util_sock.c

samba-3.0.22.tar.gz 编译smb服务器的源码

		goto connect_again;
	}

	if (ret < 0 && (errno == EINPROGRESS || errno == EALREADY ||
			errno == EAGAIN)) {
		DEBUG(1,("timeout connecting to %s:%d\n",inet_ntoa(*addr),port));
		close(res);
		return -1;
	}

#ifdef EISCONN

	if (ret < 0 && errno == EISCONN) {
		errno = 0;
		ret = 0;
	}
#endif

	if (ret < 0) {
		DEBUG(2,("error connecting to %s:%d (%s)\n",
				inet_ntoa(*addr),port,strerror(errno)));
		close(res);
		return -1;
	}

	/* set it blocking again */
	set_blocking(res,True);

	return res;
}

/****************************************************************************
 Create an outgoing TCP socket to any of the addrs. This is for
 simultaneous connects to port 445 and 139 of a host or even a variety
 of DC's all of which are equivalent for our purposes.
**************************************************************************/

BOOL open_any_socket_out(struct sockaddr_in *addrs, int num_addrs,
			 int timeout, int *fd_index, int *fd)
{
	int i, resulting_index, res;
	int *sockets;
	BOOL good_connect;

	fd_set r_fds, wr_fds;
	struct timeval tv;
	int maxfd;

	int connect_loop = 10000; /* 10 milliseconds */

	timeout *= 1000; 	/* convert to microseconds */

	sockets = SMB_MALLOC_ARRAY(int, num_addrs);

	if (sockets == NULL)
		return False;

	resulting_index = -1;

	for (i=0; i<num_addrs; i++)
		sockets[i] = -1;

	for (i=0; i<num_addrs; i++) {
		sockets[i] = socket(PF_INET, SOCK_STREAM, 0);
		if (sockets[i] < 0)
			goto done;
		set_blocking(sockets[i], False);
	}

 connect_again:
	good_connect = False;

	for (i=0; i<num_addrs; i++) {

		if (sockets[i] == -1)
			continue;

		if (connect(sockets[i], (struct sockaddr *)&(addrs[i]),
			    sizeof(*addrs)) == 0) {
			/* Rather unlikely as we are non-blocking, but it
			 * might actually happen. */
			resulting_index = i;
			goto done;
		}

		if (errno == EINPROGRESS || errno == EALREADY ||
		    errno == EAGAIN) {
			/* These are the error messages that something is
			   progressing. */
			good_connect = True;
		} else if (errno != 0) {
			/* There was a direct error */
			close(sockets[i]);
			sockets[i] = -1;
		}
	}

	if (!good_connect) {
		/* All of the connect's resulted in real error conditions */
		goto done;
	}

	/* Lets see if any of the connect attempts succeeded */

	maxfd = 0;
	FD_ZERO(&wr_fds);
	FD_ZERO(&r_fds);

	for (i=0; i<num_addrs; i++) {
		if (sockets[i] == -1)
			continue;
		FD_SET(sockets[i], &wr_fds);
		FD_SET(sockets[i], &r_fds);
		if (sockets[i]>maxfd)
			maxfd = sockets[i];
	}

	tv.tv_sec = 0;
	tv.tv_usec = connect_loop;

	res = sys_select(maxfd+1, &r_fds, &wr_fds, NULL, &tv);

	if (res < 0)
		goto done;

	if (res == 0)
		goto next_round;

	for (i=0; i<num_addrs; i++) {

		if (sockets[i] == -1)
			continue;

		/* Stevens, Network Programming says that if there's a
		 * successful connect, the socket is only writable. Upon an
		 * error, it's both readable and writable. */

		if (FD_ISSET(sockets[i], &r_fds) &&
		    FD_ISSET(sockets[i], &wr_fds)) {
			/* readable and writable, so it's an error */
			close(sockets[i]);
			sockets[i] = -1;
			continue;
		}

		if (!FD_ISSET(sockets[i], &r_fds) &&
		    FD_ISSET(sockets[i], &wr_fds)) {
			/* Only writable, so it's connected */
			resulting_index = i;
			goto done;
		}
	}

