A cache can send a 'NO_DATA_AVAILABLE' error during version negotiation

so handle this case as well. This error triggers an RTR_EVNT_NO_DATA
event that moves the session to RTR_STATE_ESTABLISHED (and out of negotiation).

When there is no data available the session_id remains unset until data
becomes available. So handle this case not only in rtr_parse_cache_response()
but also in rtr_parse_notify().

RTR_EVNT_NO_DATA arms the RTR_EVNT_TIMER_RETRY timer. On expiry send a
reset or serial query depending on the cache session state.

OK tb@

diff --git a/usr.sbin/bgpd/rtr_proto.c b/usr.sbin/bgpd/rtr_proto.c
index 46a0434..958d438 100644 (file)
--- a/usr.sbin/bgpd/rtr_proto.c
+++ b/usr.sbin/bgpd/rtr_proto.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rtr_proto.c,v 1.31 2024/01/11 15:38:05 claudio Exp $ */
+/*     $OpenBSD: rtr_proto.c,v 1.32 2024/01/15 11:55:26 claudio Exp $ */
 
 /*
  * Copyright (c) 2020 Claudio Jeker <claudio@openbsd.org>
@@ -419,6 +419,7 @@ rtr_parse_header(struct rtr_session *rs, struct ibuf *hdr,
 {
        struct rtr_header rh;
        size_t len;
+       uint16_t errcode;
 
        if (ibuf_get(hdr, &rh, sizeof(rh)) == -1)
                fatal("%s: ibuf_get", __func__);
@@ -443,7 +444,14 @@ rtr_parse_header(struct rtr_session *rs, struct ibuf *hdr,
                        rtr_fsm(rs, RTR_EVNT_NEGOTIATION_DONE);
                        break;
                case ERROR_REPORT:
-                       /* version handled in rtr_parse_error() */
+                       errcode = ntohs(rh.session_id);
+                       if (errcode == UNSUPP_PROTOCOL_VERS ||
+                           errcode == NO_DATA_AVAILABLE) {
+                               if (rh.version < rs->version) {
+                                       rs->prev_version = rs->version;
+                                       rs->version = rh.version;
+                               }
+                       }
                        break;
                case SERIAL_NOTIFY:
                        /* ignore SERIAL_NOTIFY */
@@ -537,6 +545,10 @@ rtr_parse_notify(struct rtr_session *rs, struct ibuf *pdu)
        if (ibuf_get(pdu, &notify, sizeof(notify)) == -1)
                goto badlen;
 
+       /* set session_id if not yet happened */
+       if (rs->session_id == -1)
+               rs->session_id = ntohs(notify.hdr.session_id);
+
        if (rtr_check_session_id(rs, rs->session_id, &notify.hdr, pdu) == -1)
                return -1;
 
@@ -960,10 +972,6 @@ rtr_parse_error(struct rtr_session *rs, struct ibuf *pdu)
                rtr_fsm(rs, RTR_EVNT_NO_DATA);
                rv = 0;
        } else if (errcode == UNSUPP_PROTOCOL_VERS) {
-               if (rh.version < rs->version) {
-                       rs->prev_version = rs->version;
-                       rs->version = rh.version;
-               }
                rtr_fsm(rs, RTR_EVNT_UNSUPP_PROTO_VERSION);
                rv = 0;
        } else
@@ -1126,6 +1134,11 @@ rtr_fsm(struct rtr_session *rs, enum rtr_event event)
                        timer_set(&rs->timers, Timer_Rtr_Retry, rs->retry);
                        rtr_imsg_compose(IMSG_SOCKET_CONN, rs->id, 0, NULL, 0);
                        break;
+               case RTR_STATE_ESTABLISHED:
+                       if (rs->session_id == -1)
+                               rtr_send_reset_query(rs);
+                       else
+                               rtr_send_serial_query(rs);
                default:
                        break;
                }