NAME
    `Linux::SocketFilter' - interface to Linux's socket packet filtering

DESCRIPTION
    This module contains the constants and structure definitions to use
    Linux's socket packet filtering mechanism.

CONSTANTS
    The following constants are exported:

  Socket Options
     SO_ATTACH_FILTER SO_DETACH_FILTER

  BPF Instructions
     BPF_LD BPF_LDX BPF_ST BPF_STX BPF_ALU BPF_JMP BPF_RET BPF_MISC
     BPF_W BPF_H BPF_B BPF_IMM BPF_ABS BPF_IND BPF_MEM PBF_LEN BPF_MSH
     BPF_ADD BPF_SUB BPF_MUL BPF_DIV BPF_OR BPF_AND BPF_LSH BPF_RSH BPF_NEG
     BPF_JA BPF_JEQ BPF_JGT BPF_JGE BPF_JSET
     BPF_K BPF_X BPF_A BPF_TAX BPF_TXA

    This entire set of constants is also exported under the tag name `:bpf'.

  Linux BPF Extension Packet Addresses
     SKF_AD_OFF SKF_AD_PROTOCOL SKF_AD_PKTTYPE SKF_AD_IFINDEX
     SKF_NET_OFF SKF_LL_OFF

STRUCTURE FUNCTIONS
  $buffer = pack_sock_filter( $code, $jt, $jf, $k )
  ( $code, $jt, $jf, $k ) = unpack_sock_filter( $buffer )
    Pack or unpack a single BPF instruction.

SOCKET FUNCTIONS
  attach_filter( $sock, $filter )
    Attaches the given filter program to the given socket. The program
    should be a string formed by concatenating multiple calls to
    `pack_sock_filter()' to build the filter program.

  detach_filter( $sock )
    Detaches the current filter from the socket, returning it to accepting
    all packets.

AUTHOR
    Paul Evans <leonerd@leonerd.org.uk>

