kernel/linux.git/net/sched/act_api.c, branch v6.7

net, sched: Fix SKB_NOT_DROPPED_YET splat under debug config

2023-11-06T08:56:25+00:00

Getting the following splat [1] with CONFIG_DEBUG_NET=y and this reproducer [2]. Problem seems to be that classifiers clear 'struct tcf_result::drop_reason', thereby triggering the warning in __kfree_skb_reason() due to reason being 'SKB_NOT_DROPPED_YET' (0). Fixed by disambiguating a legit error from a verdict with a bogus drop_reason [1] WARNING: CPU: 0 PID: 181 at net/core/skbuff.c:1082 kfree_skb_reason+0x38/0x130 Modules linked in: CPU: 0 PID: 181 Comm: mausezahn Not tainted 6.6.0-rc6-custom-ge43e6d9582e0 #682 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc37 04/01/2014 RIP: 0010:kfree_skb_reason+0x38/0x130 [...] Call Trace: __netif_receive_skb_core.constprop.0+0x837/0xdb0 __netif_receive_skb_one_core+0x3c/0x70 process_backlog+0x95/0x130 __napi_poll+0x25/0x1b0 net_rx_action+0x29b/0x310 __do_softirq+0xc0/0x29b do_softirq+0x43/0x60 [2] ip link add name veth0 type veth peer name veth1 ip link set dev veth0 up ip link set dev veth1 up tc qdisc add dev veth1 clsact tc filter add dev veth1 ingress pref 1 proto all flower dst_mac 00:11:22:33:44:55 action drop mausezahn veth0 -a own -b 00:11:22:33:44:55 -q -c 1 Ido reported: [...] getting the following splat [1] with CONFIG_DEBUG_NET=y and this reproducer [2]. Problem seems to be that classifiers clear 'struct tcf_result::drop_reason', thereby triggering the warning in __kfree_skb_reason() due to reason being 'SKB_NOT_DROPPED_YET' (0). [...] [1] WARNING: CPU: 0 PID: 181 at net/core/skbuff.c:1082 kfree_skb_reason+0x38/0x130 Modules linked in: CPU: 0 PID: 181 Comm: mausezahn Not tainted 6.6.0-rc6-custom-ge43e6d9582e0 #682 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc37 04/01/2014 RIP: 0010:kfree_skb_reason+0x38/0x130 [...] Call Trace: __netif_receive_skb_core.constprop.0+0x837/0xdb0 __netif_receive_skb_one_core+0x3c/0x70 process_backlog+0x95/0x130 __napi_poll+0x25/0x1b0 net_rx_action+0x29b/0x310 __do_softirq+0xc0/0x29b do_softirq+0x43/0x60 [2] #!/bin/bash ip link add name veth0 type veth peer name veth1 ip link set dev veth0 up ip link set dev veth1 up tc qdisc add dev veth1 clsact tc filter add dev veth1 ingress pref 1 proto all flower dst_mac 00:11:22:33:44:55 action drop mausezahn veth0 -a own -b 00:11:22:33:44:55 -q -c 1 What happens is that inside most classifiers the tcf_result is copied over from a filter template e.g. *res = f->res which then implicitly overrides the prior SKB_DROP_REASON_TC_{INGRESS,EGRESS} default drop code which was set via sch_handle_{ingress,egress}() for kfree_skb_reason(). Commit text above copied verbatim from Daniel. The general idea of the patch is not very different from what Ido originally posted but instead done at the cls_api codepath. Fixes: 54a59aed395c ("net, sched: Make tc-related drop reason more flexible") Reported-by: Ido Schimmel Signed-off-by: Jamal Hadi Salim Link: https://lore.kernel.org/netdev/ZTjY959R+AFXf3Xy@shredder Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net: sched: Replace strlcpy with strscpy

2023-07-10T07:23:53+00:00

strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated [1]. In an effort to remove strlcpy() completely [2], replace strlcpy() here with strscpy(). Direct replacement is safe here since return value of -errno is used to check for truncation instead of sizeof(dest). [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [2] https://github.com/KSPP/linux/issues/89 Signed-off-by: Azeem Shaikh Reviewed-by: Pavan Chebbi Signed-off-by: David S. Miller

net/sched: act_api: use the correct TCA_ACT attributes in dump

2023-03-23T08:39:08+00:00

4 places in the act api code are using 'TCA_' definitions where they should be using 'TCA_ACT_', which is confusing for the reader, although functionally they are equivalent. Cc: Hangbin Liu Reviewed-by: Jamal Hadi Salim Reviewed-by: Simon Horman Signed-off-by: Pedro Tammela Acked-by: Hangbin Liu Signed-off-by: David S. Miller

