Merge branch 'l2tp-replace-custom-logging-code-with-tracepoints' (d7223aa5) · Commits · 戴 / test

Documentation/networking/l2tp.rst

+14 −23

Original line number	Diff line number	Diff line
		@@ -455,31 +455,16 @@ l2tp help`` for more information.
		Debugging
		---------

		The L2TP subsystem offers a debug scheme where kernel trace messages
		may be optionally enabled per tunnel and per session. Care is needed
		when debugging a live system since the messages are not rate-limited
		and a busy system could be swamped. Userspace uses setsockopt on the
		PPPoX socket to set a debug mask, or ``L2TP_ATTR_DEBUG`` in netlink
		Create and Modify commands.
		The L2TP subsystem offers a range of debugging interfaces through the
		debugfs filesystem.

		The following debug mask bits are defined:-

		================ ==============================
		L2TP_MSG_DEBUG verbose debug (if compiled in)
		L2TP_MSG_CONTROL userspace - kernel interface
		L2TP_MSG_SEQ sequence numbers handling
		L2TP_MSG_DATA data packets
		================ ==============================

		Sessions inherit default debug flags from the parent tunnel.

		If enabled, files under a l2tp debugfs directory can be used to dump
		kernel state about L2TP tunnels and sessions. To access it, the
		debugfs filesystem must first be mounted::
		To access these interfaces, the debugfs filesystem must first be mounted::

		# mount -t debugfs debugfs /debug

		Files under the l2tp directory can then be accessed::
		Files under the l2tp directory can then be accessed, providing a summary
		of the current population of tunnel and session contexts existing in the
		kernel::

		# cat /debug/l2tp/tunnels

		@@ -488,8 +473,14 @@ state information because the file format is subject to change. It is
		implemented to provide extra debug information to help diagnose
		problems. Applications should instead use the netlink API.

		/proc/net/pppol2tp is also provided for backwards compatibility with
		the original pppol2tp code. It lists information about L2TPv2
		In addition the L2TP subsystem implements tracepoints using the standard
		kernel event tracing API. The available L2TP events can be reviewed as
		follows::

		# find /debug/tracing/events/l2tp

		Finally, /proc/net/pppol2tp is also provided for backwards compatibility
		with the original pppol2tp code. It lists information about L2TPv2
		tunnels and sessions only. Its use is discouraged.

		Internal Implementation

include/uapi/linux/if_pppol2tp.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -75,7 +75,7 @@ struct pppol2tpv3in6_addr {
		};

		/* Socket options:
		* DEBUG - bitmask of debug message categories
		* DEBUG - bitmask of debug message categories (not used)
		* SENDSEQ - 0 => don't send packets with sequence numbers
		* 1 => send packets with sequence numbers
		* RECVSEQ - 0 => receive packet sequence numbers are optional

include/uapi/linux/l2tp.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -108,7 +108,7 @@ enum {
		L2TP_ATTR_VLAN_ID, /* u16 (not used) */
		L2TP_ATTR_COOKIE, /* 0, 4 or 8 bytes */
		L2TP_ATTR_PEER_COOKIE, /* 0, 4 or 8 bytes */
		L2TP_ATTR_DEBUG, /* u32, enum l2tp_debug_flags */
		L2TP_ATTR_DEBUG, /* u32, enum l2tp_debug_flags (not used) */
		L2TP_ATTR_RECV_SEQ, /* u8 */
		L2TP_ATTR_SEND_SEQ, /* u8 */
		L2TP_ATTR_LNS_MODE, /* u8 */
		@@ -177,7 +177,9 @@ enum l2tp_seqmode {
		};

		/**
		* enum l2tp_debug_flags - debug message categories for L2TP tunnels/sessions
		* enum l2tp_debug_flags - debug message categories for L2TP tunnels/sessions.
		*
		* Unused.
		*
		* @L2TP_MSG_DEBUG: verbose debug (if compiled in)
		* @L2TP_MSG_CONTROL: userspace - kernel interface

net/l2tp/Makefile

+2 −0

Original line number	Diff line number	Diff line
		@@ -5,6 +5,8 @@

		obj-$(CONFIG_L2TP) += l2tp_core.o

		CFLAGS_l2tp_core.o += -I$(src)

		# Build l2tp as modules if L2TP is M
		obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_PPPOL2TP)) += l2tp_ppp.o
		obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip.o

net/l2tp/l2tp_core.c

+53 −139

Original line number	Diff line number	Diff line
		@@ -61,6 +61,10 @@
		#include <linux/atomic.h>

		#include "l2tp_core.h"
		#include "trace.h"

		#define CREATE_TRACE_POINTS
		#include "trace.h"

		#define L2TP_DRV_VERSION "V2.0"

		@@ -151,6 +155,7 @@ l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)

		static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
		{
		trace_free_tunnel(tunnel);
		sock_put(tunnel->sock);
		/* the tunnel is freed in the socket destructor */
		}
		@@ -159,6 +164,8 @@ static void l2tp_session_free(struct l2tp_session *session)
		{
		struct l2tp_tunnel *tunnel = session->tunnel;

		trace_free_session(session);

		if (tunnel) {
		if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))
		goto out;
		@@ -381,6 +388,8 @@ int l2tp_session_register(struct l2tp_session *session,
		hlist_add_head(&session->hlist, head);
		write_unlock_bh(&tunnel->hlist_lock);

		trace_register_session(session);

		return 0;

		err_tlock_pnlock:
		@@ -409,10 +418,6 @@ static void l2tp_recv_queue_skb(struct l2tp_session session, struct sk_buff sk
		skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
		if (L2TP_SKB_CB(skbp)->ns > ns) {
		__skb_queue_before(&session->reorder_q, skbp, skb);
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
		session->name, ns, L2TP_SKB_CB(skbp)->ns,
		skb_queue_len(&session->reorder_q));
		atomic_long_inc(&session->stats.rx_oos_packets);
		goto out;
		}
		@@ -445,9 +450,7 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session session, struct sk_buff
		/* Bump our Nr */
		session->nr++;
		session->nr &= session->nr_max;

		l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
		session->name, session->nr);
		trace_session_seqnum_update(session);
		}

		/* call private receive handler */
		@@ -472,37 +475,27 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
		start:
		spin_lock_bh(&session->reorder_q.lock);
		skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
		if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
		struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb);

		/* If the packet has been pending on the queue for too long, discard it */
		if (time_after(jiffies, cb->expires)) {
		atomic_long_inc(&session->stats.rx_seq_discards);
		atomic_long_inc(&session->stats.rx_errors);
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
		session->name, L2TP_SKB_CB(skb)->ns,
		L2TP_SKB_CB(skb)->length, session->nr,
		skb_queue_len(&session->reorder_q));
		trace_session_pkt_expired(session, cb->ns);
		session->reorder_skip = 1;
		__skb_unlink(skb, &session->reorder_q);
		kfree_skb(skb);
		continue;
		}

		if (L2TP_SKB_CB(skb)->has_seq) {
		if (cb->has_seq) {
		if (session->reorder_skip) {
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: advancing nr to next pkt: %u -> %u",
		session->name, session->nr,
		L2TP_SKB_CB(skb)->ns);
		session->reorder_skip = 0;
		session->nr = L2TP_SKB_CB(skb)->ns;
		}
		if (L2TP_SKB_CB(skb)->ns != session->nr) {
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
		session->name, L2TP_SKB_CB(skb)->ns,
		L2TP_SKB_CB(skb)->length, session->nr,
		skb_queue_len(&session->reorder_q));
		goto out;
		session->nr = cb->ns;
		trace_session_seqnum_reset(session);
		}
		if (cb->ns != session->nr)
		goto out;
		}
		__skb_unlink(skb, &session->reorder_q);

		@@ -535,14 +528,13 @@ static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
		*/
		static int l2tp_recv_data_seq(struct l2tp_session session, struct sk_buff skb)
		{
		if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
		struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb);

		if (!l2tp_seq_check_rx_window(session, cb->ns)) {
		/* Packet sequence number is outside allowed window.
		* Discard it.
		*/
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: pkt %u len %d discarded, outside window, nr=%u\n",
		session->name, L2TP_SKB_CB(skb)->ns,
		L2TP_SKB_CB(skb)->length, session->nr);
		trace_session_pkt_outside_rx_window(session, cb->ns);
		goto discard;
		}

