1 files changed, 366 insertions, 0 deletions

diff --git a/net/rxrpc/ar-recvmsg.c b/net/rxrpc/ar-recvmsg.c
new file mode 100644
index 00000000000..e947d5c1590
--- /dev/null
+++ b/net/rxrpc/ar-recvmsg.c
@@ -0,0 +1,366 @@
+/* RxRPC recvmsg() implementation
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+/*
+ * removal a call's user ID from the socket tree to make the user ID available
+ * again and so that it won't be seen again in association with that call
+ */
+static void rxrpc_remove_user_ID(struct rxrpc_sock *rx, struct rxrpc_call *call)
+{
+	_debug("RELEASE CALL %d", call->debug_id);
+
+	if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
+		write_lock_bh(&rx->call_lock);
+		rb_erase(&call->sock_node, &call->socket->calls);
+		clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
+		write_unlock_bh(&rx->call_lock);
+	}
+
+	read_lock_bh(&call->state_lock);
+	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
+	    !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
+		schedule_work(&call->processor);
+	read_unlock_bh(&call->state_lock);
+}
+
+/*
+ * receive a message from an RxRPC socket
+ * - we need to be careful about two or more threads calling recvmsg
+ *   simultaneously
+ */
+int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock,
+		  struct msghdr *msg, size_t len, int flags)
+{
+	struct rxrpc_skb_priv *sp;
+	struct rxrpc_call *call = NULL, *continue_call = NULL;
+	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
+	struct sk_buff *skb;
+	long timeo;
+	int copy, ret, ullen, offset, copied = 0;
+	u32 abort_code;
+
+	DEFINE_WAIT(wait);
+
+	_enter(",,,%zu,%d", len, flags);
+
+	if (flags & (MSG_OOB | MSG_TRUNC))
+		return -EOPNOTSUPP;
+
+	ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
+
+	timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
+	msg->msg_flags |= MSG_MORE;
+
+	lock_sock(&rx->sk);
+
+	for (;;) {
+		/* return immediately if a client socket has no outstanding
+		 * calls */
+		if (RB_EMPTY_ROOT(&rx->calls)) {
+			if (copied)
+				goto out;
+			if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
+				release_sock(&rx->sk);
+				if (continue_call)
+					rxrpc_put_call(continue_call);
+				return -ENODATA;
+			}
+		}
+
+		/* get the next message on the Rx queue */
+		skb = skb_peek(&rx->sk.sk_receive_queue);
+		if (!skb) {
+			/* nothing remains on the queue */
+			if (copied &&
+			    (msg->msg_flags & MSG_PEEK || timeo == 0))
+				goto out;
+
+			/* wait for a message to turn up */
+			release_sock(&rx->sk);
+			prepare_to_wait_exclusive(rx->sk.sk_sleep, &wait,
+						  TASK_INTERRUPTIBLE);
+			ret = sock_error(&rx->sk);
+			if (ret)
+				goto wait_error;
+
+			if (skb_queue_empty(&rx->sk.sk_receive_queue)) {
+				if (signal_pending(current))
+					goto wait_interrupted;
+				timeo = schedule_timeout(timeo);
+			}
+			finish_wait(rx->sk.sk_sleep, &wait);
+			lock_sock(&rx->sk);
+			continue;
+		}
+
+	peek_next_packet:
+		sp = rxrpc_skb(skb);
+		call = sp->call;
+		ASSERT(call != NULL);
+
+		_debug("next pkt %s", rxrpc_pkts[sp->hdr.type]);
+
+		/* make sure we wait for the state to be updated in this call */
+		spin_lock_bh(&call->lock);
+		spin_unlock_bh(&call->lock);
+
+		if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
+			_debug("packet from released call");
+			if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
+				BUG();
+			rxrpc_free_skb(skb);
+			continue;
+		}
+
+		/* determine whether to continue last data receive */
+		if (continue_call) {
+			_debug("maybe cont");
+			if (call != continue_call ||
+			    skb->mark != RXRPC_SKB_MARK_DATA) {
+				release_sock(&rx->sk);
+				rxrpc_put_call(continue_call);
+				_leave(" = %d [noncont]", copied);
+				return copied;
+			}
+		}
+
+		rxrpc_get_call(call);
+
+		/* copy the peer address and timestamp */
+		if (!continue_call) {
+			if (msg->msg_name && msg->msg_namelen > 0)
+				memcpy(&msg->msg_name, &call->conn->trans->peer->srx,
+				       sizeof(call->conn->trans->peer->srx));
+			sock_recv_timestamp(msg, &rx->sk, skb);
+		}
+
+		/* receive the message */
+		if (skb->mark != RXRPC_SKB_MARK_DATA)
+			goto receive_non_data_message;
+
+		_debug("recvmsg DATA #%u { %d, %d }",
+		       ntohl(sp->hdr.seq), skb->len, sp->offset);
+
+		if (!continue_call) {
+			/* only set the control data once per recvmsg() */
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+				       ullen, &call->user_call_ID);
+			if (ret < 0)
+				goto copy_error;
+			ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
+		}
+
+		ASSERTCMP(ntohl(sp->hdr.seq), >=, call->rx_data_recv);
+		ASSERTCMP(ntohl(sp->hdr.seq), <=, call->rx_data_recv + 1);
+		call->rx_data_recv = ntohl(sp->hdr.seq);
