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|
#ifndef _NET_XFRM_H
#define _NET_XFRM_H
#include <linux/compiler.h>
#include <linux/in.h>
#include <linux/xfrm.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/pfkeyv2.h>
#include <linux/ipsec.h>
#include <linux/in6.h>
#include <linux/mutex.h>
#include <net/sock.h>
#include <net/dst.h>
#include <net/route.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#define XFRM_ALIGN8(len) (((len) + 7) & ~7)
#define MODULE_ALIAS_XFRM_MODE(family, encap) \
MODULE_ALIAS("xfrm-mode-" __stringify(family) "-" __stringify(encap))
extern struct sock *xfrm_nl;
extern u32 sysctl_xfrm_aevent_etime;
extern u32 sysctl_xfrm_aevent_rseqth;
extern struct mutex xfrm_cfg_mutex;
/* Organization of SPD aka "XFRM rules"
------------------------------------
Basic objects:
- policy rule, struct xfrm_policy (=SPD entry)
- bundle of transformations, struct dst_entry == struct xfrm_dst (=SA bundle)
- instance of a transformer, struct xfrm_state (=SA)
- template to clone xfrm_state, struct xfrm_tmpl
SPD is plain linear list of xfrm_policy rules, ordered by priority.
(To be compatible with existing pfkeyv2 implementations,
many rules with priority of 0x7fffffff are allowed to exist and
such rules are ordered in an unpredictable way, thanks to bsd folks.)
Lookup is plain linear search until the first match with selector.
If "action" is "block", then we prohibit the flow, otherwise:
if "xfrms_nr" is zero, the flow passes untransformed. Otherwise,
policy entry has list of up to XFRM_MAX_DEPTH transformations,
described by templates xfrm_tmpl. Each template is resolved
to a complete xfrm_state (see below) and we pack bundle of transformations
to a dst_entry returned to requestor.
dst -. xfrm .-> xfrm_state #1
|---. child .-> dst -. xfrm .-> xfrm_state #2
|---. child .-> dst -. xfrm .-> xfrm_state #3
|---. child .-> NULL
Bundles are cached at xrfm_policy struct (field ->bundles).
Resolution of xrfm_tmpl
-----------------------
Template contains:
1. ->mode Mode: transport or tunnel
2. ->id.proto Protocol: AH/ESP/IPCOMP
3. ->id.daddr Remote tunnel endpoint, ignored for transport mode.
Q: allow to resolve security gateway?
4. ->id.spi If not zero, static SPI.
5. ->saddr Local tunnel endpoint, ignored for transport mode.
6. ->algos List of allowed algos. Plain bitmask now.
Q: ealgos, aalgos, calgos. What a mess...
7. ->share Sharing mode.
Q: how to implement private sharing mode? To add struct sock* to
flow id?
Having this template we search through SAD searching for entries
with appropriate mode/proto/algo, permitted by selector.
If no appropriate entry found, it is requested from key manager.
PROBLEMS:
Q: How to find all the bundles referring to a physical path for
PMTU discovery? Seems, dst should contain list of all parents...
and enter to infinite locking hierarchy disaster.
No! It is easier, we will not search for them, let them find us.
We add genid to each dst plus pointer to genid of raw IP route,
pmtu disc will update pmtu on raw IP route and increase its genid.
dst_check() will see this for top level and trigger resyncing
metrics. Plus, it will be made via sk->sk_dst_cache. Solved.
*/
/* Full description of state of transformer. */
struct xfrm_state
{
/* Note: bydst is re-used during gc */
struct hlist_node bydst;
struct hlist_node bysrc;
struct hlist_node byspi;
atomic_t refcnt;
spinlock_t lock;
struct xfrm_id id;
struct xfrm_selector sel;
u32 genid;
/* Key manger bits */
struct {
u8 state;
u8 dying;
u32 seq;
} km;
/* Parameters of this state. */
struct {
u32 reqid;
u8 mode;
u8 replay_window;
u8 aalgo, ealgo, calgo;
u8 flags;
u16 family;
xfrm_address_t saddr;
int header_len;
int trailer_len;
} props;
struct xfrm_lifetime_cfg lft;
/* Data for transformer */
struct xfrm_algo *aalg;
struct xfrm_algo *ealg;
struct xfrm_algo *calg;
/* Data for encapsulator */
struct xfrm_encap_tmpl *encap;
/* Data for care-of address */
xfrm_address_t *coaddr;
/* IPComp needs an IPIP tunnel for handling uncompressed packets */
struct xfrm_state *tunnel;
/* If a tunnel, number of users + 1 */
atomic_t tunnel_users;
/* State for replay detection */
struct xfrm_replay_state replay;
/* Replay detection state at the time we sent the last notification */
struct xfrm_replay_state preplay;
/* internal flag that only holds state for delayed aevent at the
* moment
*/
u32 xflags;
/* Replay detection notification settings */
u32 replay_maxage;
u32 replay_maxdiff;
/* Replay detection notification timer */
struct timer_list rtimer;
/* Statistics */
struct xfrm_stats stats;
struct xfrm_lifetime_cur curlft;
struct timer_list timer;
/* Last used time */
u64 lastused;
/* Reference to data common to all the instances of this
* transformer. */
struct xfrm_type *type;
struct xfrm_mode *mode;
/* Security context */
struct xfrm_sec_ctx *security;
/* Private data of this transformer, format is opaque,
* interpreted by xfrm_type methods. */
void *data;
};
/* xflags - make enum if more show up */
#define XFRM_TIME_DEFER 1
enum {
XFRM_STATE_VOID,
XFRM_STATE_ACQ,
XFRM_STATE_VALID,
XFRM_STATE_ERROR,
XFRM_STATE_EXPIRED,
XFRM_STATE_DEAD
};
/* callback structure passed from either netlink or pfkey */
struct km_event
{
union {
u32 hard;
u32 proto;
u32 byid;
u32 aevent;
u32 type;
} data;
u32 seq;
u32 pid;
u32 event;
};
struct xfrm_type;
struct xfrm_dst;
struct xfrm_policy_afinfo {
unsigned short family;
struct xfrm_type *type_map[IPPROTO_MAX];
struct xfrm_mode *mode_map[XFRM_MODE_MAX];
struct dst_ops *dst_ops;
void (*garbage_collect)(void);
int (*dst_lookup)(struct xfrm_dst **dst, struct flowi *fl);
int (*get_saddr)(xfrm_address_t *saddr, xfrm_address_t
|