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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /net/l2tp/l2tp_core.h
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/l2tp/l2tp_core.h')
-rw-r--r--net/l2tp/l2tp_core.h346
1 files changed, 346 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
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+++ b/net/l2tp/l2tp_core.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/* L2TP internal definitions.
+ *
+ * Copyright (c) 2008,2009 Katalix Systems Ltd
+ */
+#include <linux/refcount.h>
+
+#ifndef _L2TP_CORE_H_
+#define _L2TP_CORE_H_
+
+#include <net/dst.h>
+#include <net/sock.h>
+
+#ifdef CONFIG_XFRM
+#include <net/xfrm.h>
+#endif
+
+/* 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 */
+#define L2TP_HASH_BITS 4
+#define L2TP_HASH_SIZE BIT(L2TP_HASH_BITS)
+
+/* System-wide session hash table size */
+#define L2TP_HASH_BITS_2 8
+#define L2TP_HASH_SIZE_2 BIT(L2TP_HASH_BITS_2)
+
+struct sk_buff;
+
+struct l2tp_stats {
+ atomic_long_t tx_packets;
+ atomic_long_t tx_bytes;
+ atomic_long_t tx_errors;
+ atomic_long_t rx_packets;
+ atomic_long_t rx_bytes;
+ atomic_long_t rx_seq_discards;
+ atomic_long_t rx_oos_packets;
+ atomic_long_t rx_errors;
+ atomic_long_t rx_cookie_discards;
+ atomic_long_t rx_invalid;
+};
+
+struct l2tp_tunnel;
+
+/* L2TP session configuration */
+struct l2tp_session_cfg {
+ enum l2tp_pwtype pw_type;
+ unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
+ unsigned int send_seq:1; /* send packets with sequence numbers? */
+ unsigned int lns_mode:1; /* behave as LNS?
+ * LAC enables sequence numbers under LNS control.
+ */
+ u16 l2specific_type; /* Layer 2 specific type */
+ u8 cookie[8]; /* optional cookie */
+ int cookie_len; /* 0, 4 or 8 bytes */
+ u8 peer_cookie[8]; /* peer's cookie */
+ int peer_cookie_len; /* 0, 4 or 8 bytes */
+ int reorder_timeout; /* configured reorder timeout (in jiffies) */
+ 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.
+ */
+#define L2TP_SESSION_NAME_MAX 32
+struct l2tp_session {
+ int magic; /* should be L2TP_SESSION_MAGIC */
+ long dead;
+
+ struct l2tp_tunnel *tunnel; /* back pointer to tunnel context */
+ u32 session_id;
+ u32 peer_session_id;
+ u8 cookie[8];
+ int cookie_len;
+ u8 peer_cookie[8];
+ int peer_cookie_len;
+ u16 l2specific_type;
+ u16 hdr_len;
+ u32 nr; /* session NR state (receive) */
+ u32 ns; /* session NR state (send) */
+ struct sk_buff_head reorder_q; /* receive reorder queue */
+ u32 nr_max; /* max NR. Depends on tunnel */
+ u32 nr_window_size; /* NR window size */
+ u32 nr_oos; /* NR of last OOS packet */
+ int nr_oos_count; /* for OOS recovery */
+ int nr_oos_count_max;
+ struct hlist_node hlist; /* hash list node */
+ refcount_t ref_count;
+
+ char name[L2TP_SESSION_NAME_MAX]; /* for logging */
+ char ifname[IFNAMSIZ];
+ unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
+ unsigned int send_seq:1; /* send packets with sequence numbers? */
+ unsigned int lns_mode:1; /* behave as LNS?
+ * LAC enables sequence numbers under LNS control.
