doc/protocol.texi

   1 @node  Zebra Protocol
   2 @appendix Zebra Protocol
   3 @appendixsection Overview of the Zebra Protocol
   4
   5 Zebra Protocol is used by protocol daemons to communicate with the
   6 zebra daemon.
   7
   8 Each protocol daemon may request and send information to and from the
   9 zebra daemon such as interface states, routing state,
  10 nexthop-validation, and so on. Protocol daemons may also install routes
  11 with zebra. The zebra daemon manages which route is installed into the
  12 forwarding table with the kernel.
  13
  14 Zebra Protocol is a streaming protocol, with a common header. Two
  15 versions of the header are in use. Version 0 is implicitely versioned.
  16 Version 1 has an explicit version field. Version 0 can be distinguished
  17 from all other versions by examining the 3rd byte of the header, which
  18 contains a marker value for all versions bar version 0. The marker byte
  19 corresponds to the command field in version 0, and the marker value is
  20 a reserved command in version 0.
  21
  22 We do not anticipate there will be further versions of the header for
  23 the foreseeable future, as the command field in version 1 is wide
  24 enough to allow for future extensions to done compatibly through
  25 seperate commands.
  26
  27 Version 0 is used by all versions of GNU Zebra as of this writing, and
  28 versions of Quagga up to and including Quagga 0.98. Version 2 was created
  29 for 0.99.21 of Quagga.  Version 3 designates VRF compatibility and was
  30 released in 1.0. Version 4 will be used as of Frr 2.0 to indicate that
  31 we are a different Routing Suite now and to hopefully prevent accidental
  32 Quagga <-> FRR issues.
  33
  34 @appendixsection Zebra Protocol Definition
  35 @appendixsubsec Zebra Protocol Header (version 0)
  36 @example
  37 @group
  38 0                   1                   2                   3
  39 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
  40 +-------------------------------+---------------+
  41 |           Length (2)          |   Command (1) |
  42 +-------------------------------+---------------+
  43 @end group
  44 @end example
  45
  46 @appendixsubsec Zebra Protocol Common Header (version 1)
  47 @example
  48 @group
  49 0                   1                   2                   3
  50 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
  51 +-------------------------------+---------------+-------------+
  52 |           Length (2)          |   Marker (1)  | Version (1) |
  53 +-------------------------------+---------------+-------------+
  54 |          Command (2)          |
  55 +-------------------------------+
  56 @end group
  57 @end example
  58
  59 @appendixsubsec Zebra Protocol Header Field Definitions
  60 @table @samp
  61 @item Length
  62 Total packet length including this header. The minimum length is 3
  63 bytes for version 0 messages and 6 bytes for version 1 messages.
  64
  65 @item Marker
  66 Static marker with a value of 255 always. This is to allow version 0
  67 Zserv headers (which do not include version explicitely) to be
  68 distinguished from versioned headers. Not present in version 0
  69 messages.
  70
  71 @item Version
  72 Version number of the Zserv message. Clients should not continue
  73 processing messages past the version field for versions they do not
  74 recognise. Not present in version 0 messages.
  75
  76 @item Command
  77 The Zebra Protocol command.
  78 @end table
  79
  80 @appendixsubsec Zebra Protocol Commands
  81 @multitable {ZEBRA_REDISTRIBUTE_DEFAULT_DELETE_WHATEVER} {99999}
  82 @headitem Command @tab Value
  83 @item ZEBRA_INTERFACE_ADD
  84 @tab 1
  85 @item ZEBRA_INTERFACE_DELETE
  86 @tab 2
  87 @item ZEBRA_INTERFACE_ADDRESS_ADD
  88 @tab 3
  89 @item ZEBRA_INTERFACE_ADDRESS_DELETE
  90 @tab 4
  91 @item ZEBRA_INTERFACE_UP
  92 @tab 5
  93 @item ZEBRA_INTERFACE_DOWN
  94 @tab 6
  95 @item ZEBRA_IPV4_ROUTE_ADD
  96 @tab 7
  97 @item ZEBRA_IPV4_ROUTE_DELETE
  98 @tab 8
  99 @item ZEBRA_IPV6_ROUTE_ADD
 100 @tab 9
 101 @item ZEBRA_IPV6_ROUTE_DELETE
 102 @tab 10
 103 @item ZEBRA_REDISTRIBUTE_ADD
 104 @tab 11
 105 @item ZEBRA_REDISTRIBUTE_DELETE
 106 @tab 12
 107 @item ZEBRA_REDISTRIBUTE_DEFAULT_ADD
 108 @tab 13
 109 @item ZEBRA_REDISTRIBUTE_DEFAULT_DELETE
 110 @tab 14
 111 @item ZEBRA_IPV4_NEXTHOP_LOOKUP
 112 @tab 15
 113 @item ZEBRA_IPV6_NEXTHOP_LOOKUP
 114 @tab 16
 115 @end multitable