[PATCH 04/12] netconfig: Support IPv6 static configurations

[PATCH 04/12] netconfig: Support IPv6 static configurations

[Andrew Zaborowski]

[-- Attachment #1: Type: text/plain, Size: 8939 bytes --]

---
 ell/netconfig.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 177 insertions(+), 5 deletions(-)

diff --git a/ell/netconfig.c b/ell/netconfig.c
index c8a5510..53df690 100644
--- a/ell/netconfig.c
+++ b/ell/netconfig.c
@@ -62,11 +62,13 @@ struct l_netconfig {
 	struct l_idle *do_static_work;
 	bool v4_configured;
 	struct l_dhcp_client *dhcp_client;
+	bool v6_configured;
 
 	/* These objects, if not NULL, are owned by @addresses and @routes */
 	struct l_rtnl_address *v4_address;
 	struct l_rtnl_route *v4_subnet_route;
 	struct l_rtnl_route *v4_default_route;
+	struct l_rtnl_address *v6_address;
 
 	struct {
 		struct l_queue *current;
@@ -159,6 +161,50 @@ static void netconfig_add_v4_routes(struct l_netconfig *nc, const char *ip,
 	l_queue_push_tail(nc->routes.added, nc->v4_default_route);
 }
 
+static void netconfig_add_v6_static_routes(struct l_netconfig *nc,
+						const char *ip,
+						uint8_t prefix_len)
+{
+	struct in6_addr in6_addr;
+	char network[INET6_ADDRSTRLEN];
+	struct l_rtnl_route *v6_subnet_route;
+	struct l_rtnl_route *v6_default_route;
+
+	/* Subnet route */
+
+	if (L_WARN_ON(inet_pton(AF_INET6, ip, &in6_addr) != 1))
+		return;
+
+	/* Zero out host address bits to produce network address */
+	if (prefix_len & 7)
+		in6_addr.s6_addr[prefix_len / 8] &= 0xff00 >> (prefix_len & 7);
+
+	if (prefix_len <= 120)
+		memset(in6_addr.s6_addr + (prefix_len + 7) / 8, 0,
+			16 - (prefix_len + 7) / 8);
+
+	if (L_WARN_ON(!inet_ntop(AF_INET6, &in6_addr, network,
+					INET6_ADDRSTRLEN)))
+		return;
+
+	v6_subnet_route = l_rtnl_route_new_prefix(network, prefix_len);
+	l_rtnl_route_set_protocol(v6_subnet_route, RTPROT_STATIC);
+	l_rtnl_route_set_priority(v6_subnet_route, nc->route_priority);
+	l_queue_push_tail(nc->routes.current, v6_subnet_route);
+	l_queue_push_tail(nc->routes.added, v6_subnet_route);
+
+	/* Gateway route */
+
+	if (!nc->v6_gateway_override)
+		return;
+
+	v6_default_route = l_rtnl_route_new_gateway(nc->v6_gateway_override);
+	l_rtnl_route_set_protocol(v6_default_route, RTPROT_STATIC);
+	L_WARN_ON(!l_rtnl_route_set_prefsrc(v6_default_route, ip));
+	l_queue_push_tail(nc->routes.current, v6_default_route);
+	l_queue_push_tail(nc->routes.added, v6_default_route);
+}
+
 static void netconfig_add_dhcp_address_routes(struct l_netconfig *nc)
 {
 	const struct l_dhcp_lease *lease =
@@ -388,6 +434,9 @@ LIB_EXPORT bool l_netconfig_set_family_enabled(struct l_netconfig *netconfig,
 	case AF_INET:
 		netconfig->v4_enabled = enabled;
 		return true;
+	case AF_INET6:
+		netconfig->v6_enabled = enabled;
+		return true;
 	}
 
 	return false;
@@ -607,11 +656,90 @@ static bool netconfig_check_v4_config(struct l_netconfig *netconfig)
 	return true;
 }
 
+static bool netconfig_check_v6_dns_list(const struct in6_addr *local,
+					uint8_t prefix_len,
+					const struct in6_addr *dns_list,
+					unsigned int dns_num)
+{
+	unsigned int i;
+
+	for (i = 0; i < dns_num; i++)
+		if (!l_net_prefix_matches(local, &dns_list[i], prefix_len) &&
+				!IN6_IS_ADDR_LINKLOCAL(&dns_list[i]))
+			return false;
+
+	return true;
+}
+
+static bool netconfig_check_v6_config(struct l_netconfig *netconfig)
+{
+	struct in6_addr local;
+	struct in6_addr gateway;
+	uint8_t prefix_len = 0;
+	unsigned int dns_num = 0;
+	_auto_(l_free) struct in6_addr *dns_list = NULL;
+
+	if (!netconfig->v6_enabled)
+		return true;
+
+	if (netconfig->v6_static_addr) {
+		char str[INET6_ADDRSTRLEN];
+
+		prefix_len = l_rtnl_address_get_prefix_length(
+						netconfig->v6_static_addr);
+		if (unlikely(prefix_len > 126))
+			return false;
+
+		l_rtnl_address_get_address(netconfig->v6_static_addr, str);
+		inet_pton(AF_INET6, str, &local);
+	}
+
+	if (netconfig->v6_gateway_override) {
+		if (unlikely(inet_pton(AF_INET6, netconfig->v6_gateway_override,
+					&gateway) != 1))
+			return false;
+	}
+
+	if (netconfig->v6_dns_override &&
+			(dns_num = l_strv_length(netconfig->v6_dns_override))) {
+		unsigned int i;
+
+		dns_list = l_new(struct in6_addr, dns_num);
+
+		for (i = 0; i < dns_num; i++)
+			if (inet_pton(AF_INET6, netconfig->v6_dns_override[i],
+					&dns_list[i]) != 1)
+				return false;
+	}
+
+	/*
+	 * If using a static IP, we can validate right now that the gateway IP
+	 * is link-local or is in the local subnet.
+	 */
+	if (netconfig->v6_static_addr && netconfig->v6_gateway_override)
+		if (!l_net_prefix_matches(&local, &gateway, prefix_len) &&
+				!IN6_IS_ADDR_LINKLOCAL(&gateway))
+			return false;
+
+	/*
+	 * If using a static IP and there's no gateway all the DNSes must also
+	 * have link-local addresses or be in our subnet.
+	 */
+	if (netconfig->v6_static_addr && !netconfig->v6_gateway_override &&
+			netconfig->v6_dns_override &&
+			!netconfig_check_v6_dns_list(&local, prefix_len,
+							dns_list, dns_num))
+		return false;
+
+	return true;
+}
+
 static bool netconfig_check_config(struct l_netconfig *netconfig)
 {
 	/* TODO: error reporting through a debug log handler or otherwise */
 
