Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

7 files changed, 1684 insertions, 0 deletions

diff --git a/src/udev/net/ethtool-util.c b/src/udev/net/ethtool-util.c
new file mode 100644
index 0000000..0dcec03
--- /dev/null
+++ b/src/udev/net/ethtool-util.c
@@ -0,0 +1,787 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <linux/ethtool.h>
+#include <linux/sockios.h>
+
+#include "conf-parser.h"
+#include "ethtool-util.h"
+#include "link-config.h"
+#include "log.h"
+#include "missing.h"
+#include "socket-util.h"
+#include "string-table.h"
+#include "strxcpyx.h"
+#include "util.h"
+
+static const char* const duplex_table[_DUP_MAX] = {
+        [DUP_FULL] = "full",
+        [DUP_HALF] = "half"
+};
+
+DEFINE_STRING_TABLE_LOOKUP(duplex, Duplex);
+DEFINE_CONFIG_PARSE_ENUM(config_parse_duplex, duplex, Duplex, "Failed to parse duplex setting");
+
+static const char* const wol_table[_WOL_MAX] = {
+        [WOL_PHY]         = "phy",
+        [WOL_UCAST]       = "unicast",
+        [WOL_MCAST]       = "multicast",
+        [WOL_BCAST]       = "broadcast",
+        [WOL_ARP]         = "arp",
+        [WOL_MAGIC]       = "magic",
+        [WOL_MAGICSECURE] = "secureon",
+        [WOL_OFF]         = "off",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(wol, WakeOnLan);
+DEFINE_CONFIG_PARSE_ENUM(config_parse_wol, wol, WakeOnLan, "Failed to parse WakeOnLan setting");
+
+static const char* const port_table[] = {
+        [NET_DEV_PORT_TP]     = "tp",
+        [NET_DEV_PORT_AUI]    = "aui",
+        [NET_DEV_PORT_MII]    = "mii",
+        [NET_DEV_PORT_FIBRE]  = "fibre",
+        [NET_DEV_PORT_BNC]    = "bnc",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(port, NetDevPort);
+DEFINE_CONFIG_PARSE_ENUM(config_parse_port, port, NetDevPort, "Failed to parse Port setting");
+
+static const char* const netdev_feature_table[_NET_DEV_FEAT_MAX] = {
+        [NET_DEV_FEAT_GSO]  = "tx-generic-segmentation",
+        [NET_DEV_FEAT_GRO]  = "rx-gro",
+        [NET_DEV_FEAT_LRO]  = "rx-lro",
+        [NET_DEV_FEAT_TSO]  = "tx-tcp-segmentation",
+        [NET_DEV_FEAT_TSO6] = "tx-tcp6-segmentation",
+};
+
+static const char* const ethtool_link_mode_bit_table[] = {
+        [ETHTOOL_LINK_MODE_10baseT_Half_BIT]           = "10baset-half",
+        [ETHTOOL_LINK_MODE_10baseT_Full_BIT]           = "10baset-full",
+        [ETHTOOL_LINK_MODE_100baseT_Half_BIT]          = "100baset-half",
+        [ETHTOOL_LINK_MODE_100baseT_Full_BIT]          = "100baset-full",
+        [ETHTOOL_LINK_MODE_1000baseT_Half_BIT]         = "1000baset-half",
+        [ETHTOOL_LINK_MODE_1000baseT_Full_BIT]         = "1000baset-full",
+        [ETHTOOL_LINK_MODE_Autoneg_BIT]                = "autonegotiation",
+        [ETHTOOL_LINK_MODE_TP_BIT]                     = "tp",
+        [ETHTOOL_LINK_MODE_AUI_BIT]                    = "aui",
+        [ETHTOOL_LINK_MODE_MII_BIT]                    = "mii",
+        [ETHTOOL_LINK_MODE_FIBRE_BIT]                  = "fibre",
+        [ETHTOOL_LINK_MODE_BNC_BIT]                    = "bnc",
+        [ETHTOOL_LINK_MODE_10000baseT_Full_BIT]        = "10000baset-full",
+        [ETHTOOL_LINK_MODE_Pause_BIT]                  = "pause",
+        [ETHTOOL_LINK_MODE_Asym_Pause_BIT]             = "asym-pause",
+        [ETHTOOL_LINK_MODE_2500baseX_Full_BIT]         = "2500basex-full",
+        [ETHTOOL_LINK_MODE_Backplane_BIT]              = "backplane",
+        [ETHTOOL_LINK_MODE_1000baseKX_Full_BIT]        = "1000basekx-full",
+        [ETHTOOL_LINK_MODE_10000baseKX4_Full_BIT]      = "10000basekx4-full",
+        [ETHTOOL_LINK_MODE_10000baseKR_Full_BIT]       = "10000basekr-full",
+        [ETHTOOL_LINK_MODE_10000baseR_FEC_BIT]         = "10000baser-fec",
+        [ETHTOOL_LINK_MODE_20000baseMLD2_Full_BIT]     = "20000basemld2-full",
+        [ETHTOOL_LINK_MODE_20000baseKR2_Full_BIT]      = "20000basekr2-full",
+        [ETHTOOL_LINK_MODE_40000baseKR4_Full_BIT]      = "40000basekr4-full",
+        [ETHTOOL_LINK_MODE_40000baseCR4_Full_BIT]      = "40000basecr4-full",
+        [ETHTOOL_LINK_MODE_40000baseSR4_Full_BIT]      = "40000basesr4-full",
+        [ETHTOOL_LINK_MODE_40000baseLR4_Full_BIT]      = "40000baselr4-full",
+        [ETHTOOL_LINK_MODE_56000baseKR4_Full_BIT]      = "56000basekr4-full",
+        [ETHTOOL_LINK_MODE_56000baseCR4_Full_BIT]      = "56000basecr4-full",
+        [ETHTOOL_LINK_MODE_56000baseSR4_Full_BIT]      = "56000basesr4-full",
+        [ETHTOOL_LINK_MODE_56000baseLR4_Full_BIT]      = "56000baselr4-full",
+        [ETHTOOL_LINK_MODE_25000baseCR_Full_BIT]       = "25000basecr-full",
+        [ETHTOOL_LINK_MODE_25000baseKR_Full_BIT]       = "25000basekr-full",
+        [ETHTOOL_LINK_MODE_25000baseSR_Full_BIT]       = "25000basesr-full",
+        [ETHTOOL_LINK_MODE_50000baseCR2_Full_BIT]      = "50000basecr2-full",
+        [ETHTOOL_LINK_MODE_50000baseKR2_Full_BIT]      = "50000basekr2-full",
+        [ETHTOOL_LINK_MODE_100000baseKR4_Full_BIT]     = "100000basekr4-full",
+        [ETHTOOL_LINK_MODE_100000baseSR4_Full_BIT]     = "100000basesr4-full",
+        [ETHTOOL_LINK_MODE_100000baseCR4_Full_BIT]     = "100000basecr4-full",
+        [ETHTOOL_LINK_MODE_100000baseLR4_ER4_Full_BIT] = "100000baselr4-er4-full",
+        [ETHTOOL_LINK_MODE_50000baseSR2_Full_BIT]      = "50000basesr2-full",
+        [ETHTOOL_LINK_MODE_1000baseX_Full_BIT]         = "1000basex-full",
+        [ETHTOOL_LINK_MODE_10000baseCR_Full_BIT]       = "10000basecr-full",
+        [ETHTOOL_LINK_MODE_10000baseSR_Full_BIT]       = "10000basesr-full",
+        [ETHTOOL_LINK_MODE_10000baseLR_Full_BIT]       = "10000baselr-full",
+        [ETHTOOL_LINK_MODE_10000baseLRM_Full_BIT]      = "10000baselrm-full",
+        [ETHTOOL_LINK_MODE_10000baseER_Full_BIT]       = "10000baseer-full",
+        [ETHTOOL_LINK_MODE_2500baseT_Full_BIT]         = "2500baset-full",
+        [ETHTOOL_LINK_MODE_5000baseT_Full_BIT]         = "5000baset-full",
+        [ETHTOOL_LINK_MODE_FEC_NONE_BIT]               = "fec-none",
+        [ETHTOOL_LINK_MODE_FEC_RS_BIT]                 = "fec-rs",
+        [ETHTOOL_LINK_MODE_FEC_BASER_BIT]              = "fec-baser",
+};
+/* Make sure the array is large enough to fit all bits */
+assert_cc((ELEMENTSOF(ethtool_link_mode_bit_table)-1) / 32 < ELEMENTSOF(((struct link_config){}).advertise));
+
+DEFINE_STRING_TABLE_LOOKUP(ethtool_link_mode_bit, enum ethtool_link_mode_bit_indices);
+
+int ethtool_connect(int *ret) {
+        int fd;
+
+        assert_return(ret, -EINVAL);
+
+        fd = socket_ioctl_fd();
+        if (fd < 0)
+                return fd;
+
+        *ret = fd;
+
+        return 0;
+}
+
+int ethtool_get_driver(int *fd, const char *ifname, char **ret) {
+        struct ethtool_drvinfo ecmd = {
+                .cmd = ETHTOOL_GDRVINFO
+        };
+        struct ifreq ifr = {
+                .ifr_data = (void*) &ecmd
+        };
+        char *d;
+        int r;
+
+        if (*fd < 0) {
