xref: /openbmc/linux/net/llc/llc_output.c (revision 82e6fdd6)
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  */
32 int 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 		break;
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  */
65 int 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 
78 EXPORT_SYMBOL(llc_mac_hdr_init);
79 EXPORT_SYMBOL(llc_build_and_send_ui_pkt);
80