl_c(int){
+	for(int clientFd : clientFds)
+		close(clientFd);
+	close(servFd);
+	printf("Closing server\n");
+	exit(0);
+}
+void sendToAllBut(int fd, char * buffer, int count){
+	int res;
+	decltype(clientFds) bad;
+	for(int clientFd : clientFds){
+		if(clientFd == fd) continue;
+		res = write(clientFd, buffer, count);
+		if(res!=count)
+			bad.insert(clientFd);
+	}
+	for(int clientFd : bad){
+		printf("removing %d\n", clientFd);
+		clientFds.erase(clientFd);
+		close(clientFd);
+	}
+}
+</code>
+====== Nawiązanie połączenia TCP ======
 <code cpp tcp_client.cpp>
 #include <sys/socket.h>

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