1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
/*
* llc_station.c - station component of LLC
*
* Copyright (c) 1997 by Procom Technology, Inc.
* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <net/llc.h>
#include <net/llc_sap.h>
#include <net/llc_conn.h>
#include <net/llc_c_ac.h>
#include <net/llc_s_ac.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_st.h>
#include <net/llc_s_ev.h>
#include <net/llc_s_st.h>
#include <net/llc_pdu.h>
typedef int (*llc_station_ev_t)(struct sk_buff *skb);
typedef int (*llc_station_action_t)(struct sk_buff *skb);
/* Station component state table structure */
struct llc_station_state_trans {
llc_station_ev_t ev;
llc_station_action_t *ev_actions;
};
static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return LLC_PDU_IS_CMD(pdu) && /* command PDU */
LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
!pdu->dsap ? 0 : 1; /* NULL DSAP value */
}
static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return LLC_PDU_IS_CMD(pdu) && /* command PDU */
LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
!pdu->dsap ? 0 : 1; /* NULL DSAP */
}
static int llc_station_ac_send_xid_r(struct sk_buff *skb)
{
u8 mac_da[ETH_ALEN], dsap;
int rc = 1;
struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U,
sizeof(struct llc_xid_info));
if (!nskb)
goto out;
rc = 0;
llc_pdu_decode_sa(skb, mac_da);
llc_pdu_decode_ssap(skb, &dsap);
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
if (unlikely(rc))
goto free;
dev_queue_xmit(nskb);
out:
return rc;
free:
kfree_skb(nskb);
goto out;
}
static int llc_station_ac_send_test_r(struct sk_buff *skb)
{
u8 mac_da[ETH_ALEN], dsap;
int rc = 1;
u32 data_size;
struct sk_buff *nskb;
/* The test request command is type U (llc_len = 3) */
data_size = ntohs(eth_hdr(skb)->h_proto) - 3;
nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size);
if (!nskb)
goto out;
rc = 0;
llc_pdu_decode_sa(skb, mac_da);
llc_pdu_decode_ssap(skb, &dsap);
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
llc_pdu_init_as_test_rsp(nskb, skb);
rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
if (unlikely(rc))
goto free;
dev_queue_xmit(nskb);
out:
return rc;
free:
kfree_skb(nskb);
goto out;
}
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
static llc_station_action_t llc_stat_up_state_actions_2[] = {
[0] = llc_station_ac_send_xid_r,
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
.ev = llc_stat_ev_rx_null_dsap_xid_c,
.ev_actions = llc_stat_up_state_actions_2,
};
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
static llc_station_action_t llc_stat_up_state_actions_3[] = {
[0] = llc_station_ac_send_test_r,
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
.ev = llc_stat_ev_rx_null_dsap_test_c,
.ev_actions = llc_stat_up_state_actions_3,
};
/* array of pointers; one to each transition */
static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
&llc_stat_up_state_trans_2,
&llc_stat_up_state_trans_3,
NULL,
};
/**
* llc_exec_station_trans_actions - executes actions for transition
* @trans: Address of the transition
* @skb: Address of the event that caused the transition
*
* Executes actions of a transition of the station state machine. Returns
* 0 if all actions complete successfully, nonzero otherwise.
*/
static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
struct sk_buff *skb)
{
u16 rc = 0;
llc_station_action_t *next_action = trans->ev_actions;
for (; next_action && *next_action; next_action++)
if ((*next_action)(skb))
rc = 1;
return rc;
}
/**
* llc_find_station_trans - finds transition for this event
* @skb: Address of the event
*
* Search thru events of the current state of the station until list
* exhausted or it's obvious that the event is not valid for the current
* state. Returns the address of the transition if cound, %NULL otherwise.
*/
static struct llc_station_state_trans *
llc_find_station_trans(struct sk_buff *skb)
{
int i = 0;
struct llc_station_state_trans *rc = NULL;
struct llc_station_state_trans **next_trans;
for (next_trans = llc_stat_up_state_trans; next_trans[i]; i++)
if (!next_trans[i]->ev(skb)) {
rc = next_trans[i];
break;
}
return rc;
}
/**
* llc_station_rcv - send received pdu to the station state machine
* @skb: received frame.
*
* Sends data unit to station state machine.
*/
static void llc_station_rcv(struct sk_buff *skb)
{
struct llc_station_state_trans *trans;
trans = llc_find_station_trans(skb);
if (trans)
llc_exec_station_trans_actions(trans, skb);
kfree_skb(skb);
}
void __init llc_station_init(void)
{
llc_set_station_handler(llc_station_rcv);
}
void llc_station_exit(void)
{
llc_set_station_handler(NULL);
}
|
