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| author | Hiroki Shirokura <slank.dev@gmail.com> | 2020-02-04 00:11:29 +0000 |
|---|---|---|
| committer | Hiroki Shirokura <slank.dev@gmail.com> | 2020-02-14 00:13:43 +0000 |
| commit | e5d4cda0a7bcc0c0ccbd7d6c11dfa63dfa43ff1c (patch) | |
| tree | 98080418ace01dafecdbb3ed0e92b9aac2190698 | |
| parent | 38774fc5e6b8da326bbe3700d7d54498aedb154a (diff) | |
bgpd: fix Prefix-SID parsing failure case
Prefix-SID path attribute Label-index TLV (type-1) is
used by SR-MPLS. And Label-index TLV MUST ignored
if that path attribute is append on non-Labeled-unicast
UPDATE message described on [ref1].
There is a problem case exist arround this implementation.
This commit fix that.
Before this commit,
unfortunally, setting Label-Index value is skipped at somecases.
because, Label-Index TLV implementation check the AFI/SAFI pair.
by mp_update variable that is set by bgp_mp_reach_parse function.
if MP_REACH_NLRI is present after PREFIX_SID, bgp_attr_psid_sub
function can't understand AFI/SAFI pair. and the order of each
path attributes is never no-deterministic thing for receiver.[ref2]
In this commit,
I re-located checking code of AFI/SAFI pair after path-attr loop.
[ref1](https://tools.ietf.org/html/draft-ietf-idr-bgp-prefix-sid-27#section-3.2)
> The Originator SRGB TLV may only appear in a BGP Prefix-SID attribute
> attached to IPv4/IPv6 Labeled Unicast prefixes ([RFC8277]). It MUST
> be ignored when received for other BGP AFI/SAFI combinations.
[ref2](https://tools.ietf.org/html/rfc4271#section-5)
> The sender of an UPDATE message SHOULD order path attributes within
> the UPDATE message in ascending order of attribute type. The
> receiver of an UPDATE message MUST be prepared to handle path
> attributes within UPDATE messages that are out of order.
Signed-off-by: Hiroki Shirokura <slank.dev@gmail.com>
| -rw-r--r-- | bgpd/bgp_attr.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 2bbcade8e8..316cc957c9 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -2382,15 +2382,6 @@ static bgp_attr_parse_ret_t bgp_attr_psid_sub(uint8_t type, uint16_t length, /* Store label index; subsequently, we'll check on * address-family */ attr->label_index = label_index; - - /* - * Ignore the Label index attribute unless received for - * labeled-unicast - * SAFI. - */ - if (!mp_update->length - || mp_update->safi != SAFI_LABELED_UNICAST) - attr->label_index = BGP_INVALID_LABEL_INDEX; } /* Placeholder code for the IPv6 SID type */ @@ -3078,6 +3069,17 @@ bgp_attr_parse_ret_t bgp_attr_parse(struct peer *peer, struct attr *attr, } } + /* + * draft-ietf-idr-bgp-prefix-sid-27#section-3: + * About Prefix-SID path attribute, + * Label-Index TLV(type1) and The Originator SRGB TLV(type-3) + * may only appear in a BGP Prefix-SID attribute attached to + * IPv4/IPv6 Labeled Unicast prefixes ([RFC8277]). + * It MUST be ignored when received for other BGP AFI/SAFI combinations. + */ + if (!attr->mp_nexthop_len || mp_update->safi != SAFI_LABELED_UNICAST) + attr->label_index = BGP_INVALID_LABEL_INDEX; + /* Check final read pointer is same as end pointer. */ if (BGP_INPUT_PNT(peer) != endp) { flog_warn(EC_BGP_ATTRIBUTES_MISMATCH, |