diff --git a/print-pim.c b/print-pim.c
index 15f4c51..2552595 100644
--- a/print-pim.c
+++ b/print-pim.c
@@ -19,18 +19,21 @@
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#define NETDISSECT_REWORKED
+/* \summary: Protocol Independent Multicast (PIM) printer */
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <tcpdump-stdinc.h>
+#include <netdissect-stdinc.h>
 
-#include "interface.h"
+#include "netdissect.h"
 #include "addrtoname.h"
 #include "extract.h"
 
 #include "ip.h"
+#include "ip6.h"
+#include "ipproto.h"
 
 #define PIMV1_TYPE_QUERY           0
 #define PIMV1_TYPE_REGISTER        1
@@ -134,7 +137,7 @@
 	u_short	pim_cksum;	/* IP style check sum */
 };
 
-static void pimv2_print(netdissect_options *, register const u_char *bp, register u_int len, u_int cksum);
+static void pimv2_print(netdissect_options *, register const u_char *bp, register u_int len, const u_char *);
 
 static void
 pimv1_join_prune_print(netdissect_options *ndo,
@@ -152,7 +155,7 @@
 		hold = EXTRACT_16BITS(&bp[6]);
 		if (hold != 180) {
 			ND_PRINT((ndo, "Hold "));
-			relts_print(ndo, hold);
+			unsigned_relts_print(ndo, hold);
 		}
 		ND_PRINT((ndo, "%s (%s/%d, %s", njoin ? "Join" : "Prune",
 		ipaddr_string(ndo, &bp[26]), bp[25] & 0x3f,
@@ -174,7 +177,7 @@
 	if (ndo->ndo_vflag > 1)
 		ND_PRINT((ndo, "\n"));
 	ND_PRINT((ndo, " Hold time: "));
-	relts_print(ndo, EXTRACT_16BITS(&bp[6]));
+	unsigned_relts_print(ndo, EXTRACT_16BITS(&bp[6]));
 	if (ndo->ndo_vflag < 2)
 		return;
 	bp += 8;
@@ -259,7 +262,7 @@
 		if (ndo->ndo_vflag) {
 			ND_TCHECK2(bp[10],2);
 			ND_PRINT((ndo, " (Hold-time "));
-			relts_print(ndo, EXTRACT_16BITS(&bp[10]));
+			unsigned_relts_print(ndo, EXTRACT_16BITS(&bp[10]));
 			ND_PRINT((ndo, ")"));
 		}
 		break;
@@ -281,7 +284,7 @@
 			if (EXTRACT_32BITS(&bp[12]) != 0xffffffff)
 				ND_PRINT((ndo, "/%s", ipaddr_string(ndo, &bp[12])));
 			ND_PRINT((ndo, " RP %s hold ", ipaddr_string(ndo, &bp[16])));
-			relts_print(ndo, EXTRACT_16BITS(&bp[22]));
+			unsigned_relts_print(ndo, EXTRACT_16BITS(&bp[22]));
 		}
 		break;
 	case PIMV1_TYPE_ASSERT:
@@ -348,7 +351,7 @@
 	ND_PRINT((ndo, " Hold "));
 	hold = EXTRACT_16BITS(&bp[2]);
 	if (hold)
-		relts_print(ndo, EXTRACT_16BITS(&bp[2]));
+		unsigned_relts_print(ndo, EXTRACT_16BITS(&bp[2]));
 	else
 		ND_PRINT((ndo, "FOREVER"));
 
@@ -415,10 +418,10 @@
 
 void
 pim_print(netdissect_options *ndo,
-          register const u_char *bp, register u_int len, u_int cksum)
+          register const u_char *bp, register u_int len, const u_char *bp2)
 {
 	register const u_char *ep;
-	register struct pim *pim = (struct pim *)bp;
+	register const struct pim *pim = (const struct pim *)bp;
 
 	ep = (const u_char *)ndo->ndo_snapend;
 	if (bp >= ep)
@@ -440,7 +443,7 @@
 			          PIM_VER(pim->pim_typever),
 			          len,
 			          tok2str(pimv2_type_values,"Unknown Type",PIM_TYPE(pim->pim_typever))));
-			pimv2_print(ndo, bp, len, cksum);
+			pimv2_print(ndo, bp, len, bp2);
 		}
 		break;
 	default:
@@ -534,12 +537,10 @@
 			af = AF_INET;
 			len = sizeof(struct in_addr);
 			break;
-#ifdef INET6
 		case 2:
 			af = AF_INET6;
 			len = sizeof(struct in6_addr);
 			break;
-#endif
 		default:
 			return -1;
 		}
@@ -551,11 +552,9 @@
 		case sizeof(struct in_addr):
 			af = AF_INET;
 			break;
-#ifdef INET6
 		case sizeof(struct in6_addr):
 			af = AF_INET6;
 			break;
-#endif
 		default:
 			return -1;
 			break;
@@ -572,12 +571,10 @@
 			if (!silent)
 				ND_PRINT((ndo, "%s", ipaddr_string(ndo, bp)));
 		}
-#ifdef INET6
 		else if (af == AF_INET6) {
 			if (!silent)
 				ND_PRINT((ndo, "%s", ip6addr_string(ndo, bp)));
 		}
-#endif
 		return hdrlen + len;
 	case pimv2_group:
 	case pimv2_source:
@@ -589,7 +586,6 @@
 					ND_PRINT((ndo, "/%u", bp[1]));
 			}
 		}
-#ifdef INET6
 		else if (af == AF_INET6) {
 			if (!silent) {
 				ND_PRINT((ndo, "%s", ip6addr_string(ndo, bp + 2)));
@@ -597,7 +593,6 @@
 					ND_PRINT((ndo, "/%u", bp[1]));
 			}
 		}
-#endif
 		if (bp[0] && !silent) {
 			if (at == pimv2_group) {
 				ND_PRINT((ndo, "(0x%02x)", bp[0]));
@@ -620,13 +615,50 @@
 	return -1;
 }
 
+enum checksum_status {
+	CORRECT,
+	INCORRECT,
+	UNVERIFIED
+};
+
+static enum checksum_status
+pimv2_check_checksum(netdissect_options *ndo, const u_char *bp,
+		     const u_char *bp2, u_int len)
+{
+	const struct ip *ip;
+	u_int cksum;
+
+	if (!ND_TTEST2(bp[0], len)) {
+		/* We don't have all the data. */
+		return (UNVERIFIED);
+	}
+	ip = (const struct ip *)bp2;
+	if (IP_V(ip) == 4) {
+		struct cksum_vec vec[1];
+
+		vec[0].ptr = bp;
+		vec[0].len = len;
+		cksum = in_cksum(vec, 1);
+		return (cksum ? INCORRECT : CORRECT);
+	} else if (IP_V(ip) == 6) {
+		const struct ip6_hdr *ip6;
+
+		ip6 = (const struct ip6_hdr *)bp2;
+		cksum = nextproto6_cksum(ndo, ip6, bp, len, len, IPPROTO_PIM);
+		return (cksum ? INCORRECT : CORRECT);
+	} else {
+		return (UNVERIFIED);
+	}
+}
+
 static void
 pimv2_print(netdissect_options *ndo,
-            register const u_char *bp, register u_int len, u_int cksum)
+            register const u_char *bp, register u_int len, const u_char *bp2)
 {
 	register const u_char *ep;
-	register struct pim *pim = (struct pim *)bp;
+	register const struct pim *pim = (const struct pim *)bp;
 	int advance;
+	enum checksum_status cksum_status;
 
 	ep = (const u_char *)ndo->ndo_snapend;
 	if (bp >= ep)
@@ -642,7 +674,41 @@
 	if (EXTRACT_16BITS(&pim->pim_cksum) == 0) {
 		ND_PRINT((ndo, "(unverified)"));
 	} else {
-		ND_PRINT((ndo, "(%scorrect)", ND_TTEST2(bp[0], len) && cksum ? "in" : "" ));
+		if (PIM_TYPE(pim->pim_typever) == PIMV2_TYPE_REGISTER) {
+			/*
+			 * The checksum only covers the packet header,
+			 * not the encapsulated packet.
+			 */
+			cksum_status = pimv2_check_checksum(ndo, bp, bp2, 8);
+			if (cksum_status == INCORRECT) {
+				/*
+				 * To quote RFC 4601, "For interoperability
+				 * reasons, a message carrying a checksum
+				 * calculated over the entire PIM Register
+				 * message should also be accepted."
+				 */
+				cksum_status = pimv2_check_checksum(ndo, bp, bp2, len);
+			}
+		} else {
+			/*
+			 * The checksum covers the entire packet.
+			 */
+			cksum_status = pimv2_check_checksum(ndo, bp, bp2, len);
+		}
+		switch (cksum_status) {
+
+		case CORRECT:
+			ND_PRINT((ndo, "(correct)"));
+			break;
+
+		case INCORRECT:
+			ND_PRINT((ndo, "(incorrect)"));
+			break;
+
+		case UNVERIFIED:
+			ND_PRINT((ndo, "(unverified)"));
+			break;
+		}
 	}
 
