Commit b1974ed0 authored by Arad, Ronen's avatar Arad, Ronen Committed by David S. Miller
Browse files

netlink: Rightsize IFLA_AF_SPEC size calculation 



if_nlmsg_size() overestimates the minimum allocation size of netlink
dump request (when called from rtnl_calcit()) or the size of the
message (when called from rtnl_getlink()). This is because
ext_filter_mask is not supported by rtnl_link_get_af_size() and
rtnl_link_get_size().

The over-estimation is significant when at least one netdev has many
VLANs configured (8 bytes for each configured VLAN).

This patch-set "rightsizes" the protocol specific attribute size
calculation by propagating ext_filter_mask to rtnl_link_get_af_size()
and adding this a argument to get_link_af_size op in rtnl_af_ops.

Bridge module already used filtering aware sizing for notifications.
br_get_link_af_size_filtered() is consistent with the modified
get_link_af_size op so it replaces br_get_link_af_size() in br_af_ops.
br_get_link_af_size() becomes unused and thus removed.

Signed-off-by: default avatarRonen Arad <ronen.arad@intel.com>
Acked-by: default avatarSridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6ac311ae

include/net/rtnetlink.h

+2 −1
Original line number Diff line number Diff line
@@ -124,7 +124,8 @@ struct rtnl_af_ops { 
	int			(*fill_link_af)(struct sk_buff *skb,

						const struct net_device *dev,

						u32 ext_filter_mask);

	size_t			(*get_link_af_size)(const struct net_device *dev);

	size_t			(*get_link_af_size)(const struct net_device *dev,

						    u32 ext_filter_mask);



	int			(*validate_link_af)(const struct net_device *dev,

						    const struct nlattr *attr);

net/bridge/br_netlink.c

+1 −20
Original line number Diff line number Diff line
@@ -1214,29 +1214,10 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev) 
	return 0;

}



static size_t br_get_link_af_size(const struct net_device *dev)

{

	struct net_bridge_port *p;

	struct net_bridge *br;

	int num_vlans = 0;



	if (br_port_exists(dev)) {

		p = br_port_get_rtnl(dev);

		num_vlans = br_get_num_vlan_infos(nbp_vlan_group(p),

						  RTEXT_FILTER_BRVLAN);

	} else if (dev->priv_flags & IFF_EBRIDGE) {

		br = netdev_priv(dev);

		num_vlans = br_get_num_vlan_infos(br_vlan_group(br),

						  RTEXT_FILTER_BRVLAN);

	}



	/* Each VLAN is returned in bridge_vlan_info along with flags */

	return num_vlans * nla_total_size(sizeof(struct bridge_vlan_info));

}



static struct rtnl_af_ops br_af_ops __read_mostly = {

	.family			= AF_BRIDGE,

	.get_link_af_size	= br_get_link_af_size,

	.get_link_af_size	= br_get_link_af_size_filtered,

};



struct rtnl_link_ops br_link_ops __read_mostly = {

net/core/rtnetlink.c

+4 −4
Original line number Diff line number Diff line
@@ -497,7 +497,8 @@ void rtnl_af_unregister(struct rtnl_af_ops *ops) 
}

EXPORT_SYMBOL_GPL(rtnl_af_unregister);



static size_t rtnl_link_get_af_size(const struct net_device *dev)

static size_t rtnl_link_get_af_size(const struct net_device *dev,

				    u32 ext_filter_mask)

{

	struct rtnl_af_ops *af_ops;

	size_t size;
@@ -509,7 +510,7 @@ static size_t rtnl_link_get_af_size(const struct net_device *dev) 
		if (af_ops->get_link_af_size) {

			/* AF_* + nested data */

			size += nla_total_size(sizeof(struct nlattr)) +

				af_ops->get_link_af_size(dev);

				af_ops->get_link_af_size(dev, ext_filter_mask);

		}

	}
@@ -900,7 +901,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, 
	       + rtnl_vfinfo_size(dev, ext_filter_mask) /* IFLA_VFINFO_LIST */

	       + rtnl_port_size(dev, ext_filter_mask) /* IFLA_VF_PORTS + IFLA_PORT_SELF */

	       + rtnl_link_get_size(dev) /* IFLA_LINKINFO */

	       + rtnl_link_get_af_size(dev) /* IFLA_AF_SPEC */

	       + rtnl_link_get_af_size(dev, ext_filter_mask) /* IFLA_AF_SPEC */

	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_PORT_ID */

	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_SWITCH_ID */

	       + nla_total_size(1); /* IFLA_PROTO_DOWN */
@@ -3443,4 +3444,3 @@ void __init rtnetlink_init(void) 
	rtnl_register(PF_BRIDGE, RTM_DELLINK, rtnl_bridge_dellink, NULL, NULL);

	rtnl_register(PF_BRIDGE, RTM_SETLINK, rtnl_bridge_setlink, NULL, NULL);

}

net/ipv4/devinet.c

+2 −2
Original line number Diff line number Diff line
@@ -1644,7 +1644,8 @@ errout: 
		rtnl_set_sk_err(net, RTNLGRP_IPV4_IFADDR, err);

}



static size_t inet_get_link_af_size(const struct net_device *dev)

static size_t inet_get_link_af_size(const struct net_device *dev,

				    u32 ext_filter_mask)

{

	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
@@ -2398,4 +2399,3 @@ void __init devinet_init(void) 
	rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,

		      inet_netconf_dump_devconf, NULL);

}

net/ipv6/addrconf.c

+2 −1
Original line number Diff line number Diff line
@@ -4788,7 +4788,8 @@ nla_put_failure: 
	return -EMSGSIZE;

}



static size_t inet6_get_link_af_size(const struct net_device *dev)

static size_t inet6_get_link_af_size(const struct net_device *dev,

				     u32 ext_filter_mask)

{

	if (!__in6_dev_get(dev))

		return 0;

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