我在这个项目上遇到了困难。一切都在工作，除了二进制文件，可能是因为它们相当大，并期望超时。 packetErrorSends类似于send，但它们随机丢弃数据包。我只把它们放在客户端以隔离我的问题。我想要的算法是发送一段文件，如果它接收到，则发送一个＆＃39; s＆＃39;并继续阅读并发送发件。如果超时，请发送＆＃39; e＆＃39;然后跳入循环，重新发送当前片段并重新开始下一个状态更新。 ＆＃34;虽然＆＃34;检查状态，决定是继续还是重新发送该片段。问题是，什么时候超时，服务器卡在该循环中重新发送最后一块数据，客户端保持超时并发回（打印报表的目的）任何线索是什么＆＃39发生了什么？
客户端：
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "packetErrorSend.h"
#include <sys/time.h>
ssize_t recvx(int sockfd, void *buf, size_t len) {
int var = recv(sockfd, buf, len, 0);
if(var != -1)
{
return var;
} else {
printf("%s \n","Did not receive.");
exit(1);
}
}
int main(int argc, char *argv[])
{
char buf[MAX_PACKET_DATA_SIZE];
struct addrinfo hints;
struct addrinfo *rp, *result;
int bytes_received = 1;
int s;
char *server;
char *port;
char *file;
int fd = -1; //file descriptor
int bytes_written = 1;
fd_set readfds;
struct timeval tv;
int rv = 0;
int status;
char sendStatus[1];
if (argc==4)
{
server = argv[1];
port = argv[2];
file = argv[3];
}
else
{
fprintf(stderr, "invalid # of arguments\n");
exit(1);
}
/* Translate host name into peer's IP address */
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = 0;
hints.ai_protocol = 0;
if ((s = getaddrinfo(server, port, &hints, &result)) != 0 )
{
fprintf(stderr, "%s: getaddrinfo: %s\n", argv[0], gai_strerror(s));
exit(1);
}
/* Iterate through the address list and try to connect */
for (rp = result; rp != NULL; rp = rp->ai_next)
{
if ((s = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol)) == -1 )
{
continue;
}
if (connect(s, rp->ai_addr, rp->ai_addrlen) != -1)
{
break;
}
close(s);
}
if (rp == NULL)
{
perror("stream-talk-client: connect");
exit(1);
}
freeaddrinfo(result);
FD_ZERO(&readfds);
FD_SET(s, &readfds);
packetErrorSend(s, file, strlen(file)+1, 0);
tv.tv_sec = 2;
rv = select(s+1, &readfds, NULL, NULL, &tv);
if (rv == -1) {
perror("select"); // error occurred in select()
} else if (rv == 0) {
printf("Timeout occurred on filename! No data after 2 seconds.\n");
close(s);
exit(0);
} else {
status = recvx(s,buf,1);
}
if(status == 0 || buf[0] == 'e')
{
fprintf(stderr, "Server Error: unable to access file %s \n", file);
close(s);
exit(0);
}
if(buf[0] == 's')
{
fd =open(file, O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
if(fd == -1)
{
fprintf(stderr,"%s \n","Client Error: Open failed");
close(s);
exit(0);
}
FD_ZERO(&readfds);
FD_SET(s, &readfds);
bytes_received = MAX_PACKET_DATA_SIZE;
// while(bytes_received >= MAX_PACKET_DATA_SIZE)
while(bytes_received > 0)
{
tv.tv_sec = 3;
rv = select(s+1, &readfds, NULL, NULL, &tv);
if (rv == -1) {
perror("select");
} else if (rv == 0) {
printf("bytes_received in timeout %d \n", bytes_received );
printf("Timeout occurred! No data after 3 seconds.\n");
sendStatus[0] = 'e';
send(s,sendStatus,1,0);
} else {
bytes_received = recvx(s, buf, MAX_PACKET_DATA_SIZE);
printf("%d\n", bytes_received);
sendStatus[0]='s';
packetErrorSend(s,sendStatus,1,0);
}
bytes_written = write(fd,buf,bytes_received);
if(bytes_written == -1)
{
fprintf(stderr,"%s \n", "Client Error: Write error");
break;
}
}
if(bytes_received == -1)
{
fprintf(stderr,"%s \n", "Client Error: Error receiving file");
exit(0);
}
if(close(fd) != 0)
{
printf("%s \n", "Client Error: File did not close successfully");
exit(0);
}
close(s);
}
return 0;
}
服务器：
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include "packetErrorSend.h"
#include <sys/time.h>
#define SERVER_PORT "5432"
#define MAX_PENDING 5
int main(int argc, char *argv[])
{
struct addrinfo hints;
struct addrinfo *rp, *result;
char file[MAX_PACKET_DATA_SIZE];
int s, new_s;
int bytes_transferred = 0;
int fd; //file descriptor
char status[1];
/* Build address data structure */
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
hints.ai_protocol = 0;
hints.ai_canonname = NULL;
hints.ai_addr = NULL;
hints.ai_next = NULL;
/* Get local address info */
if ((s = getaddrinfo(NULL, argv[1], &hints, &result)) != 0 )
{
fprintf(stderr, "%s: getaddrinfo: %s\n", argv[0], gai_strerror(s));
exit(1);
}
/* Iterate through the address list and try to perform passive open */
for (rp = result; rp != NULL; rp = rp->ai_next)
{
if ((s = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol)) == -1 )
{
continue;
}
if (!bind(s, rp->ai_addr, rp->ai_addrlen))
{
break;
}
close(s);
}
if (rp == NULL)
{
perror("stream-talk-server: bind");
exit(1);
}
if (listen(s, MAX_PENDING) == -1)
{
perror("stream-talk-server: listen");
close(s);
exit(1);
}
freeaddrinfo(result);
/* Wait for connection, then receive and print text */
while(1)
{
for(int i = 0; i < sizeof(file); i++)
{
file[i] = '\0';
}
if ((new_s = accept(s, rp->ai_addr, &(rp->ai_addrlen))) < 0)
{
perror("stream-talk-server: accept");
close(s);
exit(0);
}
if ((bytes_transferred = recv(new_s,file,sizeof(file),0)) > 0)
{
fd = open(file,O_RDONLY);
if(fd < 0)
{
perror("open");
status[0] = 'e';
send(new_s,status,1,0);
close(new_s);
exit(0);
}
status[0] = 's';
send(new_s,status,1,0);
int datasent = 0;
bytes_transferred = 1;
while(bytes_transferred > 0)
{
status[0] = s;
bytes_transferred = read(fd,file,MAX_PACKET_DATA_SIZE);
printf("%d\n",bytes_transferred);
datasent = send(new_s,file,bytes_transferred,0);
if (datasent < 0)
{
perror("send");
break;
}
recv(new_s,status,1,0);
printf("before while: %c \n", status[0]);
while(status[0] == 'e')
{
recv(new_s,status,1,0);
send(new_s,file,bytes_transferred,0);
printf("in while: %c \n", status[0]);
}
}
if (bytes_transferred == 0)
{
break;
}
else if(bytes_transferred == -1)
{
perror("read");
close(new_s);
exit(0);
}
}
}
close(fd);
close(new_s);
return 0;
}