c/r: IPv6 support

c/r: IPv6 support

[Dan Smith]

This version of the patch set incorporates feedback from Brian, as well
as a new patch at the end to check for IPv4 multicast addresses when
doing the checkpoint.

[PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Dan Smith]

Changes in v2:
 - Store an in6_addr structure in the checkpoint stream
 - Fix network byte order conversion
 - Don't checkpoint and restore non-global scope addresses
 - Fail checkpoint if we find global scope multicast or anycast
   addresses

Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 include/linux/checkpoint.h     |    2 +-
 include/linux/checkpoint_hdr.h |    8 ++
 net/checkpoint_dev.c           |  272 ++++++++++++++++++++++++++++++++--------
 3 files changed, 228 insertions(+), 54 deletions(-)

diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 96693e2..2caa38c 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -132,7 +132,7 @@ extern void *restore_netdev(struct ckpt_ctx *ctx);
 
 extern int ckpt_netdev_in_init_netns(struct ckpt_ctx *ctx,
 				     struct net_device *dev);
-extern int ckpt_netdev_inet_addrs(struct in_device *indev,
+extern int ckpt_netdev_inet_addrs(struct net_device *dev,
 				  struct ckpt_netdev_addr *list[]);
 extern int ckpt_netdev_hwaddr(struct net_device *dev,
 			      struct ckpt_hdr_netdev *h);
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 36386ad..90e4934 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -804,6 +804,7 @@ struct ckpt_hdr_netdev {
 
 enum ckpt_netdev_addr_types {
 	CKPT_NETDEV_ADDR_IPV4,
+	CKPT_NETDEV_ADDR_IPV6,
 };
 
 struct ckpt_netdev_addr {
@@ -815,6 +816,13 @@ struct ckpt_netdev_addr {
 			__be32 inet4_mask;
 			__be32 inet4_broadcast;
 		};
+		struct {
+			struct in6_addr inet6_addr;
+			__u32  inet6_prefix_len;
+			__u32  inet6_valid_lft;
+			__u32  inet6_prefered_lft;
+			__u16  inet6_scope;
+		};
 	} __attribute__((aligned(8)));
 } __attribute__((aligned(8)));
 
diff --git a/net/checkpoint_dev.c b/net/checkpoint_dev.c
index 5a4a95b..776931b 100644
--- a/net/checkpoint_dev.c
+++ b/net/checkpoint_dev.c
@@ -18,8 +18,11 @@
 #include <linux/checkpoint_hdr.h>
 #include <linux/deferqueue.h>
 
+#include <net/if_inet6.h>
+#include <net/ipv6.h>
 #include <net/net_namespace.h>
 #include <net/sch_generic.h>
+#include <net/addrconf.h>
 
 struct veth_newlink {
 	char *peer;
@@ -47,6 +50,24 @@ static int __kern_devinet_ioctl(struct net *net, unsigned int cmd, void *arg)
 	return ret;
 }
 
+#ifdef CONFIG_IPV6
+static int __kern_addrconf(struct net *net, unsigned int cmd, void *arg)
+{
+	mm_segment_t fs;
+	int ret;
+
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	if (cmd == SIOCSIFADDR)
+		ret = addrconf_add_ifaddr(net, arg);
+	else
+		ret = -EINVAL;
+	set_fs(fs);
+
+	return ret;
+}
+#endif
+
 static int __kern_dev_ioctl(struct net *net, unsigned int cmd, void *arg)
 {
 	mm_segment_t fs;
@@ -151,11 +172,109 @@ int ckpt_netdev_hwaddr(struct net_device *dev, struct ckpt_hdr_netdev *h)
 	return 0;
 }
 
