[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>

static int llc_mac_header_len(unsigned short devtype)
{
	switch (devtype) {
	case ARPHRD_ETHER:
	case ARPHRD_LOOPBACK:
		return sizeof(struct ethhdr);
#ifdef CONFIG_TR
	case ARPHRD_IEEE802_TR:
		return sizeof(struct trh_hdr);
#endif
	}
	return 0;
}

/**
 *	llc_alloc_frame - allocates sk_buff for frame
 *	@dev: network device this skb will be sent over
 *	@type: pdu type to allocate
 *	@data_size: data size to allocate
 *
 *	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,
				u8 type, u32 data_size)
{
	int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
	struct sk_buff *skb;

	hlen += llc_mac_header_len(dev->type);
	skb = alloc_skb(hlen + data_size, GFP_ATOMIC);

	if (skb) {
		skb_reset_mac_header(skb);
		skb_reserve(skb, hlen);
		skb_reset_network_header(skb);
		skb_reset_transport_header(skb);
		skb->protocol = htons(ETH_P_802_2);
		skb->dev      = dev;
		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 sock *sk)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);

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

static inline bool llc_dgram_match(const struct llc_sap *sap,
				   const struct llc_addr *laddr,
				   const struct sock *sk)
{
     struct llc_sock *llc = llc_sk(sk);

     return sk->sk_type == SOCK_DGRAM &&
	  llc->laddr.lsap == laddr->lsap &&
	  llc_mac_match(llc->laddr.mac, laddr->mac);
}

/**
 *	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_nulls_node *node;

	rcu_read_lock_bh();
again:
	sk_nulls_for_each_rcu(rc, node, &sap->sk_list) {
		if (llc_dgram_match(sap, laddr, rc)) {
			/* Extra checks required by SLAB_DESTROY_BY_RCU */
			if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
				goto again;
			if (unlikely(llc_sk(rc)->sap != sap ||
				     !llc_dgram_match(sap, laddr, rc))) {
				sock_put(rc);
				continue;
			}
			goto found;
		}
	}
	rc = NULL;
found:
	rcu_read_unlock_bh();
	return rc;
}

static inline bool llc_mcast_match(const struct llc_sap *sap,
				   const struct llc_addr *laddr,
				   const struct sk_buff *skb,
				   const struct sock *sk)
{
     struct llc_sock *llc = llc_sk(sk);

     return sk->sk_type == SOCK_DGRAM &&
	  llc->laddr.lsap == laddr->lsap &&
	  llc->dev == skb->dev;
}

static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb,
			 struct sock **stack, int count)
{
	struct sk_buff *skb1;
	int i;

	for (i = 0; i < count; i++) {
		skb1 = skb_clone(skb, GFP_ATOMIC);
		if (!skb1) {
			sock_put(stack[i]);
			continue;
		}

		llc_sap_rcv(sap, skb1, stack[i]);
		sock_put(stack[i]);
	}
}

/**
 * 	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)
{
	int i = 0, count = 256 / sizeof(struct sock *);
	struct sock *sk, *stack[count];
	struct hlist_node *node;
	struct llc_sock *llc;
	struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);

	spin_lock_bh(&sap->sk_lock);
	hlist_for_each_entry(llc, node, dev_hb, dev_hash_node) {

		sk = &llc->sk;

		if (!llc_mcast_match(sap, laddr, skb, sk))
			continue;

		sock_hold(sk);
		if (i < count)
			stack[i++] = sk;
		else {
			llc_do_mcast(sap, skb, stack, i);
			i = 0;
		}
	}
	spin_unlock_bh(&sap->sk_lock);

