Upgrade tcpdump to tcpdump-4.99.1

Test: make
Change-Id: I052ed8f5279c806e4d2ff925f581b71db3ac03c0
diff --git a/print-ntp.c b/print-ntp.c
index 0689264..99c0896 100644
--- a/print-ntp.c
+++ b/print-ntp.c
@@ -24,11 +24,19 @@
 
 /* \summary: Network Time Protocol (NTP) printer */
 
+/*
+ * specification:
+ *
+ * RFC 1119 - NTPv2
+ * RFC 1305 - NTPv3
+ * RFC 5905 - NTPv4
+ */
+
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
 #endif
 
-#include <netdissect-stdinc.h>
+#include "netdissect-stdinc.h"
 
 #ifdef HAVE_STRFTIME
 #include <time.h>
@@ -38,43 +46,13 @@
 #include "addrtoname.h"
 #include "extract.h"
 
+#include "ntp.h"
+
 /*
  * Based on ntp.h from the U of MD implementation
  *	This file is based on Version 2 of the NTP spec (RFC1119).
  */
 
-/*
- *  Definitions for the masses
- */
-#define	JAN_1970	2208988800U	/* 1970 - 1900 in seconds */
-
-/*
- * Structure definitions for NTP fixed point values
- *
- *    0			  1		      2			  3
- *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
- *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- *   |			       Integer Part			     |
- *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- *   |			       Fraction Part			     |
- *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- *
- *    0			  1		      2			  3
- *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
- *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- *   |		  Integer Part	     |	   Fraction Part	     |
- *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-*/
-struct l_fixedpt {
-	uint32_t int_part;
-	uint32_t fraction;
-};
-
-struct s_fixedpt {
-	uint16_t int_part;
-	uint16_t fraction;
-};
-
 /* rfc2030
  *                      1                   2                   3
  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
@@ -113,20 +91,26 @@
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 
-struct ntpdata {
-	u_char status;		/* status of local clock and leap info */
-	u_char stratum;		/* Stratum level */
-	u_char ppoll;		/* poll value */
-	int precision:8;
+/* Length of the NTP data message with the mandatory fields ("the header")
+ * and without any optional fields (extension, Key Identifier,
+ * Message Digest).
+ */
+#define NTP_TIMEMSG_MINLEN 48U
+
+struct ntp_time_data {
+	nd_uint8_t status;		/* status of local clock and leap info */
+	nd_uint8_t stratum;		/* Stratum level */
+	nd_int8_t ppoll;		/* poll value */
+	nd_int8_t precision;
 	struct s_fixedpt root_delay;
 	struct s_fixedpt root_dispersion;
-	uint32_t refid;
+	nd_uint32_t refid;
 	struct l_fixedpt ref_timestamp;
 	struct l_fixedpt org_timestamp;
 	struct l_fixedpt rec_timestamp;
 	struct l_fixedpt xmt_timestamp;
-        uint32_t key_id;
-        uint8_t  message_digest[16];
+	nd_uint32_t key_id;
+	nd_uint8_t  message_digest[20];
 };
 /*
  *	Leap Second Codes (high order two bits)
@@ -141,11 +125,14 @@
  */
 #define	NTPVERSION_1	0x08
 #define	VERSIONMASK	0x38
+#define	VERSIONSHIFT	3
 #define LEAPMASK	0xc0
+#define LEAPSHIFT	6
 #ifdef MODEMASK
 #undef MODEMASK					/* Solaris sucks */
 #endif
 #define	MODEMASK	0x07
+#define	MODESHIFT	0
 
 /*
  *	Code values
@@ -156,7 +143,7 @@
 #define	MODE_CLIENT	3	/* client */
 #define	MODE_SERVER	4	/* server */
 #define	MODE_BROADCAST	5	/* broadcast */
-#define	MODE_RES1	6	/* reserved */
+#define	MODE_CONTROL	6	/* control message */
 #define	MODE_RES2	7	/* reserved */
 
