1 files changed, 439 insertions, 0 deletions

diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
new file mode 100644
index 000000000..d0e1e804e
--- /dev/null
+++ b/net/llc/llc_sap.c
@@ -0,0 +1,439 @@
+/*
+ * 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->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 &&
+	  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_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 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);
+	}
+}