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 | * |
42 | * This function always consumes a reference to the skb. |
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_free; |
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_free; |
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 | return llc_conn_state_process(sk, skb); |
64 | |
65 | out_free: |
66 | kfree_skb(skb); |
67 | return rc; |
68 | } |
69 | |
70 | /** |
71 | * llc_establish_connection - Called by upper layer to establish a conn |
72 | * @sk: connection |
73 | * @lmac: local mac address |
74 | * @dmac: destination mac address |
75 | * @dsap: destination sap |
76 | * |
77 | * Upper layer calls this to establish an LLC connection with a remote |
78 | * machine. This function packages a proper event and sends it connection |
79 | * component state machine. Success or failure of connection |
80 | * establishment will inform to upper layer via calling it's confirm |
81 | * function and passing proper information. |
82 | */ |
83 | int llc_establish_connection(struct sock *sk, const u8 *lmac, u8 *dmac, u8 dsap) |
84 | { |
85 | int rc = -EISCONN; |
86 | struct llc_addr laddr, daddr; |
87 | struct sk_buff *skb; |
88 | struct llc_sock *llc = llc_sk(sk); |
89 | struct sock *existing; |
90 | |
91 | laddr.lsap = llc->sap->laddr.lsap; |
92 | daddr.lsap = dsap; |
93 | memcpy(daddr.mac, dmac, sizeof(daddr.mac)); |
94 | memcpy(laddr.mac, lmac, sizeof(laddr.mac)); |
95 | existing = llc_lookup_established(sap: llc->sap, daddr: &daddr, laddr: &laddr, net: sock_net(sk)); |
96 | if (existing) { |
97 | if (existing->sk_state == TCP_ESTABLISHED) { |
98 | sk = existing; |
99 | goto out_put; |
100 | } else |
101 | sock_put(sk: existing); |
102 | } |
103 | sock_hold(sk); |
104 | rc = -ENOMEM; |
105 | skb = alloc_skb(size: 0, GFP_ATOMIC); |
106 | if (skb) { |
107 | struct llc_conn_state_ev *ev = llc_conn_ev(skb); |
108 | |
109 | ev->type = LLC_CONN_EV_TYPE_PRIM; |
110 | ev->prim = LLC_CONN_PRIM; |
111 | ev->prim_type = LLC_PRIM_TYPE_REQ; |
112 | skb_set_owner_w(skb, sk); |
113 | rc = llc_conn_state_process(sk, skb); |
114 | } |
115 | out_put: |
116 | sock_put(sk); |
117 | return rc; |
118 | } |
119 | |
120 | /** |
121 | * llc_send_disc - Called by upper layer to close a connection |
122 | * @sk: connection to be closed |
123 | * |
124 | * Upper layer calls this when it wants to close an established LLC |
125 | * connection with a remote machine. This function packages a proper event |
126 | * and sends it to connection component state machine. Returns 0 for |
127 | * success, 1 otherwise. |
128 | */ |
129 | int llc_send_disc(struct sock *sk) |
130 | { |
131 | u16 rc = 1; |
132 | struct llc_conn_state_ev *ev; |
133 | struct sk_buff *skb; |
134 | |
135 | sock_hold(sk); |
136 | if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED || |
137 | llc_sk(sk)->state == LLC_CONN_STATE_ADM || |
138 | llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC) |
139 | goto out; |
140 | /* |
141 | * Postpone unassigning the connection from its SAP and returning the |
142 | * connection until all ACTIONs have been completely executed |
143 | */ |
144 | skb = alloc_skb(size: 0, GFP_ATOMIC); |
145 | if (!skb) |
146 | goto out; |
147 | skb_set_owner_w(skb, sk); |
148 | sk->sk_state = TCP_CLOSING; |
149 | ev = llc_conn_ev(skb); |
150 | ev->type = LLC_CONN_EV_TYPE_PRIM; |
151 | ev->prim = LLC_DISC_PRIM; |
152 | ev->prim_type = LLC_PRIM_TYPE_REQ; |
153 | rc = llc_conn_state_process(sk, skb); |
154 | out: |
155 | sock_put(sk); |
156 | return rc; |
157 | } |
158 | |