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.