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_reserve(skb, 50); 40 skb->nh.raw = skb->h.raw = skb->data; 41 skb->protocol = htons(ETH_P_802_2); 42 skb->dev = dev; 43 skb->mac.raw = skb->head; 44 if (sk != NULL) 45 skb_set_owner_w(skb, sk); 46 } 47 return skb; 48 } 49 50 void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim) 51 { 52 struct sockaddr_llc *addr; 53 54 if (skb->sk->sk_type == SOCK_STREAM) /* See UNIX98 */ 55 return; 56 /* save primitive for use by the user. */ 57 addr = llc_ui_skb_cb(skb); 58 addr->sllc_family = sk->sk_family; 59 addr->sllc_arphrd = skb->dev->type; 60 addr->sllc_test = prim == LLC_TEST_PRIM; 61 addr->sllc_xid = prim == LLC_XID_PRIM; 62 addr->sllc_ua = prim == LLC_DATAUNIT_PRIM; 63 llc_pdu_decode_sa(skb, addr->sllc_mac); 64 llc_pdu_decode_ssap(skb, &addr->sllc_sap); 65 } 66 67 /** 68 * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu. 69 * @sap: pointer to SAP 70 * @skb: received pdu 71 */ 72 void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb) 73 { 74 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 75 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); 76 77 switch (LLC_U_PDU_RSP(pdu)) { 78 case LLC_1_PDU_CMD_TEST: 79 ev->prim = LLC_TEST_PRIM; break; 80 case LLC_1_PDU_CMD_XID: 81 ev->prim = LLC_XID_PRIM; break; 82 case LLC_1_PDU_CMD_UI: 83 ev->prim = LLC_DATAUNIT_PRIM; break; 84 } 85 ev->ind_cfm_flag = LLC_IND; 86 } 87 88 /** 89 * llc_find_sap_trans - finds transition for event 90 * @sap: pointer to SAP 91 * @skb: happened event 92 * 93 * This function finds transition that matches with happened event. 94 * Returns the pointer to found transition on success or %NULL for 95 * failure. 96 */ 97 static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap, 98 struct sk_buff* skb) 99 { 100 int i = 0; 101 struct llc_sap_state_trans *rc = NULL; 102 struct llc_sap_state_trans **next_trans; 103 struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1]; 104 /* 105 * Search thru events for this state until list exhausted or until 106 * its obvious the event is not valid for the current state 107 */ 108 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++) 109 if (!next_trans[i]->ev(sap, skb)) { 110 rc = next_trans[i]; /* got event match; return it */ 111 break; 112 } 113 return rc; 114 } 115 116 /** 117 * llc_exec_sap_trans_actions - execute actions related to event 118 * @sap: pointer to SAP 119 * @trans: pointer to transition that it's actions must be performed 120 * @skb: happened event. 121 * 122 * This function executes actions that is related to happened event. 123 * Returns 0 for success and 1 for failure of at least one action. 124 */ 125 static int llc_exec_sap_trans_actions(struct llc_sap *sap, 126 struct llc_sap_state_trans *trans, 127 struct sk_buff *skb) 128 { 129 int rc = 0; 130 llc_sap_action_t *next_action = trans->ev_actions; 131 132 for (; next_action && *next_action; next_action++) 133 if ((*next_action)(sap, skb)) 134 rc = 1; 135 return rc; 136 } 137 138 /** 139 * llc_sap_next_state - finds transition, execs actions & change SAP state 140 * @sap: pointer to SAP 141 * @skb: happened event 142 * 143 * This function finds transition that matches with happened event, then 144 * executes related actions and finally changes state of SAP. It returns 145 * 0 on success and 1 for failure. 146 */ 147 static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb) 148 { 149 int rc = 1; 150 struct llc_sap_state_trans *trans; 151 152 if (sap->state > LLC_NR_SAP_STATES) 153 goto out; 154 trans = llc_find_sap_trans(sap, skb); 155 if (!trans) 156 goto out; 157 /* 158 * Got the state to which we next transition; perform the actions 159 * associated with this transition before actually transitioning to the 160 * next state 161 */ 162 rc = llc_exec_sap_trans_actions(sap, trans, skb); 163 if (rc) 164 goto out; 165 /* 166 * Transition SAP to next state if all actions execute successfully 167 */ 168 sap->state = trans->next_state; 169 out: 170 return rc; 171 } 172 173 /** 174 * llc_sap_state_process - sends event to SAP state machine 175 * @sap: sap to use 176 * @skb: pointer to occurred event 177 * 178 * After executing actions of the event, upper layer will be indicated 179 * if needed(on receiving an UI frame). sk can be null for the 180 * datalink_proto case. 181 */ 182 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb) 183 { 184 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 185 186 /* 187 * We have to hold the skb, because llc_sap_next_state 188 * will kfree it in the sending path and we need to 189 * look at the skb->cb, where we encode llc_sap_state_ev. 190 */ 191 skb_get(skb); 192 ev->ind_cfm_flag = 0; 193 llc_sap_next_state(sap, skb); 194 if (ev->ind_cfm_flag == LLC_IND) { 195 if (skb->sk->sk_state == TCP_LISTEN) 196 kfree_skb(skb); 197 else { 198 llc_save_primitive(skb->sk, skb, ev->prim); 199 200 /* queue skb to the user. */ 201 if (sock_queue_rcv_skb(skb->sk, skb)) 202 kfree_skb(skb); 203 } 204 } 205 kfree_skb(skb); 206 } 207 208 /** 209 * llc_build_and_send_test_pkt - TEST interface for upper layers. 