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[net-next,V8] net: Variable SLAAC: SLAAC with prefixes of arbitrary length in PIO

Message ID 176458a838e.100a4c464143350.2864106687411861504@shytyi.net (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series [net-next,V8] net: Variable SLAAC: SLAAC with prefixes of arbitrary length in PIO | expand

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Commit Message

Dmytro Shytyi Dec. 9, 2020, 3:27 a.m. UTC 
Variable SLAAC [Can be activated via sysctl]: 
SLAAC with prefixes of arbitrary length in PIO (randomly
generated hostID or stable privacy + privacy extensions).
The main problem is that SLAAC RA or PD allocates a /64 by the Wireless
carrier 4G, 5G to a mobile hotspot, however segmentation of the /64 via
SLAAC is required so that downstream interfaces can be further subnetted.
Example: uCPE device (4G + WI-FI enabled) receives /64 via Wireless, and
assigns /72 to VNF-Firewall, /72 to WIFI, /72 to VNF-Router, /72 to
Load-Balancer and /72 to wired connected devices.
IETF document that defines problem statement:
draft-mishra-v6ops-variable-slaac-problem-stmt
IETF document that specifies variable slaac:
draft-mishra-6man-variable-slaac

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---

Comments

David Miller Dec. 16, 2020, midnight UTC | #1 
From: Dmytro Shytyi <dmytro@shytyi.net>
Date: Wed, 09 Dec 2020 04:27:54 +0100

> Variable SLAAC [Can be activated via sysctl]: 
> SLAAC with prefixes of arbitrary length in PIO (randomly
> generated hostID or stable privacy + privacy extensions).
> The main problem is that SLAAC RA or PD allocates a /64 by the Wireless
> carrier 4G, 5G to a mobile hotspot, however segmentation of the /64 via
> SLAAC is required so that downstream interfaces can be further subnetted.
> Example: uCPE device (4G + WI-FI enabled) receives /64 via Wireless, and
> assigns /72 to VNF-Firewall, /72 to WIFI, /72 to VNF-Router, /72 to
> Load-Balancer and /72 to wired connected devices.
> IETF document that defines problem statement:
> draft-mishra-v6ops-variable-slaac-problem-stmt
> IETF document that specifies variable slaac:
> draft-mishra-6man-variable-slaac
> 
> Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
> ---
> diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
> index dda61d150a13..67ca3925463c 100644
> --- a/include/linux/ipv6.h
> +++ b/include/linux/ipv6.h
> @@ -75,6 +75,7 @@ struct ipv6_devconf {
>  	__s32		disable_policy;
>  	__s32           ndisc_tclass;
>  	__s32		rpl_seg_enabled;
> +	__s32		variable_slaac;
>  
>  	struct ctl_table_header *sysctl_header;
>  };
> diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
> index 13e8751bf24a..f2af4f9fba2d 100644
> --- a/include/uapi/linux/ipv6.h
> +++ b/include/uapi/linux/ipv6.h
> @@ -189,7 +189,8 @@ enum {
>  	DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN,
>  	DEVCONF_NDISC_TCLASS,
>  	DEVCONF_RPL_SEG_ENABLED,
> -	DEVCONF_MAX
> +	DEVCONF_MAX,
> +	DEVCONF_VARIABLE_SLAAC
>  };
>  
>  
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index eff2cacd5209..07afe4ce984e 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -236,6 +236,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
>  	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
>  	.disable_policy		= 0,
>  	.rpl_seg_enabled	= 0,
> +	.variable_slaac		= 0,
>  };
>  
>  static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
> @@ -291,6 +292,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
>  	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
>  	.disable_policy		= 0,
>  	.rpl_seg_enabled	= 0,
> +	.variable_slaac		= 0,
>  };
>  
>  /* Check if link is ready: is it up and is a valid qdisc available */
> @@ -1340,9 +1342,15 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
>  		goto out;
>  	}
>  	in6_ifa_hold(ifp);
> -	memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
> -	ipv6_gen_rnd_iid(&addr);
>  
> +	if (ifp->prefix_len == 64) {
> +		memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
> +		ipv6_gen_rnd_iid(&addr);
> +	} else if (ifp->prefix_len > 0 && ifp->prefix_len <= 128 &&
> +		   idev->cnf.variable_slaac) {
> +		get_random_bytes(addr.s6_addr, 16);
> +		ipv6_addr_prefix_copy(&addr, &ifp->addr, ifp->prefix_len);
> +	}
>  	age = (now - ifp->tstamp) / HZ;
>  
>  	regen_advance = idev->cnf.regen_max_retry *
> @@ -2569,6 +2577,37 @@ static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
>  	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
>  }
>  
> +static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp,
> +						      struct inet6_dev *in6_dev,
> +						      struct net *net,
> +						      const struct prefix_info *pinfo)
> +{
> +	struct inet6_ifaddr *result_base = NULL;
> +	struct inet6_ifaddr *result = NULL;
> +	bool prfxs_equal;
> +
> +	result_base = result;

This is NULL, are you sure you didn't mewan to init this to 'ifp'
 or similar instead?

