~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/802/psnap.c

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *      SNAP data link layer. Derived from 802.2
  3  *
  4  *              Alan Cox <alan@lxorguk.ukuu.org.uk>,
  5  *              from the 802.2 layer by Greg Page.
  6  *              Merged in additions from Greg Page's psnap.c.
  7  *
  8  *              This program is free software; you can redistribute it and/or
  9  *              modify it under the terms of the GNU General Public License
 10  *              as published by the Free Software Foundation; either version
 11  *              2 of the License, or (at your option) any later version.
 12  */
 13 
 14 #include <linux/module.h>
 15 #include <linux/netdevice.h>
 16 #include <linux/skbuff.h>
 17 #include <linux/slab.h>
 18 #include <net/datalink.h>
 19 #include <net/llc.h>
 20 #include <net/psnap.h>
 21 #include <linux/mm.h>
 22 #include <linux/in.h>
 23 #include <linux/init.h>
 24 #include <linux/rculist.h>
 25 
 26 static LIST_HEAD(snap_list);
 27 static DEFINE_SPINLOCK(snap_lock);
 28 static struct llc_sap *snap_sap;
 29 
 30 /*
 31  *      Find a snap client by matching the 5 bytes.
 32  */
 33 static struct datalink_proto *find_snap_client(const unsigned char *desc)
 34 {
 35         struct datalink_proto *proto = NULL, *p;
 36 
 37         list_for_each_entry_rcu(p, &snap_list, node) {
 38                 if (!memcmp(p->type, desc, 5)) {
 39                         proto = p;
 40                         break;
 41                 }
 42         }
 43         return proto;
 44 }
 45 
 46 /*
 47  *      A SNAP packet has arrived
 48  */
 49 static int snap_rcv(struct sk_buff *skb, struct net_device *dev,
 50                     struct packet_type *pt, struct net_device *orig_dev)
 51 {
 52         int rc = 1;
 53         struct datalink_proto *proto;
 54         static struct packet_type snap_packet_type = {
 55                 .type = cpu_to_be16(ETH_P_SNAP),
 56         };
 57 
 58         if (unlikely(!pskb_may_pull(skb, 5)))
 59                 goto drop;
 60 
 61         rcu_read_lock();
 62         proto = find_snap_client(skb_transport_header(skb));
 63         if (proto) {
 64                 /* Pass the frame on. */
 65                 skb->transport_header += 5;
 66                 skb_pull_rcsum(skb, 5);
 67                 rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
 68         }
 69         rcu_read_unlock();
 70 
 71         if (unlikely(!proto))
 72                 goto drop;
 73 
 74 out:
 75         return rc;
 76 
 77 drop:
 78         kfree_skb(skb);
 79         goto out;
 80 }
 81 
 82 /*
 83  *      Put a SNAP header on a frame and pass to 802.2
 84  */
 85 static int snap_request(struct datalink_proto *dl,
 86                         struct sk_buff *skb, u8 *dest)
 87 {
 88         memcpy(skb_push(skb, 5), dl->type, 5);
 89         llc_build_and_send_ui_pkt(snap_sap, skb, dest, snap_sap->laddr.lsap);
 90         return 0;
 91 }
 92 
 93 /*
 94  *      Set up the SNAP layer
 95  */
 96 EXPORT_SYMBOL(register_snap_client);
 97 EXPORT_SYMBOL(unregister_snap_client);
 98 
 99 static const char snap_err_msg[] __initconst =
100         KERN_CRIT "SNAP - unable to register with 802.2\n";
101 
102 static int __init snap_init(void)
103 {
104         snap_sap = llc_sap_open(0xAA, snap_rcv);
105         if (!snap_sap) {
106                 printk(snap_err_msg);
107                 return -EBUSY;
108         }
109 
110         return 0;
111 }
112 
113 module_init(snap_init);
114 
115 static void __exit snap_exit(void)
116 {
117         llc_sap_put(snap_sap);
118 }
119 
120 module_exit(snap_exit);
121 
122 
123 /*
124  *      Register SNAP clients. We don't yet use this for IP.
125  */
126 struct datalink_proto *register_snap_client(const unsigned char *desc,
127                                             int (*rcvfunc)(struct sk_buff *,
128                                                            struct net_device *,
129                                                            struct packet_type *,
130                                                            struct net_device *))
131 {
132         struct datalink_proto *proto = NULL;
133 
134         spin_lock_bh(&snap_lock);
135 
136         if (find_snap_client(desc))
137                 goto out;
138 
139         proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
140         if (proto) {
141                 memcpy(proto->type, desc, 5);
142                 proto->rcvfunc          = rcvfunc;
143                 proto->header_length    = 5 + 3; /* snap + 802.2 */
144                 proto->request          = snap_request;
145                 list_add_rcu(&proto->node, &snap_list);
146         }
147 out:
148         spin_unlock_bh(&snap_lock);
149 
150         return proto;
151 }
152 
153 /*
154  *      Unregister SNAP clients. Protocols no longer want to play with us ...
155  */
156 void unregister_snap_client(struct datalink_proto *proto)
157 {
158         spin_lock_bh(&snap_lock);
159         list_del_rcu(&proto->node);
160         spin_unlock_bh(&snap_lock);
161 
162         synchronize_net();
163 
164         kfree(proto);
165 }
166 
167 MODULE_LICENSE("GPL");
168 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp