blob: 2525165e2e8fdb8a53e774f82f72f8acba4eb94e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070024#include <net/tcp_states.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/llc.h>
26
27/**
28 * llc_alloc_frame - allocates sk_buff for frame
Arnaldo Carvalho de Melo1d67e652005-09-22 03:27:56 -030029 * @dev: network device this skb will be sent over
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 *
31 * Allocates an sk_buff for frame and initializes sk_buff fields.
32 * Returns allocated skb or %NULL when out of memory.
33 */
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -030034struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035{
36 struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC);
37
38 if (skb) {
Arnaldo Carvalho de Melo0a1b0ad92007-03-10 12:14:56 -030039 skb_reset_mac_header(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 skb_reserve(skb, 50);
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -070041 skb_reset_network_header(skb);
Arnaldo Carvalho de Melobadff6d2007-03-13 13:06:52 -030042 skb_reset_transport_header(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 skb->protocol = htons(ETH_P_802_2);
Arnaldo Carvalho de Melo1d67e652005-09-22 03:27:56 -030044 skb->dev = dev;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -030045 if (sk != NULL)
46 skb_set_owner_w(skb, sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 }
48 return skb;
49}
50
Arnaldo Carvalho de Melo04e42232005-09-22 04:40:59 -030051void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052{
Arnaldo Carvalho de Melo8420e1b2005-09-22 08:29:08 -030053 struct sockaddr_llc *addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
55 /* save primitive for use by the user. */
Arnaldo Carvalho de Melo8420e1b2005-09-22 08:29:08 -030056 addr = llc_ui_skb_cb(skb);
Stephen Hemminger30a584d2006-08-03 16:38:49 -070057
58 memset(addr, 0, sizeof(*addr));
Arnaldo Carvalho de Melo04e42232005-09-22 04:40:59 -030059 addr->sllc_family = sk->sk_family;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 addr->sllc_arphrd = skb->dev->type;
61 addr->sllc_test = prim == LLC_TEST_PRIM;
62 addr->sllc_xid = prim == LLC_XID_PRIM;
63 addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
64 llc_pdu_decode_sa(skb, addr->sllc_mac);
65 llc_pdu_decode_ssap(skb, &addr->sllc_sap);
66}
67
68/**
69 * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
70 * @sap: pointer to SAP
71 * @skb: received pdu
72 */
73void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb)
74{
75 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
76 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
77
78 switch (LLC_U_PDU_RSP(pdu)) {
79 case LLC_1_PDU_CMD_TEST:
80 ev->prim = LLC_TEST_PRIM; break;
81 case LLC_1_PDU_CMD_XID:
82 ev->prim = LLC_XID_PRIM; break;
83 case LLC_1_PDU_CMD_UI:
84 ev->prim = LLC_DATAUNIT_PRIM; break;
85 }
86 ev->ind_cfm_flag = LLC_IND;
87}
88
89/**
90 * llc_find_sap_trans - finds transition for event
91 * @sap: pointer to SAP
92 * @skb: happened event
93 *
94 * This function finds transition that matches with happened event.
95 * Returns the pointer to found transition on success or %NULL for
96 * failure.
97 */
98static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
99 struct sk_buff* skb)
100{
101 int i = 0;
102 struct llc_sap_state_trans *rc = NULL;
103 struct llc_sap_state_trans **next_trans;
104 struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
105 /*
106 * Search thru events for this state until list exhausted or until
107 * its obvious the event is not valid for the current state
108 */
109 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
110 if (!next_trans[i]->ev(sap, skb)) {
111 rc = next_trans[i]; /* got event match; return it */
112 break;
113 }
114 return rc;
115}
116
117/**
118 * llc_exec_sap_trans_actions - execute actions related to event
119 * @sap: pointer to SAP
120 * @trans: pointer to transition that it's actions must be performed
121 * @skb: happened event.
122 *
123 * This function executes actions that is related to happened event.
124 * Returns 0 for success and 1 for failure of at least one action.
