Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2384 insertions, 0 deletions

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
new file mode 100644
index 000000000..e14368ced
--- /dev/null
+++ b/net/iucv/af_iucv.c
@@ -0,0 +1,2384 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  IUCV protocol stack for Linux on zSeries
+ *
+ *  Copyright IBM Corp. 2006, 2009
+ *
+ *  Author(s):	Jennifer Hunt <jenhunt@us.ibm.com>
+ *		Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
+ *  PM functions:
+ *		Ursula Braun <ursula.braun@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "af_iucv"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/limits.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/security.h>
+#include <net/sock.h>
+#include <asm/ebcdic.h>
+#include <asm/cpcmd.h>
+#include <linux/kmod.h>
+
+#include <net/iucv/af_iucv.h>
+
+#define VERSION "1.2"
+
+static char iucv_userid[80];
+
+static struct proto iucv_proto = {
+	.name		= "AF_IUCV",
+	.owner		= THIS_MODULE,
+	.obj_size	= sizeof(struct iucv_sock),
+};
+
+static struct iucv_interface *pr_iucv;
+
+/* special AF_IUCV IPRM messages */
+static const u8 iprm_shutdown[8] =
+	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
+
+#define TRGCLS_SIZE	sizeof_field(struct iucv_message, class)
+
+#define __iucv_sock_wait(sk, condition, timeo, ret)			\
+do {									\
+	DEFINE_WAIT(__wait);						\
+	long __timeo = timeo;						\
+	ret = 0;							\
+	prepare_to_wait(sk_sleep(sk), &__wait, TASK_INTERRUPTIBLE);	\
+	while (!(condition)) {						\
+		if (!__timeo) {						\
+			ret = -EAGAIN;					\
+			break;						\
+		}							\
+		if (signal_pending(current)) {				\
+			ret = sock_intr_errno(__timeo);			\
+			break;						\
+		}							\
+		release_sock(sk);					\
+		__timeo = schedule_timeout(__timeo);			\
+		lock_sock(sk);						\
+		ret = sock_error(sk);					\
+		if (ret)						\
+			break;						\
+	}								\
+	finish_wait(sk_sleep(sk), &__wait);				\
+} while (0)
+
+#define iucv_sock_wait(sk, condition, timeo)				\
+({									\
+	int __ret = 0;							\
+	if (!(condition))						\
+		__iucv_sock_wait(sk, condition, timeo, __ret);		\
+	__ret;								\
+})
+
+static struct sock *iucv_accept_dequeue(struct sock *parent,
+					struct socket *newsock);
+static void iucv_sock_kill(struct sock *sk);
+static void iucv_sock_close(struct sock *sk);
+
+static void afiucv_hs_callback_txnotify(struct sk_buff *, enum iucv_tx_notify);
+
+/* 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 *);
+static int iucv_callback_connreq(struct iucv_path *, u8 *, u8 *);
+static void iucv_callback_connrej(struct iucv_path *, u8 *);
+static void iucv_callback_shutdown(struct iucv_path *, u8 *);
+
+static struct iucv_sock_list iucv_sk_list = {
+	.lock = __RW_LOCK_UNLOCKED(iucv_sk_list.lock),
+	.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,
+	.path_quiesced	  = iucv_callback_shutdown,
+};
+
+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);
+}
+
+/**
+ * iucv_msg_length() - Returns the length of an iucv message.
+ * @msg:	Pointer to struct iucv_message, MUST NOT be NULL
+ *
+ * The function returns the length of the specified iucv message @msg of data
+ * stored in a buffer and of data stored in the parameter list (PRMDATA).
+ *
+ * For IUCV_IPRMDATA, AF_IUCV uses the following convention to transport socket
+ * data:
+ *	PRMDATA[0..6]	socket data (max 7 bytes);
+ *	PRMDATA[7]	socket data length value (len is 0xff - PRMDATA[7])
+ *
+ * The socket data length is computed by subtracting the socket data length
+ * value from 0xFF.
+ * If the socket data len is greater 7, then PRMDATA can be used for special
+ * notifications (see iucv_sock_shutdown); and further,
+ * if the socket data len is > 7, the function returns 8.
+ *
+ * Use this function to allocate socket buffers to store iucv message data.
+ */
+static inline size_t iucv_msg_length(struct iucv_message *msg)
+{
+	size_t datalen;
+
+	if (msg->flags & IUCV_IPRMDATA) {
+		datalen = 0xff - msg->rmmsg[7];
+		return (datalen < 8) ? datalen : 8;
+	}
+	return msg->length;
+}
+
+/**
+ * iucv_sock_in_state() - check for specific states
+ * @sk:		sock structure
+ * @state:	first iucv sk state
+ * @state:	second iucv sk state
+ *
+ * Returns true if the socket in either in the first or second state.
+ */
+static int iucv_sock_in_state(struct sock *sk, int state, int state2)
+{
+	return (sk->sk_state == state || sk->sk_state == state2);
+}
+
+/**
+ * iucv_below_msglim() - function to check if messages can be sent
+ * @sk:		sock structure
+ *
+ * Returns true if the send queue length is lower than the message limit.
+ * Always returns true if the socket is not connected (no iucv path for
+ * checking the message limit).
+ */
+static inline int iucv_below_msglim(struct sock *sk)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	if (sk->sk_state != IUCV_CONNECTED)
+		return 1;
+	if (iucv->transport == AF_IUCV_TRANS_IUCV)
+		return (skb_queue_len(&iucv->send_skb_q) < iucv->path->msglim);
+	else
+		return ((atomic_read(&iucv->msg_sent) < iucv->msglimit_peer) &&
+			(atomic_read(&iucv->pendings) <= 0));
+}
+
+/**
+ * iucv_sock_wake_msglim() - Wake up thread waiting on msg limit
+ */
+static void iucv_sock_wake_msglim(struct sock *sk)
+{
+	struct socket_wq *wq;
+
+	rcu_read_lock();
+	wq = rcu_dereference(sk->sk_wq);
+	if (skwq_has_sleeper(wq))
+		wake_up_interruptible_all(&wq->wait);
+	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
+	rcu_read_unlock();
+}
+
+/**
+ * afiucv_hs_send() - send a message through HiperSockets transport
+ */
+static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock,
+		   struct sk_buff *skb, u8 flags)
+{
+	struct iucv_sock *iucv = iucv_sk(sock);
+	struct af_iucv_trans_hdr *phs_hdr;
+	struct sk_buff *nskb;
+	int err, confirm_recv = 0;
+
+	phs_hdr = skb_push(skb, sizeof(*phs_hdr));
+	memset(phs_hdr, 0, sizeof(*phs_hdr));
+	skb_reset_network_header(skb);
+
+	phs_hdr->magic = ETH_P_AF_IUCV;
+	phs_hdr->version = 1;
+	phs_hdr->flags = flags;
+	if (flags == AF_IUCV_FLAG_SYN)
+		phs_hdr->window = iucv->msglimit;
+	else if ((flags == AF_IUCV_FLAG_WIN) || !flags) {
+		confirm_recv = atomic_read(&iucv->msg_recv);
+		phs_hdr->window = confirm_recv;
+		if (confirm_recv)
