Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / net / 802 / psnap.c

diff --git a/kernel/net/802/psnap.c b/kernel/net/802/psnap.c
new file mode 100644 (file)
index 0000000..db6baf7
--- /dev/null
+++ b/kernel/net/802/psnap.c
@@ -0,0 +1,167 @@
+/*
+ *     SNAP data link layer. Derived from 802.2
+ *
+ *             Alan Cox <alan@lxorguk.ukuu.org.uk>,
+ *             from the 802.2 layer by Greg Page.
+ *             Merged in additions from Greg Page's psnap.c.
+ *
+ *             This program is free software; you can redistribute it and/or
+ *             modify it under the terms of the GNU General Public License
+ *             as published by the Free Software Foundation; either version
+ *             2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/datalink.h>
+#include <net/llc.h>
+#include <net/psnap.h>
+#include <linux/mm.h>
+#include <linux/in.h>
+#include <linux/init.h>
+#include <linux/rculist.h>
+
+static LIST_HEAD(snap_list);
+static DEFINE_SPINLOCK(snap_lock);
+static struct llc_sap *snap_sap;
+
+/*
+ *     Find a snap client by matching the 5 bytes.
+ */
+static struct datalink_proto *find_snap_client(const unsigned char *desc)
+{
+       struct datalink_proto *proto = NULL, *p;
+
+       list_for_each_entry_rcu(p, &snap_list, node) {
+               if (!memcmp(p->type, desc, 5)) {
+                       proto = p;
+                       break;
+               }
+       }
+       return proto;
+}
+
+/*
+ *     A SNAP packet has arrived
+ */
+static int snap_rcv(struct sk_buff *skb, struct net_device *dev,
+                   struct packet_type *pt, struct net_device *orig_dev)
+{
+       int rc = 1;
+       struct datalink_proto *proto;
+       static struct packet_type snap_packet_type = {
+               .type = cpu_to_be16(ETH_P_SNAP),
+       };
+
+       if (unlikely(!pskb_may_pull(skb, 5)))
+               goto drop;
+
+       rcu_read_lock();
+       proto = find_snap_client(skb_transport_header(skb));
+       if (proto) {
+               /* Pass the frame on. */
+               skb->transport_header += 5;
+               skb_pull_rcsum(skb, 5);
+               rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
+       }
+       rcu_read_unlock();
+
+       if (unlikely(!proto))
+               goto drop;
+
+out:
+       return rc;
+
+drop:
+       kfree_skb(skb);
+       goto out;
+}
+
+/*
+ *     Put a SNAP header on a frame and pass to 802.2
+ */
+static int snap_request(struct datalink_proto *dl,
+                       struct sk_buff *skb, u8 *dest)
+{
+       memcpy(skb_push(skb, 5), dl->type, 5);
+       llc_build_and_send_ui_pkt(snap_sap, skb, dest, snap_sap->laddr.lsap);
+       return 0;
+}
+
+/*
+ *     Set up the SNAP layer
+ */
+EXPORT_SYMBOL(register_snap_client);
+EXPORT_SYMBOL(unregister_snap_client);
+
+static const char snap_err_msg[] __initconst =
+       KERN_CRIT "SNAP - unable to register with 802.2\n";
+
+static int __init snap_init(void)
+{
+       snap_sap = llc_sap_open(0xAA, snap_rcv);
+       if (!snap_sap) {
+               printk(snap_err_msg);
+               return -EBUSY;
+       }
+
+       return 0;
+}
+
+module_init(snap_init);
+
+static void __exit snap_exit(void)
+{
+       llc_sap_put(snap_sap);
+}
+
+module_exit(snap_exit);
+
+
+/*
+ *     Register SNAP clients. We don't yet use this for IP.
+ */
+struct datalink_proto *register_snap_client(const unsigned char *desc,
+                                           int (*rcvfunc)(struct sk_buff *,
+                                                          struct net_device *,
+                                                          struct packet_type *,
+                                                          struct net_device *))
+{
+       struct datalink_proto *proto = NULL;
+
+       spin_lock_bh(&snap_lock);
+
+       if (find_snap_client(desc))
+               goto out;
+
+       proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
+       if (proto) {
+               memcpy(proto->type, desc, 5);
+               proto->rcvfunc          = rcvfunc;
+               proto->header_length    = 5 + 3; /* snap + 802.2 */
+               proto->request          = snap_request;
+               list_add_rcu(&proto->node, &snap_list);
+       }
+out:
+       spin_unlock_bh(&snap_lock);
+
+       return proto;
+}
+
+/*
+ *     Unregister SNAP clients. Protocols no longer want to play with us ...
+ */
+void unregister_snap_client(struct datalink_proto *proto)
+{
+       spin_lock_bh(&snap_lock);
+       list_del_rcu(&proto->node);
+       spin_unlock_bh(&snap_lock);
+
+       synchronize_net();
+
+       kfree(proto);
+}
+
+MODULE_LICENSE("GPL");