Thanks.
Dmytro Shytyi Dec. 16, 2020, 2:01 p.m. UTC | #2 
Hello David,

Thank you for your comment. 
Asnwers in-line.

Take care,
                              
Dmytro SHYTYI


---- On Wed, 16 Dec 2020 01:00:49 +0100 David Miller <davem@davemloft.net> wrote ----

 > From: Dmytro Shytyi <dmytro@shytyi.net> 
 > Date: Wed, 09 Dec 2020 04:27:54 +0100 
 >  
 > > Variable SLAAC [Can be activated via sysctl]: 
 > > SLAAC with prefixes of arbitrary length in PIO (randomly 
 > > generated hostID or stable privacy + privacy extensions). 
 > > The main problem is that SLAAC RA or PD allocates a /64 by the Wireless 
 > > carrier 4G, 5G to a mobile hotspot, however segmentation of the /64 via 
 > > SLAAC is required so that downstream interfaces can be further subnetted. 
 > > Example: uCPE device (4G + WI-FI enabled) receives /64 via Wireless, and 
 > > assigns /72 to VNF-Firewall, /72 to WIFI, /72 to VNF-Router, /72 to 
 > > Load-Balancer and /72 to wired connected devices. 
 > > IETF document that defines problem statement: 
 > > draft-mishra-v6ops-variable-slaac-problem-stmt 
 > > IETF document that specifies variable slaac: 
 > > draft-mishra-6man-variable-slaac 
 > > 
 > > Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net> 
 > > --- 
 > > diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h 
 > > index dda61d150a13..67ca3925463c 100644 
 > > --- a/include/linux/ipv6.h 
 > > +++ b/include/linux/ipv6.h 
 > > @@ -75,6 +75,7 @@ struct ipv6_devconf { 
 > >      __s32        disable_policy; 
 > >      __s32           ndisc_tclass; 
 > >      __s32        rpl_seg_enabled; 
 > > +    __s32        variable_slaac; 
 > > 
 > >      struct ctl_table_header *sysctl_header; 
 > >  }; 
 > > diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h 
 > > index 13e8751bf24a..f2af4f9fba2d 100644 
 > > --- a/include/uapi/linux/ipv6.h 
 > > +++ b/include/uapi/linux/ipv6.h 
 > > @@ -189,7 +189,8 @@ enum { 
 > >      DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, 
 > >      DEVCONF_NDISC_TCLASS, 
 > >      DEVCONF_RPL_SEG_ENABLED, 
 > > -    DEVCONF_MAX 
 > > +    DEVCONF_MAX, 
 > > +    DEVCONF_VARIABLE_SLAAC 
 > >  }; 
 > > 
 > > 
 > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c 
 > > index eff2cacd5209..07afe4ce984e 100644 
 > > --- a/net/ipv6/addrconf.c 
 > > +++ b/net/ipv6/addrconf.c 
 > > @@ -236,6 +236,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { 
 > >      .addr_gen_mode        = IN6_ADDR_GEN_MODE_EUI64, 
 > >      .disable_policy        = 0, 
 > >      .rpl_seg_enabled    = 0, 
 > > +    .variable_slaac        = 0, 
 > >  }; 
 > > 
 > >  static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { 
 > > @@ -291,6 +292,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { 
 > >      .addr_gen_mode        = IN6_ADDR_GEN_MODE_EUI64, 
 > >      .disable_policy        = 0, 
 > >      .rpl_seg_enabled    = 0, 
 > > +    .variable_slaac        = 0, 
 > >  }; 
 > > 
 > >  /* Check if link is ready: is it up and is a valid qdisc available */ 
 > > @@ -1340,9 +1342,15 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) 
 > >          goto out; 
 > >      } 
 > >      in6_ifa_hold(ifp); 
 > > -    memcpy(addr.s6_addr, ifp->addr.s6_addr, 8); 
 > > -    ipv6_gen_rnd_iid(&addr); 
 > > 
 > > +    if (ifp->prefix_len == 64) { 
 > > +        memcpy(addr.s6_addr, ifp->addr.s6_addr, 8); 
 > > +        ipv6_gen_rnd_iid(&addr); 
 > > +    } else if (ifp->prefix_len > 0 && ifp->prefix_len <= 128 && 
 > > +           idev->cnf.variable_slaac) { 
 > > +        get_random_bytes(addr.s6_addr, 16); 
 > > +        ipv6_addr_prefix_copy(&addr, &ifp->addr, ifp->prefix_len); 
 > > +    } 
 > >      age = (now - ifp->tstamp) / HZ; 
 > > 
 > >      regen_advance = idev->cnf.regen_max_retry * 
 > > @@ -2569,6 +2577,37 @@ static bool is_addr_mode_generate_stable(struct inet6_dev *idev) 
 > >             idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM; 
 > >  } 
 > > 
 > > +static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp, 
 > > +                              struct inet6_dev *in6_dev, 
 > > +                              struct net *net, 
 > > +                              const struct prefix_info *pinfo) 
 > > +{ 
 > > +    struct inet6_ifaddr *result_base = NULL; 
 > > +    struct inet6_ifaddr *result = NULL; 
 > > +    bool prfxs_equal; 
 > > + 
 > > +    result_base = result; 
 >  
 > This is NULL, are you sure you didn't mewan to init this to 'ifp' 
 >  or similar instead? 

