[linux.git] / net / llc / llc_sap.c

/*
 * llc_sap.c - driver routines for SAP component.
 *
 * Copyright (c) 1997 by Procom Technology, Inc.
 * 		 2001-2003 by Arnaldo Carvalho de Melo <[email protected]>
 *
 * This program can be redistributed or modified under the terms of the
 * GNU General Public License as published by the Free Software Foundation.
 * This program is distributed without any warranty or implied warranty
 * of merchantability or fitness for a particular purpose.
 *
 * See the GNU General Public License for more details.
 */

#include <net/llc.h>
#include <net/llc_if.h>
#include <net/llc_conn.h>
#include <net/llc_pdu.h>
#include <net/llc_sap.h>
#include <net/llc_s_ac.h>
#include <net/llc_s_ev.h>
#include <net/llc_s_st.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <linux/llc.h>

/**
 *	llc_alloc_frame - allocates sk_buff for frame
 *	@dev: network device this skb will be sent over
 *
 *	Allocates an sk_buff for frame and initializes sk_buff fields.
 *	Returns allocated skb or %NULL when out of memory.
 */
struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev)
{
	struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC);

	if (skb) {
		skb_reserve(skb, 50);
		skb->nh.raw   = skb->h.raw = skb->data;
		skb->protocol = htons(ETH_P_802_2);
		skb->dev      = dev;
		skb->mac.raw  = skb->head;
		if (sk != NULL)
			skb_set_owner_w(skb, sk);
	}
	return skb;
}

void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim)
{
	struct sockaddr_llc *addr;

       /* save primitive for use by the user. */
	addr		  = llc_ui_skb_cb(skb);

	memset(addr, 0, sizeof(*addr));
	addr->sllc_family = sk->sk_family;
	addr->sllc_arphrd = skb->dev->type;
	addr->sllc_test   = prim == LLC_TEST_PRIM;
	addr->sllc_xid    = prim == LLC_XID_PRIM;
	addr->sllc_ua     = prim == LLC_DATAUNIT_PRIM;
	llc_pdu_decode_sa(skb, addr->sllc_mac);
	llc_pdu_decode_ssap(skb, &addr->sllc_sap);
}

/**
 *	llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
 *	@sap: pointer to SAP
 *	@skb: received pdu
 */
void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	switch (LLC_U_PDU_RSP(pdu)) {
	case LLC_1_PDU_CMD_TEST:
		ev->prim = LLC_TEST_PRIM;	break;
	case LLC_1_PDU_CMD_XID:
		ev->prim = LLC_XID_PRIM;	break;
	case LLC_1_PDU_CMD_UI:
		ev->prim = LLC_DATAUNIT_PRIM;	break;
	}
	ev->ind_cfm_flag = LLC_IND;
}

/**
 *	llc_find_sap_trans - finds transition for event
 *	@sap: pointer to SAP
 *	@skb: happened event
 *
 *	This function finds transition that matches with happened event.
 *	Returns the pointer to found transition on success or %NULL for
 *	failure.
 */
static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
						      struct sk_buff* skb)
{
	int i = 0;
	struct llc_sap_state_trans *rc = NULL;
	struct llc_sap_state_trans **next_trans;
	struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
	/*
	 * Search thru events for this state until list exhausted or until
	 * its obvious the event is not valid for the current state
	 */
	for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
		if (!next_trans[i]->ev(sap, skb)) {
			rc = next_trans[i]; /* got event match; return it */
			break;
		}
	return rc;
}

/**
 *	llc_exec_sap_trans_actions - execute actions related to event
 *	@sap: pointer to SAP
 *	@trans: pointer to transition that it's actions must be performed
 *	@skb: happened event.
 *
 *	This function executes actions that is related to happened event.
 *	Returns 0 for success and 1 for failure of at least one action.
 */
static int llc_exec_sap_trans_actions(struct llc_sap *sap,
				      struct llc_sap_state_trans *trans,
				      struct sk_buff *skb)
{
	int rc = 0;
	llc_sap_action_t *next_action = trans->ev_actions;

	for (; next_action && *next_action; next_action++)
		if ((*next_action)(sap, skb))
			rc = 1;
	return rc;
}

