1 files changed, 159 insertions, 0 deletions

diff --git a/net/802/psnap.c b/net/802/psnap.c
new file mode 100644
index 000000000000..1053821ddf93
--- /dev/null
+++ b/net/802/psnap.c
@@ -0,0 +1,159 @@
+/*
+ *      SNAP data link layer. Derived from 802.2
+ *
+ *              Alan Cox <Alan.Cox@linux.org>,
+ *              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 <net/datalink.h>
+#include <net/llc.h>
+#include <net/psnap.h>
+#include <linux/mm.h>
+#include <linux/in.h>
+#include <linux/init.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(unsigned char *desc)
+{
+        struct list_head *entry;
+        struct datalink_proto *proto = NULL, *p;
+
+        list_for_each_rcu(entry, &snap_list) {
+                p = list_entry(entry, struct datalink_proto, 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)
+{
+        int rc = 1;
+        struct datalink_proto *proto;
+        static struct packet_type snap_packet_type = {
+                .type = __constant_htons(ETH_P_SNAP),
+        };
+
+        rcu_read_lock();
+        proto = find_snap_client(skb->h.raw);
+        if (proto) {
+                /* Pass the frame on. */
+                skb->h.raw  += 5;
+                skb_pull(skb, 5);
+                rc = proto->rcvfunc(skb, dev, &snap_packet_type);
+        } else {
+                skb->sk = NULL;
+                kfree_skb(skb);
+                rc = 1;
+        }
+
+        rcu_read_unlock();
+        return rc;
+}
+
+/*
+ *      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 char snap_err_msg[] __initdata =
+        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 0;
+}
+
+module_init(snap_init);
+
+static void __exit snap_exit(void)
+{
+        llc_sap_close(snap_sap);
+}
+
+module_exit(snap_exit);
+
+
+/*
+ *      Register SNAP clients. We don't yet use this for IP.
+ */
+struct datalink_proto *register_snap_client(unsigned char *desc,
+                                            int (*rcvfunc)(struct sk_buff *,
+                                                           struct net_device *,
+                                                           struct packet_type *))
+{
+        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);
+
+        synchronize_net();
+        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");