[Dmytro] I put the entire function to comment below the instructions.
[Dmytro]:
+static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp,
+                         struct inet6_dev *in6_dev,
+                         struct net *net,
+                         const struct prefix_info *pinfo)
+{
+    struct inet6_ifaddr *result_base = NULL;
+    struct inet6_ifaddr *result = NULL;
+    bool prfxs_equal;
+
+    result_base = result;
+    rcu_read_lock();
+    list_for_each_entry_rcu(ifp, &in6_dev->addr_list, if_list) {
+        if (!net_eq(dev_net(ifp->idev->dev), net))
+            continue;
+        prfxs_equal =
+            ipv6_prefix_equal(&pinfo->prefix, &ifp->addr, pinfo->prefix_len);
+        if (prfxs_equal && pinfo->prefix_len == ifp->prefix_len) {
+            result = ifp;
+            in6_ifa_hold(ifp);
+            break;
+        }
+    }
+    rcu_read_unlock();
+    if (result_base != result)
+        ifp = result;
+    else
+        ifp = NULL;
+
+    return ifp;
+}
+

[Dmytro]:
1st initial stage is :
+    result_base = result;

2nd stage is (as you mention, 'result' will be assigned to 'ifp', in the process):
+            result = ifp;

3rd stage is to compare if  "result_base" and "result" are not equal (and take required action).
 if (result_base != result)
+        ifp = result;
+    else
+        ifp = NULL;

Looks more/less ok for me.

Thanks.

