strongswan/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.h

180 lines
4.6 KiB
C

/*
* Copyright (C) 2008-2020 Tobias Brunner
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#ifndef KERNEL_NETLINK_SHARED_H_
#define KERNEL_NETLINK_SHARED_H_
#include <library.h>
#include <linux/rtnetlink.h>
/**
* Default buffer size.
*
* 1024 byte is currently sufficient for all operations.
*/
#ifndef KERNEL_NETLINK_BUFSIZE
#define KERNEL_NETLINK_BUFSIZE 1024
#endif
/**
* General purpose netlink buffer.
*
* Some platforms require an enforced alignment to four bytes (e.g. ARM).
*/
typedef union {
struct nlmsghdr hdr;
u_char bytes[KERNEL_NETLINK_BUFSIZE];
} netlink_buf_t __attribute__((aligned(RTA_ALIGNTO)));
typedef struct netlink_socket_t netlink_socket_t;
/**
* Wrapper around a netlink socket.
*/
struct netlink_socket_t {
/**
* Send a netlink message and wait for a reply.
*
* @param in netlink message to send
* @param out received netlink message
* @param out_len length of the received message
*/
status_t (*send)(netlink_socket_t *this, struct nlmsghdr *in,
struct nlmsghdr **out, size_t *out_len);
/**
* Send a netlink message and wait for its acknowledge.
*
* @param in netlink message to send
*/
status_t (*send_ack)(netlink_socket_t *this, struct nlmsghdr *in);
/**
* Destroy the socket.
*/
void (*destroy)(netlink_socket_t *this);
};
/**
* Create a netlink_socket_t object.
*
* @param protocol protocol type (e.g. NETLINK_XFRM or NETLINK_ROUTE)
* @param names optional enum names for Netlink messages
* @param parallel support parallel queries on this Netlink socket
*/
netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names,
bool parallel);
/**
* Creates an rtattr and adds it to the given netlink message.
*
* @param hdr netlink message
* @param rta_type type of the rtattr
* @param data data to add to the rtattr
* @param buflen length of the netlink message buffer
*/
void netlink_add_attribute(struct nlmsghdr *hdr, int rta_type, chunk_t data,
size_t buflen);
/**
* Creates an rtattr under which other rtattrs are nested to the given netlink
* message.
*
* The returned pointer has to be passed to netlink_nested_end() after the
* nested attributes have been added to the message.
*
* @param hdr netlink message
* @param buflen size of full netlink buffer
* @param type RTA type
* @return attribute pointer
*/
void *netlink_nested_start(struct nlmsghdr *hdr, size_t buflen, int type);
/**
* Updates the length of the given attribute after nested attributes were added.
*
* @param hdr netlink message
* @param attr attribute returned from netlink_nested_start()
*/
void netlink_nested_end(struct nlmsghdr *hdr, void *attr);
/**
* Reserve space in a netlink message for given size and type, returning buffer.
*
* @param hdr netlink message
* @param buflen size of full netlink buffer
* @param type RTA type
* @param len length of RTA data
* @return buffer to len bytes of attribute data, NULL on error
*/
void* netlink_reserve(struct nlmsghdr *hdr, int buflen, int type, int len);
/**
* Determine buffer size for received messages (e.g. events).
*
* @return buffer size
*/
u_int netlink_get_buflen();
/**
* Information about an installed route.
*/
struct route_entry_t {
/** Destination net */
chunk_t dst_net;
/** Destination net prefix length */
uint8_t prefixlen;
/** Name of the interface the route is bound to (optional) */
char *if_name;
/** Source IP of the route (virtual IP or %any) */
host_t *src_ip;
/** Gateway for this route (optional) */
host_t *gateway;
/** Whether the route was installed for a passthrough policy */
bool pass;
};
typedef struct route_entry_t route_entry_t;
/**
* Destroy a route entry.
*/
void route_entry_destroy(route_entry_t *this);
/**
* Clone a route entry.
*/
route_entry_t *route_entry_clone(const route_entry_t *this);
/**
* Hash a route entry (note that this only hashes the destination).
*/
u_int route_entry_hash(const route_entry_t *this);
/**
* Compare two route entries.
*/
bool route_entry_equals(const route_entry_t *a, const route_entry_t *b);
#endif /* KERNEL_NETLINK_SHARED_H_ */