Copyright (c) 2004 Tom Rhodes All rights reserved. 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 above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other m...
NAMEcm - SMC Arcnet Ethernet device driver
SYNOPSISTo compile this driver into the kernel, place the following lines in your kernel configuration file:
device isa device cm
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 driver provides support for the Arcnet ISA network adapters.
This driver also has quirks preset in the device.hints5 file for card detection.
HARDWAREThe sysctl Cm net.inet.tcp.syncookies driver supports the following card models:
- SMC90c66 in '56 compatibility mode.
IMPLEMENTATION NOTESWhen the NOARP flag is set on the sysctl Cm net.inet.tcp.syncookies interface, it does not employ the address resolution protocol described in arp(4) to dynamically map between Internet and Ethernet addresses on the local network. Instead it uses the least significant 8 bits of the IP address as the hardware address like described in RFC 1051 and RFC 1201.
With the IFF_LINK0 flag cleared IP/ARP/RARP encoding is done according to RFC 1201 that is, with Packet Header Definition Standard header and packet type 212 / 213. The MTU is normally 1500. The IFF_LINK0 flag is cleared by default.
With the IFF_LINK0 flag set, IP and ARP encoding is done according to the deprecated RFC 1051 encoding, that is with simple header, packet type 240 / 241, and the MTU is 507.
When switching between the two modes, use
ifconfig interfacename down upto switch the MTU
DIAGNOSTICSThe following driver specific error messages may be reported:
- "reset: card reset, link addr = 0x%02x (cm%d)"
- The card is being reset and a new link address assigned.
- "srint: restarted rx on buf cm%d"
- The rx buffer has been emptied and will be reset.
SEE ALSOnetintro(4), watchdog(4), device.hints5, ifconfig(8), watchdog(8)
HISTORYThe sysctl Cm net.inet.tcp.syncookies device was ported from Nx by An Max Khon Aq Mt fjoe@FreeBSD.org and first appeared in Fx 4.6 . This manual page first appeared in Fx 5.3 .
AUTHORSThis manual page was written by An Tom Rhodes Aq Mt trhodes@FreeBSD.org . The Sx IMPLEMENTATION NOTES section was submitted by An Max Khon Aq Mt fjoe@FreeBSD.org and originated from Nx .
BUGSThe sysctl Cm net.inet.tcp.syncookies driver code could do with a bit of improvement, it would be nice if some one could come along and take care of this.
The Sx IMPLEMENTATION NOTES section is specific to all Arcnet devices (see sys/net/if_arcsubr.c and should be moved to a more generic location.