net: stats: dns: Collect DNS statistics

If DNS statistics is enabled in Kconfig, then start to collect it. This is useful in order to see how many DNS requests/responses received or sent, and also see the amount of dropped DNS packets. Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>
ZEISS · Sep 25, 2024 · 765bfbb · 765bfbb
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diff --git a/include/zephyr/net/net_stats.h b/include/zephyr/net/net_stats.h
@@ -226,6 +226,20 @@ struct net_stats_ipv4_igmp {
 	net_stats_t drop;
 };
 
+/**
+ * @brief DNS statistics
+ */
+struct net_stats_dns {
+	/** Number of received DNS queries */
+	net_stats_t recv;
+
+	/** Number of sent DNS responses */
+	net_stats_t sent;
+
+	/** Number of dropped DNS packets */
+	net_stats_t drop;
+};
+
 /**
  * @brief Network packet transfer times for calculating average TX time
  */
@@ -375,6 +389,11 @@ struct net_stats {
 	struct net_stats_ipv4_igmp ipv4_igmp;
 #endif
 
+#if defined(CONFIG_NET_STATISTICS_DNS)
+	/** DNS statistics */
+	struct net_stats_dns dns;
+#endif
+
 #if NET_TC_COUNT > 1
 	/** Traffic class statistics */
 	struct net_stats_tc tc;

diff --git a/subsys/net/ip/Kconfig.stats b/subsys/net/ip/Kconfig.stats
@@ -93,6 +93,13 @@ config NET_STATISTICS_IGMP
 	help
 	  Keep track of IGMP related statistics
 
+config NET_STATISTICS_DNS
+	bool "Domain Name Service (DNS) statistics"
+	depends on DNS_RESOLVER || MDNS_RESPONDER || LLMNR_RESPONDER
+	default y
+	help
+	  Keep track of DNS related statistics
+
 config NET_STATISTICS_PPP
 	bool "Point-to-point (PPP) statistics"
 	depends on NET_L2_PPP

diff --git a/subsys/net/ip/net_stats.h b/subsys/net/ip/net_stats.h
@@ -345,6 +345,27 @@ static inline void net_stats_update_ipv4_igmp_drop(struct net_if *iface)
 #define net_stats_update_ipv4_igmp_drop(iface)
 #endif /* CONFIG_NET_STATISTICS_IGMP */
 
+#if defined(CONFIG_NET_STATISTICS_DNS)
+static inline void net_stats_update_dns_recv(struct net_if *iface)
+{
+	UPDATE_STAT(iface, stats.dns.recv++);
+}
+
+static inline void net_stats_update_dns_sent(struct net_if *iface)
+{
+	UPDATE_STAT(iface, stats.dns.sent++);
+}
+
+static inline void net_stats_update_dns_drop(struct net_if *iface)
+{
+	UPDATE_STAT(iface, stats.dns.drop++);
+}
+#else
+#define net_stats_update_dns_recv(iface)
+#define net_stats_update_dns_sent(iface)
+#define net_stats_update_dns_drop(iface)
+#endif /* CONFIG_NET_STATISTICS_DNS */
+
 #if defined(CONFIG_NET_PKT_TXTIME_STATS) && defined(CONFIG_NET_STATISTICS)
 static inline void net_stats_update_tx_time(struct net_if *iface,
 					    uint32_t start_time,

diff --git a/subsys/net/lib/dns/dispatcher.c b/subsys/net/lib/dns/dispatcher.c
@@ -11,9 +11,11 @@ LOG_MODULE_REGISTER(net_dns_dispatcher, CONFIG_DNS_SOCKET_DISPATCHER_LOG_LEVEL);
 #include <zephyr/sys/check.h>
 #include <zephyr/sys/slist.h>
 #include <zephyr/net_buf.h>
+#include <zephyr/net/net_if.h>
 #include <zephyr/net/dns_resolve.h>
 #include <zephyr/net/socket_service.h>
 
+#include "../../ip/net_stats.h"
 #include "dns_pack.h"
 
 static K_MUTEX_DEFINE(lock);
@@ -95,6 +97,24 @@ static int dns_dispatch(struct dns_socket_dispatcher *dispatcher,
 	}
 
 done:
+	if (IS_ENABLED(CONFIG_NET_STATISTICS_DNS)) {
+		struct net_if *iface = NULL;
+
+		if (IS_ENABLED(CONFIG_NET_IPV6) && addr->sa_family == AF_INET6) {
+			iface = net_if_ipv6_select_src_iface(&net_sin6(addr)->sin6_addr);
+		} else if (IS_ENABLED(CONFIG_NET_IPV4) && addr->sa_family == AF_INET) {
+			iface = net_if_ipv4_select_src_iface(&net_sin(addr)->sin_addr);
+		}
+
+		if (iface != NULL) {
+			if (ret < 0) {
+				net_stats_update_dns_drop(iface);
+			} else {
+				net_stats_update_dns_recv(iface);
+			}
+		}
+	}
+
 	return ret;
 }
 

diff --git a/subsys/net/lib/dns/llmnr_responder.c b/subsys/net/lib/dns/llmnr_responder.c
@@ -30,6 +30,7 @@ LOG_MODULE_REGISTER(net_llmnr_responder, CONFIG_LLMNR_RESPONDER_LOG_LEVEL);
 
