Add support for atomically upating a nexthop config.
When updating a nexthop, walk the lists of associated fib entries and
verify the new config is valid. Replace is done by swapping nh_info
for single nexthops - new config is applied to old nexthop struct, and
old config is moved to new nexthop struct. For nexthop groups the same
applies but for nh_group. In addition for groups the nh_parent reference
needs to be updated. The old config is released by calling __remove_nexthop
on the 'new' nexthop which now has the old config. This is done to avoid
messing around with the list_heads that track which fib entries are
using the nexthop.
After the swap of config data, bump the sequence counters for FIB entries
to invalidate any dst entries and send notifications to userspace. The
notifications include the new nexthop spec as well as any fib entries
using the updated nexthop struct.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IPv6 has traditionally had a single fib6_nh per fib6_info. With
nexthops we can have multiple fib6_nh associated with a fib6_info.
Add a nexthop helper to invoke a callback for each fib6_nh in a
'struct nexthop'. If the callback returns non-0, the loop is
stopped and the return value passed to the caller.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add struct nexthop and nh_list list_head to fib6_info. nh_list is the
fib6_info side of the nexthop <-> fib_info relationship. Since a fib6_info
referencing a nexthop object can not have 'sibling' entries (the old way
of doing multipath routes), the nh_list is a union with fib6_siblings.
Add f6i_list list_head to 'struct nexthop' to track fib6_info entries
using a nexthop instance. Update __remove_nexthop_fib to walk f6_list
and delete fib entries using the nexthop.
Add a few nexthop helpers for use when a nexthop is added to fib6_info:
- nexthop_fib6_nh - return first fib6_nh in a nexthop object
- fib6_info_nh_dev moved to nexthop.h and updated to use nexthop_fib6_nh
if the fib6_info references a nexthop object
- nexthop_path_fib6_result - similar to ipv4, select a path within a
multipath nexthop object. If the nexthop is a blackhole, set
fib6_result type to RTN_BLACKHOLE, and set the REJECT flag
Update the fib6_info references to check for nh and take a different path
as needed:
- rt6_qualify_for_ecmp - if a fib entry uses a nexthop object it can NOT
be coalesced with other fib entries into a multipath route
- rt6_duplicate_nexthop - use nexthop_cmp if either fib6_info references
a nexthop
- addrconf (host routes), RA's and info entries (anything configured via
ndisc) does not use nexthop objects
- fib6_info_destroy_rcu - put reference to nexthop object
- fib6_purge_rt - drop fib6_info from f6i_list
- fib6_select_path - update to use the new nexthop_path_fib6_result when
fib entry uses a nexthop object
- rt6_device_match - update to catch use of nexthop object as a blackhole
and set fib6_type and flags.
- ip6_route_info_create - don't add space for fib6_nh if fib entry is
going to reference a nexthop object, take a reference to nexthop object,
disallow use of source routing
- rt6_nlmsg_size - add space for RTA_NH_ID
- add rt6_fill_node_nexthop to add nexthop data on a dump
As with ipv4, most of the changes push existing code into the else branch
of whether the fib entry uses a nexthop object.
Update the nexthop code to walk f6i_list on a nexthop deleted to remove
fib entries referencing it.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add 'struct nexthop' and nh_list list_head to fib_info. nh_list is the
fib_info side of the nexthop <-> fib_info relationship.
Add fi_list list_head to 'struct nexthop' to track fib_info entries
using a nexthop instance. Add __remove_nexthop_fib and add it to
__remove_nexthop to walk the new list_head and mark those fib entries
as dead when the nexthop is deleted.
Add a few nexthop helpers for use when a nexthop is added to fib_info:
- nexthop_cmp to determine if 2 nexthops are the same
- nexthop_path_fib_result to select a path for a multipath
'struct nexthop'
- nexthop_fib_nhc to select a specific fib_nh_common within a
multipath 'struct nexthop'
Update existing fib_info_nhc to use nexthop_fib_nhc if a fib_info uses
a 'struct nexthop', and mark fib_info_nh as only used for the non-nexthop
case.
