path: root/net/llc/llc_conn.c

/*
 * llc_conn.c - Driver routines for connection 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 <linux/init.h>
#include <net/llc_sap.h>
#include <net/llc_conn.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_st.h>
#include <net/llc_pdu.h>

#if 0
#define dprintk(args...) printk(KERN_DEBUG args)
#else
#define dprintk(args...)
#endif

static int llc_find_offset(int state, int ev_type);
static void llc_conn_send_pdus(struct sock *sk);
static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
static int llc_exec_conn_trans_actions(struct sock *sk,
				       struct llc_conn_state_trans *trans,
				       struct sk_buff *ev);
static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
							struct sk_buff *skb);

/* Offset table on connection states transition diagram */
static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];

int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;

/**
 *	llc_conn_state_process - sends event to connection state machine
 *	@sk: connection
 *	@skb: occurred event
 *
 *	Sends an event to connection state machine. After processing event
 *	(executing it's actions and changing state), upper layer will be
 *	indicated or confirmed, if needed. Returns 0 for success, 1 for
 *	failure. The socket lock has to be held before calling this function.
 */
int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
{
	int rc;
	struct llc_sock *llc = llc_sk(skb->sk);
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	/*
	 * We have to hold the skb, because llc_conn_service will kfree it in
	 * the sending path and we need to look at the skb->cb, where we encode
	 * llc_conn_state_ev.
	 */
	skb_get(skb);
	ev->ind_prim = ev->cfm_prim = 0;
	/*
	 * Send event to state machine
	 */
	rc = llc_conn_service(skb->sk, skb);
	if (unlikely(rc != 0)) {
		printk(KERN_ERR "%s: llc_conn_service failed\n", __FUNCTION__);
		goto out_kfree_skb;
	}

	if (unlikely(!ev->ind_prim && !ev->cfm_prim)) {
		/* indicate or confirm not required */
		/* XXX this is not very pretty, perhaps we should store
		 * XXX indicate/confirm-needed state in the llc_conn_state_ev
		 * XXX control block of the SKB instead? -DaveM
		 */
		if (!skb->next)
			goto out_kfree_skb;
		goto out_skb_put;
	}

	if (unlikely(ev->ind_prim && ev->cfm_prim)) /* Paranoia */
		skb_get(skb);

	switch (ev->ind_prim) {
	case LLC_DATA_PRIM:
		llc_save_primitive(sk, skb, LLC_DATA_PRIM);
		if (unlikely(sock_queue_rcv_skb(sk, skb))) {
			/*
			 * shouldn't happen
			 */
			printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
			       __FUNCTION__);
			kfree_skb(skb);
		}
		break;
	case LLC_CONN_PRIM:
		/*
		 * Can't be sock_queue_rcv_skb, because we have to leave the
		 * skb->sk pointing to the newly created struct sock in
		 * llc_conn_handler. -acme
		 */
		skb_queue_tail(&sk->sk_receive_queue, skb);
		sk->sk_state_change(sk);
		break;
	case LLC_DISC_PRIM:
		sock_hold(sk);
		if (sk->sk_type == SOCK_STREAM &&
		    sk->sk_state == TCP_ESTABLISHED) {
			sk->sk_shutdown       = SHUTDOWN_MASK;
			sk->sk_socket->state  = SS_UNCONNECTED;
			sk->sk_state          = TCP_CLOSE;
			if (!sock_flag(sk, SOCK_DEAD)) {
				sock_set_flag(sk, SOCK_DEAD);
				sk->sk_state_change(sk);
			}
		}
		kfree_skb(skb);
		sock_put(sk);
		break;
	case LLC_RESET_PRIM:
		/*
		 * FIXME:
		 * RESET is not being notified to upper layers for now
		 */
		printk(KERN_INFO "%s: received a reset ind!\n", __FUNCTION__);
		kfree_skb(skb);
		break;
	default:
		if (ev->ind_prim) {
			printk(KERN_INFO "%s: received unknown %d prim!\n",
				__FUNCTION__, ev->ind_prim);
			kfree_skb(skb);
		}
		/* No indication */
		break;
	}

	switch (ev->cfm_prim) {
	case LLC_DATA_PRIM:
		if (!llc_data_accept_state(llc->state))
			sk->sk_write_space(sk);
		else
			rc = llc->failed_data_req = 1;
		break;
	case LLC_CONN_PRIM:
		if (sk->sk_type == SOCK_STREAM &&
		    sk->sk_state == TCP_SYN_SENT) {
			if (ev->status) {
				sk->sk_socket->state = SS_UNCONNECTED;
				sk->sk_state         = TCP_CLOSE;
			} else {
				sk->sk_socket->state = SS_CONNECTED;
				sk->sk_state         = TCP_ESTABLISHED;
			}
			sk->sk_state_change(sk);
		}
		break;
	case LLC_DISC_PRIM:
		sock_hold