On Jan 13 00:36, Mark Geisert wrote: > This report is based on a series of recent list emails with Subject: lines > "RPC clnt_create() adress already in use" which date back to last September > but are unfortunately not chained together... They contain a discussion > I've been having with OP Raimund Paulus. > > I believe I've distilled the issue(s) down as far as I can. A > self-contained STC is included at the end of this email. > > On the latest 64-bit Cygwin, running the STC shows: > > ~ netstat -an|grep :111 > TCP 0.0.0.0:111 0.0.0.0:0 LISTENING > TCP [::]:111 [::]:0 LISTENING > UDP 0.0.0.0:111 *:* > UDP [::]:111 *:* > > ~ ./bindtest > 1st socket is 3 > 1st bind OK > 1st connect OK > 2nd socket is 3 > 2nd bind OK > 2nd connect: Address already in use > > ~ ./bindtest > 1st socket is 3 > 1st bind OK > 1st connect: Address already in use > > On Fedora 27, running the same STC shows: > > [mark@lux ~]$ netstat -an|grep :111 > tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN > tcp6 0 0 :::111 :::* LISTEN > udp 0 0 0.0.0.0:111 0.0.0.0:* > udp6 0 0 :::111 :::* > [mark@lux ~]$ ./bindtest > 1st socket is 3 > 1st bind OK > 1st connect OK > 2nd socket is 3 > 2nd bind OK > 2nd connect OK
I can't reproduce this: $ uname -sr Linux 4.14.13-300.fc27.x86_64 $ netstat -an|grep :111 tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN tcp6 0 0 :::111 :::* LISTEN udp 0 0 0.0.0.0:111 0.0.0.0:* udp6 0 0 :::111 :::* $ ./bindtest 1st socket is 3 1st bind OK 1st connect OK 2nd socket is 3 2nd bind OK 2nd connect: Cannot assign requested address I tried this a couple of times even as root, just to be sure, but the result is invariable "2nd connect: Cannot assign requested address". The error message is different from Cygwin, but the overall behaviour is the same for me, and it matches the comment I wrote in cygwin_setsockopt back in 2009 and 2011. I'm very puzzled that it works for you. As I wrote in my comment, a complete duplicate of a local TCP address is not allowed, regardless of SO_REUSEADDR. If I may quote Mr. Network himself, the late W. R. Stevens, "UNIX Network Programming, Networking APIs: Sockets and XTI", Volume 1, 2nd Edition. Section 7.5: "With TCP we are never able to start multiple servers that bind the same IP address and the same port: a 'complete duplicate binding'. That is, we cannot start one server that binds 198.69.10.2 port 80 and start another that also binds 198.69.10.2 port 80, even if we set the SO_REUSEADDR soocket option for the second server." Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
signature.asc
Description: PGP signature
