isisd: Advertise SRv6 Locator in Prefix Reach TLV

According to RFC 9352 section #5, the SRv6 Locators associated with
algorithms 0 and 1 should be also advertised in a Prefix Reachability
TLV (236 or 237) to allow legacy routers (i.e., routers that do not
support SRv6) installing a forwarding entry for algorithms 0 and 1 SRv6
traffic.

This commits extend IS-IS to advertise SRv6 Locators in IPv6
Reachability TLV.

Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>

diff --git a/isisd/isis_lsp.c b/isisd/isis_lsp.c
index e5970f6509596aec9bde84682857f7e31f55ef25..1b3491f5d38e3c48dc8c31629f62a9042e918501 100644 (file)
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -1262,6 +1262,10 @@ static void lsp_build(struct isis_lsp *lsp, struct isis_area *area)
                          area->area_tag);
 
                list_delete(&locator.srv6_sid);
+
+               isis_tlvs_add_ipv6_reach(lsp->tlvs,
+                                        isis_area_ipv6_topology(area),
+                                        &chunk->prefix, 0, false, NULL);
        }
 
        /* IPv4 address and TE router ID TLVs.