svcsock.c

Linux Kernel 2.6.9 for OMAP1710

	memcpy(xbufp->head[0].iov_base, &reclen, 4);

	if (test_bit(SK_DEAD, &rqstp->rq_sock->sk_flags))
		return -ENOTCONN;

	sent = svc_sendto(rqstp, &rqstp->rq_res);
	if (sent != xbufp->len) {
		printk(KERN_NOTICE "rpc-srv/tcp: %s: %s %d when sending %d bytes - shutting down socket\n",
		       rqstp->rq_sock->sk_server->sv_name,
		       (sent<0)?"got error":"sent only",
		       sent, xbufp->len);
		svc_delete_socket(rqstp->rq_sock);
		sent = -EAGAIN;
	}
	return sent;
}

static void
svc_tcp_init(struct svc_sock *svsk)
{
	struct sock	*sk = svsk->sk_sk;
	struct tcp_opt  *tp = tcp_sk(sk);

	svsk->sk_recvfrom = svc_tcp_recvfrom;
	svsk->sk_sendto = svc_tcp_sendto;

	if (sk->sk_state == TCP_LISTEN) {
		dprintk("setting up TCP socket for listening\n");
		sk->sk_data_ready = svc_tcp_listen_data_ready;
		set_bit(SK_CONN, &svsk->sk_flags);
	} else {
		dprintk("setting up TCP socket for reading\n");
		sk->sk_state_change = svc_tcp_state_change;
		sk->sk_data_ready = svc_tcp_data_ready;
		sk->sk_write_space = svc_write_space;

		svsk->sk_reclen = 0;
		svsk->sk_tcplen = 0;

		tp->nonagle = 1;        /* disable Nagle's algorithm */

		/* initialise setting must have enough space to
		 * receive and respond to one request.  
		 * svc_tcp_recvfrom will re-adjust if necessary
		 */
		svc_sock_setbufsize(svsk->sk_sock,
				    3 * svsk->sk_server->sv_bufsz,
				    3 * svsk->sk_server->sv_bufsz);

		set_bit(SK_CHNGBUF, &svsk->sk_flags);
		set_bit(SK_DATA, &svsk->sk_flags);
		if (sk->sk_state != TCP_ESTABLISHED) 
			set_bit(SK_CLOSE, &svsk->sk_flags);
	}
}

void
svc_sock_update_bufs(struct svc_serv *serv)
{
	/*
	 * The number of server threads has changed. Update
	 * rcvbuf and sndbuf accordingly on all sockets
	 */
	struct list_head *le;

	spin_lock_bh(&serv->sv_lock);
	list_for_each(le, &serv->sv_permsocks) {
		struct svc_sock *svsk = 
			list_entry(le, struct svc_sock, sk_list);
		set_bit(SK_CHNGBUF, &svsk->sk_flags);
	}
	list_for_each(le, &serv->sv_tempsocks) {
		struct svc_sock *svsk =
			list_entry(le, struct svc_sock, sk_list);
		set_bit(SK_CHNGBUF, &svsk->sk_flags);
	}
	spin_unlock_bh(&serv->sv_lock);
}

/*
 * Receive the next request on any socket.
 */
int
svc_recv(struct svc_serv *serv, struct svc_rqst *rqstp, long timeout)
{
	struct svc_sock		*svsk =NULL;
	int			len;
	int 			pages;
	struct xdr_buf		*arg;
	DECLARE_WAITQUEUE(wait, current);

	dprintk("svc: server %p waiting for data (to = %ld)\n",
		rqstp, timeout);

	if (rqstp->rq_sock)
		printk(KERN_ERR 
			"svc_recv: service %p, socket not NULL!\n",
			 rqstp);
	if (waitqueue_active(&rqstp->rq_wait))
		printk(KERN_ERR 
			"svc_recv: service %p, wait queue active!\n",
			 rqstp);

	/* Initialize the buffers */
	/* first reclaim pages that were moved to response list */
	svc_pushback_allpages(rqstp);

	/* now allocate needed pages.  If we get a failure, sleep briefly */
	pages = 2 + (serv->sv_bufsz + PAGE_SIZE -1) / PAGE_SIZE;
	while (rqstp->rq_arghi < pages) {
		struct page *p = alloc_page(GFP_KERNEL);
		if (!p) {
			set_current_state(TASK_UNINTERRUPTIBLE);
			schedule_timeout(HZ/2);
			continue;
		}
		rqstp->rq_argpages[rqstp->rq_arghi++] = p;
	}

