]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-ip.c
More UNALIGNED_MEM{CPY,CMP} on IP addresses.
[tcpdump] / print-ip.c
index 137b2633a3752761fba7437fd1b816fb40ddb828..22bd80054775e055fce7555b4f0d5f27c0c4cfc7 100644 (file)
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef lint
-static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.152 2005-10-07 10:48:14 hannes Exp $ (LBL)";
-#endif
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -41,7 +36,9 @@ static const char rcsid[] _U_ =
 #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 +47,7 @@ struct tok ip_option_values[] = {
     { IPOPT_SSRR, "SSRR" },
     { IPOPT_LSRR, "LSRR" },
     { IPOPT_RA, "RA" },
+    { IPOPT_RFC1393, "traceroute" },
     { 0, NULL }
 };
 
@@ -73,9 +71,9 @@ ip_printroute(register const u_char *cp, u_int length)
                printf(" [bad ptr %u]", cp[2]);
 
        for (len = 3; len < length; len += 4) {
-               printf("%s", ipaddr_string(&cp[len]));
+               printf(" %s", ipaddr_string(&cp[len]));
                 if (ptr > len)
-                    printf (", ");
+                        printf(",");
        }
 }
 
@@ -86,7 +84,7 @@ 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
+static u_int32_t
 ip_finddst(const struct ip *ip)
 {
        int length;
@@ -119,15 +117,48 @@ ip_finddst(const struct ip *ip)
                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(u_int32_t));
        return retval;
 }
 
+/*
+ * Compute a V4-style checksum by building a pseudoheader.
+ */
+int
+nextproto4_cksum(const struct ip *ip, const u_int8_t *data,
+                u_int len, u_int next_proto)
+{
+       struct phdr {
+               u_int32_t src;
+               u_int32_t dst;
+               u_char mbz;
+               u_char proto;
+               u_int16_t len;
+       } ph;
+       struct cksum_vec vec[2];
+
+       /* pseudo-header.. */
+       ph.len = htons((u_int16_t)len);
+       ph.mbz = 0;
+       ph.proto = next_proto;
+       UNALIGNED_MEMCPY(&ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
+       if (IP_HL(ip) == 5)
+               UNALIGNED_MEMCPY(&ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
+       else
+               ph.dst = ip_finddst(ip);
+
+       vec[0].ptr = (const u_int8_t *)(void *)&ph;
+       vec[0].len = sizeof(ph);
+       vec[1].ptr = data;
+       vec[1].len = len;
+       return (in_cksum(vec, 2));
+}
+
 static void
 ip_printts(register const u_char *cp, u_int length)
 {
@@ -137,17 +168,17 @@ ip_printts(register const u_char *cp, u_int length)
        const char *type;
 
        if (length < 4) {
-               printf("[bad length %d]", length);
+               printf("[bad length %u]", length);
                return;
        }
        printf(" TS{");
        hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
        if ((length - 4) & (hoplen-1))
-               printf("[bad length %d]", length);
+               printf("[bad length %u]", length);
        ptr = cp[2] - 1;
        len = 0;
        if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
-               printf("[bad ptr %d]", cp[2]);
+               printf("[bad ptr %u]", cp[2]);
        switch (cp[3]&0xF) {
        case IPOPT_TS_TSONLY:
                printf("TSONLY");
@@ -197,29 +228,37 @@ static void
 ip_optprint(register const u_char *cp, u_int length)
 {
        register u_int option_len;
+       const char *sep = "";
 
        for (; length > 0; cp += option_len, length -= option_len) {
                u_int option_code;
 
+               printf("%s", sep);
+               sep = ",";
+
                TCHECK(*cp);
                option_code = *cp;
 
+                printf("%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]);
-                       option_len = cp[1];                     
+                       option_len = cp[1];
+                       if (option_len < 2) {
+                               printf(" [bad length %u]", option_len);
+                               return;
+                       }
                }
 
-                printf("%s (%u) len %u",
-                       tok2str(ip_option_values,"unknown",option_code),
-                       option_code,
-                       option_len);
-
-                if (option_len < 2)
-                        return;
+               if (option_len > length) {
+                       printf(" [bad length %u]", option_len);
+                       return;
+               }
 
                 TCHECK2(*cp, option_len);
 
@@ -234,13 +273,17 @@ ip_optprint(register const u_char *cp, u_int length)
                case IPOPT_RR:       /* fall through */
                case IPOPT_SSRR:
                case IPOPT_LSRR:
-                       ip_printroute( cp, option_len);
+                       ip_printroute(cp, option_len);
                        break;
 
                case IPOPT_RA:
+                       if (option_len < 4) {
+                               printf(" [bad length %u]", option_len);
+                               break;
+                       }
                         TCHECK(cp[3]);
                         if (EXTRACT_16BITS(&cp[2]) != 0)
-                            printf("value %u", EXTRACT_16BITS(&cp[2]));
+                            printf(" value %u", EXTRACT_16BITS(&cp[2]));
                        break;
 
                case IPOPT_NOP:       /* nothing to print - fall through */
@@ -252,104 +295,12 @@ ip_optprint(register const u_char *cp, u_int length)
        return;
 
 trunc:
-       printf("[|ip]");
+       printf("%s", tstr);
 }
 
-/*
- * 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;
-}
-
-#ifndef IP_MF
-#define IP_MF 0x2000
-#endif /* IP_MF */
-#ifndef IP_DF
-#define IP_DF 0x4000
-#endif /* IP_DF */
 #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 */
@@ -369,6 +320,7 @@ ip_print_demux(netdissect_options *ndo,
               struct ip_print_demux_state *ipds)
 {
        struct protoent *proto;
+       struct cksum_vec vec[1];
 
