bridge: fix setlink/dellink notifications (02dba438) · Commits · 戴 / test

problems with bridge getlink/setlink notifications today: - bridge setlink generates two notifications to userspace - one from the bridge driver - one from rtnetlink.c (rtnl_bridge_notify) - dellink generates one notification from rtnetlink.c. Which means bridge setlink and dellink notifications are not consistent - Looking at the code it appears, If both BRIDGE_FLAGS_MASTER and BRIDGE_FLAGS_SELF were set, the size calculation in rtnl_bridge_notify can be wrong. Example: if you set both BRIDGE_FLAGS_MASTER and BRIDGE_FLAGS_SELF in a setlink request to rocker dev, rtnl_bridge_notify will allocate skb for one set of bridge attributes, but, both the bridge driver and rocker dev will try to add attributes resulting in twice the number of attributes being added to the skb. (rocker dev calls ndo_dflt_bridge_getlink) There are multiple options: 1) Generate one notification including all attributes from master and self: But, I don't think it will work, because both master and self may use the same attributes/policy. Cannot pack the same set of attributes in a single notification from both master and slave (duplicate attributes). 2) Generate one notification from master and the other notification from self (This seems to be ideal): For master: the master driver will send notification (bridge in this example) For self: the self driver will send notification (rocker in the above example. It can use helpers from rtnetlink.c to do so. Like the ndo_dflt_bridge_getlink api). This patch implements 2) (leaving the 'rtnl_bridge_notify' around to be used with 'self'). v1->v2 : - rtnl_bridge_notify is now called only for self, so, remove 'BRIDGE_FLAGS_SELF' check and cleanup a few things - rtnl_bridge_dellink used to always send a RTM_NEWLINK msg earlier. So, I have changed the notification from br_dellink to go as RTM_NEWLINK Signed-off-by:

Roopa Prabhu <roopa@cumulusnetworks.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/bridge/br_netlink.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -569,6 +569,11 @@ int br_dellink(struct net_device dev, struct nlmsghdr nlh)

		err = br_afspec((struct net_bridge *)netdev_priv(dev), p,
		afspec, RTM_DELLINK);
		if (err == 0)
		/* Send RTM_NEWLINK because userspace
		* expects RTM_NEWLINK for vlan dels
		*/
		br_ifinfo_notify(RTM_NEWLINK, p);

		return err;
		}

net/core/rtnetlink.c

+21 −24

Original line number	Diff line number	Diff line
		@@ -2880,32 +2880,24 @@ static inline size_t bridge_nlmsg_size(void)
		+ nla_total_size(sizeof(u16)); /* IFLA_BRIDGE_MODE */
		}

		static int rtnl_bridge_notify(struct net_device *dev, u16 flags)
		static int rtnl_bridge_notify(struct net_device *dev)
		{
		struct net *net = dev_net(dev);
		struct net_device *br_dev = netdev_master_upper_dev_get(dev);
		struct sk_buff *skb;
		int err = -EOPNOTSUPP;

		if (!dev->netdev_ops->ndo_bridge_getlink)
		return 0;

		skb = nlmsg_new(bridge_nlmsg_size(), GFP_ATOMIC);
		if (!skb) {
		err = -ENOMEM;
		goto errout;
		}

		if ((!flags \|\| (flags & BRIDGE_FLAGS_MASTER)) &&
		br_dev && br_dev->netdev_ops->ndo_bridge_getlink) {
		err = br_dev->netdev_ops->ndo_bridge_getlink(skb, 0, 0, dev, 0);
		if (err < 0)
		goto errout;
		}

		if ((flags & BRIDGE_FLAGS_SELF) &&
		dev->netdev_ops->ndo_bridge_getlink) {
		err = dev->netdev_ops->ndo_bridge_getlink(skb, 0, 0, dev, 0);
		if (err < 0)
		goto errout;
		}

		rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
		return 0;
		@@ -2975,16 +2967,18 @@ static int rtnl_bridge_setlink(struct sk_buff skb, struct nlmsghdr nlh)
		err = -EOPNOTSUPP;
		else
		err = dev->netdev_ops->ndo_bridge_setlink(dev, nlh);

		if (!err)
		if (!err) {
		flags &= ~BRIDGE_FLAGS_SELF;

		/* Generate event to notify upper layer of bridge
		* change
		*/
		err = rtnl_bridge_notify(dev);
		}
		}

		if (have_flags)
		memcpy(nla_data(attr), &flags, sizeof(flags));
		/* Generate event to notify upper layer of bridge change */
		if (!err)
		err = rtnl_bridge_notify(dev, oflags);
		out:
		return err;
		}
		@@ -3049,15 +3043,18 @@ static int rtnl_bridge_dellink(struct sk_buff skb, struct nlmsghdr nlh)
		else
		err = dev->netdev_ops->ndo_bridge_dellink(dev, nlh);

		if (!err)
		if (!err) {
		flags &= ~BRIDGE_FLAGS_SELF;

		/* Generate event to notify upper layer of bridge
		* change
		*/
		err = rtnl_bridge_notify(dev);
		}
		}

		if (have_flags)
		memcpy(nla_data(attr), &flags, sizeof(flags));
		/* Generate event to notify upper layer of bridge change */
		if (!err)
		err = rtnl_bridge_notify(dev, oflags);
		out:
		return err;
		}

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