svcsock.c

linux 内核源代码

		 * 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(&pool->sp_lock);

		schedule_timeout(timeout);

		try_to_freeze();

		spin_lock_bh(&pool->sp_lock);
		remove_wait_queue(&rqstp->rq_wait, &wait);

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

	dprintk("svc: server %p, pool %u, socket %p, inuse=%d\n",
		 rqstp, pool->sp_id, svsk, atomic_read(&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();
	clear_bit(SK_OLD, &svsk->sk_flags);

	rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
	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_mutex to serialize outgoing data. */
	mutex_lock(&svsk->sk_mutex);
	if (test_bit(SK_DEAD, &svsk->sk_flags))
		len = -ENOTCONN;
	else
		len = svsk->sk_sendto(rqstp);
	mutex_unlock(&svsk->sk_mutex);
	svc_sock_release(rqstp);

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

/*
 * Timer function to close old temporary sockets, using
 * a mark-and-sweep algorithm.
 */
static void
svc_age_temp_sockets(unsigned long closure)
{
	struct svc_serv *serv = (struct svc_serv *)closure;
	struct svc_sock *svsk;
	struct list_head *le, *next;
	LIST_HEAD(to_be_aged);

	dprintk("svc_age_temp_sockets\n");

	if (!spin_trylock_bh(&serv->sv_lock)) {
		/* busy, try again 1 sec later */
		dprintk("svc_age_temp_sockets: busy\n");
		mod_timer(&serv->sv_temptimer, jiffies + HZ);
		return;
	}

	list_for_each_safe(le, next, &serv->sv_tempsocks) {
		svsk = list_entry(le, struct svc_sock, sk_list);

		if (!test_and_set_bit(SK_OLD, &svsk->sk_flags))
			continue;
		if (atomic_read(&svsk->sk_inuse) > 1 || test_bit(SK_BUSY, &svsk->sk_flags))
			continue;
		atomic_inc(&svsk->sk_inuse);
		list_move(le, &to_be_aged);
		set_bit(SK_CLOSE, &svsk->sk_flags);
		set_bit(SK_DETACHED, &svsk->sk_flags);
	}
	spin_unlock_bh(&serv->sv_lock);

	while (!list_empty(&to_be_aged)) {
		le = to_be_aged.next;
		/* fiddling the sk_list node is safe 'cos we're SK_DETACHED */
		list_del_init(le);
		svsk = list_entry(le, struct svc_sock, sk_list);

		dprintk("queuing svsk %p for closing, %lu seconds old\n",
			svsk, get_seconds() - svsk->sk_lastrecv);

		/* a thread will dequeue and close it soon */
		svc_sock_enqueue(svsk);
		svc_sock_put(svsk);
	}

	mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
}

/*
 * 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 flags)
{
	struct svc_sock	*svsk;
	struct sock	*inet;
	int		pmap_register = !(flags & SVC_SOCK_ANONYMOUS);
	int		is_temporary = flags & SVC_SOCK_TEMPORARY;

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

	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;
	atomic_set(&svsk->sk_inuse, 1);
	svsk->sk_lastrecv = get_seconds();
	spin_lock_init(&svsk->sk_lock);
	INIT_LIST_HEAD(&svsk->sk_deferred);
	INIT_LIST_HEAD(&svsk->sk_ready);
	mutex_init(&svsk->sk_mutex);

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

	spin_lock_bh(&serv->sv_lock);
	if (is_temporary) {
		set_bit(SK_TEMP, &svsk->sk_flags);
		list_add(&svsk->sk_list, &serv->sv_tempsocks);
		serv->sv_tmpcnt++;
		if (serv->sv_temptimer.function == NULL) {
			/* setup timer to age temp sockets */
			setup_timer(&serv->sv_temptimer, svc_age_temp_sockets,
					(unsigned long)serv);
			mod_timer(&serv->sv_temptimer,
					jiffies + svc_conn_age_period * HZ);
		}
	} 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);

	return svsk;
}

int svc_addsock(struct svc_serv *serv,
		int fd,
		char *name_return,
		int *proto)
{
	int err = 0;
	struct socket *so = sockfd_lookup(fd, &err);
	struct svc_sock *svsk = NULL;

	if (!so)
		return err;
	if (so->sk->sk_family != AF_INET)
		err =  -EAFNOSUPPORT;
	else if (so->sk->sk_protocol != IPPROTO_TCP &&
	    so->sk->sk_protocol != IPPROTO_UDP)
		err =  -EPROTONOSUPPORT;
	else if (so->state > SS_UNCONNECTED)
		err = -EISCONN;
	else {
		svsk = svc_setup_socket(serv, so, &err, SVC_SOCK_DEFAULTS);
		if (svsk) {
			svc_sock_received(svsk);
			err = 0;
		}
	}
	if (err) {
		sockfd_put(so);
		return err;
	}
	if (proto) *proto = so->sk->sk_protocol;
	return one_sock_name(name_return, svsk);
}
EXPORT_SYMBOL_GPL(svc_addsock);

