函数依赖简单例子

//server

#include <stdio.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <stdlib.h>

#include <errno.h>

#include <string.h>

#include <unistd.h>

#include <netinet/in.h>

#include <fcntl.h>

int Udp_Init(char *local_ip,unsigned short local_port,char *goal_ip,unsigned short goal_port,struct sockaddr_in *sendaddr,int flag)

{

int i,sockfd,Broadcast;

struct sockaddr_in local_addr;

sockfd=socket(AF_INET,SOCK_DGRAM,0);

if(sockfd==-1)

{

close(sockfd);

#ifndef DAMEON

printf( "socket creat error\n ");

#else

syslog(LOG_ERR, "UDP SOCKET Create error\n ");

#endif

return -1;

}

memset(&local_addr,0,sizeof(struct sockaddr));

local_addr.sin_family=AF_INET;

local_addr.sin_addr.s_addr=inet_addr(local_ip);

local_addr.sin_port=htons(local_port);

if(bind(sockfd,(struct sockaddr *)&(local_addr),sizeof(struct sockaddr))==-1)

{

close(sockfd);

printf( " %s\n ",local_ip);

#ifdef DAMEON

syslog(LOG_ERR, "UDP BIND\n ");

#else

printf( "bind error\n ");

#endif

return sockfd;

}

//判断套接字的创建是否为非阻塞方式

if(flag> 0){

if( (flag=fcntl(sockfd,F_SETFL,0)) < 0)

#ifndef DAMEON

printf( "fcntl error\n ");

#endif

flag |=O_NONBLOCK;

if( fcntl(sockfd,F_SETFL,flag) < 0)

#ifndef DAMEON

printf( "fcntl nonblock error\n ");

#endif

}

if( goal_ip != NULL ){

memset(sendaddr,0,sizeof(struct sockaddr));

sendaddr-> sin_family=AF_INET;

sendaddr-> sin_addr.s_addr=inet_addr(goal_ip);

sendaddr-> sin_port=htons(goal_port);

//判断发送IP是否为广播IP

if( (sendaddr->sin_addr.s_addr >> 24) == 0xff)

{

int Broadcast=1;

sendaddr-> sin_addr.s_addr = htonl(INADDR_BROADCAST);

if( setsockopt(sockfd,SOL_SOCKET,SO_BROADCAST,(const char *)&(Broadcast),sizeof(int)) == -1)

{

close(sockfd);

#ifdef DAMEON

syslog(LOG_ERR, "UDP BROADCAST SET error\n ");

#else

printf( " broadcast setup error\n ");

#endif

return -1;

}

}

printf("set sockfd broadcast ok\n");

}

printf("sockfd init ok\n");

return sockfd;

}

int main(int argc, char ** argv)

{

struct sockaddr_in sendaddr;

int sock_fd;

int count=100;

int rec;

if( argc <3 ){

printf("usage error input local IP to IP\n");

return ;

}

if( (sock_fd=Udp_Init(argv[1],9001,argv[2],9001,&sendaddr,0) ) == -1)

{

perror("udp_init error");

}

sleep(1);

printf("socket:%d\n",sock_fd);

while( count-- ){

rec=0;

rec=sendto(sock_fd, "hello",5, 0, (struct sockaddr*)&sendaddr, sizeof(struct sockaddr_in));

printf("sendto len:%d\n",rec);

rec=0;

usleep(100);

}

}

//client

#include <stdio.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <stdlib.h>

#include <errno.h>

#include <string.h>

#include <unistd.h>

#include <netinet/in.h>

#include <fcntl.h>

#include <assert.h>

//========================================================

static int sock_fd;

//========================================================

//name:int udpc_init(void *p)

//args:void *p

//retu:

//func:

//========================================================

int udpc_init(void *p){

int nSize,fBroadcast,count=1;

int port=*(int*)p;

struct sockaddr_in Local_rec_addr;

nSize = sizeof(struct sockaddr);

if( ( sock_fd = socket(AF_INET,SOCK_DGRAM,0) ) < 0 ){

perror("socket error");

return -1;

}

memset(&Local_rec_addr,0,sizeof(Local_rec_addr));

Local_rec_addr.sin_family=AF_INET;

Local_rec_addr.sin_port = htons(port);

int Broadcast=1;

if( setsockopt(sock_fd,SOL_SOCKET,SO_BROADCAST,(const char *)&(Broadcast),sizeof(int)) == -1){

perror("setsockopt error");

}

int flag=0;

if(flag > 0){

if((flag = fcntl(sock_fd,F_SETFL,0)) < 0 )

#ifndef DAMEON

perror( "fcntl error\n ");

#endif

flag |= O_NONBLOCK;

if(fcntl(sock_fd,F_SETFL,flag) < 0 )

#ifndef DAMEON

perror( "fcntl nonblock error\n ");

#endif

}

if( bind(sock_fd,(struct sockaddr *)&Local_rec_addr,sizeof(Local_rec_addr)) == -1){

perror("bind error");

return -1;

};

return sock_fd;

}

//========================================================

//name:int udpc_getdata(char *buff, int max)

//args:char *, int

//retu:the lenof recevd data.

//func:

//========================================================

int udpc_getdata(char *buff, int max){

printf("sock_fd:%d\n",sock_fd);

assert(buff != NULL);

char *buffp=buff;

int count=max;

int tmp;

struct sockaddr_in Remote_rec_addr;

int nSize = sizeof(struct sockaddr);

while(count >0)

{

tmp= recvfrom(sock_fd,buffp,count, 0,(struct sockaddr *)&(Remote_rec_addr), &nSize) ;

if(tmp < 0 ){

perror("recvfrom error");

break;

}

printf( " %s:%d\n ",buffp,tmp);

buffp +=tmp;

count -=tmp;

}

return max-count;

}

//========================================================

//name:int udpc_fina()

//args:

//retu:

//func:

//========================================================

int udpc_fina(){

close(sock_fd);

}

int main(int argc , char ** argv)

{

char buff[2000];

int recvlen;

int udp_port=9001;

memset((char *)buff, 0 , sizeof(buff));

if( udpc_init(&udp_port) == -1){

perror("init sock_fd error");

exit(1);

}

recvlen=udpc_getdata(buff, sizeof(buff));

udpc_fina();

return 0;

}