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 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 */ 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 */ 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