ntpdc.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

	else
	    tvo = tvsout;
	
	FD_SET(sockfd, &fds);
	n = select(sockfd+1, &fds, (fd_set *)0, (fd_set *)0, &tvo);

	if (n == -1) {
		warning("select fails", "", "");
		return -1;
	}
	if (n == 0) {
		/*
		 * Timed out.  Return what we have
		 */
		if (firstpkt) {
			(void) fprintf(stderr,
				       "%s: timed out, nothing received\n", currenthost);
			return ERR_TIMEOUT;
		} else {
			(void) fprintf(stderr,
				       "%s: timed out with incomplete data\n",
				       currenthost);
			if (debug) {
				printf("Received sequence numbers");
				for (n = 0; n <= MAXSEQ; n++)
				    if (haveseq[n])
					printf(" %d,", n);
				if (lastseq != 999)
				    printf(" last frame received\n");
				else
				    printf(" last frame not received\n");
			}
			return ERR_INCOMPLETE;
		}
	}

	n = recv(sockfd, (char *)&rpkt, sizeof(rpkt), 0);
	if (n == -1) {
		warning("read", "", "");
		return -1;
	}


	/*
	 * Check for format errors.  Bug proofing.
	 */
	if (n < RESP_HEADER_SIZE) {
		if (debug)
		    printf("Short (%d byte) packet received\n", n);
		goto again;
	}
	if (INFO_VERSION(rpkt.rm_vn_mode) > NTP_VERSION ||
	    INFO_VERSION(rpkt.rm_vn_mode) < NTP_OLDVERSION) {
		if (debug)
		    printf("Packet received with version %d\n",
			   INFO_VERSION(rpkt.rm_vn_mode));
		goto again;
	}
	if (INFO_MODE(rpkt.rm_vn_mode) != MODE_PRIVATE) {
		if (debug)
		    printf("Packet received with mode %d\n",
			   INFO_MODE(rpkt.rm_vn_mode));
		goto again;
	}
	if (INFO_IS_AUTH(rpkt.auth_seq)) {
		if (debug)
		    printf("Encrypted packet received\n");
		goto again;
	}
	if (!ISRESPONSE(rpkt.rm_vn_mode)) {
		if (debug)
		    printf("Received request packet, wanted response\n");
		goto again;
	}
	if (INFO_MBZ(rpkt.mbz_itemsize) != 0) {
		if (debug)
		    printf("Received packet with nonzero MBZ field!\n");
		goto again;
	}

	/*
	 * Check implementation/request.  Could be old data getting to us.
	 */
	if (rpkt.implementation != implcode || rpkt.request != reqcode) {
		if (debug)
		    printf(
			    "Received implementation/request of %d/%d, wanted %d/%d",
			    rpkt.implementation, rpkt.request,
			    implcode, reqcode);
		goto again;
	}

	/*
	 * Check the error code.  If non-zero, return it.
	 */
	if (INFO_ERR(rpkt.err_nitems) != INFO_OKAY) {
		if (debug && ISMORE(rpkt.rm_vn_mode)) {
			printf("Error code %d received on not-final packet\n",
			       INFO_ERR(rpkt.err_nitems));
		}
		return (int)INFO_ERR(rpkt.err_nitems);
	}

	/*
	 * Collect items and size.  Make sure they make sense.
	 */
	items = INFO_NITEMS(rpkt.err_nitems);
	size = INFO_ITEMSIZE(rpkt.mbz_itemsize);
	if (esize > size)
		pad = esize - size;
	else 
		pad = 0;
	if ((datasize = items*size) > (n-RESP_HEADER_SIZE)) {
		if (debug)
		    printf(
			    "Received items %d, size %d (total %d), data in packet is %d\n",
			    items, size, datasize, n-RESP_HEADER_SIZE);
		goto again;
	}

	/*
	 * If this isn't our first packet, make sure the size matches
	 * the other ones.
	 */
	if (!firstpkt && esize != *rsize) {
		if (debug)
		    printf("Received itemsize %d, previous %d\n",
			   size, *rsize);
		goto again;
	}
	/*
	 * If we've received this before, +toss it
	 */
	seq = INFO_SEQ(rpkt.auth_seq);
	if (haveseq[seq]) {
		if (debug)
		    printf("Received duplicate sequence number %d\n", seq);
		goto again;
	}
	haveseq[seq] = 1;

