linux/include/net/rtnetlink.h
Xiao Liang 69c7be1b90 rtnetlink: Pack newlink() params into struct
There are 4 net namespaces involved when creating links:

 - source netns - where the netlink socket resides,
 - target netns - where to put the device being created,
 - link netns - netns associated with the device (backend),
 - peer netns - netns of peer device.

Currently, two nets are passed to newlink() callback - "src_net"
parameter and "dev_net" (implicitly in net_device). They are set as
follows, depending on netlink attributes in the request.

 +------------+-------------------+---------+---------+
 | peer netns | IFLA_LINK_NETNSID | src_net | dev_net |
 +------------+-------------------+---------+---------+
 |            | absent            | source  | target  |
 | absent     +-------------------+---------+---------+
 |            | present           | link    | link    |
 +------------+-------------------+---------+---------+
 |            | absent            | peer    | target  |
 | present    +-------------------+---------+---------+
 |            | present           | peer    | link    |
 +------------+-------------------+---------+---------+

When IFLA_LINK_NETNSID is present, the device is created in link netns
first and then moved to target netns. This has some side effects,
including extra ifindex allocation, ifname validation and link events.
These could be avoided if we create it in target netns from
the beginning.

On the other hand, the meaning of src_net parameter is ambiguous. It
varies depending on how parameters are passed. It is the effective
link (or peer netns) by design, but some drivers ignore it and use
dev_net instead.

To provide more netns context for drivers, this patch packs existing
newlink() parameters, along with the source netns, link netns and peer
netns, into a struct. The old "src_net" is renamed to "net" to avoid
confusion with real source netns, and will be deprecated later. The use
of src_net are converted to params->net trivially.

Signed-off-by: Xiao Liang <shaw.leon@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250219125039.18024-3-shaw.leon@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-21 15:28:02 -08:00