 > Thanks. 
 >
Jakub Kicinski Dec. 16, 2020, 5:28 p.m. UTC | #3 
On Wed, 16 Dec 2020 15:01:33 +0100 Dmytro Shytyi wrote:
> Hello David,
> 
> Thank you for your comment. 
> Asnwers in-line.
> 
> Take care,
>                               
> Dmytro SHYTYI
> 
> 
> ---- On Wed, 16 Dec 2020 01:00:49 +0100 David Miller <davem@davemloft.net> wrote ----
> 
>  > From: Dmytro Shytyi <dmytro@shytyi.net> 
>  > Date: Wed, 09 Dec 2020 04:27:54 +0100 
>  >    
>  > > Variable SLAAC [Can be activated via sysctl]: 
>  > > SLAAC with prefixes of arbitrary length in PIO (randomly 
>  > > generated hostID or stable privacy + privacy extensions). 
>  > > The main problem is that SLAAC RA or PD allocates a /64 by the Wireless 
>  > > carrier 4G, 5G to a mobile hotspot, however segmentation of the /64 via 
>  > > SLAAC is required so that downstream interfaces can be further subnetted. 
>  > > Example: uCPE device (4G + WI-FI enabled) receives /64 via Wireless, and 
>  > > assigns /72 to VNF-Firewall, /72 to WIFI, /72 to VNF-Router, /72 to 
>  > > Load-Balancer and /72 to wired connected devices. 
>  > > IETF document that defines problem statement: 
>  > > draft-mishra-v6ops-variable-slaac-problem-stmt 
>  > > IETF document that specifies variable slaac: 
>  > > draft-mishra-6man-variable-slaac 
>  > > 
>  > > Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net> 
>  > > --- 
>  > > diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h 
>  > > index dda61d150a13..67ca3925463c 100644 
>  > > --- a/include/linux/ipv6.h 
>  > > +++ b/include/linux/ipv6.h 
>  > > @@ -75,6 +75,7 @@ struct ipv6_devconf { 
>  > >      __s32        disable_policy; 
>  > >      __s32           ndisc_tclass; 
>  > >      __s32        rpl_seg_enabled; 
>  > > +    __s32        variable_slaac; 
>  > > 
>  > >      struct ctl_table_header *sysctl_header; 
>  > >  }; 
>  > > diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h 
>  > > index 13e8751bf24a..f2af4f9fba2d 100644 
>  > > --- a/include/uapi/linux/ipv6.h 
>  > > +++ b/include/uapi/linux/ipv6.h 
>  > > @@ -189,7 +189,8 @@ enum { 
>  > >      DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, 
>  > >      DEVCONF_NDISC_TCLASS, 
>  > >      DEVCONF_RPL_SEG_ENABLED, 
>  > > -    DEVCONF_MAX 
>  > > +    DEVCONF_MAX, 
>  > > +    DEVCONF_VARIABLE_SLAAC 
>  > >  }; 
>  > > 
>  > > 
>  > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c 
>  > > index eff2cacd5209..07afe4ce984e 100644 
>  > > --- a/net/ipv6/addrconf.c 
>  > > +++ b/net/ipv6/addrconf.c 
>  > > @@ -236,6 +236,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { 
>  > >      .addr_gen_mode        = IN6_ADDR_GEN_MODE_EUI64, 
>  > >      .disable_policy        = 0, 
>  > >      .rpl_seg_enabled    = 0, 
>  > > +    .variable_slaac        = 0, 
>  > >  }; 
>  > > 
>  > >  static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { 
>  > > @@ -291,6 +292,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { 
>  > >      .addr_gen_mode        = IN6_ADDR_GEN_MODE_EUI64, 
>  > >      .disable_policy        = 0, 
>  > >      .rpl_seg_enabled    = 0, 
>  > > +    .variable_slaac        = 0, 
>  > >  }; 
>  > > 
>  > >  /* Check if link is ready: is it up and is a valid qdisc available */ 
>  > > @@ -1340,9 +1342,15 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) 
>  > >          goto out; 
>  > >      } 
>  > >      in6_ifa_hold(ifp); 
>  > > -    memcpy(addr.s6_addr, ifp->addr.s6_addr, 8); 
>  > > -    ipv6_gen_rnd_iid(&addr); 
>  > > 
>  > > +    if (ifp->prefix_len == 64) { 
>  > > +        memcpy(addr.s6_addr, ifp->addr.s6_addr, 8); 
>  > > +        ipv6_gen_rnd_iid(&addr); 
>  > > +    } else if (ifp->prefix_len > 0 && ifp->prefix_len <= 128 && 
>  > > +           idev->cnf.variable_slaac) { 
>  > > +        get_random_bytes(addr.s6_addr, 16); 
>  > > +        ipv6_addr_prefix_copy(&addr, &ifp->addr, ifp->prefix_len); 
>  > > +    } 
>  > >      age = (now - ifp->tstamp) / HZ; 
>  > > 
>  > >      regen_advance = idev->cnf.regen_max_retry * 
>  > > @@ -2569,6 +2577,37 @@ static bool is_addr_mode_generate_stable(struct inet6_dev *idev) 
>  > >             idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM; 
>  > >  } 
>  > > 
>  > > +static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp, 
>  > > +                              struct inet6_dev *in6_dev, 
>  > > +                              struct net *net, 
>  > > +                              const struct prefix_info *pinfo) 
>  > > +{ 
>  > > +    struct inet6_ifaddr *result_base = NULL; 
>  > > +    struct inet6_ifaddr *result = NULL; 
>  > > +    bool prfxs_equal; 
>  > > + 
>  > > +    result_base = result;   
>  >  
>  > This is NULL, are you sure you didn't mewan to init this to 'ifp' 
>  >  or similar instead?   
> 
> [Dmytro] I put the entire function to comment below the instructions.
> [Dmytro]:
> +static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp,
> +                         struct inet6_dev *in6_dev,
> +                         struct net *net,
> +                         const struct prefix_info *pinfo)
> +{
> +    struct inet6_ifaddr *result_base = NULL;
> +    struct inet6_ifaddr *result = NULL;
> +    bool prfxs_equal;
> +
> +    result_base = result;
> +    rcu_read_lock();
> +    list_for_each_entry_rcu(ifp, &in6_dev->addr_list, if_list) {
> +        if (!net_eq(dev_net(ifp->idev->dev), net))
> +            continue;
> +        prfxs_equal =
> +            ipv6_prefix_equal(&pinfo->prefix, &ifp->addr, pinfo->prefix_len);
> +        if (prfxs_equal && pinfo->prefix_len == ifp->prefix_len) {
> +            result = ifp;
> +            in6_ifa_hold(ifp);
> +            break;
> +        }
> +    }
> +    rcu_read_unlock();
> +    if (result_base != result)
> +        ifp = result;
> +    else
> +        ifp = NULL;
> +
> +    return ifp;
> +}
> +
> 
> [Dmytro]:
> 1st initial stage is :
> +    result_base = result;
> 
> 2nd stage is (as you mention, 'result' will be assigned to 'ifp', in the process):
> +            result = ifp;
> 
> 3rd stage is to compare if  "result_base" and "result" are not equal (and take required action).
>  if (result_base != result)
> +        ifp = result;
> +    else
> +        ifp = NULL;
> 
> Looks more/less ok for me.

I think I see what you're trying to do here. Use result_base as a
"marker" or the base value?

