This reverts commit eb55dc09.

The patch that introduces this bug is reverted right after this one.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

__mkroute_input() uses fib_validate_source() to trigger an icmp redirect.
My understanding is that fib_validate_source() is used to know if the src
address and the gateway address are on the same link. For that,
fib_validate_source() returns 1 (same link) or 0 (not the same network).
__mkroute_input() is the only user of these positive values, all other
callers only look if the returned value is negative.

Since the below patch, fib_validate_source() didn't return anymore 1 when
both addresses are on the same network, because the route lookup returns
RT_SCOPE_LINK instead of RT_SCOPE_HOST. But this is, in fact, right.
Let's adapat the test to return 1 again when both addresses are on the same
link.

CC: stable@vger.kernel.org
Fixes: 747c1430 ("ip: fix dflt addr selection for connected nexthop")
Reported-by: Nkernel test robot <yujie.liu@intel.com>
Reported-by: NHeng Qi <hengqi@linux.alibaba.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220829100121.3821-1-nicolas.dichtel@6wind.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

remove unnecessary void* type castings.
Signed-off-by: NYu Zhe <yuzhe@nfschina.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The fundamental premise of VRF and l3mdev core code is binding a socket
to a device (l3mdev or netdev with an L3 domain) to indicate L3 scope.
Legacy code resets flowi_oif to the l3mdev losing any original port
device binding. Ben (among others) has demonstrated use cases where the
original port device binding is important and needs to be retained.
This patch handles that by adding a new entry to the common flow struct
that can indicate the l3mdev index for later rule and table matching
avoiding the need to reset flowi_oif.

In addition to allowing more use cases that require port device binds,
this patch brings a few datapath simplications:

1. l3mdev_fib_rule_match is only called when walking fib rules and
   always after l3mdev_update_flow. That allows an optimization to bail
   early for non-VRF type uses cases when flowi_l3mdev is not set. Also,
   only that index needs to be checked for the FIB table id.

2. l3mdev_update_flow can be called with flowi_oif set to a l3mdev
   (e.g., VRF) device. By resetting flowi_oif only for this case the
   FLOWI_FLAG_SKIP_NH_OIF flag is not longer needed and can be removed,
   removing several checks in the datapath. The flowi_iif path can be
   simplified to only be called if the it is not loopback (loopback can
   not be assigned to an L3 domain) and the l3mdev index is not already
   set.

3. Avoid another device lookup in the output path when the fib lookup
   returns a reject failure.

Note: 2 functional tests for local traffic with reject fib rules are
updated to reflect the new direct failure at FIB lookup time for ping
rather than the failure on packet path. The current code fails like this:

    HINT: Fails since address on vrf device is out of device scope
    COMMAND: ip netns exec ns-A ping -c1 -w1 -I eth1 172.16.3.1
    ping: Warning: source address might be selected on device other than: eth1
    PING 172.16.3.1 (172.16.3.1) from 172.16.3.1 eth1: 56(84) bytes of data.

    --- 172.16.3.1 ping statistics ---
    1 packets transmitted, 0 received, 100% packet loss, time 0ms

where the test now directly fails:

    HINT: Fails since address on vrf device is out of device scope
    COMMAND: ip netns exec ns-A ping -c1 -w1 -I eth1 172.16.3.1
    ping: connect: No route to host
Signed-off-by: NDavid Ahern <dsahern@kernel.org>
Tested-by: NBen Greear <greearb@candelatech.com>
Link: https://lore.kernel.org/r/20220314204551.16369-1-dsahern@kernel.orgSigned-off-by: NJakub Kicinski <kuba@kernel.org>

In case user space sends a packet destined to a broadcast address when a
matching broadcast route is not configured, the kernel will create a
unicast neighbour entry that will never be resolved [1].

When the broadcast route is configured, the unicast neighbour entry will
not be invalidated and continue to linger, resulting in packets being
dropped.

Solve this by invalidating unresolved neighbour entries for broadcast
addresses after routes for these addresses are internally configured by
the kernel. This allows the kernel to create a broadcast neighbour entry
following the next route lookup.

