[PATCHv3 net-next] IPv6: add extack info for IPv6 address add/delete

[PATCHv3 net-next] IPv6: add extack info for IPv6 address add/delete

[Hangbin Liu]

Add extack info for IPv6 address add/delete, which would be useful for
users to understand the problem without having to read kernel code.

Suggested-by: Beniamino Galvani <bgalvani@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
v3: * Update extack message. Pass extack to addrconf_f6i_alloc().
    * Return "IPv6 is disabled" for addrconf_add_dev(), as the same
      with ndisc_allow_add() does.
    * Set dup addr extack message in inet6_rtm_newaddr() instead of
      ipv6_add_addr_hash().
v2: Update extack msg for dead dev. Remove msg for NOBUFS error.
    Add extack for ipv6_add_addr_hash()
---
 include/net/ip6_route.h |  2 +-
 net/ipv6/addrconf.c     | 63 +++++++++++++++++++++++++++++------------
 net/ipv6/anycast.c      |  2 +-
 net/ipv6/route.c        |  5 ++--
 4 files changed, 50 insertions(+), 22 deletions(-)

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 3556595ce59a..b32539bb0fb0 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -156,7 +156,7 @@ void fib6_force_start_gc(struct net *net);
 
 struct fib6_info *addrconf_f6i_alloc(struct net *net, struct inet6_dev *idev,
 				     const struct in6_addr *addr, bool anycast,
-				     gfp_t gfp_flags);
+				     gfp_t gfp_flags, struct netlink_ext_ack *extack);
 
 struct rt6_info *ip6_dst_alloc(struct net *net, struct net_device *dev,
 			       int flags);
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 19eb4b3d26ea..53dea18a4a07 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1068,15 +1068,19 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
 	     !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) ||
 	    (!(idev->dev->flags & IFF_LOOPBACK) &&
 	     !netif_is_l3_master(idev->dev) &&
-	     addr_type & IPV6_ADDR_LOOPBACK))
+	     addr_type & IPV6_ADDR_LOOPBACK)) {
+		NL_SET_ERR_MSG(extack, "Cannot assign requested address");
 		return ERR_PTR(-EADDRNOTAVAIL);
+	}
 
 	if (idev->dead) {
-		err = -ENODEV;			/*XXX*/
+		NL_SET_ERR_MSG(extack, "IPv6 device is going away");
+		err = -ENODEV;
 		goto out;
 	}
 
 	if (idev->cnf.disable_ipv6) {
+		NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
 		err = -EACCES;
 		goto out;
 	}
@@ -1103,7 +1107,7 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
 		goto out;
 	}
 
-	f6i = addrconf_f6i_alloc(net, idev, cfg->pfx, false, gfp_flags);
+	f6i = addrconf_f6i_alloc(net, idev, cfg->pfx, false, gfp_flags, extack);
 	if (IS_ERR(f6i)) {
 		err = PTR_ERR(f6i);
 		f6i = NULL;
@@ -2921,30 +2925,40 @@ static int inet6_addr_add(struct net *net, int ifindex,
 
 	ASSERT_RTNL();
 
-	if (cfg->plen > 128)
+	if (cfg->plen > 128) {
+		NL_SET_ERR_MSG(extack, "Invalid prefix length");
 		return -EINVAL;
+	}
 
 	/* check the lifetime */
-	if (!cfg->valid_lft || cfg->preferred_lft > cfg->valid_lft)
+	if (!cfg->valid_lft || cfg->preferred_lft > cfg->valid_lft) {
+		NL_SET_ERR_MSG(extack, "IPv6 address lifetime invalid");
 		return -EINVAL;
+	}
 
-	if (cfg->ifa_flags & IFA_F_MANAGETEMPADDR && cfg->plen != 64)
+	if (cfg->ifa_flags & IFA_F_MANAGETEMPADDR && cfg->plen != 64) {
+		NL_SET_ERR_MSG(extack, "IPv6 address with \"mngtmpaddr\" flag must have a prefix length of 64");
 		return -EINVAL;
+	}
 
 	dev = __dev_get_by_index(net, ifindex);
 	if (!dev)
 		return -ENODEV;
 
 	idev = addrconf_add_dev(dev);
-	if (IS_ERR(idev))
+	if (IS_ERR(idev)) {
+		NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
 		return PTR_ERR(idev);
+	}
 
 	if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
 		int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
 					 true, cfg->pfx, ifindex);
 