 	switch (PIM_TYPE(pim->pim_typever)) {
@@ -663,7 +729,7 @@
 
 			switch (otype) {
 			case PIMV2_HELLO_OPTION_HOLDTIME:
-				relts_print(ndo, EXTRACT_16BITS(bp));
+				unsigned_relts_print(ndo, EXTRACT_16BITS(bp));
 				break;
 
 			case PIMV2_HELLO_OPTION_LANPRUNEDELAY:
@@ -704,7 +770,7 @@
 				ND_PRINT((ndo, "v%d", *bp));
 				if (*(bp+1) != 0) {
 					ND_PRINT((ndo, ", interval "));
-					relts_print(ndo, *(bp+1));
+					unsigned_relts_print(ndo, *(bp+1));
 				}
 				if (EXTRACT_16BITS(bp+2) != 0) {
 					ND_PRINT((ndo, " ?0x%04x?", EXTRACT_16BITS(bp+2)));
@@ -719,8 +785,6 @@
 				if (ndo->ndo_vflag > 1) {
 					const u_char *ptr = bp;
 					while (ptr < (bp+olen)) {
-						int advance;
-
 						ND_PRINT((ndo, "\n\t    "));
 						advance = pimv2_addr_print(ndo, ptr, pimv2_unicast, 0);
 						if (advance < 0) {
@@ -746,7 +810,7 @@
 
 	case PIMV2_TYPE_REGISTER:
 	{
-		struct ip *ip;
+		const struct ip *ip;
 
 		ND_TCHECK2(*(bp + 4), PIMV2_REGISTER_FLAG_LEN);
 
@@ -757,7 +821,7 @@
 
 		bp += 8; len -= 8;
 		/* encapsulated multicast packet */
-		ip = (struct ip *)bp;
+		ip = (const struct ip *)bp;
 		switch (IP_V(ip)) {
                 case 0: /* Null header */
 			ND_PRINT((ndo, "IP-Null-header %s > %s",
@@ -868,7 +932,7 @@
 			if (holdtime == 0xffff)
 				ND_PRINT((ndo, "infinite"));
 			else
-				relts_print(ndo, holdtime);
+				unsigned_relts_print(ndo, holdtime);
 		}
 		bp += 4; len -= 4;
 		for (i = 0; i < ngroup; i++) {
@@ -972,7 +1036,7 @@
 					goto bs_done;
 				}
 				ND_PRINT((ndo, ",holdtime="));
-				relts_print(ndo, EXTRACT_16BITS(bp));
+				unsigned_relts_print(ndo, EXTRACT_16BITS(bp));
 				if (bp + 2 >= ep) {
 					ND_PRINT((ndo, "...)"));
 					goto bs_done;
@@ -1024,7 +1088,7 @@
 		ND_PRINT((ndo, " prio=%d", bp[1]));
 		if (bp + 3 >= ep) break;
 		ND_PRINT((ndo, " holdtime="));
-		relts_print(ndo, EXTRACT_16BITS(&bp[2]));
+		unsigned_relts_print(ndo, EXTRACT_16BITS(&bp[2]));
 		bp += 4;
 
 		/* Encoded-Unicast-RP-Address */
@@ -1070,7 +1134,7 @@
 		bp += advance;
 		ND_TCHECK2(bp[0], 2);
 		ND_PRINT((ndo, " TUNR "));
-		relts_print(ndo, EXTRACT_16BITS(bp));
+		unsigned_relts_print(ndo, EXTRACT_16BITS(bp));
 		break;