[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>
#include <linux/slab.h>

static int llc_mac_header_len(unsigned short devtype)
{
	switch (devtype) {
	case ARPHRD_ETHER:
	case ARPHRD_LOOPBACK:
		return sizeof(struct ethhdr);
#if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
	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;
	int slot = llc_sk_laddr_hashfn(sap, laddr);
	struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];

	rcu_read_lock_bh();
again:
	sk_nulls_for_each_rcu(rc, node, laddr_hb) {
		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;
	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
	if (unlikely(get_nulls_value(node) != slot))
		goto again;
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	25	#include <linux/llc.h>
5a0e3ad6	26	#include <linux/slab.h>
1da177e4	27
f83f1768 JP	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);
f0ecde14	34	#if defined(CONFIG_TR) \|\| defined(CONFIG_TR_MODULE)
f83f1768 JP	35	case ARPHRD_IEEE802_TR:
	36	return sizeof(struct trh_hdr);
	37	#endif
	38	}
	39	return 0;
	40	}
	41
1da177e4 LT	42	/**
1da177e4 LT	43	* llc_alloc_frame - allocates sk_buff for frame
1d67e650	44	* @dev: network device this skb will be sent over
f83f1768 JP	45	* @type: pdu type to allocate
f83f1768 JP	46	* @data_size: data size to allocate
1da177e4 LT	47	*
	48	* Allocates an sk_buff for frame and initializes sk_buff fields.
	49	* Returns allocated skb or %NULL when out of memory.
	50	*/
f83f1768 JP	51	struct sk_buff llc_alloc_frame(struct sock sk, struct net_device *dev,
f83f1768 JP	52	u8 type, u32 data_size)
1da177e4	53	{
f83f1768 JP	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);
1da177e4 LT	59
1da177e4 LT	60	if (skb) {
0a1b0ad9	61	skb_reset_mac_header(skb);
f83f1768	62	skb_reserve(skb, hlen);
c1d2bbe1	63	skb_reset_network_header(skb);
badff6d0	64	skb_reset_transport_header(skb);
1da177e4	65	skb->protocol = htons(ETH_P_802_2);
1d67e650	66	skb->dev = dev;
d389424e ACM	67	if (sk != NULL)
d389424e ACM	68	skb_set_owner_w(skb, sk);
1da177e4 LT	69	}
	70	return skb;
	71	}
	72
04e4223f	73	void llc_save_primitive(struct sock sk, struct sk_buff skb, u8 prim)
1da177e4	74	{
8420e1b5	75	struct sockaddr_llc *addr;
1da177e4 LT	76
1da177e4 LT	77	/* save primitive for use by the user. */
8420e1b5	78	addr = llc_ui_skb_cb(skb);
30a584d9 SH	79
30a584d9 SH	80	memset(addr, 0, sizeof(*addr));
04e4223f	81	addr->sllc_family = sk->sk_family;
1da177e4 LT	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
	90	/**
	91	* llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
	92	* @sap: pointer to SAP
	93	* @skb: received pdu
	94	*/
	95	void 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
	111	/**
	112	* llc_find_sap_trans - finds transition for event
	113	* @sap: pointer to SAP
	114	* @skb: happened event
	115	*
	116	* This function finds transition that matches with happened event.
	117	* Returns the pointer to found transition on success or %NULL for
	118	* failure.
	119	*/
	120	static 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	* Search thru events for this state until list exhausted or until
	129	* its obvious the event is not valid for the current state
	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]; /* got event match; return it */
	134	break;
	135	}
	136	return rc;
	137	}
	138
	139	/**
	140	* llc_exec_sap_trans_actions - execute actions related to event
	141	* @sap: pointer to SAP
	142	* @trans: pointer to transition that it's actions must be performed
	143	* @skb: happened event.
	144	*
	145	* This function executes actions that is related to happened event.
146	* Returns 0 for success and 1 for failure of at least one action.
147	*/
148	static 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	}
160
161	/**
162	* llc_sap_next_state - finds transition, execs actions & change SAP state
163	* @sap: pointer to SAP
164	* @skb: happened event
165	*
166	* This function finds transition that matches with happened event, then
167	* executes related actions and finally changes state of SAP. It returns
168	* 0 on success and 1 for failure.
169	*/
170	static 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	/*
181	* Got the state to which we next transition; perform the actions
182	* associated with this transition before actually transitioning to the
183	* next state
184	*/
185	rc = llc_exec_sap_trans_actions(sap, trans, skb);
186	if (rc)
187	goto out;
188	/*
189	* Transition SAP to next state if all actions execute successfully
190	*/
191	sap->state = trans->next_state;
192	out:
193	return rc;
194	}
195
196	/**
197	* llc_sap_state_process - sends event to SAP state machine
198	* @sap: sap to use
199	* @skb: pointer to occurred event
200	*
201	* After executing actions of the event, upper layer will be indicated
202	* if needed(on receiving an UI frame). sk can be null for the
203	* datalink_proto case.
204	*/
205	static 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
209	/*
210	* We have to hold the skb, because llc_sap_next_state
211	* will kfree it in the sending path and we need to
212	* look at the skb->cb, where we encode llc_sap_state_ev.
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 {
04e4223f	221	llc_save_primitive(skb->sk, skb, ev->prim);
1da177e4 LT	222
	223	/* queue skb to the user. */
	224	if (sock_queue_rcv_skb(skb->sk, skb))
	225	kfree_skb(skb);
	226	}
d57b1869	227	}
1da177e4 LT	228	kfree_skb(skb);
	229	}
	230
	231	/**
	232	* llc_build_and_send_test_pkt - TEST interface for upper layers.
