Merged masquerading and generic SCTP support

diff --cc 6bed4router.c
index e06eec4,9a40d44..e001a68
--- 1/6bed4router.c
--- 2/6bed4router.c
+++ b/6bed4router.c
@@@ -109,14 -112,10 +112,16 @@@ struct 
                } idata;
                struct {
                        struct ip6_hdr v6hdr;
 +                      union {
 +                              struct icmp6_hdr v6icmphdr;
- #ifndef BE_SO_LAME_TO_SUPPRESS_SCTP
-                               struct sctphdr v6sctphdr;
- #endif
++                              struct my_sctphdr v6sctphdr;
 +                              struct tcphdr  v6tcphdr ;
 +                              struct udphdr  v6udphdr ;
 +                      } adata;
+                       struct icmp6_hdr v6icmphdr;
+                       struct my_sctphdr v6sctphdr;
+                       struct tcphdr  v6tcphdr ;
+                       struct udphdr  v6udphdr ;
                } ndata;
        } udata;
  } v4data6;
@@@ -594,59 -582,6 +599,57 @@@ void handle_4to6_nd (ssize_t v4ngbcmdle
  }
  
  
 +/*
 + * Forward a message to the masquerading target, or drop it.  This is done
 + * with non-6bed4 packets that are sent from a 6bed4peer node to its
 + * 6bed4router address; see is_mine() for the definition.  The general idea
 + * is that the address that is to be masqueraded can later be reconstructed
 + * from the 6bed4peer's address.
 + */
 +void handle_4to6_masquerading (ssize_t v4datalen) {
 +      fprintf (stderr, "Traffic to 6bed4router may be fit for masquerading\n");
 +      uint16_t *portpairs = NULL;
 +      uint16_t numpairs = 0;
 +      uint16_t port;
 +      switch (v4v6nexthdr) {
- #ifndef BE_SO_LAME_TO_SUPPRESS_SCTP
 +      case IPPROTO_SCTP:
 +              portpairs = masqportpairs [0];  // 's'
 +              numpairs  = num_masqportpairs [0];
 +              port = ntohs (v4v6sctpdstport);
 +              break;
- #endif
 +      case IPPROTO_TCP:
 +              portpairs = masqportpairs [1];  // 't'
 +              numpairs  = num_masqportpairs [1];
 +              port = ntohs (v4v6tcpdstport);
 +              break;
 +      case IPPROTO_UDP:
 +              portpairs = masqportpairs [2];  // 'u'
 +              numpairs  = num_masqportpairs [2];
 +              port = ntohs (v4v6udpdstport);
 +              break;
 +      default:
 +              break;
 +      }
 +      fprintf (stderr, "DEBUG: Looking for masquerading of port %d in %d entries\n", port, numpairs);
 +      while (numpairs-- > 0) {
 +              if ((port >= portpairs [0]) && (port <= portpairs [1])) {
 +                      //
 +                      // Replace masqueraded address by 6bed4router's
 +                      fprintf (stderr, "DEBUG: Passing traffic to masquerading address number %d\n", portpairs [2]);
 +                      memcpy (v4dst6, masqhost [portpairs [2]], 16);
 +                      //
 +                      // Forward immediately, and return from this function
 +printf ("Writing Masqueraded IPv6, result = %zd\n",
 +                      write (v6sox, &v4data6, sizeof (struct tun_pi) + v4datalen));
 +                      return;
 +              }
 +              portpairs += 3;
 +      }
 +      //
 +      // Silently skip the offered packet
 +}
 +
 +
  /* 
   * Forward a message received over the 6bed4 Network over IPv6.
   * Note that existing checksums will work well, as only the