[TIPC] Initial merge

TIPC (Transparent Inter Process Communication) is a protocol designed for
intra cluster communication. For more information see
http://tipc.sourceforge.net

Signed-off-by: Per Liden <per.liden@nospam.ericsson.com>

1 files changed, 1722 insertions, 0 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
new file mode 100644
index 000000000000..22dcb724e760
--- /dev/null
+++ b/net/tipc/socket.c
@@ -0,0 +1,1722 @@
+/*
+ * net/tipc/socket.c: TIPC socket API
+ * 
+ * Copyright (c) 2003-2005, Ericsson Research Canada
+ * Copyright (c) 2004-2005, Wind River Systems
+ * Copyright (c) 2005-2006, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this 
+ * list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright notice, 
+ * this list of conditions and the following disclaimer in the documentation 
+ * and/or other materials provided with the distribution.
+ * Neither the names of the copyright holders nor the names of its 
+ * contributors may be used to endorse or promote products derived from this 
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/version.h>
+#include <linux/fcntl.h>
+#include <linux/version.h>
+#include <asm/semaphore.h>
+#include <asm/string.h>
+#include <asm/atomic.h>
+#include <net/sock.h>
+
+#include <linux/tipc.h>
+#include <net/tipc/tipc_msg.h>
+#include <net/tipc/tipc_port.h>
+
+#include "core.h"
+
+#define SS_LISTENING    -1      /* socket is listening */
+#define SS_READY        -2      /* socket is connectionless */
+
+#define OVERLOAD_LIMIT_BASE    5000
+
+struct tipc_sock {
+        struct sock sk;
+        struct tipc_port *p;
+        struct semaphore sem;
+};
+
+#define tipc_sk(sk) ((struct tipc_sock*)sk)
+
+static u32 dispatch(struct tipc_port *tport, struct sk_buff *buf);
+static void wakeupdispatch(struct tipc_port *tport);
+
+static struct proto_ops packet_ops;
+static struct proto_ops stream_ops;
+static struct proto_ops msg_ops;
+
+static struct proto tipc_proto;
+
+static int sockets_enabled = 0;
+
+static atomic_t tipc_queue_size = ATOMIC_INIT(0);
+
+
+/* 
+ * sock_lock(): Lock a port/socket pair. lock_sock() can 
+ * not be used here, since the same lock must protect ports 
+ * with non-socket interfaces.
+ * See net.c for description of locking policy.
+ */
+static inline void sock_lock(struct tipc_sock* tsock)
+{
+        spin_lock_bh(tsock->p->lock);       
+}
+
+/* 
+ * sock_unlock(): Unlock a port/socket pair
+ */
+static inline void sock_unlock(struct tipc_sock* tsock)
+{
+        spin_unlock_bh(tsock->p->lock);
+}
+
+/**
+ * pollmask - determine the current set of poll() events for a socket
+ * @sock: socket structure
+ * 
+ * TIPC sets the returned events as follows:
+ * a) POLLRDNORM and POLLIN are set if the socket's receive queue is non-empty
+ *    or if a connection-oriented socket is does not have an active connection
+ *    (i.e. a read operation will not block).
+ * b) POLLOUT is set except when a socket's connection has been terminated
+ *    (i.e. a write operation will not block).
+ * c) POLLHUP is set when a socket's connection has been terminated.
+ *
+ * IMPORTANT: The fact that a read or write operation will not block does NOT
+ * imply that the operation will succeed!
+ * 
+ * Returns pollmask value
+ */
+
+static inline u32 pollmask(struct socket *sock)
+{
+        u32 mask;
+
+        if ((skb_queue_len(&sock->sk->sk_receive_queue) != 0) ||
+            (sock->state == SS_UNCONNECTED) ||
+            (sock->state == SS_DISCONNECTING))
+                mask = (POLLRDNORM | POLLIN);
+        else
+                mask = 0;
+
+        if (sock->state == SS_DISCONNECTING) 
+                mask |= POLLHUP;
+        else
+                mask |= POLLOUT;
+
+        return mask;
+}
+
+
+/**
+ * advance_queue - discard first buffer in queue
+ * @tsock: TIPC socket
+ */
+
+static inline void advance_queue(struct tipc_sock *tsock)
+{
+        sock_lock(tsock);
+        buf_discard(skb_dequeue(&tsock->sk.sk_receive_queue));
+        sock_unlock(tsock);
+        atomic_dec(&tipc_queue_size);
+}
+
+/**
+ * tipc_create - create a TIPC socket
+ * @sock: pre-allocated socket structure
+ * @protocol: protocol indicator (must be 0)
+ * 
+ * This routine creates and attaches a 'struct sock' to the 'struct socket',
+ * then create and attaches a TIPC port to the 'struct sock' part.
+ *
+ * Returns 0 on success, errno otherwise
+ */
+static int tipc_create(struct socket *sock, int protocol)
+{
+        struct tipc_sock *tsock;
+        struct tipc_port *port;
+        struct sock *sk;
+        u32 ref;
+
+        if ((sock->type != SOCK_STREAM) && 
+            (sock->type != SOCK_SEQPACKET) &&
+            (sock->type != SOCK_DGRAM) &&
+            (sock->type != SOCK_RDM))
+                return -EPROTOTYPE;
+
+        if (unlikely(protocol != 0))
+                return -EPROTONOSUPPORT;
+
+        ref = tipc_createport_raw(0, &dispatch, &wakeupdispatch, TIPC_LOW_IMPORTANCE);
+        if (unlikely(!ref))
+                return -ENOMEM;
+
+        sock->state = SS_UNCONNECTED;
+
+        switch (sock->type) {
+        case SOCK_STREAM:
+                sock->ops = &stream_ops;
+                break;
+        case SOCK_SEQPACKET:
+                sock->ops = &packet_ops;
+                break;
+        case SOCK_DGRAM:
+                tipc_set_portunreliable(ref, 1);
+                /* fall through */
+        case SOCK_RDM:
+                tipc_set_portunreturnable(ref, 1);
+                sock->ops = &msg_ops;
+                sock->state = SS_READY;
+                break;
+        }
+
+        sk = sk_alloc(AF_TIPC, GFP_KERNEL, &tipc_proto, 1);
+        if (!sk) {
+                tipc_deleteport(ref);
+                return -ENOMEM;
+        }
+
+        sock_init_data(sock, sk);
+        init_waitqueue_head(sk->sk_sleep);
+        sk->sk_rcvtimeo = 8 * HZ;   /* default connect timeout = 8s */
+
+        tsock = tipc_sk(sk);
+        port = tipc_get_port(ref);
+
+        tsock->p = port;
+        port->usr_handle = tsock;
+
+        init_MUTEX(&tsock->sem);
+
+        dbg("sock_create: %x\n",tsock);
+
+        atomic_inc(&tipc_user_count);
+
+        return 0;
+}
+
+/**
+ * release - destroy a TIPC socket
+ * @sock: socket to destroy
+ *
+ * This routine cleans up any messages that are still queued on the socket.