		@@ -559,10 +551,10 @@ static int l2tp_recv_data_seq(struct l2tp_session session, struct sk_buff skb)
		* is seen. After nr_oos_count_max in-sequence packets, reset the
		* sequence number to re-enable packet reception.
		*/
		if (L2TP_SKB_CB(skb)->ns == session->nr) {
		if (cb->ns == session->nr) {
		skb_queue_tail(&session->reorder_q, skb);
		} else {
		u32 nr_oos = L2TP_SKB_CB(skb)->ns;
		u32 nr_oos = cb->ns;
		u32 nr_next = (session->nr_oos + 1) & session->nr_max;

		if (nr_oos == nr_next)
		@@ -573,17 +565,10 @@ static int l2tp_recv_data_seq(struct l2tp_session session, struct sk_buff skb)
		session->nr_oos = nr_oos;
		if (session->nr_oos_count > session->nr_oos_count_max) {
		session->reorder_skip = 1;
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: %d oos packets received. Resetting sequence numbers\n",
		session->name, session->nr_oos_count);
		}
		if (!session->reorder_skip) {
		atomic_long_inc(&session->stats.rx_seq_discards);
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
		session->name, L2TP_SKB_CB(skb)->ns,
		L2TP_SKB_CB(skb)->length, session->nr,
		skb_queue_len(&session->reorder_q));
		trace_session_pkt_oos(session, cb->ns);
		goto discard;
		}
		skb_queue_tail(&session->reorder_q, skb);
		@@ -660,14 +645,12 @@ void l2tp_recv_common(struct l2tp_session session, struct sk_buff skb,
		int length)
		{
		struct l2tp_tunnel *tunnel = session->tunnel;
		u32 ns = 0, nr = 0;
		int offset;

		/* Parse and check optional cookie */
		if (session->peer_cookie_len > 0) {
		if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
		l2tp_info(tunnel, L2TP_MSG_DATA,
		"%s: cookie mismatch (%u/%u). Discarding.\n",
		pr_warn_ratelimited("%s: cookie mismatch (%u/%u). Discarding.\n",
		tunnel->name, tunnel->tunnel_id,
		session->session_id);
		atomic_long_inc(&session->stats.rx_cookie_discards);
		@@ -686,32 +669,21 @@ void l2tp_recv_common(struct l2tp_session session, struct sk_buff skb,
		L2TP_SKB_CB(skb)->has_seq = 0;
		if (tunnel->version == L2TP_HDR_VER_2) {
		if (hdrflags & L2TP_HDRFLAG_S) {
		ns = ntohs((__be16 )ptr);
		ptr += 2;
		nr = ntohs((__be16 )ptr);
		ptr += 2;

		/* Store L2TP info in the skb */
		L2TP_SKB_CB(skb)->ns = ns;
		L2TP_SKB_CB(skb)->ns = ntohs((__be16 )ptr);
		L2TP_SKB_CB(skb)->has_seq = 1;
		ptr += 2;
		/* Skip past nr in the header */
		ptr += 2;

		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: recv data ns=%u, nr=%u, session nr=%u\n",
		session->name, ns, nr, session->nr);
		}
		} else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
		u32 l2h = ntohl((__be32 )ptr);

		if (l2h & 0x40000000) {
		ns = l2h & 0x00ffffff;

		/* Store L2TP info in the skb */
		L2TP_SKB_CB(skb)->ns = ns;
		L2TP_SKB_CB(skb)->ns = l2h & 0x00ffffff;
		L2TP_SKB_CB(skb)->has_seq = 1;

		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: recv data ns=%u, session nr=%u\n",
		session->name, ns, session->nr);
		}
		ptr += 4;
		}
		@@ -722,9 +694,7 @@ void l2tp_recv_common(struct l2tp_session session, struct sk_buff skb,
		* configure it so.
		*/
		if (!session->lns_mode && !session->send_seq) {
		l2tp_info(session, L2TP_MSG_SEQ,
		"%s: requested to enable seq numbers by LNS\n",
		session->name);
		trace_session_seqnum_lns_enable(session);
		session->send_seq = 1;
		l2tp_session_set_header_len(session, tunnel->version);
		}
		@@ -733,8 +703,7 @@ void l2tp_recv_common(struct l2tp_session session, struct sk_buff skb,
		* If user has configured mandatory sequence numbers, discard.
		*/
		if (session->recv_seq) {
		l2tp_warn(session, L2TP_MSG_SEQ,
		"%s: recv data has no seq numbers when required. Discarding.\n",
		pr_warn_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n",
		session->name);
		atomic_long_inc(&session->stats.rx_seq_discards);
		goto discard;
		@@ -746,14 +715,11 @@ void l2tp_recv_common(struct l2tp_session session, struct sk_buff skb,
		* LAC is broken. Discard the frame.
		*/
		if (!session->lns_mode && session->send_seq) {
		l2tp_info(session, L2TP_MSG_SEQ,
		"%s: requested to disable seq numbers by LNS\n",
		session->name);
		trace_session_seqnum_lns_disable(session);
		session->send_seq = 0;
		l2tp_session_set_header_len(session, tunnel->version);
		} else if (session->send_seq) {
		l2tp_warn(session, L2TP_MSG_SEQ,
		"%s: recv data has no seq numbers when required. Discarding.\n",
		pr_warn_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n",
		session->name);
		atomic_long_inc(&session->stats.rx_seq_discards);
		goto discard;
		@@ -847,22 +813,11 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel tunnel, struct sk_buff skb)

		/* Short packet? */
		if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) {
		l2tp_info(tunnel, L2TP_MSG_DATA,
		"%s: recv short packet (len=%d)\n",
		pr_warn_ratelimited("%s: recv short packet (len=%d)\n",
		tunnel->name, skb->len);
		goto error;
		}

		/* Trace packet contents, if enabled */
		if (tunnel->debug & L2TP_MSG_DATA) {
		length = min(32u, skb->len);
		if (!pskb_may_pull(skb, length))
		goto error;

		pr_debug("%s: recv\n", tunnel->name);
		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
		}

		/* Point to L2TP header */
		optr = skb->data;
		ptr = skb->data;
		@@ -873,8 +828,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel tunnel, struct sk_buff skb)
		/* Check protocol version */
		version = hdrflags & L2TP_HDR_VER_MASK;
		if (version != tunnel->version) {
		l2tp_info(tunnel, L2TP_MSG_DATA,
		"%s: recv protocol version mismatch: got %d expected %d\n",
		pr_warn_ratelimited("%s: recv protocol version mismatch: got %d expected %d\n",
		tunnel->name, version, tunnel->version);
		goto error;
		}
		@@ -883,12 +837,8 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel tunnel, struct sk_buff skb)
		length = skb->len;

		/* If type is control packet, it is handled by userspace. */
		if (hdrflags & L2TP_HDRFLAG_T) {
		l2tp_dbg(tunnel, L2TP_MSG_DATA,
		"%s: recv control packet, len=%d\n",
		tunnel->name, length);
		if (hdrflags & L2TP_HDRFLAG_T)
		goto error;
		}

		/* Skip flags */
		ptr += 2;
		@@ -917,8 +867,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel tunnel, struct sk_buff skb)
		l2tp_session_dec_refcount(session);

		/* Not found? Pass to userspace to deal with */
		l2tp_info(tunnel, L2TP_MSG_DATA,
		"%s: no session found (%u/%u). Passing up.\n",
		pr_warn_ratelimited("%s: no session found (%u/%u). Passing up.\n",
		tunnel->name, tunnel_id, session_id);
		goto error;
		}
		@@ -953,9 +902,6 @@ int l2tp_udp_encap_recv(struct sock sk, struct sk_buff skb)
		if (!tunnel)
		goto pass_up;

		l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
		tunnel->name, skb->len);

		if (l2tp_udp_recv_core(tunnel, skb))
		goto pass_up;

