llc_output.c revision 211ed865108e24697b44bee5daac502ee6bdd4a4 
1/*
2 * llc_output.c - LLC minimal output path
3 *
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * This program can be redistributed or modified under the terms of the
8 * GNU General Public License version 2 as published by the Free Software
9 * Foundation.
10 * This program is distributed without any warranty or implied warranty
11 * of merchantability or fitness for a particular purpose.
12 *
13 * See the GNU General Public License version 2 for more details.
14 */
15
16#include <linux/if_arp.h>
17#include <linux/netdevice.h>
18#include <linux/skbuff.h>
19#include <linux/export.h>
20#include <net/llc.h>
21#include <net/llc_pdu.h>
22
23/**
24 *	llc_mac_hdr_init - fills MAC header fields
25 *	@skb: Address of the frame to initialize its MAC header
26 *	@sa: The MAC source address
27 *	@da: The MAC destination address
28 *
29 *	Fills MAC header fields, depending on MAC type. Returns 0, If MAC type
30 *	is a valid type and initialization completes correctly 1, otherwise.
31 */
32int llc_mac_hdr_init(struct sk_buff *skb,
33		     const unsigned char *sa, const unsigned char *da)
34{
35	int rc = -EINVAL;
36
37	switch (skb->dev->type) {
38	case ARPHRD_ETHER:
39	case ARPHRD_LOOPBACK:
40		rc = dev_hard_header(skb, skb->dev, ETH_P_802_2, da, sa,
41				     skb->len);
42		if (rc > 0)
43			rc = 0;
44		break;
45	default:
46		WARN(1, "device type not supported: %d\n", skb->dev->type);
47	}
48	return rc;
49}
50
51/**
52 *	llc_build_and_send_ui_pkt - unitdata request interface for upper layers
53 *	@sap: sap to use
54 *	@skb: packet to send
55 *	@dmac: destination mac address
56 *	@dsap: destination sap
57 *
58 *	Upper layers calls this function when upper layer wants to send data
59 *	using connection-less mode communication (UI pdu).
60 *
61 *	Accept data frame from network layer to be sent using connection-
62 *	less mode communication; timeout/retries handled by network layer;
63 *	package primitive as an event and send to SAP event handler
64 */
65int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
66			      unsigned char *dmac, unsigned char dsap)
67{
68	int rc;
69	llc_pdu_header_init(skb, LLC_PDU_TYPE_U, sap->laddr.lsap,
70			    dsap, LLC_PDU_CMD);
71	llc_pdu_init_as_ui_cmd(skb);
72	rc = llc_mac_hdr_init(skb, skb->dev->dev_addr, dmac);
73	if (likely(!rc))
74		rc = dev_queue_xmit(skb);
75	return rc;
76}
77
78EXPORT_SYMBOL(llc_mac_hdr_init);
79EXPORT_SYMBOL(llc_build_and_send_ui_pkt);
80