 again:
        switch (ipds->nh) {
@@ -395,7 +347,7 @@ again:
                ipds->nh = enh & 0xff;
                goto again;
        }
-       
+
        case IPPROTO_IPCOMP:
        {
                int enh;
@@ -415,23 +367,25 @@ again:
        case IPPROTO_DCCP:
                dccp_print(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,
-                         (ipds->off &~ 0x6000));
+                         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,
-                         (ipds->off &~ 0x6000));
+                         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,
-                          (ipds->off &~ 0x6000));
+                          ipds->off & (IP_MF|IP_OFFMASK));
                break;
-               
+
        case IPPROTO_PIGP:
                /*
                 * XXX - the current IANA protocol number assignments
@@ -448,11 +402,11 @@ again:
                 */
                igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
                break;
-               
+
        case IPPROTO_EIGRP:
                eigrp_print(ipds->cp, ipds->len);
                break;
-               
+
        case IPPROTO_ND:
                ND_PRINT((ndo, " nd %d", ipds->len));
                break;
@@ -471,17 +425,17 @@ again:
 
        case IPPROTO_IPV4:
                /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
-               ip_print(gndo, ipds->cp, ipds->len);
+               ip_print(ndo, ipds->cp, ipds->len);
                if (! 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*/
 
@@ -499,11 +453,25 @@ again:
                break;
 
        case IPPROTO_PIM:
-               pim_print(ipds->cp,  ipds->len);
+               vec[0].ptr = ipds->cp;
+               vec[0].len = ipds->len;
+               pim_print(ipds->cp, ipds->len, in_cksum(vec, 1));
                break;
 
        case IPPROTO_VRRP:
-               vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
+               if (packettype == PT_CARP) {
+                       if (vflag)
+                               (void)printf("carp %s > %s: ",
+                                            ipaddr_string(&ipds->ip->ip_src),
+                                            ipaddr_string(&ipds->ip->ip_dst));
+                       carp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
+               } else {
+                       if (vflag)
+                               (void)printf("vrrp %s > %s: ",
+                                            ipaddr_string(&ipds->ip->ip_src),
+                                            ipaddr_string(&ipds->ip->ip_dst));
+                       vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
+               }
                break;
 
        case IPPROTO_PGM:
@@ -511,7 +479,7 @@ again:
                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));
@@ -519,7 +487,7 @@ again:
                break;
        }
 }
-              
+
 void
 ip_print_inner(netdissect_options *ndo,
               const u_char *bp,
@@ -551,6 +519,7 @@ ip_print(netdissect_options *ndo,
        struct ip_print_demux_state *ipds=&ipd;
        const u_char *ipend;
        u_int hlen;
+       struct cksum_vec vec[1];
        u_int16_t sum, ip_sum;
        struct protoent *proto;
 
@@ -563,8 +532,8 @@ ip_print(netdissect_options *ndo,
         else if (!eflag)
            printf("IP ");
 
-       if ((u_char *)(ipds->ip + 1) > snapend) {
-               printf("[|ip]");
+       if ((u_char *)(ipds->ip + 1) > ndo->ndo_snapend) {
+               printf("%s", tstr);
                return;
        }
        if (length < sizeof (struct ip)) {
@@ -601,8 +570,8 @@ 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;
 
@@ -625,7 +594,7 @@ ip_print(netdissect_options *ndo,
             }
 
             if (ipds->ip->ip_ttl >= 1)
-                (void)printf(", ttl %3u", ipds->ip->ip_ttl);    
+                (void)printf(", ttl %u", ipds->ip->ip_ttl);
 
            /*
             * for the firewall guys, print id, offset.
@@ -633,23 +602,25 @@ 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)",
+           (void)printf(", 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 ),
+                         bittok2str(ip_frag_values, "none", ipds->off&0xe000),
                          tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
                          ipds->ip->ip_p);
 
-            (void)printf(", length: %u", EXTRACT_16BITS(&ipds->ip->ip_len));
+            (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));
 
             if ((hlen - sizeof(struct ip)) > 0) {
-                printf(", options ( ");
+                printf(", options (");
                 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
-                printf(" )");
+                printf(")");
             }
 
-           if ((u_char *)ipds->ip + hlen <= snapend) {
-               sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
+           if (!Kflag && (u_char *)ipds->ip + hlen <= ndo->ndo_snapend) {
+               vec[0].ptr = (const u_int8_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,
@@ -657,7 +628,7 @@ ip_print(netdissect_options *ndo,
                }
            }
 
-            printf(") ");
+            printf(")\n    ");
        }
 
        /*
@@ -687,32 +658,31 @@ ip_print(netdissect_options *ndo,
            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)
+               if (!ndo->ndo_nflag && (proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
                    (void)printf(" %s", proto->p_name);
                else
                    (void)printf(" ip-proto-%d", ipds->ip->ip_p);
-           } 
+           }
        }
 }
 
 void
 ipN_print(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);
                return;
        }
-       memcpy (&hdr, (char *)ip, 4);
+       memcpy (&hdr, bp, 4);
        switch (IP_V(&hdr)) {
        case 4:
                ip_print (gndo, bp, length);
                return;
 #ifdef INET6
        case 6:
-               ip6_print (bp, length);
+               ip6_print (gndo, bp, length);
                return;
 #endif
        default: