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#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <bpf/bpf_endian.h>
#include <bpf/bpf_helpers.h>
#define MAX_MAP_ENTRIES 4096
char __license[] SEC("license") = "GPL";
struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__uint(max_entries, MAX_MAP_ENTRIES);
__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, __u64); // destination mac address
__type(value, __u64); // no of bytes
} egress_ip4_usage_map SEC(".maps");
typedef enum {
UPDATE_USAGE_INGRESS,
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)
{
__u64 mac, len, *usage;
void *data_end = (void *)(long)skb->data_end;
struct ethhdr *eth = (void *)(long)skb->data;
if ((void *) (eth + 1) > data_end)
return TCX_PASS;
if (skb->protocol != bpf_htons(ETH_P_IP) &&
skb->protocol != bpf_htons(ETH_P_IPV6)) {
return TCX_PASS;
}
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, &mac);
if (!usage) {
/* no entry in the map for this IP address yet. */
bpf_map_update_elem(map, &mac, &len, BPF_ANY);
} else {
__sync_fetch_and_add(usage, len);
}
return TCX_PASS;
}
SEC("tc")
int ingress_func(struct __sk_buff *skb)
{
return update_usage(&ingress_ip4_usage_map, skb, UPDATE_USAGE_INGRESS);
}
SEC("tc")
int egress__func(struct __sk_buff *skb)
{
return update_usage(&egress_ip4_usage_map, skb, UPDATE_USAGE_EGRESS);
}
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