February 2010 - Darwin-kernel

Re: SCTP on mac
by Michael Tüxen 04 Feb '10

04 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Feb 4, 2010, at 12:14 AM, Godfrey van der Linden wrote: > G'day, Michael, > > It seems that SCTP can do what I want it seems to be a bit tricky to install. I need to create an installer... I did this for the versions for Tiger and Leopard. > > I'm actually pretty good with the Darwin Kernel (though with an IOKit bent). Can you send me the source code to the snow leopard SCTP NKEs I'll send you a link in a separate mail... > > Also I'm sort of curious, what is the SCTPSupport kext for? Are you working around some kext issue? Just exporting symbols that the NKE needs. Unfortunately, it is not possible to implement a transport protocol which makes use of the socket layer by using the API provided by Apple. So I compile the kernel, when Apple releases the darwin source code and build the SCTPSupport kext. Best regards Michael > > Cheers > > Godfrey > > _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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SCTP on mac
by Godfrey van der Linden 03 Feb '10

03 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com G'day, Michael, It seems that SCTP can do what I want it seems to be a bit tricky to install. I'm actually pretty good with the Darwin Kernel (though with an IOKit bent). Can you send me the source code to the snow leopard SCTP NKEs Also I'm sort of curious, what is the SCTPSupport kext for? Are you working around some kext issue? Cheers Godfrey _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: connected SOCK_DGRAM disconnects
by Michael Tüxen 02 Feb '10

02 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Feb 2, 2010, at 7:49 AM, Godfrey van der Linden wrote: > > On 2010-02-02, at 4:32 PM, Michael Smith wrote: > >> >> On Feb 1, 2010, at 6:40 PM, Godfrey van der Linden wrote: >> >>> I'm trying something a bit different for performance testing and have tripped over a problem that I just haven't been able to solve. Maybe you netheads out there can enlighten me. >>> >>> I have a pair of threads each of which have independent AF_UNIX, SOCK_DGRAM sockets. >>> >>> The client knows the servers AF_UNIX address and connect()s the client socket to the server before sending the first message. >>> >>> The server on recvfrom()ing the first message then connect()s the server's socket to the received client's address. Then falls into a simple mirror loop, that is send a reply, block in recv(). >>> >>> After a few messages the client, closes its socket. >>> >>> Q> Shouldn't the server's blocked recv() call be aborted with an ECONNRESET error, when the client's socket is closed? >> >> No. ECONNRESET is the tunnel for the TCP RST behaviour. There is no analog for datagram sockets. >> > Yeah, I came to that realisation, I saw the error returned once during my testing and it never turned up again after moving the code around a bit. > > Pity, what I'd really love is if we had an implementation of SOCK_SEQPACKET, in the UNIX and INETx protocol families. SCTP provides a reliable datagram service and uses SOCK_SEQPACKET... Best regards Michael > >>> I know that this is an unusual usage of DGRAM sockets, but I eventually need some sort of control on the packet size when it goes through my instrumented network driver. >> >> >> Why not just advertise an appropriate MSS and let the network stack handle the rest for you? >> > Sounds interesting, I'm not really a network programmer so all of my knowledge is just what you can glean from Stevens. What is MSS? > > My research problem: > > I wish to build an energy consumption model of a heavily instrumented IOEthernetController subclass. > > To determine the per-byte and per-packet energy cost of sending and receiving packets, I'll need to finely control the frame sizes as they go on the bus to calibration the energy model. I don't think there is any sensible way of controlling the TCP/IP frame on a per packet basis, hence the UDP/IP decision. I'd really, really love a connection oriented per packet socket but there doesn't seem to be such an option. > >> = Mike > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-kernel/michael.tuexen%40lurch… > > This email sent to michael.tuexen(a)lurchi.franken.de > _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: connected SOCK_DGRAM disconnects
by Robert Bell 02 Feb '10

02 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Maximum Segment Size. -R Le 1 févr. 2010 à 22:49, Godfrey van der Linden a écrit : > > On 2010-02-02, at 4:32 PM, Michael Smith wrote: > >> >> On Feb 1, 2010, at 6:40 PM, Godfrey van der Linden wrote: >> >>> I'm trying something a bit different for performance testing and have tripped over a problem that I just haven't been able to solve. Maybe you netheads out there can enlighten me. >>> >>> I have a pair of threads each of which have independent AF_UNIX, SOCK_DGRAM sockets. >>> >>> The client knows the servers AF_UNIX address and connect()s the client socket to the server before sending the first message. >>> >>> The server on recvfrom()ing the first message then connect()s the server's socket to the received client's address. Then falls into a simple mirror loop, that is send a reply, block in recv(). >>> >>> After a few messages the client, closes its socket. >>> >>> Q> Shouldn't the server's blocked recv() call be aborted with an ECONNRESET error, when the client's socket is closed? >> >> No. ECONNRESET is the tunnel for the TCP RST behaviour. There is no analog for datagram sockets. >> > Yeah, I came to that realisation, I saw the error returned once during my testing and it never turned up again after moving the code around a bit. > > Pity, what I'd really love is if we had an implementation of SOCK_SEQPACKET, in the UNIX and INETx protocol families. > >>> I know that this is an unusual usage of DGRAM sockets, but I eventually need some sort of control on the packet size when it goes through my instrumented network driver. >> >> >> Why not just advertise an appropriate MSS and let the network stack handle the rest for you? >> > Sounds interesting, I'm not really a network programmer so all of my knowledge is just what you can glean from Stevens. What is MSS? > > My research problem: > > I wish to build an energy consumption model of a heavily instrumented IOEthernetController subclass. > > To determine the per-byte and per-packet energy cost of sending and receiving packets, I'll need to finely control the frame sizes as they go on the bus to calibration the energy model. I don't think there is any sensible way of controlling the TCP/IP frame on a per packet basis, hence the UDP/IP decision. I'd really, really love a connection oriented per packet socket but there doesn't seem to be such an option. > >> = Mike > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-kernel/robert.m.a.bell%40mac.… > > This email sent to robert.m.a.bell(a)mac.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: connected SOCK_DGRAM disconnects
by Godfrey van der Linden 02 Feb '10

