From 1f6ecd7e19495422256590122ac48f8e5fbbf676 Mon Sep 17 00:00:00 2001
From: Katerina Kubecova <katerina.kubecova@nic.cz>
Date: Mon, 16 Dec 2024 11:37:10 +0100
Subject: [PATCH] BGP: Print warnings when the allocated memory is larger than
 given acceptable maximum.

---
 doc/bird.sgml      | 5 +++++
 proto/bgp/attrs.c  | 7 +++++++
 proto/bgp/bgp.c    | 2 ++
 proto/bgp/bgp.h    | 2 ++
 proto/bgp/config.Y | 4 +++-
 5 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/doc/bird.sgml b/doc/bird.sgml
index f7519b81..09f711a9 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -3419,6 +3419,11 @@ using the following configuration parameters:
 	otherwise the session will not be established. This behavior is defined
 	in <rfc id="9234"> as "strict mode" and is used to enforce corresponding
 	configuration at your conterpart side. Default: disabled.
+
+        <tag><label id="bgp-tx_size_warning">tx size warning <m/number/</tag>
+        If this option is set, the bgp protocol prints warning when it consumes at least
+        given size of memory. This includes also the memory consumed
+	by any export table. Zero means disabled. Default: disabled.
 </descrip>
 
 <sect1>Channel configuration
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index 957fe108..a2feaef5 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -2413,6 +2413,13 @@ bgp_rt_notify(struct proto *P, struct channel *C, const net_addr *n, rte *new, c
   /* And queue the notification */
   if (bgp_update_prefix(c, bgp_get_prefix(c, NET_TO_INDEX(n), path, bc->add_path_tx), buck))
     bgp_schedule_packet(p->conn, bc, PKT_UPDATE);
+
+  if ((p->cf->tx_size_warning > 0) )
+  {
+    struct resmem mem = rmemsize(P->pool);
+    if (mem.effective + mem.overhead >= p->cf->tx_size_warning)
+      log_rl(&p->tbf_mem, L_WARN "%s: Used %lu memory", P->name, mem.effective + mem.overhead);
+  }
 }
 
 
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index ea9392ff..5fc2b5ff 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -2019,6 +2019,8 @@ bgp_init(struct proto_config *CF)
   ea_set_attr(&pes, EA_LITERAL_EMBEDDED(&ea_bgp_rem_as, 0, cf->remote_as));
 
   proto_announce_state_later(&p->p, pes);
+
+  p->tbf_mem = (struct tbf) TBF_DEFAULT_LOG_LIMITS;
   return P;
 }
 
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index c12942ec..202e78ba 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -146,6 +146,7 @@ struct bgp_config {
   int require_hostname;			/* Require remote support for hostname [draft] */
   int require_gr;			/* Require remote support for graceful restart [RFC 4724] */
   int require_llgr;			/* Require remote support for long-lived graceful restart [draft] */
+  uint tx_size_warning;			/* The maximum amount of memory which is not logged as warning */
   struct bfd_options *bfd;		/* Use BFD for liveness detection */
 };
 
@@ -392,6 +393,7 @@ struct bgp_proto {
   u8 last_error_class; 			/* Error class of last error */
   u32 last_error_code;			/* Error code of last error. BGP protocol errors
 					   are encoded as (bgp_err_code << 16 | bgp_err_subcode) */
+  struct tbf tbf_mem;                   /* For logging memory allocation */
 };
 
 #define bgp_ea_state(p)  _Generic((p), \
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 90dfc905..aafd44ff 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -31,7 +31,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL, SETS,
 	DYNAMIC, RANGE, NAME, DIGITS, AIGP, ORIGINATE, COST, ENFORCE,
 	FIRST, FREE, VALIDATE, BASE, ROLE, ROLES, PEER, PROVIDER, CUSTOMER,
-	RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC, GLOBAL, SEND)
+	RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC, GLOBAL, SEND, TX, SIZE, WARNING)
 
 CF_ENUM(T_ENUM_BGP_ORIGIN, ORIGIN_, IGP, EGP, INCOMPLETE)
 
@@ -80,6 +80,7 @@ bgp_proto_start: proto_start BGP {
      BGP_CFG->dynamic_name = "dynbgp";
      BGP_CFG->check_link = -1;
      BGP_CFG->send_hold_time = -1;
+     BGP_CFG->tx_size_warning = 0;
    }
  ;
 
@@ -227,6 +228,7 @@ bgp_proto:
  | 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_proto TX SIZE WARNING expr ';' { BGP_CFG->tx_size_warning = $5; }
  ;
 
 bgp_afi: