Similar to the previous patch, but covering the dst field:
the slow_gro flag is additionally set when a dst is attached
to the skb
RFC -> v1:
- use the existing flag instead of adding a new one
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move generic blackhole dst ops to the core and use them from both
ipv4_dst_blackhole_ops and ip6_dst_blackhole_ops where possible. No
functional change otherwise. We need these also in other locations
and having to define them over and over again is not great.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch avoids the indirect call for the common case:
ip6_dst_check and ipv4_dst_check
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch avoids the indirect call for the common case:
ip6_mtu and ipv4_mtu
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch avoids the indirect call for the common case:
ip6_output and ip_output
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch avoids the indirect call for the common case:
ip_local_deliver and ip6_input
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 394de110a7 ("net: Added pointer check for
dst->ops->neigh_lookup in dst_neigh_lookup_skb") added a test in
dst_neigh_lookup_skb() to avoid a NULL pointer dereference. The root
cause was the MPLS forwarding code, which doesn't call skb_dst_drop()
on incoming packets. That is, if the packet is received from a
collect_md device, it has a metadata_dst attached to it that doesn't
implement any dst_ops function.
To align the MPLS behaviour with IPv4 and IPv6, let's drop the dst in
mpls_forward(). This way, dst_neigh_lookup_skb() doesn't need to test
->neigh_lookup any more. Let's keep a WARN condition though, to
document the precondition and to ease detection of such problems in the
future.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Link: https://lore.kernel.org/r/f8c2784c13faa54469a2aac339470b1049ca6b63.1604102750.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is a pure codestyle cleanup patch. No functional change intended.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It's currently possible to bridge Ethernet tunnels carrying IP
packets directly to external interfaces without assigning them
addresses and routes on the bridged network itself: this is the case
for UDP tunnels bridged with a standard bridge or by Open vSwitch.
PMTU discovery is currently broken with those configurations, because
the encapsulation effectively decreases the MTU of the link, and
while we are able to account for this using PMTU discovery on the
lower layer, we don't have a way to relay ICMP or ICMPv6 messages
needed by the sender, because we don't have valid routes to it.
On the other hand, as a tunnel endpoint, we can't fragment packets
as a general approach: this is for instance clearly forbidden for
VXLAN by RFC 7348, section 4.3:
VTEPs MUST NOT fragment VXLAN packets. Intermediate routers may
fragment encapsulated VXLAN packets due to the larger frame size.
The destination VTEP MAY silently discard such VXLAN fragments.
The same paragraph recommends that the MTU over the physical network
accomodates for encapsulations, but this isn't a practical option for
complex topologies, especially for typical Open vSwitch use cases.
Further, it states that:
Other techniques like Path MTU discovery (see [RFC1191] and
[RFC1981]) MAY be used to address this requirement as well.
Now, PMTU discovery already works for routed interfaces, we get
route exceptions created by the encapsulation device as they receive
ICMP Fragmentation Needed and ICMPv6 Packet Too Big messages, and
we already rebuild those messages with the appropriate MTU and route
them back to the sender.
Add the missing bits for bridged cases:
- checks in skb_tunnel_check_pmtu() to understand if it's appropriate
to trigger a reply according to RFC 1122 section 3.2.2 for ICMP and
RFC 4443 section 2.4 for ICMPv6. This function is already called by
UDP tunnels
- a new function generating those ICMP or ICMPv6 replies. We can't
reuse icmp_send() and icmp6_send() as we don't see the sender as a
valid destination. This doesn't need to be generic, as we don't
cover any other type of ICMP errors given that we only provide an
encapsulation function to the sender
While at it, make the MTU check in skb_tunnel_check_pmtu() accurate:
we might receive GSO buffers here, and the passed headroom already
includes the inner MAC length, so we don't have to account for it
a second time (that would imply three MAC headers on the wire, but
there are just two).
This issue became visible while bridging IPv6 packets with 4500 bytes
of payload over GENEVE using IPv4 with a PMTU of 4000. Given the 50
bytes of encapsulation headroom, we would advertise MTU as 3950, and
we would reject fragmented IPv6 datagrams of 3958 bytes size on the
wire. We're exclusively dealing with network MTU here, though, so we
could get Ethernet frames up to 3964 octets in that case.
v2:
- moved skb_tunnel_check_pmtu() to ip_tunnel_core.c (David Ahern)
- split IPv4/IPv6 functions (David Ahern)
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Previous changes to the IP routing code have removed all the
tests for the DS_HOST route flag.
Remove the flags and all the code that sets it.
Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.
So disable the neigh confirm for vxlan and geneve pmtu update.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
Fixes: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new function skb_dst_update_pmtu_no_confirm() for callers who need
update pmtu but should not do neighbor confirm.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.
But for tunnel code, it will call pmtu before xmit, like:
- tnl_update_pmtu()
- skb_dst_update_pmtu()
- ip6_rt_update_pmtu()
- __ip6_rt_update_pmtu()
- dst_confirm_neigh()
If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.
