> On 18. Jun 2021, at 18:35, Xin Long <lucien.xin@xxxxxxxxx> wrote: > > On Thu, Jun 17, 2021 at 4:40 PM Sérgio <surkamp@xxxxxxxxx> wrote: >> >> Hello, >> >> I am troubleshooting a deployment with SCTP and eventually found that >> the client has configured the equipment using addresses within the >> RFC2544 annex C.2.2 test network (198.18.0.0/15). >> >> Although I think the deployment network may be changed to use another >> address space in order to "solve" the issue, the restriction >> enforcement on the SCTP kernel driver (implemented by function >> sctp_v4_addr_valid -- net/sctp/protocol.c -- in expansion of >> IS_IPV4_UNUSABLE_ADDRESS -- include/net/sctp/consntans.h) seems odd to >> me, because the address is a valid unicast IPv4 address and should be >> acceptable as per RFC4960 clause 8.4: >> >> The receiver of an OOTB packet MUST do the following: >> >> 1) If the OOTB packet is to or from a non-unicast address, a >> receiver SHOULD silently discard the packet. Otherwise, >> >> The source code states that this restriction came from >> draft-stewart-tsvwg-sctp-ipv4, which is true, and the sysctl >> net.sctp.addr_scope_policy is documented in ip-sysctl.txt as a switch >> for the desired draft behavior, but changing the sysctl value has no >> effect because IS_IPV4_UNUSABLE_ADDRESS macro expansion has no >> verification of any sysctl configuration nor the sctp_v4_addr_valid. >> >> The draft-stewart-tsvwg-sctp-ipv4 enforcement seems like a bug or I am >> missing something? >> > There must be a reason for not using 198.18.0.0/24 in SCTP, as in > > https://datatracker.ietf.org/doc/html/draft-stewart-tsvwg-sctp-ipv4-00#section-3.1 > > [1] IANA, I., "Special-Use IPv4 Addresses", draft-iana-special-ipv4- > 03 (work in progress), April 2002. > > https://datatracker.ietf.org/doc/html/draft-iana-special-ipv4-03 I think not allowing it at all is wrong. https://datatracker.ietf.org/doc/html/rfc6890 states that it is not global. So maybe level 3 would be more appropriate. Please note, the ID was never published as an RFC, so there might be more errors... Best regards Michael
