/*******************************************************************************
 *
 * Copyright (c) 2013 Robert Krause (ruport@f00l.de)
 *
 * This file is part of Netmate.
 *
 * Netmate is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or any later version.
 *
 * Netmate is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * Netmate. If not, see http://www.gnu.org/licenses/.
 *
 ******************************************************************************/

/******************************************************************************/
/* netmate layer3 protocols */
/******************************************************************************/

char *ipprotocol(unsigned char id);
char *ipv4_optclass(unsigned char id);
char *ipv4_optnumber(unsigned char id);
char *ipv4_optdata(unsigned char number, char *optdata);
char *ipv6_hopopt_type(unsigned char id);
char *arp_operation(unsigned char id);
char *icmp_type(unsigned char id);
char *icmp_code(unsigned char type, unsigned char code);
char *icmpv6_type(unsigned char id);
char *icmpv6_code(unsigned char type, unsigned char code);
char *icmpv6_opttype(unsigned char id);
GtkGrid *ipv4_grid(struct iphdr *ipv4, u_char *options);				/* ipv4 (type 0x0800) */
GtkGrid *ipv6_grid(struct ip6_hdr *ipv6, u_char *options);				/* ipv6 (type 0x08dd) */
GtkGrid *arp_grid(struct arphdr *arp, u_char *options);					/* arp (type 0x0806) */
GtkGrid *icmp_grid(struct icmphdr *icmp, u_char *options, int left);	/* icmp */
GtkGrid *icmpv6_grid(struct icmp6_hdr *icmpv6, u_char *options, int left);		/* icmp */

/******************************************************************************/

/* taken from http://en.wikipedia.org/wiki/List_of_IP_protocol_numbers */
char *ipprotocol(unsigned char id) {
  switch (id) {
    case 0:
      return("HOPOPT");
    case 1:
      return("ICMP");
    case 2:
      return("IGMP");
    case 3:
      return("GGP");
    case 4:
      return("IPv4");
    case 5:
      return("ST");
    case 6:
      return("TCP");
    case 7:
      return("CBT");
    case 8:
      return("EGP");
    case 9:
      return("IGP");
    case 10:
      return("BBN-RCC-MON");
    case 11:
      return("NVP-II");
    case 12:
      return("PUP");
    case 13:
      return("ARGUS");
    case 14:
      return("EMCON");
    case 15:
      return("XNET");
    case 16:
      return("CHAOS");
    case 17:
      return("UDP");
    case 18:
      return("MUX");
    case 19:
      return("DCN-MEAS");
    case 20:
      return("HMP");
    case 21:
      return("PRM");
    case 22:
      return("XNS-IDP");
    case 23:
      return("TRUNK-1");
    case 24:
      return("TRUNK-2");
    case 25:
      return("LEAF-1");
    case 26:
      return("LEAF-2");
    case 27:
      return("RDP");
    case 28:
      return("IRTP");
    case 29:
      return("ISO-TP4");
    case 30:
      return("NETBLT");
    case 31:
      return("MFE-NSP");
    case 32:
      return("MERIT-INP");
    case 33:
      return("DCCP");
    case 34:
      return("3PC");
    case 35:
      return("IDPR");
    case 36:
      return("XTP");
    case 37:
      return("DDP");
    case 38:
      return("IDPR-CMTP");
    case 39:
      return("TP++");
    case 40:
      return("IL");
    case 41:
      return("IPv6");
    case 42:
      return("SDRP");
    case 43:
      return("IPv6-Route");
    case 44:
      return("IPv6-Frag");
    case 45:
      return("IDRP");
    case 46:
      return("RSVP");
    case 47:
      return("GRE");
    case 48:
      return("MHRP");
    case 49:
      return("BNA");
    case 50:
      return("ESP");
    case 51:
      return("AH");
    case 52:
      return("I-NLSP");
    case 53:
      return("SWIPE");
    case 54:
      return("NARP");
    case 55:
      return("MOBILE");
    case 56:
      return("TLSP");
    case 57:
      return("SKIP");
    case 58:
      return("IPv6-ICMP");
    case 59:
      return("IPv6-NoNxt");
    case 60:
      return("IPv6-Opts");
    case 61:
      return("Any host internal protocol");
    case 62:
      return("CFTP");
    case 63:
      return("Any local network");
    case 64:
      return("SAT-EXPAK");
    case 65:
      return("KRYPTOLAN");
    case 66:
      return("RVD");
    case 67:
      return("IPPC");
    case 68:
      return("Any distributed file system");
    case 69:
      return("SAT-MON");
    case 70:
      return("VISA");
    case 71:
      return("IPCV");
    case 72:
      return("CPNX");
    case 73:
      return("CPHB");
    case 74:
      return("WSN");
    case 75:
      return("PVP");
    case 76:
      return("BR-SAT-MON");
    case 77:
      return("SUN-ND");
    case 78:
      return("WB-MON");
    case 79:
      return("WB-EXPAK");
    case 80:
      return("ISO-IP");
    case 81:
      return("VMTP");
    case 82:
      return("SECURE-VMTP");
    case 83:
      return("VINES");
    case 84:
      return("TTP");
    case 85:
      return("NSFNET-IGP");
    case 86:
      return("DGP");
    case 87:
      return("TCF");
    case 88:
      return("EIGRP");
    case 89:
      return("OSPF");
    case 90:
      return("Sprite-RPC");
    case 91:
      return("LARP");
    case 92:
      return("MTP");
    case 93:
      return("AX.25");
    case 94:
      return("IPIP");
    case 95:
      return("MICP");
    case 96:
      return("SCC-SP");
    case 97:
      return("ETHERIP");
    case 98:
      return("ENCAP");
    case 99:
      return("Any private encryption scheme");
    case 100:
      return("GMTP");
    case 101:
      return("IFMP");
    case 102:
      return("PNNI");
    case 103:
      return("PIM");
    case 104:
      return("ARIS");
    case 105:
      return("SCPS");
    case 106:
      return("QNX");
    case 107:
      return("A/N");
    case 108:
      return("IPComp");
    case 109:
      return("SNP");
    case 110:
      return("Compaq-Peer");
    case 111:
      return("IPX-in-IP");
    case 112:
      return("VRRP");
    case 113:
      return("PGM");
    case 114:
      return("Any 0-hop protocol");
    case 115:
      return("L2TP");
    case 116:
      return("DDX");
    case 117:
      return("IATP");
    case 118:
      return("STP");
    case 119:
      return("SRP");
    case 120:
      return("UTI");
    case 121:
      return("SMP");
    case 122:
      return("SM");
    case 123:
      return("PTP");
    case 124:
      return("IS-IS over IPv4");
    case 125:
      return("FIRE");
    case 126:
      return("CRTP");
    case 127:
      return("CRUDP");
    case 128:
      return("SSCOPMCE");
    case 129:
      return("IPLT");
    case 130:
      return("SPS");
    case 131:
      return("PIPE");
    case 132:
      return("SCTP");
    case 133:
      return("FC");
    case 134:
      return("RSVP-E2E-IGNORE");
    case 135:
      return("Mobility Header");
    case 136:
      return("UDPLite");
    case 137:
      return("MPLS-in-IP");
    case 138:
      return("manet");
    case 139:
      return("HIP");
    case 140:
      return("Shim6");
    case 141:
      return("WESP");
    case 142:
      return("ROHC");
    case 253:
      return("experimentation and testing");
    case 254:
      return("experimentation and testing");
    case 255:
      return("Reserved");
  }
  return("UNKNOWN");
}

