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

af_llc.c

/*
 * af_llc.c - LLC User Interface SAPs
 * Description:
 *   Functions in this module are implementation of socket based llc
 *   communications for the Linux operating system. Support of llc class
 *   one and class two is provided via SOCK_DGRAM and SOCK_STREAM
 *   respectively.
 *
 *   An llc2 connection is (mac + sap), only one llc2 sap connection
 *   is allowed per mac. Though one sap may have multiple mac + sap
 *   connections.
 *
 * Copyright (c) 2001 by Jay Schulist <jschlst@samba.org>
 *           2002-2003 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/compiler.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
#include <net/llc.h>
#include <net/llc_sap.h>
#include <net/llc_pdu.h>
#include <net/llc_conn.h>
#include <net/tcp_states.h>

/* remember: uninitialized global data is zeroed because its in .bss */
static u16 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
static u16 llc_ui_sap_link_no_max[256];
static struct sockaddr_llc llc_ui_addrnull;
static const struct proto_ops llc_ui_ops;

static int llc_ui_wait_for_conn(struct sock *sk, long timeout);
static int llc_ui_wait_for_disc(struct sock *sk, long timeout);
static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout);

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

/**
 *    llc_ui_next_link_no - return the next unused link number for a sap
 *    @sap: Address of sap to get link number from.
 *
 *    Return the next unused link number for a given sap.
 */
static inline u16 llc_ui_next_link_no(int sap)
{
      return llc_ui_sap_link_no_max[sap]++;
}

/**
 *    llc_proto_type - return eth protocol for ARP header type
 *    @arphrd: ARP header type.
 *
 *    Given an ARP header type return the corresponding ethernet protocol.
 */
static inline __be16 llc_proto_type(u16 arphrd)
{
      return arphrd == ARPHRD_IEEE802_TR ?
                   htons(ETH_P_TR_802_2) : htons(ETH_P_802_2);
}

/**
 *    llc_ui_addr_null - determines if a address structure is null
 *    @addr: Address to test if null.
 */
static inline u8 llc_ui_addr_null(struct sockaddr_llc *addr)
{
      return !memcmp(addr, &llc_ui_addrnull, sizeof(*addr));
}

/**
 *    llc_ui_header_len - return length of llc header based on operation
 *    @sk: Socket which contains a valid llc socket type.
 *    @addr: Complete sockaddr_llc structure received from the user.
 *
 *    Provide the length of the llc header depending on what kind of
 *    operation the user would like to perform and the type of socket.
 *    Returns the correct llc header length.
 */
static inline u8 llc_ui_header_len(struct sock *sk, struct sockaddr_llc *addr)
{
      u8 rc = LLC_PDU_LEN_U;

      if (addr->sllc_test || addr->sllc_xid)
            rc = LLC_PDU_LEN_U;
      else if (sk->sk_type == SOCK_STREAM)
            rc = LLC_PDU_LEN_I;
      return rc;
}

/**
 *    llc_ui_send_data - send data via reliable llc2 connection
 *    @sk: Connection the socket is using.
 *    @skb: Data the user wishes to send.
 *    @addr: Source and destination fields provided by the user.
 *    @noblock: can we block waiting for data?
 *
 *    Send data via reliable llc2 connection.
 *    Returns 0 upon success, non-zero if action did not succeed.
 */
static int llc_ui_send_data(struct sock* sk, struct sk_buff *skb, int noblock)
{
      struct llc_sock* llc = llc_sk(sk);
      int rc = 0;

      if (unlikely(llc_data_accept_state(llc->state) ||
                 llc->remote_busy_flag ||
                 llc->p_flag)) {
            long timeout = sock_sndtimeo(sk, noblock);

            rc = llc_ui_wait_for_busy_core(sk, timeout);
      }
      if (unlikely(!rc))
            rc = llc_build_and_send_pkt(sk, skb);
      return rc;
}

static void llc_ui_sk_init(struct socket *sock, struct sock *sk)
{
      sk->sk_type = sock->type;
      sk->sk_sleep      = &sock->wait;
      sk->sk_socket     = sock;
      sock->sk    = sk;
      sock->ops   = &llc_ui_ops;
}

static struct proto llc_proto = {
      .name   = "LLC",
      .owner        = THIS_MODULE,
      .obj_size = sizeof(struct llc_sock),
};

