Issue in bgpd.

[Venkateshwaran R]

Dear All

Please find below issue that i found in bgpd.

Package details
===========
Zebra Version - zebra-0.95a
Linux version - 2.6.9-1.667(FC3)
zebra daemon  - bgpd

RFC Reference
===========
RFC 4271, Page no 26 , Section5.1.2 bullet 1)  describes.
 1) if the first path segment of the AS_PATH is of type
            AS_SEQUENCE, the local system prepends its own AS number as
            the last element of the sequence (put it in the leftmost
            position with respect to the position of octets in the
            protocol message).  If the act of prepending will cause an
            overflow in the AS_PATH segment (i.e., more than 255 ASes),
            it SHOULD prepend a new segment of type AS_SEQUENCE and
            prepend its own AS number to this new segment.


To create this scenario i sent an UPDATE message with 255 ASes in AS_PATH 
attribute.

bgpd Behavior
============
"bgpd" adds its AS no as 256th position[ ie., doesn't introduce new segment due 
to overflow in the AS_PATH segment ]and
advertise the UPDATE message with the path segment length value =0[bgpd 
considers path segment length value as
256, but the variable may declared with one byte ie., unsigned char].

Hope this clarifies you. 
Please excuse me if any thing wrong in my side and explain me what i did and 
how to get this.


Regards
Venkat



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