Subject: [PATCH RFC net-next 09/18] net/ipv6: Create init and release helpers for fib6_nh

From: [email-masked]
Date: Fri, 31 Aug 2018 17:49:44 -0700

From: David Ahern <[email-masked]>

Refactor initialization and cleanup of fib6_nh to helpers similar to
what was done for IPv4. Add fib6_nh_init to the ipv6 stubs for use by
core code when ipv6 is built as a module.

The replace helper is small enough, so make an inline rather than
requiring it to go through ipv6 stubs.

Signed-off-by: David Ahern <[email-masked]>
---
 include/net/addrconf.h   |   5 +
 include/net/ip6_fib.h    |  11 +++
 net/ipv6/addrconf_core.c |   9 ++
 net/ipv6/af_inet6.c      |   1 +
 net/ipv6/ip6_fib.c       |   5 +-
 net/ipv6/route.c         | 239 +++++++++++++++++++++++++----------------------
 6 files changed, 153 insertions(+), 117 deletions(-)

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 6def0351bcc3..7748b8300ca0 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -2,6 +2,8 @@
 #ifndef _ADDRCONF_H
 #define _ADDRCONF_H
 
+#include <net/ip6_fib.h>
+
 #define MAX_RTR_SOLICITATIONS		-1		/* unlimited */
 #define RTR_SOLICITATION_INTERVAL	(4*HZ)
 #define RTR_SOLICITATION_MAX_INTERVAL	(3600*HZ)	/* 1 hour */
@@ -253,6 +255,9 @@ struct ipv6_stub {
 	u32 (*ip6_mtu_from_fib6)(struct fib6_info *f6i, struct in6_addr *daddr,
 				 struct in6_addr *saddr);
 
+	int (*fib6_nh_init)(struct net *net, struct fib6_nh *fib6_nh,
+			    struct fib6_config *cfg,
+			    struct netlink_ext_ack *extack);
 	void (*udpv6_encap_enable)(void);
 	void (*ndisc_send_na)(struct net_device *dev, const struct in6_addr *daddr,
 			      const struct in6_addr *solicited_addr,
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 3d4930528db0..2a1fae1247a9 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -22,6 +22,7 @@
 #include <net/netlink.h>
 #include <net/inetpeer.h>
 #include <net/fib_notifier.h>
+#include <net/lwtunnel.h>
 
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 #define FIB6_TABLE_HASHSZ 256
@@ -413,6 +414,16 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 	     struct nl_info *info, struct netlink_ext_ack *extack);
 int fib6_del(struct fib6_info *rt, struct nl_info *info);
 
+int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+		 struct fib6_config *cfg, struct netlink_ext_ack *extack);
+static inline void fib6_nh_release(struct fib6_nh *fib6_nh)
+{
+	if (fib6_nh->nh_dev)
+		dev_put(fib6_nh->nh_dev);
+
+	lwtstate_put(fib6_nh->nh_lwtstate);
+}
+
 static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
 {
 	return f6i->fib6_nh.nh_dev;
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index 5cd0029d930e..f5c712136408 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -168,6 +168,14 @@ eafnosupport_ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
 	return 0;
 }
 
+static int eafnosupport_fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+				     struct fib6_config *cfg,
+				     struct netlink_ext_ack *extack)
+{
+	NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
+	return -EAFNOSUPPORT;
+}
+
 const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
 	.ipv6_dst_lookup   = eafnosupport_ipv6_dst_lookup,
 	.fib6_get_table    = eafnosupport_fib6_get_table,
@@ -175,6 +183,7 @@ const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
 	.fib6_lookup       = eafnosupport_fib6_lookup,
 	.fib6_multipath_select = eafnosupport_fib6_multipath_select,
 	.ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
+	.fib6_nh_init	   = eafnosupport_fib6_nh_init,
 };
 EXPORT_SYMBOL_GPL(ipv6_stub);
 
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 673bba31eb18..a5809bf7c229 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -895,6 +895,7 @@ static const struct ipv6_stub ipv6_stub_impl = {
 	.fib6_lookup       = fib6_lookup,
 	.fib6_multipath_select = fib6_multipath_select,
 	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
+	.fib6_nh_init	   = fib6_nh_init,
 	.udpv6_encap_enable = udpv6_encap_enable,
 	.ndisc_send_na = ndisc_send_na,
 	.nd_tbl	= &nd_tbl,
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index c861a6d4671d..c1c23427a81e 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -198,10 +198,7 @@ void fib6_info_destroy_rcu(struct rcu_head *head)
 		}
 	}
 
-	lwtstate_put(f6i->fib6_nh.nh_lwtstate);
-
-	if (f6i->fib6_nh.nh_dev)
-		dev_put(f6i->fib6_nh.nh_dev);
+	fib6_nh_release(&f6i->fib6_nh);
 
 	m = f6i->fib6_metrics;
 	if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 07ed7812c6b4..aa44cd5b3217 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2844,9 +2844,11 @@ static int ip6_route_check_nh(struct net *net,
 		}
 	} else {
 		*_dev = dev = grt->dst.dev;
-		*idev = grt->rt6i_idev;
 		dev_hold(dev);
-		in6_dev_hold(grt->rt6i_idev);
+		if (idev) {
+			*idev = grt->rt6i_idev;
+			in6_dev_hold(grt->rt6i_idev);
+		}
 	}
 
 	if (!(grt->rt6i_flags & RTF_GATEWAY))
@@ -2931,16 +2933,128 @@ static int ip6_validate_gw(struct net *net, struct fib6_config *cfg,
 	return err;
 }
 
+int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+		 struct fib6_config *cfg, 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 ((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;
+			}
+		}
+		cfg->fc_flags = RTF_REJECT | RTF_NONEXTHOP;
+		err = 0;
+		goto out;
+	}
+
+	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)) {
+		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;
+
+	fib6_nh->nh_dev = dev;
+
+out:
+	if (idev)
+		in6_dev_put(idev);
+
+	if (err && 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;
 
 	/* RTF_PCPU is an internal flag; can not be set by userspace */
@@ -2975,34 +3089,9 @@ 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_metric == 0)
 		cfg->fc_metric = IP6_RT_PRIO_USER;
 
-	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 &&
 	    !(cfg->fc_nlinfo.nlh->nlmsg_flags & NLM_F_CREATE)) {
@@ -3040,18 +3129,9 @@ 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;
 
 	ipv6_addr_prefix(&rt->fib6_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);
 	rt->fib6_dst.plen = cfg->fc_dst_len;
@@ -3062,62 +3142,13 @@ 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;
-
-	/* We cannot add true routes via loopback here,
-	   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)
+	err = fib6_nh_init(net, &rt->fib6_nh, cfg, extack);
+	if (err)
 		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)) {
-		NL_SET_ERR_MSG(extack, "Nexthop device is not up");
-		err = -ENETDOWN;
-		goto out;
-	}
-
 	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;
@@ -3130,26 +3161,8 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 
 	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;
-
-	cfg->fc_nlinfo.nl_net = dev_net(dev);
-
-	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);
 }
-- 
2.11.0