+			phs_hdr->flags = phs_hdr->flags | AF_IUCV_FLAG_WIN;
+	}
+	memcpy(phs_hdr->destUserID, iucv->dst_user_id, 8);
+	memcpy(phs_hdr->destAppName, iucv->dst_name, 8);
+	memcpy(phs_hdr->srcUserID, iucv->src_user_id, 8);
+	memcpy(phs_hdr->srcAppName, iucv->src_name, 8);
+	ASCEBC(phs_hdr->destUserID, sizeof(phs_hdr->destUserID));
+	ASCEBC(phs_hdr->destAppName, sizeof(phs_hdr->destAppName));
+	ASCEBC(phs_hdr->srcUserID, sizeof(phs_hdr->srcUserID));
+	ASCEBC(phs_hdr->srcAppName, sizeof(phs_hdr->srcAppName));
+	if (imsg)
+		memcpy(&phs_hdr->iucv_hdr, imsg, sizeof(struct iucv_message));
+
+	skb->dev = iucv->hs_dev;
+	if (!skb->dev) {
+		err = -ENODEV;
+		goto err_free;
+	}
+
+	dev_hard_header(skb, skb->dev, ETH_P_AF_IUCV, NULL, NULL, skb->len);
+
+	if (!(skb->dev->flags & IFF_UP) || !netif_carrier_ok(skb->dev)) {
+		err = -ENETDOWN;
+		goto err_free;
+	}
+	if (skb->len > skb->dev->mtu) {
+		if (sock->sk_type == SOCK_SEQPACKET) {
+			err = -EMSGSIZE;
+			goto err_free;
+		}
+		skb_trim(skb, skb->dev->mtu);
+	}
+	skb->protocol = cpu_to_be16(ETH_P_AF_IUCV);
+
+	__skb_header_release(skb);
+	nskb = skb_clone(skb, GFP_ATOMIC);
+	if (!nskb) {
+		err = -ENOMEM;
+		goto err_free;
+	}
+
+	skb_queue_tail(&iucv->send_skb_q, nskb);
+	err = dev_queue_xmit(skb);
+	if (net_xmit_eval(err)) {
+		skb_unlink(nskb, &iucv->send_skb_q);
+		kfree_skb(nskb);
+	} else {
+		atomic_sub(confirm_recv, &iucv->msg_recv);
+		WARN_ON(atomic_read(&iucv->msg_recv) < 0);
+	}
+	return net_xmit_eval(err);
+
+err_free:
+	kfree_skb(skb);
+	return err;
+}
+
+static struct sock *__iucv_get_sock_by_name(char *nm)
+{
+	struct sock *sk;
+
+	sk_for_each(sk, &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_error_queue);
+
+	sk_mem_reclaim(sk);
+
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		pr_err("Attempt to release alive iucv socket %p\n", sk);
+		return;
+	}
+
+	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
+	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
+	WARN_ON(sk->sk_wmem_queued);
+	WARN_ON(sk->sk_forward_alloc);
+}
+
+/* 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;
+}
+
+static 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);
+}
+
+static 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);
+}
+
+/* Kill socket (only if zapped and orphaned) */
+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);
+}
+
+/* Terminate an IUCV path */
+static void iucv_sever_path(struct sock *sk, int with_user_data)
+{
+	unsigned char user_data[16];
+	struct iucv_sock *iucv = iucv_sk(sk);
+	struct iucv_path *path = iucv->path;
+
+	if (iucv->path) {
+		iucv->path = NULL;
+		if (with_user_data) {
+			low_nmcpy(user_data, iucv->src_name);
+			high_nmcpy(user_data, iucv->dst_name);
+			ASCEBC(user_data, sizeof(user_data));
+			pr_iucv->path_sever(path, user_data);
+		} else
+			pr_iucv->path_sever(path, NULL);
+		iucv_path_free(path);
+	}
+}
+
+/* Send controlling flags through an IUCV socket for HIPER transport */
+static int iucv_send_ctrl(struct sock *sk, u8 flags)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+	int err = 0;
+	int blen;
+	struct sk_buff *skb;
+	u8 shutdown = 0;
+
+	blen = sizeof(struct af_iucv_trans_hdr) +
+	       LL_RESERVED_SPACE(iucv->hs_dev);
+	if (sk->sk_shutdown & SEND_SHUTDOWN) {
+		/* controlling flags should be sent anyway */
+		shutdown = sk->sk_shutdown;
+		sk->sk_shutdown &= RCV_SHUTDOWN;
+	}
+	skb = sock_alloc_send_skb(sk, blen, 1, &err);
+	if (skb) {
+		skb_reserve(skb, blen);
+		err = afiucv_hs_send(NULL, sk, skb, flags);
+	}
+	if (shutdown)
+		sk->sk_shutdown = shutdown;
+	return err;
+}
+
+/* Close an IUCV socket */
+static void iucv_sock_close(struct sock *sk)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+	unsigned long timeo;
+	int err = 0;
+
+	lock_sock(sk);
+
+	switch (sk->sk_state) {
+	case IUCV_LISTEN:
+		iucv_sock_cleanup_listen(sk);
+		break;
+
+	case IUCV_CONNECTED:
+		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
+			err = iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN);
+			sk->sk_state = IUCV_DISCONN;
+			sk->sk_state_change(sk);
+		}
+		fallthrough;
+
+	case IUCV_DISCONN:
+		sk->sk_state = IUCV_CLOSING;
+		sk->sk_state_change(sk);
+
+		if (!err && !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;
+			iucv_sock_wait(sk,
+					iucv_sock_in_state(sk, IUCV_CLOSED, 0),
+					timeo);
+		}
+		fallthrough;
+
+	case IUCV_CLOSING:
+		sk->sk_state = IUCV_CLOSED;
+		sk->sk_state_change(sk);
+
+		sk->sk_err = ECONNRESET;
+		sk->sk_state_change(sk);
+
+		skb_queue_purge(&iucv->send_skb_q);
+		skb_queue_purge(&iucv->backlog_skb_q);
+		fallthrough;
+
+	default:
+		iucv_sever_path(sk, 1);
+	}
+
+	if (iucv->hs_dev) {
+		dev_put(iucv->hs_dev);
+		iucv->hs_dev = NULL;
+		sk->sk_bound_dev_if = 0;
+	}
+
+	/* mark socket for deletion by iucv_sock_kill() */
+	sock_set_flag(sk, SOCK_ZAPPED);
+
+	release_sock(sk);
+}
+
+static void iucv_sock_init(struct sock *sk, struct sock *parent)
+{
+	if (parent) {
+		sk->sk_type = parent->sk_type;
+		security_sk_clone(parent, sk);
+	}
+}
+
+static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio, int kern)
+{
+	struct sock *sk;
+	struct iucv_sock *iucv;
+
+	sk = sk_alloc(&init_net, PF_IUCV, prio, &iucv_proto, kern);
+	if (!sk)
+		return NULL;
+	iucv = iucv_sk(sk);
+
+	sock_init_data(sock, sk);
+	INIT_LIST_HEAD(&iucv->accept_q);
+	spin_lock_init(&iucv->accept_q_lock);
+	skb_queue_head_init(&iucv->send_skb_q);
+	INIT_LIST_HEAD(&iucv->message_q.list);
+	spin_lock_init(&iucv->message_q.lock);
+	skb_queue_head_init(&iucv->backlog_skb_q);
+	iucv->send_tag = 0;
+	atomic_set(&iucv->pendings, 0);
+	iucv->flags = 0;
+	iucv->msglimit = 0;
+	atomic_set(&iucv->msg_sent, 0);
+	atomic_set(&iucv->msg_recv, 0);
+	iucv->path = NULL;
+	iucv->sk_txnotify = afiucv_hs_callback_txnotify;
+	memset(&iucv->src_user_id , 0, 32);
+	if (pr_iucv)
+		iucv->transport = AF_IUCV_TRANS_IUCV;
+	else
+		iucv->transport = AF_IUCV_TRANS_HIPER;
+
+	sk->sk_destruct = iucv_sock_destruct;
+	sk->sk_sndtimeo = IUCV_CONN_TIMEOUT;
+
+	sock_reset_flag(sk, SOCK_ZAPPED);
+
+	sk->sk_protocol = proto;
+	sk->sk_state	= IUCV_OPEN;
+
+	iucv_sock_link(&iucv_sk_list, sk);
+	return sk;
+}
+
+static 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;
+	sk_acceptq_added(parent);
+}
+
+static 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);
+	sk_acceptq_removed(iucv_sk(sk)->parent);
+	iucv_sk(sk)->parent = NULL;
+	sock_put(sk);
+}
+
+static 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_DISCONN ||
+		    !newsock) {
+			iucv_accept_unlink(sk);
+			if (newsock)
+				sock_graft(sk, newsock);
+
+			release_sock(sk);
+			return sk;
+		}
+
+		release_sock(sk);
+	}
+	return NULL;
+}
+
+static void __iucv_auto_name(struct iucv_sock *iucv)
+{
+	char name[12];
+
+	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));
+	}
+	memcpy(iucv->src_name, name, 8);
+}
+
+/* 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;
+	char uid[sizeof(sa->siucv_user_id)];
+	struct sock *sk = sock->sk;
+	struct iucv_sock *iucv;
+	int err = 0;
+	struct net_device *dev;
+
+	/* Verify the input sockaddr */
+	if (addr_len < sizeof(struct sockaddr_iucv) ||
+	    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)
+		goto done_unlock;
+
+	/* Bind the socket */
+	if (pr_iucv)
+		if (!memcmp(sa->siucv_user_id, iucv_userid, 8))
+			goto vm_bind; /* VM IUCV transport */
+
+	/* try hiper transport */
+	memcpy(uid, sa->siucv_user_id, sizeof(uid));
+	ASCEBC(uid, 8);
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, dev) {
+		if (!memcmp(dev->perm_addr, uid, 8)) {
+			memcpy(iucv->src_user_id, sa->siucv_user_id, 8);
+			/* Check for unitialized siucv_name */
+			if (strncmp(sa->siucv_name, "        ", 8) == 0)
+				__iucv_auto_name(iucv);
+			else
+				memcpy(iucv->src_name, sa->siucv_name, 8);
+			sk->sk_bound_dev_if = dev->ifindex;
+			iucv->hs_dev = dev;
+			dev_hold(dev);
+			sk->sk_state = IUCV_BOUND;
+			iucv->transport = AF_IUCV_TRANS_HIPER;
+			if (!iucv->msglimit)
+				iucv->msglimit = IUCV_HIPER_MSGLIM_DEFAULT;
+			rcu_read_unlock();
+			goto done_unlock;
+		}
+	}
+	rcu_read_unlock();
+vm_bind:
+	if (pr_iucv) {
+		/* use local userid for backward compat */
+		memcpy(iucv->src_name, sa->siucv_name, 8);
+		memcpy(iucv->src_user_id, iucv_userid, 8);
+		sk->sk_state = IUCV_BOUND;
+		iucv->transport = AF_IUCV_TRANS_IUCV;
+		sk->sk_allocation |= GFP_DMA;
+		if (!iucv->msglimit)
+			iucv->msglimit = IUCV_QUEUELEN_DEFAULT;
+		goto done_unlock;
+	}
+	/* found no dev to bind */
+	err = -ENODEV;
+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);
+	int err = 0;
+
+	if (unlikely(!pr_iucv))
+		return -EPROTO;
+
+	memcpy(iucv->src_user_id, iucv_userid, 8);
+	iucv->transport = AF_IUCV_TRANS_IUCV;
+	sk->sk_allocation |= GFP_DMA;
+
+	write_lock_bh(&iucv_sk_list.lock);
+	__iucv_auto_name(iucv);
+	write_unlock_bh(&iucv_sk_list.lock);
+
+	if (!iucv->msglimit)
+		iucv->msglimit = IUCV_QUEUELEN_DEFAULT;
+
+	return err;
+}
+
+static int afiucv_path_connect(struct socket *sock, struct sockaddr *addr)
+{
+	struct sockaddr_iucv *sa = (struct sockaddr_iucv *) addr;
+	struct sock *sk = sock->sk;
+	struct iucv_sock *iucv = iucv_sk(sk);
+	unsigned char user_data[16];
+	int err;
+
+	high_nmcpy(user_data, sa->siucv_name);
+	low_nmcpy(user_data, iucv->src_name);
+	ASCEBC(user_data, sizeof(user_data));
+
+	/* Create path. */
+	iucv->path = iucv_path_alloc(iucv->msglimit,
+				     IUCV_IPRMDATA, GFP_KERNEL);
+	if (!iucv->path) {
+		err = -ENOMEM;
+		goto done;
+	}
+	err = pr_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;
+		switch (err) {
+		case 0x0b:	/* Target communicator is not logged on */
+			err = -ENETUNREACH;
+			break;
+		case 0x0d:	/* Max connections for this guest exceeded */
+		case 0x0e:	/* Max connections for target guest exceeded */
+			err = -EAGAIN;
+			break;
+		case 0x0f:	/* Missing IUCV authorization */
+			err = -EACCES;
+			break;
+		default:
+			err = -ECONNREFUSED;
+			break;
+		}
+	}
+done:
+	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 = iucv_sk(sk);
+	int err;
+
+	if (alen < sizeof(struct sockaddr_iucv) || addr->sa_family != AF_IUCV)
+		return -EINVAL;
+
+	if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
+		return -EBADFD;
+
+	if (sk->sk_state == IUCV_OPEN &&
+	    iucv->transport == AF_IUCV_TRANS_HIPER)
+		return -EBADFD; /* explicit bind required */
+
+	if (sk->sk_type != SOCK_STREAM && sk->sk_type != SOCK_SEQPACKET)
+		return -EINVAL;
+
+	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->dst_user_id, sa->siucv_user_id, 8);
+	memcpy(iucv->dst_name, sa->siucv_name, 8);
+
+	if (iucv->transport == AF_IUCV_TRANS_HIPER)
+		err = iucv_send_ctrl(sock->sk, AF_IUCV_FLAG_SYN);
+	else
+		err = afiucv_path_connect(sock, addr);
+	if (err)
+		goto done;
+
+	if (sk->sk_state != IUCV_CONNECTED)
+		err = iucv_sock_wait(sk, iucv_sock_in_state(sk, IUCV_CONNECTED,
+							    IUCV_DISCONN),
+				     sock_sndtimeo(sk, flags & O_NONBLOCK));
+
+	if (sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_CLOSED)
+		err = -ECONNREFUSED;
+
+	if (err && iucv->transport == AF_IUCV_TRANS_IUCV)
+		iucv_sever_path(sk, 0);
+
+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)
+		goto done;
+
+	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
+		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, bool kern)
+{
+	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_sleep(sk), &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_sleep(sk), &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 peer)
+{
+	struct sockaddr_iucv *siucv = (struct sockaddr_iucv *) addr;
+	struct sock *sk = sock->sk;
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	addr->sa_family = AF_IUCV;
+
+	if (peer) {
+		memcpy(siucv->siucv_user_id, iucv->dst_user_id, 8);
+		memcpy(siucv->siucv_name, iucv->dst_name, 8);
+	} else {
+		memcpy(siucv->siucv_user_id, iucv->src_user_id, 8);
+		memcpy(siucv->siucv_name, iucv->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 sizeof(struct sockaddr_iucv);
+}
+
+/**
+ * iucv_send_iprm() - Send socket data in parameter list of an iucv message.
+ * @path:	IUCV path
+ * @msg:	Pointer to a struct iucv_message
+ * @skb:	The socket data to send, skb->len MUST BE <= 7
+ *
+ * Send the socket data in the parameter list in the iucv message
+ * (IUCV_IPRMDATA). The socket data is stored at index 0 to 6 in the parameter
+ * list and the socket data len at index 7 (last byte).
+ * See also iucv_msg_length().
+ *
+ * Returns the error code from the iucv_message_send() call.
