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| -rw-r--r-- | Documentation/networking/tc-actions-env-rules.rst | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/networking/tc-actions-env-rules.rst b/Documentation/networking/tc-actions-env-rules.rst new file mode 100644 index 000000000..86884b8fb --- /dev/null +++ b/Documentation/networking/tc-actions-env-rules.rst @@ -0,0 +1,29 @@ +.. 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. |