Another possible solution that is more generic but also more complex is
to have the ARP code register a listener to the FIB notification chain
and invalidate matching neighbour entries upon the addition of broadcast
routes.

It is also possible to wave off the issue as a user space problem, but
it seems a bit excessive to expect user space to be that intimately
familiar with the inner workings of the FIB/neighbour kernel code.

[1] https://lore.kernel.org/netdev/55a04a8f-56f3-f73c-2aea-2195923f09d1@huawei.com/Reported-by: NWang Hai <wanghai38@huawei.com>
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Tested-by: NWang Hai <wanghai38@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When multiple containers are running in the environment and multiple
macvlan network port are configured in each container, a lot of martian
source prints will appear after martian_log is enabled. they are almost
the same, and printed by net_warn_ratelimited. Each arp message will
trigger this print on each network port.

Such as:
IPv4: martian source 173.254.95.16 from 173.254.100.109,
on dev eth0
ll header: 00000000: ff ff ff ff ff ff 40 00 ad fe 64 6d
08 06        ......@...dm..
IPv4: martian source 173.254.95.16 from 173.254.100.109,
on dev eth1
ll header: 00000000: ff ff ff ff ff ff 40 00 ad fe 64 6d
08 06        ......@...dm..

There is no description of this kind of source in the RFC1812.
Signed-off-by: NZhang Yunkai <zhang.yunkai@zte.com.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

cleanup_net() is competing with other rtnl users.

Instead of acquiring rtnl at each fib_net_exit() invocation,
add fib_net_exit_batch() so that rtnl is acquired once.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Use the new dscp_t type to replace the fc_tos field of fib_config, to
ensure IPv4 routes aren't influenced by ECN bits when configured with
non-zero rtm_tos.

Before this patch, IPv4 routes specifying an rtm_tos with some of the
ECN bits set were accepted. However they wouldn't work (never match) as
IPv4 normally clears the ECN bits with IPTOS_RT_MASK before doing a FIB
lookup (although a few buggy code paths don't).

After this patch, IPv4 routes specifying an rtm_tos with any ECN bit
set is rejected.

Note: IPv6 routes ignore rtm_tos altogether, any rtm_tos is accepted,
but treated as if it were 0.
Signed-off-by: NGuillaume Nault <gnault@redhat.com>
Acked-by: NDavid Ahern <dsahern@kernel.org>
Reviewed-by: NToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Before commit faa041a4 ("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: faa041a4 ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It has 'if (err >0 )' statement in nlmsg_unicast(), so use nlmsg_unicast()
instead of netlink_unicast(), this looks more concise.

v2: remove the change in netfilter.
Signed-off-by: NYajun Deng <yajun.deng@linux.dev>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When doing source address validation, the flowi4 struct used for
fib_lookup should be in the reverse direction to the given skb.
fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
should thus be swapped.

Fixes: 5a847a6e ("net/ipv4: Initialize proto and ports in flow struct")
Signed-off-by: NMiao Wang <shankerwangmiao@gmail.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A subsequent patch will add a new multipath hash policy where the packet
fields used for multipath hash calculation are determined by user space.
This patch adds a sysctl that allows user space to set these fields.

The packet fields are represented using a bitmask and are common between
IPv4 and IPv6 to allow user space to use the same numbering across both
protocols. For example, to hash based on standard 5-tuple:

 # sysctl -w net.ipv4.fib_multipath_hash_fields=0x0037
 net.ipv4.fib_multipath_hash_fields = 0x0037

The kernel rejects unknown fields, for example:

 # sysctl -w net.ipv4.fib_multipath_hash_fields=0x1000
 sysctl: setting key "net.ipv4.fib_multipath_hash_fields": Invalid argument

More fields can be added in the future, if needed.
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Treat only the highest, not the lowest, IPv4 address within a local
subnet as a broadcast address.
Signed-off-by: NSeth David Schoen <schoen@loyalty.org>
Suggested-by: NJohn Gilmore <gnu@toad.com>
Acked-by: NDave Taht <dave.taht@gmail.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RT_TOS() only clears one of the ECN bits. Therefore, when
fib_compute_spec_dst() resorts to a fib lookup, it can return
different results depending on the value of the second ECN bit.

