The Tcpdump Group git mirrors - tcpdump/blob - print-arista.c

   1 // Copyright (c) 2018 Arista Networks, Inc.  All rights reserved.
   2
   3 /* \summary: EtherType protocol for Arista Networks printer */
   4
   5 #include <config.h>
   6
   7 #include "netdissect-stdinc.h"
   8
   9 #include "netdissect.h"
  10 #include "extract.h"
  11
  12 /*
  13
  14 From Bill Fenner:
  15
  16 The Arista timestamp header consists of the following fields:
  17 1. The Arista ethertype (0xd28b)
  18 2. A 2-byte subtype field; 0x01 indicates the timestamp header
  19 3. A 2-byte version field, described below.
  20 4. A 48-bit or 64-bit timestamp field, depending on the contents of the version field
  21
  22 This header is then followed by the original ethertype and the remainder of the original packet.
  23
  24  0                   1                   2                   3
  25  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
  26 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  27 |                            dst mac                            |
  28 +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  29 |                               |                               |
  30 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
  31 |                            src mac                            |
  32 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33 |        ethertype 0xd28b       |          subtype 0x1          |
  34 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35 |            version            |                               |
  36 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
  37 |                          timestamp...                         |
  38 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  39
  40 The two-byte version value is split into 3 fields:
  41 1. The timescale in use.  Currently assigned values include:
  42     0 = TAI
  43     1 = UTC
  44 2. The timestamp format and length.  Currently assigned values include:
  45     1 = 64-bit timestamp
  46     2 = 48-bit timestamp
  47 3. The hardware info
  48     0 = R/R2 series
  49     1 = R3 series
  50
  51  0                   1
  52  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
  53 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  54 |   timescale   | format|hw info|
  55 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56
  57
  58 See also: https://www.arista.com/assets/data/pdf/Whitepapers/Overview_Arista_Timestamps.pdf
  59
  60 */
  61
  62 #define ARISTA_SUBTYPE_TIMESTAMP 0x0001
  63 static const struct tok subtype_str[] = {
  64         { ARISTA_SUBTYPE_TIMESTAMP, "Timestamp" },
  65         { 0, NULL }
  66 };
  67
  68 static const struct tok ts_timescale_str[] = {
  69         { 0, "TAI" },
  70         { 1, "UTC" },
  71         { 0, NULL }
  72 };
  73
  74 #define FORMAT_64BIT 0x1
  75 #define FORMAT_48BIT 0x2
  76 static const struct tok ts_format_str[] = {
  77         { FORMAT_64BIT, "64-bit" },
  78         { FORMAT_48BIT, "48-bit" },
  79         { 0, NULL }
  80 };
  81
  82 static const struct tok hw_info_str[] = {
  83         { 0, "R/R2" },
  84         { 1, "R3" },
  85         { 0, NULL }
  86 };
  87
  88 #define MAX_VALID_NS 999999999U
  89 #define BOGUS_NS_STR "(bogus ns!)"
  90
  91 static inline void
  92 arista_print_date_hms_time(netdissect_options *ndo, const uint32_t seconds,
  93                 const uint32_t nanoseconds)
  94 {
  95         const time_t ts = seconds;
  96         char buf[sizeof("-yyyyyyyyyy-mm-dd hh:mm:ss")];
  97
  98         ND_PRINT("%s.%09u",
  99             nd_format_time(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S",
 100                gmtime(&ts)), nanoseconds);
 101         if (nanoseconds > MAX_VALID_NS)
 102                 ND_PRINT(" " BOGUS_NS_STR);
 103 }
 104
 105 int
 106 arista_ethertype_print(netdissect_options *ndo, const u_char *bp, u_int len _U_)
 107 {
 108         uint16_t subTypeId;
 109         u_short bytesConsumed = 0;
 110
 111         ndo->ndo_protocol = "arista";
 112
 113         subTypeId = GET_BE_U_2(bp);
 114         bp += 2;
 115         bytesConsumed += 2;
 116
 117         ND_PRINT("SubType %s (0x%04x), ",
 118                  tok2str(subtype_str, "Unknown", subTypeId),
 119                  subTypeId);
 120
 121         // TapAgg Header Timestamping
 122         if (subTypeId == ARISTA_SUBTYPE_TIMESTAMP) {
 123                 uint32_t seconds;
 124                 uint32_t nanoseconds;
 125                 uint8_t ts_timescale = GET_U_1(bp);
 126                 bp += 1;
 127                 bytesConsumed += 1;
 128                 ND_PRINT("Timescale %s (%u), ",
 129                          tok2str(ts_timescale_str, "Unknown", ts_timescale),
 130                          ts_timescale);
 131
 132                 uint8_t ts_format = GET_U_1(bp) >> 4;
 133                 uint8_t hw_info = GET_U_1(bp) & 0x0f;
 134                 bp += 1;
 135                 bytesConsumed += 1;
 136
 137                 // Timestamp has 32-bit lsb in nanosec and remaining msb in sec
 138                 ND_PRINT("Format %s (%u), HwInfo %s (%u), Timestamp ",
 139                          tok2str(ts_format_str, "Unknown", ts_format),
 140                          ts_format,
 141                          tok2str(hw_info_str, "Unknown", hw_info),
 142                          hw_info);
 143                 switch (ts_format) {
 144                 case FORMAT_64BIT:
 145                         seconds = GET_BE_U_4(bp);
 146                         nanoseconds = GET_BE_U_4(bp + 4);
 147                         arista_print_date_hms_time(ndo, seconds, nanoseconds);
 148                         bytesConsumed += 8;
 149                         break;
 150                 case FORMAT_48BIT:
 151                         seconds = GET_BE_U_2(bp);
 152                         nanoseconds = GET_BE_U_4(bp + 2);
 153                         ND_PRINT("%u.%09u", seconds, nanoseconds);
 154                         if (nanoseconds > MAX_VALID_NS)
 155                                 ND_PRINT(" " BOGUS_NS_STR);
 156                         bytesConsumed += 6;
 157                         break;
 158                 default:
 159                         return -1;
 160                 }
 161         } else {
 162                 return -1;
 163         }
 164         ND_PRINT(": ");
 165         return bytesConsumed;
 166 }