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af_iucv.c

/*
 *  linux/net/iucv/af_iucv.c
 *
 *  IUCV protocol stack for Linux on zSeries
 *
 *  Copyright 2006 IBM Corporation
 *
 *  Author(s):    Jennifer Hunt <jenhunt@us.ibm.com>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <net/sock.h>
#include <asm/ebcdic.h>
#include <asm/cpcmd.h>
#include <linux/kmod.h>

#include <net/iucv/iucv.h>
#include <net/iucv/af_iucv.h>

#define CONFIG_IUCV_SOCK_DEBUG 1

#define IPRMDATA 0x80
#define VERSION "1.0"

static char iucv_userid[80];

static struct proto_ops iucv_sock_ops;

static struct proto iucv_proto = {
      .name       = "AF_IUCV",
      .owner            = THIS_MODULE,
      .obj_size   = sizeof(struct iucv_sock),
};

static void iucv_sock_kill(struct sock *sk);
static void iucv_sock_close(struct sock *sk);

/* Call Back functions */
static void iucv_callback_rx(struct iucv_path *, struct iucv_message *);
static void iucv_callback_txdone(struct iucv_path *, struct iucv_message *);
static void iucv_callback_connack(struct iucv_path *, u8 ipuser[16]);
static int iucv_callback_connreq(struct iucv_path *, u8 ipvmid[8],
                         u8 ipuser[16]);
static void iucv_callback_connrej(struct iucv_path *, u8 ipuser[16]);

static struct iucv_sock_list iucv_sk_list = {
      .lock = RW_LOCK_UNLOCKED,
      .autobind_name = ATOMIC_INIT(0)
};

static struct iucv_handler af_iucv_handler = {
      .path_pending       = iucv_callback_connreq,
      .path_complete      = iucv_callback_connack,
      .path_severed       = iucv_callback_connrej,
      .message_pending  = iucv_callback_rx,
      .message_complete = iucv_callback_txdone
};

static inline void high_nmcpy(unsigned char *dst, char *src)
{
       memcpy(dst, src, 8);
}

static inline void low_nmcpy(unsigned char *dst, char *src)
{
       memcpy(&dst[8], src, 8);
}

/* Timers */
static void iucv_sock_timeout(unsigned long arg)
{
      struct sock *sk = (struct sock *)arg;

      bh_lock_sock(sk);
      sk->sk_err = ETIMEDOUT;
      sk->sk_state_change(sk);
      bh_unlock_sock(sk);

      iucv_sock_kill(sk);
      sock_put(sk);
}

static void iucv_sock_clear_timer(struct sock *sk)
{
      sk_stop_timer(sk, &sk->sk_timer);
}

static void iucv_sock_init_timer(struct sock *sk)
{
      init_timer(&sk->sk_timer);
      sk->sk_timer.function = iucv_sock_timeout;
      sk->sk_timer.data = (unsigned long)sk;
}

static struct sock *__iucv_get_sock_by_name(char *nm)
{
      struct sock *sk;
      struct hlist_node *node;

      sk_for_each(sk, node, &iucv_sk_list.head)
            if (!memcmp(&iucv_sk(sk)->src_name, nm, 8))
                  return sk;

      return NULL;
}

static void iucv_sock_destruct(struct sock *sk)
{
      skb_queue_purge(&sk->sk_receive_queue);
      skb_queue_purge(&sk->sk_write_queue);
}

/* Cleanup Listen */
static void iucv_sock_cleanup_listen(struct sock *parent)
{
      struct sock *sk;

      /* Close non-accepted connections */
      while ((sk = iucv_accept_dequeue(parent, NULL))) {
            iucv_sock_close(sk);
            iucv_sock_kill(sk);
      }

      parent->sk_state = IUCV_CLOSED;
      sock_set_flag(parent, SOCK_ZAPPED);
}

/* Kill socket */
static void iucv_sock_kill(struct sock *sk)
{
      if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
            return;

      iucv_sock_unlink(&iucv_sk_list, sk);
      sock_set_flag(sk, SOCK_DEAD);
      sock_put(sk);
}