/**
 *	llc_sap_next_state - finds transition, execs actions & change SAP state
 *	@sap: pointer to SAP
 *	@skb: happened event
 *
 *	This function finds transition that matches with happened event, then
 *	executes related actions and finally changes state of SAP. It returns
 *	0 on success and 1 for failure.
 */
static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
{
	int rc = 1;
	struct llc_sap_state_trans *trans;

	if (sap->state > LLC_NR_SAP_STATES)
		goto out;
	trans = llc_find_sap_trans(sap, skb);
	if (!trans)
		goto out;
	/*
	 * Got the state to which we next transition; perform the actions
	 * associated with this transition before actually transitioning to the
	 * next state
	 */
	rc = llc_exec_sap_trans_actions(sap, trans, skb);
	if (rc)
		goto out;
	/*
	 * Transition SAP to next state if all actions execute successfully
	 */
	sap->state = trans->next_state;
out:
	return rc;
}

/**
 *	llc_sap_state_process - sends event to SAP state machine
 *	@sap: sap to use
 *	@skb: pointer to occurred event
 *
 *	After executing actions of the event, upper layer will be indicated
 *	if needed(on receiving an UI frame). sk can be null for the
 *	datalink_proto case.
 */
static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);

	/*
	 * We have to hold the skb, because llc_sap_next_state
	 * will kfree it in the sending path and we need to
	 * look at the skb->cb, where we encode llc_sap_state_ev.
	 */
	skb_get(skb);
	ev->ind_cfm_flag = 0;
	llc_sap_next_state(sap, skb);
	if (ev->ind_cfm_flag == LLC_IND) {
		if (skb->sk->sk_state == TCP_LISTEN)
			kfree_skb(skb);
		else {
			llc_save_primitive(skb->sk, skb, ev->prim);

			/* queue skb to the user. */
			if (sock_queue_rcv_skb(skb->sk, skb))
				kfree_skb(skb);
		}
	} 
	kfree_skb(skb);
}

/**
 *	llc_build_and_send_test_pkt - TEST interface for upper layers.
 *	@sap: sap to use
 *	@skb: packet to send
 *	@dmac: destination mac address
 *	@dsap: destination sap
 *
 *	This function is called when upper layer wants to send a TEST pdu.
 *	Returns 0 for success, 1 otherwise.
 */
void llc_build_and_send_test_pkt(struct llc_sap *sap, 
				 struct sk_buff *skb, u8 *dmac, u8 dsap)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);

	ev->saddr.lsap = sap->laddr.lsap;
	ev->daddr.lsap = dsap;
	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
	
	ev->type      = LLC_SAP_EV_TYPE_PRIM;
	ev->prim      = LLC_TEST_PRIM;
	ev->prim_type = LLC_PRIM_TYPE_REQ;
	llc_sap_state_process(sap, skb);
}

/**
 *	llc_build_and_send_xid_pkt - XID interface for upper layers
 *	@sap: sap to use
 *	@skb: packet to send
 *	@dmac: destination mac address
 *	@dsap: destination sap
 *
 *	This function is called when upper layer wants to send a XID pdu.
 *	Returns 0 for success, 1 otherwise.
 */
void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
				u8 *dmac, u8 dsap)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);

	ev->saddr.lsap = sap->laddr.lsap;
	ev->daddr.lsap = dsap;
	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);

	ev->type      = LLC_SAP_EV_TYPE_PRIM;
	ev->prim      = LLC_XID_PRIM;
	ev->prim_type = LLC_PRIM_TYPE_REQ;
	llc_sap_state_process(sap, skb);
}