But I'd say it makes the code harder to follow. It looks like this:

	result_base = NULL;
	result = NULL;

	result_base = result
	lock()
	for ...
		/* search logic */
	unlock()
	
	if (result == result_base)
		ifp = result
	else
		ifp = NULL
	return NULL

This would be a lot simpler, and functionally equivalent:

	result = NULL

	lock()
	for ...
		/* search logic */
	unlock()

	return result

Right?
Dmytro Shytyi Dec. 16, 2020, 9:56 p.m. UTC | #4 
Hello Jakub,

---- On Wed, 16 Dec 2020 18:28:31 +0100 Jakub Kicinski <kuba@kernel.org> wrote ----

 > On Wed, 16 Dec 2020 15:01:33 +0100 Dmytro Shytyi wrote: 
 > > Hello David, 
 > > 
 > > Thank you for your comment. 
 > > Asnwers in-line. 
 > > 
 > > Take care, 
 > > 
 > > Dmytro SHYTYI 
 > > 
 > > 
 > > ---- On Wed, 16 Dec 2020 01:00:49 +0100 David Miller <davem@davemloft.net> wrote ---- 
 > > 
 > >  > From: Dmytro Shytyi <dmytro@shytyi.net> 
 > >  > Date: Wed, 09 Dec 2020 04:27:54 +0100 
 > >  > 
 > >  > > Variable SLAAC [Can be activated via sysctl]: 
 > >  > > SLAAC with prefixes of arbitrary length in PIO (randomly 
 > >  > > generated hostID or stable privacy + privacy extensions). 
 > >  > > The main problem is that SLAAC RA or PD allocates a /64 by the Wireless 
 > >  > > carrier 4G, 5G to a mobile hotspot, however segmentation of the /64 via 
 > >  > > SLAAC is required so that downstream interfaces can be further subnetted. 
 > >  > > Example: uCPE device (4G + WI-FI enabled) receives /64 via Wireless, and 
 > >  > > assigns /72 to VNF-Firewall, /72 to WIFI, /72 to VNF-Router, /72 to 
 > >  > > Load-Balancer and /72 to wired connected devices. 
 > >  > > IETF document that defines problem statement: 
 > >  > > draft-mishra-v6ops-variable-slaac-problem-stmt 
 > >  > > IETF document that specifies variable slaac: 
 > >  > > draft-mishra-6man-variable-slaac 
 > >  > > 
 > >  > > Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net> 
 > >  > > --- 
 > >  > > diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h 
 > >  > > index dda61d150a13..67ca3925463c 100644 
 > >  > > --- a/include/linux/ipv6.h 
 > >  > > +++ b/include/linux/ipv6.h 
 > >  > > @@ -75,6 +75,7 @@ struct ipv6_devconf { 
 > >  > >      __s32        disable_policy; 
 > >  > >      __s32           ndisc_tclass; 
 > >  > >      __s32        rpl_seg_enabled; 
 > >  > > +    __s32        variable_slaac; 
 > >  > > 
 > >  > >      struct ctl_table_header *sysctl_header; 
 > >  > >  }; 
 > >  > > diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h 
 > >  > > index 13e8751bf24a..f2af4f9fba2d 100644 
 > >  > > --- a/include/uapi/linux/ipv6.h 
 > >  > > +++ b/include/uapi/linux/ipv6.h 
 > >  > > @@ -189,7 +189,8 @@ enum { 
 > >  > >      DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, 
 > >  > >      DEVCONF_NDISC_TCLASS, 
 > >  > >      DEVCONF_RPL_SEG_ENABLED, 
 > >  > > -    DEVCONF_MAX 
 > >  > > +    DEVCONF_MAX, 
 > >  > > +    DEVCONF_VARIABLE_SLAAC 
 > >  > >  }; 
 > >  > > 
 > >  > > 
 > >  > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c 
 > >  > > index eff2cacd5209..07afe4ce984e 100644 
 > >  > > --- a/net/ipv6/addrconf.c 
 > >  > > +++ b/net/ipv6/addrconf.c 
 > >  > > @@ -236,6 +236,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { 
 > >  > >      .addr_gen_mode        = IN6_ADDR_GEN_MODE_EUI64, 
 > >  > >      .disable_policy        = 0, 
 > >  > >      .rpl_seg_enabled    = 0, 
 > >  > > +    .variable_slaac        = 0, 
 > >  > >  }; 
 > >  > > 
 > >  > >  static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { 
 > >  > > @@ -291,6 +292,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { 
 > >  > >      .addr_gen_mode        = IN6_ADDR_GEN_MODE_EUI64, 
 > >  > >      .disable_policy        = 0, 
 > >  > >      .rpl_seg_enabled    = 0, 
 > >  > > +    .variable_slaac        = 0, 
 > >  > >  }; 
 > >  > > 
 > >  > >  /* Check if link is ready: is it up and is a valid qdisc available */ 
 > >  > > @@ -1340,9 +1342,15 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) 
