From 02dba4388d1691a087f40fe8acd2e1ffd577a07f Mon Sep 17 00:00:00 2001 From: Roopa Prabhu Date: Wed, 14 Jan 2015 20:02:25 -0800 Subject: [PATCH] bridge: fix setlink/dellink notifications 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 Signed-off-by: David S. Miller --- net/bridge/br_netlink.c | 5 +++++ net/core/rtnetlink.c | 45 +++++++++++++++++++---------------------- 2 files changed, 26 insertions(+), 24 deletions(-) diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 66ece91ee165..163950b10d8c 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -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; } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 6a6cdade1676..eadc5c0e2dfa 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -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; - } + 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; } -- 2.30.2