2 * llc_sap.c - driver routines for SAP component.
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
12 * See the GNU General Public License for more details.
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>
24 #include <net/tcp_states.h>
25 #include <linux/llc.h>
28 * llc_alloc_frame - allocates sk_buff for frame
29 * @dev: network device this skb will be sent over
31 * Allocates an sk_buff for frame and initializes sk_buff fields.
32 * Returns allocated skb or %NULL when out of memory.
34 struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev)
36 struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC);
40 skb->nh.raw = skb->h.raw = skb->data;
41 skb->protocol = htons(ETH_P_802_2);
43 skb->mac.raw = skb->head;
45 skb_set_owner_w(skb, sk);
50 void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim)
52 struct sockaddr_llc *addr = llc_ui_skb_cb(skb);
54 /* save primitive for use by the user. */
55 addr->sllc_family = sk->sk_family;
56 addr->sllc_arphrd = skb->dev->type;
57 addr->sllc_test = prim == LLC_TEST_PRIM;
58 addr->sllc_xid = prim == LLC_XID_PRIM;
59 addr->sllc_ua = prim == LLC_DATAUNIT_PRIM;
60 llc_pdu_decode_sa(skb, addr->sllc_mac);
61 llc_pdu_decode_ssap(skb, &addr->sllc_sap);
65 * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
66 * @sap: pointer to SAP
69 void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb)
71 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
72 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
74 switch (LLC_U_PDU_RSP(pdu)) {
75 case LLC_1_PDU_CMD_TEST:
76 ev->prim = LLC_TEST_PRIM; break;
77 case LLC_1_PDU_CMD_XID:
78 ev->prim = LLC_XID_PRIM; break;
79 case LLC_1_PDU_CMD_UI:
80 ev->prim = LLC_DATAUNIT_PRIM; break;
82 ev->ind_cfm_flag = LLC_IND;
86 * llc_find_sap_trans - finds transition for event
87 * @sap: pointer to SAP
88 * @skb: happened event
90 * This function finds transition that matches with happened event.
91 * Returns the pointer to found transition on success or %NULL for
94 static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
98 struct llc_sap_state_trans *rc = NULL;
99 struct llc_sap_state_trans **next_trans;
100 struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
102 * Search thru events for this state until list exhausted or until
103 * its obvious the event is not valid for the current state
105 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
106 if (!next_trans[i]->ev(sap, skb)) {
107 rc = next_trans[i]; /* got event match; return it */
114 * llc_exec_sap_trans_actions - execute actions related to event
115 * @sap: pointer to SAP
116 * @trans: pointer to transition that it's actions must be performed
117 * @skb: happened event.
119 * This function executes actions that is related to happened event.
120 * Returns 0 for success and 1 for failure of at least one action.
122 static int llc_exec_sap_trans_actions(struct llc_sap *sap,
123 struct llc_sap_state_trans *trans,
127 llc_sap_action_t *next_action = trans->ev_actions;
129 for (; next_action && *next_action; next_action++)
130 if ((*next_action)(sap, skb))
136 * llc_sap_next_state - finds transition, execs actions & change SAP state
137 * @sap: pointer to SAP
138 * @skb: happened event
140 * This function finds transition that matches with happened event, then
141 * executes related actions and finally changes state of SAP. It returns
142 * 0 on success and 1 for failure.
144 static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
147 struct llc_sap_state_trans *trans;
149 if (sap->state > LLC_NR_SAP_STATES)
151 trans = llc_find_sap_trans(sap, skb);
155 * Got the state to which we next transition; perform the actions
156 * associated with this transition before actually transitioning to the
159 rc = llc_exec_sap_trans_actions(sap, trans, skb);
163 * Transition SAP to next state if all actions execute successfully
165 sap->state = trans->next_state;
171 * llc_sap_state_process - sends event to SAP state machine
173 * @skb: pointer to occurred event
175 * After executing actions of the event, upper layer will be indicated
176 * if needed(on receiving an UI frame). sk can be null for the
177 * datalink_proto case.
179 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
181 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
184 * We have to hold the skb, because llc_sap_next_state
185 * will kfree it in the sending path and we need to
186 * look at the skb->cb, where we encode llc_sap_state_ev.
189 ev->ind_cfm_flag = 0;
190 llc_sap_next_state(sap, skb);
191 if (ev->ind_cfm_flag == LLC_IND) {
192 if (skb->sk->sk_state == TCP_LISTEN)
195 llc_save_primitive(skb->sk, skb, ev->prim);
197 /* queue skb to the user. */
198 if (sock_queue_rcv_skb(skb->sk, skb))
206 * llc_build_and_send_test_pkt - TEST interface for upper layers.
208 * @skb: packet to send
209 * @dmac: destination mac address
210 * @dsap: destination sap
212 * This function is called when upper layer wants to send a TEST pdu.
213 * Returns 0 for success, 1 otherwise.
215 void llc_build_and_send_test_pkt(struct llc_sap *sap,
216 struct sk_buff *skb, u8 *dmac, u8 dsap)
218 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
220 ev->saddr.lsap = sap->laddr.lsap;
221 ev->daddr.lsap = dsap;
222 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
223 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
225 ev->type = LLC_SAP_EV_TYPE_PRIM;
226 ev->prim = LLC_TEST_PRIM;
227 ev->prim_type = LLC_PRIM_TYPE_REQ;
228 llc_sap_state_process(sap, skb);
232 * llc_build_and_send_xid_pkt - XID interface for upper layers
234 * @skb: packet to send
235 * @dmac: destination mac address
236 * @dsap: destination sap
238 * This function is called when upper layer wants to send a XID pdu.
239 * Returns 0 for success, 1 otherwise.
241 void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
244 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
246 ev->saddr.lsap = sap->laddr.lsap;
247 ev->daddr.lsap = dsap;
248 memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
249 memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
251 ev->type = LLC_SAP_EV_TYPE_PRIM;
252 ev->prim = LLC_XID_PRIM;
253 ev->prim_type = LLC_PRIM_TYPE_REQ;
254 llc_sap_state_process(sap, skb);
258 * llc_sap_rcv - sends received pdus to the sap state machine
259 * @sap: current sap component structure.
260 * @skb: received frame.
262 * Sends received pdus to the sap state machine.
264 static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb)
266 struct llc_sap_state_ev *ev = llc_sap_ev(skb);
268 ev->type = LLC_SAP_EV_TYPE_PDU;
270 llc_sap_state_process(sap, skb);
274 * llc_lookup_dgram - Finds dgram socket for the local sap/mac
276 * @laddr: address of local LLC (MAC + SAP)
278 * Search socket list of the SAP and finds connection using the local
279 * mac, and local sap. Returns pointer for socket found, %NULL otherwise.
281 static struct sock *llc_lookup_dgram(struct llc_sap *sap,
282 struct llc_addr *laddr)
285 struct hlist_node *node;
287 read_lock_bh(&sap->sk_list.lock);
288 sk_for_each(rc, node, &sap->sk_list.list) {
289 struct llc_sock *llc = llc_sk(rc);
291 if (rc->sk_type == SOCK_DGRAM &&
292 llc->laddr.lsap == laddr->lsap &&
293 llc_mac_match(llc->laddr.mac, laddr->mac)) {
300 read_unlock_bh(&sap->sk_list.lock);
304 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
306 struct llc_addr laddr;
309 llc_pdu_decode_da(skb, laddr.mac);
310 llc_pdu_decode_dsap(skb, &laddr.lsap);
312 sk = llc_lookup_dgram(sap, &laddr);
314 skb_set_owner_r(skb, sk);
315 llc_sap_rcv(sap, skb);