[PATCH] ip6_tunnel: allow to change mode for the ip6tnl0

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* [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0
@ 2014-10-29  6:24 Alexey Andriyanov
  2014-10-29  6:46 ` Eric Dumazet
  2014-10-29  7:54 ` [PATCH v2] " Alexey Andriyanov
  0 siblings, 2 replies; 5+ messages in thread
From: Alexey Andriyanov @ 2014-10-29  6:24 UTC (permalink / raw)
  To: netdev; +Cc: Alexey Andriyanov, David S. Miller, Eric Dumazet

The fallback device is in ipv6 mode by default.
The mode can not be changed in runtime, so there
is no way to decapsulate ip4in6 packets coming from
various sources without creating the specific tunnel
ifaces for each peer.

This allows to update the fallback tunnel device, but only
the mode could be changed. Usual command should work for the
fallback device: `ip -6 tun change ip6tnl0 mode any`

The fallback device can not be hidden from the packet receiver
as a regular tunnel, but there is no need for synchronization
as long as we do single assignment.

Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexey Andriyanov <alan@al-an.info>
---
 net/ipv6/ip6_tunnel.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9409887..303c4dd 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1285,6 +1285,14 @@ static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
 	return err;
 }
 
+static int ip6_tnl0_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
+{
+	/* for default tnl0 device allow to change only the proto */
+	t->parms.proto = p->proto;
+	netdev_state_change(t->dev);
+	return 0;
+}
+
 static void
 ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
 {
@@ -1384,7 +1392,7 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 			break;
 		ip6_tnl_parm_from_user(&p1, &p);
 		t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
-		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
+		if (cmd == SIOCCHGTUNNEL) {
 			if (t != NULL) {
 				if (t->dev != dev) {
 					err = -EEXIST;
@@ -1392,8 +1400,10 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 				}
 			} else
 				t = netdev_priv(dev);
-
-			err = ip6_tnl_update(t, &p1);
+			if (dev == ip6n->fb_tnl_dev)
+				err = ip6_tnl0_update(t, &p1);
+			else
+				err = ip6_tnl_update(t, &p1);
 		}
 		if (t) {
 			err = 0;
-- 
1.9.1

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0
  2014-10-29  6:24 [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0 Alexey Andriyanov
@ 2014-10-29  6:46 ` Eric Dumazet
  2014-10-29  7:46   ` Alexey Andriyanov
  2014-10-29  7:54 ` [PATCH v2] " Alexey Andriyanov
  1 sibling, 1 reply; 5+ messages in thread
From: Eric Dumazet @ 2014-10-29  6:46 UTC (permalink / raw)
  To: Alexey Andriyanov; +Cc: netdev, David S. Miller, Eric Dumazet

On Wed, 2014-10-29 at 09:24 +0300, Alexey Andriyanov wrote:

...
> The fallback device can not be hidden from the packet receiver
> as a regular tunnel, but there is no need for synchronization
> as long as we do single assignment.

This is not exact, I believe you need to add following changes :

 net/ipv6/ip6_tunnel.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9409887fb664dd78d13937b89ea1b5044afdbc94..9d43b99073d656a5a8a38976ca593a41b3cbdca4 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -477,6 +477,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 	int rel_msg = 0;
 	u8 rel_type = ICMPV6_DEST_UNREACH;
 	u8 rel_code = ICMPV6_ADDR_UNREACH;
+	u8 tproto;
 	__u32 rel_info = 0;
 	__u16 len;
 	int err = -ENOENT;
@@ -490,7 +491,8 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 					&ipv6h->saddr)) == NULL)
 		goto out;
 
-	if (t->parms.proto != ipproto && t->parms.proto != 0)
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if (tproto != ipproto && tproto != 0)
 		goto out;
 
 	err = 0;
@@ -791,6 +793,7 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
 {
 	struct ip6_tnl *t;
 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	u8 tproto;
 	int err;
 
 	rcu_read_lock();
@@ -799,7 +802,8 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
 					&ipv6h->daddr)) != NULL) {
 		struct pcpu_sw_netstats *tstats;
 
-		if (t->parms.proto != ipproto && t->parms.proto != 0) {
+		tproto = ACCESS_ONCE(t->parms.proto);
+		if (tproto != ipproto && tproto != 0) {
 			rcu_read_unlock();
 			goto discard;
 		}
@@ -1078,9 +1082,11 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct flowi6 fl6;
 	__u8 dsfield;
 	__u32 mtu;
+	u8 tproto;
 	int err;
 
-	if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPIP && tproto != 0) ||
 	    !ip6_tnl_xmit_ctl(t))
 		return -1;
 
@@ -1120,9 +1126,11 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct flowi6 fl6;
 	__u8 dsfield;
 	__u32 mtu;
+	u8 tproto;
 	int err;
 
-	if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
 	    !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
 		return -1;
 

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0
  2014-10-29  6:46 ` Eric Dumazet
@ 2014-10-29  7:46   ` Alexey Andriyanov
  0 siblings, 0 replies; 5+ messages in thread
From: Alexey Andriyanov @ 2014-10-29  7:46 UTC (permalink / raw)
  To: Eric Dumazet; +Cc: netdev, David S. Miller, Eric Dumazet



29.10.2014 09:46, Eric Dumazet wrote:
> ...
>> The fallback device can not be hidden from the packet receiver
>> as a regular tunnel, but there is no need for synchronization
>> as long as we do single assignment.
> 
> This is not exact, I believe you need to add following changes :

Thank you, Eric, you're right, I missed that.
I'll repost the patch with your changes applied.