+ * For DGRAM and RDM socket types, all queued messages are rejected.
+ * For SEQPACKET and STREAM socket types, the first message is rejected
+ * and any others are discarded.  (If the first message on a STREAM socket
+ * is partially-read, it is discarded and the next one is rejected instead.)
+ * 
+ * NOTE: Rejected messages are not necessarily returned to the sender!  They
+ * are returned or discarded according to the "destination droppable" setting
+ * specified for the message by the sender.
+ *
+ * Returns 0 on success, errno otherwise
+ */
+
+static int release(struct socket *sock)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sock *sk = sock->sk;
+        int res = TIPC_OK;
+        struct sk_buff *buf;
+
+        dbg("sock_delete: %x\n",tsock);
+        if (!tsock)
+                return 0;
+        down_interruptible(&tsock->sem);
+        if (!sock->sk) {
+                up(&tsock->sem);
+                return 0;
+        }
+        
+        /* Reject unreceived messages, unless no longer connected */
+
+        while (sock->state != SS_DISCONNECTING) {
+                sock_lock(tsock);
+                buf = skb_dequeue(&sk->sk_receive_queue);
+                if (!buf)
+                        tsock->p->usr_handle = 0;
+                sock_unlock(tsock);
+                if (!buf)
+                        break;
+                if (TIPC_SKB_CB(buf)->handle != msg_data(buf_msg(buf)))
+                        buf_discard(buf);
+                else
+                        tipc_reject_msg(buf, TIPC_ERR_NO_PORT);
+                atomic_dec(&tipc_queue_size);
+        }
+
+        /* Delete TIPC port */
+
+        res = tipc_deleteport(tsock->p->ref);
+        sock->sk = NULL;
+
+        /* Discard any remaining messages */
+
+        while ((buf = skb_dequeue(&sk->sk_receive_queue))) {
+                buf_discard(buf);
+                atomic_dec(&tipc_queue_size);
+        }
+
+        up(&tsock->sem);
+
+        sock_put(sk);
+
+        atomic_dec(&tipc_user_count);
+        return res;
+}
+
+/**
+ * bind - associate or disassocate TIPC name(s) with a socket
+ * @sock: socket structure
+ * @uaddr: socket address describing name(s) and desired operation
+ * @uaddr_len: size of socket address data structure
+ * 
+ * Name and name sequence binding is indicated using a positive scope value;
+ * a negative scope value unbinds the specified name.  Specifying no name
+ * (i.e. a socket address length of 0) unbinds all names from the socket.
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int bind(struct socket *sock, struct sockaddr *uaddr, int uaddr_len)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
+        int res;
+
+        if (down_interruptible(&tsock->sem))
+                return -ERESTARTSYS;
+        
+        if (unlikely(!uaddr_len)) {
+                res = tipc_withdraw(tsock->p->ref, 0, 0);
+                goto exit;
+        }
+
+        if (uaddr_len < sizeof(struct sockaddr_tipc)) {
+                res = -EINVAL;
+                goto exit;
+        }
+
+        if (addr->family != AF_TIPC) {
+                res = -EAFNOSUPPORT;
+                goto exit;
+        }
+        if (addr->addrtype == TIPC_ADDR_NAME)
+                addr->addr.nameseq.upper = addr->addr.nameseq.lower;
+        else if (addr->addrtype != TIPC_ADDR_NAMESEQ) {
+                res = -EAFNOSUPPORT;
+                goto exit;
+        }
+        
+        if (addr->scope > 0)
+                res = tipc_publish(tsock->p->ref, addr->scope,
+                                   &addr->addr.nameseq);
+        else
+                res = tipc_withdraw(tsock->p->ref, -addr->scope,
+                                    &addr->addr.nameseq);
+exit:
+        up(&tsock->sem);
+        return res;
+}
+
+/** 
+ * get_name - get port ID of socket or peer socket
+ * @sock: socket structure
+ * @uaddr: area for returned socket address
+ * @uaddr_len: area for returned length of socket address
+ * @peer: 0 to obtain socket name, 1 to obtain peer socket name
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int get_name(struct socket *sock, struct sockaddr *uaddr, 
+                    int *uaddr_len, int peer)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
+        u32 res;
+
+        if (down_interruptible(&tsock->sem))
+                return -ERESTARTSYS;
+
+        *uaddr_len = sizeof(*addr);
+        addr->addrtype = TIPC_ADDR_ID;
+        addr->family = AF_TIPC;
+        addr->scope = 0;
+        if (peer)
+                res = tipc_peer(tsock->p->ref, &addr->addr.id);
+        else
+                res = tipc_ownidentity(tsock->p->ref, &addr->addr.id);
+        addr->addr.name.domain = 0;
+
+        up(&tsock->sem);
+        return res;
+}
+
+/**
+ * poll - read and possibly block on pollmask
+ * @file: file structure associated with the socket
+ * @sock: socket for which to calculate the poll bits
+ * @wait: ???
+ *
+ * Returns the pollmask
+ */
+
+static unsigned int poll(struct file *file, struct socket *sock, 
+                         poll_table *wait)
+{
+        poll_wait(file, sock->sk->sk_sleep, wait);
+        /* NEED LOCK HERE? */
+        return pollmask(sock);
+}
+
+/** 
+ * dest_name_check - verify user is permitted to send to specified port name
+ * @dest: destination address
+ * @m: descriptor for message to be sent
+ * 
+ * Prevents restricted configuration commands from being issued by
+ * unauthorized users.
+ * 
+ * Returns 0 if permission is granted, otherwise errno
+ */
+
+static inline int dest_name_check(struct sockaddr_tipc *dest, struct msghdr *m)
+{
+        struct tipc_cfg_msg_hdr hdr;
+
+        if (likely(dest->addr.name.name.type >= TIPC_RESERVED_TYPES))
+                return 0;
+        if (likely(dest->addr.name.name.type == TIPC_TOP_SRV))
+                return 0;
+
+        if (likely(dest->addr.name.name.type != TIPC_CFG_SRV))
+                return -EACCES;
+
+        if (copy_from_user(&hdr, m->msg_iov[0].iov_base, sizeof(hdr)))
+                return -EFAULT;
+        if ((ntohs(hdr.tcm_type) & 0xC000) & (!capable(CAP_NET_ADMIN)))
+                return -EACCES;
+        
+        return 0;
+}
+
+/**
+ * send_msg - send message in connectionless manner
+ * @iocb: (unused)
+ * @sock: socket structure
+ * @m: message to send
+ * @total_len: (unused)
+ * 
+ * Message must have an destination specified explicitly.
+ * Used for SOCK_RDM and SOCK_DGRAM messages, 
+ * and for 'SYN' messages on SOCK_SEQPACKET and SOCK_STREAM connections.
+ * (Note: 'SYN+' is prohibited on SOCK_STREAM.)
