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[NETLINK]: Add notification message sending interface

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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>
This commit is contained in:
Thomas Graf 2006-08-15 00:31:06 -07:00 committed by David S. Miller
parent 2942e90050
commit d387f6ad10
5 changed files with 42 additions and 7 deletions
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5
include/net/genetlink.h
View File

@ -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);
}
/**

6
include/net/netlink.h
View File

@ -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;

2
net/netlabel/netlabel_user.c
View File

@ -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);
}

34
net/netlink/af_netlink.c
View File

@ -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);

2
net/netlink/genetlink.c
View File

@ -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;
}