-int ckpt_netdev_inet_addrs(struct in_device *indev,
+static int ckpt_netdev_inet4_addrs(struct in_device *indev,
+				   int index, int max,
+				   struct ckpt_netdev_addr *abuf)
+{
+	struct in_ifaddr *addr = indev->ifa_list;
+
+	while (addr) {
+		abuf[index].type = CKPT_NETDEV_ADDR_IPV4;
+		abuf[index].inet4_local = htonl(addr->ifa_local);
+		abuf[index].inet4_address = htonl(addr->ifa_address);
+		abuf[index].inet4_mask = htonl(addr->ifa_mask);
+		abuf[index].inet4_broadcast = htonl(addr->ifa_broadcast);
+
+		addr = addr->ifa_next;
+		if (++index >= max)
+			return -E2BIG;
+	}
+
+	return index;
+}
+
+#ifdef CONFIG_IPV6
+
+#define __BYTE_ORDER_COPY(op, dst, src)					\
+	do {								\
+		int i;							\
+		for (i = 0; i < 16; i++) {				\
+			(dst)->in6_u.u6_addr8[i] =			\
+				(src)->in6_u.u6_addr8[16-i];		\
+		}							\
+	} while (0);
+
+#define HTON_IPV6(dst, src) __BYTE_ORDER_COPY(htonl, dst, src)
+#define NTOH_IPV6(dst, src) __BYTE_ORDER_COPY(ntohl, dst, src)
+
+static int ckpt_netdev_inet6_addrs(struct inet6_dev *indev,
+				   int index, int max,
+				   struct ckpt_netdev_addr *abuf)
+{
+	struct inet6_ifaddr *addr;
+	struct ifmcaddr6 *mcaddr;
+	struct ifacaddr6 *acaddr;
+
+	for (addr = indev->addr_list; addr; addr = addr->if_next) {
+		if (ipv6_addr_scope(&addr->addr))
+			continue; /* Ignore non-global scope addresses */
+
+		abuf[index].type = CKPT_NETDEV_ADDR_IPV6;
+
+		HTON_IPV6(&abuf[index].inet6_addr, &addr->addr);
+
+		ckpt_debug("Checkpointed inet6: %pI6\n", &addr->addr);
+
+		abuf[index].inet6_prefix_len = addr->prefix_len;
+		abuf[index].inet6_valid_lft = addr->valid_lft;
+		abuf[index].inet6_prefered_lft = addr->prefered_lft;
+		abuf[index].inet6_scope = addr->scope;
+
+		if (++index >= max)
+			return -E2BIG;
+	}
+
+	for (mcaddr = indev->mc_list; mcaddr; mcaddr = mcaddr->next) {
+		if (ipv6_addr_scope(&mcaddr->mca_addr))
+			continue; /* Ignore non-global scope addresses */
+
+		/* TODO */
+
+		/* Multicast addresses are not supported, so do not
+		 * allow checkpoint to continue if one is assigned
+		 */
+		ckpt_debug("ipv6 multicast addresses are not supported\n");
+		return -EINVAL;
+	}
+
+	for (acaddr = indev->ac_list; acaddr; acaddr = acaddr->aca_next) {
+		if (ipv6_addr_scope(&acaddr->aca_addr))
+			continue; /* Ignore non-global scope addresses */
+
+		/* TODO */
+
+		/* Anycast addresses are not supported, so do not
+		 * allow checkpoint to continue if one is assigned
+		 */
+		ckpt_debug("ipv6 anycast addresses are not supported\n");
+		return -EINVAL;
+	}
+
+	return index;
+}
+#else
+static int ckpt_netdev_inet6_addrs(struct inet6_dev *indev,
+				   int index, int max,
+				   struct ckpt_netdev_addr *abuf)
+{
+	return -ENOSYS;
+}
+#endif
+
+int ckpt_netdev_inet_addrs(struct net_device *dev,
 			   struct ckpt_netdev_addr *_abuf[])
 {
 	struct ckpt_netdev_addr *abuf = NULL;
-	struct in_ifaddr *addr = indev->ifa_list;
 	int addrs = 0;
 	int max = 32;
 
@@ -169,21 +288,21 @@ int ckpt_netdev_inet_addrs(struct in_device *indev,
 
 	read_lock(&dev_base_lock);
 
-	while (addr) {
-		abuf[addrs].type = CKPT_NETDEV_ADDR_IPV4; /* Only IPv4 now */
-		abuf[addrs].inet4_local = htonl(addr->ifa_local);
-		abuf[addrs].inet4_address = htonl(addr->ifa_address);
-		abuf[addrs].inet4_mask = htonl(addr->ifa_mask);
-		abuf[addrs].inet4_broadcast = htonl(addr->ifa_broadcast);
+	addrs = 0;
 
-		addr = addr->ifa_next;
-		if (++addrs >= max) {
-			read_unlock(&dev_base_lock);
-			max *= 2;
-			goto retry;
-		}
-	}
+	addrs = ckpt_netdev_inet4_addrs(dev->ip_ptr, addrs, max, abuf);
+	if (addrs == -E2BIG) {
+		read_unlock(&dev_base_lock);
+		goto retry;
+	} else if (addrs < 0)
+		goto unlock;
 
