Logo Search packages:      
Sourcecode: linux version File versions  Download package

llc_conn.c

/*
 * llc_conn.c - Driver routines for connection component.
 *
 * 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/init.h>
#include <net/llc_sap.h>
#include <net/llc_conn.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_st.h>
#include <net/llc_pdu.h>

#if 0
#define dprintk(args...) printk(KERN_DEBUG args)
#else
#define dprintk(args...)
#endif

static int llc_find_offset(int state, int ev_type);
static void llc_conn_send_pdus(struct sock *sk);
static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
static int llc_exec_conn_trans_actions(struct sock *sk,
                               struct llc_conn_state_trans *trans,
                               struct sk_buff *ev);
static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
                                          struct sk_buff *skb);

/* Offset table on connection states transition diagram */
static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];

int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;

/**
 *    llc_conn_state_process - sends event to connection state machine
 *    @sk: connection
 *    @skb: occurred event
 *
 *    Sends an event to connection state machine. After processing event
 *    (executing it's actions and changing state), upper layer will be
 *    indicated or confirmed, if needed. Returns 0 for success, 1 for
 *    failure. The socket lock has to be held before calling this function.
 */
int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
{
      int rc;
      struct llc_sock *llc = llc_sk(skb->sk);
      struct llc_conn_state_ev *ev = llc_conn_ev(skb);

      /*
       * We have to hold the skb, because llc_conn_service will kfree it in
       * the sending path and we need to look at the skb->cb, where we encode
       * llc_conn_state_ev.
       */
      skb_get(skb);
      ev->ind_prim = ev->cfm_prim = 0;
      /*
       * Send event to state machine
       */
      rc = llc_conn_service(skb->sk, skb);
      if (unlikely(rc != 0)) {
            printk(KERN_ERR "%s: llc_conn_service failed\n", __FUNCTION__);
            goto out_kfree_skb;
      }

      if (unlikely(!ev->ind_prim && !ev->cfm_prim)) {
            /* indicate or confirm not required */
            /* XXX this is not very pretty, perhaps we should store
             * XXX indicate/confirm-needed state in the llc_conn_state_ev
             * XXX control block of the SKB instead? -DaveM
             */
            if (!skb->next)
                  goto out_kfree_skb;
            goto out_skb_put;
      }

      if (unlikely(ev->ind_prim && ev->cfm_prim)) /* Paranoia */
            skb_get(skb);

      switch (ev->ind_prim) {
      case LLC_DATA_PRIM:
            llc_save_primitive(sk, skb, LLC_DATA_PRIM);
            if (unlikely(sock_queue_rcv_skb(sk, skb))) {
                  /*
                   * shouldn't happen
                   */
                  printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
                         __FUNCTION__);
                  kfree_skb(skb);
            }
            break;
      case LLC_CONN_PRIM:
            /*
             * Can't be sock_queue_rcv_skb, because we have to leave the
             * skb->sk pointing to the newly created struct sock in
             * llc_conn_handler. -acme
             */
            skb_queue_tail(&sk->sk_receive_queue, skb);
            sk->sk_state_change(sk);
            break;
      case LLC_DISC_PRIM:
            sock_hold(sk);
            if (sk->sk_type == SOCK_STREAM &&
                sk->sk_state == TCP_ESTABLISHED) {
                  sk->sk_shutdown       = SHUTDOWN_MASK;
                  sk->sk_socket->state  = SS_UNCONNECTED;
                  sk->sk_state          = TCP_CLOSE;
                  if (!sock_flag(sk, SOCK_DEAD)) {
                        sock_set_flag(sk, SOCK_DEAD);
                        sk->sk_state_change(sk);
                  }
            }
            kfree_skb(skb);
            sock_put(sk);
            break;
      case LLC_RESET_PRIM:
            /*
             * FIXME:
             * RESET is not being notified to upper layers for now
             */
            printk(KERN_INFO "%s: received a reset ind!\n", __FUNCTION__);
            kfree_skb(skb);
            break;
      default:
            if (ev->ind_prim) {
                  printk(KERN_INFO "%s: received unknown %d prim!\n",
                        __FUNCTION__, ev->ind_prim);
                  kfree_skb(skb);
            }
            /* No indication */
            break;
      }

      switch (ev->cfm_prim) {
      case LLC_DATA_PRIM:
            if (!llc_data_accept_state(llc->state))
                  sk->sk_write_space(sk);
            else
                  rc = llc->failed_data_req = 1;
            break;
      case LLC_CONN_PRIM:
            if (sk->sk_type == SOCK_STREAM &&
                sk->sk_state == TCP_SYN_SENT) {
                  if (ev->status) {
                        sk->sk_socket->state = SS_UNCONNECTED;
                        sk->sk_state         = TCP_CLOSE;
                  } else {
                        sk->sk_socket->state = SS_CONNECTED;
                        sk->sk_state         = TCP_ESTABLISHED;
                  }
                  sk->sk_state_change(sk);
            }
            break;
      case LLC_DISC_PRIM:
            sock_hold(sk);
            if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
                  sk->sk_socket->state = SS_UNCONNECTED;
                  sk->sk_state         = TCP_CLOSE;
                  sk->sk_state_change(sk);
            }
            sock_put(sk);
            break;
      case LLC_RESET_PRIM:
            /*
             * FIXME:
             * RESET is not being notified to upper layers for now
             */
            printk(KERN_INFO "%s: received a reset conf!\n", __FUNCTION__);
            break;
      default:
            if (ev->cfm_prim) {
                  printk(KERN_INFO "%s: received unknown %d prim!\n",
                              __FUNCTION__, ev->cfm_prim);
                  break;
            }
            goto out_skb_put; /* No confirmation */
      }
out_kfree_skb:
      kfree_skb(skb);
out_skb_put:
      kfree_skb(skb);
      return rc;
}

void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
{
      /* queue PDU to send to MAC layer */
      skb_queue_tail(&sk->sk_write_queue, skb);
      llc_conn_send_pdus(sk);
}

/**
 *    llc_conn_rtn_pdu - sends received data pdu to upper layer
 *    @sk: Active connection
 *    @skb: Received data frame
 *
 *    Sends received data pdu to upper layer (by using indicate function).
 *    Prepares service parameters (prim and prim_data). calling indication
 *    function will be done in llc_conn_state_process.
 */
void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
{
      struct llc_conn_state_ev *ev = llc_conn_ev(skb);

      ev->ind_prim = LLC_DATA_PRIM;
}

/**
 *    llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
 *    @sk: active connection
 *    @nr: NR
 *    @first_p_bit: p_bit value of first pdu
 *
 *    Resend all unacknowledged I PDUs, starting with the NR; send first as
 *    command PDU with P bit equal first_p_bit; if more than one send
 *    subsequent as command PDUs with P bit equal zero (0).
 */
void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
{
      struct sk_buff *skb;
      struct llc_pdu_sn *pdu;
      u16 nbr_unack_pdus;
      struct llc_sock *llc;
      u8 howmany_resend = 0;

      llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
      if (!nbr_unack_pdus)
            goto out;
      /*
       * Process unack PDUs only if unack queue is not empty; remove
       * appropriate PDUs, fix them up, and put them on mac_pdu_q.
       */
      llc = llc_sk(sk);

      while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
            pdu = llc_pdu_sn_hdr(skb);
            llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
            llc_pdu_set_pf_bit(skb, first_p_bit);
            skb_queue_tail(&sk->sk_write_queue, skb);
            first_p_bit = 0;
            llc->vS = LLC_I_GET_NS(pdu);
            howmany_resend++;
      }
      if (howmany_resend > 0)
            llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
      /* any PDUs to re-send are queued up; start sending to MAC */
      llc_conn_send_pdus(sk);
out:;
}

/**
 *    llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
 *    @sk: active connection.
 *    @nr: NR
 *    @first_f_bit: f_bit value of first pdu.
 *
 *    Resend all unacknowledged I PDUs, starting with the NR; send first as
 *    response PDU with F bit equal first_f_bit; if more than one send
 *    subsequent as response PDUs with F bit equal zero (0).
 */
void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
{
      struct sk_buff *skb;
      u16 nbr_unack_pdus;
      struct llc_sock *llc = llc_sk(sk);
      u8 howmany_resend = 0;

      llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
      if (!nbr_unack_pdus)
            goto out;
      /*
       * Process unack PDUs only if unack queue is not empty; remove
       * appropriate PDUs, fix them up, and put them on mac_pdu_q
       */
      while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
            struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

            llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
            llc_pdu_set_pf_bit(skb, first_f_bit);
            skb_queue_tail(&sk->sk_write_queue, skb);
            first_f_bit = 0;
            llc->vS = LLC_I_GET_NS(pdu);
            howmany_resend++;
      }
      if (howmany_resend > 0)
            llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
      /* any PDUs to re-send are queued up; start sending to MAC */
      llc_conn_send_pdus(sk);
out:;
}

/**
 *    llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
 *    @sk: active connection
 *    nr: NR
 *    how_many_unacked: size of pdu_unack_q after removing acked pdus
 *
 *    Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
 *    the number of pdus that removed from queue.
 */
int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
{
      int pdu_pos, i;
      struct sk_buff *skb;
      struct llc_pdu_sn *pdu;
      int nbr_acked = 0;
      struct llc_sock *llc = llc_sk(sk);
      int q_len = skb_queue_len(&llc->pdu_unack_q);

      if (!q_len)
            goto out;
      skb = skb_peek(&llc->pdu_unack_q);
      pdu = llc_pdu_sn_hdr(skb);

      /* finding position of last acked pdu in queue */
      pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
                  (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;

      for (i = 0; i < pdu_pos && i < q_len; i++) {
            skb = skb_dequeue(&llc->pdu_unack_q);
            if (skb)
                  kfree_skb(skb);
            nbr_acked++;
      }
out:
      *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
      return nbr_acked;
}

/**
 *    llc_conn_send_pdus - Sends queued PDUs
 *    @sk: active connection
 *
 *    Sends queued pdus to MAC layer for transmission.
 */
static void llc_conn_send_pdus(struct sock *sk)
{
      struct sk_buff *skb;

      while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
            struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

            if (LLC_PDU_TYPE_IS_I(pdu) &&
                !(skb->dev->flags & IFF_LOOPBACK)) {
                  struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);

                  skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
                  if (!skb2)
                        break;
                  skb = skb2;
            }
            dev_queue_xmit(skb);
      }
}

/**
 *    llc_conn_service - finds transition and changes state of connection
 *    @sk: connection
 *    @skb: happened event
 *
 *    This function finds transition that matches with happened event, then
 *    executes related actions and finally changes state of connection.
 *    Returns 0 for success, 1 for failure.
 */
static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
{
      int rc = 1;
      struct llc_sock *llc = llc_sk(sk);
      struct llc_conn_state_trans *trans;

      if (llc->state > NBR_CONN_STATES)
            goto out;
      rc = 0;
      trans = llc_qualify_conn_ev(sk, skb);
      if (trans) {
            rc = llc_exec_conn_trans_actions(sk, trans, skb);
            if (!rc && trans->next_state != NO_STATE_CHANGE) {
                  llc->state = trans->next_state;
                  if (!llc_data_accept_state(llc->state))
                        sk->sk_state_change(sk);
            }
      }
out:
      return rc;
}

/**
 *    llc_qualify_conn_ev - finds transition for event
 *    @sk: connection
 *    @skb: happened event
 *
 *    This function finds transition that matches with happened event.
 *    Returns pointer to found transition on success, %NULL otherwise.
 */
static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
                                          struct sk_buff *skb)
{
      struct llc_conn_state_trans **next_trans;
      llc_conn_ev_qfyr_t *next_qualifier;
      struct llc_conn_state_ev *ev = llc_conn_ev(skb);
      struct llc_sock *llc = llc_sk(sk);
      struct llc_conn_state *curr_state =
                              &llc_conn_state_table[llc->state - 1];

      /* search thru events for this state until
       * list exhausted or until no more
       */
      for (next_trans = curr_state->transitions +
            llc_find_offset(llc->state - 1, ev->type);
           (*next_trans)->ev; next_trans++) {
            if (!((*next_trans)->ev)(sk, skb)) {
                  /* got POSSIBLE event match; the event may require
                   * qualification based on the values of a number of
                   * state flags; if all qualifications are met (i.e.,
                   * if all qualifying functions return success, or 0,
                   * then this is THE event we're looking for
                   */
                  for (next_qualifier = (*next_trans)->ev_qualifiers;
                       next_qualifier && *next_qualifier &&
                       !(*next_qualifier)(sk, skb); next_qualifier++)
                        /* nothing */;
                  if (!next_qualifier || !*next_qualifier)
                        /* all qualifiers executed successfully; this is
                         * our transition; return it so we can perform
                         * the associated actions & change the state
                         */
                        return *next_trans;
            }
      }
      return NULL;
}

