VILLASnode/lib/kernel/tc.cpp

/** Traffic control (tc): setup interface queuing desciplines.
 *
 * VILLASnode uses these functions to setup the network emulation feature.
 *
 * @author Steffen Vogel <post@steffenvogel.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license Apache 2.0
 *********************************************************************************/

#include <netlink/route/cls/fw.h>
#include <netlink/route/qdisc/prio.h>

#include <linux/if_ether.h>

#include <villas/utils.hpp>
#include <villas/exceptions.hpp>
#include <villas/kernel/kernel.hpp>
#include <villas/kernel/if.hpp>
#include <villas/kernel/tc.hpp>
#include <villas/kernel/nl.hpp>

using namespace villas;
using namespace villas::kernel;

int villas::kernel::tc::prio(Interface *i, struct rtnl_qdisc **qd, tc_hdl_t handle, tc_hdl_t parent, int bands)
{
	int ret;
	struct nl_sock *sock = nl::init();
	struct rtnl_qdisc *q = rtnl_qdisc_alloc();

	ret = kernel::loadModule("sch_prio");
	if (ret)
		throw RuntimeError("Failed to load kernel module: sch_prio ({})", ret);

	/* This is the default priomap used by the tc-prio qdisc
	 * We will use the first 'bands' bands internally */
	uint8_t map[] = QDISC_PRIO_DEFAULT_PRIOMAP;
	for (unsigned i = 0; i < ARRAY_LEN(map); i++)
		map[i] += bands;

	rtnl_tc_set_link(TC_CAST(q), i->nl_link);
	rtnl_tc_set_parent(TC_CAST(q), parent);
	rtnl_tc_set_handle(TC_CAST(q), handle);
	rtnl_tc_set_kind(TC_CAST(q), "prio");

	rtnl_qdisc_prio_set_bands(q, bands + 3);
	rtnl_qdisc_prio_set_priomap(q, map, sizeof(map));

	ret = rtnl_qdisc_add(sock, q, NLM_F_CREATE | NLM_F_REPLACE);

	*qd = q;

	auto logger = logging.get("kernel");
	logger->debug("Added prio qdisc with {} bands to interface '{}'", bands, rtnl_link_get_name(i->nl_link));

	return ret;
}

int villas::kernel::tc::mark(Interface *i, struct rtnl_cls **cls, tc_hdl_t flowid, uint32_t mark)
{
	int ret;
	struct nl_sock *sock = nl::init();
	struct rtnl_cls *c = rtnl_cls_alloc();

	ret = kernel::loadModule("cls_fw");
	if (ret)
		throw RuntimeError("Failed to load kernel module: cls_fw");

	rtnl_tc_set_link(TC_CAST(c), i->nl_link);
	rtnl_tc_set_handle(TC_CAST(c), mark);
	rtnl_tc_set_kind(TC_CAST(c), "fw");

	rtnl_cls_set_protocol(c, ETH_P_ALL);

	rtnl_fw_set_classid(c, flowid);
	rtnl_fw_set_mask(c, 0xFFFFFFFF);

	ret = rtnl_cls_add(sock, c, NLM_F_CREATE);

	*cls = c;

	auto logger = logging.get("kernel");
	logger->debug("Added fwmark classifier with mark {} to interface '{}'", mark, rtnl_link_get_name(i->nl_link));

	return ret;
}

int villas::kernel::tc::reset(Interface *i)
{
	struct nl_sock *sock = nl::init();

	/* We restore the default pfifo_fast qdisc, by deleting ours */
	return rtnl_qdisc_delete(sock, i->tc_qdisc);
}