The RTN_ type for IPv6 FIB entries is currently embedded in rt6i_flags
and dst.error. Since dst is going to be removed, it can no longer be
relied on for FIB dumps so save the route type as fib6_type.
fc_type is set in current users based on the algorithm in rt6_fill_node:
- rt6i_flags contains RTF_LOCAL: fc_type = RTN_LOCAL
- rt6i_flags contains RTF_ANYCAST: fc_type = RTN_ANYCAST
- else fc_type = RTN_UNICAST
Similarly, fib6_type is set in the rt6_info templates based on the
RTF_REJECT section of rt6_fill_node converting dst.error to RTN type.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass network namespace reference into route add, delete and get
functions.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Send a netlink notification when userspace adds a manually configured
address if DAD is enabled and optimistic flag isn't set.
Moreover send RTM_DELADDR notifications for tentative addresses.
Some userspace applications (e.g. NetworkManager) are interested in
addr netlink events albeit the address is still in tentative state,
however events are not sent if DAD process is not completed.
If the address is added and immediately removed userspace listeners
are not notified. This behaviour can be easily reproduced by using
veth interfaces:
$ ip -b - <<EOF
> link add dev vm1 type veth peer name vm2
> link set dev vm1 up
> link set dev vm2 up
> addr add 2001:db8:a🅱️1:2:3:4/64 dev vm1
> addr del 2001:db8:a🅱️1:2:3:4/64 dev vm1
EOF
This patch reverts the behaviour introduced by the commit f784ad3d79
("ipv6: do not send RTM_DELADDR for tentative addresses")
Suggested-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove unnecessary check on update_lft variable in
addrconf_prefix_rcv_add_addr routine since it is always set to 0.
Moreover remove update_lft re-initialization to 0
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Synchronous pernet_operations are not allowed anymore.
All are asynchronous. So, drop the structure member.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove local ADBG macro and use netdev_dbg/pr_debug
Miscellanea:
o Remove unnecessary debug message after allocation failure as there
already is a dump_stack() on the failure paths
o Leave the allocation failure message on snmp6_alloc_dev as there
is one code path that does not do a dump_stack()
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Prefer the direct use of octal for permissions.
Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.
Miscellanea:
o Whitespace neatening around these conversions.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Lookup the L3 master device for the passed in device. Only consider
addresses on netdev's with the same master device. If the device is
not enslaved or is NULL, then the l3mdev is NULL which means only
devices not enslaved (ie, in the default domain) are considered.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6_chk_addr_and_flags determines if an address is a local address and
optionally if it is an address on a specific device. For example, it is
called by ip6_route_info_create to determine if a given gateway address
is a local address. The address check currently does not consider L3
domains and as a result does not allow a route to be added in one VRF
if the nexthop points to an address in a second VRF. e.g.,
$ ip route add 2001:db8:1::/64 vrf r2 via 2001:db8:102::23
Error: Invalid gateway address.
where 2001:db8:102::23 is an address on an interface in vrf r1.
ipv6_chk_addr_and_flags needs to allow callers to always pass in a device
with a separate argument to not limit the address to the specific device.
The device is used used to determine the L3 domain of interest.
To that end add an argument to skip the device check and update callers
to always pass a device where possible and use the new argument to mean
any address in the domain.
Update a handful of users of ipv6_chk_addr with a NULL dev argument. This
patch handles the change to these callers without adding the domain check.
ip6_validate_gw needs to handle 2 cases - one where the device is given
as part of the nexthop spec and the other where the device is resolved.
There is at least 1 VRF case where deferring the check to only after
the route lookup has resolved the device fails with an unintuitive error
"RTNETLINK answers: No route to host" as opposed to the preferred
"Error: Gateway can not be a local address." The 'no route to host'
error is because of the fallback to a full lookup. The check is done
twice to avoid this error.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
According to RFC 4429 (section 3.1), adding new IPv6 addresses as
optimistic addresses is acceptable, as long as the implementation
follows some rules:
* Optimistic DAD SHOULD only be used when the implementation is aware
that the address is based on a most likely unique interface
identifier (such as in [RFC2464]), generated randomly [RFC3041],
or by a well-distributed hash function [RFC3972] or assigned by
Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC3315].
