diff --git a/doc/bird.sgml b/doc/bird.sgml
index 10c6f121e918265a81c72062f459e0f9f56299d3..8834c1cb359e5f4ebf7d48dafc249b77320cc4b8 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -3157,6 +3157,23 @@ using the following configuration parameters:
negotiation. If the proposed hold time would lead to a lower value of
the keepalive time, the session is rejected with error. Default: none.
+ <tag><label id="bgp-send-hold-time">send hold time <m/number/</tag>
+ Maximum time in seconds betweeen successfull transmissions of BGP messages.
+ Send hold timer drops the session if the neighbor is sending keepalives,
+ but does not receive our messages, causing the TCP connection to stall.
+ This may happen due to malfunctioning or overwhelmed neighbor. See
+ <HTMLURL URL="https://datatracker.ietf.org/doc/draft-ietf-idr-bgp-sendholdtimer/"
+ name="draft-ietf-idr-bgp-sendholdtimer"> for more details.
+
+ Like the option <cf/keepalive time/, the effective value depends on the
+ negotiated hold time, as it is scaled to maintain proportion between the
+ send hold time and the keepalive time. If it is set to zero, the timer
+ is disabled. Default: double of the hold timer limit.
+
+ The option <cf/disable rx/ is intended only for testing this feature and
+ should not be used anywhere else. It discards received messages and
+ disables the hold timer.
+
<tag><label id="bgp-connect-delay-time">connect delay time <m/number/</tag>
Delay in seconds between protocol startup and the first attempt to
connect. Default: 5 seconds.
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index b14df932fb40b0f043046233bdcb1b91a79babaf..9d4671afc4fe7950743a67dfa09a58d6137537a8 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -375,6 +375,8 @@ bgp_close_conn(struct bgp_conn *conn)
conn->keepalive_timer = NULL;
rfree(conn->hold_timer);
conn->hold_timer = NULL;
+ rfree(conn->send_hold_timer);
+ conn->send_hold_timer = NULL;
rfree(conn->tx_ev);
conn->tx_ev = NULL;
rfree(conn->sk);
@@ -673,6 +675,13 @@ bgp_conn_enter_established_state(struct bgp_conn *conn)
p->channel_map[c->index] = c;
}
+ /* Breaking rx_hook for simulating receive problem */
+ if (p->cf->disable_rx)
+ {
+ conn->sk->rx_hook = NULL;
+ tm_stop(conn->hold_timer);
+ }
+
/* proto_notify_state() will likely call bgp_feed_begin(), setting c->feed_state */
bgp_conn_set_state(conn, BS_ESTABLISHED);
@@ -1044,6 +1053,27 @@ bgp_keepalive_timeout(timer *t)
ev_run(conn->tx_ev);
}
+void
+bgp_send_hold_timeout(timer *t)
+{
+ struct bgp_conn *conn = t->data;
+ struct bgp_proto *p = conn->bgp;
+
+ if (conn->state == BS_CLOSE)
+ return;
+
+ /* Error codes not yet assigned by IANA */
+ uint code = 4;
+ uint subcode = 1;
+
+ /* Like bgp_error() but without NOTIFICATION */
+ bgp_log_error(p, BE_BGP_TX, "Error", code, subcode, NULL, 0);
+ bgp_store_error(p, conn, BE_BGP_TX, (code << 16) | subcode);
+ bgp_conn_enter_idle_state(conn);
+ bgp_update_startup_delay(p);
+ bgp_stop(p, 0, NULL, 0);
+}
+
static void
bgp_setup_conn(struct bgp_proto *p, struct bgp_conn *conn)
{
@@ -1058,6 +1088,7 @@ bgp_setup_conn(struct bgp_proto *p, struct bgp_conn *conn)
conn->connect_timer = tm_new_init(p->p.pool, bgp_connect_timeout, conn, 0, 0);
conn->hold_timer = tm_new_init(p->p.pool, bgp_hold_timeout, conn, 0, 0);
