Author: bdubbs
Date: 2006-07-29 21:11:25 -0600 (Sat, 29 Jul 2006)
New Revision: 7711
Modified:
branches/6.2/BOOK/chapter07/network.xml
Log:
Update discussion of network driver rules
Modified: branches/6.2/BOOK/chapter07/network.xml
===================================================================
--- branches/6.2/BOOK/chapter07/network.xml 2006-07-30 02:33:23 UTC (rev
7710)
+++ branches/6.2/BOOK/chapter07/network.xml 2006-07-30 03:11:25 UTC (rev
7711)
@@ -49,16 +49,10 @@
Udev rules similar to the following:</para>
<screen role="nodump"><userinput>cat > /etc/udev/rules.d/26-network.rules
<< "EOF"
-<literal>ACTION=="add", SUBSYSTEM=="net", DRIVER=="?*",
SYSFS{address}=="<replaceable>00:e0:4c:12:34:56</replaceable>",
NAME="<replaceable>realtek</replaceable>"
-ACTION=="add", SUBSYSTEM=="net", DRIVER=="?*",
SYSFS{address}=="<replaceable>00:a0:c9:78:9a:bc</replaceable>",
NAME="<replaceable>intel</replaceable>"</literal>
+<literal>ACTION=="add", SUBSYSTEM=="net",
SYSFS{address}=="<replaceable>00:e0:4c:12:34:56</replaceable>",
NAME="<replaceable>realtek</replaceable>"
+ACTION=="add", SUBSYSTEM=="net",
SYSFS{address}=="<replaceable>00:a0:c9:78:9a:bc</replaceable>",
NAME="<replaceable>intel</replaceable>"</literal>
EOF</userinput></screen>
- <para>The DRIVER=="?*" key prevents Udev from attempting to rename 8021Q
- VLAN interfaces (not available without the Vlan package from
- <ulink url="http://www.candelatech.com/~greear/vlan/"/>).
- This is necessary since VLANs have the same MAC address as
- the real network card.</para>
-
<!-- Yes, I know that VLANs are beyond BLFS. This is not the reason to get them
incorrect by default when every distro does this right. -->
@@ -79,6 +73,30 @@
of <quote>eth0</quote> in the network interface configuration files
below.</para>
+ <para>Note that the rules above don't work for every setup. For example,
+ MAC-based rules break when bridges or VLANs are used, because bridges and
+ VLANs have the same MAC address as the network card. One wants to rename
+ only the network card interface, not the bridge or VLAN interface, but the
+ example rule matches both. If you use such virtual interfaces, you have two
+ potential solutions. One is to add the DRIVER=="?*" key after
+ SUBSYSTEM=="net" in MAC-based rules which will stop matching the virtual
+ interfaces. This is known to fail with some older Ethernet cards because
+ they don't have the DRIVER variable in the uevent and thus the rule does
+ not match with such cards. Another solution is to switch to rules that use
+ the bus position as a key.</para>
+
+ <para>The second known non-working case is with wireless cards using the
+ MadWifi or HostAP drivers, because they create at least two interfaces
+ with the same MAC address and bus position. For example, the Madwifi driver
+ creates both an athX and a wifiX interface where X is a digit. To
+ disambiguate these cases, add SYSFS{type}=="zzz" after SUBSYSTEM=="net" for
+ each interface that is handled by that driver, where zzz is the output of
+ <userinput>cat
/sys/class/net/<interface_name>/type</userinput>.</para>
+
+ <para>There may be other cases where the rules above don't work. Currently,
+ bugs on this topic are still being reported to Linux distributions, and no
+ solution that covers every case is available.</para>
+
</sect2>
<sect2>
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