1 /* 2 * llc_sap.c - driver routines for SAP component. 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 15 #include <net/llc.h> 16 #include <net/llc_if.h> 17 #include <net/llc_conn.h> 18 #include <net/llc_pdu.h> 19 #include <net/llc_sap.h> 20 #include <net/llc_s_ac.h> 21 #include <net/llc_s_ev.h> 22 #include <net/llc_s_st.h> 23 #include <net/sock.h> 24 #include <net/tcp_states.h> 25 #include <linux/llc.h> 26 27 static int llc_mac_header_len(unsigned short devtype) 28 { 29 switch (devtype) { 30 case ARPHRD_ETHER: 31 case ARPHRD_LOOPBACK: 32 return sizeof(struct ethhdr); 33 #ifdef CONFIG_TR 34 case ARPHRD_IEEE802_TR: 35 return sizeof(struct trh_hdr); 36 #endif 37 } 38 return 0; 39 } 40 41 /** 42 * llc_alloc_frame - allocates sk_buff for frame 43 * @dev: network device this skb will be sent over 44 * @type: pdu type to allocate 45 * @data_size: data size to allocate 46 * 47 * Allocates an sk_buff for frame and initializes sk_buff fields. 48 * Returns allocated skb or %NULL when out of memory. 49 */ 50 struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev, 51 u8 type, u32 data_size) 52 { 53 int hlen = type == LLC_PDU_TYPE_U ? 3 : 4; 54 struct sk_buff *skb; 55 56 hlen += llc_mac_header_len(dev->type); 57 skb = alloc_skb(hlen + data_size, GFP_ATOMIC); 58 59 if (skb) { 60 skb_reset_mac_header(skb); 61 skb_reserve(skb, hlen); 62 skb_reset_network_header(skb); 63 skb_reset_transport_header(skb); 64 skb->protocol = htons(ETH_P_802_2); 65 skb->dev = dev; 66 if (sk != NULL) 67 skb_set_owner_w(skb, sk); 68 } 69 return skb; 70 } 71 72 void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim) 73 { 74 struct sockaddr_llc *addr; 75 76 /* save primitive for use by the user. */ 77 addr = llc_ui_skb_cb(skb); 78 79 memset(addr, 0, sizeof(*addr)); 80 addr->sllc_family = sk->sk_family; 81 addr->sllc_arphrd = skb->dev->type; 82 addr->sllc_test = prim == LLC_TEST_PRIM; 83 addr->sllc_xid = prim == LLC_XID_PRIM; 84 addr->sllc_ua = prim == LLC_DATAUNIT_PRIM; 85 llc_pdu_decode_sa(skb, addr->sllc_mac); 86 llc_pdu_decode_ssap(skb, &addr->sllc_sap); 87 } 88 89 /** 90 * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu. 91 * @sap: pointer to SAP 92 * @skb: received pdu 93 */ 94 void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb) 95 { 96 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 97 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); 98 99 switch (LLC_U_PDU_RSP(pdu)) { 100 case LLC_1_PDU_CMD_TEST: 101 ev->prim = LLC_TEST_PRIM; break; 102 case LLC_1_PDU_CMD_XID: 103 ev->prim = LLC_XID_PRIM; break; 104 case LLC_1_PDU_CMD_UI: 105 ev->prim = LLC_DATAUNIT_PRIM; break; 106 } 107 ev->ind_cfm_flag = LLC_IND; 108 } 109 110 /** 111 * llc_find_sap_trans - finds transition for event 112 * @sap: pointer to SAP 113 * @skb: happened event 114 * 115 * This function finds transition that matches with happened event. 116 * Returns the pointer to found transition on success or %NULL for 117 * failure. 118 */ 119 static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap, 120 struct sk_buff* skb) 121 { 122 int i = 0; 123 struct llc_sap_state_trans *rc = NULL; 124 struct llc_sap_state_trans **next_trans; 125 struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1]; 126 /* 127 * Search thru events for this state until list exhausted or until 128 * its obvious the event is not valid for the current state 129 */ 130 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++) 131 if (!next_trans[i]->ev(sap, skb)) { 132 rc = next_trans[i]; /* got event match; return it */ 133 break; 134 } 135 return rc; 136 } 137 138 /** 139 * llc_exec_sap_trans_actions - execute actions related to event 140 * @sap: pointer to SAP 141 * @trans: pointer to transition that it's actions must be performed 142 * @skb: happened event. 