From d387f6ad10764fc2174373b4a1cca443adee36e3 Mon Sep 17 00:00:00 2001
From: Thomas Graf <tgraf@suug.ch>
Date: Tue, 15 Aug 2006 00:31:06 -0700
Subject: [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 <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/netlabel/netlabel_user.c | 2 +-
net/netlink/af_netlink.c | 34 +++++++++++++++++++++++++++++++++-
net/netlink/genetlink.c | 2 +-
3 files changed, 35 insertions(+), 3 deletions(-)
(limited to 'net')
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 8002222..73cbe66 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 0f36ddc..a80e445 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 75bb47a..d325991 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;
}
--
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