Re: [PATCH RFC 6/7] bridge: cfm: Netlink Notifications.

From: henrik.bjoernlund@xxxxxxxxxxxxx
Date: Tue Sep 15 2020 - 06:01:55 EST

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Thanks for the review. Comments below.

The 09/08/2020 13:54, Nikolay Aleksandrov wrote:
>
> On Fri, 2020-09-04 at 09:15 +0000, Henrik Bjoernlund wrote:
> > This is the implementation of Netlink notifications out of CFM.
> >
> > Notifications are initiated whenever a state change happens in CFM.
> >
> [snip]
> > @@ -445,6 +458,7 @@ static int br_cfm_frame_rx(struct net_bridge_port *port, struct sk_buff *skb)
> > peer_mep->cc_status.ccm_defect = false;
> >
> > /* Change in CCM defect status - notify */
> > + br_cfm_notify(RTM_NEWLINK, port);
> >
> > /* Start CCM RX timer */
> > ccm_rx_timer_start(peer_mep);
> > @@ -874,6 +888,35 @@ int br_cfm_cc_counters_clear(struct net_bridge *br, const u32 instance,
> > return 0;
> > }
> >
> > +int br_cfm_mep_count(struct net_bridge *br, u32 *count)
> > +{
> > + struct br_cfm_mep *mep;
>
> Leave a blank line between local variable definitions and code.
>
I will change that as suggested.

> > + *count = 0;
> > +
> > + rcu_read_lock();
> > + list_for_each_entry_rcu(mep, &br->mep_list, head)
> > + * count += 1;
>
> please remove the extra space
>
I will change that as suggested.

> > + rcu_read_unlock();
> > +
> > + return 0;
> > +}
> > +
> > +int br_cfm_peer_mep_count(struct net_bridge *br, u32 *count)
> > +{
> > + struct br_cfm_peer_mep *peer_mep;
> > + struct br_cfm_mep *mep;
>
> Leave a blank line between local variable definitions and code.
>
I will change that as suggested.

> > + *count = 0;
> > +
> > + rcu_read_lock();
> > + list_for_each_entry_rcu(mep, &br->mep_list, head) {
> > + list_for_each_entry_rcu(peer_mep, &mep->peer_mep_list, head)
> > + * count += 1;
>
> please remove the extra space
>
I will change that as suggested.

> > + }
> > + rcu_read_unlock();
> > +
> > + return 0;
> > +}
> > +
> > bool br_cfm_created(struct net_bridge *br)
> > {
> > return !list_empty(&br->mep_list);
> > diff --git a/net/bridge/br_cfm_netlink.c b/net/bridge/br_cfm_netlink.c
> > index 4e39aab1cd0b..13664ac8608a 100644
> > --- a/net/bridge/br_cfm_netlink.c
> > +++ b/net/bridge/br_cfm_netlink.c
> > @@ -582,7 +582,9 @@ int br_cfm_config_fill_info(struct sk_buff *skb, struct net_bridge *br)
> > return -EMSGSIZE;
> > }
> >
> > -int br_cfm_status_fill_info(struct sk_buff *skb, struct net_bridge *br)
> > +int br_cfm_status_fill_info(struct sk_buff *skb,
> > + struct net_bridge *br,
> > + bool getlink)
> > {
> > struct nlattr *tb, *cfm_tb;
> > struct br_cfm_mep *mep;
> > @@ -613,10 +615,12 @@ int br_cfm_status_fill_info(struct sk_buff *skb, struct net_bridge *br)
> > mep->status.rx_level_low_seen))
> > goto nla_put_failure;
> >
> > - /* Clear all 'seen' indications */
> > - mep->status.opcode_unexp_seen = false;
> > - mep->status.version_unexp_seen = false;
> > - mep->status.rx_level_low_seen = false;
> > + if (getlink) { /* Only clear if this is a GETLINK */
> > + /* Clear all 'seen' indications */
> > + mep->status.opcode_unexp_seen = false;
> > + mep->status.version_unexp_seen = false;
> > + mep->status.rx_level_low_seen = false;
> > + }
> >
> > nla_nest_end(skb, tb);
> >
> > @@ -662,10 +666,12 @@ int br_cfm_status_fill_info(struct sk_buff *skb, struct net_bridge *br)
> > peer_mep->cc_status.seq_unexp_seen))
> > goto nla_put_failure;
> >
> > - /* Clear all 'seen' indications */
> > - peer_mep->cc_status.seen = false;
> > - peer_mep->cc_status.tlv_seen = false;
> > - peer_mep->cc_status.seq_unexp_seen = false;
> > + if (getlink) { /* Only clear if this is a GETLINK */
> > + /* Clear all 'seen' indications */
> > + peer_mep->cc_status.seen = false;
> > + peer_mep->cc_status.tlv_seen = false;
> > + peer_mep->cc_status.seq_unexp_seen = false;
>
> Why clear these on GETLINK? This sounds like it should be a set op.
>
The idea is that when getting the CFM status any '_seen' indications are
cleared so that they are giving information about what was seen since
last get.
I assume this is a get/clear atomic operations as rcu is held.
If you think this must be changed to a seperate clear_set operation I
will ofc do it.

