Allow to use adler32 for SCTP

index befc8d2..9111f52 100644
@@ -1,6 +1,7 @@
 /* SCTP kernel reference Implementation
  * Copyright (c) 1999-2001 Motorola, Inc.
  * Copyright (c) 2001-2003 International Business Machines, Corp.
+ * Copyright (c) 2011 Holger Hans Peter Freyther
  *
  * This file is part of the SCTP kernel reference Implementation
  *

@@ -34,6 +35,7 @@
  *    Dinakaran Joseph
  *    Jon Grimm <[email protected]>
  *    Sridhar Samudrala <[email protected]>
+ *    Holger Hans Peter Freyther <[email protected]>
  *
  * Rewritten to use libcrc32c by:
  *    Vlad Yasevich <[email protected]>

@@ -45,6 +47,7 @@
 #include <linux/types.h>
 #include <net/sctp/sctp.h>
 #include <linux/crc32c.h>
+#include <linux/zutil.h>
 
 static inline __u32 sctp_crc32c(__u32 crc, u8 *buffer, u16 length)
 {

@@ -81,3 +84,35 @@ static inline __le32 sctp_end_cksum(__be32 crc32)
 {
 	return cpu_to_le32(~crc32);
 }
+
+static inline __u32 sctp_start_cksum_adler(__u8 *buffer, __u16 length)
+{
+	__u32 adler = 1;
+	__u8  zero[sizeof(__u32)] = {0};
+
+	/* Optimize this routine to be SCTP specific, knowing how
+	 * to skip the checksum field of the SCTP header.
+	 */
+
+	/* Calculate adler32 up to the checksum. */
+	adler = zlib_adler32(adler, buffer,
+				sizeof(struct sctphdr) -sizeof(__u32));
+
+	/* Skip checksum field of the header. */
+	adler = zlib_adler32(adler, zero, sizeof(__u32));
+
+	/* Calculate the rest of the adler32. */
+	adler = zlib_adler32(adler, &buffer[sizeof(struct sctphdr)],
+				length - sizeof(struct sctphdr));
+	return adler;
+}
+
+static inline __u32 sctp_update_cksum_adler(__u8 *buffer, __u16 len, __u32 a32)
+{
+	return zlib_adler32(a32, buffer, len);
+}
+
+static inline __u32 sctp_end_cksum_adler(__u32 a32)
+{
+	return htonl(a32);
+}

index cc9185c..d44eb7a 100644
@@ -236,6 +236,9 @@ extern struct sctp_globals {
 	 * bits is an indicator of when to send and window update SACK.
 	 */
 	int rwnd_update_shift;
+
+	/* Allow Adler32 as Checksum fallback */
+	int allow_adler32;
 } sctp_globals;
 
 #define sctp_rto_initial		(sctp_globals.rto_initial)

@@ -271,6 +274,7 @@ extern struct sctp_globals {
 #define sctp_auth_enable		(sctp_globals.auth_enable)
 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
 #define sctp_rwnd_upd_shift		(sctp_globals.rwnd_update_shift)
+#define sctp_allow_adler32_csum		(sctp_globals.allow_adler32)
 
 /* SCTP Socket type: UDP or TCP style. */
 typedef enum {

@@ -338,6 +342,8 @@ struct sctp_sock {
 	__u32 adaptation_ind;
 	__u32 pd_point;
 
+	__u8 cksum_adler;
+
 	atomic_t pd_mode;
 	/* Receive to here while partial delivery is in effect. */
 	struct sk_buff_head pd_lobby;

index 2b2769c..427da93 100644
@@ -103,6 +103,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_GET_LOCAL_ADDRS	109		/* Get all local addresss. */
 #define SCTP_SOCKOPT_CONNECTX	110		/* CONNECTX requests. */
 #define SCTP_SOCKOPT_CONNECTX3	111	/* CONNECTX requests (updated) */
+#define SCTP_COMPAT_ADLER_CRC	112	/* User ADLER32 for the checksum. */
 
 /*
  * 5.2.1 SCTP Initiation Structure (SCTP_INIT)

88 lines not on this page · raw message

index 60600d3..02b2f26 100644
@@ -2,6 +2,7 @@
  * (C) Copyright IBM Corp. 2001, 2004
  * Copyright (c) 1999-2000 Cisco, Inc.
  * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2011 Holger Hans Peter Freyther
  *
  * This file is part of the SCTP kernel implementation
  *

@@ -36,6 +37,7 @@
  *    Karl Knutson          <[email protected]>
  *    Jon Grimm             <[email protected]>
  *    Sridhar Samudrala     <[email protected]>
+ *    Holger Freyther       <[email protected]>
  *
  * Any bugs reported given to us we will try to fix... any fixes shared will
  * be incorporated into the next SCTP release.

