net: sctp: convert sctp_checksum_disable module param into sctp sysctl

Get rid of the last module parameter for SCTP and make this
configurable via sysctl for SCTP like all the rest of SCTP's
configuration knobs.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ip-sysctl.txt

@@ -1507,6 +1507,14 @@ sack_timeout - INTEGER
 
 	Default: 200
 
+checksum_disable - BOOLEAN
+	Disable SCTP checksum computing and verification for debugging purpose.
+
+	1: Disable checksumming
+	0: Enable checksumming
+
+	Default: 0
+
 valid_cookie_life - INTEGER
 	The default lifetime of the SCTP cookie (in milliseconds).  The cookie
 	is used during association establishment.

include/net/netns/sctp.h

@@ -129,6 +129,9 @@ struct netns_sctp {
 
 	/* Threshold for autoclose timeout, in seconds. */
 	unsigned long max_autoclose;
+
+	/* Flag to disable SCTP checksumming. */
+	int checksum_disable;
 };
 
 #endif /* __NETNS_SCTP_H__ */

include/net/sctp/structs.h

@@ -141,10 +141,6 @@ extern struct sctp_globals {
 	/* This is the sctp port control hash.	*/
 	int port_hashsize;
 	struct sctp_bind_hashbucket *port_hashtable;
-
-	/* Flag to indicate whether computing and verifying checksum
-	 * is disabled. */
-        bool checksum_disable;
 } sctp_globals;
 
 #define sctp_max_instreams		(sctp_globals.max_instreams)
@@ -156,7 +152,6 @@ extern struct sctp_globals {
 #define sctp_assoc_hashtable		(sctp_globals.assoc_hashtable)
 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
-#define sctp_checksum_disable		(sctp_globals.checksum_disable)
 
 /* SCTP Socket type: UDP or TCP style. */
 typedef enum {

net/sctp/input.c

@@ -140,8 +140,8 @@ int sctp_rcv(struct sk_buff *skb)
 	__skb_pull(skb, skb_transport_offset(skb));
 	if (skb->len < sizeof(struct sctphdr))
 		goto discard_it;
-	if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) &&
-		  sctp_rcv_checksum(net, skb) < 0)
+	if (!net->sctp.checksum_disable && !skb_csum_unnecessary(skb) &&
+	    sctp_rcv_checksum(net, skb) < 0)
 		goto discard_it;
 
 	skb_pull(skb, sizeof(struct sctphdr));

net/sctp/output.c

@@ -395,6 +395,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 	int padding;		/* How much padding do we need?  */
 	__u8 has_data = 0;
 	struct dst_entry *dst = tp->dst;
+	struct net *net;
 	unsigned char *auth = NULL;	/* pointer to auth in skb data */
 	__u32 cksum_buf_len = sizeof(struct sctphdr);
 
@@ -541,7 +542,9 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 	 * Note: Adler-32 is no longer applicable, as has been replaced
 	 * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
 	 */
-	if (!sctp_checksum_disable) {
+	net = dev_net(dst->dev);
+
+	if (!net->sctp.checksum_disable) {
 		if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) {
 			__u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
 

net/sctp/protocol.c

@@ -1193,6 +1193,9 @@ static int __net_init sctp_net_init(struct net *net)
 	/* Whether Cookie Preservative is enabled(1) or not(0) */
 	net->sctp.cookie_preserve_enable 	= 1;
 
+	/* Whether SCTP checksumming is disabled(1) or not(0) */
+	net->sctp.checksum_disable		= 0;
+
 	/* Default sctp sockets to use md5 as their hmac alg */
 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
 	net->sctp.sctp_hmac_alg			= "md5";
@@ -1549,6 +1552,4 @@ MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
-module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
-MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
 MODULE_LICENSE("GPL");

net/sctp/sysctl.c

@@ -296,7 +296,15 @@ static struct ctl_table sctp_net_table[] = {
 		.extra1		= &max_autoclose_min,
 		.extra2		= &max_autoclose_max,
 	},
-
+	{
+		.procname	= "checksum_disable",
+		.data		= &init_net.sctp.checksum_disable,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &one,
+	},
 	{ /* sentinel */ }
 };