[mirror_ubuntu-bionic-kernel.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 <acme@conectiva.com.br>
 *
 * 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
 *	@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.
 */
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_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)
{
     struct llc_sock *llc = llc_sk(sk);

     return sk->sk_type == SOCK_DGRAM &&
	  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)
 *
 *	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_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))) {
				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 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 < 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 (is_multicast_ether_addr(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 <acme@conectiva.com.br>
	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
1d67e650	40	* @dev: network device this skb will be sent over
f83f1768 JP	41	* @type: pdu type to allocate
f83f1768 JP	42	* @data_size: data size to allocate
1da177e4 LT	43	*
	44	* Allocates an sk_buff for frame and initializes sk_buff fields.
	45	* Returns allocated skb or %NULL when out of memory.
	46	*/
f83f1768 JP	47	struct sk_buff llc_alloc_frame(struct sock sk, struct net_device *dev,
f83f1768 JP	48	u8 type, u32 data_size)
1da177e4	49	{
f83f1768 JP	50	int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
	51	struct sk_buff *skb;
	52
	53	hlen += llc_mac_header_len(dev->type);
	54	skb = alloc_skb(hlen + data_size, GFP_ATOMIC);
1da177e4 LT	55
1da177e4 LT	56	if (skb) {
0a1b0ad9	57	skb_reset_mac_header(skb);
f83f1768	58	skb_reserve(skb, hlen);
c1d2bbe1	59	skb_reset_network_header(skb);
badff6d0	60	skb_reset_transport_header(skb);
1da177e4	61	skb->protocol = htons(ETH_P_802_2);
1d67e650	62	skb->dev = dev;
d389424e ACM	63	if (sk != NULL)
d389424e ACM	64	skb_set_owner_w(skb, sk);
1da177e4 LT	65	}
	66	return skb;
	67	}
	68
3cdba604	69	void llc_save_primitive(struct sock sk, struct sk_buff skb, u8 prim)
1da177e4	70	{
8420e1b5	71	struct sockaddr_llc *addr;
1da177e4 LT	72
1da177e4 LT	73	/* save primitive for use by the user. */
8420e1b5	74	addr = llc_ui_skb_cb(skb);
30a584d9 SH	75
30a584d9 SH	76	memset(addr, 0, sizeof(*addr));
04e4223f	77	addr->sllc_family = sk->sk_family;
1da177e4 LT	78	addr->sllc_arphrd = skb->dev->type;
	79	addr->sllc_test = prim == LLC_TEST_PRIM;
	80	addr->sllc_xid = prim == LLC_XID_PRIM;
	81	addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
	82	llc_pdu_decode_sa(skb, addr->sllc_mac);
	83	llc_pdu_decode_ssap(skb, &addr->sllc_sap);
	84	}
	85
	86	/**
	87	* llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
	88	* @sap: pointer to SAP
	89	* @skb: received pdu
	90	*/
	91	void llc_sap_rtn_pdu(struct llc_sap sap, struct sk_buff skb)
	92	{
	93	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	94	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
	95
	96	switch (LLC_U_PDU_RSP(pdu)) {
	97	case LLC_1_PDU_CMD_TEST:
	98	ev->prim = LLC_TEST_PRIM; break;
	99	case LLC_1_PDU_CMD_XID:
	100	ev->prim = LLC_XID_PRIM; break;
	101	case LLC_1_PDU_CMD_UI:
	102	ev->prim = LLC_DATAUNIT_PRIM; break;
	103	}
	104	ev->ind_cfm_flag = LLC_IND;
	105	}
	106
	107	/**
	108	* llc_find_sap_trans - finds transition for event
	109	* @sap: pointer to SAP
	110	* @skb: happened event
	111	*
	112	* This function finds transition that matches with happened event.
	113	* Returns the pointer to found transition on success or %NULL for
	114	* failure.
