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| author | Florian Westphal <fw@strlen.de> | 2023-10-11 09:59:38 +0200 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2023-10-18 10:26:43 +0200 |
| commit | e0d4593140b01b8da513a0c88c26da28b4906413 (patch) | |
| tree | 38aa2be18abfbdb974535a1530910a8b6c25cca2 /net/netfilter | |
| parent | 35c038b0a4be197679deefaf96998241cb7efc88 (diff) | |
| download | lwn-e0d4593140b01b8da513a0c88c26da28b4906413.tar.gz lwn-e0d4593140b01b8da513a0c88c26da28b4906413.zip | |
netfilter: make nftables drops visible in net dropmonitor
net_dropmonitor blames core.c:nf_hook_slow.
Add NF_DROP_REASON() helper and use it in nft_do_chain().
The helper releases the skb, so exact drop location becomes
available. Calling code will observe the NF_STOLEN verdict
instead.
Adjust nf_hook_slow so we can embed an erro value wih
NF_STOLEN verdicts, just like we do for NF_DROP.
After this, drop in nftables can be pinpointed to a drop due
to a rule or the chain policy.
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/core.c | 6 | ||||
| -rw-r--r-- | net/netfilter/nf_tables_core.c | 6 |
2 files changed, 8 insertions, 4 deletions
diff --git a/net/netfilter/core.c b/net/netfilter/core.c index ef4e76e5aef9..3126911f5042 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -639,10 +639,10 @@ int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, if (ret == 1) continue; return ret; + case NF_STOLEN: + return NF_DROP_GETERR(verdict); default: - /* Implicit handling for NF_STOLEN, as well as any other - * non conventional verdicts. - */ + WARN_ON_ONCE(1); return 0; } } diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index 6009b423f60a..8b536d7ef6c2 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -308,10 +308,11 @@ next_rule: switch (regs.verdict.code & NF_VERDICT_MASK) { case NF_ACCEPT: - case NF_DROP: case NF_QUEUE: case NF_STOLEN: return regs.verdict.code; + case NF_DROP: + return NF_DROP_REASON(pkt->skb, SKB_DROP_REASON_NETFILTER_DROP, EPERM); } switch (regs.verdict.code) { @@ -342,6 +343,9 @@ next_rule: if (static_branch_unlikely(&nft_counters_enabled)) nft_update_chain_stats(basechain, pkt); + if (nft_base_chain(basechain)->policy == NF_DROP) + return NF_DROP_REASON(pkt->skb, SKB_DROP_REASON_NETFILTER_DROP, EPERM); + return nft_base_chain(basechain)->policy; } EXPORT_SYMBOL_GPL(nft_do_chain); |