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// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2015 Red Hat, Inc.
 */

#include "nm-default.h"

#include "nm-platform-utils.h"

#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>
#include <linux/mii.h>
#include <linux/if.h>
#include <linux/version.h>
#include <linux/rtnetlink.h>
#include <fcntl.h>
#include <libudev.h>

#include "nm-utils.h"
#include "nm-setting-wired.h"
#include "nm-libnm-core-intern/nm-ethtool-utils.h"

#include "nm-core-utils.h"

#define ONOFF(bool_val) ((bool_val) ? "on" : "off")

/******************************************************************************
 * utils
 *****************************************************************************/

extern char *if_indextoname (unsigned __ifindex, char *__ifname);
unsigned if_nametoindex (const char *__ifname);

const char *
nmp_utils_if_indextoname (int ifindex, char *out_ifname/*IFNAMSIZ*/)
{
	g_return_val_if_fail (ifindex > 0, NULL);
	g_return_val_if_fail (out_ifname, NULL);

	return if_indextoname (ifindex, out_ifname);
}

int
nmp_utils_if_nametoindex (const char *ifname)
{
	g_return_val_if_fail (ifname, 0);

	return if_nametoindex (ifname);
}

/*****************************************************************************/

typedef struct {
	int fd;
	const int ifindex;
	char ifname[IFNAMSIZ];
} SocketHandle;

#define SOCKET_HANDLE_INIT(_ifindex) \
	{ \
		.fd = -1, \
		.ifindex = (_ifindex), \
	}

static void
_nm_auto_socket_handle (SocketHandle *shandle)
{
	if (shandle->fd >= 0)
		nm_close (shandle->fd);
}

#define nm_auto_socket_handle nm_auto(_nm_auto_socket_handle)

/*****************************************************************************/

typedef enum {
	IOCTL_CALL_DATA_TYPE_NONE,
	IOCTL_CALL_DATA_TYPE_IFRDATA,
	IOCTL_CALL_DATA_TYPE_IFRU,
} IoctlCallDataType;

static int
_ioctl_call (const char *log_ioctl_type,
             const char *log_subtype,
             unsigned long int ioctl_request,
             int ifindex,
             int *inout_fd,
             char *inout_ifname,
             IoctlCallDataType edata_type,
             gpointer edata,
             gsize edata_size,
             struct ifreq *out_ifreq)
{
	nm_auto_close int fd_close = -1;
	int fd;
	int r;
	gpointer edata_backup = NULL;
	gs_free gpointer edata_backup_free = NULL;
	guint try_count;
	char known_ifnames[2][IFNAMSIZ];
	const char *failure_reason = NULL;
	struct ifreq ifr;

	nm_assert (ifindex > 0);
	nm_assert (NM_IN_SET (edata_type, IOCTL_CALL_DATA_TYPE_NONE,
	                                  IOCTL_CALL_DATA_TYPE_IFRDATA,
	                                  IOCTL_CALL_DATA_TYPE_IFRU));
	nm_assert (edata_type != IOCTL_CALL_DATA_TYPE_NONE    || edata_size == 0);
	nm_assert (edata_type != IOCTL_CALL_DATA_TYPE_IFRDATA || edata_size > 0);
	nm_assert (edata_type != IOCTL_CALL_DATA_TYPE_IFRU    || (edata_size > 0 && edata_size <= sizeof (ifr.ifr_ifru)));
	nm_assert (edata_size == 0 || edata);

	/* open a file descriptor (or use the one provided). */
	if (   inout_fd
	    && *inout_fd >= 0)
		fd = *inout_fd;
	else {
		fd = socket (PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
		if (fd < 0) {
			r = -NM_ERRNO_NATIVE (errno);
			failure_reason = "failed creating socket or ioctl";
			goto out;
		}
		if (inout_fd)
			*inout_fd = fd;
		else
			fd_close = fd;
	}

	/* resolve the ifindex to name (or use the one provided). */
	if (   inout_ifname
	    && inout_ifname[0])
		nm_utils_ifname_cpy (known_ifnames[0], inout_ifname);
	else {
		if (!nmp_utils_if_indextoname (ifindex, known_ifnames[0])) {
			failure_reason = "cannot resolve ifindex";
			r = -ENODEV;
			goto out;
		}
		if (inout_ifname)
			nm_utils_ifname_cpy (inout_ifname, known_ifnames[0]);
	}

	/* we might need to retry the request. Backup edata so that we can
	 * restore it on retry. */
	if (edata_size > 0)
		edata_backup = nm_memdup_maybe_a (500, edata, edata_size, &edata_backup_free);

	try_count = 0;

again:
	{
		const char *ifname = known_ifnames[try_count % 2];

		nm_assert (ifindex > 0);
		nm_assert (ifname && nm_utils_ifname_valid_kernel (ifname, NULL));
		nm_assert (fd >= 0);

		memset (&ifr, 0, sizeof (ifr));
		nm_utils_ifname_cpy (ifr.ifr_name, ifname);
		if (edata_type == IOCTL_CALL_DATA_TYPE_IFRDATA)
			ifr.ifr_data = edata;
		else if (edata_type == IOCTL_CALL_DATA_TYPE_IFRU)
			memcpy (&ifr.ifr_ifru, edata, NM_MIN (edata_size, sizeof (ifr.ifr_ifru)));

		if (ioctl (fd, ioctl_request, &ifr) < 0) {
			r = -NM_ERRNO_NATIVE (errno);
			nm_log_trace (LOGD_PLATFORM, "%s[%d]: %s, %s: failed: %s",
			              log_ioctl_type,
			              ifindex,
			              log_subtype,
			              ifname,
			              nm_strerror_native (-r));
		} else {
			r = 0;
			nm_log_trace (LOGD_PLATFORM, "%s[%d]: %s, %s: success",
			              log_ioctl_type,
			              ifindex,
			              log_subtype,
			              ifname);
		}
	}

	try_count++;

	/* resolve the name again to see whether the ifindex still has the same name. */
	if (!nmp_utils_if_indextoname (ifindex, known_ifnames[try_count % 2])) {
		/* we could not find the ifindex again. Probably the device just got
		 * removed.
		 *
		 * In both cases we return the error code we got from ioctl above.
		 * Either it failed because the device was gone already or it still
		 * managed to complete the call. In both cases, the error code is good. */
		failure_reason = "cannot resolve ifindex after ioctl call. Probably the device was just removed";
		goto out;
	}

	/* check whether the ifname changed in the meantime. If yes, would render the result
	 * invalid. Note that this cannot detect every race regarding renames, for example:
	 *
	 *  - if_indextoname(#10) gives eth0
	 *  - rename(#10) => eth0_tmp
	 *  - rename(#11) => eth0
	 *  - ioctl(eth0) (wrongly fetching #11, formerly eth1)
	 *  - rename(#11) => eth_something
	 *  - rename(#10) => eth0
	 *  - if_indextoname(#10) gives eth0
	 */
	if (!nm_streq (known_ifnames[0], known_ifnames[1])) {
		gboolean retry;

		/* we detected a possible(!) rename.
		 *
		 * For getters it's straight forward to just retry the call.
		 *
		 * For setters we also always retry. If our previous call operated on the right device,
		 * calling it again should have no bad effect (just setting the same thing more than once).
		 *
		 * The only potential bad thing is if there was a race involving swapping names, and we just
		 * set the ioctl option on the wrong device. But then the bad thing already happend and
		 * we cannot detect it (nor do anything about it). At least, we can retry and set the
		 * option on the right interface. */
		retry = (try_count < 5);

		nm_log_trace (LOGD_PLATFORM, "%s[%d]: %s: rename detected from \"%s\" to \"%s\". %s",
		              log_ioctl_type,
		              ifindex,
		              log_subtype,
		              known_ifnames[(try_count - 1) % 2],
		              known_ifnames[ try_count      % 2],
		                retry
		              ? "Retry"
		              : "No retry");
		if (inout_ifname)
			nm_utils_ifname_cpy (inout_ifname, known_ifnames[try_count % 2]);
		if (retry) {
			if (edata_size > 0)
				memcpy (edata, edata_backup, edata_size);
			goto again;
		}
	}

out:
	if (failure_reason) {
		nm_log_trace (LOGD_PLATFORM, "%s[%d]: %s: %s: %s",
		              log_ioctl_type,
		              ifindex,
		              log_subtype,
		              failure_reason,
		                r < 0
		              ? nm_strerror_native (-r)
		              : "assume success");
	}
	if (r >= 0)
		NM_SET_OUT (out_ifreq, ifr);
	return r;
}