-		if (ret < 0)
+		if (ret < 0) {
+			NL_SET_ERR_MSG(extack, "Multicast auto join failed");
 			return ret;
+		}
 	}
 
 	cfg->scope = ipv6_addr_scope(cfg->pfx);
@@ -3001,22 +3015,29 @@ static int inet6_addr_add(struct net *net, int ifindex,
 }
 
 static int inet6_addr_del(struct net *net, int ifindex, u32 ifa_flags,
-			  const struct in6_addr *pfx, unsigned int plen)
+			  const struct in6_addr *pfx, unsigned int plen,
+			  struct netlink_ext_ack *extack)
 {
 	struct inet6_ifaddr *ifp;
 	struct inet6_dev *idev;
 	struct net_device *dev;
 
-	if (plen > 128)
+	if (plen > 128) {
+		NL_SET_ERR_MSG(extack, "Invalid prefix length");
 		return -EINVAL;
+	}
 
 	dev = __dev_get_by_index(net, ifindex);
-	if (!dev)
+	if (!dev) {
+		NL_SET_ERR_MSG(extack, "Unable to find the interface");
 		return -ENODEV;
+	}
 
 	idev = __in6_dev_get(dev);
-	if (!idev)
+	if (!idev) {
+		NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
 		return -ENXIO;
+	}
 
 	read_lock_bh(&idev->lock);
 	list_for_each_entry(ifp, &idev->addr_list, if_list) {
@@ -3039,6 +3060,8 @@ static int inet6_addr_del(struct net *net, int ifindex, u32 ifa_flags,
 		}
 	}
 	read_unlock_bh(&idev->lock);
+
+	NL_SET_ERR_MSG(extack, "IPv6 address not found");
 	return -EADDRNOTAVAIL;
 }
 
@@ -3081,7 +3104,7 @@ int addrconf_del_ifaddr(struct net *net, void __user *arg)
 
 	rtnl_lock();
 	err = inet6_addr_del(net, ireq.ifr6_ifindex, 0, &ireq.ifr6_addr,
-			     ireq.ifr6_prefixlen);
+			     ireq.ifr6_prefixlen, NULL);
 	rtnl_unlock();
 	return err;
 }
@@ -3484,7 +3507,7 @@ static int fixup_permanent_addr(struct net *net,
 		struct fib6_info *f6i, *prev;
 
 		f6i = addrconf_f6i_alloc(net, idev, &ifp->addr, false,
-					 GFP_ATOMIC);
+					 GFP_ATOMIC, NULL);
 		if (IS_ERR(f6i))
 			return PTR_ERR(f6i);
 
@@ -4694,7 +4717,7 @@ inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifa_flags &= IFA_F_MANAGETEMPADDR;
 
 	return inet6_addr_del(net, ifm->ifa_index, ifa_flags, pfx,
-			      ifm->ifa_prefixlen);
+			      ifm->ifa_prefixlen, extack);
 }
 
 static int modify_prefix_route(struct inet6_ifaddr *ifp,
@@ -4899,8 +4922,10 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 	}
 
 	dev =  __dev_get_by_index(net, ifm->ifa_index);
-	if (!dev)
+	if (!dev) {
+		NL_SET_ERR_MSG(extack, "Unable to find the interface");
 		return -ENODEV;
+	}
 
 	if (tb[IFA_FLAGS])
 		cfg.ifa_flags = nla_get_u32(tb[IFA_FLAGS]);
@@ -4935,10 +4960,12 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 	}
 
 	if (nlh->nlmsg_flags & NLM_F_EXCL ||
-	    !(nlh->nlmsg_flags & NLM_F_REPLACE))
+	    !(nlh->nlmsg_flags & NLM_F_REPLACE)) {
+		NL_SET_ERR_MSG(extack, "IPv6 address already assigned");
 		err = -EEXIST;
-	else
+	} else {
 		err = inet6_addr_modify(net, ifa, &cfg);
+	}
 
 	in6_ifa_put(ifa);
 
