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