]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - net/llc/llc_sap.c
2 * llc_sap.c - driver routines for SAP component.
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
12 * See the GNU General Public License for more details.
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>
24 #include <net/tcp_states.h>
25 #include <linux/llc.h>
26 #include <linux/slab.h>
28 static int llc_mac_header_len(unsigned short devtype
)
33 return sizeof(struct ethhdr
);
39 * llc_alloc_frame - allocates sk_buff for frame
40 * @dev: network device this skb will be sent over
41 * @type: pdu type to allocate
42 * @data_size: data size to allocate
44 * Allocates an sk_buff for frame and initializes sk_buff fields.
45 * Returns allocated skb or %NULL when out of memory.
47 struct sk_buff
*llc_alloc_frame(struct sock
*sk
, struct net_device
*dev
,
48 u8 type
, u32 data_size
)
50 int hlen
= type
== LLC_PDU_TYPE_U
? 3 : 4;
53 hlen
+= llc_mac_header_len(dev
->type
);
54 skb
= alloc_skb(hlen
+ data_size
, GFP_ATOMIC
);
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
);
64 skb_set_owner_w(skb
, sk
);
69 void llc_save_primitive(struct sock
*sk
, struct sk_buff
*skb
, u8 prim
)
71 struct sockaddr_llc
*addr
;
73 /* save primitive for use by the user. */
74 addr
= llc_ui_skb_cb(skb
);
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
);
87 * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
88 * @sap: pointer to SAP
91 void llc_sap_rtn_pdu(struct llc_sap
*sap
, struct sk_buff
*skb
)
93 struct llc_sap_state_ev
*ev
= llc_sap_ev(skb
);
94 struct llc_pdu_un
*pdu
= llc_pdu_un_hdr(skb
);
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;
104 ev
->ind_cfm_flag
= LLC_IND
;
108 * llc_find_sap_trans - finds transition for event
109 * @sap: pointer to SAP
110 * @skb: happened event
112 * This function finds transition that matches with happened event.
113 * Returns the pointer to found transition on success or %NULL for
116 static struct llc_sap_state_trans
*llc_find_sap_trans(struct llc_sap
*sap
,
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];
124 * Search thru events for this state until list exhausted or until
125 * its obvious the event is not valid for the current state
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 */
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.
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.
144 static int llc_exec_sap_trans_actions(struct llc_sap
*sap
,
145 struct llc_sap_state_trans
*trans
,
149 const llc_sap_action_t
*next_action
= trans
->ev_actions
;
151 for (; next_action
&& *next_action
; next_action
++)
152 if ((*next_action
)(sap
, skb
))
158 * llc_sap_next_state - finds transition, execs actions & change SAP state
159 * @sap: pointer to SAP
160 * @skb: happened event
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.
166 static int llc_sap_next_state(struct llc_sap
*sap
, struct sk_buff
*skb
)
169 struct llc_sap_state_trans
*trans
;
171 if (sap
->state
> LLC_NR_SAP_STATES
)
173 trans
= llc_find_sap_trans(sap
, skb
);
177 * Got the state to which we next transition; perform the actions
178 * associated with this transition before actually transitioning to the
181 rc
= llc_exec_sap_trans_actions(sap
, trans
, skb
);
185 * Transition SAP to next state if all actions execute successfully
187 sap
->state
= trans
->next_state
;
193 * llc_sap_state_process - sends event to SAP state machine
195 * @skb: pointer to occurred event
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.
201 * This function always consumes a reference to the skb.
203 static void llc_sap_state_process(struct llc_sap
*sap
, struct sk_buff
*skb
)
205 struct llc_sap_state_ev
*ev
= llc_sap_ev(skb
);
207 ev
->ind_cfm_flag
= 0;
208 llc_sap_next_state(sap
, skb
);
210 if (ev
->ind_cfm_flag
== LLC_IND
&& skb
->sk
->sk_state
!= TCP_LISTEN
) {
211 llc_save_primitive(skb
->sk
, skb
, ev
->prim
);
213 /* queue skb to the user. */
214 if (sock_queue_rcv_skb(skb
->sk
, skb
) == 0)
221 * llc_build_and_send_test_pkt - TEST interface for upper layers.
223 * @skb: packet to send
224 * @dmac: destination mac address
225 * @dsap: destination sap
227 * This function is called when upper layer wants to send a TEST pdu.
228 * Returns 0 for success, 1 otherwise.
230 void llc_build_and_send_test_pkt(struct llc_sap
*sap
,
231 struct sk_buff
*skb
, u8
*dmac
, u8 dsap
)
233 struct llc_sap_state_ev
*ev
= llc_sap_ev(skb
);
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
);
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
);
247 * llc_build_and_send_xid_pkt - XID interface for upper layers
249 * @skb: packet to send
250 * @dmac: destination mac address
251 * @dsap: destination sap
253 * This function is called when upper layer wants to send a XID pdu.
