]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-ip.c
Fix the pointer tests in the non-ndoified TTEST2() macro as well.
[tcpdump] / print-ip.c
index 0529fa5be3cc629816c57d0fed92b3ac079458f0..362465e698defc7804718061be1acbb7d494c54e 100644 (file)
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef lint
-static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.156 2007-01-17 14:07:36 hannes Exp $ (LBL)";
-#endif
-
+#define NETDISSECT_REWORKED
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
 #include <tcpdump-stdinc.h>
 
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
-#include "addrtoname.h"
 #include "interface.h"
+#include "addrtoname.h"
 #include "extract.h"                   /* must come after interface.h */
 
 #include "ip.h"
 #include "ipproto.h"
 
-struct tok ip_option_values[] = {
+static const char tstr[] = "[|ip]";
+
+static const struct tok ip_option_values[] = {
     { IPOPT_EOL, "EOL" },
     { IPOPT_NOP, "NOP" },
     { IPOPT_TS, "timestamp" },
@@ -50,6 +46,7 @@ struct tok ip_option_values[] = {
     { IPOPT_SSRR, "SSRR" },
     { IPOPT_LSRR, "LSRR" },
     { IPOPT_RA, "RA" },
+    { IPOPT_RFC1393, "traceroute" },
     { 0, NULL }
 };
 
@@ -57,25 +54,26 @@ struct tok ip_option_values[] = {
  * print the recorded route in an IP RR, LSRR or SSRR option.
  */
 static void
-ip_printroute(register const u_char *cp, u_int length)
+ip_printroute(netdissect_options *ndo,
+              register const u_char *cp, u_int length)
 {
        register u_int ptr;
        register u_int len;
 
        if (length < 3) {
-               printf(" [bad length %u]", length);
+               ND_PRINT((ndo, " [bad length %u]", length));
                return;
        }
        if ((length + 1) & 3)
-               printf(" [bad length %u]", length);
+               ND_PRINT((ndo, " [bad length %u]", length));
        ptr = cp[2] - 1;
        if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
-               printf(" [bad ptr %u]", cp[2]);
+               ND_PRINT((ndo, " [bad ptr %u]", cp[2]));
 
        for (len = 3; len < length; len += 4) {
-               printf(" %s", ipaddr_string(&cp[len]));
-                if (ptr > len)
-                        printf(",");
+               ND_PRINT((ndo, " %s", ipaddr_string(ndo, &cp[len])));
+               if (ptr > len)
+                       ND_PRINT((ndo, ","));
        }
 }
 
@@ -86,13 +84,14 @@ ip_printroute(register const u_char *cp, u_int length)
  * This is used for UDP and TCP pseudo-header in the checksum
  * calculation.
  */
-u_int32_t
-ip_finddst(const struct ip *ip)
+static uint32_t
+ip_finddst(netdissect_options *ndo,
+           const struct ip *ip)
 {
        int length;
        int len;
        const u_char *cp;
-       u_int32_t retval;
+       uint32_t retval;
 
        cp = (const u_char *)(ip + 1);
        length = (IP_HL(ip) << 2) - sizeof(struct ip);
@@ -100,36 +99,71 @@ ip_finddst(const struct ip *ip)
        for (; length > 0; cp += len, length -= len) {
                int tt;
 
-               TCHECK(*cp);
+               ND_TCHECK(*cp);
                tt = *cp;
                if (tt == IPOPT_EOL)
                        break;
                else if (tt == IPOPT_NOP)
                        len = 1;
                else {
-                       TCHECK(cp[1]);
+                       ND_TCHECK(cp[1]);
                        len = cp[1];
                        if (len < 2)
                                break;
                }
-               TCHECK2(*cp, len);
+               ND_TCHECK2(*cp, len);
                switch (tt) {
 
                case IPOPT_SSRR:
                case IPOPT_LSRR:
                        if (len < 7)
                                break;
-                       memcpy(&retval, cp + len - 4, 4);
+                       UNALIGNED_MEMCPY(&retval, cp + len - 4, 4);
                        return retval;
                }
        }
 trunc:
-       memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
+       UNALIGNED_MEMCPY(&retval, &ip->ip_dst.s_addr, sizeof(uint32_t));
        return retval;
 }
 