For example, ECT(0) and ECT(1) packets could be treated differently.

  $ ip netns add ns0
  $ ip netns add ns1
  $ ip link add name veth01 netns ns0 type veth peer name veth10 netns ns1
  $ ip -netns ns0 link set dev lo up
  $ ip -netns ns1 link set dev lo up
  $ ip -netns ns0 link set dev veth01 up
  $ ip -netns ns1 link set dev veth10 up

  $ ip -netns ns0 address add 192.0.2.10/24 dev veth01
  $ ip -netns ns1 address add 192.0.2.11/24 dev veth10

  $ ip -netns ns1 address add 192.0.2.21/32 dev lo
  $ ip -netns ns1 route add 192.0.2.10/32 tos 4 dev veth10 src 192.0.2.21
  $ ip netns exec ns1 sysctl -wq net.ipv4.icmp_echo_ignore_broadcasts=0

With TOS 4 and ECT(1), ns1 replies using source address 192.0.2.21
(ping uses -Q to set all TOS and ECN bits):

  $ ip netns exec ns0 ping -c 1 -b -Q 5 192.0.2.255
  [...]
  64 bytes from 192.0.2.21: icmp_seq=1 ttl=64 time=0.544 ms

But with TOS 4 and ECT(0), ns1 replies using source address 192.0.2.11
because the "tos 4" route isn't matched:

  $ ip netns exec ns0 ping -c 1 -b -Q 6 192.0.2.255
  [...]
  64 bytes from 192.0.2.11: icmp_seq=1 ttl=64 time=0.597 ms

After this patch the ECN bits don't affect the result anymore:

  $ ip netns exec ns0 ping -c 1 -b -Q 6 192.0.2.255
  [...]
  64 bytes from 192.0.2.21: icmp_seq=1 ttl=64 time=0.591 ms

Fixes: 35ebf65e ("ipv4: Create and use fib_compute_spec_dst() helper.")
Signed-off-by: NGuillaume Nault <gnault@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: d1566268 ("ipv4: Allow ipv6 gateway with ipv4 routes")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NZhang Changzhong <zhangchangzhong@huawei.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/1607071695-33740-1-git-send-email-zhangchangzhong@huawei.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Checking for ifdef CONFIG_x fails if CONFIG_x=m.

Use IS_ENABLED instead, which is true for both built-ins and modules.

Otherwise, a
> ip -4 route add 1.2.3.4/32 via inet6 fe80::2 dev eth1
fails with the message "Error: IPv6 support not enabled in kernel." if
CONFIG_IPV6 is `m`.

In the spirit of b8127113.

Fixes: d1566268 ("ipv4: Allow ipv6 gateway with ipv4 routes")
Cc: Kim Phillips <kim.phillips@arm.com>
Signed-off-by: NFlorian Klink <flokli@flokli.de>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20201115224509.2020651-1-flokli@flokli.deSigned-off-by: NJakub Kicinski <kuba@kernel.org>

flowi4_multipath_hash was added by the commit referenced below for
tunnels. Unfortunately, the patch did not initialize the new field
for several fast path lookups that do not initialize the entire flow
struct to 0. Fix those locations. Currently, flowi4_multipath_hash
is random garbage and affects the hash value computed by
fib_multipath_hash for multipath selection.

Fixes: 24ba1440 ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Cc: wenxu <wenxu@ucloud.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Similar to the last path, need to fix fib_info_nh_uses_dev for
external nexthops to avoid referencing multiple nh_grp structs.
Move the device check in fib_info_nh_uses_dev to a helper and
create a nexthop version that is called if the fib_info uses an
external nexthop.

