20  * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
30  * over an L2TP session:-
113 /* Private data of each session. This data lives at the end of struct
114  * l2tp_session, referenced via session->priv[].
120 	struct sock __rcu	*sk;		/* Pointer to the session PPPoX socket */
132 /* Retrieves the pppol2tp socket associated to a session. */
133 static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session)  in pppol2tp_session_get_sock()  argument
135 	struct pppol2tp_session *ps = l2tp_session_priv(session);  in pppol2tp_session_get_sock()
140 /* Helpers to obtain tunnel/session contexts from sockets.
144 	struct l2tp_session *session;  in pppol2tp_sock_to_session()  local
150 	session = rcu_dereference_sk_user_data(sk);  in pppol2tp_sock_to_session()
151 	if (session && refcount_inc_not_zero(&session->ref_count)) {  in pppol2tp_sock_to_session()
153 		WARN_ON_ONCE(session->magic != L2TP_SESSION_MAGIC);  in pppol2tp_sock_to_session()
154 		return session;  in pppol2tp_sock_to_session()
197 static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)  in pppol2tp_recv()  argument
202 	 * queue it on the session socket.  in pppol2tp_recv()
205 	sk = pppol2tp_session_get_sock(session);  in pppol2tp_recv()
227 			atomic_long_inc(&session->stats.rx_errors);  in pppol2tp_recv()
237 	pr_warn_ratelimited("%s: no socket in recv\n", session->name);  in pppol2tp_recv()
246  * when a user application does a sendmsg() on the session socket. L2TP and
255 	struct l2tp_session *session;  in pppol2tp_sendmsg()  local
263 	/* Get session and tunnel contexts */  in pppol2tp_sendmsg()
265 	session = pppol2tp_sock_to_session(sk);  in pppol2tp_sendmsg()
266 	if (!session)  in pppol2tp_sendmsg()
269 	tunnel = session->tunnel;  in pppol2tp_sendmsg()
276 			   uhlen + session->hdr_len +  in pppol2tp_sendmsg()
302 	l2tp_xmit_skb(session, skb);  in pppol2tp_sendmsg()
305 	l2tp_session_put(session);  in pppol2tp_sendmsg()
310 	l2tp_session_put(session);  in pppol2tp_sendmsg()
332 	struct l2tp_session *session;  in pppol2tp_xmit()  local
339 	/* Get session and tunnel contexts from the socket */  in pppol2tp_xmit()
340 	session = pppol2tp_sock_to_session(sk);  in pppol2tp_xmit()
341 	if (!session)  in pppol2tp_xmit()
344 	tunnel = session->tunnel;  in pppol2tp_xmit()
350 		   session->hdr_len +	/* L2TP header */  in pppol2tp_xmit()
361 	l2tp_xmit_skb(session, skb);  in pppol2tp_xmit()
364 	l2tp_session_put(session);  in pppol2tp_xmit()
369 	l2tp_session_put(session);  in pppol2tp_xmit()
377  * Session (and tunnel control) socket create/destroy.
380 /* Really kill the session socket. (Called from sock_put() if
389 static void pppol2tp_session_close(struct l2tp_session *session)  in pppol2tp_session_close()  argument
393 	ps = l2tp_session_priv(session);  in pppol2tp_session_close()
405 		l2tp_session_put(session);  in pppol2tp_session_close()
409 /* Called when the PPPoX socket (session) is closed.