143 * 144 * This function executes actions that is related to happened event. 145 * Returns 0 for success and 1 for failure of at least one action. 146 */ 147 static int llc_exec_sap_trans_actions(struct llc_sap *sap, 148 struct llc_sap_state_trans *trans, 149 struct sk_buff *skb) 150 { 151 int rc = 0; 152 llc_sap_action_t *next_action = trans->ev_actions; 153 154 for (; next_action && *next_action; next_action++) 155 if ((*next_action)(sap, skb)) 156 rc = 1; 157 return rc; 158 } 159 160 /** 161 * llc_sap_next_state - finds transition, execs actions & change SAP state 162 * @sap: pointer to SAP 163 * @skb: happened event 164 * 165 * This function finds transition that matches with happened event, then 166 * executes related actions and finally changes state of SAP. It returns 167 * 0 on success and 1 for failure. 168 */ 169 static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb) 170 { 171 int rc = 1; 172 struct llc_sap_state_trans *trans; 173 174 if (sap->state > LLC_NR_SAP_STATES) 175 goto out; 176 trans = llc_find_sap_trans(sap, skb); 177 if (!trans) 178 goto out; 179 /* 180 * Got the state to which we next transition; perform the actions 181 * associated with this transition before actually transitioning to the 182 * next state 183 */ 184 rc = llc_exec_sap_trans_actions(sap, trans, skb); 185 if (rc) 186 goto out; 187 /* 188 * Transition SAP to next state if all actions execute successfully 189 */ 190 sap->state = trans->next_state; 191 out: 192 return rc; 193 } 194 195 /** 196 * llc_sap_state_process - sends event to SAP state machine 197 * @sap: sap to use 198 * @skb: pointer to occurred event 199 * 200 * After executing actions of the event, upper layer will be indicated 201 * if needed(on receiving an UI frame). sk can be null for the 202 * datalink_proto case. 203 */ 204 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb) 205 { 206 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 207 208 /* 209 * We have to hold the skb, because llc_sap_next_state 210 * will kfree it in the sending path and we need to 211 * look at the skb->cb, where we encode llc_sap_state_ev. 212 */ 213 skb_get(skb); 214 ev->ind_cfm_flag = 0; 215 llc_sap_next_state(sap, skb); 216 if (ev->ind_cfm_flag == LLC_IND) { 217 if (skb->sk->sk_state == TCP_LISTEN) 218 kfree_skb(skb); 219 else { 220 llc_save_primitive(skb->sk, skb, ev->prim); 221 222 /* queue skb to the user. */ 223 if (sock_queue_rcv_skb(skb->sk, skb)) 224 kfree_skb(skb); 225 } 226 } 227 kfree_skb(skb); 228 } 229 230 /** 231 * llc_build_and_send_test_pkt - TEST interface for upper layers. 232 * @sap: sap to use 233 * @skb: packet to send 234 * @dmac: destination mac address 235 * @dsap: destination sap 236 * 237 * This function is called when upper layer wants to send a TEST pdu. 238 * Returns 0 for success, 1 otherwise. 239 */ 240 void llc_build_and_send_test_pkt(struct llc_sap *sap, 241 struct sk_buff *skb, u8 *dmac, u8 dsap) 242 { 243 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 244 245 ev->saddr.lsap = sap->laddr.lsap; 246 ev->daddr.lsap = dsap; 247 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); 248 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); 249 250 ev->type = LLC_SAP_EV_TYPE_PRIM; 251 ev->prim = LLC_TEST_PRIM; 252 ev->prim_type = LLC_PRIM_TYPE_REQ; 253 llc_sap_state_process(sap, skb); 254 } 255 256 /** 257 * llc_build_and_send_xid_pkt - XID interface for upper layers 258 * @sap: sap to use 259 * @skb: packet to send 260 * @dmac: destination mac address 261 * @dsap: destination sap 262 * 263 * This function is called when upper layer wants to send a XID pdu. 264 * Returns 0 for success, 1 otherwise. 265 */ 266 void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb, 267 u8 *dmac, u8 dsap) 268 { 269 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 270 271 ev->saddr.lsap = sap->laddr.lsap; 272 ev->daddr.lsap = dsap; 273 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); 274 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); 275 276 ev->type = LLC_SAP_EV_TYPE_PRIM; 277 ev->prim = LLC_XID_PRIM; 278 ev->prim_type = LLC_PRIM_TYPE_REQ; 279 llc_sap_state_process(sap, skb); 280 } 281 282 /** 283 * llc_sap_rcv - sends received pdus to the sap state machine 284 * @sap: current sap component structure. 285 * @skb: received frame. 286 * 287 * Sends received pdus to the sap state machine. 288 */ 289 static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb) 290 { 291 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 292 293 ev->type = LLC_SAP_EV_TYPE_PDU; 294 ev->reason = 0; 295 llc_sap_state_process(sap, skb); 296 } 297 298 /** 299 * llc_lookup_dgram - Finds dgram socket for the local sap/mac 300 * @sap: SAP 301 * @laddr: address of local LLC (MAC + SAP) 302 * 303 * Search socket list of the SAP and finds connection using the local 304 * mac, and local sap. Returns pointer for socket found, %NULL otherwise. 305 */ 306 static struct sock *llc_lookup_dgram(struct llc_sap *sap, 307 const struct llc_addr *laddr) 308 { 309 struct sock *rc; 310 struct hlist_node *node; 311 312 read_lock_bh(&sap->sk_list.lock); 313 sk_for_each(rc, node, &sap->sk_list.list) { 314 struct llc_sock *llc = llc_sk(rc); 315 316 if (rc->sk_type == SOCK_DGRAM && 317 llc->laddr.lsap == laddr->lsap && 318 llc_mac_match(llc->laddr.mac, laddr->mac)) { 319 sock_hold(rc); 320 goto found; 321 } 322 } 323 rc = NULL; 324 found: 325 read_unlock_bh(&sap->sk_list.lock); 326 return rc; 327 } 328 329 /** 330 * llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets. 331 * @sap: SAP 332 * @laddr: address of local LLC (MAC + SAP) 333 * 334 * Search socket list of the SAP and finds connections with same sap. 335 * Deliver clone to each. 336 */ 337 static void llc_sap_mcast(struct llc_sap *sap, 338 const struct llc_addr *laddr, 339 struct sk_buff *skb) 340 { 341 struct sock *sk; 342 struct hlist_node *node; 343 344 read_lock_bh(&sap->sk_list.lock); 345 sk_for_each(sk, node, &sap->sk_list.list) { 346 struct llc_sock *llc = llc_sk(sk); 347 struct sk_buff *skb1; 348 349 if (sk->sk_type != SOCK_DGRAM) 350 continue; 351 352 if (llc->laddr.lsap != laddr->lsap) 353 continue; 354 355 if (llc->dev != skb->dev) 356 continue; 357 358 skb1 = skb_clone(skb, GFP_ATOMIC); 359 if (!skb1) 360 break; 361 362 sock_hold(sk); 363 skb_set_owner_r(skb1, sk); 364 llc_sap_rcv(sap, skb1); 365 sock_put(sk); 366 } 367 read_unlock_bh(&sap->sk_list.lock); 368 } 369 370 371 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb) 372 { 373 struct llc_addr laddr; 374 375 llc_pdu_decode_da(skb, laddr.mac); 376 llc_pdu_decode_dsap(skb, &laddr.lsap); 377 378 if (llc_mac_multicast(laddr.mac)) { 379 llc_sap_mcast(sap, &laddr, skb); 380 kfree_skb(skb); 381 } else { 382 struct sock *sk = llc_lookup_dgram(sap, &laddr); 383 if (sk) { 384 skb_set_owner_r(skb, sk); 385 llc_sap_rcv(sap, skb); 386 sock_put(sk); 387 } else 388 kfree_skb(skb); 389 } 390 } 391