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authorMauro Carvalho Chehab <mchehab+huawei@kernel.org>2020-04-30 19:04:28 +0300
committerDavid S. Miller <davem@davemloft.net>2020-04-30 22:56:38 +0300
commitd2461edde7d15121a2cd39d48cd39edbd3fa019a (patch)
tree16d2dbb19a3877df27deb8c0c570e12c75cf480f /Documentation/networking/tc-actions-env-rules.rst
parent32c0f0bed5bb08625083ed7f5b661c842d63ebd1 (diff)
downloadlinux-d2461edde7d15121a2cd39d48cd39edbd3fa019a.tar.xz
docs: networking: convert tc-actions-env-rules.txt to ReST
- add SPDX header; - add a document title; - use the right numbered list markup; - adjust identation, whitespaces and blank lines where needed; - add to networking/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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+.. SPDX-License-Identifier: GPL-2.0
+
+================================
+TC Actions - Environmental Rules
+================================
+
+
+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.
+
+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.
+
+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.