X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/99c91c3aec40b691641374f58e798bd8d6b657bd..60128eebca8c4975a2f1c6a29e16a76f720cc924:/print-ntp.c

diff --git a/print-ntp.c b/print-ntp.c
index ffbdd8f6..ca96236f 100644
--- a/print-ntp.c
+++ b/print-ntp.c
@@ -18,11 +18,12 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * Format and print ntp packets.
  *	By Jeffrey Mogul/DECWRL
  *	loosely based on print-bootp.c
  */
 
+/* \summary: Network Time Protocol (NTP) printer */
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -37,6 +38,8 @@
 #include "addrtoname.h"
 #include "extract.h"
 
+static const char tstr[] = " [|ntp]";
+
 /*
  * Based on ntp.h from the U of MD implementation
  *	This file is based on Version 2 of the NTP spec (RFC1119).
@@ -65,13 +68,13 @@
  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
 struct l_fixedpt {
-	uint32_t int_part;
-	uint32_t fraction;
+	nd_uint32_t int_part;
+	nd_uint32_t fraction;
 };
 
 struct s_fixedpt {
-	uint16_t int_part;
-	uint16_t fraction;
+	nd_uint16_t int_part;
+	nd_uint16_t fraction;
 };
 
 /* rfc2030
@@ -112,20 +115,26 @@ struct s_fixedpt {
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 
-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 message with the mandatory fields ("the header")
+ * and without any optional fields (extension, Key Identifier,
+ * Message Digest).
+ */
+#define NTP_MSG_MINLEN 48
+
+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)
@@ -140,11 +149,14 @@ struct ntpdata {
  */
 #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
@@ -155,7 +167,7 @@ struct ntpdata {
 #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 */
 
 /*
@@ -169,6 +181,7 @@ struct ntpdata {
 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 *, register const int);
 
 static const struct tok ntp_mode_values[] = {
     { MODE_UNSPEC,    "unspecified" },
@@ -177,7 +190,7 @@ static const struct tok ntp_mode_values[] = {
     { MODE_CLIENT,    "Client" },
     { MODE_SERVER,    "Server" },
     { MODE_BROADCAST, "Broadcast" },
-    { MODE_RES1,      "Reserved" },
+    { MODE_CONTROL,   "Control Message" },
     { MODE_RES2,      "Reserved" },
     { 0, NULL }
 };
@@ -196,21 +209,57 @@ static const struct tok ntp_stratum_values[] = {
 	{ 0, NULL }
 };
 
+/* 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
+ */
+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 requests
+ * Print NTP time requests and responses
  */
-void
-ntp_print(netdissect_options *ndo,
-          register const u_char *cp, u_int length)
+static void
+ntp_time_print(netdissect_options *ndo,
+	       register const struct ntp_time_data *bp, u_int length)
 {
-	register const struct ntpdata *bp;
 	int mode, version, leapind;
 
-	bp = (const struct ntpdata *)cp;
+	if (length < NTP_MSG_MINLEN) {
+		ND_PRINT((ndo, "NTP, length %u", length));
+		goto invalid;
+	}
 
 	ND_TCHECK(bp->status);
 
-	version = (int)(bp->status & VERSIONMASK) >> 3;
+	version = (int)(bp->status & VERSIONMASK) >> VERSIONSHIFT;
 	ND_PRINT((ndo, "NTPv%d", version));
 
 	mode = bp->status & MODEMASK;
@@ -236,10 +285,10 @@ ntp_print(netdissect_options *ndo,
 		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));
+	ND_PRINT((ndo, ", poll %d", bp->ppoll));
+	p_poll(ndo, bp->ppoll);
 
-	/* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
-	ND_TCHECK2(bp->root_delay, 0);
+	ND_TCHECK(bp->precision);
 	ND_PRINT((ndo, ", precision %d", bp->precision));
 
 	ND_TCHECK(bp->root_delay);
@@ -275,7 +324,9 @@ ntp_print(netdissect_options *ndo,
 		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((ndo, "0x%08x", EXTRACT_32BITS(&bp->refid)));
 		break;
 	}
 
@@ -301,23 +352,133 @@ ntp_print(netdissect_options *ndo,
 	ND_PRINT((ndo, "\n\t    Originator - Transmit Timestamp: "));
 	p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
 