> > + }
> >
> > nla_nest_end(skb, tb);
> > }
> > diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> > index 6de5cb1295f6..f2e885521f4f 100644
> > --- a/net/bridge/br_netlink.c
> > +++ b/net/bridge/br_netlink.c
> > @@ -94,9 +94,11 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
> > {
> > struct net_bridge_vlan_group *vg = NULL;
> > struct net_bridge_port *p = NULL;
> > - struct net_bridge *br;
> > - int num_vlan_infos;
> > + struct net_bridge *br = NULL;
> > + u32 num_cfm_peer_mep_infos;
> > + u32 num_cfm_mep_infos;
> > size_t vinfo_sz = 0;
> > + int num_vlan_infos;
> >
> > rcu_read_lock();
> > if (netif_is_bridge_port(dev)) {
> > @@ -115,6 +117,52 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
> > /* Each VLAN is returned in bridge_vlan_info along with flags */
> > vinfo_sz += num_vlan_infos * nla_total_size(sizeof(struct bridge_vlan_info));
> >
> > + if (!(filter_mask & RTEXT_FILTER_CFM_STATUS))
> > + return vinfo_sz;
> > +
> > + if (!br)
> > + return vinfo_sz;
> > +
> > + /* CFM status info must be added */
> > + if (br_cfm_mep_count(br, &num_cfm_mep_infos))
> > + return vinfo_sz;
> > +
> > + if (br_cfm_peer_mep_count(br, &num_cfm_peer_mep_infos))
> > + return vinfo_sz;
> > +
>
> Can these return non-0 at all?
>
I have removed check of return value.