/*
 * Create socket for RPC service.
 */
static int svc_create_socket(struct svc_serv *serv, int protocol,
				struct sockaddr *sin, int len, int flags)
{
	struct svc_sock	*svsk;
	struct socket	*sock;
	int		error;
	int		type;
	char		buf[RPC_MAX_ADDRBUFLEN];

	dprintk("svc: svc_create_socket(%s, %d, %s)\n",
			serv->sv_program->pg_name, protocol,
			__svc_print_addr(sin, buf, sizeof(buf)));

	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;

	error = sock_create_kern(sin->sa_family, type, protocol, &sock);
	if (error < 0)
		return error;

	svc_reclassify_socket(sock);

	if (type == SOCK_STREAM)
		sock->sk->sk_reuse = 1;		/* allow address reuse */
	error = kernel_bind(sock, sin, len);
	if (error < 0)
		goto bummer;

	if (protocol == IPPROTO_TCP) {
		if ((error = kernel_listen(sock, 64)) < 0)
			goto bummer;
	}

	if ((svsk = svc_setup_socket(serv, sock, &error, flags)) != NULL) {
		svc_sock_received(svsk);
		return ntohs(inet_sk(svsk->sk_sk)->sport);
	}

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

/*
 * Remove a dead socket
 */
static 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);

	if (!test_and_set_bit(SK_DETACHED, &svsk->sk_flags))
		list_del_init(&svsk->sk_list);
	/*
	 * We used to delete the svc_sock from whichever list
	 * it's sk_ready node was on, but we don't actually
	 * need to.  This is because the only time we're called
	 * while still attached to a queue, the queue itself
	 * is about to be destroyed (in svc_destroy).
	 */
	if (!test_and_set_bit(SK_DEAD, &svsk->sk_flags)) {
		BUG_ON(atomic_read(&svsk->sk_inuse)<2);
		atomic_dec(&svsk->sk_inuse);
		if (test_bit(SK_TEMP, &svsk->sk_flags))
			serv->sv_tmpcnt--;
	}

	spin_unlock_bh(&serv->sv_lock);
}

static void svc_close_socket(struct svc_sock *svsk)
{
	set_bit(SK_CLOSE, &svsk->sk_flags);
	if (test_and_set_bit(SK_BUSY, &svsk->sk_flags))
		/* someone else will have to effect the close */
		return;

	atomic_inc(&svsk->sk_inuse);
	svc_delete_socket(svsk);
	clear_bit(SK_BUSY, &svsk->sk_flags);
	svc_sock_put(svsk);
}

void svc_force_close_socket(struct svc_sock *svsk)
{
	set_bit(SK_CLOSE, &svsk->sk_flags);
	if (test_bit(SK_BUSY, &svsk->sk_flags)) {
		/* Waiting to be processed, but no threads left,
		 * So just remove it from the waiting list
		 */
		list_del_init(&svsk->sk_ready);
		clear_bit(SK_BUSY, &svsk->sk_flags);
	}
	svc_close_socket(svsk);
}

/**
 * svc_makesock - Make a socket for nfsd and lockd
 * @serv: RPC server structure
 * @protocol: transport protocol to use
 * @port: port to use
 * @flags: requested socket characteristics
 *
 */
int svc_makesock(struct svc_serv *serv, int protocol, unsigned short port,
			int flags)
{
	struct sockaddr_in sin = {
		.sin_family		= AF_INET,
		.sin_addr.s_addr	= INADDR_ANY,
		.sin_port		= htons(port),
	};

	dprintk("svc: creating socket proto = %d\n", protocol);
	return svc_create_socket(serv, protocol, (struct sockaddr *) &sin,
							sizeof(sin), flags);
}

/*
 * 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_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(&svsk->sk_lock);
	list_add(&dr->handle.recent, &svsk->sk_deferred);
	spin_unlock(&svsk->sk_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;
		memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
		dr->addrlen = rqstp->rq_addrlen;
		dr->daddr = rqstp->rq_daddr;
		dr->argslen = rqstp->rq_arg.len >> 2;
		memcpy(dr->args, rqstp->rq_arg.head[0].iov_base-skip, dr->argslen<<2);
	}
	atomic_inc(&rqstp->rq_sock->sk_inuse);
	dr->svsk = rqstp->rq_sock;

	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;
	memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
	rqstp->rq_addrlen     = dr->addrlen;
	rqstp->rq_daddr       = dr->daddr;
	rqstp->rq_respages    = rqstp->rq_pages;
	return dr->argslen<<2;
}


static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk)
{
	struct svc_deferred_req *dr = NULL;

	if (!test_bit(SK_DEFERRED, &svsk->sk_flags))
		return NULL;
	spin_lock(&svsk->sk_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(&svsk->sk_lock);
	return dr;
}