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 | |
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 | |
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 | |
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, dev: skb->dev, LLC_PDU_TYPE_U, |
53 | data_size: sizeof(struct llc_xid_info)); |
54 | |
55 | if (!nskb) |
56 | goto out; |
57 | llc_pdu_decode_sa(skb, sa: mac_da); |
58 | llc_pdu_decode_ssap(skb, ssap: &dsap); |
59 | llc_pdu_header_init(skb: nskb, LLC_PDU_TYPE_U, ssap: 0, dsap, LLC_PDU_RSP); |
60 | llc_pdu_init_as_xid_rsp(skb: nskb, LLC_XID_NULL_CLASS_2, rx_window: 127); |
61 | rc = llc_mac_hdr_init(skb: nskb, sa: skb->dev->dev_addr, da: mac_da); |
62 | if (unlikely(rc)) |
63 | goto free; |
64 | dev_queue_xmit(skb: nskb); |
65 | out: |
66 | return rc; |
67 | free: |
68 | kfree_skb(skb: nskb); |
69 | goto out; |
70 | } |
71 | |
72 | static int llc_station_ac_send_test_r(struct sk_buff *skb) |
73 | { |
74 | u8 mac_da[ETH_ALEN], dsap; |
75 | int rc = 1; |
76 | u32 data_size; |
77 | struct sk_buff *nskb; |
78 | |
79 | /* The test request command is type U (llc_len = 3) */ |
80 | data_size = ntohs(eth_hdr(skb)->h_proto) - 3; |
81 | nskb = llc_alloc_frame(NULL, dev: skb->dev, LLC_PDU_TYPE_U, data_size); |
82 | |
83 | if (!nskb) |
84 | goto out; |
85 | llc_pdu_decode_sa(skb, sa: mac_da); |
86 | llc_pdu_decode_ssap(skb, ssap: &dsap); |
87 | llc_pdu_header_init(skb: nskb, LLC_PDU_TYPE_U, ssap: 0, dsap, LLC_PDU_RSP); |
88 | llc_pdu_init_as_test_rsp(skb: nskb, ev_skb: skb); |
89 | rc = llc_mac_hdr_init(skb: nskb, sa: skb->dev->dev_addr, da: mac_da); |
90 | if (unlikely(rc)) |
91 | goto free; |
92 | dev_queue_xmit(skb: nskb); |
93 | out: |
94 | return rc; |
95 | free: |
96 | kfree_skb(skb: nskb); |
97 | goto out; |
98 | } |
99 | |
100 | /** |
101 | * llc_station_rcv - send received pdu to the station state machine |
102 | * @skb: received frame. |
103 | * |
104 | * Sends data unit to station state machine. |
105 | */ |
106 | static void llc_station_rcv(struct sk_buff *skb) |
107 | { |
108 | if (llc_stat_ev_rx_null_dsap_xid_c(skb)) |
109 | llc_station_ac_send_xid_r(skb); |
110 | else if (llc_stat_ev_rx_null_dsap_test_c(skb)) |
111 | llc_station_ac_send_test_r(skb); |
112 | kfree_skb(skb); |
113 | } |
114 | |
115 | void __init llc_station_init(void) |
116 | { |
117 | llc_set_station_handler(handler: llc_station_rcv); |
118 | } |
119 | |
120 | void llc_station_exit(void) |
121 | { |
122 | llc_set_station_handler(NULL); |
123 | } |
124 | |