/**
 *    llc_ui_create - alloc and init a new llc_ui socket
 *    @sock: Socket to initialize and attach allocated sk to.
 *    @protocol: Unused.
 *
 *    Allocate and initialize a new llc_ui socket, validate the user wants a
 *    socket type we have available.
 *    Returns 0 upon success, negative upon failure.
 */
static int llc_ui_create(struct net *net, struct socket *sock, int protocol)
{
      struct sock *sk;
      int rc = -ESOCKTNOSUPPORT;

      if (net != &init_net)
            return -EAFNOSUPPORT;

      if (likely(sock->type == SOCK_DGRAM || sock->type == SOCK_STREAM)) {
            rc = -ENOMEM;
            sk = llc_sk_alloc(net, PF_LLC, GFP_KERNEL, &llc_proto);
            if (sk) {
                  rc = 0;
                  llc_ui_sk_init(sock, sk);
            }
      }
      return rc;
}

/**
 *    llc_ui_release - shutdown socket
 *    @sock: Socket to release.
 *
 *    Shutdown and deallocate an existing socket.
 */
static int llc_ui_release(struct socket *sock)
{
      struct sock *sk = sock->sk;
      struct llc_sock *llc;

      if (unlikely(sk == NULL))
            goto out;
      sock_hold(sk);
      lock_sock(sk);
      llc = llc_sk(sk);
      dprintk("%s: closing local(%02X) remote(%02X)\n", __FUNCTION__,
            llc->laddr.lsap, llc->daddr.lsap);
      if (!llc_send_disc(sk))
            llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
      if (!sock_flag(sk, SOCK_ZAPPED)) {
            llc_sap_put(llc->sap);
            llc_sap_remove_socket(llc->sap, sk);
      }
      release_sock(sk);
      if (llc->dev)
            dev_put(llc->dev);
      sock_put(sk);
      llc_sk_free(sk);
out:
      return 0;
}

/**
 *    llc_ui_autoport - provide dynamically allocate SAP number
 *
 *    Provide the caller with a dynamically allocated SAP number according
 *    to the rules that are set in this function. Returns: 0, upon failure,
 *    SAP number otherwise.
 */
static int llc_ui_autoport(void)
{
      struct llc_sap *sap;
      int i, tries = 0;

      while (tries < LLC_SAP_DYN_TRIES) {
            for (i = llc_ui_sap_last_autoport;
                 i < LLC_SAP_DYN_STOP; i += 2) {
                  sap = llc_sap_find(i);
                  if (!sap) {
                        llc_ui_sap_last_autoport = i + 2;
                        goto out;
                  }
                  llc_sap_put(sap);
            }
            llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
            tries++;
      }
      i = 0;
out:
      return i;
}

/**
 *    llc_ui_autobind - automatically bind a socket to a sap
 *    @sock: socket to bind
 *    @addr: address to connect to
 *
 *    Used by llc_ui_connect and llc_ui_sendmsg when the user hasn't
 *    specifically used llc_ui_bind to bind to an specific address/sap
 *
 *    Returns: 0 upon success, negative otherwise.
 */
static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
{
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      struct llc_sap *sap;
      int rc = -EINVAL;

      if (!sock_flag(sk, SOCK_ZAPPED))
            goto out;
      rc = -ENODEV;
      llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
      if (!llc->dev)
            goto out;
      rc = -EUSERS;
      llc->laddr.lsap = llc_ui_autoport();
      if (!llc->laddr.lsap)
            goto out;
      rc = -EBUSY; /* some other network layer is using the sap */
      sap = llc_sap_open(llc->laddr.lsap, NULL);
      if (!sap)
            goto out;
      memcpy(llc->laddr.mac, llc->dev->dev_addr, IFHWADDRLEN);
      memcpy(&llc->addr, addr, sizeof(llc->addr));
      /* assign new connection to its SAP */
      llc_sap_add_socket(sap, sk);
      sock_reset_flag(sk, SOCK_ZAPPED);
      rc = 0;
out:
      return rc;
}

/**
 *    llc_ui_bind - bind a socket to a specific address.
 *    @sock: Socket to bind an address to.
 *    @uaddr: Address the user wants the socket bound to.
 *    @addrlen: Length of the uaddr structure.
 *
 *    Bind a socket to a specific address. For llc a user is able to bind to
 *    a specific sap only or mac + sap.
 *    If the user desires to bind to a specific mac + sap, it is possible to
 *    have multiple sap connections via multiple macs.
 *    Bind and autobind for that matter must enforce the correct sap usage
 *    otherwise all hell will break loose.
 *    Returns: 0 upon success, negative otherwise.
 */
static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
{
      struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      struct llc_sap *sap;
      int rc = -EINVAL;

