shithub: 9ferno

ref: 6966e8d72ae8fb72ebf98909acbd464aff84a3cc

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.TH ETHER 3
.SH NAME
ether \- Ethernet device
.SH SYNOPSIS
.nf
.BI "bind -a #l" n " /net"

.BI /net/ether n /clone
.BI /net/ether n /[0-7]
.BI /net/ether n /[0-7]/data
.BI /net/ether n /[0-7]/ctl
.BI /net/ether n /[0-7]/stats
.BI /net/ether n /[0-7]/type
.BI /net/ether n /[0-7]/ifstats
.fi
.SH DESCRIPTION
The Ethernet device
.BI #l n
serves a three-level directory representing a physical Ethernet interface:
AMD LANCE, 3Com 3C509, 3Com 3C905, Intel 82557, and others.
If
.I n
is not given it is taken to be 0.
.PP
The top level directory
has a single directory named
.BI ether n,
where
.I n
is the interface number, starting from 0,
assigned in some platform-dependent way.
That directory contains a conversation directory for each of 8 Ethernet packet types,
and a
.B clone
file.
.PP
Opening the
.B clone
file returns a file descriptor open on the
.B ctl
file of an unused conversation directory.
Reading the
.B ctl
file returns a text
string representing the number of the
connection.
The connection is controlled by writing textual commands to the associated
.B ctl
file:
.TP
.BI connect " type"
Set the
.I type
of Ethernet packets received on the connection; the type is
expressed
as an integer constant
(in hexadecimal if it has a leading
.BR 0x ,
octal if it has a leading
.BR 0 ,
and otherwise decimal).
For instance, Ethernet packets carrying IP version 4 use type
.BR 0x800 .
The value
.B \-1
stands for all types.
The value
.B \-2
causes at most the first 64 bytes of all types of packets to be copied
to the conversation.
If several conversations are assigned the same packet type,
a copy of the packet is given to each.
.TP
.B promiscuous
Set the interface to capture all packets regardless of destination address.
An interface normally receives only packets whose 
destination address is that of the interface or is the
broadcast address,
.BR ffffffffffff .
The interface remains promiscuous until the control file is
closed.
The extra packets are received only by conversations of the same type
as the incoming packet (or of type -1).
.TP
.BI addmulti " address"
Add the given MAC multicast
.I address
to the set of multicast addresses accepted by the interface.
.I Address
is a twelve digit MAC address in hexadecimal.
.TP
.BI remmulti " address"
Remove
.I address
from the set of multicast addresses accepted by the interface.
.PP
Incoming Ethernet packets are demultiplexed by destination address and
packet type and queued
for reading by the corresponding open connection(s).
Each read of the
.B data
file returns each packet in turn, including the Ethernet header.
A read will terminate at packet boundaries.
Each write to the
.B data
file causes a packet to be sent.
The Ethernet address of the interface is inserted into
the packet header as the source address.
.PP
Reading the
.B type
file returns the decimal value of the assigned Ethernet packet type.
.PP
Reading the
.B stats
file returns status information, the value
of counters, the `promiscuous' state,
and the Ethernet MAC address of the
interface.
.PP
Reading the
.B ifstats
file returns statistics and status information specific to a given
hardware interface.
.SH SOURCE
.B /os/port/devlance.c
.br
.B /os/port/netif.c
.br
.B /os/*/devether.c
.br
.B /os/*/ether*.c
.SH SEE ALSO
.IR ip (3)