154 lines
4.4 KiB
C
154 lines
4.4 KiB
C
/*
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* llc_if.c - Defines LLC interface to upper layer
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*
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* Copyright (c) 1997 by Procom Technology, Inc.
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* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program can be redistributed or modified under the terms of the
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* GNU General Public License as published by the Free Software Foundation.
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* This program is distributed without any warranty or implied warranty
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* of merchantability or fitness for a particular purpose.
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*
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* See the GNU General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <asm/errno.h>
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#include <net/llc_if.h>
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#include <net/llc_sap.h>
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#include <net/llc_s_ev.h>
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#include <net/llc_conn.h>
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#include <net/sock.h>
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#include <net/llc_c_ev.h>
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#include <net/llc_c_ac.h>
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#include <net/llc_c_st.h>
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#include <net/tcp_states.h>
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/**
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* llc_build_and_send_pkt - Connection data sending for upper layers.
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* @sk: connection
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* @skb: packet to send
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*
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* This function is called when upper layer wants to send data using
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* connection oriented communication mode. During sending data, connection
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* will be locked and received frames and expired timers will be queued.
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* Returns 0 for success, -ECONNABORTED when the connection already
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* closed and -EBUSY when sending data is not permitted in this state or
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* LLC has send an I pdu with p bit set to 1 and is waiting for it's
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* response.
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*/
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int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
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{
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struct llc_conn_state_ev *ev;
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int rc = -ECONNABORTED;
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struct llc_sock *llc = llc_sk(sk);
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if (unlikely(llc->state == LLC_CONN_STATE_ADM))
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goto out;
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rc = -EBUSY;
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if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
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llc->p_flag)) {
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llc->failed_data_req = 1;
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goto out;
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}
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ev = llc_conn_ev(skb);
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ev->type = LLC_CONN_EV_TYPE_PRIM;
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ev->prim = LLC_DATA_PRIM;
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ev->prim_type = LLC_PRIM_TYPE_REQ;
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skb->dev = llc->dev;
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rc = llc_conn_state_process(sk, skb);
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out:
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return rc;
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}
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/**
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* llc_establish_connection - Called by upper layer to establish a conn
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* @sk: connection
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* @lmac: local mac address
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* @dmac: destination mac address
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* @dsap: destination sap
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*
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* Upper layer calls this to establish an LLC connection with a remote
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* machine. This function packages a proper event and sends it connection
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* component state machine. Success or failure of connection
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* establishment will inform to upper layer via calling it's confirm
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* function and passing proper information.
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*/
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int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
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{
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int rc = -EISCONN;
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struct llc_addr laddr, daddr;
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struct sk_buff *skb;
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struct llc_sock *llc = llc_sk(sk);
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struct sock *existing;
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laddr.lsap = llc->sap->laddr.lsap;
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daddr.lsap = dsap;
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memcpy(daddr.mac, dmac, sizeof(daddr.mac));
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memcpy(laddr.mac, lmac, sizeof(laddr.mac));
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existing = llc_lookup_established(llc->sap, &daddr, &laddr);
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if (existing) {
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if (existing->sk_state == TCP_ESTABLISHED) {
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sk = existing;
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goto out_put;
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} else
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sock_put(existing);
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}
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sock_hold(sk);
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rc = -ENOMEM;
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skb = alloc_skb(0, GFP_ATOMIC);
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if (skb) {
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struct llc_conn_state_ev *ev = llc_conn_ev(skb);
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ev->type = LLC_CONN_EV_TYPE_PRIM;
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ev->prim = LLC_CONN_PRIM;
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ev->prim_type = LLC_PRIM_TYPE_REQ;
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skb_set_owner_w(skb, sk);
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rc = llc_conn_state_process(sk, skb);
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}
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out_put:
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sock_put(sk);
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return rc;
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}
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/**
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* llc_send_disc - Called by upper layer to close a connection
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* @sk: connection to be closed
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*
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* Upper layer calls this when it wants to close an established LLC
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* connection with a remote machine. This function packages a proper event
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* and sends it to connection component state machine. Returns 0 for
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* success, 1 otherwise.
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*/
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int llc_send_disc(struct sock *sk)
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{
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u16 rc = 1;
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struct llc_conn_state_ev *ev;
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struct sk_buff *skb;
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sock_hold(sk);
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if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
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llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
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llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
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goto out;
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/*
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* Postpone unassigning the connection from its SAP and returning the
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* connection until all ACTIONs have been completely executed
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*/
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skb = alloc_skb(0, GFP_ATOMIC);
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if (!skb)
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goto out;
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skb_set_owner_w(skb, sk);
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sk->sk_state = TCP_CLOSING;
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ev = llc_conn_ev(skb);
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ev->type = LLC_CONN_EV_TYPE_PRIM;
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ev->prim = LLC_DISC_PRIM;
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ev->prim_type = LLC_PRIM_TYPE_REQ;
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rc = llc_conn_state_process(sk, skb);
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out:
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sock_put(sk);
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return rc;
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}
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