Updating to the latest LBL release.

Sun's SKIP support added.

1 files changed, 919 insertions, 0 deletions

diff --git a/usr.sbin/tcpdump/print-skip.c b/usr.sbin/tcpdump/print-skip.c
new file mode 100644
index 00000000000..74db84676bc
--- /dev/null
+++ b/usr.sbin/tcpdump/print-skip.c
@@ -0,0 +1,919 @@
+/*	$OpenBSD: print-skip.c,v 1.1 1996/03/04 15:59:35 mickey Exp $	*/
+/*
+ * Copyright (c) 1995 Sun Microsystems, Inc.
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+
+ * IN NO EVENT SHALL SUN MICROSYSTEMS, INC. BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
+ * SUN MICROSYSTEMS, INC. HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+
+ * SUN MICROSYSTEMS, INC. SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+ * THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND SUN
+ * MICROSYSTEMS, INC. HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
+ * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+*/
+
+#include <sys/param.h> 
+#include <sys/time.h> 
+#include <sys/types.h>
+ 
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/ip_var.h>
+#include <netinet/tcp.h>
+#include <netinet/tcpip.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "interface.h"
+#include "addrtoname.h"
+
+#define MAX_ALGS		(256)
+
+extern int skipflag;
+
+const int       skip_max_algs = MAX_ALGS;
+
+char            *old_skip_crypt_algs[MAX_ALGS] = {
+                                        "none",         /* 0 */
+                                        "des_cbc",      /* 1 */
+                                        "rc2_cbc",      /* 2 */
+                                        "rc4(40bit)",   /* 3 */
+                                        "rc4(128bit)",  /* 4 */
+                                        "des_ede-2",    /* 5 */
+                                        "des_ede-3",    /* 6 */
+                                        "idea",         /* 7 */
+                                        "",             /* 8 */
+                                        "",             /* 9 */
+                                        "simplecrypt"   /* 10 */
+                };
+
+
+char *
+skip_alg_to_name(char *table[], int alg)
+{
+        if (alg > skip_max_algs) {
+                return ("<invalid>");
+        }
+        if (alg < 0) {
+                return ("<invalid>");
+        }
+        if (table[alg] == NULL) {
+                return ("<unknown>");
+        }
+        if (strlen(table[alg]) == 0) {
+                return ("<unknown>");
+        }
+        return (table[alg]);
+}
+
+/*
+ * This is what an OLD skip encrypted-authenticated packet looks like:
+ *
+ *
+ *                 0       1      2      3
+ *            ---------------------------------
+ *            |                               |
+ *            /      Clear IP Header          /  
+ *            |                               |     IP protocol = IPSP
+ *            ---------------------------------
+ *            |                               |
+ *            |         IPSP header           |  
+ *            |                               |
+ *            ---------------------------------
+ *            |                               |
+ *            /    Protected  IPSP Payload    /
+ *            /                               /
+ *            |                               |
+ *            ---------------------------------
+ *
+ *
+ * The format of the IPSP header for encrypted-encapsulated mode is shown below. * The fields are transmitted from left to right.
+ *
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  | Ver.  |E|A|C|S|B|R|               zero                        |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |    Kij alg.   |   Kp alg.     |        reserved               |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |    Optional boxid field                                       |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |    Kp encrypted in Kij...          (typically 8-16 bytes)
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |    Message Indicator (e.g IV)...   (typically 8-16 bytes)
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |    Protected IPSP Payload...
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ *
+ *   Field values:
+ *   Ver.: protocol version
+ *   E:    1 if packet is encrypted, 0 otherwise
+ *   A:    1 if packet is authenticated, 0 otherwise
+ *   C:    1 if packet is compressed before encryption, 0 otherwise
+ *   S:    1 if packet is sequenced, 0 otherwise
+ *   B:    1 if packet is tunneled (header contains boxid), 0 otherwise
+ *   R:    reserved (should be 0 until specified)
+ *
+ */
+/*
+ * per-algorithm encrytped key sizes...