414 	struct l2tp_session *session;  in pppol2tp_release()  local
432 	session = pppol2tp_sock_to_session(sk);  in pppol2tp_release()
433 	if (session) {  in pppol2tp_release()
434 		l2tp_session_delete(session);  in pppol2tp_release()
436 		l2tp_session_put(session);  in pppol2tp_release()
499 	struct l2tp_session *session = arg;  in pppol2tp_show()  local
503 	sk = pppol2tp_session_get_sock(session);  in pppol2tp_show()
512 static void pppol2tp_session_init(struct l2tp_session *session)  in pppol2tp_session_init()  argument
516 	session->recv_skb = pppol2tp_recv;  in pppol2tp_session_init()
517 	session->session_close = pppol2tp_session_close;  in pppol2tp_session_init()
519 		session->show = pppol2tp_show;  in pppol2tp_session_init()
521 	ps = l2tp_session_priv(session);  in pppol2tp_session_init()
692 	struct l2tp_session *session = NULL;  in pppol2tp_connect()  local
729 	session = l2tp_session_get(sock_net(sk), tunnel->sock, tunnel->version,  in pppol2tp_connect()
731 	if (session) {  in pppol2tp_connect()
734 		if (session->pwtype != L2TP_PWTYPE_PPP) {  in pppol2tp_connect()
739 		ps = l2tp_session_priv(session);  in pppol2tp_connect()
741 		/* Using a pre-existing session is fine as long as it hasn't  in pppol2tp_connect()
755 		session = l2tp_session_create(sizeof(struct pppol2tp_session),  in pppol2tp_connect()
758 		if (IS_ERR(session)) {  in pppol2tp_connect()
759 			error = PTR_ERR(session);  in pppol2tp_connect()
765 		pppol2tp_session_init(session);  in pppol2tp_connect()
766 		ps = l2tp_session_priv(session);  in pppol2tp_connect()
767 		refcount_inc(&session->ref_count);  in pppol2tp_connect()
770 		error = l2tp_session_register(session, tunnel);  in pppol2tp_connect()
773 			l2tp_session_put(session);  in pppol2tp_connect()
785 	if (session->session_id == 0 && session->peer_session_id == 0) {  in pppol2tp_connect()
809 	/* This is how we get the session context from the socket. */  in pppol2tp_connect()
811 	rcu_assign_sk_user_data(sk, session);  in pppol2tp_connect()
815 	/* Keep the reference we've grabbed on the session: sk doesn't expect  in pppol2tp_connect()
816 	 * the session to disappear. pppol2tp_session_close() is responsible  in pppol2tp_connect()
826 			l2tp_session_delete(session);  in pppol2tp_connect()
831 		l2tp_session_put(session);  in pppol2tp_connect()
846 	struct l2tp_session *session;  in pppol2tp_session_create()  local
854 	/* Allocate and initialize a new session context. */  in pppol2tp_session_create()
855 	session = l2tp_session_create(sizeof(struct pppol2tp_session),  in pppol2tp_session_create()
858 	if (IS_ERR(session)) {  in pppol2tp_session_create()
859 		error = PTR_ERR(session);  in pppol2tp_session_create()
863 	pppol2tp_session_init(session);  in pppol2tp_session_create()
865 	error = l2tp_session_register(session, tunnel);  in pppol2tp_session_create()
872 	l2tp_session_put(session);  in pppol2tp_session_create()
886 	struct l2tp_session *session;  in pppol2tp_getname()  local
899 	session = pppol2tp_sock_to_session(sk);  in pppol2tp_getname()
900 	if (!session)  in pppol2tp_getname()
903 	pls = l2tp_session_priv(session);  in pppol2tp_getname()
904 	tunnel = session->tunnel;  in pppol2tp_getname()
918 		sp.pppol2tp.s_session = session->session_id;  in pppol2tp_getname()
919 		sp.pppol2tp.d_session = session->peer_session_id;  in pppol2tp_getname()
936 		sp.pppol2tp.s_session = session->session_id;  in pppol2tp_getname()
937 		sp.pppol2tp.d_session = session->peer_session_id;  in pppol2tp_getname()
954 		sp.pppol2tp.s_session = session->session_id;  in pppol2tp_getname()
955 		sp.pppol2tp.d_session = session->peer_session_id;  in pppol2tp_getname()
