1 /*
2 * llc_sap.c - driver routines for SAP component.
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
15 #include <net/llc.h>
16 #include <net/llc_if.h>
17 #include <net/llc_conn.h>
18 #include <net/llc_pdu.h>
19 #include <net/llc_sap.h>
20 #include <net/llc_s_ac.h>
21 #include <net/llc_s_ev.h>
22 #include <net/llc_s_st.h>
23 #include <net/sock.h>
24 #include <linux/tcp.h>
25 #include <linux/llc.h>
26
27 /**
28 * llc_alloc_frame - allocates sk_buff for frame
29 *
30 * Allocates an sk_buff for frame and initializes sk_buff fields.
31 * Returns allocated skb or %NULL when out of memory.
32 */
33 struct sk_buff *llc_alloc_frame(void)
34 {
35 struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC);
36
37 if (skb) {
38 skb_reserve(skb, 50);
39 skb->nh.raw = skb->h.raw = skb->data;
40 skb->protocol = htons(ETH_P_802_2);
41 skb->dev = dev_base->next;
42 skb->mac.raw = skb->head;
43 }
44 return skb;
45 }
46
47 void llc_save_primitive(struct sk_buff* skb, u8 prim)
48 {
49 struct sockaddr_llc *addr = llc_ui_skb_cb(skb);
50
51 /* save primitive for use by the user. */
52 addr->sllc_family = skb->sk->sk_family;
53 addr->sllc_arphrd = skb->dev->type;
54 addr->sllc_test = prim == LLC_TEST_PRIM;
55 addr->sllc_xid = prim == LLC_XID_PRIM;
56 addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
57 llc_pdu_decode_sa(skb, addr->sllc_mac);
58 llc_pdu_decode_ssap(skb, &addr->sllc_sap);
59 }
60
61 /**
62 * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
63 * @sap: pointer to SAP
64 * @skb: received pdu
65 */
66 void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb)
67 {
68 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
69 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
70
71 switch (LLC_U_PDU_RSP(pdu)) {
72 case LLC_1_PDU_CMD_TEST:
73 ev->prim = LLC_TEST_PRIM; break;
74 case LLC_1_PDU_CMD_XID:
75 ev->prim = LLC_XID_PRIM; break;
76 case LLC_1_PDU_CMD_UI:
77 ev->prim = LLC_DATAUNIT_PRIM; break;
78 }
79 ev->ind_cfm_flag = LLC_IND;
80 }
81
82 /**
83 * llc_find_sap_trans - finds transition for event
84 * @sap: pointer to SAP
85 * @skb: happened event
86 *
87 * This function finds transition that matches with happened event.
88 * Returns the pointer to found transition on success or %NULL for
89 * failure.
90 */
91 static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
92 struct sk_buff* skb)
93 {
94 int i = 0;
95 struct llc_sap_state_trans *rc = NULL;
96 struct llc_sap_state_trans **next_trans;
97 struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
98 /*
99 * Search thru events for this state until list exhausted or until
100 * its obvious the event is not valid for the current state
101 */
102 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
103 if (!next_trans[i]->ev(sap, skb)) {
104 rc = next_trans[i]; /* got event match; return it */
105 break;
106 }
107 return rc;
108 }
109
110 /**
111 * llc_exec_sap_trans_actions - execute actions related to event
112 * @sap: pointer to SAP
113 * @trans: pointer to transition that it's actions must be performed
114 * @skb: happened event.
115 *
116 * This function executes actions that is related to happened event.
117 * Returns 0 for success and 1 for failure of at least one action.
118 */
119 static int llc_exec_sap_trans_actions(struct llc_sap *sap,
120 struct llc_sap_state_trans *trans,
121 struct sk_buff *skb)
122 {
123 int rc = 0;
124 llc_sap_action_t *next_action = trans->ev_actions;
125
126 for (; next_action && *next_action; next_action++)
127 if ((*next_action)(sap, skb))
128 rc = 1;
129 return rc;
130 }
131
132 /**
133 * llc_sap_next_state - finds transition, execs actions & change SAP state
134 * @sap: pointer to SAP
135 * @skb: happened event
136 *
137 * This function finds transition that matches with happened event, then
138 * executes related actions and finally changes state of SAP. It returns
139 * 0 on success and 1 for failure.
140 */
141 static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
142 {
143 int rc = 1;
144 struct llc_sap_state_trans *trans;
145
146 if (sap->state > LLC_NR_SAP_STATES)
147 goto out;
148 trans = llc_find_sap_trans(sap, skb);
149 if (!trans)
150 goto out;
151 /*
152 * Got the state to which we next transition; perform the actions
153 * associated with this transition before actually transitioning to the
154 * next state
155 */
156 rc = llc_exec_sap_trans_actions(sap, trans, skb);
157 if (rc)
158 goto out;
159 /*
160 * Transition SAP to next state if all actions execute successfully
161 */
162 sap->state = trans->next_state;
163 out:
164 return rc;
165 }
166
167 /**
168 * llc_sap_state_process - sends event to SAP state machine
169 * @sap: sap to use
170 * @skb: pointer to occurred event
171 *
172 * After executing actions of the event, upper layer will be indicated
173 * if needed(on receiving an UI frame). sk can be null for the
174 * datalink_proto case.
