Date: Wed, 10 Sep 1997 21:35:23 -0700 (PDT)
From: Simon Shapiro <Shimon@i-Connect.Net>
To: Terry Lambert <tlambert@primenet.com>
Cc: current@FreeBSD.ORG, nnd@itfs.nsk.su
Subject: Re: PPP - why set CLOCAL for server ('-direct' mode) ?
Message-ID: <XFMail.970910213523.Shimon@i-Connect.Net>
In-Reply-To: <199709110238.TAA23795@usr05.primenet.com>
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Hi Terry Lambert; On 11-Sep-97 you wrote: ... > Without correct use of the partial open hack, and a driver that > supports it, without CLOCAL set, the lack of DCD prevents the > process from communicating with the modem in order to configure > it, since the open hangs until the DCD goes high. I find it highly entertaining that we still have this issue. According to the original CCITT spec, DCD is NOT supposed to go true unless the modem on the other side has handshaked. This is what DCD is (Data Carrier Detect). The solution is very simple; Upon open, you open anyway, ignoring but remembering DCD. If you get a change of state from inactive to active, you change the state, but ignore it. However, if the state transitions from ACTIVE to INACTIVE, you terminate the connection, close the port and generate SIGHUP. This is the simplest and most correct way to handle it. Before you remind me that oh, so many devices know how to fake DCD, I will tell you that I know that. This bug in RS-232C handling is older than some of us. Modem vendors have to connect to Unix boxes, hence, the kludge. --- Sincerely Yours, (Sent on 10-Sep-97, 21:07:16 by XF-Mail) Simon Shapiro Atlas Telecom Senior Architect 14355 SW Allen Blvd., Suite 130 Beaverton OR 97005 Shimon@i-Connect.Net Voice: 503.643.5559, Emergency: 503.799.2313
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