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>
diff --git a/net/sctp/input.c b/net/sctp/input.c
index fa91aff..b9a25e1 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -140,8 +140,8 @@
 	__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));
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 5a55c55d..cdb5f49 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -395,6 +395,7 @@
 	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 @@
 	 * Note: Adler-32 is no longer applicable, as has been replaced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);
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index b52ec25..a570a63 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1193,6 +1193,9 @@
 	/* 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_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");
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 1906747..754809a 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -296,7 +296,15 @@
 		.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 */ }
 };