Tim Stallard a9a851f0ec net: ipv6: do not consider routes via gateways for anycast address check ... [ Upstream commit 03e2a984b6 ] The behaviour for what is considered an anycast address changed in commit 45e4fd2668 ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception"). This now considers the first address in a subnet where there is a route via a gateway to be an anycast address. This breaks path MTU discovery and traceroutes when a host in a remote network uses the address at the start of a prefix (eg 2600:: advertised as 2600::/48 in the DFZ) as ICMP errors will not be sent to anycast addresses. This patch excludes any routes with a gateway, or via point to point links, like the behaviour previously from rt6_is_gw_or_nonexthop in net/ipv6/route.c. This can be tested with: ip link add v1 type veth peer name v2 ip netns add test ip netns exec test ip link set lo up ip link set v2 netns test ip link set v1 up ip netns exec test ip link set v2 up ip addr add 2001:db8::1/64 dev v1 nodad ip addr add 2001:db8:100:: dev lo nodad ip netns exec test ip addr add 2001:db8::2/64 dev v2 nodad ip netns exec test ip route add unreachable 2001:db8:1::1 ip netns exec test ip route add 2001:db8:100::/64 via 2001:db8::1 ip netns exec test sysctl net.ipv6.conf.all.forwarding=1 ip route add 2001:db8:1::1 via 2001:db8::2 ping -I 2001:db8::1 2001:db8:1::1 -c1 ping -I 2001:db8:100:: 2001:db8:1::1 -c1 ip addr delete 2001:db8:100:: dev lo ip netns delete test Currently the first ping will get back a destination unreachable ICMP error, but the second will never get a response, with "icmp6_send: acast source" logged. After this patch, both get destination unreachable ICMP replies. Fixes: 45e4fd2668 ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception") Signed-off-by: Tim Stallard <code@timstallard.me.uk> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-04-21 09:04:45 +02:00
..
acpi	ACPICA: Allow acpi_any_gpe_status_set() to skip one GPE	2020-04-17 10:50:09 +02:00
asm-generic	lib/vdso: Make __arch_update_vdso_data() logic understandable	2020-03-05 16:43:49 +01:00
clocksource
crypto	crypto: algif_skcipher - Use chunksize instead of blocksize	2020-01-17 19:48:46 +01:00
drm	drm: mst: Fix query_payload ack reply struct	2019-12-31 16:42:19 +01:00
dt-bindings	clk: imx8mn: Fix incorrect clock defines	2020-03-18 07:17:55 +01:00
keys
kvm
linux	xarray: Fix early termination of xas_for_each_marked	2020-04-17 10:50:18 +02:00
math-emu
media	media: rc: add keymap for Videostrong KII Pro	2020-04-17 10:49:59 +02:00
misc
net	net: ipv6: do not consider routes via gateways for anycast address check	2020-04-21 09:04:45 +02:00
pcmcia
ras
rdma	IB/core: Let IB core distribute cache update events	2020-02-24 08:36:26 +01:00
scsi	scsi: Revert "target: iscsi: Wait for all commands to finish before freeing a session"	2020-02-28 17:22:25 +01:00
soc
sound	ALSA: rawmidi: Avoid bit fields for state flags	2020-02-28 17:22:27 +01:00
target
trace	afs: Fix some tracing details	2020-04-01 11:02:08 +02:00
uapi	include/uapi/linux/swab.h: fix userspace breakage, use __BITS_PER_LONG for swap	2020-04-13 10:48:12 +02:00
vdso
video
xen	xen: fixes and cleanups for 5.4-rc2	2019-10-04 11:13:09 -07:00