@@ -502,12 +504,21 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 	 */
 	if (!sctp_checksum_disable &&
 	    !(dst->dev->features & (NETIF_F_NO_CSUM | NETIF_F_SCTP_CSUM))) {
-		__u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
-
 		/* 3) Put the resultant value into the checksum field in the
 		 *    common header, and leave the rest of the bits unchanged.
 		 */
-		sh->checksum = sctp_end_cksum(crc32);
+		__u32 crc32;
+
+		if (sctp_sk(sk)->cksum_adler && sctp_allow_adler32_csum) {
+			crc32 = sctp_start_cksum_adler((__u8 *)sh,
+							cksum_buf_len);
+			crc32 = sctp_end_cksum_adler(crc32);
+		} else {
+			crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
+			crc32 = sctp_end_cksum(crc32);
+		}
+
+		sh->checksum = crc32;
 	} else {
 		if (dst->dev->features & NETIF_F_SCTP_CSUM) {
 			/* no need to seed psuedo checksum for SCTP */

index e58f947..f078ef6 100644
@@ -1397,4 +1397,7 @@ MODULE_AUTHOR("Linux Kernel SCTP developers <[email protected]
 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_param_named(adler_checksums, sctp_allow_adler32_csum, bool, 0644);
+MODULE_PARM_DESC(adler_checksums,
+		"Allow to use adler32 checksums for historic reasons.");
 MODULE_LICENSE("GPL");

index a09b0dd..e47e39e 100644
@@ -5,6 +5,7 @@
  * Copyright (c) 2001-2003 Intel Corp.
  * Copyright (c) 2001-2002 Nokia, Inc.
  * Copyright (c) 2001 La Monte H.P. Yarroll
+ * Copyright (c) 2011 Holger Hans Peter Freyther
  *
  * This file is part of the SCTP kernel implementation
  *

@@ -52,6 +53,7 @@
  *    Ryan Layer	    <[email protected]>
  *    Anup Pemmaiah         <[email protected]>
  *    Kevin Gao             <[email protected]>
+ *    Holger Freyther       <[email protected]>
  *
  * Any bugs reported given to us we will try to fix... any fixes shared will
  * be incorporated into the next SCTP release.

@@ -3343,6 +3345,23 @@ static int sctp_setsockopt_del_key(struct sock *sk,
 
 }
 
+static int sctp_setsockopt_adler_crc(struct sock *sk,
+					char __user *optval,
+					int optlen)
+{
+	int val;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+	if (get_user(val, (int __user *)optval))
+		return -EFAULT;
+	if (!sctp_allow_adler32_csum)
+		return -EACCES;
+
+	sctp_sk(sk)->cksum_adler = 1;
+	return 0;
+}
+
 
 /* API 6.2 setsockopt(), getsockopt()
  *

@@ -3490,6 +3509,9 @@ SCTP_STATIC int sctp_setsockopt(struct sock *sk, int level, int optname,
 	case SCTP_AUTH_DELETE_KEY:
 		retval = sctp_setsockopt_del_key(sk, optval, optlen);
 		break;
+	case SCTP_COMPAT_ADLER_CRC:
+		retval = sctp_setsockopt_adler_crc(sk, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;

@@ -6490,6 +6512,7 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
 	pp = sctp_sk(oldsk)->bind_hash;
 	sk_add_bind_node(newsk, &pp->owner);
 	sctp_sk(newsk)->bind_hash = pp;
+	sctp_sk(newsk)->cksum_adler = sctp_sk(oldsk)->cksum_adler;
 	inet_sk(newsk)->inet_num = inet_sk(oldsk)->inet_num;
 	sctp_spin_unlock(&head->lock);
 	sctp_local_bh_enable();