/* Close an IUCV socket */
static void iucv_sock_close(struct sock *sk)
{
      unsigned char user_data[16];
      struct iucv_sock *iucv = iucv_sk(sk);
      int err;
      unsigned long timeo;

      iucv_sock_clear_timer(sk);
      lock_sock(sk);

      switch (sk->sk_state) {
      case IUCV_LISTEN:
            iucv_sock_cleanup_listen(sk);
            break;

      case IUCV_CONNECTED:
      case IUCV_DISCONN:
            err = 0;

            sk->sk_state = IUCV_CLOSING;
            sk->sk_state_change(sk);

            if (!skb_queue_empty(&iucv->send_skb_q)) {
                  if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
                        timeo = sk->sk_lingertime;
                  else
                        timeo = IUCV_DISCONN_TIMEOUT;
                  err = iucv_sock_wait_state(sk, IUCV_CLOSED, 0, timeo);
            }

            sk->sk_state = IUCV_CLOSED;
            sk->sk_state_change(sk);

            if (iucv->path) {
                  low_nmcpy(user_data, iucv->src_name);
                  high_nmcpy(user_data, iucv->dst_name);
                  ASCEBC(user_data, sizeof(user_data));
                  err = iucv_path_sever(iucv->path, user_data);
                  iucv_path_free(iucv->path);
                  iucv->path = NULL;
            }

            sk->sk_err = ECONNRESET;
            sk->sk_state_change(sk);

            skb_queue_purge(&iucv->send_skb_q);
            skb_queue_purge(&iucv->backlog_skb_q);

            sock_set_flag(sk, SOCK_ZAPPED);
            break;

      default:
            sock_set_flag(sk, SOCK_ZAPPED);
            break;
      }

      release_sock(sk);
      iucv_sock_kill(sk);
}

static void iucv_sock_init(struct sock *sk, struct sock *parent)
{
      if (parent)
            sk->sk_type = parent->sk_type;
}

static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio)
{
      struct sock *sk;

      sk = sk_alloc(&init_net, PF_IUCV, prio, &iucv_proto);
      if (!sk)
            return NULL;

      sock_init_data(sock, sk);
      INIT_LIST_HEAD(&iucv_sk(sk)->accept_q);
      spin_lock_init(&iucv_sk(sk)->accept_q_lock);
      skb_queue_head_init(&iucv_sk(sk)->send_skb_q);
      INIT_LIST_HEAD(&iucv_sk(sk)->message_q.list);
      spin_lock_init(&iucv_sk(sk)->message_q.lock);
      skb_queue_head_init(&iucv_sk(sk)->backlog_skb_q);
      iucv_sk(sk)->send_tag = 0;

      sk->sk_destruct = iucv_sock_destruct;
      sk->sk_sndtimeo = IUCV_CONN_TIMEOUT;
      sk->sk_allocation = GFP_DMA;

      sock_reset_flag(sk, SOCK_ZAPPED);

      sk->sk_protocol = proto;
      sk->sk_state      = IUCV_OPEN;

      iucv_sock_init_timer(sk);

      iucv_sock_link(&iucv_sk_list, sk);
      return sk;
}

/* Create an IUCV socket */
static int iucv_sock_create(struct net *net, struct socket *sock, int protocol)
{
      struct sock *sk;

      if (sock->type != SOCK_STREAM)
            return -ESOCKTNOSUPPORT;

      sock->state = SS_UNCONNECTED;
      sock->ops = &iucv_sock_ops;

      sk = iucv_sock_alloc(sock, protocol, GFP_KERNEL);
      if (!sk)
            return -ENOMEM;

      iucv_sock_init(sk, NULL);

      return 0;
}

void iucv_sock_link(struct iucv_sock_list *l, struct sock *sk)
{
      write_lock_bh(&l->lock);
      sk_add_node(sk, &l->head);
      write_unlock_bh(&l->lock);
}

void iucv_sock_unlink(struct iucv_sock_list *l, struct sock *sk)
{
      write_lock_bh(&l->lock);
      sk_del_node_init(sk);
      write_unlock_bh(&l->lock);
}

void iucv_accept_enqueue(struct sock *parent, struct sock *sk)
{
      unsigned long flags;
      struct iucv_sock *par = iucv_sk(parent);

      sock_hold(sk);
      spin_lock_irqsave(&par->accept_q_lock, flags);
      list_add_tail(&iucv_sk(sk)->accept_q, &par->accept_q);
      spin_unlock_irqrestore(&par->accept_q_lock, flags);
      iucv_sk(sk)->parent = parent;
      parent->sk_ack_backlog++;
}

void iucv_accept_unlink(struct sock *sk)
{
      unsigned long flags;
      struct iucv_sock *par = iucv_sk(iucv_sk(sk)->parent);

      spin_lock_irqsave(&par->accept_q_lock, flags);
      list_del_init(&iucv_sk(sk)->accept_q);
      spin_unlock_irqrestore(&par->accept_q_lock, flags);
      iucv_sk(sk)->parent->sk_ack_backlog--;
      iucv_sk(sk)->parent = NULL;
      sock_put(sk);
}