+ */
+unsigned char   old_skip_ekp_sizes[MAX_ALGS] = {
+                          8,    /* plaintext */
+                          8,    /* DES */
+                          8,    /* RC2 */
+                          8,    /* RC4 (40 bit)  */
+                         16,    /* RC4 (128 bit) */
+                         16,    /* 3DES 2 */
+                         24,    /* 3DES 3 */
+                         16,    /* IDEA */
+                          0,    /* */
+                          0,    /* */
+                          8,    /* simplecrypt */
+                };
+/*
+ * per-algorithm message indicator sizes...
+ */
+unsigned char   old_skip_mid_sizes[MAX_ALGS] = {
+                          8,    /* plaintext */
+                          8,    /* DES */
+                          8,    /* RC2 */
+                          8,    /* RC4 40 bit */
+                          8,    /* RC4 128 bit */
+                          8,    /* 3DES 2 */
+                          8,    /* 3DES 3 */
+                          8,    /* IDEA */
+                          0,    /* */
+                          0,    /* */
+                          8,    /* simplecrypt */
+                };
+
+void skip_print_old(register const u_char *bp, register int length, 
+							const u_char *bp2)
+{
+	struct ip *ip;
+	const u_char *end;
+	u_char *p;
+	unsigned char	kij_alg, kp_alg, *c;
+	unsigned short i;
+	unsigned short len;
+	int boxid;
+	int node;
+
+	ip=(struct ip *)bp2;
+	p=(u_char *)bp;
+	end=bp+length;
+	printf("SKIP: *** OLD SKIP ***\n");
+	printf("OSKIP: %s>%s:%d",ipaddr_string(&ip->ip_src),
+			       ipaddr_string(&ip->ip_dst),length);
+	if (!skipflag)
+		return;
+	printf("\nOSKIP: SAID byte 1= 0x%02x\n",*p);
+	printf("OSKIP:    xxxx .... = version %d\n", (int) (*p & 0xf0) >> 4);
+        if (*p & 0x08) {
+                printf("OSKIP:    .... 1... = encrypted\n");
+        } else {
+                printf("OSKIP:    .... 0... = not encrypted\n");
+        }
+ 
+        if (*p & 0x04) {
+                printf("OSKIP:    .... .1.. = authenticated\n");
+        } else {
+                printf("OSKIP:    .... .0.. = not authenticated\n");
+        }
+ 
+        if (*p & 0x02) {
+                printf("OSKIP:    .... ..1. = compressed\n");
+        } else {
+                printf("OSKIP:    .... ..0. = not compressed\n");
+        }
+ 
+        if (*p & 0x01) {
+                printf("OSKIP:    .... ...1 = sequenced\n");
+        } else {
+                printf("OSKIP:    .... ...0 = not sequenced\n");
+        }
+                           
+        p++;
+
+  	printf("OSKIP: SAID byte 2 = 0x%02x\n", *p);
+ 
+        if (*p & 0x80) {
+		node=1;
+                printf("OSKIP:    1... .... = Node ID present\n");
+        } else {
+		node=0;
+                printf("OSKIP:    0... .... = no Node ID present\n");
+        }
+ 
+        if (*p & 0x40) {
+                printf("OSKIP:    .1.. .... = <reserved should be zero>\n");
+        } else {
+                printf("OSKIP:    .0.. .... = <reserved should be zero>\n");
+        }
+ 
+        if (*p & 0x20) {
+                printf("OSKIP:    ..1. .... = <reserved should be zero>\n");
+        } else {
+                printf("OSKIP:    ..0. .... = <reserved should be zero>\n");
+        }
+ 
+        if (*p & 0x10) {
+                printf("OSKIP:    ...1 .... = <reserved should be zero>\n");
+        } else {
+                printf("OSKIP:    ...0 .... = <reserved should be zero>\n");
+        }
+	  p++;
+        printf("OSKIP: SAID byte 3 = 0x%02x\n", *p);
+ 
+        p++;     
+        printf("OSKIP: SAID byte 4 = 0x%02x\n", *p);
+ 
+        p++;
+ 
+        kij_alg = *p;
+        printf("OSKIP: Kij alg (key encryption algorithm) = 0x%02x (%s)\n",
+		    kij_alg, skip_alg_to_name(old_skip_crypt_algs,kij_alg));
+ 
+        p++;
+ 
+        kp_alg = *p;
+        printf("OSKIP: Kp alg (traffic encryption algorithm) = 0x%02x (%s)\n",