+ */
+static int iucv_send_iprm(struct iucv_path *path, struct iucv_message *msg,
+			  struct sk_buff *skb)
+{
+	u8 prmdata[8];
+
+	memcpy(prmdata, (void *) skb->data, skb->len);
+	prmdata[7] = 0xff - (u8) skb->len;
+	return pr_iucv->message_send(path, msg, IUCV_IPRMDATA, 0,
+				 (void *) prmdata, 8);
+}
+
+static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
+			     size_t len)
+{
+	struct sock *sk = sock->sk;
+	struct iucv_sock *iucv = iucv_sk(sk);
+	size_t headroom = 0;
+	size_t linear;
+	struct sk_buff *skb;
+	struct iucv_message txmsg = {0};
+	struct cmsghdr *cmsg;
+	int cmsg_done;
+	long timeo;
+	char user_id[9];
+	char appl_id[9];
+	int err;
+	int noblock = msg->msg_flags & MSG_DONTWAIT;
+
+	err = sock_error(sk);
+	if (err)
+		return err;
+
+	if (msg->msg_flags & MSG_OOB)
+		return -EOPNOTSUPP;
+
+	/* SOCK_SEQPACKET: we do not support segmented records */
+	if (sk->sk_type == SOCK_SEQPACKET && !(msg->msg_flags & MSG_EOR))
+		return -EOPNOTSUPP;
+
+	lock_sock(sk);
+
+	if (sk->sk_shutdown & SEND_SHUTDOWN) {
+		err = -EPIPE;
+		goto out;
+	}
+
+	/* Return if the socket is not in connected state */
+	if (sk->sk_state != IUCV_CONNECTED) {
+		err = -ENOTCONN;
+		goto out;
+	}
+
+	/* initialize defaults */
+	cmsg_done   = 0;	/* check for duplicate headers */
+
+	/* iterate over control messages */
+	for_each_cmsghdr(cmsg, msg) {
+		if (!CMSG_OK(msg, cmsg)) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (cmsg->cmsg_level != SOL_IUCV)
+			continue;
+
+		if (cmsg->cmsg_type & cmsg_done) {
+			err = -EINVAL;
+			goto out;
+		}
+		cmsg_done |= cmsg->cmsg_type;
+
+		switch (cmsg->cmsg_type) {
+		case SCM_IUCV_TRGCLS:
+			if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
+				err = -EINVAL;
+				goto out;
+			}
+
+			/* set iucv message target class */
+			memcpy(&txmsg.class,
+				(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
+
+			break;
+
+		default:
+			err = -EINVAL;
+			goto out;
+		}
+	}
+
+	/* allocate one skb for each iucv message:
+	 * this is fine for SOCK_SEQPACKET (unless we want to support
+	 * segmented records using the MSG_EOR flag), but
+	 * for SOCK_STREAM we might want to improve it in future */
+	if (iucv->transport == AF_IUCV_TRANS_HIPER) {
+		headroom = sizeof(struct af_iucv_trans_hdr) +
+			   LL_RESERVED_SPACE(iucv->hs_dev);
+		linear = len;
+	} else {
+		if (len < PAGE_SIZE) {
+			linear = len;
+		} else {
+			/* In nonlinear "classic" iucv skb,
+			 * reserve space for iucv_array
+			 */
+			headroom = sizeof(struct iucv_array) *
+				   (MAX_SKB_FRAGS + 1);
+			linear = PAGE_SIZE - headroom;
+		}
+	}
+	skb = sock_alloc_send_pskb(sk, headroom + linear, len - linear,
+				   noblock, &err, 0);
+	if (!skb)
+		goto out;
+	if (headroom)
+		skb_reserve(skb, headroom);
+	skb_put(skb, linear);
+	skb->len = len;
+	skb->data_len = len - linear;
+	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
+	if (err)
+		goto fail;
+
+	/* wait if outstanding messages for iucv path has reached */
+	timeo = sock_sndtimeo(sk, noblock);
+	err = iucv_sock_wait(sk, iucv_below_msglim(sk), timeo);
+	if (err)
+		goto fail;
+
+	/* return -ECONNRESET if the socket is no longer connected */
+	if (sk->sk_state != IUCV_CONNECTED) {
+		err = -ECONNRESET;
+		goto fail;
+	}
+
+	/* increment and save iucv message tag for msg_completion cbk */
+	txmsg.tag = iucv->send_tag++;
+	IUCV_SKB_CB(skb)->tag = txmsg.tag;
+
+	if (iucv->transport == AF_IUCV_TRANS_HIPER) {
+		atomic_inc(&iucv->msg_sent);
+		err = afiucv_hs_send(&txmsg, sk, skb, 0);
+		if (err) {
+			atomic_dec(&iucv->msg_sent);
+			goto out;
+		}
+	} else { /* Classic VM IUCV transport */
+		skb_queue_tail(&iucv->send_skb_q, skb);
+
+		if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) &&
+		    skb->len <= 7) {
+			err = iucv_send_iprm(iucv->path, &txmsg, skb);
+
+			/* on success: there is no message_complete callback */
+			/* for an IPRMDATA msg; remove skb from send queue   */
+			if (err == 0) {
+				skb_unlink(skb, &iucv->send_skb_q);
+				kfree_skb(skb);
+			}
+
+			/* this error should never happen since the	*/
+			/* IUCV_IPRMDATA path flag is set... sever path */
+			if (err == 0x15) {
+				pr_iucv->path_sever(iucv->path, NULL);
+				skb_unlink(skb, &iucv->send_skb_q);
+				err = -EPIPE;
+				goto fail;
+			}
+		} else if (skb_is_nonlinear(skb)) {
+			struct iucv_array *iba = (struct iucv_array *)skb->head;
+			int i;
+
+			/* skip iucv_array lying in the headroom */
+			iba[0].address = (u32)(addr_t)skb->data;
+			iba[0].length = (u32)skb_headlen(skb);
+			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+				iba[i + 1].address =
+					(u32)(addr_t)skb_frag_address(frag);
+				iba[i + 1].length = (u32)skb_frag_size(frag);
+			}
+			err = pr_iucv->message_send(iucv->path, &txmsg,
+						    IUCV_IPBUFLST, 0,
+						    (void *)iba, skb->len);
+		} else { /* non-IPRM Linear skb */
+			err = pr_iucv->message_send(iucv->path, &txmsg,
+					0, 0, (void *)skb->data, skb->len);
+		}
+		if (err) {
+			if (err == 3) {
+				user_id[8] = 0;
+				memcpy(user_id, iucv->dst_user_id, 8);
+				appl_id[8] = 0;
+				memcpy(appl_id, iucv->dst_name, 8);
+				pr_err(
+		"Application %s on z/VM guest %s exceeds message limit\n",
+					appl_id, user_id);
+				err = -EAGAIN;
+			} else {
+				err = -EPIPE;
+			}
+			skb_unlink(skb, &iucv->send_skb_q);
+			goto fail;
+		}
+	}
+
+	release_sock(sk);
+	return len;
+
+fail:
+	kfree_skb(skb);
+out:
+	release_sock(sk);
+	return err;
+}
+
+static struct sk_buff *alloc_iucv_recv_skb(unsigned long len)
+{
+	size_t headroom, linear;
+	struct sk_buff *skb;
+	int err;
+
+	if (len < PAGE_SIZE) {
+		headroom = 0;
+		linear = len;
+	} else {
+		headroom = sizeof(struct iucv_array) * (MAX_SKB_FRAGS + 1);
+		linear = PAGE_SIZE - headroom;
+	}
+	skb = alloc_skb_with_frags(headroom + linear, len - linear,
+				   0, &err, GFP_ATOMIC | GFP_DMA);
+	WARN_ONCE(!skb,
+		  "alloc of recv iucv skb len=%lu failed with errcode=%d\n",
+		  len, err);
+	if (skb) {
+		if (headroom)
+			skb_reserve(skb, headroom);
+		skb_put(skb, linear);
+		skb->len = len;
+		skb->data_len = len - linear;
+	}
+	return skb;
+}
+
+/* iucv_process_message() - Receive a single outstanding IUCV message
