diff options
Diffstat (limited to 'Documentation/networking/tc-actions-env-rules.txt')
| -rw-r--r-- | Documentation/networking/tc-actions-env-rules.txt | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/Documentation/networking/tc-actions-env-rules.txt b/Documentation/networking/tc-actions-env-rules.txt index 01e716d..dcadf6f 100644 --- a/Documentation/networking/tc-actions-env-rules.txt +++ b/Documentation/networking/tc-actions-env-rules.txt @@ -4,26 +4,27 @@ The "enviromental" 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 intentionaly branches by redirecting a packet then you need to +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 so much so that skb_act_clone() -resets them for you. So invoke skb_act_clone() rather than skb_clone() +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 dont own is a nono. You simply return +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 "enviromental" rules for callers of actions (qdiscs etc) are: -*) thou art responsible for freeing anything returned as being +*) 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 dont need to do anything. +returned, then all is great and you don't need to do anything. Post on netdev if something is unclear. |
