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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 <net/tcp_states.h>
25#include <linux/llc.h>
26#include <linux/slab.h>
27
28static 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);
34#if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
35 case ARPHRD_IEEE802_TR:
36 return sizeof(struct trh_hdr);
37#endif
38 }
39 return 0;
40}
41
42
43
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46
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48
49
50
51struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev,
52 u8 type, u32 data_size)
53{
54 int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
55 struct sk_buff *skb;
56
57 hlen += llc_mac_header_len(dev->type);
58 skb = alloc_skb(hlen + data_size, GFP_ATOMIC);
59
60 if (skb) {
61 skb_reset_mac_header(skb);
62 skb_reserve(skb, hlen);
63 skb_reset_network_header(skb);
64 skb_reset_transport_header(skb);
65 skb->protocol = htons(ETH_P_802_2);
66 skb->dev = dev;
67 if (sk != NULL)
68 skb_set_owner_w(skb, sk);
69 }
70 return skb;
71}
72
73void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim)
74{
75 struct sockaddr_llc *addr;
76
77
78 addr = llc_ui_skb_cb(skb);
79
80 memset(addr, 0, sizeof(*addr));
81 addr->sllc_family = sk->sk_family;
82 addr->sllc_arphrd = skb->dev->type;
83 addr->sllc_test = prim == LLC_TEST_PRIM;
84 addr->sllc_xid = prim == LLC_XID_PRIM;
85 addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
86 llc_pdu_decode_sa(skb, addr->sllc_mac);
87 llc_pdu_decode_ssap(skb, &addr->sllc_sap);
88}
89
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93
94
95void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb)
96{
97 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
98 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
99
100 switch (LLC_U_PDU_RSP(pdu)) {
101 case LLC_1_PDU_CMD_TEST:
102 ev->prim = LLC_TEST_PRIM; break;
103 case LLC_1_PDU_CMD_XID:
104 ev->prim = LLC_XID_PRIM; break;
105 case LLC_1_PDU_CMD_UI:
106 ev->prim = LLC_DATAUNIT_PRIM; break;
107 }
108 ev->ind_cfm_flag = LLC_IND;
109}
110
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119
120static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
121 struct sk_buff* skb)
122{
123 int i = 0;
124 struct llc_sap_state_trans *rc = NULL;
125 struct llc_sap_state_trans **next_trans;
126 struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
127
128
129
130
131 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
132 if (!next_trans[i]->ev(sap, skb)) {
133 rc = next_trans[i];
134 break;
135 }
136 return rc;
137}
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147
148static int llc_exec_sap_trans_actions(struct llc_sap *sap,
149 struct llc_sap_state_trans *trans,
150 struct sk_buff *skb)
151{
152 int rc = 0;
153 llc_sap_action_t *next_action = trans->ev_actions;
154
155 for (; next_action && *next_action; next_action++)
156 if ((*next_action)(sap, skb))
157 rc = 1;
158 return rc;
159}
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169
170static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
171{
172 int rc = 1;
173 struct llc_sap_state_trans *trans;
174
175 if (sap->state > LLC_NR_SAP_STATES)
176 goto out;
177 trans = llc_find_sap_trans(sap, skb);
178 if (!trans)
179 goto out;
180
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184
185 rc = llc_exec_sap_trans_actions(sap, trans, skb);
186 if (rc)
187 goto out;
188
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190
191 sap->state = trans->next_state;
192out:
193 return rc;
194}
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204
205static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
206{
207 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
208
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213
214 skb_get(skb);
215 ev->ind_cfm_flag = 0;
216 llc_sap_next_state(sap, skb);
217 if (ev->ind_cfm_flag == LLC_IND) {
218 if (skb->sk->sk_state == TCP_LISTEN)
219 kfree_skb(skb);
220 else {
221 llc_save_primitive(skb->sk, skb, ev->prim);
222
223
224 if (sock_queue_rcv_skb(skb->sk, skb))
225 kfree_skb(skb);
226 }
227 }
228 kfree_skb(skb);
229}
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240
241void llc_build_and_send_test_pkt(struct llc_sap *sap,
242 struct sk_buff *skb, u8 *dmac, u8 dsap)
243{
