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
llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff * skb)28 static 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; /* NULL DSAP value */
36 }
37
llc_stat_ev_rx_null_dsap_test_c(struct sk_buff * skb)38 static 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; /* NULL DSAP */
46 }
47
llc_station_ac_send_xid_r(struct sk_buff * skb)48 static 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);
66 out:
67 return rc;
68 free:
69 kfree_skb(nskb);
70 goto out;
71 }
72
llc_station_ac_send_test_r(struct sk_buff * skb)73 static 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 if (skb->mac_len < ETH_HLEN)
81 goto out;
82
83 /* The test request command is type U (llc_len = 3) */
84 data_size = ntohs(eth_hdr(skb)->h_proto) - 3;
85 nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size);
86
87 if (!nskb)
88 goto out;
89 rc = 0;
90 llc_pdu_decode_sa(skb, mac_da);
91 llc_pdu_decode_ssap(skb, &dsap);
92 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
93 llc_pdu_init_as_test_rsp(nskb, skb);
94 rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
95 if (unlikely(rc))
96 goto free;
97 dev_queue_xmit(nskb);
98 out:
99 return rc;
100 free:
101 kfree_skb(nskb);
102 goto out;
103 }
104
105 /**
106 * llc_station_rcv - send received pdu to the station state machine
107 * @skb: received frame.
108 *
109 * Sends data unit to station state machine.
110 */
llc_station_rcv(struct sk_buff * skb)111 static void llc_station_rcv(struct sk_buff *skb)
112 {
113 if (llc_stat_ev_rx_null_dsap_xid_c(skb))
114 llc_station_ac_send_xid_r(skb);
115 else if (llc_stat_ev_rx_null_dsap_test_c(skb))
116 llc_station_ac_send_test_r(skb);
117 kfree_skb(skb);
118 }
119
llc_station_init(void)120 void __init llc_station_init(void)
121 {
122 llc_set_station_handler(llc_station_rcv);
123 }
124
llc_station_exit(void)125 void llc_station_exit(void)
126 {
127 llc_set_station_handler(NULL);
128 }
129