      dprintk("%s: binding %02X\n", __FUNCTION__, addr->sllc_sap);
      if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
            goto out;
      rc = -EAFNOSUPPORT;
      if (unlikely(addr->sllc_family != AF_LLC))
            goto out;
      rc = -ENODEV;
      rtnl_lock();
      llc->dev = dev_getbyhwaddr(&init_net, addr->sllc_arphrd, addr->sllc_mac);
      rtnl_unlock();
      if (!llc->dev)
            goto out;
      if (!addr->sllc_sap) {
            rc = -EUSERS;
            addr->sllc_sap = llc_ui_autoport();
            if (!addr->sllc_sap)
                  goto out;
      }
      sap = llc_sap_find(addr->sllc_sap);
      if (!sap) {
            sap = llc_sap_open(addr->sllc_sap, NULL);
            rc = -EBUSY; /* some other network layer is using the sap */
            if (!sap)
                  goto out;
            llc_sap_hold(sap);
      } else {
            struct llc_addr laddr, daddr;
            struct sock *ask;

            memset(&laddr, 0, sizeof(laddr));
            memset(&daddr, 0, sizeof(daddr));
            /*
             * FIXME: check if the address is multicast,
             *      only SOCK_DGRAM can do this.
             */
            memcpy(laddr.mac, addr->sllc_mac, IFHWADDRLEN);
            laddr.lsap = addr->sllc_sap;
            rc = -EADDRINUSE; /* mac + sap clash. */
            ask = llc_lookup_established(sap, &daddr, &laddr);
            if (ask) {
                  sock_put(ask);
                  goto out_put;
            }
      }
      llc->laddr.lsap = addr->sllc_sap;
      memcpy(llc->laddr.mac, addr->sllc_mac, IFHWADDRLEN);
      memcpy(&llc->addr, addr, sizeof(llc->addr));
      /* assign new connection to its SAP */
      llc_sap_add_socket(sap, sk);
      sock_reset_flag(sk, SOCK_ZAPPED);
      rc = 0;
out_put:
      llc_sap_put(sap);
out:
      return rc;
}

/**
 *    llc_ui_shutdown - shutdown a connect llc2 socket.
 *    @sock: Socket to shutdown.
 *    @how: What part of the socket to shutdown.
 *
 *    Shutdown a connected llc2 socket. Currently this function only supports
 *    shutting down both sends and receives (2), we could probably make this
 *    function such that a user can shutdown only half the connection but not
 *    right now.
 *    Returns: 0 upon success, negative otherwise.
 */
static int llc_ui_shutdown(struct socket *sock, int how)
{
      struct sock *sk = sock->sk;
      int rc = -ENOTCONN;

      lock_sock(sk);
      if (unlikely(sk->sk_state != TCP_ESTABLISHED))
            goto out;
      rc = -EINVAL;
      if (how != 2)
            goto out;
      rc = llc_send_disc(sk);
      if (!rc)
            rc = llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
      /* Wake up anyone sleeping in poll */
      sk->sk_state_change(sk);
out:
      release_sock(sk);
      return rc;
}

/**
 *    llc_ui_connect - Connect to a remote llc2 mac + sap.
 *    @sock: Socket which will be connected to the remote destination.
 *    @uaddr: Remote and possibly the local address of the new connection.
 *    @addrlen: Size of uaddr structure.
 *    @flags: Operational flags specified by the user.
 *
 *    Connect to a remote llc2 mac + sap. The caller must specify the
 *    destination mac and address to connect to. If the user hasn't previously
 *    called bind(2) with a smac the address of the first interface of the
 *    specified arp type will be used.
 *    This function will autobind if user did not previously call bind.
 *    Returns: 0 upon success, negative otherwise.
 */
static int llc_ui_connect(struct socket *sock, struct sockaddr *uaddr,
                    int addrlen, int flags)
{
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
      int rc = -EINVAL;

      lock_sock(sk);
      if (unlikely(addrlen != sizeof(*addr)))
            goto out;
      rc = -EAFNOSUPPORT;
      if (unlikely(addr->sllc_family != AF_LLC))
            goto out;
      if (unlikely(sk->sk_type != SOCK_STREAM))
            goto out;
      rc = -EALREADY;
      if (unlikely(sock->state == SS_CONNECTING))
            goto out;
      /* bind connection to sap if user hasn't done it. */
      if (sock_flag(sk, SOCK_ZAPPED)) {
            /* bind to sap with null dev, exclusive */
            rc = llc_ui_autobind(sock, addr);
            if (rc)
                  goto out;
      }
      llc->daddr.lsap = addr->sllc_sap;
      memcpy(llc->daddr.mac, addr->sllc_mac, IFHWADDRLEN);
      sock->state = SS_CONNECTING;
      sk->sk_state   = TCP_SYN_SENT;
      llc->link   = llc_ui_next_link_no(llc->sap->laddr.lsap);
      rc = llc_establish_connection(sk, llc->dev->dev_addr,
                              addr->sllc_mac, addr->sllc_sap);
      if (rc) {
            dprintk("%s: llc_ui_send_conn failed :-(\n", __FUNCTION__);
            sock->state  = SS_UNCONNECTED;
            sk->sk_state = TCP_CLOSE;
            goto out;
      }

