Comment 0 for bug 1831775

Investigating an issue for CTDB (LP: #722201), after suggesting a fix on ss syntax to CTDB upstream project, we discovered that "ss" seems to be broken in Ubuntu since Ubuntu Cosmic:

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# Debian Sid

inaddy@workstation:~$ ss -tn state established "( src [172.16.17.2] || src [172.16.17.3] )" "( sport == :2049 )"
Recv-Q Send-Q Local Address:Port Peer Address:Port

# Ubuntu Ubuntu 16.04 LTS (Xenial Xerus)

(c)inaddy@xenial:~$ ss -tn state established "( src [172.16.17.2] || src [172.16.17.3] )" "( sport == :2049 )"
Recv-Q Send-Q Local Address:Port Peer Address:Port

# Ubuntu 18.04 LTS (Bionic Beaver)

(c)inaddy@bionic:~$ ss -tn state established "( src [172.16.17.2] || src [172.16.17.3] )" "( sport == :2049 )"
Recv-Q Send-Q Local Address:Port Peer Address:Port

# Ubuntu 18.10 (Cosmic Cuttlefish)

(c)inaddy@cosmic:~$ ss -tn state established "( src [172.16.17.2] || src [172.16.17.3] )" "( sport == :2049 )"
ss: bison bellows (while parsing filter): "syntax error!" Sorry.
Usage: ss [ OPTIONS ]
       ss [ OPTIONS ] [ FILTER ]
   -h, --help this message

# Ubuntu 19.04 (Disco Dingo)

(c)inaddy@disco:~$ ss -tn state established "( src [172.16.17.2] || src [172.16.17.3] )" "( sport == :2049 )"
ss: bison bellows (while parsing filter): "syntax error!" Sorry.
Usage: ss [ OPTIONS ]
       ss [ OPTIONS ] [ FILTER ]

# Ubuntu 19.10 (Eoan Ermine)

(c)inaddy@eoan:~$ ss -tn state established "( src [172.16.17.2] || src [172.16.17.3] )" "( sport == :2049 )"
ss: bison bellows (while parsing filter): "syntax error!" Sorry.
Usage: ss [ OPTIONS ]
       ss [ OPTIONS ] [ FILTER ]

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I have generated a pkg using upstream iproute2 source code and it does not suffer the issue. I have generated a package using Ubuntu cosmic source package, without debian/patches/*, and verified the issue still persists (not being introduced by any of our packages, and being present if vanilla upstream version used in Cosmic).