/******************************************************************************
 * ethtool
 *****************************************************************************/

static
NM_UTILS_ENUM2STR_DEFINE (_ethtool_cmd_to_string, guint32,
	NM_UTILS_ENUM2STR (ETHTOOL_GCOALESCE,  "ETHTOOL_GCOALESCE"),
	NM_UTILS_ENUM2STR (ETHTOOL_GDRVINFO,   "ETHTOOL_GDRVINFO"),
	NM_UTILS_ENUM2STR (ETHTOOL_GFEATURES,  "ETHTOOL_GFEATURES"),
	NM_UTILS_ENUM2STR (ETHTOOL_GLINK,      "ETHTOOL_GLINK"),
	NM_UTILS_ENUM2STR (ETHTOOL_GPERMADDR,  "ETHTOOL_GPERMADDR"),
	NM_UTILS_ENUM2STR (ETHTOOL_GRINGPARAM, "ETHTOOL_GRINGPARAM"),
	NM_UTILS_ENUM2STR (ETHTOOL_GSET,       "ETHTOOL_GSET"),
	NM_UTILS_ENUM2STR (ETHTOOL_GSSET_INFO, "ETHTOOL_GSSET_INFO"),
	NM_UTILS_ENUM2STR (ETHTOOL_GSTATS,     "ETHTOOL_GSTATS"),
	NM_UTILS_ENUM2STR (ETHTOOL_GSTRINGS,   "ETHTOOL_GSTRINGS"),
	NM_UTILS_ENUM2STR (ETHTOOL_GWOL,       "ETHTOOL_GWOL"),
	NM_UTILS_ENUM2STR (ETHTOOL_SCOALESCE,  "ETHTOOL_SCOALESCE"),
	NM_UTILS_ENUM2STR (ETHTOOL_SFEATURES,  "ETHTOOL_SFEATURES"),
	NM_UTILS_ENUM2STR (ETHTOOL_SRINGPARAM, "ETHTOOL_SRINGPARAM"),
	NM_UTILS_ENUM2STR (ETHTOOL_SSET,       "ETHTOOL_SSET"),
	NM_UTILS_ENUM2STR (ETHTOOL_SWOL,       "ETHTOOL_SWOL"),
);

static const char *
_ethtool_edata_to_string (gpointer edata, gsize edata_size, char *sbuf, gsize sbuf_len)
{
	nm_assert (edata);
	nm_assert (edata_size >= sizeof (guint32));
	nm_assert ((((intptr_t) edata) % _nm_alignof (guint32)) == 0);

	return _ethtool_cmd_to_string (*((guint32 *) edata), sbuf, sbuf_len);
}

/*****************************************************************************/

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
#define ethtool_cmd_speed(pedata) ((pedata)->speed)

#define ethtool_cmd_speed_set(pedata, speed) \
	G_STMT_START { (pedata)->speed = (guint16) (speed); } G_STMT_END
#endif

static int
_ethtool_call_handle (SocketHandle *shandle, gpointer edata, gsize edata_size)
{
	char sbuf[50];

	return _ioctl_call ("ethtool",
	                    _ethtool_edata_to_string (edata, edata_size, sbuf, sizeof (sbuf)),
	                    SIOCETHTOOL,
	                    shandle->ifindex,
	                    &shandle->fd,
	                    shandle->ifname,
	                    IOCTL_CALL_DATA_TYPE_IFRDATA,
	                    edata,
	                    edata_size,
	                    NULL);
}

static int
_ethtool_call_once (int ifindex, gpointer edata, gsize edata_size)
{
	char sbuf[50];

	return _ioctl_call ("ethtool",
	                    _ethtool_edata_to_string (edata, edata_size, sbuf, sizeof (sbuf)),
	                    SIOCETHTOOL,
	                    ifindex,
	                    NULL,
	                    NULL,
	                    IOCTL_CALL_DATA_TYPE_IFRDATA,
	                    edata,
	                    edata_size,
	                    NULL);
}

/*****************************************************************************/

static struct ethtool_gstrings *
ethtool_get_stringset (SocketHandle *shandle, int stringset_id)
{
	struct {
		struct ethtool_sset_info info;
		guint32 sentinel;
	} sset_info = {
		.info.cmd = ETHTOOL_GSSET_INFO,
		.info.reserved = 0,
		.info.sset_mask = (1ULL << stringset_id),
	};
	const guint32 *pdata;
	gs_free struct ethtool_gstrings *gstrings = NULL;
	gsize gstrings_len;
	guint32 i, len;

	if (_ethtool_call_handle (shandle, &sset_info, sizeof (sset_info)) < 0)
		return NULL;
	if (!sset_info.info.sset_mask)
		return NULL;

	pdata = (guint32 *) sset_info.info.data;

	len = *pdata;

	gstrings_len = sizeof (*gstrings) + (len * ETH_GSTRING_LEN);
	gstrings = g_malloc0 (gstrings_len);
	gstrings->cmd = ETHTOOL_GSTRINGS;
	gstrings->string_set = stringset_id;
	gstrings->len = len;
	if (gstrings->len > 0) {
		if (_ethtool_call_handle (shandle, gstrings, gstrings_len) < 0)
			return NULL;
		for (i = 0; i < gstrings->len; i++) {
			/* ensure NUL terminated */
			gstrings->data[i * ETH_GSTRING_LEN + (ETH_GSTRING_LEN - 1)] = '\0';
		}
	}

	return g_steal_pointer (&gstrings);
}

static int
ethtool_gstrings_find (const struct ethtool_gstrings *gstrings, const char *needle)
{
	guint32 i;

	/* ethtool_get_stringset() always ensures NUL terminated strings at ETH_GSTRING_LEN.
	 * that means, we cannot possibly request longer names. */
	nm_assert (needle && strlen (needle) < ETH_GSTRING_LEN);

	for (i = 0; i < gstrings->len; i++) {
		if (nm_streq ((char *) &gstrings->data[i * ETH_GSTRING_LEN], needle))
			return i;
	}
	return -1;
}

static int
ethtool_get_stringset_index (SocketHandle *shandle, int stringset_id, const char *needle)
{
	gs_free struct ethtool_gstrings *gstrings = NULL;

	/* ethtool_get_stringset() always ensures NUL terminated strings at ETH_GSTRING_LEN.
	 * that means, we cannot possibly request longer names. */
	nm_assert (needle && strlen (needle) < ETH_GSTRING_LEN);

	gstrings = ethtool_get_stringset (shandle, stringset_id);
	if (gstrings)
		return ethtool_gstrings_find (gstrings, needle);
	return -1;
}

/*****************************************************************************/

static const NMEthtoolFeatureInfo _ethtool_feature_infos[_NM_ETHTOOL_ID_FEATURE_NUM] = {
#define ETHT_FEAT(eid, ...) \
	{ \
		.ethtool_id = eid, \
		.n_kernel_names = NM_NARG (__VA_ARGS__), \
		.kernel_names = ((const char *const[]) { __VA_ARGS__ }), \
	}

	/* the order does only matter for one thing: if it happens that more than one NMEthtoolID
	 * reference the same kernel-name, then the one that is mentioned *later* will win in
	 * case these NMEthtoolIDs are set. That mostly only makes sense for ethtool-ids which
	 * refer to multiple features ("feature-tso"), while also having more specific ids
	 * ("feature-tx-tcp-segmentation"). */

	/* names from ethtool utility, which are aliases for multiple features. */
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_SG,                           "tx-scatter-gather",
	                                                               "tx-scatter-gather-fraglist"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TSO,                          "tx-tcp-segmentation",
	                                                               "tx-tcp-ecn-segmentation",
	                                                               "tx-tcp-mangleid-segmentation",
	                                                               "tx-tcp6-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX,                           "tx-checksum-ipv4",
	                                                               "tx-checksum-ip-generic",
	                                                               "tx-checksum-ipv6",
	                                                               "tx-checksum-fcoe-crc",
	                                                               "tx-checksum-sctp"),

	/* names from ethtool utility, which are aliases for one feature. */
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_GRO,                          "rx-gro"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_GSO,                          "tx-generic-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_LRO,                          "rx-lro"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_NTUPLE,                       "rx-ntuple-filter"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX,                           "rx-checksum"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RXHASH,                       "rx-hashing"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RXVLAN,                       "rx-vlan-hw-parse"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TXVLAN,                       "tx-vlan-hw-insert"),

	/* names of features, as known by kernel. */
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_ESP_HW_OFFLOAD,               "esp-hw-offload"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_ESP_TX_CSUM_HW_OFFLOAD,       "esp-tx-csum-hw-offload"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_FCOE_MTU,                     "fcoe-mtu"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_HIGHDMA,                      "highdma"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_HW_TC_OFFLOAD,                "hw-tc-offload"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_L2_FWD_OFFLOAD,               "l2-fwd-offload"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_LOOPBACK,                     "loopback"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_ALL,                       "rx-all"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_FCS,                       "rx-fcs"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_GRO_HW,                    "rx-gro-hw"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_UDP_TUNNEL_PORT_OFFLOAD,   "rx-udp_tunnel-port-offload"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_VLAN_FILTER,               "rx-vlan-filter"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_VLAN_STAG_FILTER,          "rx-vlan-stag-filter"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_RX_VLAN_STAG_HW_PARSE,        "rx-vlan-stag-hw-parse"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TLS_HW_RECORD,                "tls-hw-record"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TLS_HW_TX_OFFLOAD,            "tls-hw-tx-offload"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_CHECKSUM_FCOE_CRC,         "tx-checksum-fcoe-crc"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_CHECKSUM_IPV4,             "tx-checksum-ipv4"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_CHECKSUM_IPV6,             "tx-checksum-ipv6"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_CHECKSUM_IP_GENERIC,       "tx-checksum-ip-generic"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_CHECKSUM_SCTP,             "tx-checksum-sctp"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_ESP_SEGMENTATION,          "tx-esp-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_FCOE_SEGMENTATION,         "tx-fcoe-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_GRE_CSUM_SEGMENTATION,     "tx-gre-csum-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_GRE_SEGMENTATION,          "tx-gre-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_GSO_PARTIAL,               "tx-gso-partial"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_GSO_ROBUST,                "tx-gso-robust"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_IPXIP4_SEGMENTATION,       "tx-ipxip4-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_IPXIP6_SEGMENTATION,       "tx-ipxip6-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_NOCACHE_COPY,              "tx-nocache-copy"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_SCATTER_GATHER,            "tx-scatter-gather"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_SCATTER_GATHER_FRAGLIST,   "tx-scatter-gather-fraglist"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_SCTP_SEGMENTATION,         "tx-sctp-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_TCP6_SEGMENTATION,         "tx-tcp6-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_TCP_ECN_SEGMENTATION,      "tx-tcp-ecn-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_TCP_MANGLEID_SEGMENTATION, "tx-tcp-mangleid-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_TCP_SEGMENTATION,          "tx-tcp-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_UDP_SEGMENTATION,          "tx-udp-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_UDP_TNL_CSUM_SEGMENTATION, "tx-udp_tnl-csum-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_UDP_TNL_SEGMENTATION,      "tx-udp_tnl-segmentation"),
	ETHT_FEAT (NM_ETHTOOL_ID_FEATURE_TX_VLAN_STAG_HW_INSERT,       "tx-vlan-stag-hw-insert"),
};

/* the number of kernel features that we handle. It essentially is the sum of all
 * kernel_names. So, all ethtool-ids that reference exactly one kernel-name
 * (_NM_ETHTOOL_ID_FEATURE_NUM) + some extra, for ethtool-ids that are aliases
 * for multiple kernel-names. */
#define N_ETHTOOL_KERNEL_FEATURES (((guint) _NM_ETHTOOL_ID_FEATURE_NUM) + 8u)

static void
_ASSERT_ethtool_feature_infos (void)
{
#if NM_MORE_ASSERTS > 10
	guint i, k, n;
	bool found[_NM_ETHTOOL_ID_FEATURE_NUM] = { };

	G_STATIC_ASSERT_EXPR (G_N_ELEMENTS (_ethtool_feature_infos) == _NM_ETHTOOL_ID_FEATURE_NUM);

	n = 0;
	for (i = 0; i < G_N_ELEMENTS (_ethtool_feature_infos); i++) {
		NMEthtoolFeatureState kstate;
		const NMEthtoolFeatureInfo *inf = &_ethtool_feature_infos[i];

		g_assert (inf->ethtool_id >= _NM_ETHTOOL_ID_FEATURE_FIRST);
		g_assert (inf->ethtool_id <= _NM_ETHTOOL_ID_FEATURE_LAST);
		g_assert (inf->n_kernel_names > 0);

		for (k = 0; k < i; k++)
			g_assert (inf->ethtool_id != _ethtool_feature_infos[k].ethtool_id);

		g_assert (!found[_NM_ETHTOOL_ID_FEATURE_AS_IDX (inf->ethtool_id)]);
		found[_NM_ETHTOOL_ID_FEATURE_AS_IDX (inf->ethtool_id)] = TRUE;

		kstate.idx_kernel_name = inf->n_kernel_names - 1;
		g_assert ((guint) kstate.idx_kernel_name == (guint) (inf->n_kernel_names - 1));

		n += inf->n_kernel_names;
		for (k = 0; k < inf->n_kernel_names; k++) {
			g_assert (nm_utils_strv_find_first ((char **) inf->kernel_names,
			                                    k,
			                                    inf->kernel_names[k]) < 0);
		}
	}

	for (i = 0; i < _NM_ETHTOOL_ID_FEATURE_NUM; i++)
		g_assert (found[i]);

	g_assert (n == N_ETHTOOL_KERNEL_FEATURES);
#endif
}

static NMEthtoolFeatureStates *
ethtool_get_features (SocketHandle *shandle)
{
	gs_free NMEthtoolFeatureStates *states = NULL;
	gs_free struct ethtool_gstrings *ss_features = NULL;

	_ASSERT_ethtool_feature_infos ();

	ss_features = ethtool_get_stringset (shandle, ETH_SS_FEATURES);
	if (!ss_features)
		return NULL;

	if (ss_features->len > 0) {
		gs_free struct ethtool_gfeatures *gfeatures_free = NULL;
		struct ethtool_gfeatures *gfeatures;
		gsize gfeatures_len;
		guint idx;
		const NMEthtoolFeatureState *states_list0 = NULL;
		const NMEthtoolFeatureState *const*states_plist0 = NULL;
		guint states_plist_n = 0;

		gfeatures_len =   sizeof (struct ethtool_gfeatures)
		                + (NM_DIV_ROUND_UP (ss_features->len, 32u) * sizeof(gfeatures->features[0]));
		gfeatures = nm_malloc0_maybe_a (300, gfeatures_len, &gfeatures_free);
		gfeatures->cmd = ETHTOOL_GFEATURES;
		gfeatures->size = NM_DIV_ROUND_UP (ss_features->len, 32u);
		if (_ethtool_call_handle (shandle, gfeatures, gfeatures_len) < 0)
			return NULL;

		for (idx = 0; idx < G_N_ELEMENTS (_ethtool_feature_infos); idx++) {
			const NMEthtoolFeatureInfo *info = &_ethtool_feature_infos[idx];
			guint idx_kernel_name;

			for (idx_kernel_name = 0; idx_kernel_name < info->n_kernel_names; idx_kernel_name++) {
				NMEthtoolFeatureState *kstate;
				const char *kernel_name = info->kernel_names[idx_kernel_name];
				int i_feature;
				guint i_block;
				guint32 i_flag;

				i_feature = ethtool_gstrings_find (ss_features, kernel_name);
				if (i_feature < 0)
					continue;

				i_block = ((guint) i_feature) / 32u;
				i_flag = (guint32) (1u << (((guint) i_feature) % 32u));

