netutil.c

一个收集所有最基本功能的函数库；所有的函数都是尽量短小和简单 使用 doxygen 生成文档 所有代码以在 Linux 系统上可以编译并运行为准；每当在 lib 目录里增加了一个功能函数

/***************************************************************************
 *            netutil.c
 *
 *  Mon May 21 18:07:20 2007
 *  Copyright  2007  kf701
 *  Email <kf701.ye AT gmail.com>
 ****************************************************************************/

/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 


#include <errno.h>
#include <sys/time.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include "kf701.h"

/**
 * @brief open a TCP socket and connect to ip:port
 * @param ip server ip
 * @param port server port
 * @param timeout seconds for time out
 * @retval socket fd success
 * @retval -1 error
 */
int connect_nonblock(char *ip,uint16_t port,uint32_t timeout)
{
	int sockfd, flags, n;
	int sock_error;
	socklen_t len;
	fd_set	rset, wset;
	struct timeval	tval;
	struct sockaddr_in servaddr;	
	struct hostent *hent;
		
	if (NULL == ip)
		return -1;
	
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0) 
		return -1;	
	hent = gethostbyname(ip);
	if (NULL == hent) 
	{
		close(sockfd);
		return -1;
	}
	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(port);
	servaddr.sin_addr = *(struct in_addr *)hent->h_addr;

	flags = fcntl(sockfd, F_GETFL, 0);
	if (-1 == flags) 
	{
		close(sockfd);
		return -1;
	}
	if ( -1 == fcntl(sockfd, F_SETFL, flags | O_NONBLOCK) )
	{
		close(sockfd);
		return -1;
	}

	if ( (n = connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0) )
		if (errno != EINPROGRESS)
		{
			close(sockfd);
			return -1;
		}

	/* Do whatever we want while the connect is taking place. */
	if ( 0 == n)
		return sockfd;	/* connect completed immediately */

	FD_ZERO(&rset);
	FD_SET(sockfd, &rset);
	wset = rset;
	tval.tv_sec = timeout;
	tval.tv_usec = 0;

	if ( select(sockfd+1, &rset, &wset, NULL, timeout ? &tval : NULL) == 0 ) 
	{
		close(sockfd);		/* timeout */		
		return -1;
	}

	if (FD_ISSET(sockfd, &rset) || FD_ISSET(sockfd, &wset)) 
	{		
		len = sizeof(sock_error);
		if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &sock_error, &len) < 0)
		{  
			close(sockfd);			
			return -1;
		}
		if (sock_error)
		{
			errno = sock_error;
			close(sockfd);
			return -1;
		}		
	} else {
		//printf("select error: sockfd not set");
		close(sockfd);
		return -1;
	}
	/* restore file status flags */
	if ( fcntl(sockfd, F_SETFL, flags) < 0 )
	{
		close(sockfd);
		return -1;
	}
	return sockfd;
	
}

/**
 * @brief open a TCP socket listen on port
 * @param port listen port
 * @retval socket fd success
 * @retval -1 error
 */
int open_listenfd(uint16_t port)
{
        int listenfd, optval = 1;
        struct sockaddr_in serveraddr;

        if( ( listenfd = socket( AF_INET, SOCK_STREAM, 0 )) < 0 )
        {
                return -1;
        }

        if( setsockopt( listenfd, SOL_SOCKET, SO_REUSEADDR, (const void*)&optval, sizeof(int) ) < 0 )
                goto error;

        bzero(( char* )&serveraddr, sizeof(serveraddr) );
        serveraddr.sin_family = AF_INET;
        serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
        serveraddr.sin_port = htons((uint16_t)port);

        if( bind( listenfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr) ) < 0 )
        {
                goto error ;
        }

        if( listen( listenfd, 5 ) < 0 )
                goto error;

        return listenfd;
error:
        close(listenfd);
        return -1;
}

/**
 * @brief open a UDP socket listen on port
 * @param port listen port
 * @retval socket fd success
 * @retval -1 error
 */
int open_udp( uint16_t port)
{
	int fd;
	fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if ( fd == -1 )
	{
		sys_message("%s,%d:socket error\n",__func__,__LINE__);
		return -1;
	}
	 
	struct sockaddr_in addr;
	memset((char*) &(addr),0, sizeof((addr)));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	addr.sin_port = htons(port);

	if ( bind( fd,(struct sockaddr*)&addr, sizeof(addr)) != 0 )
	{
	   switch (errno)
	   {
		  case 0:
		  {
			 sys_message("%s,%d:bind error\n",__func__,__LINE__);
			 return -1;
		  }
		  case EADDRINUSE:
		  {
			 sys_message("%s,%d:port in use\n",__func__,__LINE__);
			 return -1;
		  }
		  break;
		  case EADDRNOTAVAIL:
		  {
			 sys_message("%s,%d:Cannot assign requested address\n",__func__,__LINE__);
			 return -1;
		  }
		  break;
		  default:
		  {
			 sys_message("%s,%d:error=%s\n",__func__,__LINE__,strerror(errno));
			 return -1;
		  }
		  break;
	   }
	}
	return fd;
}