	llc_do_mcast(sap, skb, stack, i);
}


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) {
			llc_sap_rcv(sap, skb, sk);
			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>
1da177e4 LT	26
f83f1768 JP	27	static int llc_mac_header_len(unsigned short devtype)
	28	{
	29	switch (devtype) {
	30	case ARPHRD_ETHER:
	31	case ARPHRD_LOOPBACK:
	32	return sizeof(struct ethhdr);
	33	#ifdef CONFIG_TR
	34	case ARPHRD_IEEE802_TR:
	35	return sizeof(struct trh_hdr);
	36	#endif
	37	}
	38	return 0;
	39	}
	40
1da177e4 LT	41	/**
1da177e4 LT	42	* llc_alloc_frame - allocates sk_buff for frame
1d67e650	43	* @dev: network device this skb will be sent over
f83f1768 JP	44	* @type: pdu type to allocate
f83f1768 JP	45	* @data_size: data size to allocate
1da177e4 LT	46	*
	47	* Allocates an sk_buff for frame and initializes sk_buff fields.
	48	* Returns allocated skb or %NULL when out of memory.
	49	*/
f83f1768 JP	50	struct sk_buff llc_alloc_frame(struct sock sk, struct net_device *dev,
f83f1768 JP	51	u8 type, u32 data_size)
1da177e4	52	{
f83f1768 JP	53	int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
	54	struct sk_buff *skb;
	55
	56	hlen += llc_mac_header_len(dev->type);
	57	skb = alloc_skb(hlen + data_size, GFP_ATOMIC);
1da177e4 LT	58
1da177e4 LT	59	if (skb) {
0a1b0ad9	60	skb_reset_mac_header(skb);
f83f1768	61	skb_reserve(skb, hlen);
c1d2bbe1	62	skb_reset_network_header(skb);
badff6d0	63	skb_reset_transport_header(skb);
1da177e4	64	skb->protocol = htons(ETH_P_802_2);
1d67e650	65	skb->dev = dev;
d389424e ACM	66	if (sk != NULL)
d389424e ACM	67	skb_set_owner_w(skb, sk);
1da177e4 LT	68	}
	69	return skb;
	70	}
	71
04e4223f	72	void llc_save_primitive(struct sock sk, struct sk_buff skb, u8 prim)
1da177e4	73	{
8420e1b5	74	struct sockaddr_llc *addr;
1da177e4 LT	75
1da177e4 LT	76	/* save primitive for use by the user. */
8420e1b5	77	addr = llc_ui_skb_cb(skb);
30a584d9 SH	78
30a584d9 SH	79	memset(addr, 0, sizeof(*addr));
04e4223f	80	addr->sllc_family = sk->sk_family;
1da177e4 LT	81	addr->sllc_arphrd = skb->dev->type;
	82	addr->sllc_test = prim == LLC_TEST_PRIM;
	83	addr->sllc_xid = prim == LLC_XID_PRIM;
	84	addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
	85	llc_pdu_decode_sa(skb, addr->sllc_mac);
	86	llc_pdu_decode_ssap(skb, &addr->sllc_sap);
	87	}
	88
	89	/**
	90	* llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
	91	* @sap: pointer to SAP
	92	* @skb: received pdu
	93	*/
	94	void llc_sap_rtn_pdu(struct llc_sap sap, struct sk_buff skb)
	95	{
	96	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	97	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
	98
	99	switch (LLC_U_PDU_RSP(pdu)) {
	100	case LLC_1_PDU_CMD_TEST:
	101	ev->prim = LLC_TEST_PRIM; break;
	102	case LLC_1_PDU_CMD_XID:
	103	ev->prim = LLC_XID_PRIM; break;
	104	case LLC_1_PDU_CMD_UI:
	105	ev->prim = LLC_DATAUNIT_PRIM; break;
	106	}
	107	ev->ind_cfm_flag = LLC_IND;
	108	}
	109
	110	/**
	111	* llc_find_sap_trans - finds transition for event
	112	* @sap: pointer to SAP
	113	* @skb: happened event
	114	*
	115	* This function finds transition that matches with happened event.
	116	* Returns the pointer to found transition on success or %NULL for
	117	* failure.
	118	*/
	119	static struct llc_sap_state_trans llc_find_sap_trans(struct llc_sap sap,
	120	struct sk_buff* skb)
	121	{
	122	int i = 0;
	123	struct llc_sap_state_trans *rc = NULL;
	124	struct llc_sap_state_trans **next_trans;
	125	struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
	126	/*
	127	* Search thru events for this state until list exhausted or until
	128	* its obvious the event is not valid for the current state
	129	*/
	130	for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
	131	if (!next_trans[i]->ev(sap, skb)) {
	132	rc = next_trans[i]; /* got event match; return it */
	133	break;
	134	}
	135	return rc;
	136	}
	137
	138	/**
	139	* llc_exec_sap_trans_actions - execute actions related to event
	140	* @sap: pointer to SAP
	141	* @trans: pointer to transition that it's actions must be performed
	142	* @skb: happened event.
	143	*