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index dacdea7fcb62..bb17f484ee2c 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -305,7 +305,7 @@ int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
 	}
 
 	net = dev_net(idev->dev);
-	f6i = addrconf_f6i_alloc(net, idev, addr, true, GFP_ATOMIC);
+	f6i = addrconf_f6i_alloc(net, idev, addr, true, GFP_ATOMIC, NULL);
 	if (IS_ERR(f6i)) {
 		err = PTR_ERR(f6i);
 		goto out;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 64e873f5895f..c90700aed3a1 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4543,7 +4543,8 @@ static int ip6_pkt_prohibit_out(struct net *net, struct sock *sk, struct sk_buff
 struct fib6_info *addrconf_f6i_alloc(struct net *net,
 				     struct inet6_dev *idev,
 				     const struct in6_addr *addr,
-				     bool anycast, gfp_t gfp_flags)
+				     bool anycast, gfp_t gfp_flags,
+				     struct netlink_ext_ack *extack)
 {
 	struct fib6_config cfg = {
 		.fc_table = l3mdev_fib_table(idev->dev) ? : RT6_TABLE_LOCAL,
@@ -4565,7 +4566,7 @@ struct fib6_info *addrconf_f6i_alloc(struct net *net,
 		cfg.fc_flags |= RTF_LOCAL;
 	}
 
-	f6i = ip6_route_info_create(&cfg, gfp_flags, NULL);
+	f6i = ip6_route_info_create(&cfg, gfp_flags, extack);
 	if (!IS_ERR(f6i)) {
 		f6i->dst_nocount = true;
 
-- 
2.38.1

Re: [PATCHv3 net-next] IPv6: add extack info for IPv6 address add/delete

[David Ahern]

On 7/24/23 1:50 AM, Hangbin Liu wrote:
> Add extack info for IPv6 address add/delete, which would be useful for
> users to understand the problem without having to read kernel code.
> 
> Suggested-by: Beniamino Galvani <bgalvani@redhat.com>
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
> v3: * Update extack message. Pass extack to addrconf_f6i_alloc().
>     * Return "IPv6 is disabled" for addrconf_add_dev(), as the same
>       with ndisc_allow_add() does.
>     * Set dup addr extack message in inet6_rtm_newaddr() instead of
>       ipv6_add_addr_hash().
> v2: Update extack msg for dead dev. Remove msg for NOBUFS error.
>     Add extack for ipv6_add_addr_hash()
> ---
>  include/net/ip6_route.h |  2 +-
>  net/ipv6/addrconf.c     | 63 +++++++++++++++++++++++++++++------------
>  net/ipv6/anycast.c      |  2 +-
>  net/ipv6/route.c        |  5 ++--
>  4 files changed, 50 insertions(+), 22 deletions(-)
> 

This patch is getting long enough, so:
Reviewed-by: David Ahern <dsahern@kernel.org>

Followup requests below. Thanks,

> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 19eb4b3d26ea..53dea18a4a07 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -1068,15 +1068,19 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
>  	     !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) ||
>  	    (!(idev->dev->flags & IFF_LOOPBACK) &&
>  	     !netif_is_l3_master(idev->dev) &&
> -	     addr_type & IPV6_ADDR_LOOPBACK))
> +	     addr_type & IPV6_ADDR_LOOPBACK)) {
> +		NL_SET_ERR_MSG(extack, "Cannot assign requested address");
>  		return ERR_PTR(-EADDRNOTAVAIL);
> +	}

It would be good to split the above checks into separate ones with more
specific messages.

>  
>  	if (idev->dead) {
> -		err = -ENODEV;			/*XXX*/
> +		NL_SET_ERR_MSG(extack, "IPv6 device is going away");
> +		err = -ENODEV;
>  		goto out;
>  	}
>  
>  	if (idev->cnf.disable_ipv6) {
> +		NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
>  		err = -EACCES;
>  		goto out;
>  	}

...

>  
>  	if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
>  		int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
>  					 true, cfg->pfx, ifindex);

and pass extack to this one for better message as well.

