1 /* 2 * llc_station.c - station component of LLC 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/init.h> 15 #include <linux/module.h> 16 #include <linux/slab.h> 17 #include <net/llc.h> 18 #include <net/llc_sap.h> 19 #include <net/llc_conn.h> 20 #include <net/llc_c_ac.h> 21 #include <net/llc_s_ac.h> 22 #include <net/llc_c_ev.h> 23 #include <net/llc_c_st.h> 24 #include <net/llc_s_ev.h> 25 #include <net/llc_s_st.h> 26 #include <net/llc_pdu.h> 27 28 static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb) 29 { 30 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); 31 32 return LLC_PDU_IS_CMD(pdu) && /* command PDU */ 33 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */ 34 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID && 35 !pdu->dsap; /* NULL DSAP value */ 36 } 37 38 static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb) 39 { 40 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); 41 42 return LLC_PDU_IS_CMD(pdu) && /* command PDU */ 43 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */ 44 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST && 45 !pdu->dsap; /* NULL DSAP */ 46 } 47 48 static int llc_station_ac_send_xid_r(struct sk_buff *skb) 49 { 50 u8 mac_da[ETH_ALEN], dsap; 51 int rc = 1; 52 struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, 53 sizeof(struct llc_xid_info)); 54 55 if (!nskb) 56 goto out; 57 rc = 0; 58 llc_pdu_decode_sa(skb, mac_da); 59 llc_pdu_decode_ssap(skb, &dsap); 60 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP); 61 llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127); 62 rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da); 63 if (unlikely(rc)) 64 goto free; 65 dev_queue_xmit(nskb); 66 out: 67 return rc; 68 free: 69 kfree_skb(nskb); 70 goto out; 71 } 72 73 static int llc_station_ac_send_test_r(struct sk_buff *skb) 74 { 75 u8 mac_da[ETH_ALEN], dsap; 76 int rc = 1; 77 u32 data_size; 78 struct sk_buff *nskb; 79 80 /* The test request command is type U (llc_len = 3) */ 81 data_size = ntohs(eth_hdr(skb)->h_proto) - 3; 82 nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size); 83 84 if (!nskb) 85 goto out; 86 rc = 0; 87 llc_pdu_decode_sa(skb, mac_da); 88 llc_pdu_decode_ssap(skb, &dsap); 89 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP); 90 llc_pdu_init_as_test_rsp(nskb, skb); 91 rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da); 92 if (unlikely(rc)) 93 goto free; 94 dev_queue_xmit(nskb); 95 out: 96 return rc; 97 free: 98 kfree_skb(nskb); 99 goto out; 100 } 101 102 /** 103 * llc_station_rcv - send received pdu to the station state machine 104 * @skb: received frame. 105 * 106 * Sends data unit to station state machine. 107 */ 108 static void llc_station_rcv(struct sk_buff *skb) 109 { 110 if (llc_stat_ev_rx_null_dsap_xid_c(skb)) 111 llc_station_ac_send_xid_r(skb); 112 else if (llc_stat_ev_rx_null_dsap_test_c(skb)) 113 llc_station_ac_send_test_r(skb); 114 kfree_skb(skb); 115 } 116 117 void __init llc_station_init(void) 118 { 119 llc_set_station_handler(llc_station_rcv); 120 } 121 122 void llc_station_exit(void) 123 { 124 llc_set_station_handler(NULL); 125 } 126