Optimistic DAD SHOULD NOT be used for manually entered
addresses.
Thus, it seems reasonable to allow userspace to set the optimistic flag
when adding new addresses.
We must not let userspace set NODAD + OPTIMISTIC, since if the kernel is
not performing DAD we would never clear the optimistic flag. We must
also ignore userspace's request to add OPTIMISTIC flag to addresses that
have already completed DAD (addresses that don't have the TENTATIVE
flag, or that have the DADFAILED flag).
Then we also need to clear the OPTIMISTIC flag on permanent addresses
when DAD fails. Otherwise, IFA_F_OPTIMISTIC addresses added by userspace
can still be used after DAD has failed, because in
ipv6_chk_addr_and_flags(), IFA_F_OPTIMISTIC overrides IFA_F_TENTATIVE.
Setting IFA_F_OPTIMISTIC from userspace is conditional on
CONFIG_IPV6_OPTIMISTIC_DAD and the optimistic_dad sysctl.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These pernet_operations create and destroy /proc entries
and safely may be converted and safely may be mark as async.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These pernet_operations (un)register sysctl, which
are not touched by anybody else.
So, it's safe to make them async.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unsolicited IPv6 neighbor advertisements should be sent after DAD
completes. Update ndisc_send_unsol_na to skip tentative, non-optimistic
addresses and have those sent by addrconf_dad_completed after DAD.
Fixes: 4a6e3c5def ("net: ipv6: send unsolicited NA on admin up")
Reported-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
/proc has been ignoring struct file_operations::owner field for 10 years.
Specifically, it started with commit 786d7e1612
("Fix rmmod/read/write races in /proc entries"). Notice the chunk where
inode->i_fop is initialized with proxy struct file_operations for
regular files:
- if (de->proc_fops)
- inode->i_fop = de->proc_fops;
+ if (de->proc_fops) {
+ if (S_ISREG(inode->i_mode))
+ inode->i_fop = &proc_reg_file_ops;
+ else
+ inode->i_fop = de->proc_fops;
+ }
VFS stopped pinning module at this point.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to IPv4, when the carrier of a netdev changes we should toggle
the 'linkdown' flag on all the nexthops using it as their nexthop
device.
This will later allow us to test for the presence of this flag during
route lookup and dump.
Up until commit 4832c30d54 ("net: ipv6: put host and anycast routes on
device with address") host and anycast routes used the loopback netdev
as their nexthop device and thus were not marked with the 'linkdown'
flag. The patch preserves this behavior and allows one to ping the local
address even when the nexthop device does not have a carrier and the
'ignore_routes_with_linkdown' sysctl is set.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To make IPv6 more in line with IPv4 we need to be able to respond
differently to different netdev events. For example, when a netdev is
unregistered all the routes using it as their nexthop device should be
flushed, whereas when the netdev's carrier changes only the 'linkdown'
flag should be toggled.
Currently, this is not possible, as the function that traverses the
routing tables is not aware of the triggering event.
Propagate the triggering event down, so that it could be used in later
patches.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Previous patch marked nexthops with the 'dead' and 'linkdown' flags.
Clear these flags when the netdev comes back up.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
convert remaining users of rtnl_register to rtnl_register_module
and un-export rtnl_register.
Requested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This removes __rtnl_register and switches callers to either
rtnl_register or rtnl_register_module.
Also, rtnl_register() will now print an error if memory allocation
failed rather than panic the kernel.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
With commits 35e015e1f5 and a2d3f3e338, the global 'accept_dad' flag
is also taken into account (default value is 1). If either global or
per-interface flag is non-zero, DAD will be enabled on a given interface.
