[patch]: Allow user to set metric on default route learned via Router Advertisement.

patch/kernel-ipv6-ra-metric-sysctl.patch

@@ -0,0 +1,183 @@
+diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
+index 7eb936642..c61c22808 100644
+--- a/Documentation/networking/ip-sysctl.txt
++++ b/Documentation/networking/ip-sysctl.txt
+@@ -1537,6 +1537,16 @@ accept_ra_defrtr - BOOLEAN
+ 	Functional default: enabled if accept_ra is enabled.
+ 			    disabled if accept_ra is disabled.
+
++ra_defrtr_metric - UNSIGNED INTEGER
++	Route metric for default route learned in Router Advertisement. This value
++	will be assigned as metric for the default route learned via IPv6 Router
++	Advertisement. Takes affect only if accept_ra_defrtr is enabled.
++
++	Possible values:
++		1 to 0xFFFFFFFF
++
++		Default: IP6_RT_PRIO_USER i.e. 1024.
++
+ accept_ra_from_local - BOOLEAN
+ 	Accept RA with source-address that is found on local machine
+         if the RA is otherwise proper and able to be accepted.
+diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
+index 8415bf1a9..ab98f5fa2 100644
+--- a/include/linux/ipv6.h
++++ b/include/linux/ipv6.h
+@@ -31,6 +31,7 @@ struct ipv6_devconf {
+ 	__s32		max_desync_factor;
+ 	__s32		max_addresses;
+ 	__s32		accept_ra_defrtr;
++	__u32		ra_defrtr_metric;
+ 	__s32		accept_ra_min_hop_limit;
+ 	__s32		accept_ra_pinfo;
+ 	__s32		ignore_routes_with_linkdown;
+diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
+index 5e26d6186..7087fb5e5 100644
+--- a/include/net/ip6_route.h
++++ b/include/net/ip6_route.h
+@@ -153,7 +153,8 @@ struct fib6_info *rt6_get_dflt_router(struct net *net,
+ 				     struct net_device *dev);
+ struct fib6_info *rt6_add_dflt_router(struct net *net,
+ 				     const struct in6_addr *gwaddr,
+-				     struct net_device *dev, unsigned int pref);
++				     struct net_device *dev, unsigned int pref,
++				     u32 defrtr_usr_metric);
+
+ void rt6_purge_dflt_routers(struct net *net);
+
+diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
+index 9c0f4a92b..481616cc2 100644
+--- a/include/uapi/linux/ipv6.h
++++ b/include/uapi/linux/ipv6.h
+@@ -187,6 +187,7 @@ enum {
+ 	DEVCONF_DISABLE_POLICY,
+ 	DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN,
+ 	DEVCONF_NDISC_TCLASS,
++	DEVCONF_RA_DEFRTR_METRIC,
+ 	DEVCONF_MAX
+ };
+
+diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
+index d71013fff..42fb25093 100644
+--- a/include/uapi/linux/sysctl.h
++++ b/include/uapi/linux/sysctl.h
+@@ -570,6 +570,7 @@ enum {
+ 	NET_IPV6_ACCEPT_SOURCE_ROUTE=25,
+ 	NET_IPV6_ACCEPT_RA_FROM_LOCAL=26,
+ 	NET_IPV6_ACCEPT_RA_RT_INFO_MIN_PLEN=27,
++	NET_IPV6_RA_DEFRTR_METRIC=28,
+ 	__NET_IPV6_MAX
+ };
+
+diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
+index 07148b497..67b5ef45b 100644
+--- a/kernel/sysctl_binary.c
++++ b/kernel/sysctl_binary.c
+@@ -525,6 +525,7 @@ static const struct bin_table bin_net_ipv6_conf_var_table[] = {
+ 	{ CTL_INT,	NET_IPV6_PROXY_NDP,			"proxy_ndp" },
+ 	{ CTL_INT,	NET_IPV6_ACCEPT_SOURCE_ROUTE,		"accept_source_route" },
+ 	{ CTL_INT,	NET_IPV6_ACCEPT_RA_FROM_LOCAL,		"accept_ra_from_local" },
++	{ CTL_INT,	NET_IPV6_RA_DEFRTR_METRIC,		"ra_defrtr_metric" },
+ 	{}
+ };
+
+diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
+index 627cd24b7..fdddc5616 100644
+--- a/net/ipv6/addrconf.c
++++ b/net/ipv6/addrconf.c
+@@ -209,6 +209,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
+ 	.max_desync_factor	= MAX_DESYNC_FACTOR,
+ 	.max_addresses		= IPV6_MAX_ADDRESSES,
+ 	.accept_ra_defrtr	= 1,
++	.ra_defrtr_metric	= IP6_RT_PRIO_USER,
+ 	.accept_ra_from_local	= 0,
+ 	.accept_ra_min_hop_limit= 1,
+ 	.accept_ra_pinfo	= 1,
+@@ -263,6 +264,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
