Add optional packet filtered statistics for packet sources

scripts/base/init-bare.zeek

@@ -678,6 +678,7 @@ type NetStats: record {
 	## be always set to zero.
 	pkts_link:    count &default=0;
 	bytes_recvd:  count &default=0;	##< Bytes received by Zeek.
+	filtered:     count &optional;  ##< Packets filtered by the packet source.
 };
 
 type ConnStats: record {

scripts/policy/misc/stats.zeek

@@ -34,6 +34,9 @@ export {
 		## Lag between the wall clock and packet timestamps if reading
 		## live traffic.
 		pkt_lag:       interval  &log &optional;
+		## Number of packets filtered from the link since the last
+		## stats interval if reading live traffic.
+		pkts_filtered: count     &log &optional;
 
 		## Number of events processed since the last stats interval.
 		events_proc:   count     &log;
@@ -140,6 +143,11 @@ event check_stats(then: time, last_ns: NetStats, last_cs: ConnStats, last_ps: Pr
 		info$pkt_lag = current_time() - nettime;
 		info$pkts_dropped = ns$pkts_dropped  - last_ns$pkts_dropped;
 		info$pkts_link = ns$pkts_link  - last_ns$pkts_link;
+
+		# This makes the assumption that if pkts_filtered is valid, it's been valid in
+		# all of the previous calls.
+		if ( ns?$pkts_filtered )
+			info$pkts_filtered = ns$pkts_filtered - last_ns$pkts_filtered;
 		}
 
 	Log::write(Stats::LOG, info);

src/RunState.cc

@@ -414,20 +414,33 @@ void get_final_stats()
 		{
 		iosource::PktSrc::Stats s;
 		ps->Statistics(&s);
-		double dropped_pct = s.dropped > 0.0
-		                         ? ((double)s.dropped / ((double)s.received + (double)s.dropped)) *
-		                               100.0
-		                         : 0.0;
+
+		auto pct = [](uint64_t v, uint64_t received)
+		{
+			return (static_cast<double>(v) /
+			        (static_cast<double>(v) + static_cast<double>(received))) *
+			       100;
+		};
+
+		double dropped_pct = s.dropped > 0 ? pct(s.dropped, s.received) : 0.0;
 
 		uint64_t not_processed = packet_mgr->GetUnprocessedCount();
 		double unprocessed_pct = not_processed > 0
 		                             ? ((double)not_processed / (double)s.received) * 100.0
 		                             : 0.0;
 
+		std::string filtered = "";
+		if ( s.filtered )
+			{
+			double filtered_pct = s.filtered ? pct(s.filtered.value(), s.received) : 0.0;
+			filtered = zeek::util::fmt(" %" PRIu64 " (%.2f%%) filtered", s.filtered.value(),
+			                           filtered_pct);
+			}
+
 		reporter->Info("%" PRIu64 " packets received on interface %s, %" PRIu64
-		               " (%.2f%%) dropped, %" PRIu64 " (%.2f%%) not processed",
+		               " (%.2f%%) dropped, %" PRIu64 " (%.2f%%) not processed%s",
 		               s.received, ps->Path().c_str(), s.dropped, dropped_pct, not_processed,
-		               unprocessed_pct);
+		               unprocessed_pct, filtered.c_str());
 		}
 	}
 

src/iosource/PktSrc.h

@@ -3,6 +3,7 @@
 #pragma once
 
 #include <sys/types.h> // for u_char
+#include <optional>
 #include <vector>
 
 #include "zeek/iosource/BPF_Program.h"
@@ -30,25 +31,28 @@ public:
 		/**
 		 * Packets received by source after filtering (w/o drops).
 		 */
-		uint64_t received;
+		uint64_t received = 0;
 
 		/**
 		 * Packets dropped by source.
 		 */
-		uint64_t dropped; // pkts dropped
+		uint64_t dropped = 0; // pkts dropped
 
 		/**
 		 * Total number of packets on link before filtering.
 		 * Optional, can be left unset if not available.
 		 */
-		uint64_t link;
+		uint64_t link = 0;
 
 		/**
 		 * Bytes received by source after filtering (w/o drops).
 		 */
-		uint64_t bytes_received;
+		uint64_t bytes_received = 0;
 
-		Stats() { received = dropped = link = bytes_received = 0; }
+		/**
+		 * Packets filtered by the packet source.
+		 */
+		std::optional<uint64_t> filtered;
 		};
 
 	/**

src/stats.bif

@@ -39,28 +39,21 @@ zeek::RecordTypePtr ReporterStats;
 ##              get_reporter_stats
 function get_net_stats%(%): NetStats
 	%{
-	uint64_t recv = 0;
-	uint64_t drop = 0;
-	uint64_t link = 0;
-	uint64_t bytes_recv = 0;
+	struct zeek::iosource::PktSrc::Stats stat;
 
 	if ( zeek::iosource::PktSrc* ps = zeek::iosource_mgr->GetPktSrc() )
-		{
-		struct zeek::iosource::PktSrc::Stats stat;
 		ps->Statistics(&stat);
-		recv += stat.received;
-		drop += stat.dropped;
-		link += stat.link;
-		bytes_recv += stat.bytes_received;
-		}
 
 	auto r = zeek::make_intrusive<zeek::RecordVal>(NetStats);
 	int n = 0;
 
-	r->Assign(n++, recv);
-	r->Assign(n++, drop);
-	r->Assign(n++, link);
-	r->Assign(n++, bytes_recv);
+	r->Assign(n++, stat.received);
+	r->Assign(n++, stat.dropped);
+	r->Assign(n++, stat.link);
+	r->Assign(n++, stat.bytes_received);
+
+	if ( stat.filtered )
+		r->Assign(n++, stat.filtered.value());
 
 	return r;
 	%}

testing/btest/Baseline/bifs.net_stats_trace/output

@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[pkts_recvd=136, pkts_dropped=0, pkts_link=0, bytes_recvd=25260]
+[pkts_recvd=136, pkts_dropped=0, pkts_link=0, bytes_recvd=25260, pkts_filtered=<uninitialized>]