 > >  > >          goto out; 
 > >  > >      } 
 > >  > >      in6_ifa_hold(ifp); 
 > >  > > -    memcpy(addr.s6_addr, ifp->addr.s6_addr, 8); 
 > >  > > -    ipv6_gen_rnd_iid(&addr); 
 > >  > > 
 > >  > > +    if (ifp->prefix_len == 64) { 
 > >  > > +        memcpy(addr.s6_addr, ifp->addr.s6_addr, 8); 
 > >  > > +        ipv6_gen_rnd_iid(&addr); 
 > >  > > +    } else if (ifp->prefix_len > 0 && ifp->prefix_len <= 128 && 
 > >  > > +           idev->cnf.variable_slaac) { 
 > >  > > +        get_random_bytes(addr.s6_addr, 16); 
 > >  > > +        ipv6_addr_prefix_copy(&addr, &ifp->addr, ifp->prefix_len); 
 > >  > > +    } 
 > >  > >      age = (now - ifp->tstamp) / HZ; 
 > >  > > 
 > >  > >      regen_advance = idev->cnf.regen_max_retry * 
 > >  > > @@ -2569,6 +2577,37 @@ static bool is_addr_mode_generate_stable(struct inet6_dev *idev) 
 > >  > >             idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM; 
 > >  > >  } 
 > >  > > 
 > >  > > +static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp, 
 > >  > > +                              struct inet6_dev *in6_dev, 
 > >  > > +                              struct net *net, 
 > >  > > +                              const struct prefix_info *pinfo) 
 > >  > > +{ 
 > >  > > +    struct inet6_ifaddr *result_base = NULL; 
 > >  > > +    struct inet6_ifaddr *result = NULL; 
 > >  > > +    bool prfxs_equal; 
 > >  > > + 
 > >  > > +    result_base = result; 
 > >  > 
 > >  > This is NULL, are you sure you didn't mewan to init this to 'ifp' 
 > >  >  or similar instead? 
 > > 
 > > [Dmytro] I put the entire function to comment below the instructions. 
 > > [Dmytro]: 
 > > +static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp, 
 > > +                         struct inet6_dev *in6_dev, 
 > > +                         struct net *net, 
 > > +                         const struct prefix_info *pinfo) 
 > > +{ 
 > > +    struct inet6_ifaddr *result_base = NULL; 
 > > +    struct inet6_ifaddr *result = NULL; 
 > > +    bool prfxs_equal; 
 > > + 
 > > +    result_base = result; 
 > > +    rcu_read_lock(); 
 > > +    list_for_each_entry_rcu(ifp, &in6_dev->addr_list, if_list) { 
 > > +        if (!net_eq(dev_net(ifp->idev->dev), net)) 
 > > +            continue; 
 > > +        prfxs_equal = 
 > > +            ipv6_prefix_equal(&pinfo->prefix, &ifp->addr, pinfo->prefix_len); 
 > > +        if (prfxs_equal && pinfo->prefix_len == ifp->prefix_len) { 
 > > +            result = ifp; 
 > > +            in6_ifa_hold(ifp); 
 > > +            break; 
 > > +        } 
 > > +    } 
 > > +    rcu_read_unlock(); 
 > > +    if (result_base != result) 
 > > +        ifp = result; 
 > > +    else 
 > > +        ifp = NULL; 
 > > + 
 > > +    return ifp; 
 > > +} 
 > > + 
 > > 
 > > [Dmytro]: 
 > > 1st initial stage is : 
 > > +    result_base = result; 
 > > 
 > > 2nd stage is (as you mention, 'result' will be assigned to 'ifp', in the process): 
 > > +            result = ifp; 
 > > 
 > > 3rd stage is to compare if  "result_base" and "result" are not equal (and take required action). 
 > >  if (result_base != result) 
 > > +        ifp = result; 
 > > +    else 
 > > +        ifp = NULL; 
 > > 
 > > Looks more/less ok for me. 
 >  
 > I think I see what you're trying to do here. Use result_base as a 
 > "marker" or the base value? 
 >  
 > But I'd say it makes the code harder to follow. It looks like this: 
 >  
 >     result_base = NULL; 
 >     result = NULL; 
 >  
 >     result_base = result 
 >     lock() 
 >     for ... 
 >         /* search logic */ 
 >     unlock() 
 >      
 >     if (result == result_base) 
 >         ifp = result 
 >     else 
 >         ifp = NULL 
 >     return NULL 
 >  
 > This would be a lot simpler, and functionally equivalent: 
 >  
 >     result = NULL 
 >  
 >     lock() 
 >     for ... 
 >         /* search logic */ 
 >     unlock() 
 >  
 >     return result 
 >  
 > Right? 
 > 
[Dmytro]: I see and I agree. Understood.
diff mbox series