+	addrs = ckpt_netdev_inet6_addrs(dev->ip6_ptr, addrs, max, abuf);
+	if (addrs == -E2BIG) {
+		read_unlock(&dev_base_lock);
+		goto retry;
+	}
+ unlock:
 	read_unlock(&dev_base_lock);
  out:
 	if (addrs < 0) {
@@ -210,7 +329,7 @@ struct ckpt_hdr_netdev *ckpt_netdev_base(struct ckpt_ctx *ctx,
 		goto out;
 
 	*addrs = NULL;
-	ret = h->inet_addrs = ckpt_netdev_inet_addrs(dev->ip_ptr, addrs);
+	ret = h->inet_addrs = ckpt_netdev_inet_addrs(dev, addrs);
 	if (ret < 0)
 		goto out;
 
@@ -291,6 +410,85 @@ int checkpoint_netns(struct ckpt_ctx *ctx, void *ptr)
 	return ret;
 }
 
+static int restore_inet4_addr(struct ckpt_ctx *ctx,
+			      struct net_device *dev,
+			      struct net *net,
+			      struct ckpt_netdev_addr *addr)
+{
+	struct ifreq req;
+	struct sockaddr_in *inaddr;
+	int ret;
+
+	ckpt_debug("restoring %s: %x/%x/%x\n",
+		   dev->name,
+		   addr->inet4_address,
+		   addr->inet4_mask,
+		   addr->inet4_broadcast);
+
+	memcpy(req.ifr_name, dev->name, IFNAMSIZ);
+
+	inaddr = (struct sockaddr_in *)&req.ifr_addr;
+	inaddr->sin_addr.s_addr = ntohl(addr->inet4_address);
+	inaddr->sin_family = AF_INET;
+	ret = __kern_devinet_ioctl(net, SIOCSIFADDR, &req);
+	if (ret < 0) {
+		ckpt_err(ctx, ret, "Failed to set address\n");
+		return ret;
+	}
+
+	inaddr = (struct sockaddr_in *)&req.ifr_addr;
+	inaddr->sin_addr.s_addr = ntohl(addr->inet4_mask);
+	inaddr->sin_family = AF_INET;
+	ret = __kern_devinet_ioctl(net, SIOCSIFNETMASK, &req);
+	if (ret < 0) {
+		ckpt_err(ctx, ret, "Failed to set netmask\n");
+		return ret;
+	}
+
+	inaddr = (struct sockaddr_in *)&req.ifr_addr;
+	inaddr->sin_addr.s_addr = ntohl(addr->inet4_broadcast);
+	inaddr->sin_family = AF_INET;
+	ret = __kern_devinet_ioctl(net, SIOCSIFBRDADDR, &req);
+	if (ret < 0) {
+		ckpt_err(ctx, ret, "Failed to set broadcast\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_IPV6
+static int restore_inet6_addr(struct ckpt_ctx *ctx,
+			      struct net_device *dev,
+			      struct net *net,
+			      struct ckpt_netdev_addr *addr)
+{
+	struct in6_ifreq req;
+	int ret;
+
+	req.ifr6_ifindex = dev->ifindex;
+	NTOH_IPV6(&req.ifr6_addr, &addr->inet6_addr);
+	req.ifr6_prefixlen = addr->inet6_prefix_len;
+
+	ckpt_debug("Restored %s: %pI6\n", dev->name, &req.ifr6_addr);
+
+	ret = __kern_addrconf(net, SIOCSIFADDR, &req);
+	if (ret < 0)
+		ckpt_err(ctx, ret, "Failed to set address");
+
+	return ret;
+}
+#else
+static int restore_inet6_addr(struct ckpt_ctx *ctx,
+			      struct net_device *dev,
+			      struct net *net,
+			      struct ckpt_netdev_addr *addr)
+{
+	ckpt_err(ctx, -ENOSYS, "IPv6 not supported");
+	return -ENOSYS;
+}
+#endif
+
 static int restore_in_addrs(struct ckpt_ctx *ctx,
 			    __u32 naddrs,
 			    struct net *net,
@@ -307,49 +505,17 @@ static int restore_in_addrs(struct ckpt_ctx *ctx,
 
 	for (i = 0; i < naddrs; i++) {
 		struct ckpt_netdev_addr *addr = &addrs[i];
-		struct ifreq req;
-		struct sockaddr_in *inaddr;
 