	/* Make arg->head point to first page and arg->pages point to rest */
	arg = &rqstp->rq_arg;
	arg->head[0].iov_base = page_address(rqstp->rq_argpages[0]);
	arg->head[0].iov_len = PAGE_SIZE;
	rqstp->rq_argused = 1;
	arg->pages = rqstp->rq_argpages + 1;
	arg->page_base = 0;
	/* save at least one page for response */
	arg->page_len = (pages-2)*PAGE_SIZE;
	arg->len = (pages-1)*PAGE_SIZE;
	arg->tail[0].iov_len = 0;
	
	if (signalled())
		return -EINTR;

	spin_lock_bh(&serv->sv_lock);
	if (!list_empty(&serv->sv_tempsocks)) {
		svsk = list_entry(serv->sv_tempsocks.next,
				  struct svc_sock, sk_list);
		/* apparently the "standard" is that clients close
		 * idle connections after 5 minutes, servers after
		 * 6 minutes
		 *   http://www.connectathon.org/talks96/nfstcp.pdf 
		 */
		if (get_seconds() - svsk->sk_lastrecv < 6*60
		    || test_bit(SK_BUSY, &svsk->sk_flags))
			svsk = NULL;
	}
	if (svsk) {
		set_bit(SK_BUSY, &svsk->sk_flags);
		set_bit(SK_CLOSE, &svsk->sk_flags);
		rqstp->rq_sock = svsk;
		svsk->sk_inuse++;
	} else if ((svsk = svc_sock_dequeue(serv)) != NULL) {
		rqstp->rq_sock = svsk;
		svsk->sk_inuse++;
		rqstp->rq_reserved = serv->sv_bufsz;	
		svsk->sk_reserved += rqstp->rq_reserved;
	} else {
		/* No data pending. Go to sleep */
		svc_serv_enqueue(serv, rqstp);

		/*
		 * We have to be able to interrupt this wait
		 * to bring down the daemons ...
		 */
		set_current_state(TASK_INTERRUPTIBLE);
		add_wait_queue(&rqstp->rq_wait, &wait);
		spin_unlock_bh(&serv->sv_lock);

		schedule_timeout(timeout);

		if (current->flags & PF_FREEZE)
			refrigerator(PF_FREEZE);

		spin_lock_bh(&serv->sv_lock);
		remove_wait_queue(&rqstp->rq_wait, &wait);

		if (!(svsk = rqstp->rq_sock)) {
			svc_serv_dequeue(serv, rqstp);
			spin_unlock_bh(&serv->sv_lock);
			dprintk("svc: server %p, no data yet\n", rqstp);
			return signalled()? -EINTR : -EAGAIN;
		}
	}
	spin_unlock_bh(&serv->sv_lock);

	dprintk("svc: server %p, socket %p, inuse=%d\n",
		 rqstp, svsk, svsk->sk_inuse);
	len = svsk->sk_recvfrom(rqstp);
	dprintk("svc: got len=%d\n", len);

	/* No data, incomplete (TCP) read, or accept() */
	if (len == 0 || len == -EAGAIN) {
		rqstp->rq_res.len = 0;
		svc_sock_release(rqstp);
		return -EAGAIN;
	}
	svsk->sk_lastrecv = get_seconds();
	if (test_bit(SK_TEMP, &svsk->sk_flags)) {
		/* push active sockets to end of list */
		spin_lock_bh(&serv->sv_lock);
		if (!list_empty(&svsk->sk_list))
			list_move_tail(&svsk->sk_list, &serv->sv_tempsocks);
		spin_unlock_bh(&serv->sv_lock);
	}

	rqstp->rq_secure  = ntohs(rqstp->rq_addr.sin_port) < 1024;
	rqstp->rq_chandle.defer = svc_defer;

	if (serv->sv_stats)
		serv->sv_stats->netcnt++;
	return len;
}

/* 
 * Drop request
 */
void
svc_drop(struct svc_rqst *rqstp)
{
	dprintk("svc: socket %p dropped request\n", rqstp->rq_sock);
	svc_sock_release(rqstp);
}

/*
 * Return reply to client.
 */
int
svc_send(struct svc_rqst *rqstp)
{
	struct svc_sock	*svsk;
	int		len;
	struct xdr_buf	*xb;

	if ((svsk = rqstp->rq_sock) == NULL) {
		printk(KERN_WARNING "NULL socket pointer in %s:%d\n",
				__FILE__, __LINE__);
		return -EFAULT;
	}

	/* release the receive skb before sending the reply */
	svc_release_skb(rqstp);

	/* calculate over-all length */
	xb = & rqstp->rq_res;
	xb->len = xb->head[0].iov_len +
		xb->page_len +
		xb->tail[0].iov_len;

	/* Grab svsk->sk_sem to serialize outgoing data. */
	down(&svsk->sk_sem);
	if (test_bit(SK_DEAD, &svsk->sk_flags))
		len = -ENOTCONN;
	else
		len = svsk->sk_sendto(rqstp);
	up(&svsk->sk_sem);
	svc_sock_release(rqstp);

	if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
		return 0;
	return len;
}

/*
 * Initialize socket for RPC use and create svc_sock struct
 * XXX: May want to setsockopt SO_SNDBUF and SO_RCVBUF.
 */
static struct svc_sock *
svc_setup_socket(struct svc_serv *serv, struct socket *sock,
					int *errp, int pmap_register)
{
	struct svc_sock	*svsk;
	struct sock	*inet;

	dprintk("svc: svc_setup_socket %p\n", sock);
	if (!(svsk = kmalloc(sizeof(*svsk), GFP_KERNEL))) {
		*errp = -ENOMEM;
		return NULL;
	}
	memset(svsk, 0, sizeof(*svsk));

	inet = sock->sk;

	/* Register socket with portmapper */
	if (*errp >= 0 && pmap_register)
		*errp = svc_register(serv, inet->sk_protocol,
				     ntohs(inet_sk(inet)->sport));

	if (*errp < 0) {
		kfree(svsk);
		return NULL;
	}

	set_bit(SK_BUSY, &svsk->sk_flags);
	inet->sk_user_data = svsk;
	svsk->sk_sock = sock;
	svsk->sk_sk = inet;
	svsk->sk_ostate = inet->sk_state_change;
	svsk->sk_odata = inet->sk_data_ready;
	svsk->sk_owspace = inet->sk_write_space;
	svsk->sk_server = serv;
	svsk->sk_lastrecv = get_seconds();
	INIT_LIST_HEAD(&svsk->sk_deferred);
	INIT_LIST_HEAD(&svsk->sk_ready);
	sema_init(&svsk->sk_sem, 1);

	/* Initialize the socket */
	if (sock->type == SOCK_DGRAM)
		svc_udp_init(svsk);
	else
		svc_tcp_init(svsk);

	spin_lock_bh(&serv->sv_lock);
	if (!pmap_register) {
		set_bit(SK_TEMP, &svsk->sk_flags);
		list_add(&svsk->sk_list, &serv->sv_tempsocks);
		serv->sv_tmpcnt++;
	} else {
		clear_bit(SK_TEMP, &svsk->sk_flags);
		list_add(&svsk->sk_list, &serv->sv_permsocks);
	}
	spin_unlock_bh(&serv->sv_lock);

	dprintk("svc: svc_setup_socket created %p (inet %p)\n",
				svsk, svsk->sk_sk);

	clear_bit(SK_BUSY, &svsk->sk_flags);
	svc_sock_enqueue(svsk);
	return svsk;
}

/*
 * Create socket for RPC service.
 */
static int
svc_create_socket(struct svc_serv *serv, int protocol, struct sockaddr_in *sin)
{
	struct svc_sock	*svsk;
	struct socket	*sock;
	int		error;
	int		type;

	dprintk("svc: svc_create_socket(%s, %d, %u.%u.%u.%u:%d)\n",
				serv->sv_program->pg_name, protocol,
				NIPQUAD(sin->sin_addr.s_addr),
				ntohs(sin->sin_port));

	if (protocol != IPPROTO_UDP && protocol != IPPROTO_TCP) {
		printk(KERN_WARNING "svc: only UDP and TCP "
				"sockets supported\n");
		return -EINVAL;
	}
	type = (protocol == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;

	if ((error = sock_create_kern(PF_INET, type, protocol, &sock)) < 0)
		return error;

	if (sin != NULL) {
		if (type == SOCK_STREAM)
			sock->sk->sk_reuse = 1; /* allow address reuse */
		error = sock->ops->bind(sock, (struct sockaddr *) sin,
						sizeof(*sin));
		if (error < 0)
			goto bummer;
	}

	if (protocol == IPPROTO_TCP) {
		if ((error = sock->ops->listen(sock, 64)) < 0)
			goto bummer;
	}

	if ((svsk = svc_setup_socket(serv, sock, &error, 1)) != NULL)
		return 0;

bummer:
	dprintk("svc: svc_create_socket error = %d\n", -error);
	sock_release(sock);
	return error;
}

