l2tp: remove tunnel and session debug flags field

The l2tp subsystem now uses standard kernel logging APIs for
informational and warning messages, and tracepoints for debug
information.

Now that the tunnel and session debug flags are unused, remove the field
from the core structures.

Various system calls (in the case of l2tp_ppp) and netlink messages
handle the getting and setting of debug flags.  To avoid userspace
breakage don't modify the API of these calls; simply ignore set
requests, and send dummy data for get requests.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_pppol2tp.h

@@ -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

@@ -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/l2tp_core.c

@@ -1401,16 +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);
@@ -1608,12 +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;

net/l2tp/l2tp_core.h

@@ -51,7 +51,6 @@ struct l2tp_session_cfg {
 	unsigned int		lns_mode:1;	/* behave as LNS?
 						 * LAC enables sequence numbers under LNS control.
 						 */
-	int			debug;		/* bitmask of debug message categories */
 	u16			l2specific_type; /* Layer 2 specific type */
 	u8			cookie[8];	/* optional cookie */
 	int			cookie_len;	/* 0, 4 or 8 bytes */
@@ -98,7 +97,6 @@ struct l2tp_session {
 	unsigned int		lns_mode:1;	/* behave as LNS?
 						 * LAC enables sequence numbers under LNS control.
 						 */
-	int			debug;		/* bitmask of debug message categories */
 	int			reorder_timeout; /* configured reorder timeout (in jiffies) */
 	int			reorder_skip;	/* set if skip to next nr */
 	enum l2tp_pwtype	pwtype;
@@ -132,7 +130,6 @@ struct l2tp_session {
 
 /* L2TP tunnel configuration */
 struct l2tp_tunnel_cfg {
-	int			debug;		/* bitmask of debug message categories */
 	enum l2tp_encap_type	encap;
 
 	/* Used only for kernel-created sockets */
@@ -173,7 +170,6 @@ struct l2tp_tunnel {
 	int			version;	/* 2=>L2TPv2, 3=>L2TPv3 */
 
 	char			name[L2TP_TUNNEL_NAME_MAX]; /* for logging */
-	int			debug;		/* bitmask of debug message categories */
 	enum l2tp_encap_type	encap;
 	struct l2tp_stats	stats;
 

net/l2tp/l2tp_debugfs.c

@@ -167,7 +167,7 @@ static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 		   tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
 		   refcount_read(&tunnel->ref_count));
 	seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
-		   tunnel->debug,
+		   0,
 		   atomic_long_read(&tunnel->stats.tx_packets),
 		   atomic_long_read(&tunnel->stats.tx_bytes),
 		   atomic_long_read(&tunnel->stats.tx_errors),
@@ -192,7 +192,7 @@ static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
 		   session->recv_seq ? 'R' : '-',
 		   session->send_seq ? 'S' : '-',
 		   session->lns_mode ? "LNS" : "LAC",
-		   session->debug,
+		   0,
 		   jiffies_to_msecs(session->reorder_timeout));
 	seq_printf(m, "   offset 0 l2specific %hu/%hu\n",
 		   session->l2specific_type, l2tp_get_l2specific_len(session));

net/l2tp/l2tp_netlink.c

@@ -229,9 +229,6 @@ static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info
 			goto out;
 	}
 
-	if (attrs[L2TP_ATTR_DEBUG])
-		cfg.debug = nla_get_u32(attrs[L2TP_ATTR_DEBUG]);
-
 	ret = -EINVAL;
 	switch (cfg.encap) {
 	case L2TP_ENCAPTYPE_UDP:
@@ -307,9 +304,6 @@ static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info
 		goto out;
 	}
 
-	if (info->attrs[L2TP_ATTR_DEBUG])
-		tunnel->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
-
 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
 				 tunnel, L2TP_CMD_TUNNEL_MODIFY);
 
@@ -400,7 +394,7 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int fla
 	if (nla_put_u8(skb, L2TP_ATTR_PROTO_VERSION, tunnel->version) ||
 	    nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
-	    nla_put_u32(skb, L2TP_ATTR_DEBUG, tunnel->debug) ||
+	    nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
 	    nla_put_u16(skb, L2TP_ATTR_ENCAP_TYPE, tunnel->encap))
 		goto nla_put_failure;
 
@@ -605,9 +599,6 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
 			cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
 	}
 
-	if (info->attrs[L2TP_ATTR_DEBUG])
-		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
-
 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
 		cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
 
@@ -689,9 +680,6 @@ static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *inf
 		goto out;
 	}
 
-	if (info->attrs[L2TP_ATTR_DEBUG])
-		session->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
-
 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
 		session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
 
@@ -730,7 +718,7 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int fl
 	    nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
 	    nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID, session->peer_session_id) ||
-	    nla_put_u32(skb, L2TP_ATTR_DEBUG, session->debug) ||
+	    nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
 	    nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
 		goto nla_put_failure;
 

net/l2tp/l2tp_ppp.c

@@ -702,7 +702,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 		if (!tunnel) {
 			struct l2tp_tunnel_cfg tcfg = {
 				.encap = L2TP_ENCAPTYPE_UDP,
-				.debug = 0,
 			};
 
 			/* Prevent l2tp_tunnel_register() from trying to set up
@@ -1147,7 +1146,7 @@ static int pppol2tp_tunnel_setsockopt(struct sock *sk,
 
 	switch (optname) {
 	case PPPOL2TP_SO_DEBUG:
-		tunnel->debug = val;
+		/* Tunnel debug flags option is deprecated */
 		break;
 
 	default:
@@ -1199,7 +1198,7 @@ static int pppol2tp_session_setsockopt(struct sock *sk,
 		break;
 
 	case PPPOL2TP_SO_DEBUG:
-		session->debug = val;
+		/* Session debug flags option is deprecated */
 		break;
 
 	case PPPOL2TP_SO_REORDERTO:
@@ -1271,7 +1270,8 @@ static int pppol2tp_tunnel_getsockopt(struct sock *sk,
 
 	switch (optname) {
 	case PPPOL2TP_SO_DEBUG:
-		*val = tunnel->debug;
+		/* Tunnel debug flags option is deprecated */
+		*val = 0;
 		break;
 
 	default:
@@ -1304,7 +1304,8 @@ static int pppol2tp_session_getsockopt(struct sock *sk,
 		break;
 
 	case PPPOL2TP_SO_DEBUG:
-		*val = session->debug;
+		/* Session debug flags option is deprecated */
+		*val = 0;
 		break;
 
 	case PPPOL2TP_SO_REORDERTO:
@@ -1496,7 +1497,7 @@ static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
 		   (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
 		   refcount_read(&tunnel->ref_count) - 1);
 	seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
-		   tunnel->debug,
+		   0,
 		   atomic_long_read(&tunnel->stats.tx_packets),
 		   atomic_long_read(&tunnel->stats.tx_bytes),
 		   atomic_long_read(&tunnel->stats.tx_errors),
@@ -1542,7 +1543,7 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
 		   session->recv_seq ? 'R' : '-',
 		   session->send_seq ? 'S' : '-',
 		   session->lns_mode ? "LNS" : "LAC",
-		   session->debug,
+		   0,
 		   jiffies_to_msecs(session->reorder_timeout));
 	seq_printf(m, "   %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
 		   session->nr, session->ns,