244 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
245
246 ev->saddr.lsap = sap->laddr.lsap;
247 ev->daddr.lsap = dsap;
248 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
249 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
250
251 ev->type = LLC_SAP_EV_TYPE_PRIM;
252 ev->prim = LLC_TEST_PRIM;
253 ev->prim_type = LLC_PRIM_TYPE_REQ;
254 llc_sap_state_process(sap, skb);
255}
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266
267void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
268 u8 *dmac, u8 dsap)
269{
270 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
271
272 ev->saddr.lsap = sap->laddr.lsap;
273 ev->daddr.lsap = dsap;
274 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
275 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
276
277 ev->type = LLC_SAP_EV_TYPE_PRIM;
278 ev->prim = LLC_XID_PRIM;
279 ev->prim_type = LLC_PRIM_TYPE_REQ;
280 llc_sap_state_process(sap, skb);
281}
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290static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
291 struct sock *sk)
292{
293 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
294
295 ev->type = LLC_SAP_EV_TYPE_PDU;
296 ev->reason = 0;
297 skb->sk = sk;
298 llc_sap_state_process(sap, skb);
299}
300
301static inline bool llc_dgram_match(const struct llc_sap *sap,
302 const struct llc_addr *laddr,
303 const struct sock *sk)
304{
305 struct llc_sock *llc = llc_sk(sk);
306
307 return sk->sk_type == SOCK_DGRAM &&
308 llc->laddr.lsap == laddr->lsap &&
309 llc_mac_match(llc->laddr.mac, laddr->mac);
310}
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320static struct sock *llc_lookup_dgram(struct llc_sap *sap,
321 const struct llc_addr *laddr)
322{
323 struct sock *rc;
324 struct hlist_nulls_node *node;
325 int slot = llc_sk_laddr_hashfn(sap, laddr);
326 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
327
328 rcu_read_lock_bh();
329again:
330 sk_nulls_for_each_rcu(rc, node, laddr_hb) {
331 if (llc_dgram_match(sap, laddr, rc)) {
332
333 if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
334 goto again;
335 if (unlikely(llc_sk(rc)->sap != sap ||
336 !llc_dgram_match(sap, laddr, rc))) {
337 sock_put(rc);
338 continue;
339 }
340 goto found;
341 }
342 }
343 rc = NULL;
344
345
346
347
348
349 if (unlikely(get_nulls_value(node) != slot))
350 goto again;
351found:
352 rcu_read_unlock_bh();
353 return rc;
354}
355
356static inline bool llc_mcast_match(const struct llc_sap *sap,
357 const struct llc_addr *laddr,
358 const struct sk_buff *skb,
359 const struct sock *sk)
360{
361 struct llc_sock *llc = llc_sk(sk);
362
363 return sk->sk_type == SOCK_DGRAM &&
364 llc->laddr.lsap == laddr->lsap &&
365 llc->dev == skb->dev;
366}
367
368static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb,
369 struct sock **stack, int count)
370{
371 struct sk_buff *skb1;
372 int i;
373
374 for (i = 0; i < count; i++) {
375 skb1 = skb_clone(skb, GFP_ATOMIC);
376 if (!skb1) {
377 sock_put(stack[i]);
378 continue;
379 }
380
381 llc_sap_rcv(sap, skb1, stack[i]);
382 sock_put(stack[i]);
383 }
384}
385
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393
394static void llc_sap_mcast(struct llc_sap *sap,
395 const struct llc_addr *laddr,
396 struct sk_buff *skb)
397{
398 int i = 0, count = 256 / sizeof(struct sock *);
399 struct sock *sk, *stack[count];
400 struct hlist_node *node;
401 struct llc_sock *llc;
402 struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
403
404 spin_lock_bh(&sap->sk_lock);
405 hlist_for_each_entry(llc, node, dev_hb, dev_hash_node) {
406
407 sk = &llc->sk;
408
409 if (!llc_mcast_match(sap, laddr, skb, sk))
410 continue;
411
412 sock_hold(sk);
413 if (i < count)
414 stack[i++] = sk;
415 else {
416 llc_do_mcast(sap, skb, stack, i);
417 i = 0;
418 }
419 }
420 spin_unlock_bh(&sap->sk_lock);
421
422 llc_do_mcast(sap, skb, stack, i);
423}
424
425
426void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
427{
428 struct llc_addr laddr;
429
430 llc_pdu_decode_da(skb, laddr.mac);
431 llc_pdu_decode_dsap(skb, &laddr.lsap);
432
433 if (llc_mac_multicast(laddr.mac)) {
434 llc_sap_mcast(sap, &laddr, skb);
435 kfree_skb(skb);
436 } else {
437 struct sock *sk = llc_lookup_dgram(sap, &laddr);
438 if (sk) {
439 llc_sap_rcv(sap, skb, sk);
440 sock_put(sk);
441 } else
442 kfree_skb(skb);
443 }
444}
445