xref: /openbmc/linux/net/llc/llc_if.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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/config.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 u8 llc_mac_null_var[IFHWADDRLEN];
30 
31 /**
32  *	llc_build_and_send_pkt - Connection data sending for upper layers.
33  *	@sk: connection
34  *	@skb: packet to send
35  *
36  *	This function is called when upper layer wants to send data using
37  *	connection oriented communication mode. During sending data, connection
38  *	will be locked and received frames and expired timers will be queued.
39  *	Returns 0 for success, -ECONNABORTED when the connection already
40  *	closed and -EBUSY when sending data is not permitted in this state or
41  *	LLC has send an I pdu with p bit set to 1 and is waiting for it's
42  *	response.
43  */
44 int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
45 {
46 	struct llc_conn_state_ev *ev;
47 	int rc = -ECONNABORTED;
48 	struct llc_sock *llc = llc_sk(sk);
49 
50 	if (unlikely(llc->state == LLC_CONN_STATE_ADM))
51 		goto out;
52 	rc = -EBUSY;
53 	if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
54 		     llc->p_flag)) {
55 		llc->failed_data_req = 1;
56 		goto out;
57 	}
58 	ev = llc_conn_ev(skb);
59 	ev->type      = LLC_CONN_EV_TYPE_PRIM;
60 	ev->prim      = LLC_DATA_PRIM;
61 	ev->prim_type = LLC_PRIM_TYPE_REQ;
62 	skb->dev      = llc->dev;
63 	rc = llc_conn_state_process(sk, skb);
64 out:
65 	return rc;
66 }
67 
68 /**
69  *	llc_establish_connection - Called by upper layer to establish a conn
70  *	@sk: connection
71  *	@lmac: local mac address
72  *	@dmac: destination mac address
73  *	@dsap: destination sap
74  *
75  *	Upper layer calls this to establish an LLC connection with a remote
76  *	machine. This function packages a proper event and sends it connection
77  *	component state machine. Success or failure of connection
78  *	establishment will inform to upper layer via calling it's confirm
79  *	function and passing proper information.
80  */
81 int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
82 {
83 	int rc = -EISCONN;
84 	struct llc_addr laddr, daddr;
85 	struct sk_buff *skb;
86 	struct llc_sock *llc = llc_sk(sk);
87 	struct sock *existing;
88 
89 	laddr.lsap = llc->sap->laddr.lsap;
90 	daddr.lsap = dsap;
91 	memcpy(daddr.mac, dmac, sizeof(daddr.mac));
92 	memcpy(laddr.mac, lmac, sizeof(laddr.mac));
93 	existing = llc_lookup_established(llc->sap, &daddr, &laddr);
94 	if (existing) {
95 		if (existing->sk_state == TCP_ESTABLISHED) {
96 			sk = existing;
97 			goto out_put;
98 		} else
99 			sock_put(existing);
100 	}
101 	sock_hold(sk);
102 	rc = -ENOMEM;
103 	skb = alloc_skb(0, GFP_ATOMIC);
104 	if (skb) {
105 		struct llc_conn_state_ev *ev = llc_conn_ev(skb);
106 
107 		ev->type      = LLC_CONN_EV_TYPE_PRIM;
108 		ev->prim      = LLC_CONN_PRIM;
109 		ev->prim_type = LLC_PRIM_TYPE_REQ;
110 		skb_set_owner_w(skb, sk);
111 		rc = llc_conn_state_process(sk, skb);
112 	}
113 out_put:
114 	sock_put(sk);
115 	return rc;
116 }
117 
118 /**
119  *	llc_send_disc - Called by upper layer to close a connection
120  *	@sk: connection to be closed
121  *
122  *	Upper layer calls this when it wants to close an established LLC
123  *	connection with a remote machine. This function packages a proper event
124  *	and sends it to connection component state machine. Returns 0 for
125  *	success, 1 otherwise.
126  */
127 int llc_send_disc(struct sock *sk)
128 {
129 	u16 rc = 1;
130 	struct llc_conn_state_ev *ev;
131 	struct sk_buff *skb;
132 
133 	sock_hold(sk);
134 	if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
135 	    llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
136 	    llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
137 		goto out;
138 	/*
139 	 * Postpone unassigning the connection from its SAP and returning the
140 	 * connection until all ACTIONs have been completely executed
141 	 */
142 	skb = alloc_skb(0, GFP_ATOMIC);
143 	if (!skb)
144 		goto out;
145 	skb_set_owner_w(skb, sk);
146 	sk->sk_state  = TCP_CLOSING;
147 	ev	      = llc_conn_ev(skb);
148 	ev->type      = LLC_CONN_EV_TYPE_PRIM;
149 	ev->prim      = LLC_DISC_PRIM;
150 	ev->prim_type = LLC_PRIM_TYPE_REQ;
151 	rc = llc_conn_state_process(sk, skb);
152 out:
153 	sock_put(sk);
154 	return rc;
155 }
156 
157