net: sctp: rework debugging framework to use pr_debug and friends

We should get rid of all own SCTP debug printk macros and use the ones
that the kernel offers anyway instead. This makes the code more readable
and conform to the kernel code, and offers all the features of dynamic
debbuging that pr_debug() et al has, such as only turning on/off portions
of debug messages at runtime through debugfs. The runtime cost of having
CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing,
is negligible [1]. If kernel debugging is completly turned off, then these
statements will also compile into "empty" functions.

While we're at it, we also need to change the Kconfig option as it /now/
only refers to the ifdef'ed code portions in outqueue.c that enable further
debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code
was enabled with this Kconfig option and has now been removed, we
transform those code parts into WARNs resp. where appropriate BUG_ONs so
that those bugs can be more easily detected as probably not many people
have SCTP debugging permanently turned on.

To turn on all SCTP debugging, the following steps are needed:

 # mount -t debugfs none /sys/kernel/debug
 # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control

This can be done more fine-grained on a per file, per line basis and others
as described in [2].

 [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf
 [2] Documentation/dynamic-debug-howto.txt

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 47 insertions, 30 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b3d186856513..f6b7109195a6 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1179,9 +1179,9 @@ sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
 	/* Check if the timestamp looks valid.  */
 	if (time_after(hbinfo->sent_at, jiffies) ||
 	    time_after(jiffies, hbinfo->sent_at + max_interval)) {
-		SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
-				  "received for transport: %p\n",
-				   __func__, link);
+		pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
+			 "for transport:%p\n", __func__, link);
+
 		return SCTP_DISPOSITION_DISCARD;
 	}
 
@@ -2562,7 +2562,8 @@ static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
 					   const struct sctp_association *asoc,
 					   struct sctp_transport *transport)
 {
-	SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
+	pr_debug("%s: ABORT received (INIT)\n", __func__);
+
 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 			SCTP_STATE(SCTP_STATE_CLOSED));
 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
@@ -2572,6 +2573,7 @@ static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
 	/* CMD_INIT_FAILED will DELETE_TCB. */
 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
 			SCTP_PERR(error));
+
 	return SCTP_DISPOSITION_ABORT;
 }
 
@@ -2637,8 +2639,9 @@ sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
 	ctsn = ntohl(sdh->cum_tsn_ack);
 
 	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
-		SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
-		SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
+		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
+			 asoc->ctsn_ack_point);
+
 		return SCTP_DISPOSITION_DISCARD;
 	}
 
@@ -2721,8 +2724,9 @@ sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
 	ctsn = ntohl(sdh->cum_tsn_ack);
 
 	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
-		SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
-		SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
+		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
+			 asoc->ctsn_ack_point);
+
 		return SCTP_DISPOSITION_DISCARD;
 	}
 
@@ -3174,8 +3178,9 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net,
 	 *     Point indicates an out-of-order SACK.
 	 */
 	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
-		SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
-		SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
+		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
+			 asoc->ctsn_ack_point);
+
 		return SCTP_DISPOSITION_DISCARD;
 	}
 
@@ -3859,7 +3864,7 @@ sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net,
 	skb_pull(chunk->skb, len);
 
 	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
-	SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
+	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
 
 	/* The TSN is too high--silently discard the chunk and count on it
 	 * getting retransmitted later.
@@ -3927,7 +3932,7 @@ sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
 	skb_pull(chunk->skb, len);
 
 	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
-	SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
+	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
 
 	/* The TSN is too high--silently discard the chunk and count on it
 	 * getting retransmitted later.
@@ -4166,7 +4171,7 @@ sctp_disposition_t sctp_sf_unk_chunk(struct net *net,
 	struct sctp_chunk *err_chunk;
 	sctp_chunkhdr_t *hdr;
 
-	SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
+	pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
 
 	if (!sctp_vtag_verify(unk_chunk, asoc))
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
@@ -4256,7 +4261,8 @@ sctp_disposition_t sctp_sf_discard_chunk(struct net *net,
 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
 						  commands);
 