-	if ( (sizeof(struct ntpdata) - length) == 16) { 	/* Optional: key-id */
+	/* FIXME: this code is not aware of any extension fields */
+	if (length == NTP_MSG_MINLEN + 4) { 	/* Optional: key-id (crypto-NAK) */
 		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_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
+	} else if (length == NTP_MSG_MINLEN + 4 + 16) { 	/* Optional: key-id + 128-bit digest */
 		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\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
+		ND_TCHECK2(bp->message_digest, 16);
                 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)));
-        }
+	} else if (length == NTP_MSG_MINLEN + 4 + 20) { 	/* Optional: key-id + 160-bit digest */
+		ND_TCHECK(bp->key_id);
+		ND_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
+		ND_TCHECK2(bp->message_digest, 20);
+		ND_PRINT((ndo, "\n\tAuthentication: %08x%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),
+		               EXTRACT_32BITS(bp->message_digest + 16)));
+	} else if (length > NTP_MSG_MINLEN) {
+		ND_PRINT((ndo, "\n\t(%u more bytes after the header)", length - NTP_MSG_MINLEN));
+	}
+	return;
+
+invalid:
+	ND_PRINT((ndo, " %s", istr));
+	ND_TCHECK2(*bp, length);
+	return;
+
+trunc:
+	ND_PRINT((ndo, " %s", tstr));
+}
+
+/*
+ * Print NTP control message requests and responses
+ */
+static void
+ntp_control_print(netdissect_options *ndo,
+		  register const struct ntp_control_data *cd, u_int length)
+{
+	u_char R, E, M, opcode;
+	uint16_t sequence, status, assoc, offset, count;
+
+	R = (cd->control & 0x80) != 0;
+	E = (cd->control & 0x40) != 0;
+	M = (cd->control & 0x20) != 0;
+	opcode = cd->control & 0x1f;
+	ND_PRINT((ndo, ", %s, %s, %s, OpCode=%u\n",
+		  R ? "Response" : "Request", E ? "Error" : "OK",
+		  M ? "More" : "Last", (unsigned)opcode));
+
+	sequence = EXTRACT_16BITS(&cd->sequence);
+	ND_PRINT((ndo, "\tSequence=%hu", sequence));
+
+	status = EXTRACT_16BITS(&cd->status);
+	ND_PRINT((ndo, ", Status=%#hx", status));
+
+	assoc = EXTRACT_16BITS(&cd->assoc);
+	ND_PRINT((ndo, ", Assoc.=%hu", assoc));
+
+	offset = EXTRACT_16BITS(&cd->offset);
+	ND_PRINT((ndo, ", Offset=%hu", offset));
+
+	count = EXTRACT_16BITS(&cd->count);
+	ND_PRINT((ndo, ", Count=%hu", count));
+
+	if ((cd->data - (const u_char *)cd) + count > length)
+		goto trunc;
+	if (count != 0)
+		ND_PRINT((ndo, "\n\tTO-BE-DONE: data not interpreted"));
 	return;
 
 trunc:
-	ND_PRINT((ndo, " [|ntp]"));
+	ND_PRINT((ndo, " %s", tstr));
+}
+
+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,
+          register const u_char *cp, u_int length)
+{
+	register const union ntpdata *bp = (const union ntpdata *)cp;
+	int mode, version, leapind;
+
+	ND_TCHECK(bp->td.status);
+
+	version = (bp->td.status & VERSIONMASK) >> VERSIONSHIFT;
+	ND_PRINT((ndo, "NTPv%d", version));
+
+	mode = (bp->td.status & MODEMASK) >> MODESHIFT;
+	if (!ndo->ndo_vflag) {
+		ND_PRINT((ndo, ", %s, length %u",
+		          tok2str(ntp_mode_values, "Unknown mode", mode),
+		          length));
+		return;
+	}
+
+	ND_PRINT((ndo, ", %s, length %u\n",
+	          tok2str(ntp_mode_values, "Unknown mode", mode), length));
+
+	/* leapind = (bp->td.status & LEAPMASK) >> LEAPSHIFT; */
+	leapind = (bp->td.status & LEAPMASK);
+	ND_PRINT((ndo, "\tLeap indicator: %s (%u)",
+	          tok2str(ntp_leapind_values, "Unknown", leapind),
+	          leapind));
+
+	if (mode >= MODE_UNSPEC && mode <= MODE_BROADCAST)
+		ntp_time_print(ndo, &bp->td, length);
+	else if (mode == MODE_CONTROL)
+		ntp_control_print(ndo, &bp->cd, length);
+	else
+		{;}			/* XXX: not implemented! */
+	return;
+
+trunc:
+	ND_PRINT((ndo, " %s", tstr));
 }
 
 static void
@@ -326,12 +487,12 @@ p_sfix(netdissect_options *ndo,
 {
 	register int i;
 	register int f;
-	register float ff;
+	register double ff;
 
 	i = EXTRACT_16BITS(&sfp->int_part);
 	f = EXTRACT_16BITS(&sfp->fraction);
-	ff = f / 65536.0;	/* shift radix point by 16 bits */
-	f = ff * 1000000.0;	/* Treat fraction as parts per million */
+	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));
 }
 
@@ -344,28 +505,29 @@ p_ntp_time(netdissect_options *ndo,
 	register int32_t i;
 	register uint32_t uf;
 	register uint32_t f;
-	register float ff;
+	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 = ff * 1000000000.0;	/* treat fraction as parts per billion */
+	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.
+	 * print the UTC 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);
+	    tm = gmtime(&seconds);
+	    /* use ISO 8601 (RFC3339) format */
+	    strftime(time_buf, sizeof (time_buf), "%Y-%m-%dT%H:%M:%S", tm);
 	    ND_PRINT((ndo, " (%s)", time_buf));
 	}
 #endif
@@ -381,7 +543,7 @@ p_ntp_delta(netdissect_options *ndo,
 	register uint32_t u, uf;
 	register uint32_t ou, ouf;
 	register uint32_t f;
-	register float ff;
+	register double ff;
 	int signbit;
 
 	u = EXTRACT_32BITS(&lfp->int_part);
@@ -419,8 +581,22 @@ p_ntp_delta(netdissect_options *ndo,
 	ff = f;
 	if (ff < 0.0)		/* some compilers are buggy */
 		ff += FMAXINT;
-	ff = ff / FMAXINT;	/* shift radix point by 32 bits */
-	f = ff * 1000000000.0;	/* treat fraction as parts per billion */
+	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));
 }
 
+/* Prints polling interval in log2 as seconds or fraction of second */
+static void
+p_poll(netdissect_options *ndo,
+       register const int poll_interval)
+{
+	if (poll_interval <= -32 || poll_interval >= 32)
+		return;
+
+	if (poll_interval >= 0)
+		ND_PRINT((ndo, " (%us)", 1U << poll_interval));
+	else
+		ND_PRINT((ndo, " (1/%us)", 1U << -poll_interval));
+}
+