From e9f8b10101c6da3ab000a2fb17162374c9bd2c69 Mon Sep 17 00:00:00 2001 From: Jon Paul Maloy Date: Tue, 2 May 2017 18:16:53 +0200 Subject: [PATCH 1/2] tipc: refactor function tipc_sk_recvmsg() We try to make this function more readable by improving variable names and comments, plus some minor changes to the logics. Reviewed-by: Parthasarathy Bhuvaragan Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/socket.c | 121 +++++++++++++++++++++------------------------- 1 file changed, 56 insertions(+), 65 deletions(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 8a4e9fe5f9eb..3855bfd1fb1b 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -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. @@ -1298,89 +1299,79 @@ 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) - 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)) { - tsk_advance_rx_queue(sk); - goto restart; - } - - /* 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) - 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; - } - res = skb_copy_datagram_msg(buf, hlen, m, sz); - 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; - res = sz; - } else { - if (is_connectionless || err == TIPC_CONN_SHUTDOWN || - m->msg_control) - res = 0; - else - res = -ECONNRESET; - } + 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); + } while (1); + /* 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 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; + rc = skb_copy_datagram_msg(skb, hlen, m, copy); + } else { + 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; } /** From ec8a09fbbeff252c80daf62c7a78342003dddf9c Mon Sep 17 00:00:00 2001 From: Jon Paul Maloy Date: Tue, 2 May 2017 18:16:54 +0200 Subject: [PATCH 2/2] tipc: refactor function tipc_sk_recv_stream() We try to make this function more readable by improving variable names and comments, using more stack variables, and doing some smaller changes to the logics. We also rename the function to make it consistent with naming conventions used elsewhere in the code. Reviewed-by: Parthasarathy Bhuvaragan Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/socket.c | 159 +++++++++++++++++++++------------------------- 1 file changed, 73 insertions(+), 86 deletions(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 3855bfd1fb1b..7e45ef938c18 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1375,9 +1375,9 @@ exit: } /** - * 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 @@ -1385,111 +1385,98 @@ exit: * * 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); + 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); -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)) { - tsk_advance_rx_queue(sk); - goto restart; - } - - /* 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; - } - - /* 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; + /* Discard any empty non-errored (SYN-) message */ + if (unlikely(!dlen && !err)) { + tsk_advance_rx_queue(sk); + continue; } - } 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; - } + /* 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; + } - if (unlikely(flags & MSG_PEEK)) - 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 { + rc = 0; + if ((err != TIPC_CONN_SHUTDOWN) && !m->msg_control) + rc = -ECONNRESET; + if (copied || rc) + 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); + if (unlikely(peek)) + break; - /* 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; + tsk_advance_rx_queue(sk); + /* 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; } /** @@ -2584,7 +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 };