Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 713 insertions, 0 deletions

diff --git a/net/llc/llc_station.c b/net/llc/llc_station.c
new file mode 100644
index 000000000000..8fe48a24bad5
--- /dev/null
+++ b/net/llc/llc_station.c
@@ -0,0 +1,713 @@
+/*
+ * llc_station.c - station component of LLC
+ *
+ * Copyright (c) 1997 by Procom Technology, Inc.
+ *               2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ * This program can be redistributed or modified under the terms of the
+ * GNU General Public License as published by the Free Software Foundation.
+ * This program is distributed without any warranty or implied warranty
+ * of merchantability or fitness for a particular purpose.
+ *
+ * See the GNU General Public License for more details.
+ */
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <net/llc.h>
+#include <net/llc_sap.h>
+#include <net/llc_conn.h>
+#include <net/llc_c_ac.h>
+#include <net/llc_s_ac.h>
+#include <net/llc_c_ev.h>
+#include <net/llc_c_st.h>
+#include <net/llc_s_ev.h>
+#include <net/llc_s_st.h>
+#include <net/llc_pdu.h>
+
+/**
+ * struct llc_station - LLC station component
+ *
+ * SAP and connection resource manager, one per adapter.
+ *
+ * @state - state of station
+ * @xid_r_count - XID response PDU counter
+ * @mac_sa - MAC source address
+ * @sap_list - list of related SAPs
+ * @ev_q - events entering state mach.
+ * @mac_pdu_q - PDUs ready to send to MAC
+ */
+struct llc_station {
+        u8                          state;
+        u8                          xid_r_count;
+        struct timer_list           ack_timer;
+        u8                          retry_count;
+        u8                          maximum_retry;
+        struct {
+                struct sk_buff_head list;
+                spinlock_t          lock;
+        } ev_q;
+        struct sk_buff_head         mac_pdu_q;
+};
+
+/* Types of events (possible values in 'ev->type') */
+#define LLC_STATION_EV_TYPE_SIMPLE      1
+#define LLC_STATION_EV_TYPE_CONDITION   2
+#define LLC_STATION_EV_TYPE_PRIM        3
+#define LLC_STATION_EV_TYPE_PDU         4       /* command/response PDU */
+#define LLC_STATION_EV_TYPE_ACK_TMR     5
+#define LLC_STATION_EV_TYPE_RPT_STATUS  6
+
+/* Events */
+#define LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK               1
+#define LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK            2
+#define LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY       3
+#define LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY       4
+#define LLC_STATION_EV_RX_NULL_DSAP_XID_C                       5
+#define LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ        6
+#define LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ        7
+#define LLC_STATION_EV_RX_NULL_DSAP_TEST_C                      8
+#define LLC_STATION_EV_DISABLE_REQ                              9
+
+struct llc_station_state_ev {
+        u8               type;
+        u8               prim;
+        u8               prim_type;
+        u8               reason;
+        struct list_head node; /* node in station->ev_q.list */
+};
+
+static __inline__ struct llc_station_state_ev *
+                                        llc_station_ev(struct sk_buff *skb)
+{
+        return (struct llc_station_state_ev *)skb->cb;
+}
+
+typedef int (*llc_station_ev_t)(struct sk_buff *skb);
+
+#define LLC_STATION_STATE_DOWN          1       /* initial state */
+#define LLC_STATION_STATE_DUP_ADDR_CHK  2
+#define LLC_STATION_STATE_UP            3
+
+#define LLC_NBR_STATION_STATES          3       /* size of state table */
+
+typedef int (*llc_station_action_t)(struct sk_buff *skb);
+
+/* Station component state table structure */
+struct llc_station_state_trans {
+        llc_station_ev_t ev;
+        u8 next_state;
+        llc_station_action_t *ev_actions;
+};
+
+struct llc_station_state {
+        u8 curr_state;
+        struct llc_station_state_trans **transitions;
+};
+
+static struct llc_station llc_main_station;
+
+static int llc_stat_ev_enable_with_dup_addr_check(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);  
+        
+        return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
+               ev->prim_type ==
+                              LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK ? 0 : 1;
+}
+
+static int llc_stat_ev_enable_without_dup_addr_check(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);  
+        
+        return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
+               ev->prim_type ==
+                        LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK ? 0 : 1;
+}
+
+static int llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);  
+        
+        return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
+                llc_main_station.retry_count <
+                llc_main_station.maximum_retry ? 0 : 1;
+}
+
+static int llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);  
+        
+        return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
+                llc_main_station.retry_count ==
+                llc_main_station.maximum_retry ? 0 : 1;
+}
+
+static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);  
+        struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+        return ev->type == LLC_STATION_EV_TYPE_PDU &&
+               LLC_PDU_IS_CMD(pdu) &&                   /* command PDU */
+               LLC_PDU_TYPE_IS_U(pdu) &&                /* U type PDU */
+               LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
+               !pdu->dsap ? 0 : 1;                      /* NULL DSAP value */
+}
+
+static int llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);
+        struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+        return ev->type == LLC_STATION_EV_TYPE_PDU &&
+               LLC_PDU_IS_RSP(pdu) &&                   /* response PDU */
+               LLC_PDU_TYPE_IS_U(pdu) &&                /* U type PDU */
+               LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
+               !pdu->dsap &&                            /* NULL DSAP value */
+               !llc_main_station.xid_r_count ? 0 : 1;
+}
+
+static int llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);
+        struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+        return ev->type == LLC_STATION_EV_TYPE_PDU &&
+               LLC_PDU_IS_RSP(pdu) &&                   /* response PDU */
+               LLC_PDU_TYPE_IS_U(pdu) &&                /* U type PDU */
+               LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
+               !pdu->dsap &&                            /* NULL DSAP value */
+               llc_main_station.xid_r_count == 1 ? 0 : 1;
+}
+
+static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);
+        struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+        return ev->type == LLC_STATION_EV_TYPE_PDU &&
+               LLC_PDU_IS_CMD(pdu) &&                   /* command PDU */
+               LLC_PDU_TYPE_IS_U(pdu) &&                /* U type PDU */
+               LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
+               !pdu->dsap ? 0 : 1;                      /* NULL DSAP */
+}
+
+static int llc_stat_ev_disable_req(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);
+
+        return ev->type == LLC_STATION_EV_TYPE_PRIM &&
+               ev->prim == LLC_DISABLE_PRIM &&
+               ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
+}
+
+/**
+ *      llc_station_send_pdu - queues PDU to send
+ *      @skb: Address of the PDU
+ *
+ *      Queues a PDU to send to the MAC layer.
+ */
+static void llc_station_send_pdu(struct sk_buff *skb)
+{
+        skb_queue_tail(&llc_main_station.mac_pdu_q, skb);
+        while ((skb = skb_dequeue(&llc_main_station.mac_pdu_q)) != NULL)
+                if (dev_queue_xmit(skb))
+                        break;
+}
+
+static int llc_station_ac_start_ack_timer(struct sk_buff *skb)
+{
+        mod_timer(&llc_main_station.ack_timer, jiffies + LLC_ACK_TIME * HZ);
+        return 0;
+}
+
+static int llc_station_ac_set_retry_cnt_0(struct sk_buff *skb)
+{
+        llc_main_station.retry_count = 0;
+        return 0;
+}
+
+static int llc_station_ac_inc_retry_cnt_by_1(struct sk_buff *skb)
+{
+        llc_main_station.retry_count++;
+        return 0;
+}
+
+static int llc_station_ac_set_xid_r_cnt_0(struct sk_buff *skb)
+{
+        llc_main_station.xid_r_count = 0;
+        return 0;
+}
+
+static int llc_station_ac_inc_xid_r_cnt_by_1(struct sk_buff *skb)
+{
+        llc_main_station.xid_r_count++;
+        return 0;
+}
+
+static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb)
+{
+        int rc = 1;
+        struct sk_buff *nskb = llc_alloc_frame();
+
+        if (!nskb)
+                goto out;
+        llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, 0, LLC_PDU_CMD);
+        llc_pdu_init_as_xid_cmd(nskb, LLC_XID_NULL_CLASS_2, 127);
+        rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, llc_station_mac_sa);
+        if (rc)
+                goto free;
+        llc_station_send_pdu(nskb);
+out:
+        return rc;
+free:
+        kfree_skb(skb);
+        goto out;
+}
+
+static int llc_station_ac_send_xid_r(struct sk_buff *skb)
+{
+        u8 mac_da[ETH_ALEN], dsap;
+        int rc = 1;
+        struct sk_buff* nskb = llc_alloc_frame();
+
+        if (!nskb)
+                goto out;
+        rc = 0;
+        nskb->dev = skb->dev;
+        llc_pdu_decode_sa(skb, mac_da);
+        llc_pdu_decode_ssap(skb, &dsap);
+        llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
+        llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
+        rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
