[PATCH net-next 7/9] sit: dynamically allocate struct ip_tunnel_parm_kern

[Eric Dumazet <edumazet@google.com>]

In preparation for converting SIT configuration parameters to RCU,
dynamically allocate struct ip_tunnel_parm_kern as sit_parms in
struct ip_tunnel.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/ip_tunnels.h |   1 +
 net/ipv6/sit.c           | 152 +++++++++++++++++++++++----------------
 2 files changed, 92 insertions(+), 61 deletions(-)

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 7fff59bab53b682ac0d1efd1f47082ba7d633fd2..f464c4480edaf35f9ace1c5081c564ce51fed636 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -190,6 +190,7 @@ struct ip_tunnel {
 #endif
 	struct ip_tunnel_prl_entry __rcu *prl;	/* potential router list */
 	unsigned int		prl_count;	/* # of entries in PRL */
+	struct ip_tunnel_parm_kern *sit_parms;
 	unsigned int		ip_tnl_net_id;
 	struct gro_cells	gro_cells;
 	__u32			fwmark;
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 35c6695909014a2c335f1de7afb48f07b7c91c39..dc37c7109af5324f2ced0301b289e7622dd1a55f 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -108,24 +108,24 @@ static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
 	int ifindex = dev ? dev->ifindex : 0;
 
 	for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
-		if (local == t->parms.iph.saddr &&
-		    remote == t->parms.iph.daddr &&
-		    (!dev || !t->parms.link || ifindex == t->parms.link ||
-		     sifindex == t->parms.link) &&
+		if (local == t->sit_parms->iph.saddr &&
+		    remote == t->sit_parms->iph.daddr &&
+		    (!dev || !t->sit_parms->link || ifindex == t->sit_parms->link ||
+		     sifindex == t->sit_parms->link) &&
 		    (t->dev->flags & IFF_UP))
 			return t;
 	}
 	for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
-		if (remote == t->parms.iph.daddr &&
-		    (!dev || !t->parms.link || ifindex == t->parms.link ||
-		     sifindex == t->parms.link) &&
+		if (remote == t->sit_parms->iph.daddr &&
+		    (!dev || !t->sit_parms->link || ifindex == t->sit_parms->link ||
+		     sifindex == t->sit_parms->link) &&
 		    (t->dev->flags & IFF_UP))
 			return t;
 	}
 	for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
-		if (local == t->parms.iph.saddr &&
-		    (!dev || !t->parms.link || ifindex == t->parms.link ||
-		     sifindex == t->parms.link) &&
+		if (local == t->sit_parms->iph.saddr &&
+		    (!dev || !t->sit_parms->link || ifindex == t->sit_parms->link ||
+		     sifindex == t->sit_parms->link) &&
 		    (t->dev->flags & IFF_UP))
 			return t;
 	}
@@ -157,7 +157,7 @@ __ipip6_bucket(struct sit_net *sitn, struct ip_tunnel_parm_kern *parms)
 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 		struct ip_tunnel *t)
 {
-	return __ipip6_bucket(sitn, &t->parms);
+	return __ipip6_bucket(sitn, t->sit_parms);
 }
 
 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
@@ -236,10 +236,11 @@ static int ipip6_tunnel_create(struct net_device *dev)
 	if (err < 0)
 		goto out;
 
-	__dev_addr_set(dev, &t->parms.iph.saddr, 4);
-	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
+	t->parms = *t->sit_parms;
+	__dev_addr_set(dev, &t->sit_parms->iph.saddr, 4);
+	memcpy(dev->broadcast, &t->sit_parms->iph.daddr, 4);
 
-	if (test_bit(IP_TUNNEL_SIT_ISATAP_BIT, t->parms.i_flags))
+	if (test_bit(IP_TUNNEL_SIT_ISATAP_BIT, t->sit_parms->i_flags))
 		dev->priv_flags |= IFF_ISATAP;
 
 	dev->rtnl_link_ops = &sit_link_ops;
@@ -270,9 +271,9 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 	for (tp = __ipip6_bucket(sitn, parms);
 	    (t = rtnl_dereference(*tp)) != NULL;
 	     tp = &t->next) {
-		if (local == t->parms.iph.saddr &&
-		    remote == t->parms.iph.daddr &&
-		    parms->link == t->parms.link) {
+		if (local == t->sit_parms->iph.saddr &&
+		    remote == t->sit_parms->iph.daddr &&
+		    parms->link == t->sit_parms->link) {
 			if (create)
 				return NULL;
 			else
@@ -299,7 +300,10 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 	nt = netdev_priv(dev);
 
