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Merge branch 'l2tp-tidy-up-l2tp-core-API'

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Tom Parkin says:

====================
l2tp: tidy up l2tp core API

This short series makes some minor tidyup changes to the L2TP core API.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2020-07-30 16:45:31 -07:00
commit 2a043e9cec
4 changed files with 154 additions and 111 deletions
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138
net/l2tp/l2tp_core.c
View file

@ -149,12 +149,51 @@ l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
}
void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
{
sock_put(tunnel->sock);
/* the tunnel is freed in the socket destructor */
}
EXPORT_SYMBOL(l2tp_tunnel_free);
static void l2tp_session_free(struct l2tp_session *session)
{
struct l2tp_tunnel *tunnel = session->tunnel;
if (tunnel) {
if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))
goto out;
l2tp_tunnel_dec_refcount(tunnel);
}
out:
kfree(session);
}
void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
{
refcount_inc(&tunnel->ref_count);
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_inc_refcount);
void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
{
if (refcount_dec_and_test(&tunnel->ref_count))
l2tp_tunnel_free(tunnel);
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_dec_refcount);
void l2tp_session_inc_refcount(struct l2tp_session *session)
{
refcount_inc(&session->ref_count);
}
EXPORT_SYMBOL_GPL(l2tp_session_inc_refcount);
void l2tp_session_dec_refcount(struct l2tp_session *session)
{
if (refcount_dec_and_test(&session->ref_count))
l2tp_session_free(session);
}
EXPORT_SYMBOL_GPL(l2tp_session_dec_refcount);
/* Lookup a tunnel. A new reference is held on the returned tunnel. */
struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
@ -769,7 +808,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
atomic_long_inc(&session->stats.rx_errors);
kfree_skb(skb);
}
EXPORT_SYMBOL(l2tp_recv_common);
EXPORT_SYMBOL_GPL(l2tp_recv_common);
/* Drop skbs from the session's reorder_q
*/
@ -1077,7 +1116,10 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
}
/* Setup L2TP header */
session->build_header(session, __skb_push(skb, hdr_len));
if (tunnel->version == L2TP_HDR_VER_2)
l2tp_build_l2tpv2_header(session, __skb_push(skb, hdr_len));
else
l2tp_build_l2tpv3_header(session, __skb_push(skb, hdr_len));
/* Reset skb netfilter state */
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@ -1180,6 +1222,30 @@ static void l2tp_tunnel_destruct(struct sock *sk)
return;
}
/* Remove an l2tp session from l2tp_core's hash lists. */
static void l2tp_session_unhash(struct l2tp_session *session)
{
struct l2tp_tunnel *tunnel = session->tunnel;
/* Remove the session from core hashes */
if (tunnel) {
/* Remove from the per-tunnel hash */
write_lock_bh(&tunnel->hlist_lock);
hlist_del_init(&session->hlist);
write_unlock_bh(&tunnel->hlist_lock);
/* For L2TPv3 we have a per-net hash: remove from there, too */
if (tunnel->version != L2TP_HDR_VER_2) {
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
spin_lock_bh(&pn->l2tp_session_hlist_lock);
hlist_del_init_rcu(&session->global_hlist);
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
synchronize_rcu();
}
}
}
/* When the tunnel is closed, all the attached sessions need to go too.
*/
static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
@ -1209,7 +1275,7 @@ static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
write_unlock_bh(&tunnel->hlist_lock);
__l2tp_session_unhash(session);
l2tp_session_unhash(session);
l2tp_session_queue_purge(session);
if (session->session_close)
@ -1557,68 +1623,17 @@ void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
/* Really kill the session.
*/
void l2tp_session_free(struct l2tp_session *session)
{
struct l2tp_tunnel *tunnel = session->tunnel;
if (tunnel) {
if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))
goto out;
l2tp_tunnel_dec_refcount(tunnel);
}
out:
kfree(session);
}
EXPORT_SYMBOL_GPL(l2tp_session_free);
/* Remove an l2tp session from l2tp_core's hash lists.
* Provides a tidyup interface for pseudowire code which can't just route all
* shutdown via. l2tp_session_delete and a pseudowire-specific session_close
* callback.
*/
void __l2tp_session_unhash(struct l2tp_session *session)
{
struct l2tp_tunnel *tunnel = session->tunnel;
/* Remove the session from core hashes */
if (tunnel) {
/* Remove from the per-tunnel hash */
write_lock_bh(&tunnel->hlist_lock);
hlist_del_init(&session->hlist);
write_unlock_bh(&tunnel->hlist_lock);
/* For L2TPv3 we have a per-net hash: remove from there, too */
if (tunnel->version != L2TP_HDR_VER_2) {
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
spin_lock_bh(&pn->l2tp_session_hlist_lock);
hlist_del_init_rcu(&session->global_hlist);
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
synchronize_rcu();
}
}
}
EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
/* This function is used by the netlink SESSION_DELETE command and by
* pseudowire modules.
*/
int l2tp_session_delete(struct l2tp_session *session)
void l2tp_session_delete(struct l2tp_session *session)
{
if (test_and_set_bit(0, &session->dead))
return 0;
return;
__l2tp_session_unhash(session);
l2tp_session_unhash(session);
l2tp_session_queue_purge(session);
if (session->session_close)
(*session->session_close)(session);
l2tp_session_dec_refcount(session);
return 0;
}
EXPORT_SYMBOL_GPL(l2tp_session_delete);
@ -1688,11 +1703,6 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
}
if (tunnel->version == L2TP_HDR_VER_2)
session->build_header = l2tp_build_l2tpv2_header;
else
session->build_header = l2tp_build_l2tpv3_header;
l2tp_session_set_header_len(session, tunnel->version);
refcount_set(&session->ref_count, 1);

