Re: bin/58016: wg-userspace(8) requires explicit route setup

[mlelstv%serpens.de@localhost (Michael van Elst)]

The following reply was made to PR bin/58016; it has been noted by GNATS.

From: mlelstv%serpens.de@localhost (Michael van Elst)
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: bin/58016: wg-userspace(8) requires explicit route setup
Date: Sun, 10 Mar 2024 08:44:50 -0000 (UTC)

 riastradh%NetBSD.org@localhost (Taylor R Campbell) writes:
 
 >(Still unclear on why, in the default IFF_POINTOPOINT setting of
 >tun(4), an explicit route is needed only for IPv4 while the system
 >automagically adds the necessary route for IPv6.)
 
 That is 4.4BSD-Lite2:
 
         if (ifp->if_flags & IFF_BROADCAST) {
                 ia->ia_broadaddr.sin_addr.s_addr =
                         htonl(ia->ia_subnet | ~ia->ia_subnetmask);
                 ia->ia_netbroadcast.s_addr =
                         htonl(ia->ia_net | ~ ia->ia_netmask);
         } else if (ifp->if_flags & IFF_LOOPBACK) {
                 ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
                 flags |= RTF_HOST;
         } else if (ifp->if_flags & IFF_POINTOPOINT) {
                 if (ia->ia_dstaddr.sin_family != AF_INET)
                         return (0);
                 flags |= RTF_HOST;
         }
         if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0)
                 ia->ia_flags |= IFA_ROUTE;
 
 
 For POINTOPOINT interfaces, there is a host route to the peer,
 and any network mask is ignored.
 
 The notion of having multiple destinations on a POINTOPOINT
 interface is also a strange one. The original use was for
 a synchronous serial line, not a multi-target tunnel.