This source file includes following definitions.
- llc_mac_header_len
- llc_alloc_frame
- llc_save_primitive
- llc_sap_rtn_pdu
- llc_find_sap_trans
- llc_exec_sap_trans_actions
- llc_sap_next_state
- llc_sap_state_process
- llc_build_and_send_test_pkt
- llc_build_and_send_xid_pkt
- llc_sap_rcv
- llc_dgram_match
- llc_lookup_dgram
- llc_mcast_match
- llc_do_mcast
- llc_sap_mcast
- llc_sap_handler
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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
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);
34 }
35 return 0;
36 }
37
38
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44
45
46
47 struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev,
48 u8 type, u32 data_size)
49 {
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);
55
56 if (skb) {
57 skb_reset_mac_header(skb);
58 skb_reserve(skb, hlen);
59 skb_reset_network_header(skb);
60 skb_reset_transport_header(skb);
61 skb->protocol = htons(ETH_P_802_2);
62 skb->dev = dev;
63 if (sk != NULL)
64 skb_set_owner_w(skb, sk);
65 }
66 return skb;
67 }
68
69 void llc_save_primitive(struct sock *sk, struct sk_buff *skb, u8 prim)
70 {
71 struct sockaddr_llc *addr;
72
73
74 addr = llc_ui_skb_cb(skb);
75
76 memset(addr, 0, sizeof(*addr));
77 addr->sllc_family = sk->sk_family;
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 }
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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 }
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115
116 static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
117 struct sk_buff *skb)
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
125
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];
130 break;
131 }
132 return rc;
133 }
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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;
149 const llc_sap_action_t *next_action = trans->ev_actions;
150
151 for (; next_action && *next_action; next_action++)
152 if ((*next_action)(sap, skb))
153 rc = 1;
154 return rc;
155 }
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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;
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180
181 rc = llc_exec_sap_trans_actions(sap, trans, skb);
182 if (rc)
183 goto out;
184
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186
187 sap->state = trans->next_state;
188 out:
189 return rc;
190 }
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202
203 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
204 {
205 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
206
207 ev->ind_cfm_flag = 0;
208 llc_sap_next_state(sap, skb);
209
210 if (ev->ind_cfm_flag == LLC_IND && skb->sk->sk_state != TCP_LISTEN) {
211 llc_save_primitive(skb->sk, skb, ev->prim);
212
213
214 if (sock_queue_rcv_skb(skb->sk, skb) == 0)
215 return;
216 }
217 kfree_skb(skb);
218 }
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229
230 void llc_build_and_send_test_pkt(struct llc_sap *sap,
231 struct sk_buff *skb, u8 *dmac, u8 dsap)
232 {
233 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
234
235 ev->saddr.lsap = sap->laddr.lsap;
236 ev->daddr.lsap = dsap;
237 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
238 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
239
240 ev->type = LLC_SAP_EV_TYPE_PRIM;
241 ev->prim = LLC_TEST_PRIM;
242 ev->prim_type = LLC_PRIM_TYPE_REQ;
243 llc_sap_state_process(sap, skb);
244 }
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256 void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
257 u8 *dmac, u8 dsap)
258 {
259 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
260
261 ev->saddr.lsap = sap->laddr.lsap;
262 ev->daddr.lsap = dsap;
263 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
264 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
265
266 ev->type = LLC_SAP_EV_TYPE_PRIM;
267 ev->prim = LLC_XID_PRIM;
268 ev->prim_type = LLC_PRIM_TYPE_REQ;
269 llc_sap_state_process(sap, skb);
270 }
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279 static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
280 struct sock *sk)
281 {
282 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
283
284 ev->type = LLC_SAP_EV_TYPE_PDU;
285 ev->reason = 0;
286 skb_orphan(skb);
287 sock_hold(sk);
288 skb->sk = sk;
289 skb->destructor = sock_efree;
290 llc_sap_state_process(sap, skb);
291 }
292
293 static inline bool llc_dgram_match(const struct llc_sap *sap,
294 const struct llc_addr *laddr,
295 const struct sock *sk)
296 {
297 struct llc_sock *llc = llc_sk(sk);
298
299 return sk->sk_type == SOCK_DGRAM &&
300 llc->laddr.lsap == laddr->lsap &&
301 ether_addr_equal(llc->laddr.mac, laddr->mac);
302 }
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312 static struct sock *llc_lookup_dgram(struct llc_sap *sap,
313 const struct llc_addr *laddr)
314 {
315 struct sock *rc;
316 struct hlist_nulls_node *node;
317 int slot = llc_sk_laddr_hashfn(sap, laddr);
318 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
319
320 rcu_read_lock_bh();
321 again:
322 sk_nulls_for_each_rcu(rc, node, laddr_hb) {
323 if (llc_dgram_match(sap, laddr, rc)) {
324
325 if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
326 goto again;
327 if (unlikely(llc_sk(rc)->sap != sap ||
328 !llc_dgram_match(sap, laddr, rc))) {
329 sock_put(rc);
330 continue;
331 }
332 goto found;
333 }
334 }
335 rc = NULL;
336
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340
341 if (unlikely(get_nulls_value(node) != slot))
342 goto again;
343 found:
344 rcu_read_unlock_bh();
345 return rc;
346 }
347
348 static inline bool llc_mcast_match(const struct llc_sap *sap,
349 const struct llc_addr *laddr,
350 const struct sk_buff *skb,
351 const struct sock *sk)
352 {
353 struct llc_sock *llc = llc_sk(sk);
354
355 return sk->sk_type == SOCK_DGRAM &&
356 llc->laddr.lsap == laddr->lsap &&
357 llc->dev == skb->dev;
358 }
359
360 static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb,
361 struct sock **stack, int count)
362 {
363 struct sk_buff *skb1;
364 int i;
365
366 for (i = 0; i < count; i++) {
367 skb1 = skb_clone(skb, GFP_ATOMIC);
368 if (!skb1) {
369 sock_put(stack[i]);
370 continue;
371 }
372
373 llc_sap_rcv(sap, skb1, stack[i]);
374 sock_put(stack[i]);
375 }
376 }
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386 static void llc_sap_mcast(struct llc_sap *sap,
387 const struct llc_addr *laddr,
388 struct sk_buff *skb)
389 {
390 int i = 0;
391 struct sock *sk;
392 struct sock *stack[256 / sizeof(struct sock *)];
393 struct llc_sock *llc;
394 struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
395
396 spin_lock_bh(&sap->sk_lock);
397 hlist_for_each_entry(llc, dev_hb, dev_hash_node) {
398
399 sk = &llc->sk;
400
401 if (!llc_mcast_match(sap, laddr, skb, sk))
402 continue;
403
404 sock_hold(sk);
405 if (i < ARRAY_SIZE(stack))
406 stack[i++] = sk;
407 else {
408 llc_do_mcast(sap, skb, stack, i);
409 i = 0;
410 }
411 }
412 spin_unlock_bh(&sap->sk_lock);
413
414 llc_do_mcast(sap, skb, stack, i);
415 }
416
417
418 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
419 {
420 struct llc_addr laddr;
421
422 llc_pdu_decode_da(skb, laddr.mac);
423 llc_pdu_decode_dsap(skb, &laddr.lsap);
424
425 if (is_multicast_ether_addr(laddr.mac)) {
426 llc_sap_mcast(sap, &laddr, skb);
427 kfree_skb(skb);
428 } else {
429 struct sock *sk = llc_lookup_dgram(sap, &laddr);
430 if (sk) {
431 llc_sap_rcv(sap, skb, sk);
432 sock_put(sk);
433 } else
434 kfree_skb(skb);
435 }
436 }