123
net/l2tp/l2tp_core.h
View file

@ -15,15 +15,15 @@
#include <net/xfrm.h>
#endif
/* Just some random numbers */
/* Random numbers used for internal consistency checks of tunnel and session structures */
#define L2TP_TUNNEL_MAGIC 0x42114DDA
#define L2TP_SESSION_MAGIC 0x0C04EB7D
/* Per tunnel, session hash table size */
/* Per tunnel session hash table size */
#define L2TP_HASH_BITS 4
#define L2TP_HASH_SIZE BIT(L2TP_HASH_BITS)
/* System-wide, session hash table size */
/* System-wide session hash table size */
#define L2TP_HASH_BITS_2 8
#define L2TP_HASH_SIZE_2 BIT(L2TP_HASH_BITS_2)
@ -43,9 +43,7 @@ struct l2tp_stats {
struct l2tp_tunnel;
/* Describes a session. Contains information to determine incoming
* packets and transmit outgoing ones.
*/
/* L2TP session configuration */
struct l2tp_session_cfg {
enum l2tp_pwtype pw_type;
unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
@ -63,6 +61,11 @@ struct l2tp_session_cfg {
char *ifname;
};
/* Represents a session (pseudowire) instance.
* Tracks runtime state including cookies, dataplane packet sequencing, and IO statistics.
* Is linked into a per-tunnel session hashlist; and in the case of an L2TPv3 session into
* an additional per-net ("global") hashlist.
*/
struct l2tp_session {
int magic; /* should be L2TP_SESSION_MAGIC */
long dead;
@ -101,16 +104,32 @@ struct l2tp_session {
struct l2tp_stats stats;
struct hlist_node global_hlist; /* global hash list node */
int (*build_header)(struct l2tp_session *session, void *buf);
/* Session receive handler for data packets.
* Each pseudowire implementation should implement this callback in order to
* handle incoming packets. Packets are passed to the pseudowire handler after
* reordering, if data sequence numbers are enabled for the session.
*/
void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
/* Session close handler.
* Each pseudowire implementation may implement this callback in order to carry
* out pseudowire-specific shutdown actions.
* The callback is called by core after unhashing the session and purging its
* reorder queue.
*/
void (*session_close)(struct l2tp_session *session);
/* Session show handler.
* Pseudowire-specific implementation of debugfs session rendering.
* The callback is called by l2tp_debugfs.c after rendering core session
* information.
*/
void (*show)(struct seq_file *m, void *priv);
u8 priv[]; /* private data */
};
/* Describes the tunnel. It contains info to track all the associated
* sessions so incoming packets can be sorted out
*/
/* L2TP tunnel configuration */
struct l2tp_tunnel_cfg {
int debug; /* bitmask of debug message categories */
enum l2tp_encap_type encap;
@ -129,6 +148,12 @@ struct l2tp_tunnel_cfg {
udp6_zero_rx_checksums:1;
};
/* Represents a tunnel instance.
* Tracks runtime state including IO statistics.
* Holds the tunnel socket (either passed from userspace or directly created by the kernel).
* Maintains a hashlist of sessions belonging to the tunnel instance.
* Is linked into a per-net list of tunnels.
*/
struct l2tp_tunnel {
int magic; /* Should be L2TP_TUNNEL_MAGIC */
@ -163,11 +188,24 @@ struct l2tp_tunnel {
struct work_struct del_work;
};
/* Pseudowire ops callbacks for use with the l2tp genetlink interface */
struct l2tp_nl_cmd_ops {
/* The pseudowire session create callback is responsible for creating a session
* instance for a specific pseudowire type.
* It must call l2tp_session_create and l2tp_session_register to register the
* session instance, as well as carry out any pseudowire-specific initialisation.
* It must return >= 0 on success, or an appropriate negative errno value on failure.
*/
int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
u32 session_id, u32 peer_session_id,
struct l2tp_session_cfg *cfg);
int (*session_delete)(struct l2tp_session *session);
/* The pseudowire session delete callback is responsible for initiating the deletion
* of a session instance.
* It must call l2tp_session_delete, as well as carry out any pseudowire-specific
