DDP

NAME

SYNOPSIS

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

ddp_socket = socket(AF_APPLETALK, SOCK_DGRAM, 0);
raw_socket = socket(AF_APPLETALK, SOCK_RAW, protocol);

DESCRIPTION

The communication between AppleTalk and the user program works using a BSD-compatible socket interface. For more information on sockets, see socket(7).

An AppleTalk socket is created by calling the socket(2) function with a AF_APPLETALK socket family argument. Valid socket types are SOCK_DGRAM to open a ddp socket or SOCK_RAW to open a raw socket. protocol is the AppleTalk protocol to be received or sent. For SOCK_RAW you must specify ATPROTO_DDP.

Raw sockets may be opened only by a process with effective user ID 0 or when the process has the CAP_NET_RAW capability.  

Address format

struct at_addr {
    unsigned short s_net;
    unsigned char  s_node; };

struct sockaddr_atalk {
    sa_family_t    sat_family;    /* address family */
    unsigned char  sat_port;      /* port */
    struct at_addr sat_addr;      /* net/node */ };

sat_family is always set to AF_APPLETALK. sat_port contains the port. The port numbers below 129 are known as reserved ports. Only processes with the effective user ID 0 or the CAP_NET_BIND_SERVICE capability may bind(2) to these sockets. sat_addr is the host address. The net member of struct at_addr contains the host network in network byte order. The value of AT_ANYNET is a wildcard and also implies "this network." The node member of struct at_addr contains the host node number. The value of AT_ANYNODE is a wildcard and also implies "this node." The value of ATADDR_BCAST is a link local broadcast address.  

Socket options

/proc interfaces

aarp-expiry-time

The time interval (in seconds) before an AARP cache entry expires.

aarp-resolve-time

The time interval (in seconds) before an AARP cache entry is resolved.

aarp-retransmit-limit

The number of retransmissions of an AARP query before the node is declared dead.

aarp-tick-time

The timer rate (in seconds) for the timer driving AARP.

The default values match the specification and should never need to be changed.  

Ioctls

ERRORS

EACCES

The user tried to execute an operation without the necessary permissions. These include sending to a broadcast address without having the broadcast flag set, and trying to bind to a reserved port without effective user ID 0 or CAP_NET_BIND_SERVICE.

EADDRINUSE

Tried to bind to an address already in use.

EADDRNOTAVAIL

A nonexistent interface was requested or the requested source address was not local.

EAGAIN

Operation on a nonblocking socket would block.

EALREADY

A connection operation on a nonblocking socket is already in progress.

ECONNABORTED

A connection was closed during an accept(2).

EHOSTUNREACH

No routing table entry matches the destination address.

EINVAL

Invalid argument passed.

EISCONN

connect(2) was called on an already connected socket.

EMSGSIZE

Datagram is bigger than the DDP MTU.

ENODEV

Network device not available or not capable of sending IP.

ENOENT

SIOCGSTAMP was called on a socket where no packet arrived.

ENOMEM and ENOBUFS

Not enough memory available.

ENOPKG

A kernel subsystem was not configured.

ENOPROTOOPT and EOPNOTSUPP

Invalid socket option passed.

ENOTCONN

The operation is defined only on a connected socket, but the socket wasn't connected.

EPERM

User doesn't have permission to set high priority, make a configuration change, or send signals to the requested process or group.

EPIPE

The connection was unexpectedly closed or shut down by the other end.

ESOCKTNOSUPPORT

The socket was unconfigured, or an unknown socket type was requested.

VERSIONS

NOTES

Compatibility

The raw socket mode is unique to Linux and exists to support the alternative CAP package and AppleTalk monitoring tools more easily.  

BUGS

The ioctls used to configure routing tables, devices, AARP tables, and other devices are not yet described.  

SEE ALSO

COLOPHON

Index

NAME

SYNOPSIS

DESCRIPTION

Address format

Socket options

/proc interfaces

Ioctls

ERRORS

VERSIONS

NOTES

Compatibility

BUGS

SEE ALSO

COLOPHON