[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);
	}
	return 0;
}

/**
 *	llc_alloc_frame - allocates sk_buff for frame
 *	@sk:  socket to allocate frame to
 *	@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;
	const 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.
 *
 *	This function always consumes a reference to the skb.
 */
static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
{
	struct llc_sap_state_ev *ev = llc_sap_ev(skb);

	ev->ind_cfm_flag = 0;
	llc_sap_next_state(sap, skb);

	if (ev->ind_cfm_flag == LLC_IND && skb->sk->sk_state != TCP_LISTEN) {
		llc_save_primitive(skb->sk, skb, ev->prim);

		/* queue skb to the user. */
		if (sock_queue_rcv_skb(skb->sk, skb) == 0)
			return;
	}
	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.
 *	@sk:  socket to associate to 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_orphan(skb);
	sock_hold(sk);
	skb->sk = sk;
	skb->destructor = sock_efree;
	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,
				   const struct net *net)
{
     struct llc_sock *llc = llc_sk(sk);

     return sk->sk_type == SOCK_DGRAM &&
	     net_eq(sock_net(sk), net) &&
	     llc->laddr.lsap == laddr->lsap &&
	     ether_addr_equal(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)
 *	@net: netns to look up a socket in
 *
 *	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,
				     const struct net *net)
{
	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, net)) {
			/* Extra checks required by SLAB_TYPESAFE_BY_RCU */
			if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
				goto again;
			if (unlikely(llc_sk(rc)->sap != sap ||
				     !llc_dgram_match(sap, laddr, rc, net))) {
				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)
 *	@skb: PDU to deliver
 *
 *	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;
	struct sock *sk;
	struct sock *stack[256 / sizeof(struct sock *)];
	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, dev_hb, dev_hash_node) {

		sk = &llc->sk;

