RFC1144: integration and unit-test

The previously pushed slhc implementation has been modified to compile
and function outside of the kernel. Also debug log messages were added
and datatypes ware matched. The implementation is now ready to be used

Change-Id: I7a638e88a43b3eb9d006751a03ef2570e36613f0

3 files changed, 163 insertions, 88 deletions

diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index 3b5839997..06c12d7d9 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -87,6 +87,7 @@ osmo_sgsn_SOURCES = \
 	gprs_gsup_client.c \
 	sgsn_cdr.c \
 	sgsn_ares.c \
+	slhc.c \
 	oap.c \
 	oap_messages.c \
 	gprs_llc_xid.c \
diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c
index 7d533c060..9f3260d55 100644
--- a/openbsc/src/gprs/sgsn_main.c
+++ b/openbsc/src/gprs/sgsn_main.c
@@ -294,6 +294,11 @@ static struct log_info_cat gprs_categories[] = {
 		.description = "SCCP User Adaptation (SUA)",
 		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
+	[DSLHC] = {
+		.name = "DSLHC",
+		.description = "RFC1144 TCP/IP Header compression (SLHC)",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
 };
 
 static const struct log_info gprs_log_info = {
diff --git a/openbsc/src/gprs/slhc.c b/openbsc/src/gprs/slhc.c
index 27ed25252..cbdf8dbd8 100644
--- a/openbsc/src/gprs/slhc.c
+++ b/openbsc/src/gprs/slhc.c
@@ -50,61 +50,77 @@
  *	driver code belonging close to PPP and SLIP
  */
 
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/types.h>
-#include <linux/string.h>
-#include <linux/errno.h>
-#include <linux/kernel.h>
-#include <net/slhc_vj.h>
-
-#ifdef CONFIG_INET
-/* Entire module is for IP only */
-#include <linux/mm.h>
-#include <linux/socket.h>
-#include <linux/sockios.h>
-#include <linux/termios.h>
-#include <linux/in.h>
-#include <linux/fcntl.h>
-#include <linux/inet.h>
-#include <linux/netdevice.h>
-#include <net/ip.h>
-#include <net/protocol.h>
-#include <net/icmp.h>
-#include <net/tcp.h>
-#include <linux/skbuff.h>
-#include <net/sock.h>
-#include <linux/timer.h>
-#include <asm/uaccess.h>
-#include <net/checksum.h>
-#include <asm/unaligned.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdint.h>
+#include <arpa/inet.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/talloc.h>
+#include <openbsc/slhc.h>
+#include <openbsc/debug.h>
+
+#define ERR_PTR(x) x
+
 
 static unsigned char *encode(unsigned char *cp, unsigned short n);
 static long decode(unsigned char **cpp);
 static unsigned char * put16(unsigned char *cp, unsigned short x);
 static unsigned short pull16(unsigned char **cpp);
 
+/* Replacement for kernel space function ip_fast_csum() */
+static uint16_t ip_fast_csum(uint8_t *iph, int ihl)
+{
+	int i;
+	uint16_t temp;
+	uint32_t accumulator = 0xFFFF;
+
+	for(i=0;i<ihl*2;i++)
+	{
+		temp = ((*iph) << 8)&0xFF00;
+		iph++;
+		temp |= (*iph)&0xFF;
+		iph++;
+
+		accumulator+=temp;
+		if(accumulator>0xFFFF)
+		{
+			accumulator++;
+			accumulator&=0xFFFF;
+		}
+	}
+
+    return (uint16_t)(htons(~accumulator)&0xFFFF);
+}
+
+/* Replacement for kernel space function put_unaligned() */
+static void put_unaligned(uint16_t val, void *ptr)
+{
+	memcpy(ptr,&val,sizeof(val));
+}
+
+
 /* Allocate compression data structure
  *	slots must be in range 0 to 255 (zero meaning no compression)
  * Returns pointer to structure or ERR_PTR() on error.
  */
 struct slcompress *
-slhc_init(int rslots, int tslots)
+slhc_init(const void *ctx, int rslots, int tslots)
 {
 	register short i;
 	register struct cstate *ts;
 	struct slcompress *comp;
 
 	if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
-		return ERR_PTR(-EINVAL);
+		return NULL;
 
-	comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL);
+	comp = (struct slcompress *)talloc_zero_size(ctx,sizeof(struct slcompress));
 	if (! comp)
 		goto out_fail;
 
 	if (rslots > 0) {
 		size_t rsize = rslots * sizeof(struct cstate);
-		comp->rstate = kzalloc(rsize, GFP_KERNEL);
+		comp->rstate = (struct cstate *) talloc_zero_size(ctx, rsize);
 		if (! comp->rstate)
 			goto out_free;
 		comp->rslot_limit = rslots - 1;
@@ -112,7 +128,7 @@ slhc_init(int rslots, int tslots)
 
 	if (tslots > 0) {
 		size_t tsize = tslots * sizeof(struct cstate);
-		comp->tstate = kzalloc(tsize, GFP_KERNEL);
+		comp->tstate = (struct cstate *) talloc_zero_size(ctx, tsize);
 		if (! comp->tstate)
 			goto out_free2;
 		comp->tslot_limit = tslots - 1;
@@ -141,11 +157,11 @@ slhc_init(int rslots, int tslots)
 	return comp;
 
 out_free2:
-	kfree(comp->rstate);
+	talloc_free(comp->rstate);
 out_free:
-	kfree(comp);
+	talloc_free(comp);
 out_fail:
-	return ERR_PTR(-ENOMEM);
+	return NULL;
 }
 
 
@@ -153,16 +169,18 @@ out_fail:
 void
 slhc_free(struct slcompress *comp)
 {
+	DEBUGP(DSLHC, "slhc_free(): Freeing compression states...\n");
+
 	if ( comp == NULLSLCOMPR )
 		return;
 
 	if ( comp->tstate != NULLSLSTATE )
-		kfree( comp->tstate );
+		talloc_free(comp->tstate );
 
 	if ( comp->rstate != NULLSLSTATE )
-		kfree( comp->rstate );
+		talloc_free( comp->rstate );
 
-	kfree( comp );
+	talloc_free( comp );
 }
 
 
@@ -187,6 +205,8 @@ encode(unsigned char *cp, unsigned short n)
 	} else {
 		*cp++ = n;
 	}
+
+	DEBUGP(DSLHC, "encode(): n=%04x\n",n);
 	return cp;
 }
 
@@ -256,6 +276,7 @@ slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
 			comp->sls_o_nontcp++;
 		else
 			comp->sls_o_tcp++;
+		DEBUGP(DSLHC, "slhc_compress(): Not a TCP packat, will not touch...\n");
 		return isize;
 	}
 	/* Extract TCP header */
@@ -271,6 +292,7 @@ slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
 	    ! (th->ack)){
 		/* TCP connection stuff; send as regular IP */
 		comp->sls_o_tcp++;
+		DEBUGP(DSLHC, "slhc_compress(): Packet is part of a TCP connection, will not touch...\n");
 		return isize;
 	}
 	/*
@@ -287,6 +309,9 @@ slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
 	 * states via linear search.  If we don't find a state
 	 * for the datagram, the oldest state is (re-)used.
 	 */
+
+	DEBUGP(DSLHC, "slhc_compress(): Compressible packet detected!\n");
+
 	for ( ; ; ) {
 		if( ip->saddr == cs->cs_ip.saddr
 		 && ip->daddr == cs->cs_ip.daddr
@@ -310,11 +335,14 @@ slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
 	 * state points to the newest and we only need to set
 	 * xmit_oldest to update the lru linkage.
 	 */
+
+	DEBUGP(DSLHC, "slhc_compress(): Header not yet seen, will memorize header for the next turn...\n");
 	comp->sls_o_misses++;
 	comp->xmit_oldest = lcs->cs_this;
 	goto uncompressed;
 
 found:
+		DEBUGP(DSLHC, "slhc_compress(): Header already seen, trying to compress...\n");
 	/*
 	 * Found it -- move to the front on the connection list.
 	 */
@@ -344,6 +372,39 @@ found:
 	 */
 	oth = &cs->cs_tcp;
 
+	/* Display a little more debug information about which of the
+	 * header fields changed unexpectedly */
+	if(ip->version != cs->cs_ip.version)
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: ip->version != cs->cs_ip.version\n");
+	if(ip->ihl != cs->cs_ip.ihl)
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: ip->ihl != cs->cs_ip.ihl\n");
+	if(ip->tos != cs->cs_ip.tos)
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: ip->tos != cs->cs_ip.tos\n");
+	if((ip->frag_off & htons(0x4000)) != (cs->cs_ip.frag_off & htons(0x4000)))
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: (ip->frag_off & htons(0x4000)) != (cs->cs_ip.frag_off & htons(0x4000))\n");
+	if(ip->ttl != cs->cs_ip.ttl)
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: ip->ttl != cs->cs_ip.ttl\n");
+	if(th->doff != cs->cs_tcp.doff)
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: th->doff != cs->cs_tcp.doff\n");
+	if(ip->ihl > 5 && memcmp(ip+1,cs->cs_ipopt,((ip->ihl)-5)*4) != 0) {
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: (ip->ihl > 5 && memcmp(ip+1,cs->cs_ipopt,((ip->ihl)-5)*4) != 0)\n");
+		DEBUGP(DSLHC, "slhc_compress(): ip->ihl = %i\n", ip->ihl);
+		DEBUGP(DSLHC, "slhc_compress(): ip+1 =          %s\n",
+		       osmo_hexdump_nospc((uint8_t*)(ip+1),((ip->ihl)-5)*4));
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: cs->cs_ipopt =  %s\n",
+		       osmo_hexdump_nospc((uint8_t*)(cs->cs_ipopt),((ip->ihl)-5)*4));
+	}
+	if(th->doff > 5 && memcmp(th+1,cs->cs_tcpopt,((th->doff)-5)*4) != 0) {
+		DEBUGP(DSLHC, "slhc_compress(): Unexpected change: (th->doff > 5 && memcmp(th+1,cs->cs_tcpopt,((th->doff)-5)*4) != 0)\n");
+		DEBUGP(DSLHC, "slhc_compress(): th->doff = %i\n", th->doff);
+		DEBUGP(DSLHC, "slhc_compress(): th+1 =          %s\n",
+		       osmo_hexdump_nospc((uint8_t*)(th+1),((th->doff)-5)*4));
+		DEBUGP(DSLHC, "slhc_compress(): cs->cs_tcpopt = %s\n",
+		       osmo_hexdump_nospc((uint8_t*)cs->cs_tcpopt,
+					  ((th->doff)-5)*4));
+	}
+
+
 	if(ip->version != cs->cs_ip.version || ip->ihl != cs->cs_ip.ihl
 	 || ip->tos != cs->cs_ip.tos
 	 || (ip->frag_off & htons(0x4000)) != (cs->cs_ip.frag_off & htons(0x4000))
@@ -351,6 +412,7 @@ found:
 	 || th->doff != cs->cs_tcp.doff
 	 || (ip->ihl > 5 && memcmp(ip+1,cs->cs_ipopt,((ip->ihl)-5)*4) != 0)
 	 || (th->doff > 5 && memcmp(th+1,cs->cs_tcpopt,((th->doff)-5)*4) != 0)){
+		DEBUGP(DSLHC, "slhc_compress(): The header contains unexpected changes, can't compress...\n");
 		goto uncompressed;
 	}
 
@@ -362,6 +424,7 @@ found:
 	 */
 	if(th->urg){
 		deltaS = ntohs(th->urg_ptr);
+		DEBUGP(DSLHC, "slhc_compress(): flag: Urgent Pointer (U) = 1\n");
 		cp = encode(cp,deltaS);
 		changes |= NEW_U;
 	} else if(th->urg_ptr != oth->urg_ptr){
@@ -369,21 +432,29 @@ found:
 		 * implementation should never do this but RFC793
 		 * doesn't prohibit the change so we have to deal
 		 * with it. */
+		DEBUGP(DSLHC, "slhc_compress(): URG not set but urp changed, can't compress...\n");
 		goto uncompressed;
 	}
 	if((deltaS = ntohs(th->window) - ntohs(oth->window)) != 0){
+		DEBUGP(DSLHC, "slhc_compress(): flag: Delta Window (W) = 1\n");
 		cp = encode(cp,deltaS);
 		changes |= NEW_W;
 	}
 	if((deltaA = ntohl(th->ack_seq) - ntohl(oth->ack_seq)) != 0L){
-		if(deltaA > 0x0000ffff)
+		if(deltaA > 0x0000ffff)	{
+			DEBUGP(DSLHC, "slhc_compress(): (deltaA = ntohl(th->ack_seq) - ntohl(oth->ack_seq)) != 0L, can't compress...\n");
 			goto uncompressed;
+		}
+		DEBUGP(DSLHC, "slhc_compress(): flag: Delta Ack (A) = 1\n");
 		cp = encode(cp,deltaA);
 		changes |= NEW_A;
 	}
 	if((deltaS = ntohl(th->seq) - ntohl(oth->seq)) != 0L){
-		if(deltaS > 0x0000ffff)
+		if(deltaS > 0x0000ffff)	{
+			DEBUGP(DSLHC, "slhc_compress(): (deltaS = ntohl(th->seq) - ntohl(oth->seq)) != 0L, can't compress...\n");
 			goto uncompressed;
+		}
+		DEBUGP(DSLHC, "slhc_compress(): flag: Delta Sequence (S) = 1\n");
 		cp = encode(cp,deltaS);
 		changes |= NEW_S;
 	}
@@ -399,17 +470,21 @@ found:
 		if(ip->tot_len != cs->cs_ip.tot_len &&
 		   ntohs(cs->cs_ip.tot_len) == hlen)
 			break;
+		DEBUGP(DSLHC, "slhc_compress(): Retransmitted packet detected, can't compress...\n");
 		goto uncompressed;
 	case SPECIAL_I:
 	case SPECIAL_D:
 		/* actual changes match one of our special case encodings --
 		 * send packet uncompressed.
 		 */
+		DEBUGP(DSLHC, "slhc_compress(): Special case detected, can't compress...\n");
 		goto uncompressed;
 	case NEW_S|NEW_A:
 		if(deltaS == deltaA &&
 		    deltaS == ntohs(cs->cs_ip.tot_len) - hlen){
 			/* special case for echoed terminal traffic */
+			DEBUGP(DSLHC, "slhc_compress(): Special case for echoed terminal traffic detected...\n");
+			DEBUGP(DSLHC, "slhc_compress(): flag: Delta Sequence (S) = 1, Delta Window (W) = 1, Urgent Pointer (U) = 1\n");
 			changes = SPECIAL_I;
 			cp = new_seq;
 		}
@@ -417,6 +492,8 @@ found:
 	case NEW_S:
 		if(deltaS == ntohs(cs->cs_ip.tot_len) - hlen){
 			/* special case for data xfer */
+			DEBUGP(DSLHC, "slhc_compress(): Special case for data xfer detected...\n");
+			DEBUGP(DSLHC, "slhc_compress(): flag: Delta Sequence (S) = 1, Delta Ack (A) = 1, Delta Window (W) = 1, Urgent Pointer (U) = 1\n");
 			changes = SPECIAL_D;
 			cp = new_seq;
 		}
@@ -424,11 +501,14 @@ found:
 	}
 	deltaS = ntohs(ip->id) - ntohs(cs->cs_ip.id);
 	if(deltaS != 1){
+		DEBUGP(DSLHC, "slhc_compress(): flag: Delta IP ID (I) = 1\n");
 		cp = encode(cp,deltaS);
 		changes |= NEW_I;
 	}
-	if(th->psh)
+	if(th->psh) {
+		DEBUGP(DSLHC, "slhc_compress(): flag: Push (P) = 1\n");
 		changes |= TCP_PUSH_BIT;
+	}
 	/* Grab the cksum before we overwrite it below.  Then update our
 	 * state with this packet's header.
 	 */
@@ -445,6 +525,7 @@ found:
 	if(compress_cid == 0 || comp->xmit_current != cs->cs_this){
 		cp = ocp;
 		*cpp = ocp;
+		DEBUGP(DSLHC, "slhc_compress(): flag: Connection number (C) = 1\n");
 		*cp++ = changes | NEW_C;
 		*cp++ = cs->cs_this;
 		comp->xmit_current = cs->cs_this;
@@ -456,6 +537,10 @@ found:
 	*(__sum16 *)cp = csum;
 	cp += 2;
 /* deltaS is now the size of the change section of the compressed header */
+
+	DEBUGP(DSLHC, "slhc_compress(): Delta-list length (deltaS) = %li\n",deltaS);
+	DEBUGP(DSLHC, "slhc_compress(): Original header len (hlen) = %i\n",hlen);
+
 	memcpy(cp,new_seq,deltaS);	/* Write list of deltas */
 	memcpy(cp+deltaS,icp+hlen,isize-hlen);
 	comp->sls_o_compressed++;
@@ -467,6 +552,7 @@ found:
 	 * to use on future compressed packets in the protocol field).
 	 */
 uncompressed:
+	DEBUGP(DSLHC, "slhc_compress(): Packet will be sent uncompressed...\n");
 	memcpy(&cs->cs_ip,ip,20);
 	memcpy(&cs->cs_tcp,th,20);
 	if (ip->ihl > 5)
@@ -538,6 +624,8 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
 
 	switch(changes & SPECIALS_MASK){
 	case SPECIAL_I:		/* Echoed terminal traffic */
+		DEBUGP(DSLHC, "slhc_uncompress(): Echoed terminal traffic detected\n");
+
 		{
 		register short i;
 		i = ntohs(ip->tot_len) - hdrlen;
@@ -547,11 +635,13 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
 		break;
 
 	case SPECIAL_D:			/* Unidirectional data */
+		DEBUGP(DSLHC, "slhc_uncompress(): Unidirectional data detected\n");
 		thp->seq = htonl( ntohl(thp->seq) +
 				  ntohs(ip->tot_len) - hdrlen);
 		break;
 
 	default:
+		DEBUGP(DSLHC, "slhc_uncompress(): default packet type detected\n");
 		if(changes & NEW_U){
 			thp->urg = 1;
 			if((x = decode(&cp)) == -1) {
@@ -601,6 +691,7 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
 	ip->tot_len = htons(len);
 	ip->check = 0;
 
+	DEBUGP(DSLHC, "slhc_uncompress(): making space for the reconstructed header...\n");
 	memmove(icp + hdrlen, cp, len - hdrlen);
 
 	cp = icp;
@@ -625,6 +716,7 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
 
 	return len;
 bad:
+	DEBUGP(DSLHC, "slhc_uncompress(): bad packet detected!\n");
 	comp->sls_i_error++;
 	return slhc_toss( comp );
 }
@@ -641,6 +733,7 @@ slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
 	if(isize < 20) {
 		/* The packet is shorter than a legal IP header */
 		comp->sls_i_runt++;
+		DEBUGP(DSLHC, "slhc_remember(): The packet is shorter than a legal IP header ==> slhc_toss()\n");
 		return slhc_toss( comp );
 	}
 	/* Peek at the IP header's IHL field to find its length */
@@ -648,6 +741,7 @@ slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
 	if(ihl < 20 / 4){
 		/* The IP header length field is too small */
 		comp->sls_i_runt++;
+		DEBUGP(DSLHC, "slhc_remember(): The IP header length field is too small ==> slhc_toss()\n");
 		return slhc_toss( comp );
 	}
 	index = icp[9];
@@ -656,10 +750,12 @@ slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
 	if (ip_fast_csum(icp, ihl)) {
 		/* Bad IP header checksum; discard */
 		comp->sls_i_badcheck++;
+		DEBUGP(DSLHC, "slhc_remember(): Bad IP header checksum; discard ==> slhc_toss()\n");
 		return slhc_toss( comp );
 	}
 	if(index > comp->rslot_limit) {
 		comp->sls_i_error++;
+		DEBUGP(DSLHC, "slhc_remember(): index > comp->rslot_limit ==> slhc_toss()\n");
 		return slhc_toss(comp);
 	}
 
@@ -683,6 +779,7 @@ slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
 int
 slhc_toss(struct slcompress *comp)
 {
+	DEBUGP(DSLHC, "slhc_toss(): Reset compression state...\n");
 	if ( comp == NULLSLCOMPR )
 		return 0;
 
@@ -690,55 +787,27 @@ slhc_toss(struct slcompress *comp)
 	return 0;
 }
 
-#else /* CONFIG_INET */
-
-int
-slhc_toss(struct slcompress *comp)
-{
-  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_toss");
-  return -EINVAL;
-}
-int
-slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
+void slhc_i_status(struct slcompress *comp)
 {
-  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_uncompress");
-  return -EINVAL;
-}
-int
-slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
-	unsigned char *ocp, unsigned char **cpp, int compress_cid)
-{
-  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_compress");
-  return -EINVAL;
-}
-
-int
-slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
-{
-  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_remember");
-  return -EINVAL;
+	if (comp != NULLSLCOMPR) {
+		DEBUGP(DSLHC, "slhc_i_status(): %d Cmp, %d Uncmp, %d Bad, %d Tossed\n",
+			comp->sls_i_compressed,
+			comp->sls_i_uncompressed,
+			comp->sls_i_error,
+			comp->sls_i_tossed);
+	}
 }
 
-void
-slhc_free(struct slcompress *comp)
+void slhc_o_status(struct slcompress *comp)
 {
-  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_free");
-}
-struct slcompress *
-slhc_init(int rslots, int tslots)
-{
-  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_init");
-  return NULL;
+	if (comp != NULLSLCOMPR) {
+		DEBUGP(DSLHC, "slhc_o_status(): %d Cmp, %d Uncmp, %d AsIs, %d NotTCP %d Searches, %d Misses\n",
+			comp->sls_o_compressed,
+			comp->sls_o_uncompressed,
+			comp->sls_o_tcp,
+			comp->sls_o_nontcp,
+			comp->sls_o_searches,
+			comp->sls_o_misses);
+	}
 }
 
-#endif /* CONFIG_INET */
-
-/* VJ header compression */
-EXPORT_SYMBOL(slhc_init);
-EXPORT_SYMBOL(slhc_free);
-EXPORT_SYMBOL(slhc_remember);
-EXPORT_SYMBOL(slhc_compress);
-EXPORT_SYMBOL(slhc_uncompress);
-EXPORT_SYMBOL(slhc_toss);
-
-MODULE_LICENSE("Dual BSD/GPL");