char *ipv4_optclass(unsigned char id) {
  switch (id) {
    case 0:
      return("ctrl");
    case 1:
      return("res");
    case 2:
      return("debug");
    case 3:
      return("res");
  }
  return("UNKNOWN");
}

char *ipv4_optnumber(unsigned char id) {
  switch (id) {
    case 0:
      return("EOOL");
    case 1:
      return("NOP");
    case 2:
      return("SEC");
    case 3:
      return("LSR");
    case 4:
      return("TS");
    case 5:
      return("E-SEC");
    case 6:
      return("CIPSO");
    case 7:
      return("RR");
    case 8:
      return("SID");
    case 9:
      return("SSR");
    case 10:
      return("ZSU");
    case 11:
      return("MTUP");
    case 12:
      return("MTUR");
    case 13:
      return("FINN");
    case 14:
      return("VISA");
    case 15:
      return("ENCODE");
    case 16:
      return("IMITD");
    case 17:
      return("EIP");
    case 18:
      return("TR");
    case 19:
      return("ADDEXT");
    case 20:
      return("RTRALT");
    case 21:
      return("SDB");
    case 23:
      return("DPS");
    case 24:
      return("UMP");
    case 25:
      return("QS");
    case 30:
      return("EXP");
  }
  return("UNKNOWN");
}

char *ipv6_hopopt_type(unsigned char id) {
  switch (id) {
    case 0x00:
      return("Pad1");
    case 0x01:
      return("PadN");
    case 0xc2:
      return("Jumbo Payload");
    case 0x63:
      return("RPL Option");
    case 0x04:
      return("Tunnel Encapsulation Limit");
    case 0x05:
      return("Router Alert");
    case 0x26:
      return("Quick-Start");
    case 0x07:
      return("CALIPSO");
    case 0x08:
      return("SMF_DPD");
    case 0xc9:
      return("Home Address");
    case 0x8a:
      return("Endpoint Identification");
    case 0x8b:
      return("ILNP Nonce");
    case 0x8c:
      return("Line-Identification Option");
    case 0x4d:
      return("Deprecated");
    case 0x6d:
      return("MPL Option");
    case 0xee:
      return("IP_DFF");
    case 0x1e:
    case 0x3e:
    case 0x5e:
    case 0x7e:
    case 0x9e:
    case 0xbe:
    case 0xde:
    case 0xfe:
      return("RFC3692-style Experiment");
  }
  return("UNKNOWN");
}

char *ipv4_optdata(unsigned char number, char *optdata) {
  switch (number) {
    /* 0 and 1 do not have option data */
    case 20:
      if (strcmp(optdata, "0000") == 0) return("Router shall examine packet");
      return("Reserved");
  }
  return("UNKNOWN");
}

char *arp_operation(unsigned char id) {
  switch (id) {
    case 1:
      return("request");
    case 2:
      return("reply");
  }
  return("UNKNOWN");
}

char *icmp_type(unsigned char id) {
  switch (id) {
    case 0:
      return("Echo Reply");
    case 3:
      return("Destination Unreachable");
    case 4:
      return("Source Quench");
    case 5:
      return("Redirect");
    case 6:
      return("Alternate Host Address)");
    case 8:
      return("Echo");
    case 9:
      return("Router Advertisement");
    case 10:
      return("Router Selection");
    case 11:
      return("Time Exceeded");
    case 12:
      return("Parameter Problem");
    case 13:
      return("Timestamp");
    case 14:
      return("Timestamp Reply");
    case 15:
      return("Information Request");
    case 16:
      return("Information Reply");
    case 17:
      return("Address Mask Request");
    case 18:
      return("Address Mask Reply");
    case 30:
      return("Traceroute");
    case 31:
      return("Datagram Conversion Error");
    case 32:
      return("Mobile Host Redirect");
    case 33:
      return("IPv6 Where-Are-You");
    case 34:
      return("IPv6 I-Am-Here");
    case 35:
      return("Mobile Registration Request");
    case 36:
      return("Mobile Registration Reply");
    case 37:
      return("Domain Name Request");
    case 38:
      return("Domain Name Reply");
    case 39:
      return("SKIP");
    case 40:
      return("Photuris");
  }
  return("UNKNOWN");
}

char *icmp_code(unsigned char type, unsigned char code) {
  switch (type) {
    case 0:
    case 4:
    case 8:
    case 10:
    case 13:
    case 14:
    case 15:
    case 16:
    case 17:
    case 18:
      if (code == 0) return("No code");
      break;
    case 3:
      switch (code) {
        case 0:
          return("Net Unreachable");
        case 1:
          return("Host Unreachable");
        case 2:
          return("Protocol Unreachable");
        case 3:
          return("Port Unreachable");
        case 4:
          return("Fragmentation Needed and Don't Fragment was Set");
        case 5:
          return("Source Route Failed");
        case 6:
          return("Destination Network Unknown");
        case 7:
          return("Destination Host Unknown");
        case 8:
          return("Source Host Isolated");
        case 9:
          return("Communication with Destination Network is Administratively Prohibited");
        case 10:
          return("Communication with Destination Host is Administratively Prohibited");
        case 11:
          return("Destination Network Unreachable for Type of Service");
        case 12:
          return("Destination Host Unreachable for Type of Service");
        case 13:
          return("Communication Administratively Prohibited");
        case 14:
          return("Host Precedence Violation");
        case 15:
          return("Precedence cutoff in effect");
      }
      break;
    case 5:
      switch (code) {
        case 0:
          return("Redirect Datagram for the Network (or subnet)");
        case 1:
          return("Redirect Datagram for the Host");
        case 2:
          return("Redirect Datagram for the Type of Service and Network");
        case 3:
          return("Redirect Datagram for the Type of Service and Host");
      }
      break;
    case 6:
      if (code == 0) return("Alternate Address for Host");
      break;
    case 9:
      if (code == 0) return("Normal router advertisement");
      if (code == 16) return("Does not route common traffic");
      break;
    case 11:
      if (code == 0) return("Time to Live exceeded in Transit");
      if (code == 1) return("Fragment Reassembly Time Exceeded");
      break;
    case 12:
      if (code == 0) return("Pointer indicates the error");
      if (code == 1) return("Missing a Required Option");
      if (code == 2) return("Bad Length");
      break;
    case 40:
      switch (code) {
        case 0:
          return("Bad SPI");
        case 1:
          return("Authentication Failed");
        case 2:
          return("Decompression Failed");
        case 3:
          return("Decryption Failed");
        case 4:
          return("Need Authentication");
        case 5:
          return("Need Authorization");
      }
      break;
  }
  return("UNKNOWN");
}