	/*
	 * If this is the last in the sequence, record that.
	 */
	if (!ISMORE(rpkt.rm_vn_mode)) {
		if (lastseq != 999) {
			printf("Received second end sequence packet\n");
			goto again;
		}
		lastseq = seq;
	}

	/*
	 * So far, so good.  Copy this data into the output array.
	 */
	if ((datap + datasize + (pad * items)) > (pktdata + pktdatasize)) {
		int offset = datap - pktdata;
		growpktdata();
	        *rdata = pktdata; /* might have been realloced ! */
		datap = pktdata + offset;
	}
	/* 
	 * We now move the pointer along according to size and number of
	 * items.  This is so we can play nice with older implementations
	 */

	tmp_data = (char *)rpkt.data;
	for(i = 0; i <items; i++){
		memmove(datap, tmp_data, (unsigned)size);
		tmp_data += size;
		memset(datap + size, 0, pad);
		datap += size + pad;
	}

	if (firstpkt) {
		firstpkt = 0;
		*rsize = size + pad;
	}
	*ritems += items;

	/*
	 * Finally, check the count of received packets.  If we've got them
	 * all, return
	 */
	++numrecv;
	if (numrecv <= lastseq)
	    goto again;
	return INFO_OKAY;
}


/*
 * sendrequest - format and send a request packet
 */
static int
sendrequest(
	int implcode,
	int reqcode,
	int auth,
	int qitems,
	int qsize,
	char *qdata
	)
{
	struct req_pkt qpkt;
	int datasize;

	memset((char *)&qpkt, 0, sizeof qpkt);

	qpkt.rm_vn_mode = RM_VN_MODE(0, 0, 0);
	qpkt.implementation = (u_char)implcode;
	qpkt.request = (u_char)reqcode;

	datasize = qitems * qsize;
	if (datasize != 0 && qdata != NULL) {
		memmove((char *)qpkt.data, qdata, (unsigned)datasize);
		qpkt.err_nitems = ERR_NITEMS(0, qitems);
		qpkt.mbz_itemsize = MBZ_ITEMSIZE(qsize);
	} else {
		qpkt.err_nitems = ERR_NITEMS(0, 0);
		qpkt.mbz_itemsize = MBZ_ITEMSIZE(0);
	}

	if (!auth) {
		qpkt.auth_seq = AUTH_SEQ(0, 0);
		return sendpkt((char *)&qpkt, req_pkt_size);
	} else {
		l_fp ts;
		int maclen = 0;
		const char *pass = "\0";
		struct req_pkt_tail *qpktail;

		qpktail = (struct req_pkt_tail *)((char *)&qpkt + req_pkt_size
		    + MAX_MAC_LEN - sizeof(struct req_pkt_tail));

		if (info_auth_keyid == 0) {
			if (((struct conf_peer *)qpkt.data)->keyid > 0)
				info_auth_keyid = ((struct conf_peer *)qpkt.data)->keyid;
			else {
				maclen = getkeyid("Keyid: ");
				if (maclen == 0) {
					(void) fprintf(stderr,
					    "Invalid key identifier\n");
					return 1;
				}
				info_auth_keyid = maclen;
			}
		}
		if (!authistrusted(info_auth_keyid)) {
			pass = getpass("MD5 Password: ");
			if (*pass == '\0') {
				(void) fprintf(stderr,
				    "Invalid password\n");
				return (1);
			}
		}
		authusekey(info_auth_keyid, info_auth_keytype, (const u_char *)pass);
		authtrust(info_auth_keyid, 1);
		qpkt.auth_seq = AUTH_SEQ(1, 0);
		qpktail->keyid = htonl(info_auth_keyid);
		get_systime(&ts);
		L_ADD(&ts, &delay_time);
		HTONL_FP(&ts, &qpktail->tstamp);
		maclen = authencrypt(info_auth_keyid, (u_int32 *)&qpkt,
		    req_pkt_size);
		if (maclen == 0) {  
			(void) fprintf(stderr, "Key not found\n");
			return (1);
		}
		return sendpkt((char *)&qpkt, (int)(req_pkt_size + maclen));
	}
	/*NOTREACHED*/
}


/*
 * doquery - send a request and process the response
 */
int
doquery(
	int implcode,
	int reqcode,
	int auth,
	int qitems,
	int qsize,
	char *qdata,
	int *ritems,
	int *rsize,
	char **rdata,
 	int quiet_mask,
	int esize
	)
{
	int res;
	char junk[512];
	fd_set fds;
	struct timeval tvzero;

	/*
	 * Check to make sure host is open
	 */
	if (!havehost) {
		(void) fprintf(stderr, "***No host open, use `host' command\n");
		return -1;
	}

	/*
	 * Poll the socket and clear out any pending data
	 */
again:
	do {
		tvzero.tv_sec = tvzero.tv_usec = 0;
		FD_ZERO(&fds);
		FD_SET(sockfd, &fds);
		res = select(sockfd+1, &fds, (fd_set *)0, (fd_set *)0, &tvzero);

		if (res == -1) {
			warning("polling select", "", "");
			return -1;
		} else if (res > 0)

		    (void) recv(sockfd, junk, sizeof junk, 0);
	} while (res > 0);


	/*
	 * send a request
	 */
	res = sendrequest(implcode, reqcode, auth, qitems, qsize, qdata);
	if (res != 0)
	    return res;
	
	/*
	 * Get the response.  If we got a standard error, print a message
	 */
	res = getresponse(implcode, reqcode, ritems, rsize, rdata, esize);

	/*
	 * Try to be compatible with older implementations of ntpd.
	 */
	if (res == INFO_ERR_FMT && req_pkt_size != 48) {
		int oldsize;

		oldsize = req_pkt_size;

		switch(req_pkt_size) {
		case REQ_LEN_NOMAC:
			req_pkt_size = 160;
			break;
		case 160:
			req_pkt_size = 48;
			break;
		}
		if (impl_ver == IMPL_XNTPD) {
			fprintf(stderr,
			    "***Warning changing to older implementation\n");
			return INFO_ERR_IMPL;
		}

		fprintf(stderr,
		    "***Warning changing the request packet size from %d to %d\n",
		    oldsize, req_pkt_size);
		goto again;
	}

 	/* log error message if not told to be quiet */
 	if ((res > 0) && (((1 << res) & quiet_mask) == 0)) {
		switch(res) {
		    case INFO_ERR_IMPL:
			/* Give us a chance to try the older implementation. */
			if (implcode == IMPL_XNTPD)
				break;
			(void) fprintf(stderr,
				       "***Server implementation incompatable with our own\n");
			break;
		    case INFO_ERR_REQ:
			(void) fprintf(stderr,
				       "***Server doesn't implement this request\n");
			break;
		    case INFO_ERR_FMT:
			(void) fprintf(stderr,
				       "***Server reports a format error in the received packet (shouldn't happen)\n");
			break;
		    case INFO_ERR_NODATA:
			(void) fprintf(stderr,
				       "***Server reports data not found\n");
			break;
		    case INFO_ERR_AUTH:
			(void) fprintf(stderr, "***Permission denied\n");
			break;
		    case ERR_TIMEOUT:
			(void) fprintf(stderr, "***Request timed out\n");
			break;
		    case ERR_INCOMPLETE:
			(void) fprintf(stderr,
				       "***Response from server was incomplete\n");
			break;
		    default:
			(void) fprintf(stderr,
				       "***Server returns unknown error code %d\n", res);
			break;
		}
	}
	return res;
}


/*
 * getcmds - read commands from the standard input and execute them
 */
static void
getcmds(void)
{
#if defined(HAVE_LIBREADLINE) || defined(HAVE_LIBEDIT)
	char *line;

	for (;;) {
		if ((line = readline(interactive?prompt:"")) == NULL) return;
		if (*line) add_history(line);
		docmd(line);
		free(line);
	}
#else /* not (HAVE_LIBREADLINE || HAVE_LIBEDIT) */
	char line[MAXLINE];

	for (;;) {
		if (interactive) {
#ifdef VMS	/* work around a problem with mixing stdout & stderr */
			fputs("",stdout);
#endif
			(void) fputs(prompt, stderr);
			(void) fflush(stderr);
		}

		if (fgets(line, sizeof line, stdin) == NULL)
		    return;

		docmd(line);
	}
#endif /* not HAVE_LIBREADLINE || HAVE_LIBEDIT */
}


#ifndef SYS_WINNT /* Under NT cannot handle SIGINT, WIN32 spawns a handler */
/*
 * abortcmd - catch interrupts and abort the current command
 */
static RETSIGTYPE
abortcmd(
	int sig
	)
{

	if (current_output == stdout)
	    (void) fflush(stdout);
	putc('\n', stderr);
	(void) fflush(stderr);
	if (jump) longjmp(interrupt_buf, 1);
}
#endif /* SYS_WINNT */