 #include "dns_pack.h"
 #include "ipv6.h"
+#include "../../ip/net_stats.h"
 
 #include "net_private.h"
 
@@ -401,6 +402,19 @@ static int send_response(int sock,
 			net_sprint_ipv4_addr(&net_sin((struct sockaddr *)&dst)->sin_addr) :
 			net_sprint_ipv6_addr(&net_sin6((struct sockaddr *)&dst)->sin6_addr),
 			ret);
+	} else {
+		struct net_if *iface = NULL;
+		struct sockaddr *addr = (struct sockaddr *)&dst;
+
+		if (IS_ENABLED(CONFIG_NET_IPV6) && src_addr->sa_family == AF_INET6) {
+			iface = net_if_ipv6_select_src_iface(&net_sin6(addr)->sin6_addr);
+		} else if (IS_ENABLED(CONFIG_NET_IPV4) && src_addr->sa_family == AF_INET) {
+			iface = net_if_ipv4_select_src_iface(&net_sin(addr)->sin_addr);
+		}
+
+		if (iface != NULL) {
+			net_stats_update_dns_sent(iface);
+		}
 	}
 
 	return ret;

diff --git a/subsys/net/lib/dns/mdns_responder.c b/subsys/net/lib/dns/mdns_responder.c
@@ -32,6 +32,7 @@ LOG_MODULE_REGISTER(net_mdns_responder, CONFIG_MDNS_RESPONDER_LOG_LEVEL);
 #include "dns_sd.h"
 #include "dns_pack.h"
 #include "ipv6.h"
+#include "../../ip/net_stats.h"
 
 #include "net_private.h"
 
@@ -336,6 +337,8 @@ static int send_response(int sock,
 			   (struct sockaddr *)&dst, dst_len);
 	if (ret < 0) {
 		NET_DBG("Cannot send %s reply (%d)", "mDNS", ret);
+	} else {
+		net_stats_update_dns_sent(iface);
 	}
 
 	return ret;
@@ -496,6 +499,8 @@ static void send_sd_response(int sock,
 			if (ret < 0) {
 				NET_DBG("Cannot send %s reply (%d)", "mDNS", ret);
 				continue;
+			} else {
+				net_stats_update_dns_sent(iface);
 			}
 		}
 	}

diff --git a/subsys/net/lib/dns/resolve.c b/subsys/net/lib/dns/resolve.c
@@ -29,6 +29,7 @@ LOG_MODULE_REGISTER(net_dns_resolve, CONFIG_DNS_RESOLVER_LOG_LEVEL);
 #include "dns_pack.h"
 #include "dns_internal.h"
 #include "dns_cache.h"
+#include "../../ip/net_stats.h"
 
 #define DNS_SERVER_COUNT CONFIG_DNS_RESOLVER_MAX_SERVERS
 #define SERVER_COUNT     (DNS_SERVER_COUNT + DNS_MAX_MCAST_SERVERS)
@@ -1041,6 +1042,20 @@ static int dns_write(struct dns_resolve_context *ctx,
 	if (ret < 0) {
 		NET_DBG("Cannot send query (%d)", -errno);
 		return ret;
+	} else {
+		if (IS_ENABLED(CONFIG_NET_STATISTICS_DNS)) {
+			struct net_if *iface = NULL;
+
+			if (IS_ENABLED(CONFIG_NET_IPV6) && server->sa_family == AF_INET6) {
+				iface = net_if_ipv6_select_src_iface(&net_sin6(server)->sin6_addr);
+			} else if (IS_ENABLED(CONFIG_NET_IPV4) && server->sa_family == AF_INET) {
+				iface = net_if_ipv4_select_src_iface(&net_sin(server)->sin_addr);
+			}
+
+			if (iface != NULL) {
+				net_stats_update_dns_sent(iface);
+			}
+		}
 	}
 
 	return 0;

diff --git a/subsys/net/lib/shell/stats.c b/subsys/net/lib/shell/stats.c
@@ -537,6 +537,12 @@ static void net_shell_print_statistics(struct net_if *iface, void *user_data)
 	   GET_STAT(iface, tcp.connrst));
 	PR("TCP pkt drop   %d\n", GET_STAT(iface, tcp.drop));
 #endif
+#if defined(CONFIG_NET_STATISTICS_DNS)
+	PR("DNS recv       %d\tsent\t%d\tdrop\t%d\n",
+	   GET_STAT(iface, dns.recv),
+	   GET_STAT(iface, dns.sent),
+	   GET_STAT(iface, dns.drop));
+#endif /* CONFIG_NET_STATISTICS_DNS */
 
 	PR("Bytes received %u\n", GET_STAT(iface, bytes.received));
 	PR("Bytes sent     %u\n", GET_STAT(iface, bytes.sent));