grab upper layer protocol by chasing extension header chain.

from [email protected]

diff --git a/print-icmp6.c b/print-icmp6.c
index 69525c797eca1940e85e2a24b53375c6a4e4ea6c..79e6c6b0f63ba461910b19cc965b189a91972e71 100644 (file)
--- a/print-icmp6.c
+++ b/print-icmp6.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
 
 #ifndef lint
 static const char rcsid[] =

-    "@(#) $Header: /tcpdump/master/tcpdump/print-icmp6.c,v 1.28 2000-09-29 05:46:11 guy Exp $";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-icmp6.c,v 1.29 2000-10-03 02:17:50 itojun Exp $";

 #endif
 
 #ifdef HAVE_CONFIG_H
 #endif
 
 #ifdef HAVE_CONFIG_H


@@ -40,6 +40,8 @@ static const char rcsid[] =
 
 #include <netinet/in.h>
 
 
 #include <netinet/in.h>
 

+#include <netinet6/ah.h>
+

 #include <arpa/inet.h>
 
 #include <stdio.h>
 #include <arpa/inet.h>
 
 #include <stdio.h>


@@ -54,6 +56,7 @@ static const char rcsid[] =
 
 void icmp6_opt_print(const u_char *, int);
 void mld6_print(const u_char *);
 
 void icmp6_opt_print(const u_char *, int);
 void mld6_print(const u_char *);

+static struct udphdr *get_upperlayer(u_char *, int *);

 #ifdef HAVE_STRUCT_ICMP6_NODEINFO
 static void dnsname_print(const u_char *, const u_char *);
 void icmp6_nodeinfo_print(int, const u_char *, const u_char *);
 #ifdef HAVE_STRUCT_ICMP6_NODEINFO
 static void dnsname_print(const u_char *, const u_char *);
 void icmp6_nodeinfo_print(int, const u_char *, const u_char *);


@@ -111,7 +114,7 @@ icmp6_print(register const u_char *bp, register const u_char *bp2)
        register int hlen, dport;
        register const u_char *ep;
        char buf[256];
        register int hlen, dport;
        register const u_char *ep;
        char buf[256];

-       int icmp6len;
+       int icmp6len, prot;

 
 #if 0
 #define TCHECK(var) if ((u_char *)&(var) > ep - sizeof(var)) goto trunc
 
 #if 0
 #define TCHECK(var) if ((u_char *)&(var) > ep - sizeof(var)) goto trunc


@@ -162,11 +165,12 @@ icmp6_print(register const u_char *bp, register const u_char *bp2)
                               ip6addr_string(&oip->ip6_dst));
                        break;
                case ICMP6_DST_UNREACH_NOPORT:
                               ip6addr_string(&oip->ip6_dst));
                        break;
                case ICMP6_DST_UNREACH_NOPORT:

-                       TCHECK(oip->ip6_nxt);
-                       hlen = sizeof(struct ip6_hdr);
-                       ouh = (struct udphdr *)(((u_char *)oip) + hlen);
+                       if ((ouh = get_upperlayer((u_char *)oip, &prot))
+                           == NULL)
+                               goto trunc;
+

                        dport = ntohs(ouh->uh_dport);
                        dport = ntohs(ouh->uh_dport);

-                       switch (oip->ip6_nxt) {
+                       switch (prot) {

                        case IPPROTO_TCP:
                                printf("icmp6: %s tcp port %s unreachable",
                                        ip6addr_string(&oip->ip6_dst),
                        case IPPROTO_TCP:
                                printf("icmp6: %s tcp port %s unreachable",
                                        ip6addr_string(&oip->ip6_dst),


@@ -399,6 +403,79 @@ trunc:
 #endif
 }
 
 #endif
 }
 

+static struct udphdr *
+get_upperlayer(register u_char *bp, int *prot)
+{
+       register const u_char *ep;
+       struct ip6_hdr *ip6 = (struct ip6_hdr *)bp;
+       struct udphdr *uh;
+       struct ip6_hbh *hbh;
+       struct ip6_frag *fragh;
+       struct ah *ah;
+       int nh, hlen;
+
+       /* 'ep' points to the end of avaible data. */
+       ep = snapend;
+
+       if (TTEST(ip6->ip6_nxt) == 0)
+               return NULL;
+
+       nh = ip6->ip6_nxt;
+       hlen = sizeof(struct ip6_hdr);
+
+       while (bp < snapend) {
+               bp += hlen;
+
+               switch(nh) {
+               case IPPROTO_UDP:
+               case IPPROTO_TCP:
+                       uh = (struct udphdr *)bp;
+                       if (TTEST(uh->uh_dport)) {
+                               *prot = nh;
+                               return(uh);
+                       }
+                       else
+                               return(NULL);
+                       /* NOTREACHED */
+
+               case IPPROTO_HOPOPTS:
+               case IPPROTO_DSTOPTS:
+               case IPPROTO_ROUTING:
+                       hbh = (struct ip6_hbh *)bp;
+                       if (TTEST(hbh->ip6h_len) == 0)
+                               return(NULL);
+                       nh = hbh->ip6h_nxt;
+                       hlen = (hbh->ip6h_len + 1) << 3;
+                       break;
+
+               case IPPROTO_FRAGMENT: /* this should be odd, but try anyway */
+                       fragh = (struct ip6_frag *)bp;
+                       if (TTEST(fragh->ip6f_offlg) == 0)
+                               return(NULL);
+                       /* fragments with non-zero offset are meaningless */
+                       if ((fragh->ip6f_offlg & IP6F_OFF_MASK) != 0)
+                               return(NULL);
+                       nh = fragh->ip6f_nxt;
+                       hlen = sizeof(struct ip6_frag);
+                       break;
+
+               case IPPROTO_AH:
+                       ah = (struct ah *)bp;
+                       if (TTEST(ah->ah_len) == 0)
+                               return(NULL);
+                       nh = ah->ah_nxt;
+                       hlen = (ah->ah_len + 2) << 2;
+                       break;
+
+               default:        /* unknown or undecodable header */
+                       *prot = nh; /* meaningless, but set here anyway */
+                       return(NULL);
+               }
+       }
+
+       return(NULL);           /* should be notreached, though */
+}
+

 void
 icmp6_opt_print(register const u_char *bp, int resid)
 {
 void
 icmp6_opt_print(register const u_char *bp, int resid)
 {