+                r = ethtool_connect(fd);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: could not connect to ethtool: %m");
+        }
+
+        strscpy(ifr.ifr_name, IFNAMSIZ, ifname);
+
+        r = ioctl(*fd, SIOCETHTOOL, &ifr);
+        if (r < 0)
+                return -errno;
+
+        d = strdup(ecmd.driver);
+        if (!d)
+                return -ENOMEM;
+
+        *ret = d;
+        return 0;
+}
+
+int ethtool_set_speed(int *fd, const char *ifname, unsigned speed, Duplex duplex) {
+        struct ethtool_cmd ecmd = {
+                .cmd = ETHTOOL_GSET
+        };
+        struct ifreq ifr = {
+                .ifr_data = (void*) &ecmd
+        };
+        bool need_update = false;
+        int r;
+
+        if (speed == 0 && duplex == _DUP_INVALID)
+                return 0;
+
+        if (*fd < 0) {
+                r = ethtool_connect(fd);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: could not connect to ethtool: %m");
+        }
+
+        strscpy(ifr.ifr_name, IFNAMSIZ, ifname);
+
+        r = ioctl(*fd, SIOCETHTOOL, &ifr);
+        if (r < 0)
+                return -errno;
+
+        if (ethtool_cmd_speed(&ecmd) != speed) {
+                ethtool_cmd_speed_set(&ecmd, speed);
+                need_update = true;
+        }
+
+        switch (duplex) {
+                case DUP_HALF:
+                        if (ecmd.duplex != DUPLEX_HALF) {
+                                ecmd.duplex = DUPLEX_HALF;
+                                need_update = true;
+                        }
+                        break;
+                case DUP_FULL:
+                        if (ecmd.duplex != DUPLEX_FULL) {
+                                ecmd.duplex = DUPLEX_FULL;
+                                need_update = true;
+                        }
+                        break;
+                default:
+                        break;
+        }
+
+        if (need_update) {
+                ecmd.cmd = ETHTOOL_SSET;
+
+                r = ioctl(*fd, SIOCETHTOOL, &ifr);
+                if (r < 0)
+                        return -errno;
+        }
+
+        return 0;
+}
+
+int ethtool_set_wol(int *fd, const char *ifname, WakeOnLan wol) {
+        struct ethtool_wolinfo ecmd = {
+                .cmd = ETHTOOL_GWOL
+        };
+        struct ifreq ifr = {
+                .ifr_data = (void*) &ecmd
+        };
+        bool need_update = false;
+        int r;
+
+        if (wol == _WOL_INVALID)
+                return 0;
+
+        if (*fd < 0) {
+                r = ethtool_connect(fd);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: could not connect to ethtool: %m");
+        }
+
+        strscpy(ifr.ifr_name, IFNAMSIZ, ifname);
+
+        r = ioctl(*fd, SIOCETHTOOL, &ifr);
+        if (r < 0)
+                return -errno;
+
+        switch (wol) {
+        case WOL_PHY:
+                if (ecmd.wolopts != WAKE_PHY) {
+                        ecmd.wolopts = WAKE_PHY;
+                        need_update = true;
+                }
+                break;
+        case WOL_UCAST:
+                if (ecmd.wolopts != WAKE_UCAST) {
+                        ecmd.wolopts = WAKE_UCAST;
+                        need_update = true;
+                }
+                break;
+        case WOL_MCAST:
+                if (ecmd.wolopts != WAKE_MCAST) {
+                        ecmd.wolopts = WAKE_MCAST;
+                        need_update = true;
+                }
+                break;
+        case WOL_BCAST:
+                if (ecmd.wolopts != WAKE_BCAST) {
+                        ecmd.wolopts = WAKE_BCAST;
+                        need_update = true;
+                }
+                break;
+        case WOL_ARP:
+                if (ecmd.wolopts != WAKE_ARP) {
+                        ecmd.wolopts = WAKE_ARP;
+                        need_update = true;
+                }
+                break;
+        case WOL_MAGIC:
+                if (ecmd.wolopts != WAKE_MAGIC) {
+                        ecmd.wolopts = WAKE_MAGIC;
+                        need_update = true;
+                }
+                break;
+        case WOL_MAGICSECURE:
+                if (ecmd.wolopts != WAKE_MAGICSECURE) {
+                        ecmd.wolopts = WAKE_MAGICSECURE;
+                        need_update = true;
+                }
+                break;
+        case WOL_OFF:
+                if (ecmd.wolopts != 0) {
+                        ecmd.wolopts = 0;
+                        need_update = true;
+                }
+                break;
+        default:
+                break;
+        }
+
+        if (need_update) {
+                ecmd.cmd = ETHTOOL_SWOL;
+
+                r = ioctl(*fd, SIOCETHTOOL, &ifr);
+                if (r < 0)
+                        return -errno;
+        }
+
+        return 0;
+}
+
+static int get_stringset(int fd, struct ifreq *ifr, int stringset_id, struct ethtool_gstrings **gstrings) {
+        _cleanup_free_ struct ethtool_gstrings *strings = NULL;
+        struct {
+                struct ethtool_sset_info info;
+                uint32_t space;
+        } buffer = {
+                .info = {
+                        .cmd = ETHTOOL_GSSET_INFO,
+                        .sset_mask = UINT64_C(1) << stringset_id,
+                },
+        };
+        unsigned len;
+        int r;
+
+        ifr->ifr_data = (void *) &buffer.info;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        if (!buffer.info.sset_mask)
+                return -EINVAL;
+
+        len = buffer.info.data[0];
+
+        strings = malloc0(sizeof(struct ethtool_gstrings) + len * ETH_GSTRING_LEN);
+        if (!strings)
+                return -ENOMEM;
+
+        strings->cmd = ETHTOOL_GSTRINGS;
+        strings->string_set = stringset_id;
+        strings->len = len;
+
+        ifr->ifr_data = (void *) strings;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        *gstrings = TAKE_PTR(strings);
+
+        return 0;
+}
+
+static int find_feature_index(struct ethtool_gstrings *strings, const char *feature) {
+        unsigned i;
+
+        for (i = 0; i < strings->len; i++) {
+                if (streq((char *) &strings->data[i * ETH_GSTRING_LEN], feature))
+                        return i;
+        }
+
+        return -1;
+}
+
+int ethtool_set_features(int *fd, const char *ifname, int *features) {
+        _cleanup_free_ struct ethtool_gstrings *strings = NULL;
+        struct ethtool_sfeatures *sfeatures;
+        int block, bit, i, r;
+        struct ifreq ifr = {};
+
+        if (*fd < 0) {
+                r = ethtool_connect(fd);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: could not connect to ethtool: %m");
+        }
+
+        strscpy(ifr.ifr_name, IFNAMSIZ, ifname);
+
+        r = get_stringset(*fd, &ifr, ETH_SS_FEATURES, &strings);
+        if (r < 0)
+                return log_warning_errno(r, "link_config: could not get ethtool features for %s", ifname);
+
