From f8ff182c716c6f11ca3061961f5722f26a14e101 Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 16 Nov 2010 04:30:14 +0000 Subject: rtnetlink: Link address family API Each net_device contains address family specific data such as per device settings and statistics. We already expose this data via procfs/sysfs and partially netlink. The netlink method requires the requester to send one RTM_GETLINK request for each address family it wishes to receive data of and then merge this data itself. This patch implements a new API which combines all address family specific link data in a new netlink attribute IFLA_AF_SPEC. IFLA_AF_SPEC contains a sequence of nested attributes, one for each address family which in turn defines the structure of its own attribute. Example: [IFLA_AF_SPEC] = { [AF_INET] = { [IFLA_INET_CONF] = ..., }, [AF_INET6] = { [IFLA_INET6_FLAGS] = ..., [IFLA_INET6_CONF] = ..., } } The API also allows for address families to implement a function which parses the IFLA_AF_SPEC attribute sent by userspace to implement address family specific link options. Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/net/rtnetlink.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'include/net/rtnetlink.h') diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index e013c68bfb00..35be0bbcd7da 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -83,6 +83,37 @@ extern void __rtnl_link_unregister(struct rtnl_link_ops *ops); extern int rtnl_link_register(struct rtnl_link_ops *ops); extern void rtnl_link_unregister(struct rtnl_link_ops *ops); +/** + * struct rtnl_af_ops - rtnetlink address family operations + * + * @list: Used internally + * @family: Address family + * @fill_link_af: Function to fill IFLA_AF_SPEC with address family + * specific netlink attributes. + * @get_link_af_size: Function to calculate size of address family specific + * netlink attributes exlusive the container attribute. + * @parse_link_af: Function to parse a IFLA_AF_SPEC attribute and modify + * net_device accordingly. + */ +struct rtnl_af_ops { + struct list_head list; + int family; + + int (*fill_link_af)(struct sk_buff *skb, + const struct net_device *dev); + size_t (*get_link_af_size)(const struct net_device *dev); + + int (*parse_link_af)(struct net_device *dev, + const struct nlattr *attr); +}; + +extern int __rtnl_af_register(struct rtnl_af_ops *ops); +extern void __rtnl_af_unregister(struct rtnl_af_ops *ops); + +extern int rtnl_af_register(struct rtnl_af_ops *ops); +extern void rtnl_af_unregister(struct rtnl_af_ops *ops); + + extern struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]); extern struct net_device *rtnl_create_link(struct net *src_net, struct net *net, char *ifname, const struct rtnl_link_ops *ops, struct nlattr *tb[]); -- cgit v1.2.2 From cf7afbfeb8ceb0187348d0a1a0db61305e25f05f Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Mon, 22 Nov 2010 01:31:54 +0000 Subject: rtnl: make link af-specific updates atomic As David pointed out correctly, updates to af-specific attributes are currently not atomic. If multiple changes are requested and one of them fails, previous updates may have been applied already leaving the link behind in a undefined state. This patch splits the function parse_link_af() into two functions validate_link_af() and set_link_at(). validate_link_af() is placed to validate_linkmsg() check for errors as early as possible before any changes to the link have been made. set_link_af() is called to commit the changes later. This method is not fail proof, while it is currently sufficient to make set_link_af() inerrable and thus 100% atomic, the validation function method will not be able to detect all error scenarios in the future, there will likely always be errors depending on states which are f.e. not protected by rtnl_mutex and thus may change between validation and setting. Also, instead of silently ignoring unknown address families and config blocks for address families which did not register a set function the errors EAFNOSUPPORT respectively EOPNOSUPPORT are returned to avoid comitting 4 out of 5 update requests without notifying the user. Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/net/rtnetlink.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'include/net/rtnetlink.h') diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index 35be0bbcd7da..4093ca78cf60 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -92,8 +92,10 @@ extern void rtnl_link_unregister(struct rtnl_link_ops *ops); * specific netlink attributes. * @get_link_af_size: Function to calculate size of address family specific * netlink attributes exlusive the container attribute. - * @parse_link_af: Function to parse a IFLA_AF_SPEC attribute and modify - * net_device accordingly. + * @validate_link_af: Validate a IFLA_AF_SPEC attribute, must check attr + * for invalid configuration settings. + * @set_link_af: Function to parse a IFLA_AF_SPEC attribute and modify + * net_device accordingly. */ struct rtnl_af_ops { struct list_head list; @@ -103,8 +105,10 @@ struct rtnl_af_ops { const struct net_device *dev); size_t (*get_link_af_size)(const struct net_device *dev); - int (*parse_link_af)(struct net_device *dev, - const struct nlattr *attr); + int (*validate_link_af)(const struct net_device *dev, + const struct nlattr *attr); + int (*set_link_af)(struct net_device *dev, + const struct nlattr *attr); }; extern int __rtnl_af_register(struct rtnl_af_ops *ops); -- cgit v1.2.2