Author: rscheff Date: Thu May 21 19:41:25 2020 New Revision: 361340 URL: https://svnweb.freebsd.org/changeset/base/361340
Log: MFC r360479: Prevent premature shrinking of the scaled receive window which can cause a TCP client to use invalid or stale TCP sequence numbers for ACK packets. Packets with old sequence numbers are ignored and not used to update the send window size. This might cause the TCP session to hang indefinitely under some circumstances. Reported by: Cui Cheng Reviewed by: tuexen (mentor), rgrimes (mentor, blanket) Approved by: tuexen (mentor), rgrimes (mentor, blanket) MFC after: 3 weeks Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D24515 Modified: stable/12/sys/netinet/tcp_output.c stable/12/sys/netinet/tcp_stacks/rack.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/netinet/tcp_output.c ============================================================================== --- stable/12/sys/netinet/tcp_output.c Thu May 21 18:50:05 2020 (r361339) +++ stable/12/sys/netinet/tcp_output.c Thu May 21 19:41:25 2020 (r361340) @@ -1206,8 +1206,11 @@ send: if (flags & TH_SYN) th->th_win = htons((u_short) (min(sbspace(&so->so_rcv), TCP_MAXWIN))); - else + else { + /* Avoid shrinking window with window scaling. */ + recwin = roundup2(recwin, 1 << tp->rcv_scale); th->th_win = htons((u_short)(recwin >> tp->rcv_scale)); + } /* * Adjust the RXWIN0SENT flag - indicate that we have advertised Modified: stable/12/sys/netinet/tcp_stacks/rack.c ============================================================================== --- stable/12/sys/netinet/tcp_stacks/rack.c Thu May 21 18:50:05 2020 (r361339) +++ stable/12/sys/netinet/tcp_stacks/rack.c Thu May 21 19:41:25 2020 (r361340) @@ -8355,8 +8355,11 @@ send: if (flags & TH_SYN) th->th_win = htons((u_short) (min(sbspace(&so->so_rcv), TCP_MAXWIN))); - else + else { + /* Avoid shrinking window with window scaling. */ + recwin = roundup2(recwin, 1 << tp->rcv_scale); th->th_win = htons((u_short)(recwin >> tp->rcv_scale)); + } /* * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0 * window. This may cause the remote transmitter to stall. This _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