/**
 *	llc_sap_rcv - sends received pdus to the sap state machine
 *	@sap: current sap component structure.
 *	@skb: received frame.
 *
 *	Sends received pdus to the sap state machine.
 */
static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);

	ev->type   = LLC_SAP_EV_TYPE_PDU;
	ev->reason = 0;
	llc_sap_state_process(sap, skb);
}

/**
 *	llc_lookup_dgram - Finds dgram socket for the local sap/mac
 *	@sap: SAP
 *	@laddr: address of local LLC (MAC + SAP)
 *
 *	Search socket list of the SAP and finds connection using the local
 *	mac, and local sap. Returns pointer for socket found, %NULL otherwise.
 */
static struct sock *llc_lookup_dgram(struct llc_sap *sap,
				     const struct llc_addr *laddr)
{
	struct sock *rc;
	struct hlist_node *node;

	read_lock_bh(&sap->sk_list.lock);
	sk_for_each(rc, node, &sap->sk_list.list) {
		struct llc_sock *llc = llc_sk(rc);

		if (rc->sk_type == SOCK_DGRAM &&
		    llc->laddr.lsap == laddr->lsap &&
		    llc_mac_match(llc->laddr.mac, laddr->mac)) {
			sock_hold(rc);
			goto found;
		}
	}
	rc = NULL;
found:
	read_unlock_bh(&sap->sk_list.lock);
	return rc;
}

/**
 * 	llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
 *	@sap: SAP
 *	@laddr: address of local LLC (MAC + SAP)
 *
 *	Search socket list of the SAP and finds connections with same sap.
 *	Deliver clone to each.
 */
static void llc_sap_mcast(struct llc_sap *sap,
			  const struct llc_addr *laddr,
			  struct sk_buff *skb)
{
	struct sock *sk;
	struct hlist_node *node;

	read_lock_bh(&sap->sk_list.lock);
	sk_for_each(sk, node, &sap->sk_list.list) {
		struct llc_sock *llc = llc_sk(sk);
		struct sk_buff *skb1;

		if (sk->sk_type != SOCK_DGRAM)
			continue;

		if (llc->laddr.lsap != laddr->lsap)
			continue;

		if (llc->dev != skb->dev)
			continue;

		skb1 = skb_clone(skb, GFP_ATOMIC);
		if (!skb1)
			break;

		sock_hold(sk);
		skb_set_owner_r(skb1, sk);
		llc_sap_rcv(sap, skb1);
		sock_put(sk);
	}
	read_unlock_bh(&sap->sk_list.lock);
}


void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
{
	struct llc_addr laddr;

	llc_pdu_decode_da(skb, laddr.mac);
	llc_pdu_decode_dsap(skb, &laddr.lsap);