This is not backward compatible: before those patches, the user could
disable DAD just by setting the per-interface flag to 0. Now, the
user instead needs to set both flags to 0 to actually disable DAD.
Restore the previous behaviour by setting the default for the global
'accept_dad' flag to 0. This way, DAD is still enabled by default,
as per-interface flags are set to 1 on device creation, but setting
them to 0 is enough to disable DAD on a given interface.
- Before 35e015e1f57a7 and a2d3f3e33853:
global per-interface DAD enabled
[default] 1 1 yes
X 0 no
X 1 yes
- After 35e015e1f5 and a2d3f3e33853:
global per-interface DAD enabled
[default] 1 1 yes
0 0 no
0 1 yes
1 0 yes
- After this fix:
global per-interface DAD enabled
1 1 yes
0 0 no
[default] 0 1 yes
1 0 yes
Fixes: 35e015e1f5 ("ipv6: fix net.ipv6.conf.all interface DAD handlers")
Fixes: a2d3f3e338 ("ipv6: fix net.ipv6.conf.all.accept_dad behaviour for real")
CC: Stefano Brivio <sbrivio@redhat.com>
CC: Matteo Croce <mcroce@redhat.com>
CC: Erik Kline <ek@google.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a per-device sysctl to specify the default traffic class to use for
kernel originated IPv6 Neighbour Discovery packets.
Currently this includes:
- Router Solicitation (ICMPv6 type 133)
ndisc_send_rs() -> ndisc_send_skb() -> ip6_nd_hdr()
- Neighbour Solicitation (ICMPv6 type 135)
ndisc_send_ns() -> ndisc_send_skb() -> ip6_nd_hdr()
- Neighbour Advertisement (ICMPv6 type 136)
ndisc_send_na() -> ndisc_send_skb() -> ip6_nd_hdr()
- Redirect (ICMPv6 type 137)
ndisc_send_redirect() -> ndisc_send_skb() -> ip6_nd_hdr()
and if the kernel ever gets around to generating RA's,
it would presumably also include:
- Router Advertisement (ICMPv6 type 134)
(radvd daemon could pick up on the kernel setting and use it)
Interface drivers may examine the Traffic Class value and translate
the DiffServ Code Point into a link-layer appropriate traffic
prioritization scheme. An example of mapping IETF DSCP values to
IEEE 802.11 User Priority values can be found here:
https://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11
The expected primary use case is to properly prioritize ND over wifi.
Testing:
jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
0
jzem22:~# echo -1 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
-bash: echo: write error: Invalid argument
jzem22:~# echo 256 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
-bash: echo: write error: Invalid argument
jzem22:~# echo 0 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
jzem22:~# echo 255 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
255
jzem22:~# echo 34 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
34
jzem22:~# echo $[0xDC] > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
jzem22:~# tcpdump -v -i eth0 icmp6 and src host jzem22.pgc and dst host fe80::1
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
IP6 (class 0xdc, hlim 255, next-header ICMPv6 (58) payload length: 24)
jzem22.pgc > fe80::1: [icmp6 sum ok] ICMP6, neighbor advertisement,
length 24, tgt is jzem22.pgc, Flags [solicited]
(based on original change written by Erik Kline, with minor changes)
v2: fix 'suspicious rcu_dereference_check() usage'
by explicitly grabbing the rcu_read_lock.
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Erik Kline <ek@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IN6_ADDR_HSIZE is private to addrconf.c, move it here to avoid
confusion.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Smooth Cong Wang's bug fix into 'net-next'. Basically put
the bulk of the tcf_block_put() logic from 'net' into
tcf_block_put_ext(), but after the offload unbind.
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch updates the error messages displayed in kernel log to include
hwaddress of the source machine that caused ipv6 duplicate address
detection failures.
