套接字編程

UDP 編寫

server.c

#include<stdio.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<arpa/inet.h>
#include<netinet/in.h>


void Usage(char* prc)
{
    printf("Usage: %s [local ip][local port]",prc);
}



int main(int argc,char* argv[])
{
    if(argc!=3)
    {
        Usage(argv[0]);
        return 1;
    }

    //sock
    int sock=socket(AF_INET,SOCK_DGRAM,0);

    if(sock<0)
    {
        perror("sock");
        return 2;
    }

    struct sockaddr_in local;
    local.sin_family=AF_INET;
    local.sin_port=htons(atoi(argv[2]));
    local.sin_addr.s_addr=inet_addr(argv[1]);

    //
    if(bind(sock,(struct sockaddr*)&local,sizeof(local))<0)
    {
        perror("bind");
        return 3;
    }

    char buf[1024];
    struct sockaddr_in client_socket;
    while(1)
    {
        socklen_t len=sizeof(client_socket);
        size_t s=recvfrom(sock,buf,sizeof(buf)-1,0,(struct sockaddr*)&client_socket,&len);

        if(s>0)
        {
            buf[s]=0;
            printf("[%s][%d]:%s\n",inet_ntoa(client_socket.sin_addr),ntohs(client_socket.sin_port),buf);

            //write
            ssize_t _s=sendto(sock,buf,strlen(buf),0,(struct sockaddr *)&client_socket,sizeof(client_socket));

            if(_s<0)
            {
                perror("sendto");
            }
        }
    }
    return 0;
}

cllient.c

#include<stdio.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<arpa/inet.h>
#include<netinet/in.h>


void Usage(char* prc)
{
    printf("Usage: %s [server ip][local port]",prc);
}



int main(int argc,char* argv[])
{
    if(argc!=3)
    {
        Usage(argv[0]);
        return 1;
    }

    //sock
    int sock=socket(AF_INET,SOCK_DGRAM,0);

    if(sock<0)
    {
        perror("sock");
        return 2;
    }

    struct sockaddr_in server;
    server.sin_family=AF_INET;
    server.sin_port=htons(atoi(argv[2]));
    server.sin_addr.s_addr=inet_addr(argv[1]);


      //無連接
    char buf[1024];
    while(1)
    {
        printf("Please Enter:");
        fflush(stdout);

        ssize_t s=read(0,buf,sizeof(buf));
        if(s>0)
        {

            buf[s-1]=0;
            ssize_t _s=sendto(sock,buf,strlen(buf),0,(struct sockaddr *)&server,sizeof(server));

            if(_s<0)
            {
                perror("sendto");
            }
            ssize_t s=recvfrom(sock,buf,sizeof(buf)-1,0,0,0);

            if(s>0)
            {
                buf[s]=0;
                printf("server echo:%s\n",buf);
            }
        }
    }
    return 0;
}

TCP 編寫

int main(int argc,char* argv[])
{

    if(argc!=3)
    {
        printf("Usage:%s [service ip][service port]\n",argv[0]);
        return 1;
    }

    int sock=socket(AF_INET,SOCK_STREAM,0);

    //create ipv4 socket 
    struct sockaddr_in server_socket;
    struct sockaddr_in client_socket;
    bzero(&server_socket,sizeof(server_socket));
    //fill addr port

    server_socket.sin_family=AF_INET;
    server_socket.sin_addr.s_addr=inet_addr(argv[1]);
    server_socket.sin_port=htons(atoi(argv[2]));

    if(bind(sock,(struct sockaddr*)&server_socket,sizeof(struct sockaddr_in))<0)
    {
        perror("bind");
        close(sock);
        return 1; 
    }

    int new_sock=accept(sock,(struct sockaddr*)&client_socket,&len);   //return fd


        if(new_sock<0)
        {
            //perror("accept ");
            continue;
        }
    while(1)
        {
            ssize_t s=read(new_sock,buf,sizeof(buf));
            if(s>0)
            {
                buf[s]=0;
                printf("Client #:%s\n",buf);
                write(new_sock,buf,strlen(buf));
            }else if(s==0)
            {
                printf("client quit!\n");
                break;
            }
            else 
            {
                perror("read");
            }
        }
        close(new_sock);
    }
    return 0;
}