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Commit | Line | Data |
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1da177e4 LT |
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> | |
c752f073 | 24 | #include <net/tcp_states.h> |
1da177e4 | 25 | #include <linux/llc.h> |
5a0e3ad6 | 26 | #include <linux/slab.h> |
1da177e4 | 27 | |
f83f1768 JP |
28 | static int llc_mac_header_len(unsigned short devtype) |
29 | { | |
30 | switch (devtype) { | |
31 | case ARPHRD_ETHER: | |
32 | case ARPHRD_LOOPBACK: | |
33 | return sizeof(struct ethhdr); | |
f83f1768 JP |
34 | } |
35 | return 0; | |
36 | } | |
37 | ||
1da177e4 LT |
38 | /** |
39 | * llc_alloc_frame - allocates sk_buff for frame | |
1d67e650 | 40 | * @dev: network device this skb will be sent over |
f83f1768 JP |
41 | * @type: pdu type to allocate |
42 | * @data_size: data size to allocate | |
1da177e4 LT |
43 | * |
44 | * Allocates an sk_buff for frame and initializes sk_buff fields. | |
45 | * Returns allocated skb or %NULL when out of memory. | |
46 | */ | |
f83f1768 JP |
47 | struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev, |
48 | u8 type, u32 data_size) | |
1da177e4 | 49 | { |
f83f1768 JP |
50 | int hlen = type == LLC_PDU_TYPE_U ? 3 : 4; |
51 | struct sk_buff *skb; | |
52 | ||
53 | hlen += llc_mac_header_len(dev->type); | |
54 | skb = alloc_skb(hlen + data_size, GFP_ATOMIC); | |
1da177e4 LT |
55 | |
56 | if (skb) { | |
0a1b0ad9 | 57 | skb_reset_mac_header(skb); |
f83f1768 | 58 | skb_reserve(skb, hlen); |
c1d2bbe1 | 59 | skb_reset_network_header(skb); |
badff6d0 | 60 | skb_reset_transport_header(skb); |
1da177e4 | 61 | skb->protocol = htons(ETH_P_802_2); |
1d67e650 | 62 | skb->dev = dev; |
d389424e ACM |
63 | if (sk != NULL) |
64 | skb_set_owner_w(skb, sk); | |
1da177e4 LT |
65 | } |
66 | return skb; | |
67 | } | |
68 | ||
3cdba604 | 69 | void llc_save_primitive(struct sock *sk, struct sk_buff *skb, u8 prim) |
1da177e4 | 70 | { |
8420e1b5 | 71 | struct sockaddr_llc *addr; |
1da177e4 LT |
72 | |
73 | /* save primitive for use by the user. */ | |
8420e1b5 | 74 | addr = llc_ui_skb_cb(skb); |
30a584d9 SH |
75 | |
76 | memset(addr, 0, sizeof(*addr)); | |
04e4223f | 77 | addr->sllc_family = sk->sk_family; |
1da177e4 LT |
78 | addr->sllc_arphrd = skb->dev->type; |
79 | addr->sllc_test = prim == LLC_TEST_PRIM; | |
80 | addr->sllc_xid = prim == LLC_XID_PRIM; | |
81 | addr->sllc_ua = prim == LLC_DATAUNIT_PRIM; | |
82 | llc_pdu_decode_sa(skb, addr->sllc_mac); | |
83 | llc_pdu_decode_ssap(skb, &addr->sllc_sap); | |
84 | } | |
85 | ||
86 | /** | |
87 | * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu. | |
88 | * @sap: pointer to SAP | |
89 | * @skb: received pdu | |
90 | */ | |
91 | void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb) | |
92 | { | |
93 | struct llc_sap_state_ev *ev = llc_sap_ev(skb); | |
94 | struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); | |
95 | ||
96 | switch (LLC_U_PDU_RSP(pdu)) { | |
97 | case LLC_1_PDU_CMD_TEST: | |
98 | ev->prim = LLC_TEST_PRIM; break; | |
99 | case LLC_1_PDU_CMD_XID: | |
100 | ev->prim = LLC_XID_PRIM; break; | |