struct sock *iucv_accept_dequeue(struct sock *parent, struct socket *newsock)
{
      struct iucv_sock *isk, *n;
      struct sock *sk;

      list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
            sk = (struct sock *) isk;
            lock_sock(sk);

            if (sk->sk_state == IUCV_CLOSED) {
                  iucv_accept_unlink(sk);
                  release_sock(sk);
                  continue;
            }

            if (sk->sk_state == IUCV_CONNECTED ||
                sk->sk_state == IUCV_SEVERED ||
                !newsock) {
                  iucv_accept_unlink(sk);
                  if (newsock)
                        sock_graft(sk, newsock);

                  if (sk->sk_state == IUCV_SEVERED)
                        sk->sk_state = IUCV_DISCONN;

                  release_sock(sk);
                  return sk;
            }

            release_sock(sk);
      }
      return NULL;
}

int iucv_sock_wait_state(struct sock *sk, int state, int state2,
                   unsigned long timeo)
{
      DECLARE_WAITQUEUE(wait, current);
      int err = 0;

      add_wait_queue(sk->sk_sleep, &wait);
      while (sk->sk_state != state && sk->sk_state != state2) {
            set_current_state(TASK_INTERRUPTIBLE);

            if (!timeo) {
                  err = -EAGAIN;
                  break;
            }

            if (signal_pending(current)) {
                  err = sock_intr_errno(timeo);
                  break;
            }

            release_sock(sk);
            timeo = schedule_timeout(timeo);
            lock_sock(sk);

            err = sock_error(sk);
            if (err)
                  break;
      }
      set_current_state(TASK_RUNNING);
      remove_wait_queue(sk->sk_sleep, &wait);
      return err;
}

/* Bind an unbound socket */
static int iucv_sock_bind(struct socket *sock, struct sockaddr *addr,
                    int addr_len)
{
      struct sockaddr_iucv *sa = (struct sockaddr_iucv *) addr;
      struct sock *sk = sock->sk;
      struct iucv_sock *iucv;
      int err;

      /* Verify the input sockaddr */
      if (!addr || addr->sa_family != AF_IUCV)
            return -EINVAL;

      lock_sock(sk);
      if (sk->sk_state != IUCV_OPEN) {
            err = -EBADFD;
            goto done;
      }

      write_lock_bh(&iucv_sk_list.lock);

      iucv = iucv_sk(sk);
      if (__iucv_get_sock_by_name(sa->siucv_name)) {
            err = -EADDRINUSE;
            goto done_unlock;
      }
      if (iucv->path) {
            err = 0;
            goto done_unlock;
      }

      /* Bind the socket */
      memcpy(iucv->src_name, sa->siucv_name, 8);

      /* Copy the user id */
      memcpy(iucv->src_user_id, iucv_userid, 8);
      sk->sk_state = IUCV_BOUND;
      err = 0;

done_unlock:
      /* Release the socket list lock */
      write_unlock_bh(&iucv_sk_list.lock);
done:
      release_sock(sk);
      return err;
}

/* Automatically bind an unbound socket */
static int iucv_sock_autobind(struct sock *sk)
{
      struct iucv_sock *iucv = iucv_sk(sk);
      char query_buffer[80];
      char name[12];
      int err = 0;

      /* Set the userid and name */
      cpcmd("QUERY USERID", query_buffer, sizeof(query_buffer), &err);
      if (unlikely(err))
            return -EPROTO;

      memcpy(iucv->src_user_id, query_buffer, 8);

      write_lock_bh(&iucv_sk_list.lock);

      sprintf(name, "%08x", atomic_inc_return(&iucv_sk_list.autobind_name));
      while (__iucv_get_sock_by_name(name)) {
            sprintf(name, "%08x",
                  atomic_inc_return(&iucv_sk_list.autobind_name));
      }

      write_unlock_bh(&iucv_sk_list.lock);

      memcpy(&iucv->src_name, name, 8);

      return err;
}

/* Connect an unconnected socket */
static int iucv_sock_connect(struct socket *sock, struct sockaddr *addr,
                       int alen, int flags)
{
      struct sockaddr_iucv *sa = (struct sockaddr_iucv *) addr;
      struct sock *sk = sock->sk;
      struct iucv_sock *iucv;
      unsigned char user_data[16];
      int err;

      if (addr->sa_family != AF_IUCV || alen < sizeof(struct sockaddr_iucv))
            return -EINVAL;

      if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
            return -EBADFD;

      if (sk->sk_type != SOCK_STREAM)
            return -EINVAL;

      iucv = iucv_sk(sk);

      if (sk->sk_state == IUCV_OPEN) {
            err = iucv_sock_autobind(sk);
            if (unlikely(err))
                  return err;
      }

      lock_sock(sk);

