Convert the ->flowic_tos field of struct flowi_common from __u8 to
dscp_t, rename it ->flowic_dscp and propagate these changes to struct
flowi and struct flowi4.
We've had several bugs in the past where ECN bits could interfere with
IPv4 routing, because these bits were not properly cleared when setting
->flowi4_tos. These bugs should be fixed now and the dscp_t type has
been introduced to ensure that variables carrying DSCP values don't
accidentally have any ECN bits set. Several variables and structure
fields have been converted to dscp_t already, but the main IPv4 routing
structure, struct flowi4, is still using a __u8. To avoid any future
regression, this patch converts it to dscp_t.
There are many users to convert at once. Fortunately, around half of
->flowi4_tos users already have a dscp_t value at hand, which they
currently convert to __u8 using inet_dscp_to_dsfield(). For all of
these users, we just need to drop that conversion.
But, although we try to do the __u8 <-> dscp_t conversions at the
boundaries of the network or of user space, some places still store
TOS/DSCP variables as __u8 in core networking code. Those can hardly be
converted either because the data structure is part of UAPI or because
the same variable or field is also used for handling ECN in other parts
of the code. In all of these cases where we don't have a dscp_t
variable at hand, we need to use inet_dsfield_to_dscp() when
interacting with ->flowi4_dscp.
Changes since v1:
* Fix space alignment in __bpf_redirect_neigh_v4() (Ido).
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/29acecb45e911d17446b9a3dbdb1ab7b821ea371.1756128932.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IPv4 FIB rules cannot match on flow label so reject requests that try to
add such rules. Do that in the IPv4 configure callback as the netlink
policy resides in the core and used by both IPv4 and IPv6.
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Implement support for the new DSCP selector that allows IPv4 FIB rules
to match on the entire DSCP field, unlike the existing TOS selector that
only matches on the three lower DSCP bits.
Differentiate between both selectors by adding a new bit in the IPv4 FIB
rule structure (in an existing one byte hole) that is only set when the
'FRA_DSCP' attribute is specified by user space. Reject rules that use
both selectors.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240911093748.3662015-3-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The TOS field in the IPv4 flow information structure ('flowi4_tos') is
matched by the kernel against the TOS selector in IPv4 rules and routes.
The field is initialized differently by different call sites. Some treat
it as DSCP (RFC 2474) and initialize all six DSCP bits, some treat it as
RFC 1349 TOS and initialize it using RT_TOS() and some treat it as RFC
791 TOS and initialize it using IPTOS_RT_MASK.
What is common to all these call sites is that they all initialize the
lower three DSCP bits, which fits the TOS definition in the initial IPv4
specification (RFC 791).
Therefore, the kernel only allows configuring IPv4 FIB rules that match
on the lower three DSCP bits which are always guaranteed to be
initialized by all call sites:
# ip -4 rule add tos 0x1c table 100
# ip -4 rule add tos 0x3c table 100
Error: Invalid tos.
While this works, it is unlikely to be very useful. RFC 791 that
initially defined the TOS and IP precedence fields was updated by RFC
2474 over twenty five years ago where these fields were replaced by a
single six bits DSCP field.
Extending FIB rules to match on DSCP can be done by adding a new DSCP
selector while maintaining the existing semantics of the TOS selector
for applications that rely on that.
A prerequisite for allowing FIB rules to match on DSCP is to adjust all
the call sites to initialize the high order DSCP bits and remove their
masking along the path to the core where the field is matched on.
However, making this change alone will result in a behavior change. For
example, a forwarded IPv4 packet with a DS field of 0xfc will no longer
match a FIB rule that was configured with 'tos 0x1c'.
This behavior change can be avoided by masking the upper three DSCP bits
in 'flowi4_tos' before comparing it against the TOS selectors in FIB
rules and routes.
Implement the above by adding a new function that checks whether a given
DSCP value matches the one specified in the IPv4 flow information
structure and invoke it from the three places that currently match on
'flowi4_tos'.
Use RT_TOS() for the masking of 'flowi4_tos' instead of IPTOS_RT_MASK
since the latter is not uAPI and we should be able to remove it at some
point.
Include <linux/ip.h> in <linux/in_route.h> since the former defines
IPTOS_TOS_MASK which is used in the definition of RT_TOS() in
<linux/in_route.h>.
No regressions in FIB tests:
# ./fib_tests.sh
[...]
Tests passed: 218
Tests failed: 0
And FIB rule tests:
# ./fib_rule_tests.sh
[...]
Tests passed: 116
Tests failed: 0
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Commit 563f8e97e0 ("ipv4: Stop taking ECN bits into account in
fib4-rules") replaced the validation test on frh->tos. While the new
test is stricter for ECN bits, it doesn't detect the use of high order
DSCP bits. This would be fine if IPv4 could properly handle them. But
currently, most IPv4 lookups are done with the three high DSCP bits
masked. Therefore, using these bits doesn't lead to the expected
result.