> > + vinfo_sz += nla_total_size(0); /* IFLA_BRIDGE_CFM */
> > + /* For each status struct the MEP instance (u32) is added */
> > + /* MEP instance (u32) + br_cfm_mep_status */
> > + vinfo_sz += num_cfm_mep_infos *
> > + /*IFLA_BRIDGE_CFM_MEP_STATUS_INSTANCE */
> > + (nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_MEP_STATUS_OPCODE_UNEXP_SEEN */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_MEP_STATUS_VERSION_UNEXP_SEEN */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_MEP_STATUS_RX_LEVEL_LOW_SEEN */
> > + + nla_total_size(sizeof(u32)));
> > + /* MEP instance (u32) + br_cfm_cc_peer_status */
> > + vinfo_sz += num_cfm_peer_mep_infos *
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_INSTANCE */
> > + (nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_PEER_MEPID */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_CCM_DEFECT */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_RDI */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_PORT_TLV_VALUE */
> > + + nla_total_size(sizeof(u8))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_IF_TLV_VALUE */
> > + + nla_total_size(sizeof(u8))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEEN */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_TLV_SEEN */
> > + + nla_total_size(sizeof(u32))
> > + /* IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEQ_UNEXP_SEEN */
> > + + nla_total_size(sizeof(u32)));
> > +
> > return vinfo_sz;
> > }
> >
> > @@ -378,7 +426,8 @@ static int br_fill_ifvlaninfo(struct sk_buff *skb,
> > static int br_fill_ifinfo(struct sk_buff *skb,
> > const struct net_bridge_port *port,
> > u32 pid, u32 seq, int event, unsigned int flags,
> > - u32 filter_mask, const struct net_device *dev)
> > + u32 filter_mask, const struct net_device *dev,
> > + bool getlink)
> > {
> > u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
> > struct net_bridge *br;
> > @@ -515,7 +564,7 @@ static int br_fill_ifinfo(struct sk_buff *skb,
> > goto nla_put_failure;
> >
> > rcu_read_lock();
> > - err = br_cfm_status_fill_info(skb, br);
> > + err = br_cfm_status_fill_info(skb, br, getlink);
> > rcu_read_unlock();
> >
> > if (err)
> > @@ -533,11 +582,9 @@ static int br_fill_ifinfo(struct sk_buff *skb,
> > return -EMSGSIZE;
> > }
> >
> > -/* Notify listeners of a change in bridge or port information */
> > -void br_ifinfo_notify(int event, const struct net_bridge *br,
> > - const struct net_bridge_port *port)
> > +void br_info_notify(int event, const struct net_bridge *br,
> > + const struct net_bridge_port *port, u32 filter)
> > {
> > - u32 filter = RTEXT_FILTER_BRVLAN_COMPRESSED;
> > struct net_device *dev;
> > struct sk_buff *skb;
> > int err = -ENOBUFS;
> > @@ -562,7 +609,7 @@ void br_ifinfo_notify(int event, const struct net_bridge *br,
> > if (skb == NULL)
> > goto errout;
> >
> > - err = br_fill_ifinfo(skb, port, 0, 0, event, 0, filter, dev);
> > + err = br_fill_ifinfo(skb, port, 0, 0, event, 0, filter, dev, false);
> > if (err < 0) {
> > /* -EMSGSIZE implies BUG in br_nlmsg_size() */
> > WARN_ON(err == -EMSGSIZE);
> > @@ -575,6 +622,15 @@ void br_ifinfo_notify(int event, const struct net_bridge *br,
> > rtnl_set_sk_err(net, RTNLGRP_LINK, err);
> > }
> >
> > +/* Notify listeners of a change in bridge or port information */
> > +void br_ifinfo_notify(int event, const struct net_bridge *br,
> > + const struct net_bridge_port *port)
> > +{
> > + u32 filter = RTEXT_FILTER_BRVLAN_COMPRESSED;
> > +
> > + return br_info_notify(event, br, port, filter);
> > +}
> > +
> > /*
> > * Dump information about all ports, in response to GETLINK
> > */
> > @@ -591,7 +647,7 @@ int br_getlink(struct sk_buff *skb, u32 pid, u32 seq,
> > return 0;
> >
> > return br_fill_ifinfo(skb, port, pid, seq, RTM_NEWLINK, nlflags,
> > - filter_mask, dev);
> > + filter_mask, dev, true);
> > }
> >
> > static int br_vlan_info(struct net_bridge *br, struct net_bridge_port *p,
> > diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> > index fe36592f7525..53bcbdd21f34 100644
> > --- a/net/bridge/br_private.h
> > +++ b/net/bridge/br_private.h
> > @@ -1370,7 +1370,11 @@ int br_cfm_parse(struct net_bridge *br, struct net_bridge_port *p,
> > int br_cfm_rx_frame_process(struct net_bridge_port *p, struct sk_buff *skb);
> > bool br_cfm_created(struct net_bridge *br);
> > int br_cfm_config_fill_info(struct sk_buff *skb, struct net_bridge *br);
> > -int br_cfm_status_fill_info(struct sk_buff *skb, struct net_bridge *br);
> > +int br_cfm_status_fill_info(struct sk_buff *skb,
> > + struct net_bridge *br,
> > + bool getlink);
> > +int br_cfm_mep_count(struct net_bridge *br, u32 *count);
> > +int br_cfm_peer_mep_count(struct net_bridge *br, u32 *count);
> > #else
> > static inline int br_cfm_parse(struct net_bridge *br, struct net_bridge_port *p,
> > struct nlattr *attr, int cmd,
> > @@ -1394,7 +1398,19 @@ static inline int br_cfm_config_fill_info(struct sk_buff *skb, struct net_bridge
> > return -EOPNOTSUPP;
> > }
> >
> > -static inline int br_cfm_status_fill_info(struct sk_buff *skb, struct net_bridge *br)
> > +static inline int br_cfm_status_fill_info(struct sk_buff *skb,
> > + struct net_bridge *br,
> > + bool getlink)
> > +{
> > + return -EOPNOTSUPP;
> > +}
> > +
> > +static inline int br_cfm_mep_count(struct net_bridge *br, u32 *count)
> > +{
> > + return -EOPNOTSUPP;
> > +}
> > +
> > +static inline int br_cfm_peer_mep_count(struct net_bridge *br, u32 *count)
> > {
> > return -EOPNOTSUPP;
> > }
> > @@ -1406,6 +1422,8 @@ int br_netlink_init(void);
> > void br_netlink_fini(void);
> > void br_ifinfo_notify(int event, const struct net_bridge *br,
> > const struct net_bridge_port *port);
> > +void br_info_notify(int event, const struct net_bridge *br,
> > + const struct net_bridge_port *port, u32 filter);
> > int br_setlink(struct net_device *dev, struct nlmsghdr *nlmsg, u16 flags,
> > struct netlink_ext_ack *extack);
> > int br_dellink(struct net_device *dev, struct nlmsghdr *nlmsg, u16 flags);
>

--
/Henrik

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