xref: /openbmc/linux/net/llc/llc_output.c (revision 87c2ce3b)
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/if_tr.h>
18 #include <linux/netdevice.h>
19 #include <linux/trdevice.h>
20 #include <linux/skbuff.h>
21 #include <net/llc.h>
22 #include <net/llc_pdu.h>
23 
24 /**
25  *	llc_mac_hdr_init - fills MAC header fields
26  *	@skb: Address of the frame to initialize its MAC header
27  *	@sa: The MAC source address
28  *	@da: The MAC destination address
29  *
30  *	Fills MAC header fields, depending on MAC type. Returns 0, If MAC type
31  *	is a valid type and initialization completes correctly 1, otherwise.
32  */
33 int llc_mac_hdr_init(struct sk_buff *skb, unsigned char *sa, unsigned char *da)
34 {
35 	int rc = 0;
36 
37 	switch (skb->dev->type) {
38 #ifdef CONFIG_TR
39 	case ARPHRD_IEEE802_TR: {
40 		struct net_device *dev = skb->dev;
41 		struct trh_hdr *trh;
42 
43 		skb->mac.raw = skb_push(skb, sizeof(*trh));
44 		trh = tr_hdr(skb);
45 		trh->ac = AC;
46 		trh->fc = LLC_FRAME;
47 		if (sa)
48 			memcpy(trh->saddr, sa, dev->addr_len);
49 		else
50 			memset(trh->saddr, 0, dev->addr_len);
51 		if (da) {
52 			memcpy(trh->daddr, da, dev->addr_len);
53 			tr_source_route(skb, trh, dev);
54 			skb->mac.raw = skb->data;
55 		}
56 		break;
57 	}
58 #endif
59 	case ARPHRD_ETHER:
60 	case ARPHRD_LOOPBACK: {
61 		unsigned short len = skb->len;
62 		struct ethhdr *eth;
63 
64 		skb->mac.raw = skb_push(skb, sizeof(*eth));
65 		eth = eth_hdr(skb);
66 		eth->h_proto = htons(len);
67 		memcpy(eth->h_dest, da, ETH_ALEN);
68 		memcpy(eth->h_source, sa, ETH_ALEN);
69 		break;
70 	}
71 	default:
72 		printk(KERN_WARNING "device type not supported: %d\n",
73 		       skb->dev->type);
74 		rc = -EINVAL;
75 	}
76 	return rc;
77 }
78 
79 /**
80  *	llc_build_and_send_ui_pkt - unitdata request interface for upper layers
81  *	@sap: sap to use
82  *	@skb: packet to send
83  *	@dmac: destination mac address
84  *	@dsap: destination sap
85  *
86  *	Upper layers calls this function when upper layer wants to send data
87  *	using connection-less mode communication (UI pdu).
88  *
89  *	Accept data frame from network layer to be sent using connection-
90  *	less mode communication; timeout/retries handled by network layer;
91  *	package primitive as an event and send to SAP event handler
92  */
93 int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
94 			      unsigned char *dmac, unsigned char dsap)
95 {
96 	int rc;
97 	llc_pdu_header_init(skb, LLC_PDU_TYPE_U, sap->laddr.lsap,
98 			    dsap, LLC_PDU_CMD);
99 	llc_pdu_init_as_ui_cmd(skb);
100 	rc = llc_mac_hdr_init(skb, skb->dev->dev_addr, dmac);
101 	if (likely(!rc))
102 		rc = dev_queue_xmit(skb);
103 	return rc;
104 }
105 
106 EXPORT_SYMBOL(llc_mac_hdr_init);
107 EXPORT_SYMBOL(llc_build_and_send_ui_pkt);
108