Wireshark · Ethereal-dev: [Ethereal-dev] Re: [PATCH] Changes to PPP protocol

[Burke Lau <burke_lau@xxxxxxxxxxx>]

Woops!
  There was a problem in one of the patch files, I diffed the
packet-mpls.c with the packet-ip.c file by accident.

Here's the correct set of patches.

Burke.

Burke Lau wrote:
> 
>   I've made some changes to the ethereal PPP protocol decodes and
> thought they would be useful to include back in the main CVS source
> tree.
> 
>   Attached are the patch files to add/modify the PPP protocol to have
> the following features:
> * FCS 32 and FCS 16 Checking of the ppp packets, selectable in the
> Preferences dialog
> * PPP can handle the CISCO HDLC format
> * MPLS decode over PPP support has also been added.
> 
> I'm behind a firewall so I've been working with the 0.8.14 version and
> had to do a diff with the version 0.8.14
> 
> Burke.
> 
-- 
Burke Lau                             Email: burke_lau@xxxxxxxxxxx
Advanced Networks Division            Voice: +61 3 9210-5533
Agilent Technologies                  Fax  : +61 3 9210-5550
347 Burwood Hwy.                      WWW  : http://www.agilent.com
Forest Hill, Vic, 3131, Australia

--- packet-mpls.c	Mon Nov 20 15:36:12 2000
+++ ../changed/packet-mpls.c	Wed Dec 13 21:02:48 2000
@@ -45,6 +45,9 @@
 #include <glib.h>
 #include "etypes.h"
 #include "packet.h"
+#include "packet-ip.h"
+#include "ppptypes.h"
+#include "packet-ppp.h"
 
 static gint proto_mpls = -1;
 
@@ -197,6 +200,7 @@
 proto_reg_handoff_mpls(void)
 {
 	old_dissector_add("ethertype", ETHERTYPE_MPLS, dissect_mpls);
+	old_dissector_add("ppp.protocol", PPP_MPLS_UNI, dissect_mpls);
 
 	/*
 	 * Get a handle for the IP dissector.

--- packet-ppp.c	Mon Nov 20 15:36:14 2000
+++ ../changed/packet-ppp.c	Thu Dec 14 11:56:23 2000
@@ -33,6 +33,7 @@
 #endif
 
 #include <glib.h>
+#include "prefs.h"
 #include "packet.h"
 #include "packet-ppp.h"
 #include "ppptypes.h"
@@ -72,6 +73,12 @@
 static int ett_mp = -1;
 static int ett_mp_flags = -1;
 
+/* options */
+static gint ppp_fcs_decode = 0; /* 0 = No FCS, 1 = 16 bit FCS, 2 = 32 bit FCS */
+#define NO_FCS 0
+#define FCS_16 1
+#define FCS_32 2
+
 /* PPP structs and definitions */
 
 typedef struct _e_ppphdr {
@@ -99,6 +106,10 @@
 	{PPP_LQR,	"Link Quality Report protocol" },
 	{PPP_CHAP,	"Cryptographic Handshake Auth. Protocol" },
 	{PPP_CBCP,	"Callback Control Protocol" },
+	{PPP_MPLS_UNI, "MPLS Uni-cast"},
+	{PPP_MPLS_MULTI, "MPLS Multi-cast"},
+	{CISCO_IP, "CISCO HDLC IP"},
+	{CISCO_SLARP, "CISCO HDLC SLARP"},
 	{0,             NULL            }
 };
 
@@ -501,10 +512,161 @@
 
 #define N_IPCP_OPTS	(sizeof ipcp_opts / sizeof ipcp_opts[0])
 
