/* netfilter.stp - netfilter hook tapset
 *
 * Copyright (C) 2012, 2017-2018 Red Hat Inc.
 * <tapsetdescription>
 * This family of probe points provides a simple way to examine network traffic using the netfilter hooks mechanism.
 * </tapsetdescription>
 */

// See the BZ1546179 block comment in tapset/linux/networking.stp for
// an explanation of the try/catch statements around sk_buff structure
// accesses.

/* The below functionality is mostly inspired by tcp.stp and networking.stp. */

%{
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/netfilter_arp.h>
#include <linux/if_arp.h>
#include <net/ipv6.h>
#include <net/llc_pdu.h>
#include <linux/llc.h>
%}

# XXX: IPPROTO_* and NF_* constants should be secure globals -- needs PR10607
  # ... currently we use a hideous copypasta hack which defines them as
  # locals in each probe alias. Blegh

@__private30 function __mac_addr_to_string:string(addr:long) {
         return sprintf("%02x:%02x:%02x:%02x:%02x:%02x",
                        kernel_char(addr)&255, kernel_char(addr+1)&255,
                        kernel_char(addr+2)&255, kernel_char(addr+3)&255,
                        kernel_char(addr+4)&255, kernel_char(addr+5)&255)
}

@__private30 function __get_mac_addr:string(addr:long) {
         return __mac_addr_to_string(@cast(addr, "struct net_device", "kernel<linux/netdevice.h>")->dev_addr)
}

@__private30 function __get_skb_arphdr:long(addr:long)
{
        // The method is exactly the same as for an IP header:
        return __get_skb_iphdr(addr)
}

/* returns the bridge header for kernel >= 2.6.21 */
@__private30 function __get_skb_brhdr_new:long(skb:long)
%{ /* pure */
    struct sk_buff *skb;
    skb = (struct sk_buff *)(uintptr_t)STAP_ARG_skb;
    /* as done by skb_network_header() */
    #ifdef NET_SKBUFF_DATA_USES_OFFSET
        STAP_RETVALUE = (long)(kread(&(skb->head)) + kread(&(skb->network_header)) + sizeof(struct llc_pdu_un));
    #else
        STAP_RETVALUE = (long)(kread(&(skb->network_header)) + sizeof(struct llc_pdu_un));
    #endif
    CATCH_DEREF_FAULT();
%}

/* returns the bridge header for a given sk_buff structure */
@__private30 function __get_skb_brhdr:long(skb:long)
{
%( kernel_v < "2.6.21" %?
	brhdr = @cast(skb, "sk_buff")->mac->raw + %{ /* pure */ sizeof(struct llc_pdu_un) %}
	return brhdr
%:
	return __get_skb_brhdr_new(skb)
%)
}

/* returns llc_pdu_un for a given sk_buff structure */
@__private30 function __get_skb_llc:long(skb:long)
%{ /* pure */
    struct sk_buff *skb;
    skb = (struct sk_buff *)(uintptr_t)STAP_ARG_skb;
    /* as done by skb_network_header() */
    #ifdef NET_SKBUFF_DATA_USES_OFFSET
        STAP_RETVALUE = (long)(kread(&(skb->head)) + kread(&(skb->network_header)));
    #else
        STAP_RETVALUE = (long)kread(&(skb->network_header));
    #endif
    CATCH_DEREF_FAULT();
%}

@__private30 function __ip6_skb_proto:long(addr:long)
%{ /* pure */
   struct sk_buff *skb = (struct sk_buff *)(uintptr_t)STAP_ARG_addr;
   struct ipv6hdr *hdr;
   u8 nexthdr;

   /* We call deref() here to ensure the memory at the skb location
    * is valid to read, to avoid potential kernel panic calling ipv6_hdr(). */
   (void)kderef_buffer(NULL, skb, sizeof(struct sk_buff));
   hdr = ipv6_hdr(skb);
   nexthdr = kread(&(hdr->nexthdr));

   if (ipv6_ext_hdr(nexthdr)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0)
     long result = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);     
#else
     __be16 frag_offp;
     int extoff = (u8 *)(hdr + 1) - kread(&(skb->data));
     long result = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_offp);
#endif
     STAP_RETVALUE = result < 0 ? 0 : result;
   } else {
     STAP_RETVALUE = 0;
   }
   CATCH_DEREF_FAULT();
%}

private function __skb_nonlinear:long(addr:long)
%{ /* pure */
  struct sk_buff *skb = (struct sk_buff *)(uintptr_t)STAP_ARG_addr;
  STAP_RETVALUE = skb_is_nonlinear(skb);
%}

private function __skb_shinfo:long(addr:long)
%{ /* pure */
  struct sk_buff *skb = (struct sk_buff *)(uintptr_t)STAP_ARG_addr;
  STAP_RETVALUE = (uintptr_t)skb_end_pointer(skb);
%}

private function __skb_frag_size:long(addr:long, frag:long)
%{ /* pure */
  struct skb_shared_info *skb_shr = (struct skb_shared_info *)(uintptr_t)STAP_ARG_addr;
  skb_frag_t skb_frag = skb_shr->frags[STAP_ARG_frag];
  STAP_RETVALUE = skb_frag.size;
%}

private function __skb_frag_data_addr:long(addr:long, frag:long)
%{ /* pure */
  struct skb_shared_info *skb_shr = (struct skb_shared_info *)(uintptr_t)STAP_ARG_addr;
  const skb_frag_t *skb_frag = &skb_shr->frags[STAP_ARG_frag];
  STAP_RETVALUE = (uintptr_t)skb_frag_address_safe(skb_frag);
%}

private function __buffer_data:string(skb:long, str:long)
{
  length = @cast(skb, "struct sk_buff", "kernel<linux/skbuff.h>")->len
  data_length = @cast(skb, "struct sk_buff", "kernel<linux/skbuff.h>")->data_len
  skb_data = @cast(skb, "struct sk_buff", "kernel<linux/skbuff.h>")->data
  headlen = length - data_length /* skb_headlen() */
  data = ""
  if (str) {
    data = kernel_buffer_quoted(skb_data, headlen)
  } else {
    data = sprintf("%.*M", headlen, skb_data)
  }

  if (__skb_nonlinear(skb)) {
    shinfo = __skb_shinfo(skb)
    nr_frags = @cast(shinfo, "struct skb_shared_info",
                     "kernel<linux/skbuff.h>")->nr_frags
    for (i = 0; i < nr_frags; i++) {
      frag_size = __skb_frag_size(shinfo, i)
      frag_data_addr = __skb_frag_data_addr(shinfo, i)
      if (str) {
        data .= kernel_buffer_quoted(frag_data_addr, frag_size)
      } else {
        data .= sprintf("%.*M", frag_size, frag_data_addr)
      }
    }
  }
  return data
}

@define netfilter_common_setup(pf_name) %(
        pf = @pf_name

        /* XXX not relevant for netfilter.arp & netfilter.bridge probes */
        ipproto_tcp = @const("IPPROTO_TCP")
        ipproto_udp = @const("IPPROTO_UDP")

        /* from include/linux/netfilter.h: */
        nf_drop = 0
        nf_accept = 1
        nf_stolen = 2
        nf_queue = 3
        nf_repeat = 4
        nf_stop = 5

        indev = & @cast($in, "struct net_device", "kernel<linux/netdevice.h>")
        outdev = & @cast($out, "struct net_device", "kernel<linux/netdevice.h>")
        indev_name = kernel_string(indev->name, "")
        outdev_name = kernel_string(outdev->name, "")

        if (indev) {
           indev_mac_len = indev->addr_len
           in_mac = __get_mac_addr(indev)
        }
        if (outdev) {
           outdev_mac_len = outdev->addr_len
           out_mac = __get_mac_addr(outdev)
        }

	try {
	   length = @cast($skb, "struct sk_buff", "kernel<linux/skbuff.h>")->len
	} catch { }
	try { data_hex = __buffer_data($skb, 0) } catch { }
	try { data_str = __buffer_data($skb, 1) } catch { }
%)

@define netfilter_ip4_setup %(
        family = @const("AF_INET")
	try {
           iphdr = __get_skb_iphdr($skb)
           saddr = format_ipaddr(__ip_skb_saddr(iphdr), @const("AF_INET"))
           daddr = format_ipaddr(__ip_skb_daddr(iphdr), @const("AF_INET"))
           protocol = __ip_skb_proto(iphdr)
	} catch { }

        try {
	   tcphdr = __get_skb_tcphdr($skb)
	   if (protocol == ipproto_tcp) {
              dport = __tcp_skb_dport(tcphdr)
              sport = __tcp_skb_sport(tcphdr)
              urg = __tcp_skb_urg(tcphdr)
              ack = __tcp_skb_ack(tcphdr)
              psh = __tcp_skb_psh(tcphdr)
              rst = __tcp_skb_rst(tcphdr)
              syn = __tcp_skb_syn(tcphdr)
              fin = __tcp_skb_fin(tcphdr)
           }

           /* udphdr is in the same place where tcphdr would have been */
           udphdr = & @cast(tcphdr, "udphdr", "kernel<linux/udp.h>")
           if (protocol == ipproto_udp) {
              dport = ntohs(udphdr->dest)
              sport = ntohs(udphdr->source)
           }
	} catch { }
%)

@define netfilter_ip6_setup %(
        family = @const("AF_INET6")
	try {
           iphdr = &@cast(__get_skb_iphdr($skb), "ipv6hdr", "kernel<linux/ipv6.h>")
           saddr = format_ipaddr(&iphdr->saddr, @const("AF_INET6"))
           daddr = format_ipaddr(&iphdr->daddr, @const("AF_INET6"))
           protocol = __ip6_skb_proto($skb)
	} catch { }

	try {
           tcphdr = __get_skb_tcphdr($skb)
           if (protocol == ipproto_tcp) {
              dport = __tcp_skb_dport(tcphdr)
              sport = __tcp_skb_sport(tcphdr)
              urg = __tcp_skb_urg(tcphdr)
              ack = __tcp_skb_ack(tcphdr)
              psh = __tcp_skb_psh(tcphdr)
              rst = __tcp_skb_rst(tcphdr)
              syn = __tcp_skb_syn(tcphdr)
              fin = __tcp_skb_fin(tcphdr)
           }
   
           /* udphdr is in the same place where tcphdr would have been */
           udphdr = & @cast(tcphdr, "udphdr", "kernel<linux/udp.h>")
           if (protocol == ipproto_udp) {
              dport = ntohs(udphdr->dest)
              sport = ntohs(udphdr->source)
           }        
	} catch { }
%)

/**
 * probe netfilter.ip.pre_routing - Called before an IP packet is routed
 * @pf: Protocol family - either 'ipv4' or 'ipv6'
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @iphdr: Address of IP header
 * @protocol: Packet protocol from driver (ipv4 only)
 * @ipproto_tcp: Constant used to signify that the packet protocol is TCP
 * @ipproto_udp: Constant used to signify that the packet protocol is UDP
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 * @family: IP address family
 * @saddr: A string representing the source IP address
 * @daddr: A string representing the destination IP address
 * @sport: TCP or UDP source port (ipv4 only)
 * @dport: TCP or UDP destination port (ipv4 only)
 * @urg: TCP URG flag (if protocol is TCP; ipv4 only)
 * @ack: TCP ACK flag (if protocol is TCP; ipv4 only)
 * @psh: TCP PSH flag (if protocol is TCP; ipv4 only)
 * @rst: TCP RST flag (if protocol is TCP; ipv4 only)
 * @syn: TCP SYN flag (if protocol is TCP; ipv4 only)
 * @fin: TCP FIN flag (if protocol is TCP; ipv4 only)
 */
probe netfilter.ip.pre_routing = netfilter.ipv4.pre_routing,
        netfilter.ipv6.pre_routing
{
}

probe netfilter.ipv4.pre_routing
        = netfilter.hook("NF_INET_PRE_ROUTING").pf("NFPROTO_IPV4")
{
        @netfilter_common_setup("ipv4")
        @netfilter_ip4_setup
}


probe netfilter.ipv6.pre_routing
        = netfilter.hook("NF_IP6_PRE_ROUTING").pf("NFPROTO_IPV6")
{
        @netfilter_common_setup("ipv6")
        @netfilter_ip6_setup
}

/**
 * probe netfilter.ip.local_in - Called on an incoming IP packet addressed to the local computer
 * @pf: Protocol family -- either "ipv4" or "ipv6"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @iphdr: Address of IP header
 * @protocol: Packet protocol from driver (ipv4 only)
 * @ipproto_tcp: Constant used to signify that the packet protocol is TCP
 * @ipproto_udp: Constant used to signify that the packet protocol is UDP
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 * @family: IP address family
 * @saddr: A string representing the source IP address
 * @daddr: A string representing the destination IP address
 * @sport: TCP or UDP source port (ipv4 only)
 * @dport: TCP or UDP destination port (ipv4 only)
 * @urg: TCP URG flag (if protocol is TCP; ipv4 only)
 * @ack: TCP ACK flag (if protocol is TCP; ipv4 only)
 * @psh: TCP PSH flag (if protocol is TCP; ipv4 only)
 * @rst: TCP RST flag (if protocol is TCP; ipv4 only)
 * @syn: TCP SYN flag (if protocol is TCP; ipv4 only)
 * @fin: TCP FIN flag (if protocol is TCP; ipv4 only)
 */
probe netfilter.ip.local_in = netfilter.ipv4.local_in,
        netfilter.ipv6.local_in
{
}

probe netfilter.ipv4.local_in
        = netfilter.hook("NF_INET_LOCAL_IN").pf("NFPROTO_IPV4")
{
        @netfilter_common_setup("ipv4")
        @netfilter_ip4_setup
}


probe netfilter.ipv6.local_in
        = netfilter.hook("NF_IP6_LOCAL_IN").pf("NFPROTO_IPV6")
{
        @netfilter_common_setup("ipv6")
        @netfilter_ip6_setup
}

/**
 * probe netfilter.ip.forward - Called on an incoming IP packet addressed to some other computer
 * @pf: Protocol family -- either "ipv4" or "ipv6"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @iphdr: Address of IP header
 * @protocol: Packet protocol from driver (ipv4 only)
 * @ipproto_tcp: Constant used to signify that the packet protocol is TCP
 * @ipproto_udp: Constant used to signify that the packet protocol is UDP
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 * @family: IP address family
 * @saddr: A string representing the source IP address
 * @daddr: A string representing the destination IP address
 * @sport: TCP or UDP source port (ipv4 only)
 * @dport: TCP or UDP destination port (ipv4 only)
 * @urg: TCP URG flag (if protocol is TCP; ipv4 only)
 * @ack: TCP ACK flag (if protocol is TCP; ipv4 only)
 * @psh: TCP PSH flag (if protocol is TCP; ipv4 only)
 * @rst: TCP RST flag (if protocol is TCP; ipv4 only)
 * @syn: TCP SYN flag (if protocol is TCP; ipv4 only)
 * @fin: TCP FIN flag (if protocol is TCP; ipv4 only)
 */
probe netfilter.ip.forward = netfilter.ipv4.forward,
        netfilter.ipv6.forward
{
}

probe netfilter.ipv4.forward
        = netfilter.hook("NF_INET_FORWARD").pf("NFPROTO_IPV4")
{
        @netfilter_common_setup("ipv4")
        @netfilter_ip4_setup
}


probe netfilter.ipv6.forward
        = netfilter.hook("NF_IP6_FORWARD").pf("NFPROTO_IPV6")
{
        @netfilter_common_setup("ipv6")
        @netfilter_ip6_setup
}

/**
 * probe netfilter.ip.local_out - Called on an outgoing IP packet
 * @pf: Protocol family -- either "ipv4" or "ipv6"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @iphdr: Address of IP header
 * @protocol: Packet protocol from driver (ipv4 only)
 * @ipproto_tcp: Constant used to signify that the packet protocol is TCP
 * @ipproto_udp: Constant used to signify that the packet protocol is UDP
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 * @family: IP address family
 * @saddr: A string representing the source IP address
 * @daddr: A string representing the destination IP address
 * @sport: TCP or UDP source port (ipv4 only)
 * @dport: TCP or UDP destination port (ipv4 only)
 * @urg: TCP URG flag (if protocol is TCP; ipv4 only)
 * @ack: TCP ACK flag (if protocol is TCP; ipv4 only)
 * @psh: TCP PSH flag (if protocol is TCP; ipv4 only)
 * @rst: TCP RST flag (if protocol is TCP; ipv4 only)
 * @syn: TCP SYN flag (if protocol is TCP; ipv4 only)
 * @fin: TCP FIN flag (if protocol is TCP; ipv4 only)
 */
probe netfilter.ip.local_out = netfilter.ipv4.local_out,
        netfilter.ipv6.local_out
{
}

probe netfilter.ipv4.local_out
        = netfilter.hook("NF_INET_LOCAL_OUT").pf("NFPROTO_IPV4")
{
        @netfilter_common_setup("ipv4")
        @netfilter_ip4_setup
}

probe netfilter.ipv6.local_out
        = netfilter.hook("NF_IP6_LOCAL_OUT").pf("NFPROTO_IPV6")
{
        @netfilter_common_setup("ipv6")
        @netfilter_ip6_setup
}

/**
 * probe netfilter.ip.post_routing - Called immediately before an outgoing IP packet leaves the computer
 * @pf: Protocol family -- either "ipv4" or "ipv6"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @iphdr: Address of IP header
 * @protocol: Packet protocol from driver (ipv4 only)
 * @ipproto_tcp: Constant used to signify that the packet protocol is TCP
 * @ipproto_udp: Constant used to signify that the packet protocol is UDP
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 * @family: IP address family
 * @saddr: A string representing the source IP address
 * @daddr: A string representing the destination IP address
 * @sport: TCP or UDP source port (ipv4 only)
 * @dport: TCP or UDP destination port (ipv4 only)
 * @urg: TCP URG flag (if protocol is TCP; ipv4 only)
 * @ack: TCP ACK flag (if protocol is TCP; ipv4 only)
 * @psh: TCP PSH flag (if protocol is TCP; ipv4 only)
 * @rst: TCP RST flag (if protocol is TCP; ipv4 only)
 * @syn: TCP SYN flag (if protocol is TCP; ipv4 only)
 * @fin: TCP FIN flag (if protocol is TCP; ipv4 only)
 */
probe netfilter.ip.post_routing = netfilter.ipv4.post_routing,
        netfilter.ipv6.local_out
{
}

probe netfilter.ipv4.post_routing
        = netfilter.hook("NF_INET_POST_ROUTING").pf("NFPROTO_IPV4")
{
        @netfilter_common_setup("ipv4")
        @netfilter_ip4_setup
}


probe netfilter.ipv6.post_routing
        = netfilter.hook("NF_IP6_POST_ROUTING").pf("NFPROTO_IPV6")
{
        @netfilter_common_setup("ipv6")
        @netfilter_ip6_setup
}

@define netfilter_arp_setup %(
# XXX: include functionality to parse ARP packet contents
	try {
           arphdr = & @cast(__get_skb_arphdr($skb), "struct arphdr", "kernel<linux/if_arp.h>")
           family = @const("NF_ARP") // from linux/netfilter_arp.h
           ar_hrd = ntohs(arphdr->ar_hrd)
           ar_pro = ntohs(arphdr->ar_pro)
           ar_hln = arphdr->ar_hln
           ar_pln = arphdr->ar_pln
           ar_op = ntohs(arphdr->ar_op)
	} catch { }

        ar_data = arphdr + 8
        if (ar_hrd == 0x001 && ar_pro == 0x800) {
           /* additional info available for most common (Ethernet+IP) case: */
           ar_sha = __mac_addr_to_string(ar_data)
           ar_sip = format_ipaddr(kernel_int(ar_data + 6), @const("AF_INET"))
           ar_tha = __mac_addr_to_string(ar_data + 10)
           ar_tip =  format_ipaddr(kernel_int(ar_data + 16), @const("AF_INET"))
        }
        /* XXX support for additional cases? */
%)

/**
 * probe netfilter.arp.in -- Called for each incoming ARP packet
 * @pf: Protocol family -- always "arp"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @arphdr: Address of ARP header
 * @ar_hrd: Format of hardware address
 * @ar_pro: Format of protocol address
 * @ar_hln: Length of hardware address
 * @ar_pln: Length of protocol address
 * @ar_op: ARP opcode (command)
 * @ar_data: Address of ARP packet data region (after the header)
 * @ar_sha: Ethernet+IP only (ar_pro==0x800): source hardware (MAC) address 
 * @ar_sip: Ethernet+IP only (ar_pro==0x800): source IP address
 * @ar_tha: Ethernet+IP only (ar_pro==0x800): target hardware (MAC) address
 * @ar_tip: Ethernet+IP only (ar_pro==0x800): target IP address
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.arp.in = netfilter.hook("NF_ARP_IN").pf("NFPROTO_ARP")
{
        @netfilter_common_setup("arp")
        @netfilter_arp_setup
}


/**
 * probe netfilter.arp.out -- Called for each outgoing ARP packet
 * @pf: Protocol family -- always "arp"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @arphdr: Address of ARP header
 * @ar_hrd: Format of hardware address
 * @ar_pro: Format of protocol address
 * @ar_hln: Length of hardware address
 * @ar_pln: Length of protocol address
 * @ar_op: ARP opcode (command)
 * @ar_data: Address of ARP packet data region (after the header)
 * @ar_sha: Ethernet+IP only (ar_pro==0x800): source hardware (MAC) address 
 * @ar_sip: Ethernet+IP only (ar_pro==0x800): source IP address
 * @ar_tha: Ethernet+IP only (ar_pro==0x800): target hardware (MAC) address
 * @ar_tip: Ethernet+IP only (ar_pro==0x800): target IP address
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.arp.out = netfilter.hook("NF_ARP_OUT").pf("NFPROTO_ARP")
{
        @netfilter_common_setup("arp")
        @netfilter_arp_setup
}

/**
 * probe netfilter.arp.forward -- Called for each ARP packet to be forwarded
 * @pf: Protocol family -- always "arp"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @arphdr: Address of ARP header
 * @ar_hrd: Format of hardware address
 * @ar_pro: Format of protocol address
 * @ar_hln: Length of hardware address
 * @ar_pln: Length of protocol address
 * @ar_op: ARP opcode (command)
 * @ar_data: Address of ARP packet data region (after the header)
 * @ar_sha: Ethernet+IP only (ar_pro==0x800): source hardware (MAC) address 
 * @ar_sip: Ethernet+IP only (ar_pro==0x800): source IP address
 * @ar_tha: Ethernet+IP only (ar_pro==0x800): target hardware (MAC) address
 * @ar_tip: Ethernet+IP only (ar_pro==0x800): target IP address
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.arp.forward = netfilter.hook("NF_ARP_FORWARD").pf("NFPROTO_ARP")
{
        @netfilter_common_setup("arp")
        @netfilter_arp_setup
}

@define netfilter_bridge_setup %(
	try {
           llcpdu = &@cast(__get_skb_llc($skb), "struct llc_pdu_un",
			   "kernel<net/llc_pdu.h>")
           brhdr = __get_skb_brhdr($skb)
	} catch { }
        llcproto_stp = @const("LLC_SAP_BSPAN") // from linux/llc.h

        if (llcpdu->dsap == llcproto_stp && llcpdu->ssap == llcproto_stp) {
            protocol = llcproto_stp
            br_prid = ntohs(kernel_short(brhdr))
            br_vid = kernel_char(brhdr + 2)
            br_type = kernel_char(brhdr + 3)
            br_flags = kernel_char(brhdr + 4)
            br_rid = kernel_long(brhdr + 5)
            br_rmac = __mac_addr_to_string(brhdr + 7)
            br_cost = ntohl(kernel_int(brhdr + 13))
            br_bid = kernel_long(brhdr + 17)
            br_mac = __mac_addr_to_string(brhdr + 19)
            br_poid = ntohs(kernel_short(brhdr + 25))
            br_msg = ntohs(kernel_short(brhdr + 27))
            br_max = ntohs(kernel_short(brhdr + 29))
            br_htime = ntohs(kernel_short(brhdr + 31))
            br_fd = ntohs(kernel_short(brhdr + 33))
        }
%)

/**
 * probe netfilter.bridge.pre_routing -- Called before a bridging packet is routed
 * @pf: Protocol family -- always "bridge"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @llcpdu: Address of LLC Protocol Data Unit
 * @brhdr: Address of bridge header
 * @llcproto_stp: Constant used to signify Bridge Spanning Tree Protocol packet
 * @protocol: Packet protocol
 * @br_prid: Protocol identifier
 * @br_vid: Protocol version identifier
 * @br_type: BPDU type
 * @br_flags: BPDU flags
 * @br_rid: Identity of root bridge
 * @br_rmac: Root bridge MAC address
 * @br_cost: Total cost from transmitting bridge to root
 * @br_bid: Identity of bridge
 * @br_mac: Bridge MAC address
 * @br_poid: Port identifier
 * @br_msg: Message age in 1/256 secs
 * @br_max: Max age in 1/256 secs
 * @br_htime: Hello time in 1/256 secs
 * @br_fd: Forward delay in 1/256 secs
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.bridge.pre_routing
        = netfilter.hook("NF_BR_PRE_ROUTING").pf("NFPROTO_BRIDGE")
{
        @netfilter_common_setup("bridge")
        @netfilter_bridge_setup
}

/**
 * probe netfilter.bridge.local_in - Called on a bridging packet destined for the local computer
 * @pf: Protocol family -- always "bridge"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @llcpdu: Address of LLC Protocol Data Unit
 * @brhdr: Address of bridge header
 * @llcproto_stp: Constant used to signify Bridge Spanning Tree Protocol packet
 * @protocol: Packet protocol
 * @br_prid: Protocol identifier
 * @br_vid: Protocol version identifier
 * @br_type: BPDU type
 * @br_flags: BPDU flags
 * @br_rid: Identity of root bridge
 * @br_rmac: Root bridge MAC address
 * @br_cost: Total cost from transmitting bridge to root
 * @br_bid: Identity of bridge
 * @br_mac: Bridge MAC address
 * @br_poid: Port identifier
 * @br_msg: Message age in 1/256 secs
 * @br_max: Max age in 1/256 secs
 * @br_htime: Hello time in 1/256 secs
 * @br_fd: Forward delay in 1/256 secs
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.bridge.local_in
        = netfilter.hook("NF_BR_LOCAL_IN").pf("NFPROTO_BRIDGE")
{
        @netfilter_common_setup("bridge")
        @netfilter_bridge_setup
}

/**
 * probe netfilter.bridge.forward - Called on an incoming bridging packet destined for some other computer
 * @pf: Protocol family -- always "bridge"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @llcpdu: Address of LLC Protocol Data Unit
 * @brhdr: Address of bridge header
 * @llcproto_stp: Constant used to signify Bridge Spanning Tree Protocol packet
 * @protocol: Packet protocol
 * @br_prid: Protocol identifier
 * @br_vid: Protocol version identifier
 * @br_type: BPDU type
 * @br_flags: BPDU flags
 * @br_rid: Identity of root bridge
 * @br_rmac: Root bridge MAC address
 * @br_cost: Total cost from transmitting bridge to root
 * @br_bid: Identity of bridge
 * @br_mac: Bridge MAC address
 * @br_poid: Port identifier
 * @br_msg: Message age in 1/256 secs
 * @br_max: Max age in 1/256 secs
 * @br_htime: Hello time in 1/256 secs
 * @br_fd: Forward delay in 1/256 secs
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.bridge.forward
        = netfilter.hook("NF_BR_FORWARD").pf("NFPROTO_BRIDGE")
{
        @netfilter_common_setup("bridge")
        @netfilter_bridge_setup
}

/**
 * probe netfilter.bridge.local_out - Called on a bridging packet coming from a local process
 * @pf: Protocol family -- always "bridge"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @llcpdu: Address of LLC Protocol Data Unit
 * @brhdr: Address of bridge header
 * @llcproto_stp: Constant used to signify Bridge Spanning Tree Protocol packet
 * @protocol: Packet protocol
 * @br_prid: Protocol identifier
 * @br_vid: Protocol version identifier
 * @br_type: BPDU type
 * @br_flags: BPDU flags
 * @br_rid: Identity of root bridge
 * @br_rmac: Root bridge MAC address
 * @br_cost: Total cost from transmitting bridge to root
 * @br_bid: Identity of bridge
 * @br_mac: Bridge MAC address
 * @br_poid: Port identifier
 * @br_msg: Message age in 1/256 secs
 * @br_max: Max age in 1/256 secs
 * @br_htime: Hello time in 1/256 secs
 * @br_fd: Forward delay in 1/256 secs
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.bridge.local_out
        = netfilter.hook("NF_BR_LOCAL_OUT").pf("NFPROTO_BRIDGE")
{
        @netfilter_common_setup("bridge")
        @netfilter_bridge_setup
}

/**
 * probe netfilter.bridge.post_routing -- Called before a bridging packet hits the wire
 * @pf: Protocol family -- always "bridge"
 * @indev: Address of net_device representing input device, 0 if unknown
 * @outdev: Address of net_device representing output device, 0 if unknown
 * @indev_name: Name of network device packet was received on (if known)
 * @outdev_name: Name of network device packet will be routed to (if known)
 * @llcpdu: Address of LLC Protocol Data Unit
 * @brhdr: Address of bridge header
 * @llcproto_stp: Constant used to signify Bridge Spanning Tree Protocol packet
 * @protocol: Packet protocol
 * @br_prid: Protocol identifier
 * @br_vid: Protocol version identifier
 * @br_type: BPDU type
 * @br_flags: BPDU flags
 * @br_rid: Identity of root bridge
 * @br_rmac: Root bridge MAC address
 * @br_cost: Total cost from transmitting bridge to root
 * @br_bid: Identity of bridge
 * @br_mac: Bridge MAC address
 * @br_poid: Port identifier
 * @br_msg: Message age in 1/256 secs
 * @br_max: Max age in 1/256 secs
 * @br_htime: Hello time in 1/256 secs
 * @br_fd: Forward delay in 1/256 secs
 * @length: The length of the packet buffer contents, in bytes
 * @data_str: A string representing the packet buffer contents
 * @data_hex: A hexadecimal string representing the packet buffer contents
 * @nf_drop: Constant used to signify a 'drop' verdict
 * @nf_accept: Constant used to signify an 'accept' verdict
 * @nf_stolen: Constant used to signify a 'stolen' verdict
 * @nf_queue: Constant used to signify a 'queue' verdict
 * @nf_repeat: Constant used to signify a 'repeat' verdict
 * @nf_stop: Constant used to signify a 'stop' verdict
 */
probe netfilter.bridge.post_routing
        = netfilter.hook("NF_BR_POST_ROUTING").pf("NFPROTO_BRIDGE")
{
        @netfilter_common_setup("bridge")
        @netfilter_bridge_setup
}