^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * SNAP data link layer. Derived from 802.2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Alan Cox <alan@lxorguk.ukuu.org.uk>,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * from the 802.2 layer by Greg Page.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Merged in additions from Greg Page's psnap.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/netdevice.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/skbuff.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <net/datalink.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <net/llc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <net/psnap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <linux/in.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include <linux/rculist.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) static LIST_HEAD(snap_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) static DEFINE_SPINLOCK(snap_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) static struct llc_sap *snap_sap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * Find a snap client by matching the 5 bytes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) static struct datalink_proto *find_snap_client(const unsigned char *desc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) struct datalink_proto *proto = NULL, *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) list_for_each_entry_rcu(p, &snap_list, node, lockdep_is_held(&snap_lock)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) if (!memcmp(p->type, desc, 5)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) proto = p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) return proto;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * A SNAP packet has arrived
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) static int snap_rcv(struct sk_buff *skb, struct net_device *dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) struct packet_type *pt, struct net_device *orig_dev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) int rc = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) struct datalink_proto *proto;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) static struct packet_type snap_packet_type = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) .type = cpu_to_be16(ETH_P_SNAP),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) if (unlikely(!pskb_may_pull(skb, 5)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) goto drop;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) proto = find_snap_client(skb_transport_header(skb));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) if (proto) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) /* Pass the frame on. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) skb->transport_header += 5;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) skb_pull_rcsum(skb, 5);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) if (unlikely(!proto))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) goto drop;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) drop:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) kfree_skb(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) * Put a SNAP header on a frame and pass to 802.2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) static int snap_request(struct datalink_proto *dl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) struct sk_buff *skb, u8 *dest)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) memcpy(skb_push(skb, 5), dl->type, 5);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) llc_build_and_send_ui_pkt(snap_sap, skb, dest, snap_sap->laddr.lsap);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * Set up the SNAP layer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) EXPORT_SYMBOL(register_snap_client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) EXPORT_SYMBOL(unregister_snap_client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) static const char snap_err_msg[] __initconst =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) KERN_CRIT "SNAP - unable to register with 802.2\n";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) static int __init snap_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) snap_sap = llc_sap_open(0xAA, snap_rcv);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) if (!snap_sap) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) printk(snap_err_msg);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) module_init(snap_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) static void __exit snap_exit(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) llc_sap_put(snap_sap);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) module_exit(snap_exit);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) * Register SNAP clients. We don't yet use this for IP.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) struct datalink_proto *register_snap_client(const unsigned char *desc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) int (*rcvfunc)(struct sk_buff *,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) struct net_device *,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) struct packet_type *,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) struct net_device *))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) struct datalink_proto *proto = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) spin_lock_bh(&snap_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) if (find_snap_client(desc))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) if (proto) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) memcpy(proto->type, desc, 5);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) proto->rcvfunc = rcvfunc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) proto->header_length = 5 + 3; /* snap + 802.2 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) proto->request = snap_request;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) list_add_rcu(&proto->node, &snap_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) spin_unlock_bh(&snap_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) return proto;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) * Unregister SNAP clients. Protocols no longer want to play with us ...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) void unregister_snap_client(struct datalink_proto *proto)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) spin_lock_bh(&snap_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) list_del_rcu(&proto->node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) spin_unlock_bh(&snap_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) synchronize_net();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) kfree(proto);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) MODULE_LICENSE("GPL");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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