Examples:
a) When we receive a NA packet from another machine advertising our
address:
ICMPv6: NA: 34🆎cd:56:11:e8 advertised our address 2001:db8:: on eth0!
b) When we detect DAD failure during address assignment to an interface:
IPv6: eth0: IPv6 duplicate address 2001:db8:: used by 34🆎cd:56:11:e8
detected!
v2:
Changed %pI6 to %pI6c in ndisc_recv_na()
Chaged the v6 address in the commit message to 2001:db8::
Suggested-by: Igor Lubashev <ilubashe@akamai.com>
Signed-off-by: Vishwanath Pai <vpai@akamai.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rcu_read_lock() is enough here, no need to block BH.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Table is really RCU protected, no need to block BH
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rcu_read_lock() is enough here, no need to block BH.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rcu_read_lock() is enough here, as inet6_ifa_finish_destroy()
uses kfree_rcu()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bring IPv6 in par with IPv4 :
- Use net_hash_mix() to spread addresses a bit more.
- Use 256 slots hash table instead of 16
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6_add_addr_hash() can compute the hash value outside of
locked section and pass it to ipv6_chk_same_addr().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6_chk_same_addr() is only used by ipv6_add_addr_hash(),
so moving it avoids a forward declaration.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add extack to in_validator_info and in6_validator_info. Update the one
user of each, ipvlan, to return an error message for failures.
Only manual configuration of an address is plumbed in the IPv6 code path.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
inet6addr_validator chain was added by commit 3ad7d2468f ("Ipvlan
should return an error when an address is already in use") to allow
address validation before changes are committed and to be able to
fail the address change with an error back to the user. The address
validation is not done for addresses received from router
advertisements.
Handling RAs in softirq context is the only reason for the notifier
chain to be atomic versus blocking. Since the only current user, ipvlan,
of the validator chain ignores softirq context, the notifier can be made
blocking and simply not invoked for softirq path.
The blocking option is needed by spectrum for example to validate
resources for an adding an address to an interface.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6_add_addr is called in process context with rtnl lock held
(e.g., manual config of an address) or during softirq processing
(e.g., autoconf and address from a router advertisement).
Currently, ipv6_add_addr calls rcu_read_lock_bh shortly after entry
and does not call unlock until exit, minus the call around the address
validator notifier. Similarly, addrconf_hash_lock is taken after the
validator notifier and held until exit. This forces the allocation of
inet6_ifaddr to always be atomic.
Refactor ipv6_add_addr as follows:
1. add an input boolean to discriminate the call path (process context
or softirq). This new flag controls whether the alloc can be done
with GFP_KERNEL or GFP_ATOMIC.
2. Move the rcu_read_lock_bh and unlock calls only around functions that
do rcu updates.
3. Remove the in6_dev_hold and put added by 3ad7d2468f ("Ipvlan should
return an error when an address is already in use."). This was done
presumably because rcu_read_unlock_bh needs to be called before calling
the validator. Since rcu_read_lock is not needed before the validator
runs revert the hold and put added by 3ad7d2468f and only do the
hold when setting ifp->idev.
4. move duplicate address check and insertion of new address in the global
address hash into a helper. The helper is called after an ifa is
allocated and filled in.
This allows the ifa for manually configured addresses to be done with
GFP_KERNEL and reduces the overall amount of time with rcu_read_lock held
and hash table spinlock held.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to the previous patch, use the device lookup functions
that bump device refcount and flag this as DOIT_UNLOCKED to avoid
rtnl mutex.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of relying on rtnl mutex bump device reference count.
After this change, values reported can change in parallel, but thats not
much different from current state, as anyone can change the settings
right after rtnl_unlock (and before userspace processed reply).
While at it, switch to GFP_KERNEL allocation.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
By extending the rcu section a bit, we can avoid these
very expensive in6_ifa_put()/in6_ifa_hold() calls
done in __ipv6_dev_get_saddr() and ipv6_dev_get_saddr()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Callers hold rcu_read_lock(), so we do not need
the rcu_read_lock()/rcu_read_unlock() pair.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
inet6_ifa_finish_destroy() already uses kfree_rcu() to free
inet6_ifaddr structs.