* teardown actions.
*/
void (*session_delete)(struct l2tp_session *session);
};
static inline void *l2tp_session_priv(struct l2tp_session *session)
@ -175,73 +213,68 @@ static inline void *l2tp_session_priv(struct l2tp_session *session)
return &session->priv[0];
}
/* Tunnel and session refcounts */
void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel);
void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel);
void l2tp_session_inc_refcount(struct l2tp_session *session);
void l2tp_session_dec_refcount(struct l2tp_session *session);
/* Tunnel and session lookup.
* These functions take a reference on the instances they return, so
* the caller must ensure that the reference is dropped appropriately.
*/
struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
u32 session_id);
void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id);
struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
const char *ifname);
/* Tunnel and session lifetime management.
* Creation of a new instance is a two-step process: create, then register.
* Destruction is triggered using the *_delete functions, and completes asynchronously.
*/
int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
struct l2tp_tunnel **tunnelp);
int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
struct l2tp_tunnel_cfg *cfg);
void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
struct l2tp_session *l2tp_session_create(int priv_size,
struct l2tp_tunnel *tunnel,
u32 session_id, u32 peer_session_id,
struct l2tp_session_cfg *cfg);
int l2tp_session_register(struct l2tp_session *session,
struct l2tp_tunnel *tunnel);
void l2tp_session_delete(struct l2tp_session *session);
void __l2tp_session_unhash(struct l2tp_session *session);
int l2tp_session_delete(struct l2tp_session *session);
void l2tp_session_free(struct l2tp_session *session);
/* Receive path helpers. If data sequencing is enabled for the session these
* functions handle queuing and reordering prior to passing packets to the
* pseudowire code to be passed to userspace.
*/
void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
unsigned char *ptr, unsigned char *optr, u16 hdrflags,
int length);
int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
void l2tp_session_set_header_len(struct l2tp_session *session, int version);
/* Transmit path helpers for sending packets over the tunnel socket. */
void l2tp_session_set_header_len(struct l2tp_session *session, int version);
int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
int hdr_len);
int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
const struct l2tp_nl_cmd_ops *ops);
void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
{
refcount_inc(&tunnel->ref_count);
}
static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
{
if (refcount_dec_and_test(&tunnel->ref_count))
l2tp_tunnel_free(tunnel);
}
/* Session reference counts. Incremented when code obtains a reference
* to a session.
/* Pseudowire management.
* Pseudowires should register with l2tp core on module init, and unregister
* on module exit.
*/
static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
{
refcount_inc(&session->ref_count);
}
int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
{
if (refcount_dec_and_test(&session->ref_count))
l2tp_session_free(session);
}
/* IOCTL helper for IP encap modules. */
int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
{

2
net/l2tp/l2tp_ip.c
View file

@ -597,7 +597,7 @@ int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
return put_user(amount, (int __user *)arg);
}
EXPORT_SYMBOL(l2tp_ioctl);
EXPORT_SYMBOL_GPL(l2tp_ioctl);
static struct proto l2tp_ip_prot = {
.name = "L2TP/IP",

2
net/l2tp/l2tp_netlink.c
View file

@ -670,7 +670,7 @@ static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *inf
pw_type = session->pwtype;
if (pw_type < __L2TP_PWTYPE_MAX)
if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
l2tp_nl_cmd_ops[pw_type]->session_delete(session);
l2tp_session_dec_refcount(session);