+/*
+ * Compute a V4-style checksum by building a pseudoheader.
+ */
+int
+nextproto4_cksum(netdissect_options *ndo,
+                 const struct ip *ip, const uint8_t *data,
+                 u_int len, u_int covlen, u_int next_proto)
+{
+       struct phdr {
+               uint32_t src;
+               uint32_t dst;
+               u_char mbz;
+               u_char proto;
+               uint16_t len;
+       } ph;
+       struct cksum_vec vec[2];
+
+       /* pseudo-header.. */
+       ph.len = htons((uint16_t)len);
+       ph.mbz = 0;
+       ph.proto = next_proto;
+       UNALIGNED_MEMCPY(&ph.src, &ip->ip_src.s_addr, sizeof(uint32_t));
+       if (IP_HL(ip) == 5)
+               UNALIGNED_MEMCPY(&ph.dst, &ip->ip_dst.s_addr, sizeof(uint32_t));
+       else
+               ph.dst = ip_finddst(ndo, ip);
+
+       vec[0].ptr = (const uint8_t *)(void *)&ph;
+       vec[0].len = sizeof(ph);
+       vec[1].ptr = data;
+       vec[1].len = covlen;
+       return (in_cksum(vec, 2));
+}
+
 static void
-ip_printts(register const u_char *cp, u_int length)
+ip_printts(netdissect_options *ndo,
+           register const u_char *cp, u_int length)
 {
        register u_int ptr;
        register u_int len;
@@ -137,23 +171,23 @@ ip_printts(register const u_char *cp, u_int length)
        const char *type;
 
        if (length < 4) {
-               printf("[bad length %u]", length);
+               ND_PRINT((ndo, "[bad length %u]", length));
                return;
        }
-       printf(" TS{");
+       ND_PRINT((ndo, " TS{"));
        hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
        if ((length - 4) & (hoplen-1))
-               printf("[bad length %u]", length);
+               ND_PRINT((ndo, "[bad length %u]", length));
        ptr = cp[2] - 1;
        len = 0;
        if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
-               printf("[bad ptr %u]", cp[2]);
+               ND_PRINT((ndo, "[bad ptr %u]", cp[2]));
        switch (cp[3]&0xF) {
        case IPOPT_TS_TSONLY:
-               printf("TSONLY");
+               ND_PRINT((ndo, "TSONLY"));
                break;
        case IPOPT_TS_TSANDADDR:
-               printf("TS+ADDR");
+               ND_PRINT((ndo, "TS+ADDR"));
                break;
        /*
         * prespecified should really be 3, but some ones might send 2
@@ -162,13 +196,13 @@ ip_printts(register const u_char *cp, u_int length)
         */
 
        case 2:
-               printf("PRESPEC2.0");
+               ND_PRINT((ndo, "PRESPEC2.0"));
                break;
        case 3:                 /* IPOPT_TS_PRESPEC */
-               printf("PRESPEC");
+               ND_PRINT((ndo, "PRESPEC"));
                break;
        default:
-               printf("[bad ts type %d]", cp[3]&0xF);
+               ND_PRINT((ndo, "[bad ts type %d]", cp[3]&0xF));
                goto done;
        }
 
@@ -176,25 +210,26 @@ ip_printts(register const u_char *cp, u_int length)
        for (len = 4; len < length; len += hoplen) {
                if (ptr == len)
                        type = " ^ ";
-               printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
-                      hoplen!=8 ? "" : ipaddr_string(&cp[len]));
+               ND_PRINT((ndo, "%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
+                      hoplen!=8 ? "" : ipaddr_string(ndo, &cp[len])));
                type = " ";
        }
 
 done:
-       printf("%s", ptr == len ? " ^ " : "");
+       ND_PRINT((ndo, "%s", ptr == len ? " ^ " : ""));
 
        if (cp[3]>>4)
-               printf(" [%d hops not recorded]} ", cp[3]>>4);
+               ND_PRINT((ndo, " [%d hops not recorded]} ", cp[3]>>4));
        else
-               printf("}");
+               ND_PRINT((ndo, "}"));
 }
 