Update the fib_info functions to check for fi->nh and take a different
path as needed:
- free_fib_info_rcu - put the nexthop object reference
- fib_release_info - remove the fib_info from the nexthop's fi_list
- nh_comp - use nexthop_cmp when either fib_info references a nexthop
object
- fib_info_hashfn - use the nexthop id for the hashing vs the oif of
each fib_nh in a fib_info
- fib_nlmsg_size - add space for the RTA_NH_ID attribute
- fib_create_info - verify nexthop reference can be taken, verify
nexthop spec is valid for fib entry, and add fib_info to fi_list for
a nexthop
- fib_select_multipath - use the new nexthop_path_fib_result to select a
path when nexthop objects are used
- fib_table_lookup - if the 'struct nexthop' is a blackhole nexthop, treat
it the same as a fib entry using 'blackhole'
The bulk of the changes are in fib_semantics.c and most of that is
moving the existing change_nexthops into an else branch.
Update the nexthop code to walk fi_list on a nexthop deleted to remove
fib entries referencing it.
Signed-off-by: David Ahern <dsahern@gmail.com>
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>
The variable err is initialized with a value that is never read
and err is reassigned a few statements later. This initialization
is redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow the creation of nexthop groups which reference other nexthop
objects to create multipath routes:
+--------------+
+------------+ +--------------+ |
| nh nh_grp --->| nh_grp_entry |-+
+------------+ +---------|----+
^ | | +------------+
+----------------+ +--->| nh, weight |
nh_parent +------------+
A group entry points to a nexthop with a weight for that hop within the
group. The nexthop has a list_head, grp_list, for tracking which groups
it is a member of and the group entry has a reference back to the parent.
The grp_list is used when a nexthop is deleted - to efficiently remove
it from groups using it.
If a nexthop group spec is given, no other attributes can be set. Each
nexthop id in a group spec must already exist.
Similar to single nexthops, the specification of a nexthop group can be
updated so that data is managed with rcu locking.
Add path selection function to account for multiple paths and add
ipv{4,6}_good_nh helpers to know that if a neighbor entry exists it is
in a good state.
Update NETDEV event handling to rebalance multipath nexthop groups if
a nexthop is deleted due to a link event (down or unregister).
When a nexthop is removed any groups using it are updated. Groups using a
nexthop a tracked via a grp_list.
Nexthop dumps can be limited to groups only by adding NHA_GROUPS to the
request.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for NHA_ENCAP and NHA_ENCAP_TYPE. Leverages the existing code
for lwtunnel within fib_nh_common, so the only change needed is handling
the attributes in the nexthop code.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Handle IPv6 gateway in a nexthop spec. If nh_family is set to AF_INET6,
NHA_GATEWAY is expected to be an IPv6 address. Add ipv6 option to gw in
nh_config to hold the address, add fib6_nh to nh_info to leverage the
ipv6 initialization and cleanup code. Update nh_fill_node to dump the v6
address.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for IPv4 nexthops. If nh_family is set to AF_INET, then
NHA_GATEWAY is expected to be an IPv4 address.
Register for netdev events to be notified of admin up/down changes as
well as deletes. A hash table is used to track nexthop per devices to
quickly convert device events to the affected nexthops.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Barebones start point for nexthops. Implementation for RTM commands,
notifications, management of rbtree for holding nexthops by id, and
kernel side data structures for nexthops and nexthop config.
Nexthops are maintained in an rbtree sorted by id. Similar to routes,
nexthops are configured per namespace using netns_nexthop struct added
to struct net.
Nexthop notifications are sent when a nexthop is added or deleted,
but NOT if the delete is due to a device event or network namespace
teardown (which also involves device events). Applications are
expected to use the device down event to flush nexthops and any
routes used by the nexthops.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David Ahern