	115	*/
	116	static struct llc_sap_state_trans llc_find_sap_trans(struct llc_sap sap,
3cdba604	117	struct sk_buff *skb)
1da177e4 LT	118	{
	119	int i = 0;
	120	struct llc_sap_state_trans *rc = NULL;
	121	struct llc_sap_state_trans **next_trans;
	122	struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
	123	/*
	124	* Search thru events for this state until list exhausted or until
	125	* its obvious the event is not valid for the current state
	126	*/
	127	for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
	128	if (!next_trans[i]->ev(sap, skb)) {
	129	rc = next_trans[i]; /* got event match; return it */
	130	break;
	131	}
	132	return rc;
	133	}
	134
	135	/**
	136	* llc_exec_sap_trans_actions - execute actions related to event
	137	* @sap: pointer to SAP
	138	* @trans: pointer to transition that it's actions must be performed
	139	* @skb: happened event.
	140	*
	141	* This function executes actions that is related to happened event.
	142	* Returns 0 for success and 1 for failure of at least one action.
	143	*/
	144	static int llc_exec_sap_trans_actions(struct llc_sap *sap,
	145	struct llc_sap_state_trans *trans,
	146	struct sk_buff *skb)
	147	{
	148	int rc = 0;
22bbf5f3	149	const llc_sap_action_t *next_action = trans->ev_actions;
1da177e4 LT	150
	151	for (; next_action && *next_action; next_action++)
	152	if ((*next_action)(sap, skb))
	153	rc = 1;
	154	return rc;
	155	}
	156
	157	/**
	158	* llc_sap_next_state - finds transition, execs actions & change SAP state
	159	* @sap: pointer to SAP
	160	* @skb: happened event
	161	*
	162	* This function finds transition that matches with happened event, then
	163	* executes related actions and finally changes state of SAP. It returns
	164	* 0 on success and 1 for failure.
	165	*/
	166	static int llc_sap_next_state(struct llc_sap sap, struct sk_buff skb)
	167	{
	168	int rc = 1;
	169	struct llc_sap_state_trans *trans;
	170
	171	if (sap->state > LLC_NR_SAP_STATES)
	172	goto out;
	173	trans = llc_find_sap_trans(sap, skb);
	174	if (!trans)
	175	goto out;
	176	/*
	177	* Got the state to which we next transition; perform the actions
	178	* associated with this transition before actually transitioning to the
	179	* next state
	180	*/
	181	rc = llc_exec_sap_trans_actions(sap, trans, skb);
	182	if (rc)
	183	goto out;
	184	/*
	185	* Transition SAP to next state if all actions execute successfully
	186	*/
	187	sap->state = trans->next_state;
	188	out:
	189	return rc;
	190	}
	191
	192	/**
	193	* llc_sap_state_process - sends event to SAP state machine
	194	* @sap: sap to use
	195	* @skb: pointer to occurred event
	196	*
	197	* After executing actions of the event, upper layer will be indicated
	198	* if needed(on receiving an UI frame). sk can be null for the
	199	* datalink_proto case.
	200	*/
	201	static void llc_sap_state_process(struct llc_sap sap, struct sk_buff skb)
	202	{
	203	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	204
	205	/*
	206	* We have to hold the skb, because llc_sap_next_state
	207	* will kfree it in the sending path and we need to
	208	* look at the skb->cb, where we encode llc_sap_state_ev.
	209	*/
	210	skb_get(skb);
	211	ev->ind_cfm_flag = 0;
	212	llc_sap_next_state(sap, skb);
	213	if (ev->ind_cfm_flag == LLC_IND) {
214	if (skb->sk->sk_state == TCP_LISTEN)
215	kfree_skb(skb);
216	else {
04e4223f	217	llc_save_primitive(skb->sk, skb, ev->prim);
1da177e4 LT	218
	219	/* queue skb to the user. */
	220	if (sock_queue_rcv_skb(skb->sk, skb))
	221	kfree_skb(skb);
	222	}
d57b1869	223	}
1da177e4 LT	224	kfree_skb(skb);
	225	}
	226
	227	/**
	228	* llc_build_and_send_test_pkt - TEST interface for upper layers.
	229	* @sap: sap to use
	230	* @skb: packet to send
	231	* @dmac: destination mac address
	232	* @dsap: destination sap
	233	*
	234	* This function is called when upper layer wants to send a TEST pdu.
	235	* Returns 0 for success, 1 otherwise.
	236	*/
d57b1869	237	void llc_build_and_send_test_pkt(struct llc_sap *sap,
1da177e4 LT	238	struct sk_buff skb, u8 dmac, u8 dsap)
	239	{
	240	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	241
	242	ev->saddr.lsap = sap->laddr.lsap;
	243	ev->daddr.lsap = dsap;
	244	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	245	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
d57b1869	246
1da177e4 LT	247	ev->type = LLC_SAP_EV_TYPE_PRIM;
	248	ev->prim = LLC_TEST_PRIM;
	249	ev->prim_type = LLC_PRIM_TYPE_REQ;
	250	llc_sap_state_process(sap, skb);
	251	}
	252
	253	/**
	254	* llc_build_and_send_xid_pkt - XID interface for upper layers
	255	* @sap: sap to use
	256	* @skb: packet to send
	257	* @dmac: destination mac address
	258	* @dsap: destination sap
	259	*
	260	* This function is called when upper layer wants to send a XID pdu.
	261	* Returns 0 for success, 1 otherwise.
	262	*/
	263	void llc_build_and_send_xid_pkt(struct llc_sap sap, struct sk_buff skb,
	264	u8 *dmac, u8 dsap)
	265	{
	266	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	267
	268	ev->saddr.lsap = sap->laddr.lsap;
	269	ev->daddr.lsap = dsap;
	270	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
	271	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
	272
	273	ev->type = LLC_SAP_EV_TYPE_PRIM;
	274	ev->prim = LLC_XID_PRIM;
	275	ev->prim_type = LLC_PRIM_TYPE_REQ;
	276	llc_sap_state_process(sap, skb);
	277	}
	278
	279	/**
	280	* llc_sap_rcv - sends received pdus to the sap state machine
	281	* @sap: current sap component structure.
	282	* @skb: received frame.
	283	*
	284	* Sends received pdus to the sap state machine.
	285	*/
3446b9d5 ACM	286	static void llc_sap_rcv(struct llc_sap sap, struct sk_buff skb,
3446b9d5 ACM	287	struct sock *sk)
1da177e4 LT	288	{
	289	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
	290
	291	ev->type = LLC_SAP_EV_TYPE_PDU;
	292	ev->reason = 0;
8b74d439 ED	293	skb_orphan(skb);
8b74d439 ED	294	sock_hold(sk);
3446b9d5	295	skb->sk = sk;
8b74d439	296	skb->destructor = sock_efree;
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 &&
951fd874	308	ether_addr_equal(llc->laddr.mac, laddr->mac);
b76f5a84 OP	309	}
b76f5a84 OP	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	323	struct hlist_nulls_node *node;
52d58aef OP	324	int slot = llc_sk_laddr_hashfn(sap, laddr);
52d58aef OP	325	struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
b76f5a84 OP	326
	327	rcu_read_lock_bh();
	328	again:
52d58aef	329	sk_nulls_for_each_rcu(rc, node, laddr_hb) {
b76f5a84	330	if (llc_dgram_match(sap, laddr, rc)) {
5f0d5a3a	331	/* Extra checks required by SLAB_TYPESAFE_BY_RCU */
41c6d650	332	if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
b76f5a84 OP	333	goto again;
	334	if (unlikely(llc_sk(rc)->sap != sap \|\|
	335	!llc_dgram_match(sap, laddr, rc))) {
	336	sock_put(rc);
	337	continue;
	338	}
1da177e4 LT	339	goto found;
	340	}
	341	}
	342	rc = NULL;
52d58aef OP	343	/*
	344	* if the nulls value we got at the end of this lookup is
	345	* not the expected one, we must restart lookup.
	346	* We probably met an item that was moved to another chain.
	347	*/
	348	if (unlikely(get_nulls_value(node) != slot))
	349	goto again;
1da177e4	350	found:
b76f5a84	351	rcu_read_unlock_bh();
1da177e4 LT	352	return rc;
	353	}
	354
b76f5a84 OP	355	static inline bool llc_mcast_match(const struct llc_sap *sap,
	356	const struct llc_addr *laddr,
	357	const struct sk_buff *skb,
	358	const struct sock *sk)
	359	{
	360	struct llc_sock *llc = llc_sk(sk);
	361
	362	return sk->sk_type == SOCK_DGRAM &&
	363	llc->laddr.lsap == laddr->lsap &&
	364	llc->dev == skb->dev;
	365	}
	366
0f7b67dd OP	367	static void llc_do_mcast(struct llc_sap sap, struct sk_buff skb,
	368	struct sock **stack, int count)
	369	{
	370	struct sk_buff *skb1;
	371	int i;
	372
	373	for (i = 0; i < count; i++) {
	374	skb1 = skb_clone(skb, GFP_ATOMIC);
	375	if (!skb1) {
	376	sock_put(stack[i]);
	377	continue;
	378	}
	379
	380	llc_sap_rcv(sap, skb1, stack[i]);
	381	sock_put(stack[i]);
	382	}
	383	}
	384
bc0e6467 SH	385	/**
	386	* llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
	387	* @sap: SAP
	388	* @laddr: address of local LLC (MAC + SAP)
	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	{
0f7b67dd OP	397	int i = 0, count = 256 / sizeof(struct sock *);
0f7b67dd OP	398	struct sock sk, stack[count];
6d2e3ea2 OP	399	struct llc_sock *llc;
6d2e3ea2 OP	400	struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
bc0e6467	401
b76f5a84	402	spin_lock_bh(&sap->sk_lock);
b67bfe0d	403	hlist_for_each_entry(llc, dev_hb, dev_hash_node) {
6d2e3ea2 OP	404
6d2e3ea2 OP	405	sk = &llc->sk;
bc0e6467	406
b76f5a84	407	if (!llc_mcast_match(sap, laddr, skb, sk))
7ee66fcb SH	408	continue;
7ee66fcb SH	409
bc0e6467	410	sock_hold(sk);
0f7b67dd OP	411	if (i < count)
	412	stack[i++] = sk;
	413	else {
	414	llc_do_mcast(sap, skb, stack, i);
	415	i = 0;
	416	}
bc0e6467	417	}
b76f5a84	418	spin_unlock_bh(&sap->sk_lock);
0f7b67dd OP	419
0f7b67dd OP	420	llc_do_mcast(sap, skb, stack, i);
bc0e6467 SH	421	}
	422
	423
1da177e4 LT	424	void llc_sap_handler(struct llc_sap sap, struct sk_buff skb)
	425	{
	426	struct llc_addr laddr;
1da177e4 LT	427
	428	llc_pdu_decode_da(skb, laddr.mac);
	429	llc_pdu_decode_dsap(skb, &laddr.lsap);
	430
951fd874	431	if (is_multicast_ether_addr(laddr.mac)) {
bc0e6467	432	llc_sap_mcast(sap, &laddr, skb);
1da177e4	433	kfree_skb(skb);
bc0e6467 SH	434	} else {
	435	struct sock *sk = llc_lookup_dgram(sap, &laddr);
	436	if (sk) {
3446b9d5	437	llc_sap_rcv(sap, skb, sk);
bc0e6467 SH	438	sock_put(sk);
	439	} else
	440	kfree_skb(skb);
	441	}
1da177e4	442	}