125 */
126static int llc_exec_sap_trans_actions(struct llc_sap *sap,
127 struct llc_sap_state_trans *trans,
128 struct sk_buff *skb)
129{
130 int rc = 0;
131 llc_sap_action_t *next_action = trans->ev_actions;
132
133 for (; next_action && *next_action; next_action++)
134 if ((*next_action)(sap, skb))
135 rc = 1;
136 return rc;
137}
138
139/**
140 * llc_sap_next_state - finds transition, execs actions & change SAP state
141 * @sap: pointer to SAP
142 * @skb: happened event
143 *
144 * This function finds transition that matches with happened event, then
145 * executes related actions and finally changes state of SAP. It returns
146 * 0 on success and 1 for failure.
147 */
148static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
149{
150 int rc = 1;
151 struct llc_sap_state_trans *trans;
152
153 if (sap->state > LLC_NR_SAP_STATES)
154 goto out;
155 trans = llc_find_sap_trans(sap, skb);
156 if (!trans)
157 goto out;
158 /*
159 * Got the state to which we next transition; perform the actions
160 * associated with this transition before actually transitioning to the
161 * next state
162 */
163 rc = llc_exec_sap_trans_actions(sap, trans, skb);
164 if (rc)
165 goto out;
166 /*
167 * Transition SAP to next state if all actions execute successfully
168 */
169 sap->state = trans->next_state;
170out:
171 return rc;
172}
173
174/**
175 * llc_sap_state_process - sends event to SAP state machine
176 * @sap: sap to use
177 * @skb: pointer to occurred event
178 *
179 * After executing actions of the event, upper layer will be indicated
180 * if needed(on receiving an UI frame). sk can be null for the
181 * datalink_proto case.
182 */
183static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
184{
185 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
186
187 /*
188 * We have to hold the skb, because llc_sap_next_state
189 * will kfree it in the sending path and we need to
190 * look at the skb->cb, where we encode llc_sap_state_ev.
191 */
192 skb_get(skb);
193 ev->ind_cfm_flag = 0;
194 llc_sap_next_state(sap, skb);
195 if (ev->ind_cfm_flag == LLC_IND) {
196 if (skb->sk->sk_state == TCP_LISTEN)
197 kfree_skb(skb);
198 else {
Arnaldo Carvalho de Melo04e42232005-09-22 04:40:59 -0300199 llc_save_primitive(skb->sk, skb, ev->prim);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
201 /* queue skb to the user. */
202 if (sock_queue_rcv_skb(skb->sk, skb))
203 kfree_skb(skb);
204 }
YOSHIFUJI Hideakid57b1862007-02-09 23:25:01 +0900205 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 kfree_skb(skb);
207}
208
209/**
210 * llc_build_and_send_test_pkt - TEST interface for upper layers.
211 * @sap: sap to use
212 * @skb: packet to send
213 * @dmac: destination mac address
214 * @dsap: destination sap
215 *
216 * This function is called when upper layer wants to send a TEST pdu.
217 * Returns 0 for success, 1 otherwise.
218 */
YOSHIFUJI Hideakid57b1862007-02-09 23:25:01 +0900219void llc_build_and_send_test_pkt(struct llc_sap *sap,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 struct sk_buff *skb, u8 *dmac, u8 dsap)
221{
222 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
223
224 ev->saddr.lsap = sap->laddr.lsap;
225 ev->daddr.lsap = dsap;
226 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
227 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
YOSHIFUJI Hideakid57b1862007-02-09 23:25:01 +0900228
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 ev->type = LLC_SAP_EV_TYPE_PRIM;
230 ev->prim = LLC_TEST_PRIM;
231 ev->prim_type = LLC_PRIM_TYPE_REQ;
232 llc_sap_state_process(sap, skb);
233}
234
235/**
236 * llc_build_and_send_xid_pkt - XID interface for upper layers
237 * @sap: sap to use
238 * @skb: packet to send
239 * @dmac: destination mac address
240 * @dsap: destination sap
241 *
242 * This function is called when upper layer wants to send a XID pdu.
243 * Returns 0 for success, 1 otherwise.