 	nt->net = net;
-	nt->parms = *parms;
+	nt->sit_parms = kmalloc_obj(*nt->sit_parms);
+	if (!nt->sit_parms)
+		goto failed_free;
+	*nt->sit_parms = *parms;
 	if (ipip6_tunnel_create(dev) < 0)
 		goto failed_free;
 
@@ -602,12 +606,12 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
 
 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
-				 t->parms.link, iph->protocol);
+				 t->sit_parms->link, iph->protocol);
 		err = 0;
 		goto out;
 	}
 	if (type == ICMP_REDIRECT) {
-		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
+		ipv4_redirect(skb, dev_net(skb->dev), t->sit_parms->link,
 			      iph->protocol);
 		err = 0;
 		goto out;
@@ -618,10 +622,10 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
 	    !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 		goto out;
 
-	if (t->parms.iph.daddr == 0)
+	if (t->sit_parms->iph.daddr == 0)
 		goto out;
 
-	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
+	if (t->sit_parms->iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 		goto out;
 
 	if (time_before(jiffies, READ_ONCE(t->err_time) + IPTUNNEL_ERR_TIMEO))
@@ -722,8 +726,8 @@ static int ipip6_rcv(struct sk_buff *skb)
 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 				     iph->saddr, iph->daddr, sifindex);
 	if (tunnel) {
-		if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
-		    tunnel->parms.iph.protocol != 0)
+		if (tunnel->sit_parms->iph.protocol != IPPROTO_IPV6 &&
+		    tunnel->sit_parms->iph.protocol != 0)
 			goto out;
 
 		skb->mac_header = skb->network_header;
@@ -798,8 +802,8 @@ static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 	if (tunnel) {
 		const struct tnl_ptk_info *tpi;
 
-		if (tunnel->parms.iph.protocol != ipproto &&
-		    tunnel->parms.iph.protocol != 0)
+		if (tunnel->sit_parms->iph.protocol != ipproto &&
+		    tunnel->sit_parms->iph.protocol != 0)
 			goto drop;
 
 		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
@@ -938,9 +942,9 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 				     struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	const struct iphdr  *tiph = &tunnel->parms.iph;
+	const struct iphdr  *tiph = &tunnel->sit_parms->iph;
 	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
-	u8     tos = tunnel->parms.iph.tos;
+	u8     tos = tunnel->sit_parms->iph.tos;
 	__be16 df = tiph->frag_off;
 	struct rtable *rt;		/* Route to the other host */
 	struct net_device *tdev;	/* Device to other host */
@@ -966,7 +970,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 	if (!dst && !ipip6_tunnel_dst_find(skb, &dst, false))
 		goto tx_error;
 
-	flowi4_init_output(&fl4, tunnel->parms.link, READ_ONCE(tunnel->fwmark),
+	flowi4_init_output(&fl4, tunnel->sit_parms->link, READ_ONCE(tunnel->fwmark),
 			   tos & INET_DSCP_MASK, RT_SCOPE_UNIVERSE,
 			   IPPROTO_IPV6, 0, dst, tiph->saddr, 0, 0,
 			   sock_net_uid(tunnel->net, NULL));
@@ -1014,7 +1018,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 			df = 0;
 		}
 
-		if (tunnel->parms.iph.daddr)
+		if (tunnel->sit_parms->iph.daddr)
 			skb_dst_update_pmtu_no_confirm(skb, mtu);
 
 		if (skb->len > mtu && !skb_is_gso(skb)) {
@@ -1083,7 +1087,7 @@ static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
 				     struct net_device *dev, u8 ipproto)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	const struct iphdr  *tiph = &tunnel->parms.iph;
+	const struct iphdr  *tiph = &tunnel->sit_parms->iph;
 
 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
 		goto tx_error;
@@ -1138,7 +1142,7 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 	const struct iphdr *iph;
 	struct flowi4 fl4;
 