So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.
On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.
To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When storing a pointer to a dst_metrics structure in dst_entry._metrics,
two flags are added in the least significant bits of the pointer value.
Hence this assumes all pointers to dst_metrics structures have at least
4-byte alignment.
However, on m68k, the minimum alignment of 32-bit values is 2 bytes, not
4 bytes. Hence in some kernel builds, dst_default_metrics may be only
2-byte aligned, leading to obscure boot warnings like:
WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x44/0x9a
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 7 Comm: ksoftirqd/0 Tainted: G W 5.5.0-rc2-atari-01448-g114a1a1038af891d-dirty #261
Stack from 10835e6c:
10835e6c 0038134f 00023fa6 00394b0f 0000001c 00000009 00321560 00023fea
00394b0f 0000001c 001a70f8 00000009 00000000 10835eb4 00000001 00000000
04208040 0000000a 00394b4a 10835ed4 00043aa8 001a70f8 00394b0f 0000001c
00000009 00394b4a 0026aba8 003215a4 00000003 00000000 0026d5a8 00000001
003215a4 003a4361 003238d6 000001f0 00000000 003215a4 10aa3b00 00025e84
003ddb00 10834000 002416a8 10aa3b00 00000000 00000080 000aa038 0004854a
Call Trace: [<00023fa6>] __warn+0xb2/0xb4
[<00023fea>] warn_slowpath_fmt+0x42/0x64
[<001a70f8>] refcount_warn_saturate+0x44/0x9a
[<00043aa8>] printk+0x0/0x18
[<001a70f8>] refcount_warn_saturate+0x44/0x9a
[<0026aba8>] refcount_sub_and_test.constprop.73+0x38/0x3e
[<0026d5a8>] ipv4_dst_destroy+0x5e/0x7e
[<00025e84>] __local_bh_enable_ip+0x0/0x8e
[<002416a8>] dst_destroy+0x40/0xae
Fix this by forcing 4-byte alignment of all dst_metrics structures.
Fixes: e5fd387ad5 ("ipv6: do not overwrite inetpeer metrics prematurely")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix DST_FEATURE_ECN_CA to use "U" cast to avoid shifting signed
32-bit value by 31 bits problem.
Signed-off-by: Vandana BN <bnvandana@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netfilter did not expect that skb_dst_force() can cause skb to lose its
dst entry.
I got a bug report with a skb->dst NULL dereference in netfilter
output path. The backtrace contains nf_reinject(), so the dst might have
been cleared when skb got queued to userspace.
Other users were fixed via
if (skb_dst(skb)) {
skb_dst_force(skb);
if (!skb_dst(skb))
goto handle_err;
}
But I think its preferable to make the 'dst might be cleared' part
of the function explicit.
In netfilter case, skb with a null dst is expected when queueing in
prerouting hook, so drop skb for the other hooks.
v2:
v1 of this patch returned true in case skb had no dst entry.
Eric said:
Say if we have two skb_dst_force() calls for some reason
on the same skb, only the first one will return false.
This now returns false even when skb had no dst, as per Erics
suggestion, so callers might need to check skb_dst() first before
skb_dst_force().
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
We shouldn't abuse exceptions: if the destination MTU is already higher
than what we're transmitting, no exception should be created.
Fixes: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to remove performance impact of having the extra u32 in every
single flowi, this change removes the flowi_xfrm struct, prefering to
take the if_id as a method parameter where needed.
In the inbound direction, if_id is only needed during the
__xfrm_check_policy() function, and the if_id can be determined at that
point based on the skb. As such, xfrmi_decode_session() is only called
with the skb in __xfrm_check_policy().
In the outbound direction, the only place where if_id is needed is the
xfrm_lookup() call in xfrmi_xmit2(). With this change, the if_id is
directly passed into the xfrm_lookup_with_ifid() call. All existing
callers can still call xfrm_lookup(), which uses a default if_id of 0.
This change does not change any behavior of XFRMIs except for improving
overall system performance via flowi size reduction.
This change has been tested against the Android Kernel Networking Tests:
https://android.googlesource.com/kernel/tests/+/master/net/test
Signed-off-by: Benedict Wong <benedictwong@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This fixes the following kernel-doc warning:
./include/net/dst.h:366: warning: Function parameter or member 'net' not described in 'skb_tunnel_rx'
Fixes: ea23192e8e ("tunnels: harmonize cleanup done on skb on rx path")
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
"BUG: unable to handle kernel NULL pointer dereference at (null)"
Let's add a helper to check if update_pmtu is available before calling it.
Fixes: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
CC: Roman Kapl <code@rkapl.cz>
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We have padding to try and align the refcount on a separate cache
line. But after several simplifications the padding has increased
substantially.
So now it's easy to change the layout to get rid of the padding
entirely.
We group the write-heavy __refcnt and __use with less often used
items such as the rcu_head and the error code.
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