 next_round:

	timeout -= connect_loop;
	if (timeout <= 0)
		goto done;
	connect_loop *= 1.5;
	if (connect_loop > timeout)
		connect_loop = timeout;
	goto connect_again;

 done:
	for (i=0; i<num_addrs; i++) {
		if (i == resulting_index)
			continue;
		if (sockets[i] >= 0)
			close(sockets[i]);
	}

	if (resulting_index >= 0) {
		*fd_index = resulting_index;
		*fd = sockets[*fd_index];
		set_blocking(*fd, True);
	}

	free(sockets);

	return (resulting_index >= 0);
}
/****************************************************************************
 Open a connected UDP socket to host on port
**************************************************************************/

int open_udp_socket(const char *host, int port)
{
	int type = SOCK_DGRAM;
	struct sockaddr_in sock_out;
	int res;
	struct in_addr *addr;

	addr = interpret_addr2(host);

	res = socket(PF_INET, type, 0);
	if (res == -1) {
		return -1;
	}

	memset((char *)&sock_out,'\0',sizeof(sock_out));
	putip((char *)&sock_out.sin_addr,(char *)addr);
	sock_out.sin_port = htons(port);
	sock_out.sin_family = PF_INET;

	if (connect(res,(struct sockaddr *)&sock_out,sizeof(sock_out))) {
		close(res);
		return -1;
	}

	return res;
}


/*******************************************************************
 Matchname - determine if host name matches IP address. Used to
 confirm a hostname lookup to prevent spoof attacks.
******************************************************************/

static BOOL matchname(char *remotehost,struct in_addr  addr)
{
	struct hostent *hp;
	int     i;
	
	if ((hp = sys_gethostbyname(remotehost)) == 0) {
		DEBUG(0,("sys_gethostbyname(%s): lookup failure.\n", remotehost));
		return False;
	} 

	/*
	 * Make sure that gethostbyname() returns the "correct" host name.
	 * Unfortunately, gethostbyname("localhost") sometimes yields
	 * "localhost.domain". Since the latter host name comes from the
	 * local DNS, we just have to trust it (all bets are off if the local
	 * DNS is perverted). We always check the address list, though.
	 */
	
	if (!strequal(remotehost, hp->h_name)
	    && !strequal(remotehost, "localhost")) {
		DEBUG(0,("host name/name mismatch: %s != %s\n",
			 remotehost, hp->h_name));
		return False;
	}
	
	/* Look up the host address in the address list we just got. */
	for (i = 0; hp->h_addr_list[i]; i++) {
		if (memcmp(hp->h_addr_list[i], (char *) & addr, sizeof(addr)) == 0)
			return True;
	}
	
	/*
	 * The host name does not map to the original host address. Perhaps
	 * someone has compromised a name server. More likely someone botched
	 * it, but that could be dangerous, too.
	 */
	
	DEBUG(0,("host name/address mismatch: %s != %s\n",
		 inet_ntoa(addr), hp->h_name));
	return False;
}

/*******************************************************************
 Return the DNS name of the remote end of a socket.
******************************************************************/

char *get_peer_name(int fd, BOOL force_lookup)
{
	static pstring name_buf;
	pstring tmp_name;
	static fstring addr_buf;
	struct hostent *hp;
	struct in_addr addr;
	char *p;

	/* reverse lookups can be *very* expensive, and in many
	   situations won't work because many networks don't link dhcp
	   with dns. To avoid the delay we avoid the lookup if
	   possible */
	if (!lp_hostname_lookups() && (force_lookup == False)) {
		return get_peer_addr(fd);
	}
	
	p = get_peer_addr(fd);

	/* it might be the same as the last one - save some DNS work */
	if (strcmp(p, addr_buf) == 0) 
		return name_buf;

	pstrcpy(name_buf,"UNKNOWN");
	if (fd == -1) 
		return name_buf;

	fstrcpy(addr_buf, p);

	addr = *interpret_addr2(p);
	