 /*
@@ -168,8 +155,8 @@
 #define	INFO_REPLY	63	/* **** THIS implementation dependent **** */
 
 static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
-static void p_ntp_time(netdissect_options *, const struct l_fixedpt *);
 static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
+static void p_poll(netdissect_options *, const int);
 
 static const struct tok ntp_mode_values[] = {
     { MODE_UNSPEC,    "unspecified" },
@@ -178,7 +165,7 @@
     { MODE_CLIENT,    "Client" },
     { MODE_SERVER,    "Server" },
     { MODE_BROADCAST, "Broadcast" },
-    { MODE_RES1,      "Reserved" },
+    { MODE_CONTROL,   "Control Message" },
     { MODE_RES2,      "Reserved" },
     { 0, NULL }
 };
@@ -197,217 +184,327 @@
 	{ 0, NULL }
 };
 
-/*
- * Print ntp requests
+/* draft-ietf-ntp-mode-6-cmds-02
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |LI |  VN |Mode |R|E|M| OpCode  |       Sequence Number         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |            Status             |       Association ID          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |            Offset             |            Count              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * /                    Data (up to 468 bytes)                     /
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                    Padding (optional)                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * /              Authenticator (optional, 96 bytes)               /
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ *               Figure 1: NTP Control Message Header
  */
-void
-ntp_print(netdissect_options *ndo,
-          register const u_char *cp, u_int length)
+
+/* Length of the NTP control message with the mandatory fields ("the header")
+ * and without any optional fields (Data, Padding, Authenticator).
+ */
+#define NTP_CTRLMSG_MINLEN 12U
+
+struct ntp_control_data {
+	nd_uint8_t	magic;		/* LI, VN, Mode */
+	nd_uint8_t	control;	/* R, E, M, OpCode */
+	nd_uint16_t	sequence;	/* Sequence Number */
+	nd_uint16_t	status;		/* Status */
+	nd_uint16_t	assoc;		/* Association ID */
+	nd_uint16_t	offset;		/* Offset */
+	nd_uint16_t	count;		/* Count */
+	nd_uint8_t	data[564];	/* Data, [Padding, [Authenticator]] */
+};
+
+/*
+ * Print NTP time requests and responses
+ */
+static void
+ntp_time_print(netdissect_options *ndo,
+	       const struct ntp_time_data *bp, u_int length)
 {
-	register const struct ntpdata *bp;
-	int mode, version, leapind;
+	uint8_t stratum;
 
-	bp = (const struct ntpdata *)cp;
+	if (length < NTP_TIMEMSG_MINLEN)
+		goto invalid;
 
-	ND_TCHECK(bp->status);
+	stratum = GET_U_1(bp->stratum);
+	ND_PRINT(", Stratum %u (%s)",
+		stratum,
+		tok2str(ntp_stratum_values, (stratum >=2 && stratum<=15) ? "secondary reference" : "reserved", stratum));
 
-	version = (int)(bp->status & VERSIONMASK) >> 3;
-	ND_PRINT((ndo, "NTPv%d", version));
+	ND_PRINT(", poll %d", GET_S_1(bp->ppoll));
+	p_poll(ndo, GET_S_1(bp->ppoll));
 
-	mode = bp->status & MODEMASK;
-	if (!ndo->ndo_vflag) {
-		ND_PRINT((ndo, ", %s, length %u",
-		          tok2str(ntp_mode_values, "Unknown mode", mode),
-		          length));
-		return;
-	}
+	ND_PRINT(", precision %d", GET_S_1(bp->precision));
 