/**
 *    llc_exec_conn_trans_actions - executes related actions
 *    @sk: connection
 *    @trans: transition that it's actions must be performed
 *    @skb: event
 *
 *    Executes actions that is related to happened event. Returns 0 for
 *    success, 1 to indicate failure of at least one action.
 */
static int llc_exec_conn_trans_actions(struct sock *sk,
                               struct llc_conn_state_trans *trans,
                               struct sk_buff *skb)
{
      int rc = 0;
      llc_conn_action_t *next_action;

      for (next_action = trans->ev_actions;
           next_action && *next_action; next_action++) {
            int rc2 = (*next_action)(sk, skb);

            if (rc2 == 2) {
                  rc = rc2;
                  break;
            } else if (rc2)
                  rc = 1;
      }
      return rc;
}

/**
 *    __llc_lookup_established - Finds connection for the remote/local sap/mac
 *    @sap: SAP
 *    @daddr: address of remote LLC (MAC + SAP)
 *    @laddr: address of local LLC (MAC + SAP)
 *
 *    Search connection list of the SAP and finds connection using the remote
 *    mac, remote sap, local mac, and local sap. Returns pointer for
 *    connection found, %NULL otherwise.
 *    Caller has to make sure local_bh is disabled.
 */
static struct sock *__llc_lookup_established(struct llc_sap *sap,
                                   struct llc_addr *daddr,
                                   struct llc_addr *laddr)
{
      struct sock *rc;
      struct hlist_node *node;

      read_lock(&sap->sk_list.lock);
      sk_for_each(rc, node, &sap->sk_list.list) {
            struct llc_sock *llc = llc_sk(rc);

            if (llc->laddr.lsap == laddr->lsap &&
                llc->daddr.lsap == daddr->lsap &&
                llc_mac_match(llc->laddr.mac, laddr->mac) &&
                llc_mac_match(llc->daddr.mac, daddr->mac)) {
                  sock_hold(rc);
                  goto found;
            }
      }
      rc = NULL;
found:
      read_unlock(&sap->sk_list.lock);
      return rc;
}

struct sock *llc_lookup_established(struct llc_sap *sap,
                            struct llc_addr *daddr,
                            struct llc_addr *laddr)
{
      struct sock *sk;

      local_bh_disable();
      sk = __llc_lookup_established(sap, daddr, laddr);
      local_bh_enable();
      return sk;
}

/**
 *    llc_lookup_listener - Finds listener for local MAC + SAP
 *    @sap: SAP
 *    @laddr: address of local LLC (MAC + SAP)
 *
 *    Search connection list of the SAP and finds connection listening on
 *    local mac, and local sap. Returns pointer for parent socket found,
 *    %NULL otherwise.
 *    Caller has to make sure local_bh is disabled.
 */
static struct sock *llc_lookup_listener(struct llc_sap *sap,
                              struct llc_addr *laddr)
{
      struct sock *rc;
      struct hlist_node *node;

      read_lock(&sap->sk_list.lock);
      sk_for_each(rc, node, &sap->sk_list.list) {
            struct llc_sock *llc = llc_sk(rc);

            if (rc->sk_type == SOCK_STREAM && rc->sk_state == TCP_LISTEN &&
                llc->laddr.lsap == laddr->lsap &&
                (llc_mac_match(llc->laddr.mac, laddr->mac) ||
                 llc_mac_null(llc->laddr.mac))) {
                  sock_hold(rc);
                  goto found;
            }
      }
      rc = NULL;
found:
      read_unlock(&sap->sk_list.lock);
      return rc;
}

static struct sock *__llc_lookup(struct llc_sap *sap,
                         struct llc_addr *daddr,
                         struct llc_addr *laddr)
{
      struct sock *sk = __llc_lookup_established(sap, daddr, laddr);

      return sk ? : llc_lookup_listener(sap, laddr);
}

/**
 *    llc_data_accept_state - designates if in this state data can be sent.
 *    @state: state of connection.
 *
 *    Returns 0 if data can be sent, 1 otherwise.
 */
u8 llc_data_accept_state(u8 state)
{
      return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
             state != LLC_CONN_STATE_REJ;
}

