Linux网络编程之使用UDP传输文件

原创作品，转载时请务必以超链接形式标明文章原始出处:http://blog.csdn.net/gqb666/article/details/8970207,作者:gqb666

         接上篇博文Linux网络编程之使用TCP传输文件。最近在写Linux网络方面的demo,用UDP实现了一个简单的传输文件程序，适用于网卡设备及TCP/IP协议栈及网络环境测试时使用。当然这里要说的是，一般通过网络传输文件不会选择UDP协议，因为UPD提供不可靠的传输，文件传输过程中会出现丢包现象而导致文件传输错误。这里要实现UDP传输文件的目的是为了测试网卡的丢包率，然后与正常网络的丢包率进行比较，从而可以检验网卡及网络环境的质量。本文仅将其雏形写出。其功能是使用UDP协议从client端向server端传输文件，用法如下:

     编译：

           client:gcc -o client client.c

           server:gcc -o server server.c

     运行：

           client端：./client <server IP> <端口号> <上传文件名>

           server端：./server <端口号> <保存为文件名>

其中，server端先运行，client端与server端的端口号必须一致并且不能与已知端口冲突（例如8888即可）

下面将代码贴上：

server端代码:server.c

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#define    FINISH_FLAG    "FILE_TRANSPORT_FINISH"#define    MAXLINE        1024 void usage(char *command){    printf("usage :%s portnum filename\n", command);    exit(0);}int main(int argc,char **argv){    struct sockaddr_in     serv_addr;    struct sockaddr_in     clie_addr;    char                   buf[MAXLINE];    int                    sock_id;    int                    recv_len;    int                    clie_addr_len;    FILE                   *fp;    if (argc != 3) {        usage(argv[0]);    }/* Create the the file commented by guoqingbo*/    if ((fp = fopen(argv[2], "w")) == NULL) {        perror("Creat file failed");        exit(0);    }    if ((sock_id = socket(AF_INET,SOCK_DGRAM,0)) < 0) {        perror("Create socket failed\n");        exit(0);    }/*fill the server sockaddr_in struct commented by guoqingbo*/      memset(&serv_addr,0,sizeof(serv_addr));    serv_addr.sin_family = AF_INET;    serv_addr.sin_port = htons(atoi(argv[1]));    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);    if (bind(sock_id,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0 ) {        perror("Bind socket faild\n");        exit(0);    }    /* server part commented by guoqingbo*/      clie_addr_len = sizeof(clie_addr);    bzero(buf, MAXLINE);     while (recv_len = recvfrom(sock_id, buf, MAXLINE, 0,(struct sockaddr *)&clie_addr, &clie_addr_len)) {        if(recv_len < 0) {            printf("Recieve data from client failed!\n");            break;        }        printf("#");        if ( strstr(buf, FINISH_FLAG) != NULL ) {            printf("\nFinish receiver finish_flag\n");            break;        }        int write_length = fwrite(buf, sizeof(char), recv_len, fp);        if (write_length < recv_len) {            printf("File write failed\n");            break;        }        bzero(buf, MAXLINE);    }    printf("Finish recieve\n");    fclose(fp);     close(sock_id);     return 0;}

client端代码:client.c

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <fcntl.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#define    FINISH_FLAG    "FILE_TRANSPORT_FINISH"#define    MAXLINE        1024void usage(char *command){    printf("usage :%s ipaddr portnum filename\n", command);    exit(0);}int main(int argc,char **argv){    FILE                   *fp;    struct sockaddr_in     serv_addr;    char                   buf[MAXLINE];    int                    sock_id;    int                    read_len;    int                    send_len;    int                    serv_addr_len;    int                    i_ret;    int                    i;    if (argc != 4) {        usage(argv[0]);    }    /* open the file to be transported commanted by guoqingbo*/    if ((fp = fopen(argv[3],"r")) == NULL) {        perror("Open file failed\n");        exit(0);    }    /* create the socket commanted by guoqingbo*/    if ((sock_id = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {        perror("Create socket failed");        exit(0);    }    memset(&serv_addr,0,sizeof(serv_addr));    serv_addr.sin_family = AF_INET;    serv_addr.sin_port = htons(atoi(argv[2]));    inet_pton(AF_INET, argv[1], &serv_addr.sin_addr);    serv_addr_len = sizeof(serv_addr);    /* connect the server commanted by guoqingbo*/    i_ret = connect(sock_id, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr));    if (-1 == i_ret) {        perror("Connect socket failed!\n");        exit(0);    }    /* transport the file commented by guoqingbo*/    bzero(buf, MAXLINE);    while ( (read_len = fread(buf, sizeof(char), MAXLINE, fp)) > 0 ) {        send_len = send(sock_id, buf, read_len, 0);        if ( send_len < 0 ) {            perror("Send data failed\n");            exit(0);        }        bzero(buf, MAXLINE);    }    fclose(fp);    /* send the end_flag commented by guoqingbo*/    bzero(buf, MAXLINE);    strcpy(buf, FINISH_FLAG);    buf[strlen(buf)] = '\0';    for (i = 1000; i>0; i--) {        send_len = send(sock_id, buf, strlen(buf)+1, 0);        if ( send_len < 0 ) {            printf("Finish send the end string\n");            break;        }    }    close(sock_id);    printf("Send finish\n");    return 0;}

上接博文： Linux网络编程之使用TCP传输文件