>  
> -		if (ret < 0)
> +		if (ret < 0) {
> +			NL_SET_ERR_MSG(extack, "Multicast auto join failed");
>  			return ret;
> +		}
>  	}
>  
>  	cfg->scope = ipv6_addr_scope(cfg->pfx);

Re: [PATCHv3 net-next] IPv6: add extack info for IPv6 address add/delete

[Hangbin Liu]

On Mon, Jul 24, 2023 at 09:02:42AM -0600, David Ahern wrote:
> On 7/24/23 1:50 AM, Hangbin Liu wrote:
> > Add extack info for IPv6 address add/delete, which would be useful for
> > users to understand the problem without having to read kernel code.
> > 
> > Suggested-by: Beniamino Galvani <bgalvani@redhat.com>
> > Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> > ---
> > v3: * Update extack message. Pass extack to addrconf_f6i_alloc().
> >     * Return "IPv6 is disabled" for addrconf_add_dev(), as the same
> >       with ndisc_allow_add() does.
> >     * Set dup addr extack message in inet6_rtm_newaddr() instead of
> >       ipv6_add_addr_hash().
> > v2: Update extack msg for dead dev. Remove msg for NOBUFS error.
> >     Add extack for ipv6_add_addr_hash()
> > ---
> >  include/net/ip6_route.h |  2 +-
> >  net/ipv6/addrconf.c     | 63 +++++++++++++++++++++++++++++------------
> >  net/ipv6/anycast.c      |  2 +-
> >  net/ipv6/route.c        |  5 ++--
> >  4 files changed, 50 insertions(+), 22 deletions(-)
> > 
> 
> This patch is getting long enough, so:
> Reviewed-by: David Ahern <dsahern@kernel.org>
> 

Thanks a lot for your review.

> Followup requests below. Thanks,

> 
> > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> > index 19eb4b3d26ea..53dea18a4a07 100644
> > --- a/net/ipv6/addrconf.c
> > +++ b/net/ipv6/addrconf.c
> > @@ -1068,15 +1068,19 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
> >  	     !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) ||
> >  	    (!(idev->dev->flags & IFF_LOOPBACK) &&
> >  	     !netif_is_l3_master(idev->dev) &&
> > -	     addr_type & IPV6_ADDR_LOOPBACK))
> > +	     addr_type & IPV6_ADDR_LOOPBACK)) {
> > +		NL_SET_ERR_MSG(extack, "Cannot assign requested address");
> >  		return ERR_PTR(-EADDRNOTAVAIL);
> > +	}
> 
> It would be good to split the above checks into separate ones with more
> specific messages.

How about this.

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 53dea18a4a07..e6c3fe413441 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1063,13 +1063,17 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
        struct fib6_info *f6i = NULL;
        int err = 0;

-       if (addr_type == IPV6_ADDR_ANY ||
-           (addr_type & IPV6_ADDR_MULTICAST &&
-            !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) ||
-           (!(idev->dev->flags & IFF_LOOPBACK) &&
-            !netif_is_l3_master(idev->dev) &&
-            addr_type & IPV6_ADDR_LOOPBACK)) {
-               NL_SET_ERR_MSG(extack, "Cannot assign requested address");
+       if (addr_type == IPV6_ADDR_ANY) {
+               NL_SET_ERR_MSG(extack, "IPv6: Cannot assign unspecified address");
+               return ERR_PTR(-EADDRNOTAVAIL);
+       } else if (addr_type & IPV6_ADDR_MULTICAST &&
+                  !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) {
+               NL_SET_ERR_MSG(extack, "IPv6: Cannot assign multicast address without \"IFA_F_MCAUTOJOIN\" flag");
+               return ERR_PTR(-EADDRNOTAVAIL);
+       } else if (!(idev->dev->flags & IFF_LOOPBACK) &&
+                  !netif_is_l3_master(idev->dev) &&
+                  addr_type & IPV6_ADDR_LOOPBACK) {
+               NL_SET_ERR_MSG(extack, "IPv6: Cannot assign loopback address on this device");
                return ERR_PTR(-EADDRNOTAVAIL);
        }

> ...
> 
> >  
> >  	if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
> >  		int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
> >  					 true, cfg->pfx, ifindex);
> 
> and pass extack to this one for better message as well.

This one looks a little deep. We need pass extack to
- ipv6_mc_config
  - ipv6_sock_mc_join
    - __ipv6_sock_mc_join
      - __ipv6_dev_mc_inc	maybe also this one??

to get more detailed message. And all these are "Join multicast group failed".
Do you still want to do this?

