From d387f6ad10764fc2174373b4a1cca443adee36e3 Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 15 Aug 2006 00:31:06 -0700 Subject: [PATCH] [NETLINK]: Add notification message sending interface Adds nlmsg_notify() implementing proper notification logic. The message is multicasted to all listeners in the group. The applications the requests orignates from can request a unicast back report in which case said socket will be excluded from the multicast to avoid duplicated notifications. nlmsg_multicast() is extended to take allocation flags to allow notification in atomic contexts. Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/net/genetlink.h | 5 +++-- include/net/netlink.h | 6 ++++-- net/netlabel/netlabel_user.c | 2 +- net/netlink/af_netlink.c | 34 +++++++++++++++++++++++++++++++++- net/netlink/genetlink.c | 2 +- 5 files changed, 42 insertions(+), 7 deletions(-) diff --git a/include/net/genetlink.h b/include/net/genetlink.h index 8c22872642..97d6d3aba9 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -133,11 +133,12 @@ static inline int genlmsg_cancel(struct sk_buff *skb, void *hdr) * @skb: netlink message as socket buffer * @pid: own netlink pid to avoid sending to yourself * @group: multicast group id + * @flags: allocation flags */ static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid, - unsigned int group) + unsigned int group, gfp_t flags) { - return nlmsg_multicast(genl_sock, skb, pid, group); + return nlmsg_multicast(genl_sock, skb, pid, group, flags); } /** diff --git a/include/net/netlink.h b/include/net/netlink.h index 3a5e40b1e0..b154b81d9a 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -43,6 +43,7 @@ * Message Sending: * nlmsg_multicast() multicast message to several groups * nlmsg_unicast() unicast a message to a single socket + * nlmsg_notify() send notification message * * Message Length Calculations: * nlmsg_msg_size(payload) length of message w/o padding @@ -545,15 +546,16 @@ static inline void nlmsg_free(struct sk_buff *skb) * @skb: netlink message as socket buffer * @pid: own netlink pid to avoid sending to yourself * @group: multicast group id + * @flags: allocation flags */ static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb, - u32 pid, unsigned int group) + u32 pid, unsigned int group, gfp_t flags) { int err; NETLINK_CB(skb).dst_group = group; - err = netlink_broadcast(sk, skb, pid, group, GFP_KERNEL); + err = netlink_broadcast(sk, skb, pid, group, flags); if (err > 0) err = 0; diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c index 80022221b0..73cbe66e42 100644 --- a/net/netlabel/netlabel_user.c +++ b/net/netlabel/netlabel_user.c @@ -154,5 +154,5 @@ int netlbl_netlink_snd(struct sk_buff *skb, u32 pid) */ int netlbl_netlink_snd_multicast(struct sk_buff *skb, u32 pid, u32 group) { - return genlmsg_multicast(skb, pid, group); + return genlmsg_multicast(skb, pid, group, GFP_KERNEL); } diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 0f36ddc0b7..a80e4456e2 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1549,6 +1549,38 @@ void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb) skb_pull(skb, msglen); } +/** + * nlmsg_notify - send a notification netlink message + * @sk: netlink socket to use + * @skb: notification message + * @pid: destination netlink pid for reports or 0 + * @group: destination multicast group or 0 + * @report: 1 to report back, 0 to disable + * @flags: allocation flags + */ +int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid, + unsigned int group, int report, gfp_t flags) +{ + int err = 0; + + if (group) { + int exclude_pid = 0; + + if (report) { + atomic_inc(&skb->users); + exclude_pid = pid; + } + + /* errors reported via destination sk->sk_err */ + nlmsg_multicast(sk, skb, exclude_pid, group, flags); + } + + if (report) + err = nlmsg_unicast(sk, skb, pid); + + return err; +} + #ifdef CONFIG_PROC_FS struct nl_seq_iter { int link; @@ -1802,4 +1834,4 @@ EXPORT_SYMBOL(netlink_set_err); EXPORT_SYMBOL(netlink_set_nonroot); EXPORT_SYMBOL(netlink_unicast); EXPORT_SYMBOL(netlink_unregister_notifier); - +EXPORT_SYMBOL(nlmsg_notify); diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 75bb47a898..d32599116c 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -510,7 +510,7 @@ static int genl_ctrl_event(int event, void *data) if (IS_ERR(msg)) return PTR_ERR(msg); - genlmsg_multicast(msg, 0, GENL_ID_CTRL); + genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL); break; } -- 2.39.5