+
+		ASSERTCMP(ntohl(sp->hdr.seq), >, call->rx_data_eaten);
+
+		offset = sp->offset;
+		copy = skb->len - offset;
+		if (copy > len - copied)
+			copy = len - copied;
+
+		if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
+			ret = skb_copy_datagram_iovec(skb, offset,
+						      msg->msg_iov, copy);
+		} else {
+			ret = skb_copy_and_csum_datagram_iovec(skb, offset,
+							       msg->msg_iov);
+			if (ret == -EINVAL)
+				goto csum_copy_error;
+		}
+
+		if (ret < 0)
+			goto copy_error;
+
+		/* handle piecemeal consumption of data packets */
+		_debug("copied %d+%d", copy, copied);
+
+		offset += copy;
+		copied += copy;
+
+		if (!(flags & MSG_PEEK))
+			sp->offset = offset;
+
+		if (sp->offset < skb->len) {
+			_debug("buffer full");
+			ASSERTCMP(copied, ==, len);
+			break;
+		}
+
+		/* we transferred the whole data packet */
+		if (sp->hdr.flags & RXRPC_LAST_PACKET) {
+			_debug("last");
+			if (call->conn->out_clientflag) {
+				 /* last byte of reply received */
+				ret = copied;
+				goto terminal_message;
+			}
+
+			/* last bit of request received */
+			if (!(flags & MSG_PEEK)) {
+				_debug("eat packet");
+				if (skb_dequeue(&rx->sk.sk_receive_queue) !=
+				    skb)
+					BUG();
+				rxrpc_free_skb(skb);
+			}
+			msg->msg_flags &= ~MSG_MORE;
+			break;
+		}
+
+		/* move on to the next data message */
+		_debug("next");
+		if (!continue_call)
+			continue_call = sp->call;
+		else
+			rxrpc_put_call(call);
+		call = NULL;
+
+		if (flags & MSG_PEEK) {
+			_debug("peek next");
+			skb = skb->next;
+			if (skb == (struct sk_buff *) &rx->sk.sk_receive_queue)
+				break;
+			goto peek_next_packet;
+		}
+
+		_debug("eat packet");
+		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
+			BUG();
+		rxrpc_free_skb(skb);
+	}
+
+	/* end of non-terminal data packet reception for the moment */
+	_debug("end rcv data");
+out:
+	release_sock(&rx->sk);
+	if (call)
+		rxrpc_put_call(call);
+	if (continue_call)
+		rxrpc_put_call(continue_call);
+	_leave(" = %d [data]", copied);
+	return copied;
+
+	/* handle non-DATA messages such as aborts, incoming connections and
+	 * final ACKs */
+receive_non_data_message:
+	_debug("non-data");
+
+	if (skb->mark == RXRPC_SKB_MARK_NEW_CALL) {
+		_debug("RECV NEW CALL");
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &abort_code);
+		if (ret < 0)
+			goto copy_error;
+		if (!(flags & MSG_PEEK)) {
+			if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
+				BUG();
+			rxrpc_free_skb(skb);
+		}
+		goto out;
+	}
+
+	ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+		       ullen, &call->user_call_ID);
+	if (ret < 0)
+		goto copy_error;
+	ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
+
+	switch (skb->mark) {
+	case RXRPC_SKB_MARK_DATA:
+		BUG();
+	case RXRPC_SKB_MARK_FINAL_ACK:
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
+		break;
+	case RXRPC_SKB_MARK_BUSY:
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
+		break;
+	case RXRPC_SKB_MARK_REMOTE_ABORT:
+		abort_code = call->abort_code;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
+		break;
+	case RXRPC_SKB_MARK_NET_ERROR:
+		_debug("RECV NET ERROR %d", sp->error);
+		abort_code = sp->error;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &abort_code);
+		break;
+	case RXRPC_SKB_MARK_LOCAL_ERROR:
+		_debug("RECV LOCAL ERROR %d", sp->error);
+		abort_code = sp->error;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
+			       &abort_code);
+		break;
+	default:
+		BUG();
+		break;
+	}
+
+	if (ret < 0)
+		goto copy_error;
+
+terminal_message:
+	_debug("terminal");
+	msg->msg_flags &= ~MSG_MORE;
+	msg->msg_flags |= MSG_EOR;
+
+	if (!(flags & MSG_PEEK)) {
+		_net("free terminal skb %p", skb);
+		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
+			BUG();
+		rxrpc_free_skb(skb);
+		rxrpc_remove_user_ID(rx, call);
+	}
+
+	release_sock(&rx->sk);
+	rxrpc_put_call(call);
+	if (continue_call)
+		rxrpc_put_call(continue_call);
+	_leave(" = %d", ret);
+	return ret;
+
+copy_error:
+	_debug("copy error");
+	release_sock(&rx->sk);
+	rxrpc_put_call(call);
+	if (continue_call)
+		rxrpc_put_call(continue_call);
+	_leave(" = %d", ret);
+	return ret;
+
+csum_copy_error:
+	_debug("csum error");
+	release_sock(&rx->sk);
+	if (continue_call)
+		rxrpc_put_call(continue_call);
+	rxrpc_kill_skb(skb);
+	skb_kill_datagram(&rx->sk, skb, flags);
+	rxrpc_put_call(call);
+	return -EAGAIN;
+
+wait_interrupted:
+	ret = sock_intr_errno(timeo);
+wait_error:
+	finish_wait(rx->sk.sk_sleep, &wait);
+	if (continue_call)
+		rxrpc_put_call(continue_call);
+	if (copied)
+		copied = ret;
+	_leave(" = %d [waitfail %d]", copied, ret);
+	return copied;
+
+}