cc'ing linux-sctp. On Sat, Apr 20, 2019 at 4:24 PM Xin Long <lucien.xin@xxxxxxxxx> wrote: > > Hi, Michael, > > I'm trying to implement SCTP NAT > (https://tools.ietf.org/html/draft-ietf-tsvwg-natsupp-12) on linux, > but got some questions: > > 1. > +-------+ > /--------| NAT 1 |--------\ /--\/--\ > +------+ / +-------+ \ / \ +--------+ > | Host |=== ====| Internet |===| Host B | > | A | \ +-------+ / \ / +--------+ > +------+ \--------| NAT 2 |--------/ \--/\--/ > +-------+ > > In this topo, after 4 shake-hands and asconf: > > +---------+--------+----------+--------+-----------+ > NAT 1 | Int | Int | Ext | Ext | Priv | > | VTag | Port | VTag | Port | Addr | > +---------+--------+----------+--------+-----------+ > | 1234 | 1 | 5678 | 2 | 10.0.0.1 | > +---------+--------+----------+--------+-----------+ > > +---------+--------+----------+--------+-----------+ > NAT 2 | Int | Int | Ext | Ext | Priv | > | VTag | Port | VTag | Port | Addr | > +---------+--------+----------+--------+-----------+ > | 1234 | 1 | 5678 | 2 | 10.1.0.1 | > +---------+--------+----------+--------+-----------+ > > Now there are 1 entry on nat1 and 1 entry on nat2. If the connection is > shutdown via nat1, the entry on nat1 will be deleted, right? What about > the entry on nat2, when can it be deleted? > > 2. > /--\/--\ > +--------+ +-----+ / \ +--------+ > | Host A | <----------> | NAT | <----> | Internet | <----> | Host B | > +--------+ +-----+ \ / +--------+ > \--/\--/ > > In this topo, if both paths with saddr 10.0.0.1 and 10.1.0.1 go through > NAT, will there be 2 entries created on this NAT after 4 shake-hands and > asconf like: > > +---------+--------+----------+--------+-----------+ > NAT | Int | Int | Ext | Ext | Priv | > | VTag | Port | VTag | Port | Addr | > +---------+--------+----------+--------+-----------+ > | 1234 | 1 | 5678 | 2 | 10.0.0.1 | > +---------+--------+----------+--------+-----------+ > | 1234 | 1 | 5678 | 2 | 10.1.0.1 | > +---------+--------+----------+--------+-----------+ > > or it will be handled as "Internal Port Number and Verification Tag > Collisions"? > > 3. > For multipath, each entry for one path should maintain a 'state', like > closed, established, cookie-echo etc, right? If they belong to a same > association, especially when they're on different nats, how do we keep > each entry's state consistent? or they don't have to be consistent? > > Thanks.