254 * Returns 0 for success, 1 otherwise.
256 void llc_build_and_send_xid_pkt(struct llc_sap
*sap
, struct sk_buff
*skb
,
259 struct llc_sap_state_ev
*ev
= llc_sap_ev(skb
);
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
);
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
);
273 * llc_sap_rcv - sends received pdus to the sap state machine
274 * @sap: current sap component structure.
275 * @skb: received frame.
277 * Sends received pdus to the sap state machine.
279 static void llc_sap_rcv(struct llc_sap
*sap
, struct sk_buff
*skb
,
282 struct llc_sap_state_ev
*ev
= llc_sap_ev(skb
);
284 ev
->type
= LLC_SAP_EV_TYPE_PDU
;
289 skb
->destructor
= sock_efree
;
290 llc_sap_state_process(sap
, skb
);
293 static inline bool llc_dgram_match(const struct llc_sap
*sap
,
294 const struct llc_addr
*laddr
,
295 const struct sock
*sk
)
297 struct llc_sock
*llc
= llc_sk(sk
);
299 return sk
->sk_type
== SOCK_DGRAM
&&
300 llc
->laddr
.lsap
== laddr
->lsap
&&
301 ether_addr_equal(llc
->laddr
.mac
, laddr
->mac
);
305 * llc_lookup_dgram - Finds dgram socket for the local sap/mac
307 * @laddr: address of local LLC (MAC + SAP)
309 * Search socket list of the SAP and finds connection using the local
310 * mac, and local sap. Returns pointer for socket found, %NULL otherwise.
312 static struct sock
*llc_lookup_dgram(struct llc_sap
*sap
,
313 const struct llc_addr
*laddr
)
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
];
322 sk_nulls_for_each_rcu(rc
, node
, laddr_hb
) {
323 if (llc_dgram_match(sap
, laddr
, rc
)) {
324 /* Extra checks required by SLAB_TYPESAFE_BY_RCU */
325 if (unlikely(!refcount_inc_not_zero(&rc
->sk_refcnt
)))
327 if (unlikely(llc_sk(rc
)->sap
!= sap
||
328 !llc_dgram_match(sap
, laddr
, rc
))) {
337 * if the nulls value we got at the end of this lookup is
338 * not the expected one, we must restart lookup.
339 * We probably met an item that was moved to another chain.
341 if (unlikely(get_nulls_value(node
) != slot
))
344 rcu_read_unlock_bh();
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
)
353 struct llc_sock
*llc
= llc_sk(sk
);
355 return sk
->sk_type
== SOCK_DGRAM
&&
356 llc
->laddr
.lsap
== laddr
->lsap
&&
357 llc
->dev
== skb
->dev
;
360 static void llc_do_mcast(struct llc_sap
*sap
, struct sk_buff
*skb
,
361 struct sock
**stack
, int count
)
363 struct sk_buff
*skb1
;
366 for (i
= 0; i
< count
; i
++) {
367 skb1
= skb_clone(skb
, GFP_ATOMIC
);
373 llc_sap_rcv(sap
, skb1
, stack
[i
]);
379 * llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
381 * @laddr: address of local LLC (MAC + SAP)
383 * Search socket list of the SAP and finds connections with same sap.
384 * Deliver clone to each.
386 static void llc_sap_mcast(struct llc_sap
*sap
,
387 const struct llc_addr
*laddr
,
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
);
396 spin_lock_bh(&sap
->sk_lock
);
397 hlist_for_each_entry(llc
, dev_hb
, dev_hash_node
) {
401 if (!llc_mcast_match(sap
, laddr
, skb
, sk
))
405 if (i
< ARRAY_SIZE(stack
))
408 llc_do_mcast(sap
, skb
, stack
, i
);
412 spin_unlock_bh(&sap
->sk_lock
);
414 llc_do_mcast(sap
, skb
, stack
, i
);
418 void llc_sap_handler(struct llc_sap
*sap
, struct sk_buff
*skb
)
420 struct llc_addr laddr
;
422 llc_pdu_decode_da(skb
, laddr
.mac
);
423 llc_pdu_decode_dsap(skb
, &laddr
.lsap
);
425 if (is_multicast_ether_addr(laddr
.mac
)) {
426 llc_sap_mcast(sap
, &laddr
, skb
);
429 struct sock
*sk
= llc_lookup_dgram(sap
, &laddr
);
431 llc_sap_rcv(sap
, skb
, sk
);