+ *
+ * Locking: must be called with message_q.lock held
+ */
+static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
+				 struct iucv_path *path,
+				 struct iucv_message *msg)
+{
+	int rc;
+	unsigned int len;
+
+	len = iucv_msg_length(msg);
+
+	/* store msg target class in the second 4 bytes of skb ctrl buffer */
+	/* Note: the first 4 bytes are reserved for msg tag */
+	IUCV_SKB_CB(skb)->class = msg->class;
+
+	/* check for special IPRM messages (e.g. iucv_sock_shutdown) */
+	if ((msg->flags & IUCV_IPRMDATA) && len > 7) {
+		if (memcmp(msg->rmmsg, iprm_shutdown, 8) == 0) {
+			skb->data = NULL;
+			skb->len = 0;
+		}
+	} else {
+		if (skb_is_nonlinear(skb)) {
+			struct iucv_array *iba = (struct iucv_array *)skb->head;
+			int i;
+
+			iba[0].address = (u32)(addr_t)skb->data;
+			iba[0].length = (u32)skb_headlen(skb);
+			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+				iba[i + 1].address =
+					(u32)(addr_t)skb_frag_address(frag);
+				iba[i + 1].length = (u32)skb_frag_size(frag);
+			}
+			rc = pr_iucv->message_receive(path, msg,
+					      IUCV_IPBUFLST,
+					      (void *)iba, len, NULL);
+		} else {
+			rc = pr_iucv->message_receive(path, msg,
+					      msg->flags & IUCV_IPRMDATA,
+					      skb->data, len, NULL);
+		}
+		if (rc) {
+			kfree_skb(skb);
+			return;
+		}
+		WARN_ON_ONCE(skb->len != len);
+	}
+
+	IUCV_SKB_CB(skb)->offset = 0;
+	if (sk_filter(sk, skb)) {
+		atomic_inc(&sk->sk_drops);	/* skb rejected by filter */
+		kfree_skb(skb);
+		return;
+	}
+	if (__sock_queue_rcv_skb(sk, skb))	/* handle rcv queue full */
+		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
+}
+
+/* iucv_process_message_q() - Process outstanding IUCV messages
+ *
+ * Locking: must be called with message_q.lock held
+ */
+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_iucv_recv_skb(iucv_msg_length(&p->msg));
+		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 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);
+	unsigned int copied, rlen;
+	struct sk_buff *skb, *rskb, *cskb;
+	int err = 0;
+	u32 offset;
+
+	if ((sk->sk_state == IUCV_DISCONN) &&
+	    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;
+
+	/* receive/dequeue next skb:
+	 * the function understands MSG_PEEK and, thus, does not dequeue skb */
+	skb = skb_recv_datagram(sk, flags, noblock, &err);
+	if (!skb) {
+		if (sk->sk_shutdown & RCV_SHUTDOWN)
+			return 0;
+		return err;
+	}
+
+	offset = IUCV_SKB_CB(skb)->offset;
+	rlen   = skb->len - offset;		/* real length of skb */
+	copied = min_t(unsigned int, rlen, len);
+	if (!rlen)
+		sk->sk_shutdown = sk->sk_shutdown | RCV_SHUTDOWN;
+
+	cskb = skb;
+	if (skb_copy_datagram_msg(cskb, offset, msg, copied)) {
+		if (!(flags & MSG_PEEK))
+			skb_queue_head(&sk->sk_receive_queue, skb);
+		return -EFAULT;
+	}
+
+	/* SOCK_SEQPACKET: set MSG_TRUNC if recv buf size is too small */
+	if (sk->sk_type == SOCK_SEQPACKET) {
+		if (copied < rlen)
+			msg->msg_flags |= MSG_TRUNC;
+		/* each iucv message contains a complete record */
+		msg->msg_flags |= MSG_EOR;
+	}
+
+	/* create control message to store iucv msg target class:
+	 * get the trgcls from the control buffer of the skb due to
+	 * fragmentation of original iucv message. */
+	err = put_cmsg(msg, SOL_IUCV, SCM_IUCV_TRGCLS,
+		       sizeof(IUCV_SKB_CB(skb)->class),
+		       (void *)&IUCV_SKB_CB(skb)->class);
+	if (err) {
+		if (!(flags & MSG_PEEK))
+			skb_queue_head(&sk->sk_receive_queue, skb);
+		return err;
+	}
+
+	/* Mark read part of skb as used */
+	if (!(flags & MSG_PEEK)) {
+
+		/* SOCK_STREAM: re-queue skb if it contains unreceived data */
+		if (sk->sk_type == SOCK_STREAM) {
+			if (copied < rlen) {
+				IUCV_SKB_CB(skb)->offset = offset + copied;
+				skb_queue_head(&sk->sk_receive_queue, skb);
+				goto done;
+			}
+		}
+
+		kfree_skb(skb);
+		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
+			atomic_inc(&iucv->msg_recv);
+			if (atomic_read(&iucv->msg_recv) > iucv->msglimit) {
+				WARN_ON(1);
+				iucv_sock_close(sk);
+				return -EFAULT;
+			}
+		}
+
+		/* Queue backlog skbs */
+		spin_lock_bh(&iucv->message_q.lock);
+		rskb = skb_dequeue(&iucv->backlog_skb_q);
+		while (rskb) {
+			IUCV_SKB_CB(rskb)->offset = 0;
+			if (__sock_queue_rcv_skb(sk, rskb)) {
+				/* handle rcv queue full */
+				skb_queue_head(&iucv->backlog_skb_q,
+						rskb);
+				break;
+			}
+			rskb = skb_dequeue(&iucv->backlog_skb_q);
+		}
+		if (skb_queue_empty(&iucv->backlog_skb_q)) {
+			if (!list_empty(&iucv->message_q.list))
+				iucv_process_message_q(sk);
+			if (atomic_read(&iucv->msg_recv) >=
+							iucv->msglimit / 2) {
+				err = iucv_send_ctrl(sk, AF_IUCV_FLAG_WIN);
+				if (err) {
+					sk->sk_state = IUCV_DISCONN;
+					sk->sk_state_change(sk);
+				}
+			}
+		}
+		spin_unlock_bh(&iucv->message_q.lock);
+	}
+
+done:
+	/* SOCK_SEQPACKET: return real length if MSG_TRUNC is set */
+	if (sk->sk_type == SOCK_SEQPACKET && (flags & MSG_TRUNC))
+		copied = rlen;
+
+	return copied;
+}
+
+static inline __poll_t 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 EPOLLIN | EPOLLRDNORM;
+	}
+
+	return 0;
+}
+
+static __poll_t iucv_sock_poll(struct file *file, struct socket *sock,
+			       poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	__poll_t mask = 0;
+
+	sock_poll_wait(file, sock, wait);
+
+	if (sk->sk_state == IUCV_LISTEN)
+		return iucv_accept_poll(sk);
+
+	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
+		mask |= EPOLLERR |
+			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
+
+	if (sk->sk_shutdown & RCV_SHUTDOWN)
+		mask |= EPOLLRDHUP;
+
+	if (sk->sk_shutdown == SHUTDOWN_MASK)
+		mask |= EPOLLHUP;
+
+	if (!skb_queue_empty(&sk->sk_receive_queue) ||
+	    (sk->sk_shutdown & RCV_SHUTDOWN))
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	if (sk->sk_state == IUCV_CLOSED)
+		mask |= EPOLLHUP;
+
+	if (sk->sk_state == IUCV_DISCONN)
+		mask |= EPOLLIN;
+
+	if (sock_writeable(sk) && iucv_below_msglim(sk))
+		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
+	else
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+	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;
+
+	how++;
+
+	if ((how & ~SHUTDOWN_MASK) || !how)