      /* Set the destination information */
      memcpy(iucv_sk(sk)->dst_user_id, sa->siucv_user_id, 8);
      memcpy(iucv_sk(sk)->dst_name, sa->siucv_name, 8);

      high_nmcpy(user_data, sa->siucv_name);
      low_nmcpy(user_data, iucv_sk(sk)->src_name);
      ASCEBC(user_data, sizeof(user_data));

      iucv = iucv_sk(sk);
      /* Create path. */
      iucv->path = iucv_path_alloc(IUCV_QUEUELEN_DEFAULT,
                             IPRMDATA, GFP_KERNEL);
      err = iucv_path_connect(iucv->path, &af_iucv_handler,
                        sa->siucv_user_id, NULL, user_data, sk);
      if (err) {
            iucv_path_free(iucv->path);
            iucv->path = NULL;
            err = -ECONNREFUSED;
            goto done;
      }

      if (sk->sk_state != IUCV_CONNECTED) {
            err = iucv_sock_wait_state(sk, IUCV_CONNECTED, IUCV_DISCONN,
                        sock_sndtimeo(sk, flags & O_NONBLOCK));
      }

      if (sk->sk_state == IUCV_DISCONN) {
            release_sock(sk);
            return -ECONNREFUSED;
      }
done:
      release_sock(sk);
      return err;
}

/* Move a socket into listening state. */
static int iucv_sock_listen(struct socket *sock, int backlog)
{
      struct sock *sk = sock->sk;
      int err;

      lock_sock(sk);

      err = -EINVAL;
      if (sk->sk_state != IUCV_BOUND || sock->type != SOCK_STREAM)
            goto done;

      sk->sk_max_ack_backlog = backlog;
      sk->sk_ack_backlog = 0;
      sk->sk_state = IUCV_LISTEN;
      err = 0;

done:
      release_sock(sk);
      return err;
}

/* Accept a pending connection */
static int iucv_sock_accept(struct socket *sock, struct socket *newsock,
                      int flags)
{
      DECLARE_WAITQUEUE(wait, current);
      struct sock *sk = sock->sk, *nsk;
      long timeo;
      int err = 0;

      lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

      if (sk->sk_state != IUCV_LISTEN) {
            err = -EBADFD;
            goto done;
      }

      timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

      /* Wait for an incoming connection */
      add_wait_queue_exclusive(sk->sk_sleep, &wait);
      while (!(nsk = iucv_accept_dequeue(sk, newsock))) {
            set_current_state(TASK_INTERRUPTIBLE);
            if (!timeo) {
                  err = -EAGAIN;
                  break;
            }

            release_sock(sk);
            timeo = schedule_timeout(timeo);
            lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

            if (sk->sk_state != IUCV_LISTEN) {
                  err = -EBADFD;
                  break;
            }

            if (signal_pending(current)) {
                  err = sock_intr_errno(timeo);
                  break;
            }
      }

      set_current_state(TASK_RUNNING);
      remove_wait_queue(sk->sk_sleep, &wait);

      if (err)
            goto done;

      newsock->state = SS_CONNECTED;

done:
      release_sock(sk);
      return err;
}

static int iucv_sock_getname(struct socket *sock, struct sockaddr *addr,
                       int *len, int peer)
{
      struct sockaddr_iucv *siucv = (struct sockaddr_iucv *) addr;
      struct sock *sk = sock->sk;

      addr->sa_family = AF_IUCV;
      *len = sizeof(struct sockaddr_iucv);

      if (peer) {
            memcpy(siucv->siucv_user_id, iucv_sk(sk)->dst_user_id, 8);
            memcpy(siucv->siucv_name, &iucv_sk(sk)->dst_name, 8);
      } else {
            memcpy(siucv->siucv_user_id, iucv_sk(sk)->src_user_id, 8);
            memcpy(siucv->siucv_name, iucv_sk(sk)->src_name, 8);
      }
      memset(&siucv->siucv_port, 0, sizeof(siucv->siucv_port));
      memset(&siucv->siucv_addr, 0, sizeof(siucv->siucv_addr));
      memset(siucv->siucv_nodeid, 0, sizeof(siucv->siucv_nodeid));

