From bb9b18fb55b03477fe5bdd3e97245d6d4d3dee4f Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Sat, 30 Nov 2013 13:21:30 +0100 Subject: [PATCH] genl: Add genlmsg_new_unicast() for unicast message allocation Allocates a new sk_buff large enough to cover the specified payload plus required Netlink headers. Will check receiving socket for memory mapped i/o capability and use it if enabled. Will fall back to non-mapped skb if message size exceeds the frame size of the ring. Signed-of-by: Thomas Graf Reviewed-by: Daniel Borkmann Signed-off-by: Jesse Gross --- include/net/genetlink.h | 4 ++++ net/netlink/genetlink.c | 21 +++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/include/net/genetlink.h b/include/net/genetlink.h index 1b177ed..93695f0 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -73,6 +73,7 @@ struct genl_family { * @attrs: netlink attributes * @_net: network namespace * @user_ptr: user pointers + * @dst_sk: destination socket */ struct genl_info { u32 snd_seq; @@ -85,6 +86,7 @@ struct genl_info { struct net * _net; #endif void * user_ptr[2]; + struct sock * dst_sk; }; static inline struct net *genl_info_net(struct genl_info *info) @@ -177,6 +179,8 @@ void genl_notify(struct genl_family *family, struct sk_buff *skb, struct net *net, u32 portid, u32 group, struct nlmsghdr *nlh, gfp_t flags); +struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, + gfp_t flags); void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, struct genl_family *family, int flags, u8 cmd); diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 4518a57..85bf42e 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -454,6 +454,26 @@ int genl_unregister_family(struct genl_family *family) EXPORT_SYMBOL(genl_unregister_family); /** + * genlmsg_new_unicast - Allocate generic netlink message for unicast + * @payload: size of the message payload + * @info: information on destination + * @flags: the type of memory to allocate + * + * Allocates a new sk_buff large enough to cover the specified payload + * plus required Netlink headers. Will check receiving socket for + * memory mapped i/o capability and use it if enabled. Will fall back + * to non-mapped skb if message size exceeds the frame size of the ring. + */ +struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, + gfp_t flags) +{ + size_t len = nlmsg_total_size(genlmsg_total_size(payload)); + + return netlink_alloc_skb(info->dst_sk, len, info->snd_portid, flags); +} +EXPORT_SYMBOL_GPL(genlmsg_new_unicast); + +/** * genlmsg_put - Add generic netlink header to netlink message * @skb: socket buffer holding the message * @portid: netlink portid the message is addressed to @@ -593,6 +613,7 @@ static int genl_family_rcv_msg(struct genl_family *family, info.genlhdr = nlmsg_data(nlh); info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; info.attrs = attrbuf; + info.dst_sk = skb->sk; genl_info_net_set(&info, net); memset(&info.user_ptr, 0, sizeof(info.user_ptr)); -- 2.7.4