char *icmpv6_type(unsigned char id) {
  switch (id) {
    case 0:
      return("Reserved");
    case 1:
      return("Destination Unreachable");
    case 2:
      return("Packet Too Big");
    case 3:
      return("Time Exceeded");
    case 4:
      return("Parameter Problem");
    case 100:
    case 101:
    case 200:
    case 201:
      return("Private experimentation");
    case 127:
      return("Reserved for expansion of ICMPv6 error messages");
    case 128:
      return("Echo Request");
    case 129:
      return("Echo Reply");
    case 130:
      return("Multicast Listener Query");
    case 131:
      return("Multicast Listener Report");
    case 132:
      return("Multicast Listener Done");
    case 133:
      return("Router Solicitation");
    case 134:
      return("Router Advertisement");
    case 135:
      return("Neighbor Solicitation");
    case 136:
      return("Neighbor Advertisement");
    case 137:
      return("Redirect Message");
    case 138:
      return("Router Renumbering");
    case 139:
      return("ICMP Node Information Query");
    case 140:
      return("ICMP Node Information Response");
    case 141:
      return("Inverse Neighbor Discovery Solicitation Message");
    case 142:
      return("Inverse Neighbor Discovery Advertisement Message");
    case 143:
      return("Version 2 Multicast Listener Report");
    case 144:
      return("Home Agent Address Discovery Request Message");
    case 145:
      return("Home Agent Address Discovery Reply Message");
    case 146:
      return("Mobile Prefix Solicitation");
    case 147:
      return("Mobile Prefix Advertisement");
    case 148:
      return("Certification Path Solicitation Message");
    case 149:
      return("Certification Path Advertisement Message");
    case 150:
      return("ICMP messages utilized by experimental mobility protocols");
    case 151:
      return("Multicast Router Advertisement");
    case 152:
      return("Multicast Router Solicitation");
    case 153:
      return("Multicast Router Termination");
    case 154:
      return("FMIPv6 Messages");
    case 155:
      return("RPL Control Message");
    case 156:
      return("ILNPv6 Locator Update Message");
    case 157:
      return("Duplicate Address Request");
    case 158:
      return("Duplicate Address Confirmation");
    case 255:
      return("Reserved for expansion of ICMPv6 informational messages");
  }
  return("UNKNOWN");
}

char *icmpv6_code(unsigned char type, unsigned char code) {
  switch (type) {
    case 0:
    case 2:
    case 128:
    case 129:
    case 130:
    case 131:
    case 132:
    case 133:
    case 134:
    case 135:
    case 136:
    case 137:
    case 141:
    case 142:
    case 143:
    case 144:
    case 145:
    case 146:
    case 147:
      if (code == 0) return("No code");
      break;
    case 1:
      switch (code) {
        case 0:
          return("no route to destination");
        case 1:
          return("communication with destination administratively prohibited");
        case 2:
          return("beyond scope of source address");
        case 3:
          return("address unreachable");
        case 4:
          return("port unreachable");
        case 5:
          return("source address failed ingress/egress policy");
        case 6:
          return("reject route to destination");
        case 7:
          return("error in source routing header");
      }
      break;
    case 3:
      if (code == 0) return("hop limit exceeded in transit");
      if (code == 1) return("fragment reassembly time exceeded");
      break;
    case 4:
      if (code == 0) return("erroneous header field encountered");
      if (code == 1) return("unrecognized Next Header type encountered");
      if (code == 2) return("unrecognized IPv6 option encountered");
      break;
    case 138:
      if (code == 0) return("Router Renumbering Command");
      if (code == 1) return("Router Renumbering Result");
      if (code == 255) return("Sequence Number Reset");
      break;
    case 139:
      if (code == 0) return("The Data field contains an IPv6 address which is the Subject of this Query.");
      if (code == 1) return("The Data field contains a name which is the Subject of this Query, or is empty, as in the case of a NOOP.");
      if (code == 2) return("The Data field contains an IPv4 address which is the Subject of this Query.");
      break;
    case 140:
      if (code == 0) return("A successful reply. The Reply Data field may or may not be empty.");
      if (code == 1) return("The Responder refuses to supply the answer. The Reply Data field will be empty.");
      if (code == 2) return("The Qtype of the Query is unknown to the Responder. The Reply Data field will be empty.");
      break;
    case 154:
      switch (code) {
        case 0:
        case 1:
          return("Reserved");
        case 2:
          return("RtSolPr");
        case 3:
          return("PrRtAdv");
        case 4:
          return("HI - Deprecated");
        case 5:
          return("HAck - Deprecated");
      }
      break;
  }
  return("UNKNOWN");
}

char *icmpv6_opttype(unsigned char id) {
  switch (id) {
    case 1:
      return("Source Link-Layer Address");
    case 2:
      return("Target Link-Layer Address");
    case 3:
      return("Prefix Information");
    case 4:
      return("Redirected Header");
    case 5:
      return("MTU");
  }
  return("UNKNOWN");
}


GtkGrid *ipv4_grid(struct iphdr *ipv4, u_char *options) {
  GtkGrid *grid;		/* the grid itself	 */
  char *label;			/* label of buttons to set */
  char ipv4_dscp;		/* ip dscp field */
  char ipv4_ecn;		/* ip ecn field */
  char *optdata;		/* option data */
  short ipv4_offset;	/* ip fragment offset */
  int x,y;				/* position pointer to next empty grid cell */
  int left;				/* bytes left for ipv4 options */
  int optlen;			/* length of options field */
  int opttype;			/* option type */
  int i;				/* loop counter for raw data representation */

  /* init new empty grid */
  grid = GTK_GRID(gtk_grid_new());