net/sched: act_api: add specific EXT_WARN_MSG for tc action

2023-03-17T04:25:45+00:00

In my previous commit 0349b8779cc9 ("sched: add new attr TCA_EXT_WARN_MSG to report tc extact message") I didn't notice the tc action use different enum with filter. So we can't use TCA_EXT_WARN_MSG directly for tc action. Let's add a TCA_ROOT_EXT_WARN_MSG for tc action specifically and put this param before going to the TCA_ACT_TAB nest. Fixes: 0349b8779cc9 ("sched: add new attr TCA_EXT_WARN_MSG to report tc extact message") Signed-off-by: Hangbin Liu Acked-by: Jamal Hadi Salim Signed-off-by: Jakub Kicinski

Revert "net/sched: act_api: move TCA_EXT_WARN_MSG to the correct hierarchy"

2023-03-17T04:25:45+00:00

This reverts commit 923b2e30dc9cd05931da0f64e2e23d040865c035. This is not a correct fix as TCA_EXT_WARN_MSG is not a hierarchy to TCA_ACT_TAB. I didn't notice the TC actions use different enum when adding TCA_EXT_WARN_MSG. To fix the difference I will add a new WARN enum in TCA_ROOT_MAX as Jamal suggested. Signed-off-by: Hangbin Liu Acked-by: Jamal Hadi Salim Signed-off-by: Jakub Kicinski

net/sched: act_api: move TCA_EXT_WARN_MSG to the correct hierarchy

2023-02-27T12:16:34+00:00

TCA_EXT_WARN_MSG is currently sitting outside of the expected hierarchy for the tc actions code. It should sit within TCA_ACT_TAB. Fixes: 0349b8779cc9 ("sched: add new attr TCA_EXT_WARN_MSG to report tc extact message") Reviewed-by: Jamal Hadi Salim Signed-off-by: Pedro Tammela Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net/sched: cls_api: Support hardware miss to tc action

2023-02-21T00:46:10+00:00

For drivers to support partial offload of a filter's action list, add support for action miss to specify an action instance to continue from in sw. CT action in particular can't be fully offloaded, as new connections need to be handled in software. This imposes other limitations on the actions that can be offloaded together with the CT action, such as packet modifications. Assign each action on a filter's action list a unique miss_cookie which drivers can then use to fill action_miss part of the tc skb extension. On getting back this miss_cookie, find the action instance with relevant cookie and continue classifying from there. Signed-off-by: Paul Blakey Reviewed-by: Jiri Pirko Reviewed-by: Simon Horman Reviewed-by: Marcelo Ricardo Leitner Acked-by: Jamal Hadi Salim Signed-off-by: Jakub Kicinski

net/sched: Rename user cookie and act cookie

2023-02-21T00:46:10+00:00

struct tc_action->act_cookie is a user defined cookie, and the related struct flow_action_entry->act_cookie is used as an handle similar to struct flow_cls_offload->cookie. Rename tc_action->act_cookie to user_cookie, and flow_action_entry->act_cookie to cookie so their names would better fit their usage. Signed-off-by: Paul Blakey Reviewed-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski

net/sched: support per action hw stats

2023-02-14T10:00:01+00:00

There are currently two mechanisms for populating hardware stats: 1. Using flow_offload api to query the flow's statistics. The api assumes that the same stats values apply to all the flow's actions. This assumption breaks when action drops or jumps over following actions. 2. Using hw_action api to query specific action stats via a driver callback method. This api assures the correct action stats for the offloaded action, however, it does not apply to the rest of the actions in the flow's actions array. Extend the flow_offload stats callback to indicate that a per action stats update is required. Use the existing flow_offload_action api to query the action's hw stats. In addition, currently the tc action stats utility only updates hw actions. Reuse the existing action stats cb infrastructure to query any action stats. Signed-off-by: Oz Shlomo Reviewed-by: Simon Horman Reviewed-by: Marcelo Ricardo Leitner Acked-by: Jamal Hadi Salim Signed-off-by: Paolo Abeni

net/sched: introduce flow_offload action cookie

2023-02-14T10:00:01+00:00

Currently a hardware action is uniquely identified by the tuple. However, the id is set by the flow_act_setup callback and tc core cannot enforce this, and it is possible that a future change could break this. In addition, are not unique across network namespaces. Uniquely identify the action by setting an action cookie by the tc core. Use the unique action cookie to query the action's hardware stats. Signed-off-by: Oz Shlomo Reviewed-by: Simon Horman Reviewed-by: Marcelo Ricardo Leitner Acked-by: Jamal Hadi Salim Signed-off-by: Paolo Abeni