Patch

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index dda61d150a13..67ca3925463c 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -75,6 +75,7 @@  struct ipv6_devconf {
 	__s32		disable_policy;
 	__s32           ndisc_tclass;
 	__s32		rpl_seg_enabled;
+	__s32		variable_slaac;
 
 	struct ctl_table_header *sysctl_header;
 };
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 13e8751bf24a..f2af4f9fba2d 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -189,7 +189,8 @@  enum {
 	DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN,
 	DEVCONF_NDISC_TCLASS,
 	DEVCONF_RPL_SEG_ENABLED,
-	DEVCONF_MAX
+	DEVCONF_MAX,
+	DEVCONF_VARIABLE_SLAAC
 };
 
 
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index eff2cacd5209..07afe4ce984e 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -236,6 +236,7 @@  static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
 	.disable_policy		= 0,
 	.rpl_seg_enabled	= 0,
+	.variable_slaac		= 0,
 };
 
 static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -291,6 +292,7 @@  static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
 	.disable_policy		= 0,
 	.rpl_seg_enabled	= 0,
+	.variable_slaac		= 0,
 };
 
 /* Check if link is ready: is it up and is a valid qdisc available */
@@ -1340,9 +1342,15 @@  static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
 		goto out;
 	}
 	in6_ifa_hold(ifp);
-	memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
-	ipv6_gen_rnd_iid(&addr);
 
+	if (ifp->prefix_len == 64) {
+		memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
+		ipv6_gen_rnd_iid(&addr);
+	} else if (ifp->prefix_len > 0 && ifp->prefix_len <= 128 &&
+		   idev->cnf.variable_slaac) {
+		get_random_bytes(addr.s6_addr, 16);
+		ipv6_addr_prefix_copy(&addr, &ifp->addr, ifp->prefix_len);
+	}
 	age = (now - ifp->tstamp) / HZ;
 
 	regen_advance = idev->cnf.regen_max_retry *
@@ -2569,6 +2577,37 @@  static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
 	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
 }
 
+static struct inet6_ifaddr *ipv6_cmp_rcvd_prsnt_prfxs(struct inet6_ifaddr *ifp,
+						      struct inet6_dev *in6_dev,
+						      struct net *net,
+						      const struct prefix_info *pinfo)
+{
+	struct inet6_ifaddr *result_base = NULL;
+	struct inet6_ifaddr *result = NULL;
+	bool prfxs_equal;
+
+	result_base = result;
+	rcu_read_lock();
+	list_for_each_entry_rcu(ifp, &in6_dev->addr_list, if_list) {
+		if (!net_eq(dev_net(ifp->idev->dev), net))
+			continue;
+		prfxs_equal =
+			ipv6_prefix_equal(&pinfo->prefix, &ifp->addr, pinfo->prefix_len);
+		if (prfxs_equal && pinfo->prefix_len == ifp->prefix_len) {
+			result = ifp;
+			in6_ifa_hold(ifp);
+			break;
+		}
+	}
+	rcu_read_unlock();
+	if (result_base != result)
+		ifp = result;
+	else
+		ifp = NULL;
+
+	return ifp;
+}
+
 int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
 				 const struct prefix_info *pinfo,
 				 struct inet6_dev *in6_dev,
@@ -2576,9 +2615,17 @@  int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
 				 u32 addr_flags, bool sllao, bool tokenized,
 				 __u32 valid_lft, u32 prefered_lft)
 {
-	struct inet6_ifaddr *ifp = ipv6_get_ifaddr(net, addr, dev, 1);
+	struct inet6_ifaddr *ifp = NULL;
+	int plen = pinfo->prefix_len;
 	int create = 0;
 
+	if (plen > 0 && plen <= 128 && plen != 64 &&
+	    in6_dev->cnf.addr_gen_mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
+	    in6_dev->cnf.variable_slaac)
+		ifp = ipv6_cmp_rcvd_prsnt_prfxs(ifp, in6_dev, net, pinfo);
+	else
+		ifp = ipv6_get_ifaddr(net, addr, dev, 1);
+
 	if (!ifp && valid_lft) {
 		int max_addresses = in6_dev->cnf.max_addresses;
 		struct ifa6_config cfg = {
@@ -2657,6 +2704,90 @@  int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(addrconf_prefix_rcv_add_addr);
 
