On Wed, Jan 18, 2017 at 2:57 AM, Julian Cordes <julian.cordes@xxxxxxxxx> wrote: > 2017-01-17 19:49 GMT+01:00 Xin Long <lucien.xin@xxxxxxxxx>: >> On Tue, Jan 17, 2017 at 9:13 PM, Julian Cordes <julian.cordes@xxxxxxxxx> wrote: >>> When fragmented ordered user messages are sent to the linux kernel user >>> messages with inconsistent stream sequence numbers are accepted and >>> delivered to the application. Take for example an look at the following test case: >>> https://github.com/nplab/PR_SCTP_Testsuite/blob/master/forward-tsn/error-cases/packet-loss/ordered/ordered-packet-loss-2.pkt >>> >>> Here I first inject two DATA-Chunks with sid/ssn 1/1, 2/1 into the >>> kernel with packetdrill: >>> line 67: +0.0 < sctp: DATA[flgs=E, len=1016, tsn=2, sid=1, ssn=1, >>> ppid=0] >>> line 69: +0.1 < sctp: DATA[flgs=E, len=1016, tsn=4, sid=2, ssn=1, >>> ppid=0] >>> >>> After 0.1 seconds i then inject an FORWARD-TSN with cum_tsn=2 bundled >>> with an DATA-Chunk that looks like this: >>> DATA[flgs=B, len=1016, tsn=3, sid=2, ssn=0, ppid=0] >>> >>> This "looks" like the first segment of the user message where already a >>> fragment (tsn=4) was received. But the ssn-values are not consistent. >>> The DATA-Chunk with tsn=3 has ssn=0 and the ssn=1 therefore they should >>> be ignored by the IUT and not be delivered to the userland application when >>> calling sctp_recvmsg. Unfortunatly the linux kernel implementation does >>> currently deliver these inconsistent user messages. >> sorry, I may misunderstand you. >> >> after FORWARD-TSN, "DATA[flgs=E, len=1016, tsn=2, sid=1, ssn=1" >> should be received, then only "sctp: DATA[flgs=E, len=1016, tsn=4, >> sid=2, ssn=1" is in the queue, then "DATA[flgs=B, len=1016, tsn=3, >> sid=2, ssn=0, ppid=0]" is processed, these two chunks (tsn=3 and >> tsn=4) should be recvmsg, as their sid are the same and ssn are >> consistent (ssn=0 and ssn=1). >> and your sctp_recvmsg is after above, so it should be right. >> >> did I miss something? >> >> > Shouldnt the ssn be 0 for both DATA-Chunks with sid=2, because they > consistent to the same first fragmented user message of stream with > sid=2? ahh, got you now, will look into it tomorrow, thanks. >>> >>> There are many test-cases that all reproduce this >>> issue. Just take a look at the README at >>> https://github.com/nplab/PR_SCTP_Testsuite/tree/master/forward-tsn/error-cases/packet-loss/ordered. -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
