Date: Fri, 8 Jun 2007 18:26:41 +0400 From: Yar Tikhiy <yar@comp.chem.msu.su> To: andre@freebsd.org, net@freebsd.org Subject: A small window-related bug in tcp_input.c? Message-ID: <20070608142641.GA25127@comp.chem.msu.su>
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There is the following code in tcp_input.c (I "underlined" two questionable lines): /* * Process options only when we get SYN/ACK back. The SYN case * for incoming connections is handled in tcp_syncache. * XXX this is traditional behavior, may need to be cleaned up. */ if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) { if ((to.to_flags & TOF_SCALE) && (tp->t_flags & TF_REQ_SCALE)) { tp->t_flags |= TF_RCVD_SCALE; tp->snd_scale = to.to_wscale; tp->snd_wnd = th->th_win << tp->snd_scale; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ tiwin = tp->snd_wnd; } if (to.to_flags & TOF_TS) { tp->t_flags |= TF_RCVD_TSTMP; tp->ts_recent = to.to_tsval; tp->ts_recent_age = ticks; } /* Initial send window, already scaled. */ tp->snd_wnd = th->th_win; ^^^^^^^^^^^^^^^^^^^^^^^^^ if (to.to_flags & TOF_MSS) tcp_mss(tp, to.to_mss); if ((tp->t_flags & TF_SACK_PERMIT) && (to.to_flags & TOF_SACKPERM) == 0) tp->t_flags &= ~TF_SACK_PERMIT; } Is it correct that the scaled value in tp->snd_wnd is later overwritten with the unscaled value from th->th_win? -- Yar
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