+		return -EINVAL;
+
+	lock_sock(sk);
+	switch (sk->sk_state) {
+	case IUCV_LISTEN:
+	case IUCV_DISCONN:
+	case IUCV_CLOSING:
+	case IUCV_CLOSED:
+		err = -ENOTCONN;
+		goto fail;
+	default:
+		break;
+	}
+
+	if ((how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) &&
+	    sk->sk_state == IUCV_CONNECTED) {
+		if (iucv->transport == AF_IUCV_TRANS_IUCV) {
+			txmsg.class = 0;
+			txmsg.tag = 0;
+			err = pr_iucv->message_send(iucv->path, &txmsg,
+				IUCV_IPRMDATA, 0, (void *) iprm_shutdown, 8);
+			if (err) {
+				switch (err) {
+				case 1:
+					err = -ENOTCONN;
+					break;
+				case 2:
+					err = -ECONNRESET;
+					break;
+				default:
+					err = -ENOTCONN;
+					break;
+				}
+			}
+		} else
+			iucv_send_ctrl(sk, AF_IUCV_FLAG_SHT);
+	}
+
+	sk->sk_shutdown |= how;
+	if (how == RCV_SHUTDOWN || how == SHUTDOWN_MASK) {
+		if ((iucv->transport == AF_IUCV_TRANS_IUCV) &&
+		    iucv->path) {
+			err = pr_iucv->path_quiesce(iucv->path, NULL);
+			if (err)
+				err = -ENOTCONN;
+/*			skb_queue_purge(&sk->sk_receive_queue); */
+		}
+		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);
+
+	sock_orphan(sk);
+	iucv_sock_kill(sk);
+	return err;
+}
+
+/* getsockopt and setsockopt */
+static int iucv_sock_setsockopt(struct socket *sock, int level, int optname,
+				sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct iucv_sock *iucv = iucv_sk(sk);
+	int val;
+	int rc;
+
+	if (level != SOL_IUCV)
+		return -ENOPROTOOPT;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+
+	if (copy_from_sockptr(&val, optval, sizeof(int)))
+		return -EFAULT;
+
+	rc = 0;
+
+	lock_sock(sk);
+	switch (optname) {
+	case SO_IPRMDATA_MSG:
+		if (val)
+			iucv->flags |= IUCV_IPRMDATA;
+		else
+			iucv->flags &= ~IUCV_IPRMDATA;
+		break;
+	case SO_MSGLIMIT:
+		switch (sk->sk_state) {
+		case IUCV_OPEN:
+		case IUCV_BOUND:
+			if (val < 1 || val > U16_MAX)
+				rc = -EINVAL;
+			else
+				iucv->msglimit = val;
+			break;
+		default:
+			rc = -EINVAL;
+			break;
+		}
+		break;
+	default:
+		rc = -ENOPROTOOPT;
+		break;
+	}
+	release_sock(sk);
+
+	return rc;
+}
+
+static int iucv_sock_getsockopt(struct socket *sock, int level, int optname,
+				char __user *optval, int __user *optlen)
+{
+	struct sock *sk = sock->sk;
+	struct iucv_sock *iucv = iucv_sk(sk);
+	unsigned int val;
+	int len;
+
+	if (level != SOL_IUCV)
+		return -ENOPROTOOPT;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+
+	if (len < 0)
+		return -EINVAL;
+
+	len = min_t(unsigned int, len, sizeof(int));
+
+	switch (optname) {
+	case SO_IPRMDATA_MSG:
+		val = (iucv->flags & IUCV_IPRMDATA) ? 1 : 0;
+		break;
+	case SO_MSGLIMIT:
+		lock_sock(sk);
+		val = (iucv->path != NULL) ? iucv->path->msglim	/* connected */
+					   : iucv->msglimit;	/* default */
+		release_sock(sk);
+		break;
+	case SO_MSGSIZE:
+		if (sk->sk_state == IUCV_OPEN)
+			return -EBADFD;
+		val = (iucv->hs_dev) ? iucv->hs_dev->mtu -
+				sizeof(struct af_iucv_trans_hdr) - ETH_HLEN :
+				0x7fffffff;
+		break;
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	if (put_user(len, optlen))
+		return -EFAULT;
+	if (copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+/* 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 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, &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 = pr_iucv->path_sever(path, user_data);
+		iucv_path_free(path);
+		goto fail;
+	}
+
+	/* Check for backlog size */
+	if (sk_acceptq_is_full(sk)) {
+		err = pr_iucv->path_sever(path, user_data);
+		iucv_path_free(path);
+		goto fail;
+	}
+
+	/* Create the new socket */
+	nsk = iucv_sock_alloc(NULL, sk->sk_protocol, GFP_ATOMIC, 0);
+	if (!nsk) {
+		err = pr_iucv->path_sever(path, user_data);
+		iucv_path_free(path);
+		goto fail;
+	}
+
+	niucv = iucv_sk(nsk);
+	iucv_sock_init(nsk, sk);
+	niucv->transport = AF_IUCV_TRANS_IUCV;
+	nsk->sk_allocation |= GFP_DMA;
+
+	/* 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);
+
+	/* set message limit for path based on msglimit of accepting socket */
+	niucv->msglimit = iucv->msglimit;
+	path->msglim = iucv->msglimit;
+	err = pr_iucv->path_accept(path, &af_iucv_handler, nuser_data, nsk);
+	if (err) {
+		iucv_sever_path(nsk, 1);
+		iucv_sock_kill(nsk);
+		goto fail;
+	}
+
+	iucv_accept_enqueue(sk, nsk);
+
+	/* Wake up accept */
+	nsk->sk_state = IUCV_CONNECTED;
+	sk->sk_data_ready(sk);
+	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) {
+		pr_iucv->message_reject(path, msg);
+		return;
+	}
+
+	spin_lock(&iucv->message_q.lock);
+
+	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 += SKB_TRUESIZE(iucv_msg_length(msg));
+	if (len > sk->sk_rcvbuf)
+		goto save_message;
+
+	skb = alloc_iucv_recv_skb(iucv_msg_length(msg));
+	if (!skb)
+		goto save_message;
+
+	iucv_process_message(sk, skb, path, msg);
+	goto out_unlock;
+
+save_message:
+	save_msg = kzalloc(sizeof(struct sock_msg_q), GFP_ATOMIC | GFP_DMA);
+	if (!save_msg)
+		goto out_unlock;
+	save_msg->path = path;
+	save_msg->msg = *msg;
+
+	list_add_tail(&save_msg->list, &iucv->message_q.list);
+
+out_unlock:
+	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 = NULL;
+	struct sk_buff_head *list = &iucv_sk(sk)->send_skb_q;
+	struct sk_buff *list_skb;
+	unsigned long flags;
+
+	bh_lock_sock(sk);
+
+	spin_lock_irqsave(&list->lock, flags);
+	skb_queue_walk(list, list_skb) {
+		if (msg->tag == IUCV_SKB_CB(list_skb)->tag) {
+			this = list_skb;
+			break;
+		}
+	}
+	if (this)
+		__skb_unlink(this, list);
+	spin_unlock_irqrestore(&list->lock, flags);
+
+	if (this) {
+		kfree_skb(this);
+		/* wake up any process waiting for sending */
+		iucv_sock_wake_msglim(sk);
+	}
+
+	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);
+		}
+	}
+	bh_unlock_sock(sk);
+
+}
+
+static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])
+{
+	struct sock *sk = path->private;
+
+	if (sk->sk_state == IUCV_CLOSED)
+		return;
+
+	bh_lock_sock(sk);
+	iucv_sever_path(sk, 1);
+	sk->sk_state = IUCV_DISCONN;
+
+	sk->sk_state_change(sk);
+	bh_unlock_sock(sk);
+}
+
+/* called if the other communication side shuts down its RECV direction;
+ * in turn, the callback sets SEND_SHUTDOWN to disable sending of data.