  /* set columns to be uniform sized (for better bit size representation) */
  gtk_grid_set_column_homogeneous(grid, TRUE);

  /* allocate memory for button label */
  label = malloc(100);

  /* build bit indication topic line (0 1 2 .. 31) */
  for (x=0; x<32; x++) {
    sprintf(label, "%u", x);
    gtk_grid_attach(grid, gtk_label_new(label), x, 0, 1, 1);
  }

  /* set cell pointer to next empty grid cell */
  x=0;
  y=1;

  /* read and set ip version field */
  sprintf(label, "Version: %u", ipv4->version);
  append_field(grid, &x, &y, 4, label, IPV4_VERSION);

  /* read and set ip header length (<< 2 to calculate real size) */
  sprintf(label, "IHL: %u (%u bytes)", ipv4->ihl, ipv4->ihl*4);
  append_field(grid, &x, &y, 4, label, IPV4_IHL);

  /* read and set ip dscp field */
  ipv4_dscp = ipv4->tos >> 2;
  sprintf(label, "DSCP: 0x%02x", ipv4_dscp);
  append_field(grid, &x, &y, 6, label, IPV4_DCSP);

  /* read and set ip ecn field */
  ipv4_ecn = ipv4->tos & 0x03;
  sprintf(label, "ECN:\n0x%02x", ipv4_ecn);
  append_field(grid, &x, &y, 2, label, IPV4_ECN);

  /* read and set total length of ip header */
  sprintf(label, "Total Length: %u", htons(ipv4->tot_len));
  append_field(grid, &x, &y, sizeof(ipv4->tot_len)*8, label, IPV4_TOTLEN);

  /* read and set identification field of ip packet */
  sprintf(label, "Identification: 0x%04x", htons(ipv4->id));
  append_field(grid, &x, &y, sizeof(ipv4->id)*8, label, IPV4_IDENTIFICATION);

  /* reserved flag */
  if (ipv4->frag_off & htons(IP_RF)) {
    append_field(grid, &x, &y, 1, "RF", IPV4_FLAG_RESERVED);
  } else {
    append_field(grid, &x, &y, 1, "rf", IPV4_FLAG_RESERVED);
  }

  /* dont fragment flag */
  if (ipv4->frag_off & htons(IP_DF)) {
    append_field(grid, &x, &y, 1, "DF", IPV4_FLAG_DF);
  } else {
    append_field(grid, &x, &y, 1, "df", IPV4_FLAG_DF);
  }

  /* more fragments flag */
  if (ipv4->frag_off & htons(IP_MF)) {
    append_field(grid, &x, &y, 1, "MF", IPV4_FLAG_MF);
  } else {
    append_field(grid, &x, &y, 1, "mf", IPV4_FLAG_MF);
  }

  /* read and set ip fragmentation offset (<< 3 to calculate real size); */
  ipv4_offset = (htons(ipv4->frag_off) & IP_OFFMASK);
  sprintf(label, "Fragment Offset: %u (%u bytes)", ipv4_offset, ipv4_offset << 3);
  append_field(grid, &x, &y, 13, label, IPV4_FRAGOFF);

  /* read and set time to live of ip packet */
  sprintf(label, "Time To Live: %u", ipv4->ttl);
  append_field(grid, &x, &y, sizeof(ipv4->ttl)*8, label, IPV4_TTL);

  /* read an d set upper layer protocol */
  sprintf(label, "Protocol: %u (%s)", ipv4->protocol, ipprotocol(ipv4->protocol));
  append_field(grid, &x, &y, sizeof(ipv4->protocol)*8, label, IPV4_PROTOCOL);

  /* read and set ip header checksum */
  sprintf(label, "Header checksum: 0x%04x", htons(ipv4->check));
  append_field(grid, &x, &y, sizeof(ipv4->check)*8, label, IPV4_CHECKSUM);

  /* read and set ip source address */
  sprintf(label, "Source IP Address: %u.%u.%u.%u", ipv4->saddr & 0xff, (ipv4->saddr >> 8) & 0xff, (ipv4->saddr >> 16) & 0xff, (ipv4->saddr >> 24) & 0xff);
  append_field(grid, &x, &y, sizeof(ipv4->saddr)*8, label, IPV4_SOURCE);

  /* read and set ip destination address */
  sprintf(label, "Destination IP Address: %u.%u.%u.%u", ipv4->daddr & 0xff, (ipv4->daddr >> 8) & 0xff, (ipv4->daddr >> 16) & 0xff, (ipv4->daddr >> 24) & 0xff);
  append_field(grid, &x, &y, sizeof(ipv4->daddr)*8, label, IPV4_DESTINATION);

  /* count bytes of option fields */
  left = (ipv4->ihl-0x05)*4;

  /* progress bytes until no option bytes left */
  while (left > 0) {
    /* get option type (first byte) */
    opttype = options[0];

    /* copy bit (bit 1) */
    if (opttype & IPOPT_COPY) {
      append_field(grid, &x, &y, 1, "C", IPV4_OPTION_FLAG_COPIED);
    } else {
      append_field(grid, &x, &y, 1, "c", IPV4_OPTION_FLAG_COPIED);
    }

    /* option class (bit 2 & 3) */
    sprintf(label, "Class: %u (%s)", opttype & IPOPT_CLASS_MASK, ipv4_optclass(opttype & IPOPT_CLASS_MASK));
    append_field(grid, &x, &y, 2, label, IPV4_OPTION_CLASS);

    /* option number (bit 4-8) */
    sprintf(label, "Number: %u (%s)", opttype & IPOPT_NUMBER_MASK, ipv4_optnumber(opttype & IPOPT_NUMBER_MASK));
    append_field(grid, &x, &y, 5, label, IPV4_OPTION_NUMBER);

    /* end of options AND no operation do not have further fields */
    if (((opttype & IPOPT_NUMBER_MASK) == 0) || ((opttype & IPOPT_NUMBER_MASK) == 1)) continue;

    /* options length (INCLUDING type & length fields) */
    optlen = options[1];
    sprintf(label, "Length: %u", optlen);
    append_field(grid, &x, &y, 8, label, IPV4_OPTION_LENGTH);

    /* allocate memory for option data (*2 because of hex representation) */
    optdata = malloc(optlen*2);

    /* print bytes in hex format into array */
    for (i=0; i<optlen-2; ++i) sprintf(&optdata[i*2], "%02x", (unsigned int)options[i+2]);
    optdata[(optlen-2)*2] = 0x00;