+		    kp_alg, skip_alg_to_name(old_skip_crypt_algs,kp_alg));
+ 
+        p++;
+ 
+        /*
+         * the skip reserved field
+         */
+        printf("OSKIP: reserved byte 1 = 0x%02x\n", *p++);
+        printf("OSKIP: reserved byte 2 = 0x%02x\n", *p++);
+
+        if (node) {
+        /*
+         * boxid field
+         */
+	    if ((end - p) < sizeof(boxid)) {
+		    return;
+	    }
+	    c = (unsigned char *) &boxid;
+	    *c++ = *p++;
+	    *c++ = *p++;
+	    *c++ = *p++;
+	    *c++ = *p++;
+
+	    printf("OSKIP: Node ID = 0x%08x\n", ntohl(boxid));
+        }
+
+        /*
+         * encrypted kp (ekp) field
+         */
+
+        /*
+         * do this with a for-loop to avoid alignment problems and the
+         * overhead of calling bcopy()
+         */
+        len     = old_skip_ekp_sizes[kp_alg];
+        if ((unsigned short) (end - p) < len) {
+                return;
+        }
+
+        printf("OSKIP: encrypted Kp:  ");
+        for (i = 0; i < len; i++) {
+                printf("%02x ", (unsigned char) *p++);
+        }
+        printf("\n");
+
+        /*
+         * message indicator (mid) field
+         */
+        len     = old_skip_mid_sizes[kp_alg];
+        if ((unsigned short) (end - p) < len) {
+                return;
+        }
+        printf("OSKIP: message indicator field:  ");
+        for (i = 0; i < len; i++) {
+                printf("%02x ", (unsigned char) *p++);
+        }
+        printf("\n");
+}
+
+
+
+/* 
+ * The following part is (c) by G. Caronni  -- 29.11.95 
+ *
+ * This code is in the public domain; do with it what you wish.
+ *
+ * NO WARRANTY, NO SUPPORT, NO NOTHING!
+ */
+
+
+/*
+ * This is what a NEW skip encrypted-authenticated packet looks like:
+ *
+ *
+ *                 0       1      2      3
+ *            ---------------------------------
+ *            |                               |
+ *            /      Clear IP Header          /  
+ *            |                               |     IP protocol = SKIP
+ *            ---------------------------------
+ *            |                               |
+ *            |         SKIP header           |  
+ *            |                               |
+ *            ---------------------------------
+ *            |                               |
+ *            |    Auth Header & payload      |  
+ *            |                               |
+ *            ---------------------------------
+ *            |                               |
+ *            |    ESP header and SPI         |  
+ *            |                               |
+ *            ---------------------------------
+ *            |                               |
+ *            /    Protected  ESP Payload     /
+ *            |                               |
+ *            ---------------------------------
+ *
+ *
+ * The format of the SKIP header for encrypted-encapsulated mode is shown below. * The fields are transmitted from left to right.
+ *
+ *    0                   1                   2                   3
+ *    0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *   |  Ver  | Rsvd  | Source NSID   | Dest NSID     | NEXT HEADER   |
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *   |                    Counter n                                  |
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *   |    Kij Alg    |   Crypt Alg   |  MAC Alg      |  Comp Alg     |
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *   |    Kp encrypted in Kijn...          (typically 8-16 bytes)
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *   |    Source Master Key-ID  (If Source NSID is non-zero)
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *   |    Destination Master Key-ID (If Dest NSID is non-zero)
+ *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ */
+
+
+
+
+
+/*
+ * per name space key ID sizes...
+ */
+unsigned char   skip_nsid_sizes[MAX_ALGS] = {
+                          0,    /* 0  none */
+                          4,    /* 1  IP v4 Address Space */
+                          4,    /* 2  POSIX/XOPEN User Ids */
+                         16,    /* 3  IPv6 Address Space */
+                         16,    /* 4  MD5 of DNS Names */
+                         16,    /* 5  MD5 of ISO ASN.1 DN encoding */
+                         16,    /* 6  MD5 of US Social Security number */
+                          6,    /* 7  802.x MAC Address */
+                         16,    /* 8  MD5 of public Value */
+                         16,    /* 9  MD5 of RFC822 Mailbox Address */
+                         16,    /* 10 MD5 of Bank Account # */
+                         16,    /* 11 MD5 of NIS Name */
+                };
+
+
+/*
+ * per Kp algorithm encrypted Kp sizes... (Kij alg does not matter for now)
+ */
+unsigned char   skip_ekp_sizes[MAX_ALGS] = {
+                          0,    /* 0 plaintext */
+                          8,    /* 1 DES_CBC */
+                          24,   /* 2 3 key triple DES-EDE-CBC */
+                          0,    /* 3  */
+                          0,    /* 4  */
+                          0,    /* 5  */
+                          0,    /* 6  */
+                          0,    /* 7  */
+                          0,    /* 8  */
+                          0,    /* 9  */                        /* 10 .. 249 */
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+			  8,    /* 250 RC4-40 */                          
+			  16,   /* 251 RC4-128 */                          
+			  8,    /* 252 simple crypt */                          
+			  16,   /* 253 IDEA */                          
+			  0,    /* 254 */                          
+			  0     /* 255 */                          
+                };
+
+
+/*
+ * per-algorithm NSID names ...
+ */
+char            *skip_nsid_names[MAX_ALGS] = {
+                                        "none",             /* 0 */
+                                        "IPv4",             /* 1 */
+                                        "Posix/Xopen UID",  /* 2 */
+                                        "IPv6",             /* 3 */
+                                        "MD5 DNS",          /* 4 */
+                                        "MD5 ASN.1 DN",     /* 5 */
+                                        "MD5 U.S. Soc. #",  /* 6 */
+                                        "802.x MAC",        /* 7 */
+                                        "MD5 DH Public Key",/* 8 */
+                                        "MD5 RFC822 Mail",  /* 9 */
+                                        "MD5 Bank Account", /* 10 */
+                                        "MD5 NIS Name",     /* 11 */
+                };
+
+
+/*
+ * per-algorithm Kij alg names ...
+ */
+char            *skip_kij_names[MAX_ALGS] = {
+                                        "none",             /* 0 */
+                                        "DES-CBC",          /* 1 */
+                                        "3DES3-EDE-CBC",    /* 2 */
+                                        "IDEA-CBC",         /* 3 */
+		};
+
+
+/* for padding of ekp */
+
+char            skip_kij_sizes[MAX_ALGS] = {
+                                        0, /* 0 none */
+                                        8, /* 1  des-cbc */
+                                        8, /* 2 3des3-ede-cbc */
+                                        8, /* 3 idea-cbc */
+		};
+
+
+/*
+ * per-algorithm Crypt alg names ...
+ */
+char            *skip_crypt_names[MAX_ALGS] = {
+                                        "none",                      /* 0 */
+                                        "DES-CBC",                   /* 1 */
+                                        "3 key DES-EDE-CBC",         /* 2 */
+                                        "",                          /* 3 */
+                                        "",                          /* 4 */
+                                        "",                          /* 5 */
+                                        "",                          /* 6 */
+                                        "",                          /* 7 */
+                                        "",                          /* 8 */
+					"",   /* 9 */        /* 10 .. 249 */
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+					"RC4-40",                    /* 250 */ 
+					"RC4-128",                   /* 251 */
+					"simple crypt",              /* 252 */ 
+					"IDEA CBC",                  /* 253 */
+					"",                          /* 254 */ 
+					""                           /* 255 */
+                };
+
+
+/*
+ * per-algorithm Auth alg names ...
