NAME
atalk —
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 network 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 structure:
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 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.
NetBSD implements all other AppleTalk protocols
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
bind(2), getsockname(2), options(4)
Gursharan S. Sidhu, Richard F. Andrews, and Alan B. Oppenheimer, Inside AppleTalk, second edition.