linux网络编程代码

UDP

收UDP

#include <sys/types.h>
#include <sys/socket.h>
#include<pthread.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
    if (argc != 2)
    {
        printf("Usage: %s port\n", argv[0]);
        exit(1);
    }
    printf("Welcome! This is a UDP server, I can only received message from client and reply with same message\n");
    
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(atoi(argv[1]));
    addr.sin_addr.s_addr = htonl(INADDR_ANY);

    int sock;
    if ( (sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    {
        perror("socket");
        exit(1);
    }
    if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
    {
        perror("bind");
        exit(1);
    }
    char buff[512];
    struct sockaddr_in clientAddr;
    int n;
    int len = sizeof(clientAddr);
    while (1)
    {
        n = recvfrom(sock, buff, 511, 0, (struct sockaddr*)&clientAddr, &len);
        if (n>0)
        {
            buff[n] = 0;
            printf("%s %u says: %s\n", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port), buff);
            n = sendto(sock, buff, n, 0, (struct sockaddr *)&clientAddr, sizeof(clientAddr));
            if (n < 0)
            {
                perror("sendto");
                break;
            }
        }
        else
        {
            perror("recv");
            break;
        }
    }
    return 0;
}

发UDP

#include <sys/types.h>
#include <sys/socket.h>
#include<pthread.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>


int main(int argc, char **argv)
{
    if (argc != 3)
    {
        printf("Usage: %s ip port", argv[0]);
        exit(1);
    }
    printf("This is a UDP client\n");
    struct sockaddr_in addr;
    int sock;

    if ( (sock=socket(AF_INET, SOCK_DGRAM, 0)) <0)
    {
        perror("socket");
        exit(1);
    }
    addr.sin_family = AF_INET;
    addr.sin_port = htons(atoi(argv[2]));
    addr.sin_addr.s_addr = inet_addr(argv[1]);
    if (addr.sin_addr.s_addr == INADDR_NONE)
    {
        printf("Incorrect ip address!");
        close(sock);
        exit(1);
    }

    char buff[512];
    int len = sizeof(addr);
    while (1)
    {
        gets(buff);
        int n;
        n = sendto(sock, buff, strlen(buff), 0, (struct sockaddr *)&addr, sizeof(addr));
        if (n < 0)
        {
            perror("sendto");
            close(sock);
            break;
        }
        n = recvfrom(sock, buff, 512, 0, (struct sockaddr *)&addr, &len);
        if (n>0)
        {
            buff[n] = 0;
            printf("received:");
            puts(buff);
        }
        else if (n==0)
        {
            printf("server closed\n");
            close(sock);
            break;
        }
        else if (n == -1)
        {
            perror("recvfrom");
            close(sock);
            break;
        }
    }
    
    return 0;
}

组播

   收组播流

   #include <stdio.h>

    #include <sys/types.h>
    #include <sys/socket.h>
    #include <string.h>
    #include <arpa/inet.h>
    #define MAXBUF 1500
    //#define PUERTO 8001
    //#define GRUPO "238.123.46.66"
     int main(int argc, char *argv[]){
            for(int i = 0;i<argc;i++){
                    printf("%s\n", argv[i]);
                }
                
        int port = atoi(argv[3]);
        int fd, n, r;
        struct sockaddr_in srv, cli;
        struct ip_mreq mreq;
        char buf[MAXBUF];
        memset( &srv, 0, sizeof(struct sockaddr_in) );
        memset( &cli, 0, sizeof(struct sockaddr_in) );
        memset( &mreq, 0, sizeof(struct ip_mreq) );
        srv.sin_family = AF_INET;
        srv.sin_port = htons(port);
        if( inet_aton(argv[2], &srv.sin_addr ) < 0 ) {
                perror("inet_aton");
                return -1;
        }
        if( (fd = socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP) ) < 0 ){
            perror("socket");
            return -1;
        }
        if( bind(fd, (struct sockaddr *)&srv, sizeof(srv)) < 0 ){
            perror("bind");
            return -1;
        }
        if (inet_aton(argv[2], &mreq.imr_multiaddr) < 0) {
            perror("inet_aton");
            return -1;
        }
        inet_aton( argv[1], &(mreq.imr_interface) );
        if( setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq,sizeof(mreq)) < 0 ){
            perror("setsockopt");
            return -1;
        }
        n = sizeof(cli);
        while(1){
                                
            if( (r = recvfrom(fd, buf, MAXBUF, 0, (struct sockaddr *)&cli, (socklen_t*)&n)) < 0 ){
                perror("recvfrom");
            }else{
                          printf("recv:%d\n",r);
                buf[r] = 0;
                FILE*fp  =fopen("/home/1.ts","ab");
                if(fp!=NULL){
                    fwrite(buf,1, r,fp);
                    fclose(fp);
                }
                //fprintf(stdout, "Mensaje desde %s: %s", inet_ntoa(cli.sin_addr), buf);
            }
        }
    }

用法：./testudp   192.168.200.105 238.123.46.66 8001

发组播流

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


#define PORT 10086
#define SIZE 128
int main(void)
{
    int ret = -1;
    int sockfd = -1;
    int i = 0;
    char buf[SIZE];
    struct sockaddr_in peer;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (-1 == sockfd)
    {
        perror("socket");
        goto err0;
    }

    memset(&peer, 0, sizeof(peer));
    peer.sin_family = AF_INET;
    peer.sin_port = htons(PORT);
    inet_pton(AF_INET, "224.0.0.88", &peer.sin_addr);

    printf("send data to UDP Server %s: %d\n", inet_ntoa(peer.sin_addr), ntohs(peer.sin_port));

    //向多播组发送消息
    while(1)
    {
        sprintf(buf, "hello world %d", i);
        ret = sendto(sockfd, buf, strlen(buf), 0, (void*)&peer, sizeof(peer));
        printf("ret: %d\n", ret);
        sleep(1);
        i++;
    }

    return 0;
err0:
    return -1;
}