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

		sock_hold(sk);
		if (i < ARRAY_SIZE(stack))
			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 (is_multicast_ether_addr(laddr.mac)) {
		llc_sap_mcast(sap, &laddr, skb);
		kfree_skb(skb);
	} else {
		struct sock *sk = llc_lookup_dgram(sap, &laddr, dev_net(skb->dev));
		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);
f83f1768 JP	34	}
	35	return 0;
	36	}
	37
1da177e4 LT	38	/**
1da177e4 LT	39	* llc_alloc_frame - allocates sk_buff for frame
74c950c9	40	* @sk: socket to allocate frame to
1d67e650	41	* @dev: network device this skb will be sent over
f83f1768 JP	42	* @type: pdu type to allocate
f83f1768 JP	43	* @data_size: data size to allocate
1da177e4 LT	44	*
	45	* Allocates an sk_buff for frame and initializes sk_buff fields.
	46	* Returns allocated skb or %NULL when out of memory.
	47	*/
f83f1768 JP	48	struct sk_buff llc_alloc_frame(struct sock sk, struct net_device *dev,
f83f1768 JP	49	u8 type, u32 data_size)
1da177e4	50	{
f83f1768 JP	51	int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
	52	struct sk_buff *skb;
	53
	54	hlen += llc_mac_header_len(dev->type);
	55	skb = alloc_skb(hlen + data_size, GFP_ATOMIC);
1da177e4 LT	56
1da177e4 LT	57	if (skb) {
0a1b0ad9	58	skb_reset_mac_header(skb);
f83f1768	59	skb_reserve(skb, hlen);
c1d2bbe1	60	skb_reset_network_header(skb);
badff6d0	61	skb_reset_transport_header(skb);
1da177e4	62	skb->protocol = htons(ETH_P_802_2);
1d67e650	63	skb->dev = dev;
d389424e ACM	64	if (sk != NULL)
d389424e ACM	65	skb_set_owner_w(skb, sk);
1da177e4 LT	66	}
	67	return skb;
	68	}
	69
3cdba604	70	void llc_save_primitive(struct sock sk, struct sk_buff skb, u8 prim)
1da177e4	71	{
8420e1b5	72	struct sockaddr_llc *addr;
1da177e4 LT	73
1da177e4 LT	74	/* save primitive for use by the user. */
8420e1b5	75	addr = llc_ui_skb_cb(skb);
30a584d9 SH	76
30a584d9 SH	77	memset(addr, 0, sizeof(*addr));
04e4223f	78	addr->sllc_family = sk->sk_family;
1da177e4 LT	79	addr->sllc_arphrd = skb->dev->type;
	80	addr->sllc_test = prim == LLC_TEST_PRIM;
	81	addr->sllc_xid = prim == LLC_XID_PRIM;
	82	addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
	83	llc_pdu_decode_sa(skb, addr->sllc_mac);
	84	llc_pdu_decode_ssap(skb, &addr->sllc_sap);
	85	}
	86
	87	/**
	88	* llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
	89	* @sap: pointer to SAP
	90	* @skb: received pdu
	91	*/
	92	void llc_sap_rtn_pdu(struct llc_sap sap, struct sk_buff skb)
	93	{
	94	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	95	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
	96
	97	switch (LLC_U_PDU_RSP(pdu)) {
	98	case LLC_1_PDU_CMD_TEST:
	99	ev->prim = LLC_TEST_PRIM; break;
	100	case LLC_1_PDU_CMD_XID:
	101	ev->prim = LLC_XID_PRIM; break;
	102	case LLC_1_PDU_CMD_UI:
	103	ev->prim = LLC_DATAUNIT_PRIM; break;
	104	}
	105	ev->ind_cfm_flag = LLC_IND;
	106	}
	107
	108	/**
	109	* llc_find_sap_trans - finds transition for event
	110	* @sap: pointer to SAP
	111	* @skb: happened event
	112	*
	113	* This function finds transition that matches with happened event.
	114	* Returns the pointer to found transition on success or %NULL for
	115	* failure.
	116	*/
	117	static struct llc_sap_state_trans llc_find_sap_trans(struct llc_sap sap,
3cdba604	118	struct sk_buff *skb)
1da177e4 LT	119	{
	120	int i = 0;
	121	struct llc_sap_state_trans *rc = NULL;
	122	struct llc_sap_state_trans **next_trans;
	123	struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
	124	/*
	125	* Search thru events for this state until list exhausted or until
	126	* its obvious the event is not valid for the current state
	127	*/
	128	for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
	129	if (!next_trans[i]->ev(sap, skb)) {
	130	rc = next_trans[i]; /* got event match; return it */
	131	break;
	132	}
	133	return rc;
	134	}
	135
	136	/**
	137	* llc_exec_sap_trans_actions - execute actions related to event
	138	* @sap: pointer to SAP
	139	* @trans: pointer to transition that it's actions must be performed
	140	* @skb: happened event.
	141	*
	142	* This function executes actions that is related to happened event.
	143	* Returns 0 for success and 1 for failure of at least one action.
	144	*/
	145	static int llc_exec_sap_trans_actions(struct llc_sap *sap,
	146	struct llc_sap_state_trans *trans,
	147	struct sk_buff *skb)
	148	{
	149	int rc = 0;
22bbf5f3	150	const llc_sap_action_t *next_action = trans->ev_actions;
1da177e4 LT	151
	152	for (; next_action && *next_action; next_action++)
	153	if ((*next_action)(sap, skb))
	154	rc = 1;
	155	return rc;
	156	}
	157