conn->keepalive_timer = tm_new_init(p->p.pool, bgp_keepalive_timeout, conn, 0, 0);
+ conn->send_hold_timer = tm_new_init(p->p.pool, bgp_send_hold_timeout, conn, 0, 0);
conn->tx_ev = ev_new_init(p->p.pool, bgp_kick_tx, conn);
}
@@ -2619,7 +2650,9 @@ bgp_show_proto_info(struct proto *P)
tm_remains(p->conn->hold_timer), p->conn->hold_time);
cli_msg(-1006, " Keepalive timer: %t/%u",
tm_remains(p->conn->keepalive_timer), p->conn->keepalive_time);
- }
+ cli_msg(-1006, " Send hold timer: %t/%u",
+ tm_remains(p->conn->send_hold_timer), p->conn->send_hold_time);
+}
#if 0
struct bgp_stats *s = &p->stats;
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 61127562b5e7c79f6a9fcb29f03792992b831dde..7127bc88a38aad31d9bee4e68d57733a4bb8d3d5 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -117,6 +117,8 @@ struct bgp_config {
int setkey; /* Set MD5 password to system SA/SP database */
u8 local_role; /* Set peering role with neighbor [RFC 9234] */
int require_roles; /* Require configured roles on both sides */
+ int send_hold_time;
+ int disable_rx; /* Stop reading messages after handshake (for simulating error) */
/* Times below are in seconds */
unsigned gr_time; /* Graceful restart timeout */
unsigned llgr_time; /* Long-lived graceful restart stale time */
@@ -307,6 +309,7 @@ struct bgp_conn {
timer *connect_timer;
timer *hold_timer;
timer *keepalive_timer;
+ timer *send_hold_timer;
event *tx_ev;
u32 packets_to_send; /* Bitmap of packet types to be sent */
u32 channels_to_send; /* Bitmap of channels with packets to be sent */
@@ -315,7 +318,7 @@ struct bgp_conn {
int notify_code, notify_subcode, notify_size;
byte *notify_data;
- uint hold_time, keepalive_time; /* Times calculated from my and neighbor's requirements */
+ uint hold_time, keepalive_time, send_hold_time; /* Times calculated from my and neighbor's requirements */
};
struct bgp_proto {
@@ -558,6 +561,7 @@ void bgp_conn_enter_openconfirm_state(struct bgp_conn *conn);
void bgp_conn_enter_established_state(struct bgp_conn *conn);
void bgp_conn_enter_close_state(struct bgp_conn *conn);
void bgp_conn_enter_idle_state(struct bgp_conn *conn);
+void broke_bgp_listening(struct channel *C);
void bgp_handle_graceful_restart(struct bgp_proto *p);
void bgp_graceful_restart_done(struct bgp_channel *c);
void bgp_refresh_begin(struct bgp_channel *c);
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 0fcbb27664133a74e5066f747d52175840bee869..1173ff060079c2c2ebd338d11634c5a36b5b4719 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -32,7 +32,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL, SETS,
DYNAMIC, RANGE, NAME, DIGITS, BGP_AIGP, AIGP, ORIGINATE, COST, ENFORCE,
FIRST, FREE, VALIDATE, BASE, ROLE, ROLES, PEER, PROVIDER, CUSTOMER,
- RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC, GLOBAL)
+ RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC, GLOBAL, SEND)
%type <i> bgp_nh
%type <i32> bgp_afi
@@ -77,6 +77,7 @@ bgp_proto_start: proto_start BGP {
BGP_CFG->local_role = BGP_ROLE_UNDEFINED;
BGP_CFG->dynamic_name = "dynbgp";
BGP_CFG->check_link = -1;
+ BGP_CFG->send_hold_time = -1;
}
;
@@ -182,6 +183,7 @@ bgp_proto:
| bgp_proto CONNECT RETRY TIME expr ';' { BGP_CFG->connect_retry_time = $5; }