+ * 
+ * Returns the number of bytes sent on success, or errno otherwise
+ */
+
+static int send_msg(struct kiocb *iocb, struct socket *sock,
+                    struct msghdr *m, size_t total_len)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name;
+        struct sk_buff *buf;
+        int needs_conn;
+        int res = -EINVAL;
+
+        if (unlikely(!dest))
+                return -EDESTADDRREQ;
+        if (unlikely(dest->family != AF_TIPC))
+                return -EINVAL;
+
+        needs_conn = (sock->state != SS_READY);
+        if (unlikely(needs_conn)) {
+                if (sock->state == SS_LISTENING)
+                        return -EPIPE;
+                if (sock->state != SS_UNCONNECTED)
+                        return -EISCONN;
+                if ((tsock->p->published) ||
+                    ((sock->type == SOCK_STREAM) && (total_len != 0)))
+                        return -EOPNOTSUPP;
+        }
+
+        if (down_interruptible(&tsock->sem))
+                return -ERESTARTSYS;
+
+        if (needs_conn) {
+
+                /* Abort any pending connection attempts (very unlikely) */
+
+                while ((buf = skb_dequeue(&sock->sk->sk_receive_queue))) {
+                        tipc_reject_msg(buf, TIPC_ERR_NO_PORT);
+                        atomic_dec(&tipc_queue_size);
+                }
+
+                sock->state = SS_CONNECTING;
+        }
+
+        do {
+                if (dest->addrtype == TIPC_ADDR_NAME) {
+                        if ((res = dest_name_check(dest, m)))
+                                goto exit;
+                        res = tipc_send2name(tsock->p->ref,
+                                             &dest->addr.name.name,
+                                             dest->addr.name.domain, 
+                                             m->msg_iovlen,
+                                             m->msg_iov);
+                }
+                else if (dest->addrtype == TIPC_ADDR_ID) {
+                        res = tipc_send2port(tsock->p->ref,
+                                             &dest->addr.id,
+                                             m->msg_iovlen,
+                                             m->msg_iov);
+                }
+                else if (dest->addrtype == TIPC_ADDR_MCAST) {
+                        if (needs_conn) {
+                                res = -EOPNOTSUPP;
+                                goto exit;
+                        }
+                        if ((res = dest_name_check(dest, m)))
+                                goto exit;
+                        res = tipc_multicast(tsock->p->ref,
+                                             &dest->addr.nameseq,
+                                             0,
+                                             m->msg_iovlen,
+                                             m->msg_iov);
+                }
+                if (likely(res != -ELINKCONG)) {
+exit:                                
+                        up(&tsock->sem);
+                        return res;
+                }
+                if (m->msg_flags & MSG_DONTWAIT) {
+                        res = -EWOULDBLOCK;
+                        goto exit;
+                }
+                if (wait_event_interruptible(*sock->sk->sk_sleep,
+                                             !tsock->p->congested)) {
+                    res = -ERESTARTSYS;
+                    goto exit;
+                }
+        } while (1);
+}
+
+/** 
+ * send_packet - send a connection-oriented message
+ * @iocb: (unused)
+ * @sock: socket structure
+ * @m: message to send
+ * @total_len: (unused)
+ * 
+ * Used for SOCK_SEQPACKET messages and SOCK_STREAM data.
+ * 
+ * Returns the number of bytes sent on success, or errno otherwise
+ */
+
+static int send_packet(struct kiocb *iocb, struct socket *sock,
+                       struct msghdr *m, size_t total_len)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name;
+        int res;
+
+        /* Handle implied connection establishment */
+
+        if (unlikely(dest))
+                return send_msg(iocb, sock, m, total_len);
+
+        if (down_interruptible(&tsock->sem)) {
+                return -ERESTARTSYS;
+        }
+
+        if (unlikely(sock->state != SS_CONNECTED)) {
+                if (sock->state == SS_DISCONNECTING)
+                        res = -EPIPE;   
+                else
+                        res = -ENOTCONN;
+                goto exit;
+        }
+
+        do {
+                res = tipc_send(tsock->p->ref, m->msg_iovlen, m->msg_iov);
+                if (likely(res != -ELINKCONG)) {
+exit:
+                        up(&tsock->sem);
+                        return res;
+                }
+                if (m->msg_flags & MSG_DONTWAIT) {
+                        res = -EWOULDBLOCK;
+                        goto exit;
+                }
+                if (wait_event_interruptible(*sock->sk->sk_sleep,
+                                             !tsock->p->congested)) {
+                    res = -ERESTARTSYS;
+                    goto exit;
+                }
+        } while (1);
+}
+
+/** 
+ * send_stream - send stream-oriented data
+ * @iocb: (unused)
+ * @sock: socket structure
+ * @m: data to send
+ * @total_len: total length of data to be sent
+ * 
+ * Used for SOCK_STREAM data.
+ * 
+ * Returns the number of bytes sent on success, or errno otherwise
+ */
+
+
+static int send_stream(struct kiocb *iocb, struct socket *sock,
+                       struct msghdr *m, size_t total_len)
+{
+        struct msghdr my_msg;
+        struct iovec my_iov;
+        struct iovec *curr_iov;
+        int curr_iovlen;
+        char __user *curr_start;
+        int curr_left;
+        int bytes_to_send;
+        int res;
+        
+        if (likely(total_len <= TIPC_MAX_USER_MSG_SIZE))
+                return send_packet(iocb, sock, m, total_len);
+
+        /* Can only send large data streams if already connected */
+
+        if (unlikely(sock->state != SS_CONNECTED)) {
+                if (sock->state == SS_DISCONNECTING)
+                        return -EPIPE;   
+                else
+                        return -ENOTCONN;
+        }
+
+        /* 
+         * Send each iovec entry using one or more messages
+         *
+         * Note: This algorithm is good for the most likely case 
+         * (i.e. one large iovec entry), but could be improved to pass sets
+         * of small iovec entries into send_packet().
+         */
+
+        my_msg = *m;
+        curr_iov = my_msg.msg_iov;
+        curr_iovlen = my_msg.msg_iovlen;
+        my_msg.msg_iov = &my_iov;
+        my_msg.msg_iovlen = 1;
+
+        while (curr_iovlen--) {
+                curr_start = curr_iov->iov_base;
+                curr_left = curr_iov->iov_len;
+
+                while (curr_left) {
+                        bytes_to_send = (curr_left < TIPC_MAX_USER_MSG_SIZE)
+                                ? curr_left : TIPC_MAX_USER_MSG_SIZE;
+                        my_iov.iov_base = curr_start;
+                        my_iov.iov_len = bytes_to_send;
+                        if ((res = send_packet(iocb, sock, &my_msg, 0)) < 0)
+                                return res;
+                        curr_left -= bytes_to_send;
+                        curr_start += bytes_to_send;
+                }
+
+                curr_iov++;
+        }
+
+        return total_len;
+}
+
+/**
+ * auto_connect - complete connection setup to a remote port
+ * @sock: socket structure
+ * @tsock: TIPC-specific socket structure
+ * @msg: peer's response message
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int auto_connect(struct socket *sock, struct tipc_sock *tsock, 
+                        struct tipc_msg *msg)
+{
+        struct tipc_portid peer;
+
+        if (msg_errcode(msg)) {
+                sock->state = SS_DISCONNECTING;
+                return -ECONNREFUSED;
+        }
+
+        peer.ref = msg_origport(msg);
+        peer.node = msg_orignode(msg);
+        tipc_connect2port(tsock->p->ref, &peer);
+        tipc_set_portimportance(tsock->p->ref, msg_importance(msg));
+        sock->state = SS_CONNECTED;
+        return 0;
+}
+
+/**
+ * set_orig_addr - capture sender's address for received message
+ * @m: descriptor for message info
+ * @msg: received message header
+ * 
+ * Note: Address is not captured if not requested by receiver.
+ */
+
+static inline void set_orig_addr(struct msghdr *m, struct tipc_msg *msg)
+{
+        struct sockaddr_tipc *addr = (struct sockaddr_tipc *)m->msg_name;
+
+        if (addr) {
+                addr->family = AF_TIPC;
+                addr->addrtype = TIPC_ADDR_ID;
+                addr->addr.id.ref = msg_origport(msg);
+                addr->addr.id.node = msg_orignode(msg);
+                addr->addr.name.domain = 0;     /* could leave uninitialized */
+                addr->scope = 0;                /* could leave uninitialized */
+                m->msg_namelen = sizeof(struct sockaddr_tipc);
+        }
+}
+
+/**
+ * anc_data_recv - optionally capture ancillary data for received message 
+ * @m: descriptor for message info
+ * @msg: received message header
+ * @tport: TIPC port associated with message
+ * 
+ * Note: Ancillary data is not captured if not requested by receiver.
+ * 
+ * Returns 0 if successful, otherwise errno
+ */
+
+static inline int anc_data_recv(struct msghdr *m, struct tipc_msg *msg, 
+                                struct tipc_port *tport)
+{
+        u32 anc_data[3];
+        u32 err;
+        u32 dest_type;
+        int res;
+
+        if (likely(m->msg_controllen == 0))
+                return 0;
+
+        /* Optionally capture errored message object(s) */
+
+        err = msg ? msg_errcode(msg) : 0;
+        if (unlikely(err)) {
+                anc_data[0] = err;
+                anc_data[1] = msg_data_sz(msg);
+                if ((res = put_cmsg(m, SOL_SOCKET, TIPC_ERRINFO, 8, anc_data)))
+                        return res;
+                if (anc_data[1] &&
+                    (res = put_cmsg(m, SOL_SOCKET, TIPC_RETDATA, anc_data[1], 
+                                    msg_data(msg))))
+                        return res;
+        }
+
+        /* Optionally capture message destination object */
+
+        dest_type = msg ? msg_type(msg) : TIPC_DIRECT_MSG;
+        switch (dest_type) {
+        case TIPC_NAMED_MSG:
+                anc_data[0] = msg_nametype(msg);
+                anc_data[1] = msg_namelower(msg);
+                anc_data[2] = msg_namelower(msg);
+                break;
+        case TIPC_MCAST_MSG:
+                anc_data[0] = msg_nametype(msg);
+                anc_data[1] = msg_namelower(msg);
+                anc_data[2] = msg_nameupper(msg);
+                break;
+        case TIPC_CONN_MSG:
+                anc_data[0] = tport->conn_type;
+                anc_data[1] = tport->conn_instance;
+                anc_data[2] = tport->conn_instance;
+                break;
+        default:
+                anc_data[0] = 0;
+        }
+        if (anc_data[0] &&
+            (res = put_cmsg(m, SOL_SOCKET, TIPC_DESTNAME, 12, anc_data)))
+                return res;
+
+        return 0;
+}
+
+/** 
+ * recv_msg - receive packet-oriented message
+ * @iocb: (unused)
+ * @m: descriptor for message info
+ * @buf_len: total size of user buffer area
+ * @flags: receive flags
+ * 
+ * Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages.
+ * If the complete message doesn't fit in user area, truncate it.
+ *
+ * Returns size of returned message data, errno otherwise
+ */
+
+static int recv_msg(struct kiocb *iocb, struct socket *sock,
+                    struct msghdr *m, size_t buf_len, int flags)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sk_buff *buf;
+        struct tipc_msg *msg;
+        unsigned int q_len;
+        unsigned int sz;
+        u32 err;
+        int res;
+
+        /* Currently doesn't support receiving into multiple iovec entries */
+
+        if (m->msg_iovlen != 1)
+                return -EOPNOTSUPP;
+
+        /* Catch invalid receive attempts */
+
+        if (unlikely(!buf_len))
+                return -EINVAL;
+
+        if (sock->type == SOCK_SEQPACKET) {
+                if (unlikely(sock->state == SS_UNCONNECTED))
+                        return -ENOTCONN;
+                if (unlikely((sock->state == SS_DISCONNECTING) && 
+                             (skb_queue_len(&sock->sk->sk_receive_queue) == 0)))
+                        return -ENOTCONN;
+        }
+
+        /* Look for a message in receive queue; wait if necessary */
+
+        if (unlikely(down_interruptible(&tsock->sem)))
+                return -ERESTARTSYS;
+
+restart:
+        if (unlikely((skb_queue_len(&sock->sk->sk_receive_queue) == 0) &&
+                     (flags & MSG_DONTWAIT))) {
+                res = -EWOULDBLOCK;
+                goto exit;
+        }
+
+        if ((res = wait_event_interruptible(
+                *sock->sk->sk_sleep, 
+                ((q_len = skb_queue_len(&sock->sk->sk_receive_queue)) ||
+                 (sock->state == SS_DISCONNECTING))) )) {
+                goto exit;
+        }
+
+        /* Catch attempt to receive on an already terminated connection */
+        /* [THIS CHECK MAY OVERLAP WITH AN EARLIER CHECK] */
+
+        if (!q_len) {
+                res = -ENOTCONN;
+                goto exit;
+        }
+
+        /* Get access to first message in receive queue */
+
+        buf = skb_peek(&sock->sk->sk_receive_queue);
+        msg = buf_msg(buf);
+        sz = msg_data_sz(msg);
+        err = msg_errcode(msg);
+
+        /* Complete connection setup for an implied connect */
+
+        if (unlikely(sock->state == SS_CONNECTING)) {
+                if ((res = auto_connect(sock, tsock, msg)))
+                        goto exit;
+        }
+
+        /* Discard an empty non-errored message & try again */
+
+        if ((!sz) && (!err)) {
+                advance_queue(tsock);
+                goto restart;
+        }
+
+        /* Capture sender's address (optional) */
+
+        set_orig_addr(m, msg);
+
+        /* Capture ancillary data (optional) */
+
+        if ((res = anc_data_recv(m, msg, tsock->p)))
+                goto exit;
+
+        /* Capture message data (if valid) & compute return value (always) */
+        
+        if (!err) {
+                if (unlikely(buf_len < sz)) {
+                        sz = buf_len;
+                        m->msg_flags |= MSG_TRUNC;
+                }
+                if (unlikely(copy_to_user(m->msg_iov->iov_base, msg_data(msg),
+                                          sz))) {
+                        res = -EFAULT;
+                        goto exit;
+                }
+                res = sz;
+        } else {
+                if ((sock->state == SS_READY) ||
+                    ((err == TIPC_CONN_SHUTDOWN) || m->msg_control))
+                        res = 0;
+                else
+                        res = -ECONNRESET;
+        }
+
+        /* Consume received message (optional) */
+
+        if (likely(!(flags & MSG_PEEK))) {
+                if (unlikely(++tsock->p->conn_unacked >= TIPC_FLOW_CONTROL_WIN))
+                        tipc_acknowledge(tsock->p->ref, tsock->p->conn_unacked);
+                advance_queue(tsock);
+        }
+exit:
+        up(&tsock->sem);
+        return res;
+}
+
+/** 
+ * recv_stream - receive stream-oriented data
+ * @iocb: (unused)
+ * @m: descriptor for message info
+ * @buf_len: total size of user buffer area
+ * @flags: receive flags
+ * 
+ * Used for SOCK_STREAM messages only.  If not enough data is available 
+ * will optionally wait for more; never truncates data.