      if (sk->sk_state == TCP_SYN_SENT) {
            const long timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);

            if (!timeo || !llc_ui_wait_for_conn(sk, timeo))
                  goto out;

            rc = sock_intr_errno(timeo);
            if (signal_pending(current))
                  goto out;
      }

      if (sk->sk_state == TCP_CLOSE)
            goto sock_error;

      sock->state = SS_CONNECTED;
      rc = 0;
out:
      release_sock(sk);
      return rc;
sock_error:
      rc = sock_error(sk) ? : -ECONNABORTED;
      sock->state = SS_UNCONNECTED;
      goto out;
}

/**
 *    llc_ui_listen - allow a normal socket to accept incoming connections
 *    @sock: Socket to allow incoming connections on.
 *    @backlog: Number of connections to queue.
 *
 *    Allow a normal socket to accept incoming connections.
 *    Returns 0 upon success, negative otherwise.
 */
static int llc_ui_listen(struct socket *sock, int backlog)
{
      struct sock *sk = sock->sk;
      int rc = -EINVAL;

      lock_sock(sk);
      if (unlikely(sock->state != SS_UNCONNECTED))
            goto out;
      rc = -EOPNOTSUPP;
      if (unlikely(sk->sk_type != SOCK_STREAM))
            goto out;
      rc = -EAGAIN;
      if (sock_flag(sk, SOCK_ZAPPED))
            goto out;
      rc = 0;
      if (!(unsigned)backlog) /* BSDism */
            backlog = 1;
      sk->sk_max_ack_backlog = backlog;
      if (sk->sk_state != TCP_LISTEN) {
            sk->sk_ack_backlog = 0;
            sk->sk_state         = TCP_LISTEN;
      }
      sk->sk_socket->flags |= __SO_ACCEPTCON;
out:
      release_sock(sk);
      return rc;
}

static int llc_ui_wait_for_disc(struct sock *sk, long timeout)
{
      DEFINE_WAIT(wait);
      int rc = 0;

      while (1) {
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
            if (sk_wait_event(sk, &timeout, sk->sk_state == TCP_CLOSE))
                  break;
            rc = -ERESTARTSYS;
            if (signal_pending(current))
                  break;
            rc = -EAGAIN;
            if (!timeout)
                  break;
            rc = 0;
      }
      finish_wait(sk->sk_sleep, &wait);
      return rc;
}

static int llc_ui_wait_for_conn(struct sock *sk, long timeout)
{
      DEFINE_WAIT(wait);

      while (1) {
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
            if (sk_wait_event(sk, &timeout, sk->sk_state != TCP_SYN_SENT))
                  break;
            if (signal_pending(current) || !timeout)
                  break;
      }
      finish_wait(sk->sk_sleep, &wait);
      return timeout;
}

static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout)
{
      DEFINE_WAIT(wait);
      struct llc_sock *llc = llc_sk(sk);
      int rc;

      while (1) {
            prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
            rc = 0;
            if (sk_wait_event(sk, &timeout,
                          (sk->sk_shutdown & RCV_SHUTDOWN) ||
                          (!llc_data_accept_state(llc->state) &&
                           !llc->remote_busy_flag &&
                           !llc->p_flag)))
                  break;
            rc = -ERESTARTSYS;
            if (signal_pending(current))
                  break;
            rc = -EAGAIN;
            if (!timeout)
                  break;
      }
      finish_wait(sk->sk_sleep, &wait);
      return rc;
}

static int llc_wait_data(struct sock *sk, long timeo)
{
      int rc;

      while (1) {
            /*
             * POSIX 1003.1g mandates this order.
             */
            rc = sock_error(sk);
            if (rc)
                  break;
            rc = 0;
            if (sk->sk_shutdown & RCV_SHUTDOWN)
                  break;
            rc = -EAGAIN;
            if (!timeo)
                  break;
            rc = sock_intr_errno(timeo);
            if (signal_pending(current))
                  break;
            rc = 0;
            if (sk_wait_data(sk, &timeo))
                  break;
      }
      return rc;
}

