Net004

Net003

単純な server program †

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <errno.h>
extern int errno;

int main(int argc, char* argv[])
{
	struct sockaddr_in saddr;
	struct sockaddr_in caddr;
	socklen_t calen;

	int sd;
	int cd;
	int port;

	/* Check the command-line arguments */
	if(argc != 2)
	{
		fprintf(stderr, "Usage: %s port\n", argv[0]);
		return (-1);
	}
	
	port = atoi(argv[1]);
	if(port <= 0)
	{
		fprintf(stderr, "Illegal port number (%d)\n", port);
		return (-1);
	}

	/* Set the server address */
	memset(&saddr, 0, sizeof(saddr));
	memset(&caddr, 0, sizeof(caddr));

	saddr.sin_family = AF_INET;
	saddr.sin_port = htons((u_short)port);
	saddr.sin_addr.s_addr = INADDR_ANY;

	/* Create socket for listen port and bind the server address */
	if((sd = socket( PF_INET, SOCK_STREAM, 0)) == -1)
		return errno;
	if(bind(sd, (const struct sockaddr*)&saddr, sizeof(saddr)) == -1)
	{
		close(sd);
		return errno;
	}

	/* Listen the service port */
	if(listen(sd, 5) == -1)
	{
		close(sd);
		return errno;
	}

	while(1)
	{
		/* Clear the address for accept */
		memset(&caddr, 0, sizeof(caddr));
		calen = sizeof(caddr);
		/* Dequeue the requested connection in the listen socket */
		if((cd = accept(sd,(struct sockaddr*)&caddr, &calen)) == -1)
		{
			close(sd);
			return errno;
		}
		send(cd, "Hello\r\n", 7, 0);
		close(cd);
	}

	/* Server done. (Never come) */
	close(sd);
	return 0;
}