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