Fix/better handling of no-stats-tracking rules

[flowspec-xdp] / README.md

diff --git a/README.md b/README.md
index 2d96ec74c9c0e0b05cfe842cae19491cb9d1f58b..5f6e917d0f9115450f4ee311f1a12b217788dda1 100644 (file)
--- a/README.md
+++ b/README.md
@@ -15,9 +15,12 @@ provide rate-limiting on a per-source basis. When the upper two bytes in an exte
 0x8306 (rate in bytes) or 0x830c (rate in packets), we rate limit the same as 0x8006 or 0x800c
 except that the rate limit is applied per source address. The encoding mirrors the non-per-source
 encoding in that the last 4 octets are the floating-point rate limit. Instead of a 2 octet
-AS/ignored value, the third octet is the maximum number of source IPs tracked (plus one, times 1024)
+AS/ignored value, the third octet is the maximum number of source IPs tracked (plus one, times 4096)
 and the fourth octet is a prefix length mask, which is applied to the source IP before rate-limiting.
 
+See `collision_prob.py` for collision probabilities in the hash table to estimate the size you
+should use.
+
 `install.sh` provides a simple example script which will compile and install a generated XDP program
 from the rules in bird's `flowspec4` and `flowspec6` routing tables. It will drop any packets which
 match any flowspec filter.