libethernet: add support to read stats for bridge

* Read stats and extended stats for bridge in ethernet.

Note: Supported only for broadcom for now

bcm/bcm.c

@@ -276,12 +276,13 @@ static int bcm_eth_get_stats_from_proc(const char *ifname, struct eth_stats *s)
 	return 0;
 }
 
-int bcm_eth_get_stats(const char *ifname, struct eth_stats *s)
+
+static int read_eth_stats(const char *ifname, struct eth_stats *s)
 {
+	int ret_proc;
 	struct ethswctl_data data;
 	int unit = -1;
 	int port = -1;
-	int ret_proc;
 	int ret;
 
 	/* get from proc first */
@@ -331,6 +332,79 @@ int bcm_eth_get_stats(const char *ifname, struct eth_stats *s)
 	return 0;
 }
 
+
+static void reinit_extended_stats_for_bridge(struct eth_stats *to)
+{
+	// In case of bridge, function to read all stats has already
+	// been called once, which might have stored garbage in the
+	// extended stats, so important to reinit here.
+	to->tx_ucast_packets = 0;
+	to->rx_ucast_packets = 0;
+	to->tx_mcast_packets = 0;
+	to->rx_mcast_packets = 0;
+	to->tx_bcast_packets = 0;
+	to->rx_bcast_packets = 0;
+	to->rx_unknown_packets = 0;
+}
+
+
+// This function adds up the extended stats to get cumulative stats
+// for the bridge type interfaces.
+static void add_to_stats(struct eth_stats *to, struct eth_stats *from)
+{
+	to->tx_ucast_packets += from->tx_ucast_packets;
+	to->rx_ucast_packets += from->rx_ucast_packets;
+	to->tx_mcast_packets += from->tx_mcast_packets;
+	to->rx_mcast_packets += from->rx_mcast_packets;
+	to->tx_bcast_packets += from->tx_bcast_packets;
+	to->rx_bcast_packets += from->rx_bcast_packets;
+	to->rx_unknown_packets += from->rx_unknown_packets;
+}
+
+
+int bcm_eth_get_stats(const char *ifname, struct eth_stats *s)
+{
+
+	if (read_eth_stats(ifname, s)) {
+		libethernet_err("error in reading stats for interface %s\n", ifname);
+		return -1;
+	}
+
+	if (if_isbridge(ifname)) {
+		// read stats for each interface in bridge and add them to get
+		// bridge stats
+		struct eth_stats temp;
+		int ret = 0;
+		char ifnames[32][16] = {0};
+		int count, i;
+
+		ret = br_get_iflist(ifname, &count, ifnames);
+		if ((count <= 0) || (ret < 0)) // empty bridge
+			return 0;
+
+		// only extended stats are not available for bridge interfaces,
+		// we have already read the available stats above and now loop
+		// on the member ports to get the extended stats for each port
+		// and add those up to get the extended stats for the bridge
+		reinit_extended_stats_for_bridge(s);
+		for (i = 0; i < count; i++) {
+			memset(&temp, 0, sizeof(struct eth_stats));
+
+			if (strncmp("eth", ifnames[i], 3) != 0)
+				continue;
+
+			if (read_eth_stats(ifnames[i], &temp)) {
+				libethernet_err("error in reading stats for interface %s\n", ifnames[i]);
+				continue; // no need to add this to bridge stats
+			}
+
+			add_to_stats(s, &temp);
+		}
+	}
+
+	return 0;
+}
+
 int bcm_eth_get_rmon_stats(const char *ifname, struct eth_rmon_stats *rmon)
 {
 	struct ethswctl_data data;

ethernet.c

@@ -66,6 +66,14 @@ const struct eth_ops *get_eth_driver(const char *ifname)
 			return eth_ops[i];
 	}
 
+	// The plan is to have this support in broadcom only for now, that is,
+	// we will present bridge level stats for broadcom only for now, hence,
+	// this, in the long term, we should add this support for all platforms.
+#ifdef IOPSYS_BROADCOM
+	if (if_isbridge(ifname)) {
+		return eth_ops[0];
+	}
+#endif
 	return NULL;
 }