/*
 * docmd - decode the command line and execute a command
 */
static void
docmd(
	const char *cmdline
	)
{
	char *tokens[1+MAXARGS+2];
	struct parse pcmd;
	int ntok;
	int i, ti;
	int rval;
	struct xcmd *xcmd;

	ai_fam_templ = ai_fam_default;
	/*
	 * Tokenize the command line.  If nothing on it, return.
	 */
	tokenize(cmdline, tokens, &ntok);
	if (ntok == 0)
	    return;
	
	/*
	 * Find the appropriate command description.
	 */
	i = findcmd(tokens[0], builtins, opcmds, &xcmd);
	if (i == 0) {
		(void) fprintf(stderr, "***Command `%s' unknown\n",
			       tokens[0]);
		return;
	} else if (i >= 2) {
		(void) fprintf(stderr, "***Command `%s' ambiguous\n",
			       tokens[0]);
		return;
	}
	
	/*
	 * Save the keyword, then walk through the arguments, interpreting
	 * as we go.
	 */
	pcmd.keyword = tokens[0];
	pcmd.nargs = 0;
	ti = 1;
	for (i = 0; i < MAXARGS && xcmd->arg[i] != NO;) {
		if ((i+ti) >= ntok) {
			if (!(xcmd->arg[i] & OPT)) {
				printusage(xcmd, stderr);
				return;
			}
			break;
		}
		if ((xcmd->arg[i] & OPT) && (*tokens[i+ti] == '>'))
			break;
		rval = getarg(tokens[i+ti], (int)xcmd->arg[i], &pcmd.argval[i]);
		if (rval == -1) {
			ti++;
			continue;
		}
		if (rval == 0)
			return;
		pcmd.nargs++;
		i++;
	}

	/* Any extra args are assumed to be "OPT|NTP_STR". */
	for ( ; i < MAXARGS + MOREARGS;) {
	     if ((i+ti) >= ntok)
		  break;
		rval = getarg(tokens[i+ti], (int)(OPT|NTP_STR), &pcmd.argval[i]);
		if (rval == -1) {
			ti++;
			continue;
		}
		if (rval == 0)
			return;
		pcmd.nargs++;
		i++;
	}

	i += ti;
	if (i < ntok && *tokens[i] == '>') {
		char *fname;

		if (*(tokens[i]+1) != '\0')
		    fname = tokens[i]+1;
		else if ((i+1) < ntok)
		    fname = tokens[i+1];
		else {
			(void) fprintf(stderr, "***No file for redirect\n");
			return;
		}

		current_output = fopen(fname, "w");
		if (current_output == NULL) {
			(void) fprintf(stderr, "***Error opening %s: ", fname);
			perror("");
			return;
		}
	} else {
		current_output = stdout;
	}

	if (interactive && setjmp(interrupt_buf)) {
		return;
	} else {
		jump = 1;
		(xcmd->handler)(&pcmd, current_output);
		jump = 0;
		if (current_output != stdout)
			(void) fclose(current_output);
		current_output = NULL;
	}
}


/*
 * tokenize - turn a command line into tokens
 */
static void
tokenize(
	const char *line,
	char **tokens,
	int *ntok
	)
{
	register const char *cp;
	register char *sp;
	static char tspace[MAXLINE];

	sp = tspace;
	cp = line;
	for (*ntok = 0; *ntok < MAXTOKENS; (*ntok)++) {
		tokens[*ntok] = sp;
		while (ISSPACE(*cp))
		    cp++;
		if (ISEOL(*cp))
		    break;
		do {
			*sp++ = *cp++;
		} while (!ISSPACE(*cp) && !ISEOL(*cp));

		*sp++ = '\0';
	}
}



/*
 * findcmd - find a command in a command description table
 */
static int
findcmd(
	register char *str,
	struct xcmd *clist1,
	struct xcmd *clist2,
	struct xcmd **cmd
	)
{
	register struct xcmd *cl;
	register int clen;
	int nmatch;
	struct xcmd *nearmatch = NULL;
	struct xcmd *clist;

	clen = strlen(str);
	nmatch = 0;
	if (clist1 != 0)
	    clist = clist1;
	else if (clist2 != 0)
	    clist = clist2;
	else
	    return 0;

    again:
	for (cl = clist; cl->keyword != 0; cl++) {
		/* do a first character check, for efficiency */
		if (*str != *(cl->keyword))