libnm/doc: clarify use of "ipv[46].gateway in nm-settings manual

2 files changed, 8 insertions, 4 deletions

diff --git a/clients/common/settings-docs.h.in b/clients/common/settings-docs.h.in
index 8415b82c5a..0bb88c6973 100644
--- a/clients/common/settings-docs.h.in
+++ b/clients/common/settings-docs.h.in
@@ -224,7 +224,7 @@
 #define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_DNS_OPTIONS N_("Array of DNS options as described in man 5 resolv.conf. NULL means that the options are unset and left at the default. In this case NetworkManager will use default options. This is distinct from an empty list of properties. The currently supported options are \"attempts\", \"debug\", \"edns0\", \"inet6\", \"ip6-bytestring\", \"ip6-dotint\", \"ndots\", \"no-check-names\", \"no-ip6-dotint\", \"no-reload\", \"no-tld-query\", \"rotate\", \"single-request\", \"single-request-reopen\", \"timeout\", \"trust-ad\", \"use-vc\". The \"trust-ad\" setting is only honored if the profile contributes name servers to resolv.conf, and if all contributing profiles have \"trust-ad\" enabled.")
 #define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_DNS_PRIORITY N_("DNS servers priority. The relative priority for DNS servers specified by this setting.  A lower value is better (higher priority). Zero selects a globally configured default value. If the latter is missing or zero too, it defaults to 50 for VPNs (including WireGuard) and 100 for other connections. Note that the priority is to order DNS settings for multiple active connections.  It does not disambiguate multiple DNS servers within the same connection profile. When using dns=default, servers with higher priority will be on top of resolv.conf.  To prioritize a given server over another one within the same connection, just specify them in the desired order.  When multiple devices have configurations with the same priority, VPNs will be considered first, then devices with the best (lowest metric) default route and then all other devices.  Negative values have the special effect of excluding other configurations with a greater priority value; so in presence of at least one negative priority, only DNS servers from connections with the lowest priority value will be used. When using a DNS resolver that supports Conditional Forwarding as dns=dnsmasq or dns=systemd-resolved, each connection is used to query domains in its search list.  Queries for domains not present in any search list are routed through connections having the '~.' special wildcard domain, which is added automatically to connections with the default route (or can be added manually).  When multiple connections specify the same domain, the one with the highest priority (lowest numerical value) wins.  If a connection specifies a domain which is subdomain of another domain with a negative DNS priority value, the subdomain is ignored.")
 #define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_DNS_SEARCH N_("Array of DNS search domains. Domains starting with a tilde ('~') are considered 'routing' domains and are used only to decide the interface over which a query must be forwarded; they are not used to complete unqualified host names.")
-#define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_GATEWAY N_("The gateway associated with this configuration. This is only meaningful if \"addresses\" is also set. This also requires \"never-default\" to be unset. Otherwise, the gateway will be cleared during normalization.")
+#define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_GATEWAY N_("The gateway associated with this configuration. This is only meaningful if \"addresses\" is also set. The gateway's main purpose is to control the next hop of the standard default route on the device. Hence, the gateway property conflicts with \"never-default\" and will be automatically dropped if the IP configuration is set to never-default. As an alternative to set the gateway, configure a static default route with /0 as prefix length.")
 #define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_IGNORE_AUTO_DNS N_("When \"method\" is set to \"auto\" and this property to TRUE, automatically configured nameservers and search domains are ignored and only nameservers and search domains specified in the \"dns\" and \"dns-search\" properties, if any, are used.")
 #define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_IGNORE_AUTO_ROUTES N_("When \"method\" is set to \"auto\" and this property to TRUE, automatically configured routes are ignored and only routes specified in the \"routes\" property, if any, are used.")
 #define DESCRIBE_DOC_NM_SETTING_IP4_CONFIG_MAY_FAIL N_("If TRUE, allow overall network configuration to proceed even if the configuration specified by this property times out.  Note that at least one IP configuration must succeed or overall network configuration will still fail.  For example, in IPv6-only networks, setting this property to TRUE on the NMSettingIP4Config allows the overall network configuration to succeed if IPv4 configuration fails but IPv6 configuration completes successfully.")
@@ -246,7 +246,7 @@
 #define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_DNS_OPTIONS N_("Array of DNS options as described in man 5 resolv.conf. NULL means that the options are unset and left at the default. In this case NetworkManager will use default options. This is distinct from an empty list of properties. The currently supported options are \"attempts\", \"debug\", \"edns0\", \"inet6\", \"ip6-bytestring\", \"ip6-dotint\", \"ndots\", \"no-check-names\", \"no-ip6-dotint\", \"no-reload\", \"no-tld-query\", \"rotate\", \"single-request\", \"single-request-reopen\", \"timeout\", \"trust-ad\", \"use-vc\". The \"trust-ad\" setting is only honored if the profile contributes name servers to resolv.conf, and if all contributing profiles have \"trust-ad\" enabled.")
