218 lines
5.5 KiB
C++
218 lines
5.5 KiB
C++
/*
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* \brief Simple loop-back pseudo network adaptor
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* \author Norman Feske
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* \date 2009-11-13
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*
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* This program showcases the server-side use of the 'Nic_session' interface.
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*/
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/*
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* Copyright (C) 2009-2013 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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#include <base/env.h>
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#include <base/sleep.h>
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#include <os/server.h>
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#include <root/component.h>
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#include <util/arg_string.h>
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#include <util/misc_math.h>
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#include <nic/component.h>
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#include <nic/packet_allocator.h>
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namespace Nic {
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class Loopback_component;
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class Root;
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}
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namespace Server { struct Main; }
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class Nic::Loopback_component : public Nic::Session_component
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{
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public:
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/**
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* Constructor
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*
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* \param tx_buf_size buffer size for tx channel
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* \param rx_buf_size buffer size for rx channel
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* \param rx_block_md_alloc backing store of the meta data of the
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* rx block allocator
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* \param ram_session RAM session to allocate tx and rx buffers
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* \param ep entry point used for packet stream
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* channels
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*/
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Loopback_component(Genode::size_t const tx_buf_size,
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Genode::size_t const rx_buf_size,
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Genode::Allocator &rx_block_md_alloc,
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Genode::Ram_session &ram_session,
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Server::Entrypoint &ep)
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: Session_component(tx_buf_size, rx_buf_size,
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rx_block_md_alloc, ram_session, ep)
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{ }
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Mac_address mac_address() override
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{
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Mac_address result = {{1,2,3,4,5,6}};
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return result;
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}
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bool link_state() override
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{
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/* XXX always return true, for now */
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return true;
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}
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void _handle_packet_stream() override;
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};
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void Nic::Loopback_component::_handle_packet_stream()
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{
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using namespace Genode;
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unsigned const alloc_size = Nic::Packet_allocator::DEFAULT_PACKET_SIZE;
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/* loop unless we cannot make any progress */
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for (;;) {
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/* flush acknowledgements for the echoes packets */
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while (_rx.source()->ack_avail())
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_rx.source()->release_packet(_rx.source()->get_acked_packet());
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/*
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* If the client cannot accept new acknowledgements for a sent packets,
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* we won't consume the sent packet.
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*/
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if (!_tx.sink()->ready_to_ack())
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return;
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/*
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* Nothing to be done if the client has not sent any packets.
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*/
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if (!_tx.sink()->packet_avail())
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return;
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/*
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* Here we know that the client has submitted a packet to us and is also
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* able it receive the corresponding acknowledgement.
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*/
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/*
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* The client fails to pick up the packets from the rx channel. So we
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* won't try to submit new packets.
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*/
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if (!_rx.source()->ready_to_submit())
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return;
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/*
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* We are safe to process one packet without blocking.
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*/
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Packet_descriptor packet_to_client;
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try {
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packet_to_client = _rx.source()->alloc_packet(alloc_size);
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} catch (Session::Rx::Source::Packet_alloc_failed) {
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continue;
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}
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/* obtain packet */
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Packet_descriptor const packet_from_client = _tx.sink()->get_packet();
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if (!packet_from_client.valid()) {
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PWRN("received invalid packet");
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_rx.source()->release_packet(packet_to_client);
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continue;
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}
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Genode::memcpy(_rx.source()->packet_content(packet_to_client),
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_tx.sink()->packet_content(packet_from_client),
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packet_from_client.size());
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packet_to_client = Packet_descriptor(packet_to_client.offset(),
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packet_from_client.size());
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_rx.source()->submit_packet(packet_to_client);
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_tx.sink()->acknowledge_packet(packet_from_client);
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}
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}
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class Nic::Root : public Genode::Root_component<Loopback_component>
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{
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private:
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Server::Entrypoint &_ep;
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protected:
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Loopback_component*_create_session(const char *args)
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{
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using namespace Genode;
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size_t ram_quota = Arg_string::find_arg(args, "ram_quota" ).ulong_value(0);
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size_t tx_buf_size = Arg_string::find_arg(args, "tx_buf_size").ulong_value(0);
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size_t rx_buf_size = Arg_string::find_arg(args, "rx_buf_size").ulong_value(0);
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/* deplete ram quota by the memory needed for the session structure */
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size_t session_size = max(4096UL, (unsigned long)sizeof(Session_component));
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if (ram_quota < session_size)
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throw Root::Quota_exceeded();
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/*
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* Check if donated ram quota suffices for both communication
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* buffers and check for overflow
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*/
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if (tx_buf_size + rx_buf_size < tx_buf_size ||
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tx_buf_size + rx_buf_size > ram_quota - session_size) {
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PERR("insufficient 'ram_quota', got %zd, need %zd",
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ram_quota, tx_buf_size + rx_buf_size + session_size);
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throw Root::Quota_exceeded();
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}
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return new (md_alloc()) Loopback_component(tx_buf_size, rx_buf_size,
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*env()->heap(),
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*env()->ram_session(),
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_ep);
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}
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public:
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Root(Server::Entrypoint &ep, Genode::Allocator &md_alloc)
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:
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Genode::Root_component<Loopback_component>(&ep.rpc_ep(), &md_alloc),
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_ep(ep)
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{ }
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};
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struct Server::Main
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{
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Entrypoint &ep;
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Nic::Root nic_root { ep, *Genode::env()->heap() };
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Main(Entrypoint &ep) : ep(ep)
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{
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Genode::env()->parent()->announce(ep.manage(nic_root));
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}
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};
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namespace Server {
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char const *name() { return "nicloop_ep"; }
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size_t stack_size() { return 2*1024*sizeof(long); }
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void construct(Entrypoint &ep)
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{
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static Main main(ep);
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}
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}
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