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