 /*
  * print IP options.
  */
 static void
-ip_optprint(register const u_char *cp, u_int length)
+ip_optprint(netdissect_options *ndo,
+            register const u_char *cp, u_int length)
 {
        register u_int option_len;
        const char *sep = "";
@@ -202,57 +237,57 @@ ip_optprint(register const u_char *cp, u_int length)
        for (; length > 0; cp += option_len, length -= option_len) {
                u_int option_code;
 
-               printf("%s", sep);
+               ND_PRINT((ndo, "%s", sep));
                sep = ",";
 
-               TCHECK(*cp);
+               ND_TCHECK(*cp);
                option_code = *cp;
 
-                printf("%s",
-                        tok2str(ip_option_values,"unknown %u",option_code));
+               ND_PRINT((ndo, "%s",
+                         tok2str(ip_option_values,"unknown %u",option_code)));
 
                if (option_code == IPOPT_NOP ||
                     option_code == IPOPT_EOL)
                        option_len = 1;
 
                else {
-                       TCHECK(cp[1]);
+                       ND_TCHECK(cp[1]);
                        option_len = cp[1];
                        if (option_len < 2) {
-                               printf(" [bad length %u]", option_len);
+                               ND_PRINT((ndo, " [bad length %u]", option_len));
                                return;
                        }
                }
 
                if (option_len > length) {
-                       printf(" [bad length %u]", option_len);
+                       ND_PRINT((ndo, " [bad length %u]", option_len));
                        return;
                }
 
-                TCHECK2(*cp, option_len);
+               ND_TCHECK2(*cp, option_len);
 
                switch (option_code) {
                case IPOPT_EOL:
                        return;
 
                case IPOPT_TS:
-                       ip_printts(cp, option_len);
+                       ip_printts(ndo, cp, option_len);
                        break;
 
                case IPOPT_RR:       /* fall through */
                case IPOPT_SSRR:
                case IPOPT_LSRR:
-                       ip_printroute(cp, option_len);
+                       ip_printroute(ndo, cp, option_len);
                        break;
 
                case IPOPT_RA:
                        if (option_len < 4) {
-                               printf(" [bad length %u]", option_len);
+                               ND_PRINT((ndo, " [bad length %u]", option_len));
                                break;
                        }
-                        TCHECK(cp[3]);
-                        if (EXTRACT_16BITS(&cp[2]) != 0)
-                            printf(" value %u", EXTRACT_16BITS(&cp[2]));
+                       ND_TCHECK(cp[3]);
+                       if (EXTRACT_16BITS(&cp[2]) != 0)
+                               ND_PRINT((ndo, " value %u", EXTRACT_16BITS(&cp[2])));
                        break;
 
                case IPOPT_NOP:       /* nothing to print - fall through */
@@ -264,98 +299,12 @@ ip_optprint(register const u_char *cp, u_int length)
        return;
 