	233	* @sap: sap to use
	234	* @skb: packet to send
	235	* @dmac: destination mac address
	236	* @dsap: destination sap
	237	*
	238	* This function is called when upper layer wants to send a TEST pdu.
	239	* Returns 0 for success, 1 otherwise.
	240	*/
d57b1869	241	void llc_build_and_send_test_pkt(struct llc_sap *sap,
1da177e4 LT	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);
d57b1869	250
1da177e4 LT	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	}
	256
	257	/**
	258	* llc_build_and_send_xid_pkt - XID interface for upper layers
	259	* @sap: sap to use
	260	* @skb: packet to send
	261	* @dmac: destination mac address
	262	* @dsap: destination sap
	263	*
	264	* This function is called when upper layer wants to send a XID pdu.
	265	* Returns 0 for success, 1 otherwise.
	266	*/
	267	void 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	}
	282
	283	/**
	284	* llc_sap_rcv - sends received pdus to the sap state machine
	285	* @sap: current sap component structure.
	286	* @skb: received frame.
	287	*
	288	* Sends received pdus to the sap state machine.
	289	*/
3446b9d5 ACM	290	static void llc_sap_rcv(struct llc_sap sap, struct sk_buff skb,
3446b9d5 ACM	291	struct sock *sk)
1da177e4 LT	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;
3446b9d5	297	skb->sk = sk;
1da177e4 LT	298	llc_sap_state_process(sap, skb);
	299	}
	300
b76f5a84 OP	301	static 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	}
	311
1da177e4 LT	312	/**
	313	* llc_lookup_dgram - Finds dgram socket for the local sap/mac
	314	* @sap: SAP
	315	* @laddr: address of local LLC (MAC + SAP)
	316	*
	317	* Search socket list of the SAP and finds connection using the local
	318	* mac, and local sap. Returns pointer for socket found, %NULL otherwise.
	319	*/
	320	static struct sock llc_lookup_dgram(struct llc_sap sap,
bc0e6467	321	const struct llc_addr *laddr)
1da177e4 LT	322	{
1da177e4 LT	323	struct sock *rc;
b76f5a84	324	struct hlist_nulls_node *node;
52d58aef OP	325	int slot = llc_sk_laddr_hashfn(sap, laddr);
52d58aef OP	326	struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
b76f5a84 OP	327
	328	rcu_read_lock_bh();
	329	again:
52d58aef	330	sk_nulls_for_each_rcu(rc, node, laddr_hb) {
b76f5a84 OP	331	if (llc_dgram_match(sap, laddr, rc)) {
	332	/* Extra checks required by SLAB_DESTROY_BY_RCU */
	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	}
1da177e4 LT	340	goto found;
	341	}
	342	}
	343	rc = NULL;
52d58aef OP	344	/*
	345	* if the nulls value we got at the end of this lookup is
	346	* not the expected one, we must restart lookup.
	347	* We probably met an item that was moved to another chain.
	348	*/
	349	if (unlikely(get_nulls_value(node) != slot))
	350	goto again;
1da177e4	351	found:
b76f5a84	352	rcu_read_unlock_bh();
1da177e4 LT	353	return rc;
	354	}
	355
b76f5a84 OP	356	static 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
0f7b67dd OP	368	static 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
bc0e6467 SH	386	/**
	387	* llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
	388	* @sap: SAP
	389	* @laddr: address of local LLC (MAC + SAP)
	390	*
	391	* Search socket list of the SAP and finds connections with same sap.
	392	* Deliver clone to each.
	393	*/
	394	static void llc_sap_mcast(struct llc_sap *sap,
	395	const struct llc_addr *laddr,
	396	struct sk_buff *skb)
	397	{
0f7b67dd OP	398	int i = 0, count = 256 / sizeof(struct sock *);
0f7b67dd OP	399	struct sock sk, stack[count];
6d2e3ea2 OP	400	struct hlist_node *node;
	401	struct llc_sock *llc;
	402	struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
bc0e6467	403
b76f5a84	404	spin_lock_bh(&sap->sk_lock);
6d2e3ea2 OP	405	hlist_for_each_entry(llc, node, dev_hb, dev_hash_node) {
	406
	407	sk = &llc->sk;
bc0e6467	408
b76f5a84	409	if (!llc_mcast_match(sap, laddr, skb, sk))
7ee66fcb SH	410	continue;
7ee66fcb SH	411
bc0e6467	412	sock_hold(sk);
0f7b67dd OP	413	if (i < count)
	414	stack[i++] = sk;
	415	else {
	416	llc_do_mcast(sap, skb, stack, i);
	417	i = 0;
	418	}
bc0e6467	419	}
b76f5a84	420	spin_unlock_bh(&sap->sk_lock);
0f7b67dd OP	421
0f7b67dd OP	422	llc_do_mcast(sap, skb, stack, i);
bc0e6467 SH	423	}
	424
	425
1da177e4 LT	426	void llc_sap_handler(struct llc_sap sap, struct sk_buff skb)
	427	{
	428	struct llc_addr laddr;
1da177e4 LT	429
	430	llc_pdu_decode_da(skb, laddr.mac);
	431	llc_pdu_decode_dsap(skb, &laddr.lsap);
	432
bc0e6467 SH	433	if (llc_mac_multicast(laddr.mac)) {
bc0e6467 SH	434	llc_sap_mcast(sap, &laddr, skb);
1da177e4	435	kfree_skb(skb);
bc0e6467 SH	436	} else {
	437	struct sock *sk = llc_lookup_dgram(sap, &laddr);
	438	if (sk) {
3446b9d5	439	llc_sap_rcv(sap, skb, sk);
bc0e6467 SH	440	sock_put(sk);
	441	} else
	442	kfree_skb(skb);
	443	}
1da177e4	444	}