Reapply "net: change accept_ra_min_rtr_lft to affect all RA lifetimes"

This reverts commit 935ac73a69.

Bug: 320243175
Change-Id: If51722d74fe9b326d69c96c0cdfca43db6e33b93
Signed-off-by: Carlos Llamas <cmllamas@google.com>

Documentation/networking/ip-sysctl.rst

@@ -1902,11 +1902,11 @@ accept_ra_min_hop_limit - INTEGER
 
 	Default: 1
 
-accept_ra_min_rtr_lft - INTEGER
+accept_ra_min_lft - INTEGER
-	Minimum acceptable router lifetime in Router Advertisement.
+	Minimum acceptable lifetime value in Router Advertisement.
 
-	RAs with a router lifetime less than this value shall be
+	RA sections with a lifetime less than this value shall be
-	ignored. RAs with a router lifetime of 0 are unaffected.
+	ignored. Zero lifetimes stay unaffected.
 
 	Default: 0
 

include/linux/ipv6.h

@@ -33,7 +33,7 @@ struct ipv6_devconf {
 	__s32		max_addresses;
 	__s32		accept_ra_defrtr;
 	__s32		accept_ra_min_hop_limit;
-	__s32		accept_ra_min_rtr_lft;
+	__s32		accept_ra_min_lft;
 	__s32		accept_ra_pinfo;
 	__s32		ignore_routes_with_linkdown;
 #ifdef CONFIG_IPV6_ROUTER_PREF

include/uapi/linux/ipv6.h

@@ -202,7 +202,7 @@ enum {
 	DEVCONF_IOAM6_ID_WIDE,
 	DEVCONF_NDISC_EVICT_NOCARRIER,
 	DEVCONF_ACCEPT_UNTRACKED_NA,
-	DEVCONF_ACCEPT_RA_MIN_RTR_LFT,
+	DEVCONF_ACCEPT_RA_MIN_LFT,
 	DEVCONF_MAX
 };
 

net/ipv6/addrconf.c

@@ -209,7 +209,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.accept_ra_defrtr	= 1,
 	.accept_ra_from_local	= 0,
 	.accept_ra_min_hop_limit= 1,
-	.accept_ra_min_rtr_lft	= 0,
+	.accept_ra_min_lft	= 0,
 	.accept_ra_pinfo	= 1,
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	.accept_ra_rtr_pref	= 1,
@@ -266,7 +266,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 	.accept_ra_defrtr	= 1,
 	.accept_ra_from_local	= 0,
 	.accept_ra_min_hop_limit= 1,
-	.accept_ra_min_rtr_lft	= 0,
+	.accept_ra_min_lft	= 0,
 	.accept_ra_pinfo	= 1,
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	.accept_ra_rtr_pref	= 1,
@@ -2750,6 +2750,9 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 		return;
 	}
 
+	if (valid_lft != 0 && valid_lft < in6_dev->cnf.accept_ra_min_lft)
+		return;
+
 	/*
 	 *	Two things going on here:
 	 *	1) Add routes for on-link prefixes
@@ -5590,7 +5593,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 	array[DEVCONF_DISABLE_POLICY] = cnf->disable_policy;
 	array[DEVCONF_NDISC_TCLASS] = cnf->ndisc_tclass;
 	array[DEVCONF_RPL_SEG_ENABLED] = cnf->rpl_seg_enabled;
-	array[DEVCONF_ACCEPT_RA_MIN_RTR_LFT] = cnf->accept_ra_min_rtr_lft;
+	array[DEVCONF_ACCEPT_RA_MIN_LFT] = cnf->accept_ra_min_lft;
 }
 
 static inline size_t inet6_ifla6_size(void)
@@ -6745,8 +6748,8 @@ static const struct ctl_table addrconf_sysctl[] = {
 		.proc_handler	= proc_dointvec,
 	},
 	{
-		.procname	= "accept_ra_min_rtr_lft",
+		.procname	= "accept_ra_min_lft",
-		.data		= &ipv6_devconf.accept_ra_min_rtr_lft,
+		.data		= &ipv6_devconf.accept_ra_min_lft,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,

net/ipv6/ndisc.c

@@ -1222,8 +1222,6 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 		return;
 	}
 
-	lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
-
 	if (!ipv6_accept_ra(in6_dev)) {
 		ND_PRINTK(2, info,
 			  "RA: %s, did not accept ra for dev: %s\n",
@@ -1231,13 +1229,6 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 		goto skip_linkparms;
 	}
 
-	if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) {
-		ND_PRINTK(2, info,
-			  "RA: router lifetime (%ds) is too short: %s\n",
-			  lifetime, skb->dev->name);
-		goto skip_linkparms;
-	}
-
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
 	/* skip link-specific parameters from interior routers */
 	if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
@@ -1278,6 +1269,14 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 		goto skip_defrtr;
 	}
 
+	lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
+	if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_lft) {
+		ND_PRINTK(2, info,
+			  "RA: router lifetime (%ds) is too short: %s\n",
+			  lifetime, skb->dev->name);
+		goto skip_defrtr;
+	}
+
 	/* Do not accept RA with source-addr found on local machine unless
 	 * accept_ra_from_local is set to true.
 	 */
@@ -1436,13 +1435,6 @@ skip_linkparms:
 		goto out;
 	}
 
-	if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) {
-		ND_PRINTK(2, info,
-			  "RA: router lifetime (%ds) is too short: %s\n",
-			  lifetime, skb->dev->name);
-		goto out;
-	}
-
 #ifdef CONFIG_IPV6_ROUTE_INFO
 	if (!in6_dev->cnf.accept_ra_from_local &&
 	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
@@ -1467,6 +1459,9 @@ skip_linkparms:
 			if (ri->prefix_len == 0 &&
 			    !in6_dev->cnf.accept_ra_defrtr)
 				continue;
+			if (ri->lifetime != 0 &&
+			    ntohl(ri->lifetime) < in6_dev->cnf.accept_ra_min_lft)
+				continue;
 			if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
 				continue;
 			if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)