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author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-26 08:43:05 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-26 08:43:05 -0700 |
commit | ec3b67c11df42362ccda81261d62829042f223f0 (patch) | |
tree | ab66bc43d98e38eda7162f76208993b2280f88f3 /Documentation/networking/tc-actions-env-rules.txt | |
parent | e868171a94b637158a3930c9adfb448d0df163cd (diff) | |
parent | 4be2700fb7b95f2a7cef9324879cafccab8774fc (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (32 commits)
[NetLabel]: correct usage of RCU locking
[TCP]: fix D-SACK cwnd handling
[NET] napi: use non-interruptible sleep in napi_disable
[SCTP] net/sctp/auth.c: make 3 functions static
[TCP]: Add missing I/O AT code to ipv6 side.
[SCTP]: #if 0 sctp_update_copy_cksum()
[INET]: Unexport icmpmsg_statistics
[NET]: Unexport sock_enable_timestamp().
[TCP]: Make tcp_match_skb_to_sack() static.
[IRDA]: Make ircomm_tty static.
[NET] fs/proc/proc_net.c: make a struct static
[NET] dev_change_name: ignore changes to same name
[NET]: Document some simple rules for actions
[NET_CLS_ACT]: Use skb_act_clone
[NET_CLS_ACT]: Introduce skb_act_clone
[TCP]: Fix scatterlist handling in MD5 signature support.
[IPSEC]: Fix scatterlist handling in skb_icv_walk().
[IPSEC]: Add missing sg_init_table() calls to ESP.
[CRYPTO]: Initialize TCRYPT on-stack scatterlist objects correctly.
[CRYPTO]: HMAC needs some more scatterlist fixups.
...
Diffstat (limited to 'Documentation/networking/tc-actions-env-rules.txt')
-rw-r--r-- | Documentation/networking/tc-actions-env-rules.txt | 29 |
1 files changed, 29 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 00000000000..01e716d185f --- /dev/null +++ b/Documentation/networking/tc-actions-env-rules.txt @@ -0,0 +1,29 @@ + +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 +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() + +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 +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 +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. + +Post on netdev if something is unclear. + |