 trunc:
-       printf("[|ip]");
-}
-
-/*
- * compute an IP header checksum.
- * don't modifiy the packet.
- */
-u_short
-in_cksum(const u_short *addr, register u_int len, int csum)
-{
-       int nleft = len;
-       const u_short *w = addr;
-       u_short answer;
-       int sum = csum;
-
-       /*
-        *  Our algorithm is simple, using a 32 bit accumulator (sum),
-        *  we add sequential 16 bit words to it, and at the end, fold
-        *  back all the carry bits from the top 16 bits into the lower
-        *  16 bits.
-        */
-       while (nleft > 1)  {
-               sum += *w++;
-               nleft -= 2;
-       }
-       if (nleft == 1)
-               sum += htons(*(u_char *)w<<8);
-
-       /*
-        * add back carry outs from top 16 bits to low 16 bits
-        */
-       sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
-       sum += (sum >> 16);                     /* add carry */
-       answer = ~sum;                          /* truncate to 16 bits */
-       return (answer);
-}
-
-/*
- * Given the host-byte-order value of the checksum field in a packet
- * header, and the network-byte-order computed checksum of the data
- * that the checksum covers (including the checksum itself), compute
- * what the checksum field *should* have been.
- */
-u_int16_t
-in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
-{
-       u_int32_t shouldbe;
-
-       /*
-        * The value that should have gone into the checksum field
-        * is the negative of the value gotten by summing up everything
-        * *but* the checksum field.
-        *
-        * We can compute that by subtracting the value of the checksum
-        * field from the sum of all the data in the packet, and then
-        * computing the negative of that value.
-        *
-        * "sum" is the value of the checksum field, and "computed_sum"
-        * is the negative of the sum of all the data in the packets,
-        * so that's -(-computed_sum - sum), or (sum + computed_sum).
-        *
-        * All the arithmetic in question is one's complement, so the
-        * addition must include an end-around carry; we do this by
-        * doing the arithmetic in 32 bits (with no sign-extension),
-        * and then adding the upper 16 bits of the sum, which contain
-        * the carry, to the lower 16 bits of the sum, and then do it
-        * again in case *that* sum produced a carry.
-        *
-        * As RFC 1071 notes, the checksum can be computed without
-        * byte-swapping the 16-bit words; summing 16-bit words
-        * on a big-endian machine gives a big-endian checksum, which
-        * can be directly stuffed into the big-endian checksum fields
-        * in protocol headers, and summing words on a little-endian
-        * machine gives a little-endian checksum, which must be
-        * byte-swapped before being stuffed into a big-endian checksum
-        * field.
-        *
-        * "computed_sum" is a network-byte-order value, so we must put
-        * it in host byte order before subtracting it from the
-        * host-byte-order value from the header; the adjusted checksum
-        * will be in host byte order, which is what we'll return.
-        */
-       shouldbe = sum;
-       shouldbe += ntohs(computed_sum);
-       shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
-       shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
-       return shouldbe;
+       ND_PRINT((ndo, "%s", tstr));
 }
 
 #define IP_RES 0x8000
 
-static struct tok ip_frag_values[] = {
+static const struct tok ip_frag_values[] = {
         { IP_MF,        "+" },
         { IP_DF,        "DF" },
        { IP_RES,       "rsvd" }, /* The RFC3514 evil ;-) bit */
@@ -375,13 +324,14 @@ ip_print_demux(netdissect_options *ndo,
               struct ip_print_demux_state *ipds)
 {
        struct protoent *proto;
+       struct cksum_vec vec[1];
 
 again:
        switch (ipds->nh) {
 
        case IPPROTO_AH:
                ipds->nh = *ipds->cp;
-               ipds->advance = ah_print(ipds->cp);
+               ipds->advance = ah_print(ndo, ipds->cp);
                if (ipds->advance <= 0)
                        break;
                ipds->cp += ipds->advance;
@@ -401,11 +351,11 @@ again:
                ipds->nh = enh & 0xff;
                goto again;
        }
-       
+
        case IPPROTO_IPCOMP:
        {
                int enh;
-               ipds->advance = ipcomp_print(ipds->cp, &enh);
+               ipds->advance = ipcomp_print(ndo, ipds->cp, &enh);
                if (ipds->advance <= 0)
                        break;
                ipds->cp += ipds->advance;
@@ -415,31 +365,31 @@ again:
        }
 
        case IPPROTO_SCTP:
-               sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
+               sctp_print(ndo, ipds->cp, (const u_char *)ipds->ip, ipds->len);
                break;
 
        case IPPROTO_DCCP:
-               dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
+               dccp_print(ndo, ipds->cp, (const u_char *)ipds->ip, ipds->len);
                break;
-               
+
        case IPPROTO_TCP:
                /* pass on the MF bit plus the offset to detect fragments */
-               tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
+               tcp_print(ndo, ipds->cp, ipds->len, (const u_char *)ipds->ip,
                          ipds->off & (IP_MF|IP_OFFMASK));
                break;
-               
+
        case IPPROTO_UDP:
                /* pass on the MF bit plus the offset to detect fragments */
-               udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
+               udp_print(ndo, ipds->cp, ipds->len, (const u_char *)ipds->ip,
                          ipds->off & (IP_MF|IP_OFFMASK));
                break;
-               
+
        case IPPROTO_ICMP:
                /* pass on the MF bit plus the offset to detect fragments */
-               icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
+               icmp_print(ndo, ipds->cp, ipds->len, (const u_char *)ipds->ip,
                           ipds->off & (IP_MF|IP_OFFMASK));
                break;
-               
+
        case IPPROTO_PIGP:
                /*
                 * XXX - the current IANA protocol number assignments
@@ -454,72 +404,87 @@ again:
                 * match was the current protocol number
                 * assignments say.
                 */
-               igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
+               igrp_print(ndo, ipds->cp, ipds->len);
                break;
-               
+
        case IPPROTO_EIGRP:
-               eigrp_print(ipds->cp, ipds->len);
+               eigrp_print(ndo, ipds->cp, ipds->len);
                break;
-               
+
        case IPPROTO_ND:
                ND_PRINT((ndo, " nd %d", ipds->len));
                break;
 
        case IPPROTO_EGP:
-               egp_print(ipds->cp, ipds->len);
+               egp_print(ndo, ipds->cp, ipds->len);
                break;
 
        case IPPROTO_OSPF:
-               ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
+               ospf_print(ndo, ipds->cp, ipds->len, (const u_char *)ipds->ip);
                break;
 
        case IPPROTO_IGMP:
-               igmp_print(ipds->cp, ipds->len);
+               igmp_print(ndo, ipds->cp, ipds->len);
                break;
 
        case IPPROTO_IPV4:
                /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
-               ip_print(gndo, ipds->cp, ipds->len);
-               if (! vflag) {
+               ip_print(ndo, ipds->cp, ipds->len);
+               if (! ndo->ndo_vflag) {
                        ND_PRINT((ndo, " (ipip-proto-4)"));
                        return;
                }
                break;
-               
+
 #ifdef INET6
        case IPPROTO_IPV6:
                /* ip6-in-ip encapsulation */
-               ip6_print(ipds->cp, ipds->len);
+               ip6_print(ndo, ipds->cp, ipds->len);
                break;
 #endif /*INET6*/
 
        case IPPROTO_RSVP:
-               rsvp_print(ipds->cp, ipds->len);
+               rsvp_print(ndo, ipds->cp, ipds->len);
                break;
 
        case IPPROTO_GRE:
                /* do it */
-               gre_print(ipds->cp, ipds->len);
+               gre_print(ndo, ipds->cp, ipds->len);
                break;
 
        case IPPROTO_MOBILE:
-               mobile_print(ipds->cp, ipds->len);
+               mobile_print(ndo, ipds->cp, ipds->len);
                break;
 
        case IPPROTO_PIM:
-               pim_print(ipds->cp,  ipds->len);
+               vec[0].ptr = ipds->cp;
+               vec[0].len = ipds->len;
+               pim_print(ndo, ipds->cp, ipds->len, in_cksum(vec, 1));
                break;
 
        case IPPROTO_VRRP:
-               vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
+               if (ndo->ndo_packettype == PT_CARP) {
+                       if (ndo->ndo_vflag)
+                               ND_PRINT((ndo, "carp %s > %s: ",
+                                            ipaddr_string(ndo, &ipds->ip->ip_src),
+                                            ipaddr_string(ndo, &ipds->ip->ip_dst)));
+                       carp_print(ndo, ipds->cp, ipds->len, ipds->ip->ip_ttl);
+               } else {
+                       if (ndo->ndo_vflag)
+                               ND_PRINT((ndo, "vrrp %s > %s: ",
+                                            ipaddr_string(ndo, &ipds->ip->ip_src),
+                                            ipaddr_string(ndo, &ipds->ip->ip_dst)));
+                       vrrp_print(ndo, ipds->cp, ipds->len,
+                               (const u_char *)ipds->ip, ipds->ip->ip_ttl);
+               }
                break;
 
        case IPPROTO_PGM:
-               pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
+               pgm_print(ndo, ipds->cp, ipds->len, (const u_char *)ipds->ip);
                break;
 
        default:
-               if ((proto = getprotobynumber(ipds->nh)) != NULL)
+               if (ndo->ndo_nflag==0 && (proto = getprotobynumber(ipds->nh)) != NULL)
                        ND_PRINT((ndo, " %s", proto->p_name));
                else
                        ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
@@ -527,7 +492,7 @@ again:
                break;
        }
 }
-              
+
 void
 ip_print_inner(netdissect_options *ndo,
               const u_char *bp,
@@ -559,40 +524,41 @@ ip_print(netdissect_options *ndo,
        struct ip_print_demux_state *ipds=&ipd;
        const u_char *ipend;
        u_int hlen;
-       u_int16_t sum, ip_sum;
+       struct cksum_vec vec[1];
+       uint16_t sum, ip_sum;
        struct protoent *proto;
 