247 lines
8.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_RTNETLINK_H
#define __NET_RTNETLINK_H
#include <linux/rtnetlink.h>
#include <linux/srcu.h>
#include <net/netlink.h>
typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *,
struct netlink_ext_ack *);
typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *);
enum rtnl_link_flags {
RTNL_FLAG_DOIT_UNLOCKED = BIT(0),
#define RTNL_FLAG_DOIT_PERNET RTNL_FLAG_DOIT_UNLOCKED
#define RTNL_FLAG_DOIT_PERNET_WIP RTNL_FLAG_DOIT_UNLOCKED
RTNL_FLAG_BULK_DEL_SUPPORTED = BIT(1),
RTNL_FLAG_DUMP_UNLOCKED = BIT(2),
RTNL_FLAG_DUMP_SPLIT_NLM_DONE = BIT(3), /* legacy behavior */
};
enum rtnl_kinds {
RTNL_KIND_NEW,
RTNL_KIND_DEL,
RTNL_KIND_GET,
RTNL_KIND_SET
};
#define RTNL_KIND_MASK 0x3
static inline enum rtnl_kinds rtnl_msgtype_kind(int msgtype)
{
return msgtype & RTNL_KIND_MASK;
}
/**
* struct rtnl_msg_handler - rtnetlink message type and handlers
*
* @owner: NULL for built-in, THIS_MODULE for module
* @protocol: Protocol family or PF_UNSPEC
* @msgtype: rtnetlink message type
* @doit: Function pointer called for each request message
* @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message
* @flags: rtnl_link_flags to modify behaviour of doit/dumpit functions
*/
struct rtnl_msg_handler {
struct module *owner;
int protocol;
int msgtype;
rtnl_doit_func doit;
rtnl_dumpit_func dumpit;
int flags;
};
void rtnl_unregister_all(int protocol);
int __rtnl_register_many(const struct rtnl_msg_handler *handlers, int n);
void __rtnl_unregister_many(const struct rtnl_msg_handler *handlers, int n);
#define rtnl_register_many(handlers) \
__rtnl_register_many(handlers, ARRAY_SIZE(handlers))
#define rtnl_unregister_many(handlers) \
__rtnl_unregister_many(handlers, ARRAY_SIZE(handlers))
static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
{
if (nlmsg_len(nlh) >= sizeof(struct rtgenmsg))
return ((struct rtgenmsg *) nlmsg_data(nlh))->rtgen_family;
else
return AF_UNSPEC;
}
/**
* struct rtnl_newlink_params - parameters of rtnl_link_ops::newlink()
*
* @net: Netns of interest
* @src_net: Source netns of rtnetlink socket
* @link_net: Link netns by IFLA_LINK_NETNSID, NULL if not specified
* @peer_net: Peer netns
* @tb: IFLA_* attributes
* @data: IFLA_INFO_DATA attributes
*/
struct rtnl_newlink_params {
struct net *net;
struct net *src_net;
struct net *link_net;
struct net *peer_net;
struct nlattr **tb;
struct nlattr **data;
};
/**
* struct rtnl_link_ops - rtnetlink link operations
*
* @list: Used internally, protected by link_ops_mutex and SRCU
* @srcu: Used internally
* @kind: Identifier
* @netns_refund: Physical device, move to init_net on netns exit
* @peer_type: Peer device specific netlink attribute number (e.g. VETH_INFO_PEER)
* @maxtype: Highest device specific netlink attribute number
* @policy: Netlink policy for device specific attribute validation
* @validate: Optional validation function for netlink/changelink parameters
* @alloc: netdev allocation function, can be %NULL and is then used
* in place of alloc_netdev_mqs(), in this case @priv_size
* and @setup are unused. Returns a netdev or ERR_PTR().
* @priv_size: sizeof net_device private space
* @setup: net_device setup function
* @newlink: Function for configuring and registering a new device
* @changelink: Function for changing parameters of an existing device
* @dellink: Function to remove a device
* @get_size: Function to calculate required room for dumping device
* specific netlink attributes
* @fill_info: Function to dump device specific netlink attributes
* @get_xstats_size: Function to calculate required room for dumping device
* specific statistics
* @fill_xstats: Function to dump device specific statistics
* @get_num_tx_queues: Function to determine number of transmit queues
* to create when creating a new device.
* @get_num_rx_queues: Function to determine number of receive queues
* to create when creating a new device.
* @get_link_net: Function to get the i/o netns of the device
* @get_linkxstats_size: Function to calculate the required room for
* dumping device-specific extended link stats
* @fill_linkxstats: Function to dump device-specific extended link stats
*/
struct rtnl_link_ops {
struct list_head list;
struct srcu_struct srcu;
const char *kind;
size_t priv_size;
struct net_device *(*alloc)(struct nlattr *tb[],
const char *ifname,
unsigned char name_assign_type,
unsigned int num_tx_queues,
unsigned int num_rx_queues);
void (*setup)(struct net_device *dev);
bool netns_refund;
const u16 peer_type;
unsigned int maxtype;
const struct nla_policy *policy;
int (*validate)(struct nlattr *tb[],
struct nlattr *data[],
struct netlink_ext_ack *extack);
int (*newlink)(struct net_device *dev,
struct rtnl_newlink_params *params,
struct netlink_ext_ack *extack);
int (*changelink)(struct net_device *dev,
struct nlattr *tb[],
struct nlattr *data[],
struct netlink_ext_ack *extack);
void (*dellink)(struct net_device *dev,
struct list_head *head);
size_t (*get_size)(const struct net_device *dev);
int (*fill_info)(struct sk_buff *skb,
const struct net_device *dev);
size_t (*get_xstats_size)(const struct net_device *dev);
int (*fill_xstats)(struct sk_buff *skb,
const struct net_device *dev);
unsigned int (*get_num_tx_queues)(void);
unsigned int (*get_num_rx_queues)(void);
unsigned int slave_maxtype;
const struct nla_policy *slave_policy;
int (*slave_changelink)(struct net_device *dev,
struct net_device *slave_dev,
struct nlattr *tb[],
struct nlattr *data[],
struct netlink_ext_ack *extack);
size_t (*get_slave_size)(const struct net_device *dev,
const struct net_device *slave_dev);
int (*fill_slave_info)(struct sk_buff *skb,
const struct net_device *dev,
const struct net_device *slave_dev);
struct net *(*get_link_net)(const struct net_device *dev);
size_t (*get_linkxstats_size)(const struct net_device *dev,
int attr);
int (*fill_linkxstats)(struct sk_buff *skb,
const struct net_device *dev,
int *prividx, int attr);
};
int rtnl_link_register(struct rtnl_link_ops *ops);
void rtnl_link_unregister(struct rtnl_link_ops *ops);
/**
* struct rtnl_af_ops - rtnetlink address family operations
*
* @list: Used internally, protected by RTNL and SRCU
* @srcu: 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.
* @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;
struct srcu_struct srcu;
int family;
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,
u32 ext_filter_mask);
int (*validate_link_af)(const struct net_device *dev,
const struct nlattr *attr,
struct netlink_ext_ack *extack);
int (*set_link_af)(struct net_device *dev,
const struct nlattr *attr,
struct netlink_ext_ack *extack);
int (*fill_stats_af)(struct sk_buff *skb,
const struct net_device *dev);
size_t (*get_stats_af_size)(const struct net_device *dev);
};
int rtnl_af_register(struct rtnl_af_ops *ops);
void rtnl_af_unregister(struct rtnl_af_ops *ops);
struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]);
struct net_device *rtnl_create_link(struct net *net, const char *ifname,
unsigned char name_assign_type,
const struct rtnl_link_ops *ops,
struct nlattr *tb[],
struct netlink_ext_ack *extack);
int rtnl_delete_link(struct net_device *dev, u32 portid, const struct nlmsghdr *nlh);
int rtnl_configure_link(struct net_device *dev, const struct ifinfomsg *ifm,
u32 portid, const struct nlmsghdr *nlh);
int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer,
struct netlink_ext_ack *exterr);
struct net *rtnl_get_net_ns_capable(struct sock *sk, int netnsid);
#define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind)
#endif