Fixes: 430a0491 ("nexthop: Add support for nexthop groups")
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case we can't find a ->dumpit callback for the requested
(family,type) pair, we fall back to (PF_UNSPEC,type). In effect, we're
in the same situation as if userspace had requested a PF_UNSPEC
dump. For RTM_GETROUTE, that handler is rtnl_dump_all, which calls all
the registered RTM_GETROUTE handlers.

The requested table id may or may not exist for all of those
families. commit ae677bbb ("net: Don't return invalid table id
error when dumping all families") fixed the problem when userspace
explicitly requests a PF_UNSPEC dump, but missed the fallback case.

For example, when we pass ipv6.disable=1 to a kernel with
CONFIG_IP_MROUTE=y and CONFIG_IP_MROUTE_MULTIPLE_TABLES=y,
the (PF_INET6, RTM_GETROUTE) handler isn't registered, so we end up in
rtnl_dump_all, and listing IPv6 routes will unexpectedly print:

  # ip -6 r
  Error: ipv4: MR table does not exist.
  Dump terminated

commit ae677bbb introduced the dump_all_families variable, which
gets set when userspace requests a PF_UNSPEC dump. However, we can't
simply set the family to PF_UNSPEC in rtnetlink_rcv_msg in the
fallback case to get dump_all_families == true, because some messages
types (for example RTM_GETRULE and RTM_GETNEIGH) only register the
PF_UNSPEC handler and use the family to filter in the kernel what is
dumped to userspace. We would then export more entries, that userspace
would have to filter. iproute does that, but other programs may not.

Instead, this patch removes dump_all_families and updates the
RTM_GETROUTE handlers to check if the family that is being dumped is
their own. When it's not, which covers both the intentional PF_UNSPEC
dumps (as dump_all_families did) and the fallback case, ignore the
missing table id error.

Fixes: cb167893 ("net: Plumb support for filtering ipv4 and ipv6 multicast route dumps")
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a place,

inet_dump_fib()
  fib_table_dump
    fn_trie_dump_leaf()
      hlist_for_each_entry_rcu()

without rcu_read_lock() will trigger a warning,

 WARNING: suspicious RCU usage
 -----------------------------
 net/ipv4/fib_trie.c:2216 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 1 lock held by ip/1923:
  #0: ffffffff8ce76e40 (rtnl_mutex){+.+.}, at: netlink_dump+0xd6/0x840

 Call Trace:
  dump_stack+0xa1/0xea
  lockdep_rcu_suspicious+0x103/0x10d
  fn_trie_dump_leaf+0x581/0x590
  fib_table_dump+0x15f/0x220
  inet_dump_fib+0x4ad/0x5d0
  netlink_dump+0x350/0x840
  __netlink_dump_start+0x315/0x3e0
  rtnetlink_rcv_msg+0x4d1/0x720
  netlink_rcv_skb+0xf0/0x220
  rtnetlink_rcv+0x15/0x20
  netlink_unicast+0x306/0x460
  netlink_sendmsg+0x44b/0x770
  __sys_sendto+0x259/0x270
  __x64_sys_sendto+0x80/0xa0
  do_syscall_64+0x69/0xf4
  entry_SYSCALL_64_after_hwframe+0x49/0xb3

Fixes: 18a8021a ("net/ipv4: Plumb support for filtering route dumps")
Signed-off-by: NQian Cai <cai@lca.pw>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So that we can use it in the next patch.
Additionally constify the helper argument.
Suggested-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit af4d768a ("net/ipv4: Add support for specifying metric
of connected routes"), when updating an IP address with a different metric,
the associated connected route is updated, too.

Still, the mentioned commit doesn't handle properly some corner cases:

$ ip addr add dev eth0 192.168.1.0/24
$ ip addr add dev eth0 192.168.2.1/32 peer 192.168.2.2
$ ip addr add dev eth0 192.168.3.1/24
$ ip addr change dev eth0 192.168.1.0/24 metric 10
$ ip addr change dev eth0 192.168.2.1/32 peer 192.168.2.2 metric 10
$ ip addr change dev eth0 192.168.3.1/24 metric 10
$ ip -4 route
192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.0
192.168.2.2 dev eth0 proto kernel scope link src 192.168.2.1
192.168.3.0/24 dev eth0 proto kernel scope link src 192.168.2.1 metric 10

Only the last route is correctly updated.