+ 	.max_desync_factor	= MAX_DESYNC_FACTOR,
+ 	.max_addresses		= IPV6_MAX_ADDRESSES,
+ 	.accept_ra_defrtr	= 1,
++	.ra_defrtr_metric	= IP6_RT_PRIO_USER,
+ 	.accept_ra_from_local	= 0,
+ 	.accept_ra_min_hop_limit= 1,
+ 	.accept_ra_pinfo	= 1,
+@@ -5199,6 +5201,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
+ 	array[DEVCONF_MAX_DESYNC_FACTOR] = cnf->max_desync_factor;
+ 	array[DEVCONF_MAX_ADDRESSES] = cnf->max_addresses;
+ 	array[DEVCONF_ACCEPT_RA_DEFRTR] = cnf->accept_ra_defrtr;
++	array[DEVCONF_RA_DEFRTR_METRIC] = cnf->ra_defrtr_metric;
+ 	array[DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT] = cnf->accept_ra_min_hop_limit;
+ 	array[DEVCONF_ACCEPT_RA_PINFO] = cnf->accept_ra_pinfo;
+ #ifdef CONFIG_IPV6_ROUTER_PREF
+@@ -6347,6 +6350,14 @@ static const struct ctl_table addrconf_sysctl[] = {
+ 		.mode		= 0644,
+ 		.proc_handler	= proc_dointvec,
+ 	},
++	{
++		.procname	= "ra_defrtr_metric",
++		.data		= &ipv6_devconf.ra_defrtr_metric,
++		.maxlen		= sizeof(u32),
++		.mode		= 0644,
++		.proc_handler	= proc_douintvec_minmax,
++		.extra1		= (void *)&one,
++	},
+ 	{
+ 		.procname	= "accept_ra_min_hop_limit",
+ 		.data		= &ipv6_devconf.accept_ra_min_hop_limit,
+diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
+index 673a4a932..5dc072809 100644
+--- a/net/ipv6/ndisc.c
++++ b/net/ipv6/ndisc.c
+@@ -1156,6 +1156,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
+ 	struct neighbour *neigh = NULL;
+ 	struct inet6_dev *in6_dev;
+ 	struct fib6_info *rt = NULL;
++	u32 defrtr_usr_metric;
+ 	struct net *net;
+ 	int lifetime;
+ 	struct ndisc_options ndopts;
+@@ -1287,18 +1288,21 @@ static void ndisc_router_discovery(struct sk_buff *skb)
+ 			return;
+ 		}
+ 	}
+-	if (rt && lifetime == 0) {
++	/* Set default route metric if specified by user */
++	defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric;
++	/* delete the route if lifetime is 0 or if metric needs change */
++	if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) {
+ 		ip6_del_rt(net, rt);
+ 		rt = NULL;
+ 	}
+
+-	ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, for dev: %s\n",
+-		  rt, lifetime, skb->dev->name);
++	ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, metric: %d, for dev: %s\n",
++		  rt, lifetime, defrtr_usr_metric, skb->dev->name);
+ 	if (!rt && lifetime) {
+ 		ND_PRINTK(3, info, "RA: adding default router\n");
+
+ 		rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
+-					 skb->dev, pref);
++					 skb->dev, pref, defrtr_usr_metric);
+ 		if (!rt) {
+ 			ND_PRINTK(0, err,
+ 				  "RA: %s failed to add default route\n",
+diff --git a/net/ipv6/route.c b/net/ipv6/route.c
+index 9c36a743d..2ba8e6411 100644
+--- a/net/ipv6/route.c
++++ b/net/ipv6/route.c
+@@ -3608,11 +3608,12 @@ struct fib6_info *rt6_get_dflt_router(struct net *net,
+ struct fib6_info *rt6_add_dflt_router(struct net *net,
+ 				     const struct in6_addr *gwaddr,
+ 				     struct net_device *dev,
+-				     unsigned int pref)
++				     unsigned int pref,
++				     u32 defrtr_usr_metric)
+ {
+ 	struct fib6_config cfg = {
+ 		.fc_table	= l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT,
+-		.fc_metric	= IP6_RT_PRIO_USER,
++		.fc_metric	= defrtr_usr_metric,
+ 		.fc_ifindex	= dev->ifindex,
+ 		.fc_flags	= RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT |
+ 				  RTF_UP | RTF_EXPIRES | RTF_PREF(pref),

patch/series

@@ -36,6 +36,7 @@ e1000-Do-not-perform-reset-in-reset_task-if-we-are-a.patch
 macsec-Support-XPN-frame-handling-IEEE-802.1AEbw.patch
 netlink-add-NLA_MIN_LEN.patch
 macsec-Netlink-support-of-XPN-cipher-suites-IEEE-802.patch
+kernel-ipv6-ra-metric-sysctl.patch
 Support-for-fullcone-nat.patch
 driver-ixgbe-external-phy.patch
 #