/**
 *    llc_ui_accept - accept a new incoming connection.
 *    @sock: Socket which connections arrive on.
 *    @newsock: Socket to move incoming connection to.
 *    @flags: User specified operational flags.
 *
 *    Accept a new incoming connection.
 *    Returns 0 upon success, negative otherwise.
 */
static int llc_ui_accept(struct socket *sock, struct socket *newsock, int flags)
{
      struct sock *sk = sock->sk, *newsk;
      struct llc_sock *llc, *newllc;
      struct sk_buff *skb;
      int rc = -EOPNOTSUPP;

      dprintk("%s: accepting on %02X\n", __FUNCTION__,
            llc_sk(sk)->laddr.lsap);
      lock_sock(sk);
      if (unlikely(sk->sk_type != SOCK_STREAM))
            goto out;
      rc = -EINVAL;
      if (unlikely(sock->state != SS_UNCONNECTED ||
                 sk->sk_state != TCP_LISTEN))
            goto out;
      /* wait for a connection to arrive. */
      if (skb_queue_empty(&sk->sk_receive_queue)) {
            rc = llc_wait_data(sk, sk->sk_rcvtimeo);
            if (rc)
                  goto out;
      }
      dprintk("%s: got a new connection on %02X\n", __FUNCTION__,
            llc_sk(sk)->laddr.lsap);
      skb = skb_dequeue(&sk->sk_receive_queue);
      rc = -EINVAL;
      if (!skb->sk)
            goto frees;
      rc = 0;
      newsk = skb->sk;
      /* attach connection to a new socket. */
      llc_ui_sk_init(newsock, newsk);
      sock_reset_flag(newsk, SOCK_ZAPPED);
      newsk->sk_state         = TCP_ESTABLISHED;
      newsock->state          = SS_CONNECTED;
      llc               = llc_sk(sk);
      newllc                  = llc_sk(newsk);
      memcpy(&newllc->addr, &llc->addr, sizeof(newllc->addr));
      newllc->link = llc_ui_next_link_no(newllc->laddr.lsap);

      /* put original socket back into a clean listen state. */
      sk->sk_state = TCP_LISTEN;
      sk->sk_ack_backlog--;
      dprintk("%s: ok success on %02X, client on %02X\n", __FUNCTION__,
            llc_sk(sk)->addr.sllc_sap, newllc->daddr.lsap);
frees:
      kfree_skb(skb);
out:
      release_sock(sk);
      return rc;
}

/**
 *    llc_ui_recvmsg - copy received data to the socket user.
 *    @sock: Socket to copy data from.
 *    @msg: Various user space related information.
 *    @len: Size of user buffer.
 *    @flags: User specified flags.
 *
 *    Copy received data to the socket user.
 *    Returns non-negative upon success, negative otherwise.
 */
static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock,
                    struct msghdr *msg, size_t len, int flags)
{
      struct sockaddr_llc *uaddr = (struct sockaddr_llc *)msg->msg_name;
      const int nonblock = flags & MSG_DONTWAIT;
      struct sk_buff *skb = NULL;
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      size_t copied = 0;
      u32 peek_seq = 0;
      u32 *seq;
      unsigned long used;
      int target; /* Read at least this many bytes */
      long timeo;

      lock_sock(sk);
      copied = -ENOTCONN;
      if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))
            goto out;

      timeo = sock_rcvtimeo(sk, nonblock);

      seq = &llc->copied_seq;
      if (flags & MSG_PEEK) {
            peek_seq = llc->copied_seq;
            seq = &peek_seq;
      }

      target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
      copied = 0;

      do {
            u32 offset;

            /*
             * We need to check signals first, to get correct SIGURG
             * handling. FIXME: Need to check this doesn't impact 1003.1g
             * and move it down to the bottom of the loop
             */
            if (signal_pending(current)) {
                  if (copied)
                        break;
                  copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
                  break;
            }

            /* Next get a buffer. */

            skb = skb_peek(&sk->sk_receive_queue);
            if (skb) {
                  offset = *seq;
                  goto found_ok_skb;
            }
            /* Well, if we have backlog, try to process it now yet. */

            if (copied >= target && !sk->sk_backlog.tail)
                  break;

            if (copied) {
                  if (sk->sk_err ||
                      sk->sk_state == TCP_CLOSE ||
                      (sk->sk_shutdown & RCV_SHUTDOWN) ||
                      !timeo ||
                      (flags & MSG_PEEK))
                        break;
            } else {
                  if (sock_flag(sk, SOCK_DONE))
                        break;

                  if (sk->sk_err) {
                        copied = sock_error(sk);
                        break;
                  }
                  if (sk->sk_shutdown & RCV_SHUTDOWN)
                        break;

                  if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSE) {
                        if (!sock_flag(sk, SOCK_DONE)) {
                              /*
                               * This occurs when user tries to read
                               * from never connected socket.
                               */
                              copied = -ENOTCONN;
                              break;
                        }
                        break;
                  }
                  if (!timeo) {
                        copied = -EAGAIN;
                        break;
                  }
            }

            if (copied >= target) { /* Do not sleep, just process backlog. */
                  release_sock(sk);
                  lock_sock(sk);
            } else
                  sk_wait_data(sk, &timeo);

            if ((flags & MSG_PEEK) && peek_seq != llc->copied_seq) {
                  if (net_ratelimit())
                        printk(KERN_DEBUG "LLC(%s:%d): Application "
                                      "bug, race in MSG_PEEK.\n",
                               current->comm, task_pid_nr(current));
                  peek_seq = llc->copied_seq;
            }
            continue;
      found_ok_skb:
            /* Ok so how much can we use? */
            used = skb->len - offset;
            if (len < used)
                  used = len;

            if (!(flags & MSG_TRUNC)) {
                  int rc = skb_copy_datagram_iovec(skb, offset,
                                           msg->msg_iov, used);
                  if (rc) {
                        /* Exception. Bailout! */
                        if (!copied)
                              copied = -EFAULT;
                        break;
                  }
            }

            *seq += used;
            copied += used;
            len -= used;

            if (!(flags & MSG_PEEK)) {
                  sk_eat_skb(sk, skb, 0);
                  *seq = 0;
            }

            /* For non stream protcols we get one packet per recvmsg call */
            if (sk->sk_type != SOCK_STREAM)
                  goto copy_uaddr;

            /* Partial read */
            if (used + offset < skb->len)
                  continue;
      } while (len > 0);

out:
      release_sock(sk);
      return copied;
copy_uaddr:
      if (uaddr != NULL && skb != NULL) {
            memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
            msg->msg_namelen = sizeof(*uaddr);
      }
      goto out;
}

/**
 *    llc_ui_sendmsg - Transmit data provided by the socket user.
 *    @sock: Socket to transmit data from.
 *    @msg: Various user related information.
 *    @len: Length of data to transmit.
 *
 *    Transmit data provided by the socket user.
 *    Returns non-negative upon success, negative otherwise.
 */
static int llc_ui_sendmsg(struct kiocb *iocb, struct socket *sock,
                    struct msghdr *msg, size_t len)
{
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      struct sockaddr_llc *addr = (struct sockaddr_llc *)msg->msg_name;
      int flags = msg->msg_flags;
      int noblock = flags & MSG_DONTWAIT;
      struct sk_buff *skb;
      size_t size = 0;
      int rc = -EINVAL, copied = 0, hdrlen;

      dprintk("%s: sending from %02X to %02X\n", __FUNCTION__,
            llc->laddr.lsap, llc->daddr.lsap);
      lock_sock(sk);
      if (addr) {
            if (msg->msg_namelen < sizeof(*addr))
                  goto release;
      } else {
            if (llc_ui_addr_null(&llc->addr))
                  goto release;
            addr = &llc->addr;
      }
      /* must bind connection to sap if user hasn't done it. */
      if (sock_flag(sk, SOCK_ZAPPED)) {
            /* bind to sap with null dev, exclusive. */
            rc = llc_ui_autobind(sock, addr);
            if (rc)
                  goto release;
      }
      hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr);
      size = hdrlen + len;
      if (size > llc->dev->mtu)
            size = llc->dev->mtu;
      copied = size - hdrlen;
      release_sock(sk);
      skb = sock_alloc_send_skb(sk, size, noblock, &rc);
      lock_sock(sk);
      if (!skb)
            goto release;
      skb->dev      = llc->dev;
      skb->protocol = llc_proto_type(addr->sllc_arphrd);
      skb_reserve(skb, hdrlen);
      rc = memcpy_fromiovec(skb_put(skb, copied), msg->msg_iov, copied);
      if (rc)
            goto out;
      if (sk->sk_type == SOCK_DGRAM || addr->sllc_ua) {
            llc_build_and_send_ui_pkt(llc->sap, skb, addr->sllc_mac,
                                addr->sllc_sap);
            goto out;
      }
      if (addr->sllc_test) {
            llc_build_and_send_test_pkt(llc->sap, skb, addr->sllc_mac,
                                  addr->sllc_sap);
            goto out;
      }
      if (addr->sllc_xid) {
            llc_build_and_send_xid_pkt(llc->sap, skb, addr->sllc_mac,
                                 addr->sllc_sap);
            goto out;
      }
      rc = -ENOPROTOOPT;
      if (!(sk->sk_type == SOCK_STREAM && !addr->sllc_ua))
            goto out;
      rc = llc_ui_send_data(sk, skb, noblock);
out:
      if (rc) {
            kfree_skb(skb);
release:
            dprintk("%s: failed sending from %02X to %02X: %d\n",
                  __FUNCTION__, llc->laddr.lsap, llc->daddr.lsap, rc);
      }
      release_sock(sk);
      return rc ? : copied;
}