-- 
Best regards,
Alexey 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v2] ip6_tunnel: allow to change mode for the ip6tnl0
  2014-10-29  6:24 [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0 Alexey Andriyanov
  2014-10-29  6:46 ` Eric Dumazet
@ 2014-10-29  7:54 ` Alexey Andriyanov
  2014-10-30 20:09   ` David Miller
  1 sibling, 1 reply; 5+ messages in thread
From: Alexey Andriyanov @ 2014-10-29  7:54 UTC (permalink / raw)
  To: netdev; +Cc: Alexey Andriyanov, David S. Miller, Eric Dumazet

The fallback device is in ipv6 mode by default.
The mode can not be changed in runtime, so there
is no way to decapsulate ip4in6 packets coming from
various sources without creating the specific tunnel
ifaces for each peer.

This allows to update the fallback tunnel device, but only
the mode could be changed. Usual command should work for the
fallback device: `ip -6 tun change ip6tnl0 mode any`

The fallback device can not be hidden from the packet receiver
as a regular tunnel, but there is no need for synchronization
as long as we do single assignment.

Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexey Andriyanov <alan@al-an.info>
---
 net/ipv6/ip6_tunnel.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9409887..8c97cd1 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -477,6 +477,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 	int rel_msg = 0;
 	u8 rel_type = ICMPV6_DEST_UNREACH;
 	u8 rel_code = ICMPV6_ADDR_UNREACH;
+	u8 tproto;
 	__u32 rel_info = 0;
 	__u16 len;
 	int err = -ENOENT;
@@ -490,7 +491,8 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 					&ipv6h->saddr)) == NULL)
 		goto out;
 
-	if (t->parms.proto != ipproto && t->parms.proto != 0)
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if (tproto != ipproto && tproto != 0)
 		goto out;
 
 	err = 0;
@@ -791,6 +793,7 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
 {
 	struct ip6_tnl *t;
 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	u8 tproto;
 	int err;
 
 	rcu_read_lock();
@@ -799,7 +802,8 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
 					&ipv6h->daddr)) != NULL) {
 		struct pcpu_sw_netstats *tstats;
 
-		if (t->parms.proto != ipproto && t->parms.proto != 0) {
+		tproto = ACCESS_ONCE(t->parms.proto);
+		if (tproto != ipproto && tproto != 0) {
 			rcu_read_unlock();
 			goto discard;
 		}
@@ -1078,9 +1082,11 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct flowi6 fl6;
 	__u8 dsfield;
 	__u32 mtu;
+	u8 tproto;
 	int err;
 
-	if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPIP && tproto != 0) ||
 	    !ip6_tnl_xmit_ctl(t))
 		return -1;
 
@@ -1120,9 +1126,11 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct flowi6 fl6;
 	__u8 dsfield;
 	__u32 mtu;
+	u8 tproto;
 	int err;
 
-	if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
 	    !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
 		return -1;
 
@@ -1285,6 +1293,14 @@ static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
 	return err;
 }
 
+static int ip6_tnl0_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
+{
+	/* for default tnl0 device allow to change only the proto */
+	t->parms.proto = p->proto;
+	netdev_state_change(t->dev);
+	return 0;
+}
+
 static void
 ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
 {
@@ -1384,7 +1400,7 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 			break;
 		ip6_tnl_parm_from_user(&p1, &p);
 		t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
-		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
+		if (cmd == SIOCCHGTUNNEL) {
 			if (t != NULL) {
 				if (t->dev != dev) {
 					err = -EEXIST;
@@ -1392,8 +1408,10 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 				}
 			} else
 				t = netdev_priv(dev);
-
-			err = ip6_tnl_update(t, &p1);
+			if (dev == ip6n->fb_tnl_dev)
+				err = ip6_tnl0_update(t, &p1);
+			else
+				err = ip6_tnl_update(t, &p1);
 		}
 		if (t) {
 			err = 0;
-- 
1.9.1

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] ip6_tunnel: allow to change mode for the ip6tnl0
  2014-10-29  7:54 ` [PATCH v2] " Alexey Andriyanov
@ 2014-10-30 20:09   ` David Miller
  0 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2014-10-30 20:09 UTC (permalink / raw)
  To: alan; +Cc: netdev, edumazet

From: "Alexey Andriyanov" <alan@al-an.info>
Date: Wed, 29 Oct 2014 10:54:52 +0300

> The fallback device is in ipv6 mode by default.
> The mode can not be changed in runtime, so there
> is no way to decapsulate ip4in6 packets coming from
> various sources without creating the specific tunnel
> ifaces for each peer.
> 
> This allows to update the fallback tunnel device, but only
> the mode could be changed. Usual command should work for the
> fallback device: `ip -6 tun change ip6tnl0 mode any`
> 
> The fallback device can not be hidden from the packet receiver
> as a regular tunnel, but there is no need for synchronization
> as long as we do single assignment.
> 
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Alexey Andriyanov <alan@al-an.info>

Applied to net-next, thanks.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2014-10-30 20:09 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-10-29  6:24 [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0 Alexey Andriyanov
2014-10-29  6:46 ` Eric Dumazet
2014-10-29  7:46   ` Alexey Andriyanov
2014-10-29  7:54 ` [PATCH v2] " Alexey Andriyanov
2014-10-30 20:09   ` David Miller

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