-	SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
+	pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
+
 	return SCTP_DISPOSITION_DISCARD;
 }
 
@@ -5184,7 +5190,9 @@ sctp_disposition_t sctp_sf_ignore_primitive(
 	void *arg,
 	sctp_cmd_seq_t *commands)
 {
-	SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
+	pr_debug("%s: primitive type:%d is ignored\n", __func__,
+		 type.primitive);
+
 	return SCTP_DISPOSITION_DISCARD;
 }
 
@@ -5379,7 +5387,9 @@ sctp_disposition_t sctp_sf_ignore_other(struct net *net,
 					void *arg,
 					sctp_cmd_seq_t *commands)
 {
-	SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
+	pr_debug("%s: the event other type:%d is ignored\n",
+		 __func__, type.other);
+
 	return SCTP_DISPOSITION_DISCARD;
 }
 
@@ -5527,7 +5537,8 @@ sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net,
 	struct sctp_bind_addr *bp;
 	int attempts = asoc->init_err_counter + 1;
 
-	SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
+	pr_debug("%s: timer T1 expired (INIT)\n", __func__);
+
 	SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
 
 	if (attempts <= asoc->max_init_attempts) {
@@ -5546,9 +5557,10 @@ sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net,
 
 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
 	} else {
-		SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
-				  " max_init_attempts: %d\n",
-				  attempts, asoc->max_init_attempts);
+		pr_debug("%s: giving up on INIT, attempts:%d "
+			 "max_init_attempts:%d\n", __func__, attempts,
+			 asoc->max_init_attempts);
+
 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
 				SCTP_ERROR(ETIMEDOUT));
 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
@@ -5588,7 +5600,8 @@ sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net,
 	struct sctp_chunk *repl = NULL;
 	int attempts = asoc->init_err_counter + 1;
 
-	SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
+	pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
+
 	SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
 
 	if (attempts <= asoc->max_init_attempts) {
@@ -5636,7 +5649,8 @@ sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net,
 {
 	struct sctp_chunk *reply = NULL;
 
-	SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
+	pr_debug("%s: timer T2 expired\n", __func__);
+
 	SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
 
 	((struct sctp_association *)asoc)->shutdown_retries++;
@@ -5777,7 +5791,8 @@ sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net,
 {
 	struct sctp_chunk *reply = NULL;
 
-	SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
+	pr_debug("%s: timer T5 expired\n", __func__);
+
 	SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
 
 	reply = sctp_make_abort(asoc, NULL, 0);
@@ -5892,7 +5907,8 @@ sctp_disposition_t sctp_sf_timer_ignore(struct net *net,
 					void *arg,
 					sctp_cmd_seq_t *commands)
 {
-	SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
+	pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
+
 	return SCTP_DISPOSITION_CONSUME;
 }
 
@@ -6102,7 +6118,7 @@ static int sctp_eat_data(const struct sctp_association *asoc,
 	skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
 
 	tsn = ntohl(data_hdr->tsn);
-	SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);
+	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
 
 	/* ASSERT:  Now skb->data is really the user data.  */
 
@@ -6179,12 +6195,12 @@ static int sctp_eat_data(const struct sctp_association *asoc,
 		 */
 		if (sctp_tsnmap_has_gap(map) &&
 		    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
-			SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
+			pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
 			deliver = SCTP_CMD_RENEGE;
 		} else {
-			SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
-					  "rwnd: %d\n", tsn, datalen,
-					  asoc->rwnd);
+			pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
+				 __func__, tsn, datalen, asoc->rwnd);
+
 			return SCTP_IERROR_IGNORE_TSN;
 		}
 	}
@@ -6199,7 +6215,8 @@ static int sctp_eat_data(const struct sctp_association *asoc,
 	if (*sk->sk_prot_creator->memory_pressure) {
 		if (sctp_tsnmap_has_gap(map) &&
 	           (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
-			SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn);
+			pr_debug("%s: under pressure, reneging for tsn:%u\n",
+				 __func__, tsn);
 			deliver = SCTP_CMD_RENEGE;
 		 }
 	}