udev: link-config - move naming policy from udev rules

This introduces a new key NamePolicy, which takes an ordered list of naming
policies. The first successful one is applide. If all fail the value of Name
(if any) is used.

The possible policies are 'onboard', 'slot', 'path' and 'mac'.

This patch introduces a default link file, which replaces the equivalent udev
rule.

7 files changed, 59 insertions, 19 deletions

diff --git a/Makefile.am b/Makefile.am
index e5ed3020b1..4a96a50057 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -83,7 +83,7 @@ userunitdir=$(prefix)/lib/systemd/user
 userpresetdir=$(prefix)/lib/systemd/user-preset
 tmpfilesdir=$(prefix)/lib/tmpfiles.d
 sysctldir=$(prefix)/lib/sysctl.d
-linkdir=$(prefix)/lib/net/links
+linksdir=$(prefix)/lib/net/links
 pkgincludedir=$(includedir)/systemd
 systemgeneratordir=$(rootlibexecdir)/system-generators
 usergeneratordir=$(prefix)/lib/systemd/user-generators
@@ -2214,6 +2214,9 @@ INSTALL_DIRS += \
 	$(sysconfdir)/udev/rules.d \
 	$(sysconfdir)/udev/hwdb.d
 
+dist_links_DATA = \
+	links/99-default.link
+
 dist_udevrules_DATA += \
 	rules/99-systemd.rules \
 	rules/42-usb-hid-pm.rules \
@@ -2228,7 +2231,6 @@ dist_udevrules_DATA += \
 	rules/75-net-description.rules \
 	rules/75-tty-description.rules \
 	rules/78-sound-card.rules \
-	rules/80-net-name-slot.rules \
 	rules/85-net-configure-link.rules \
 	rules/95-udev-late.rules
 
diff --git a/links/99-default.link b/links/99-default.link
new file mode 100644
index 0000000000..c5043b8570
--- /dev/null
+++ b/links/99-default.link
@@ -0,0 +1,2 @@
+[Link]
+NamePolicy=onboard slot path
diff --git a/rules/80-net-name-slot.rules b/rules/80-net-name-slot.rules
deleted file mode 100644
index c5f1b3885b..0000000000
--- a/rules/80-net-name-slot.rules
+++ /dev/null
@@ -1,14 +0,0 @@
-# do not edit this file, it will be overwritten on update
-
-ACTION!="add", GOTO="net_name_slot_end"
-SUBSYSTEM!="net", GOTO="net_name_slot_end"
-NAME!="", GOTO="net_name_slot_end"
-
-IMPORT{cmdline}="net.ifnames"
-ENV{net.ifnames}=="0", GOTO="net_name_slot_end"
-
-NAME=="", ENV{ID_NET_NAME_ONBOARD}!="", NAME="$env{ID_NET_NAME_ONBOARD}"
-NAME=="", ENV{ID_NET_NAME_SLOT}!="", NAME="$env{ID_NET_NAME_SLOT}"
-NAME=="", ENV{ID_NET_NAME_PATH}!="", NAME="$env{ID_NET_NAME_PATH}"
-
-LABEL="net_name_slot_end"
diff --git a/src/shared/util.c b/src/shared/util.c
index 2419a76d98..ef3b67b597 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -6004,7 +6004,7 @@ bool restore_state(void) {
         r = read_one_line_file("/proc/cmdline", &line);
         if (r < 0) {
                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
-                return 0;
+                return true; /* something is very wrong, let's not make it worse */
         }
 
         FOREACH_WORD_QUOTED(w, l, line, state)
diff --git a/src/udev/net/link-config-gperf.gperf b/src/udev/net/link-config-gperf.gperf
index 182a664192..b38dbe80bd 100644
--- a/src/udev/net/link-config-gperf.gperf
+++ b/src/udev/net/link-config-gperf.gperf
@@ -20,6 +20,7 @@ Match.Driver,                       config_parse_string,        0, offsetof(link
 Match.Type,                         config_parse_string,        0, offsetof(link_config, match_type)
 Link.Description,                   config_parse_string,        0, offsetof(link_config, description)
 Link.MACAddress,                    config_parse_string,        0, offsetof(link_config, mac)
+Link.NamePolicy,                    config_parse_strv,          0, offsetof(link_config, name_policy)
 Link.Name,                          config_parse_string,        0, offsetof(link_config, name)
 Link.MTU,                           config_parse_unsigned,      0, offsetof(link_config, mtu)
 Link.SpeedMBytes,                   config_parse_unsigned,      0, offsetof(link_config, speed)
diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c
index bb0640589b..9c75b62b73 100644
--- a/src/udev/net/link-config.c
+++ b/src/udev/net/link-config.c
@@ -34,6 +34,7 @@
 #include "path-util.h"
 #include "conf-parser.h"
 #include "conf-files.h"
+#include "fileio.h"
 
 struct link_config_ctx {
         LIST_HEAD(link_config, links);
@@ -308,8 +309,27 @@ static int rtnl_set_properties(sd_rtnl *rtnl, int ifindex, const char *name, con
         return 0;
 }
 
+static bool enable_name_policy(void) {
+        _cleanup_free_ char *line;
+        char *w, *state;
+        int r;
+        size_t l;
+
+        r = read_one_line_file("/proc/cmdline", &line);
+        if (r < 0) {
+                log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
+                return true; /* something is very wrong, let's not make it worse */
+        }
+
+        FOREACH_WORD_QUOTED(w, l, line, state)
+                if (strneq(w, "net.ifnames=0", l))
+                        return false;
+
+        return true;
+}
+
 int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_device *device) {
-        const char *name;
+        const char *name, *new_name = NULL;
         int r, ifindex;
 
         name = udev_device_get_sysname(device);
@@ -355,7 +375,35 @@ int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_dev
                 return -ENODEV;
         }
 
-        r = rtnl_set_properties(ctx->rtnl, ifindex, config->name, config->mac, config->mtu);
+        if (config->name_policy && enable_name_policy()) {
+                char **policy;
+
+                STRV_FOREACH(policy, config->name_policy) {
+                        if (streq(*policy, "onboard")) {
+                                new_name = udev_device_get_property_value(device, "ID_NET_NAME_ONBOARD");
+                                if (new_name)
+                                        break;
+                        } else if (streq(*policy, "slot")) {
+                                new_name = udev_device_get_property_value(device, "ID_NET_NAME_SLOT");
+                                if (new_name)
+                                        break;
+                        } else if (streq(*policy, "path")) {
+                                new_name = udev_device_get_property_value(device, "ID_NET_NAME_PATH");
+                                if (new_name)
+                                        break;
+                        } else if (streq(*policy, "mac")) {
+                                new_name = udev_device_get_property_value(device, "ID_NET_NAME_MAC");
+                                if (new_name)
+                                        break;
+                        } else
+                                log_warning("Invalid link naming policy '%s', ignoring.", *policy);
+                }
+        }
+
+        if (!new_name && config->name)
+                new_name = config->name;
+
+        r = rtnl_set_properties(ctx->rtnl, ifindex, new_name, config->mac, config->mtu);
         if (r < 0) {
                 log_warning("Could not set Name, MACAddress or MTU on %s", name);
                 return r;
diff --git a/src/udev/net/link-config.h b/src/udev/net/link-config.h
index 849e481520..0f57dc9cbc 100644
--- a/src/udev/net/link-config.h
+++ b/src/udev/net/link-config.h
@@ -39,6 +39,7 @@ struct link_config {
 
         char *description;
         char *mac;
+        char **name_policy;
         char *name;
         unsigned int mtu;
         unsigned int speed;