    /* option data field */
    sprintf(label, "Opt. Data 0x%s (%s)", optdata, ipv4_optdata(opttype & IPOPT_NUMBER_MASK, optdata));
    append_field(grid, &x, &y, (optlen-2)*8, label, IPV4_OPTION_DATA);

    /* free data */
    free(optdata);

    /* reduce length of field */
    left -= optlen;

    /* increase pointer to options header */
    options = options + optlen;
  }

  /* free memory of label */
  free(label);

  /* show ethernet grid (tab) */
  gtk_widget_show_all(GTK_WIDGET(grid));

  /* pass grid back to tab builder function */
  return(grid);
}

GtkGrid *ipv6_grid(struct ip6_hdr *ipv6, u_char *options) {
  GtkGrid *grid;	/* the grid itself */
  char *label;		/* label of buttons to set */
  int x,y;			/* position pointer to next empty grid cell */
  char *optdata;
  int i;
  int optlen;
  int opttype;
  int hoplen;
  int left;
  int ipv6_version;
  int ipv6_tc;
  int ipv6_fl;
  int ipv6_nh;

  /* init new empty grid */
  grid = GTK_GRID(gtk_grid_new());

  /* set columns to be uniform sized (for better bit size representation) */
  gtk_grid_set_column_homogeneous(grid, TRUE);

  /* allocate memory for button label */
  label = malloc(100);

  /* build bit indication topic line (0 1 2 .. 31) */
  for (x=0; x<32; x++) {
    sprintf(label, "%u", x);
    gtk_grid_attach(grid, gtk_label_new(label), x, 0, 1, 1);
  }

  /* set cell pointer to next empty grid cell */
  x=0;
  y=1;

  /* read and set ip version field */
  ipv6_version = htonl(ipv6->ip6_ctlun.ip6_un1.ip6_un1_flow) >> 28;
  sprintf(label, "Version: %u", ipv6_version);
  append_field(grid, &x, &y, 4, label, IPV6_VERSION);

  /* traffic class */
  ipv6_tc = htonl(ipv6->ip6_ctlun.ip6_un1.ip6_un1_flow) >> 20 & 0x00ff;
  sprintf(label, "Traffic Class: 0x%02x", ipv6_tc);
  append_field(grid, &x, &y, 8, label, IPV6_TC);

  /* flow label */
  ipv6_fl = htonl(ipv6->ip6_ctlun.ip6_un1.ip6_un1_flow) & 0x000fffff;
  sprintf(label, "Flow Label: 0x%06x", ipv6_fl);
  append_field(grid, &x, &y, 20, label, IPV6_FLOW);

  /* payload length */
  sprintf(label, "Payload Length: %u", htons(ipv6->ip6_ctlun.ip6_un1.ip6_un1_plen));
  append_field(grid, &x, &y, sizeof(ipv6->ip6_ctlun.ip6_un1.ip6_un1_plen)*8, label, IPV6_PAYLEN);

  /* next header */
  ipv6_nh = ipv6->ip6_ctlun.ip6_un1.ip6_un1_nxt;
  sprintf(label, "Next Header: %u (%s)", ipv6_nh, ipprotocol(ipv6_nh));
  append_field(grid, &x, &y, sizeof(ipv6->ip6_ctlun.ip6_un1.ip6_un1_nxt)*8, label, IPV6_NEXT_HEADER);

  /* hop limit */
  sprintf(label, "Hop Limit: %u", ipv6->ip6_ctlun.ip6_un1.ip6_un1_hlim);
  append_field(grid, &x, &y, sizeof(ipv6->ip6_ctlun.ip6_un1.ip6_un1_hlim)*8, label, IPV6_HOP_LIMIT);

  /* source address */
  sprintf(label, "Source Address: %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", htons(ipv6->ip6_src.__in6_u.__u6_addr16[0]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[1]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[2]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[3]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[4]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[5]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[6]), htons(ipv6->ip6_src.__in6_u.__u6_addr16[7]));
  append_field(grid, &x, &y, 128, label, IPV6_SOURCE);

  /* destination address */
  sprintf(label, "Destination Address: %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", htons(ipv6->ip6_dst.__in6_u.__u6_addr16[0]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[1]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[2]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[3]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[4]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[5]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[6]), htons(ipv6->ip6_dst.__in6_u.__u6_addr16[7]));
  append_field(grid, &x, &y, 128, label, IPV6_DESTINATION);

  while (ipv6_nh == IPPROTO_HOPOPTS) {
    /* next header */
    ipv6_nh = options[0];
    sprintf(label, "Next Header: %u (%s)", ipv6_nh, ipprotocol(ipv6_nh));
    append_field(grid, &x, &y, sizeof(ipv6->ip6_ctlun.ip6_un1.ip6_un1_nxt)*8, label, IPV6_NEXT_HEADER);

    /* options length */
    hoplen = options[1];
    sprintf(label, "Length: %u (%u bytes)", hoplen, hoplen*8);
    append_field(grid, &x, &y, 8, label, IPV6_HDR_EXT_LEN);
    options += 2;

    left = hoplen*8 + 6;
    while (left > 0) {
      opttype = options[0];
      sprintf(label, "Type: %u (%s)", opttype, ipv6_hopopt_type(opttype));
      append_field(grid, &x, &y, 8, label, IPV6_OPTION_TYPE);

      optlen = options[1];
      sprintf(label, "Length: %u", optlen);
      append_field(grid, &x, &y, 8, label, IPV6_OPTION_LENGTH);

      if (optlen > 0) {
        optdata = malloc(optlen*2+1);

        for (i=0; i<optlen; ++i) sprintf(&optdata[i*2], "%02x", (unsigned int)options[i+2]);
        optdata[optlen*2] = 0x00;

        sprintf(label, "Data: 0x%s", optdata);
        append_field(grid, &x, &y, optlen*8, label, IPV6_OPTION_DATA);

        free(optdata);
      }

      options += 2 + optlen;
      left -= 2 + optlen;
    }

  }

  /* free memory of label */
  free(label);

  /* show ethernet grid (tab) */
  gtk_widget_show_all(GTK_WIDGET(grid));

  /* pass grid back to tab builder function */
  return(grid);
}

GtkGrid *arp_grid(struct arphdr *arp, u_char *options) {
  GtkGrid *grid;	/* the grid itself */
  char *label;		/* label of buttons to set */
  int x,y;			/* position pointer to next empty grid cell */

  /* init new empty grid */
  grid = GTK_GRID(gtk_grid_new());

  /* set columns to be uniform sized (for better bit size representation) */
  gtk_grid_set_column_homogeneous(grid, TRUE);

  /* allocate memory for button label */
  label = malloc(100);

