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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, __u32); // source IPv4 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(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 int update_usage(void *map, struct __sk_buff *skb,
update_usage_t traffic)
{
__u32 ip4;
__u64 len, *usage;
void *data_end = (void *)(long)skb->data_end;
void *data = (void *)(long)skb->data;
struct iphdr *ip = data + sizeof(struct ethhdr);
if (skb->protocol != bpf_htons(ETH_P_IP))
return TCX_PASS;
else if ((void *)(ip + 1) > data_end)
return TCX_PASS;
if (traffic == UPDATE_USAGE_INGRESS)
ip4 = ip->saddr;
else
ip4 = ip->daddr;
len = skb->len - sizeof(struct ethhdr);
usage = bpf_map_lookup_elem(map, &ip4);
if (!usage) {
/* no entry in the map for this IP address yet. */
bpf_map_update_elem(map, &ip4, &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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