CODEWITHSUNDEEP
linux-device-driverkernel-module
lithiumhead
lithiumhead

Reputation: 871

How to block packets received by eth0 from going up to TCP/IP stack

We are using dev_add_pack with ETH_P_ALL to get copies of sk_buff of all ethernet frames received by eth1. Is there a way we can prevent eth1 from forwarding all the ethernet frames up to TCP/IP layer while still letting it capture all the frames and passing it on to our loadable kernel module?

Upvotes: 2

Views: 307

Answers (1)

Technologeeks
Technologeeks

Reputation: 7897

Your best bet is to create a netfilter hook. Rather than dev_add_pack, which gets a copy of the sk_buff (thereby allowing the original sk_buff to propagate up to the TCP/IP stack, a netfilter hook will give you the pointer to the original sk_buff as it traverses the stack, and your code actually executes as callback from the stack itself - so you can choose to block the packet, claim ownership in your module, or do pretty much anything on your mind.

Upvotes: 2

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