	144	* This function executes actions that is related to happened event.
145	* Returns 0 for success and 1 for failure of at least one action.
146	*/
147	static int llc_exec_sap_trans_actions(struct llc_sap *sap,
148	struct llc_sap_state_trans *trans,
149	struct sk_buff *skb)
150	{
151	int rc = 0;
152	llc_sap_action_t *next_action = trans->ev_actions;
153
154	for (; next_action && *next_action; next_action++)
155	if ((*next_action)(sap, skb))
156	rc = 1;
157	return rc;
158	}
159
160	/**
161	* llc_sap_next_state - finds transition, execs actions & change SAP state
162	* @sap: pointer to SAP
163	* @skb: happened event
164	*
165	* This function finds transition that matches with happened event, then
166	* executes related actions and finally changes state of SAP. It returns
167	* 0 on success and 1 for failure.
168	*/
169	static int llc_sap_next_state(struct llc_sap sap, struct sk_buff skb)
170	{
171	int rc = 1;
172	struct llc_sap_state_trans *trans;
173
174	if (sap->state > LLC_NR_SAP_STATES)
175	goto out;
176	trans = llc_find_sap_trans(sap, skb);
177	if (!trans)
178	goto out;
179	/*
180	* Got the state to which we next transition; perform the actions
181	* associated with this transition before actually transitioning to the
182	* next state
183	*/
184	rc = llc_exec_sap_trans_actions(sap, trans, skb);
185	if (rc)
186	goto out;
187	/*
188	* Transition SAP to next state if all actions execute successfully
189	*/
190	sap->state = trans->next_state;
191	out:
192	return rc;
193	}
194
195	/**
196	* llc_sap_state_process - sends event to SAP state machine
197	* @sap: sap to use
198	* @skb: pointer to occurred event
199	*
200	* After executing actions of the event, upper layer will be indicated
201	* if needed(on receiving an UI frame). sk can be null for the
202	* datalink_proto case.
203	*/
204	static void llc_sap_state_process(struct llc_sap sap, struct sk_buff skb)
205	{
206	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
207
208	/*
209	* We have to hold the skb, because llc_sap_next_state
210	* will kfree it in the sending path and we need to
211	* look at the skb->cb, where we encode llc_sap_state_ev.
212	*/
213	skb_get(skb);
214	ev->ind_cfm_flag = 0;
215	llc_sap_next_state(sap, skb);
216	if (ev->ind_cfm_flag == LLC_IND) {
217	if (skb->sk->sk_state == TCP_LISTEN)
218	kfree_skb(skb);
219	else {
04e4223f	220	llc_save_primitive(skb->sk, skb, ev->prim);
1da177e4 LT	221
	222	/* queue skb to the user. */
	223	if (sock_queue_rcv_skb(skb->sk, skb))
	224	kfree_skb(skb);
	225	}
d57b1869	226	}
1da177e4 LT	227	kfree_skb(skb);
	228	}
	229
	230	/**
	231	* llc_build_and_send_test_pkt - TEST interface for upper layers.
	232	* @sap: sap to use
	233	* @skb: packet to send
	234	* @dmac: destination mac address
	235	* @dsap: destination sap
	236	*
	237	* This function is called when upper layer wants to send a TEST pdu.
	238	* Returns 0 for success, 1 otherwise.
	239	*/
d57b1869	240	void llc_build_and_send_test_pkt(struct llc_sap *sap,
1da177e4 LT	241	struct sk_buff skb, u8 dmac, u8 dsap)
	242	{
	243	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	244
	245	ev->saddr.lsap = sap->laddr.lsap;
	246	ev->daddr.lsap = dsap;
	247	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	248	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
d57b1869	249
1da177e4 LT	250	ev->type = LLC_SAP_EV_TYPE_PRIM;
	251	ev->prim = LLC_TEST_PRIM;
	252	ev->prim_type = LLC_PRIM_TYPE_REQ;
	253	llc_sap_state_process(sap, skb);
	254	}
	255
	256	/**
	257	* llc_build_and_send_xid_pkt - XID interface for upper layers
	258	* @sap: sap to use
	259	* @skb: packet to send
	260	* @dmac: destination mac address
	261	* @dsap: destination sap
	262	*
	263	* This function is called when upper layer wants to send a XID pdu.
	264	* Returns 0 for success, 1 otherwise.
	265	*/
	266	void llc_build_and_send_xid_pkt(struct llc_sap sap, struct sk_buff skb,
	267	u8 *dmac, u8 dsap)
	268	{
	269	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	270
	271	ev->saddr.lsap = sap->laddr.lsap;
	272	ev->daddr.lsap = dsap;