+ */
+static void iucv_callback_shutdown(struct iucv_path *path, u8 ipuser[16])
+{
+	struct sock *sk = path->private;
+
+	bh_lock_sock(sk);
+	if (sk->sk_state != IUCV_CLOSED) {
+		sk->sk_shutdown |= SEND_SHUTDOWN;
+		sk->sk_state_change(sk);
+	}
+	bh_unlock_sock(sk);
+}
+
+/***************** HiperSockets transport callbacks ********************/
+static void afiucv_swap_src_dest(struct sk_buff *skb)
+{
+	struct af_iucv_trans_hdr *trans_hdr = iucv_trans_hdr(skb);
+	char tmpID[8];
+	char tmpName[8];
+
+	ASCEBC(trans_hdr->destUserID, sizeof(trans_hdr->destUserID));
+	ASCEBC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));
+	ASCEBC(trans_hdr->srcUserID, sizeof(trans_hdr->srcUserID));
+	ASCEBC(trans_hdr->srcAppName, sizeof(trans_hdr->srcAppName));
+	memcpy(tmpID, trans_hdr->srcUserID, 8);
+	memcpy(tmpName, trans_hdr->srcAppName, 8);
+	memcpy(trans_hdr->srcUserID, trans_hdr->destUserID, 8);
+	memcpy(trans_hdr->srcAppName, trans_hdr->destAppName, 8);
+	memcpy(trans_hdr->destUserID, tmpID, 8);
+	memcpy(trans_hdr->destAppName, tmpName, 8);
+	skb_push(skb, ETH_HLEN);
+	memset(skb->data, 0, ETH_HLEN);
+}
+
+/**
+ * afiucv_hs_callback_syn - react on received SYN
+ **/
+static int afiucv_hs_callback_syn(struct sock *sk, struct sk_buff *skb)
+{
+	struct af_iucv_trans_hdr *trans_hdr = iucv_trans_hdr(skb);
+	struct sock *nsk;
+	struct iucv_sock *iucv, *niucv;
+	int err;
+
+	iucv = iucv_sk(sk);
+	if (!iucv) {
+		/* no sock - connection refused */
+		afiucv_swap_src_dest(skb);
+		trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN;
+		err = dev_queue_xmit(skb);
+		goto out;
+	}
+
+	nsk = iucv_sock_alloc(NULL, sk->sk_protocol, GFP_ATOMIC, 0);
+	bh_lock_sock(sk);
+	if ((sk->sk_state != IUCV_LISTEN) ||
+	    sk_acceptq_is_full(sk) ||
+	    !nsk) {
+		/* error on server socket - connection refused */
+		afiucv_swap_src_dest(skb);
+		trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN;
+		err = dev_queue_xmit(skb);
+		iucv_sock_kill(nsk);
+		bh_unlock_sock(sk);
+		goto out;
+	}
+
+	niucv = iucv_sk(nsk);
+	iucv_sock_init(nsk, sk);
+	niucv->transport = AF_IUCV_TRANS_HIPER;
+	niucv->msglimit = iucv->msglimit;
+	if (!trans_hdr->window)
+		niucv->msglimit_peer = IUCV_HIPER_MSGLIM_DEFAULT;
+	else
+		niucv->msglimit_peer = trans_hdr->window;
+	memcpy(niucv->dst_name, trans_hdr->srcAppName, 8);
+	memcpy(niucv->dst_user_id, trans_hdr->srcUserID, 8);
+	memcpy(niucv->src_name, iucv->src_name, 8);
+	memcpy(niucv->src_user_id, iucv->src_user_id, 8);
+	nsk->sk_bound_dev_if = sk->sk_bound_dev_if;
+	niucv->hs_dev = iucv->hs_dev;
+	dev_hold(niucv->hs_dev);
+	afiucv_swap_src_dest(skb);
+	trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_ACK;
+	trans_hdr->window = niucv->msglimit;
+	/* if receiver acks the xmit connection is established */
+	err = dev_queue_xmit(skb);
+	if (!err) {
+		iucv_accept_enqueue(sk, nsk);
+		nsk->sk_state = IUCV_CONNECTED;
+		sk->sk_data_ready(sk);
+	} else
+		iucv_sock_kill(nsk);
+	bh_unlock_sock(sk);
+
+out:
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * afiucv_hs_callback_synack() - react on received SYN-ACK
+ **/
+static int afiucv_hs_callback_synack(struct sock *sk, struct sk_buff *skb)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	if (!iucv)
+		goto out;
+	if (sk->sk_state != IUCV_BOUND)
+		goto out;
+	bh_lock_sock(sk);
+	iucv->msglimit_peer = iucv_trans_hdr(skb)->window;
+	sk->sk_state = IUCV_CONNECTED;
+	sk->sk_state_change(sk);
+	bh_unlock_sock(sk);
+out:
+	kfree_skb(skb);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * afiucv_hs_callback_synfin() - react on received SYN_FIN
+ **/
+static int afiucv_hs_callback_synfin(struct sock *sk, struct sk_buff *skb)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	if (!iucv)
+		goto out;
+	if (sk->sk_state != IUCV_BOUND)
+		goto out;
+	bh_lock_sock(sk);
+	sk->sk_state = IUCV_DISCONN;
+	sk->sk_state_change(sk);
+	bh_unlock_sock(sk);
+out:
+	kfree_skb(skb);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * afiucv_hs_callback_fin() - react on received FIN
+ **/
+static int afiucv_hs_callback_fin(struct sock *sk, struct sk_buff *skb)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	/* other end of connection closed */
+	if (!iucv)
+		goto out;
+	bh_lock_sock(sk);
+	if (sk->sk_state == IUCV_CONNECTED) {
+		sk->sk_state = IUCV_DISCONN;
+		sk->sk_state_change(sk);
+	}
+	bh_unlock_sock(sk);
+out:
+	kfree_skb(skb);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * afiucv_hs_callback_win() - react on received WIN
+ **/
+static int afiucv_hs_callback_win(struct sock *sk, struct sk_buff *skb)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	if (!iucv)
+		return NET_RX_SUCCESS;
+
+	if (sk->sk_state != IUCV_CONNECTED)
+		return NET_RX_SUCCESS;
+
+	atomic_sub(iucv_trans_hdr(skb)->window, &iucv->msg_sent);
+	iucv_sock_wake_msglim(sk);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * afiucv_hs_callback_rx() - react on received data
+ **/
+static int afiucv_hs_callback_rx(struct sock *sk, struct sk_buff *skb)
+{
+	struct iucv_sock *iucv = iucv_sk(sk);
+
+	if (!iucv) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	if (sk->sk_state != IUCV_CONNECTED) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	if (sk->sk_shutdown & RCV_SHUTDOWN) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	/* write stuff from iucv_msg to skb cb */
+	skb_pull(skb, sizeof(struct af_iucv_trans_hdr));
+	skb_reset_transport_header(skb);
+	skb_reset_network_header(skb);
+	IUCV_SKB_CB(skb)->offset = 0;
+	if (sk_filter(sk, skb)) {
+		atomic_inc(&sk->sk_drops);	/* skb rejected by filter */
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	spin_lock(&iucv->message_q.lock);
+	if (skb_queue_empty(&iucv->backlog_skb_q)) {
+		if (__sock_queue_rcv_skb(sk, skb))
+			/* handle rcv queue full */
+			skb_queue_tail(&iucv->backlog_skb_q, skb);
+	} else
+		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
+	spin_unlock(&iucv->message_q.lock);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * afiucv_hs_rcv() - base function for arriving data through HiperSockets
+ *                   transport
+ *                   called from netif RX softirq
+ **/
+static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
+	struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct sock *sk;
+	struct iucv_sock *iucv;
+	struct af_iucv_trans_hdr *trans_hdr;
+	int err = NET_RX_SUCCESS;
+	char nullstring[8];
+
+	if (!pskb_may_pull(skb, sizeof(*trans_hdr))) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	trans_hdr = iucv_trans_hdr(skb);
+	EBCASC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));
+	EBCASC(trans_hdr->destUserID, sizeof(trans_hdr->destUserID));
+	EBCASC(trans_hdr->srcAppName, sizeof(trans_hdr->srcAppName));
+	EBCASC(trans_hdr->srcUserID, sizeof(trans_hdr->srcUserID));
+	memset(nullstring, 0, sizeof(nullstring));
+	iucv = NULL;
+	sk = NULL;
+	read_lock(&iucv_sk_list.lock);
+	sk_for_each(sk, &iucv_sk_list.head) {
+		if (trans_hdr->flags == AF_IUCV_FLAG_SYN) {
+			if ((!memcmp(&iucv_sk(sk)->src_name,
+				     trans_hdr->destAppName, 8)) &&
+			    (!memcmp(&iucv_sk(sk)->src_user_id,
+				     trans_hdr->destUserID, 8)) &&
+			    (!memcmp(&iucv_sk(sk)->dst_name, nullstring, 8)) &&
+			    (!memcmp(&iucv_sk(sk)->dst_user_id,
+				     nullstring, 8))) {
+				iucv = iucv_sk(sk);
+				break;
+			}
+		} else {
+			if ((!memcmp(&iucv_sk(sk)->src_name,
+				     trans_hdr->destAppName, 8)) &&
+			    (!memcmp(&iucv_sk(sk)->src_user_id,
+				     trans_hdr->destUserID, 8)) &&
+			    (!memcmp(&iucv_sk(sk)->dst_name,
+				     trans_hdr->srcAppName, 8)) &&
+			    (!memcmp(&iucv_sk(sk)->dst_user_id,
+				     trans_hdr->srcUserID, 8))) {
+				iucv = iucv_sk(sk);
+				break;
+			}
+		}
+	}
+	read_unlock(&iucv_sk_list.lock);
+	if (!iucv)
+		sk = NULL;
+
+	/* no sock
+	how should we send with no sock
+	1) send without sock no send rc checking?