-		if (addr->type != CKPT_NETDEV_ADDR_IPV4) {
+		if (addr->type == CKPT_NETDEV_ADDR_IPV4)
+			ret = restore_inet4_addr(ctx, dev, net, addr);
+		else if (addr->type == CKPT_NETDEV_ADDR_IPV6)
+			ret = restore_inet6_addr(ctx, dev, net, addr);
+		else {
 			ret = -EINVAL;
 			ckpt_err(ctx, ret, "Unsupported netdev addr type %i\n",
 				 addr->type);
 			break;
 		}
-
-		ckpt_debug("restoring %s: %x/%x/%x\n", dev->name,
-			   addr->inet4_address,
-			   addr->inet4_mask,
-			   addr->inet4_broadcast);
-
-		memcpy(req.ifr_name, dev->name, IFNAMSIZ);
-
-		inaddr = (struct sockaddr_in *)&req.ifr_addr;
-		inaddr->sin_addr.s_addr = ntohl(addr->inet4_address);
-		inaddr->sin_family = AF_INET;
-		ret = __kern_devinet_ioctl(net, SIOCSIFADDR, &req);
-		if (ret < 0) {
-			ckpt_err(ctx, ret, "Failed to set address\n");
-			break;
-		}
-
-		inaddr = (struct sockaddr_in *)&req.ifr_addr;
-		inaddr->sin_addr.s_addr = ntohl(addr->inet4_mask);
-		inaddr->sin_family = AF_INET;
-		ret = __kern_devinet_ioctl(net, SIOCSIFNETMASK, &req);
-		if (ret < 0) {
-			ckpt_err(ctx, ret, "Failed to set netmask\n");
-			break;
-		}
-
-		inaddr = (struct sockaddr_in *)&req.ifr_addr;
-		inaddr->sin_addr.s_addr = ntohl(addr->inet4_broadcast);
-		inaddr->sin_family = AF_INET;
-		ret = __kern_devinet_ioctl(net, SIOCSIFBRDADDR, &req);
-		if (ret < 0) {
-			ckpt_err(ctx, ret, "Failed to set broadcast\n");
-			break;
-		}
 	}
 
  out:
-- 
1.6.2.5

Re: [PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Brian Haley]

Dan Smith wrote:

> +static int ckpt_netdev_inet6_addrs(struct inet6_dev *indev,
> +				   int index, int max,
> +				   struct ckpt_netdev_addr *abuf)
> +{
> +	struct inet6_ifaddr *addr;
> +	struct ifmcaddr6 *mcaddr;
> +	struct ifacaddr6 *acaddr;
> +
> +	for (addr = indev->addr_list; addr; addr = addr->if_next) {
> +		if (ipv6_addr_scope(&addr->addr))
> +			continue; /* Ignore non-global scope addresses */

This will prevent the loopback address (::1) from getting checkpointed
since it's host-local.  The ipv6 module will add it anyways so it's
probably not a big deal.

-Brian

Re: [PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Dan Smith]

BH> This will prevent the loopback address (::1) from getting
BH> checkpointed since it's host-local.  The ipv6 module will add it
BH> anyways so it's probably not a big deal.

Yep, and it does.

Thanks!

-- 
Dan Smith
IBM Linux Technology Center
email: danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org

Re: [PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Oren Laadan]

Dan Smith wrote:
> BH> This will prevent the loopback address (::1) from getting
> BH> checkpointed since it's host-local.  The ipv6 module will add it
> BH> anyways so it's probably not a big deal.
> 
> Yep, and it does.

Probably worth a comment inline ?

Oren.

Re: [PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Serge E. Hallyn]

Quoting Dan Smith (danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):

Two related problems here:

> +#ifdef CONFIG_IPV6

1. this will only trigger if CONFIG_IPV6=y, not if it =m.  So you
might have meant
	#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
or something.  But I'm not sure that if it's a module but not
yet loaded that that suffices?