+        sfeatures = alloca0(sizeof(struct ethtool_sfeatures) + DIV_ROUND_UP(strings->len, 32U) * sizeof(sfeatures->features[0]));
+        sfeatures->cmd = ETHTOOL_SFEATURES;
+        sfeatures->size = DIV_ROUND_UP(strings->len, 32U);
+
+        for (i = 0; i < _NET_DEV_FEAT_MAX; i++) {
+
+                if (features[i] != -1) {
+
+                        r = find_feature_index(strings, netdev_feature_table[i]);
+                        if (r < 0) {
+                                log_warning_errno(r, "link_config: could not find feature: %s", netdev_feature_table[i]);
+                                continue;
+                        }
+
+                        block = r / 32;
+                        bit = r % 32;
+
+                        sfeatures->features[block].valid |= 1 << bit;
+
+                        if (features[i])
+                                sfeatures->features[block].requested |= 1 << bit;
+                        else
+                                sfeatures->features[block].requested &= ~(1 << bit);
+                }
+        }
+
+        ifr.ifr_data = (void *) sfeatures;
+
+        r = ioctl(*fd, SIOCETHTOOL, &ifr);
+        if (r < 0)
+                return log_warning_errno(r, "link_config: could not set ethtool features for %s", ifname);
+
+        return 0;
+}
+
+static int get_glinksettings(int fd, struct ifreq *ifr, struct ethtool_link_usettings **g) {
+        struct ecmd {
+                struct ethtool_link_settings req;
+                __u32 link_mode_data[3 * ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32];
+        } ecmd = {
+                .req.cmd = ETHTOOL_GLINKSETTINGS,
+        };
+        struct ethtool_link_usettings *u;
+        unsigned offset;
+        int r;
+
+        /* The interaction user/kernel via the new API requires a small ETHTOOL_GLINKSETTINGS
+           handshake first to agree on the length of the link mode bitmaps. If kernel doesn't
+           agree with user, it returns the bitmap length it is expecting from user as a negative
+           length (and cmd field is 0). When kernel and user agree, kernel returns valid info in
+           all fields (ie. link mode length > 0 and cmd is ETHTOOL_GLINKSETTINGS). Based on
+           https://github.com/torvalds/linux/commit/3f1ac7a700d039c61d8d8b99f28d605d489a60cf
+        */
+
+        ifr->ifr_data = (void *) &ecmd;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        if (ecmd.req.link_mode_masks_nwords >= 0 || ecmd.req.cmd != ETHTOOL_GLINKSETTINGS)
+                return -EOPNOTSUPP;
+
+        ecmd.req.link_mode_masks_nwords = -ecmd.req.link_mode_masks_nwords;
+
+        ifr->ifr_data = (void *) &ecmd;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        if (ecmd.req.link_mode_masks_nwords <= 0 || ecmd.req.cmd != ETHTOOL_GLINKSETTINGS)
+                return -EOPNOTSUPP;
+
+        u = new0(struct ethtool_link_usettings , 1);
+        if (!u)
+                return -ENOMEM;
+
+        u->base = ecmd.req;
+
+        offset = 0;
+        memcpy(u->link_modes.supported, &ecmd.link_mode_data[offset], 4 * ecmd.req.link_mode_masks_nwords);
+
+        offset += ecmd.req.link_mode_masks_nwords;
+        memcpy(u->link_modes.advertising, &ecmd.link_mode_data[offset], 4 * ecmd.req.link_mode_masks_nwords);
+
+        offset += ecmd.req.link_mode_masks_nwords;
+        memcpy(u->link_modes.lp_advertising, &ecmd.link_mode_data[offset], 4 * ecmd.req.link_mode_masks_nwords);
+
+        *g = u;
+
+        return 0;
+}
+
+static int get_gset(int fd, struct ifreq *ifr, struct ethtool_link_usettings **u) {
+        struct ethtool_link_usettings *e;
+        struct ethtool_cmd ecmd = {
+                .cmd = ETHTOOL_GSET,
+        };
+        int r;
+
+        ifr->ifr_data = (void *) &ecmd;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        e = new0(struct ethtool_link_usettings, 1);
+        if (!e)
+                return -ENOMEM;
+
+        e->base.cmd = ETHTOOL_GSET;
+
+        e->base.link_mode_masks_nwords = 1;
+        e->base.speed = ethtool_cmd_speed(&ecmd);
+        e->base.duplex = ecmd.duplex;
+        e->base.port = ecmd.port;
+        e->base.phy_address = ecmd.phy_address;
+        e->base.autoneg = ecmd.autoneg;
+        e->base.mdio_support = ecmd.mdio_support;
+
+        e->link_modes.supported[0] = ecmd.supported;
+        e->link_modes.advertising[0] = ecmd.advertising;
+        e->link_modes.lp_advertising[0] = ecmd.lp_advertising;
+
+        *u = e;
+
+        return 0;
+}
+
+static int set_slinksettings(int fd, struct ifreq *ifr, const struct ethtool_link_usettings *u) {
+        struct {
+                struct ethtool_link_settings req;
+                __u32 link_mode_data[3 * ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32];
+        } ecmd = {};
+        unsigned offset;
+        int r;
+
+        if (u->base.cmd != ETHTOOL_GLINKSETTINGS || u->base.link_mode_masks_nwords <= 0)
+                return -EINVAL;
+
+        ecmd.req = u->base;
+        ecmd.req.cmd = ETHTOOL_SLINKSETTINGS;
+        offset = 0;
+        memcpy(&ecmd.link_mode_data[offset], u->link_modes.supported, 4 * ecmd.req.link_mode_masks_nwords);
+
+        offset += ecmd.req.link_mode_masks_nwords;
+        memcpy(&ecmd.link_mode_data[offset], u->link_modes.advertising, 4 * ecmd.req.link_mode_masks_nwords);
+
+        offset += ecmd.req.link_mode_masks_nwords;
+        memcpy(&ecmd.link_mode_data[offset], u->link_modes.lp_advertising, 4 * ecmd.req.link_mode_masks_nwords);
+
+        ifr->ifr_data = (void *) &ecmd;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int set_sset(int fd, struct ifreq *ifr, const struct ethtool_link_usettings *u) {
+        struct ethtool_cmd ecmd = {
+                .cmd = ETHTOOL_SSET,
+        };
+        int r;
+
+        if (u->base.cmd != ETHTOOL_GSET || u->base.link_mode_masks_nwords <= 0)
+                return -EINVAL;
+
+        ecmd.supported = u->link_modes.supported[0];
+        ecmd.advertising = u->link_modes.advertising[0];
+        ecmd.lp_advertising = u->link_modes.lp_advertising[0];
+
+        ethtool_cmd_speed_set(&ecmd, u->base.speed);
+
+        ecmd.duplex = u->base.duplex;
+        ecmd.port = u->base.port;
+        ecmd.phy_address = u->base.phy_address;
+        ecmd.autoneg = u->base.autoneg;
+        ecmd.mdio_support = u->base.mdio_support;
+        ecmd.eth_tp_mdix = u->base.eth_tp_mdix;
+        ecmd.eth_tp_mdix_ctrl = u->base.eth_tp_mdix_ctrl;
+
+        ifr->ifr_data = (void *) &ecmd;
+
+        r = ioctl(fd, SIOCETHTOOL, ifr);
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+/* If autonegotiation is disabled, the speed and duplex represent the fixed link
+ * mode and are writable if the driver supports multiple link modes. If it is
+ * enabled then they are read-only. If the link is up they represent the negotiated
+ * link mode; if the link is down, the speed is 0, %SPEED_UNKNOWN or the highest
+ * enabled speed and @duplex is %DUPLEX_UNKNOWN or the best enabled duplex mode.
