event.c

iscsi企业级target.很好用

/*
 * Event notification code.
 * (C) 2005 FUJITA Tomonori <[e-mail]>
 * This code is licenced under the GPL.
 *
 * Some functions are based on audit code.
 */

#include <net/tcp.h>
#include "iet_u.h"
#include "iscsi_dbg.h"

static struct sock *nl;
static u32 ietd_pid;

static int event_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	u32 uid, pid, seq;
	char *data;

	pid  = NETLINK_CREDS(skb)->pid;
	uid  = NETLINK_CREDS(skb)->uid;
	seq  = nlh->nlmsg_seq;
	data = NLMSG_DATA(nlh);

	ietd_pid = pid;

	return 0;
}

static int event_recv_skb(struct sk_buff *skb)
{
	int err;
	struct nlmsghdr	*nlh;
	u32 rlen;

	while (skb->len >= NLMSG_SPACE(0)) {
		nlh = (struct nlmsghdr *)skb->data;
		if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
			return 0;
		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
		if (rlen > skb->len)
			rlen = skb->len;
		if ((err = event_recv_msg(skb, nlh))) {
			netlink_ack(skb, nlh, -err);
		} else if (nlh->nlmsg_flags & NLM_F_ACK)
			netlink_ack(skb, nlh, 0);
		skb_pull(skb, rlen);
	}
	return 0;
}

static void event_recv(struct sock *sk, int length)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
		if (event_recv_skb(skb) && skb->len)
			skb_queue_head(&sk->sk_receive_queue, skb);
		else
			kfree_skb(skb);
	}
}

static int notify(void *data, int len, int gfp_mask)
{
	struct sk_buff *skb;
	struct nlmsghdr *nlh;
	static u32 seq = 0;

	if (!(skb = alloc_skb(NLMSG_SPACE(len), gfp_mask)))
		return -ENOMEM;

	nlh = __nlmsg_put(skb, ietd_pid, seq++, NLMSG_DONE, len - sizeof(*nlh), 0);

	memcpy(NLMSG_DATA(nlh), data, len);

	return netlink_unicast(nl, skb, ietd_pid, 0);
}

int event_send(u32 tid, u64 sid, u32 cid, u32 state, int atomic)
{
	int err;
	struct iet_event event;

	event.tid = tid;
	event.sid = sid;
	event.cid = cid;
	event.state = state;

	err = notify(&event, NLMSG_SPACE(sizeof(struct iet_event)), 0);

	return err;
}

int event_init(void)
{
	if (!(nl = netlink_kernel_create(NETLINK_IET, event_recv)))
		return -ENOMEM;
	else
		return 0;
}

void event_exit(void)
{
	if (nl)
		sock_release(nl->sk_socket);
}