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Commit 5d15af67 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tipc-refactor-socket-receive-functions' 



Jon Maloy says:

====================
tipc: refactor socket receive functions

We try to make the functions tipc_sk_recvmsg() and
tipc_sk_recvstream() more readable.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents b0e92279 ec8a09fb

net/tipc/socket.c

+122 −144
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 
#define TIPC_FWD_MSG		1

#define TIPC_MAX_PORT		0xffffffff

#define TIPC_MIN_PORT		1

#define TIPC_ACK_RATE		4       /* ACK at 1/4 of of rcv window size */



enum {

	TIPC_LISTEN = TCP_LISTEN,
@@ -1290,7 +1291,7 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop) 
/**

 * tipc_recvmsg - receive packet-oriented message

 * @m: descriptor for message info

 * @buf_len: total size of user buffer area

 * @buflen: length of user buffer area

 * @flags: receive flags

 *

 * Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages.
@@ -1298,95 +1299,85 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop) 
 *

 * Returns size of returned message data, errno otherwise

 */

static int tipc_recvmsg(struct socket *sock, struct msghdr *m, size_t buf_len,

			int flags)

static int tipc_recvmsg(struct socket *sock, struct msghdr *m,

			size_t buflen,	int flags)

{

	struct sock *sk = sock->sk;

	struct tipc_sock *tsk = tipc_sk(sk);

	struct sk_buff *buf;

	struct tipc_msg *msg;

	bool is_connectionless = tipc_sk_type_connectionless(sk);

	long timeo;

	unsigned int sz;

	u32 err;

	int res, hlen;

	struct sk_buff *skb;

	struct tipc_msg *hdr;

	bool connected = !tipc_sk_type_connectionless(sk);

	int rc, err, hlen, dlen, copy;

	long timeout;



	/* Catch invalid receive requests */

	if (unlikely(!buf_len))

	if (unlikely(!buflen))

		return -EINVAL;



	lock_sock(sk);



	if (!is_connectionless && unlikely(sk->sk_state == TIPC_OPEN)) {

		res = -ENOTCONN;

	if (unlikely(connected && sk->sk_state == TIPC_OPEN)) {

		rc = -ENOTCONN;

		goto exit;

	}

	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);



	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);

restart:



	/* Look for a message in receive queue; wait if necessary */

	res = tipc_wait_for_rcvmsg(sock, &timeo);

	if (res)

	do {

		/* Look at first msg in receive queue; wait if necessary */

		rc = tipc_wait_for_rcvmsg(sock, &timeout);

		if (unlikely(rc))

			goto exit;



	/* Look at first message in receive queue */

	buf = skb_peek(&sk->sk_receive_queue);

	msg = buf_msg(buf);

	sz = msg_data_sz(msg);

	hlen = msg_hdr_sz(msg);

	err = msg_errcode(msg);



	/* Discard an empty non-errored message & try again */

	if ((!sz) && (!err)) {

		skb = skb_peek(&sk->sk_receive_queue);

		hdr = buf_msg(skb);

		dlen = msg_data_sz(hdr);

		hlen = msg_hdr_sz(hdr);

		err = msg_errcode(hdr);

		if (likely(dlen || err))

			break;

		tsk_advance_rx_queue(sk);

		goto restart;

	}

	} while (1);



	/* Capture sender's address (optional) */

	set_orig_addr(m, msg);



	/* Capture ancillary data (optional) */

	res = tipc_sk_anc_data_recv(m, msg, tsk);

	if (res)

	/* Collect msg meta data, including error code and rejected data */

	set_orig_addr(m, hdr);

	rc = tipc_sk_anc_data_recv(m, hdr, tsk);

	if (unlikely(rc))

		goto exit;



	/* Capture message data (if valid) & compute return value (always) */

	if (!err) {

		if (unlikely(buf_len < sz)) {

			sz = buf_len;

