1 files changed, 165 insertions, 0 deletions
diff --git a/runtime/transport/netlink.c b/runtime/transport/netlink.c
new file mode 100644
index 00000000..bfb9d22a
--- /dev/null
+++ b/runtime/transport/netlink.c
@@ -0,0 +1,165 @@
+/*
+ * netlink.c - stp relayfs-related transport functions
+ *
+ * Copyright (C) IBM Corporation, 2005
+ * Copyright (C) Redhat Inc, 2005
+ *
+ * This file is released under the GPL.
+ */
+
+/** @file netlink.c
+ * @brief Systemtap netlink-related transport functions
+ */
+
+/** @addtogroup transport Transport Functions
+ * @{
+ */
+
+#include "netlink.h"
+
+/* the control socket */
+extern struct sock *stp_control;
+
+/* queued packets logged from irq context */
+static struct sk_buff_head delayed_pkts;
+
+/* for netlink sequence numbers */
+static int seq;
+
+/**
+ *	_stp_msg_rcv_skb - dispatch netlink control channel requests
+ */
+static void _stp_msg_rcv_skb(struct sk_buff *skb,
+			     int (*cmd_handler) (int pid, int cmd, void *data))
+{
+	struct nlmsghdr *nlh = NULL;
+	int pid, flags;
+	int nlmsglen, skblen;
+	void *data;
+	
+	skblen = skb->len;
+	
+	if (skblen < sizeof (*nlh))
+		return;	
+
+	nlh = (struct nlmsghdr *)skb->data;
+	nlmsglen = nlh->nlmsg_len;
+	
+	if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
+		return;
+
+	pid = nlh->nlmsg_pid;
+	flags = nlh->nlmsg_flags;
+
+	if (pid <= 0 || !(flags & NLM_F_REQUEST)) {
+		netlink_ack(skb, nlh, -EINVAL);
+		return;
+	}
+
+	if (flags & MSG_TRUNC) {
+		netlink_ack(skb, nlh, -ECOMM);
+		return;
+	}
+	
+	data = NLMSG_DATA(nlh);
+
+	if (cmd_handler(pid, nlh->nlmsg_type, data))
+		netlink_ack(skb, nlh, -EINVAL);		
+	
+	if (flags & NLM_F_ACK)
+		netlink_ack(skb, nlh, 0);
+}
+
+/**
+ *	_stp_msg_rcv - handle netlink control channel requests
+ */
+static void _stp_msg_rcv(struct sock *sk, int len)
+{
+	struct sk_buff *skb;
+	
+	while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
+		_stp_msg_rcv_skb(skb, sk->sk_user_data);
+		kfree_skb(skb);
+	}
+}
+
+/**
+ *	_stp_send_delayed_packets - send delayed netlink packets
+ */
+static void _stp_send_delayed_pkts(unsigned long ignored)
+{
+	struct sk_buff *skb;
+	while ((skb = skb_dequeue(&delayed_pkts)) != NULL) {
+		struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
+		int pid = nlh->nlmsg_pid;
+		netlink_unicast(stp_control, skb, pid, MSG_DONTWAIT);
+	}
+}
+static DECLARE_TASKLET(delayed_pkts_tasklet, _stp_send_delayed_pkts, 0);
+
+/**
+ *	_stp_netlink_send - send data over netlink channel
+ *	@type: message type
+ *	@data: data to send
+ *	@len: length of data
+ *	@pid: pid to send data to
+ */
+int _stp_netlink_send(int type, void *data, int len, int pid)
+{
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	void *d;
+	int size;
+	int err = 0;
+
+	size = NLMSG_SPACE(len);
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	nlh = NLMSG_PUT(skb, pid, seq++, type, size - sizeof(*nlh));
+	nlh->nlmsg_flags = 0;
+	d = NLMSG_DATA(nlh);
+	memcpy(d, data, len);
+
+	if (in_irq()) {
+		skb_queue_tail(&delayed_pkts, skb);
+		tasklet_schedule(&delayed_pkts_tasklet);
+	} else
+		err = netlink_unicast(stp_control, skb, pid, MSG_DONTWAIT);
+
+	return err;
+
+nlmsg_failure:
+	if (skb)
+		kfree_skb(skb);
+	
+	return -1;
+}
+
+/**
+ *	_stp_netlink_open - create netlink socket
+ *	@unit: the netlink 'unit' to create
+ *	@handler: handler function for stp 'commands'
+ */
+struct sock *_stp_netlink_open(int unit,
+			       int (*handler) (int pid, int cmd, void *data))
+{
+	struct sock *nl = netlink_kernel_create(unit, _stp_msg_rcv);
+	if (!nl) {
+		printk("stp-control: couldn't create netlink transport\n");
+		return NULL;
+	}
+	nl->sk_user_data = handler;
+
+	return nl;
+}
+
+/**
+ *	_stp_netlink_close - close netlink socket
+ */
+void _stp_netlink_close (struct sock *nl)
+{
+	BUG_ON(!nl);
+	sock_release(nl->sk_socket);
+}