	if (llc_mac_multicast(laddr.mac)) {
		llc_sap_mcast(sap, &laddr, skb);
		kfree_skb(skb);
	} else {
		struct sock *sk = llc_lookup_dgram(sap, &laddr);
		if (sk) {
			skb_set_owner_r(skb, sk);
			llc_sap_rcv(sap, skb);
			sock_put(sk);
		} else
			kfree_skb(skb);
	}
}
Commit	Line	Data
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 <[email protected]>
	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 LT	25	#include <linux/llc.h>
	26
	27	/**
	28	* llc_alloc_frame - allocates sk_buff for frame
1d67e650	29	* @dev: network device this skb will be sent over
1da177e4 LT	30	*
	31	* Allocates an sk_buff for frame and initializes sk_buff fields.
	32	* Returns allocated skb or %NULL when out of memory.
	33	*/
d389424e	34	struct sk_buff llc_alloc_frame(struct sock sk, struct net_device *dev)
1da177e4 LT	35	{
	36	struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC);
	37
	38	if (skb) {
	39	skb_reserve(skb, 50);
	40	skb->nh.raw = skb->h.raw = skb->data;
	41	skb->protocol = htons(ETH_P_802_2);
1d67e650	42	skb->dev = dev;
1da177e4	43	skb->mac.raw = skb->head;
d389424e ACM	44	if (sk != NULL)
d389424e ACM	45	skb_set_owner_w(skb, sk);
1da177e4 LT	46	}
	47	return skb;
	48	}
	49
04e4223f	50	void llc_save_primitive(struct sock sk, struct sk_buff skb, u8 prim)
1da177e4	51	{
8420e1b5	52	struct sockaddr_llc *addr;
1da177e4 LT	53
1da177e4 LT	54	/* save primitive for use by the user. */
8420e1b5	55	addr = llc_ui_skb_cb(skb);
30a584d9 SH	56
30a584d9 SH	57	memset(addr, 0, sizeof(*addr));
04e4223f	58	addr->sllc_family = sk->sk_family;
1da177e4 LT	59	addr->sllc_arphrd = skb->dev->type;
	60	addr->sllc_test = prim == LLC_TEST_PRIM;
	61	addr->sllc_xid = prim == LLC_XID_PRIM;
	62	addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
	63	llc_pdu_decode_sa(skb, addr->sllc_mac);
	64	llc_pdu_decode_ssap(skb, &addr->sllc_sap);
	65	}
	66
	67	/**
	68	* llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
	69	* @sap: pointer to SAP
	70	* @skb: received pdu
	71	*/
	72	void llc_sap_rtn_pdu(struct llc_sap sap, struct sk_buff skb)
	73	{
	74	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	75	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
	76
	77	switch (LLC_U_PDU_RSP(pdu)) {
	78	case LLC_1_PDU_CMD_TEST:
	79	ev->prim = LLC_TEST_PRIM; break;
	80	case LLC_1_PDU_CMD_XID:
	81	ev->prim = LLC_XID_PRIM; break;
	82	case LLC_1_PDU_CMD_UI:
	83	ev->prim = LLC_DATAUNIT_PRIM; break;
	84	}
	85	ev->ind_cfm_flag = LLC_IND;
	86	}
	87
	88	/**
	89	* llc_find_sap_trans - finds transition for event
	90	* @sap: pointer to SAP
	91	* @skb: happened event
	92	*
	93	* This function finds transition that matches with happened event.
	94	* Returns the pointer to found transition on success or %NULL for
	95	* failure.
	96	*/
	97	static struct llc_sap_state_trans llc_find_sap_trans(struct llc_sap sap,
	98	struct sk_buff* skb)
	99	{
	100	int i = 0;
	101	struct llc_sap_state_trans *rc = NULL;
	102	struct llc_sap_state_trans **next_trans;
	103	struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
	104	/*
	105	* Search thru events for this state until list exhausted or until
	106	* its obvious the event is not valid for the current state
	107	*/
	108	for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
	109	if (!next_trans[i]->ev(sap, skb)) {
	110	rc = next_trans[i]; /* got event match; return it */
	111	break;
	112	}
	113	return rc;
	114	}
	115
	116	/**
	117	* llc_exec_sap_trans_actions - execute actions related to event
	118	* @sap: pointer to SAP
	119	* @trans: pointer to transition that it's actions must be performed
	120	* @skb: happened event.
	121	*
