.TH ETHER 3 .SH NAMEether \- Ethernet device.SH SYNOPSIS.nf.B bind -a #l\fIn\fP /net .BI /net/ether n /clone.BI /net/ether n /addr.BI /net/ether n /mtu.BI /net/ether n /ifstats.BI /net/ether n /stats.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]/ifstats.BI /net/ether n /[0-7]/stats.BI /net/ether n /[0-7]/type.fi.SH DESCRIPTIONThe Ethernet interface,.BI /net/ether n\f1,is a directorycontaining subdirectories, one for each distinct Ethernet packet type,and.BR clone ,.BR addr ,.BR mtu ,.BR ifstats ,and.B statsfiles..B statsand.B ifstatsare the same as in the subdirectories (see below).Reading.B addrreturns the MAC address of this interface in hex with no punctuationand no trailing newline.  Reading.B mtureturns 3 12-byte numbers: the hardware's minimum MTU, the currentMTU and the maximum MTU supported by the interface.  The MTUis set by writing.B mtu.I ninto the.B ctlfile.The number.I n(optional in the bind)is the device number of the card, permitting multiple cards to be used on a single machine..PPEach directory contains files to control the associated connection,receive and send data,and supply statistics.Incoming Ethernet packets are demultiplexed by packet type and passed upthe corresponding open connection.Reading from the.B datafile reads packets of that type arriving from the network.A read will terminate at packet boundaries.Each write to the.B datafile causes a packet to be sent.The Ethernet address of the interface is inserted intothe packet header as the source address unless.B l2bridgeis set..PPA connection is assigned to a packet type by opening its.B ctlfile andwriting .B connect.I nwhere.I nis a decimal integer constant identifying the Ethernet packet type.A type of \-1 enables the connection to receive copies of packets ofall types.  A type of \-2 enables the connection to receive copies ofthe first 64 bytes of packets of all types.If multiple connections are assigned to a given packet typea copy of each packet is passed up each connection..PPSome interfaces also accept unique options when written to the.I ctl(or.IR clone )file; see the description of.I wavelanin.IR plan9.ini (8).The control messages described in.IR ip (3)under.B "Configuring interfaces"from.L bridgeto.L headersonlyare understood.The additional control message.L nonblockingmakes.I writesystems calls to this interface non-blocking ifffollowed by nothing or a non-zero integer;a following.L 0makes.I writesblock on a full output queue..PPReading the.B ctlfile returns the decimal index of the associated connection, 0 through 7.Reading the.B typefile returns the decimal value of the assigned Ethernet packet type.Reading the.B statsfile returns status information such as the Ethernet address of thecard and general statistics, independent of the interface;.B ifstatscontains device-specific data and statistics about the card.The format of the.B statsfile is.IB stat : value ...\fR.In particular, if.B linkis non-zero,.B mbpsis the current speed of the interface inmegabits-per-second.  While.B inand.B outare the total number of packets input or outputand do differ (in the case of dropped packets orloop back) from hardware counters..PPAn interface normally receives only those packets whose destination address is that of the interface, thebroadcast address,.BR ff:ff:ff:ff:ff:ff ,or a a multicast address assigned to the interface.Multicast addresses are added by writing.B addmulti.I eaand remove by writing.B remmulti.I eato the.B ctlfile.  Multicast addresses are automatically dropped whenthe connection is closed.The interface can be made to receive all packets on thenetwork by writing the string .B promiscuousto the.B ctlfile. The interface remains promiscuous until the control file isclosed by all connections requesting promiscuous mode.The extra packets are passed up connections of types \-1and \-2 only..PPWriting.B bridgeto the.B ctlfile causes loop back packets to be ignored.  This is useful forlayer 3 bridging.  Writing.B l2bridgealso allows the connection to set the source address andreceive packets with any destination address.Writing.B scanbs[.I secs]starts a scan for wireless base stations and sets thescanning interval to.IR secs.Scanning is terminated when the connection is closed.The default interval is 5s.  For wired connections, this command is ignored..SH SOURCE.B /sys/src/9/*/devether.c.br.B /sys/src/9/port/netif.c.SH "SEE ALSO".IR ip (3)..SH BUGSThe multicast interface makes removal of multicastaddresses on that rely on hashing difficult..PPInterface MTU settings must be greater than thoseused by.IR ip (3);this is not enforced.  NB: interface MTU is differentthan IP stack's MTU.