Re: control characters in BGP shutdown communication(RFC 9003) messages and NETCONF

[Yang Yu via NANOG <nanog () lists nanog org>]

On Sun, Sep 7, 2025 at 5:26 AM Martin Tonusoo via NANOG
<nanog () lists nanog org> wrote:
> Hi.
>
> Meta(AS 32934) recently sent a cease NOTIFICATION message to its
> neighbors on AMS-IX and Piter-IX which had a "<0b>maintenance" string
> on the RFC 9003 "Shutdown Communication" field. In other words, the
> "Shutdown Communication" field contained "0b 6d 61 69 6e 74 65 6e 61
> 6e 63 65". At least on Junos(tested with versions 21.4R3-S3.4,
> 23.2R2-S4.5 and 25.2R1.9), calling the "get-bgp-summary-information"
> or "get-bgp-neighbor-information" RPCs using NETCONF returns the
> string containing the control character and this in turn means that
> libraries parsing the XML fail as 0x0b(vertical tab) is not in the
> allowed character range of XML 1.0:
> https://www.w3.org/TR/xml/#charsets

The admin shutdown message has been removed due to this exact parsing
issue (the BGP NOTIFICATION message is correctly formatted over the
wire). If you use RPCs like `get-bgp-neighbor-information` for the
last shutdown reason, the parsing error might linger for some time.
Apologies for the trouble.


Yang
_______________________________________________
NANOG mailing list 
https://lists.nanog.org/archives/list/nanog () lists nanog org/message/UD7HMY6UCRW45WWQLPAB4BNIWCOGUVYX/