-	iph = &tunnel->parms.iph;
+	iph = &tunnel->sit_parms->iph;
 
 	if (iph->daddr) {
 		struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
@@ -1147,7 +1151,7 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 							  0, 0,
 							  IPPROTO_IPV6,
 							  iph->tos & INET_DSCP_MASK,
-							  tunnel->parms.link);
+							  tunnel->sit_parms->link);
 
 		if (!IS_ERR(rt)) {
 			tdev = rt->dst.dev;
@@ -1156,8 +1160,8 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 		dev->flags |= IFF_POINTOPOINT;
 	}
 
-	if (!tdev && tunnel->parms.link)
-		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
+	if (!tdev && tunnel->sit_parms->link)
+		tdev = __dev_get_by_index(tunnel->net, tunnel->sit_parms->link);
 
 	if (tdev && !netif_is_l3_master(tdev)) {
 		int mtu;
@@ -1171,30 +1175,41 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 	dev->needed_headroom = ip_tunnel_limit_headroom(t_hlen + hlen);
 }
 
-static void ipip6_tunnel_update(struct ip_tunnel *t,
-				struct ip_tunnel_parm_kern *p,
-				__u32 fwmark)
+static int ipip6_tunnel_update(struct ip_tunnel *t,
+			       struct ip_tunnel_parm_kern *p,
+			       __u32 fwmark)
 {
 	struct net *net = t->net;
 	struct sit_net *sitn = net_generic(net, sit_net_id);
+	struct ip_tunnel_parm_kern *new_p, *old_p;
 
+	old_p = t->sit_parms;
+	new_p = kmalloc_obj(*new_p);
+	if (!new_p)
+		return -ENOMEM;
+	*new_p = *old_p;
+	new_p->iph.saddr = p->iph.saddr;
+	new_p->iph.daddr = p->iph.daddr;
+	new_p->iph.ttl = p->iph.ttl;
+	new_p->iph.tos = p->iph.tos;
+	new_p->iph.frag_off = p->iph.frag_off;
+	new_p->link = p->link;
 	ipip6_tunnel_unlink(sitn, t);
 	synchronize_net();
-	t->parms.iph.saddr = p->iph.saddr;
-	t->parms.iph.daddr = p->iph.daddr;
+	t->sit_parms = new_p;
+	t->parms.iph = new_p->iph;
+	WRITE_ONCE(t->parms.link, new_p->link);
 	__dev_addr_set(t->dev, &p->iph.saddr, 4);
 	memcpy(t->dev->broadcast, &p->iph.daddr, 4);
 	ipip6_tunnel_link(sitn, t);
-	t->parms.iph.ttl = p->iph.ttl;
-	t->parms.iph.tos = p->iph.tos;
-	t->parms.iph.frag_off = p->iph.frag_off;
-	if (t->parms.link != p->link || t->fwmark != fwmark) {
-		t->parms.link = p->link;
+	if (old_p->link != p->link || t->fwmark != fwmark) {
 		WRITE_ONCE(t->fwmark, fwmark);
 		ipip6_tunnel_bind_dev(t->dev);
 	}
 	dst_cache_reset(&t->dst_cache);
 	netdev_state_change(t->dev);
+	kfree(old_p);
+	return 0;
 }
 
 #ifdef CONFIG_IPV6_SIT_6RD
@@ -1326,7 +1341,7 @@ ipip6_tunnel_get(struct net_device *dev, struct ip_tunnel_parm_kern *p)
 		t = ipip6_tunnel_locate(t->net, p, 0);
 	if (!t)
 		t = netdev_priv(dev);
-	memcpy(p, &t->parms, sizeof(*p));
+	memcpy(p, t->sit_parms, sizeof(*p));
 	return 0;
 }
 
@@ -1371,7 +1386,9 @@ ipip6_tunnel_change(struct net_device *dev, struct ip_tunnel_parm_kern *p)
 			t = netdev_priv(dev);
 		}
 
-		ipip6_tunnel_update(t, p, t->fwmark);
+		err = ipip6_tunnel_update(t, p, t->fwmark);
+		if (err)
+			return err;
 	}
 
 	return 0;
@@ -1448,7 +1465,7 @@ static int ipip6_get_iflink(const struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
 