+ *
+ * Returns size of returned message data, errno otherwise
+ */
+
+static int recv_stream(struct kiocb *iocb, struct socket *sock,
+                       struct msghdr *m, size_t buf_len, int flags)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sk_buff *buf;
+        struct tipc_msg *msg;
+        unsigned int q_len;
+        unsigned int sz;
+        int sz_to_copy;
+        int sz_copied = 0;
+        int needed;
+        char *crs = m->msg_iov->iov_base;
+        unsigned char *buf_crs;
+        u32 err;
+        int res;
+
+        /* Currently doesn't support receiving into multiple iovec entries */
+
+        if (m->msg_iovlen != 1)
+                return -EOPNOTSUPP;
+
+        /* Catch invalid receive attempts */
+
+        if (unlikely(!buf_len))
+                return -EINVAL;
+
+        if (unlikely(sock->state == SS_DISCONNECTING)) {
+                if (skb_queue_len(&sock->sk->sk_receive_queue) == 0)
+                        return -ENOTCONN;
+        } else if (unlikely(sock->state != SS_CONNECTED))
+                return -ENOTCONN;
+
+        /* Look for a message in receive queue; wait if necessary */
+
+        if (unlikely(down_interruptible(&tsock->sem)))
+                return -ERESTARTSYS;
+
+restart:
+        if (unlikely((skb_queue_len(&sock->sk->sk_receive_queue) == 0) &&
+                     (flags & MSG_DONTWAIT))) {
+                res = (sz_copied == 0) ? -EWOULDBLOCK : 0;
+                goto exit;
+        }
+
+        if ((res = wait_event_interruptible(
+                *sock->sk->sk_sleep, 
+                ((q_len = skb_queue_len(&sock->sk->sk_receive_queue)) ||
+                 (sock->state == SS_DISCONNECTING))) )) {
+                goto exit;
+        }
+
+        /* Catch attempt to receive on an already terminated connection */
+        /* [THIS CHECK MAY OVERLAP WITH AN EARLIER CHECK] */
+
+        if (!q_len) {
+                res = -ENOTCONN;
+                goto exit;
+        }
+
+        /* Get access to first message in receive queue */
+
+        buf = skb_peek(&sock->sk->sk_receive_queue);
+        msg = buf_msg(buf);
+        sz = msg_data_sz(msg);
+        err = msg_errcode(msg);
+
+        /* Discard an empty non-errored message & try again */
+
+        if ((!sz) && (!err)) {
+                advance_queue(tsock);
+                goto restart;
+        }
+
+        /* Optionally capture sender's address & ancillary data of first msg */
+
+        if (sz_copied == 0) {
+                set_orig_addr(m, msg);
+                if ((res = anc_data_recv(m, msg, tsock->p)))
+                        goto exit;
+        }
+
+        /* Capture message data (if valid) & compute return value (always) */
+        
+        if (!err) {
+                buf_crs = (unsigned char *)(TIPC_SKB_CB(buf)->handle);
+                sz = buf->tail - buf_crs;
+
+                needed = (buf_len - sz_copied);
+                sz_to_copy = (sz <= needed) ? sz : needed;
+                if (unlikely(copy_to_user(crs, buf_crs, sz_to_copy))) {
+                        res = -EFAULT;
+                        goto exit;
+                }
+                sz_copied += sz_to_copy;
+
+                if (sz_to_copy < sz) {
+                        if (!(flags & MSG_PEEK))
+                                TIPC_SKB_CB(buf)->handle = buf_crs + sz_to_copy;
+                        goto exit;
+                }
+
+                crs += sz_to_copy;
+        } else {
+                if (sz_copied != 0)
+                        goto exit; /* can't add error msg to valid data */
+
+                if ((err == TIPC_CONN_SHUTDOWN) || m->msg_control)
+                        res = 0;
+                else
+                        res = -ECONNRESET;
+        }
+
+        /* Consume received message (optional) */
+
+        if (likely(!(flags & MSG_PEEK))) {
+                if (unlikely(++tsock->p->conn_unacked >= TIPC_FLOW_CONTROL_WIN))
+                        tipc_acknowledge(tsock->p->ref, tsock->p->conn_unacked);
+                advance_queue(tsock);
+        }
+
+        /* Loop around if more data is required */
+
+        if ((sz_copied < buf_len)    /* didn't get all requested data */ 
+            && (flags & MSG_WAITALL) /* ... and need to wait for more */
+            && (!(flags & MSG_PEEK)) /* ... and aren't just peeking at data */
+            && (!err)                /* ... and haven't reached a FIN */
+            )
+                goto restart;
+
+exit:
+        up(&tsock->sem);
+        return res ? res : sz_copied;
+}
+
+/**
+ * queue_overloaded - test if queue overload condition exists
+ * @queue_size: current size of queue
+ * @base: nominal maximum size of queue
+ * @msg: message to be added to queue
+ * 
+ * Returns 1 if queue is currently overloaded, 0 otherwise
+ */
+
+static int queue_overloaded(u32 queue_size, u32 base, struct tipc_msg *msg)
+{
+        u32 threshold;
+        u32 imp = msg_importance(msg);
+
+        if (imp == TIPC_LOW_IMPORTANCE)
+                threshold = base;
+        else if (imp == TIPC_MEDIUM_IMPORTANCE)
+                threshold = base * 2;
+        else if (imp == TIPC_HIGH_IMPORTANCE)
+                threshold = base * 100;
+        else
+                return 0;
+
+        if (msg_connected(msg))
+                threshold *= 4;
+
+        return (queue_size > threshold);
+}
+
+/** 
+ * async_disconnect - wrapper function used to disconnect port
+ * @portref: TIPC port reference (passed as pointer-sized value)
+ */
+
+static void async_disconnect(unsigned long portref)
+{
+        tipc_disconnect((u32)portref);
+}
+
+/** 
+ * dispatch - handle arriving message
+ * @tport: TIPC port that received message
+ * @buf: message
+ * 
+ * Called with port locked.  Must not take socket lock to avoid deadlock risk.