| bgp_proto KEEPALIVE TIME expr ';' { BGP_CFG->keepalive_time = $4; if (($4<1) || ($4>65535)) cf_error("Keepalive time must be in range 1-65535"); }
| bgp_proto MIN KEEPALIVE TIME expr ';' { BGP_CFG->min_keepalive_time = $5; }
+ | bgp_proto SEND HOLD TIME expr';' { BGP_CFG->send_hold_time = $5; }
| bgp_proto ERROR FORGET TIME expr ';' { BGP_CFG->error_amnesia_time = $5; }
| bgp_proto ERROR WAIT TIME expr ',' expr ';' { BGP_CFG->error_delay_time_min = $5; BGP_CFG->error_delay_time_max = $7; }
| bgp_proto DISABLE AFTER ERROR bool ';' { BGP_CFG->disable_after_error = $5; }
@@ -222,6 +224,7 @@ bgp_proto:
| bgp_proto ENFORCE FIRST AS bool ';' { BGP_CFG->enforce_first_as = $5; }
| bgp_proto LOCAL ROLE bgp_role_name ';' { BGP_CFG->local_role = $4; }
| bgp_proto REQUIRE ROLES bool ';' { BGP_CFG->require_roles = $4; }
+ | bgp_proto DISABLE RX bool ';' { BGP_CFG->disable_rx = $4; }
;
bgp_afi:
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index 1e5a226f42526a4a8145a177800d2e7530f5b95f..e8cc4718730f31211ecad1c272109a7b0c008264 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -926,6 +926,10 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
(p->cf->keepalive_time * hold_time / p->cf->hold_time) :
hold_time / 3;
+ uint send_hold_time = (p->cf->send_hold_time >= 0) ?
+ (p->cf->send_hold_time * hold_time / p->cf->hold_time) :
+ 2 * hold_time;
+
/* Keepalive time might be rounded down to zero */
if (hold_time && !keepalive_time)
keepalive_time = 1;
@@ -1034,6 +1038,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
/* Update our local variables */
conn->hold_time = hold_time;
conn->keepalive_time = keepalive_time;
+ conn->send_hold_time = send_hold_time;
conn->as4_session = conn->local_caps->as4_support && caps->as4_support;
conn->ext_messages = conn->local_caps->ext_messages && caps->ext_messages;
p->remote_id = id;
@@ -1043,6 +1048,7 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
bgp_schedule_packet(conn, NULL, PKT_KEEPALIVE);
bgp_start_timer(conn->hold_timer, conn->hold_time);
+ bgp_start_timer(conn->send_hold_timer, conn->send_hold_time);
bgp_conn_enter_openconfirm_state(conn);
}
@@ -3060,7 +3066,11 @@ bgp_send(struct bgp_conn *conn, uint type, uint len)
put_u16(buf+16, len);
buf[18] = type;
- return sk_send(sk, len);
+ int success = sk_send(sk, len);
+ if (success && ((conn->state == BS_ESTABLISHED) || (conn->state == BS_OPENCONFIRM)))
+ bgp_start_timer(conn->send_hold_timer, conn->send_hold_time);
+
+ return success;
}
/**
@@ -3220,6 +3230,10 @@ bgp_tx(sock *sk)
{
struct bgp_conn *conn = sk->data;
+ /* Pending message was passed to kernel */
+ if ((conn->state == BS_ESTABLISHED) || (conn->state == BS_OPENCONFIRM))
+ bgp_start_timer(conn->send_hold_timer, conn->send_hold_time);
+
DBG("BGP: TX hook\n");
uint max = 1024;
while (--max && (bgp_fire_tx(conn) > 0))
@@ -3261,6 +3275,7 @@ static struct {
{ 3, 10, "Invalid network field" },
{ 3, 11, "Malformed AS_PATH" },
{ 4, 0, "Hold timer expired" },
+ { 4, 1, "Send hold timer expired" }, /* Provisional [draft-ietf-idr-bgp-sendholdtimer] */
{ 5, 0, "Finite state machine error" }, /* Subcodes are according to [RFC6608] */
{ 5, 1, "Unexpected message in OpenSent state" },
{ 5, 2, "Unexpected message in OpenConfirm state" },