-	ND_PRINT((ndo, ", length %u\n\t%s",
-	          length,
-	          tok2str(ntp_mode_values, "Unknown mode", mode)));
-
-	leapind = bp->status & LEAPMASK;
-	ND_PRINT((ndo, ", Leap indicator: %s (%u)",
-	          tok2str(ntp_leapind_values, "Unknown", leapind),
-	          leapind));
-
-	ND_TCHECK(bp->stratum);
-	ND_PRINT((ndo, ", Stratum %u (%s)",
-		bp->stratum,
-		tok2str(ntp_stratum_values, (bp->stratum >=2 && bp->stratum<=15) ? "secondary reference" : "reserved", bp->stratum)));
-
-	ND_TCHECK(bp->ppoll);
-	ND_PRINT((ndo, ", poll %u (%us)", bp->ppoll, 1 << bp->ppoll));
-
-	/* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
-	ND_TCHECK2(bp->root_delay, 0);
-	ND_PRINT((ndo, ", precision %d", bp->precision));
-
-	ND_TCHECK(bp->root_delay);
-	ND_PRINT((ndo, "\n\tRoot Delay: "));
+	ND_TCHECK_SIZE(&bp->root_delay);
+	ND_PRINT("\n\tRoot Delay: ");
 	p_sfix(ndo, &bp->root_delay);
 
-	ND_TCHECK(bp->root_dispersion);
-	ND_PRINT((ndo, ", Root dispersion: "));
+	ND_TCHECK_SIZE(&bp->root_dispersion);
+	ND_PRINT(", Root dispersion: ");
 	p_sfix(ndo, &bp->root_dispersion);
 
-	ND_TCHECK(bp->refid);
-	ND_PRINT((ndo, ", Reference-ID: "));
+	ND_TCHECK_4(bp->refid);
+	ND_PRINT(", Reference-ID: ");
 	/* Interpretation depends on stratum */
-	switch (bp->stratum) {
+	switch (stratum) {
 
 	case UNSPECIFIED:
-		ND_PRINT((ndo, "(unspec)"));
+		ND_PRINT("(unspec)");
 		break;
 
 	case PRIM_REF:
-		if (fn_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
+		if (nd_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
 			goto trunc;
 		break;
 
 	case INFO_QUERY:
-		ND_PRINT((ndo, "%s INFO_QUERY", ipaddr_string(ndo, &(bp->refid))));
+		ND_PRINT("%s INFO_QUERY", GET_IPADDR_STRING(bp->refid));
 		/* this doesn't have more content */
 		return;
 
 	case INFO_REPLY:
-		ND_PRINT((ndo, "%s INFO_REPLY", ipaddr_string(ndo, &(bp->refid))));
+		ND_PRINT("%s INFO_REPLY", GET_IPADDR_STRING(bp->refid));
 		/* this is too complex to be worth printing */
 		return;
 
 	default:
-		ND_PRINT((ndo, "%s", ipaddr_string(ndo, &(bp->refid))));
+		/* In NTPv4 (RFC 5905) refid is an IPv4 address or first 32 bits of
+		   MD5 sum of IPv6 address */
+		ND_PRINT("0x%08x", GET_BE_U_4(bp->refid));
 		break;
 	}
 
-	ND_TCHECK(bp->ref_timestamp);
-	ND_PRINT((ndo, "\n\t  Reference Timestamp:  "));
+	ND_TCHECK_SIZE(&bp->ref_timestamp);
+	ND_PRINT("\n\t  Reference Timestamp:  ");
 	p_ntp_time(ndo, &(bp->ref_timestamp));
 
-	ND_TCHECK(bp->org_timestamp);
-	ND_PRINT((ndo, "\n\t  Originator Timestamp: "));
+	ND_TCHECK_SIZE(&bp->org_timestamp);
+	ND_PRINT("\n\t  Originator Timestamp: ");
 	p_ntp_time(ndo, &(bp->org_timestamp));
 
-	ND_TCHECK(bp->rec_timestamp);
-	ND_PRINT((ndo, "\n\t  Receive Timestamp:    "));
+	ND_TCHECK_SIZE(&bp->rec_timestamp);
+	ND_PRINT("\n\t  Receive Timestamp:    ");
 	p_ntp_time(ndo, &(bp->rec_timestamp));
 
-	ND_TCHECK(bp->xmt_timestamp);
-	ND_PRINT((ndo, "\n\t  Transmit Timestamp:   "));
+	ND_TCHECK_SIZE(&bp->xmt_timestamp);
+	ND_PRINT("\n\t  Transmit Timestamp:   ");
 	p_ntp_time(ndo, &(bp->xmt_timestamp));
 
-	ND_PRINT((ndo, "\n\t    Originator - Receive Timestamp:  "));
+	ND_PRINT("\n\t    Originator - Receive Timestamp:  ");
 	p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
 
-	ND_PRINT((ndo, "\n\t    Originator - Transmit Timestamp: "));
+	ND_PRINT("\n\t    Originator - Transmit Timestamp: ");
 	p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
 
-	if ( (sizeof(struct ntpdata) - length) == 16) { 	/* Optional: key-id */
-		ND_TCHECK(bp->key_id);
-		ND_PRINT((ndo, "\n\tKey id: %u", bp->key_id));
-	} else if ( (sizeof(struct ntpdata) - length) == 0) { 	/* Optional: key-id + authentication */
-		ND_TCHECK(bp->key_id);
-		ND_PRINT((ndo, "\n\tKey id: %u", bp->key_id));
-		ND_TCHECK2(bp->message_digest, sizeof (bp->message_digest));
-                ND_PRINT((ndo, "\n\tAuthentication: %08x%08x%08x%08x",
-        		       EXTRACT_32BITS(bp->message_digest),
-		               EXTRACT_32BITS(bp->message_digest + 4),
-		               EXTRACT_32BITS(bp->message_digest + 8),
-		               EXTRACT_32BITS(bp->message_digest + 12)));
-        }
+	/* FIXME: this code is not aware of any extension fields */
+	if (length == NTP_TIMEMSG_MINLEN + 4) { 	/* Optional: key-id (crypto-NAK) */
+		ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
+	} else if (length == NTP_TIMEMSG_MINLEN + 4 + 16) { 	/* Optional: key-id + 128-bit digest */
+		ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
+		ND_TCHECK_LEN(bp->message_digest, 16);
+		ND_PRINT("\n\tAuthentication: %08x%08x%08x%08x",
+			 GET_BE_U_4(bp->message_digest),
+			 GET_BE_U_4(bp->message_digest + 4),
+			 GET_BE_U_4(bp->message_digest + 8),
+			 GET_BE_U_4(bp->message_digest + 12));
+	} else if (length == NTP_TIMEMSG_MINLEN + 4 + 20) { 	/* Optional: key-id + 160-bit digest */
+		ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
+		ND_TCHECK_LEN(bp->message_digest, 20);
+		ND_PRINT("\n\tAuthentication: %08x%08x%08x%08x%08x",
+			 GET_BE_U_4(bp->message_digest),
+			 GET_BE_U_4(bp->message_digest + 4),
+			 GET_BE_U_4(bp->message_digest + 8),
+			 GET_BE_U_4(bp->message_digest + 12),
+			 GET_BE_U_4(bp->message_digest + 16));
+	} else if (length > NTP_TIMEMSG_MINLEN) {
+		ND_PRINT("\n\t(%u more bytes after the header)", length - NTP_TIMEMSG_MINLEN);
+	}
+	return;
+
+invalid:
+	nd_print_invalid(ndo);
+	ND_TCHECK_LEN(bp, length);
 	return;
 
 trunc:
-	ND_PRINT((ndo, " [|ntp]"));
+	nd_print_trunc(ndo);
+}
+
+/*
+ * Print NTP control message requests and responses
+ */
+static void
+ntp_control_print(netdissect_options *ndo,
+		  const struct ntp_control_data *cd, u_int length)
+{
+	uint8_t control, R, E, M, opcode;
+	uint16_t sequence, status, assoc, offset, count;
+
+	if (length < NTP_CTRLMSG_MINLEN)
+		goto invalid;
+
+	control = GET_U_1(cd->control);
+	R = (control & 0x80) != 0;
+	E = (control & 0x40) != 0;
+	M = (control & 0x20) != 0;
+	opcode = control & 0x1f;
+	ND_PRINT(", %s, %s, %s, OpCode=%u\n",
+		  R ? "Response" : "Request", E ? "Error" : "OK",
+		  M ? "More" : "Last", opcode);
+
+	sequence = GET_BE_U_2(cd->sequence);
+	ND_PRINT("\tSequence=%hu", sequence);
+
+	status = GET_BE_U_2(cd->status);
+	ND_PRINT(", Status=%#hx", status);
+
+	assoc = GET_BE_U_2(cd->assoc);
+	ND_PRINT(", Assoc.=%hu", assoc);
+
+	offset = GET_BE_U_2(cd->offset);
+	ND_PRINT(", Offset=%hu", offset);
+
+	count = GET_BE_U_2(cd->count);
+	ND_PRINT(", Count=%hu", count);
+
+	if (NTP_CTRLMSG_MINLEN + count > length)
+		goto invalid;
+	if (count != 0) {
+		ND_TCHECK_LEN(cd->data, count);
+		ND_PRINT("\n\tTO-BE-DONE: data not interpreted");
+	}
+	return;
+
+invalid:
+	nd_print_invalid(ndo);
+	ND_TCHECK_LEN(cd, length);
+	return;
+
+trunc:
+	nd_print_trunc(ndo);
+}
+
+union ntpdata {
+	struct ntp_time_data	td;
+	struct ntp_control_data	cd;
+};
+
+/*
+ * Print NTP requests, handling the common VN, LI, and Mode
+ */
+void
+ntp_print(netdissect_options *ndo,
+	  const u_char *cp, u_int length)
+{
+	const union ntpdata *bp = (const union ntpdata *)cp;
+	u_int mode, version, leapind;
+	uint8_t status;
+
+	ndo->ndo_protocol = "ntp";
+	status = GET_U_1(bp->td.status);
+
+	version = (status & VERSIONMASK) >> VERSIONSHIFT;
+	ND_PRINT("NTPv%u", version);
+
+	mode = (status & MODEMASK) >> MODESHIFT;
+	if (!ndo->ndo_vflag) {
+		ND_PRINT(", %s, length %u",
+			 tok2str(ntp_mode_values, "Unknown mode", mode),
+			 length);
+		return;
+	}
+
+	ND_PRINT(", %s, length %u\n",
+		  tok2str(ntp_mode_values, "Unknown mode", mode), length);
+
+	/* leapind = (status & LEAPMASK) >> LEAPSHIFT; */
+	leapind = (status & LEAPMASK);
+	ND_PRINT("\tLeap indicator: %s (%u)",
+		 tok2str(ntp_leapind_values, "Unknown", leapind),
+		 leapind);
+
+	switch (mode) {
+
+	case MODE_UNSPEC:
+	case MODE_SYM_ACT:
+	case MODE_SYM_PAS:
+	case MODE_CLIENT:
+	case MODE_SERVER:
+	case MODE_BROADCAST:
+		ntp_time_print(ndo, &bp->td, length);
+		break;
+
+	case MODE_CONTROL:
+		ntp_control_print(ndo, &bp->cd, length);
+		break;
+
+	default:
+		break;			/* XXX: not implemented! */
+	}
 }
 
 static void
 p_sfix(netdissect_options *ndo,
-       register const struct s_fixedpt *sfp)
+       const struct s_fixedpt *sfp)
 {
-	register int i;
-	register int f;
-	register double ff;
+	int i;
+	int f;
+	double ff;
 
-	i = EXTRACT_16BITS(&sfp->int_part);
-	f = EXTRACT_16BITS(&sfp->fraction);
+	i = GET_BE_U_2(sfp->int_part);
+	f = GET_BE_U_2(sfp->fraction);
 	ff = f / 65536.0;		/* shift radix point by 16 bits */
 	f = (int)(ff * 1000000.0);	/* Treat fraction as parts per million */
-	ND_PRINT((ndo, "%d.%06d", i, f));
-}
-
-#define	FMAXINT	(4294967296.0)	/* floating point rep. of MAXINT */
-
-static void
-p_ntp_time(netdissect_options *ndo,
-           register const struct l_fixedpt *lfp)
-{
-	register int32_t i;
-	register uint32_t uf;
-	register uint32_t f;
-	register double ff;
-
-	i = EXTRACT_32BITS(&lfp->int_part);
-	uf = EXTRACT_32BITS(&lfp->fraction);
-	ff = uf;
-	if (ff < 0.0)		/* some compilers are buggy */
-		ff += FMAXINT;
-	ff = ff / FMAXINT;			/* shift radix point by 32 bits */
-	f = (uint32_t)(ff * 1000000000.0);	/* treat fraction as parts per billion */
-	ND_PRINT((ndo, "%u.%09d", i, f));
-
-#ifdef HAVE_STRFTIME
-	/*
-	 * print the time in human-readable format.
-	 */
-	if (i) {
-	    time_t seconds = i - JAN_1970;
-	    struct tm *tm;
-	    char time_buf[128];
-
-	    tm = localtime(&seconds);
-	    strftime(time_buf, sizeof (time_buf), "%Y/%m/%d %H:%M:%S", tm);
-	    ND_PRINT((ndo, " (%s)", time_buf));
-	}
-#endif
+	ND_PRINT("%d.%06d", i, f);
 }
 
 /* Prints time difference between *lfp and *olfp */
 static void
 p_ntp_delta(netdissect_options *ndo,
-            register const struct l_fixedpt *olfp,
-            register const struct l_fixedpt *lfp)
+	    const struct l_fixedpt *olfp,
+	    const struct l_fixedpt *lfp)
 {
-	register int32_t i;
-	register uint32_t u, uf;
-	register uint32_t ou, ouf;
-	register uint32_t f;
-	register double ff;
+	uint32_t u, uf;
+	uint32_t ou, ouf;
+	uint32_t i;
+	uint32_t f;
+	double ff;
 	int signbit;
 
-	u = EXTRACT_32BITS(&lfp->int_part);
-	ou = EXTRACT_32BITS(&olfp->int_part);
-	uf = EXTRACT_32BITS(&lfp->fraction);
-	ouf = EXTRACT_32BITS(&olfp->fraction);
+	u = GET_BE_U_4(lfp->int_part);
+	ou = GET_BE_U_4(olfp->int_part);
+	uf = GET_BE_U_4(lfp->fraction);
+	ouf = GET_BE_U_4(olfp->fraction);
 	if (ou == 0 && ouf == 0) {
 		p_ntp_time(ndo, lfp);
 		return;
 	}
 
-	i = u - ou;
-
-	if (i > 0) {		/* new is definitely greater than old */
+	if (u > ou) {		/* new is definitely greater than old */
 		signbit = 0;
+		i = u - ou;
 		f = uf - ouf;
 		if (ouf > uf)	/* must borrow from high-order bits */
 			i -= 1;
-	} else if (i < 0) {	/* new is definitely less than old */
+	} else if (u < ou) {	/* new is definitely less than old */
 		signbit = 1;
+		i = ou - u;
 		f = ouf - uf;
-		if (uf > ouf)	/* must carry into the high-order bits */
-			i += 1;
-		i = -i;
+		if (uf > ouf)	/* must borrow from the high-order bits */
+			i -= 1;
 	} else {		/* int_part is zero */
+		i = 0;
 		if (uf > ouf) {
 			signbit = 0;
 			f = uf - ouf;
@@ -422,6 +519,20 @@
 		ff += FMAXINT;
 	ff = ff / FMAXINT;			/* shift radix point by 32 bits */
 	f = (uint32_t)(ff * 1000000000.0);	/* treat fraction as parts per billion */
-	ND_PRINT((ndo, "%s%d.%09d", signbit ? "-" : "+", i, f));
+	ND_PRINT("%s%u.%09u", signbit ? "-" : "+", i, f);
+}
+
+/* Prints polling interval in log2 as seconds or fraction of second */
+static void
+p_poll(netdissect_options *ndo,
+       const int poll_interval)
+{
+	if (poll_interval <= -32 || poll_interval >= 32)
+		return;
+
+	if (poll_interval >= 0)
+		ND_PRINT(" (%us)", 1U << poll_interval);
+	else
+		ND_PRINT(" (1/%us)", 1U << -poll_interval);
 }