> +
> +#define __BYTE_ORDER_COPY(op, dst, src)					\
> +	do {								\
> +		int i;							\
> +		for (i = 0; i < 16; i++) {				\
> +			(dst)->in6_u.u6_addr8[i] =			\
> +				(src)->in6_u.u6_addr8[16-i];		\
> +		}							\
> +	} while (0);
> +
> +#define HTON_IPV6(dst, src) __BYTE_ORDER_COPY(htonl, dst, src)
> +#define NTOH_IPV6(dst, src) __BYTE_ORDER_COPY(ntohl, dst, src)
> +
> +static int ckpt_netdev_inet6_addrs(struct inet6_dev *indev,
> +				   int index, int max,
> +				   struct ckpt_netdev_addr *abuf)
> +{
> +	struct inet6_ifaddr *addr;
> +	struct ifmcaddr6 *mcaddr;
> +	struct ifacaddr6 *acaddr;
> +
> +	for (addr = indev->addr_list; addr; addr = addr->if_next) {
> +		if (ipv6_addr_scope(&addr->addr))
> +			continue; /* Ignore non-global scope addresses */
> +
> +		abuf[index].type = CKPT_NETDEV_ADDR_IPV6;
> +
> +		HTON_IPV6(&abuf[index].inet6_addr, &addr->addr);
> +
> +		ckpt_debug("Checkpointed inet6: %pI6\n", &addr->addr);
> +
> +		abuf[index].inet6_prefix_len = addr->prefix_len;
> +		abuf[index].inet6_valid_lft = addr->valid_lft;
> +		abuf[index].inet6_prefered_lft = addr->prefered_lft;
> +		abuf[index].inet6_scope = addr->scope;
> +
> +		if (++index >= max)
> +			return -E2BIG;
> +	}
> +
> +	for (mcaddr = indev->mc_list; mcaddr; mcaddr = mcaddr->next) {
> +		if (ipv6_addr_scope(&mcaddr->mca_addr))
> +			continue; /* Ignore non-global scope addresses */
> +
> +		/* TODO */
> +
> +		/* Multicast addresses are not supported, so do not
> +		 * allow checkpoint to continue if one is assigned
> +		 */
> +		ckpt_debug("ipv6 multicast addresses are not supported\n");
> +		return -EINVAL;
> +	}
> +
> +	for (acaddr = indev->ac_list; acaddr; acaddr = acaddr->aca_next) {
> +		if (ipv6_addr_scope(&acaddr->aca_addr))
> +			continue; /* Ignore non-global scope addresses */
> +
> +		/* TODO */
> +
> +		/* Anycast addresses are not supported, so do not
> +		 * allow checkpoint to continue if one is assigned
> +		 */
> +		ckpt_debug("ipv6 anycast addresses are not supported\n");
> +		return -EINVAL;
> +	}
> +
> +	return index;
> +}
> +#else
> +static int ckpt_netdev_inet6_addrs(struct inet6_dev *indev,
> +				   int index, int max,
> +				   struct ckpt_netdev_addr *abuf)
> +{
> +	return -ENOSYS;
> +}
> +#endif
> +
> +int ckpt_netdev_inet_addrs(struct net_device *dev,
>  			   struct ckpt_netdev_addr *_abuf[])
>  {
>  	struct ckpt_netdev_addr *abuf = NULL;
> -	struct in_ifaddr *addr = indev->ifa_list;
>  	int addrs = 0;
>  	int max = 32;
> 
> @@ -169,21 +288,21 @@ int ckpt_netdev_inet_addrs(struct in_device *indev,
> 
>  	read_lock(&dev_base_lock);
> 
> -	while (addr) {
> -		abuf[addrs].type = CKPT_NETDEV_ADDR_IPV4; /* Only IPv4 now */
> -		abuf[addrs].inet4_local = htonl(addr->ifa_local);
> -		abuf[addrs].inet4_address = htonl(addr->ifa_address);
> -		abuf[addrs].inet4_mask = htonl(addr->ifa_mask);
> -		abuf[addrs].inet4_broadcast = htonl(addr->ifa_broadcast);
> +	addrs = 0;
> 
> -		addr = addr->ifa_next;
> -		if (++addrs >= max) {
> -			read_unlock(&dev_base_lock);
> -			max *= 2;
> -			goto retry;
> -		}
> -	}
> +	addrs = ckpt_netdev_inet4_addrs(dev->ip_ptr, addrs, max, abuf);
> +	if (addrs == -E2BIG) {
> +		read_unlock(&dev_base_lock);
> +		goto retry;
> +	} else if (addrs < 0)
> +		goto unlock;
> 
> +	addrs = ckpt_netdev_inet6_addrs(dev->ip6_ptr, addrs, max, abuf);
> +	if (addrs == -E2BIG) {
> +		read_unlock(&dev_base_lock);
> +		goto retry;
> +	}

This is the second problem.  If CONFIG_IPV6=n or CONFIG_IPV6=m, then
ckpt_netdev_inet6_addrs() will return -ENOSYS, and you'll fail here.
So in those cases there is now no way to do a checkpoint with
CHECKPOINT_NETNS (or without CHECKPOINT_NONETNS :).