				if (!states) {
					states = g_malloc0 (sizeof (NMEthtoolFeatureStates)
					                    + (N_ETHTOOL_KERNEL_FEATURES * sizeof (NMEthtoolFeatureState))
					                    + ((N_ETHTOOL_KERNEL_FEATURES + G_N_ELEMENTS (_ethtool_feature_infos)) * sizeof (NMEthtoolFeatureState *)));
					states_list0 = &states->states_list[0];
					states_plist0 = (gpointer) &states_list0[N_ETHTOOL_KERNEL_FEATURES];
					states->n_ss_features = ss_features->len;
				}

				nm_assert (states->n_states < N_ETHTOOL_KERNEL_FEATURES);
				kstate = (NMEthtoolFeatureState *) &states_list0[states->n_states];
				states->n_states++;

				kstate->info = info;
				kstate->idx_ss_features = i_feature;
				kstate->idx_kernel_name = idx_kernel_name;
				kstate->available     = !!(gfeatures->features[i_block].available     & i_flag);
				kstate->requested     = !!(gfeatures->features[i_block].requested     & i_flag);
				kstate->active        = !!(gfeatures->features[i_block].active        & i_flag);
				kstate->never_changed = !!(gfeatures->features[i_block].never_changed & i_flag);

				nm_assert (states_plist_n < N_ETHTOOL_KERNEL_FEATURES + G_N_ELEMENTS (_ethtool_feature_infos));

				if (!states->states_indexed[_NM_ETHTOOL_ID_FEATURE_AS_IDX (info->ethtool_id)])
					states->states_indexed[_NM_ETHTOOL_ID_FEATURE_AS_IDX (info->ethtool_id)] = &states_plist0[states_plist_n];
				((const NMEthtoolFeatureState **) states_plist0)[states_plist_n] = kstate;
				states_plist_n++;
			}

			if (states && states->states_indexed[_NM_ETHTOOL_ID_FEATURE_AS_IDX (info->ethtool_id)]) {
				nm_assert (states_plist_n < N_ETHTOOL_KERNEL_FEATURES + G_N_ELEMENTS (_ethtool_feature_infos));
				nm_assert (!states_plist0[states_plist_n]);
				states_plist_n++;
			}
		}
	}

	return g_steal_pointer (&states);
}

NMEthtoolFeatureStates *
nmp_utils_ethtool_get_features (int ifindex)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);
	NMEthtoolFeatureStates *features;

	g_return_val_if_fail (ifindex > 0, 0);

	features = ethtool_get_features (&shandle);

	if (!features) {
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: failure getting features",
		              ifindex,
		              "get-features");
		return NULL;
	}

	nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: retrieved kernel features",
	              ifindex,
	              "get-features");
	return features;
}

static const char *
_ethtool_feature_state_to_string (char *buf, gsize buf_size, const NMEthtoolFeatureState *s, const char *prefix)
{
	int l;

	l = g_snprintf (buf, buf_size,
	                "%s %s%s",
	                prefix ?: "",
	                ONOFF (s->active),
	                (!s->available || s->never_changed)
	                  ? ", [fixed]"
	                  : ((s->requested != s->active)
	                       ? (s->requested ? ", [requested on]" : ", [requested off]")
	                       : ""));
	nm_assert (l < buf_size);
	return buf;
}

gboolean
nmp_utils_ethtool_set_features (int ifindex,
                                const NMEthtoolFeatureStates *features,
                                const NMTernary *requested /* indexed by NMEthtoolID - _NM_ETHTOOL_ID_FEATURE_FIRST */,
                                gboolean do_set /* or reset */)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);
	gs_free struct ethtool_sfeatures *sfeatures_free = NULL;
	struct ethtool_sfeatures *sfeatures;
	gsize sfeatures_len;
	int r;
	guint i, j;
	struct {
		const NMEthtoolFeatureState *f_state;
		NMTernary requested;
	} set_states[N_ETHTOOL_KERNEL_FEATURES];
	guint set_states_n = 0;
	gboolean success = TRUE;

	g_return_val_if_fail (ifindex > 0, 0);
	g_return_val_if_fail (features, 0);
	g_return_val_if_fail (requested, 0);

	nm_assert (features->n_states <= N_ETHTOOL_KERNEL_FEATURES);

	for (i = 0; i < _NM_ETHTOOL_ID_FEATURE_NUM; i++) {
		const NMEthtoolFeatureState *const*states_indexed;

		if (requested[i] == NM_TERNARY_DEFAULT)
			continue;

		if (!(states_indexed = features->states_indexed[i])) {
			if (do_set) {
				nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: set feature %s: skip (not found)",
				              ifindex,
				              "set-features",
				              nm_ethtool_data[i + _NM_ETHTOOL_ID_FEATURE_FIRST]->optname);
				success = FALSE;
			}
			continue;
		}

		for (j = 0; states_indexed[j]; j++) {
			const NMEthtoolFeatureState *s = states_indexed[j];
			char sbuf[255];

			if (set_states_n >= G_N_ELEMENTS (set_states))
				g_return_val_if_reached (FALSE);

			if (s->never_changed) {
				nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: %s feature %s (%s): %s, %s (skip feature marked as never changed)",
				              ifindex,
				              "set-features",
				              do_set ? "set" : "reset",
				              nm_ethtool_data[i + _NM_ETHTOOL_ID_FEATURE_FIRST]->optname,
				              s->info->kernel_names[s->idx_kernel_name],
				              ONOFF (do_set ? requested[i] == NM_TERNARY_TRUE : s->active),
				              _ethtool_feature_state_to_string (sbuf, sizeof (sbuf), s, do_set ? " currently:" : " before:"));
				continue;
			}

			nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: %s feature %s (%s): %s, %s",
			              ifindex,
			              "set-features",
			              do_set ? "set" : "reset",
			              nm_ethtool_data[i + _NM_ETHTOOL_ID_FEATURE_FIRST]->optname,
			              s->info->kernel_names[s->idx_kernel_name],
			              ONOFF (do_set ? requested[i] == NM_TERNARY_TRUE : s->active),
			              _ethtool_feature_state_to_string (sbuf, sizeof (sbuf), s, do_set ? " currently:" : " before:"));

			if (   do_set
			    && (!s->available || s->never_changed)
			    && (s->active != (requested[i] == NM_TERNARY_TRUE))) {
				/* we request to change a flag which kernel reported as fixed.
				 * While the ethtool operation will silently succeed, mark the request
				 * as failure. */
				success = FALSE;
			}

			set_states[set_states_n].f_state = s;
			set_states[set_states_n].requested = requested[i];
			set_states_n++;
		}
	}

	if (set_states_n == 0) {
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: no feature requested",
		              ifindex,
		              "set-features");
		return TRUE;
	}

	sfeatures_len =   sizeof (struct ethtool_sfeatures)
	                + (NM_DIV_ROUND_UP (features->n_ss_features, 32U) * sizeof(sfeatures->features[0]));
	sfeatures = nm_malloc0_maybe_a (300, sfeatures_len, &sfeatures_free);
	sfeatures->cmd = ETHTOOL_SFEATURES;
	sfeatures->size = NM_DIV_ROUND_UP (features->n_ss_features, 32U);

	for (i = 0; i < set_states_n; i++) {
		const NMEthtoolFeatureState *s = set_states[i].f_state;
		guint i_block;
		guint32 i_flag;
		gboolean is_requested;

		i_block = s->idx_ss_features / 32u;
		i_flag = (guint32) (1u << (s->idx_ss_features % 32u));

		sfeatures->features[i_block].valid |= i_flag;

		if (do_set)
			is_requested = (set_states[i].requested == NM_TERNARY_TRUE);
		else
			is_requested = s->active;

		if (is_requested)
			sfeatures->features[i_block].requested |= i_flag;
		else
			sfeatures->features[i_block].requested &= ~i_flag;
	}

	r = _ethtool_call_handle (&shandle, sfeatures, sfeatures_len);
	if (r < 0) {
		success = FALSE;
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: failure setting features (%s)",
		              ifindex,
		              "set-features",
		              nm_strerror_native (-r));
		return FALSE;
	}

	nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: %s",
	              ifindex,
	              "set-features",
	              success
	                ? "successfully setting features"
	                : "at least some of the features were not successfully set");
	return success;
}

static gboolean
ethtool_get_coalesce (SocketHandle *shandle,
                      NMEthtoolCoalesceState *coalesce)
{
	struct ethtool_coalesce eth_data;

	eth_data.cmd = ETHTOOL_GCOALESCE;

	if (_ethtool_call_handle (shandle,
	                          &eth_data,
	                          sizeof (struct ethtool_coalesce)) != 0)
		return FALSE;