Let's reject such configurations again, so that nobody starts to
use and make any assumption about how the stack handles the three high
order DSCP bits in fib4 rules.
Fixes: 563f8e97e0 ("ipv4: Stop taking ECN bits into account in fib4-rules")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the new dscp_t type to replace the tos field of struct fib4_rule,
so that fib4-rules consistently ignore ECN bits.
Before this patch, fib4-rules did accept rules with the high order ECN
bit set (but not the low order one). Also, it relied on its callers
masking the ECN bits of ->flowi4_tos to prevent those from influencing
the result. This was brittle and a few call paths still do the lookup
without masking the ECN bits first.
After this patch fib4-rules only compare the DSCP bits. ECN can't
influence the result anymore, even if the caller didn't mask these
bits. Also, fib4-rules now must have both ECN bits cleared or they will
be rejected.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The attributes are identical in all implementations so move the ipv4 one
into the core and remove the per-family nla policies.
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Before commit faa041a40b ("ipv4: Create cleanup helper for fib_nh")
changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.
After the change, this is no longer the case, as free_fib_info_rcu()
runs after rcu grace period, without rtnl being held.
Fixes: faa041a40b ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The kernel leaks memory when a `fib` rule is present in IPv6 nftables
firewall rules and a suppress_prefix rule is present in the IPv6 routing
rules (used by certain tools such as wg-quick). In such scenarios, every
incoming packet will leak an allocation in `ip6_dst_cache` slab cache.
After some hours of `bpftrace`-ing and source code reading, I tracked
down the issue to ca7a03c417 ("ipv6: do not free rt if
FIB_LOOKUP_NOREF is set on suppress rule").
The problem with that change is that the generic `args->flags` always have
`FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag
`RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not
decreasing the refcount when needed.
How to reproduce:
- Add the following nftables rule to a prerouting chain:
meta nfproto ipv6 fib saddr . mark . iif oif missing drop
This can be done with:
sudo nft create table inet test
sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }'
sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop
- Run:
sudo ip -6 rule add table main suppress_prefixlength 0
- Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase
with every incoming ipv6 packet.
This patch exposes the protocol-specific flags to the protocol
specific `suppress` function, and check the protocol-specific `flags`
argument for RT6_LOOKUP_F_DST_NOREF instead of the generic
FIB_LOOKUP_NOREF when decreasing the refcount, like this.
[1]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L71
[2]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L99
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215105
Fixes: ca7a03c417 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule")
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This avoids another inderect call per RX packet which save us around
20-40 ns.
Changelog:
v1 -> v2:
- Move declaraions to fib_rules.h to remove warnings
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since errors are propagated all the way up to the caller, propagate
possible extack of the caller all the way down to the notifier block
callback.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some ISDN files that got removed in net-next had some changes
done in mainline, take the removals.
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert more IPv4 code to use fib_nh_common over fib_nh to enable routes
to use a fib6_nh based nexthop. In the end, only code not using a
nexthop object in a fib_info should directly access fib_nh in a fib_info
without checking the famiy and going through fib_nh_common. Those
functions will be marked when it is not directly evident.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use helpers to access fib_nh and fib_nhs fields of a fib_info. Drop the
fib_dev macro which is an alias for the first nexthop. Replacements:
fi->fib_dev --> fib_info_nh(fi, 0)->fib_nh_dev
fi->fib_nh --> fib_info_nh(fi, 0)
fi->fib_nh[i] --> fib_info_nh(fi, i)
fi->fib_nhs --> fib_info_num_path(fi)
where fib_info_nh(fi, i) returns fi->fib_nh[nhsel] and fib_info_num_path
returns fi->fib_nhs.
Move the existing fib_info_nhc to nexthop.h and define the new ones
there. A later patch adds a check if a fib_info uses a nexthop object,
and defining the helpers in nexthop.h avoid circular header
dependencies.
After this all remaining open coded references to fi->fib_nhs and
fi->fib_nh are in:
- fib_create_info and helpers used to lookup an existing fib_info
entry, and
- the netdev event functions fib_sync_down_dev and fib_sync_up.
The latter two will not be reused for nexthops, and the fib_create_info
will be updated to handle a nexthop in a fib_info.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
gcc warn this:
net/ipv4/fib_rules.c:203 fib_empty_table() warn:
always true condition '(id <= 4294967295) => (0-u32max <= u32max)'
'id' is u32, which always not greater than RT_TABLE_MAX
(0xFFFFFFFF), So add a check to break while wrap around.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Dissect flow in fwd path if fib rules require it. Controlled by
a flag to avoid penatly for the common case. Flag is set when fib
rules with sport, dport and proto match that require flow dissect
are installed. Also passes the dissected hash keys to the multipath
hash function when applicable to avoid dissecting the flow again.
icmp packets will continue to use inner header for hash
calculations (Thanks to Nikolay Aleksandrov for some review here).
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