The fix of course can't be quite as simple as ignoring return
value of -ENOSYS since you'll have lost the passed-in addrs from
ckpt_netdev_inet4_addrs.

> + unlock:
>  	read_unlock(&dev_base_lock);
>   out:
>  	if (addrs < 0) {

-serge

Re: [PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Dan Smith]

SH> 1. this will only trigger if CONFIG_IPV6=y, not if it =m.  So you
SH> might have meant
SH> 	#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

Ah, okay, right.

>> +	addrs = ckpt_netdev_inet6_addrs(dev->ip6_ptr, addrs, max, abuf);
>> +	if (addrs == -E2BIG) {
>> +		read_unlock(&dev_base_lock);
>> +		goto retry;
>> +	}

SH> This is the second problem.  If CONFIG_IPV6=n or CONFIG_IPV6=m, then
SH> ckpt_netdev_inet6_addrs() will return -ENOSYS, and you'll fail here.
SH> So in those cases there is now no way to do a checkpoint with
SH> CHECKPOINT_NETNS (or without CHECKPOINT_NONETNS :).

SH> The fix of course can't be quite as simple as ignoring return
SH> value of -ENOSYS since you'll have lost the passed-in addrs from
SH> ckpt_netdev_inet4_addrs.

If I change it to compile in with CONFIG_IPV6_MODULE as you stated
above, then it won't return -ENOSYS, right?  The code will still be
there, and will not traverse the ipv6 address list (if I make it check
for an empty dev->ip6_ptr) until the module is loaded and the devices
gain some IPv6 information.

I'll test this and resend the patch appropriately.

Thanks!

-- 
Dan Smith
IBM Linux Technology Center
email: danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org

Re: [PATCH 1/3] C/R: Support for IPv6 addresses on network devices (v2)

[Serge E. Hallyn]

Quoting Dan Smith (danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
> SH> 1. this will only trigger if CONFIG_IPV6=y, not if it =m.  So you
> SH> might have meant
> SH> 	#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
> 
> Ah, okay, right.
> 
> >> +	addrs = ckpt_netdev_inet6_addrs(dev->ip6_ptr, addrs, max, abuf);
> >> +	if (addrs == -E2BIG) {
> >> +		read_unlock(&dev_base_lock);
> >> +		goto retry;
> >> +	}
> 
> SH> This is the second problem.  If CONFIG_IPV6=n or CONFIG_IPV6=m, then
> SH> ckpt_netdev_inet6_addrs() will return -ENOSYS, and you'll fail here.
> SH> So in those cases there is now no way to do a checkpoint with
> SH> CHECKPOINT_NETNS (or without CHECKPOINT_NONETNS :).
> 
> SH> The fix of course can't be quite as simple as ignoring return
> SH> value of -ENOSYS since you'll have lost the passed-in addrs from
> SH> ckpt_netdev_inet4_addrs.
> 
> If I change it to compile in with CONFIG_IPV6_MODULE as you stated
> above, then it won't return -ENOSYS, right?  The code will still be

But it'll return -ENOSYS if CONFIG_IPV6=n.

> there, and will not traverse the ipv6 address list (if I make it check
> for an empty dev->ip6_ptr) until the module is loaded and the devices
> gain some IPv6 information.
> 
> I'll test this and resend the patch appropriately.
> 
> Thanks!
> 
> -- 
> Dan Smith
> IBM Linux Technology Center
> email: danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org
> _______________________________________________
> Containers mailing list
> Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
> https://lists.linux-foundation.org/mailman/listinfo/containers

[PATCH 2/3] C/R: Fix storing IPv6 addresses and handle the "ipv6only" socket flag

[Dan Smith]

The first item is a result of sockaddr_in6 being larger than the base
sockaddr structure, thus not being long enough to reserve enough space in
the checkpoint header.

The second comes into play when things (like sshd) bind to INADDR6_ANY,
set the "ipv6only" socket flag and then bind an IPv4 socket to the same
port.

Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 include/linux/checkpoint_hdr.h |   13 +++++++++++--
 net/ipv4/checkpoint.c          |   34 ++++++++++++++++++++--------------
 net/ipv6/af_inet6.c            |    2 ++
 3 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 90e4934..e771758 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -758,12 +758,21 @@ struct ckpt_hdr_socket_inet {
 		struct in6_addr saddr;
 		struct in6_addr rcv_saddr;
 		struct in6_addr daddr;
+		__u8 ipv6only;
 	} inet6 __attribute__ ((aligned(8)));
 
 	__u32 laddr_len;
 	__u32 raddr_len;
-	struct sockaddr_in laddr;
-	struct sockaddr_in raddr;
+	union {
+		struct sockaddr laddr;
+		struct sockaddr_in laddr4;
+		struct sockaddr_in6 laddr6;
+	};
+	union {
+		struct sockaddr raddr;
+		struct sockaddr_in raddr4;
+		struct sockaddr_in6 raddr6;
+	};
 } __attribute__((aligned(8)));
 
 struct ckpt_hdr_file_socket {
diff --git a/net/ipv4/checkpoint.c b/net/ipv4/checkpoint.c
index b4024e7..57b185d 100644
--- a/net/ipv4/checkpoint.c
+++ b/net/ipv4/checkpoint.c
@@ -190,12 +190,14 @@ static int sock_inet_restore_connection(struct sock *sk,
 	struct inet_sock *inet = inet_sk(sk);
 	int tcp_gso = sk->sk_family == AF_INET ? SKB_GSO_TCPV4 : SKB_GSO_TCPV6;
 
-	inet->inet_daddr = hh->raddr.sin_addr.s_addr;
-	inet->inet_saddr = hh->laddr.sin_addr.s_addr;
-	inet->inet_rcv_saddr = inet->inet_saddr;
+	if (sk->sk_family == AF_INET) {
+		inet->inet_daddr = hh->raddr4.sin_addr.s_addr;
+		inet->inet_saddr = hh->laddr4.sin_addr.s_addr;
+		inet->inet_rcv_saddr = inet->inet_saddr;
 
-	inet->inet_dport = hh->raddr.sin_port;
-	inet->inet_sport = hh->laddr.sin_port;
+		inet->inet_dport = hh->raddr4.sin_port;
+		inet->inet_sport = hh->laddr4.sin_port;
+	}
 
 	if (sk->sk_protocol == IPPROTO_TCP)
 		sk->sk_gso_type = tcp_gso;
@@ -266,6 +268,7 @@ static int sock_inet_cptrst(struct ckpt_ctx *ctx,
 			ipv6_addr_copy(&inet6->rcv_saddr, &hh->inet6.rcv_saddr);
 			ipv6_addr_copy(&inet6->daddr, &hh->inet6.daddr);
 		}
+		CKPT_COPY(op, hh->inet6.ipv6only, inet6->ipv6only);
 	}
 
 	return ret;
@@ -281,8 +284,8 @@ int inet_checkpoint(struct ckpt_ctx *ctx, struct socket *sock)
 		return -EINVAL;
 
 	ret = ckpt_sock_getnames(ctx, sock,
-				(struct sockaddr *)&in->laddr, &in->laddr_len,
-				(struct sockaddr *)&in->raddr, &in->raddr_len);
+				&in->laddr, &in->laddr_len,
+				&in->raddr, &in->raddr_len);
 	if (ret)
 		goto out;
 
@@ -387,19 +390,19 @@ static int inet_precheck(struct socket *sock, struct ckpt_hdr_socket_inet *in)
 	__u8 nonagle_mask = TCP_NAGLE_OFF | TCP_NAGLE_CORK | TCP_NAGLE_PUSH;
 	__u8 ecn_mask = TCP_ECN_OK | TCP_ECN_QUEUE_CWR | TCP_ECN_DEMAND_CWR;
 
-	if ((htons(in->laddr.sin_port) < PROT_SOCK) &&
+	if ((htons(in->laddr4.sin_port) < PROT_SOCK) &&
 	    !capable(CAP_NET_BIND_SERVICE)) {
 		ckpt_debug("unable to bind to port %hu\n",
-			   htons(in->laddr.sin_port));
+			   htons(in->laddr4.sin_port));
 		return -EINVAL;
 	}
 
-	if (in->laddr_len > sizeof(struct sockaddr_in)) {
+	if (in->laddr_len > sizeof(in->laddr6)) {
 		ckpt_debug("laddr_len is too big\n");
 		return -EINVAL;
 	}
 
-	if (in->raddr_len > sizeof(struct sockaddr_in)) {
+	if (in->raddr_len > sizeof(in->laddr6)) {
 		ckpt_debug("raddr_len is too big\n");
 		return -EINVAL;
 	}
@@ -498,13 +501,16 @@ int inet_restore(struct ckpt_ctx *ctx,
 	    ((h->sock.state == TCP_CLOSE) && (in->laddr_len > 0))) {
 		sock->sk->sk_reuse = 2;
 		inet_sk(sock->sk)->freebind = 1;
-		ret = sock->ops->bind(sock,
-				      (struct sockaddr *)&in->laddr,
-				      in->laddr_len);
+		ret = sock->ops->bind(sock, &in->laddr, in->laddr_len);
 		ckpt_debug("inet bind: %i\n", ret);
 		if (ret < 0)
 			goto out;
 
