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Filename : ip.stp
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// IP tapset
//
// Copyright (C) 2009, IBM Inc.
// Copyright (C) 2010-2018 Red Hat Inc.
//
// Author : Breno Leitao <leitao@linux.vnet.ibm.com>
//
// This file is free software.  You can redistribute it and/or modify it under
// the terms of the GNU General Public License (GPL), version 2.
//
// Based on previous work done by Arnaldo Carvalho de Melo <acme@redhat.com>

%{
#include <linux/skbuff.h>
#include <linux/socket.h>		// For AF_INET & AF_INET6
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#include <linux/types.h>
#include <linux/in6.h>
#endif /* CONFIG_IPV6 || CONFIG_IPV6_MODULE */
%}

/**
 * sfunction format_ipaddr - Returns a string representation for an IP address
 *
 * @addr: the IP address
 * @family: the IP address family (either AF_INET or AF_INET6)
 */
function format_ipaddr:string (addr:long, family:long)
%{ /* pure */
	if (STAP_ARG_family == AF_INET) {
		__be32 ip = (__be32)STAP_ARG_addr;
#ifndef NIPQUAD_FMT			// kver >= 2.6.36
		snprintf(STAP_RETVALUE, MAXSTRINGLEN, "%pI4", &ip);
#else
		snprintf(STAP_RETVALUE, MAXSTRINGLEN, NIPQUAD_FMT,
			 NIPQUAD(ip));
#endif
	}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	else if (STAP_ARG_family == AF_INET6) {
		struct in6_addr *ipv6 = (struct in6_addr *)(uintptr_t)STAP_ARG_addr;
		// We need to derefence the memory safely from the
		// address passed to us that contains the IPv6 address.
		// However, kderef()/kread() only handle data with a
		// size of 1, 2, 4, or 8.  So, we'll use
		// kderef_buffer() which goes byte by byte.
		kderef_buffer(NULL, ipv6, sizeof(struct in6_addr));
#ifndef NIP6_FMT			// kver >= 2.6.36
		snprintf(STAP_RETVALUE, MAXSTRINGLEN, "%pI6", ipv6);
#else
		snprintf(STAP_RETVALUE, MAXSTRINGLEN, NIP6_FMT, NIP6(*ipv6));
#endif
	}
#endif /* CONFIG_IPV6 || CONFIG_IPV6_MODULE */
	else
		strlcpy(STAP_RETVALUE, "*unknown address family*",
			MAXSTRINGLEN);
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	CATCH_DEREF_FAULT();
#endif /* CONFIG_IPV6 || CONFIG_IPV6_MODULE */
%}

/**
 * sfunction ip_ntop - Returns a string representation for an IPv4 address
 *
 * @addr: the IPv4 address represented as an integer
 */
function ip_ntop:string (addr:long)
{
	return format_ipaddr(addr, @const("AF_INET"))
}

/*
 * Return the source IP address for a given sock.
 *
 * Note that the probes that use this function typically get a 'struct
 * sock' pointer, not a 'struct inet_sock' pointer.  This is expected.
 * To use a 'struct sock' pointer, you typically call inet_sk() on the
 * pointer, which just returns the pointer (since the 1st member of
 * 'struct inet_sock' is a 'struct sock').
 */

function __ip_sock_saddr:long (sock:long)
{
    family = @inet_sock_cast(sock)->sk->__sk_common->skc_family
    if (family == @const("AF_INET")) {
	return @choose_defined(@inet_sock_cast(sock)->inet_saddr, # kernel >= 2.6.33
		@choose_defined(@inet_sock_cast(sock)->saddr, # kernel >= 2.6.11
		    @inet_sock_cast(sock)->inet->saddr))
    }
%( CONFIG_IPV6 == "[ym]" %?
    else if (family == @const("AF_INET6")) {
	return (&@inet_sock_cast(sock)->pinet6->saddr)
    }
%)
    return 0
}

/* return the destination IP address for a given sock */
function __ip_sock_daddr:long (sock:long)
{
    family = @inet_sock_cast(sock)->sk->__sk_common->skc_family
    if (family == @const("AF_INET")) {
	return @choose_defined(@inet_sock_cast(sock)->sk->__sk_common->skc_daddr, # kernel >= 2.6.38
		@choose_defined(@inet_sock_cast(sock)->inet_daddr, # kernel >= 2.6.33
		    @choose_defined(@inet_sock_cast(sock)->daddr, # kernel >= 2.6.11
			@inet_sock_cast(sock)->inet->daddr)))
    }
%( CONFIG_IPV6 == "[ym]" %?
    else if (family == @const("AF_INET6")) {
	return @choose_defined(&@inet_sock_cast(sock)->sk->__sk_common->skc_v6_daddr,
			       &@inet_sock_cast(sock)->pinet6->daddr)
    }
%)
    return 0
}

/* return the IP address family for a given sock */
function __ip_sock_family:long (sock:long)
{
    return (@inet_sock_cast(sock)->sk->__sk_common->skc_family)
}

/* Get the IP header from a sk_buff struct */
function __get_skb_iphdr:long(skb:long)
%( kernel_v < "2.6.21" %?
{
  iphdr = @cast(skb, "sk_buff", "kernel<linux/skbuff.h>")->nh->raw
	return iphdr
}
%:
%{ /* pure */
	struct sk_buff *skb;
	skb = (struct sk_buff *)(uintptr_t)STAP_ARG_skb;

	/* We used to have our own version of skb_network_header()
	 * here, but it has changed too much over time to keep up with
	 * it. So, instead we'll make sure the entire skb is safe to
	 * read, then call the real skb_network_header(). */
	kderef_buffer(NULL, skb, sizeof(struct sk_buff));
	STAP_RETVALUE = (long)skb_network_header(skb);
	CATCH_DEREF_FAULT();
%}
%)

# Here's an explanation of the @cast() 3rd argument here. In newer
# kernels, the "iphdr" structure is in <uapi/linux/ip.h>. But in RHEL6
# that structure is in <linux/ip.h> and <uapi/linux/ip.h> doesn't
# exist. So, we can't do "kernel<linux/ip.h><uapi/linux/ip.h>". So, we
# list each header file separately.

@define iphdr_cast(ptr) %(
  @cast(@ptr, "iphdr", "kernel<linux/ip.h>:kernel<uapi/linux/ip.h>")
%)

/* return the source next layer protocol for a given sk_buff structure */
function __ip_skb_proto:long (iphdr)
{
  return @iphdr_cast(iphdr)->protocol
}

/* return the source IP address for a given sk_buff structure */
function __ip_skb_saddr:long (iphdr)
{
  return @iphdr_cast(iphdr)->saddr
}

/* return the destination IP address for a given skb */
function __ip_skb_daddr:long (iphdr)
{
  return @iphdr_cast(iphdr)->daddr
}