+	2) introduce default sock to handle this cases
+
+	 SYN -> send SYN|ACK in good case, send SYN|FIN in bad case
+	 data -> send FIN
+	 SYN|ACK, SYN|FIN, FIN -> no action? */
+
+	switch (trans_hdr->flags) {
+	case AF_IUCV_FLAG_SYN:
+		/* connect request */
+		err = afiucv_hs_callback_syn(sk, skb);
+		break;
+	case (AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_ACK):
+		/* connect request confirmed */
+		err = afiucv_hs_callback_synack(sk, skb);
+		break;
+	case (AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN):
+		/* connect request refused */
+		err = afiucv_hs_callback_synfin(sk, skb);
+		break;
+	case (AF_IUCV_FLAG_FIN):
+		/* close request */
+		err = afiucv_hs_callback_fin(sk, skb);
+		break;
+	case (AF_IUCV_FLAG_WIN):
+		err = afiucv_hs_callback_win(sk, skb);
+		if (skb->len == sizeof(struct af_iucv_trans_hdr)) {
+			kfree_skb(skb);
+			break;
+		}
+		fallthrough;	/* and receive non-zero length data */
+	case (AF_IUCV_FLAG_SHT):
+		/* shutdown request */
+		fallthrough;	/* and receive zero length data */
+	case 0:
+		/* plain data frame */
+		IUCV_SKB_CB(skb)->class = trans_hdr->iucv_hdr.class;
+		err = afiucv_hs_callback_rx(sk, skb);
+		break;
+	default:
+		kfree_skb(skb);
+	}
+
+	return err;
+}
+
+/**
+ * afiucv_hs_callback_txnotify() - handle send notifcations from HiperSockets
+ *                                 transport
+ **/
+static void afiucv_hs_callback_txnotify(struct sk_buff *skb,
+					enum iucv_tx_notify n)
+{
+	struct sock *isk = skb->sk;
+	struct sock *sk = NULL;
+	struct iucv_sock *iucv = NULL;
+	struct sk_buff_head *list;
+	struct sk_buff *list_skb;
+	struct sk_buff *nskb;
+	unsigned long flags;
+
+	read_lock_irqsave(&iucv_sk_list.lock, flags);
+	sk_for_each(sk, &iucv_sk_list.head)
+		if (sk == isk) {
+			iucv = iucv_sk(sk);
+			break;
+		}
+	read_unlock_irqrestore(&iucv_sk_list.lock, flags);
+
+	if (!iucv || sock_flag(sk, SOCK_ZAPPED))
+		return;
+
+	list = &iucv->send_skb_q;
+	spin_lock_irqsave(&list->lock, flags);
+	skb_queue_walk_safe(list, list_skb, nskb) {
+		if (skb_shinfo(list_skb) == skb_shinfo(skb)) {
+			switch (n) {
+			case TX_NOTIFY_OK:
+				__skb_unlink(list_skb, list);
+				kfree_skb(list_skb);
+				iucv_sock_wake_msglim(sk);
+				break;
+			case TX_NOTIFY_PENDING:
+				atomic_inc(&iucv->pendings);
+				break;
+			case TX_NOTIFY_DELAYED_OK:
+				__skb_unlink(list_skb, list);
+				atomic_dec(&iucv->pendings);
+				if (atomic_read(&iucv->pendings) <= 0)
+					iucv_sock_wake_msglim(sk);
+				kfree_skb(list_skb);
+				break;
+			case TX_NOTIFY_UNREACHABLE:
+			case TX_NOTIFY_DELAYED_UNREACHABLE:
+			case TX_NOTIFY_TPQFULL: /* not yet used */
+			case TX_NOTIFY_GENERALERROR:
+			case TX_NOTIFY_DELAYED_GENERALERROR:
+				__skb_unlink(list_skb, list);
+				kfree_skb(list_skb);
+				if (sk->sk_state == IUCV_CONNECTED) {
+					sk->sk_state = IUCV_DISCONN;
+					sk->sk_state_change(sk);
+				}
+				break;
+			}
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&list->lock, flags);
+
+	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);
+		}
+	}
+
+}
+
+/*
+ * afiucv_netdev_event: handle netdev notifier chain events
+ */
+static int afiucv_netdev_event(struct notifier_block *this,
+			       unsigned long event, void *ptr)
+{
+	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
+	struct sock *sk;
+	struct iucv_sock *iucv;
+
+	switch (event) {
+	case NETDEV_REBOOT:
+	case NETDEV_GOING_DOWN:
+		sk_for_each(sk, &iucv_sk_list.head) {
+			iucv = iucv_sk(sk);
+			if ((iucv->hs_dev == event_dev) &&
+			    (sk->sk_state == IUCV_CONNECTED)) {
+				if (event == NETDEV_GOING_DOWN)
+					iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN);
+				sk->sk_state = IUCV_DISCONN;
+				sk->sk_state_change(sk);
+			}
+		}
+		break;
+	case NETDEV_DOWN:
+	case NETDEV_UNREGISTER:
+	default:
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block afiucv_netdev_notifier = {
+	.notifier_call = afiucv_netdev_event,
+};
+
+static const 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	= iucv_sock_setsockopt,
+	.getsockopt	= iucv_sock_getsockopt,
+};
+
+static int iucv_sock_create(struct net *net, struct socket *sock, int protocol,
+			    int kern)
+{
+	struct sock *sk;
+
+	if (protocol && protocol != PF_IUCV)
+		return -EPROTONOSUPPORT;
+
+	sock->state = SS_UNCONNECTED;
+
+	switch (sock->type) {
+	case SOCK_STREAM:
+	case SOCK_SEQPACKET:
+		/* currently, proto ops can handle both sk types */
+		sock->ops = &iucv_sock_ops;
+		break;
+	default:
+		return -ESOCKTNOSUPPORT;
+	}
+
+	sk = iucv_sock_alloc(sock, protocol, GFP_KERNEL, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	iucv_sock_init(sk, NULL);
+
+	return 0;
+}
+
+static const struct net_proto_family iucv_sock_family_ops = {
+	.family	= AF_IUCV,
+	.owner	= THIS_MODULE,
+	.create	= iucv_sock_create,
+};
+
+static struct packet_type iucv_packet_type = {
+	.type = cpu_to_be16(ETH_P_AF_IUCV),
+	.func = afiucv_hs_rcv,
+};
+
+static int afiucv_iucv_init(void)
+{
+	return pr_iucv->iucv_register(&af_iucv_handler, 0);
+}
+
+static void afiucv_iucv_exit(void)
+{
+	pr_iucv->iucv_unregister(&af_iucv_handler, 0);
+}
+
+static int __init afiucv_init(void)
+{
+	int err;
+
+	if (MACHINE_IS_VM) {
+		cpcmd("QUERY USERID", iucv_userid, sizeof(iucv_userid), &err);
+		if (unlikely(err)) {
+			WARN_ON(err);
+			err = -EPROTONOSUPPORT;
+			goto out;
+		}
+
+		pr_iucv = try_then_request_module(symbol_get(iucv_if), "iucv");
+		if (!pr_iucv) {
+			printk(KERN_WARNING "iucv_if lookup failed\n");
+			memset(&iucv_userid, 0, sizeof(iucv_userid));
+		}
+	} else {
+		memset(&iucv_userid, 0, sizeof(iucv_userid));
+		pr_iucv = NULL;
+	}
+
+	err = proto_register(&iucv_proto, 0);
+	if (err)
+		goto out;
+	err = sock_register(&iucv_sock_family_ops);
+	if (err)
+		goto out_proto;
+
+	if (pr_iucv) {
+		err = afiucv_iucv_init();
+		if (err)
+			goto out_sock;
+	}
+
+	err = register_netdevice_notifier(&afiucv_netdev_notifier);
+	if (err)
+		goto out_notifier;
+
+	dev_add_pack(&iucv_packet_type);
+	return 0;
+
+out_notifier:
+	if (pr_iucv)
+		afiucv_iucv_exit();
+out_sock:
+	sock_unregister(PF_IUCV);
+out_proto:
+	proto_unregister(&iucv_proto);
+out:
+	if (pr_iucv)
+		symbol_put(iucv_if);
+	return err;
+}
+
+static void __exit afiucv_exit(void)
+{
+	if (pr_iucv) {
+		afiucv_iucv_exit();
+		symbol_put(iucv_if);
+	}
+
+	unregister_netdevice_notifier(&afiucv_netdev_notifier);
+	dev_remove_pack(&iucv_packet_type);
+	sock_unregister(PF_IUCV);
+	proto_unregister(&iucv_proto);
+}
+
+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);