bgpd: add new draft for redirect ip for flowspec

that new option will overwrite simpson draft. There is a new ecommunity
option whose type is 0x1 and subtype is 0xc. That option is defined
here on iana.org/assignments/bgp-extended-communities page:
- bgp-extended-communities.xhtml#trans-ipv4
It contains the IP address to redirect traffic to. The understanding of
the draft is the following one:
- if that community is only present, then the ip contained inside will
be chosen as nexthop.
- if that community is provided along with simpson extended community,
then only the new redirect ip draft will be used. however, both will be
displayed.
- in other cases, if there is only the simpson extended community, then
the nexthop IP of the NLRI will be chosen.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/bgpd/bgp_ecommunity.c b/bgpd/bgp_ecommunity.c
index 802916418..ed0900a72 100644
--- a/bgpd/bgp_ecommunity.c
+++ b/bgpd/bgp_ecommunity.c
@@ -688,9 +688,23 @@ char *ecommunity_ecom2str(struct ecommunity *ecom, int format, int filter)
 			/* Low-order octet of type. */
 			sub_type = *pnt++;
 			if (sub_type != ECOMMUNITY_ROUTE_TARGET
-			    && sub_type != ECOMMUNITY_SITE_ORIGIN)
-				unk_ecom = 1;
-			else
+			    && sub_type != ECOMMUNITY_SITE_ORIGIN) {
+				if (sub_type ==
+				    ECOMMUNITY_FLOWSPEC_REDIRECT_IPV4 &&
+				    type == ECOMMUNITY_ENCODE_IP) {
+					struct in_addr *ipv4 =
+						(struct in_addr *)pnt;
+					char ipv4str[INET_ADDRSTRLEN];
+
+					inet_ntop(AF_INET, ipv4,
+						  ipv4str,
+						  INET_ADDRSTRLEN);
+					len = sprintf(str_buf + str_pnt,
+						      "NH:%s:%d",
+						      ipv4str, pnt[5]);
+				} else
+					unk_ecom = 1;
+			} else
 				len = ecommunity_rt_soo_str(str_buf + str_pnt,
 							    pnt, type, sub_type,
 							    format);