+		if (in->inet6.ipv6only) {
+			struct ipv6_pinfo *np = inet6_sk(sock->sk);
+			np->ipv6only = 1;
+		}
+
 		if (h->sock.state == TCP_LISTEN) {
 			ret = sock->ops->listen(sock, h->sock.backlog);
 			ckpt_debug("inet listen: %i\n", ret);
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 12e69d3..9acb55a 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -523,6 +523,8 @@ const struct proto_ops inet6_stream_ops = {
 	.mmap		   = sock_no_mmap,
 	.sendpage	   = tcp_sendpage,
 	.splice_read	   = tcp_splice_read,
+	.checkpoint	   = inet_checkpoint,
+	.restore	   = inet_restore,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_sock_common_setsockopt,
 	.compat_getsockopt = compat_sock_common_getsockopt,
-- 
1.6.2.5

Re: [PATCH 2/3] C/R: Fix storing IPv6 addresses and handle the "ipv6only" socket flag

[Serge E. Hallyn]

Quoting Dan Smith (danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
> The first item is a result of sockaddr_in6 being larger than the base
> sockaddr structure, thus not being long enough to reserve enough space in
> the checkpoint header.
> 
> The second comes into play when things (like sshd) bind to INADDR6_ANY,
> set the "ipv6only" socket flag and then bind an IPv4 socket to the same
> port.
> 
> Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>

since ipv6 can be a module, this requires:

From 7132840517ecc258a2d972dae7011a6666e91c56 Mon Sep 17 00:00:00 2001
From: Serge E. Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Date: Tue, 6 Apr 2010 12:35:54 -0500
Subject: [PATCH 1/1] export needed symbols needed by ipv6

Signed-off-by: Serge E. Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 net/ipv4/checkpoint.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/checkpoint.c b/net/ipv4/checkpoint.c
index 57b185d..7479ffd 100644
--- a/net/ipv4/checkpoint.c
+++ b/net/ipv4/checkpoint.c
@@ -299,6 +299,7 @@ int inet_checkpoint(struct ckpt_ctx *ctx, struct socket *sock)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(inet_checkpoint);
 
 int inet_collect(struct ckpt_ctx *ctx, struct socket *sock)
 {
@@ -553,3 +554,4 @@ int inet_restore(struct ckpt_ctx *ctx,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(inet_restore);
-- 
1.6.0.6

[PATCH 3/3] Fail checkpoint if IPv4 multicast addresses are configured

[Dan Smith]

This causes checkpoint to fail if an interface actually has a
multicast membership.

Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 net/checkpoint_dev.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/net/checkpoint_dev.c b/net/checkpoint_dev.c
index 776931b..11c6544 100644
--- a/net/checkpoint_dev.c
+++ b/net/checkpoint_dev.c
@@ -17,6 +17,7 @@
 #include <linux/checkpoint.h>
 #include <linux/checkpoint_hdr.h>
 #include <linux/deferqueue.h>
+#include <linux/igmp.h>
 
 #include <net/if_inet6.h>
 #include <net/ipv6.h>
@@ -177,6 +178,7 @@ static int ckpt_netdev_inet4_addrs(struct in_device *indev,
 				   struct ckpt_netdev_addr *abuf)
 {
 	struct in_ifaddr *addr = indev->ifa_list;
+	struct ip_mc_list *mcaddr;
 
 	while (addr) {
 		abuf[index].type = CKPT_NETDEV_ADDR_IPV4;
@@ -190,6 +192,19 @@ static int ckpt_netdev_inet4_addrs(struct in_device *indev,
 			return -E2BIG;
 	}
 
+	for (mcaddr = indev->mc_list; mcaddr; mcaddr = mcaddr->next) {
+		if ((mcaddr->multiaddr & IGMP_LOCAL_GROUP_MASK) == IGMP_LOCAL_GROUP)
+			continue;
+
+		/* TODO */
+
+		/* Multicast addresses are not supported, so do not
+		 * allow checkpoint to continue if one is assigned
+		 */
+		ckpt_debug("ipv4 multicast addresses are not supported\n");
+		return -EINVAL;
+	}
+
 	return index;
 }
 
-- 
1.6.2.5