210 * @sap: sap to use 211 * @skb: packet to send 212 * @dmac: destination mac address 213 * @dsap: destination sap 214 * 215 * This function is called when upper layer wants to send a TEST pdu. 216 * Returns 0 for success, 1 otherwise. 217 */ 218 void llc_build_and_send_test_pkt(struct llc_sap *sap, 219 struct sk_buff *skb, u8 *dmac, u8 dsap) 220 { 221 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 222 223 ev->saddr.lsap = sap->laddr.lsap; 224 ev->daddr.lsap = dsap; 225 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); 226 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); 227 228 ev->type = LLC_SAP_EV_TYPE_PRIM; 229 ev->prim = LLC_TEST_PRIM; 230 ev->prim_type = LLC_PRIM_TYPE_REQ; 231 llc_sap_state_process(sap, skb); 232 } 233 234 /** 235 * llc_build_and_send_xid_pkt - XID interface for upper layers 236 * @sap: sap to use 237 * @skb: packet to send 238 * @dmac: destination mac address 239 * @dsap: destination sap 240 * 241 * This function is called when upper layer wants to send a XID pdu. 242 * Returns 0 for success, 1 otherwise. 243 */ 244 void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb, 245 u8 *dmac, u8 dsap) 246 { 247 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 248 249 ev->saddr.lsap = sap->laddr.lsap; 250 ev->daddr.lsap = dsap; 251 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); 252 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); 253 254 ev->type = LLC_SAP_EV_TYPE_PRIM; 255 ev->prim = LLC_XID_PRIM; 256 ev->prim_type = LLC_PRIM_TYPE_REQ; 257 llc_sap_state_process(sap, skb); 258 } 259 260 /** 261 * llc_sap_rcv - sends received pdus to the sap state machine 262 * @sap: current sap component structure. 263 * @skb: received frame. 264 * 265 * Sends received pdus to the sap state machine. 266 */ 267 static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb) 268 { 269 struct llc_sap_state_ev *ev = llc_sap_ev(skb); 270 271 ev->type = LLC_SAP_EV_TYPE_PDU; 272 ev->reason = 0; 273 llc_sap_state_process(sap, skb); 274 } 275 276 /** 277 * llc_lookup_dgram - Finds dgram socket for the local sap/mac 278 * @sap: SAP 279 * @laddr: address of local LLC (MAC + SAP) 280 * 281 * Search socket list of the SAP and finds connection using the local 282 * mac, and local sap. Returns pointer for socket found, %NULL otherwise. 283 */ 284 static struct sock *llc_lookup_dgram(struct llc_sap *sap, 285 const struct llc_addr *laddr) 286 { 287 struct sock *rc; 288 struct hlist_node *node; 289 290 read_lock_bh(&sap->sk_list.lock); 291 sk_for_each(rc, node, &sap->sk_list.list) { 292 struct llc_sock *llc = llc_sk(rc); 293 294 if (rc->sk_type == SOCK_DGRAM && 295 llc->laddr.lsap == laddr->lsap && 296 llc_mac_match(llc->laddr.mac, laddr->mac)) { 297 sock_hold(rc); 298 goto found; 299 } 300 } 301 rc = NULL; 302 found: 303 read_unlock_bh(&sap->sk_list.lock); 304 return rc; 305 } 306 307 /** 308 * llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets. 309 * @sap: SAP 310 * @laddr: address of local LLC (MAC + SAP) 311 * 312 * Search socket list of the SAP and finds connections with same sap. 313 * Deliver clone to each. 314 */ 315 static void llc_sap_mcast(struct llc_sap *sap, 316 const struct llc_addr *laddr, 317 struct sk_buff *skb) 318 { 319 struct sock *sk; 320 struct hlist_node *node; 321 322 read_lock_bh(&sap->sk_list.lock); 323 sk_for_each(sk, node, &sap->sk_list.list) { 324 struct llc_sock *llc = llc_sk(sk); 325 struct sk_buff *skb1; 326 327 if (sk->sk_type != SOCK_DGRAM) 328 continue; 329 330 if (llc->laddr.lsap != laddr->lsap) 331 continue; 332 333 skb1 = skb_clone(skb, GFP_ATOMIC); 334 if (!skb1) 335 break; 336 337 sock_hold(sk); 338 skb_set_owner_r(skb1, sk); 339 llc_sap_rcv(sap, skb1); 340 sock_put(sk); 341 } 342 read_unlock_bh(&sap->sk_list.lock); 343 } 344 345 346 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb) 347 { 348 struct llc_addr laddr; 349 350 llc_pdu_decode_da(skb, laddr.mac); 351 llc_pdu_decode_dsap(skb, &laddr.lsap); 352 353 if (llc_mac_multicast(laddr.mac)) { 354 llc_sap_mcast(sap, &laddr, skb); 355 kfree_skb(skb); 356 } else { 357 struct sock *sk = llc_lookup_dgram(sap, &laddr); 358 if (sk) { 359 skb_set_owner_r(skb, sk); 360 llc_sap_rcv(sap, skb); 361 sock_put(sk); 362 } else 363 kfree_skb(skb); 364 } 365 } 366