diff options
| -rw-r--r-- | src/net/tcp.c | 41 |
1 files changed, 20 insertions, 21 deletions
diff --git a/src/net/tcp.c b/src/net/tcp.c index 234e39a6c..8f2d49ef6 100644 --- a/src/net/tcp.c +++ b/src/net/tcp.c @@ -93,6 +93,8 @@ enum tcp_flags { TCP_XFER_CLOSED = 0x0001, /** TCP timestamps are enabled */ TCP_TS_ENABLED = 0x0002, + /** TCP acknowledgement is pending */ + TCP_ACK_PENDING = 0x0004, }; /** @@ -396,7 +398,6 @@ static size_t tcp_process_queue ( struct tcp_connection *tcp, size_t max_len, * Transmit any outstanding data * * @v tcp TCP connection - * @v force_send Force sending of packet * * Transmits any outstanding data on the connection. * @@ -404,7 +405,7 @@ static size_t tcp_process_queue ( struct tcp_connection *tcp, size_t max_len, * will have been started if necessary, and so the stack will * eventually attempt to retransmit the failed packet. */ -static int tcp_xmit ( struct tcp_connection *tcp, int force_send ) { +static int tcp_xmit ( struct tcp_connection *tcp ) { struct io_buffer *iobuf; struct tcp_header *tcphdr; struct tcp_mss_option *mssopt; @@ -438,7 +439,7 @@ static int tcp_xmit ( struct tcp_connection *tcp, int force_send ) { tcp->snd_sent = seq_len; /* If we have nothing to transmit, stop now */ - if ( ( seq_len == 0 ) && ! force_send ) + if ( ( seq_len == 0 ) && ! ( tcp->flags & TCP_ACK_PENDING ) ) return 0; /* If we are transmitting anything that requires @@ -519,6 +520,9 @@ static int tcp_xmit ( struct tcp_connection *tcp, int force_send ) { return rc; } + /* Clear ACK-pending flag */ + tcp->flags &= ~TCP_ACK_PENDING; + return 0; } @@ -552,7 +556,7 @@ static void tcp_expired ( struct retry_timer *timer, int over ) { tcp_close ( tcp, -ETIMEDOUT ); } else { /* Otherwise, retransmit the packet */ - tcp_xmit ( tcp, 0 ); + tcp_xmit ( tcp ); } } @@ -709,6 +713,7 @@ static void tcp_rx_seq ( struct tcp_connection *tcp, uint32_t seq_len ) { } else { tcp->rcv_win = 0; } + tcp->flags |= TCP_ACK_PENDING; } /** @@ -927,7 +932,6 @@ static int tcp_rx ( struct io_buffer *iobuf, struct tcp_options options; size_t hlen; uint16_t csum; - uint32_t start_seq; uint32_t seq; uint32_t ack; uint32_t win; @@ -967,7 +971,7 @@ static int tcp_rx ( struct io_buffer *iobuf, /* Parse parameters from header and strip header */ tcp = tcp_demux ( ntohs ( tcphdr->dest ) ); - start_seq = seq = ntohl ( tcphdr->seq ); + seq = ntohl ( tcphdr->seq ); ack = ntohl ( tcphdr->ack ); win = ntohs ( tcphdr->win ); flags = tcphdr->flags; @@ -1002,6 +1006,12 @@ static int tcp_rx ( struct io_buffer *iobuf, } } + /* Force an ACK if this packet is out of order */ + if ( ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) && + ( seq != tcp->rcv_ack ) ) { + tcp->flags |= TCP_ACK_PENDING; + } + /* Handle SYN, if present */ if ( flags & TCP_SYN ) { tcp_rx_syn ( tcp, seq, &options ); @@ -1031,19 +1041,8 @@ static int tcp_rx ( struct io_buffer *iobuf, /* Dump out any state change as a result of the received packet */ tcp_dump_state ( tcp ); - /* Send out any pending data. We force sending a reply if either - * - * a) the peer is expecting an ACK (i.e. consumed sequence space), or - * b) either end of the packet was outside the receive window - * - * Case (b) enables us to support TCP keepalives using - * zero-length packets, which we would otherwise ignore. Note - * that for case (b), we need *only* consider zero-length - * packets, since non-zero-length packets will already be - * caught by case (a). - */ - tcp_xmit ( tcp, ( ( start_seq != seq ) || - ( ( seq - tcp->rcv_ack ) > tcp->rcv_win ) ) ); + /* Send out any pending data */ + tcp_xmit ( tcp ); /* If this packet was the last we expect to receive, set up * timer to expire and cause the connection to be freed. @@ -1087,7 +1086,7 @@ static void tcp_xfer_close ( struct tcp_connection *tcp, int rc ) { tcp_close ( tcp, rc ); /* Transmit FIN, if possible */ - tcp_xmit ( tcp, 0 ); + tcp_xmit ( tcp ); } /** @@ -1125,7 +1124,7 @@ static int tcp_xfer_deliver ( struct tcp_connection *tcp, list_add_tail ( &iobuf->list, &tcp->queue ); /* Transmit data, if possible */ - tcp_xmit ( tcp, 0 ); + tcp_xmit ( tcp ); return 0; } |