1 files changed, 23 insertions, 0 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index ebc09a159f62..2b7cf19a06ad 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -46,6 +46,29 @@ ipfrag_secret_interval - INTEGER
         for the hash secret) for IP fragments.
         Default: 600
 
+ipfrag_max_dist - INTEGER
+        ipfrag_max_dist is a non-negative integer value which defines the 
+        maximum "disorder" which is allowed among fragments which share a 
+        common IP source address. Note that reordering of packets is 
+        not unusual, but if a large number of fragments arrive from a source 
+        IP address while a particular fragment queue remains incomplete, it 
+        probably indicates that one or more fragments belonging to that queue 
+        have been lost. When ipfrag_max_dist is positive, an additional check 
+        is done on fragments before they are added to a reassembly queue - if 
+        ipfrag_max_dist (or more) fragments have arrived from a particular IP 
+        address between additions to any IP fragment queue using that source 
+        address, it's presumed that one or more fragments in the queue are 
+        lost. The existing fragment queue will be dropped, and a new one 
+        started. An ipfrag_max_dist value of zero disables this check.
+
+        Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can
+        result in unnecessarily dropping fragment queues when normal
+        reordering of packets occurs, which could lead to poor application 
+        performance. Using a very large value, e.g. 50000, increases the 
+        likelihood of incorrectly reassembling IP fragments that originate 
+        from different IP datagrams, which could result in data corruption.
+        Default: 64
+
 INET peer storage:
 
 inet_peer_threshold - INTEGER