 #define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_DNS_PRIORITY N_("DNS servers priority. The relative priority for DNS servers specified by this setting.  A lower value is better (higher priority). Zero selects a globally configured default value. If the latter is missing or zero too, it defaults to 50 for VPNs (including WireGuard) and 100 for other connections. Note that the priority is to order DNS settings for multiple active connections.  It does not disambiguate multiple DNS servers within the same connection profile. When using dns=default, servers with higher priority will be on top of resolv.conf.  To prioritize a given server over another one within the same connection, just specify them in the desired order.  When multiple devices have configurations with the same priority, VPNs will be considered first, then devices with the best (lowest metric) default route and then all other devices.  Negative values have the special effect of excluding other configurations with a greater priority value; so in presence of at least one negative priority, only DNS servers from connections with the lowest priority value will be used. When using a DNS resolver that supports Conditional Forwarding as dns=dnsmasq or dns=systemd-resolved, each connection is used to query domains in its search list.  Queries for domains not present in any search list are routed through connections having the '~.' special wildcard domain, which is added automatically to connections with the default route (or can be added manually).  When multiple connections specify the same domain, the one with the highest priority (lowest numerical value) wins.  If a connection specifies a domain which is subdomain of another domain with a negative DNS priority value, the subdomain is ignored.")
 #define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_DNS_SEARCH N_("Array of DNS search domains. Domains starting with a tilde ('~') are considered 'routing' domains and are used only to decide the interface over which a query must be forwarded; they are not used to complete unqualified host names.")
-#define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_GATEWAY N_("The gateway associated with this configuration. This is only meaningful if \"addresses\" is also set. This also requires \"never-default\" to be unset. Otherwise, the gateway will be cleared during normalization.")
+#define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_GATEWAY N_("The gateway associated with this configuration. This is only meaningful if \"addresses\" is also set. The gateway's main purpose is to control the next hop of the standard default route on the device. Hence, the gateway property conflicts with \"never-default\" and will be automatically dropped if the IP configuration is set to never-default. As an alternative to set the gateway, configure a static default route with /0 as prefix length.")
 #define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_IGNORE_AUTO_DNS N_("When \"method\" is set to \"auto\" and this property to TRUE, automatically configured nameservers and search domains are ignored and only nameservers and search domains specified in the \"dns\" and \"dns-search\" properties, if any, are used.")
 #define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_IGNORE_AUTO_ROUTES N_("When \"method\" is set to \"auto\" and this property to TRUE, automatically configured routes are ignored and only routes specified in the \"routes\" property, if any, are used.")
 #define DESCRIBE_DOC_NM_SETTING_IP6_CONFIG_IP6_PRIVACY N_("Configure IPv6 Privacy Extensions for SLAAC, described in RFC4941.  If enabled, it makes the kernel generate a temporary IPv6 address in addition to the public one generated from MAC address via modified EUI-64.  This enhances privacy, but could cause problems in some applications, on the other hand.  The permitted values are: -1: unknown, 0: disabled, 1: enabled (prefer public address), 2: enabled (prefer temporary addresses). Having a per-connection setting set to \"-1\" (unknown) means fallback to global configuration \"ipv6.ip6-privacy\". If also global configuration is unspecified or set to \"-1\", fallback to read \"/proc/sys/net/ipv6/conf/default/use_tempaddr\". Note that this setting is distinct from the Stable Privacy addresses that can be enabled with the \"addr-gen-mode\" property's \"stable-privacy\" setting as another way of avoiding host tracking with IPv6 addresses.")
diff --git a/libnm-core/nm-setting-ip-config.c b/libnm-core/nm-setting-ip-config.c
index a004e8f30f..36f09b694b 100644
--- a/libnm-core/nm-setting-ip-config.c
+++ b/libnm-core/nm-setting-ip-config.c
@@ -5686,8 +5686,12 @@ nm_setting_ip_config_class_init (NMSettingIPConfigClass *klass)
 	 * The gateway associated with this configuration. This is only meaningful
 	 * if #NMSettingIPConfig:addresses is also set.
 	 *
-	 * This also requires #NMSettingIPConfig:never-default to be unset. Otherwise,
-	 * the gateway will be cleared during normalization.
+	 * The gateway's main purpose is to control the next hop of the standard default route on the device.
+	 * Hence, the gateway property conflicts with #NMSettingIPConfig:never-default and will be
+	 * automatically dropped if the IP configuration is set to never-default.
+	 *
+	 * As an alternative to set the gateway, configure a static default route with /0 as prefix
+	 * length.
 	 **/
 	obj_properties[PROP_GATEWAY] =
 	    g_param_spec_string (NM_SETTING_IP_CONFIG_GATEWAY, "", "",