	273	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	274	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
	275
	276	ev->type = LLC_SAP_EV_TYPE_PRIM;
	277	ev->prim = LLC_XID_PRIM;
	278	ev->prim_type = LLC_PRIM_TYPE_REQ;
	279	llc_sap_state_process(sap, skb);
	280	}
	281
	282	/**
	283	* llc_sap_rcv - sends received pdus to the sap state machine
	284	* @sap: current sap component structure.
	285	* @skb: received frame.
	286	*
	287	* Sends received pdus to the sap state machine.
	288	*/
3446b9d5 ACM	289	static void llc_sap_rcv(struct llc_sap sap, struct sk_buff skb,
3446b9d5 ACM	290	struct sock *sk)
1da177e4 LT	291	{
	292	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	293
	294	ev->type = LLC_SAP_EV_TYPE_PDU;
	295	ev->reason = 0;
3446b9d5	296	skb->sk = sk;
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 &&
	308	llc_mac_match(llc->laddr.mac, laddr->mac);
	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	{
1da177e4 LT	322	struct sock *rc;
b76f5a84 OP	323	struct hlist_nulls_node *node;
	324
	325	rcu_read_lock_bh();
	326	again:
	327	sk_nulls_for_each_rcu(rc, node, &sap->sk_list) {
	328	if (llc_dgram_match(sap, laddr, rc)) {
	329	/* Extra checks required by SLAB_DESTROY_BY_RCU */
	330	if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
	331	goto again;
	332	if (unlikely(llc_sk(rc)->sap != sap \|\|
	333	!llc_dgram_match(sap, laddr, rc))) {
	334	sock_put(rc);
	335	continue;
	336	}
1da177e4 LT	337	goto found;
	338	}
	339	}
	340	rc = NULL;
	341	found:
b76f5a84	342	rcu_read_unlock_bh();
1da177e4 LT	343	return rc;
	344	}
	345
b76f5a84 OP	346	static inline bool llc_mcast_match(const struct llc_sap *sap,
	347	const struct llc_addr *laddr,
	348	const struct sk_buff *skb,
	349	const struct sock *sk)
	350	{
	351	struct llc_sock *llc = llc_sk(sk);
	352
	353	return sk->sk_type == SOCK_DGRAM &&
	354	llc->laddr.lsap == laddr->lsap &&
	355	llc->dev == skb->dev;
	356	}
	357
0f7b67dd OP	358	static void llc_do_mcast(struct llc_sap sap, struct sk_buff skb,
	359	struct sock **stack, int count)
	360	{
	361	struct sk_buff *skb1;
	362	int i;
	363
	364	for (i = 0; i < count; i++) {
	365	skb1 = skb_clone(skb, GFP_ATOMIC);
	366	if (!skb1) {
	367	sock_put(stack[i]);
	368	continue;
	369	}
	370
	371	llc_sap_rcv(sap, skb1, stack[i]);
	372	sock_put(stack[i]);
	373	}
	374	}
	375
bc0e6467 SH	376	/**
	377	* llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
	378	* @sap: SAP
	379	* @laddr: address of local LLC (MAC + SAP)
	380	*
	381	* Search socket list of the SAP and finds connections with same sap.
	382	* Deliver clone to each.
	383	*/
	384	static void llc_sap_mcast(struct llc_sap *sap,
	385	const struct llc_addr *laddr,
	386	struct sk_buff *skb)
	387	{
0f7b67dd OP	388	int i = 0, count = 256 / sizeof(struct sock *);
0f7b67dd OP	389	struct sock sk, stack[count];
6d2e3ea2 OP	390	struct hlist_node *node;
	391	struct llc_sock *llc;
	392	struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
bc0e6467	393
b76f5a84	394	spin_lock_bh(&sap->sk_lock);
6d2e3ea2 OP	395	hlist_for_each_entry(llc, node, dev_hb, dev_hash_node) {
	396
	397	sk = &llc->sk;
bc0e6467	398
b76f5a84	399	if (!llc_mcast_match(sap, laddr, skb, sk))
7ee66fcb SH	400	continue;
7ee66fcb SH	401
bc0e6467	402	sock_hold(sk);
0f7b67dd OP	403	if (i < count)
	404	stack[i++] = sk;
	405	else {
	406	llc_do_mcast(sap, skb, stack, i);
	407	i = 0;
	408	}
bc0e6467	409	}
b76f5a84	410	spin_unlock_bh(&sap->sk_lock);
0f7b67dd OP	411
0f7b67dd OP	412	llc_do_mcast(sap, skb, stack, i);
bc0e6467 SH	413	}
	414
	415
1da177e4 LT	416	void llc_sap_handler(struct llc_sap sap, struct sk_buff skb)
	417	{
	418	struct llc_addr laddr;
1da177e4 LT	419
	420	llc_pdu_decode_da(skb, laddr.mac);
	421	llc_pdu_decode_dsap(skb, &laddr.lsap);
	422
bc0e6467 SH	423	if (llc_mac_multicast(laddr.mac)) {
bc0e6467 SH	424	llc_sap_mcast(sap, &laddr, skb);
1da177e4	425	kfree_skb(skb);
bc0e6467 SH	426	} else {
	427	struct sock *sk = llc_lookup_dgram(sap, &laddr);
	428	if (sk) {
3446b9d5	429	llc_sap_rcv(sap, skb, sk);
bc0e6467 SH	430	sock_put(sk);
	431	} else
	432	kfree_skb(skb);
	433	}
1da177e4	434	}