print router-alert and ECN. re-write some. From [email protected]

diff --git a/print-ip.c b/print-ip.c
index 625095b62b2c2b3a076419a2fb571f3f75151371..3be539921368065fe59bfa44137764606f11afac 100644 (file)
--- a/print-ip.c
+++ b/print-ip.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.72 1999-10-30 07:36:37 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.73 1999-11-21 03:47:35 assar Exp $ (LBL)";
 #endif
 
 #include <sys/param.h>
@@ -201,18 +201,7 @@ igmp_print(register const u_char *bp, register u_int len,
        TCHECK2(bp[0], len);
        if (vflag) {
                /* Check the IGMP checksum */
-               u_int32_t sum = 0;
-               int count;
-               const u_short *sp = (u_short *)bp;
-               
-               for (count = len / 2; --count >= 0; )
-                       sum += *sp++;
-               if (len & 1)
-                       sum += ntohs(*(u_char *) sp << 8);
-               while (sum >> 16)
-                       sum = (sum & 0xffff) + (sum >> 16);
-               sum = 0xffff & ~sum;
-               if (sum != 0)
+               if (in_cksum((const u_short*)bp, len, 0))
                        printf(" bad igmp cksum %x!", EXTRACT_16BITS(&bp[2]));
        }
        return;
@@ -245,6 +234,56 @@ ip_printroute(const char *type, register const u_char *cp, u_int length)
        printf("%s}", ptr == len? "#" : "");
 }
 
+static void
+ip_printts(register const u_char *cp, u_int length)
+{
+       register u_int ptr = cp[2] - 1;
+       register u_int len;
+       int hoplen;
+       char *type;
+
+       printf(" TS{");
+       hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
+       if ((length - 4) & (hoplen-1))
+               printf("[bad length %d]", length);
+       if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
+               printf("[bad ptr %d]", cp[2]);
+       switch (cp[3]&0xF) {
+       case IPOPT_TS_TSONLY:
+               printf("TSONLY");
+               break;
+       case IPOPT_TS_TSANDADDR:
+               printf("TS+ADDR");
+               break;
+       case 2:
+               printf("PRESPEC2.0");
+               break;
+       case IPOPT_TS_PRESPEC:
+               printf("PRESPEC");
+               break;
+       default:        
+               printf("[bad ts type %d]", cp[3]&0xF);
+               goto done;
+       }
+
+       type = " ";
+       for (len = 4; len < length; len += hoplen) {
+               if (ptr == len)
+                       type = " ^ ";
+               printf("%s%d@%s", type, ntohl(*(u_int32_t *)&cp[len+hoplen-4]),
+                      hoplen!=8 ? "" : ipaddr_string(&cp[len]));
+               type = " ";
+       }
+
+done:
+       printf("%s", ptr == len ? " ^ " : "");
+
+       if (cp[3]>>4)
+               printf(" [%d hops not recorded]} ", cp[3]>>4);
+       else
+               printf("}");
+}
+
 /*
  * print IP options.
  */
@@ -278,15 +317,17 @@ ip_optprint(register const u_char *cp, u_int length)
                        break;
 
                case IPOPT_TS:
-                       printf(" TS{%d}", len);
+                       ip_printts(cp, len);
                        break;
 
+#ifndef IPOPT_SECURITY
+#define IPOPT_SECURITY 130
+#endif /* IPOPT_SECURITY */
                case IPOPT_SECURITY:
                        printf(" SECURITY{%d}", len);
                        break;
 
                case IPOPT_RR:
-                       printf(" RR{%d}=", len);
                        ip_printroute("RR", cp, len);
                        break;
 
@@ -298,6 +339,17 @@ ip_optprint(register const u_char *cp, u_int length)
                        ip_printroute("LSRR", cp, len);
                        break;
 
+#ifndef IPOPT_RA
+#define IPOPT_RA 148           /* router alert */
+#endif
+               case IPOPT_RA:
+                       printf(" RA");
+                       if (len != 4)
+                               printf("{%d}", len);
+                       else if (cp[2] || cp[3])
+                               printf("%d.%d", cp[2], cp[3]);
+                       break;
+
                default:
                        printf(" IPOPT-%d{%d}", cp[0], len);
                        break;
@@ -309,23 +361,34 @@ ip_optprint(register const u_char *cp, u_int length)
  * compute an IP header checksum.
  * don't modifiy the packet.
  */
-static int
-in_cksum(const struct ip *ip)
+u_short
+in_cksum(const u_short *addr, register int len, u_short csum)
 {
-       register const u_short *sp = (u_short *)ip;
-       register u_int32_t sum = 0;
-       register int count;
+       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);
 
        /*
-        * No need for endian conversions.
+        * add back carry outs from top 16 bits to low 16 bits
         */
-       for (count = ip->ip_hl * 2; --count >= 0; )
-               sum += *sp++;
-       while (sum > 0xffff)
-               sum = (sum & 0xffff) + (sum >> 16);
-       sum = ~sum & 0xffff;
-
-       return (sum);
+       sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
+       sum += (sum >> 16);                     /* add carry */
+       answer = ~sum;                          /* truncate to 16 bits */
+       return (answer);
 }
 
 /*
@@ -449,7 +512,7 @@ again:
                        break;
 
                case IPPROTO_ICMP:
-                       icmp_print(cp, (const u_char *)ip);
+                       icmp_print(cp, len, (const u_char *)ip);
                        break;
 
 #ifndef IPPROTO_IGRP
@@ -583,14 +646,30 @@ again:
                if (off & 0x1fff)
                        (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
                                      ipaddr_string(&ip->ip_dst));
+#ifndef IP_MF
+#define IP_MF 0x2000
+#endif /* IP_MF */
+#ifndef IP_DF
+#define IP_DF 0x4000
+#endif /* IP_DF */
                (void)printf(" (frag %d:%u@%d%s)", ntohs(ip->ip_id), len,
                        (off & 0x1fff) * 8,
                        (off & IP_MF)? "+" : "");
+
        } else if (off & IP_DF)
                (void)printf(" (DF)");
 
-       if (ip->ip_tos)
-               (void)printf(" [tos 0x%x]", (int)ip->ip_tos);
+       if (ip->ip_tos) {
+               (void)printf(" [tos 0x%x", (int)ip->ip_tos);
+               /* ECN bits */
+               if (ip->ip_tos&0x02) {
+                       (void)printf(",ECT");
+                       if (ip->ip_tos&0x01)
+                               (void)printf(",CE");
+               }
+               (void)printf("] ");
+       }
+
        if (ip->ip_ttl <= 1)
                (void)printf(" [ttl %d]", (int)ip->ip_ttl);
 
@@ -608,7 +687,7 @@ again:
                        sep = ", ";
                }
                if ((u_char *)ip + hlen <= snapend) {
-                       sum = in_cksum(ip);
+                       sum = in_cksum((const u_short *)ip, hlen, 0);
                        if (sum != 0) {
                                (void)printf("%sbad cksum %x!", sep,
                                             ntohs(ip->ip_sum));