02 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 2010-02-02, at 4:32 PM, Michael Smith wrote: > > On Feb 1, 2010, at 6:40 PM, Godfrey van der Linden wrote: > >> I'm trying something a bit different for performance testing and have tripped over a problem that I just haven't been able to solve. Maybe you netheads out there can enlighten me. >> >> I have a pair of threads each of which have independent AF_UNIX, SOCK_DGRAM sockets. >> >> The client knows the servers AF_UNIX address and connect()s the client socket to the server before sending the first message. >> >> The server on recvfrom()ing the first message then connect()s the server's socket to the received client's address. Then falls into a simple mirror loop, that is send a reply, block in recv(). >> >> After a few messages the client, closes its socket. >> >> Q> Shouldn't the server's blocked recv() call be aborted with an ECONNRESET error, when the client's socket is closed? > > No. ECONNRESET is the tunnel for the TCP RST behaviour. There is no analog for datagram sockets. > Yeah, I came to that realisation, I saw the error returned once during my testing and it never turned up again after moving the code around a bit. Pity, what I'd really love is if we had an implementation of SOCK_SEQPACKET, in the UNIX and INETx protocol families. >> I know that this is an unusual usage of DGRAM sockets, but I eventually need some sort of control on the packet size when it goes through my instrumented network driver. > > > Why not just advertise an appropriate MSS and let the network stack handle the rest for you? > Sounds interesting, I'm not really a network programmer so all of my knowledge is just what you can glean from Stevens. What is MSS? My research problem: I wish to build an energy consumption model of a heavily instrumented IOEthernetController subclass. To determine the per-byte and per-packet energy cost of sending and receiving packets, I'll need to finely control the frame sizes as they go on the bus to calibration the energy model. I don't think there is any sensible way of controlling the TCP/IP frame on a per packet basis, hence the UDP/IP decision. I'd really, really love a connection oriented per packet socket but there doesn't seem to be such an option. > = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: connected SOCK_DGRAM disconnects
by Justin C. Walker 02 Feb '10

02 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi, Godfrey, On Feb 1, 2010, at 18:40 , Godfrey van der Linden wrote: After a few messages the client, closes its socket. Someone with more current knowledge may be able to shed more light. Justin -- Justin C. Walker, Curmudgeon at Large Institute for the Absorption of Federal Funds ----------- I'm beginning to like the cut of his jibberish. ----------- _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I'm trying something a bit different for performance testing and have tripped over a problem that I just haven't been able to solve. Maybe you netheads out there can enlighten me. I have a pair of threads each of which have independent AF_UNIX, SOCK_DGRAM sockets. The client knows the servers AF_UNIX address and connect()s the client socket to the server before sending the first message. The server on recvfrom()ing the first message then connect()s the server's socket to the received client's address. Then falls into a simple mirror loop, that is send a reply, block in recv(). Q> Shouldn't the server's blocked recv() call be aborted with an ECONNRESET error, when the client's socket is closed? This is just a guess, since it's been an eon or so since I delved into the code behind the API, but I believe that, for SOCK_DGRAM, the 'connect' function is used essentially to store destination address information (so you don't have to provide it with every datagram). I'm pretty sure that SOCK_DGRAM does not come with real 'connection' semantics (so in particular, there's no way for one end to tell the other that the local user has closed/disconnected). It's certainly the case for UDP, but for AF_UNIX, I'm not so sure. This email sent to site_archiver(a)lists.apple.com

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connected SOCK_DGRAM disconnects
by Godfrey van der Linden 02 Feb '10

02 Feb '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com G'day, All. I'm trying something a bit different for performance testing and have tripped over a problem that I just haven't been able to solve. Maybe you netheads out there can enlighten me. I have a pair of threads each of which have independent AF_UNIX, SOCK_DGRAM sockets. The client knows the servers AF_UNIX address and connect()s the client socket to the server before sending the first message. The server on recvfrom()ing the first message then connect()s the server's socket to the received client's address. Then falls into a simple mirror loop, that is send a reply, block in recv(). After a few messages the client, closes its socket. Q> Shouldn't the server's blocked recv() call be aborted with an ECONNRESET error, when the client's socket is closed? I know that this is an unusual usage of DGRAM sockets, but I eventually need some sort of control on the packet size when it goes through my instrumented network driver. Godfrey _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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