Thanks
Hangbin

> 
> >  
> > -		if (ret < 0)
> > +		if (ret < 0) {
> > +			NL_SET_ERR_MSG(extack, "Multicast auto join failed");
> >  			return ret;
> > +		}
> >  	}
> >  
> >  	cfg->scope = ipv6_addr_scope(cfg->pfx);
> 
> 

Re: [PATCHv3 net-next] IPv6: add extack info for IPv6 address add/delete

[Ido Schimmel]

On Mon, Jul 24, 2023 at 03:50:51PM +0800, Hangbin Liu wrote:
> Add extack info for IPv6 address add/delete, which would be useful for
> users to understand the problem without having to read kernel code.
> 
> Suggested-by: Beniamino Galvani <bgalvani@redhat.com>
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

Re: [PATCHv3 net-next] IPv6: add extack info for IPv6 address add/delete

[David Ahern]

On 7/25/23 1:45 AM, Hangbin Liu wrote:
>>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>>> index 19eb4b3d26ea..53dea18a4a07 100644
>>> --- a/net/ipv6/addrconf.c
>>> +++ b/net/ipv6/addrconf.c
>>> @@ -1068,15 +1068,19 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
>>>  	     !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) ||
>>>  	    (!(idev->dev->flags & IFF_LOOPBACK) &&
>>>  	     !netif_is_l3_master(idev->dev) &&
>>> -	     addr_type & IPV6_ADDR_LOOPBACK))
>>> +	     addr_type & IPV6_ADDR_LOOPBACK)) {
>>> +		NL_SET_ERR_MSG(extack, "Cannot assign requested address");
>>>  		return ERR_PTR(-EADDRNOTAVAIL);
>>> +	}
>>
>> It would be good to split the above checks into separate ones with more
>> specific messages.
> 
> How about this.
> 
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 53dea18a4a07..e6c3fe413441 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -1063,13 +1063,17 @@ ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
>         struct fib6_info *f6i = NULL;
>         int err = 0;
> 
> -       if (addr_type == IPV6_ADDR_ANY ||
> -           (addr_type & IPV6_ADDR_MULTICAST &&
> -            !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) ||
> -           (!(idev->dev->flags & IFF_LOOPBACK) &&
> -            !netif_is_l3_master(idev->dev) &&
> -            addr_type & IPV6_ADDR_LOOPBACK)) {
> -               NL_SET_ERR_MSG(extack, "Cannot assign requested address");
> +       if (addr_type == IPV6_ADDR_ANY) {
> +               NL_SET_ERR_MSG(extack, "IPv6: Cannot assign unspecified address");

Maybe just "IPv6: Invalid address".

Also, that reminds me that IPv6 should be using NL_SET_ERR_MSG_MOD which
will add the IPv6 part.



> +               return ERR_PTR(-EADDRNOTAVAIL);
> +       } else if (addr_type & IPV6_ADDR_MULTICAST &&
> +                  !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) {
> +               NL_SET_ERR_MSG(extack, "IPv6: Cannot assign multicast address without \"IFA_F_MCAUTOJOIN\" flag");
> +               return ERR_PTR(-EADDRNOTAVAIL);
> +       } else if (!(idev->dev->flags & IFF_LOOPBACK) &&
> +                  !netif_is_l3_master(idev->dev) &&
> +                  addr_type & IPV6_ADDR_LOOPBACK) {
> +               NL_SET_ERR_MSG(extack, "IPv6: Cannot assign loopback address on this device");
>                 return ERR_PTR(-EADDRNOTAVAIL);
>         }
> 
>> ...
>>
>>>  
>>>  	if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
>>>  		int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
>>>  					 true, cfg->pfx, ifindex);
>>
>> and pass extack to this one for better message as well.
> 
> This one looks a little deep. We need pass extack to
> - ipv6_mc_config
>   - ipv6_sock_mc_join
>     - __ipv6_sock_mc_join
>       - __ipv6_dev_mc_inc	maybe also this one??
> 
> to get more detailed message. And all these are "Join multicast group failed".
> Do you still want to do this?

ok, staring at the errors for that stack, not much value I guess.