netdev - Why we need add :: at the last when encap seg6 with inline mode?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <ZJqPg7Ck8ulDp2f+@Laptop-X1>
Date: Tue, 27 Jun 2023 15:28:03 +0800
From: Hangbin Liu <liuhangbin@...il.com>
To: David Lebrun <dlebrun@...gle.com>
Cc: Andrea Mayer <andrea.mayer@...roma2.it>, netdev@...r.kernel.org
Subject: Why we need add :: at the last when encap seg6 with inline mode?

Hi David,

When I tried encap seg6 inline mode via iproute, I saw it added a :: address
at the last.

# ip -6 route add 1234::1234 encap seg6 mode inline segs 1::1 dev dum1
# ip -6 route show dev dum1
1234::1234  encap seg6 mode inline segs 2 [ 1::1 :: ] metric 1024 pref medium

In the iproute2 code

```
static struct ipv6_sr_hdr *parse_srh(char *segbuf, int hmac, bool encap)
{
        ...
        if (!encap)
                nsegs++;
        ...
```

So is there any reason we add this?

Thanks
Hangbin