101 | case LLC_1_PDU_CMD_UI: | |
102 | ev->prim = LLC_DATAUNIT_PRIM; break; | |
103 | } | |
104 | ev->ind_cfm_flag = LLC_IND; | |
105 | } | |
106 | ||
107 | /** | |
108 | * llc_find_sap_trans - finds transition for event | |
109 | * @sap: pointer to SAP | |
110 | * @skb: happened event | |
111 | * | |
112 | * This function finds transition that matches with happened event. | |
113 | * Returns the pointer to found transition on success or %NULL for | |
114 | * failure. | |
115 | */ | |
116 | static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap, | |
3cdba604 | 117 | struct sk_buff *skb) |
1da177e4 LT |
118 | { |
119 | int i = 0; | |
120 | struct llc_sap_state_trans *rc = NULL; | |
121 | struct llc_sap_state_trans **next_trans; | |
122 | struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1]; | |
123 | /* | |
124 | * Search thru events for this state until list exhausted or until | |
125 | * its obvious the event is not valid for the current state | |
126 | */ | |
127 | for (next_trans = curr_state->transitions; next_trans[i]->ev; i++) | |
128 | if (!next_trans[i]->ev(sap, skb)) { | |
129 | rc = next_trans[i]; /* got event match; return it */ | |
130 | break; | |
131 | } | |
132 | return rc; | |
133 | } | |
134 | ||
135 | /** | |
136 | * llc_exec_sap_trans_actions - execute actions related to event | |
137 | * @sap: pointer to SAP | |
138 | * @trans: pointer to transition that it's actions must be performed | |
139 | * @skb: happened event. | |
140 | * | |
141 | * This function executes actions that is related to happened event. | |
142 | * Returns 0 for success and 1 for failure of at least one action. | |
143 | */ | |
144 | static int llc_exec_sap_trans_actions(struct llc_sap *sap, | |
145 | struct llc_sap_state_trans *trans, | |
146 | struct sk_buff *skb) | |
147 | { | |
148 | int rc = 0; | |
22bbf5f3 | 149 | const llc_sap_action_t *next_action = trans->ev_actions; |
1da177e4 LT |
150 | |
151 | for (; next_action && *next_action; next_action++) | |
152 | if ((*next_action)(sap, skb)) | |
153 | rc = 1; | |
154 | return rc; | |
155 | } | |
156 | ||
157 | /** | |
158 | * llc_sap_next_state - finds transition, execs actions & change SAP state | |
159 | * @sap: pointer to SAP | |
160 | * @skb: happened event | |
161 | * | |
162 | * This function finds transition that matches with happened event, then | |
163 | * executes related actions and finally changes state of SAP. It returns | |
164 | * 0 on success and 1 for failure. | |
165 | */ | |
166 | static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb) | |
167 | { | |
168 | int rc = 1; | |
169 | struct llc_sap_state_trans *trans; | |
170 | ||
171 | if (sap->state > LLC_NR_SAP_STATES) | |
172 | goto out; | |
173 | trans = llc_find_sap_trans(sap, skb); | |
174 | if (!trans) | |
175 | goto out; | |
176 | /* | |
177 | * Got the state to which we next transition; perform the actions | |
178 | * associated with this transition before actually transitioning to the | |
179 | * next state | |
180 | */ | |
181 | rc = llc_exec_sap_trans_actions(sap, trans, skb); | |
182 | if (rc) | |