  /* build bit indication topic line (0 1 2 .. 31) */
  for (x=0; x<32; x++) {
    sprintf(label, "%u", x);
    gtk_grid_attach(grid, gtk_label_new(label), x, 0, 1, 1);
  }

  /* set cell pointer to next empty grid cell */
  x=0;
  y=1;

  /* hardware type */
  sprintf(label, "Hardware Type: %u (%s)", htons(arp->ar_hrd), hardwaretype(htons(arp->ar_hrd)));
  append_field(grid, &x, &y, sizeof(arp->ar_hrd)*8, label, ARP_HTYPE);

  /* protocol type */
  sprintf(label, "Protocol Type: 0x%04x (%s)", htons(arp->ar_pro), ethertype(htons(arp->ar_pro)));
  append_field(grid, &x, &y, sizeof(arp->ar_pro)*8, label, ARP_PTYPE);

  /* hardware length */
  sprintf(label, "Hardware Length: %u", arp->ar_hln);
  append_field(grid, &x, &y, sizeof(arp->ar_hln)*8, label, ARP_HLEN);

  /* protocol length */
  sprintf(label, "Protocol Length: %u", arp->ar_pln);
  append_field(grid, &x, &y, sizeof(arp->ar_pln)*8, label, ARP_PLEN);

  /* operation */
  sprintf(label, "Operation: %u (%s)", htons(arp->ar_op), arp_operation(htons(arp->ar_op)));
  append_field(grid, &x, &y, sizeof(arp->ar_op)*8, label, ARP_OPERATION);

  /* sender hardware address (SHA) */
  sprintf(label, "Sender Hardware Address: %02x:%02x:%02x:%02x:%02x:%02x", options[0], options[1], options[2], options[3], options[4], options[5]);
  append_field(grid, &x, &y, 48, label, ARP_HW_SENDER);
  options += 6;

  /* sender protocol address (SPA) */
  sprintf(label, "Sender Protocol Address: %u.%u.%u.%u", options[0], options[1], options[2], options[3]);
  append_field(grid, &x, &y, 32, label, ARP_PROTO_SENDER);
  options += 4;

  /* sender hardware address (THA) */
  sprintf(label, "Target Hardware Address: %02x:%02x:%02x:%02x:%02x:%02x", options[0], options[1], options[2], options[3], options[4], options[5]);
  append_field(grid, &x, &y, 48, label, ARP_HW_TARGET);
  options += 6;

  /* sender protocol address (TPA) */
  sprintf(label, "Target Protocol Address: %u.%u.%u.%u", options[0], options[1], options[2], options[3]);
  append_field(grid, &x, &y, 32, label, ARP_PROTO_TARGET);
  options += 4;

  /* free memory of label */
  free(label);

  /* show ethernet grid (tab) */
  gtk_widget_show_all(GTK_WIDGET(grid));

  /* pass grid back to tab builder function */
  return(grid);
}

GtkGrid *icmp_grid(struct icmphdr *icmp, u_char *options, int left) {
  GtkGrid *grid;	/* the grid itself */
  char *label;		/* label of buttons to set */
  int x,y;			/* position pointer to next empty grid cell */
  int i;
  int optlen;
  char *optdata;

  /* init new empty grid */
  grid = GTK_GRID(gtk_grid_new());

  /* set columns to be uniform sized (for better bit size representation) */
  gtk_grid_set_column_homogeneous(grid, TRUE);

  /* allocate memory for button label */
  label = malloc(100);

  /* build bit indication topic line (0 1 2 .. 31) */
  for (x=0; x<32; x++) {
    sprintf(label, "%u", x);
    gtk_grid_attach(grid, gtk_label_new(label), x, 0, 1, 1);
  }

  /* set cell pointer to next empty grid cell */
  x=0;
  y=1;

  /* type */
  sprintf(label, "Type: %u (%s)", icmp->type, icmp_type(icmp->type));
  append_field(grid, &x, &y, sizeof(icmp->type)*8, label, ICMP_TYPE);

  /* code */
  sprintf(label, "Code: %u (%s)", icmp->code, icmp_code(icmp->type, icmp->code));
  append_field(grid, &x, &y, sizeof(icmp->code)*8, label, ICMP_CODE);

  /* checksum */
  sprintf(label, "Checksum: 0x%04x", htons(icmp->checksum));
  append_field(grid, &x, &y, sizeof(icmp->checksum)*8, label, ICMP_CHECKSUM);

  left -= 4;

  switch (icmp->type) {
    case 0: /* Echo */
    case 8: /* Echo Reply */
      sprintf(label, "Identifier: 0x%04x", htons(icmp->un.echo.id));
      append_field(grid, &x, &y, 8, label, ICMP_ECHO_ID);

      sprintf(label, "Sequence Number: 0x%04x", htons(icmp->un.echo.sequence));
      append_field(grid, &x, &y, 24, label, ICMP_ECHO_SEQUENCE);

      left -= 4;
      break;
    case 3: /* Destination Unreachable */
    case 4: /* Source Quench */
    case 11: /* Time Exceeded */
      /* unused */
      sprintf(label, "Unused: 0x%08x", htonl(icmp->un.gateway));
      append_field(grid, &x, &y, sizeof(icmp->un)*8, label, ICMP_UNUSED);
      left -= 4;

      /* Internet Header + 64 bits of Original Data Datagram */
      break;

    case 5: /* Redirect */
      sprintf(label, "Gateway Internet Address: %u.%u.%u.%u", icmp->un.gateway & 0xff, (icmp->un.gateway >> 8) & 0xff, (icmp->un.gateway >> 16) & 0xff, (icmp->un.gateway >> 24) & 0xff);
      append_field(grid, &x, &y, sizeof(icmp->un)*8, label, ICMP_REDIRECT_GATEWAY);
      left -= 4;
      break;

    case 12: /* Time exceeded */
      sprintf(label, "Pointer: 0x%02x", htonl(icmp->un.gateway & 0x000000ff));
      append_field(grid, &x, &y, 8, label, ICMP_TIME_POINTER);

      sprintf(label, "Unused: 0x%06x", htonl(icmp->un.gateway & 0xffffff00));
      append_field(grid, &x, &y, 24, label, ICMP_UNUSED);

      left -= 4;

      /* Internet Header + 64 bits of Original Data Datagram */
      break;

    case 13: /* Timestamp */
    case 14: /* Timestamp Reply */
      sprintf(label, "Identifier: 0x%04x", htons(icmp->un.echo.id));
      append_field(grid, &x, &y, 8, label, ICMP_ECHO_ID);

      sprintf(label, "Sequence Number: 0x%04x", htons(icmp->un.echo.sequence));
      append_field(grid, &x, &y, 24, label, ICMP_ECHO_SEQUENCE);

      left -= 4;

