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 <linux/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 */
llc_build_and_send_pkt(struct sock * sk,struct sk_buff * skb)42 int 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);
62 out:
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 */
llc_establish_connection(struct sock * sk,u8 * lmac,u8 * dmac,u8 dsap)79 int 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 }
111 out_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 */
llc_send_disc(struct sock * sk)125 int 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);
150 out:
151 sock_put(sk);
152 return rc;
153 }
154