	*coalesce = (NMEthtoolCoalesceState) {
	    .s = {
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS)]          = eth_data.rx_coalesce_usecs,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES)]         = eth_data.rx_max_coalesced_frames,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS_IRQ)]      = eth_data.rx_coalesce_usecs_irq,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES_IRQ)]     = eth_data.rx_max_coalesced_frames_irq,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS)]          = eth_data.tx_coalesce_usecs,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES)]         = eth_data.tx_max_coalesced_frames,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS_IRQ)]      = eth_data.tx_coalesce_usecs_irq,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES_IRQ)]     = eth_data.tx_max_coalesced_frames_irq,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_STATS_BLOCK_USECS)] = eth_data.stats_block_coalesce_usecs,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_ADAPTIVE_RX)]       = eth_data.use_adaptive_rx_coalesce,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_ADAPTIVE_TX)]       = eth_data.use_adaptive_tx_coalesce,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_PKT_RATE_LOW)]      = eth_data.pkt_rate_low,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS_LOW)]      = eth_data.rx_coalesce_usecs_low,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES_LOW)]     = eth_data.rx_max_coalesced_frames_low,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS_LOW)]      = eth_data.tx_coalesce_usecs_low,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES_LOW)]     = eth_data.tx_max_coalesced_frames_low,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_PKT_RATE_HIGH)]     = eth_data.pkt_rate_high,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS_HIGH)]     = eth_data.rx_coalesce_usecs_high,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES_HIGH)]    = eth_data.rx_max_coalesced_frames_high,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS_HIGH)]     = eth_data.tx_coalesce_usecs_high,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES_HIGH)]    = eth_data.tx_max_coalesced_frames_high,
	        [_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_SAMPLE_INTERVAL)]   = eth_data.rate_sample_interval,
	    }
	};
	return TRUE;
}


gboolean
nmp_utils_ethtool_get_coalesce (int ifindex,
                                NMEthtoolCoalesceState *coalesce)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);

	g_return_val_if_fail (ifindex > 0, FALSE);
	g_return_val_if_fail (coalesce, FALSE);

	if (!ethtool_get_coalesce (&shandle, coalesce)) {
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: failure getting coalesce settings",
		              ifindex,
		              "get-coalesce");
		return FALSE;
	}

	nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: retrieved kernel coalesce settings",
	              ifindex,
	              "get-coalesce");
	return TRUE;
}

static gboolean
ethtool_set_coalesce (SocketHandle *shandle,
                      const NMEthtoolCoalesceState *coalesce)
{
	struct ethtool_coalesce eth_data;
	gboolean success;

	nm_assert (shandle);
	nm_assert (coalesce);

	eth_data = (struct ethtool_coalesce) {
		.cmd = ETHTOOL_SCOALESCE,
		.rx_coalesce_usecs            = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS)],
		.rx_max_coalesced_frames      = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES)],
		.rx_coalesce_usecs_irq        = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS_IRQ)],
		.rx_max_coalesced_frames_irq  = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES_IRQ)],
		.tx_coalesce_usecs            = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS)],
		.tx_max_coalesced_frames      = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES)],
		.tx_coalesce_usecs_irq        = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS_IRQ)],
		.tx_max_coalesced_frames_irq  = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES_IRQ)],
		.stats_block_coalesce_usecs   = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_STATS_BLOCK_USECS)],
		.use_adaptive_rx_coalesce     = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_ADAPTIVE_RX)],
		.use_adaptive_tx_coalesce     = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_ADAPTIVE_TX)],
		.pkt_rate_low                 = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_PKT_RATE_LOW)],
		.rx_coalesce_usecs_low        = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS_LOW)],
		.rx_max_coalesced_frames_low  = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES_LOW)],
		.tx_coalesce_usecs_low        = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS_LOW)],
		.tx_max_coalesced_frames_low  = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES_LOW)],
		.pkt_rate_high                = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_PKT_RATE_HIGH)],
		.rx_coalesce_usecs_high       = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_USECS_HIGH)],
		.rx_max_coalesced_frames_high = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_RX_FRAMES_HIGH)],
		.tx_coalesce_usecs_high       = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_USECS_HIGH)],
		.tx_max_coalesced_frames_high = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_TX_FRAMES_HIGH)],
		.rate_sample_interval         = coalesce->s[_NM_ETHTOOL_ID_COALESCE_AS_IDX (NM_ETHTOOL_ID_COALESCE_SAMPLE_INTERVAL)],
	};

	success = (_ethtool_call_handle (shandle,
	                                 &eth_data,
	                                 sizeof (struct ethtool_coalesce)) == 0);
	return success;
}

gboolean
nmp_utils_ethtool_set_coalesce (int ifindex,
                                const NMEthtoolCoalesceState *coalesce)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);

	g_return_val_if_fail (ifindex > 0, FALSE);
	g_return_val_if_fail (coalesce, FALSE);

	if (!ethtool_set_coalesce (&shandle, coalesce)) {
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: failure setting coalesce settings",
		              ifindex,
		              "set-coalesce");
		return FALSE;
	}

	nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: set kernel coalesce settings",
	              ifindex,
	              "set-coalesce");
	return TRUE;
}

static gboolean
ethtool_get_ring (SocketHandle *shandle,
                  NMEthtoolRingState *ring)
{
	struct ethtool_ringparam eth_data;

	eth_data.cmd = ETHTOOL_GRINGPARAM;

	if (_ethtool_call_handle (shandle,
	                          &eth_data,
	                          sizeof (struct ethtool_ringparam)) != 0)
		return FALSE;

	ring->rx_pending       = eth_data.rx_pending;
	ring->rx_jumbo_pending = eth_data.rx_jumbo_pending;
	ring->rx_mini_pending  = eth_data.rx_mini_pending;
	ring->tx_pending       = eth_data.tx_pending;

	return TRUE;
}

gboolean
nmp_utils_ethtool_get_ring (int ifindex,
                            NMEthtoolRingState *ring)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);

	g_return_val_if_fail (ifindex > 0, FALSE);
	g_return_val_if_fail (ring, FALSE);

	if (!ethtool_get_ring (&shandle, ring)) {
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: failure getting ring settings",
		              ifindex,
		              "get-ring");
		return FALSE;
	}

	nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: retrieved kernel ring settings",
	              ifindex,
	              "get-ring");
	return TRUE;
}

static gboolean
ethtool_set_ring (SocketHandle *shandle,
                  const NMEthtoolRingState *ring)
{
	gboolean success;
	struct ethtool_ringparam eth_data;

	g_return_val_if_fail (shandle, FALSE);
	g_return_val_if_fail (ring, FALSE);

	eth_data = (struct ethtool_ringparam) {
		.cmd = ETHTOOL_SRINGPARAM,
		.rx_pending       = ring->rx_pending,
		.rx_jumbo_pending = ring->rx_jumbo_pending,
		.rx_mini_pending  = ring->rx_mini_pending,
		.tx_pending       = ring->tx_pending,
	};

	success = (_ethtool_call_handle (shandle,
	                                 &eth_data,
	                                 sizeof (struct ethtool_ringparam)) == 0);
	return success;
}

gboolean
nmp_utils_ethtool_set_ring (int ifindex,
                            const NMEthtoolRingState *ring)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);

	g_return_val_if_fail (ifindex > 0, FALSE);
	g_return_val_if_fail (ring, FALSE);

	if (!ethtool_set_ring (&shandle, ring)) {
		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: failure setting ring settings",
		              ifindex,
		              "set-ring");
		return FALSE;
	}

	nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: set kernel ring settings",
	              ifindex,
	              "set-ring");
	return TRUE;
}

/*****************************************************************************/

gboolean
nmp_utils_ethtool_get_driver_info (int ifindex,
                                   NMPUtilsEthtoolDriverInfo *data)
{
	struct ethtool_drvinfo *drvinfo;