+const unsigned int fcstab_32[256] =
+      {
+      0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
+      0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+      0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+      0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+      0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+      0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+      0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
+      0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+      0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+      0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+      0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
+      0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+      0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
+      0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+      0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+      0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+      0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
+      0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+      0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
+      0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+      0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+      0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+      0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
+      0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+      0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+      0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+      0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+      0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+      0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
+      0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+      0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
+      0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+      0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+      0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+      0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+      0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+      0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
+      0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+      0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+      0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+      0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
+      0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+      0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
+      0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+      0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+      0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+      0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
+      0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+      0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
+      0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+      0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+      0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+      0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
+      0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+      0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+      0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+      0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+      0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+      0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
+      0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+      0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
+      0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+      0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+      0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+      };
+
+const unsigned short fcstab_16[256] = {
+        0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+        0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+        0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+        0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+        0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+        0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+        0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+        0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+        0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+        0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+        0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+        0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+        0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+        0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+        0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+        0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+        0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+        0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+        0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+        0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+        0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+        0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+        0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+        0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+        0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+        0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+        0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+        0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+        0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+        0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+        0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+        0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+    };
+  
+/*
+*******************************************************************************
+* DETAILS : Calculate a new FCS-16 given the current FCS-16 and the new data.
+*******************************************************************************
+*/
+guint16
+fcs16(register guint16 fcs,
+         tvbuff_t * tvbuff,
+         guint32 offset,
+         guint32 len)
+{
+    guint8 val;
+    /* Check for Invalid Length */
+    if(len == 0)
+        return(0x0000);
+    while (len--) {
+		val = tvb_get_guint8(tvbuff, offset++);
+		fcs = (guint16)((fcs >> 8) & 0x00ff) ^
+            fcstab_16[((guint16)(fcs ^ (guint16)((val) & 0x00ff)) & 0x00ff)];
+	}
+
+    return (fcs ^ 0xffff);
+}
+  
+/*
+*******************************************************************************
+* DETAILS : Calculate a new FCS-32 given the current FCS-32 and the new data.
+*******************************************************************************
+*/
+guint32
+fcs32(guint32 fcs,
+         tvbuff_t * tvbuff,
+         guint32 offset,
+         guint32 len)
+{
+    guint8 val;
+    /* Check for invalid Length */
+    if(len <= 0)
+        return(0x00000000);
+
+    while (len--) {
+		val = tvb_get_guint8(tvbuff, offset++);
+		fcs = (((fcs) >> 8) ^ fcstab_32[((fcs) ^ (val)) & 0xff]);
+	}
+    return (fcs ^ 0xffffffff);
+}
+
 void
 capture_ppp( const u_char *pd, int offset, packet_counts *ld ) {
   switch (pntohs(&pd[offset + 2])) {
     case PPP_IP:
+    case CISCO_IP:
       capture_ip(pd, offset + 4, ld);
       break;
     case PPP_IPX:
@@ -1116,6 +1278,8 @@
   int        proto_offset;
   tvbuff_t   *next_tvb;
   guint8     byte0;
+  guint32    rx_fcs_exp;
+  guint32    rx_fcs_got;
 
   CHECK_DISPLAY_AS_DATA(proto_ppp, tvb, pinfo, tree);
 
@@ -1128,6 +1292,13 @@
     ph.ppp_prot = tvb_get_ntohs(tvb, 2);
     proto_offset =  2;
   }
+  /* Cisco HDLC format */
+  else if (byte0 == 0x0f) {
+    ph.ppp_addr = tvb_get_guint8(tvb, 0);
+    ph.ppp_ctl  = tvb_get_guint8(tvb, 1);
+    ph.ppp_prot = tvb_get_ntohs(tvb, 2);
+    proto_offset =  2;
+  }
   else {
     /* address and control are compressed (NULL) */
     ph.ppp_prot = tvb_get_ntohs(tvb, 0);
@@ -1151,6 +1322,10 @@
       proto_tree_add_text(fh_tree, tvb, 0, 1, "Address: %02x", ph.ppp_addr);
       proto_tree_add_text(fh_tree, tvb, 1, 1, "Control: %02x", ph.ppp_ctl);
     }
+    else if (byte0 == 0x0f) {
+      proto_tree_add_text(fh_tree, tvb, 0, 1, "Address: %02x", ph.ppp_addr);
+      proto_tree_add_text(fh_tree, tvb, 1, 1, "Control: %02x", ph.ppp_ctl);
+    }
   }
 