/**
 *    llc_find_next_offset - finds offset for next category of transitions
 *    @state: state table.
 *    @offset: start offset.
 *
 *    Finds offset of next category of transitions in transition table.
 *    Returns the start index of next category.
 */
static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
{
      u16 cnt = 0;
      struct llc_conn_state_trans **next_trans;

      for (next_trans = state->transitions + offset;
           (*next_trans)->ev; next_trans++)
            ++cnt;
      return cnt;
}

/**
 *    llc_build_offset_table - builds offset table of connection
 *
 *    Fills offset table of connection state transition table
 *    (llc_offset_table).
 */
void __init llc_build_offset_table(void)
{
      struct llc_conn_state *curr_state;
      int state, ev_type, next_offset;

      for (state = 0; state < NBR_CONN_STATES; state++) {
            curr_state = &llc_conn_state_table[state];
            next_offset = 0;
            for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
                  llc_offset_table[state][ev_type] = next_offset;
                  next_offset += llc_find_next_offset(curr_state,
                                              next_offset) + 1;
            }
      }
}

/**
 *    llc_find_offset - finds start offset of category of transitions
 *    @state: state of connection
 *    @ev_type: type of happened event
 *
 *    Finds start offset of desired category of transitions. Returns the
 *    desired start offset.
 */
static int llc_find_offset(int state, int ev_type)
{
      int rc = 0;
      /* at this stage, llc_offset_table[..][2] is not important. it is for
       * init_pf_cycle and I don't know what is it.
       */
      switch (ev_type) {
      case LLC_CONN_EV_TYPE_PRIM:
            rc = llc_offset_table[state][0]; break;
      case LLC_CONN_EV_TYPE_PDU:
            rc = llc_offset_table[state][4]; break;
      case LLC_CONN_EV_TYPE_SIMPLE:
            rc = llc_offset_table[state][1]; break;
      case LLC_CONN_EV_TYPE_P_TMR:
      case LLC_CONN_EV_TYPE_ACK_TMR:
      case LLC_CONN_EV_TYPE_REJ_TMR:
      case LLC_CONN_EV_TYPE_BUSY_TMR:
            rc = llc_offset_table[state][3]; break;
      }
      return rc;
}

/**
 *    llc_sap_add_socket - adds a socket to a SAP
 *    @sap: SAP
 *    @sk: socket
 *
 *    This function adds a socket to sk_list of a SAP.
 */
void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
{
      llc_sap_hold(sap);
      write_lock_bh(&sap->sk_list.lock);
      llc_sk(sk)->sap = sap;
      sk_add_node(sk, &sap->sk_list.list);
      write_unlock_bh(&sap->sk_list.lock);
}

/**
 *    llc_sap_remove_socket - removes a socket from SAP
 *    @sap: SAP
 *    @sk: socket
 *
 *    This function removes a connection from sk_list.list of a SAP if
 *    the connection was in this list.
 */
void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
{
      write_lock_bh(&sap->sk_list.lock);
      sk_del_node_init(sk);
      write_unlock_bh(&sap->sk_list.lock);
      llc_sap_put(sap);
}

/**
 *    llc_conn_rcv - sends received pdus to the connection state machine
 *    @sk: current connection structure.
 *    @skb: received frame.
 *
 *    Sends received pdus to the connection state machine.
 */
static int llc_conn_rcv(struct sock* sk, struct sk_buff *skb)
{
      struct llc_conn_state_ev *ev = llc_conn_ev(skb);

      ev->type   = LLC_CONN_EV_TYPE_PDU;
      ev->reason = 0;
      return llc_conn_state_process(sk, skb);
}

static struct sock *llc_create_incoming_sock(struct sock *sk,
                                   struct net_device *dev,
                                   struct llc_addr *saddr,
                                   struct llc_addr *daddr)
{
      struct sock *newsk = llc_sk_alloc(sk->sk_net, sk->sk_family, GFP_ATOMIC,
                                sk->sk_prot);
      struct llc_sock *newllc, *llc = llc_sk(sk);

