From 95d06e92a401928fe46fda7616e460f39cb7211b Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Mon, 14 Apr 2025 06:24:07 -0700 Subject: [PATCH] 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 Signed-off-by: Breno Leitao Reviewed-by: Jakub Kicinski Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250414-nlmsg-v2-1-3d90cb42c6af@debian.org Signed-off-by: Jakub Kicinski --- include/net/netlink.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/net/netlink.h b/include/net/netlink.h index 29e0db9403820..82e07e272290a 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -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 -- 2.39.5