We need to use proper list additions/deletions in order
to allow readers to use RCU instead of idev->lock rwlock.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 35e015e1f5 ("ipv6: fix net.ipv6.conf.all interface DAD handlers")
was intended to affect accept_dad flag handling in such a way that
DAD operation and mode on a given interface would be selected
according to the maximum value of conf/{all,interface}/accept_dad.
However, addrconf_dad_begin() checks for particular cases in which we
need to skip DAD, and this check was modified in the wrong way.
Namely, it was modified so that, if the accept_dad flag is 0 for the
given interface *or* for all interfaces, DAD would be skipped.
We have instead to skip DAD if accept_dad is 0 for the given interface
*and* for all interfaces.
Fixes: 35e015e1f5 ("ipv6: fix net.ipv6.conf.all interface DAD handlers")
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Reported-by: Erik Kline <ek@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With all the preparation work before, we are now ready to replace rwlock
with rcu and spinlock in fib6_table.
That means now all fib6_node in fib6_table are protected by rcu. And
when freeing fib6_node, call_rcu() is used to wait for the rcu grace
period before releasing the memory.
When accessing fib6_node, corresponding rcu APIs need to be used.
And all previous sessions protected by the write lock will now be
protected by the spin lock per table.
All previous sessions protected by read lock will now be protected by
rcu_read_lock().
A couple of things to note here:
1. As part of the work of replacing rwlock with rcu, the linked list of
fn->leaf now has to be rcu protected as well. So both fn->leaf and
rt->dst.rt6_next are now __rcu tagged and corresponding rcu APIs are
used when manipulating them.
2. For fn->rr_ptr, first of all, it also needs to be rcu protected now
and is tagged with __rcu and rcu APIs are used in corresponding places.
Secondly, fn->rr_ptr is changed in rt6_select() which is a reader
thread. This makes the issue a bit complicated. We think a valid
solution for it is to let rt6_select() grab the tb6_lock if it decides
to change it. As it is not in the normal operation and only happens when
there is no valid neighbor cache for the route, we think the performance
impact should be low.
3. fib6_walk_continue() has to be called with tb6_lock held even in the
route dumping related functions, e.g. inet6_dump_fib(),
fib6_tables_dump() and ipv6_route_seq_ops. It is because
fib6_walk_continue() makes modifications to the walker structure, and so
are fib6_repair_tree() and fib6_del_route(). In order to do proper
syncing between them, we need to let fib6_walk_continue() hold the lock.
We may be able to do further improvement on the way we do the tree walk
to get rid of the need for holding the spin lock. But not for now.
4. When fib6_del_route() removes a route from the tree, we no longer
mark rt->dst.rt6_next to NULL to make simultaneous reader be able to
further traverse the list with rcu. However, rt->dst.rt6_next is only
valid within this same rcu period. No one should access it later.
5. All the operation of atomic_inc(rt->rt6i_ref) is changed to be
performed before we publish this route (either by linking it to fn->leaf
or insert it in the list pointed by fn->leaf) just to be safe because as
soon as we publish the route, some read thread will be able to access it.
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With rwlock, it is safe to call dst_hold() in the read thread because
read thread is guaranteed to be separated from write thread.
However, after we replace rwlock with rcu, it is no longer safe to use
dst_hold(). A dst might already have been deleted but is waiting for the
rcu grace period to pass before freeing the memory when a read thread is
trying to do dst_hold(). This could potentially cause double free issue.
So this commit replaces all dst_hold() with dst_hold_safe() in all read
thread to avoid this double free issue.
And in order to make the code more compact, a new function ip6_hold_safe()
is introduced. It calls dst_hold_safe() first, and if that fails, it will
either fall back to hold and return net->ipv6.ip6_null_entry or set rt to
NULL according to the caller's need.
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David Ahern