llc_if.c
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/*
* llc_if.c - Defines LLC interface to upper layer
*
* 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/gfp.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <asm/errno.h>
#include <net/llc_if.h>
#include <net/llc_sap.h>
#include <net/llc_s_ev.h>
#include <net/llc_conn.h>
#include <net/sock.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_st.h>
#include <net/tcp_states.h>
/**
* llc_build_and_send_pkt - Connection data sending for upper layers.
* @sk: connection
* @skb: packet to send
*
* This function is called when upper layer wants to send data using
* connection oriented communication mode. During sending data, connection
* will be locked and received frames and expired timers will be queued.
* Returns 0 for success, -ECONNABORTED when the connection already
* closed and -EBUSY when sending data is not permitted in this state or
* LLC has send an I pdu with p bit set to 1 and is waiting for it's
* response.
*/
int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
{
struct llc_conn_state_ev *ev;
int rc = -ECONNABORTED;
struct llc_sock *llc = llc_sk(sk);
if (unlikely(llc->state == LLC_CONN_STATE_ADM))
goto out;
rc = -EBUSY;
if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
llc->p_flag)) {
llc->failed_data_req = 1;
goto out;
}
ev = llc_conn_ev(skb);
ev->type = LLC_CONN_EV_TYPE_PRIM;
ev->prim = LLC_DATA_PRIM;
ev->prim_type = LLC_PRIM_TYPE_REQ;
skb->dev = llc->dev;
rc = llc_conn_state_process(sk, skb);
out:
return rc;
}
/**
* llc_establish_connection - Called by upper layer to establish a conn
* @sk: connection
* @lmac: local mac address
* @dmac: destination mac address
* @dsap: destination sap
*
* Upper layer calls this to establish an LLC connection with a remote
* machine. This function packages a proper event and sends it connection
* component state machine. Success or failure of connection
* establishment will inform to upper layer via calling it's confirm
* function and passing proper information.
*/
int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
{
int rc = -EISCONN;
struct llc_addr laddr, daddr;
struct sk_buff *skb;
struct llc_sock *llc = llc_sk(sk);
struct sock *existing;
laddr.lsap = llc->sap->laddr.lsap;
daddr.lsap = dsap;
memcpy(daddr.mac, dmac, sizeof(daddr.mac));
memcpy(laddr.mac, lmac, sizeof(laddr.mac));
existing = llc_lookup_established(llc->sap, &daddr, &laddr);
if (existing) {
if (existing->sk_state == TCP_ESTABLISHED) {
sk = existing;
goto out_put;
} else
sock_put(existing);
}
sock_hold(sk);
rc = -ENOMEM;
skb = alloc_skb(0, GFP_ATOMIC);
if (skb) {
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
ev->type = LLC_CONN_EV_TYPE_PRIM;
ev->prim = LLC_CONN_PRIM;
ev->prim_type = LLC_PRIM_TYPE_REQ;
skb_set_owner_w(skb, sk);
rc = llc_conn_state_process(sk, skb);
}
out_put:
sock_put(sk);
return rc;
}
/**
* llc_send_disc - Called by upper layer to close a connection
* @sk: connection to be closed
*
* Upper layer calls this when it wants to close an established LLC
* connection with a remote machine. This function packages a proper event
* and sends it to connection component state machine. Returns 0 for
* success, 1 otherwise.
*/
int llc_send_disc(struct sock *sk)
{
u16 rc = 1;
struct llc_conn_state_ev *ev;
struct sk_buff *skb;
sock_hold(sk);
if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
goto out;
/*
* Postpone unassigning the connection from its SAP and returning the
* connection until all ACTIONs have been completely executed
*/
skb = alloc_skb(0, GFP_ATOMIC);
if (!skb)
goto out;
skb_set_owner_w(skb, sk);
sk->sk_state = TCP_CLOSING;
ev = llc_conn_ev(skb);
ev->type = LLC_CONN_EV_TYPE_PRIM;
ev->prim = LLC_DISC_PRIM;
ev->prim_type = LLC_PRIM_TYPE_REQ;
rc = llc_conn_state_process(sk, skb);
out:
sock_put(sk);
return rc;
}