From Francois-Xavier Le Bail:

The following patch decodes DHCP option 121. (RFC 3442)

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@22399 f5534014-38df-0310-8fa8-9805f1628bb7

diff --git a/epan/dissectors/packet-bootp.c b/epan/dissectors/packet-bootp.c
index d47a422a6a95561434876c9c7dfdacdb3db2a8d9..6b7224d8033ed9da72dd3efb87be89e88c1ff02e 100644 (file)
--- a/epan/dissectors/packet-bootp.c
+++ b/epan/dissectors/packet-bootp.c
@@ -20,6 +20,7 @@
  * RFC 3203: DHCP reconfigure extension
  * RFC 3495: DHCP Option (122) for CableLabs Client Configuration
  * RFC 3594: PacketCable Security Ticket Control Sub-Option (122.9)
+ * RFC 3442: Classless Static Route Option for DHCP version 4
  * draft-ietf-dhc-fqdn-option-07.txt
  * BOOTP and DHCP Parameters
  *     http://www.iana.org/assignments/bootp-dhcp-parameters
@@ -428,7 +429,7 @@ static struct opt_info bootp_opt[] = {
 /* 118 */ { "Subnet Selection Option",                 ipv4_list, NULL },
 /* 119 */ { "Domain Search",                           opaque, NULL },
 /* 120 */ { "SIP Servers",                             opaque, NULL },
-/* 121 */ { "Classless Static Route",                  opaque, NULL },
+/* 121 */ { "Classless Static Route",                  special, NULL },
 /* 122 */ { "CableLabs Client Configuration",          opaque, NULL },
 /* 123 */ { "Unassigned",                              opaque, NULL },
 /* 124 */ { "V-I Vendor Class",                                opaque, NULL },
@@ -1228,6 +1229,55 @@ bootp_option(tvbuff_t *tvb, proto_tree *bp_tree, int voff, int eoff,
                }
                break;
 
+       case 121: {     /* Classless Static Route */
+               int mask_width, significant_octets;
+               optend = optoff + optlen;
+               /* minimum length is 5 bytes */
+               if (optlen < 5) {
+                       proto_item_append_text(vti, " [ERROR: Option length < 5 bytes]");
+                       break;
+               }
+               while (optoff < optend) {
+                       mask_width = tvb_get_guint8(tvb, optoff);
+                       /* mask_width <= 32 */
+                       if (mask_width > 32) {
+                               proto_tree_add_text(v_tree, tvb, optoff,
+                                       optend - optoff,
+                                       "Subnet/MaskWidth-Router: [ERROR: Mask width (%d) > 32]",
+                                       mask_width);
+                               break;
+                       }
+                       significant_octets = (mask_width + 7) / 8;
+                       vti = proto_tree_add_text(v_tree, tvb, optoff,
+                               1 + significant_octets + 4,
+                               "Subnet/MaskWidth-Router: ");
+                       optoff++;
+                       /* significant octets + router(4) */
+                       if (optend < optoff + significant_octets + 4) {
+                               proto_item_append_text(vti, "[ERROR: Remaining length (%d) < %d bytes]",
+                                       optend - optoff, significant_octets + 4);
+                               break;
+                       }
+                       if(mask_width == 0)
+                               proto_item_append_text(vti, "default");
+                       else {
+                               for(i = 0 ; i < significant_octets ; i++) {
+                                       if (i > 0)
+                                               proto_item_append_text(vti, ".");
+                                       byte = tvb_get_guint8(tvb, optoff++);
+                                       proto_item_append_text(vti, "%d", byte);
+                               }
+                               for(i = significant_octets ; i < 4 ; i++)
+                                       proto_item_append_text(vti, ".0");
+                               proto_item_append_text(vti, "/%d", mask_width);
+                       }
+                       proto_item_append_text(vti, "-%s",
+                           ip_to_str(tvb_get_ptr(tvb, optoff, 4)));
+                       optoff += 4;
+               }
+               break;
+       }
+
        case 125: {     /* V-I Vendor-specific Information */
                int enterprise = 0;
                int s_end = 0;