+static bool ipv6_reserved_interfaceid(struct in6_addr address)
+{
+	if ((address.s6_addr32[2] | address.s6_addr32[3]) == 0)
+		return true;
+
+	if (address.s6_addr32[2] == htonl(0x02005eff) &&
+	    ((address.s6_addr32[3] & htonl(0xfe000000)) == htonl(0xfe000000)))
+		return true;
+
+	if (address.s6_addr32[2] == htonl(0xfdffffff) &&
+	    ((address.s6_addr32[3] & htonl(0xffffff80)) == htonl(0xffffff80)))
+		return true;
+
+	return false;
+}
+
+static int ipv6_gen_addr_var_plen(struct in6_addr *address,
+				  u8 dad_count,
+				  const struct inet6_dev *idev,
+				  unsigned int rcvd_prfx_len,
+				  bool stable_privacy_mode)
+{
+	static union {
+		char __data[SHA1_BLOCK_SIZE];
+		struct {
+			struct in6_addr secret;
+			__be32 prefix[2];
+			unsigned char hwaddr[MAX_ADDR_LEN];
+			u8 dad_count;
+		} __packed;
+	} data;
+	static __u32 workspace[SHA1_WORKSPACE_WORDS];
+	static __u32 digest[SHA1_DIGEST_WORDS];
+	struct net *net = dev_net(idev->dev);
+	static DEFINE_SPINLOCK(lock);
+	struct in6_addr secret;
+	struct in6_addr temp;
+
+	BUILD_BUG_ON(sizeof(data.__data) != sizeof(data));
+
+	if (stable_privacy_mode) {
+		if (idev->cnf.stable_secret.initialized)
+			secret = idev->cnf.stable_secret.secret;
+		else if (net->ipv6.devconf_dflt->stable_secret.initialized)
+			secret = net->ipv6.devconf_dflt->stable_secret.secret;
+		else
+			return -1;
+	}
+
+retry:
+	spin_lock_bh(&lock);
+	if (stable_privacy_mode) {
+		sha1_init(digest);
+		memset(&data, 0, sizeof(data));
+		memset(workspace, 0, sizeof(workspace));
+		memcpy(data.hwaddr, idev->dev->perm_addr, idev->dev->addr_len);
+		data.prefix[0] = address->s6_addr32[0];
+		data.prefix[1] = address->s6_addr32[1];
+		data.secret = secret;
+		data.dad_count = dad_count;
+
+		sha1_transform(digest, data.__data, workspace);
+
+		temp.s6_addr32[0] = (__force __be32)digest[0];
+		temp.s6_addr32[1] = (__force __be32)digest[1];
+		temp.s6_addr32[2] = (__force __be32)digest[2];
+		temp.s6_addr32[3] = (__force __be32)digest[3];
+	} else {
+		get_random_bytes(temp.s6_addr32, 16);
+	}
+
+	spin_unlock_bh(&lock);
+
+	if (ipv6_reserved_interfaceid(temp)) {
+		dad_count++;
+		if (dad_count > dev_net(idev->dev)->ipv6.sysctl.idgen_retries)
+			return -1;
+		goto retry;
+	}
+	ipv6_addr_prefix_copy(&temp, address, rcvd_prfx_len);
+	*address = temp;
+	return 0;
+}
+
 void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 {
 	struct prefix_info *pinfo;
@@ -2781,9 +2912,34 @@  void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 				dev_addr_generated = true;
 			}
 			goto ok;
+		} else if (pinfo->prefix_len != 64 &&
+			   pinfo->prefix_len > 0 && pinfo->prefix_len <= 128 &&
+			   in6_dev->cnf.variable_slaac) {
+			/* SLAAC with prefixes of arbitrary length (Variable SLAAC).
+			 * draft-mishra-6man-variable-slaac
+			 * draft-mishra-v6ops-variable-slaac-problem-stmt
+			 */
+			memcpy(&addr, &pinfo->prefix, 16);
+			if (in6_dev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY) {
+				if (!ipv6_gen_addr_var_plen(&addr,
+							    0,
+							    in6_dev,
+							    pinfo->prefix_len,
+							    true)) {
+					addr_flags |= IFA_F_STABLE_PRIVACY;
+					goto ok;
+				}
+			} else if (!ipv6_gen_addr_var_plen(&addr,
+							   0,
+							   in6_dev,
+							   pinfo->prefix_len,
+							   false)) {
+				goto ok;
+			}
+		} else {
+			net_dbg_ratelimited("IPv6: Prefix with unexpected length %d\n",
+					    pinfo->prefix_len);
 		}
-		net_dbg_ratelimited("IPv6 addrconf: prefix with wrong length %d\n",
-				    pinfo->prefix_len);
 		goto put;
 
 ok:
@@ -3186,22 +3342,6 @@  void addrconf_add_linklocal(struct inet6_dev *idev,
 }
 EXPORT_SYMBOL_GPL(addrconf_add_linklocal);
 
-static bool ipv6_reserved_interfaceid(struct in6_addr address)
-{
-	if ((address.s6_addr32[2] | address.s6_addr32[3]) == 0)
-		return true;
-
-	if (address.s6_addr32[2] == htonl(0x02005eff) &&
-	    ((address.s6_addr32[3] & htonl(0xfe000000)) == htonl(0xfe000000)))
-		return true;
-
-	if (address.s6_addr32[2] == htonl(0xfdffffff) &&
-	    ((address.s6_addr32[3] & htonl(0xffffff80)) == htonl(0xffffff80)))
-		return true;
-
-	return false;
-}
-
 static int ipv6_generate_stable_address(struct in6_addr *address,
 					u8 dad_count,
 					const struct inet6_dev *idev)
@@ -5517,6 +5657,7 @@  static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 	array[DEVCONF_DISABLE_POLICY] = cnf->disable_policy;
 	array[DEVCONF_NDISC_TCLASS] = cnf->ndisc_tclass;
 	array[DEVCONF_RPL_SEG_ENABLED] = cnf->rpl_seg_enabled;
+	array[DEVCONF_VARIABLE_SLAAC] = cnf->variable_slaac;
 }
 
 static inline size_t inet6_ifla6_size(void)
@@ -6897,6 +7038,13 @@  static const struct ctl_table addrconf_sysctl[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	{
+		.procname	= "variable_slaac",
+		.data		= &ipv6_devconf.variable_slaac,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
 	{
 		/* sentinel */
 	}