	158	/**
	159	* llc_sap_next_state - finds transition, execs actions & change SAP state
	160	* @sap: pointer to SAP
	161	* @skb: happened event
	162	*
	163	* This function finds transition that matches with happened event, then
	164	* executes related actions and finally changes state of SAP. It returns
	165	* 0 on success and 1 for failure.
	166	*/
	167	static int llc_sap_next_state(struct llc_sap sap, struct sk_buff skb)
	168	{
	169	int rc = 1;
	170	struct llc_sap_state_trans *trans;
	171
	172	if (sap->state > LLC_NR_SAP_STATES)
	173	goto out;
	174	trans = llc_find_sap_trans(sap, skb);
	175	if (!trans)
	176	goto out;
	177	/*
	178	* Got the state to which we next transition; perform the actions
	179	* associated with this transition before actually transitioning to the
	180	* next state
	181	*/
	182	rc = llc_exec_sap_trans_actions(sap, trans, skb);
	183	if (rc)
	184	goto out;
	185	/*
	186	* Transition SAP to next state if all actions execute successfully
	187	*/
	188	sap->state = trans->next_state;
	189	out:
	190	return rc;
	191	}
	192
	193	/**
	194	* llc_sap_state_process - sends event to SAP state machine
	195	* @sap: sap to use
	196	* @skb: pointer to occurred event
	197	*
	198	* After executing actions of the event, upper layer will be indicated
	199	* if needed(on receiving an UI frame). sk can be null for the
	200	* datalink_proto case.
c6ee11c3 EB	201	*
c6ee11c3 EB	202	* This function always consumes a reference to the skb.
1da177e4 LT	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
1da177e4 LT	208	ev->ind_cfm_flag = 0;
1da177e4 LT	209	llc_sap_next_state(sap, skb);
c6ee11c3 EB	210
	211	if (ev->ind_cfm_flag == LLC_IND && skb->sk->sk_state != TCP_LISTEN) {
	212	llc_save_primitive(skb->sk, skb, ev->prim);
	213
	214	/* queue skb to the user. */
	215	if (sock_queue_rcv_skb(skb->sk, skb) == 0)
	216	return;
d57b1869	217	}
1da177e4 LT	218	kfree_skb(skb);
	219	}
	220
	221	/**
	222	* llc_build_and_send_test_pkt - TEST interface for upper layers.
	223	* @sap: sap to use
	224	* @skb: packet to send
	225	* @dmac: destination mac address
	226	* @dsap: destination sap
	227	*
	228	* This function is called when upper layer wants to send a TEST pdu.
	229	* Returns 0 for success, 1 otherwise.
	230	*/
d57b1869	231	void llc_build_and_send_test_pkt(struct llc_sap *sap,
1da177e4 LT	232	struct sk_buff skb, u8 dmac, u8 dsap)
	233	{
	234	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	235
	236	ev->saddr.lsap = sap->laddr.lsap;
	237	ev->daddr.lsap = dsap;
	238	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	239	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
d57b1869	240
1da177e4 LT	241	ev->type = LLC_SAP_EV_TYPE_PRIM;
	242	ev->prim = LLC_TEST_PRIM;
	243	ev->prim_type = LLC_PRIM_TYPE_REQ;
	244	llc_sap_state_process(sap, skb);
	245	}
	246
	247	/**
	248	* llc_build_and_send_xid_pkt - XID interface for upper layers
	249	* @sap: sap to use
	250	* @skb: packet to send
	251	* @dmac: destination mac address
	252	* @dsap: destination sap
	253	*
	254	* This function is called when upper layer wants to send a XID pdu.
	255	* Returns 0 for success, 1 otherwise.
	256	*/
	257	void llc_build_and_send_xid_pkt(struct llc_sap sap, struct sk_buff skb,
	258	u8 *dmac, u8 dsap)
	259	{
	260	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	261
	262	ev->saddr.lsap = sap->laddr.lsap;
	263	ev->daddr.lsap = dsap;
	264	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	265	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
	266
	267	ev->type = LLC_SAP_EV_TYPE_PRIM;
	268	ev->prim = LLC_XID_PRIM;
	269	ev->prim_type = LLC_PRIM_TYPE_REQ;
	270	llc_sap_state_process(sap, skb);
	271	}
	272
	273	/**
	274	* llc_sap_rcv - sends received pdus to the sap state machine
	275	* @sap: current sap component structure.
	276	* @skb: received frame.
74c950c9	277	* @sk: socket to associate to frame
1da177e4 LT	278	*
	279	* Sends received pdus to the sap state machine.
	280	*/
3446b9d5 ACM	281	static void llc_sap_rcv(struct llc_sap sap, struct sk_buff skb,
3446b9d5 ACM	282	struct sock *sk)
1da177e4 LT	283	{
	284	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	285
	286	ev->type = LLC_SAP_EV_TYPE_PDU;
	287	ev->reason = 0;
8b74d439 ED	288	skb_orphan(skb);
8b74d439 ED	289	sock_hold(sk);
3446b9d5	290	skb->sk = sk;
8b74d439	291	skb->destructor = sock_efree;
1da177e4 LT	292	llc_sap_state_process(sap, skb);
	293	}
	294
b76f5a84 OP	295	static inline bool llc_dgram_match(const struct llc_sap *sap,
b76f5a84 OP	296	const struct llc_addr *laddr,
9b64e93e KI	297	const struct sock *sk,
9b64e93e KI	298	const struct net *net)