973 		sp.pppol2tp.s_session = session->session_id;  in pppol2tp_getname()
974 		sp.pppol2tp.d_session = session->peer_session_id;  in pppol2tp_getname()
983 	l2tp_session_put(session);  in pppol2tp_getname()
1017 	struct l2tp_session *session;  in pppol2tp_tunnel_copy_stats()  local
1024 	/* If session_id is set, search the corresponding session in the  in pppol2tp_tunnel_copy_stats()
1025 	 * context of this tunnel and record the session's statistics.  in pppol2tp_tunnel_copy_stats()
1027 	session = l2tp_session_get(tunnel->l2tp_net, tunnel->sock, tunnel->version,  in pppol2tp_tunnel_copy_stats()
1029 	if (!session)  in pppol2tp_tunnel_copy_stats()
1032 	if (session->pwtype != L2TP_PWTYPE_PPP) {  in pppol2tp_tunnel_copy_stats()
1033 		l2tp_session_put(session);  in pppol2tp_tunnel_copy_stats()
1037 	pppol2tp_copy_stats(stats, &session->stats);  in pppol2tp_tunnel_copy_stats()
1038 	l2tp_session_put(session);  in pppol2tp_tunnel_copy_stats()
1047 	struct l2tp_session *session;  in pppol2tp_ioctl()  local
1050 	session = pppol2tp_sock_to_session(sock->sk);  in pppol2tp_ioctl()
1052 	/* Validate session presence and magic integrity ONLY for commands  in pppol2tp_ioctl()
1053 	 * that belong to L2TP and require a valid session.  in pppol2tp_ioctl()
1061 		if (!session)  in pppol2tp_ioctl()
1064 		if (session->magic != L2TP_SESSION_MAGIC) {  in pppol2tp_ioctl()
1065 			l2tp_session_put(session);  in pppol2tp_ioctl()
1077 		if (!session->session_id && !session->peer_session_id) {  in pppol2tp_ioctl()
1091 		if (!session->session_id && !session->peer_session_id) {  in pppol2tp_ioctl()
1103 		/* Session 0 represents the parent tunnel */  in pppol2tp_ioctl()
1104 		if (!session->session_id && !session->peer_session_id) {  in pppol2tp_ioctl()
1115 							 session->tunnel);  in pppol2tp_ioctl()
1121 			pppol2tp_copy_stats(&stats, &session->stats);  in pppol2tp_ioctl()
1122 			stats.session_id = session->session_id;  in pppol2tp_ioctl()
1124 		stats.tunnel_id = session->tunnel->tunnel_id;  in pppol2tp_ioctl()
1125 		stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);  in pppol2tp_ioctl()
1138 	if (session)  in pppol2tp_ioctl()
1139 		l2tp_session_put(session);  in pppol2tp_ioctl()
1175 /* Session setsockopt helper.
1178 				       struct l2tp_session *session,  in pppol2tp_session_setsockopt()  argument
1189 		session->recv_seq = !!val;  in pppol2tp_session_setsockopt()
1197 		session->send_seq = !!val;  in pppol2tp_session_setsockopt()
1198 		l2tp_session_set_header_len(session, session->tunnel->version,  in pppol2tp_session_setsockopt()
1199 					    session->tunnel->encap);  in pppol2tp_session_setsockopt()
1207 		session->lns_mode = !!val;  in pppol2tp_session_setsockopt()
1211 		/* Session debug flags option is deprecated */  in pppol2tp_session_setsockopt()
1215 		session->reorder_timeout = msecs_to_jiffies(val);  in pppol2tp_session_setsockopt()
1227  * Does API checks, then calls either the tunnel or session setsockopt
1229  * session or the special tunnel type.
1235 	struct l2tp_session *session;  in pppol2tp_setsockopt()  local
1253 	/* Get session context from the socket */  in pppol2tp_setsockopt()
1255 	session = pppol2tp_sock_to_session(sk);  in pppol2tp_setsockopt()
1256 	if (!session)  in pppol2tp_setsockopt()
1261 	if (session->session_id == 0 && session->peer_session_id == 0) {  in pppol2tp_setsockopt()
1262 		tunnel = session->tunnel;  in pppol2tp_setsockopt()
1265 		err = pppol2tp_session_setsockopt(sk, session, optname, val);  in pppol2tp_setsockopt()
1268 	l2tp_session_put(session);  in pppol2tp_setsockopt()
1295 /* Session getsockopt helper. Called with sock locked.
