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/* $Id: IPv4Pool.cpp $ */
/** @file
* DHCP server - A pool of IPv4 addresses.
*/
/*
* Copyright (C) 2017-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* SPDX-License-Identifier: GPL-3.0-only
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include "DhcpdInternal.h"
#include <iprt/errcore.h>
#include "IPv4Pool.h"
int IPv4Pool::init(const IPv4Range &aRange) RT_NOEXCEPT
{
AssertReturn(aRange.isValid(), VERR_INVALID_PARAMETER);
m_range = aRange;
try
{
m_pool.insert(m_range);
}
catch (std::bad_alloc &)
{
return VERR_NO_MEMORY;
}
return VINF_SUCCESS;
}
int IPv4Pool::init(RTNETADDRIPV4 aFirstAddr, RTNETADDRIPV4 aLastAddr) RT_NOEXCEPT
{
return init(IPv4Range(aFirstAddr, aLastAddr));
}
/**
* Internal worker for inserting a range into the pool of available addresses.
*
* @returns IPRT status code (asserted).
* @param a_Range The range to insert.
*/
int IPv4Pool::i_insert(const IPv4Range &a_Range) RT_NOEXCEPT
{
/*
* Check preconditions. Asserting because nobody checks the return code.
*/
AssertReturn(m_range.isValid(), VERR_INVALID_STATE);
AssertReturn(a_Range.isValid(), VERR_INVALID_PARAMETER);
AssertReturn(m_range.contains(a_Range), VERR_INVALID_PARAMETER);
/*
* Check that the incoming range doesn't overlap with existing ranges in the pool.
*/
it_t itHint = m_pool.upper_bound(IPv4Range(a_Range.LastAddr)); /* successor, insertion hint */
#if 0 /** @todo r=bird: This code is wrong. It has no end() check for starters. Since the method is
* only for internal consumption, I've replaced it with a strict build assertion. */
if (itHint != m_pool.begin())
{
it_t prev(itHint);
--prev;
if (a_Range.FirstAddr <= prev->LastAddr)
{
LogRel(("%08x-%08x conflicts with %08x-%08x\n",
a_Range.FirstAddr, a_Range.LastAddr,
prev->FirstAddr, prev->LastAddr));
return VERR_INVALID_PARAMETER;
}
}
#endif
#ifdef VBOX_STRICT
for (it_t it2 = m_pool.begin(); it2 != m_pool.end(); ++it2)
AssertMsg(it2->LastAddr < a_Range.FirstAddr || it2->FirstAddr > a_Range.LastAddr,
("%08RX32-%08RX32 conflicts with %08RX32-%08RX32\n",
a_Range.FirstAddr, a_Range.LastAddr, it2->FirstAddr, it2->LastAddr));
#endif
/*
* No overlaps, insert it.
*/
try
{
m_pool.insert(itHint, a_Range);
}
catch (std::bad_alloc &)
{
return VERR_NO_MEMORY;
}
return VINF_SUCCESS;
}
/**
* Allocates an available IPv4 address from the pool.
*
* @returns Non-zero network order IPv4 address on success, zero address
* (0.0.0.0) on failure.
*/
RTNETADDRIPV4 IPv4Pool::allocate()
{
RTNETADDRIPV4 RetAddr;
if (!m_pool.empty())
{
/* Grab the first address in the pool: */
it_t itBeg = m_pool.begin();
RetAddr.u = RT_H2N_U32(itBeg->FirstAddr);
if (itBeg->FirstAddr == itBeg->LastAddr)
m_pool.erase(itBeg);
else
{
/* Trim the entry (re-inserting it): */
IPv4Range trimmed = *itBeg;
trimmed.FirstAddr += 1;
Assert(trimmed.FirstAddr <= trimmed.LastAddr);
m_pool.erase(itBeg);
try
{
m_pool.insert(trimmed);
}
catch (std::bad_alloc &)
{
/** @todo r=bird: Theortically the insert could fail with a bad_alloc and we'd
* drop a range of IP address. It would be nice if we could safely modify itBit
* without having to re-insert it. The author of this code (not bird) didn't
* seem to think this safe?
*
* If we want to play safe and all that, just use a AVLRU32TREE (or AVLRU64TREE
* if lazy) AVL tree from IPRT. Since we know exactly how it's implemented and
* works, there will be no uncertanties like this when using it (both here
* and in the i_insert validation logic). */
LogRelFunc(("Caught bad_alloc! We're truely buggered now!\n"));
}
}
}
else
RetAddr.u = 0;
return RetAddr;
}
/**
* Allocate the given address.
*
* @returns Success indicator.
* @param a_Addr The IP address to allocate (network order).
*/
bool IPv4Pool::allocate(RTNETADDRIPV4 a_Addr)
{
/*
* Find the range containing a_Addr.
*/
it_t it = m_pool.lower_bound(IPv4Range(a_Addr)); /* candidate range */
if (it != m_pool.end())
{
Assert(RT_N2H_U32(a_Addr.u) <= it->LastAddr); /* by definition of < and lower_bound */
if (it->contains(a_Addr))
{
/*
* Remove a_Addr from the range by way of re-insertion.
*/
const IPV4HADDR haddr = RT_N2H_U32(a_Addr.u);
IPV4HADDR first = it->FirstAddr;
IPV4HADDR last = it->LastAddr;
m_pool.erase(it);
if (first != last)
{
if (haddr == first)
i_insert(++first, last);
else if (haddr == last)
i_insert(first, --last);
else
{
i_insert(first, haddr - 1);
i_insert(haddr + 1, last);
}
}
return true;
}
}
return false;
}
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