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| 1 | +// SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | +/* |
| 3 | + * NET3: Support for 802.2 demultiplexing off Ethernet |
| 4 | + * |
| 5 | + * Demultiplex 802.2 encoded protocols. We match the entry by the |
| 6 | + * SSAP/DSAP pair and then deliver to the registered datalink that |
| 7 | + * matches. The control byte is ignored and handling of such items |
| 8 | + * is up to the routine passed the frame. |
| 9 | + * |
| 10 | + * Unlike the 802.3 datalink we have a list of 802.2 entries as |
| 11 | + * there are multiple protocols to demux. The list is currently |
| 12 | + * short (3 or 4 entries at most). The current demux assumes this. |
| 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 <linux/mm.h> |
| 20 | +#include <linux/in.h> |
| 21 | +#include <linux/init.h> |
| 22 | +#include <net/llc.h> |
| 23 | +#include <net/p8022.h> |
| 24 | + |
| 25 | +static int p8022_request(struct datalink_proto *dl, struct sk_buff *skb, |
| 26 | + const unsigned char *dest) |
| 27 | +{ |
| 28 | + llc_build_and_send_ui_pkt(dl->sap, skb, dest, dl->sap->laddr.lsap); |
| 29 | + return 0; |
| 30 | +} |
| 31 | + |
| 32 | +struct datalink_proto *register_8022_client(unsigned char type, |
| 33 | + int (*func)(struct sk_buff *skb, |
| 34 | + struct net_device *dev, |
| 35 | + struct packet_type *pt, |
| 36 | + struct net_device *orig_dev)) |
| 37 | +{ |
| 38 | + struct datalink_proto *proto; |
| 39 | + |
| 40 | + proto = kmalloc(sizeof(*proto), GFP_ATOMIC); |
| 41 | + if (proto) { |
| 42 | + proto->type[0] = type; |
| 43 | + proto->header_length = 3; |
| 44 | + proto->request = p8022_request; |
| 45 | + proto->sap = llc_sap_open(type, func); |
| 46 | + if (!proto->sap) { |
| 47 | + kfree(proto); |
| 48 | + proto = NULL; |
| 49 | + } |
| 50 | + } |
| 51 | + return proto; |
| 52 | +} |
| 53 | + |
| 54 | +void unregister_8022_client(struct datalink_proto *proto) |
| 55 | +{ |
| 56 | + llc_sap_put(proto->sap); |
| 57 | + kfree(proto); |
| 58 | +} |
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