	/* Look up the remote host name. */
	if ((hp = gethostbyaddr((char *)&addr.s_addr, sizeof(addr.s_addr), AF_INET)) == 0) {
		DEBUG(1,("Gethostbyaddr failed for %s\n",p));
		pstrcpy(name_buf, p);
	} else {
		pstrcpy(name_buf,(char *)hp->h_name);
		if (!matchname(name_buf, addr)) {
			DEBUG(0,("Matchname failed on %s %s\n",name_buf,p));
			pstrcpy(name_buf,"UNKNOWN");
		}
	}

	/* can't pass the same source and dest strings in when you 
	   use --enable-developer or the clobber_region() call will 
	   get you */
	
	pstrcpy( tmp_name, name_buf );
	alpha_strcpy(name_buf, tmp_name, "_-.", sizeof(name_buf));
	if (strstr(name_buf,"..")) {
		pstrcpy(name_buf, "UNKNOWN");
	}

	return name_buf;
}

/*******************************************************************
 Return the IP addr of the remote end of a socket as a string.
 ******************************************************************/

char *get_peer_addr(int fd)
{
	struct sockaddr sa;
	struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
	socklen_t length = sizeof(sa);
	static fstring addr_buf;

	fstrcpy(addr_buf,"0.0.0.0");

	if (fd == -1) {
		return addr_buf;
	}
	
	if (getpeername(fd, &sa, &length) < 0) {
		DEBUG(0,("getpeername failed. Error was %s\n", strerror(errno) ));
		return addr_buf;
	}
	
	fstrcpy(addr_buf,(char *)inet_ntoa(sockin->sin_addr));
	
	return addr_buf;
}

/*******************************************************************
 Create protected unix domain socket.

 Some unixes cannot set permissions on a ux-dom-sock, so we
 have to make sure that the directory contains the protection
 permissions instead.
 ******************************************************************/

int create_pipe_sock(const char *socket_dir,
		     const char *socket_name,
		     mode_t dir_perms)
{
#ifdef HAVE_UNIXSOCKET
	struct sockaddr_un sunaddr;
	struct stat st;
	int sock;
	mode_t old_umask;
	pstring path;
        
	old_umask = umask(0);
        
	/* Create the socket directory or reuse the existing one */
        
	if (lstat(socket_dir, &st) == -1) {
		if (errno == ENOENT) {
			/* Create directory */
			if (mkdir(socket_dir, dir_perms) == -1) {
				DEBUG(0, ("error creating socket directory "
					"%s: %s\n", socket_dir, 
					strerror(errno)));
				goto out_umask;
			}
		} else {
			DEBUG(0, ("lstat failed on socket directory %s: %s\n",
				socket_dir, strerror(errno)));
			goto out_umask;
		}
	} else {
		/* Check ownership and permission on existing directory */
		if (!S_ISDIR(st.st_mode)) {
			DEBUG(0, ("socket directory %s isn't a directory\n",
				socket_dir));
			goto out_umask;
		}
		if ((st.st_uid != sec_initial_uid()) || 
				((st.st_mode & 0777) != dir_perms)) {
			DEBUG(0, ("invalid permissions on socket directory "
				"%s\n", socket_dir));
			goto out_umask;
		}
	}
        
	/* Create the socket file */
        
	sock = socket(AF_UNIX, SOCK_STREAM, 0);
        
	if (sock == -1) {
		perror("socket");
                goto out_umask;
	}
        
	pstr_sprintf(path, "%s/%s", socket_dir, socket_name);
        
	unlink(path);
	memset(&sunaddr, 0, sizeof(sunaddr));
	sunaddr.sun_family = AF_UNIX;
	safe_strcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)-1);
        
	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
		DEBUG(0, ("bind failed on pipe socket %s: %s\n", path,
			strerror(errno)));
		goto out_close;
	}
        
	if (listen(sock, 5) == -1) {
		DEBUG(0, ("listen failed on pipe socket %s: %s\n", path,
			strerror(errno)));
		goto out_close;
	}
        
	umask(old_umask);
	return sock;

out_close:
	close(sock);

out_umask:
	umask(old_umask);
	return -1;

#else
        DEBUG(0, ("create_pipe_sock: No Unix sockets on this system\n"));
        return -1;
#endif /* HAVE_UNIXSOCKET */
}