/*
 * Remove a dead socket
 */
void
svc_delete_socket(struct svc_sock *svsk)
{
	struct svc_serv	*serv;
	struct sock	*sk;

	dprintk("svc: svc_delete_socket(%p)\n", svsk);

	serv = svsk->sk_server;
	sk = svsk->sk_sk;

	sk->sk_state_change = svsk->sk_ostate;
	sk->sk_data_ready = svsk->sk_odata;
	sk->sk_write_space = svsk->sk_owspace;

	spin_lock_bh(&serv->sv_lock);

	list_del_init(&svsk->sk_list);
	list_del_init(&svsk->sk_ready);
	if (!test_and_set_bit(SK_DEAD, &svsk->sk_flags))
		if (test_bit(SK_TEMP, &svsk->sk_flags))
			serv->sv_tmpcnt--;

	if (!svsk->sk_inuse) {
		spin_unlock_bh(&serv->sv_lock);
		sock_release(svsk->sk_sock);
		kfree(svsk);
	} else {
		spin_unlock_bh(&serv->sv_lock);
		dprintk(KERN_NOTICE "svc: server socket destroy delayed\n");
		/* svsk->sk_server = NULL; */
	}
}

/*
 * Make a socket for nfsd and lockd
 */
int
svc_makesock(struct svc_serv *serv, int protocol, unsigned short port)
{
	struct sockaddr_in	sin;

	dprintk("svc: creating socket proto = %d\n", protocol);
	sin.sin_family      = AF_INET;
	sin.sin_addr.s_addr = INADDR_ANY;
	sin.sin_port        = htons(port);
	return svc_create_socket(serv, protocol, &sin);
}

/*
 * Handle defer and revisit of requests 
 */

static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
{
	struct svc_deferred_req *dr = container_of(dreq, struct svc_deferred_req, handle);
	struct svc_serv *serv = dreq->owner;
	struct svc_sock *svsk;

	if (too_many) {
		svc_sock_put(dr->svsk);
		kfree(dr);
		return;
	}
	dprintk("revisit queued\n");
	svsk = dr->svsk;
	dr->svsk = NULL;
	spin_lock_bh(&serv->sv_lock);
	list_add(&dr->handle.recent, &svsk->sk_deferred);
	spin_unlock_bh(&serv->sv_lock);
	set_bit(SK_DEFERRED, &svsk->sk_flags);
	svc_sock_enqueue(svsk);
	svc_sock_put(svsk);
}

static struct cache_deferred_req *
svc_defer(struct cache_req *req)
{
	struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
	int size = sizeof(struct svc_deferred_req) + (rqstp->rq_arg.len);
	struct svc_deferred_req *dr;

	if (rqstp->rq_arg.page_len)
		return NULL; /* if more than a page, give up FIXME */
	if (rqstp->rq_deferred) {
		dr = rqstp->rq_deferred;
		rqstp->rq_deferred = NULL;
	} else {
		int skip  = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
		/* FIXME maybe discard if size too large */
		dr = kmalloc(size, GFP_KERNEL);
		if (dr == NULL)
			return NULL;

		dr->handle.owner = rqstp->rq_server;
		dr->prot = rqstp->rq_prot;
		dr->addr = rqstp->rq_addr;
		dr->argslen = rqstp->rq_arg.len >> 2;
		memcpy(dr->args, rqstp->rq_arg.head[0].iov_base-skip, dr->argslen<<2);
	}
	spin_lock_bh(&rqstp->rq_server->sv_lock);
	rqstp->rq_sock->sk_inuse++;
	dr->svsk = rqstp->rq_sock;
	spin_unlock_bh(&rqstp->rq_server->sv_lock);

	dr->handle.revisit = svc_revisit;
	return &dr->handle;
}

/*
 * recv data from a deferred request into an active one
 */
static int svc_deferred_recv(struct svc_rqst *rqstp)
{
	struct svc_deferred_req *dr = rqstp->rq_deferred;

	rqstp->rq_arg.head[0].iov_base = dr->args;
	rqstp->rq_arg.head[0].iov_len = dr->argslen<<2;
	rqstp->rq_arg.page_len = 0;
	rqstp->rq_arg.len = dr->argslen<<2;
	rqstp->rq_prot        = dr->prot;
	rqstp->rq_addr        = dr->addr;
	return dr->argslen<<2;
}


static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk)
{
	struct svc_deferred_req *dr = NULL;
	struct svc_serv	*serv = svsk->sk_server;
	
	if (!test_bit(SK_DEFERRED, &svsk->sk_flags))
		return NULL;
	spin_lock_bh(&serv->sv_lock);
	clear_bit(SK_DEFERRED, &svsk->sk_flags);
	if (!list_empty(&svsk->sk_deferred)) {
		dr = list_entry(svsk->sk_deferred.next,
				struct svc_deferred_req,
				handle.recent);
		list_del_init(&dr->handle.recent);
		set_bit(SK_DEFERRED, &svsk->sk_flags);
	}
	spin_unlock_bh(&serv->sv_lock);
	return dr;
}