b76f5a84 OP	299	{
	300	struct llc_sock *llc = llc_sk(sk);
	301
	302	return sk->sk_type == SOCK_DGRAM &&
9b64e93e KI	303	net_eq(sock_net(sk), net) &&
	304	llc->laddr.lsap == laddr->lsap &&
	305	ether_addr_equal(llc->laddr.mac, laddr->mac);
b76f5a84 OP	306	}
b76f5a84 OP	307
1da177e4 LT	308	/**
	309	* llc_lookup_dgram - Finds dgram socket for the local sap/mac
	310	* @sap: SAP
	311	* @laddr: address of local LLC (MAC + SAP)
9b64e93e	312	* @net: netns to look up a socket in
1da177e4 LT	313	*
	314	* Search socket list of the SAP and finds connection using the local
	315	* mac, and local sap. Returns pointer for socket found, %NULL otherwise.
	316	*/
	317	static struct sock llc_lookup_dgram(struct llc_sap sap,
9b64e93e KI	318	const struct llc_addr *laddr,
9b64e93e KI	319	const struct net *net)
1da177e4 LT	320	{
1da177e4 LT	321	struct sock *rc;
b76f5a84	322	struct hlist_nulls_node *node;
52d58aef OP	323	int slot = llc_sk_laddr_hashfn(sap, laddr);
52d58aef OP	324	struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
b76f5a84 OP	325
	326	rcu_read_lock_bh();
	327	again:
52d58aef	328	sk_nulls_for_each_rcu(rc, node, laddr_hb) {
9b64e93e	329	if (llc_dgram_match(sap, laddr, rc, net)) {
5f0d5a3a	330	/* Extra checks required by SLAB_TYPESAFE_BY_RCU */
41c6d650	331	if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
b76f5a84 OP	332	goto again;
b76f5a84 OP	333	if (unlikely(llc_sk(rc)->sap != sap \|\|
9b64e93e	334	!llc_dgram_match(sap, laddr, rc, net))) {
b76f5a84 OP	335	sock_put(rc);
	336	continue;
	337	}
1da177e4 LT	338	goto found;
	339	}
	340	}
	341	rc = NULL;
52d58aef OP	342	/*
	343	* if the nulls value we got at the end of this lookup is
	344	* not the expected one, we must restart lookup.
	345	* We probably met an item that was moved to another chain.
	346	*/
	347	if (unlikely(get_nulls_value(node) != slot))
	348	goto again;
1da177e4	349	found:
b76f5a84	350	rcu_read_unlock_bh();
1da177e4 LT	351	return rc;
	352	}
	353
b76f5a84 OP	354	static inline bool llc_mcast_match(const struct llc_sap *sap,
	355	const struct llc_addr *laddr,
	356	const struct sk_buff *skb,
	357	const struct sock *sk)
	358	{
	359	struct llc_sock *llc = llc_sk(sk);
	360
	361	return sk->sk_type == SOCK_DGRAM &&
	362	llc->laddr.lsap == laddr->lsap &&
	363	llc->dev == skb->dev;
	364	}
	365
0f7b67dd OP	366	static void llc_do_mcast(struct llc_sap sap, struct sk_buff skb,
	367	struct sock **stack, int count)
	368	{
	369	struct sk_buff *skb1;
	370	int i;
	371
	372	for (i = 0; i < count; i++) {
	373	skb1 = skb_clone(skb, GFP_ATOMIC);
	374	if (!skb1) {
	375	sock_put(stack[i]);
	376	continue;
	377	}
	378
	379	llc_sap_rcv(sap, skb1, stack[i]);
	380	sock_put(stack[i]);
	381	}
	382	}
	383
bc0e6467 SH	384	/**
	385	* llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
	386	* @sap: SAP
	387	* @laddr: address of local LLC (MAC + SAP)
74c950c9	388	* @skb: PDU to deliver
bc0e6467 SH	389	*
	390	* Search socket list of the SAP and finds connections with same sap.
	391	* Deliver clone to each.
	392	*/
	393	static void llc_sap_mcast(struct llc_sap *sap,
	394	const struct llc_addr *laddr,
	395	struct sk_buff *skb)
	396	{
678f4bda SM	397	int i = 0;
	398	struct sock *sk;
	399	struct sock stack[256 / sizeof(struct sock )];
6d2e3ea2 OP	400	struct llc_sock *llc;
6d2e3ea2 OP	401	struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
bc0e6467	402
b76f5a84	403	spin_lock_bh(&sap->sk_lock);
b67bfe0d	404	hlist_for_each_entry(llc, dev_hb, dev_hash_node) {
6d2e3ea2 OP	405
6d2e3ea2 OP	406	sk = &llc->sk;
bc0e6467	407
b76f5a84	408	if (!llc_mcast_match(sap, laddr, skb, sk))
7ee66fcb SH	409	continue;
7ee66fcb SH	410
bc0e6467	411	sock_hold(sk);
678f4bda	412	if (i < ARRAY_SIZE(stack))
0f7b67dd OP	413	stack[i++] = sk;
	414	else {
	415	llc_do_mcast(sap, skb, stack, i);
	416	i = 0;
	417	}
bc0e6467	418	}
b76f5a84	419	spin_unlock_bh(&sap->sk_lock);
0f7b67dd OP	420
0f7b67dd OP	421	llc_do_mcast(sap, skb, stack, i);
bc0e6467 SH	422	}
	423
	424
1da177e4 LT	425	void llc_sap_handler(struct llc_sap sap, struct sk_buff skb)
	426	{
	427	struct llc_addr laddr;
1da177e4 LT	428
	429	llc_pdu_decode_da(skb, laddr.mac);
	430	llc_pdu_decode_dsap(skb, &laddr.lsap);
	431
951fd874	432	if (is_multicast_ether_addr(laddr.mac)) {
bc0e6467	433	llc_sap_mcast(sap, &laddr, skb);
1da177e4	434	kfree_skb(skb);
bc0e6467	435	} else {
9b64e93e	436	struct sock *sk = llc_lookup_dgram(sap, &laddr, dev_net(skb->dev));
bc0e6467	437	if (sk) {
3446b9d5	438	llc_sap_rcv(sap, skb, sk);
bc0e6467 SH	439	sock_put(sk);
	440	} else
	441	kfree_skb(skb);
	442	}
1da177e4	443	}