183 | goto out; | |
184 | /* | |
185 | * Transition SAP to next state if all actions execute successfully | |
186 | */ | |
187 | sap->state = trans->next_state; | |
188 | out: | |
189 | return rc; | |
190 | } | |
191 | ||
192 | /** | |
193 | * llc_sap_state_process - sends event to SAP state machine | |
194 | * @sap: sap to use | |
195 | * @skb: pointer to occurred event | |
196 | * | |
197 | * After executing actions of the event, upper layer will be indicated | |
198 | * if needed(on receiving an UI frame). sk can be null for the | |
199 | * datalink_proto case. | |
200 | */ | |
201 | static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb) | |
202 | { | |
203 | struct llc_sap_state_ev *ev = llc_sap_ev(skb); | |
204 | ||
205 | /* | |
206 | * We have to hold the skb, because llc_sap_next_state | |
207 | * will kfree it in the sending path and we need to | |
208 | * look at the skb->cb, where we encode llc_sap_state_ev. | |
209 | */ | |
210 | skb_get(skb); | |
211 | ev->ind_cfm_flag = 0; | |
212 | llc_sap_next_state(sap, skb); | |
213 | if (ev->ind_cfm_flag == LLC_IND) { | |
214 | if (skb->sk->sk_state == TCP_LISTEN) | |
215 | kfree_skb(skb); | |
216 | else { | |
04e4223f | 217 | llc_save_primitive(skb->sk, skb, ev->prim); |
1da177e4 LT |
218 | |
219 | /* queue skb to the user. */ | |
220 | if (sock_queue_rcv_skb(skb->sk, skb)) | |
221 | kfree_skb(skb); | |
222 | } | |
d57b1869 | 223 | } |
1da177e4 LT |
224 | kfree_skb(skb); |
225 | } | |
226 | ||
227 | /** | |
228 | * llc_build_and_send_test_pkt - TEST interface for upper layers. | |
229 | * @sap: sap to use | |
230 | * @skb: packet to send | |
231 | * @dmac: destination mac address | |
232 | * @dsap: destination sap | |
233 | * | |
234 | * This function is called when upper layer wants to send a TEST pdu. | |
235 | * Returns 0 for success, 1 otherwise. | |
236 | */ | |
d57b1869 | 237 | void llc_build_and_send_test_pkt(struct llc_sap *sap, |
1da177e4 LT |
238 | struct sk_buff *skb, u8 *dmac, u8 dsap) |
239 | { | |
240 | struct llc_sap_state_ev *ev = llc_sap_ev(skb); | |
241 | ||
242 | ev->saddr.lsap = sap->laddr.lsap; | |
243 | ev->daddr.lsap = dsap; | |
244 | memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); | |
245 | memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); | |
d57b1869 | 246 | |
1da177e4 LT |
247 | ev->type = LLC_SAP_EV_TYPE_PRIM; |
248 | ev->prim = LLC_TEST_PRIM; | |
249 | ev->prim_type = LLC_PRIM_TYPE_REQ; | |
250 | llc_sap_state_process(sap, skb); | |
251 | } | |
252 | ||
253 | /** | |
254 | * llc_build_and_send_xid_pkt - XID interface for upper layers | |
255 | * @sap: sap to use | |
256 | * @skb: packet to send | |
257 | * @dmac: destination mac address | |
258 | * @dsap: destination sap | |
259 | * | |
260 | * This function is called when upper layer wants to send a XID pdu. | |
261 | * Returns 0 for success, 1 otherwise. | |
262 | */ | |
263 | void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb, | |
264 | u8 *dmac, u8 dsap) | |
265 | { | |
266 | struct llc_sap_state_ev *ev = llc_sap_ev(skb); | |
267 | ||
268 | ev->saddr.lsap = sap->laddr.lsap; | |
