summaryrefslogtreecommitdiff
path: root/Documentation/networking/tc-actions-env-rules.txt
diff options
context:
space:
mode:
authorSrikant Patnaik2015-01-11 12:28:04 +0530
committerSrikant Patnaik2015-01-11 12:28:04 +0530
commit871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch)
tree8718f573808810c2a1e8cb8fb6ac469093ca2784 /Documentation/networking/tc-actions-env-rules.txt
parent9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff)
downloadFOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.gz
FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.bz2
FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.zip
Moved, renamed, and deleted files
The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure.
Diffstat (limited to 'Documentation/networking/tc-actions-env-rules.txt')
-rw-r--r--Documentation/networking/tc-actions-env-rules.txt30
1 files changed, 30 insertions, 0 deletions
diff --git a/Documentation/networking/tc-actions-env-rules.txt b/Documentation/networking/tc-actions-env-rules.txt
new file mode 100644
index 00000000..70d6cf60
--- /dev/null
+++ b/Documentation/networking/tc-actions-env-rules.txt
@@ -0,0 +1,30 @@
+
+The "environmental" rules for authors of any new tc actions are:
+
+1) If you stealeth or borroweth any packet thou shalt be branching
+from the righteous path and thou shalt cloneth.
+
+For example if your action queues a packet to be processed later,
+or intentionally branches by redirecting a packet, then you need to
+clone the packet.
+
+There are certain fields in the skb tc_verd that need to be reset so we
+avoid loops, etc. A few are generic enough that skb_act_clone()
+resets them for you, so invoke skb_act_clone() rather than skb_clone().
+
+2) If you munge any packet thou shalt call pskb_expand_head in the case
+someone else is referencing the skb. After that you "own" the skb.
+You must also tell us if it is ok to munge the packet (TC_OK2MUNGE),
+this way any action downstream can stomp on the packet.
+
+3) Dropping packets you don't own is a no-no. You simply return
+TC_ACT_SHOT to the caller and they will drop it.
+
+The "environmental" rules for callers of actions (qdiscs etc) are:
+
+*) Thou art responsible for freeing anything returned as being
+TC_ACT_SHOT/STOLEN/QUEUED. If none of TC_ACT_SHOT/STOLEN/QUEUED is
+returned, then all is great and you don't need to do anything.
+
+Post on netdev if something is unclear.
+