	/* Capture data if non-error msg, otherwise just set return value */

	if (likely(!err)) {

		copy = min_t(int, dlen, buflen);

		if (unlikely(copy != dlen))

			m->msg_flags |= MSG_TRUNC;

		}

		res = skb_copy_datagram_msg(buf, hlen, m, sz);

		if (res)

			goto exit;

		res = sz;

		rc = skb_copy_datagram_msg(skb, hlen, m, copy);

	} else {

		if (is_connectionless || err == TIPC_CONN_SHUTDOWN ||

		    m->msg_control)

			res = 0;

		else

			res = -ECONNRESET;

		copy = 0;

		rc = 0;

		if (err != TIPC_CONN_SHUTDOWN && connected && !m->msg_control)

			rc = -ECONNRESET;

	}

	if (unlikely(rc))

		goto exit;



	/* Caption of data or error code/rejected data was successful */

	if (unlikely(flags & MSG_PEEK))

		goto exit;



	if (likely(!is_connectionless)) {

		tsk->rcv_unacked += tsk_inc(tsk, hlen + sz);

		if (unlikely(tsk->rcv_unacked >= (tsk->rcv_win / 4)))

			tipc_sk_send_ack(tsk);

	}

	tsk_advance_rx_queue(sk);

	if (likely(!connected))

		goto exit;



	/* Send connection flow control ack when applicable */

	tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);

	if (tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE)

		tipc_sk_send_ack(tsk);

exit:

	release_sock(sk);

	return res;

	return rc ? rc : copy;

}



/**

 * tipc_recv_stream - receive stream-oriented data

 * tipc_recvstream - receive stream-oriented data

 * @m: descriptor for message info

 * @buf_len: total size of user buffer area

 * @buflen: total size of user buffer area

 * @flags: receive flags

 *

 * Used for SOCK_STREAM messages only.  If not enough data is available
@@ -1394,111 +1385,98 @@ static int tipc_recvmsg(struct socket *sock, struct msghdr *m, size_t buf_len, 
 *

 * Returns size of returned message data, errno otherwise

 */

static int tipc_recv_stream(struct socket *sock, struct msghdr *m,

			    size_t buf_len, int flags)

static int tipc_recvstream(struct socket *sock, struct msghdr *m,

			   size_t buflen, int flags)

{

	struct sock *sk = sock->sk;

	struct tipc_sock *tsk = tipc_sk(sk);

	struct sk_buff *buf;

	struct tipc_msg *msg;

	long timeo;

	unsigned int sz;

	int target;

	int sz_copied = 0;

	u32 err;

	int res = 0, hlen;

	struct sk_buff *skb;

	struct tipc_msg *hdr;

	struct tipc_skb_cb *skb_cb;

	bool peek = flags & MSG_PEEK;

	int offset, required, copy, copied = 0;

	int hlen, dlen, err, rc;

	long timeout;



	/* Catch invalid receive attempts */

	if (unlikely(!buf_len))

	if (unlikely(!buflen))

		return -EINVAL;



	lock_sock(sk);



	if (unlikely(sk->sk_state == TIPC_OPEN)) {

		res = -ENOTCONN;

		rc = -ENOTCONN;

		goto exit;

	}

	required = sock_rcvlowat(sk, flags & MSG_WAITALL, buflen);

	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);



	target = sock_rcvlowat(sk, flags & MSG_WAITALL, buf_len);

	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);



restart:

	/* Look for a message in receive queue; wait if necessary */

	res = tipc_wait_for_rcvmsg(sock, &timeo);

	if (res)

		goto exit;



	/* Look at first message in receive queue */

	buf = skb_peek(&sk->sk_receive_queue);

	msg = buf_msg(buf);

	sz = msg_data_sz(msg);

	hlen = msg_hdr_sz(msg);

	err = msg_errcode(msg);



