ipv6: Create init helper for fib6_nh

Similar to IPv4, consolidate the fib6_nh initialization into a helper.
As a new standalone function, add a cleanup path to put lwtstate on
error.

To avoid modifying fib6_config flags, move the reject check to a helper
that is invoked once by fib6_nh_init to reset the device and then
again in ip6_route_info_create to set the fib6_flags.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_fib.h

@@ -444,6 +444,10 @@ static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
 	return f6i->fib6_nh.nh_dev;
 }
 
+int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+		 struct fib6_config *cfg, gfp_t gfp_flags,
+		 struct netlink_ext_ack *extack);
+
 static inline
 struct lwtunnel_state *fib6_info_nh_lwt(const struct fib6_info *f6i)
 {

net/ipv6/route.c

@@ -2898,17 +2898,142 @@ static int ip6_validate_gw(struct net *net, struct fib6_config *cfg,
 	return err;
 }
 
+static bool fib6_is_reject(u32 flags, struct net_device *dev, int addr_type)
+{
+	if ((flags & RTF_REJECT) ||
+	    (dev && (dev->flags & IFF_LOOPBACK) &&
+	     !(addr_type & IPV6_ADDR_LOOPBACK) &&
+	     !(flags & RTF_LOCAL)))
+		return true;
+
+	return false;
+}
+
+int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+		 struct fib6_config *cfg, gfp_t gfp_flags,
+		 struct netlink_ext_ack *extack)
+{
+	struct net_device *dev = NULL;
+	struct inet6_dev *idev = NULL;
+	int addr_type;
+	int err;
+
+	err = -ENODEV;
+	if (cfg->fc_ifindex) {
+		dev = dev_get_by_index(net, cfg->fc_ifindex);
+		if (!dev)
+			goto out;
+		idev = in6_dev_get(dev);
+		if (!idev)
+			goto out;
+	}
+
+	if (cfg->fc_flags & RTNH_F_ONLINK) {
+		if (!dev) {
+			NL_SET_ERR_MSG(extack,
+				       "Nexthop device required for onlink");
+			goto out;
+		}
+
+		if (!(dev->flags & IFF_UP)) {
+			NL_SET_ERR_MSG(extack, "Nexthop device is not up");
+			err = -ENETDOWN;
+			goto out;
+		}
+
+		fib6_nh->nh_flags |= RTNH_F_ONLINK;
+	}
+
+	if (cfg->fc_encap) {
+		struct lwtunnel_state *lwtstate;
+
+		err = lwtunnel_build_state(cfg->fc_encap_type,
+					   cfg->fc_encap, AF_INET6, cfg,
+					   &lwtstate, extack);
+		if (err)
+			goto out;
+
+		fib6_nh->nh_lwtstate = lwtstate_get(lwtstate);
+	}
+
+	fib6_nh->nh_weight = 1;
+
+	/* We cannot add true routes via loopback here,
+	 * they would result in kernel looping; promote them to reject routes
+	 */
+	addr_type = ipv6_addr_type(&cfg->fc_dst);
+	if (fib6_is_reject(cfg->fc_flags, dev, addr_type)) {
+		/* hold loopback dev/idev if we haven't done so. */
+		if (dev != net->loopback_dev) {
+			if (dev) {
+				dev_put(dev);
+				in6_dev_put(idev);
+			}
+			dev = net->loopback_dev;
+			dev_hold(dev);
+			idev = in6_dev_get(dev);
+			if (!idev) {
+				err = -ENODEV;
+				goto out;
+			}
+		}
+		goto set_dev;
+	}
+
+	if (cfg->fc_flags & RTF_GATEWAY) {
+		err = ip6_validate_gw(net, cfg, &dev, &idev, extack);
+		if (err)
+			goto out;
+
+		fib6_nh->nh_gw = cfg->fc_gateway;
+	}
+
+	err = -ENODEV;
+	if (!dev)
+		goto out;
+
+	if (idev->cnf.disable_ipv6) {
+		NL_SET_ERR_MSG(extack, "IPv6 is disabled on nexthop device");
+		err = -EACCES;
+		goto out;
+	}
+
+	if (!(dev->flags & IFF_UP) && !cfg->fc_ignore_dev_down) {
+		NL_SET_ERR_MSG(extack, "Nexthop device is not up");
+		err = -ENETDOWN;
+		goto out;
+	}
+
+	if (!(cfg->fc_flags & (RTF_LOCAL | RTF_ANYCAST)) &&
+	    !netif_carrier_ok(dev))
+		fib6_nh->nh_flags |= RTNH_F_LINKDOWN;
+
+set_dev:
+	fib6_nh->nh_dev = dev;
+	err = 0;
+out:
+	if (idev)
+		in6_dev_put(idev);
+
+	if (err) {
+		lwtstate_put(fib6_nh->nh_lwtstate);
+		fib6_nh->nh_lwtstate = NULL;
+		if (dev)
+			dev_put(dev);
+	}
+
+	return err;
+}
+
 static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 					      gfp_t gfp_flags,
 					      struct netlink_ext_ack *extack)
 {
 	struct net *net = cfg->fc_nlinfo.nl_net;
 	struct fib6_info *rt = NULL;
-	struct net_device *dev = NULL;
-	struct inet6_dev *idev = NULL;
 	struct fib6_table *table;
-	int addr_type;
 	int err = -EINVAL;
+	int addr_type;
 
