kernel/linux.git/include/net/ip_fib.h, branch v4.12.9

ipv4: add reference counting to metrics

2017-05-26T18:57:07+00:00

Andrey Konovalov reported crashes in ipv4_mtu() I could reproduce the issue with KASAN kernels, between 10.246.7.151 and 10.246.7.152 : 1) 20 concurrent netperf -t TCP_RR -H 10.246.7.152 -l 1000 & 2) At the same time run following loop : while : do ip ro add 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500 ip ro del 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500 done Cong Wang attempted to add back rt->fi in commit 82486aa6f1b9 ("ipv4: restore rt->fi for reference counting") but this proved to add some issues that were complex to solve. Instead, I suggested to add a refcount to the metrics themselves, being a standalone object (in particular, no reference to other objects) I tried to make this patch as small as possible to ease its backport, instead of being super clean. Note that we believe that only ipv4 dst need to take care of the metric refcount. But if this is wrong, this patch adds the basic infrastructure to extend this to other families. Many thanks to Julian Anastasov for reviewing this patch, and Cong Wang for his efforts on this problem. Fixes: 2860583fe840 ("ipv4: Kill rt->fi") Signed-off-by: Eric Dumazet Reported-by: Andrey Konovalov Reviewed-by: Julian Anastasov Acked-by: Cong Wang Signed-off-by: David S. Miller

net: ipv4: add support for ECMP hash policy choice

2017-03-21T22:27:19+00:00

This patch adds support for ECMP hash policy choice via a new sysctl called fib_multipath_hash_policy and also adds support for L4 hashes. The current values for fib_multipath_hash_policy are: 0 - layer 3 (default) 1 - layer 4 If there's an skb hash already set and it matches the chosen policy then it will be used instead of being calculated (currently only for L4). In L3 mode we always calculate the hash due to the ICMP error special case, the flow dissector's field consistentification should handle the address order thus we can remove the address reversals. If the skb is provided we always use it for the hash calculation, otherwise we fallback to fl4, that is if skb is NULL fl4 has to be set. Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller

ipv4: fib_rules: Add notifier info to FIB rules notifications

2017-03-16T17:18:33+00:00

Whenever a FIB rule is added or removed, a notification is sent in the FIB notification chain. However, listeners don't have a way to tell which rule was added or removed. This is problematic as we would like to give listeners the ability to decide which action to execute based on the notified rule. Specifically, offloading drivers should be able to determine if they support the reflection of the notified FIB rule and flush their LPM tables in case they don't. Do that by adding a notifier info to these notifications and embed the common FIB rule struct in it. Signed-off-by: Ido Schimmel Acked-by: David Ahern Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller

ipv4: fib_rules: Check if rule is a default rule

2017-03-16T17:18:33+00:00

Currently, when non-default (custom) FIB rules are used, devices capable of layer 3 offloading flush their tables and let the kernel do the forwarding instead. When these devices' drivers are loaded they register to the FIB notification chain, which lets them know about the existence of any custom FIB rules. This is done by sending a RULE_ADD notification based on the value of 'net->ipv4.fib_has_custom_rules'. This approach is problematic when VRF offload is taken into account, as upon the creation of the first VRF netdev, a l3mdev rule is programmed to direct skbs to the VRF's table. Instead of merely reading the above value and sending a single RULE_ADD notification, we should iterate over all the FIB rules and send a detailed notification for each, thereby allowing offloading drivers to sanitize the rules they don't support and potentially flush their tables. While l3mdev rules are uniquely marked, the default rules are not. Therefore, when they are being notified they might invoke offloading drivers to unnecessarily flush their tables. Solve this by adding an helper to check if a FIB rule is a default rule. Namely, its selector should match all packets and its action should point to the local, main or default tables. As noted by David Ahern, uniquely marking the default rules is insufficient. When using VRFs, it's common to avoid false hits by moving the rule for the local table to just before the main table: Default configuration: $ ip rule show 0: from all lookup local 32766: from all lookup main 32767: from all lookup default Common configuration with VRFs: $ ip rule show 1000: from all lookup [l3mdev-table] 32765: from all lookup local 32766: from all lookup main 32767: from all lookup default Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller

ipv4: fib: Remove redundant argument

2017-03-10T17:45:09+00:00

We always pass the same event type to fib_notify() and fib_rules_notify(), so we can safely drop this argument. Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller

ipv4: fib: Move FIB notification code to a separate file

2017-03-10T17:45:09+00:00

Most of the code concerned with the FIB notification chain currently resides in fib_trie.c, but this isn't really appropriate, as the FIB notification chain is also used for FIB rules. Therefore, it makes sense to move the common FIB notification code to a separate file and have it export the relevant functions, which can be invoked by its different users (e.g., fib_trie.c, fib_rules.c). Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller

ipv4: fib: Add events for FIB replace and append

2017-02-10T16:32:13+00:00

The FIB notification chain currently uses the NLM_F_{REPLACE,APPEND} flags to signal routes being replaced or appended. Instead of using netlink flags for in-kernel notifications we can simply introduce two new events in the FIB notification chain. This has the added advantage of making the API cleaner, thereby making it clear that these events should be supported by listeners of the notification chain. Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko CC: Patrick McHardy Signed-off-by: David S. Miller

ipv4: fib: Notify about nexthop status changes

2017-02-08T20:25:18+00:00

When a multipath route is hit the kernel doesn't consider nexthops that are DEAD or LINKDOWN when IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN is set. Devices that offload multipath routes need to be made aware of nexthop status changes. Otherwise, the device will keep forwarding packets to non-functional nexthops. Add the FIB_EVENT_NH_{ADD,DEL} events to the fib notification chain, which notify capable devices when they should add or delete a nexthop from their tables. Cc: Roopa Prabhu Cc: David Ahern Cc: Andy Gospodarek Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Reviewed-by: Andy Gospodarek Signed-off-by: David S. Miller

net: ipv4: make fib_select_default static

2017-01-06T20:57:50+00:00

fib_select_default has a single caller within the same file. Make it static. Signed-off-by: David Ahern Signed-off-by: David S. Miller

ipv4: fib: Replay events when registering FIB notifier

2016-12-04T00:29:35+00:00

Commit b90eb7549499 ("fib: introduce FIB notification infrastructure") introduced a new notification chain to notify listeners (f.e., switchdev drivers) about addition and deletion of routes. However, upon registration to the chain the FIB tables can already be populated, which means potential listeners will have an incomplete view of the tables. Solve that by dumping the FIB tables and replaying the events to the passed notification block. The dump itself is done using RCU in order not to starve consumers that need RTNL to make progress. The integrity of the dump is ensured by reading the FIB change sequence counter before and after the dump under RTNL. This allows us to avoid the problematic situation in which the dumping process sends a ENTRY_ADD notification following ENTRY_DEL generated by another process holding RTNL. Callers of the registration function may pass a callback that is executed in case the dump was inconsistent with current FIB tables. The number of retries until a consistent dump is achieved is set to a fixed number to prevent callers from looping for long periods of time. In case current limit proves to be problematic in the future, it can be easily converted to be configurable using a sysctl. Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller