1/*
2 * llc_if.c - Defines LLC interface to upper layer
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#include <linux/gfp.h>
15#include <linux/module.h>
16#include <linux/kernel.h>
17#include <linux/netdevice.h>
18#include <asm/errno.h>
19#include <net/llc_if.h>
20#include <net/llc_sap.h>
21#include <net/llc_s_ev.h>
22#include <net/llc_conn.h>
23#include <net/sock.h>
24#include <net/llc_c_ev.h>
25#include <net/llc_c_ac.h>
26#include <net/llc_c_st.h>
27#include <net/tcp_states.h>
28
29/**
30 *	llc_build_and_send_pkt - Connection data sending for upper layers.
31 *	@sk: connection
32 *	@skb: packet to send
33 *
34 *	This function is called when upper layer wants to send data using
35 *	connection oriented communication mode. During sending data, connection
36 *	will be locked and received frames and expired timers will be queued.
37 *	Returns 0 for success, -ECONNABORTED when the connection already
38 *	closed and -EBUSY when sending data is not permitted in this state or
39 *	LLC has send an I pdu with p bit set to 1 and is waiting for it's
40 *	response.
41 */
42int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
43{
44	struct llc_conn_state_ev *ev;
45	int rc = -ECONNABORTED;
46	struct llc_sock *llc = llc_sk(sk);
47
48	if (unlikely(llc->state == LLC_CONN_STATE_ADM))
49		goto out;
50	rc = -EBUSY;
51	if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
52		     llc->p_flag)) {
53		llc->failed_data_req = 1;
54		goto out;
55	}
56	ev = llc_conn_ev(skb);
57	ev->type      = LLC_CONN_EV_TYPE_PRIM;
58	ev->prim      = LLC_DATA_PRIM;
59	ev->prim_type = LLC_PRIM_TYPE_REQ;
60	skb->dev      = llc->dev;
61	rc = llc_conn_state_process(sk, skb);
62out:
63	return rc;
64}
65
66/**
67 *	llc_establish_connection - Called by upper layer to establish a conn
68 *	@sk: connection
69 *	@lmac: local mac address
70 *	@dmac: destination mac address
71 *	@dsap: destination sap
72 *
73 *	Upper layer calls this to establish an LLC connection with a remote
74 *	machine. This function packages a proper event and sends it connection
75 *	component state machine. Success or failure of connection
76 *	establishment will inform to upper layer via calling it's confirm
77 *	function and passing proper information.
78 */
79int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
80{
81	int rc = -EISCONN;
82	struct llc_addr laddr, daddr;
83	struct sk_buff *skb;
84	struct llc_sock *llc = llc_sk(sk);
85	struct sock *existing;
86
87	laddr.lsap = llc->sap->laddr.lsap;
88	daddr.lsap = dsap;
89	memcpy(daddr.mac, dmac, sizeof(daddr.mac));
90	memcpy(laddr.mac, lmac, sizeof(laddr.mac));
91	existing = llc_lookup_established(llc->sap, &daddr, &laddr);
92	if (existing) {
93		if (existing->sk_state == TCP_ESTABLISHED) {
94			sk = existing;
95			goto out_put;
96		} else
97			sock_put(existing);
98	}
99	sock_hold(sk);
100	rc = -ENOMEM;
101	skb = alloc_skb(0, GFP_ATOMIC);
102	if (skb) {
103		struct llc_conn_state_ev *ev = llc_conn_ev(skb);
104
105		ev->type      = LLC_CONN_EV_TYPE_PRIM;
106		ev->prim      = LLC_CONN_PRIM;
107		ev->prim_type = LLC_PRIM_TYPE_REQ;
108		skb_set_owner_w(skb, sk);
109		rc = llc_conn_state_process(sk, skb);
110	}
111out_put:
112	sock_put(sk);
113	return rc;
114}
115
116/**
117 *	llc_send_disc - Called by upper layer to close a connection
118 *	@sk: connection to be closed
119 *
120 *	Upper layer calls this when it wants to close an established LLC
121 *	connection with a remote machine. This function packages a proper event
122 *	and sends it to connection component state machine. Returns 0 for
123 *	success, 1 otherwise.
124 */
125int llc_send_disc(struct sock *sk)
126{
127	u16 rc = 1;
128	struct llc_conn_state_ev *ev;
129	struct sk_buff *skb;
130
131	sock_hold(sk);
132	if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
133	    llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
134	    llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
135		goto out;
136	/*
137	 * Postpone unassigning the connection from its SAP and returning the
138	 * connection until all ACTIONs have been completely executed
139	 */
140	skb = alloc_skb(0, GFP_ATOMIC);
141	if (!skb)
142		goto out;
143	skb_set_owner_w(skb, sk);
144	sk->sk_state  = TCP_CLOSING;
145	ev	      = llc_conn_ev(skb);
146	ev->type      = LLC_CONN_EV_TYPE_PRIM;
147	ev->prim      = LLC_DISC_PRIM;
148	ev->prim_type = LLC_PRIM_TYPE_REQ;
149	rc = llc_conn_state_process(sk, skb);
150out:
151	sock_put(sk);
152	return rc;
153}
154