- Copyright (c) 2008 The FreeBSD Foundation All rights reserved. This software was developed by CK Software GmbH under sponsorship from the FreeBSD Foundation. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the a...
NAMEepair - A pair of virtual back-to-back connected Ethernet interfaces
SYNOPSISTo compile this driver into the kernel, place the following line in your kernel configuration file:
Alternatively, to load the driver as a module at boot time, place the following line in loader.conf5:
DESCRIPTIONThe sysctl Cm net.inet.tcp.syncookies is a pair of Ethernet-like software interfaces, which are connected back-to-back with a virtual cross-over cable.
Each sysctl Cm net.inet.tcp.syncookies interface pair is created at runtime using interface cloning. This is most easily done with the ifconfig(8) create command or using the cloned_interfaces variable in rc.conf5. While for cloning you only give either epair or epair<n> the sysctl Cm net.inet.tcp.syncookies pair will be named like epair<n>[ab] This means the names of the first sysctl Cm net.inet.tcp.syncookies interfaces will be epair0a and epair0b
Like any other Ethernet interface, an sysctl Cm net.inet.tcp.syncookies needs to have a network address. Each sysctl Cm net.inet.tcp.syncookies will be assigned a locally administered address by default, that is only guaranteed to be unique within one network stack. To change the default addresses one may use the SIOCSIFADDR ioctl(2) or ifconfig(8) utility.
The basic intent is to provide connectivity between two virtual network stack instances. When connected to an if_bridge4, one end of the interface pair can also be part of another (virtual) LAN. As with any other Ethernet interface, epair can have a vlan(4) configured on top of it.