	/* Discard an empty non-errored message & try again */

	if ((!sz) && (!err)) {

	do {

		/* Look at first msg in receive queue; wait if necessary */

		rc = tipc_wait_for_rcvmsg(sock, &timeout);

		if (unlikely(rc))

			break;

		skb = skb_peek(&sk->sk_receive_queue);

		skb_cb = TIPC_SKB_CB(skb);

		hdr = buf_msg(skb);

		dlen = msg_data_sz(hdr);

		hlen = msg_hdr_sz(hdr);

		err = msg_errcode(hdr);



		/* Discard any empty non-errored (SYN-) message */

		if (unlikely(!dlen && !err)) {

			tsk_advance_rx_queue(sk);

		goto restart;

			continue;

		}



	/* Optionally capture sender's address & ancillary data of first msg */

	if (sz_copied == 0) {

		set_orig_addr(m, msg);

		res = tipc_sk_anc_data_recv(m, msg, tsk);

		if (res)

			goto exit;

		/* Collect msg meta data, incl. error code and rejected data */

		if (!copied) {

			set_orig_addr(m, hdr);

			rc = tipc_sk_anc_data_recv(m, hdr, tsk);

			if (rc)

				break;

		}



	/* Capture message data (if valid) & compute return value (always) */

	if (!err) {

		u32 offset = TIPC_SKB_CB(buf)->bytes_read;

		u32 needed;

		int sz_to_copy;



		sz -= offset;

		needed = (buf_len - sz_copied);

		sz_to_copy = min(sz, needed);



		res = skb_copy_datagram_msg(buf, hlen + offset, m, sz_to_copy);

		if (res)

			goto exit;



		sz_copied += sz_to_copy;



		if (sz_to_copy < sz) {

			if (!(flags & MSG_PEEK))

				TIPC_SKB_CB(buf)->bytes_read =

					offset + sz_to_copy;

			goto exit;

		/* Copy data if msg ok, otherwise return error/partial data */

		if (likely(!err)) {

			offset = skb_cb->bytes_read;

			copy = min_t(int, dlen - offset, buflen - copied);

			rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy);

			if (unlikely(rc))

				break;

			copied += copy;

			offset += copy;

			if (unlikely(offset < dlen)) {

				if (!peek)

					skb_cb->bytes_read = offset;

				break;

			}

		} 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;

			rc = 0;

			if ((err != TIPC_CONN_SHUTDOWN) && !m->msg_control)

				rc = -ECONNRESET;

			if (copied || rc)

				break;

		}



	if (unlikely(flags & MSG_PEEK))

		goto exit;

		if (unlikely(peek))

			break;



	tsk->rcv_unacked += tsk_inc(tsk, hlen + msg_data_sz(msg));

	if (unlikely(tsk->rcv_unacked >= (tsk->rcv_win / 4)))

		tipc_sk_send_ack(tsk);

		tsk_advance_rx_queue(sk);



	/* Loop around if more data is required */

	if ((sz_copied < buf_len) &&	/* didn't get all requested data */

	    (!skb_queue_empty(&sk->sk_receive_queue) ||

	    (sz_copied < target)) &&	/* and more is ready or required */

	    (!err))			/* and haven't reached a FIN */

		goto restart;

		/* Send connection flow control advertisement when applicable */

		tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);

		if (unlikely(tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE))

			tipc_sk_send_ack(tsk);



		/* Exit if all requested data or FIN/error received */

		if (copied == buflen || err)

			break;



	} while (!skb_queue_empty(&sk->sk_receive_queue) || copied < required);

exit:

	release_sock(sk);

	return sz_copied ? sz_copied : res;

	return copied ? copied : rc;

}



/**
@@ -2593,7 +2571,7 @@ static const struct proto_ops stream_ops = { 
	.setsockopt	= tipc_setsockopt,

	.getsockopt	= tipc_getsockopt,

	.sendmsg	= tipc_sendstream,

	.recvmsg	= tipc_recv_stream,

	.recvmsg	= tipc_recvstream,

	.mmap		= sock_no_mmap,

	.sendpage	= sock_no_sendpage

};