+ */
+char            *skip_auth_names[MAX_ALGS] = {
+                                        "none",        /* 0 */
+                                        "keyed MD5",   /* 1 */
+                                        "DES-CBC MAC", /* 2 */
+                                        "Keyed SHA",   /* 3 */
+                };
+
+
+char            skip_auth_sizes[MAX_ALGS] = {
+                                        0, 		/* 0 none */
+                                       16,	 	/* 1 keyed MD5 */
+                                        8, 		/* 2 DES-CBC MAC */
+                                       20, 		/* 3 Keyed SHA */
+                };
+
+
+/*
+ * per-algorithm Crypt alg IV sizes ...
+ */
+char            skip_crypt_sizes[MAX_ALGS] = {
+                                        0, /* 0 none */
+                                        8, /* 1 DES-CBC */
+                                        8, /* 2 3key DES-EDE-CBC */
+                                        0, /* 3 */
+                                        0, /* 4 */
+                                        0, /* 5 */
+                                        0, /* 6 */
+                                        0, /* 7 */
+                                        0, /* 8 */
+					0, /* 9 */        /* 10 .. 249 */
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+					8, /* 250 RC4-40 */ 
+				        8, /* 251 RC4-128 */
+					8, /* 252 simple crypt */ 
+					8, /* 253 IDEA CBC */
+					0, /* 254 */ 
+					0  /* 255 */
+                };
+
+
+#ifndef IPPROTO_ESP
+#define IPPROTO_ESP 50
+#endif
+#ifndef IPPROTO_AH
+#define IPPROTO_AH 51
+#endif
+#ifndef IPPROTO_SKIP
+#define IPPROTO_SKIP 57
+#endif
+#ifndef IPPROTO_OSKIP
+#define IPPROTO_OSKIP 79
+#endif
+
+static int expected_auth_size=0;
+static int expected_iv_size=0;
+
+char *skip_protocol_name(int p)
+{
+    switch(p) {
+	case IPPROTO_IP:    return "IP";
+	case IPPROTO_ICMP:  return "ICMP";
+	case IPPROTO_IGMP:  return "IGMP";
+	case IPPROTO_ENCAP: return "ENCAP";
+	case IPPROTO_TCP:   return "TCP";
+	case IPPROTO_EGP:   return "EGP";
+	case IPPROTO_UDP:   return "UDP";
+	case IPPROTO_ESP:   return "ESP";
+	case IPPROTO_AH:    return "AH";
+	case IPPROTO_SKIP:  return "SKIP";
+	case IPPROTO_ND:    return "ND";
+	case IPPROTO_OSKIP: return "OLD-SKIP";
+	case IPPROTO_RAW:   return "RAW IP";
+	default:            return "<unknown>";
+    }
+}
+
+void skip_print_next(u_char nxt, const u_char *p, int len, const u_char *bp2)
+{
+    switch(nxt) {
+	case IPPROTO_IP:   ip_print(p,len); break;
+	case IPPROTO_ICMP: icmp_print(p,bp2); break;
+	case IPPROTO_TCP:  tcp_print(p,len,bp2); break;
+	case IPPROTO_UDP:  udp_print(p,len,bp2); break;
+	case IPPROTO_ESP:  esp_print(p,len,bp2); break;
+	case IPPROTO_AH:   ah_print(p,len,bp2); break;
+	case IPPROTO_SKIP: skip_print(p,len,bp2); break;
+	default: break;
+    }
+}
+
+void skip_print(register const u_char *bp, register int length, 
+							const u_char *bp2)
+{
+	struct ip *ip;
+	const u_char *end;
+	const u_char *p;
+	unsigned char	kij_alg, crypt_alg, auth_alg, snsid, dnsid, nxt;
+	unsigned short i;
+	unsigned short len;
+	u_int n;