The problem is the current test in fib_modify_prefix_metric():

	if (!(dev->flags & IFF_UP) ||
	    ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
	    ipv4_is_zeronet(prefix) ||
	    prefix == ifa->ifa_local || ifa->ifa_prefixlen == 32)

Which should be the logical 'not' of the pre-existing test in
fib_add_ifaddr():

	if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
	    (prefix != addr || ifa->ifa_prefixlen < 32))

To properly negate the original expression, we need to change the last
logical 'or' to a logical 'and'.

Fixes: af4d768a ("net/ipv4: Add support for specifying metric of connected routes")
Reported-and-suggested-by: NBeniamino Galvani <bgalvani@redhat.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This commit applies the consolidated list_for_each_entry_rcu() support
for lockdep conditions.
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.ibm.com>

In a rare case where we redirect local packets from veth to lo,
these packets fail to pass the source validation when rp_filter
is turned on, as the tracing shows:

  <...>-311708 [040] ..s1 7951180.957825: fib_table_lookup: table 254 oif 0 iif 1 src 10.53.180.130 dst 10.53.180.130 tos 0 scope 0 flags 0
  <...>-311708 [040] ..s1 7951180.957826: fib_table_lookup_nh: nexthop dev eth0 oif 4 src 10.53.180.130

So, the fib table lookup returns eth0 as the nexthop even though
the packets are local and should be routed to loopback nonetheless,
but they can't pass the dev match check in fib_info_nh_uses_dev()
without this patch.

It should be safe to relax this check for this special case, as
normally packets coming out of loopback device still have skb_dst
so they won't even hit this slow path.

Cc: Julian Anastasov <ja@ssi.bg>
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This functionally reverts the check introduced by commit
e8ba330a ("rtnetlink: Update fib dumps for strict data checking")
as modified by commit e4e92fb1 ("net/ipv4: Bail early if user only
wants prefix entries").

As we are preparing to fix listing of IPv4 cached routes, we need to
give userspace a way to request them.
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The following patches add back the ability to dump IPv4 and IPv6 exception
routes, and we need to allow selection of regular routes or exceptions.

Use RTM_F_CLONED as filter to decide whether to dump routes or exceptions:
iproute2 passes it in dump requests (except for IPv6 cache flush requests,
this will be fixed in iproute2) and this used to work as long as
exceptions were stored directly in the FIB, for both IPv4 and IPv6.

Caveat: if strict checking is not requested (that is, if the dump request
doesn't go through ip_valid_fib_dump_req()), we can't filter on protocol,
tables or route types.

In this case, filtering on RTM_F_CLONED would be inconsistent: we would
fix 'ip route list cache' by returning exception routes and at the same
time introduce another bug in case another selector is present, e.g. on
'ip route list cache table main' we would return all exception routes,
without filtering on tables.

Keep this consistent by applying no filters at all, and dumping both
routes and exceptions, if strict checking is not requested. iproute2
currently filters results anyway, and no unwanted results will be
presented to the user. The kernel will just dump more data than needed.

v7: No changes

v6: Rebase onto net-next, no changes

v5: New patch: add dump_routes and dump_exceptions flags in filter and
    simply clear the unwanted one if strict checking is enabled, don't
    ignore NLM_F_MATCH and don't set filter_set if NLM_F_MATCH is set.
    Skip filtering altogether if no strict checking is requested:
    selecting routes or exceptions only would be inconsistent with the
    fact we can't filter on tables.
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for RTA_NH_ID attribute to allow a user to specify a
nexthop id to use with a route. fc_nh_id is added to fib_config to
hold the value passed in the RTA_NH_ID attribute. If a nexthop id
is given, the gateway, device, encap and multipath attributes can
not be set.

