From 5deec25ddf60effe52ac91572c5e98114d95d2bd Mon Sep 17 00:00:00 2001 From: Christian Deacon Date: Sat, 25 Jul 2020 14:58:13 +0000 Subject: [PATCH] Added another note to README. --- README.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/README.md b/README.md index 9314d43..83099de 100644 --- a/README.md +++ b/README.md @@ -64,6 +64,8 @@ The config option `icmpopts` within a filter is an array including ICMP options. **Note** - Everything besides the main `enabled` and `action` options within a filter are **not** required. This means you do not have to define them within your config. +**Note** - As of right now, you can specify up to 55 maximum filters. This is due to the BPF map's max entries limitation while using `BPF_MAP_TYPE_ARRAY`. I don't believe we'd be able to use a per-CPU map for this as well because if we do, I don't believe we'd be able to reliably read the filters within the XDP program. If you want more filters, you could try using a hash map (changing the filter map's type to `BPF_MAP_TYPE_HASH`), but keep in mind lookups on the filters will be slower. + ## Configuration Example Here's an example of a config: