netif-util: move several functions from network-util.[ch] to shared/netif-util.[ch]

These functions are not relevant to sd-network, and only used by
networkd, networkctl, and udevd.

src/shared/meson.build

@@ -218,6 +218,8 @@ shared_sources = files('''
         net-condition.h
         netif-naming-scheme.c
         netif-naming-scheme.h
+        netif-util.c
+        netif-util.h
         nscd-flush.h
         nsflags.c
         nsflags.h

src/shared/net-condition.c

@@ -6,6 +6,7 @@
 #include "env-util.h"
 #include "log.h"
 #include "net-condition.h"
+#include "netif-util.h"
 #include "network-util.h"
 #include "socket-util.h"
 #include "string-table.h"

src/shared/netif-util.c

@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-id128.h"
+
+#include "arphrd-util.h"
+#include "device-util.h"
+#include "netif-util.h"
+#include "siphash24.h"
+#include "sparse-endian.h"
+#include "strv.h"
+
+int link_get_type_string(sd_device *device, unsigned short iftype, char **ret) {
+        const char *t;
+        char *p;
+
+        if (device &&
+            sd_device_get_devtype(device, &t) >= 0 &&
+            !isempty(t)) {
+                p = strdup(t);
+                if (!p)
+                        return -ENOMEM;
+
+                *ret = p;
+                return 0;
+        }
+
+        t = arphrd_to_name(iftype);
+        if (!t)
+                return -ENOENT;
+
+        p = strdup(t);
+        if (!p)
+                return -ENOMEM;
+
+        *ret = ascii_strlower(p);
+        return 0;
+}
+
+const char *net_get_name_persistent(sd_device *device) {
+        const char *name, *field;
+
+        assert(device);
+
+        /* fetch some persistent data unique (on this machine) to this device */
+        FOREACH_STRING(field, "ID_NET_NAME_ONBOARD", "ID_NET_NAME_SLOT", "ID_NET_NAME_PATH", "ID_NET_NAME_MAC")
+                if (sd_device_get_property_value(device, field, &name) >= 0)
+                        return name;
+
+        return NULL;
+}
+
+#define HASH_KEY SD_ID128_MAKE(d3,1e,48,fa,90,fe,4b,4c,9d,af,d5,d7,a1,b1,2e,8a)
+
+int net_get_unique_predictable_data(sd_device *device, bool use_sysname, uint64_t *ret) {
+        size_t l, sz = 0;
+        const char *name;
+        int r;
+        uint8_t *v;
+
+        assert(device);
+
+        /* net_get_name_persistent() will return one of the device names based on stable information about
+         * the device. If this is not available, we fall back to using the actual device name. */
+        name = net_get_name_persistent(device);
+        if (!name && use_sysname)
+                (void) sd_device_get_sysname(device, &name);
+        if (!name)
+                return log_device_debug_errno(device, SYNTHETIC_ERRNO(ENODATA),
+                                              "No stable identifying information found");
+
+        log_device_debug(device, "Using \"%s\" as stable identifying information", name);
+        l = strlen(name);
+        sz = sizeof(sd_id128_t) + l;
+        v = newa(uint8_t, sz);
+
+        /* Fetch some persistent data unique to this machine */
+        r = sd_id128_get_machine((sd_id128_t*) v);
+        if (r < 0)
+                 return r;
+        memcpy(v + sizeof(sd_id128_t), name, l);
+
+        /* Let's hash the machine ID plus the device name. We use
+         * a fixed, but originally randomly created hash key here. */
+        *ret = htole64(siphash24(v, sz, HASH_KEY.bytes));
+        return 0;
+}

src/shared/netif-util.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+#include "sd-device.h"
+
+int link_get_type_string(sd_device *device, unsigned short iftype, char **ret);
+const char *net_get_name_persistent(sd_device *device);
+int net_get_unique_predictable_data(sd_device *device, bool use_sysname, uint64_t *ret);