-	return netconfig_check_v4_config(netconfig);
+	return netconfig_check_v4_config(netconfig) &&
+		netconfig_check_v6_config(netconfig);
 }
 
 LIB_EXPORT bool l_netconfig_check_config(struct l_netconfig *netconfig)
@@ -622,7 +750,7 @@ LIB_EXPORT bool l_netconfig_check_config(struct l_netconfig *netconfig)
 	return netconfig_check_config(netconfig);
 }
 
-static void netconfig_add_static_address_routes(struct l_netconfig *nc)
+static void netconfig_add_v4_static_address_routes(struct l_netconfig *nc)
 {
 	char ip[INET_ADDRSTRLEN];
 	uint32_t prefix_len;
@@ -636,6 +764,29 @@ static void netconfig_add_static_address_routes(struct l_netconfig *nc)
 	netconfig_add_v4_routes(nc, ip, prefix_len, NULL, RTPROT_STATIC);
 }
 
+/*
+ * Just mirror the IPv4 behaviour with static IPv6 configuration.  It would
+ * be more logical to let the user choose between static IPv6 address and
+ * DHCPv6, and, completely independently, choose between static routes
+ * (if a static prefix length and/or gateway address is set) and ICMPv6.
+ * Yet a mechanism identical with IPv4 is easier to understand for a typical
+ * user so providing a static address just disables all automatic
+ * configuration.
+ */
+static void netconfig_add_v6_static_address_routes(struct l_netconfig *nc)
+{
+	char ip[INET6_ADDRSTRLEN];
+	uint32_t prefix_len;
+
+	nc->v6_address = l_rtnl_address_clone(nc->v6_static_addr);
+	l_queue_push_tail(nc->addresses.current, nc->v6_address);
+	l_queue_push_tail(nc->addresses.added, nc->v6_address);
+
+	l_rtnl_address_get_address(nc->v6_static_addr, ip);
+	prefix_len = l_rtnl_address_get_prefix_length(nc->v6_static_addr);
+	netconfig_add_v6_static_routes(nc, ip, prefix_len);
+}
+
 static void netconfig_do_static_config(struct l_idle *idle, void *user_data)
 {
 	struct l_netconfig *nc = user_data;
@@ -643,10 +794,16 @@ static void netconfig_do_static_config(struct l_idle *idle, void *user_data)
 	l_idle_remove(l_steal_ptr(nc->do_static_work));
 
 	if (nc->v4_static_addr && !nc->v4_configured) {
-		netconfig_add_static_address_routes(nc);
+		netconfig_add_v4_static_address_routes(nc);
 		nc->v4_configured = true;
 		netconfig_emit_event(nc, AF_INET, L_NETCONFIG_EVENT_CONFIGURE);
 	}
+
+	if (nc->v6_static_addr && !nc->v6_configured) {
+		netconfig_add_v6_static_address_routes(nc);
+		nc->v6_configured = true;
+		netconfig_emit_event(nc, AF_INET6, L_NETCONFIG_EVENT_CONFIGURE);
+	}
 }
 
 LIB_EXPORT bool l_netconfig_start(struct l_netconfig *netconfig)
@@ -658,7 +815,7 @@ LIB_EXPORT bool l_netconfig_start(struct l_netconfig *netconfig)
 		return false;
 
 	if (!netconfig->v4_enabled)
-		goto done;
+		goto configure_ipv6;
 
 	if (netconfig->v4_static_addr) {
 		/*
@@ -668,12 +825,26 @@ LIB_EXPORT bool l_netconfig_start(struct l_netconfig *netconfig)
 		netconfig->do_static_work = l_idle_create(
 						netconfig_do_static_config,
 						netconfig, NULL);
-		goto done;
+		goto configure_ipv6;
 	}
 
 	if (!l_dhcp_client_start(netconfig->dhcp_client))
 		return false;
 
+configure_ipv6:
+	if (!netconfig->v6_enabled)
+		goto done;
+
+	if (netconfig->v6_static_addr && !netconfig->do_static_work) {
+		/*
+		 * We're basically ready to configure the interface
+		 * but do this in an idle callback.
+		 */
+		netconfig->do_static_work = l_idle_create(
+						netconfig_do_static_config,
+						netconfig, NULL);
+	}
+
 done:
 	netconfig->started = true;
 	return true;
@@ -697,6 +868,7 @@ LIB_EXPORT void l_netconfig_stop(struct l_netconfig *netconfig)
 	netconfig->v4_address = NULL;
 	netconfig->v4_subnet_route = NULL;
 	netconfig->v4_default_route = NULL;
+	netconfig->v6_address = NULL;
 
 	l_dhcp_client_stop(netconfig->dhcp_client);
 }
-- 
2.32.0