CODEWITHSUNDEEP
clinuxkernelnetlink
alexandernst
alexandernst

Reputation: 15099

Size of data send via NetLink

I'm trying to get the size of a chunk of data sent via NetLink (Linux Kernel). I have tried with size = nlh->nlmsg_len - NLMSG_HDRLEN, but that isn't returning the correct size. What's the correct way to get the message's data size?

Upvotes: 0

Views: 742

Answers (1)

jørgensen
jørgensen

Reputation: 10579

Why would you believe nlh->nlmsg_len - NLMSG_HDRLEN is not returning the {message size without header} for the message you are looking at? If nlmsg_len contains, for example, the value 16 (that's what NLMSG_HDRLEN should be), then the payload of this message is empty. Your buffer may have more messages in it that want to be read.

As a side note, I recommend you use libmnl for Netlink message parsing and construction.

Upvotes: 2

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