	G_STATIC_ASSERT_EXPR (sizeof (*data) == sizeof (*drvinfo));
	G_STATIC_ASSERT_EXPR (offsetof (NMPUtilsEthtoolDriverInfo, driver)     == offsetof (struct ethtool_drvinfo, driver));
	G_STATIC_ASSERT_EXPR (offsetof (NMPUtilsEthtoolDriverInfo, version)    == offsetof (struct ethtool_drvinfo, version));
	G_STATIC_ASSERT_EXPR (offsetof (NMPUtilsEthtoolDriverInfo, fw_version) == offsetof (struct ethtool_drvinfo, fw_version));
	G_STATIC_ASSERT_EXPR (sizeof (data->driver)     == sizeof (drvinfo->driver));
	G_STATIC_ASSERT_EXPR (sizeof (data->version)    == sizeof (drvinfo->version));
	G_STATIC_ASSERT_EXPR (sizeof (data->fw_version) == sizeof (drvinfo->fw_version));

	g_return_val_if_fail (ifindex > 0, FALSE);
	g_return_val_if_fail (data, FALSE);

	drvinfo = (struct ethtool_drvinfo *) data;
	*drvinfo = (struct ethtool_drvinfo) {
		.cmd = ETHTOOL_GDRVINFO,
	};
	return _ethtool_call_once (ifindex, drvinfo, sizeof (*drvinfo)) >= 0;
}

gboolean
nmp_utils_ethtool_get_permanent_address (int ifindex,
                                         guint8 *buf,
                                         size_t *length)
{
	struct {
		struct ethtool_perm_addr e;
		guint8 _extra_data[NM_UTILS_HWADDR_LEN_MAX + 1];
	} edata = {
		.e.cmd = ETHTOOL_GPERMADDR,
		.e.size = NM_UTILS_HWADDR_LEN_MAX,
	};
	const guint8 *pdata;

	guint i;

	g_return_val_if_fail (ifindex > 0, FALSE);

	if (_ethtool_call_once (ifindex, &edata, sizeof (edata)) < 0)
		return FALSE;

	if (edata.e.size > NM_UTILS_HWADDR_LEN_MAX)
		return FALSE;
	if (edata.e.size < 1)
		return FALSE;

	pdata = (const guint8 *) edata.e.data;

	if (NM_IN_SET (pdata[0], 0, 0xFF)) {
		/* Some drivers might return a permanent address of all zeros.
		 * Reject that (rh#1264024)
		 *
		 * Some drivers return a permanent address of all ones. Reject that too */
		for (i = 1; i < edata.e.size; i++) {
			if (pdata[0] != pdata[i])
				goto not_all_0or1;
		}
		return FALSE;
	}

not_all_0or1:
	memcpy (buf, pdata, edata.e.size);
	*length = edata.e.size;
	return TRUE;
}

gboolean
nmp_utils_ethtool_supports_carrier_detect (int ifindex)
{
	struct ethtool_cmd edata = { .cmd = ETHTOOL_GLINK };

	g_return_val_if_fail (ifindex > 0, FALSE);

	/* We ignore the result. If the ETHTOOL_GLINK call succeeded, then we
	 * assume the device supports carrier-detect, otherwise we assume it
	 * doesn't.
	 */
	return _ethtool_call_once (ifindex, &edata, sizeof (edata)) >= 0;
}

gboolean
nmp_utils_ethtool_supports_vlans (int ifindex)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);
	gs_free struct ethtool_gfeatures *features_free = NULL;
	struct ethtool_gfeatures *features;
	gsize features_len;
	int idx, block, bit, size;

	g_return_val_if_fail (ifindex > 0, FALSE);

	idx = ethtool_get_stringset_index (&shandle, ETH_SS_FEATURES, "vlan-challenged");
	if (idx < 0) {
		nm_log_dbg (LOGD_PLATFORM, "ethtool[%d]: vlan-challenged ethtool feature does not exist?", ifindex);
		return FALSE;
	}

	block = idx /  32;
	bit = idx % 32;
	size = block + 1;

	features_len =   sizeof (*features)
	               + (size * sizeof (struct ethtool_get_features_block));
	features = nm_malloc0_maybe_a (300, features_len, &features_free);
	features->cmd = ETHTOOL_GFEATURES;
	features->size = size;

	if (_ethtool_call_handle (&shandle, features, features_len) < 0)
		return FALSE;

	return !(features->features[block].active & (1 << bit));
}

int
nmp_utils_ethtool_get_peer_ifindex (int ifindex)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);
	gsize stats_len;
	gs_free struct ethtool_stats *stats_free = NULL;
	struct ethtool_stats *stats;
	int peer_ifindex_stat;

	g_return_val_if_fail (ifindex > 0, 0);

	peer_ifindex_stat = ethtool_get_stringset_index (&shandle, ETH_SS_STATS, "peer_ifindex");
	if (peer_ifindex_stat < 0) {
		nm_log_dbg (LOGD_PLATFORM, "ethtool[%d]: peer_ifindex stat does not exist?", ifindex);
		return FALSE;
	}

	stats_len = sizeof (*stats) + (peer_ifindex_stat + 1) * sizeof (guint64);
	stats = nm_malloc0_maybe_a (300, stats_len, &stats_free);
	stats->cmd = ETHTOOL_GSTATS;
	stats->n_stats = peer_ifindex_stat + 1;
	if (_ethtool_call_handle (&shandle, stats, stats_len) < 0)
		return 0;

	return stats->data[peer_ifindex_stat];
}

gboolean
nmp_utils_ethtool_get_wake_on_lan (int ifindex)
{
	struct ethtool_wolinfo wol = {
		.cmd = ETHTOOL_GWOL,
	};

	g_return_val_if_fail (ifindex > 0, FALSE);

	if (_ethtool_call_once (ifindex, &wol, sizeof (wol)) < 0)
		return FALSE;

	return wol.wolopts != 0;
}

gboolean
nmp_utils_ethtool_get_link_settings (int ifindex,
                                     gboolean *out_autoneg,
                                     guint32 *out_speed,
                                     NMPlatformLinkDuplexType *out_duplex)
{
	struct ethtool_cmd edata = {
		.cmd = ETHTOOL_GSET,
	};

	g_return_val_if_fail (ifindex > 0, FALSE);

	if (_ethtool_call_once (ifindex, &edata, sizeof (edata)) < 0)
		return FALSE;

	NM_SET_OUT (out_autoneg, (edata.autoneg == AUTONEG_ENABLE));

	if (out_speed) {
		guint32 speed;

		speed = ethtool_cmd_speed (&edata);
		if (speed == G_MAXUINT16 || speed == G_MAXUINT32)
			speed = 0;

		*out_speed = speed;
	}

	if (out_duplex) {
		switch (edata.duplex) {
		case DUPLEX_HALF:
			*out_duplex = NM_PLATFORM_LINK_DUPLEX_HALF;
			break;
		case DUPLEX_FULL:
			*out_duplex = NM_PLATFORM_LINK_DUPLEX_FULL;
			break;
		default: /* DUPLEX_UNKNOWN */
			*out_duplex = NM_PLATFORM_LINK_DUPLEX_UNKNOWN;
			break;
		}
	}

	return TRUE;
}


#define ADVERTISED_INVALID 0
#define BASET_ALL_MODES (  ADVERTISED_10baseT_Half \
                         | ADVERTISED_10baseT_Full \
                         | ADVERTISED_100baseT_Half \
                         | ADVERTISED_100baseT_Full \
                         | ADVERTISED_1000baseT_Half \
                         | ADVERTISED_1000baseT_Full \
                         | ADVERTISED_10000baseT_Full )

static guint32
get_baset_mode (guint32 speed, NMPlatformLinkDuplexType duplex)
{
	if (duplex == NM_PLATFORM_LINK_DUPLEX_UNKNOWN)
		return ADVERTISED_INVALID;

	if (duplex == NM_PLATFORM_LINK_DUPLEX_HALF) {
		switch (speed) {
		case 10: return ADVERTISED_10baseT_Half;
		case 100: return ADVERTISED_100baseT_Half;
		case 1000: return ADVERTISED_1000baseT_Half;
		default: return ADVERTISED_INVALID;
		}
	} else {
		switch (speed) {
		case 10: return ADVERTISED_10baseT_Full;
		case 100: return ADVERTISED_100baseT_Full;
		case 1000: return ADVERTISED_1000baseT_Full;
		case 10000: return ADVERTISED_10000baseT_Full;
		default: return ADVERTISED_INVALID;
		}
	}
}

gboolean
nmp_utils_ethtool_set_link_settings (int ifindex,
                                     gboolean autoneg,
                                     guint32 speed,
                                     NMPlatformLinkDuplexType duplex)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);
	struct ethtool_cmd edata = {
		.cmd = ETHTOOL_GSET,
	};

	g_return_val_if_fail (ifindex > 0, FALSE);
	g_return_val_if_fail (   (speed && duplex != NM_PLATFORM_LINK_DUPLEX_UNKNOWN)
	                      || (!speed && duplex == NM_PLATFORM_LINK_DUPLEX_UNKNOWN), FALSE);

