Re-work of thread model

src/lwipDriver.hpp

@@ -0,0 +1,179 @@
+/*
+ * ZeroTier SDK - Network Virtualization Everywhere
+ * Copyright (C) 2011-2019  ZeroTier, Inc.  https://www.zerotier.com/
+ *
+ * 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, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ * --
+ *
+ * You can be released from the requirements of the license by purchasing
+ * a commercial license. Buying such a license is mandatory as soon as you
+ * develop commercial closed-source software that incorporates or links
+ * directly against ZeroTier software without disclosing the source code
+ * of your own application.
+ */
+
+/**
+ * @file
+ *
+ * lwIP network stack driver
+ */
+
+#ifndef LIBZT_LWIP_DRIVER_HPP
+#define LIBZT_LWIP_DRIVER_HPP
+
+#include "Debug.hpp"
+#include "lwip/err.h"
+
+namespace ZeroTier {
+
+class MAC;
+class Mutex;
+class VirtualTap;
+struct InetAddress;
+
+/**
+ * @brief Structure used to associate packets with interfaces.
+ */
+struct zts_sorted_packet
+{
+	// lwIP pbuf containing packet (originally encapsulated by ZT packet)
+	struct pbuf *p;
+	// ZT VirtualTap from which this packet originates
+	VirtualTap *vtap;
+	// lwIP netif we should accept this packet on
+	struct netif *n;
+};
+
+/**
+ * @brief Return whether a given netif's NETIF_FLAG_UP flag is set
+ *
+ * @usage This is a convenience function to encapsulate a macro
+ */
+bool lwip_is_netif_up(void *netif);
+
+/**
+ * @brief Increase the delay multiplier for the main driver loop
+ *
+ * @usage This should be called when we know the stack won't be used by any virtual taps
+ */
+void lwip_hibernate_driver();
+
+/**
+ * @brief Decrease the delay multiplier for the main driver loop
+ *
+ * @usage This should be called when at least one virtual tap is active
+ */
+void lwip_wake_driver();
+
+/**
+ * @brief Initialize network stack semaphores, threads, and timers.
+ *
+ * @usage This is called during the initial setup of each VirtualTap but is only allowed to execute once
+ * @return
+ */
+void lwip_driver_init();
+
+/**
+ * @brief Shutdown the stack as completely as possible (not officially supported by lwIP)
+ *
+ * @usage This is to be called after it is determined that no further network activity will take place.
+ * The tcpip thread will be stopped, all interfaces will be brought down and all resources will 
+ * be deallocated. A full application restart will be required to bring the stack back online.
+ * @return
+ */
+void lwip_driver_shutdown();
+
+/**
+ * @brief Bring down and delete all interfaces belonging to the given virtual tap
+ *
+ * @usage This is to be called when the application desires to stop all traffic processing in the 
+ * stack. Unlike lwip_driver_shutdown(), the application can easily resume traffic processing 
+ * by re-adding a virtual tap (and associated lwip netifs)
+ * @return
+ */
+void lwip_dispose_of_netifs(void *tapref);
+
+/**
+ * @brief Initialize and start the DNS client
+ *
+ * @usage Called after lwip_driver_init()
+ * @return
+ */
+void lwip_dns_init();
+
+/**
+ * @brief Starts DHCP timers
+ *
+ * @usage lwip_driver_init()
+ * @return
+ */
+void lwip_start_dhcp(void *netif);
+
+/**
+ * @brief Called when the status of a netif changes:
+ *  - Interface is up/down (ZTS_EVENT_NETIF_UP, ZTS_EVENT_NETIF_DOWN)
+ *  - Address changes while up (ZTS_EVENT_NETIF_NEW_ADDRESS)
+ */
+static void netif_status_callback(struct netif *netif);
+
+/**
+ * @brief Called when a netif is removed (ZTS_EVENT_NETIF_INTERFACE_REMOVED)
+ */
+static void netif_remove_callback(struct netif *netif);
+
+/**
+ * @brief Called when a link is brought up or down (ZTS_EVENT_NETIF_LINK_UP, ZTS_EVENT_NETIF_LINK_DOWN)
+ */
+static void netif_link_callback(struct netif *netif);
+
+/**
+ * @brief Set up an interface in the network stack for the VirtualTap.
+ *
+ * @param
+ * @param tapref Reference to VirtualTap that will be responsible for sending and receiving data
+ * @param mac Virtual hardware address for this ZeroTier VirtualTap interface
+ * @param ip Virtual IP address for this ZeroTier VirtualTap interface
+ * @return
+ */
+void lwip_init_interface(void *tapref, const MAC &mac, const InetAddress &ip);
+
+/**
+ * @brief Called from the stack, outbound ethernet frames from the network stack enter the ZeroTier virtual wire here.
+ *
+ * @usage This shall only be called from the stack or the stack driver. Not the application thread.
+ * @param netif Transmits an outgoing Ethernet fram from the network stack onto the ZeroTier virtual wire
+ * @param p A pointer to the beginning of a chain pf struct pbufs
+ * @return
+ */
+err_t lwip_eth_tx(struct netif *netif, struct pbuf *p);
+
+/**
+ * @brief Receives incoming Ethernet frames from the ZeroTier virtual wire
+ *
+ * @usage This shall be called from the VirtualTap's I/O thread (via VirtualTap::put())
+ * @param tap Pointer to VirtualTap from which this data comes
+ * @param from Origin address (virtual ZeroTier hardware address)
+ * @param to Intended destination address (virtual ZeroTier hardware address)
+ * @param etherType Protocol type
+ * @param data Pointer to Ethernet frame
+ * @param len Length of Ethernet frame
+ * @return
+ */
+void lwip_eth_rx(VirtualTap *tap, const MAC &from, const MAC &to, unsigned int etherType,
+	const void *data, unsigned int len);
+
+} // namespace ZeroTier
+
+#endif // _H