summaryrefslogtreecommitdiffstats
path: root/net/llc/llc_if.c
blob: 8db03c2d5440b12536b3b7016bc5c01b56666d8a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/*
 * 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 <linux/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;
}
OpenPOWER on IntegriCloud