3c25d989f3
The nic_router component can be used to individually route IPv4 packets between multiple NIC sessions. Thereby, it can translate between different IP subnets. The component supports port forwarding, as well as the partitioning of the TCP and UDP port spaces. Fixes #114
81 lines
1.5 KiB
C++
81 lines
1.5 KiB
C++
/*
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* \brief MAC-address allocator
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* \author Stefan Kalkowski
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* \date 2010-08-25
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*/
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/*
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* Copyright (C) 2010-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _MAC_H_
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#define _MAC_H_
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/* Genode */
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#include <base/exception.h>
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#include <net/ethernet.h>
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namespace Net {
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/**
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* The MAC allocator is used to administer MAC addresses for
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* the proxy-ARP's client's.
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*/
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class Mac_allocator
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{
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private:
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/* limit available MAC addresses to one byte range */
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enum { MSB_MAX = 0xFF };
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/* signals, whether most significant byte is in use */
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typedef struct
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{
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unsigned used : 1;
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} Msb;
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Msb _msbs[MSB_MAX]; /* bitfield of MSBs */
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public:
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struct Alloc_failed : Genode::Exception {};
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/* reference MAC address */
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static Mac_address mac_addr_base;
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Mac_allocator() { Genode::memset(&_msbs, 0, sizeof(_msbs)); }
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/**
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* Allocates a new MAC address.
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*
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* \throws Alloc_failed if no more MAC addresses are available.
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* \return MAC address
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*/
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Mac_address alloc()
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{
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for (int i=0; i < MSB_MAX; i++) {
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if (!_msbs[i].used) {
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_msbs[i].used = 1;
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Mac_address mac = mac_addr_base;
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mac.addr[5] = i;
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return mac;
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}
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}
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throw Alloc_failed();
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}
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/**
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* Frees a formerly allocated MAC address.
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*/
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void free(Mac_address mac) {
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_msbs[(unsigned)mac.addr[5]].used = 0; }
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};
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}
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#endif /* _MAC_H_ */
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