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[tcp] Update ts_recent whenever window is advanced 

Commit 3f442d3 ("[tcp] Record ts_recent on first received packet")
failed to achieve its stated intention.

Fix this (and reduce the code size) by moving the ts_recent update to
tcp_rx_seq().  This is the code responsible for advancing the window,
called by both tcp_rx_syn() and tcp_rx_data(), and so the window check
is now redundant.

Reported-by: Frank Weed <zorbustheknight@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/5/head
Michael Brown 2011-04-03 00:37:27 +01:00
parent 06f1878fb8
commit c4369eb6c2
1 changed files with 22 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/net/tcp.c
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@ -74,7 +74,13 @@ struct tcp_connection {
* Equivalent to RCV.WND in RFC 793 terminology.
*/
uint32_t rcv_win;
/** Most recent received timestamp
/** Received timestamp value
*
* Updated when a packet is received; copied to ts_recent when
* the window is advanced.
*/
uint32_t ts_val;
/** Most recent received timestamp that advanced the window
*
* Equivalent to TS.Recent in RFC 1323 terminology.
*/
@ -740,12 +746,24 @@ static void tcp_rx_opts ( struct tcp_connection *tcp, const void *data,
* @v seq_len Sequence space length to consume
*/
static void tcp_rx_seq ( struct tcp_connection *tcp, uint32_t seq_len ) {
/* Sanity check */
assert ( seq_len > 0 );
/* Update acknowledgement number */
tcp->rcv_ack += seq_len;
/* Update window */
if ( tcp->rcv_win > seq_len ) {
tcp->rcv_win -= seq_len;
} else {
tcp->rcv_win = 0;
}
/* Update timestamp */
tcp->ts_recent = tcp->ts_val;
/* Mark ACK as pending */
tcp->flags |= TCP_ACK_PENDING;
}
@ -1060,7 +1078,6 @@ 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;
@ -1100,12 +1117,14 @@ static int tcp_rx ( struct io_buffer *iobuf,
/* Parse parameters from header and strip header */
tcp = tcp_demux ( ntohs ( tcphdr->dest ) );
seq = start_seq = ntohl ( tcphdr->seq );
seq = ntohl ( tcphdr->seq );
ack = ntohl ( tcphdr->ack );
win = ntohs ( tcphdr->win );
flags = tcphdr->flags;
tcp_rx_opts ( tcp, ( ( ( void * ) tcphdr ) + sizeof ( *tcphdr ) ),
( hlen - sizeof ( *tcphdr ) ), &options );
if ( options.tsopt )
tcp->ts_val = ntohl ( options.tsopt->tsval );
iob_pull ( iobuf, hlen );
len = iob_len ( iobuf );
seq_len = ( len + ( ( flags & TCP_SYN ) ? 1 : 0 ) +
@ -1152,12 +1171,6 @@ static int tcp_rx ( struct io_buffer *iobuf,
goto discard;
}
/* Update timestamp, if applicable */
if ( options.tsopt &&
tcp_in_window ( tcp->rcv_ack, start_seq, seq_len ) ) {
tcp->ts_recent = ntohl ( options.tsopt->tsval );
}
/* Enqueue received data */
tcp_rx_enqueue ( tcp, seq, flags, iob_disown ( iobuf ) );