Subject: Re: [PATCH v3 net-next 03/14] net: bridge: mst: Support setting and reporting MST port states

From: Tobias Waldekranz <[email-masked]>
Date: Mon, 14 Mar 2022 13:38:34 +0100

On Mon, Mar 14, 2022 at 12:37, Nikolay Aleksandrov <[email-masked]> wrote:
> On 14/03/2022 11:52, Tobias Waldekranz wrote:
>> Make it possible to change the port state in a given MSTI by extending
>> the bridge port netlink interface (RTM_SETLINK on PF_BRIDGE).The
>> proposed iproute2 interface would be:
>> 
>>     bridge mst set dev <PORT> msti <MSTI> state <STATE>
>> 
>> Current states in all applicable MSTIs can also be dumped via a
>> corresponding RTM_GETLINK. The proposed iproute interface looks like
>> this:
>> 
>> $ bridge mst
>> port              msti
>> vb1               0
>> 		    state forwarding
>> 		  100
>> 		    state disabled
>> vb2               0
>> 		    state forwarding
>> 		  100
>> 		    state forwarding
>> 
>> The preexisting per-VLAN states are still valid in the MST
>> mode (although they are read-only), and can be queried as usual if one
>> is interested in knowing a particular VLAN's state without having to
>> care about the VID to MSTI mapping (in this example VLAN 20 and 30 are
>> bound to MSTI 100):
>> 
>> $ bridge -d vlan
>> port              vlan-id
>> vb1               10
>> 		    state forwarding mcast_router 1
>> 		  20
>> 		    state disabled mcast_router 1
>> 		  30
>> 		    state disabled mcast_router 1
>> 		  40
>> 		    state forwarding mcast_router 1
>> vb2               10
>> 		    state forwarding mcast_router 1
>> 		  20
>> 		    state forwarding mcast_router 1
>> 		  30
>> 		    state forwarding mcast_router 1
>> 		  40
>> 		    state forwarding mcast_router 1
>> 
>> Signed-off-by: Tobias Waldekranz <[email-masked]>
>> ---
>
> Hi Tobias,
> A few comments below..
>
>>  include/uapi/linux/if_bridge.h |  17 ++++++
>>  include/uapi/linux/rtnetlink.h |   1 +
>>  net/bridge/br_mst.c            | 105 +++++++++++++++++++++++++++++++++
>>  net/bridge/br_netlink.c        |  32 +++++++++-
>>  net/bridge/br_private.h        |  15 +++++
>>  5 files changed, 169 insertions(+), 1 deletion(-)
>> 
>> diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
>> index f60244b747ae..879dfaef8da0 100644
>> --- a/include/uapi/linux/if_bridge.h
>> +++ b/include/uapi/linux/if_bridge.h
>> @@ -122,6 +122,7 @@ enum {
>>  	IFLA_BRIDGE_VLAN_TUNNEL_INFO,
>>  	IFLA_BRIDGE_MRP,
>>  	IFLA_BRIDGE_CFM,
>> +	IFLA_BRIDGE_MST,
>>  	__IFLA_BRIDGE_MAX,
>>  };
>>  #define IFLA_BRIDGE_MAX (__IFLA_BRIDGE_MAX - 1)
>> @@ -453,6 +454,21 @@ enum {
>>  
>>  #define IFLA_BRIDGE_CFM_CC_PEER_STATUS_MAX (__IFLA_BRIDGE_CFM_CC_PEER_STATUS_MAX - 1)
>>  
>> +enum {
>> +	IFLA_BRIDGE_MST_UNSPEC,
>> +	IFLA_BRIDGE_MST_ENTRY,
>> +	__IFLA_BRIDGE_MST_MAX,
>> +};
>> +#define IFLA_BRIDGE_MST_MAX (__IFLA_BRIDGE_MST_MAX - 1)
>> +
>> +enum {
>> +	IFLA_BRIDGE_MST_ENTRY_UNSPEC,
>> +	IFLA_BRIDGE_MST_ENTRY_MSTI,
>> +	IFLA_BRIDGE_MST_ENTRY_STATE,
>> +	__IFLA_BRIDGE_MST_ENTRY_MAX,
>> +};
>> +#define IFLA_BRIDGE_MST_ENTRY_MAX (__IFLA_BRIDGE_MST_ENTRY_MAX - 1)
>> +
>>  struct bridge_stp_xstats {
>>  	__u64 transition_blk;
>>  	__u64 transition_fwd;
>> @@ -786,4 +802,5 @@ enum {
>>  	__BRIDGE_QUERIER_MAX
>>  };
>>  #define BRIDGE_QUERIER_MAX (__BRIDGE_QUERIER_MAX - 1)
>> +
>
> stray new line

