Hi, I started to write a new TC action (ACT_CSUM) in order to be able to force a checksum update after a packet alteration done with ACT_PEDIT. I would like to provide this action at least on IPv4 and IPv6. My first solution wasn't to try to discover the network protocol (IPv4, IPv6 or another one) used inside the struct sk_buff argument got when the TC actions are called. I preferred to let the user specify the assumed network protocol when the TC action is defined using iproute2/tc. However, I discover after (it's my first work in the network Linux source code ;-) the struct sk_buff has a .protocol member which could contain the ETH_P_IP or ETH_P_IPV6 values according to the network protocol. Good news, I could use this member to avoid to ask the users to give an assumed network protocol ... but, As this .protocol member seems to be used at different moments when a packet is received, forwared or sent, and could contain something like ETH_P_8021Q which isn't a network protocol Id, can we say the struct sk_buff .protocol member is guaranteed to contain a network protocol Id in the struct sb_buff used in the TC action executions ? Maybe another way exsits to "discover" the network protocol used in the TC actions case. With the same idea, checking the other TC actions, I suppose the struct sk_buff .len member contains the network layer length (header+data(+trailer)). Is it a mistake from me ? Thanks in advance. Regards, Grégoire Baron -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