 	/* RTF_PCPU is an internal flag; can not be set by userspace */
 	if (cfg->fc_flags & RTF_PCPU) {
@@ -2942,30 +3067,6 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 		goto out;
 	}
 #endif
-	if (cfg->fc_ifindex) {
-		err = -ENODEV;
-		dev = dev_get_by_index(net, cfg->fc_ifindex);
-		if (!dev)
-			goto out;
-		idev = in6_dev_get(dev);
-		if (!idev)
-			goto out;
-	}
-
-	if (cfg->fc_flags & RTNH_F_ONLINK) {
-		if (!dev) {
-			NL_SET_ERR_MSG(extack,
-				       "Nexthop device required for onlink");
-			err = -ENODEV;
-			goto out;
-		}
-
-		if (!(dev->flags & IFF_UP)) {
-			NL_SET_ERR_MSG(extack, "Nexthop device is not up");
-			err = -ENETDOWN;
-			goto out;
-		}
-	}
 
 	err = -ENOBUFS;
 	if (cfg->fc_nlinfo.nlh &&
@@ -3009,18 +3110,10 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 		cfg->fc_protocol = RTPROT_BOOT;
 	rt->fib6_protocol = cfg->fc_protocol;
 
-	addr_type = ipv6_addr_type(&cfg->fc_dst);
-
-	if (cfg->fc_encap) {
-		struct lwtunnel_state *lwtstate;
-
-		err = lwtunnel_build_state(cfg->fc_encap_type,
-					   cfg->fc_encap, AF_INET6, cfg,
-					   &lwtstate, extack);
-		if (err)
-			goto out;
-		rt->fib6_nh.nh_lwtstate = lwtstate_get(lwtstate);
-	}
+	rt->fib6_table = table;
+	rt->fib6_metric = cfg->fc_metric;
+	rt->fib6_type = cfg->fc_type;
+	rt->fib6_flags = cfg->fc_flags;
 
 	ipv6_addr_prefix(&rt->fib6_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);
 	rt->fib6_dst.plen = cfg->fc_dst_len;
@@ -3031,62 +3124,20 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 	ipv6_addr_prefix(&rt->fib6_src.addr, &cfg->fc_src, cfg->fc_src_len);
 	rt->fib6_src.plen = cfg->fc_src_len;
 #endif
-
-	rt->fib6_metric = cfg->fc_metric;
-	rt->fib6_nh.nh_weight = 1;
-
-	rt->fib6_type = cfg->fc_type;
+	err = fib6_nh_init(net, &rt->fib6_nh, cfg, gfp_flags, extack);
+	if (err)
+		goto out;
 
 	/* We cannot add true routes via loopback here,
-	   they would result in kernel looping; promote them to reject routes
+	 * they would result in kernel looping; promote them to reject routes
 	 */
-	if ((cfg->fc_flags & RTF_REJECT) ||
-	    (dev && (dev->flags & IFF_LOOPBACK) &&
-	     !(addr_type & IPV6_ADDR_LOOPBACK) &&
-	     !(cfg->fc_flags & RTF_LOCAL))) {
-		/* hold loopback dev/idev if we haven't done so. */
-		if (dev != net->loopback_dev) {
-			if (dev) {
-				dev_put(dev);
-				in6_dev_put(idev);
-			}
-			dev = net->loopback_dev;
-			dev_hold(dev);
-			idev = in6_dev_get(dev);
-			if (!idev) {
-				err = -ENODEV;
-				goto out;
-			}
-		}
-		rt->fib6_flags = RTF_REJECT|RTF_NONEXTHOP;
-		goto install_route;
-	}
-
-	if (cfg->fc_flags & RTF_GATEWAY) {
-		err = ip6_validate_gw(net, cfg, &dev, &idev, extack);
-		if (err)
-			goto out;
-
-		rt->fib6_nh.nh_gw = cfg->fc_gateway;
-	}
-
-	err = -ENODEV;
-	if (!dev)
-		goto out;
-
-	if (idev->cnf.disable_ipv6) {
-		NL_SET_ERR_MSG(extack, "IPv6 is disabled on nexthop device");
-		err = -EACCES;
-		goto out;
-	}
-
-	if (!(dev->flags & IFF_UP) && !cfg->fc_ignore_dev_down) {
-		NL_SET_ERR_MSG(extack, "Nexthop device is not up");
-		err = -ENETDOWN;
-		goto out;
-	}
+	addr_type = ipv6_addr_type(&cfg->fc_dst);
+	if (fib6_is_reject(cfg->fc_flags, rt->fib6_nh.nh_dev, addr_type))
+		rt->fib6_flags = RTF_REJECT | RTF_NONEXTHOP;
 
 	if (!ipv6_addr_any(&cfg->fc_prefsrc)) {
+		struct net_device *dev = fib6_info_nh_dev(rt);
+
 		if (!ipv6_chk_addr(net, &cfg->fc_prefsrc, dev, 0)) {
 			NL_SET_ERR_MSG(extack, "Invalid source address");
 			err = -EINVAL;
@@ -3097,26 +3148,8 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 	} else
 		rt->fib6_prefsrc.plen = 0;
 
-	rt->fib6_flags = cfg->fc_flags;
-
-install_route:
-	if (!(rt->fib6_flags & (RTF_LOCAL | RTF_ANYCAST)) &&
-	    !netif_carrier_ok(dev))
-		rt->fib6_nh.nh_flags |= RTNH_F_LINKDOWN;
-	rt->fib6_nh.nh_flags |= (cfg->fc_flags & RTNH_F_ONLINK);
-	rt->fib6_nh.nh_dev = dev;
-	rt->fib6_table = table;
-
-	if (idev)
-		in6_dev_put(idev);
-
 	return rt;
 out:
-	if (dev)
-		dev_put(dev);
-	if (idev)
-		in6_dev_put(idev);
-
 	fib6_info_release(rt);
 	return ERR_PTR(err);
 }