Add handling for flowspec in the update path.

Flowspec has no nexthop so adjust up_prep_adjout() to handle a NULL nexthop.
Add the MP_REACH encoding in up_generate_mp_reach for flowspec.
OK tb@

diff --git a/usr.sbin/bgpd/rde_update.c b/usr.sbin/bgpd/rde_update.c
index 9667b4f..f4f993e 100644 (file)
--- a/usr.sbin/bgpd/rde_update.c
+++ b/usr.sbin/bgpd/rde_update.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rde_update.c,v 1.161 2023/03/29 10:46:11 claudio Exp $ */
+/*     $OpenBSD: rde_update.c,v 1.162 2023/04/19 08:30:37 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -460,6 +460,10 @@ up_get_nexthop(struct rde_peer *peer, struct filterstate *state, uint8_t aid)
        case AID_VPN_IPv6:
                peer_local = &peer->local_v6_addr;
                break;
+       case AID_FLOWSPECv4:
+       case AID_FLOWSPECv6:
+               /* flowspec has no nexthop */
+               return (NULL);
        default:
                fatalx("%s, bad AID %s", __func__, aid2str(aid));
        }
@@ -530,7 +534,7 @@ static void
 up_prep_adjout(struct rde_peer *peer, struct filterstate *state, uint8_t aid)
 {
        struct bgpd_addr *nexthop;
-       struct nexthop *nh;
+       struct nexthop *nh = NULL;
        u_char *np;
        uint16_t nl;
 
@@ -545,7 +549,8 @@ up_prep_adjout(struct rde_peer *peer, struct filterstate *state, uint8_t aid)
 
        /* update nexthop */
        nexthop = up_get_nexthop(peer, state, aid);
-       nh = nexthop_get(nexthop);
+       if (nexthop != NULL)
+               nh = nexthop_get(nexthop);
        nexthop_unref(state->nexthop);
        state->nexthop = nh;
        state->nhflags = 0;
@@ -1048,6 +1053,19 @@ up_generate_mp_reach(u_char *buf, int len, struct rde_peer *peer,
                nexthop = &state->nexthop->exit_nexthop;
                memcpy(attrbuf, &nexthop->v6, sizeof(struct in6_addr));
                break;
+       case AID_FLOWSPECv4:
+       case AID_FLOWSPECv6:
+               attrlen = 5; /* AFI + SAFI + NH LEN + NH + Reserved */
+               if (len < wpos + attrlen)
+                       return (-1);
+               wpos += attrlen;
+               if (aid2afi(aid, &tmp, &attrbuf[2]))
+                       fatalx("up_generate_mp_reachi: bad AID");
+               tmp = htons(tmp);
+               memcpy(attrbuf, &tmp, sizeof(tmp));
+               attrbuf[3] = 0; /* nh len MUST be 0 */
+               attrbuf[4] = 0; /* Reserved must be 0 */
+               break;
        default:
                fatalx("up_generate_mp_reach: unknown AID");
        }