From 5aa51d9f889ca61201044b28677eb60236b0d746 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 14 Aug 2023 14:47:20 -0700 Subject: [PATCH] genetlink: add genlmsg_iput() API Add some APIs and helpers required for convenient construction of replies and notifications based on struct genl_info. Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20230814214723.2924989-8-kuba@kernel.org Signed-off-by: Jakub Kicinski --- include/net/genetlink.h | 54 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/include/net/genetlink.h b/include/net/genetlink.h index 6b858c4..e18a4c0 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -113,7 +113,7 @@ struct genl_info { struct netlink_ext_ack *extack; }; -static inline struct net *genl_info_net(struct genl_info *info) +static inline struct net *genl_info_net(const struct genl_info *info) { return read_pnet(&info->_net); } @@ -270,6 +270,32 @@ genl_info_dump(struct netlink_callback *cb) return &genl_dumpit_info(cb)->info; } +/** + * genl_info_init_ntf() - initialize genl_info for notifications + * @info: genl_info struct to set up + * @family: pointer to the genetlink family + * @cmd: command to be used in the notification + * + * Initialize a locally declared struct genl_info to pass to various APIs. + * Intended to be used when creating notifications. + */ +static inline void +genl_info_init_ntf(struct genl_info *info, const struct genl_family *family, + u8 cmd) +{ + struct genlmsghdr *hdr = (void *) &info->user_ptr[0]; + + memset(info, 0, sizeof(*info)); + info->family = family; + info->genlhdr = hdr; + hdr->cmd = cmd; +} + +static inline bool genl_info_is_ntf(const struct genl_info *info) +{ + return !info->nlhdr; +} + int genl_register_family(struct genl_family *family); int genl_unregister_family(const struct genl_family *family); void genl_notify(const struct genl_family *family, struct sk_buff *skb, @@ -278,6 +304,32 @@ void genl_notify(const struct genl_family *family, struct sk_buff *skb, void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, const struct genl_family *family, int flags, u8 cmd); +static inline void * +__genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags) +{ + return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family, + flags, info->genlhdr->cmd); +} + +/** + * genlmsg_iput - start genetlink message based on genl_info + * @skb: skb in which message header will be placed + * @info: genl_info as provided to do/dump handlers + * + * Convenience wrapper which starts a genetlink message based on + * information in user request. @info should be either the struct passed + * by genetlink core to do/dump handlers (when constructing replies to + * such requests) or a struct initialized by genl_info_init_ntf() + * when constructing notifications. + * + * Returns pointer to new genetlink header. + */ +static inline void * +genlmsg_iput(struct sk_buff *skb, const struct genl_info *info) +{ + return __genlmsg_iput(skb, info, 0); +} + /** * genlmsg_nlhdr - Obtain netlink header from user specified header * @user_hdr: user header as returned from genlmsg_put() -- 2.7.4