1/*
2 * llc_station.c - station component of LLC
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 as published by the Free Software Foundation.
9 * This program is distributed without any warranty or implied warranty
10 * of merchantability or fitness for a particular purpose.
11 *
12 * See the GNU General Public License for more details.
13 */
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <net/llc.h>
18#include <net/llc_sap.h>
19#include <net/llc_conn.h>
20#include <net/llc_c_ac.h>
21#include <net/llc_s_ac.h>
22#include <net/llc_c_ev.h>
23#include <net/llc_c_st.h>
24#include <net/llc_s_ev.h>
25#include <net/llc_s_st.h>
26#include <net/llc_pdu.h>
27
28static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
29{
30	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
31
32	return LLC_PDU_IS_CMD(pdu) &&			/* command PDU */
33	       LLC_PDU_TYPE_IS_U(pdu) &&		/* U type PDU */
34	       LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
35	       !pdu->dsap ? 0 : 1;			/* NULL DSAP value */
36}
37
38static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
39{
40	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
41
42	return LLC_PDU_IS_CMD(pdu) &&			/* command PDU */
43	       LLC_PDU_TYPE_IS_U(pdu) &&		/* U type PDU */
44	       LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
45	       !pdu->dsap ? 0 : 1;			/* NULL DSAP */
46}
47
48static int llc_station_ac_send_xid_r(struct sk_buff *skb)
49{
50	u8 mac_da[ETH_ALEN], dsap;
51	int rc = 1;
52	struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U,
53					       sizeof(struct llc_xid_info));
54
55	if (!nskb)
56		goto out;
57	rc = 0;
58	llc_pdu_decode_sa(skb, mac_da);
59	llc_pdu_decode_ssap(skb, &dsap);
60	llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
61	llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
62	rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
63	if (unlikely(rc))
64		goto free;
65	dev_queue_xmit(nskb);
66out:
67	return rc;
68free:
69	kfree_skb(nskb);
70	goto out;
71}
72
73static int llc_station_ac_send_test_r(struct sk_buff *skb)
74{
75	u8 mac_da[ETH_ALEN], dsap;
76	int rc = 1;
77	u32 data_size;
78	struct sk_buff *nskb;
79
80	/* The test request command is type U (llc_len = 3) */
81	data_size = ntohs(eth_hdr(skb)->h_proto) - 3;
82	nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size);
83
84	if (!nskb)
85		goto out;
86	rc = 0;
87	llc_pdu_decode_sa(skb, mac_da);
88	llc_pdu_decode_ssap(skb, &dsap);
89	llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
90	llc_pdu_init_as_test_rsp(nskb, skb);
91	rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
92	if (unlikely(rc))
93		goto free;
94	dev_queue_xmit(nskb);
95out:
96	return rc;
97free:
98	kfree_skb(nskb);
99	goto out;
100}
101
102/**
103 *	llc_station_rcv - send received pdu to the station state machine
104 *	@skb: received frame.
105 *
106 *	Sends data unit to station state machine.
107 */
108static void llc_station_rcv(struct sk_buff *skb)
109{
110	if (llc_stat_ev_rx_null_dsap_xid_c(skb))
111		llc_station_ac_send_xid_r(skb);
112	else if (llc_stat_ev_rx_null_dsap_test_c(skb))
113		llc_station_ac_send_test_r(skb);
114	kfree_skb(skb);
115}
116
117void __init llc_station_init(void)
118{
119	llc_set_station_handler(llc_station_rcv);
120}
121
122void llc_station_exit(void)
123{
124	llc_set_station_handler(NULL);
125}
126