269 | ev->daddr.lsap = dsap; | |
270 | memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); | |
271 | memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); | |
272 | ||
273 | ev->type = LLC_SAP_EV_TYPE_PRIM; | |
274 | ev->prim = LLC_XID_PRIM; | |
275 | ev->prim_type = LLC_PRIM_TYPE_REQ; | |
276 | llc_sap_state_process(sap, skb); | |
277 | } | |
278 | ||
279 | /** | |
280 | * llc_sap_rcv - sends received pdus to the sap state machine | |
281 | * @sap: current sap component structure. | |
282 | * @skb: received frame. | |
283 | * | |
284 | * Sends received pdus to the sap state machine. | |
285 | */ | |
3446b9d5 ACM |
286 | static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb, |
287 | struct sock *sk) | |
1da177e4 LT |
288 | { |
289 | struct llc_sap_state_ev *ev = llc_sap_ev(skb); | |
290 | ||
291 | ev->type = LLC_SAP_EV_TYPE_PDU; | |
292 | ev->reason = 0; | |
8b74d439 ED |
293 | skb_orphan(skb); |
294 | sock_hold(sk); | |
3446b9d5 | 295 | skb->sk = sk; |
8b74d439 | 296 | skb->destructor = sock_efree; |
1da177e4 LT |
297 | llc_sap_state_process(sap, skb); |
298 | } | |
299 | ||
b76f5a84 OP |
300 | static inline bool llc_dgram_match(const struct llc_sap *sap, |
301 | const struct llc_addr *laddr, | |
302 | const struct sock *sk) | |
303 | { | |
304 | struct llc_sock *llc = llc_sk(sk); | |
305 | ||
306 | return sk->sk_type == SOCK_DGRAM && | |
307 | llc->laddr.lsap == laddr->lsap && | |
951fd874 | 308 | ether_addr_equal(llc->laddr.mac, laddr->mac); |
b76f5a84 OP |
309 | } |
310 | ||
1da177e4 LT |
311 | /** |
312 | * llc_lookup_dgram - Finds dgram socket for the local sap/mac | |
313 | * @sap: SAP | |
314 | * @laddr: address of local LLC (MAC + SAP) | |
315 | * | |
316 | * Search socket list of the SAP and finds connection using the local | |
317 | * mac, and local sap. Returns pointer for socket found, %NULL otherwise. | |
318 | */ | |
319 | static struct sock *llc_lookup_dgram(struct llc_sap *sap, | |
bc0e6467 | 320 | const struct llc_addr *laddr) |
1da177e4 LT |
321 | { |
322 | struct sock *rc; | |
b76f5a84 | 323 | struct hlist_nulls_node *node; |
52d58aef OP |
324 | int slot = llc_sk_laddr_hashfn(sap, laddr); |
325 | struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot]; | |
b76f5a84 OP |
326 | |
327 | rcu_read_lock_bh(); | |
328 | again: | |
52d58aef | 329 | sk_nulls_for_each_rcu(rc, node, laddr_hb) { |
b76f5a84 | 330 | if (llc_dgram_match(sap, laddr, rc)) { |
5f0d5a3a | 331 | /* Extra checks required by SLAB_TYPESAFE_BY_RCU */ |
41c6d650 | 332 | if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt))) |
b76f5a84 OP |
333 | goto again; |
334 | if (unlikely(llc_sk(rc)->sap != sap || | |
335 | !llc_dgram_match(sap, laddr, rc))) { | |
336 | sock_put(rc); | |
337 | continue; | |
338 | } | |
1da177e4 LT |
339 | goto found; |
340 | } | |
341 | } | |
342 | rc = NULL; | |
52d58aef OP |
343 | /* |
344 | * if the nulls value we got at the end of this lookup is | |
345 | * not the expected one, we must restart lookup. | |
346 | * We probably met an item that was moved to another chain. | |
347 | */ | |
348 | if (unlikely(get_nulls_value(node) != slot)) | |
