#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <head.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>#define PORT 69       //端口號：填服務器綁定端口號
#define IP   "192.168.1.101"   //IP地址：windows的IP地址int upload(int cfd,struct sockaddr_in sin)
{char filename[20] = "";printf("請輸入要上傳的文件名>>> ");scanf("%s", filename);while(getchar()!=10);//判斷文件存不存在int fd = open(filename,O_RDONLY);if(fd < 0){ERR_MSG("open");return -1;}//發送數據char buf[516] = "";int size = sprintf(buf, "%c%c%s%c%s%c", 0, 2, filename, 0, "octet", 0);if(sendto(cfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,sizeof(sin)) < 0) {ERR_MSG("sendto");return -1;}printf("sendto success\n");socklen_t addrlen = sizeof(sin);ssize_t res = 0;unsigned short num = 0;      //本地記錄的塊編號while(1){bzero(buf, sizeof(buf));//接收服務器的應答res = recvfrom(cfd, buf, sizeof(buf), 0, (struct sockaddr*)&sin, &addrlen);if(res < 0){ERR_MSG("recvfrom");break;}if(4 == buf[1]){if(htons(num) == *(unsigned short*)(buf+2)){//組數據包給服務器num++;*(unsigned short*)buf = htons(3);*(unsigned short*)(buf+2) = htons(num);res = read(fd, buf+4, 512);if(res < 0){break;}else if(0 == res){printf("文件：%s 上傳完畢\n", filename);break;}//發送數據包if(sendto(cfd, buf, res+4, 0, (struct sockaddr*)&sin, sizeof(sin)) < 0){ERR_MSG("sendto");return -1;}}}else if(5 == buf[1])//錯誤包{printf("MSG_ERR: code[%d] msg[%s] __%d__\n", \ntohs(*(unsigned short*)(buf+2)), buf+4, __LINE__);break;}}close(fd);return 0;
}int download(int cfd,struct sockaddr_in sin)
{char buf[516] = "";char filename[20] = "";printf("請輸入要下載的文件名>>> ");scanf("%s", filename);while(getchar()!=10);//發送下載請求//組協議包int size = sprintf(buf, "%c%c%s%c%s%c", 0, 1, filename, 0, "octet", 0);//sendto if(sendto(cfd, buf, size, 0, (struct sockaddr*)&sin, sizeof(sin)) < 0){ERR_MSG("sendto");return -1;}//本地創建并打開要下載的文件int fd = -1;     //必須初始化一個無意義的文件描述符，否則下面的closesocklen_t addrlen = sizeof(sin);ssize_t res = 0;unsigned short num = 0;      //本地記錄的塊編號//循環接收數據包，回復ACkwhile(1){bzero(buf, sizeof(buf));//接收數據包res = recvfrom(cfd, buf, sizeof(buf), 0, (struct sockaddr*)&sin, &addrlen);if(res < 0){ERR_MSG("recvfrom");break;}if(3 == buf[1])     //數據包{if(htons(num+1) == *(unsigned short*)(buf+2)){num++;if(-1 == fd){fd = open(filename, O_WRONLY|O_CREAT|O_TRUNC, 0664);if(fd < 0){ERR_MSG("open");break;}}//將獲取到的數據，寫入到文件中if(write(fd, buf+4, res-4) < 0){ERR_MSG("write");break;}buf[1] = 4;if(sendto(cfd, buf, 4, 0, (struct sockaddr*)&sin, sizeof(sin)) < 0){ERR_MSG("sendto");break;}if(res-4 < 512){printf("======= 文件下載完畢 =======\n");break;}}}else if(5 == buf[1])//錯誤包{printf("MSG_ERR: code[%d] msg[%s] __%d__\n", \ntohs(*(unsigned short*)(buf+2)), buf+4, __LINE__);break;}}close(fd);return 0;
}
int main(int argc, const char *argv[])
{//創建報式套接字int cfd = socket(AF_INET,SOCK_DGRAM,0);if(cfd < 0){ERR_MSG("socket");return -1;}printf("cfd = %d\n",cfd);//綁定客戶端的地址信息結構體到套接字上--->非必須綁定//若不綁定，則操作系統會給客戶端綁定上客戶端所在的主機IP以及隨機端口(49151~65535)//填充地址信息結構體，真實的地址信息結構體根據地址族制定//AF_INET：man 7 ip//要連接哪個服務器，就填對應服務器的IP和端口struct sockaddr_in sin;sin.sin_family      = AF_INET;       //必須填AF_INETsin.sin_port        = htons(PORT);   //端口號：填服務器綁定端口號sin.sin_addr.s_addr = inet_addr(IP);  //IP地址：服務器綁定的IP地址char c = 0;while(1){	printf("-------------------------\n");printf("---------1.下載----------\n");printf("---------2.上傳----------\n");printf("-------------------------\n");printf("請輸入>>> ");c = getchar();while(getchar()!=10);switch(c){case '1' :download(cfd,sin);break;case '2' :upload(cfd,sin);break;default :printf("輸入錯誤，請重新輸入\n");break;}while(getchar()!=10);}//關閉所有文件描述符close(cfd);return 0;
}