+ */
+int ethtool_set_glinksettings(int *fd, const char *ifname, struct link_config *link) {
+        _cleanup_free_ struct ethtool_link_usettings *u = NULL;
+        struct ifreq ifr = {};
+        int r;
+
+        if (link->autonegotiation != AUTONEG_DISABLE && eqzero(link->advertise)) {
+                log_info("link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.");
+                return 0;
+        }
+
+        if (*fd < 0) {
+                r = ethtool_connect(fd);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: could not connect to ethtool: %m");
+        }
+
+        strscpy(ifr.ifr_name, IFNAMSIZ, ifname);
+
+        r = get_glinksettings(*fd, &ifr, &u);
+        if (r < 0) {
+                r = get_gset(*fd, &ifr, &u);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: Cannot get device settings for %s : %m", ifname);
+        }
+
+        if (link->speed)
+                u->base.speed = DIV_ROUND_UP(link->speed, 1000000);
+
+        if (link->duplex != _DUP_INVALID)
+                u->base.duplex = link->duplex;
+
+        if (link->port != _NET_DEV_PORT_INVALID)
+                u->base.port = link->port;
+
+        if (link->autonegotiation >= 0)
+                u->base.autoneg = link->autonegotiation;
+
+        if (!eqzero(link->advertise)) {
+                u->base.autoneg = AUTONEG_ENABLE;
+                memcpy(&u->link_modes.advertising, link->advertise, sizeof(link->advertise));
+                memzero((uint8_t*) &u->link_modes.advertising + sizeof(link->advertise),
+                        ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NBYTES - sizeof(link->advertise));
+        }
+
+        if (u->base.cmd == ETHTOOL_GLINKSETTINGS)
+                r = set_slinksettings(*fd, &ifr, u);
+        else
+                r = set_sset(*fd, &ifr, u);
+        if (r < 0)
+                return log_warning_errno(r, "link_config: Cannot set device settings for %s : %m", ifname);
+
+        return r;
+}
+
+int config_parse_channel(const char *unit,
+                         const char *filename,
+                         unsigned line,
+                         const char *section,
+                         unsigned section_line,
+                         const char *lvalue,
+                         int ltype,
+                         const char *rvalue,
+                         void *data,
+                         void *userdata) {
+        link_config *config = data;
+        uint32_t k;
+        int r;
+
+        assert(filename);
+        assert(section);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        r = safe_atou32(rvalue, &k);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse channel value, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        if (k < 1) {
+                log_syntax(unit, LOG_ERR, filename, line, -EINVAL, "Invalid %s value, ignoring: %s", lvalue, rvalue);
+                return 0;
+        }
+
+        if (streq(lvalue, "RxChannels")) {
+                config->channels.rx_count = k;
+                config->channels.rx_count_set = true;
+        } else if (streq(lvalue, "TxChannels")) {
+                config->channels.tx_count = k;
+                config->channels.tx_count_set = true;
+        } else if (streq(lvalue, "OtherChannels")) {
+                config->channels.other_count = k;
+                config->channels.other_count_set = true;
+        } else if (streq(lvalue, "CombinedChannels")) {
+                config->channels.combined_count = k;
+                config->channels.combined_count_set = true;
+        }
+
+        return 0;
+}
+
+int ethtool_set_channels(int *fd, const char *ifname, netdev_channels *channels) {
+        struct ethtool_channels ecmd = {
+                .cmd = ETHTOOL_GCHANNELS
+        };
+        struct ifreq ifr = {
+                .ifr_data = (void*) &ecmd
+        };
+
+        bool need_update = false;
+        int r;
+
+        if (*fd < 0) {
+                r = ethtool_connect(fd);
+                if (r < 0)
+                        return log_warning_errno(r, "link_config: could not connect to ethtool: %m");
+        }
+
+        strscpy(ifr.ifr_name, IFNAMSIZ, ifname);
+
+        r = ioctl(*fd, SIOCETHTOOL, &ifr);
+        if (r < 0)
+                return -errno;
+
+        if (channels->rx_count_set && ecmd.rx_count != channels->rx_count) {
+                ecmd.rx_count = channels->rx_count;
+                need_update = true;
+        }
+
+        if (channels->tx_count_set && ecmd.tx_count != channels->tx_count) {
+                ecmd.tx_count = channels->tx_count;
+                need_update = true;
+        }
+
+        if (channels->other_count_set && ecmd.other_count != channels->other_count) {
+                ecmd.other_count = channels->other_count;
+                need_update = true;
+        }
+
+        if (channels->combined_count_set && ecmd.combined_count != channels->combined_count) {
+                ecmd.combined_count = channels->combined_count;
+                need_update = true;
+        }
+
+        if (need_update) {
+                ecmd.cmd = ETHTOOL_SCHANNELS;
+
+                r = ioctl(*fd, SIOCETHTOOL, &ifr);
+                if (r < 0)
+                        return -errno;
+        }
+
+        return 0;
+}
+
+int config_parse_advertise(const char *unit,
+                           const char *filename,
+                           unsigned line,
+                           const char *section,
+                           unsigned section_line,
+                           const char *lvalue,
+                           int ltype,
+                           const char *rvalue,
+                           void *data,
+                           void *userdata) {
+        link_config *config = data;
+        const char *p;
+        int r;
+
+        assert(filename);
+        assert(section);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                /* Empty string resets the value. */
+                zero(config->advertise);
+                return 0;
+        }
+
+        for (p = rvalue;;) {
+                _cleanup_free_ char *w = NULL;
+                enum ethtool_link_mode_bit_indices mode;
+
+                r = extract_first_word(&p, &w, NULL, 0);
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to split advertise modes '%s', ignoring: %m", rvalue);
+                        break;
+                }
+                if (r == 0)
+                        break;
+
+                mode = ethtool_link_mode_bit_from_string(w);
+                if (mode < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0, "Failed to parse advertise mode, ignoring: %s", w);
+                        continue;
+                }
+
+                config->advertise[mode / 32] |= 1UL << (mode % 32);
+        }
+
+        return 0;
+}
diff --git a/src/udev/net/ethtool-util.h b/src/udev/net/ethtool-util.h
new file mode 100644
index 0000000..618b26b
--- /dev/null
+++ b/src/udev/net/ethtool-util.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <macro.h>
+#include <linux/ethtool.h>
+
+#include "conf-parser.h"
+#include "missing_network.h"
+
+struct link_config;
+
+/* we can't use DUPLEX_ prefix, as it
+ * clashes with <linux/ethtool.h> */
+typedef enum Duplex {
+        DUP_HALF = DUPLEX_HALF,
+        DUP_FULL = DUPLEX_FULL,
+        _DUP_MAX,
+        _DUP_INVALID = -1
+} Duplex;
+
+typedef enum WakeOnLan {
+        WOL_PHY,
+        WOL_UCAST,
+        WOL_MCAST,
+        WOL_BCAST,
+        WOL_ARP,
+        WOL_MAGIC,
+        WOL_MAGICSECURE,
+        WOL_OFF,
+        _WOL_MAX,
+        _WOL_INVALID = -1
+} WakeOnLan;
+
+typedef enum NetDevFeature {
+        NET_DEV_FEAT_GSO,
+        NET_DEV_FEAT_GRO,
+        NET_DEV_FEAT_LRO,
+        NET_DEV_FEAT_TSO,
+        NET_DEV_FEAT_TSO6,
+        _NET_DEV_FEAT_MAX,
+        _NET_DEV_FEAT_INVALID = -1
+} NetDevFeature;
+
+typedef enum NetDevPort {
+        NET_DEV_PORT_TP     = PORT_TP,
+        NET_DEV_PORT_AUI    = PORT_AUI,
+        NET_DEV_PORT_MII    = PORT_MII,
+        NET_DEV_PORT_FIBRE  = PORT_FIBRE,
+        NET_DEV_PORT_BNC    = PORT_BNC,
+        NET_DEV_PORT_DA     = PORT_DA,
+        NET_DEV_PORT_NONE   = PORT_NONE,
+        NET_DEV_PORT_OTHER  = PORT_OTHER,
+        _NET_DEV_PORT_MAX,
+        _NET_DEV_PORT_INVALID = -1
+} NetDevPort;
+
+#define ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32    (SCHAR_MAX)
+#define ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NBYTES  (4 * ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32)
+
+/* layout of the struct passed from/to userland */
+struct ethtool_link_usettings {
+        struct ethtool_link_settings base;
+
+        struct {
+                uint32_t supported[ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32];
+                uint32_t advertising[ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32];
+                uint32_t lp_advertising[ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32];
+        } link_modes;
+};
+
+typedef struct netdev_channels {
+        uint32_t rx_count;
+        uint32_t tx_count;
+        uint32_t other_count;
+        uint32_t combined_count;
+
+        bool rx_count_set;
+        bool tx_count_set;
+        bool other_count_set;
+        bool combined_count_set;
+} netdev_channels;
+
+int ethtool_connect(int *ret);
+
+int ethtool_get_driver(int *fd, const char *ifname, char **ret);
+int ethtool_set_speed(int *fd, const char *ifname, unsigned speed, Duplex duplex);
+int ethtool_set_wol(int *fd, const char *ifname, WakeOnLan wol);
+int ethtool_set_features(int *fd, const char *ifname, int *features);
+int ethtool_set_glinksettings(int *fd, const char *ifname, struct link_config *link);
+int ethtool_set_channels(int *fd, const char *ifname, netdev_channels *channels);
+
+const char *duplex_to_string(Duplex d) _const_;
+Duplex duplex_from_string(const char *d) _pure_;
+
+const char *wol_to_string(WakeOnLan wol) _const_;
+WakeOnLan wol_from_string(const char *wol) _pure_;
+
+const char *port_to_string(NetDevPort port) _const_;
+NetDevPort port_from_string(const char *port) _pure_;
+
+const char *ethtool_link_mode_bit_to_string(enum ethtool_link_mode_bit_indices val) _const_;
+enum ethtool_link_mode_bit_indices ethtool_link_mode_bit_from_string(const char *str) _pure_;
+
+CONFIG_PARSER_PROTOTYPE(config_parse_duplex);
+CONFIG_PARSER_PROTOTYPE(config_parse_wol);
+CONFIG_PARSER_PROTOTYPE(config_parse_port);
+CONFIG_PARSER_PROTOTYPE(config_parse_channel);
+CONFIG_PARSER_PROTOTYPE(config_parse_advertise);
diff --git a/src/udev/net/link-config-gperf.gperf b/src/udev/net/link-config-gperf.gperf
new file mode 100644
index 0000000..2bc18bf
--- /dev/null
+++ b/src/udev/net/link-config-gperf.gperf
@@ -0,0 +1,54 @@
+%{
+#if __GNUC__ >= 7
+_Pragma("GCC diagnostic ignored \"-Wimplicit-fallthrough\"")
+#endif
+#include <stddef.h>
+#include "conf-parser.h"
+#include "ethtool-util.h"
+#include "link-config.h"
+#include "network-internal.h"
+%}
+struct ConfigPerfItem;
+%null_strings
+%language=ANSI-C
+%define slot-name section_and_lvalue
+%define hash-function-name link_config_gperf_hash
+%define lookup-function-name link_config_gperf_lookup
+%readonly-tables
+%omit-struct-type
+%struct-type
+%includes
+%%
+Match.MACAddress,                config_parse_hwaddrs,       0,                             offsetof(link_config, match_mac)
+Match.OriginalName,              config_parse_ifnames,       0,                             offsetof(link_config, match_name)
+Match.Path,                      config_parse_strv,          0,                             offsetof(link_config, match_path)
+Match.Driver,                    config_parse_strv,          0,                             offsetof(link_config, match_driver)
+Match.Type,                      config_parse_strv,          0,                             offsetof(link_config, match_type)
+Match.Host,                      config_parse_net_condition, CONDITION_HOST,                offsetof(link_config, match_host)
+Match.Virtualization,            config_parse_net_condition, CONDITION_VIRTUALIZATION,      offsetof(link_config, match_virt)
+Match.KernelCommandLine,         config_parse_net_condition, CONDITION_KERNEL_COMMAND_LINE, offsetof(link_config, match_kernel_cmdline)
+Match.KernelVersion,             config_parse_net_condition, CONDITION_KERNEL_VERSION,      offsetof(link_config, match_kernel_version)
+Match.Architecture,              config_parse_net_condition, CONDITION_ARCHITECTURE,        offsetof(link_config, match_arch)
+Link.Description,                config_parse_string,        0,                             offsetof(link_config, description)
+Link.MACAddressPolicy,           config_parse_mac_policy,    0,                             offsetof(link_config, mac_policy)
+Link.MACAddress,                 config_parse_hwaddr,        0,                             offsetof(link_config, mac)
+Link.NamePolicy,                 config_parse_name_policy,   0,                             offsetof(link_config, name_policy)
+Link.Name,                       config_parse_ifname,        0,                             offsetof(link_config, name)
+Link.Alias,                      config_parse_ifalias,       0,                             offsetof(link_config, alias)
+Link.MTUBytes,                   config_parse_mtu,           AF_UNSPEC,                     offsetof(link_config, mtu)
+Link.BitsPerSecond,              config_parse_si_size,       0,                             offsetof(link_config, speed)
+Link.Duplex,                     config_parse_duplex,        0,                             offsetof(link_config, duplex)
+Link.AutoNegotiation,            config_parse_tristate,      0,                             offsetof(link_config, autonegotiation)
+Link.WakeOnLan,                  config_parse_wol,           0,                             offsetof(link_config, wol)
+Link.Port,                       config_parse_port,          0,                             offsetof(link_config, port)
+Link.GenericSegmentationOffload, config_parse_tristate,      0,                             offsetof(link_config, features[NET_DEV_FEAT_GSO])
+Link.TCPSegmentationOffload,     config_parse_tristate,      0,                             offsetof(link_config, features[NET_DEV_FEAT_TSO])
+Link.TCP6SegmentationOffload,    config_parse_tristate,      0,                             offsetof(link_config, features[NET_DEV_FEAT_TSO6])
+Link.UDPSegmentationOffload,     config_parse_warn_compat,   DISABLED_LEGACY,               0
+Link.GenericReceiveOffload,      config_parse_tristate,      0,                             offsetof(link_config, features[NET_DEV_FEAT_GRO])
+Link.LargeReceiveOffload,        config_parse_tristate,      0,                             offsetof(link_config, features[NET_DEV_FEAT_LRO])
+Link.RxChannels,                 config_parse_channel,       0,                             0
+Link.TxChannels,                 config_parse_channel,       0,                             0
+Link.OtherChannels,              config_parse_channel,       0,                             0
+Link.CombinedChannels,           config_parse_channel,       0,                             0
+Link.Advertise,                  config_parse_advertise,     0,                             0
diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c
new file mode 100644
index 0000000..eb2477c
--- /dev/null
+++ b/src/udev/net/link-config.c
@@ -0,0 +1,535 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <netinet/ether.h>
+
+#include "sd-device.h"
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "conf-files.h"
+#include "conf-parser.h"
+#include "device-util.h"
+#include "ethtool-util.h"
+#include "fd-util.h"
+#include "link-config.h"
+#include "log.h"
+#include "missing_network.h"
+#include "naming-scheme.h"
+#include "netlink-util.h"
+#include "network-internal.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "proc-cmdline.h"
+#include "random-util.h"
+#include "stat-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
+
+struct link_config_ctx {
+        LIST_HEAD(link_config, links);
+
+        int ethtool_fd;
+
+        bool enable_name_policy;
+
+        sd_netlink *rtnl;
+
+        usec_t link_dirs_ts_usec;
+};
+
+static const char* const link_dirs[] = {
+        "/etc/systemd/network",
+        "/run/systemd/network",
+        "/usr/lib/systemd/network",
+#if HAVE_SPLIT_USR
+        "/lib/systemd/network",
+#endif
+        NULL};
+
+static void link_config_free(link_config *link) {
+        if (!link)
+                return;
+
+        free(link->filename);
+
+        set_free_free(link->match_mac);
+        strv_free(link->match_path);
+        strv_free(link->match_driver);
+        strv_free(link->match_type);
+        free(link->match_name);
+        free(link->match_host);
+        free(link->match_virt);
+        free(link->match_kernel_cmdline);
+        free(link->match_kernel_version);
+        free(link->match_arch);
+
+        free(link->description);
+        free(link->mac);
+        free(link->name_policy);
+        free(link->name);
+        free(link->alias);
+
+        free(link);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(link_config*, link_config_free);
+
+static void link_configs_free(link_config_ctx *ctx) {
+        link_config *link, *link_next;
+
+        if (!ctx)
+                return;
+
+        LIST_FOREACH_SAFE(links, link, link_next, ctx->links)
+                link_config_free(link);
+}
+
+void link_config_ctx_free(link_config_ctx *ctx) {
+        if (!ctx)
+                return;
+
+        safe_close(ctx->ethtool_fd);
+
+        sd_netlink_unref(ctx->rtnl);
+
+        link_configs_free(ctx);
+
+        free(ctx);
+
+        return;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(link_config_ctx*, link_config_ctx_free);
+
+int link_config_ctx_new(link_config_ctx **ret) {
+        _cleanup_(link_config_ctx_freep) link_config_ctx *ctx = NULL;
+
+        if (!ret)
+                return -EINVAL;
+
+        ctx = new0(link_config_ctx, 1);
+        if (!ctx)
+                return -ENOMEM;
+
+        LIST_HEAD_INIT(ctx->links);
+
+        ctx->ethtool_fd = -1;
+
+        ctx->enable_name_policy = true;
+
+        *ret = TAKE_PTR(ctx);
+
+        return 0;
+}
+
+static int load_link(link_config_ctx *ctx, const char *filename) {
+        _cleanup_(link_config_freep) link_config *link = NULL;
+        _cleanup_fclose_ FILE *file = NULL;
+        int i;
+        int r;
+
+        assert(ctx);
+        assert(filename);
+
+        file = fopen(filename, "re");
+        if (!file) {
+                if (errno == ENOENT)
+                        return 0;
+                else
+                        return -errno;
+        }
+
+        if (null_or_empty_fd(fileno(file))) {
+                log_debug("Skipping empty file: %s", filename);
+                return 0;
+        }
+
+        link = new0(link_config, 1);
+        if (!link)
+                return log_oom();
+
+        link->mac_policy = _MACPOLICY_INVALID;
+        link->wol = _WOL_INVALID;
+        link->duplex = _DUP_INVALID;
+        link->port = _NET_DEV_PORT_INVALID;
+        link->autonegotiation = -1;
+
+        for (i = 0; i < (int)ELEMENTSOF(link->features); i++)
+                link->features[i] = -1;
+
+        r = config_parse(NULL, filename, file,
+                         "Match\0Link\0Ethernet\0",
+                         config_item_perf_lookup, link_config_gperf_lookup,
+                         CONFIG_PARSE_WARN, link);
+        if (r < 0)
+                return r;
+        else
+                log_debug("Parsed configuration file %s", filename);
+
+        if (link->speed > UINT_MAX)
+                return -ERANGE;
+
+        link->filename = strdup(filename);
+        if (!link->filename)
+                return log_oom();
+
+        LIST_PREPEND(links, ctx->links, link);
+        link = NULL;
+
+        return 0;
+}
+
+static bool enable_name_policy(void) {
+        bool b;
+
+        return proc_cmdline_get_bool("net.ifnames", &b) <= 0 || b;
+}
+
+static int link_name_type(sd_device *device, unsigned *type) {
+        const char *s;
+        int r;
+
+        r = sd_device_get_sysattr_value(device, "name_assign_type", &s);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "Failed to query name_assign_type: %m");
+
+        r = safe_atou(s, type);
+        if (r < 0)
+                return log_device_warning_errno(device, r, "Failed to parse name_assign_type \"%s\": %m", s);
+
+        log_device_debug(device, "Device has name_assign_type=%d", *type);
+        return 0;
+}
+
+int link_config_load(link_config_ctx *ctx) {
+        _cleanup_strv_free_ char **files;
+        char **f;
+        int r;
+
+        link_configs_free(ctx);
+
+        if (!enable_name_policy()) {
+                ctx->enable_name_policy = false;
+                log_info("Network interface NamePolicy= disabled on kernel command line, ignoring.");
+        }
+
+        /* update timestamp */
+        paths_check_timestamp(link_dirs, &ctx->link_dirs_ts_usec, true);
+
+        r = conf_files_list_strv(&files, ".link", NULL, 0, link_dirs);
+        if (r < 0)
+                return log_error_errno(r, "failed to enumerate link files: %m");
+
+        STRV_FOREACH_BACKWARDS(f, files) {
+                r = load_link(ctx, *f);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+bool link_config_should_reload(link_config_ctx *ctx) {
+        return paths_check_timestamp(link_dirs, &ctx->link_dirs_ts_usec, false);
+}
+
+int link_config_get(link_config_ctx *ctx, sd_device *device, link_config **ret) {
+        link_config *link;
+
+        assert(ctx);
+        assert(device);
+        assert(ret);
+
+        LIST_FOREACH(links, link, ctx->links) {
+                const char *address = NULL, *id_path = NULL, *parent_driver = NULL, *id_net_driver = NULL, *devtype = NULL, *sysname = NULL;
+                sd_device *parent;
+
+                (void) sd_device_get_sysattr_value(device, "address", &address);
+                (void) sd_device_get_property_value(device, "ID_PATH", &id_path);
+                if (sd_device_get_parent(device, &parent) >= 0)
+                        (void) sd_device_get_driver(parent, &parent_driver);
+                (void) sd_device_get_property_value(device, "ID_NET_DRIVER", &id_net_driver);
+                (void) sd_device_get_devtype(device, &devtype);
+                (void) sd_device_get_sysname(device, &sysname);
+
+                if (net_match_config(link->match_mac, link->match_path, link->match_driver,
+                                     link->match_type, link->match_name, link->match_host,
+                                     link->match_virt, link->match_kernel_cmdline,
+                                     link->match_kernel_version, link->match_arch,
+                                     address ? ether_aton(address) : NULL,
+                                     id_path,
+                                     parent_driver,
+                                     id_net_driver,
+                                     devtype,
+                                     sysname)) {
+                        if (link->match_name) {
+                                unsigned char name_assign_type = NET_NAME_UNKNOWN;
+                                const char *attr_value;
+
+                                if (sd_device_get_sysattr_value(device, "name_assign_type", &attr_value) >= 0)
+                                        (void) safe_atou8(attr_value, &name_assign_type);
+
+                                if (name_assign_type == NET_NAME_ENUM) {
+                                        log_warning("Config file %s applies to device based on potentially unpredictable interface name '%s'",
+                                                    link->filename, sysname);
+                                        *ret = link;
+
+                                        return 0;
+                                } else if (name_assign_type == NET_NAME_RENAMED) {
+                                        log_warning("Config file %s matches device based on renamed interface name '%s', ignoring",
+                                                    link->filename, sysname);
+
+                                        continue;
+                                }
+                        }
+
+                        log_debug("Config file %s applies to device %s",
+                                  link->filename, sysname);
+
+                        *ret = link;
+                        return 0;
+                }
+        }
+
+        *ret = NULL;
+        return -ENOENT;
+}
+
+static bool mac_is_random(sd_device *device) {
+        const char *s;
+        unsigned type;
+        int r;
+
+        /* if we can't get the assign type, assume it is not random */
+        if (sd_device_get_sysattr_value(device, "addr_assign_type", &s) < 0)
+                return false;
+
+        r = safe_atou(s, &type);
+        if (r < 0)
+                return false;
+
+        return type == NET_ADDR_RANDOM;
+}
+
+static int get_mac(sd_device *device, bool want_random,
+                   struct ether_addr *mac) {
+        int r;
+
+        if (want_random)
+                random_bytes(mac->ether_addr_octet, ETH_ALEN);
+        else {
+                uint64_t result;
+
+                r = net_get_unique_predictable_data(device, &result);
+                if (r < 0)
+                        return r;
+
+                assert_cc(ETH_ALEN <= sizeof(result));
+                memcpy(mac->ether_addr_octet, &result, ETH_ALEN);
+        }
+
+        /* see eth_random_addr in the kernel */
+        mac->ether_addr_octet[0] &= 0xfe;  /* clear multicast bit */
+        mac->ether_addr_octet[0] |= 0x02;  /* set local assignment bit (IEEE802) */
+
+        return 0;
+}
+
+int link_config_apply(link_config_ctx *ctx, link_config *config,
+                      sd_device *device, const char **name) {
+        struct ether_addr generated_mac;
+        struct ether_addr *mac = NULL;
+        const char *new_name = NULL;
+        const char *old_name;
+        unsigned speed, name_type = NET_NAME_UNKNOWN;
+        NamePolicy policy;
+        int r, ifindex;
+
+        assert(ctx);
+        assert(config);
+        assert(device);
+        assert(name);
+
+        r = sd_device_get_sysname(device, &old_name);
+        if (r < 0)
+                return r;
+
+        r = ethtool_set_glinksettings(&ctx->ethtool_fd, old_name, config);
+        if (r < 0) {
+
+                if (config->port != _NET_DEV_PORT_INVALID)
+                        log_warning_errno(r, "Could not set port (%s) of %s: %m", port_to_string(config->port), old_name);
+
+                if (!eqzero(config->advertise))
+                        log_warning_errno(r, "Could not set advertise mode: %m"); /* TODO: include modes in the log message. */
+
+                if (config->speed) {
+                        speed = DIV_ROUND_UP(config->speed, 1000000);
+                        if (r == -EOPNOTSUPP) {
+                                r = ethtool_set_speed(&ctx->ethtool_fd, old_name, speed, config->duplex);
+                                if (r < 0)
+                                        log_warning_errno(r, "Could not set speed of %s to %u Mbps: %m", old_name, speed);
+                        }
+                }
+
+                if (config->duplex !=_DUP_INVALID)
+                        log_warning_errno(r, "Could not set duplex of %s to (%s): %m", old_name, duplex_to_string(config->duplex));
+        }
+
+        r = ethtool_set_wol(&ctx->ethtool_fd, old_name, config->wol);
+        if (r < 0)
+                log_warning_errno(r, "Could not set WakeOnLan of %s to %s: %m",
+                                  old_name, wol_to_string(config->wol));
+
+        r = ethtool_set_features(&ctx->ethtool_fd, old_name, config->features);
+        if (r < 0)
+                log_warning_errno(r, "Could not set offload features of %s: %m", old_name);
+
+        if (config->channels.rx_count_set || config->channels.tx_count_set || config->channels.other_count_set || config->channels.combined_count_set) {
+                r = ethtool_set_channels(&ctx->ethtool_fd, old_name, &config->channels);
+                if (r < 0)
+                        log_warning_errno(r, "Could not set channels of %s: %m", old_name);
+        }
+
+        r = sd_device_get_ifindex(device, &ifindex);
+        if (r < 0)
+                return log_device_warning_errno(device, r, "Could not find ifindex: %m");
+
+
+        (void) link_name_type(device, &name_type);
+
+        if (IN_SET(name_type, NET_NAME_USER, NET_NAME_RENAMED)
+            && !naming_scheme_has(NAMING_ALLOW_RERENAMES)) {
+                log_device_debug(device, "Device already has a name given by userspace, not renaming.");
+                goto no_rename;
+        }
+
+        if (ctx->enable_name_policy && config->name_policy)
+                for (NamePolicy *p = config->name_policy; !new_name && *p != _NAMEPOLICY_INVALID; p++) {
+                        policy = *p;
+
+                        switch (policy) {
+                        case NAMEPOLICY_KERNEL:
+                                if (name_type != NET_NAME_PREDICTABLE)
+                                        continue;
+
+                                /* The kernel claims to have given a predictable name, keep it. */
+                                log_device_debug(device, "Policy *%s*: keeping predictable kernel name",
+                                                 name_policy_to_string(policy));
+                                goto no_rename;
+                        case NAMEPOLICY_KEEP:
+                                if (!IN_SET(name_type, NET_NAME_USER, NET_NAME_RENAMED))
+                                        continue;
+
+                                log_device_debug(device, "Policy *%s*: keeping existing userspace name",
+                                                 name_policy_to_string(policy));
+                                goto no_rename;
+                        case NAMEPOLICY_DATABASE:
+                                (void) sd_device_get_property_value(device, "ID_NET_NAME_FROM_DATABASE", &new_name);
+                                break;
+                        case NAMEPOLICY_ONBOARD:
+                                (void) sd_device_get_property_value(device, "ID_NET_NAME_ONBOARD", &new_name);
+                                break;
+                        case NAMEPOLICY_SLOT:
+                                (void) sd_device_get_property_value(device, "ID_NET_NAME_SLOT", &new_name);
+                                break;
+                        case NAMEPOLICY_PATH:
+                                (void) sd_device_get_property_value(device, "ID_NET_NAME_PATH", &new_name);
+                                break;
+                        case NAMEPOLICY_MAC:
+                                (void) sd_device_get_property_value(device, "ID_NET_NAME_MAC", &new_name);
+                                break;
+                        default:
+                                assert_not_reached("invalid policy");
+                        }
+                }
+
+        if (new_name)
+                log_device_debug(device, "Policy *%s* yields \"%s\".", name_policy_to_string(policy), new_name);
+        else if (config->name) {
+                new_name = config->name;
+                log_device_debug(device, "Policies didn't yield a name, using specified Name=%s.", new_name);
+        } else
+                log_device_debug(device, "Policies didn't yield a name and Name= is not given, not renaming.");
+ no_rename:
+
+        switch (config->mac_policy) {
+                case MACPOLICY_PERSISTENT:
+                        if (mac_is_random(device)) {
+                                r = get_mac(device, false, &generated_mac);
+                                if (r == -ENOENT) {
+                                        log_warning_errno(r, "Could not generate persistent MAC address for %s: %m", old_name);
+                                        break;
+                                } else if (r < 0)
+                                        return r;
+                                mac = &generated_mac;
+                        }
+                        break;
+                case MACPOLICY_RANDOM:
+                        if (!mac_is_random(device)) {
+                                r = get_mac(device, true, &generated_mac);
+                                if (r == -ENOENT) {
+                                        log_warning_errno(r, "Could not generate random MAC address for %s: %m", old_name);
+                                        break;
+                                } else if (r < 0)
+                                        return r;
+                                mac = &generated_mac;
+                        }
+                        break;
+                case MACPOLICY_NONE:
+                default:
+                        mac = config->mac;
+        }
+
+        r = rtnl_set_link_properties(&ctx->rtnl, ifindex, config->alias, mac, config->mtu);
+        if (r < 0)
+                return log_warning_errno(r, "Could not set Alias=, MACAddress= or MTU= on %s: %m", old_name);
+
+        *name = new_name;
+
+        return 0;
+}
+
+int link_get_driver(link_config_ctx *ctx, sd_device *device, char **ret) {
+        const char *name;
+        char *driver = NULL;
+        int r;
+
+        r = sd_device_get_sysname(device, &name);
+        if (r < 0)
+                return r;
+
+        r = ethtool_get_driver(&ctx->ethtool_fd, name, &driver);
+        if (r < 0)
+                return r;
+
+        *ret = driver;
+        return 0;
+}
+
+static const char* const mac_policy_table[_MACPOLICY_MAX] = {
+        [MACPOLICY_PERSISTENT] = "persistent",
+        [MACPOLICY_RANDOM] = "random",
+        [MACPOLICY_NONE] = "none",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(mac_policy, MACPolicy);
+DEFINE_CONFIG_PARSE_ENUM(config_parse_mac_policy, mac_policy, MACPolicy,
+                         "Failed to parse MAC address policy");
+
+static const char* const name_policy_table[_NAMEPOLICY_MAX] = {
+        [NAMEPOLICY_KERNEL] = "kernel",
+        [NAMEPOLICY_KEEP] = "keep",
+        [NAMEPOLICY_DATABASE] = "database",
+        [NAMEPOLICY_ONBOARD] = "onboard",
+        [NAMEPOLICY_SLOT] = "slot",
+        [NAMEPOLICY_PATH] = "path",
+        [NAMEPOLICY_MAC] = "mac",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(name_policy, NamePolicy);
+DEFINE_CONFIG_PARSE_ENUMV(config_parse_name_policy, name_policy, NamePolicy,
+                          _NAMEPOLICY_INVALID,
+                          "Failed to parse interface name policy");
diff --git a/src/udev/net/link-config.h b/src/udev/net/link-config.h
new file mode 100644
index 0000000..1113b10
--- /dev/null
+++ b/src/udev/net/link-config.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include "sd-device.h"
+
+#include "condition.h"
+#include "conf-parser.h"
+#include "ethtool-util.h"
+#include "list.h"
+#include "set.h"
+
+typedef struct link_config_ctx link_config_ctx;
+typedef struct link_config link_config;
+
+typedef enum MACPolicy {
+        MACPOLICY_PERSISTENT,
+        MACPOLICY_RANDOM,
+        MACPOLICY_NONE,
+        _MACPOLICY_MAX,
+        _MACPOLICY_INVALID = -1
+} MACPolicy;
+
+typedef enum NamePolicy {
+        NAMEPOLICY_KERNEL,
+        NAMEPOLICY_KEEP,
+        NAMEPOLICY_DATABASE,
+        NAMEPOLICY_ONBOARD,
+        NAMEPOLICY_SLOT,
+        NAMEPOLICY_PATH,
+        NAMEPOLICY_MAC,
+        _NAMEPOLICY_MAX,
+        _NAMEPOLICY_INVALID = -1
+} NamePolicy;
+
+struct link_config {
+        char *filename;
+
+        Set *match_mac;
+        char **match_path;
+        char **match_driver;
+        char **match_type;
+        char **match_name;
+        Condition *match_host;
+        Condition *match_virt;
+        Condition *match_kernel_cmdline;
+        Condition *match_kernel_version;
+        Condition *match_arch;
+
+        char *description;
+        struct ether_addr *mac;
+        MACPolicy mac_policy;
+        NamePolicy *name_policy;
+        char *name;
+        char *alias;
+        uint32_t mtu;
+        size_t speed;
+        Duplex duplex;
+        int autonegotiation;
+        uint32_t advertise[2];
+        WakeOnLan wol;
+        NetDevPort port;
+        int features[_NET_DEV_FEAT_MAX];
+        netdev_channels channels;
+
+        LIST_FIELDS(link_config, links);
+};
+
+int link_config_ctx_new(link_config_ctx **ret);
+void link_config_ctx_free(link_config_ctx *ctx);
+
+int link_config_load(link_config_ctx *ctx);
+bool link_config_should_reload(link_config_ctx *ctx);
+
+int link_config_get(link_config_ctx *ctx, sd_device *device, struct link_config **ret);
+int link_config_apply(link_config_ctx *ctx, struct link_config *config, sd_device *device, const char **name);
+int link_get_driver(link_config_ctx *ctx, sd_device *device, char **ret);
+
+const char *name_policy_to_string(NamePolicy p) _const_;
+NamePolicy name_policy_from_string(const char *p) _pure_;
+
+const char *mac_policy_to_string(MACPolicy p) _const_;
+MACPolicy mac_policy_from_string(const char *p) _pure_;
+
+/* gperf lookup function */
+const struct ConfigPerfItem* link_config_gperf_lookup(const char *key, GPERF_LEN_TYPE length);
+
+CONFIG_PARSER_PROTOTYPE(config_parse_mac_policy);
+CONFIG_PARSER_PROTOTYPE(config_parse_name_policy);
diff --git a/src/udev/net/naming-scheme.c b/src/udev/net/naming-scheme.c
new file mode 100644
index 0000000..27cede5
--- /dev/null
+++ b/src/udev/net/naming-scheme.c
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#include "alloc-util.h"
+#include "naming-scheme.h"
+#include "proc-cmdline.h"
+#include "string-util.h"
+
+static const NamingScheme naming_schemes[] = {
+        { "v238", NAMING_V238 },
+        { "v239", NAMING_V239 },
+        { "v240", NAMING_V240 },
+        /* … add more schemes here, as the logic to name devices is updated … */
+};
+
+static const NamingScheme* naming_scheme_from_name(const char *name) {
+        size_t i;
+
+        if (streq(name, "latest"))
+                return naming_schemes + ELEMENTSOF(naming_schemes) - 1;
+
+        for (i = 0; i < ELEMENTSOF(naming_schemes); i++)
+                if (streq(naming_schemes[i].name, name))
+                        return naming_schemes + i;
+
+        return NULL;
+}
+
+const NamingScheme* naming_scheme(void) {
+        static const NamingScheme *cache = NULL;
+        _cleanup_free_ char *buffer = NULL;
+        const char *e, *k;
+
+        if (cache)
+                return cache;
+
+        /* Acquire setting from the kernel command line */
+        (void) proc_cmdline_get_key("net.naming-scheme", 0, &buffer);
+
+        /* Also acquire it from an env var */
+        e = getenv("NET_NAMING_SCHEME");
+        if (e) {
+                if (*e == ':') {
+                        /* If prefixed with ':' the kernel cmdline takes precedence */
+                        k = buffer ?: e + 1;
+                } else
+                        k = e; /* Otherwise the env var takes precedence */
+        } else
+                k = buffer;
+
+        if (k) {
+                cache = naming_scheme_from_name(k);
+                if (cache) {
+                        log_info("Using interface naming scheme '%s'.", cache->name);
+                        return cache;
+                }
+
+                log_warning("Unknown interface naming scheme '%s' requested, ignoring.", k);
+        }
+
+        cache = naming_scheme_from_name(DEFAULT_NET_NAMING_SCHEME);
+        assert(cache);
+        log_info("Using default interface naming scheme '%s'.", cache->name);
+
+        return cache;
+}
diff --git a/src/udev/net/naming-scheme.h b/src/udev/net/naming-scheme.h
new file mode 100644
index 0000000..0b3d9bf
--- /dev/null
+++ b/src/udev/net/naming-scheme.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <stdbool.h>
+
+#include "macro.h"
+
+/* So here's the deal: net_id is supposed to be an excercise in providing stable names for network devices. However, we
+ * also want to keep updating the naming scheme used in future versions of net_id. These two goals of course are
+ * contradictory: on one hand we want things to not change and on the other hand we want them to improve. Our way out
+ * of this dilemma is to introduce the "naming scheme" concept: each time we improve the naming logic we define a new
+ * flag for it. Then, we keep a list of schemes, each identified by a name associated with the flags it implements. Via
+ * a kernel command line and environment variable we then allow the user to pick the scheme they want us to follow:
+ * installers could "freeze" the used scheme at the moment of installation this way.
+ *
+ * Developers: each time you tweak the naming logic here, define a new flag below, and condition the tweak with
+ * it. Each time we do a release we'll then add a new scheme entry and include all newly defined flags.
+ *
+ * Note that this is only half a solution to the problem though: not only udev/net_id gets updated all the time, the
+ * kernel gets too. And thus a kernel that previously didn't expose some sysfs attribute we look for might eventually
+ * do, and thus affect our naming scheme too. Thus, enforcing a naming scheme will make interfacing more stable across
+ * OS versions, but not fully stabilize them. */
+typedef enum NamingSchemeFlags {
+        /* First, the individual features */
+        NAMING_SR_IOV_V        = 1 << 0, /* Use "v" suffix for SR-IOV, see 609948c7043a40008b8299529c978ed8e11de8f6*/
+        NAMING_NPAR_ARI        = 1 << 1, /* Use NPAR "ARI", see 6bc04997b6eab35d1cb9fa73889892702c27be09 */
+        NAMING_INFINIBAND      = 1 << 2, /* Use "ib" prefix for infiniband, see 938d30aa98df887797c9e05074a562ddacdcdf5e */
+        NAMING_ZERO_ACPI_INDEX = 1 << 3, /* Allow zero acpi_index field, see d81186ef4f6a888a70f20a1e73a812d6acb9e22f */
+        NAMING_ALLOW_RERENAMES = 1 << 4, /* Allow re-renaming of devices, see #9006 */
+
+        /* And now the masks that combine the features above */
+        NAMING_V238 = 0,
+        NAMING_V239 = NAMING_V238 | NAMING_SR_IOV_V | NAMING_NPAR_ARI,
+        NAMING_V240 = NAMING_V239 | NAMING_INFINIBAND | NAMING_ZERO_ACPI_INDEX | NAMING_ALLOW_RERENAMES,
+
+        _NAMING_SCHEME_FLAGS_INVALID = -1,
+} NamingSchemeFlags;
+
+typedef struct NamingScheme {
+        const char *name;
+        NamingSchemeFlags flags;
+} NamingScheme;
+
+const NamingScheme* naming_scheme(void);
+
+static inline bool naming_scheme_has(NamingSchemeFlags flags) {
+        return FLAGS_SET(naming_scheme()->flags, flags);
+}