   next_tvb = tvb_new_subset(tvb, proto_offset, -1, -1);
@@ -1159,6 +1334,35 @@
     if (check_col(pinfo->fd, COL_PROTOCOL))
       col_add_fstr(pinfo->fd, COL_PROTOCOL, "0x%04x", ph.ppp_prot);
   }
+
+  /* Calculate the FCS check */
+  if (ppp_fcs_decode == FCS_16) {
+    rx_fcs_got = 0;
+    rx_fcs_exp = fcs16(0xFFFF, tvb, 0, tvb_length(tvb) - 2);
+    rx_fcs_got = tvb_get_guint8(tvb, tvb_length(tvb) - 2) |
+        (tvb_get_guint8(tvb, tvb_length(tvb) - 1) << 8);
+  	if (rx_fcs_got != rx_fcs_exp) {
+      proto_tree_add_text(fh_tree, tvb, tvb_length(tvb) - 2, 2, "FCS 16: %04x (incorrect, expect %04x)", rx_fcs_got, rx_fcs_exp);
+  	}
+  	else {
+      proto_tree_add_text(fh_tree, tvb, tvb_length(tvb) - 2, 2, "FCS 16: %04x (correct)", rx_fcs_got);
+  	}
+  }
+  else if(ppp_fcs_decode == FCS_32) {
+    rx_fcs_got = 0;
+    rx_fcs_exp = fcs32(0xFFFFFFFF, tvb, 0, tvb_length(tvb) - 4);
+    rx_fcs_got = tvb_get_guint8(tvb, tvb_length(tvb) - 4) |
+        (tvb_get_guint8(tvb, tvb_length(tvb) - 3) << 8) |
+        (tvb_get_guint8(tvb, tvb_length(tvb) - 2) << 16) | 
+        (tvb_get_guint8(tvb, tvb_length(tvb) - 1) << 24);
+  	if (rx_fcs_got != rx_fcs_exp) {
+      proto_tree_add_text(fh_tree, tvb, tvb_length(tvb) - 4, 4, "FCS 32: %08x (incorrect, expect %08x) ", rx_fcs_got, rx_fcs_exp);
+  	}
+  	else {
+      proto_tree_add_text(fh_tree, tvb, tvb_length(tvb) - 4, 4, "FCS 32: %08x (correct)", rx_fcs_got);
+  	}
+  }
+
 }
 
 void
@@ -1188,6 +1392,15 @@
 		&ett_lcp_internationalization_opt,
 	};
 
+    static enum_val_t ppp_options[] = {
+    	{"None", 0}, 
+    	{"16-Bit", 1}, 
+    	{"32-Bit", 2},
+    	{NULL, -1}
+    };
+    
+    module_t *ppp_module;
+
         proto_ppp = proto_register_protocol("Point-to-Point Protocol", "ppp");
  /*       proto_register_field_array(proto_ppp, hf, array_length(hf));*/
 	proto_register_subtree_array(ett, array_length(ett));
@@ -1197,6 +1410,16 @@
 
 	register_dissector("ppp", dissect_ppp);
 	register_dissector("payload_ppp", dissect_payload_ppp);
+
+	/* Register the preferences for the ppp protocol */
+	ppp_module = prefs_register_module("ppp", "PPP", NULL);
+
+	prefs_register_enum_preference(ppp_module, 
+	"ppp_fcs",
+	"PPP Frame Checksum",
+    "PPP Frame Checksum", 
+    &ppp_fcs_decode,
+    ppp_options, FALSE);
 }
 
 void

--- ppptypes.h	Mon Apr 17 06:37:08 2000
+++ ../changed/ppptypes.h	Thu Dec 14 11:43:41 2000
@@ -40,6 +40,8 @@
 #define PPP_MP		0x3d	/* Multilink PPP */
 #define PPP_IPV6	0x57	/* Internet Protocol Version 6 */
 #define PPP_COMP	0xfd	/* compressed packet */
+#define PPP_MPLS_UNI   0x281 /* MPLS Unicast */
+#define PPP_MPLS_MULTI 0x281 /* MPLS Multicast */
 #define PPP_IPCP	0x8021	/* IP Control Protocol */
 #define PPP_ATCP	0x8029	/* AppleTalk Control Protocol */
 #define PPP_IPXCP	0x802b	/* IPX Control Protocol */
@@ -49,5 +51,13 @@
 #define PPP_LQR		0xc025	/* Link Quality Report protocol */
 #define PPP_CHAP	0xc223	/* Cryptographic Handshake Auth. Protocol */
 #define PPP_CBCP	0xc029	/* Callback Control Protocol */
+
+/* Protocol types for the CISCO HDLC Format */
+#define CISCO_IP	0x0800	/* Internet Protocol */
+#define CISCO_SLARP	0x8035	/* CISCO SLARP protocol */
+
+/* Address and control field for CISCO HDLC */
+#define CISCO_HDLC_ADDR_CTRL	0x0F00	/* Internet Protocol */
+
 
 #endif /* ppptypes.h */

--- packet-ip.c	Mon Nov 20 15:36:10 2000
+++ ../changed/packet-ip.c	Thu Dec 14 11:56:00 2000
@@ -1477,6 +1477,7 @@
 {
 	dissector_add("ethertype", ETHERTYPE_IP, dissect_ip);
 	dissector_add("ppp.protocol", PPP_IP, dissect_ip);
+	dissector_add("ppp.protocol", CISCO_IP, dissect_ip);
 	dissector_add("llc.dsap", SAP_IP, dissect_ip);
 	dissector_add("ip.proto", IP_PROTO_IPV4, dissect_ip);
 	dissector_add("ip.proto", IP_PROTO_IPIP, dissect_ip);