> 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>

Acked-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.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
>