NAME    [Toc]    [Back]

     atalk - AppleTalk Protocol Family

SYNOPSIS    [Toc]    [Back]

     #include <sys/types.h>
     #include <netatalk/at.h>

DESCRIPTION    [Toc]    [Back]

     The AppleTalk Protocol Family  provides  presentation  layer
support for the
     AppleTalk   Datagram  Delivery  Protocol  (DDP),  using  the
SOCK_DGRAM socket
     type.  In addition, access to  in-kernel  AppleTalk  routing
tables and network
 interface configurations is provided.

     The AppleTalk Protocol Suite provides support for four kinds
of physical
     media: LocalTalk (230kbps wire-or'd serial), Ethernet, Token
Ring, and
     asynchronous  serial connections (using either AppleTalk Remote Access
     (ARA) or PPP).   Currently,  this  AppleTalk  implementation
supports only
     Ethernet.

     AppleTalk packets are encapsulated on the Ethernet using the
EtherTalk
     Link Access Protocol (ELAP).  Local network address  resolution is handled
     using  the  AppleTalk  Address  Resolution  Protocol (AARP).
Neither of these
     protocols is exposed to user-mode applications.

ADDRESSING    [Toc]    [Back]

     AppleTalk addresses are three  byte  quantities,  stored  in
network byte order.
  The include file <netatalk/at.h> defines the AppleTalk
address format.


     Sockets in the AppleTalk protocol family use  the  following
address structure:


           struct sockaddr_at {
                   u_int8_t        sat_len;
                   u_int8_t        sat_family;
                   u_int8_t        sat_port;
                   struct at_addr  sat_addr;
                   union {
                           struct netrange r_netrange;
                           char            r_zero[8];
                   } sat_range;
           };

     The  port of a socket may be set with bind(2).  The node for
bind(2) must
     always be ATADDR_ANYNODE: ``this node.''  The  net  must  be
ATADDR_ANYNET.
     ATADDR_ANYNET  corresponds  to the machine's ``primary'' address (the first
     configured).  The port of a socket and the  primary  address
are returned
     with getsockname(2).

PROTOCOLS    [Toc]    [Back]

     The  AppleTalk protocol family is comprised of the DDP datagram delivery
     protocol, AppleTalk Data Stream Protocol  (ADSP),  AppleTalk
Echo Protocol
     (AEP),  AppleTalk  Filing  Protocol (AFP), AppleTalk Session
Protocol (ASP),
     AppleTalk Transaction Protocol (ATP), Name Binding  Protocol
(NBP), Printer
  Access  Protocol  (PAP),  and  Zone Information Protocol
(ZIP).

     DDP is implemented in the kernel as  SOCK_DGRAM  sockets  in
the
     AF_APPLETALK  address family.  All other AppleTalk protocols
are implemented
 using the Netatalk package.  Netatalk implements  all
functions except
 for ADSP and an AFP client.  AEP, NBP, and ZIP services
are provided
     by the atalkd daemon.  ASP and ATP services are provided  by
a user library.
   PAP  and AFP services are provided by user programs
and daemons.

SEE ALSO    [Toc]    [Back]

     bind(2), getsockname(2)

     Gursharan S. Sidhu, Richard F. Andrews, and Alan  B.  Oppenheimer, Inside
     AppleTalk, second edition.

OpenBSD      3.6                        November     14,     1997