Subject: Re: [PATCH net-next v2 1/1] net: Allow a rule to track originating protocol

From: Ido Schimmel <[email-masked]>
Date: Thu, 22 Feb 2018 10:23:09 +0200

Hi Donald,

On Tue, Feb 20, 2018 at 08:55:58AM -0500, Donald Sharp wrote:
> Allow a rule that is being added/deleted/modified or
> dumped to contain the originating protocol's id.
> 
> The protocol is handled just like a routes originating
> protocol is.  This is especially useful because there
> is starting to be a plethora of different user space
> programs adding rules.
> 
> Allow the vrf device to specify that the kernel is the originator
> of the rule created for this device.
> 
> Signed-off-by: Donald Sharp <[email-masked]>
> ---
>  drivers/net/vrf.c              | 1 +
>  include/net/fib_rules.h        | 3 ++-
>  include/uapi/linux/fib_rules.h | 2 +-
>  net/core/fib_rules.c           | 7 ++++++-
>  4 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
> index 139c61c8244a..ec6d2d623b60 100644
> --- a/drivers/net/vrf.c
> +++ b/drivers/net/vrf.c
> @@ -1175,6 +1175,7 @@ static int vrf_fib_rule(const struct net_device *dev, __u8 family, bool add_it)
>  	memset(frh, 0, sizeof(*frh));
>  	frh->family = family;
>  	frh->action = FR_ACT_TO_TBL;
> +	frh->proto = RTPROT_KERNEL;
>  
>  	if (nla_put_u8(skb, FRA_L3MDEV, 1))
>  		goto nla_put_failure;
> diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h
> index 648caf90ec07..b166ef07e6d4 100644
> --- a/include/net/fib_rules.h
> +++ b/include/net/fib_rules.h
> @@ -26,7 +26,8 @@ struct fib_rule {
>  	u32			table;
>  	u8			action;
>  	u8			l3mdev;
> -	/* 2 bytes hole, try to use */
> +	u8                      proto;
> +	/* 1 byte hole, try to use */
>  	u32			target;
>  	__be64			tun_id;
>  	struct fib_rule __rcu	*ctarget;
> diff --git a/include/uapi/linux/fib_rules.h b/include/uapi/linux/fib_rules.h
> index 2b642bf9b5a0..925539172d5b 100644
> --- a/include/uapi/linux/fib_rules.h
> +++ b/include/uapi/linux/fib_rules.h
> @@ -23,8 +23,8 @@ struct fib_rule_hdr {
>  	__u8		tos;
>  
>  	__u8		table;
> +	__u8		proto;
>  	__u8		res1;	/* reserved */
> -	__u8		res2;	/* reserved */
>  	__u8		action;
>  
>  	__u32		flags;
> diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
> index 98e1066c3d55..c1d4ab5b2d9f 100644
> --- a/net/core/fib_rules.c
> +++ b/net/core/fib_rules.c
> @@ -51,6 +51,7 @@ int fib_default_rule_add(struct fib_rules_ops *ops,
>  	r->pref = pref;
>  	r->table = table;
>  	r->flags = flags;
> +	r->proto = RTPROT_KERNEL;
>  	r->fr_net = ops->fro_net;
>  	r->uid_range = fib_kuid_range_unset;
>  
> @@ -465,6 +466,7 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
>  	}
>  	refcount_set(&rule->refcnt, 1);
>  	rule->fr_net = net;
> +	rule->proto = frh->proto;
>  
>  	rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
>  	                              : fib_default_rule_pref(ops);
> @@ -664,6 +666,9 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
>  	}
>  
>  	list_for_each_entry(rule, &ops->rules_list, list) {
> +		if (frh->proto && (frh->proto != rule->proto))
> +			continue;

This breaks my scripts:
# ip -4 rule show
0:      from all lookup local
32766:  from all lookup main
32767:  from all lookup default

# ip -4 rule del pref 0
RTNETLINK answers: No such file or directory

Using iproute 4.15 in Fedora 27:
# ip -V
ip utility, iproute2-ss180129

Problem is iproute sets protocol to RTPROT_BOOT while rules are
installed with RTPROT_KERNEL.

Maybe add FRA_PROTOCOL?

Thanks!

> +
>  		if (frh->action && (frh->action != rule->action))
>  			continue;
>  
> @@ -808,9 +813,9 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
>  	if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
>  		goto nla_put_failure;
>  	frh->res1 = 0;
> -	frh->res2 = 0;
>  	frh->action = rule->action;
>  	frh->flags = rule->flags;
> +	frh->proto = rule->proto;
>  
>  	if (rule->action == FR_ACT_GOTO &&
>  	    rcu_access_pointer(rule->ctarget) == NULL)
> -- 
> 2.14.3
>