Well that's embarrassing :)

>>  #endif /* _UAPI_LINUX_IF_BRIDGE_H */
>> diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
>> index 51530aade46e..83849a37db5b 100644
>> --- a/include/uapi/linux/rtnetlink.h
>> +++ b/include/uapi/linux/rtnetlink.h
>> @@ -817,6 +817,7 @@ enum {
>>  #define RTEXT_FILTER_MRP	(1 << 4)
>>  #define RTEXT_FILTER_CFM_CONFIG	(1 << 5)
>>  #define RTEXT_FILTER_CFM_STATUS	(1 << 6)
>> +#define RTEXT_FILTER_MST	(1 << 7)
>>  
>>  /* End of information exported to user level */
>>  
>> diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
>> index 78ef5fea4d2b..df65aa7701c1 100644
>> --- a/net/bridge/br_mst.c
>> +++ b/net/bridge/br_mst.c
>> @@ -124,3 +124,108 @@ int br_mst_set_enabled(struct net_bridge *br, bool on,
>>  	br_opt_toggle(br, BROPT_MST_ENABLED, on);
>>  	return 0;
>>  }
>> +
>> +int br_mst_fill_info(struct sk_buff *skb, struct net_bridge_vlan_group *vg)
>
> const vg
>
>> +{
>> +	struct net_bridge_vlan *v;
>
> const v
>
>> +	struct nlattr *nest;
>> +	unsigned long *seen;
>> +	int err = 0;
>> +
>> +	seen = bitmap_zalloc(VLAN_N_VID, 0);
>> +	if (!seen)
>> +		return -ENOMEM;
>> +
>> +	list_for_each_entry(v, &vg->vlan_list, vlist) {
>> +		if (test_bit(v->brvlan->msti, seen))
>> +			continue;
>> +
>> +		nest = nla_nest_start_noflag(skb, IFLA_BRIDGE_MST_ENTRY);
>> +		if (!nest ||
>> +		    nla_put_u16(skb, IFLA_BRIDGE_MST_ENTRY_MSTI, v->brvlan->msti) ||
>> +		    nla_put_u8(skb, IFLA_BRIDGE_MST_ENTRY_STATE, v->state)) {
>> +			err = -EMSGSIZE;
>> +			break;
>> +		}
>> +		nla_nest_end(skb, nest);
>> +
>> +		set_bit(v->brvlan->msti, seen);
>
> __set_bit()
>
>> +	}
>> +
>> +	kfree(seen);
>> +	return err;
>> +}
>> +
>> +static const struct nla_policy br_mst_nl_policy[IFLA_BRIDGE_MST_ENTRY_MAX + 1] = {
>> +	[IFLA_BRIDGE_MST_ENTRY_MSTI] = NLA_POLICY_RANGE(NLA_U16,
>> +						   1, /* 0 reserved for CST */
>> +						   VLAN_N_VID - 1),
>> +	[IFLA_BRIDGE_MST_ENTRY_STATE] = NLA_POLICY_RANGE(NLA_U8,
>> +						    BR_STATE_DISABLED,
>> +						    BR_STATE_BLOCKING),
>> +};
>> +
>> +static int br_mst_parse_one(struct net_bridge_port *p,
>> +			    const struct nlattr *attr,
>> +			    struct netlink_ext_ack *extack)
>> +{
>
> I'd either set the state after parsing, so this function just does what it
> says (parse) or I'd rename it.
>
>> +	struct nlattr *tb[IFLA_BRIDGE_MST_ENTRY_MAX + 1];
>> +	u16 msti;
>> +	u8 state;
>> +	int err;
>> +
>> +	err = nla_parse_nested(tb, IFLA_BRIDGE_MST_ENTRY_MAX, attr,
>> +			       br_mst_nl_policy, extack);
>> +	if (err)
>> +		return err;
>> +
>> +	if (!tb[IFLA_BRIDGE_MST_ENTRY_MSTI]) {
>> +		NL_SET_ERR_MSG_MOD(extack, "MSTI not specified");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (!tb[IFLA_BRIDGE_MST_ENTRY_STATE]) {
>> +		NL_SET_ERR_MSG_MOD(extack, "State not specified");
>> +		return -EINVAL;
>> +	}
>> +
>> +	msti = nla_get_u16(tb[IFLA_BRIDGE_MST_ENTRY_MSTI]);
