NAME
bpf —
Berkeley Packet Filter kernel
interface
SYNOPSIS
#include <sys/mbuf.h>
#include <net/bpf.h>
DESCRIPTION
bpf is called via an operations vector described by the
following struct:
struct bpf_ops {
void (*bpf_attach)(struct ifnet *, u_int, u_int, struct bpf_if **);
void (*bpf_detach)(struct ifnet *);
void (*bpf_change_type)(struct ifnet *, u_int, u_int);
void (*bpf_tap)(struct bpf_if *, u_char *, u_int);
void (*bpf_mtap)(struct bpf_if *, struct mbuf *);
void (*bpf_mtap2)(struct bpf_if *, void *, u_int, struct mbuf *);
void (*bpf_mtap_af)(struct bpf_if *, uint32_t, struct mbuf *);
void (*bpf_mtap_et)(struct bpf_if *, uint16_t, struct mbuf *);
void (*bpf_mtap_sl_in)(struct bpf_if *, u_char *, struct mbuf **);
void (*bpf_mtap_sl_out)(struct bpf_if *, u_char *, struct mbuf *);
};
This vector is found from
struct bpf_ops *
bpf_ops. It is either a “stub”
implementation or a real implementation, depending on whether
bpf is absent or present in the kernel, respectively.
CODE REFERENCES
The
bpf implementation is located in
sys/net/bpf.c, the stub implementation is in
sys/net/bpf_stub.c, and
sys/net/bpf.h
describes the interface.