      return 0;
}

static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
                       struct msghdr *msg, size_t len)
{
      struct sock *sk = sock->sk;
      struct iucv_sock *iucv = iucv_sk(sk);
      struct sk_buff *skb;
      struct iucv_message txmsg;
      int err;

      err = sock_error(sk);
      if (err)
            return err;

      if (msg->msg_flags & MSG_OOB)
            return -EOPNOTSUPP;

      lock_sock(sk);

      if (sk->sk_shutdown & SEND_SHUTDOWN) {
            err = -EPIPE;
            goto out;
      }

      if (sk->sk_state == IUCV_CONNECTED) {
            if (!(skb = sock_alloc_send_skb(sk, len,
                                    msg->msg_flags & MSG_DONTWAIT,
                                    &err)))
                  goto out;

            if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
                  err = -EFAULT;
                  goto fail;
            }

            txmsg.class = 0;
            txmsg.tag = iucv->send_tag++;
            memcpy(skb->cb, &txmsg.tag, 4);
            skb_queue_tail(&iucv->send_skb_q, skb);
            err = iucv_message_send(iucv->path, &txmsg, 0, 0,
                              (void *) skb->data, skb->len);
            if (err) {
                  if (err == 3)
                        printk(KERN_ERR "AF_IUCV msg limit exceeded\n");
                  skb_unlink(skb, &iucv->send_skb_q);
                  err = -EPIPE;
                  goto fail;
            }

      } else {
            err = -ENOTCONN;
            goto out;
      }

      release_sock(sk);
      return len;

fail:
      kfree_skb(skb);
out:
      release_sock(sk);
      return err;
}

static int iucv_fragment_skb(struct sock *sk, struct sk_buff *skb, int len)
{
      int dataleft, size, copied = 0;
      struct sk_buff *nskb;

      dataleft = len;
      while (dataleft) {
            if (dataleft >= sk->sk_rcvbuf / 4)
                  size = sk->sk_rcvbuf / 4;
            else
                  size = dataleft;

            nskb = alloc_skb(size, GFP_ATOMIC | GFP_DMA);
            if (!nskb)
                  return -ENOMEM;

            memcpy(nskb->data, skb->data + copied, size);
            copied += size;
            dataleft -= size;

            skb_reset_transport_header(nskb);
            skb_reset_network_header(nskb);
            nskb->len = size;

            skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, nskb);
      }

      return 0;
}

static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
                         struct iucv_path *path,
                         struct iucv_message *msg)
{
      int rc;

      if (msg->flags & IPRMDATA) {
            skb->data = NULL;
            skb->len = 0;
      } else {
            rc = iucv_message_receive(path, msg, 0, skb->data,
                                msg->length, NULL);
            if (rc) {
                  kfree_skb(skb);
                  return;
            }
            if (skb->truesize >= sk->sk_rcvbuf / 4) {
                  rc = iucv_fragment_skb(sk, skb, msg->length);
                  kfree_skb(skb);
                  skb = NULL;
                  if (rc) {
                        iucv_path_sever(path, NULL);
                        return;
                  }
                  skb = skb_dequeue(&iucv_sk(sk)->backlog_skb_q);
            } else {
                  skb_reset_transport_header(skb);
                  skb_reset_network_header(skb);
                  skb->len = msg->length;
            }
      }

      if (sock_queue_rcv_skb(sk, skb))
            skb_queue_head(&iucv_sk(sk)->backlog_skb_q, skb);
}

static void iucv_process_message_q(struct sock *sk)
{
      struct iucv_sock *iucv = iucv_sk(sk);
      struct sk_buff *skb;
      struct sock_msg_q *p, *n;

      list_for_each_entry_safe(p, n, &iucv->message_q.list, list) {
            skb = alloc_skb(p->msg.length, GFP_ATOMIC | GFP_DMA);
            if (!skb)
                  break;
            iucv_process_message(sk, skb, p->path, &p->msg);
            list_del(&p->list);
            kfree(p);
            if (!skb_queue_empty(&iucv->backlog_skb_q))
                  break;
      }
}

static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
                       struct msghdr *msg, size_t len, int flags)
{
      int noblock = flags & MSG_DONTWAIT;
      struct sock *sk = sock->sk;
      struct iucv_sock *iucv = iucv_sk(sk);
      int target, copied = 0;
      struct sk_buff *skb, *rskb, *cskb;
      int err = 0;

      if ((sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED) &&
          skb_queue_empty(&iucv->backlog_skb_q) &&
          skb_queue_empty(&sk->sk_receive_queue) &&
          list_empty(&iucv->message_q.list))
            return 0;

      if (flags & (MSG_OOB))
            return -EOPNOTSUPP;

