bpf: use hwaddr for identification

3 files changed, 61 insertions, 23 deletions

diff --git a/bpf/bpf_bpfel.o b/bpf/bpf_bpfel.o
index 789c00f..d9a44b4 100644
--- a/bpf/bpf_bpfel.o
+++ b/bpf/bpf_bpfel.o
diff --git a/bpf/bpf_usage.c b/bpf/bpf_usage.c
index 5e505da..8b2343a 100644
--- a/bpf/bpf_usage.c
+++ b/bpf/bpf_usage.c
@@ -12,14 +12,14 @@ char __license[] SEC("license") = "GPL";
 struct {
 	__uint(type, BPF_MAP_TYPE_LRU_HASH);
 	__uint(max_entries, MAX_MAP_ENTRIES);
-	__type(key, __u32);   // source IPv4 address
+	__type(key, __u64);   // source mac address
 	__type(value, __u64); // no of bytes
 } ingress_ip4_usage_map SEC(".maps");
 
 struct {
 	__uint(type, BPF_MAP_TYPE_LRU_HASH);
 	__uint(max_entries, MAX_MAP_ENTRIES);
-	__type(key, __u32);   // destination IPv4 address
+	__type(key, __u64);   // destination mac address
 	__type(value, __u64); // no of bytes
 } egress_ip4_usage_map SEC(".maps");
 
@@ -28,31 +28,60 @@ typedef enum {
 	UPDATE_USAGE_EGRESS,
 } update_usage_t;
 
+static __always_inline __u64 nchar6_to_u64(unsigned char bytes[6])
+{
+	union {
+		char bytes[6];
+		__u64 i;
+	} ret;
+
+	ret.i = 0;
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	ret.bytes[0] = bytes[5];
+	ret.bytes[1] = bytes[4];
+	ret.bytes[2] = bytes[3];
+	ret.bytes[3] = bytes[2];
+	ret.bytes[4] = bytes[1];
+	ret.bytes[5] = bytes[0];
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	ret.bytes[0] = bytes[0];
+	ret.bytes[1] = bytes[1];
+	ret.bytes[2] = bytes[2];
+	ret.bytes[3] = bytes[3];
+	ret.bytes[4] = bytes[4];
+	ret.bytes[5] = bytes[5];
+#endif
+
+	return ret.i;
+}
+
 static __always_inline int update_usage(void *map, struct __sk_buff *skb,
 					update_usage_t traffic)
 {
-	__u32 ip4;
-	__u64 len, *usage;
+	__u64 mac, len, *usage;
 
 	void *data_end = (void *)(long)skb->data_end;
-	void *data = (void *)(long)skb->data;
-	struct iphdr *ip = data + sizeof(struct ethhdr);
+	struct ethhdr *eth = (void *)(long)skb->data;
 
-	if (skb->protocol != bpf_htons(ETH_P_IP))
+	if ((void *) (eth + 1) > data_end)
 		return TCX_PASS;
-	else if ((void *)(ip + 1) > data_end)
+
+	if (skb->protocol != bpf_htons(ETH_P_IP) &&
+	    skb->protocol != bpf_htons(ETH_P_IPV6)) {
 		return TCX_PASS;
+	}
 
-	if (traffic == UPDATE_USAGE_INGRESS)
-		ip4 = ip->saddr;
-	else
-		ip4 = ip->daddr;
 	len = skb->len - sizeof(struct ethhdr);
+	if (traffic == UPDATE_USAGE_INGRESS) {
+		mac = nchar6_to_u64(eth->h_source);
+	} else {
+		mac = nchar6_to_u64(eth->h_dest);
+	}
 
-	usage = bpf_map_lookup_elem(map, &ip4);
+	usage = bpf_map_lookup_elem(map, &mac);
 	if (!usage) {
 		/* no entry in the map for this IP address yet. */
-		bpf_map_update_elem(map, &ip4, &len, BPF_ANY);
+		bpf_map_update_elem(map, &mac, &len, BPF_ANY);
 	} else {
 		__sync_fetch_and_add(usage, len);
 	}
diff --git a/bpf/main.go b/bpf/main.go
index 4f1360e..c436534 100644
--- a/bpf/main.go
+++ b/bpf/main.go
@@ -3,7 +3,6 @@ package bpf
 import (
 	"context"
 	"errors"
-	"fmt"
 	"log"
 	"net"
 	"time"
@@ -20,7 +19,7 @@ type UsageStat struct {
 	ingress    uint64
 	egress     uint64
 }
-type UsageMap map[uint32]UsageStat
+type UsageMap map[uint64]UsageStat
 
 func Run(iface *net.Interface, queries *db.Queries, ctxDb context.Context) {
 	usageMap := make(UsageMap)
@@ -51,9 +50,9 @@ func Run(iface *net.Interface, queries *db.Queries, ctxDb context.Context) {
 	}
 	defer egressLink.Close()
 
-	bpfTicker := time.NewTicker(1 * time.Second)
+	bpfTicker := time.NewTicker(time.Second)
 	defer bpfTicker.Stop()
-	dbTicker := time.NewTicker(60 * time.Second)
+	dbTicker := time.NewTicker(time.Minute)
 	defer dbTicker.Stop()
 	for {
 		select {
@@ -95,7 +94,7 @@ func (usageMap UsageMap) updateDb(queries *db.Queries, ctxDb context.Context) er
 		}
 
 		err := queries.EnterUsage(ctxDb, db.EnterUsageParams{
-			Hardwareaddr: int32(key),
+			Hardwareaddr: int64(key),
 			Starttime: pgtype.Timestamp{
 				Time:  value.lastDbPush,
 				Valid: true,
@@ -104,8 +103,8 @@ func (usageMap UsageMap) updateDb(queries *db.Queries, ctxDb context.Context) er
 				Time:  value.lastSeen,
 				Valid: true,
 			},
-			Egress:  int32(value.egress),
-			Ingress: int32(value.ingress),
+			Egress:  int64(value.egress),
+			Ingress: int64(value.ingress),
 		})
 		if err != nil {
 			return err
@@ -119,14 +118,19 @@ func (usageMap UsageMap) updateDb(queries *db.Queries, ctxDb context.Context) er
 
 func (usageMap UsageMap) update(ingress *ebpf.Map, egress *ebpf.Map) error {
 	timeStart := time.Now()
-	batchKeys := make([]uint32, 4096)
+	batchKeys := make([]uint64, 4096)
 	batchValues := make([]uint64, 4096)
-	var key uint32
+	var key uint64
 
 	cursor := ebpf.MapBatchCursor{}
 	for {
 		_, err := ingress.BatchLookupAndDelete(&cursor, batchKeys, batchValues, nil)
 		for i := range batchKeys {
+			/* TODO: maybe BatchLookupAndDelete is not the best idea with mostly empty map */
+			if batchValues[i] == 0 {
+				continue
+			}
+
 			key = batchKeys[i]
 			usage, ok := usageMap[key]
 			if ok {
@@ -153,6 +157,11 @@ func (usageMap UsageMap) update(ingress *ebpf.Map, egress *ebpf.Map) error {
 	for {
 		_, err := egress.BatchLookupAndDelete(&cursor, batchKeys, batchValues, nil)
 		for i := range batchKeys {
+			/* TODO: maybe BatchLookupAndDelete is not the best idea with mostly empty map */
+			if batchValues[i] == 0 {
+				continue
+			}
+
 			key = batchKeys[i]
 			usage, ok := usageMap[key]
 			if ok {