/**
 *    llc_ui_getname - return the address info of a socket
 *    @sock: Socket to get address of.
 *    @uaddr: Address structure to return information.
 *    @uaddrlen: Length of address structure.
 *    @peer: Does user want local or remote address information.
 *
 *    Return the address information of a socket.
 */
static int llc_ui_getname(struct socket *sock, struct sockaddr *uaddr,
                    int *uaddrlen, int peer)
{
      struct sockaddr_llc sllc;
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      int rc = 0;

      lock_sock(sk);
      if (sock_flag(sk, SOCK_ZAPPED))
            goto out;
      *uaddrlen = sizeof(sllc);
      memset(uaddr, 0, *uaddrlen);
      if (peer) {
            rc = -ENOTCONN;
            if (sk->sk_state != TCP_ESTABLISHED)
                  goto out;
            if(llc->dev)
                  sllc.sllc_arphrd = llc->dev->type;
            sllc.sllc_sap = llc->daddr.lsap;
            memcpy(&sllc.sllc_mac, &llc->daddr.mac, IFHWADDRLEN);
      } else {
            rc = -EINVAL;
            if (!llc->sap)
                  goto out;
            sllc.sllc_sap = llc->sap->laddr.lsap;

            if (llc->dev) {
                  sllc.sllc_arphrd = llc->dev->type;
                  memcpy(&sllc.sllc_mac, &llc->dev->dev_addr,
                         IFHWADDRLEN);
            }
      }
      rc = 0;
      sllc.sllc_family = AF_LLC;
      memcpy(uaddr, &sllc, sizeof(sllc));
out:
      release_sock(sk);
      return rc;
}

/**
 *    llc_ui_ioctl - io controls for PF_LLC
 *    @sock: Socket to get/set info
 *    @cmd: command
 *    @arg: optional argument for cmd
 *
 *    get/set info on llc sockets
 */
static int llc_ui_ioctl(struct socket *sock, unsigned int cmd,
                  unsigned long arg)
{
      return -ENOIOCTLCMD;
}

/**
 *    llc_ui_setsockopt - set various connection specific parameters.
 *    @sock: Socket to set options on.
 *    @level: Socket level user is requesting operations on.
 *    @optname: Operation name.
 *    @optval User provided operation data.
 *    @optlen: Length of optval.
 *
 *    Set various connection specific parameters.
 */
static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
                       char __user *optval, int optlen)
{
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      int rc = -EINVAL, opt;

      lock_sock(sk);
      if (unlikely(level != SOL_LLC || optlen != sizeof(int)))
            goto out;
      rc = get_user(opt, (int __user *)optval);
      if (rc)
            goto out;
      rc = -EINVAL;
      switch (optname) {
      case LLC_OPT_RETRY:
            if (opt > LLC_OPT_MAX_RETRY)
                  goto out;
            llc->n2 = opt;
            break;
      case LLC_OPT_SIZE:
            if (opt > LLC_OPT_MAX_SIZE)
                  goto out;
            llc->n1 = opt;
            break;
      case LLC_OPT_ACK_TMR_EXP:
            if (opt > LLC_OPT_MAX_ACK_TMR_EXP)
                  goto out;
            llc->ack_timer.expire = opt * HZ;
            break;
      case LLC_OPT_P_TMR_EXP:
            if (opt > LLC_OPT_MAX_P_TMR_EXP)
                  goto out;
            llc->pf_cycle_timer.expire = opt * HZ;
            break;
      case LLC_OPT_REJ_TMR_EXP:
            if (opt > LLC_OPT_MAX_REJ_TMR_EXP)
                  goto out;
            llc->rej_sent_timer.expire = opt * HZ;
            break;
      case LLC_OPT_BUSY_TMR_EXP:
            if (opt > LLC_OPT_MAX_BUSY_TMR_EXP)
                  goto out;
            llc->busy_state_timer.expire = opt * HZ;
            break;
      case LLC_OPT_TX_WIN:
            if (opt > LLC_OPT_MAX_WIN)
                  goto out;
            llc->k = opt;
            break;
      case LLC_OPT_RX_WIN:
            if (opt > LLC_OPT_MAX_WIN)
                  goto out;
            llc->rw = opt;
            break;
      default:
            rc = -ENOPROTOOPT;
            goto out;
      }
      rc = 0;
out:
      release_sock(sk);
      return rc;
}

