backout OS-6878 mac_fix_cksum is incomplete (needs more work)

6 files changed, 188 insertions, 332 deletions

diff --git a/usr/src/uts/common/inet/ip/ip6.c b/usr/src/uts/common/inet/ip/ip6.c
index 20056edfad..7f30aaa81d 100644
--- a/usr/src/uts/common/inet/ip/ip6.c
+++ b/usr/src/uts/common/inet/ip/ip6.c
@@ -2730,6 +2730,112 @@ done:
 }
 
 /*
+ * Try to determine where and what are the IPv6 header length and
+ * pointer to nexthdr value for the upper layer protocol (or an
+ * unknown next hdr).
+ *
+ * Parameters returns a pointer to the nexthdr value;
+ * Must handle malformed packets of various sorts.
+ * Function returns failure for malformed cases.
+ */
+boolean_t
+ip_hdr_length_nexthdr_v6(mblk_t *mp, ip6_t *ip6h, uint16_t *hdr_length_ptr,
+    uint8_t **nexthdrpp)
+{
+	uint16_t length;
+	uint_t	ehdrlen;
+	uint8_t	*nexthdrp;
+	uint8_t *whereptr;
+	uint8_t *endptr;
+	ip6_dest_t *desthdr;
+	ip6_rthdr_t *rthdr;
+	ip6_frag_t *fraghdr;
+
+	ASSERT(IPH_HDR_VERSION(ip6h) == IPV6_VERSION);
+	length = IPV6_HDR_LEN;
+	whereptr = ((uint8_t *)&ip6h[1]); /* point to next hdr */
+	endptr = mp->b_wptr;
+
+	nexthdrp = &ip6h->ip6_nxt;
+	while (whereptr < endptr) {
+		/* Is there enough left for len + nexthdr? */
+		if (whereptr + MIN_EHDR_LEN > endptr)
+			break;
+
+		switch (*nexthdrp) {
+		case IPPROTO_HOPOPTS:
+		case IPPROTO_DSTOPTS:
+			/* Assumes the headers are identical for hbh and dst */
+			desthdr = (ip6_dest_t *)whereptr;
+			ehdrlen = 8 * (desthdr->ip6d_len + 1);
+			if ((uchar_t *)desthdr +  ehdrlen > endptr)
+				return (B_FALSE);
+			nexthdrp = &desthdr->ip6d_nxt;
+			break;
+		case IPPROTO_ROUTING:
+			rthdr = (ip6_rthdr_t *)whereptr;
+			ehdrlen =  8 * (rthdr->ip6r_len + 1);
+			if ((uchar_t *)rthdr +  ehdrlen > endptr)
+				return (B_FALSE);
+			nexthdrp = &rthdr->ip6r_nxt;
+			break;
+		case IPPROTO_FRAGMENT:
+			fraghdr = (ip6_frag_t *)whereptr;
+			ehdrlen = sizeof (ip6_frag_t);
+			if ((uchar_t *)&fraghdr[1] > endptr)
+				return (B_FALSE);
+			nexthdrp = &fraghdr->ip6f_nxt;
+			break;
+		case IPPROTO_NONE:
+			/* No next header means we're finished */
+		default:
+			*hdr_length_ptr = length;
+			*nexthdrpp = nexthdrp;
+			return (B_TRUE);
+		}
+		length += ehdrlen;
+		whereptr += ehdrlen;
+		*hdr_length_ptr = length;
+		*nexthdrpp = nexthdrp;
+	}
+	switch (*nexthdrp) {
+	case IPPROTO_HOPOPTS:
+	case IPPROTO_DSTOPTS:
+	case IPPROTO_ROUTING:
+	case IPPROTO_FRAGMENT:
+		/*
+		 * If any know extension headers are still to be processed,
+		 * the packet's malformed (or at least all the IP header(s) are
+		 * not in the same mblk - and that should never happen.
+		 */
+		return (B_FALSE);
+
+	default:
+		/*
+		 * If we get here, we know that all of the IP headers were in
+		 * the same mblk, even if the ULP header is in the next mblk.
+		 */
+		*hdr_length_ptr = length;
+		*nexthdrpp = nexthdrp;
+		return (B_TRUE);
+	}
+}
+
+/*
+ * Return the length of the IPv6 related headers (including extension headers)
+ * Returns a length even if the packet is malformed.
+ */
+int
+ip_hdr_length_v6(mblk_t *mp, ip6_t *ip6h)
+{
+	uint16_t hdr_len;
+	uint8_t	*nexthdrp;
+
+	(void) ip_hdr_length_nexthdr_v6(mp, ip6h, &hdr_len, &nexthdrp);
+	return (hdr_len);
+}
+
+/*
  * Parse and process any hop-by-hop or destination options.
  *
  * Assumes that q is an ill read queue so that ICMP errors for link-local
diff --git a/usr/src/uts/common/inet/ip/ip6_output.c b/usr/src/uts/common/inet/ip/ip6_output.c
index 23484af98c..dc074454e3 100644
--- a/usr/src/uts/common/inet/ip/ip6_output.c
+++ b/usr/src/uts/common/inet/ip/ip6_output.c
@@ -773,8 +773,6 @@ ip_output_sw_cksum_v6(mblk_t *mp, ip6_t *ip6h, ip_xmit_attr_t *ixa)
 	/* ULP puts the checksum field is in the first mblk */
 	ASSERT(((uchar_t *)cksump) + sizeof (uint16_t) <= mp->b_wptr);
 
-	DB_CKSUMOCSUM(mp) = *cksump;
-
 	/*
 	 * We accumulate the pseudo header checksum in cksum.
 	 * This is pretty hairy code, so watch close.  One
@@ -806,11 +804,7 @@ ip_output_sw_cksum_v6(mblk_t *mp, ip6_t *ip6h, ip_xmit_attr_t *ixa)
 #undef	iphs
 }
 
-/*
- * Sadly, removing this unused global variable will actually break the build.
- * Compiling the "ip" module explicitly checks that no global variables
- * are added or removed.
- */
+/* There are drivers that can't do partial checksum for ICMPv6 */
 int nxge_cksum_workaround = 1;
 
 /*
@@ -892,9 +886,6 @@ ip_output_cksum_v6(iaflags_t ixaflags, mblk_t *mp, ip6_t *ip6h,
 	/* ULP puts the checksum field is in the first mblk */
 	ASSERT(((uchar_t *)cksump) + sizeof (uint16_t) <= mp->b_wptr);
 
-	/* Record original checksum field in case needed within MAC */
-	DB_CKSUMOCSUM(mp) = *cksump;
-
 	/*
 	 * Underlying interface supports hardware checksum offload for
 	 * the payload; leave the payload checksum for the hardware to
@@ -914,7 +905,8 @@ ip_output_cksum_v6(iaflags_t ixaflags, mblk_t *mp, ip6_t *ip6h,
 		DB_CKSUMFLAGS(mp) |= HCK_FULLCKSUM;
 		return (B_TRUE);
 	}
-	if (hck_flags & HCKSUM_INET_PARTIAL) {
+	if (((hck_flags) & HCKSUM_INET_PARTIAL) &&
+	    (protocol != IPPROTO_ICMPV6 || !nxge_cksum_workaround)) {
 		/*
 		 * Partial checksum offload has been enabled.  Fill
 		 * the checksum field in the protocol header with the
diff --git a/usr/src/uts/common/io/mac/mac_util.c b/usr/src/uts/common/io/mac/mac_util.c
index 814fbecfd1..a877ca258c 100644
--- a/usr/src/uts/common/io/mac/mac_util.c
+++ b/usr/src/uts/common/io/mac/mac_util.c
@@ -48,7 +48,6 @@
 #include <inet/sadb.h>
 #include <inet/ipsecesp.h>
 #include <inet/ipsecah.h>
-#include <inet/sctp_ip.h>
 
 /*
  * Copy an mblk, preserving its hardware checksum flags.
@@ -89,164 +88,10 @@ mac_copymsgchain_cksum(mblk_t *mp)
 	return (nmp);
 }
 
-static void
-mac_ipv4_chksum(mblk_t *mp, uint32_t offset, ipha_t *ipha)
-{
-	uint8_t proto;
-	ipaddr_t src, dst;
-	uint16_t len;
-	uint32_t cksum;
-	uint16_t *up;
-
-	/*
-	 * Pointer to checksum field in ULP header.
-	 */
-	proto = ipha->ipha_protocol;
-	ASSERT(ipha->ipha_version_and_hdr_length == IP_SIMPLE_HDR_VERSION);
-
-	switch (proto) {
-	case IPPROTO_TCP:
-		/* LINTED: improper alignment cast */
-		up = IPH_TCPH_CHECKSUMP(ipha, IP_SIMPLE_HDR_LENGTH);
-		cksum = IP_TCP_CSUM_COMP;
-		break;
-	case IPPROTO_UDP:
-		/* LINTED: improper alignment cast */
-		up = IPH_UDPH_CHECKSUMP(ipha, IP_SIMPLE_HDR_LENGTH);
-		cksum = IP_UDP_CSUM_COMP;
-		break;
-	case IPPROTO_SCTP: {
-		sctp_hdr_t *sctph;
-
-		ASSERT(MBLKL(mp) >= (IP_SIMPLE_HDR_LENGTH + sizeof (*sctph)));
-		sctph = (sctp_hdr_t *)(mp->b_rptr + IP_SIMPLE_HDR_LENGTH);
-		/*
-		 * Zero out the checksum field to ensure proper checksum
-		 * calculation.
-		 */
-		sctph->sh_chksum = 0;
-		sctph->sh_chksum = sctp_cksum(mp, IP_SIMPLE_HDR_LENGTH);
-		return;
-	}
-	default:
-		return;
-	}
-
-	/*
-	 * Pseudo-header checksum.
-	 */
-	src = ipha->ipha_src;
-	dst = ipha->ipha_dst;
-	len = ntohs(ipha->ipha_length) - IP_SIMPLE_HDR_LENGTH;
-
-	cksum += (dst >> 16) + (dst & 0xFFFF) + (src >> 16) + (src & 0xFFFF);
-	cksum += htons(len);
-
-	/*
-	 * The checksum value stored in the packet needs to be correct. Compute
-	 * it here.
-	 */
-	*up = 0;
-	cksum = IP_CSUM(mp, IP_SIMPLE_HDR_LENGTH + offset, cksum);
-	*up = (uint16_t)(cksum ? cksum : ~cksum);
-}
-
-static void
-mac_ipv6_chksum(mblk_t *mp, uint32_t offset, ip6_t *ip6h)
-{
-	uint8_t proto;
-	uint32_t cksum;
-	uint16_t *up;
-	uint16_t ip_hdr_length = ip_hdr_length_v6(mp, ip6h);
-
-#define	iphs	((uint16_t *)ip6h)
-
-	/*
-	 * Pointer to checksum field in ULP header.
-	 */
-	proto = ip6h->ip6_nxt;
-
-	/*
-	 * The IPv6 SW checksum code calculation (ip_output_cksum_v6) handles
-	 * IXAF_SET_RAW_CKSUM, but that is never a factor when full HW checksum
-	 * offload is in use, so we can't worry about it here either. We have
-	 * to calculate the noraml ICMPv6 checksum.
-	 */
-
-	switch (proto) {
-	case IPPROTO_TCP:
-		/* LINTED: improper alignment cast */
-		up = IPH_TCPH_CHECKSUMP(ip6h, ip_hdr_length);
-		cksum = IP_TCP_CSUM_COMP;
-		break;
-
-	case IPPROTO_UDP:
-		/* LINTED: improper alignment cast */
-		up = IPH_UDPH_CHECKSUMP(ip6h, ip_hdr_length);
-		cksum = IP_UDP_CSUM_COMP;
-		break;
-
-	case IPPROTO_SCTP: {
-		sctp_hdr_t *sctph;
-
-		ASSERT(MBLKL(mp) >= (ip_hdr_length + sizeof (*sctph)));
-		sctph = (sctp_hdr_t *)(mp->b_rptr + ip_hdr_length);
-		/*
-		 * Zero out the checksum field to ensure proper
-		 * checksum calculation.
-		 */
-		sctph->sh_chksum = 0;
-		sctph->sh_chksum = sctp_cksum(mp, ip_hdr_length);
-		return;
-	}
-
-	case IPPROTO_ICMPV6:
-		up = IPH_ICMPV6_CHECKSUMP(ip6h, ip_hdr_length);
-		cksum = IP_ICMPV6_CSUM_COMP;    /* Pseudo-header cksum */
-		break;
-
-	default:
-		return;
-	}
-
-	/* ULP assumes the checksum field is in the first mblk */
-	ASSERT(((uchar_t *)up) + sizeof (uint16_t) <= mp->b_wptr);
-
-	/*
-	 * Restore the original entry in the checksum field so that we can
-	 * properly calculate the checksum.
-	 */
-	*up = DB_CKSUMOCSUM(mp);
-
-	/*
-	 * We accumulate the pseudo header checksum in cksum. This is pretty
-	 * hairy code, so watch close. One thing to keep in mind is that UDP
-	 * and TCP have stored their respective datagram lengths in their
-	 * checksum fields. This lines things up real nice.
-	 */
-	cksum += iphs[4] + iphs[5] + iphs[6] + iphs[7] + iphs[8] + iphs[9] +
-	    iphs[10] + iphs[11] + iphs[12] + iphs[13] + iphs[14] + iphs[15] +
-	    iphs[16] + iphs[17] + iphs[18] + iphs[19];
-	cksum = IP_CSUM(mp, ip_hdr_length + offset, cksum);
-
-	/* For UDP/IPv6 a zero UDP checksum is not allowed. Change to 0xffff */
-	if (proto == IPPROTO_UDP && cksum == 0)
-		cksum = ~cksum;
-	*up = cksum;
-
-#undef	iphs
-	/* No IP header checksum for IPv6 */
-}
-
 /*
  * Process the specified mblk chain for proper handling of hardware
  * checksum offload. This routine is invoked for loopback traffic
- * between MAC clients. The specific issue is that the upstack code (IP) may
- * not calculate any checksums, or perhaps a partial checksum, based on the
- * advertised HW checksum offload features of the underlying NIC below the
- * netstack, but since we're looping back the packet without ever hitting the
- * NIC, we may have to calculate the checksums ourselves at this point.
- *
+ * between MAC clients.
  * The function handles a NULL mblk chain passed as argument.
  */
 mblk_t *
@@ -277,7 +122,6 @@ mac_fix_cksum(mblk_t *mp_chain)
 				continue;
 			mp1->b_next = mp->b_next;
 			mp->b_next = NULL;
-			DB_CKSUMOCSUM(mp1) = DB_CKSUMOCSUM(mp);
 			freemsg(mp);
 			if (prev != NULL)
 				prev->b_next = mp1;
@@ -329,67 +173,98 @@ mac_fix_cksum(mblk_t *mp_chain)
 		}
 
 		if (flags & (HCK_FULLCKSUM | HCK_IPV4_HDRCKSUM)) {
+			ipha_t *ipha = NULL;
+
 			/*
 			 * In order to compute the full and header
 			 * checksums, we need to find and parse
-			 * the IP/IPv6 and/or ULP headers.
+			 * the IP and/or ULP headers.
 			 */
 
 			sap = (sap < ETHERTYPE_802_MIN) ? 0 : sap;
 
-			if (sap == ETHERTYPE_IP) {
+			/*
+			 * IP header.
+			 */
+			if (sap != ETHERTYPE_IP)
+				continue;
+
+			ASSERT(MBLKL(mp) >= offset + sizeof (ipha_t));
+			/* LINTED: improper alignment cast */
+			ipha = (ipha_t *)(mp->b_rptr + offset);
+
+			if (flags & HCK_FULLCKSUM) {
+				ipaddr_t src, dst;
+				uint32_t cksum;
+				uint16_t *up;
+				uint8_t proto;
+
 				/*
-				 * IP header.
+				 * Pointer to checksum field in ULP header.
 				 */
-				ipha_t *ipha;
+				proto = ipha->ipha_protocol;
+				ASSERT(ipha->ipha_version_and_hdr_length ==
+				    IP_SIMPLE_HDR_VERSION);
+
+				switch (proto) {
+				case IPPROTO_TCP:
+					/* LINTED: improper alignment cast */
+					up = IPH_TCPH_CHECKSUMP(ipha,
+					    IP_SIMPLE_HDR_LENGTH);
+					break;
+
+				case IPPROTO_UDP:
+					/* LINTED: improper alignment cast */
+					up = IPH_UDPH_CHECKSUMP(ipha,
+					    IP_SIMPLE_HDR_LENGTH);
+					break;
+
+				default:
+					cmn_err(CE_WARN, "mac_fix_cksum: "
+					    "unexpected protocol: %d", proto);
+					continue;
+				}
 
-				ASSERT(MBLKL(mp) >= offset + sizeof (ipha_t));
-				/* LINTED: improper alignment cast */
-				ipha = (ipha_t *)(mp->b_rptr + offset);
+				/*
+				 * Pseudo-header checksum.
+				 */
+				src = ipha->ipha_src;
+				dst = ipha->ipha_dst;
+				len = ntohs(ipha->ipha_length) -
+				    IP_SIMPLE_HDR_LENGTH;
 
-				if (flags & HCK_FULLCKSUM) {
-					mac_ipv4_chksum(mp, offset, ipha);
-					/*
-					 * Flag the packet so that it appears
-					 * that the checksum has already been
-					 * verified by the hardware.
-					 */
-					flags &= ~HCK_FULLCKSUM;
-					flags |= HCK_FULLCKSUM_OK;
-					value = 0;
-				}
+				cksum = (dst >> 16) + (dst & 0xFFFF) +
+				    (src >> 16) + (src & 0xFFFF);
+				cksum += htons(len);
 
-				if (flags & HCK_IPV4_HDRCKSUM) {
-					ASSERT(ipha != NULL);
-					ipha->ipha_hdr_checksum = 0;
-					ipha->ipha_hdr_checksum =
-					    (uint16_t)ip_csum_hdr(ipha);
-					flags &= ~HCK_IPV4_HDRCKSUM;
-					flags |= HCK_IPV4_HDRCKSUM_OK;
-				}
-			} else if (sap == ETHERTYPE_IPV6) {
 				/*
-				 * IPv6 header.
+				 * The checksum value stored in the packet needs
+				 * to be correct. Compute it here.
 				 */
-				ip6_t *ip6ha;
+				*up = 0;
+				cksum += (((proto) == IPPROTO_UDP) ?
+				    IP_UDP_CSUM_COMP : IP_TCP_CSUM_COMP);
+				cksum = IP_CSUM(mp, IP_SIMPLE_HDR_LENGTH +
+				    offset, cksum);
+				*(up) = (uint16_t)(cksum ? cksum : ~cksum);
 
-				ASSERT(MBLKL(mp) >= offset + sizeof (ip6_t));
-				/* LINTED: improper alignment cast */
-				ip6ha = (ip6_t *)(mp->b_rptr + offset);
+				/*
+				 * Flag the packet so that it appears
+				 * that the checksum has already been
+				 * verified by the hardware.
+				 */
+				flags &= ~HCK_FULLCKSUM;
+				flags |= HCK_FULLCKSUM_OK;
+				value = 0;
+			}
+
+			if (flags & HCK_IPV4_HDRCKSUM) {
+				ASSERT(ipha != NULL);
+				ipha->ipha_hdr_checksum =
+				    (uint16_t)ip_csum_hdr(ipha);
+				flags &= ~HCK_IPV4_HDRCKSUM;
+				flags |= HCK_IPV4_HDRCKSUM_OK;
 
-				if (flags & HCK_FULLCKSUM) {
-					mac_ipv6_chksum(mp, offset, ip6ha);
-					/*
-					 * Flag the packet so that it appears
-					 * that the checksum has already been
-					 * verified by the hardware.
-					 */
-					flags &= ~HCK_FULLCKSUM;
-					flags |= HCK_FULLCKSUM_OK;
-					value = 0;
-				}
-			} else {
-				continue;
 			}
 		}
 
@@ -409,13 +284,6 @@ mac_fix_cksum(mblk_t *mp_chain)
 				mp = new_mp;
 			}
 
-			/*
-			 * Note: this code properly handles a partial checksum
-			 * for either IPv4 or IPv6. The "stuff", "start" and
-			 * "end" returned from mac_hcksum_get() is correct for
-			 * both protocols.
-			 */
-
 			ipp = mp->b_rptr + offset;
 			/* LINTED: cast may result in improper alignment */
 			up = (uint16_t *)((uchar_t *)ipp + stuff);
diff --git a/usr/src/uts/common/os/ip_cksum.c b/usr/src/uts/common/os/ip_cksum.c
index ab5bf4f5ee..1fa1c9425b 100644
--- a/usr/src/uts/common/os/ip_cksum.c
+++ b/usr/src/uts/common/os/ip_cksum.c
@@ -21,7 +21,6 @@
 /*
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
- * Copyright 2018 Joyent, Inc.
  */
 /* Copyright (c) 1990 Mentat Inc. */
 
@@ -35,7 +34,6 @@
 #include <sys/vtrace.h>
 #include <inet/sctp_crc32.h>
 #include <inet/ip.h>
-#include <inet/ip6.h>
 
 #include <sys/multidata.h>
 #include <sys/multidata_impl.h>
@@ -383,112 +381,6 @@ done:
 	return (sum);
 }
 
-/*
- * Try to determine where and what are the IPv6 header length and
- * pointer to nexthdr value for the upper layer protocol (or an
- * unknown next hdr).
- *
- * Parameters returns a pointer to the nexthdr value;
- * Must handle malformed packets of various sorts.
- * Function returns failure for malformed cases.
- */
-boolean_t
-ip_hdr_length_nexthdr_v6(mblk_t *mp, ip6_t *ip6h, uint16_t *hdr_length_ptr,
-    uint8_t **nexthdrpp)
-{
-	uint16_t length;
-	uint_t	ehdrlen;
-	uint8_t	*nexthdrp;
-	uint8_t *whereptr;
-	uint8_t *endptr;
-	ip6_dest_t *desthdr;
-	ip6_rthdr_t *rthdr;
-	ip6_frag_t *fraghdr;
-
-	ASSERT(IPH_HDR_VERSION(ip6h) == IPV6_VERSION);
-	length = IPV6_HDR_LEN;
-	whereptr = ((uint8_t *)&ip6h[1]); /* point to next hdr */
-	endptr = mp->b_wptr;
-
-	nexthdrp = &ip6h->ip6_nxt;
-	while (whereptr < endptr) {
-		/* Is there enough left for len + nexthdr? */
-		if (whereptr + MIN_EHDR_LEN > endptr)
-			break;
-
-		switch (*nexthdrp) {
-		case IPPROTO_HOPOPTS:
-		case IPPROTO_DSTOPTS:
-			/* Assumes the headers are identical for hbh and dst */
-			desthdr = (ip6_dest_t *)whereptr;
-			ehdrlen = 8 * (desthdr->ip6d_len + 1);
-			if ((uchar_t *)desthdr +  ehdrlen > endptr)
-				return (B_FALSE);
-			nexthdrp = &desthdr->ip6d_nxt;
-			break;
-		case IPPROTO_ROUTING:
-			rthdr = (ip6_rthdr_t *)whereptr;
-			ehdrlen =  8 * (rthdr->ip6r_len + 1);
-			if ((uchar_t *)rthdr +  ehdrlen > endptr)
-				return (B_FALSE);
-			nexthdrp = &rthdr->ip6r_nxt;
-			break;
-		case IPPROTO_FRAGMENT:
-			fraghdr = (ip6_frag_t *)whereptr;
-			ehdrlen = sizeof (ip6_frag_t);
-			if ((uchar_t *)&fraghdr[1] > endptr)
-				return (B_FALSE);
-			nexthdrp = &fraghdr->ip6f_nxt;
-			break;
-		case IPPROTO_NONE:
-			/* No next header means we're finished */
-		default:
-			*hdr_length_ptr = length;
-			*nexthdrpp = nexthdrp;
-			return (B_TRUE);
-		}
-		length += ehdrlen;
-		whereptr += ehdrlen;
-		*hdr_length_ptr = length;
-		*nexthdrpp = nexthdrp;
-	}
-	switch (*nexthdrp) {
-	case IPPROTO_HOPOPTS:
-	case IPPROTO_DSTOPTS:
-	case IPPROTO_ROUTING:
-	case IPPROTO_FRAGMENT:
-		/*
-		 * If any know extension headers are still to be processed,
-		 * the packet's malformed (or at least all the IP header(s) are
-		 * not in the same mblk - and that should never happen.
-		 */
-		return (B_FALSE);
-
-	default:
-		/*
-		 * If we get here, we know that all of the IP headers were in
-		 * the same mblk, even if the ULP header is in the next mblk.
-		 */
-		*hdr_length_ptr = length;
-		*nexthdrpp = nexthdrp;
-		return (B_TRUE);
-	}
-}
-
-/*
- * Return the length of the IPv6 related headers (including extension headers)
- * Returns a length even if the packet is malformed.
- */
-int
-ip_hdr_length_v6(mblk_t *mp, ip6_t *ip6h)
-{
-	uint16_t hdr_len;
-	uint8_t	*nexthdrp;
-
-	(void) ip_hdr_length_nexthdr_v6(mp, ip6h, &hdr_len, &nexthdrp);
-	return (hdr_len);
-}
-
 uint32_t
 sctp_cksum(mblk_t *mp, int offset)
 {
diff --git a/usr/src/uts/common/sys/stream.h b/usr/src/uts/common/sys/stream.h
index 72c561a8f9..a45030ff7e 100644
--- a/usr/src/uts/common/sys/stream.h
+++ b/usr/src/uts/common/sys/stream.h
@@ -21,7 +21,7 @@
 /*
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
- * Copyright 2018 Joyent, Inc.  All rights reserved.
+ * Copyright 2015 Joyent, Inc.  All rights reserved.
  */
 
 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
@@ -338,8 +338,7 @@ typedef struct datab {
 				uint16_t u16;
 			} cksum_val;    /* used to store calculated cksum */
 			uint16_t flags;
-			uint16_t pad;	/* not padding, see DB_LSOMSS, DB_TCI */
-			uint32_t ocsum;	/* original cksum field value */
+			uint16_t pad;
 		} cksum;
 		/*
 		 * Union used for future extensions (pointer to data ?).
diff --git a/usr/src/uts/common/sys/strsubr.h b/usr/src/uts/common/sys/strsubr.h
index 6e1baa9ef2..0f29dd3675 100644
--- a/usr/src/uts/common/sys/strsubr.h
+++ b/usr/src/uts/common/sys/strsubr.h
@@ -1341,7 +1341,6 @@ extern int SAMESTR(queue_t *);
 #define	DB_CKSUMEND(mp)		((mp)->b_datap->db_cksumend)
 #define	DB_CKSUMSTUFF(mp)	((mp)->b_datap->db_cksumstuff)
 #define	DB_CKSUMFLAGS(mp)	((mp)->b_datap->db_struioun.cksum.flags)
-#define	DB_CKSUMOCSUM(mp)	((mp)->b_datap->db_struioun.cksum.ocsum)
 #define	DB_CKSUM16(mp)		((mp)->b_datap->db_cksum16)
 #define	DB_CKSUM32(mp)		((mp)->b_datap->db_cksum32)
 #define	DB_LSOFLAGS(mp)		((mp)->b_datap->db_struioun.cksum.flags)