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 #ifdef HAVE_CONFIG_H
   6 #include <config.h>
   7 #endif
   8
   9 #include "netdissect-stdinc.h"
  10
  11 #include "netdissect.h"
  12 #include "extract.h"
  13
  14 /*
  15
  16 From Bill Fenner:
  17
  18 The Arista timestamp header consists of the following fields:
  19 1. The Arista ethertype (0xd28b)
  20 2. A 2-byte subtype field; 0x01 indicates the timestamp header
  21 3. A 2-byte version field, described below.
  22 4. A 48-bit or 64-bit timestamp field, depending on the contents of the version field
  23
  24 This header is then followed by the original ethertype and the remainder of the original packet.
  25
  26  0                   1                   2                   3
  27  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
  28 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  29 |                            dst mac                            |
  30 +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  31 |                               |                               |
  32 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
  33 |                            src mac                            |
  34 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35 |        ethertype 0xd28b       |          subtype 0x1          |
  36 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37 |            version            |                               |
  38 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
  39 |                          timestamp...                         |
  40 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41
  42 The two-byte version value is split into 3 fields:
  43 1. The timescale in use.  Currently assigned values include:
  44     0 = TAI
  45     1 = UTC
  46 2. The timestamp format and length.  Currently assigned values include:
  47     1 = 64-bit timestamp
  48     2 = 48-bit timestamp
  49 3. The hardware info
  50     0 = R/R2 series
  51     1 = R3 series
  52
  53  0                   1
  54  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
  55 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56 |   timescale   | format|hw info|
  57 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  58
  59
  60 See also: https://www.arista.com/assets/data/pdf/Whitepapers/Overview_Arista_Timestamps.pdf
  61
  62 */
  63
  64 #define ARISTA_SUBTYPE_TIMESTAMP 0x0001
  65 static const struct tok subtype_str[] = {
  66         { ARISTA_SUBTYPE_TIMESTAMP, "Timestamp" },
  67         { 0, NULL }
  68 };
  69
  70 static const struct tok ts_timescale_str[] = {
  71         { 0, "TAI" },
  72         { 1, "UTC" },
  73         { 0, NULL }
  74 };
  75
  76 #define FORMAT_64BIT 0x1
  77 #define FORMAT_48BIT 0x2
  78 static const struct tok ts_format_str[] = {
  79         { FORMAT_64BIT, "64-bit" },
  80         { FORMAT_48BIT, "48-bit" },
  81         { 0, NULL }
  82 };
  83
  84 static const struct tok hw_info_str[] = {
  85         { 0, "R/R2" },
  86         { 1, "R3" },
  87         { 0, NULL }
  88 };
  89
  90 #define MAX_VALID_NS 999999999U
  91 #define BOGUS_NS_STR "(bogus ns!)"
  92
  93 static inline void
  94 arista_print_date_hms_time(netdissect_options *ndo, const uint32_t seconds,
  95                 const uint32_t nanoseconds)
  96 {
  97         const time_t ts = seconds;
  98         char buf[sizeof("-yyyyyyyyyy-mm-dd hh:mm:ss")];
  99
 100         ND_PRINT("%s.%09u",
 101             nd_format_time(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S",
 102                gmtime(&ts)), nanoseconds);
 103         if (nanoseconds > MAX_VALID_NS)
 104                 ND_PRINT(" " BOGUS_NS_STR);
 105 }
 106
 107 int
 108 arista_ethertype_print(netdissect_options *ndo, const u_char *bp, u_int len _U_)
 109 {
 110         uint16_t subTypeId;
 111         u_short bytesConsumed = 0;
 112
 113         ndo->ndo_protocol = "arista";
 114
 115         subTypeId = GET_BE_U_2(bp);
 116         bp += 2;
 117         bytesConsumed += 2;
 118
 119         ND_PRINT("SubType %s (0x%04x), ",
 120                  tok2str(subtype_str, "Unknown", subTypeId),
 121                  subTypeId);
 122
 123         // TapAgg Header Timestamping
 124         if (subTypeId == ARISTA_SUBTYPE_TIMESTAMP) {
 125                 uint32_t seconds;
 126                 uint32_t nanoseconds;
 127                 uint8_t ts_timescale = GET_U_1(bp);
 128                 bp += 1;
 129                 bytesConsumed += 1;
 130                 ND_PRINT("Timescale %s (%u), ",
 131                          tok2str(ts_timescale_str, "Unknown", ts_timescale),
 132                          ts_timescale);
 133
 134                 uint8_t ts_format = GET_U_1(bp) >> 4;
 135                 uint8_t hw_info = GET_U_1(bp) & 0x0f;
 136                 bp += 1;
 137                 bytesConsumed += 1;
 138
 139                 // Timestamp has 32-bit lsb in nanosec and remaining msb in sec
 140                 ND_PRINT("Format %s (%u), HwInfo %s (%u), Timestamp ",
 141                          tok2str(ts_format_str, "Unknown", ts_format),
 142                          ts_format,
 143                          tok2str(hw_info_str, "Unknown", hw_info),
 144                          hw_info);
 145                 switch (ts_format) {
 146                 case FORMAT_64BIT:
 147                         seconds = GET_BE_U_4(bp);
 148                         nanoseconds = GET_BE_U_4(bp + 4);
 149                         arista_print_date_hms_time(ndo, seconds, nanoseconds);
 150                         bytesConsumed += 8;
 151                         break;
 152                 case FORMAT_48BIT:
 153                         seconds = GET_BE_U_2(bp);
 154                         nanoseconds = GET_BE_U_4(bp + 2);
 155                         ND_PRINT("%u.%09u", seconds, nanoseconds);
 156                         if (nanoseconds > MAX_VALID_NS)
 157                                 ND_PRINT(" " BOGUS_NS_STR);
 158                         bytesConsumed += 6;
 159                         break;
 160                 default:
 161                         return -1;
 162                 }
 163         } else {
 164                 return -1;
 165         }
 166         ND_PRINT(": ");
 167         return bytesConsumed;
 168 }