+        if (rc)
+                goto free;
+        llc_station_send_pdu(nskb);
+out:
+        return rc;
+free:
+        kfree_skb(skb);
+        goto out;
+}
+
+static int llc_station_ac_send_test_r(struct sk_buff *skb)
+{
+        u8 mac_da[ETH_ALEN], dsap;
+        int rc = 1;
+        struct sk_buff *nskb = llc_alloc_frame();
+
+        if (!nskb)
+                goto out;
+        rc = 0;
+        nskb->dev = skb->dev;
+        llc_pdu_decode_sa(skb, mac_da);
+        llc_pdu_decode_ssap(skb, &dsap);
+        llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
+        llc_pdu_init_as_test_rsp(nskb, skb);
+        rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
+        if (rc)
+                goto free;
+        llc_station_send_pdu(nskb);
+out:
+        return rc;
+free:
+        kfree_skb(skb);
+        goto out;
+}
+
+static int llc_station_ac_report_status(struct sk_buff *skb)
+{
+        return 0;
+}
+
+/* COMMON STATION STATE transitions */
+
+/* dummy last-transition indicator; common to all state transition groups
+ * last entry for this state
+ * all members are zeros, .bss zeroes it
+ */
+static struct llc_station_state_trans llc_stat_state_trans_end;
+
+/* DOWN STATE transitions */
+
+/* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */
+static llc_station_action_t llc_stat_down_state_actions_1[] = {
+        [0] = llc_station_ac_start_ack_timer,
+        [1] = llc_station_ac_set_retry_cnt_0,
+        [2] = llc_station_ac_set_xid_r_cnt_0,
+        [3] = llc_station_ac_send_null_dsap_xid_c,
+        [4] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_down_state_trans_1 = {
+        .ev         = llc_stat_ev_enable_with_dup_addr_check,
+        .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
+        .ev_actions = llc_stat_down_state_actions_1,
+};
+
+/* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */
+static llc_station_action_t llc_stat_down_state_actions_2[] = {
+        [0] = llc_station_ac_report_status,     /* STATION UP */
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_down_state_trans_2 = {
+        .ev         = llc_stat_ev_enable_without_dup_addr_check,
+        .next_state = LLC_STATION_STATE_UP,
+        .ev_actions = llc_stat_down_state_actions_2,
+};
+
+/* array of pointers; one to each transition */
+static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = {
+        [0] = &llc_stat_down_state_trans_1,
+        [1] = &llc_stat_down_state_trans_2,
+        [2] = &llc_stat_state_trans_end,
+};
+
+/* UP STATE transitions */
+/* state transition for LLC_STATION_EV_DISABLE_REQ event */
+static llc_station_action_t llc_stat_up_state_actions_1[] = {
+        [0] = llc_station_ac_report_status,     /* STATION DOWN */
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_up_state_trans_1 = {
+        .ev         = llc_stat_ev_disable_req,
+        .next_state = LLC_STATION_STATE_DOWN,
+        .ev_actions = llc_stat_up_state_actions_1,
+};
+
+/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
+static llc_station_action_t llc_stat_up_state_actions_2[] = {
+        [0] = llc_station_ac_send_xid_r,
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
+        .ev         = llc_stat_ev_rx_null_dsap_xid_c,
+        .next_state = LLC_STATION_STATE_UP,
+        .ev_actions = llc_stat_up_state_actions_2,
+};
+
+/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
+static llc_station_action_t llc_stat_up_state_actions_3[] = {
+        [0] = llc_station_ac_send_test_r,
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
+        .ev         = llc_stat_ev_rx_null_dsap_test_c,
+        .next_state = LLC_STATION_STATE_UP,
+        .ev_actions = llc_stat_up_state_actions_3,
+};
+
+/* array of pointers; one to each transition */
+static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
+        [0] = &llc_stat_up_state_trans_1,
+        [1] = &llc_stat_up_state_trans_2,
+        [2] = &llc_stat_up_state_trans_3,
+        [3] = &llc_stat_state_trans_end,
+};
+
+/* DUP ADDR CHK STATE transitions */
+/* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ
+ * event
+ */
+static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = {
+        [0] = llc_station_ac_inc_xid_r_cnt_by_1,
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = {
+        .ev         = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq,
+        .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
+        .ev_actions = llc_stat_dupaddr_state_actions_1,
+};
+
+/* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ
+ * event
+ */
+static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = {
+        [0] = llc_station_ac_report_status,     /* DUPLICATE ADDRESS FOUND */
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = {
+        .ev         = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq,
+        .next_state = LLC_STATION_STATE_DOWN,