	122	* This function executes actions that is related to happened event.
123	* Returns 0 for success and 1 for failure of at least one action.
124	*/
125	static int llc_exec_sap_trans_actions(struct llc_sap *sap,
126	struct llc_sap_state_trans *trans,
127	struct sk_buff *skb)
128	{
129	int rc = 0;
130	llc_sap_action_t *next_action = trans->ev_actions;
131
132	for (; next_action && *next_action; next_action++)
133	if ((*next_action)(sap, skb))
134	rc = 1;
135	return rc;
136	}
137
138	/**
139	* llc_sap_next_state - finds transition, execs actions & change SAP state
140	* @sap: pointer to SAP
141	* @skb: happened event
142	*
143	* This function finds transition that matches with happened event, then
144	* executes related actions and finally changes state of SAP. It returns
145	* 0 on success and 1 for failure.
146	*/
147	static int llc_sap_next_state(struct llc_sap sap, struct sk_buff skb)
148	{
149	int rc = 1;
150	struct llc_sap_state_trans *trans;
151
152	if (sap->state > LLC_NR_SAP_STATES)
153	goto out;
154	trans = llc_find_sap_trans(sap, skb);
155	if (!trans)
156	goto out;
157	/*
158	* Got the state to which we next transition; perform the actions
159	* associated with this transition before actually transitioning to the
160	* next state
161	*/
162	rc = llc_exec_sap_trans_actions(sap, trans, skb);
163	if (rc)
164	goto out;
165	/*
166	* Transition SAP to next state if all actions execute successfully
167	*/
168	sap->state = trans->next_state;
169	out:
170	return rc;
171	}
172
173	/**
174	* llc_sap_state_process - sends event to SAP state machine
175	* @sap: sap to use
176	* @skb: pointer to occurred event
177	*
178	* After executing actions of the event, upper layer will be indicated
179	* if needed(on receiving an UI frame). sk can be null for the
180	* datalink_proto case.
181	*/
182	static void llc_sap_state_process(struct llc_sap sap, struct sk_buff skb)
183	{
184	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
185
186	/*
187	* We have to hold the skb, because llc_sap_next_state
188	* will kfree it in the sending path and we need to
189	* look at the skb->cb, where we encode llc_sap_state_ev.
190	*/
191	skb_get(skb);
192	ev->ind_cfm_flag = 0;
193	llc_sap_next_state(sap, skb);
194	if (ev->ind_cfm_flag == LLC_IND) {
195	if (skb->sk->sk_state == TCP_LISTEN)
196	kfree_skb(skb);
197	else {
04e4223f	198	llc_save_primitive(skb->sk, skb, ev->prim);
1da177e4 LT	199
	200	/* queue skb to the user. */
	201	if (sock_queue_rcv_skb(skb->sk, skb))
	202	kfree_skb(skb);
	203	}
	204	}
	205	kfree_skb(skb);
	206	}
	207
	208	/**
	209	* llc_build_and_send_test_pkt - TEST interface for upper layers.
	210	* @sap: sap to use
	211	* @skb: packet to send
	212	* @dmac: destination mac address
	213	* @dsap: destination sap
	214	*
	215	* This function is called when upper layer wants to send a TEST pdu.
	216	* Returns 0 for success, 1 otherwise.
	217	*/
	218	void llc_build_and_send_test_pkt(struct llc_sap *sap,
	219	struct sk_buff skb, u8 dmac, u8 dsap)
	220	{
	221	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	222
	223	ev->saddr.lsap = sap->laddr.lsap;
	224	ev->daddr.lsap = dsap;
	225	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	226	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
	227
	228	ev->type = LLC_SAP_EV_TYPE_PRIM;
	229	ev->prim = LLC_TEST_PRIM;
	230	ev->prim_type = LLC_PRIM_TYPE_REQ;
	231	llc_sap_state_process(sap, skb);
	232	}
	233
	234	/**
	235	* llc_build_and_send_xid_pkt - XID interface for upper layers
	236	* @sap: sap to use
	237	* @skb: packet to send
	238	* @dmac: destination mac address
	239	* @dsap: destination sap