>> +	state = nla_get_u8(tb[IFLA_BRIDGE_MST_ENTRY_STATE]);
>> +
>> +	br_mst_set_state(p, msti, state);
>> +	return 0;
>> +}
>> +
>> +int br_mst_parse(struct net_bridge_port *p, struct nlattr *mst_attr,
>> +		 struct netlink_ext_ack *extack)
>
> This doesn't just parse though, it also sets the state. Please rename it to
> something more appropriate.
>
> const mst_attr
>
>> +{
>> +	struct nlattr *attr;
>> +	int err, msts = 0;
>> +	int rem;
>> +
>> +	if (!br_opt_get(p->br, BROPT_MST_ENABLED)) {
>> +		NL_SET_ERR_MSG_MOD(extack, "Can't modify MST state when MST is disabled");
>> +		return -EBUSY;
>> +	}
>> +
>> +	nla_for_each_nested(attr, mst_attr, rem) {
>> +		switch (nla_type(attr)) {
>> +		case IFLA_BRIDGE_MST_ENTRY:
>> +			err = br_mst_parse_one(p, attr, extack);
>> +			break;
>> +		default:
>> +			continue;
>> +		}
>> +
>> +		msts++;
>> +		if (err)
>> +			break;
>> +	}
>> +
>> +	if (!msts) {
>> +		NL_SET_ERR_MSG_MOD(extack, "Found no MST entries to process");
>> +		err = -EINVAL;
>> +	}
>> +
>> +	return err;
>> +}
>> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
>> index 7d4432ca9a20..d2b4550f30d6 100644
>> --- a/net/bridge/br_netlink.c
>> +++ b/net/bridge/br_netlink.c
>> @@ -485,7 +485,8 @@ static int br_fill_ifinfo(struct sk_buff *skb,
>>  			   RTEXT_FILTER_BRVLAN_COMPRESSED |
>>  			   RTEXT_FILTER_MRP |
>>  			   RTEXT_FILTER_CFM_CONFIG |
>> -			   RTEXT_FILTER_CFM_STATUS)) {
>> +			   RTEXT_FILTER_CFM_STATUS |
>> +			   RTEXT_FILTER_MST)) {
>>  		af = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
>>  		if (!af)
>>  			goto nla_put_failure;
>> @@ -564,7 +565,28 @@ static int br_fill_ifinfo(struct sk_buff *skb,
>>  		nla_nest_end(skb, cfm_nest);
>>  	}
>>  
>> +	if ((filter_mask & RTEXT_FILTER_MST) &&
>> +	    br_opt_get(br, BROPT_MST_ENABLED) && port) {
>> +		struct net_bridge_vlan_group *vg = nbp_vlan_group(port);
>
> const vg
>
>> +		struct nlattr *mst_nest;
>> +		int err;
>> +
>> +		if (!vg || !vg->num_vlans)
>> +			goto done;
>> +
>> +		mst_nest = nla_nest_start(skb, IFLA_BRIDGE_MST);
>> +		if (!mst_nest)
>> +			goto nla_put_failure;
>> +
>> +		err = br_mst_fill_info(skb, vg);
>> +		if (err)
>> +			goto nla_put_failure;
>> +
>> +		nla_nest_end(skb, mst_nest);
>> +	}
>> +
>
> I think you should also update br_get_link_af_size_filtered() to account for the
> new dump attributes based on the filter. I'd adjust vinfo_sz based on the filter
> flag.
>
>>  done:
>> +
>>  	if (af)
>>  		nla_nest_end(skb, af);
>>  	nlmsg_end(skb, nlh);
>> @@ -803,6 +825,14 @@ static int br_afspec(struct net_bridge *br,
>>  			if (err)
>>  				return err;
>>  			break;
>> +		case IFLA_BRIDGE_MST:
>> +			if (cmd != RTM_SETLINK || !p)
>> +				return -EINVAL;
>
> These are two different errors, please set extack appropriately
> for each error.

Thanks for the review, all of the above will be fixed in v4.