+        .ev_actions = llc_stat_dupaddr_state_actions_2,
+};
+
+/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
+static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = {
+        [0] = llc_station_ac_send_xid_r,
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = {
+        .ev         = llc_stat_ev_rx_null_dsap_xid_c,
+        .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
+        .ev_actions = llc_stat_dupaddr_state_actions_3,
+};
+
+/* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY
+ * event
+ */
+static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = {
+        [0] = llc_station_ac_start_ack_timer,
+        [1] = llc_station_ac_inc_retry_cnt_by_1,
+        [2] = llc_station_ac_set_xid_r_cnt_0,
+        [3] = llc_station_ac_send_null_dsap_xid_c,
+        [4] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = {
+        .ev         = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry,
+        .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
+        .ev_actions = llc_stat_dupaddr_state_actions_4,
+};
+
+/* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY
+ * event
+ */
+static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = {
+        [0] = llc_station_ac_report_status,     /* STATION UP */
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = {
+        .ev         = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry,
+        .next_state = LLC_STATION_STATE_UP,
+        .ev_actions = llc_stat_dupaddr_state_actions_5,
+};
+
+/* state transition for LLC_STATION_EV_DISABLE_REQ event */
+static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = {
+        [0] = llc_station_ac_report_status,     /* STATION DOWN */
+        [1] = NULL,
+};
+
+static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = {
+        .ev         = llc_stat_ev_disable_req,
+        .next_state = LLC_STATION_STATE_DOWN,
+        .ev_actions = llc_stat_dupaddr_state_actions_6,
+};
+
+/* array of pointers; one to each transition */
+static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = {
+        [0] = &llc_stat_dupaddr_state_trans_6,  /* Request */
+        [1] = &llc_stat_dupaddr_state_trans_4,  /* Timer */
+        [2] = &llc_stat_dupaddr_state_trans_5,
+        [3] = &llc_stat_dupaddr_state_trans_1,  /* Receive frame */
+        [4] = &llc_stat_dupaddr_state_trans_2,
+        [5] = &llc_stat_dupaddr_state_trans_3,
+        [6] = &llc_stat_state_trans_end,
+};
+
+static struct llc_station_state
+                        llc_station_state_table[LLC_NBR_STATION_STATES] = {
+        [LLC_STATION_STATE_DOWN - 1] = {
+                .curr_state  = LLC_STATION_STATE_DOWN,
+                .transitions = llc_stat_dwn_state_trans,
+        },
+        [LLC_STATION_STATE_DUP_ADDR_CHK - 1] = {
+                .curr_state  = LLC_STATION_STATE_DUP_ADDR_CHK,
+                .transitions = llc_stat_dupaddr_state_trans,
+        },
+        [LLC_STATION_STATE_UP - 1] = {
+                .curr_state  = LLC_STATION_STATE_UP,
+                .transitions = llc_stat_up_state_trans,
+        },
+};
+
+/**
+ *      llc_exec_station_trans_actions - executes actions for transition
+ *      @trans: Address of the transition
+ *      @skb: Address of the event that caused the transition
+ *
+ *      Executes actions of a transition of the station state machine. Returns
+ *      0 if all actions complete successfully, nonzero otherwise.
+ */
+static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
+                                          struct sk_buff *skb)
+{
+        u16 rc = 0;
+        llc_station_action_t *next_action = trans->ev_actions;
+
+        for (; next_action && *next_action; next_action++)
+                if ((*next_action)(skb))
+                        rc = 1;
+        return rc;
+}
+
+/**
+ *      llc_find_station_trans - finds transition for this event
+ *      @skb: Address of the event
+ *
+ *      Search thru events of the current state of the station until list
+ *      exhausted or it's obvious that the event is not valid for the current
+ *      state. Returns the address of the transition if cound, %NULL otherwise.
+ */
+static struct llc_station_state_trans *
+                                llc_find_station_trans(struct sk_buff *skb)
+{
+        int i = 0;
+        struct llc_station_state_trans *rc = NULL;
+        struct llc_station_state_trans **next_trans;
+        struct llc_station_state *curr_state =
+                                &llc_station_state_table[llc_main_station.state - 1];
+
+        for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
+                if (!next_trans[i]->ev(skb)) {
+                        rc = next_trans[i];
+                        break;
+                }
+        return rc;
+}
+
+/**
+ *      llc_station_free_ev - frees an event
+ *      @skb: Address of the event
+ *
+ *      Frees an event.
