diff options
authorAhmed Abdelsalam <ahabdels@gmail.com>2020-05-04 14:42:11 +0000
committerDavid S. Miller <davem@davemloft.net>2020-05-06 17:21:35 -0700
commit0cb7498f234e4e7d75187a8cae6c7c2053f2488a (patch)
parentMerge branch 'FDB-fixes-for-Felix-and-Ocelot-switches' (diff)
seg6: fix SRH processing to comply with RFC8754
The Segment Routing Header (SRH) which defines the SRv6 dataplane is defined in RFC8754. RFC8754 (section 4.1) defines the SR source node behavior which encapsulates packets into an outer IPv6 header and SRH. The SR source node encodes the full list of Segments that defines the packet path in the SRH. Then, the first segment from list of Segments is copied into the Destination address of the outer IPv6 header and the packet is sent to the first hop in its path towards the destination. If the Segment list has only one segment, the SR source node can omit the SRH as he only segment is added in the destination address. RFC8754 (section 4.1.1) defines the Reduced SRH, when a source does not require the entire SID list to be preserved in the SRH. A reduced SRH does not contain the first segment of the related SR Policy (the first segment is the one already in the DA of the IPv6 header), and the Last Entry field is set to n-2, where n is the number of elements in the SR Policy. RFC8754 (section defines the SRH processing and the logic to validate the SRH (S09, S10, S11) which works for both reduced and non-reduced behaviors. This patch updates seg6_validate_srh() to validate the SRH as per RFC8754. Signed-off-by: Ahmed Abdelsalam <ahabdels@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 8 insertions, 2 deletions
diff --git a/net/ipv6/seg6.c b/net/ipv6/seg6.c
index 4c7e0a27fa9c..37b434293bda 100644
--- a/net/ipv6/seg6.c
+++ b/net/ipv6/seg6.c
@@ -27,8 +27,9 @@
bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len)
- int trailing;
unsigned int tlv_offset;
+ int max_last_entry;
+ int trailing;
if (srh->type != IPV6_SRCRT_TYPE_4)
return false;
@@ -36,7 +37,12 @@ bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len)
if (((srh->hdrlen + 1) << 3) != len)
return false;
- if (srh->segments_left > srh->first_segment)
+ max_last_entry = (srh->hdrlen / 2) - 1;
+ if (srh->first_segment > max_last_entry)
+ return false;
+ if (srh->segments_left > srh->first_segment + 1)
return false;
tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);