/**
 *    llc_ui_getsockopt - get connection specific socket info
 *    @sock: Socket to get information from.
 *    @level: Socket level user is requesting operations on.
 *    @optname: Operation name.
 *    @optval: Variable to return operation data in.
 *    @optlen: Length of optval.
 *
 *    Get connection specific socket information.
 */
static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
                       char __user *optval, int __user *optlen)
{
      struct sock *sk = sock->sk;
      struct llc_sock *llc = llc_sk(sk);
      int val = 0, len = 0, rc = -EINVAL;

      lock_sock(sk);
      if (unlikely(level != SOL_LLC))
            goto out;
      rc = get_user(len, optlen);
      if (rc)
            goto out;
      rc = -EINVAL;
      if (len != sizeof(int))
            goto out;
      switch (optname) {
      case LLC_OPT_RETRY:
            val = llc->n2;                            break;
      case LLC_OPT_SIZE:
            val = llc->n1;                            break;
      case LLC_OPT_ACK_TMR_EXP:
            val = llc->ack_timer.expire / HZ;         break;
      case LLC_OPT_P_TMR_EXP:
            val = llc->pf_cycle_timer.expire / HZ;          break;
      case LLC_OPT_REJ_TMR_EXP:
            val = llc->rej_sent_timer.expire / HZ;          break;
      case LLC_OPT_BUSY_TMR_EXP:
            val = llc->busy_state_timer.expire / HZ;  break;
      case LLC_OPT_TX_WIN:
            val = llc->k;                       break;
      case LLC_OPT_RX_WIN:
            val = llc->rw;                      break;
      default:
            rc = -ENOPROTOOPT;
            goto out;
      }
      rc = 0;
      if (put_user(len, optlen) || copy_to_user(optval, &val, len))
            rc = -EFAULT;
out:
      release_sock(sk);
      return rc;
}

static struct net_proto_family llc_ui_family_ops = {
      .family = PF_LLC,
      .create = llc_ui_create,
      .owner      = THIS_MODULE,
};

static const struct proto_ops llc_ui_ops = {
      .family          = PF_LLC,
      .owner       = THIS_MODULE,
      .release     = llc_ui_release,
      .bind      = llc_ui_bind,
      .connect     = llc_ui_connect,
      .socketpair  = sock_no_socketpair,
      .accept      = llc_ui_accept,
      .getname     = llc_ui_getname,
      .poll      = datagram_poll,
      .ioctl       = llc_ui_ioctl,
      .listen      = llc_ui_listen,
      .shutdown    = llc_ui_shutdown,
      .setsockopt  = llc_ui_setsockopt,
      .getsockopt  = llc_ui_getsockopt,
      .sendmsg     = llc_ui_sendmsg,
      .recvmsg     = llc_ui_recvmsg,
      .mmap      = sock_no_mmap,
      .sendpage    = sock_no_sendpage,
};

static char llc_proc_err_msg[] __initdata =
      KERN_CRIT "LLC: Unable to register the proc_fs entries\n";
static char llc_sysctl_err_msg[] __initdata =
      KERN_CRIT "LLC: Unable to register the sysctl entries\n";
static char llc_sock_err_msg[] __initdata =
      KERN_CRIT "LLC: Unable to register the network family\n";

static int __init llc2_init(void)
{
      int rc = proto_register(&llc_proto, 0);

      if (rc != 0)
            goto out;

      llc_build_offset_table();
      llc_station_init();
      llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
      rc = llc_proc_init();
      if (rc != 0) {
            printk(llc_proc_err_msg);
            goto out_unregister_llc_proto;
      }
      rc = llc_sysctl_init();
      if (rc) {
            printk(llc_sysctl_err_msg);
            goto out_proc;
      }
      rc = sock_register(&llc_ui_family_ops);
      if (rc) {
            printk(llc_sock_err_msg);
            goto out_sysctl;
      }
      llc_add_pack(LLC_DEST_SAP, llc_sap_handler);
      llc_add_pack(LLC_DEST_CONN, llc_conn_handler);
out:
      return rc;
out_sysctl:
      llc_sysctl_exit();
out_proc:
      llc_proc_exit();
out_unregister_llc_proto:
      proto_unregister(&llc_proto);
      goto out;
}

static void __exit llc2_exit(void)
{
      llc_station_exit();
      llc_remove_pack(LLC_DEST_SAP);
      llc_remove_pack(LLC_DEST_CONN);
      sock_unregister(PF_LLC);
      llc_proc_exit();
      llc_sysctl_exit();
      proto_unregister(&llc_proto);
}

module_init(llc2_init);
module_exit(llc2_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
MODULE_DESCRIPTION("IEEE 802.2 PF_LLC support");
MODULE_ALIAS_NETPROTO(PF_LLC);

Generated by  Doxygen 1.6.0   Back to index