175 */
176 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
177 {
178 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
179
180 /*
181 * We have to hold the skb, because llc_sap_next_state
182 * will kfree it in the sending path and we need to
183 * look at the skb->cb, where we encode llc_sap_state_ev.
184 */
185 skb_get(skb);
186 ev->ind_cfm_flag = 0;
187 llc_sap_next_state(sap, skb);
188 if (ev->ind_cfm_flag == LLC_IND) {
189 if (skb->sk->sk_state == TCP_LISTEN)
190 kfree_skb(skb);
191 else {
192 llc_save_primitive(skb, ev->prim);
193
194 /* queue skb to the user. */
195 if (sock_queue_rcv_skb(skb->sk, skb))
196 kfree_skb(skb);
197 }
198 }
199 kfree_skb(skb);
200 }
201
202 /**
203 * llc_build_and_send_test_pkt - TEST interface for upper layers.
204 * @sap: sap to use
205 * @skb: packet to send
206 * @dmac: destination mac address
207 * @dsap: destination sap
208 *
209 * This function is called when upper layer wants to send a TEST pdu.
210 * Returns 0 for success, 1 otherwise.
211 */
212 void llc_build_and_send_test_pkt(struct llc_sap *sap,
213 struct sk_buff *skb, u8 *dmac, u8 dsap)
214 {
215 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
216
217 ev->saddr.lsap = sap->laddr.lsap;
218 ev->daddr.lsap = dsap;
219 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
220 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
221
222 ev->type = LLC_SAP_EV_TYPE_PRIM;
223 ev->prim = LLC_TEST_PRIM;
224 ev->prim_type = LLC_PRIM_TYPE_REQ;
225 llc_sap_state_process(sap, skb);
226 }
227
228 /**
229 * llc_build_and_send_xid_pkt - XID interface for upper layers
230 * @sap: sap to use
231 * @skb: packet to send
232 * @dmac: destination mac address
233 * @dsap: destination sap
234 *
235 * This function is called when upper layer wants to send a XID pdu.
236 * Returns 0 for success, 1 otherwise.
237 */
238 void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
239 u8 *dmac, u8 dsap)
240 {
241 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
242
243 ev->saddr.lsap = sap->laddr.lsap;
244 ev->daddr.lsap = dsap;
245 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
246 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
247
248 ev->type = LLC_SAP_EV_TYPE_PRIM;
249 ev->prim = LLC_XID_PRIM;
250 ev->prim_type = LLC_PRIM_TYPE_REQ;
251 llc_sap_state_process(sap, skb);
252 }
253
254 /**
255 * llc_sap_rcv - sends received pdus to the sap state machine
256 * @sap: current sap component structure.
257 * @skb: received frame.
258 *
259 * Sends received pdus to the sap state machine.
260 */
261 static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb)
262 {
263 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
264
265 ev->type = LLC_SAP_EV_TYPE_PDU;
266 ev->reason = 0;
267 llc_sap_state_process(sap, skb);
268 }
269
270 /**
271 * llc_lookup_dgram - Finds dgram socket for the local sap/mac
272 * @sap: SAP
273 * @laddr: address of local LLC (MAC + SAP)
274 *
275 * Search socket list of the SAP and finds connection using the local
276 * mac, and local sap. Returns pointer for socket found, %NULL otherwise.
277 */
278 static struct sock *llc_lookup_dgram(struct llc_sap *sap,
279 struct llc_addr *laddr)
280 {
281 struct sock *rc;
282 struct hlist_node *node;
283
284 read_lock_bh(&sap->sk_list.lock);
285 sk_for_each(rc, node, &sap->sk_list.list) {
286 struct llc_opt *llc = llc_sk(rc);
287
288 if (rc->sk_type == SOCK_DGRAM &&
289 llc->laddr.lsap == laddr->lsap &&
290 llc_mac_match(llc->laddr.mac, laddr->mac)) {
291 sock_hold(rc);
292 goto found;
293 }
294 }
295 rc = NULL;
296 found:
297 read_unlock_bh(&sap->sk_list.lock);
298 return rc;
299 }
300
301 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
302 {
303 struct llc_addr laddr;
304 struct sock *sk;
305
306 llc_pdu_decode_da(skb, laddr.mac);
307 llc_pdu_decode_dsap(skb, &laddr.lsap);
308
309 sk = llc_lookup_dgram(sap, &laddr);
310 if (sk) {
311 skb->sk = sk;
312 llc_sap_rcv(sap, skb);
313 sock_put(sk);
314 } else
315 kfree_skb(skb);
316 }
317
|
This page was automatically generated by the
LXR engine.
|