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

      skb = skb_recv_datagram(sk, flags, noblock, &err);
      if (!skb) {
            if (sk->sk_shutdown & RCV_SHUTDOWN)
                  return 0;
            return err;
      }

      copied = min_t(unsigned int, skb->len, len);

      cskb = skb;
      if (memcpy_toiovec(msg->msg_iov, cskb->data, copied)) {
            skb_queue_head(&sk->sk_receive_queue, skb);
            if (copied == 0)
                  return -EFAULT;
            goto done;
      }

      len -= copied;

      /* Mark read part of skb as used */
      if (!(flags & MSG_PEEK)) {
            skb_pull(skb, copied);

            if (skb->len) {
                  skb_queue_head(&sk->sk_receive_queue, skb);
                  goto done;
            }

            kfree_skb(skb);

            /* Queue backlog skbs */
            rskb = skb_dequeue(&iucv->backlog_skb_q);
            while (rskb) {
                  if (sock_queue_rcv_skb(sk, rskb)) {
                        skb_queue_head(&iucv->backlog_skb_q,
                                    rskb);
                        break;
                  } else {
                        rskb = skb_dequeue(&iucv->backlog_skb_q);
                  }
            }
            if (skb_queue_empty(&iucv->backlog_skb_q)) {
                  spin_lock_bh(&iucv->message_q.lock);
                  if (!list_empty(&iucv->message_q.list))
                        iucv_process_message_q(sk);
                  spin_unlock_bh(&iucv->message_q.lock);
            }

      } else
            skb_queue_head(&sk->sk_receive_queue, skb);

done:
      return err ? : copied;
}

static inline unsigned int iucv_accept_poll(struct sock *parent)
{
      struct iucv_sock *isk, *n;
      struct sock *sk;

      list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
            sk = (struct sock *) isk;

            if (sk->sk_state == IUCV_CONNECTED)
                  return POLLIN | POLLRDNORM;
      }

      return 0;
}

unsigned int iucv_sock_poll(struct file *file, struct socket *sock,
                      poll_table *wait)
{
      struct sock *sk = sock->sk;
      unsigned int mask = 0;

      poll_wait(file, sk->sk_sleep, wait);

      if (sk->sk_state == IUCV_LISTEN)
            return iucv_accept_poll(sk);

      if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
            mask |= POLLERR;

      if (sk->sk_shutdown & RCV_SHUTDOWN)
            mask |= POLLRDHUP;

      if (sk->sk_shutdown == SHUTDOWN_MASK)
            mask |= POLLHUP;

      if (!skb_queue_empty(&sk->sk_receive_queue) ||
          (sk->sk_shutdown & RCV_SHUTDOWN))
            mask |= POLLIN | POLLRDNORM;

      if (sk->sk_state == IUCV_CLOSED)
            mask |= POLLHUP;

      if (sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED)
            mask |= POLLIN;

      if (sock_writeable(sk))
            mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
      else
            set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

      return mask;
}

static int iucv_sock_shutdown(struct socket *sock, int how)
{
      struct sock *sk = sock->sk;
      struct iucv_sock *iucv = iucv_sk(sk);
      struct iucv_message txmsg;
      int err = 0;
      u8 prmmsg[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};

      how++;

      if ((how & ~SHUTDOWN_MASK) || !how)
            return -EINVAL;

      lock_sock(sk);
      switch (sk->sk_state) {
      case IUCV_CLOSED:
            err = -ENOTCONN;
            goto fail;

      default:
            sk->sk_shutdown |= how;
            break;
      }

      if (how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) {
            txmsg.class = 0;
            txmsg.tag = 0;
            err = iucv_message_send(iucv->path, &txmsg, IUCV_IPRMDATA, 0,
                              (void *) prmmsg, 8);
            if (err) {
                  switch (err) {
                  case 1:
                        err = -ENOTCONN;
                        break;
                  case 2:
                        err = -ECONNRESET;
                        break;
                  default:
                        err = -ENOTCONN;
                        break;
                  }
            }
      }

      if (how == RCV_SHUTDOWN || how == SHUTDOWN_MASK) {
            err = iucv_path_quiesce(iucv_sk(sk)->path, NULL);
            if (err)
                  err = -ENOTCONN;

            skb_queue_purge(&sk->sk_receive_queue);
      }

      /* Wake up anyone sleeping in poll */
      sk->sk_state_change(sk);

fail:
      release_sock(sk);
      return err;
}

static int iucv_sock_release(struct socket *sock)
{
      struct sock *sk = sock->sk;
      int err = 0;

      if (!sk)
            return 0;

      iucv_sock_close(sk);

      /* Unregister with IUCV base support */
      if (iucv_sk(sk)->path) {
            iucv_path_sever(iucv_sk(sk)->path, NULL);
            iucv_path_free(iucv_sk(sk)->path);
            iucv_sk(sk)->path = NULL;
      }

      sock_orphan(sk);
      iucv_sock_kill(sk);
      return err;
}

/* Callback wrappers - called from iucv base support */
static int iucv_callback_connreq(struct iucv_path *path,
                         u8 ipvmid[8], u8 ipuser[16])
{
      unsigned char user_data[16];
      unsigned char nuser_data[16];
      unsigned char src_name[8];
      struct hlist_node *node;
      struct sock *sk, *nsk;
      struct iucv_sock *iucv, *niucv;
      int err;

      memcpy(src_name, ipuser, 8);
      EBCASC(src_name, 8);
      /* Find out if this path belongs to af_iucv. */
      read_lock(&iucv_sk_list.lock);
      iucv = NULL;
      sk = NULL;
      sk_for_each(sk, node, &iucv_sk_list.head)
            if (sk->sk_state == IUCV_LISTEN &&
                !memcmp(&iucv_sk(sk)->src_name, src_name, 8)) {
                  /*
                   * Found a listening socket with
                   * src_name == ipuser[0-7].
                   */
                  iucv = iucv_sk(sk);
                  break;
            }
      read_unlock(&iucv_sk_list.lock);
      if (!iucv)
            /* No socket found, not one of our paths. */
            return -EINVAL;

      bh_lock_sock(sk);

      /* Check if parent socket is listening */
      low_nmcpy(user_data, iucv->src_name);
      high_nmcpy(user_data, iucv->dst_name);
      ASCEBC(user_data, sizeof(user_data));
      if (sk->sk_state != IUCV_LISTEN) {
            err = iucv_path_sever(path, user_data);
            goto fail;
      }

      /* Check for backlog size */
      if (sk_acceptq_is_full(sk)) {
            err = iucv_path_sever(path, user_data);
            goto fail;
      }

      /* Create the new socket */
      nsk = iucv_sock_alloc(NULL, SOCK_STREAM, GFP_ATOMIC);
      if (!nsk) {
            err = iucv_path_sever(path, user_data);
            goto fail;
      }

      niucv = iucv_sk(nsk);
      iucv_sock_init(nsk, sk);

      /* Set the new iucv_sock */
      memcpy(niucv->dst_name, ipuser + 8, 8);
      EBCASC(niucv->dst_name, 8);
      memcpy(niucv->dst_user_id, ipvmid, 8);
      memcpy(niucv->src_name, iucv->src_name, 8);
      memcpy(niucv->src_user_id, iucv->src_user_id, 8);
      niucv->path = path;

      /* Call iucv_accept */
      high_nmcpy(nuser_data, ipuser + 8);
      memcpy(nuser_data + 8, niucv->src_name, 8);
      ASCEBC(nuser_data + 8, 8);

      path->msglim = IUCV_QUEUELEN_DEFAULT;
      err = iucv_path_accept(path, &af_iucv_handler, nuser_data, nsk);
      if (err) {
            err = iucv_path_sever(path, user_data);
            goto fail;
      }

      iucv_accept_enqueue(sk, nsk);

      /* Wake up accept */
      nsk->sk_state = IUCV_CONNECTED;
      sk->sk_data_ready(sk, 1);
      err = 0;
fail:
      bh_unlock_sock(sk);
      return 0;
}

static void iucv_callback_connack(struct iucv_path *path, u8 ipuser[16])
{
      struct sock *sk = path->private;

      sk->sk_state = IUCV_CONNECTED;
      sk->sk_state_change(sk);
}

static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg)
{
      struct sock *sk = path->private;
      struct iucv_sock *iucv = iucv_sk(sk);
      struct sk_buff *skb;
      struct sock_msg_q *save_msg;
      int len;

      if (sk->sk_shutdown & RCV_SHUTDOWN)
            return;

      if (!list_empty(&iucv->message_q.list) ||
          !skb_queue_empty(&iucv->backlog_skb_q))
            goto save_message;

      len = atomic_read(&sk->sk_rmem_alloc);
      len += msg->length + sizeof(struct sk_buff);
      if (len > sk->sk_rcvbuf)
            goto save_message;

