/*
 *      Copyright (C) 2009 IBM Corp.
 *      This file is part of systemtap, and is free software.  You can
 *      redistribute it and/or modify it under the terms of the GNU General
 *      Public License (GPL); either version 2, or (at your option) any
 *      later version.
 *      
 *      Version 1.0     wilder@us.ibm.com     2009-07-06
 */

/* Global counter definitions for mib TCP_MIB. */

%{
#include <net/sock.h>
#include <linux/tcp.h>
#include <net/tcp_states.h>
#include <linux/skbuff.h>
#include <net/route.h>
%}

global ActiveOpens
global AttemptFails
global CurrEstab
global EstabResets
// global InErrs, this mib is not yet supported
global InSegs
global OutRsts
global OutSegs
global PassiveOpens
global RetransSegs

/**
 * sfunction tcpmib_get_state - Get a socket's state.
 *
 * Returns the sk_state from a struct sock.
 * @sk: Pointer to a struct sock.
 *
 */
function tcpmib_get_state:long (sk:long)
%{ /* pure */
	struct sock *sk = (struct sock *)(long)THIS->sk;
	THIS->__retvalue = kread(&(sk->sk_state));
	CATCH_DEREF_FAULT();
%}

/**
 * sfunction tcpmib_local_addr - Get the source address.
 *
 * Returns the saddr from a struct inet_sock.
 * @sk: Pointer to a struct inet_sock.
 *
 */
function tcpmib_local_addr:long(sk:long)
%{ /* pure */
        struct inet_sock *inet = (struct inet_sock *) (long) THIS->sk;
        THIS->__retvalue = ntohl(kread(&(inet->saddr)));
        CATCH_DEREF_FAULT();
%}

/**
 * sfunction tcpmib_remote_addr - Get the remote address.
 *
 * Returns the daddr from a struct inet_sock.
 * @sk: Pointer to a struct inet_sock.
 *
 */
function tcpmib_remote_addr:long(sk:long)
%{ /* pure */
        struct inet_sock *inet = (struct inet_sock *) (long) THIS->sk;
        THIS->__retvalue = ntohl(kread(&(inet->daddr)));
        CATCH_DEREF_FAULT();
%}

/**
 * sfunction tcpmib_local_port - Get the local port.
 *
 * Returns the sport from a struct inet_sock.
 * @sk: Pointer to a struct inet_sock.
 *
 */
function tcpmib_local_port:long(sk:long)
%{ /* pure */
        struct inet_sock *inet = (struct inet_sock *) (long) THIS->sk;
        THIS->__retvalue = ntohs(kread(&(inet->sport)));
        CATCH_DEREF_FAULT();
%}

/**
 * sfunction tcpmib_remote_port - Get the remote port.
 *
 * Returns the dport from a struct inet_sock.
 * @sk: Pointer to a struct inet_sock.
 *
 */
function tcpmib_remote_port:long(sk:long)
%{ /* pure */
        struct inet_sock *inet = (struct inet_sock *) (long) THIS->sk;
        THIS->__retvalue = ntohs(kread(&(inet->dport)));
        CATCH_DEREF_FAULT();
%}

/**
 * probe tcpmib.ActiveOpens - Count an active opening of a socket.
 * @sk:	Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: ActiveOpens
 * MIB: TCP_MIB_ACTIVEOPENS
 *
 */
probe
tcpmib.ActiveOpens=kernel.function("tcp_connect").return
{
	sk = $sk;
	op = 1;
	if ( $return ) next;
	key = tcpmib_filter_key(sk,op);
	if ( key ) ActiveOpens[key] += op;
}

/**
 * probe tcpmib.AttemptFails - Count a failed attempt to open a socket.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: AttemptFails
 * MIB: TCP_MIB_ATTEMPTFAILS
 *
 */
probe
tcpmib.AttemptFails=kernel.function("tcp_done")
{
	sk = $sk;
	state = tcpmib_get_state(sk);
	op = 1;

	TCP_SYN_SENT = 2;
	TCP_SYN_RECV = 3;
	if( state == TCP_SYN_SENT || state == TCP_SYN_RECV){
		key = tcpmib_filter_key(sk,op);
		if ( key ) AttemptFails[key] += op;
	}
}

/**
 * probe tcpmib.CurrEstab - Update the count of open sockets.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: CurrEstab
 * MIB: TCP_MIB_CURRESTAB
 *
 */
probe
tcpmib.CurrEstab=kernel.function("tcp_set_state")
{
	sk = $sk;
	state = $state;
	oldstate = tcpmib_get_state(sk);

	TCP_ESTABLISHED = 1;
	if ( oldstate == TCP_ESTABLISHED ) {
		op = -1;
		key = tcpmib_filter_key(sk,op);
		if ( key ) CurrEstab[key] += op;
	} else {
		if ( state == TCP_ESTABLISHED ) {
			op = 1;
			key = tcpmib_filter_key(sk,op);
			if ( key ) CurrEstab[key] += op;
		}
	}
}

/**
 * probe tcpmib.EstabResets - Count the reset of a socket.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: EstabResets
 * MIB: TCP_MIB_ESTABRESETS
 *
 */
probe
tcpmib.EstabResets=kernel.function("tcp_set_state")
{
	sk = $sk;
        state = $state;
        oldstate = tcpmib_get_state(sk);
	op = 1;