349 | goto again; | |
1da177e4 | 350 | found: |
b76f5a84 | 351 | rcu_read_unlock_bh(); |
1da177e4 LT |
352 | return rc; |
353 | } | |
354 | ||
b76f5a84 OP |
355 | static inline bool llc_mcast_match(const struct llc_sap *sap, |
356 | const struct llc_addr *laddr, | |
357 | const struct sk_buff *skb, | |
358 | const struct sock *sk) | |
359 | { | |
360 | struct llc_sock *llc = llc_sk(sk); | |
361 | ||
362 | return sk->sk_type == SOCK_DGRAM && | |
363 | llc->laddr.lsap == laddr->lsap && | |
364 | llc->dev == skb->dev; | |
365 | } | |
366 | ||
0f7b67dd OP |
367 | static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb, |
368 | struct sock **stack, int count) | |
369 | { | |
370 | struct sk_buff *skb1; | |
371 | int i; | |
372 | ||
373 | for (i = 0; i < count; i++) { | |
374 | skb1 = skb_clone(skb, GFP_ATOMIC); | |
375 | if (!skb1) { | |
376 | sock_put(stack[i]); | |
377 | continue; | |
378 | } | |
379 | ||
380 | llc_sap_rcv(sap, skb1, stack[i]); | |
381 | sock_put(stack[i]); | |
382 | } | |
383 | } | |
384 | ||
bc0e6467 SH |
385 | /** |
386 | * llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets. | |
387 | * @sap: SAP | |
388 | * @laddr: address of local LLC (MAC + SAP) | |
389 | * | |
390 | * Search socket list of the SAP and finds connections with same sap. | |
391 | * Deliver clone to each. | |
392 | */ | |
393 | static void llc_sap_mcast(struct llc_sap *sap, | |
394 | const struct llc_addr *laddr, | |
395 | struct sk_buff *skb) | |
396 | { | |
678f4bda SM |
397 | int i = 0; |
398 | struct sock *sk; | |
399 | struct sock *stack[256 / sizeof(struct sock *)]; | |
6d2e3ea2 OP |
400 | struct llc_sock *llc; |
401 | struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex); | |
bc0e6467 | 402 | |
b76f5a84 | 403 | spin_lock_bh(&sap->sk_lock); |
b67bfe0d | 404 | hlist_for_each_entry(llc, dev_hb, dev_hash_node) { |
6d2e3ea2 OP |
405 | |
406 | sk = &llc->sk; | |
bc0e6467 | 407 | |
b76f5a84 | 408 | if (!llc_mcast_match(sap, laddr, skb, sk)) |
7ee66fcb SH |
409 | continue; |
410 | ||
bc0e6467 | 411 | sock_hold(sk); |
678f4bda | 412 | if (i < ARRAY_SIZE(stack)) |
0f7b67dd OP |
413 | stack[i++] = sk; |
414 | else { | |
415 | llc_do_mcast(sap, skb, stack, i); | |
416 | i = 0; | |
417 | } | |
bc0e6467 | 418 | } |
b76f5a84 | 419 | spin_unlock_bh(&sap->sk_lock); |
0f7b67dd OP |
420 | |
421 | llc_do_mcast(sap, skb, stack, i); | |
bc0e6467 SH |
422 | } |
423 | ||
424 | ||
1da177e4 LT |
425 | void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb) |
426 | { | |
427 | struct llc_addr laddr; | |
1da177e4 LT |
428 | |
429 | llc_pdu_decode_da(skb, laddr.mac); | |
430 | llc_pdu_decode_dsap(skb, &laddr.lsap); | |
431 | ||
951fd874 | 432 | if (is_multicast_ether_addr(laddr.mac)) { |
bc0e6467 | 433 | llc_sap_mcast(sap, &laddr, skb); |
1da177e4 | 434 | kfree_skb(skb); |
bc0e6467 SH |
435 | } else { |
436 | struct sock *sk = llc_lookup_dgram(sap, &laddr); | |
437 | if (sk) { | |
3446b9d5 | 438 | llc_sap_rcv(sap, skb, sk); |
bc0e6467 SH |
439 | sock_put(sk); |
440 | } else | |
441 | kfree_skb(skb); | |
442 | } | |
1da177e4 | 443 | } |