+ * 
+ * Returns TIPC error status code (TIPC_OK if message is not to be rejected)
+ */
+
+static u32 dispatch(struct tipc_port *tport, struct sk_buff *buf)
+{
+        struct tipc_msg *msg = buf_msg(buf);
+        struct tipc_sock *tsock = (struct tipc_sock *)tport->usr_handle;
+        struct socket *sock;
+        u32 recv_q_len;
+
+        /* Reject message if socket is closing */
+
+        if (!tsock)
+                return TIPC_ERR_NO_PORT;
+
+        /* Reject message if it is wrong sort of message for socket */
+
+        /*
+         * WOULD IT BE BETTER TO JUST DISCARD THESE MESSAGES INSTEAD?
+         * "NO PORT" ISN'T REALLY THE RIGHT ERROR CODE, AND THERE MAY
+         * BE SECURITY IMPLICATIONS INHERENT IN REJECTING INVALID TRAFFIC
+         */
+        sock = tsock->sk.sk_socket;
+        if (sock->state == SS_READY) {
+                if (msg_connected(msg)) {
+                        msg_dbg(msg, "dispatch filter 1\n");
+                        return TIPC_ERR_NO_PORT;
+                }
+        } else {
+                if (msg_mcast(msg)) {
+                        msg_dbg(msg, "dispatch filter 2\n");
+                        return TIPC_ERR_NO_PORT;
+                }
+                if (sock->state == SS_CONNECTED) {
+                        if (!msg_connected(msg)) {
+                                msg_dbg(msg, "dispatch filter 3\n");
+                                return TIPC_ERR_NO_PORT;
+                        }
+                }
+                else if (sock->state == SS_CONNECTING) {
+                        if (!msg_connected(msg) && (msg_errcode(msg) == 0)) {
+                                msg_dbg(msg, "dispatch filter 4\n");
+                                return TIPC_ERR_NO_PORT;
+                        }
+                } 
+                else if (sock->state == SS_LISTENING) {
+                        if (msg_connected(msg) || msg_errcode(msg)) {
+                                msg_dbg(msg, "dispatch filter 5\n");
+                                return TIPC_ERR_NO_PORT;
+                        }
+                } 
+                else if (sock->state == SS_DISCONNECTING) {
+                        msg_dbg(msg, "dispatch filter 6\n");
+                        return TIPC_ERR_NO_PORT;
+                }
+                else /* (sock->state == SS_UNCONNECTED) */ {
+                        if (msg_connected(msg) || msg_errcode(msg)) {
+                                msg_dbg(msg, "dispatch filter 7\n");
+                                return TIPC_ERR_NO_PORT;
+                        }
+                }
+        }
+
+        /* Reject message if there isn't room to queue it */
+
+        if (unlikely((u32)atomic_read(&tipc_queue_size) > 
+                     OVERLOAD_LIMIT_BASE)) {
+                if (queue_overloaded(atomic_read(&tipc_queue_size), 
+                                     OVERLOAD_LIMIT_BASE, msg))
+                        return TIPC_ERR_OVERLOAD;
+        }
+        recv_q_len = skb_queue_len(&tsock->sk.sk_receive_queue);
+        if (unlikely(recv_q_len > (OVERLOAD_LIMIT_BASE / 2))) {
+                if (queue_overloaded(recv_q_len, 
+                                     OVERLOAD_LIMIT_BASE / 2, msg)) 
+                        return TIPC_ERR_OVERLOAD;
+        }
+
+        /* Initiate connection termination for an incoming 'FIN' */
+
+        if (unlikely(msg_errcode(msg) && (sock->state == SS_CONNECTED))) {
+                sock->state = SS_DISCONNECTING;
+                /* Note: Use signal since port lock is already taken! */
+                k_signal((Handler)async_disconnect, tport->ref);
+        }
+
+        /* Enqueue message (finally!) */
+
+        msg_dbg(msg,"<DISP<: ");
+        TIPC_SKB_CB(buf)->handle = msg_data(msg);
+        atomic_inc(&tipc_queue_size);
+        skb_queue_tail(&sock->sk->sk_receive_queue, buf);
+
+        wake_up_interruptible(sock->sk->sk_sleep);
+        return TIPC_OK;
+}
+
+/** 
+ * wakeupdispatch - wake up port after congestion
+ * @tport: port to wakeup
+ * 
+ * Called with port lock on.