	/* retrieve first current settings */
	if (_ethtool_call_handle (&shandle, &edata, sizeof (edata)) < 0)
		return FALSE;

	/* FIXME: try first new ETHTOOL_GLINKSETTINGS/SLINKSETTINGS API
	 * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3f1ac7a700d039c61d8d8b99f28d605d489a60cf
	 */

	/* then change the needed ones */
	edata.cmd = ETHTOOL_SSET;
	if (autoneg) {
		edata.autoneg = AUTONEG_ENABLE;
		if (!speed)
			edata.advertising = edata.supported;
		else {
			guint32 mode;

			mode = get_baset_mode (speed, duplex);

			if (!mode) {
				nm_log_trace (LOGD_PLATFORM,
				              "ethtool[%d]: %uBASE-T %s duplex mode cannot be advertised",
				              ifindex,
				              speed,
				              nm_platform_link_duplex_type_to_string (duplex));
				return FALSE;
			}
			if (!(edata.supported & mode)) {
				nm_log_trace (LOGD_PLATFORM,
				              "ethtool[%d]: device does not support %uBASE-T %s duplex mode",
				              ifindex,
				              speed,
				              nm_platform_link_duplex_type_to_string (duplex));
				return FALSE;
			}
			edata.advertising = (edata.supported & ~BASET_ALL_MODES) | mode;
		}
	} else {
		edata.autoneg = AUTONEG_DISABLE;

		if (speed)
			ethtool_cmd_speed_set (&edata, speed);

		switch (duplex) {
		case NM_PLATFORM_LINK_DUPLEX_HALF:
			edata.duplex = DUPLEX_HALF;
			break;
		case NM_PLATFORM_LINK_DUPLEX_FULL:
			edata.duplex = DUPLEX_FULL;
			break;
		case NM_PLATFORM_LINK_DUPLEX_UNKNOWN:
			break;
		default:
			g_return_val_if_reached (FALSE);
		}
	}

	return _ethtool_call_handle (&shandle, &edata, sizeof (edata)) >= 0;
}

gboolean
nmp_utils_ethtool_set_wake_on_lan (int ifindex,
                                   NMSettingWiredWakeOnLan wol,
                                   const char *wol_password)
{
	struct ethtool_wolinfo wol_info = {
		.cmd = ETHTOOL_SWOL,
		.wolopts = 0,
	};

	g_return_val_if_fail (ifindex > 0, FALSE);

	if (wol == NM_SETTING_WIRED_WAKE_ON_LAN_IGNORE)
		return TRUE;

	nm_log_dbg (LOGD_PLATFORM, "ethtool[%d]: setting Wake-on-LAN options 0x%x, password '%s'",
	            ifindex, (unsigned) wol, wol_password);

	if (NM_FLAGS_HAS (wol, NM_SETTING_WIRED_WAKE_ON_LAN_PHY))
		wol_info.wolopts |= WAKE_PHY;
	if (NM_FLAGS_HAS (wol, NM_SETTING_WIRED_WAKE_ON_LAN_UNICAST))
		wol_info.wolopts |= WAKE_UCAST;
	if (NM_FLAGS_HAS (wol, NM_SETTING_WIRED_WAKE_ON_LAN_MULTICAST))
		wol_info.wolopts |= WAKE_MCAST;
	if (NM_FLAGS_HAS (wol, NM_SETTING_WIRED_WAKE_ON_LAN_BROADCAST))
		wol_info.wolopts |= WAKE_BCAST;
	if (NM_FLAGS_HAS (wol, NM_SETTING_WIRED_WAKE_ON_LAN_ARP))
		wol_info.wolopts |= WAKE_ARP;
	if (NM_FLAGS_HAS (wol, NM_SETTING_WIRED_WAKE_ON_LAN_MAGIC))
		wol_info.wolopts |= WAKE_MAGIC;

	if (wol_password) {
		if (!nm_utils_hwaddr_aton (wol_password, wol_info.sopass, ETH_ALEN)) {
			nm_log_dbg (LOGD_PLATFORM, "ethtool[%d]: couldn't parse Wake-on-LAN password '%s'", ifindex, wol_password);
			return FALSE;
		}
		wol_info.wolopts |= WAKE_MAGICSECURE;
	}

	return _ethtool_call_once (ifindex, &wol_info, sizeof (wol_info)) >= 0;
}

/******************************************************************************
 * mii
 *****************************************************************************/

gboolean
nmp_utils_mii_supports_carrier_detect (int ifindex)
{
	nm_auto_socket_handle SocketHandle shandle = SOCKET_HANDLE_INIT (ifindex);
	int r;
	struct ifreq ifr;
	struct mii_ioctl_data *mii;

	g_return_val_if_fail (ifindex > 0, FALSE);

	r = _ioctl_call ("mii",
	                 "SIOCGMIIPHY",
	                 SIOCGMIIPHY,
	                 shandle.ifindex,
	                 &shandle.fd,
	                 shandle.ifname,
	                 IOCTL_CALL_DATA_TYPE_NONE,
	                 NULL,
	                 0,
	                 &ifr);
	if (r < 0)
		return FALSE;

	/* If we can read the BMSR register, we assume that the card supports MII link detection */
	mii = (struct mii_ioctl_data *) &ifr.ifr_ifru;
	mii->reg_num = MII_BMSR;

	r = _ioctl_call ("mii",
	                 "SIOCGMIIREG",
	                 SIOCGMIIREG,
	                 shandle.ifindex,
	                 &shandle.fd,
	                 shandle.ifname,
	                 IOCTL_CALL_DATA_TYPE_IFRU,
	                 mii,
	                 sizeof (*mii),
	                 &ifr);
	if (r < 0)
		return FALSE;

	mii = (struct mii_ioctl_data *) &ifr.ifr_ifru;
	nm_log_trace (LOGD_PLATFORM, "mii[%d,%s]: carrier-detect yes: SIOCGMIIREG result 0x%X", ifindex, shandle.ifname, mii->val_out);
	return TRUE;
}

/******************************************************************************
 * udev
 *****************************************************************************/

const char *
nmp_utils_udev_get_driver (struct udev_device *udevice)
{
	struct udev_device *parent = NULL, *grandparent = NULL;
	const char *driver, *subsys;

	driver = udev_device_get_driver (udevice);
	if (driver)
		goto out;

	/* Try the parent */
	parent = udev_device_get_parent (udevice);
	if (parent) {
		driver = udev_device_get_driver (parent);
		if (!driver) {
			/* Try the grandparent if it's an ibmebus device or if the
			 * subsys is NULL which usually indicates some sort of
			 * platform device like a 'gadget' net interface.
			 */
			subsys = udev_device_get_subsystem (parent);
			if (   (g_strcmp0 (subsys, "ibmebus") == 0)
			    || (subsys == NULL)) {
				grandparent = udev_device_get_parent (parent);
				if (grandparent)
					driver = udev_device_get_driver (grandparent);
			}
		}
	}

out:
	/* Intern the string so we don't have to worry about memory
	 * management in NMPlatformLink. */
	return g_intern_string (driver);
}

/******************************************************************************
 * utils
 *****************************************************************************/

NMIPConfigSource
nmp_utils_ip_config_source_from_rtprot (guint8 rtprot)
{
	return ((int) rtprot) + 1;
}