	TCP_CLOSE = 7;
	TCP_CLOSE_WAIT = 8;
	TCP_ESTABLISHED = 1;
	if ( ( state == TCP_CLOSE ) && 
	   (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) ){
        	key = tcpmib_filter_key(sk,op);
		if ( key ) EstabResets[key] += op;
	}
}

/**
 * probe tcpmib.InSegs - Count an incomming tcp segment.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: InSegs
 * MIB: TCP_MIB_INSEGS
 *
 */
probe
tcpmib.InSegs=kernel.function("__inet_lookup_established").return
{
        sk=$return
	op=1
	key = tcpmib_filter_key(sk,op);
	if ( key ) InSegs[key] += op;
}

/**
 * probe tcpmib.OutRsts - Count the sending of a reset packet.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: OutRsts
 * MIB: TCP_MIB_OUTRSTS
 *
 */
probe
tcpmib.OutRsts = 	tcpmib.OutRsts.A,
			tcpmib.OutRsts.B { }

function _rtn_local:long ()
%{
        THIS->__retvalue = RTN_LOCAL;
%}

function _is_reset:long (skb:long)
%{ /* pure */
        struct tcphdr *th;
        struct sk_buff *skb = (struct sk_buff *)(long)THIS->skb;

	#ifdef NET_SKBUFF_DATA_USES_OFFSET
		th = (struct tcphdr *)(kread(&(skb->network_header)) + kread(&(skb->head)));
	#else
		th = (struct tcphdr *)kread(&(skb->network_header));
	#endif
        THIS->__retvalue = th->rst;
        CATCH_DEREF_FAULT();
%}

function _tcpmib_input_route_type:long (skb:long)
{
%( kernel_v < "2.6.31" %?
	return __tcpmib_input_route_type_old(skb)
%:
	return __tcpmib_input_route_type_new(skb)
%)
}

function __tcpmib_input_route_type_old:long (skb:long)
%{ /* pure */
	struct rtable *rt;
	struct sk_buff *skb = (struct sk_buff *)(long)THIS->skb;
	rt = (struct rtable *)kread(&(skb->rtable));
	if ( rt )
		THIS->__retvalue = kread(&(rt->rt_type));
	else
		THIS->__retvalue = RTN_UNSPEC;
	CATCH_DEREF_FAULT();
%}

function __tcpmib_input_route_type_new:long (skb:long)
%{ /* pure */
	struct rtable *rt;
	struct sk_buff *skb = (struct sk_buff *)(long)THIS->skb;
	rt = (struct rtable *)kread(&(skb->_skb_dst));
	if ( rt )
		THIS->__retvalue = kread(&(rt->rt_type));
	else
		THIS->__retvalue = RTN_UNSPEC;
	CATCH_DEREF_FAULT();
%}

/*
 * note:
 * tcp_v4_send_reset may be called with a NULL sk.
 * This happens when sending a reset in response to a syn 
 * when no socket exists (for example the service is not running).
 * Without a socket we can't count the reset.
 */
probe
tcpmib.OutRsts.A=kernel.function("tcp_v4_send_reset")
{
        sk = $sk;
        skb = $skb
        op = 1;
        if ( _is_reset(skb) ) next
        if (_tcpmib_input_route_type($skb) != _rtn_local() )
                next;
        key = tcpmib_filter_key(sk,op);
        if ( key ) OutRsts[key] += op;
}

probe
tcpmib.OutRsts.B= kernel.function("tcp_send_active_reset")
{
	/* Almost correct,
	 * If alloc_skb() fails it incorrectly bumps TCP_MIB_OUTRSTS,
	 */
	sk = $sk;
	op = 1;
	key = tcpmib_filter_key(sk,op);
        if ( key ) OutRsts[key] += op;
}

/**
 * probe tcpmib.OutSegs - Count the sending of a TCP segment.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: OutSegs
 * MIB: TCP_MIB_OUTSEGS
 *
 */
probe
tcpmib.OutSegs=kernel.function("ip_queue_xmit").return
{
	if ( $return < 0 ) next;
	sk = $skb->sk;
	op = 1;
	
        //  Only count the events with protocol IPPROTO_TCP,6.
	iphdr = __get_skb_iphdr($skb);
        if( !(__ip_skb_proto(iphdr) == 6) ) next ;
	key = tcpmib_filter_key(sk,op);
	if ( key ) OutSegs[key] += op;
}

/**
 * probe tcpmib.PassiveOpens - Count the passive creation of a socket.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: PassiveOpens
 * MIB: TCP_MIB_PASSIVEOPENS
 *
 */
probe
tcpmib.PassiveOpens=kernel.function("tcp_v4_syn_recv_sock").return
{
        sk = $return;
        op = 1;
        if ( !sk ) next;
        key = tcpmib_filter_key(sk,op);
        if ( key ) PassiveOpens[key] += op;
}

/**
 * probe tcpmib.RetransSegs - Count the retransmission of a TCP segment.
 * @sk: Pointer to the struct sock being acted on.
 * @op: Value to be added to the counter (Operation). 
 *
 * Counter Name: RetransSegs
 * MIB: TCP_MIB_RETRANSSEGS
 *
 */
probe
tcpmib.RetransSegs=kernel.function("tcp_retransmit_skb").return
{
	sk = $sk;
	op = 1;
	if ( $return ) next;
	key = tcpmib_filter_key(sk,op);
	if ( key ) RetransSegs[key] += op;
}