+ */
+static void llc_station_free_ev(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);
+
+        if (ev->type == LLC_STATION_EV_TYPE_PDU)
+                kfree_skb(skb);
+}
+
+/**
+ *      llc_station_next_state - processes event and goes to the next state
+ *      @skb: Address of the event
+ *
+ *      Processes an event, executes any transitions related to that event and
+ *      updates the state of the station.
+ */
+static u16 llc_station_next_state(struct sk_buff *skb)
+{
+        u16 rc = 1;
+        struct llc_station_state_trans *trans;
+
+        if (llc_main_station.state > LLC_NBR_STATION_STATES)
+                goto out;
+        trans = llc_find_station_trans(skb);
+        if (trans) {
+                /* got the state to which we next transition; perform the
+                 * actions associated with this transition before actually
+                 * transitioning to the next state
+                 */
+                rc = llc_exec_station_trans_actions(trans, skb);
+                if (!rc)
+                        /* transition station to next state if all actions
+                         * execute successfully; done; wait for next event
+                         */
+                        llc_main_station.state = trans->next_state;
+        } else
+                /* event not recognized in current state; re-queue it for
+                 * processing again at a later time; return failure
+                 */
+                rc = 0;
+out:
+        llc_station_free_ev(skb);
+        return rc;
+}
+
+/**
+ *      llc_station_service_events - service events in the queue
+ *
+ *      Get an event from the station event queue (if any); attempt to service
+ *      the event; if event serviced, get the next event (if any) on the event
+ *      queue; if event not service, re-queue the event on the event queue and
+ *      attempt to service the next event; when serviced all events in queue,
+ *      finished; if don't transition to different state, just service all
+ *      events once; if transition to new state, service all events again.
+ *      Caller must hold llc_main_station.ev_q.lock.
+ */
+static void llc_station_service_events(void)
+{
+        struct sk_buff *skb;
+
+        while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL)
+                llc_station_next_state(skb);
+}
+
+/**
+ *      llc_station_state_process: queue event and try to process queue.
+ *      @skb: Address of the event
+ *
+ *      Queues an event (on the station event queue) for handling by the
+ *      station state machine and attempts to process any queued-up events.
+ */
+static void llc_station_state_process(struct sk_buff *skb)
+{
+        spin_lock_bh(&llc_main_station.ev_q.lock);
+        skb_queue_tail(&llc_main_station.ev_q.list, skb);
+        llc_station_service_events();
+        spin_unlock_bh(&llc_main_station.ev_q.lock);
+}
+
+static void llc_station_ack_tmr_cb(unsigned long timeout_data)
+{
+        struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
+
+        if (skb) {
+                struct llc_station_state_ev *ev = llc_station_ev(skb);
+
+                ev->type = LLC_STATION_EV_TYPE_ACK_TMR;
+                llc_station_state_process(skb);
+        }
+}
+
+/*
+ *      llc_station_rcv - send received pdu to the station state machine
+ *      @skb: received frame.
+ *
+ *      Sends data unit to station state machine.
+ */
+static void llc_station_rcv(struct sk_buff *skb)
+{
+        struct llc_station_state_ev *ev = llc_station_ev(skb);
+
+        ev->type   = LLC_STATION_EV_TYPE_PDU;
+        ev->reason = 0;
+        llc_station_state_process(skb);
+}
+
+int __init llc_station_init(void)
+{
+        u16 rc = -ENOBUFS;
+        struct sk_buff *skb;
+        struct llc_station_state_ev *ev;
+
+        skb_queue_head_init(&llc_main_station.mac_pdu_q);
+        skb_queue_head_init(&llc_main_station.ev_q.list);
+        spin_lock_init(&llc_main_station.ev_q.lock);
+        init_timer(&llc_main_station.ack_timer);
+        llc_main_station.ack_timer.data     = (unsigned long)&llc_main_station;
+        llc_main_station.ack_timer.function = llc_station_ack_tmr_cb;
+
+        skb = alloc_skb(0, GFP_ATOMIC);
+        if (!skb)
+                goto out;
+        rc = 0;
+        llc_set_station_handler(llc_station_rcv);
+        ev = llc_station_ev(skb);
+        memset(ev, 0, sizeof(*ev));
+        llc_main_station.ack_timer.expires = jiffies + 3 * HZ;
+        llc_main_station.maximum_retry  = 1;
+        llc_main_station.state          = LLC_STATION_STATE_DOWN;
+        ev->type        = LLC_STATION_EV_TYPE_SIMPLE;
+        ev->prim_type   = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK;
+        rc = llc_station_next_state(skb);
+out:
+        return rc;
+}
+
+void __exit llc_station_exit(void)
+{
+        llc_set_station_handler(NULL);
+}