		@@ -993,8 +939,7 @@ static int l2tp_build_l2tpv2_header(struct l2tp_session session, void buf)
		*bufp++ = 0;
		session->ns++;
		session->ns &= 0xffff;
		l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
		session->name, session->ns);
		trace_session_seqnum_update(session);
		}

		return bufp - optr;
		@@ -1030,9 +975,7 @@ static int l2tp_build_l2tpv3_header(struct l2tp_session session, void buf)
		l2h = 0x40000000 \| session->ns;
		session->ns++;
		session->ns &= 0xffffff;
		l2tp_dbg(session, L2TP_MSG_SEQ,
		"%s: updated ns to %u\n",
		session->name, session->ns);
		trace_session_seqnum_update(session);
		}

		((__be32 )bufp) = htonl(l2h);
		@@ -1049,23 +992,6 @@ static void l2tp_xmit_core(struct l2tp_session session, struct sk_buff skb,
		unsigned int len = skb->len;
		int error;

		/* Debug */
		if (session->send_seq)
		l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes, ns=%u\n",
		session->name, data_len, session->ns - 1);
		else
		l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes\n",
		session->name, data_len);

		if (session->debug & L2TP_MSG_DATA) {
		int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
		unsigned char *datap = skb->data + uhlen;

		pr_debug("%s: xmit\n", session->name);
		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
		datap, min_t(size_t, 32, len - uhlen));
		}

		/* Queue the packet to IP for output */
		skb->ignore_df = 1;
		skb_dst_drop(skb);
		@@ -1195,8 +1121,6 @@ static void l2tp_tunnel_destruct(struct sock *sk)
		if (!tunnel)
		goto end;

		l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);

		/* Disable udp encapsulation */
		switch (tunnel->encap) {
		case L2TP_ENCAPTYPE_UDP:
		@@ -1255,9 +1179,6 @@ static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
		struct hlist_node *tmp;
		struct l2tp_session *session;

		l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
		tunnel->name);

		write_lock_bh(&tunnel->hlist_lock);
		tunnel->acpt_newsess = false;
		for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
		@@ -1265,9 +1186,6 @@ again:
		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
		session = hlist_entry(walk, struct l2tp_session, hlist);

		l2tp_info(session, L2TP_MSG_CONTROL,
		"%s: closing session\n", session->name);

		hlist_del_init(&session->hlist);

		if (test_and_set_bit(0, &session->dead))
		@@ -1483,16 +1401,12 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
		tunnel->version = version;
		tunnel->tunnel_id = tunnel_id;
		tunnel->peer_tunnel_id = peer_tunnel_id;
		tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;

		tunnel->magic = L2TP_TUNNEL_MAGIC;
		sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
		rwlock_init(&tunnel->hlist_lock);
		tunnel->acpt_newsess = true;

		if (cfg)
		tunnel->debug = cfg->debug;

		tunnel->encap = encap;

		refcount_set(&tunnel->ref_count, 1);
		@@ -1597,6 +1511,8 @@ int l2tp_tunnel_register(struct l2tp_tunnel tunnel, struct net net,
		"l2tp_sock");
		sk->sk_allocation = GFP_ATOMIC;

		trace_register_tunnel(tunnel);

		if (tunnel->fd >= 0)
		sockfd_put(sock);

		@@ -1617,6 +1533,7 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_register);
		void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
		{
		if (!test_and_set_bit(0, &tunnel->dead)) {
		trace_delete_tunnel(tunnel);
		l2tp_tunnel_inc_refcount(tunnel);
		queue_work(l2tp_wq, &tunnel->del_work);
		}
		@@ -1628,6 +1545,7 @@ void l2tp_session_delete(struct l2tp_session *session)
		if (test_and_set_bit(0, &session->dead))
		return;

		trace_delete_session(session);
		l2tp_session_unhash(session);
		l2tp_session_queue_purge(session);
		if (session->session_close)
		@@ -1686,12 +1604,8 @@ struct l2tp_session l2tp_session_create(int priv_size, struct l2tp_tunnel tunn
		INIT_HLIST_NODE(&session->hlist);
		INIT_HLIST_NODE(&session->global_hlist);

		/* Inherit debug options from tunnel */
		session->debug = tunnel->debug;

		if (cfg) {
		session->pwtype = cfg->pw_type;
		session->debug = cfg->debug;
		session->send_seq = cfg->send_seq;
		session->recv_seq = cfg->recv_seq;
		session->lns_mode = cfg->lns_mode;

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