1298 				       struct l2tp_session *session,  in pppol2tp_session_getsockopt()  argument
1305 		*val = session->recv_seq;  in pppol2tp_session_getsockopt()
1309 		*val = session->send_seq;  in pppol2tp_session_getsockopt()
1313 		*val = session->lns_mode;  in pppol2tp_session_getsockopt()
1317 		/* Session debug flags option is deprecated */  in pppol2tp_session_getsockopt()
1322 		*val = (int)jiffies_to_msecs(session->reorder_timeout);  in pppol2tp_session_getsockopt()
1333  * Does API checks, then calls either the tunnel or session getsockopt
1334  * handler, according to whether the PPPoX socket is a for a regular session
1341 	struct l2tp_session *session;  in pppol2tp_getsockopt()  local
1361 	/* Get the session context */  in pppol2tp_getsockopt()
1363 	session = pppol2tp_sock_to_session(sk);  in pppol2tp_getsockopt()
1364 	if (!session)  in pppol2tp_getsockopt()
1368 	if (session->session_id == 0 && session->peer_session_id == 0) {  in pppol2tp_getsockopt()
1369 		tunnel = session->tunnel;  in pppol2tp_getsockopt()
1374 		err = pppol2tp_session_getsockopt(sk, session, optname, &val);  in pppol2tp_getsockopt()
1389 	l2tp_session_put(session);  in pppol2tp_getsockopt()
1405 	unsigned long skey;		/* lookup key of current session */
1407 	struct l2tp_session *session;	/* NULL means get next tunnel */  member
1431 	if (pd->session)  in pppol2tp_next_session()
1432 		l2tp_session_put(pd->session);  in pppol2tp_next_session()
1434 	pd->session = l2tp_session_get_next(net, pd->tunnel->sock,  in pppol2tp_next_session()
1439 	if (!pd->session) {  in pppol2tp_next_session()
1467 	/* NULL tunnel and session indicates end of list */  in pppol2tp_seq_start()
1468 	if (!pd->tunnel && !pd->session)  in pppol2tp_seq_start()
1491 	if (pd->session) {  in pppol2tp_seq_stop()
1492 		l2tp_session_put(pd->session);  in pppol2tp_seq_stop()
1493 		pd->session = NULL;  in pppol2tp_seq_stop()
1521 	struct l2tp_session *session = v;  in pppol2tp_seq_session_show()  local
1522 	struct l2tp_tunnel *tunnel = session->tunnel;  in pppol2tp_seq_session_show()
1537 	sk = pppol2tp_session_get_sock(session);  in pppol2tp_seq_session_show()
1540 		user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';  in pppol2tp_seq_session_show()
1546 	seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> %04X/%04X %d %c\n",  in pppol2tp_seq_session_show()
1547 		   session->name, ip, port,  in pppol2tp_seq_session_show()
1549 		   session->session_id,  in pppol2tp_seq_session_show()
1551 		   session->peer_session_id,  in pppol2tp_seq_session_show()
1554 		   session->recv_seq ? 'R' : '-',  in pppol2tp_seq_session_show()
1555 		   session->send_seq ? 'S' : '-',  in pppol2tp_seq_session_show()
1556 		   session->lns_mode ? "LNS" : "LAC",  in pppol2tp_seq_session_show()
1558 		   jiffies_to_msecs(session->reorder_timeout));  in pppol2tp_seq_session_show()
1560 		   session->nr, session->ns,  in pppol2tp_seq_session_show()
1561 		   atomic_long_read(&session->stats.tx_packets),  in pppol2tp_seq_session_show()
1562 		   atomic_long_read(&session->stats.tx_bytes),  in pppol2tp_seq_session_show()
1563 		   atomic_long_read(&session->stats.tx_errors),  in pppol2tp_seq_session_show()
1564 		   atomic_long_read(&session->stats.rx_packets),  in pppol2tp_seq_session_show()
1565 		   atomic_long_read(&session->stats.rx_bytes),  in pppol2tp_seq_session_show()
1566 		   atomic_long_read(&session->stats.rx_errors));  in pppol2tp_seq_session_show()
1583 		seq_puts(m, "TUNNEL name, user-data-ok session-count\n");  in pppol2tp_seq_show()
1585 		seq_puts(m, "  SESSION name, addr/port src-tid/sid dest-tid/sid state user-data-ok\n");  in pppol2tp_seq_show()
1591 	if (!pd->session)  in pppol2tp_seq_show()
1594 		pppol2tp_seq_session_show(m, pd->session);  in pppol2tp_seq_show()