        ipds->ip = (const struct ip *)bp;
        if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
-           printf("IP%u ", IP_V(ipds->ip));
+           ND_PRINT((ndo, "IP%u ", IP_V(ipds->ip)));
            if (IP_V(ipds->ip) == 6)
-               printf(", wrong link-layer encapsulation");
+             ND_PRINT((ndo, ", wrong link-layer encapsulation"));
        }
-        else if (!eflag)
-           printf("IP ");
+       else if (!ndo->ndo_eflag)
+               ND_PRINT((ndo, "IP "));
 
-       if ((u_char *)(ipds->ip + 1) > snapend) {
-               printf("[|ip]");
+       if ((u_char *)(ipds->ip + 1) > ndo->ndo_snapend) {
+               ND_PRINT((ndo, "%s", tstr));
                return;
        }
        if (length < sizeof (struct ip)) {
-               (void)printf("truncated-ip %u", length);
+               ND_PRINT((ndo, "truncated-ip %u", length));
                return;
        }
        hlen = IP_HL(ipds->ip) * 4;
        if (hlen < sizeof (struct ip)) {
-               (void)printf("bad-hlen %u", hlen);
+               ND_PRINT((ndo, "bad-hlen %u", hlen));
                return;
        }
 
        ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
        if (length < ipds->len)
-               (void)printf("truncated-ip - %u bytes missing! ",
-                       ipds->len - length);
+               ND_PRINT((ndo, "truncated-ip - %u bytes missing! ",
+                       ipds->len - length));
        if (ipds->len < hlen) {
 #ifdef GUESS_TSO
             if (ipds->len) {
-                (void)printf("bad-len %u", ipds->len);
+                ND_PRINT((ndo, "bad-len %u", ipds->len));
                 return;
             }
             else {
@@ -600,7 +566,7 @@ ip_print(netdissect_options *ndo,
                 ipds->len = length;
             }
 #else
-            (void)printf("bad-len %u", ipds->len);
+            ND_PRINT((ndo, "bad-len %u", ipds->len));
             return;
 #endif /* GUESS_TSO */
        }
@@ -609,31 +575,31 @@ ip_print(netdissect_options *ndo,
         * Cut off the snapshot length to the end of the IP payload.
         */
        ipend = bp + ipds->len;
-       if (ipend < snapend)
-               snapend = ipend;
+       if (ipend < ndo->ndo_snapend)
+               ndo->ndo_snapend = ipend;
 
        ipds->len -= hlen;
 
        ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
 
-        if (vflag) {
-            (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
+        if (ndo->ndo_vflag) {
+            ND_PRINT((ndo, "(tos 0x%x", (int)ipds->ip->ip_tos));
             /* ECN bits */
             if (ipds->ip->ip_tos & 0x03) {
                 switch (ipds->ip->ip_tos & 0x03) {
                 case 1:
-                    (void)printf(",ECT(1)");
+                    ND_PRINT((ndo, ",ECT(1)"));
                     break;
                 case 2:
-                    (void)printf(",ECT(0)");
+                    ND_PRINT((ndo, ",ECT(0)"));
                     break;
                 case 3:
-                    (void)printf(",CE");
+                    ND_PRINT((ndo, ",CE"));
                 }
             }
 
             if (ipds->ip->ip_ttl >= 1)
-                (void)printf(", ttl %3u", ipds->ip->ip_ttl);    
+                ND_PRINT((ndo, ", ttl %u", ipds->ip->ip_ttl));
 
            /*
             * for the firewall guys, print id, offset.
@@ -641,31 +607,33 @@ ip_print(netdissect_options *ndo,
             * For unfragmented datagrams, note the don't fragment flag.
             */
 
-           (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
+           ND_PRINT((ndo, ", id %u, offset %u, flags [%s], proto %s (%u)",
                          EXTRACT_16BITS(&ipds->ip->ip_id),
                          (ipds->off & 0x1fff) * 8,
                          bittok2str(ip_frag_values, "none", ipds->off&0xe000),
                          tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
-                         ipds->ip->ip_p);
+                         ipds->ip->ip_p));
 
-            (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));
+            ND_PRINT((ndo, ", length %u", EXTRACT_16BITS(&ipds->ip->ip_len)));
 
             if ((hlen - sizeof(struct ip)) > 0) {
-                printf(", options (");
-                ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
-                printf(")");
+                ND_PRINT((ndo, ", options ("));
+                ip_optprint(ndo, (u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
+                ND_PRINT((ndo, ")"));
             }
 
-           if ((u_char *)ipds->ip + hlen <= snapend) {
-               sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
+           if (!ndo->ndo_Kflag && (u_char *)ipds->ip + hlen <= ndo->ndo_snapend) {
+               vec[0].ptr = (const uint8_t *)(void *)ipds->ip;
+               vec[0].len = hlen;
+               sum = in_cksum(vec, 1);
                if (sum != 0) {
                    ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
-                   (void)printf(", bad cksum %x (->%x)!", ip_sum,
-                            in_cksum_shouldbe(ip_sum, sum));
+                   ND_PRINT((ndo, ", bad cksum %x (->%x)!", ip_sum,
+                            in_cksum_shouldbe(ip_sum, sum)));
                }
            }
 
-            printf(") ");
+               ND_PRINT((ndo, ")\n    "));
        }
 
        /*
@@ -678,53 +646,52 @@ ip_print(netdissect_options *ndo,
 
                if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
                    ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
-                       (void)printf("%s > %s: ",
-                                    ipaddr_string(&ipds->ip->ip_src),
-                                    ipaddr_string(&ipds->ip->ip_dst));
+                       ND_PRINT((ndo, "%s > %s: ",
+                                    ipaddr_string(ndo, &ipds->ip->ip_src),
+                                    ipaddr_string(ndo, &ipds->ip->ip_dst)));
                }
                ip_print_demux(ndo, ipds);
        } else {
            /* Ultra quiet now means that all this stuff should be suppressed */
-           if (qflag > 1) return;
+           if (ndo->ndo_qflag > 1) return;
 
            /*
             * if this isn't the first frag, we're missing the
             * next level protocol header.  print the ip addr
             * and the protocol.
             */
-           if (ipds->off & 0x1fff) {
-               (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
-                            ipaddr_string(&ipds->ip->ip_dst));
-               if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
-                   (void)printf(" %s", proto->p_name);
-               else
-                   (void)printf(" ip-proto-%d", ipds->ip->ip_p);
-           } 
+               if (ipds->off & 0x1fff) {
+                       ND_PRINT((ndo, "%s > %s:", ipaddr_string(ndo, &ipds->ip->ip_src),
+                                 ipaddr_string(ndo, &ipds->ip->ip_dst)));
+                       if (!ndo->ndo_nflag && (proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
+                               ND_PRINT((ndo, " %s", proto->p_name));
+                       else
+                               ND_PRINT((ndo, " ip-proto-%d", ipds->ip->ip_p));
+               }
        }
 }
 
 void
-ipN_print(register const u_char *bp, register u_int length)
+ipN_print(netdissect_options *ndo, register const u_char *bp, register u_int length)
 {
-       struct ip *ip, hdr;
+       struct ip hdr;
 
-       ip = (struct ip *)bp;
        if (length < 4) {
-               (void)printf("truncated-ip %d", length);
+               ND_PRINT((ndo, "truncated-ip %d", length));
                return;
        }
-       memcpy (&hdr, (char *)ip, 4);
+       memcpy (&hdr, bp, 4);
        switch (IP_V(&hdr)) {
        case 4:
-               ip_print (gndo, bp, length);
+               ip_print (ndo, bp, length);
                return;
 #ifdef INET6
        case 6:
-               ip6_print (bp, length);
+               ip6_print (ndo, bp, length);
                return;
 #endif
        default:
-               (void)printf("unknown ip %d", IP_V(&hdr));
+               ND_PRINT((ndo, "unknown ip %d", IP_V(&hdr)));
                return;
        }
 }