From 39d08b91646d83e87f7cbcd846b3ef33b1a53b79 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 9 Oct 2023 11:26:55 +0200 Subject: [PATCH] net, sched: Add tcf_set_drop_reason for {__,}tcf_classify Add an initial user for the newly added tcf_set_drop_reason() helper to set the drop reason for internal errors leading to TC_ACT_SHOT inside {__,}tcf_classify(). Right now this only adds a very basic SKB_DROP_REASON_TC_ERROR as a generic fallback indicator to mark drop locations. Where needed, such locations can be converted to more specific codes, for example, when hitting the reclassification limit, etc. Signed-off-by: Daniel Borkmann Cc: Jamal Hadi Salim Cc: Victor Nogueira Link: https://lore.kernel.org/r/20231009092655.22025-2-daniel@iogearbox.net Signed-off-by: Jakub Kicinski --- include/net/dropreason-core.h | 3 +++ net/sched/cls_api.c | 26 ++++++++++++++++++++------ 2 files changed, 23 insertions(+), 6 deletions(-) diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index a587e83fc169..845dce805de7 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -80,6 +80,7 @@ FN(IPV6_NDISC_BAD_OPTIONS) \ FN(IPV6_NDISC_NS_OTHERHOST) \ FN(QUEUE_PURGE) \ + FN(TC_ERROR) \ FNe(MAX) /** @@ -345,6 +346,8 @@ enum skb_drop_reason { SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST, /** @SKB_DROP_REASON_QUEUE_PURGE: bulk free. */ SKB_DROP_REASON_QUEUE_PURGE, + /** @SKB_DROP_REASON_TC_ERROR: generic internal tc error. */ + SKB_DROP_REASON_TC_ERROR, /** * @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which * shouldn't be used as a real 'reason' - only for tracing code gen diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index a193cc7b3241..1daeb2182b70 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -1681,12 +1681,16 @@ reclassify: * time we got here with a cookie from hardware. */ if (unlikely(n->tp != tp || n->tp->chain != n->chain || - !tp->ops->get_exts)) + !tp->ops->get_exts)) { + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; + } exts = tp->ops->get_exts(tp, n->handle); - if (unlikely(!exts || n->exts != exts)) + if (unlikely(!exts || n->exts != exts)) { + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; + } n = NULL; err = tcf_exts_exec_ex(skb, exts, act_index, res); @@ -1712,8 +1716,10 @@ reclassify: return err; } - if (unlikely(n)) + if (unlikely(n)) { + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; + } return TC_ACT_UNSPEC; /* signal: continue lookup */ #ifdef CONFIG_NET_CLS_ACT @@ -1723,6 +1729,7 @@ reset: tp->chain->block->index, tp->prio & 0xffff, ntohs(tp->protocol)); + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; } @@ -1759,8 +1766,10 @@ int tcf_classify(struct sk_buff *skb, if (ext->act_miss) { n = tcf_exts_miss_cookie_lookup(ext->act_miss_cookie, &act_index); - if (!n) + if (!n) { + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; + } chain = n->chain_index; } else { @@ -1768,8 +1777,10 @@ int tcf_classify(struct sk_buff *skb, } fchain = tcf_chain_lookup_rcu(block, chain); - if (!fchain) + if (!fchain) { + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; + } /* Consume, so cloned/redirect skbs won't inherit ext */ skb_ext_del(skb, TC_SKB_EXT); @@ -1788,8 +1799,11 @@ int tcf_classify(struct sk_buff *skb, struct tc_skb_cb *cb = tc_skb_cb(skb); ext = tc_skb_ext_alloc(skb); - if (WARN_ON_ONCE(!ext)) + if (WARN_ON_ONCE(!ext)) { + tcf_set_drop_reason(res, SKB_DROP_REASON_TC_ERROR); return TC_ACT_SHOT; + } + ext->chain = last_executed_chain; ext->mru = cb->mru; ext->post_ct = cb->post_ct;