+ */
+
+static void wakeupdispatch(struct tipc_port *tport)
+{
+        struct tipc_sock *tsock = (struct tipc_sock *)tport->usr_handle;
+
+        wake_up_interruptible(tsock->sk.sk_sleep);
+}
+
+/**
+ * connect - establish a connection to another TIPC port
+ * @sock: socket structure
+ * @dest: socket address for destination port
+ * @destlen: size of socket address data structure
+ * @flags: (unused)
+ *
+ * Returns 0 on success, errno otherwise
+ */
+
+static int connect(struct socket *sock, struct sockaddr *dest, int destlen, 
+                   int flags)
+{
+   struct tipc_sock *tsock = tipc_sk(sock->sk);
+   struct sockaddr_tipc *dst = (struct sockaddr_tipc *)dest;
+   struct msghdr m = {0,};
+   struct sk_buff *buf;
+   struct tipc_msg *msg;
+   int res;
+
+   /* For now, TIPC does not allow use of connect() with DGRAM or RDM types */
+
+   if (sock->state == SS_READY)
+           return -EOPNOTSUPP;
+
+   /* MOVE THE REST OF THIS ERROR CHECKING TO send_msg()? */
+   if (sock->state == SS_LISTENING)
+           return -EOPNOTSUPP;
+   if (sock->state == SS_CONNECTING)
+           return -EALREADY;
+   if (sock->state != SS_UNCONNECTED)
+           return -EISCONN;
+
+   if ((dst->family != AF_TIPC) ||
+       ((dst->addrtype != TIPC_ADDR_NAME) && (dst->addrtype != TIPC_ADDR_ID)))
+           return -EINVAL;
+
+   /* Send a 'SYN-' to destination */
+
+   m.msg_name = dest;
+   if ((res = send_msg(0, sock, &m, 0)) < 0) {
+           sock->state = SS_DISCONNECTING;
+           return res;
+   }
+
+   if (down_interruptible(&tsock->sem)) 
+           return -ERESTARTSYS;
+        
+   /* Wait for destination's 'ACK' response */
+
+   res = wait_event_interruptible_timeout(*sock->sk->sk_sleep,
+                                          skb_queue_len(&sock->sk->sk_receive_queue),
+                                          sock->sk->sk_rcvtimeo);
+   buf = skb_peek(&sock->sk->sk_receive_queue);
+   if (res > 0) {
+           msg = buf_msg(buf);
+           res = auto_connect(sock, tsock, msg);
+           if (!res) {
+                   if (dst->addrtype == TIPC_ADDR_NAME) {
+                           tsock->p->conn_type = dst->addr.name.name.type;
+                           tsock->p->conn_instance = dst->addr.name.name.instance;
+                   }
+                   if (!msg_data_sz(msg))
+                           advance_queue(tsock);
+           }
+   } else {
+           if (res == 0) {
+                   res = -ETIMEDOUT;
+           } else
+                   { /* leave "res" unchanged */ }
+           sock->state = SS_DISCONNECTING;
+   }
+
+   up(&tsock->sem);
+   return res;
+}
+
+/** 
+ * listen - allow socket to listen for incoming connections
+ * @sock: socket structure
+ * @len: (unused)
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int listen(struct socket *sock, int len)
+{
+        /* REQUIRES SOCKET LOCKING OF SOME SORT? */
+
+        if (sock->state == SS_READY)
+                return -EOPNOTSUPP;
+        if (sock->state != SS_UNCONNECTED)
+                return -EINVAL;
+        sock->state = SS_LISTENING;
+        return 0;
+}
+
+/** 
+ * accept - wait for connection request
+ * @sock: listening socket
+ * @newsock: new socket that is to be connected
+ * @flags: file-related flags associated with socket
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int accept(struct socket *sock, struct socket *newsock, int flags)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        struct sk_buff *buf;
+        int res = -EFAULT;
+
+        if (sock->state == SS_READY)
+                return -EOPNOTSUPP;
+        if (sock->state != SS_LISTENING)
+                return -EINVAL;
+        
+        if (unlikely((skb_queue_len(&sock->sk->sk_receive_queue) == 0) && 
+                     (flags & O_NONBLOCK)))
+                return -EWOULDBLOCK;
+
+        if (down_interruptible(&tsock->sem))
+                return -ERESTARTSYS;
+
+        if (wait_event_interruptible(*sock->sk->sk_sleep, 
+                                     skb_queue_len(&sock->sk->sk_receive_queue))) {
+                res = -ERESTARTSYS;
+                goto exit;
+        }
+        buf = skb_peek(&sock->sk->sk_receive_queue);
+
+        res = tipc_create(newsock, 0);
+        if (!res) {
+                struct tipc_sock *new_tsock = tipc_sk(newsock->sk);
+                struct tipc_portid id;
+                struct tipc_msg *msg = buf_msg(buf);
+                u32 new_ref = new_tsock->p->ref;
+
+                id.ref = msg_origport(msg);
+                id.node = msg_orignode(msg);
+                tipc_connect2port(new_ref, &id);
+                newsock->state = SS_CONNECTED;
+
+                tipc_set_portimportance(new_ref, msg_importance(msg));
+                if (msg_named(msg)) {
+                        new_tsock->p->conn_type = msg_nametype(msg);
+                        new_tsock->p->conn_instance = msg_nameinst(msg);
+                }
+
+               /* 
+                 * Respond to 'SYN-' by discarding it & returning 'ACK'-.
+                 * Respond to 'SYN+' by queuing it on new socket.
+                 */
+
+                msg_dbg(msg,"<ACC<: ");
+                if (!msg_data_sz(msg)) {
+                        struct msghdr m = {0,};
+
+                        send_packet(0, newsock, &m, 0);      
+                        advance_queue(tsock);
+                } else {
+                        sock_lock(tsock);
+                        skb_dequeue(&sock->sk->sk_receive_queue);
+                        sock_unlock(tsock);
+                        skb_queue_head(&newsock->sk->sk_receive_queue, buf);
+                }
+        }
+exit:
+        up(&tsock->sem);
+        return res;
+}
+
+/**
+ * shutdown - shutdown socket connection
+ * @sock: socket structure
+ * @how: direction to close (always treated as read + write)
+ *
+ * Terminates connection (if necessary), then purges socket's receive queue.
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int shutdown(struct socket *sock, int how)
+{
+        struct tipc_sock* tsock = tipc_sk(sock->sk);
+        struct sk_buff *buf;
+        int res;
+
+        /* Could return -EINVAL for an invalid "how", but why bother? */
+
+        if (down_interruptible(&tsock->sem))
+                return -ERESTARTSYS;
+
+        sock_lock(tsock);
+
+        switch (sock->state) {
+        case SS_CONNECTED:
+
+                /* Send 'FIN+' or 'FIN-' message to peer */
+
+                sock_unlock(tsock);
+restart:
+                if ((buf = skb_dequeue(&sock->sk->sk_receive_queue))) {
+                        atomic_dec(&tipc_queue_size);
+                        if (TIPC_SKB_CB(buf)->handle != msg_data(buf_msg(buf))) {
+                                buf_discard(buf);
+                                goto restart;
+                        }
+                        tipc_reject_msg(buf, TIPC_CONN_SHUTDOWN);
+                }
+                else {
+                        tipc_shutdown(tsock->p->ref);
+                }
+                sock_lock(tsock);
+
+                /* fall through */
+
+        case SS_DISCONNECTING:
+
+                /* Discard any unreceived messages */
+
+                while ((buf = skb_dequeue(&sock->sk->sk_receive_queue))) {
+                        atomic_dec(&tipc_queue_size);
+                        buf_discard(buf);
+                }
+                tsock->p->conn_unacked = 0;
+
+                /* fall through */
+
+        case SS_CONNECTING:
+                sock->state = SS_DISCONNECTING;
+                res = 0;
+                break;
+
+        default:
+                res = -ENOTCONN;
+        }
+
+        sock_unlock(tsock);
+
+        up(&tsock->sem);
+        return res;
+}
+
+/**
+ * setsockopt - set socket option
+ * @sock: socket structure
+ * @lvl: option level
+ * @opt: option identifier
+ * @ov: pointer to new option value
+ * @ol: length of option value
+ * 
+ * For stream sockets only, accepts and ignores all IPPROTO_TCP options 
+ * (to ease compatibility).
