Merge tag 'mmc-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc

[sfrench/cifs-2.6.git] / Documentation / networking / vrf.txt

diff --git a/Documentation/networking/vrf.txt b/Documentation/networking/vrf.txt
index 8ff7b4c8f91bc45da4f4c50792e0dc5587b62875..a5f103b083a0a02f6e33f79c3fe7f90da24aa589 100644 (file)
--- a/Documentation/networking/vrf.txt
+++ b/Documentation/networking/vrf.txt
@@ -103,19 +103,33 @@ VRF device:
 
 or to specify the output device using cmsg and IP_PKTINFO.
 
+By default the scope of the port bindings for unbound sockets is
+limited to the default VRF. That is, it will not be matched by packets
+arriving on interfaces enslaved to an l3mdev and processes may bind to
+the same port if they bind to an l3mdev.
+
 TCP & UDP services running in the default VRF context (ie., not bound
 to any VRF device) can work across all VRF domains by enabling the
 tcp_l3mdev_accept and udp_l3mdev_accept sysctl options:
+
     sysctl -w net.ipv4.tcp_l3mdev_accept=1
     sysctl -w net.ipv4.udp_l3mdev_accept=1
 
+These options are disabled by default so that a socket in a VRF is only
+selected for packets in that VRF. There is a similar option for RAW
+sockets, which is enabled by default for reasons of backwards compatibility.
+This is so as to specify the output device with cmsg and IP_PKTINFO, but
+using a socket not bound to the corresponding VRF. This allows e.g. older ping
+implementations to be run with specifying the device but without executing it
+in the VRF. This option can be disabled so that packets received in a VRF
+context are only handled by a raw socket bound to the VRF, and packets in the
+default VRF are only handled by a socket not bound to any VRF:
+
+    sysctl -w net.ipv4.raw_l3mdev_accept=0
+
 netfilter rules on the VRF device can be used to limit access to services
 running in the default VRF context as well.
 
-The default VRF does not have limited scope with respect to port bindings.
-That is, if a process does a wildcard bind to a port in the default VRF it
-owns the port across all VRF domains within the network namespace.
-
 ################################################################################
 
 Using iproute2 for VRFs