	240	*
	241	* This function is called when upper layer wants to send a XID pdu.
	242	* Returns 0 for success, 1 otherwise.
	243	*/
	244	void llc_build_and_send_xid_pkt(struct llc_sap sap, struct sk_buff skb,
	245	u8 *dmac, u8 dsap)
	246	{
	247	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	248
	249	ev->saddr.lsap = sap->laddr.lsap;
	250	ev->daddr.lsap = dsap;
	251	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	252	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
	253
	254	ev->type = LLC_SAP_EV_TYPE_PRIM;
	255	ev->prim = LLC_XID_PRIM;
	256	ev->prim_type = LLC_PRIM_TYPE_REQ;
	257	llc_sap_state_process(sap, skb);
	258	}
	259
	260	/**
	261	* llc_sap_rcv - sends received pdus to the sap state machine
	262	* @sap: current sap component structure.
263	* @skb: received frame.
264	*
265	* Sends received pdus to the sap state machine.
266	*/
267	static void llc_sap_rcv(struct llc_sap sap, struct sk_buff skb)
268	{
269	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
270
271	ev->type = LLC_SAP_EV_TYPE_PDU;
272	ev->reason = 0;
273	llc_sap_state_process(sap, skb);
274	}
275
276	/**
277	* llc_lookup_dgram - Finds dgram socket for the local sap/mac
278	* @sap: SAP
279	* @laddr: address of local LLC (MAC + SAP)
280	*
281	* Search socket list of the SAP and finds connection using the local
282	* mac, and local sap. Returns pointer for socket found, %NULL otherwise.
283	*/
284	static struct sock llc_lookup_dgram(struct llc_sap sap,
bc0e6467	285	const struct llc_addr *laddr)
1da177e4 LT	286	{
	287	struct sock *rc;
	288	struct hlist_node *node;
	289
	290	read_lock_bh(&sap->sk_list.lock);
	291	sk_for_each(rc, node, &sap->sk_list.list) {
	292	struct llc_sock *llc = llc_sk(rc);
	293
	294	if (rc->sk_type == SOCK_DGRAM &&
	295	llc->laddr.lsap == laddr->lsap &&
	296	llc_mac_match(llc->laddr.mac, laddr->mac)) {
	297	sock_hold(rc);
	298	goto found;
	299	}
	300	}
	301	rc = NULL;
	302	found:
	303	read_unlock_bh(&sap->sk_list.lock);
	304	return rc;
	305	}
	306
bc0e6467 SH	307	/**
	308	* llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
	309	* @sap: SAP
	310	* @laddr: address of local LLC (MAC + SAP)
	311	*
	312	* Search socket list of the SAP and finds connections with same sap.
	313	* Deliver clone to each.
	314	*/
	315	static void llc_sap_mcast(struct llc_sap *sap,
	316	const struct llc_addr *laddr,
	317	struct sk_buff *skb)
	318	{
	319	struct sock *sk;
	320	struct hlist_node *node;
	321
	322	read_lock_bh(&sap->sk_list.lock);
	323	sk_for_each(sk, node, &sap->sk_list.list) {
	324	struct llc_sock *llc = llc_sk(sk);
	325	struct sk_buff *skb1;
	326
	327	if (sk->sk_type != SOCK_DGRAM)
	328	continue;
	329
	330	if (llc->laddr.lsap != laddr->lsap)
	331	continue;
	332
7ee66fcb SH	333	if (llc->dev != skb->dev)
	334	continue;
	335
bc0e6467 SH	336	skb1 = skb_clone(skb, GFP_ATOMIC);
	337	if (!skb1)
	338	break;
	339
	340	sock_hold(sk);
	341	skb_set_owner_r(skb1, sk);
	342	llc_sap_rcv(sap, skb1);
	343	sock_put(sk);
	344	}
	345	read_unlock_bh(&sap->sk_list.lock);
	346	}
	347
	348
1da177e4 LT	349	void llc_sap_handler(struct llc_sap sap, struct sk_buff skb)
	350	{
	351	struct llc_addr laddr;
1da177e4 LT	352
	353	llc_pdu_decode_da(skb, laddr.mac);
	354	llc_pdu_decode_dsap(skb, &laddr.lsap);
	355
bc0e6467 SH	356	if (llc_mac_multicast(laddr.mac)) {
bc0e6467 SH	357	llc_sap_mcast(sap, &laddr, skb);
1da177e4	358	kfree_skb(skb);
bc0e6467 SH	359	} else {
	360	struct sock *sk = llc_lookup_dgram(sap, &laddr);
	361	if (sk) {
	362	skb_set_owner_r(skb, sk);
	363	llc_sap_rcv(sap, skb);
	364	sock_put(sk);
	365	} else
	366	kfree_skb(skb);
	367	}
1da177e4	368	}