tcp-server and tcp-client added

clib/tcpnet.cpp

@@ -0,0 +1,118 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h> 
+
+#include "tcpnet.h"
+
+
+void error(const char *msg) {
+	// perror(msg);
+	throw std::runtime_error(msg);
+}
+
+// TODO do it as RAII
+TcpNet::TcpNet() {}
+
+
+#define TCPNET_BUFFER_SIZE 16256
+
+
+int TcpNet::server(int portno, std::function<std::pair<bool, std::string>(std::string)> process_request) {
+	int sockfd, newsockfd;
+	socklen_t clilen;
+
+	char buffer[TCPNET_BUFFER_SIZE];
+ 	struct sockaddr_in serv_addr, cli_addr;
+ 
+ 	int n;
+	sockfd = socket(AF_INET, SOCK_STREAM, 0);
+	if (sockfd < 0) 
+		error("ERROR opening socket");
+
+ 	bzero((char *) &serv_addr, sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_addr.s_addr = INADDR_ANY;
+	serv_addr.sin_port = htons(portno);
+
+	if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) 
+		error("ERROR on binding");
+
+	listen(sockfd,5);
+	clilen = sizeof(cli_addr);
+
+	int requests_processed = 0;
+	bool shutdown = false;
+	while (!shutdown) {
+		newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
+		if (newsockfd < 0) 
+			error("ERROR on accept");
+	
+		bzero(buffer,TCPNET_BUFFER_SIZE);
+	
+		n = read(newsockfd,buffer,TCPNET_BUFFER_SIZE - 1);
+		if (n < 0) error("ERROR reading from socket");
+
+		std::string request{buffer};
+		std::pair<bool, std::string> response = process_request(request);
+		shutdown = response.first;
+		std::string response_str = response.second;
+
+		n = write(newsockfd, response_str.c_str(), response_str.size());
+		if (n < 0)
+			error("ERROR writing to socket");
+	
+		close(newsockfd);
+		requests_processed++;
+	}
+
+	close(sockfd);
+
+	return requests_processed; 
+}
+
+std::string TcpNet::client(const std::string address, int portno, const std::string &content) {
+	int sockfd, n;
+	struct sockaddr_in serv_addr;
+	struct hostent *server;
+
+    	char buffer[TCPNET_BUFFER_SIZE];
+    
+	sockfd = socket(AF_INET, SOCK_STREAM, 0);
+	if (sockfd < 0) 
+		error("ERROR opening socket");
+
+ 	server = gethostbyname(address.c_str());
+	if (server == NULL) {
+		fprintf(stderr,"ERROR, no such host\n");
+		exit(0);
+	}
+
+	bzero((char *) &serv_addr, sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length);
+	serv_addr.sin_port = htons(portno);
+	
+	if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
+ 		error("ERROR connecting");
+    
+
+	n = write(sockfd, content.c_str(), strlen(content.c_str()));
+	if (n < 0) 
+		error("ERROR writing to socket");
+		
+	bzero(buffer, TCPNET_BUFFER_SIZE);
+	n = read(sockfd,buffer, TCPNET_BUFFER_SIZE - 1);
+	if (n < 0)
+		error("ERROR reading from socket");
+ 
+	close(sockfd);
+
+	return std::string(buffer);
+}
+