      /* Originate Timestamp */
      /* Receive Timestamp */
      /* Transmit Timestamp */
      break;

    case 15: /* information request message */
    case 16: /* information reply message */
      sprintf(label, "Identifier: 0x%04x", htons(icmp->un.echo.id));
      append_field(grid, &x, &y, 8, label, ICMP_ECHO_ID);

      sprintf(label, "Sequence Number: 0x%04x", htons(icmp->un.echo.sequence));
      append_field(grid, &x, &y, 24, label, ICMP_ECHO_SEQUENCE);

      left -= 4;

      /* no more data */
      break;
    default:
      /* unused */
      sprintf(label, "Unused: 0x%08x", htonl(icmp->un.gateway));
      append_field(grid, &x, &y, sizeof(icmp->un)*8, label, ICMP_UNUSED);
      left -= 4;
      break;
  }

  /* allocate memory for option data */
  optdata = malloc(10);

  /* progress bytes until no option bytes left */
  while (left > 0) {
    if (left >= 4) optlen = 4; else optlen = left;

    /* print bytes in hex format into array */
    for (i=0; i<optlen; ++i) sprintf(&optdata[i*2], "%02x", (unsigned int)options[i]);
    optdata[optlen*2] = 0x00;

    /* option data field */
    sprintf(label, "Data 0x%s", optdata);
    append_field(grid, &x, &y, optlen*8, label, ICMP_DATA);

    options += optlen;
    left -= optlen;
  }

  /* free data */
  free(optdata);

  /* free memory of label */
  free(label);

  /* show ethernet grid (tab) */
  gtk_widget_show_all(GTK_WIDGET(grid));

  /* pass grid back to tab builder function */
  return(grid);
}

GtkGrid *icmpv6_grid(struct icmp6_hdr *icmpv6, u_char *options, int left) {
  GtkGrid *grid;	/* the grid itself */
  char *label;		/* label of buttons to set */
  int x,y;			/* position pointer to next empty grid cell */
  int i;
  int opttype;
  int optlen;
  char *optdata;
  unsigned int ifield;
  unsigned short sfield;

  /* init new empty grid */
  grid = GTK_GRID(gtk_grid_new());

  /* set columns to be uniform sized (for better bit size representation) */
  gtk_grid_set_column_homogeneous(grid, TRUE);

  /* allocate memory for button label */
  label = malloc(100);

  /* build bit indication topic line (0 1 2 .. 31) */
  for (x=0; x<32; x++) {
    sprintf(label, "%u", x);
    gtk_grid_attach(grid, gtk_label_new(label), x, 0, 1, 1);
  }

  /* set cell pointer to next empty grid cell */
  x=0;
  y=1;

  /* type */
  sprintf(label, "Type: %u (%s)", icmpv6->icmp6_type, icmpv6_type(icmpv6->icmp6_type));
  append_field(grid, &x, &y, sizeof(icmpv6->icmp6_type)*8, label, ICMPV6_TYPE);

  /* code */
  sprintf(label, "Code: %u (%s)", icmpv6->icmp6_code, icmpv6_code(icmpv6->icmp6_type, icmpv6->icmp6_code));
  append_field(grid, &x, &y, sizeof(icmpv6->icmp6_code)*8, label, ICMPV6_CODE);

  /* checksum */
  sprintf(label, "Checksum: 0x%04x", htons(icmpv6->icmp6_cksum));
  append_field(grid, &x, &y, sizeof(icmpv6->icmp6_cksum)*8, label, ICMPV6_CHECKSUM);

  left -= 4;

  switch (icmpv6->icmp6_type) {
    case 133:
      memcpy(&ifield, options, 4);
      sprintf(label, "Reserved: 0x%08x", htonl(ifield));
      append_field(grid, &x, &y, 32, label, NDP_RS_RESERVED);
      options += 4;
      left -= 4;

      break;
    case 134:
      sprintf(label, "Cur Hop Limit: %u", options[0]);
      append_field(grid, &x, &y, 8, label, NDP_RA_CHLIMIT);
      options++;
      left--;

      /* Managed address configuration */
      if (options[0] & 0x80) {
        append_field(grid, &x, &y, 1, "M", NDP_RA_MACONFIG);
      } else {
        append_field(grid, &x, &y, 1, "m", NDP_RA_MACONFIG);
      }

      /* other address configuration */
      if (options[0] & 0x40) {
        append_field(grid, &x, &y, 1, "O", NDP_RA_OCONFIG);
      } else {
        append_field(grid, &x, &y, 1, "o", NDP_RA_OCONFIG);
      }

      sprintf(label, "Reserved: 0x%02x", options[0] & 0x3F);
      append_field(grid, &x, &y, 6, label, NDP_RA_RESERVED);
      options++;
      left--;

      memcpy(&sfield, options, 2);
      sprintf(label, "Router Lifetime: %u", htons(sfield));
      append_field(grid, &x, &y, 16, label, NDP_RA_ROUTERLIFETIME);
      options += 2;
      left -= 2;

      memcpy(&ifield, options, 4);
      sprintf(label, "Reachable Time: %u", htonl(ifield));
      append_field(grid, &x, &y, 32, label, NDP_RA_REACHTIME);
      options += 4;
      left -= 4;

      memcpy(&ifield, options, 4);
      sprintf(label, "Retrans Timer: %u", htonl(ifield));
      append_field(grid, &x, &y, 32, label, NDP_RA_RETRANSTIMER);
      options += 4;
      left -= 4;

      break;
    case 135:
      memcpy(&ifield, options, 4);
      sprintf(label, "Reserved: 0x%08x", htonl(ifield));
      append_field(grid, &x, &y, 32, label, NDP_NS_RESERVED);
      options += 4;
      left -= 4;

      sprintf(label, "Target Address: %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x", options[0], options[1], options[2], options[3], options[4], options[5], options[6], options[7], options[8], options[9], options[10], options[11], options[12], options[13], options[14], options[15]);
      append_field(grid, &x, &y, 128, label, NDP_NS_TARGET);
      options += 16;
      left -= 16;

      break;
    case 136:
      memcpy(&ifield, options, 4);
      ifield = htonl(ifield);

      /* router flag */
      if (ifield & 0x80000000) {
        append_field(grid, &x, &y, 1, "R", NDP_NA_ROUTER);
      } else {
        append_field(grid, &x, &y, 1, "r", NDP_NA_ROUTER);
      }

      /* solicited flag */
      if (ifield & 0x40000000) {
        append_field(grid, &x, &y, 1, "S", NDP_NA_SOLICITED);
      } else {
        append_field(grid, &x, &y, 1, "s", NDP_NA_SOLICITED);
      }

      /* override flag */
      if (ifield & 0x20000000) {
        append_field(grid, &x, &y, 1, "O", NDP_NA_OVERRIDE);
      } else {
        append_field(grid, &x, &y, 1, "o", NDP_NA_OVERRIDE);
      }

      sprintf(label, "Reserved: 0x%08x", ifield & 0x1FFFFFFF);
      append_field(grid, &x, &y, 29, label, NDP_NA_RESERVED);
      options += 4;
      left -= 4;

      sprintf(label, "Target Address: %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x", options[0], options[1], options[2], options[3], options[4], options[5], options[6], options[7], options[8], options[9], options[10], options[11], options[12], options[13], options[14], options[15]);
      append_field(grid, &x, &y, 8*8, label, NDP_NA_TARGET);
      options += 16;
      left -= 16;

      break;
    case 137:
      memcpy(&ifield, options, 4);
      sprintf(label, "Reserved: 0x%08x", htonl(ifield));
      append_field(grid, &x, &y, 32, label, NDP_R_RESERVED);
      options += 4;
      left -= 4;

      sprintf(label, "Target Address: %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x", options[0], options[1], options[2], options[3], options[4], options[5], options[6], options[7], options[8], options[9], options[10], options[11], options[12], options[13], options[14], options[15]);
      append_field(grid, &x, &y, 128, label, NDP_R_TARGET);
      options += 16;
      left -= 16;

      sprintf(label, "Destination Address: %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x", options[0], options[1], options[2], options[3], options[4], options[5], options[6], options[7], options[8], options[9], options[10], options[11], options[12], options[13], options[14], options[15]);
      append_field(grid, &x, &y, 128, label, NDP_R_DEST);
      options += 16;
      left -= 16;

      break;
  }

  /* NDP options */
  if ((icmpv6->icmp6_type >= 133) && (icmpv6->icmp6_type <= 137)) {
    while (left > 0) {
      opttype = options[0];
      sprintf(label, "Type: %u (%s)", opttype, icmpv6_opttype(opttype));
      append_field(grid, &x, &y, 8, label, NDP_OPTION_TYPE);

      optlen = options[1] * 8;
      sprintf(label, "Length: %u (%u bytes)", options[1], optlen);
      append_field(grid, &x, &y, 8, label, NDP_OPTION_LENGTH);

      optdata = malloc(optlen*3);

      switch (opttype) {
        case 1:
          for (i=0; i<optlen-2; ++i) sprintf(&optdata[i*3], "%02x:", (unsigned int)options[i+2]);
          optdata[(optlen-2)*3-1] = 0x00;

          sprintf(label, "Source Link-layer Address: %s", optdata);
          append_field(grid, &x, &y, (optlen-2)*8, label, NDP_OPTION_SOURCELLA);

          break;
        case 2:
          for (i=0; i<optlen-2; ++i) sprintf(&optdata[i*3], "%02x:", (unsigned int)options[i+2]);
          optdata[(optlen-2)*3-1] = 0x00;

          sprintf(label, "Target Link-layer Address: %s", optdata);
          append_field(grid, &x, &y, (optlen-2)*8, label, NDP_OPTION_TARGETLLA);

          break;
        case 3:
          sprintf(label, "Prefix Length: %u", options[3]);
          append_field(grid, &x, &y, 8, label, NDP_OPTION_PREFLEN);

          /* link determination */
          if (options[4] & 0x80) {
            append_field(grid, &x, &y, 1, "L", NDP_OPTION_PREFLINK);
          } else {
            append_field(grid, &x, &y, 1, "l", NDP_OPTION_PREFLINK);
          }

          /* autonomous address-configuration */
          if (options[4] & 0x40) {
            append_field(grid, &x, &y, 1, "A", NDP_OPTION_PREFAUTO);
          } else {
            append_field(grid, &x, &y, 1, "a", NDP_OPTION_PREFAUTO);
          }

          sprintf(label, "Reserved: 0x%02x", options[4] & 0x3F);
          append_field(grid, &x, &y, 6, label, NDP_OPTION_PREFRES);

          memcpy(&ifield, options+4, 4);
          sprintf(label, "Valid Lifetime: 0x%08x (%u)", htonl(ifield), htonl(ifield));
          append_field(grid, &x, &y, 32, label, NDP_OPTION_PREFVLT);

          memcpy(&ifield, options+8, 4);
          sprintf(label, "Preferred Lifetime: 0x%08x (%u)", htonl(ifield), htonl(ifield));
          append_field(grid, &x, &y, 32, label, NDP_OPTION_PREFPLT);

          memcpy(&ifield, options+12, 4);
          sprintf(label, "Reserved: 0x%08x", htonl(ifield));
          append_field(grid, &x, &y, 32, label, NDP_OPTION_PREFRES);

          sprintf(label, "Prefix: %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x", options[16], options[17], options[18], options[19], options[20], options[21], options[22], options[23], options[24], options[25], options[26], options[27], options[28], options[29], options[30], options[31]);
          append_field(grid, &x, &y, 128, label, NDP_OPTION_PREFIX);

          break;
        case 4:
          sprintf(label, "Reserved: 0x%02x%02x%02x%02x%02x%02x", options[2], options[3], options[4], options[5], options[6], options[7]);
          append_field(grid, &x, &y, 48, label, NDP_OPTION_RHRES);

          for (i=0; i<optlen-8; ++i) sprintf(&optdata[i*2], "%02x", (unsigned int)options[i+8]);
          optdata[(optlen-8)*2] = 0x00;

          sprintf(label, "IP Header + Data: 0x%s", optdata);
          append_field(grid, &x, &y, optlen*8, label, NDP_OPTION_RHDATA);

          break;
        case 5:
          memcpy(&sfield, options+2, 2);
          sprintf(label, "Reserved: 0x%04x", htons(sfield));
          append_field(grid, &x, &y, 16, label, NDP_OPTION_MTURES);

          memcpy(&ifield, options+4, 4);
          sprintf(label, "MTU: %u", htonl(ifield));
          append_field(grid, &x, &y, 32, label, NDP_OPTION_MTU);

          break;
      }

      free(optdata);

      options += optlen;
      left -= optlen;
    }
  }

  /* free memory of label */
  free(label);

  /* show ethernet grid (tab) */
  gtk_widget_show_all(GTK_WIDGET(grid));

  /* pass grid back to tab builder function */
  return(grid);
}