NMIPConfigSource
nmp_utils_ip_config_source_round_trip_rtprot (NMIPConfigSource source)
{
	/* when adding a route to kernel for a give @source, the resulting route
	 * will be put into the cache with a source of NM_IP_CONFIG_SOURCE_RTPROT_*.
	 * This function returns that. */
	return nmp_utils_ip_config_source_from_rtprot (nmp_utils_ip_config_source_coerce_to_rtprot (source));
}

guint8
nmp_utils_ip_config_source_coerce_to_rtprot (NMIPConfigSource source)
{
	/* when adding a route to kernel, we coerce the @source field
	 * to rtm_protocol. This is not lossless as we map different
	 * source values to the same RTPROT uint8 value. */
	if (source <= NM_IP_CONFIG_SOURCE_UNKNOWN)
		return RTPROT_UNSPEC;

	if (source <= _NM_IP_CONFIG_SOURCE_RTPROT_LAST)
		return source - 1;

	switch (source) {
	case NM_IP_CONFIG_SOURCE_KERNEL:
		return RTPROT_KERNEL;
	case NM_IP_CONFIG_SOURCE_IP6LL:
		return RTPROT_KERNEL;
	case NM_IP_CONFIG_SOURCE_DHCP:
		return RTPROT_DHCP;
	case NM_IP_CONFIG_SOURCE_NDISC:
		return RTPROT_RA;

	default:
		return RTPROT_STATIC;
	}
}

NMIPConfigSource
nmp_utils_ip_config_source_coerce_from_rtprot (NMIPConfigSource source)
{
	/* When we receive a route from kernel and put it into the platform cache,
	 * we preserve the protocol field by converting it to a NMIPConfigSource
	 * via nmp_utils_ip_config_source_from_rtprot().
	 *
	 * However, that is not the inverse of nmp_utils_ip_config_source_coerce_to_rtprot().
	 * Instead, to go back to the original value, you need another step:
	 *   nmp_utils_ip_config_source_coerce_from_rtprot (nmp_utils_ip_config_source_from_rtprot (rtprot)).
	 *
	 * This might partly restore the original source value, but of course that
	 * is not really possible because nmp_utils_ip_config_source_coerce_to_rtprot()
	 * is not injective.
	 * */
	switch (source) {
	case NM_IP_CONFIG_SOURCE_RTPROT_UNSPEC:
		return NM_IP_CONFIG_SOURCE_UNKNOWN;

	case NM_IP_CONFIG_SOURCE_RTPROT_KERNEL:
	case NM_IP_CONFIG_SOURCE_RTPROT_REDIRECT:
		return NM_IP_CONFIG_SOURCE_KERNEL;

	case NM_IP_CONFIG_SOURCE_RTPROT_RA:
		return NM_IP_CONFIG_SOURCE_NDISC;

	case NM_IP_CONFIG_SOURCE_RTPROT_DHCP:
		return NM_IP_CONFIG_SOURCE_DHCP;

	default:
		return NM_IP_CONFIG_SOURCE_USER;
	}
}

const char *
nmp_utils_ip_config_source_to_string (NMIPConfigSource source, char *buf, gsize len)
{
	const char *s = NULL;
	nm_utils_to_string_buffer_init (&buf, &len); \

	if (!len)
		return buf;

	switch (source) {
	case NM_IP_CONFIG_SOURCE_UNKNOWN:         s = "unknown"; break;

	case NM_IP_CONFIG_SOURCE_RTPROT_UNSPEC:   s = "rt-unspec"; break;
	case NM_IP_CONFIG_SOURCE_RTPROT_REDIRECT: s = "rt-redirect"; break;
	case NM_IP_CONFIG_SOURCE_RTPROT_KERNEL:   s = "rt-kernel"; break;
	case NM_IP_CONFIG_SOURCE_RTPROT_BOOT:     s = "rt-boot"; break;
	case NM_IP_CONFIG_SOURCE_RTPROT_STATIC:   s = "rt-static"; break;
	case NM_IP_CONFIG_SOURCE_RTPROT_DHCP:     s = "rt-dhcp"; break;
	case NM_IP_CONFIG_SOURCE_RTPROT_RA:       s = "rt-ra"; break;

	case NM_IP_CONFIG_SOURCE_KERNEL:          s = "kernel"; break;
	case NM_IP_CONFIG_SOURCE_SHARED:          s = "shared"; break;
	case NM_IP_CONFIG_SOURCE_IP4LL:           s = "ipv4ll"; break;
	case NM_IP_CONFIG_SOURCE_IP6LL:           s = "ipv6ll"; break;
	case NM_IP_CONFIG_SOURCE_PPP:             s = "ppp"; break;
	case NM_IP_CONFIG_SOURCE_WWAN:            s = "wwan"; break;
	case NM_IP_CONFIG_SOURCE_VPN:             s = "vpn"; break;
	case NM_IP_CONFIG_SOURCE_DHCP:            s = "dhcp"; break;
	case NM_IP_CONFIG_SOURCE_NDISC:           s = "ndisc"; break;
	case NM_IP_CONFIG_SOURCE_USER:            s = "user"; break;
	default:
		break;
	}

	if (source >= 1 && source <= 0x100) {
		if (s)
			g_snprintf (buf, len, "%s", s);
		else
			g_snprintf (buf, len, "rt-%d", ((int) source) - 1);
	} else {
		if (s)
			g_strlcpy (buf, s, len);
		else
			g_snprintf (buf, len, "(%d)", source);
	}
	return buf;
}

/**
 * nmp_utils_sysctl_open_netdir:
 * @ifindex: the ifindex for which to open "/sys/class/net/%s"
 * @ifname_guess: (allow-none): optional argument, if present used as initial
 *   guess as the current name for @ifindex. If guessed right,
 *   it saves an additional if_indextoname() call.
 * @out_ifname: (allow-none): if present, must be at least IFNAMSIZ
 *   characters. On success, this will contain the actual ifname
 *   found while opening the directory.
 *
 * Returns: a negative value on failure, on success returns the open fd
 *   to the "/sys/class/net/%s" directory for @ifindex.
 */
int
nmp_utils_sysctl_open_netdir (int ifindex,
                              const char *ifname_guess,
                              char *out_ifname)
{
	#define SYS_CLASS_NET "/sys/class/net/"
	const char *ifname = ifname_guess;
	char ifname_buf_last_try[IFNAMSIZ];
	char ifname_buf[IFNAMSIZ];
	guint try_count = 0;
	char sysdir[NM_STRLEN (SYS_CLASS_NET) + IFNAMSIZ] = SYS_CLASS_NET;
	char fd_buf[256];
	ssize_t nn;

	g_return_val_if_fail (ifindex >= 0, -1);

	ifname_buf_last_try[0] = '\0';

	for (try_count = 0; try_count < 10; try_count++, ifname = NULL) {
		nm_auto_close int fd_dir = -1;
		nm_auto_close int fd_ifindex = -1;

		if (!ifname) {
			ifname = nmp_utils_if_indextoname (ifindex, ifname_buf);
			if (!ifname)
				return -1;
		}

		nm_assert (nm_utils_ifname_valid_kernel (ifname, NULL));

		if (g_strlcpy (&sysdir[NM_STRLEN (SYS_CLASS_NET)], ifname, IFNAMSIZ) >= IFNAMSIZ)
			g_return_val_if_reached (-1);

		/* we only retry, if the name changed since previous attempt.
		 * Hence, it is extremely unlikely that this loop runes until the
		 * end of the @try_count. */
		if (nm_streq (ifname, ifname_buf_last_try))
			return -1;
		strcpy (ifname_buf_last_try, ifname);

		fd_dir = open (sysdir, O_DIRECTORY | O_CLOEXEC);
		if (fd_dir < 0)
			continue;

		fd_ifindex = openat (fd_dir, "ifindex", O_CLOEXEC);
		if (fd_ifindex < 0)
			continue;

		nn = nm_utils_fd_read_loop (fd_ifindex, fd_buf, sizeof (fd_buf) - 2, FALSE);
		if (nn <= 0)
			continue;
		fd_buf[nn] = '\0';

		if (ifindex != (int) _nm_utils_ascii_str_to_int64 (fd_buf, 10, 1, G_MAXINT, -1))
			continue;

		if (out_ifname)
			strcpy (out_ifname, ifname);

		return nm_steal_fd (&fd_dir);
	}

	return -1;
}