[sane-devel] saned/sanei net bug
Hi, On Fri, Oct 15, 2004 at 04:03:04PM +0200, Johannes Berg wrote: somehow saned/the sanei network layer seem to get buffering wrong. I'm afraid that that's intentional. But that's only a guess. For example, I send the following: SANE_NET_INIT SANE_NET_GET_DEVICES SANE_NET_EXIT If I don't wait for the result from SANE_NET_GET_DEVICES before sending the control code for SANE_NET_EXIT, then the SANE_NET_EXIT code is discarded. I think you must really read the result of any RPC before sending the next one. I would assume that somewhere there's a buffering problem and the old buffer is simply dropped when the direction is changed or something. That's done in sanei_w_set_direction(). Set SANE_DEBUG_SANEI_WIRE=255 and you'll even get a warning :-) The following works: (echo -n -e \\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00 ; sleep .1 ; echo -n -e \\00\\00\\x00\\x01 ; sleep 1 ; echo -en \\x00\\x00\\x00\\x0A ) | nc localhost 6566 -q 1 | hd while this doesn't: (echo -n -e \\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00 ; sleep .1 ; echo -n -e \\00\\00\\x00\\x01\\x00\\x00\\x00\\x0A )| nc localhost 6566 -q 1 | hd I think this is extremely counter-intuitive. TCP never guarantees message boundaries, so one wouldn't think that data is explicitly read by the application but then discarded. I guess you are right but I don't really know how to fix that with the current code. One option would be to set the wire to error state (and exit?) when data is discarded. Bye, Henning
[sane-devel] saned/sanei net bug
--=-b6utnWCS15VlnOe3728l Content-Type: text/plain Content-Transfer-Encoding: quoted-printable somehow saned/the sanei network layer seem to get buffering wrong. For example, I send the following: SANE_NET_INIT SANE_NET_GET_DEVICES SANE_NET_EXIT If I don't wait for the result from SANE_NET_GET_DEVICES before sending the control code for SANE_NET_EXIT, then the SANE_NET_EXIT code is discarded. I would assume that somewhere there's a buffering problem and the old buffer is simply dropped when the direction is changed or something. The following works: (echo -n -e \\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00 ; sleep .1 ; echo -n -e \\00\\00\\x00\\x01 ; sleep 1 ; echo -en \\x00\\x00\\x00\\x0A ) | nc localhost 6566 -q 1 | hd while this doesn't: (echo -n -e \\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00\\00 ; sleep .1 ; echo -n -e \\00\\00\\x00\\x01\\x00\\x00\\x00\\x0A )| nc localhost 6566 -q 1 | hd I think this is extremely counter-intuitive. TCP never guarantees message boundaries, so one wouldn't think that data is explicitly read by the application but then discarded. johannes --=-b6utnWCS15VlnOe3728l Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -BEGIN PGP SIGNATURE- Comment: Johannes Berg (SIP Solutions) iQIVAwUAQW/YlaVg1VMiehFYAQLFPg//WIumi+9ZBodt1Ns31jdYGEiJa5z0hvkx RivmO96L+BnL6Ld7Rut2mWx7ftE88yEhWnyzwBj3eFYseXi72n/2E12dpzyKyx+d 4ASxTTeatA/50Prdn2VzaPNe4zccKFpTJdYM7AXYDq3E49XyBrQ0fzin+rCaW0Pd hjhD+bzzVuWxFxSgTsQn8T9z8h43W5BcUdD+a9fxZZMwRapXaFhTiFCTBxNH2zSI yHCa7+Kx8xsGoTjsMt3BiggIn0k0ofNaSzht8BaYR0uelnKDEHrj+JdJgpfOz8OK KcX3gPhsL5JdT4KbmuGyuJSkhZ9gdOGmneBkpX5WB/zUBvS8FxBLM0yyiAmqgzF1 rU9oqAg9psQgotkQY+koeJk8WnOHrstxgHX6rUO6Dbg2EIOv5tNDL/QZ1c/CAQY1 gcPf67was/FbFQ/WDhgyd4C3WdMDnaMrC9WZwIk1klxj6gFz0RqzcQbF97+s+OX0 yAgdl2V3b2SuYW9x9oojshxA6NN+yd3WrIhWxFFlOxkxrdoE1WGlPGwUvQwcVBja KArLPRV4eHM6c8T0RyK6XWfC2aCOZ004EzTtPyOW8ARZZl026gGXNaF/jlw2L1PN UiU8+spF5v4pBiQaiYmmEasGaaHmwHYL6oBI6PV2iMjUnFTz4dYM5EgyP3pSKypW Ph0hiP5wYrc= =L6hJ -END PGP SIGNATURE- --=-b6utnWCS15VlnOe3728l--
