95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
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package ebpf
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/*
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <linux/unistd.h>
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#include <linux/bpf.h>
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// See the bpf man page for details on the following functions
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static int bpf(enum bpf_cmd cmd, union bpf_attr *attr, unsigned int size)
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{
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return syscall(__NR_bpf, cmd, attr, size);
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}
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static int bpf_create_map(
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enum bpf_map_type map_type, unsigned int key_size, unsigned int value_size,
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unsigned int max_entries)
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{
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union bpf_attr attr = {
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.map_type = map_type,
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.key_size = key_size,
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.value_size = value_size,
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.max_entries = max_entries};
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return bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
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}
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int bpf_get_next_key(int fd, const void *key, void *next_key)
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{
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union bpf_attr attr = {
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.map_fd = fd,
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.key = (__u64) (unsigned long) key,
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.next_key = (__u64) (unsigned long) next_key};
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return bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
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}
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int bpf_lookup_elem(int fd, const void *key, void *value)
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{
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union bpf_attr attr = {
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.map_fd = fd,
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.key = (__u64) (unsigned long) key,
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.value = (__u64) (unsigned long) value,
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};
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return bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
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}
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*/
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import "C"
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import (
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"fmt"
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"syscall"
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"unsafe"
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)
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// CreateMap creates an eBPF map from int->uint64. The file descriptor of the
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// created map is returned.
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func CreateMap() (int, error) {
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mapFD := C.bpf_create_map(C.BPF_MAP_TYPE_HASH, 4, 8, 64)
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return int(mapFD), nil
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}
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// GetMap gets the key/value pairs from the specified eBPF map as a Go map
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func GetMap(mapFD int) (map[int]uint64, error) {
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retMap := make(map[int]uint64)
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mapFDC := C.int(mapFD)
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keyC := C.int(0)
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nextKeyC := C.int(0)
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valC := C.uint64_t(0)
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for {
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r, errno := C.bpf_get_next_key(mapFDC, unsafe.Pointer(&keyC), unsafe.Pointer(&nextKeyC))
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if r == -1 {
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if errno == syscall.ENOENT {
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// The provided key was the last element. We're done iterating.
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return retMap, nil
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}
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return nil, fmt.Errorf("bpf_get_next_key failed with errno %d", errno)
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}
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r = C.bpf_lookup_elem(mapFDC, unsafe.Pointer(&nextKeyC), unsafe.Pointer(&valC))
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if r == -1 {
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return nil, fmt.Errorf("bpf_lookup_elem failed")
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}
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retMap[int(nextKeyC)] = uint64(valC)
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keyC = nextKeyC
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}
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}
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