VILLASnode/include/villas/kernel/if.hpp

/* Interface related functions.
 *
 * These functions are used to manage a network interface.
 * Most of them make use of Linux-specific APIs.
 *
 * Author: Steffen Vogel <post@steffenvogel.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#pragma once

#include <list>

#include <sys/socket.h>
#include <sys/types.h>

#include <villas/log.hpp>

#ifndef SO_MARK
#define SO_MARK                                                                \
  36 // Workaround: add missing constant for OPAL-RT Redhawk target
#endif

// Forward declarations
struct nl_addr;
struct rtnl_link;
struct rtnl_qdisc;

namespace villas {
namespace node {

// Forward declarations
class Node;
class SuperNode;

} // namespace node

namespace kernel {

// Interface data structure
class Interface {

public:
  struct rtnl_link *nl_link; // libnl3: Handle of interface.
  struct rtnl_qdisc
      *tc_qdisc; // libnl3: Root priority queuing discipline (qdisc).

protected:
  int affinity; // IRQ / Core Affinity of this interface.

  std::list<int> irqs;           // List of IRQs of the NIC.
  std::list<node::Node *> nodes; // List of nodes which use this interface.

  Logger logger;

public:
  // Add a new interface to the global list and lookup name, irqs...
  Interface(struct rtnl_link *link, int affinity = 0);
  ~Interface();

  /* Start interface.
   *
   * This setups traffic controls queue discs, network emulation and
   * maps interface IRQs according to affinity.
   *
   * @param i A pointer to the interface structure.
   * @retval 0 Success. Everything went well.
   * @retval <0 Error. Something went wrong.
   */
  int start();

  /* Stop interface
   *
   * This resets traffic qdiscs ant network emulation
   * and maps interface IRQs to all CPUs.
   *
   * @param i A pointer to the interface structure.
   * @retval 0 Success. Everything went well.
   * @retval <0 Error. Something went wrong.
   */
  int stop();

  /* Find existing or create new interface instance on which packets for a certain destination
   *  will leave the system.
   */
  static Interface *getEgress(struct sockaddr *sa, node::SuperNode *sn);

  /* Get all IRQs for this interface.
   *
   * Only MSI IRQs are determined by looking at:
   *  /sys/class/net/{ifname}/device/msi_irqs/
   *
   * @param i A pointer to the interface structure
   * @retval 0 Success. Everything went well.
   * @retval <0 Error. Something went wrong.
   */
  int getIRQs();

  /* Change the SMP affinity of NIC interrupts.
   *
   * @param i A pointer to the interface structure
   * @param affinity A mask specifying which cores should handle this interrupt.
   * @retval 0 Success. Everything went well.
   * @retval <0 Error. Something went wrong.
   */
  int setAffinity(int affinity);

  std::string getName() const;

  void addNode(node::Node *n) { nodes.push_back(n); }
};

} // namespace kernel
} // namespace villas