ATALK(4) BSD Kernel Interfaces Manual ATALK(4)NAMEatalk — AppleTalk Protocol Family
SYNOPSIS
#include <sys/types.h>
#include <netatalk/at.h>
DESCRIPTION
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 net‐
work interface configurations is provided.
The AppleTalk Protocol Suite provides support for five kinds of physical
media: LocalTalk (230kbps wire-or'd serial), Ethernet, FDDI, Token Ring,
and asynchronous serial connections (using either AppleTalk Remote Access
(ARA) or PPP ). Currently, NetBSD's AppleTalk implementation supports
Ethernet, FDDI, and Token Ring.
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
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 struc‐
ture:
struct sockaddr_at {
uint8_t sat_len;
sa_family_t sat_family;
uint8_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
The AppleTalk protocol family comprises the DDP datagram delivery proto‐
col, 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. NetBSD implements all other AppleTalk pro‐
tocols using the Netatalk package. Netatalk implements all functions
except for ADSP and an AFP client. AEP, NBP, and ZIP services are pro‐
vided 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 ALSObind(2), getsockname(2), options(4)
Gursharan S. Sidhu, Richard F. Andrews, and Alan B. Oppenheimer, Inside
AppleTalk, second edition.
BSD November 14, 1997 BSD