      if (!newsk)
            goto out;
      newllc = llc_sk(newsk);
      memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
      memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
      newllc->dev = dev;
      dev_hold(dev);
      llc_sap_add_socket(llc->sap, newsk);
      llc_sap_hold(llc->sap);
out:
      return newsk;
}

void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
{
      struct llc_addr saddr, daddr;
      struct sock *sk;

      llc_pdu_decode_sa(skb, saddr.mac);
      llc_pdu_decode_ssap(skb, &saddr.lsap);
      llc_pdu_decode_da(skb, daddr.mac);
      llc_pdu_decode_dsap(skb, &daddr.lsap);

      sk = __llc_lookup(sap, &saddr, &daddr);
      if (!sk)
            goto drop;

      bh_lock_sock(sk);
      /*
       * This has to be done here and not at the upper layer ->accept
       * method because of the way the PROCOM state machine works:
       * it needs to set several state variables (see, for instance,
       * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
       * the originator of the new connection, and this state has to be
       * in the newly created struct sock private area. -acme
       */
      if (unlikely(sk->sk_state == TCP_LISTEN)) {
            struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
                                                &saddr, &daddr);
            if (!newsk)
                  goto drop_unlock;
            skb_set_owner_r(skb, newsk);
      } else {
            /*
             * Can't be skb_set_owner_r, this will be done at the
             * llc_conn_state_process function, later on, when we will use
             * skb_queue_rcv_skb to send it to upper layers, this is
             * another trick required to cope with how the PROCOM state
             * machine works. -acme
             */
            skb->sk = sk;
      }
      if (!sock_owned_by_user(sk))
            llc_conn_rcv(sk, skb);
      else {
            dprintk("%s: adding to backlog...\n", __FUNCTION__);
            llc_set_backlog_type(skb, LLC_PACKET);
            sk_add_backlog(sk, skb);
      }
out:
      bh_unlock_sock(sk);
      sock_put(sk);
      return;
drop:
      kfree_skb(skb);
      return;
drop_unlock:
      kfree_skb(skb);
      goto out;
}

#undef LLC_REFCNT_DEBUG
#ifdef LLC_REFCNT_DEBUG
static atomic_t llc_sock_nr;
#endif

/**
 *    llc_backlog_rcv - Processes rx frames and expired timers.
 *    @sk: LLC sock (p8022 connection)
 *    @skb: queued rx frame or event
 *
 *    This function processes frames that has received and timers that has
 *    expired during sending an I pdu (refer to data_req_handler).  frames
 *    queue by llc_rcv function (llc_mac.c) and timers queue by timer
 *    callback functions(llc_c_ac.c).
 */
static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
      int rc = 0;
      struct llc_sock *llc = llc_sk(sk);

      if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
            if (likely(llc->state > 1)) /* not closed */
                  rc = llc_conn_rcv(sk, skb);
            else
                  goto out_kfree_skb;
      } else if (llc_backlog_type(skb) == LLC_EVENT) {
            /* timer expiration event */
            if (likely(llc->state > 1))  /* not closed */
                  rc = llc_conn_state_process(sk, skb);
            else
                  goto out_kfree_skb;
      } else {
            printk(KERN_ERR "%s: invalid skb in backlog\n", __FUNCTION__);
            goto out_kfree_skb;
      }
out:
      return rc;
out_kfree_skb:
      kfree_skb(skb);
      goto out;
}

/**
 *     llc_sk_init - Initializes a socket with default llc values.
 *     @sk: socket to initialize.
 *
 *     Initializes a socket with default llc values.
 */
static void llc_sk_init(struct sock* sk)
{
      struct llc_sock *llc = llc_sk(sk);

      llc->state    = LLC_CONN_STATE_ADM;
      llc->inc_cntr = llc->dec_cntr = 2;
      llc->dec_step = llc->connect_step = 1;

      init_timer(&llc->ack_timer.timer);
      llc->ack_timer.expire         = sysctl_llc2_ack_timeout;
      llc->ack_timer.timer.data     = (unsigned long)sk;
      llc->ack_timer.timer.function = llc_conn_ack_tmr_cb;

      init_timer(&llc->pf_cycle_timer.timer);
      llc->pf_cycle_timer.expire       = sysctl_llc2_p_timeout;
      llc->pf_cycle_timer.timer.data     = (unsigned long)sk;
      llc->pf_cycle_timer.timer.function = llc_conn_pf_cycle_tmr_cb;