244 */
245void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
246 u8 *dmac, u8 dsap)
247{
248 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
249
250 ev->saddr.lsap = sap->laddr.lsap;
251 ev->daddr.lsap = dsap;
252 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
253 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
254
255 ev->type = LLC_SAP_EV_TYPE_PRIM;
256 ev->prim = LLC_XID_PRIM;
257 ev->prim_type = LLC_PRIM_TYPE_REQ;
258 llc_sap_state_process(sap, skb);
259}
260
261/**
262 * llc_sap_rcv - sends received pdus to the sap state machine
263 * @sap: current sap component structure.
264 * @skb: received frame.
265 *
266 * Sends received pdus to the sap state machine.
267 */
268static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb)
269{
270 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
271
272 ev->type = LLC_SAP_EV_TYPE_PDU;
273 ev->reason = 0;
274 llc_sap_state_process(sap, skb);
275}
276
277/**
278 * llc_lookup_dgram - Finds dgram socket for the local sap/mac
279 * @sap: SAP
280 * @laddr: address of local LLC (MAC + SAP)
281 *
282 * Search socket list of the SAP and finds connection using the local
283 * mac, and local sap. Returns pointer for socket found, %NULL otherwise.
284 */
285static struct sock *llc_lookup_dgram(struct llc_sap *sap,
Stephen Hemmingerbc0e6462006-05-25 15:10:37 -0700286 const struct llc_addr *laddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287{
288 struct sock *rc;
289 struct hlist_node *node;
290
291 read_lock_bh(&sap->sk_list.lock);
292 sk_for_each(rc, node, &sap->sk_list.list) {
293 struct llc_sock *llc = llc_sk(rc);
294
295 if (rc->sk_type == SOCK_DGRAM &&
296 llc->laddr.lsap == laddr->lsap &&
297 llc_mac_match(llc->laddr.mac, laddr->mac)) {
298 sock_hold(rc);
299 goto found;
300 }
301 }
302 rc = NULL;
303found:
304 read_unlock_bh(&sap->sk_list.lock);
305 return rc;
306}
307
Stephen Hemmingerbc0e6462006-05-25 15:10:37 -0700308/**
309 * llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
310 * @sap: SAP
311 * @laddr: address of local LLC (MAC + SAP)
312 *
313 * Search socket list of the SAP and finds connections with same sap.
314 * Deliver clone to each.
315 */
316static void llc_sap_mcast(struct llc_sap *sap,
317 const struct llc_addr *laddr,
318 struct sk_buff *skb)
319{
320 struct sock *sk;
321 struct hlist_node *node;
322
323 read_lock_bh(&sap->sk_list.lock);
324 sk_for_each(sk, node, &sap->sk_list.list) {
325 struct llc_sock *llc = llc_sk(sk);
326 struct sk_buff *skb1;
327
328 if (sk->sk_type != SOCK_DGRAM)
329 continue;
330
331 if (llc->laddr.lsap != laddr->lsap)
332 continue;
333
Stephen Hemminger7ee66fc2006-08-13 18:56:26 -0700334 if (llc->dev != skb->dev)
335 continue;
336
Stephen Hemmingerbc0e6462006-05-25 15:10:37 -0700337 skb1 = skb_clone(skb, GFP_ATOMIC);
338 if (!skb1)
339 break;
340
341 sock_hold(sk);
342 skb_set_owner_r(skb1, sk);
343 llc_sap_rcv(sap, skb1);
344 sock_put(sk);
345 }
346 read_unlock_bh(&sap->sk_list.lock);
347}
348
349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
351{
352 struct llc_addr laddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353
354 llc_pdu_decode_da(skb, laddr.mac);
355 llc_pdu_decode_dsap(skb, &laddr.lsap);
356
Stephen Hemmingerbc0e6462006-05-25 15:10:37 -0700357 if (llc_mac_multicast(laddr.mac)) {
358 llc_sap_mcast(sap, &laddr, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 kfree_skb(skb);
Stephen Hemmingerbc0e6462006-05-25 15:10:37 -0700360 } else {
361 struct sock *sk = llc_lookup_dgram(sap, &laddr);
362 if (sk) {
363 skb_set_owner_r(skb, sk);
364 llc_sap_rcv(sap, skb);
365 sock_put(sk);
366 } else
367 kfree_skb(skb);
368 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369}