-	return READ_ONCE(tunnel->parms.link);
+	return READ_ONCE(tunnel->sit_parms->link);
 }
 
 static const struct net_device_ops ipip6_netdev_ops = {
@@ -1470,6 +1487,8 @@ static void ipip6_dev_free(struct net_device *dev)
 	RCU_INIT_POINTER(tunnel->ip6rd, NULL);
 	kfree(ip6rd);
 #endif
+	kfree(tunnel->sit_parms);
+	tunnel->sit_parms = NULL;
 	if (tunnel->dst_cache.cache) {
 		dst_cache_destroy(&tunnel->dst_cache);
 		tunnel->dst_cache.cache = NULL;
@@ -1512,7 +1531,7 @@ static int ipip6_tunnel_init(struct net_device *dev)
 	int err;
 
 	tunnel->dev = dev;
-	strscpy(tunnel->parms.name, dev->name);
+	strscpy(tunnel->sit_parms->name, dev->name);
 
 	ipip6_tunnel_bind_dev(dev);
 
@@ -1528,15 +1547,9 @@ static int ipip6_tunnel_init(struct net_device *dev)
 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	struct iphdr *iph = &tunnel->parms.iph;
 	struct net *net = dev_net(dev);
 	struct sit_net *sitn = net_generic(net, sit_net_id);
 
-	iph->version		= 4;
-	iph->protocol		= IPPROTO_IPV6;
-	iph->ihl		= 5;
-	iph->ttl		= 64;
-
 	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
 }
 
@@ -1623,6 +1636,7 @@ static int ipip6_newlink(struct net_device *dev,
 #ifdef CONFIG_IPV6_SIT_6RD
 	struct ip_tunnel_6rd ip6rd;
 #endif
+	struct ip_tunnel_parm_kern p;
 	struct net *net;
 	int err;
 
@@ -1636,11 +1650,16 @@ static int ipip6_newlink(struct net_device *dev,
 			return err;
 	}
 
-	ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
+	ipip6_netlink_parms(data, &p, &nt->fwmark);
 
-	if (ipip6_tunnel_locate(net, &nt->parms, 0))
+	if (ipip6_tunnel_locate(net, &p, 0))
 		return -EEXIST;
 
+	nt->sit_parms = kmalloc_obj(*nt->sit_parms);
+	if (!nt->sit_parms)
+		return -ENOMEM;
+	*nt->sit_parms = p;
+
 	err = ipip6_tunnel_create(dev);
 	if (err < 0) {
 		ipip6_dev_free(dev);
@@ -1707,7 +1726,9 @@ static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
 	} else
 		t = netdev_priv(dev);
 
-	ipip6_tunnel_update(t, &p, fwmark);
+	err = ipip6_tunnel_update(t, &p, fwmark);
+	if (err)
+		return err;
 
 #ifdef CONFIG_IPV6_SIT_6RD
 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
@@ -1762,7 +1783,7 @@ static size_t ipip6_get_size(const struct net_device *dev)
 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	struct ip_tunnel_parm_kern *parm = &tunnel->parms;
+	struct ip_tunnel_parm_kern *parm = tunnel->sit_parms;
 #ifdef CONFIG_IPV6_SIT_6RD
 	const struct ip_tunnel_6rd_parm *ip6rd;
 #endif
@@ -1935,6 +1956,17 @@ static int __net_init sit_init_net(struct net *net)
 
 	t = netdev_priv(sitn->fb_tunnel_dev);
 	t->net = net;
+	t->sit_parms = kzalloc_obj(*t->sit_parms);
+	if (!t->sit_parms) {
+		err = -ENOMEM;
+		goto err_reg_dev;
+	}
+	t->sit_parms->iph.version	= 4;
+	t->sit_parms->iph.protocol	= IPPROTO_IPV6;
+	t->sit_parms->iph.ihl		= 5;
+	t->sit_parms->iph.ttl		= 64;
+	strscpy(t->sit_parms->name, sitn->fb_tunnel_dev->name);
+	t->parms = *t->sit_parms;
 
 	err = ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
 	if (err < 0)
@@ -1945,8 +1977,6 @@ static int __net_init sit_init_net(struct net *net)
 		goto err_reg_dev;
 
 	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
-
-	strscpy(t->parms.name, sitn->fb_tunnel_dev->name);
 	return 0;
 
 err_reg_dev:
-- 
2.55.0.979.g7e5102b832-goog