netlink: Introduce nlmsg_payload helper

Create a new helper function, nlmsg_payload(), to simplify checking and
retrieving Netlink message payloads.

This reduces boilerplate code for users who need to verify the message
length before accessing its data.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250414-nlmsg-v2-1-3d90cb42c6af@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Breno Leitao
2025-04-14 06:24:07 -07:00
committed by Jakub Kicinski
parent 0418711f60
commit 95d06e92a4

View File

@@ -611,6 +611,22 @@ static inline int nlmsg_len(const struct nlmsghdr *nlh)
return nlh->nlmsg_len - NLMSG_HDRLEN;
}
/**
* nlmsg_payload - message payload if the data fits in the len
* @nlh: netlink message header
* @len: struct length
*
* Returns: The netlink message payload/data if the length is sufficient,
* otherwise NULL.
*/
static inline void *nlmsg_payload(const struct nlmsghdr *nlh, size_t len)
{
if (nlh->nlmsg_len < nlmsg_msg_size(len))
return NULL;
return nlmsg_data(nlh);
}
/**
* nlmsg_attrdata - head of attributes data
* @nlh: netlink message header