      skb = alloc_skb(msg->length, GFP_ATOMIC | GFP_DMA);
      if (!skb)
            goto save_message;

      spin_lock(&iucv->message_q.lock);
      iucv_process_message(sk, skb, path, msg);
      spin_unlock(&iucv->message_q.lock);

      return;

save_message:
      save_msg = kzalloc(sizeof(struct sock_msg_q), GFP_ATOMIC | GFP_DMA);
      save_msg->path = path;
      save_msg->msg = *msg;

      spin_lock(&iucv->message_q.lock);
      list_add_tail(&save_msg->list, &iucv->message_q.list);
      spin_unlock(&iucv->message_q.lock);
}

static void iucv_callback_txdone(struct iucv_path *path,
                         struct iucv_message *msg)
{
      struct sock *sk = path->private;
      struct sk_buff *this;
      struct sk_buff_head *list = &iucv_sk(sk)->send_skb_q;
      struct sk_buff *list_skb = list->next;
      unsigned long flags;

      if (list_skb) {
            spin_lock_irqsave(&list->lock, flags);

            do {
                  this = list_skb;
                  list_skb = list_skb->next;
            } while (memcmp(&msg->tag, this->cb, 4) && list_skb);

            spin_unlock_irqrestore(&list->lock, flags);

            skb_unlink(this, &iucv_sk(sk)->send_skb_q);
            kfree_skb(this);
      }

      if (sk->sk_state == IUCV_CLOSING) {
            if (skb_queue_empty(&iucv_sk(sk)->send_skb_q)) {
                  sk->sk_state = IUCV_CLOSED;
                  sk->sk_state_change(sk);
            }
      }

}

static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])
{
      struct sock *sk = path->private;

      if (!list_empty(&iucv_sk(sk)->accept_q))
            sk->sk_state = IUCV_SEVERED;
      else
            sk->sk_state = IUCV_DISCONN;

      sk->sk_state_change(sk);
}

static struct proto_ops iucv_sock_ops = {
      .family           = PF_IUCV,
      .owner            = THIS_MODULE,
      .release    = iucv_sock_release,
      .bind       = iucv_sock_bind,
      .connect    = iucv_sock_connect,
      .listen           = iucv_sock_listen,
      .accept           = iucv_sock_accept,
      .getname    = iucv_sock_getname,
      .sendmsg    = iucv_sock_sendmsg,
      .recvmsg    = iucv_sock_recvmsg,
      .poll       = iucv_sock_poll,
      .ioctl            = sock_no_ioctl,
      .mmap       = sock_no_mmap,
      .socketpair = sock_no_socketpair,
      .shutdown   = iucv_sock_shutdown,
      .setsockopt = sock_no_setsockopt,
      .getsockopt = sock_no_getsockopt
};

static struct net_proto_family iucv_sock_family_ops = {
      .family     = AF_IUCV,
      .owner      = THIS_MODULE,
      .create     = iucv_sock_create,
};

static int __init afiucv_init(void)
{
      int err;

      if (!MACHINE_IS_VM) {
            printk(KERN_ERR "AF_IUCV connection needs VM as base\n");
            err = -EPROTONOSUPPORT;
            goto out;
      }
      cpcmd("QUERY USERID", iucv_userid, sizeof(iucv_userid), &err);
      if (unlikely(err)) {
            printk(KERN_ERR "AF_IUCV needs the VM userid\n");
            err = -EPROTONOSUPPORT;
            goto out;
      }

      err = iucv_register(&af_iucv_handler, 0);
      if (err)
            goto out;
      err = proto_register(&iucv_proto, 0);
      if (err)
            goto out_iucv;
      err = sock_register(&iucv_sock_family_ops);
      if (err)
            goto out_proto;
      printk(KERN_INFO "AF_IUCV lowlevel driver initialized\n");
      return 0;

out_proto:
      proto_unregister(&iucv_proto);
out_iucv:
      iucv_unregister(&af_iucv_handler, 0);
out:
      return err;
}

static void __exit afiucv_exit(void)
{
      sock_unregister(PF_IUCV);
      proto_unregister(&iucv_proto);
      iucv_unregister(&af_iucv_handler, 0);

      printk(KERN_INFO "AF_IUCV lowlevel driver unloaded\n");
}

module_init(afiucv_init);
module_exit(afiucv_exit);

MODULE_AUTHOR("Jennifer Hunt <jenhunt@us.ibm.com>");
MODULE_DESCRIPTION("IUCV Sockets ver " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_IUCV);

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