Linux Linux程序练习十一（网络编程大文件发送UDP版）

//网络编程发送端--大文件传输（UDP）
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>int main(int arg, char * args[])
{if (arg < 3){printf("please print two param ! \n");return -1;}int port = atoi(args[2]);int st = socket(AF_INET, SOCK_DGRAM, 0);if (st == -1){printf("create socket failed ! error message :%s\n", strerror(errno));return -1;}struct sockaddr_in addr;memset(&addr, 0, sizeof(addr));addr.sin_family = AF_INET;addr.sin_port = htons(port);addr.sin_addr.s_addr = inet_addr(args[1]);char buf[1024] = { 0 };int num = 0;//open the file streamFILE *pfr = NULL;int index=0;pfr = fopen("/home/test/2/1.dat", "r");if (pfr == NULL){printf("open the file failed ! error message :%s\n", strerror(errno));goto END;}while ((num = fread(buf, sizeof(char), sizeof(buf), pfr)) > 0){if (sendto(st, buf, sizeof(char)*num, 0, (struct sockaddr *) &addr,sizeof(addr)) == -1){printf("sendto failed ! error message :%s\n", strerror(errno));break;}printf("read %d num=%d\n",index++,num);}fclose(pfr);END: close(st);return 0;
}

//网络编程接收端--大文件传输（UDP）
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>int main(int arg, char *args[])
{if (arg < 2){printf("please print one param ! \n");return -1;}int port=atoi(args[1]);int st = socket(AF_INET, SOCK_DGRAM, 0);if (st == -1){printf("create socket failed ! error message:%s \n",strerror(errno));return -1;}struct sockaddr_in addr;memset(&addr,0,sizeof(addr));addr.sin_family=AF_INET;addr.sin_port=htons(port);addr.sin_addr.s_addr=htonl(INADDR_ANY);if(bind(st,(struct sockaddr *)&addr,sizeof(addr))==-1){printf("bind IP failed ! error message:%s \n",strerror(errno));goto END;}struct sockaddr_in client_addr;socklen_t client_addrlen=sizeof(client_addr);char buf[1024]={0};int num=0;int index=0;//define the file streamFILE * pfa=NULL;//open the file in append modepfa=fopen("/home/test/3/1.dat","a");if(pfa==NULL){printf("open the file failed ! error message :%s\n",strerror(errno));goto END;}while(1){memset(&client_addr,0,sizeof(client_addr));num=recvfrom(st,buf,sizeof(buf),0,(struct sockaddr *)&client_addr,&client_addrlen);if(num==-1){printf("recvform failed ! error message :%s\n",strerror(errno));break;}/*就算发送端关闭，recvfrom函数也不会返回0，而是会继续阻塞进程*//*else if(num==0){printf("the other side socket is closed !\n");break;}*/printf("recv %d num=%d\n",index++,num);fwrite(buf,sizeof(char),num,pfa);if(num<1024){printf("recv last! \n");break;}memset(buf,0,sizeof(buf));}fclose(pfa);END:close(st);return 0;
}

.SUFFIXES:.c .o
CC=gcc
SRCS1=udprecv.c
SRCS2=udpsend.c
OBJS1=$(SRCS1:.c=.o)
OBJS2=$(SRCS2:.c=.o)
EXEC1=mrecv
EXEC2=msendstart:$(OBJS1) $(OBJS2)$(CC) -o $(EXEC1) $(OBJS1)$(CC) -o $(EXEC2) $(OBJS2)@echo "-------ok-----------"
.c.o:$(CC) -Wall -g -o $@ -c $<
clean:rm -f $(OBJS1)rm -f $(EXEC1)rm -f $(OBJS2)rm -f $(EXEC2)

小结：UDP传输协议确实会出现丢包的情况，远没有TCP/IP协议来的安全，根据上图可以看出。