Update fib_nh_match to check ids on a route delete.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid 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: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid 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: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use in_dev_for_each_ifa_rcu/rtnl instead.
This prevents sparse warnings once proper __rcu annotations are added.
Signed-off-by: NFlorian Westphal <fw@strlen.de>

t di# Last commands done (6 commands done):
Signed-off-by: NDavid 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: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

New userspace on an older kernel can send unknown and unsupported
attributes resulting in an incompelete config which is almost
always wrong for routing (few exceptions are passthrough settings
like the protocol that installed the route).

Set strict_start_type in the policies for IPv4 and IPv6 routes and
rules to detect new, unsupported attributes and fail the route add.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As nexthops are deleted, fib entries referencing it are marked dead.
Export fib_flush so those entries can be removed in a timely manner.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Govindarajulu reported a regression with Network Manager which sends an
RTA_GATEWAY attribute with the address set to 0. Fixup the handling of
RTA_GATEWAY to only set fc_gw_family if the gateway address is actually
set.

Fixes: f35b794b ("ipv4: Prepare fib_config for IPv6 gateway")
Reported-by: NGovindarajulu Varadarajan <govind.varadar@gmail.com>
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for RTA_VIA and allow an IPv6 nexthop for v4 routes:
   $ ip ro add 172.16.1.0/24 via inet6 2001:db8::1 dev eth0
   $ ip ro ls
   ...
   172.16.1.0/24 via inet6 2001:db8::1 dev eth0

For convenience and simplicity, userspace can use RTA_VIA to specify
AF_INET or AF_INET6 gateway.

The common fib_nexthop_info dump function compares the gateway address
family to the nh_common family to know if the gateway should be encoded
as RTA_VIA or RTA_GATEWAY.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Similar to rtable, fib_config needs to allow the gateway to be either an
IPv4 or an IPv6 address. To that end, rename fc_gw to fc_gw4 to mean an
IPv4 address and add fc_gw_family. Checks on 'is a gateway set' are changed
to see if fc_gw_family is set. In the process prepare the code for a
fc_gw_family == AF_INET6.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Reviewed-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Most of the ipv4 code only needs data from fib_nh_common. Add
fib_nh_common selection to fib_result and update users to use it.

Right now, fib_nh_common in fib_result will point to a fib_nh struct
that is embedded within a fib_info:

        fib_info  --> fib_nh
                      fib_nh
                      ...
                      fib_nh
                        ^
    fib_result->nhc ----+

Later, nhc can point to a fib_nh within a nexthop struct:

        fib_info --> nexthop --> fib_nh
                                   ^
    fib_result->nhc ---------------+

or for a nexthop group:

        fib_info --> nexthop --> nexthop --> fib_nh
                                 nexthop --> fib_nh
                                 ...
                                 nexthop --> fib_nh
                                               ^
    fib_result->nhc ---------------------------+

In all cases nhsel within fib_result will point to which leg in the
multipath route is used.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename fib_nh entries that will be moved to a fib_nh_common struct.
Specifically, the device, oif, gateway, flags, scope, lwtstate,
nh_weight and nh_upper_bound are common with all nexthop definitions.
In the process shorten fib_nh_lwtstate to fib_nh_lws to avoid really
long lines.

Rename only; no functional change intended.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv4 currently does not support nexthops outside of the AF_INET family.
Specifically, it does not handle RTA_VIA attribute. If it is passed
in a route add request, the actual route added only uses the device
which is clearly not what the user intended:

  $ ip ro add 172.16.1.0/24 via inet6 2001:db8:1::1 dev eth0
  $ ip ro ls
  ...
  172.16.1.0/24 dev eth0

Catch this and fail the route add:
  $ ip ro add 172.16.1.0/24 via inet6 2001:db8:1::1 dev eth0
  Error: IPv4 does not support RTA_VIA attribute.

Fixes: 03c05665 ("mpls: Netlink commands to add, remove, and dump routes")
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>