      init_timer(&llc->rej_sent_timer.timer);
      llc->rej_sent_timer.expire       = sysctl_llc2_rej_timeout;
      llc->rej_sent_timer.timer.data     = (unsigned long)sk;
      llc->rej_sent_timer.timer.function = llc_conn_rej_tmr_cb;

      init_timer(&llc->busy_state_timer.timer);
      llc->busy_state_timer.expire       = sysctl_llc2_busy_timeout;
      llc->busy_state_timer.timer.data     = (unsigned long)sk;
      llc->busy_state_timer.timer.function = llc_conn_busy_tmr_cb;

      llc->n2 = 2;   /* max retransmit */
      llc->k  = 2;   /* tx win size, will adjust dynam */
      llc->rw = 128; /* rx win size (opt and equal to
                  * tx_win of remote LLC) */
      skb_queue_head_init(&llc->pdu_unack_q);
      sk->sk_backlog_rcv = llc_backlog_rcv;
}

/**
 *    llc_sk_alloc - Allocates LLC sock
 *    @family: upper layer protocol family
 *    @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
 *
 *    Allocates a LLC sock and initializes it. Returns the new LLC sock
 *    or %NULL if there's no memory available for one
 */
struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot)
{
      struct sock *sk = sk_alloc(net, family, priority, prot);

      if (!sk)
            goto out;
      llc_sk_init(sk);
      sock_init_data(NULL, sk);
#ifdef LLC_REFCNT_DEBUG
      atomic_inc(&llc_sock_nr);
      printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
            __FUNCTION__, atomic_read(&llc_sock_nr));
#endif
out:
      return sk;
}

/**
 *    llc_sk_free - Frees a LLC socket
 *    @sk - socket to free
 *
 *    Frees a LLC socket
 */
void llc_sk_free(struct sock *sk)
{
      struct llc_sock *llc = llc_sk(sk);

      llc->state = LLC_CONN_OUT_OF_SVC;
      /* Stop all (possibly) running timers */
      llc_conn_ac_stop_all_timers(sk, NULL);
#ifdef DEBUG_LLC_CONN_ALLOC
      printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __FUNCTION__,
            skb_queue_len(&llc->pdu_unack_q),
            skb_queue_len(&sk->sk_write_queue));
#endif
      skb_queue_purge(&sk->sk_receive_queue);
      skb_queue_purge(&sk->sk_write_queue);
      skb_queue_purge(&llc->pdu_unack_q);
#ifdef LLC_REFCNT_DEBUG
      if (atomic_read(&sk->sk_refcnt) != 1) {
            printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
                  sk, __FUNCTION__, atomic_read(&sk->sk_refcnt));
            printk(KERN_DEBUG "%d LLC sockets are still alive\n",
                  atomic_read(&llc_sock_nr));
      } else {
            atomic_dec(&llc_sock_nr);
            printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
                  __FUNCTION__, atomic_read(&llc_sock_nr));
      }
#endif
      sock_put(sk);
}

/**
 *    llc_sk_reset - resets a connection
 *    @sk: LLC socket to reset
 *
 *    Resets a connection to the out of service state. Stops its timers
 *    and frees any frames in the queues of the connection.
 */
void llc_sk_reset(struct sock *sk)
{
      struct llc_sock *llc = llc_sk(sk);

      llc_conn_ac_stop_all_timers(sk, NULL);
      skb_queue_purge(&sk->sk_write_queue);
      skb_queue_purge(&llc->pdu_unack_q);
      llc->remote_busy_flag   = 0;
      llc->cause_flag         = 0;
      llc->retry_count  = 0;
      llc_conn_set_p_flag(sk, 0);
      llc->f_flag       = 0;
      llc->s_flag       = 0;
      llc->ack_pf       = 0;
      llc->first_pdu_Ns = 0;
      llc->ack_must_be_send   = 0;
      llc->dec_step           = 1;
      llc->inc_cntr           = 2;
      llc->dec_cntr           = 2;
      llc->X                  = 0;
      llc->failed_data_req    = 0 ;
      llc->last_nr            = 0;
}

Generated by  Doxygen 1.6.0   Back to index