我编写了一个代理，它接受来自host1的连接，并将连接转发给server2。
我接受一个连接然后我启动两个线程来处理连接...一个线程从主机1接收并发送到server2，另一个线程接收表单server2并发送到host1。
我的程序编译时没有错误，当我运行它并连接主机1时，我的程序在短时间后在函数WRITE失败，没有错误。
连接正常，在写入之前，它在短时间内失败。
您也可以找到我正在使用的书面功能。 当控制器写入套接字时，代码在CONTROLLER线程失败。
为什么程序失败而根本没有错误消息？
/*
* File Server0.c
* ECHO TCP SERVER with the following features:
* - Gets port from keyboard
* - SEQUENTIAL: serves one client at a time
*/
#define _POSIX_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include "mysocket.h"
#include <arpa/inet.h>
#include <fcntl.h> // for open
#include <unistd.h> // for close
#include <sys/types.h>
#include <signal.h>
#include <sys/wait.h>
#include <pthread.h> /* POSIX threads */
#define RBUFLEN 16384
/* FUNCTION PROTOTYPES */
int mygetline(char * line, size_t maxline, char *prompt);
int writen(SOCKET, char *, size_t);
void *mininet(void *);
void *controller(void *);
SOCKET s,s1[100],d[100];
int y=0,z=0;
int main()
{
uint16_t lport_n, lport_h;
int result;
socklen_t addrlen;
struct sockaddr_in saddr, caddr;
//fd_set readfds;
SOCKET conn_request_skt;
int bklog = 2,t=0;
pthread_t tid1[100];
pthread_t tid[100];
/* Initialize socket API if needed */
SockStartup();
/* input server port number */
lport_h=8888;
lport_n = htons(lport_h);
/* create the MININET socket */
printf("Creating first socketn");
s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s == INVALID_SOCKET)
err_fatal("socket() failed");
printf("done, socket number %un",s);
/* bind the MININET socket to any local IP address */
saddr.sin_family = AF_INET;
saddr.sin_port = lport_n;
saddr.sin_addr.s_addr = INADDR_ANY;
showAddr("Binding to address first socket", &saddr);
result = bind(s, (struct sockaddr *) &saddr, sizeof(saddr));
if (result == -1)
err_fatal("bind() failed");
printf("done.n");
/* listen on MININET socket */
printf ("Listening at socket %d with backlog = %d n",s,bklog);
result = listen(s, bklog);
if (result == -1)
err_fatal("listen() failed");
printf("done.n");
conn_request_skt=s;
/* accept next connection from mininet */
for(;;)
{
addrlen = sizeof(struct sockaddr_in);
z++;
y++;
t++;
d[t] = accept(conn_request_skt, (struct sockaddr *) &caddr, &addrlen);
if (d[t] == INVALID_SOCKET)
err_fatal("accept() failed");
showAddr("Accepted connection from", &caddr);
printf("new accepted connection socket: %un",d[t]);
/* serve the client on socket s */
pthread_create(&tid[t], NULL, mininet, &t);
pthread_create(&tid1[t], NULL, controller, &t);
sleep(1);
}
exit(0);
}
void *mininet (void *arg)
{
char buf[RBUFLEN]; /* reception buffer */
int n,t,k;
t=y;
k=z;
printf("MININET: m is: %d, c is: %d n ", t,k);
/* main server loop */
for (;;)
{
printf("MININET receiving on socket: %un",d[t]);
n=recv(d[t], buf, RBUFLEN-1, 0);
if (n < 0)
{
printf("MININET Read errorn");
closesocket(d[t]);
printf("MININET Socket %d closedn", d[t]);
return NULL;
}
else if (n==0)
{
printf("Connection closed by MININET on socket %dn",d[t]);
closesocket(d[t]);
break;
}
else
{
printf("Received line from MININET socket %03d :n", d[t]);
buf[n]=0;
printf("[%s]n",buf);
printf("MINET WRITING TO: %un",s1[k]);
if(writen(s1[k], buf, n) != n)
printf("Write error while replying TO CONTROLERn");
else
printf("Reply sent towards CONTROLERn");
}
}
return NULL;
}
void *controller (void *arg)
{
char buf[RBUFLEN]; /* reception buffer */
uint16_t lport_n1, lport_h1; /* port where the server listens (net/host byte ord resp.) */
int result, n,t,k;
struct sockaddr_in saddr1; /* server and client address structures */
t=y;
k=z;
printf("CONTROLLER: m is: %d, c is: %d n ", t,k);
/* Initialize socket API if needed */
SockStartup();
lport_h1=6633;
lport_n1 = htons(lport_h1);
printf("Creating CONTROLLER socketn");
s1[k] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s1[k] == INVALID_SOCKET)
err_fatal("socket() failed");
printf("done, socket number %un",s1[k]);
/* bind the socket to any local IP address */
saddr1.sin_family = AF_INET;
saddr1.sin_port = lport_n1;
saddr1.sin_addr.s_addr = INADDR_ANY;
/* connect */
showAddr("Connecting to target CONTROLER address", &saddr1);
result = connect(s1[k], (struct sockaddr *) &saddr1, sizeof(saddr1));
if (result == -1)
err_fatal("connect() failed");
printf("done.n");
/* main server loop */
for (;;)
{
printf("CONTROLER receiving on socket: %un",s1[k]);
n=recv(s1[k], buf, RBUFLEN-1, 0);
if (n < 0)
{
printf("CONTROLER Read errorn");
closesocket(s1[k]);
printf("Socket %d closedn", s1[k]);
return NULL;
}
else if (n==0)
{
printf("Connection closed by CONTROLER on socket %dn",s1[k]);
closesocket(s1[k]);
return NULL;
}
else
{
printf("Received line from CONTROLER socket %03d :n", s1[k]);
buf[n]=0;
printf("[%s]n",buf);
printf("CONTROLER writing on socket: %un",d[t]);
if(writen(d[t], buf, n) != n)
printf("Write error while replying TO MININETn");
else
printf("Reply sent towards MININETn");
}
}
return NULL;
}
/* Gets a line of text from standard input after having printed a prompt string Substitutes end of line with ''
Empties standard input buffer but stores at most maxline-1 characters in the passed buffer
*/
int mygetline(char *line, size_t maxline, char *prompt)
{
char ch;
size_t i;
printf("%s", prompt);
for (i=0; i< maxline-1 && (ch = getchar()) != 'n' && ch != EOF; i++)
*line++ = ch;
*line = '';
while (ch != 'n' && ch != EOF)
ch = getchar();
if (ch == EOF)
return(EOF);
else
return(1);
}
/* Writes nbytes from buffer ptr to stream socket s */
int writen(SOCKET s, char *ptr, size_t nbytes)
{
size_t nleft;
ssize_t nwritten;
for (nleft=nbytes; nleft > 0; )
{
nwritten = send(s, ptr, nleft, 0);
if (nwritten <=0)
return (nwritten);
else
{
nleft -= nwritten;
ptr += nwritten;
}
}
return (nbytes - nleft);
}