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int setsockopt(struct socket *sock, int lvl, int opt, char *ov, int ol)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        u32 value;
+        int res;
+
+        if ((lvl == IPPROTO_TCP) && (sock->type == SOCK_STREAM))
+                return 0;
+        if (lvl != SOL_TIPC)
+                return -ENOPROTOOPT;
+        if (ol < sizeof(value))
+                return -EINVAL;
+        if ((res = get_user(value, (u32 *)ov)))
+                return res;
+
+        if (down_interruptible(&tsock->sem)) 
+                return -ERESTARTSYS;
+        
+        switch (opt) {
+        case TIPC_IMPORTANCE:
+                res = tipc_set_portimportance(tsock->p->ref, value);
+                break;
+        case TIPC_SRC_DROPPABLE:
+                if (sock->type != SOCK_STREAM)
+                        res = tipc_set_portunreliable(tsock->p->ref, value);
+                else 
+                        res = -ENOPROTOOPT;
+                break;
+        case TIPC_DEST_DROPPABLE:
+                res = tipc_set_portunreturnable(tsock->p->ref, value);
+                break;
+        case TIPC_CONN_TIMEOUT:
+                sock->sk->sk_rcvtimeo = (value * HZ / 1000);
+                break;
+        default:
+                res = -EINVAL;
+        }
+
+        up(&tsock->sem);
+        return res;
+}
+
+/**
+ * getsockopt - get socket option
+ * @sock: socket structure
+ * @lvl: option level
+ * @opt: option identifier
+ * @ov: receptacle for option value
+ * @ol: receptacle for length of option value
+ * 
+ * For stream sockets only, returns 0 length result for all IPPROTO_TCP options 
+ * (to ease compatibility).
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+
+static int getsockopt(struct socket *sock, int lvl, int opt, char *ov, int *ol)
+{
+        struct tipc_sock *tsock = tipc_sk(sock->sk);
+        int len;
+        u32 value;
+        int res;
+
+        if ((lvl == IPPROTO_TCP) && (sock->type == SOCK_STREAM))
+                return put_user(0, ol);
+        if (lvl != SOL_TIPC)
+                return -ENOPROTOOPT;
+        if ((res = get_user(len, ol)))
+                return res;
+
+        if (down_interruptible(&tsock->sem)) 
+                return -ERESTARTSYS;
+
+        switch (opt) {
+        case TIPC_IMPORTANCE:
+                res = tipc_portimportance(tsock->p->ref, &value);
+                break;
+        case TIPC_SRC_DROPPABLE:
+                res = tipc_portunreliable(tsock->p->ref, &value);
+                break;
+        case TIPC_DEST_DROPPABLE:
+                res = tipc_portunreturnable(tsock->p->ref, &value);
+                break;
+        case TIPC_CONN_TIMEOUT:
+                value = (sock->sk->sk_rcvtimeo * 1000) / HZ;
+                break;
+        default:
+                res = -EINVAL;
+        }
+
+        if (res) {
+                /* "get" failed */
+        }
+        else if (len < sizeof(value)) {
+                res = -EINVAL;
+        }
+        else if ((res = copy_to_user(ov, &value, sizeof(value)))) {
+                /* couldn't return value */
+        }
+        else {
+                res = put_user(sizeof(value), ol);
+        }
+
+        up(&tsock->sem);
+        return res;
+}
+
+/**
+ * Placeholders for non-implemented functionality
+ * 
+ * Returns error code (POSIX-compliant where defined)
+ */
+
+static int ioctl(struct socket *s, u32 cmd, unsigned long arg)
+{
+        return -EINVAL;
+}
+
+static int no_mmap(struct file *file, struct socket *sock,
+                   struct vm_area_struct *vma)
+{
+        return -EINVAL;
+}
+static ssize_t no_sendpage(struct socket *sock, struct page *page,
+                           int offset, size_t size, int flags)
+{
+        return -EINVAL;
+}
+
+static int no_skpair(struct socket *s1, struct socket *s2)
+{
+        return -EOPNOTSUPP;
+}
+
+/**
+ * Protocol switches for the various types of TIPC sockets
+ */
+
+static struct proto_ops msg_ops = {
+        .owner          = THIS_MODULE,
+        .family         = AF_TIPC,
+        .release        = release,
+        .bind           = bind,
+        .connect        = connect,
+        .socketpair     = no_skpair,
+        .accept         = accept,
+        .getname        = get_name,
+        .poll           = poll,
+        .ioctl          = ioctl,
+        .listen         = listen,
+        .shutdown       = shutdown,
+        .setsockopt     = setsockopt,
+        .getsockopt     = getsockopt,
+        .sendmsg        = send_msg,
+        .recvmsg        = recv_msg,
+        .mmap           = no_mmap,
+        .sendpage       = no_sendpage
+};
+
+static struct proto_ops packet_ops = {
+        .owner          = THIS_MODULE,
+        .family         = AF_TIPC,
+        .release        = release,
+        .bind           = bind,
+        .connect        = connect,
+        .socketpair     = no_skpair,
+        .accept         = accept,
+        .getname        = get_name,
+        .poll           = poll,
+        .ioctl          = ioctl,
+        .listen         = listen,
+        .shutdown       = shutdown,
+        .setsockopt     = setsockopt,
+        .getsockopt     = getsockopt,
+        .sendmsg        = send_packet,
+        .recvmsg        = recv_msg,
+        .mmap           = no_mmap,
+        .sendpage       = no_sendpage
+};
+
+static struct proto_ops stream_ops = {
+        .owner          = THIS_MODULE,
+        .family         = AF_TIPC,
+        .release        = release,
+        .bind           = bind,
+        .connect        = connect,
+        .socketpair     = no_skpair,
+        .accept         = accept,
+        .getname        = get_name,
+        .poll           = poll,
+        .ioctl          = ioctl,
+        .listen         = listen,
+        .shutdown       = shutdown,
+        .setsockopt     = setsockopt,
+        .getsockopt     = getsockopt,
+        .sendmsg        = send_stream,
+        .recvmsg        = recv_stream,
+        .mmap           = no_mmap,
+        .sendpage       = no_sendpage
+};
+
+static struct net_proto_family tipc_family_ops = {
+        .owner          = THIS_MODULE,
+        .family         = AF_TIPC,
+        .create         = tipc_create
+};
+
+static struct proto tipc_proto = {
+        .name           = "TIPC",
+        .owner          = THIS_MODULE,
+        .obj_size       = sizeof(struct tipc_sock)
+};
+
+/**
+ * socket_init - initialize TIPC socket interface
+ * 
+ * Returns 0 on success, errno otherwise
+ */
+int socket_init(void)
+{
+        int res;
+
+        res = proto_register(&tipc_proto, 1);
+        if (res) {
+                err("Unable to register TIPC protocol type\n");
+                goto out;
+        }
+
+        res = sock_register(&tipc_family_ops);
+        if (res) {
+                err("Unable to register TIPC socket type\n");
+                proto_unregister(&tipc_proto);
+                goto out;
+        }
+
+        sockets_enabled = 1;
+ out:
+        return res;
+}
+
+/**
+ * sock_stop - stop TIPC socket interface
+ */
+void socket_stop(void)
+{
+        if (!sockets_enabled)
+                return;
+
+        sockets_enabled = 0;
+        sock_unregister(tipc_family_ops.family);
+        proto_unregister(&tipc_proto);
+}
+