linux/include
David Ahern 3f2fb9a834 net: l3mdev: address selection should only consider devices in L3 domain
David Lamparter noted a use case where the source address selection fails
to pick an address from a VRF interface - unnumbered interfaces.

Relevant commands from his script:
    ip addr add 9.9.9.9/32 dev lo
    ip link set lo up

    ip link add name vrf0 type vrf table 101
    ip rule add oif vrf0 table 101
    ip rule add iif vrf0 table 101
    ip link set vrf0 up
    ip addr add 10.0.0.3/32 dev vrf0

    ip link add name dummy2 type dummy
    ip link set dummy2 master vrf0 up

    --> note dummy2 has no address - unnumbered device

    ip route add 10.2.2.2/32 dev dummy2 table 101
    ip neigh add 10.2.2.2 dev dummy2 lladdr 02:00:00:00:00:02

    tcpdump -ni dummy2 &

And using ping instead of his socat example:
    $ ping -I vrf0 -c1 10.2.2.2
    ping: Warning: source address might be selected on device other than vrf0.
    PING 10.2.2.2 (10.2.2.2) from 9.9.9.9 vrf0: 56(84) bytes of data.

>From tcpdump:
    12:57:29.449128 IP 9.9.9.9 > 10.2.2.2: ICMP echo request, id 2491, seq 1, length 64

Note the source address is from lo and is not a VRF local address. With
this patch:

    $ ping -I vrf0 -c1 10.2.2.2
    PING 10.2.2.2 (10.2.2.2) from 10.0.0.3 vrf0: 56(84) bytes of data.

>From tcpdump:
    12:59:25.096426 IP 10.0.0.3 > 10.2.2.2: ICMP echo request, id 2113, seq 1, length 64

Now the source address comes from vrf0.

The ipv4 function for selecting source address takes a const argument.
Removing the const requires touching a lot of places, so instead
l3mdev_master_ifindex_rcu is changed to take a const argument and then
do the typecast to non-const as required by netdev_master_upper_dev_get_rcu.
This is similar to what l3mdev_fib_table_rcu does.

IPv6 for unnumbered interfaces appears to be selecting the addresses
properly.

Cc: David Lamparter <david@opensourcerouting.org>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-26 14:22:26 -05:00
..
acpi ACPI / CPPC: remove redundant mbox_send_message() declaration 2016-02-03 01:09:52 +01:00
asm-generic powerpc fixes for 4.5 #2 2016-02-20 09:22:11 -08:00
clocksource
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-01-22 11:58:43 -08:00
drm drm/atomic: Allow for holes in connector state, v2. 2016-02-19 13:24:03 +10:00
dt-bindings clk: tegra: Add the APB2APE audio clock on Tegra210 2016-02-02 15:49:29 +01:00
keys
kvm
linux net: ethtool: remove unused __ethtool_get_settings 2016-02-25 22:06:47 -05:00
math-emu
media [media] vb2: fix nasty vb2_thread regression 2016-02-04 09:13:46 -02:00
memory
misc
net net: l3mdev: address selection should only consider devices in L3 domain 2016-02-26 14:22:26 -05:00
pcmcia
ras
rdma net: rdma: use __ethtool_get_ksettings 2016-02-25 22:06:46 -05:00
rxrpc
scsi Initial roundup of 4.5 merge window patches 2016-01-23 18:45:06 -08:00
soc ARM: SoC driver updates for v4.5 2016-01-20 18:42:30 -08:00
sound ALSA: rawmidi: Make snd_rawmidi_transmit() race-free 2016-02-03 14:51:28 +01:00
target target/transport: add flag to indicate CPU Affinity is observed 2016-02-10 23:08:55 -08:00
trace sunvnet: Add support for perf LDC event tracing 2016-02-07 14:13:05 -05:00
uapi net: ethtool: add new ETHTOOL_xLINKSETTINGS API 2016-02-25 22:06:45 -05:00
video
xen Merge branch 'for-4.5/drivers' of git://git.kernel.dk/linux-block 2016-01-21 18:19:38 -08:00
Kbuild