+ */
+ int reorder_timeout; /* configured reorder timeout (in jiffies) */
+ int reorder_skip; /* set if skip to next nr */
+ enum l2tp_pwtype pwtype;
+ struct l2tp_stats stats;
+ struct hlist_node global_hlist; /* global hash list node */
+
+ /* 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 */
+};
+
+/* L2TP tunnel configuration */
+struct l2tp_tunnel_cfg {
+ enum l2tp_encap_type encap;
+
+ /* Used only for kernel-created sockets */
+ struct in_addr local_ip;
+ struct in_addr peer_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+ struct in6_addr *local_ip6;
+ struct in6_addr *peer_ip6;
+#endif
+ u16 local_udp_port;
+ u16 peer_udp_port;
+ unsigned int use_udp_checksums:1,
+ udp6_zero_tx_checksums:1,
+ 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.
+ */
+#define L2TP_TUNNEL_NAME_MAX 20
+struct l2tp_tunnel {
+ int magic; /* Should be L2TP_TUNNEL_MAGIC */
+
+ unsigned long dead;
+
+ struct rcu_head rcu;
+ spinlock_t hlist_lock; /* write-protection for session_hlist */
+ bool acpt_newsess; /* indicates whether this tunnel accepts
+ * new sessions. Protected by hlist_lock.
+ */
+ struct hlist_head session_hlist[L2TP_HASH_SIZE];
+ /* hashed list of sessions, hashed by id */
+ u32 tunnel_id;
+ u32 peer_tunnel_id;
+ int version; /* 2=>L2TPv2, 3=>L2TPv3 */
+
+ char name[L2TP_TUNNEL_NAME_MAX]; /* for logging */
+ enum l2tp_encap_type encap;
+ struct l2tp_stats stats;
+
+ struct list_head list; /* list node on per-namespace list of tunnels */
+ struct net *l2tp_net; /* the net we belong to */
+
+ refcount_t ref_count;
+ void (*old_sk_destruct)(struct sock *sk);
+ struct sock *sock; /* parent socket */
+ int fd; /* parent fd, if tunnel socket was created
+ * by userspace
+ */
+
+ 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);
+
+ /* 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)
+{
+ 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);
+
+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(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);
+
+/* 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);
+
+/* 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);
+
+/* Pseudowire management.
+ * Pseudowires should register with l2tp core on module init, and unregister
+ * on module exit.
+ */
+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);
+
+/* IOCTL helper for IP encap modules. */
+int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
+
+/* Extract the tunnel structure from a socket's sk_user_data pointer,
+ * validating the tunnel magic feather.
+ */
+struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk);
+
+static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
+{
+ switch (session->l2specific_type) {
+ case L2TP_L2SPECTYPE_DEFAULT:
+ return 4;
+ case L2TP_L2SPECTYPE_NONE:
+ default:
+ return 0;
+ }
+}
+
+static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel)
+{
+ struct dst_entry *dst;
+ u32 mtu;
+
+ dst = sk_dst_get(tunnel->sock);
+ if (!dst)
+ return 0;
+
+ mtu = dst_mtu(dst);
+ dst_release(dst);
+
+ return mtu;
+}
+
+#ifdef CONFIG_XFRM
+static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
+{
+ struct sock *sk = tunnel->sock;
+
+ return sk && (rcu_access_pointer(sk->sk_policy[0]) ||
+ rcu_access_pointer(sk->sk_policy[1]));
+}
+#else
+static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
+{
+ return false;
+}
+#endif
+
+static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb,
+ unsigned char **ptr, unsigned char **optr)
+{
+ int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session);
+
+ if (opt_len > 0) {
+ int off = *ptr - *optr;
+
+ if (!pskb_may_pull(skb, off + opt_len))
+ return -1;
+
+ if (skb->data != *optr) {
+ *optr = skb->data;
+ *ptr = skb->data + off;
+ }
+ }
+
+ return 0;
+}
+
+#define MODULE_ALIAS_L2TP_PWTYPE(type) \
+ MODULE_ALIAS("net-l2tp-type-" __stringify(type))
+
+#endif /* _L2TP_CORE_H_ */