+	time_t full_n;
+
+	ip=(struct ip *)bp2;
+	p=bp;
+	end=bp+length<snapend?bp+length:snapend;
+
+	printf("%s>%s:%d SKIP",ipaddr_string(&ip->ip_src),
+			       ipaddr_string(&ip->ip_dst),length);
+	if (!skipflag)
+		return;
+
+
+        if ((unsigned short) (end - p) < 4) {
+	    printf("[SKIP|] (truncated)\n");
+	    return;
+        }
+
+	printf("\nSKIP: version\t\t\t%d\n", (int) (*p & 0xf0) >> 4);
+	if (*p & 0xf) 
+		printf("SKIP: version byte \t\treserved,\tis now 0x%x\n", 
+							(int) (*p & 0xf));
+        p++;
+
+        snsid = *p;
+        printf("SKIP: Source NSID\t\t0x%02x\t\t%s\n",
+		    snsid, skip_alg_to_name(skip_nsid_names,snsid));
+        p++;
+
+        dnsid = *p;
+        printf("SKIP: Destination NSID\t\t0x%02x\t\t%s\n",
+		    dnsid, skip_alg_to_name(skip_nsid_names,dnsid));
+        p++;
+
+        nxt = *p;
+        printf("SKIP: Next Protocol Field\t0x%02x\t\t%s\n", nxt, 
+						    skip_protocol_name(nxt));
+ 
+        p++;
+
+        if ((unsigned short) (end - p) < 4) {
+	    printf("[SKIP|] (truncated)\n");
+	    return;
+        }
+
+	n=*p++<<24; 
+	n+=*p++<<16;
+	n+=*p++<<8;
+	n+=*p;
+	full_n=(((365*25+6)*24)+n)*3600;
+        printf("SKIP: Counter n Field\t\t0x%08x\t%s", n, 
+						asctime(gmtime(&full_n)));
+        p++;
+
+        if ((unsigned short) (end - p) < 4) {
+	    printf("[SKIP|] (truncated)\n");
+	    return;
+        }
+
+        kij_alg = *p;
+        printf("SKIP: Kij alg (key encryption)\t0x%02x\t\t%s\n",
+		    kij_alg, skip_alg_to_name(skip_kij_names,kij_alg));
+        p++;
+ 
+        crypt_alg = *p;
+	expected_iv_size=skip_crypt_sizes[crypt_alg];
+        printf("SKIP: Crypt Alg\t\t\t0x%02x\t\t%s\n",
+		    crypt_alg, skip_alg_to_name(skip_crypt_names,crypt_alg));
+        p++;
+ 
+        auth_alg = *p;
+	expected_auth_size=skip_auth_sizes[auth_alg];
+        printf("SKIP: Auth Alg\t\t\t0x%02x\t\t%s\n",
+		    auth_alg, skip_alg_to_name(skip_auth_names,auth_alg));
+        p++;
+ 
+        if (*p) printf("SKIP: compression\t\treserved,\tis now0x%02x\n",
+								(int) *p++);
+        else p++;
+
+        /*
+         * encrypted kp (ekp) field
+         */
+
+	if (kij_alg==0 && (crypt_alg || auth_alg)) {
+	    printf("Warning: Kij Alg. undefined, but Auth. or Crypt. used!");
+	    printf("Warning: Assuming empty Kp\n");
+	    crypt_alg=auth_alg=0;
+	}
+        /*
+         * do this with a for-loop to avoid alignment problems and the
+         * overhead of calling bcopy()
+         */
+        len = skip_ekp_sizes[crypt_alg];
+        len = len>(int)skip_auth_sizes[auth_alg]?len:skip_auth_sizes[auth_alg];
+        if (len && skip_kij_sizes[kij_alg] && len % skip_kij_sizes[kij_alg]) {
+	    len += skip_kij_sizes[kij_alg] - (len%skip_kij_sizes[kij_alg]);
+	}
+        if ((unsigned short) (end - p) < len) {
+	    printf("[SKIP|] (truncated)\n");
+	    return;
+        }
+
+        printf("SKIP: Encrypted Kp\t\t");
+        for (i = 0; i < len; i++) {
+                printf("%02x ", (unsigned char) *p++);
+        }
+        printf("\n");
+
+
+        if (snsid) {
+        /*
+         * Source Master Key-ID field
+         */
+	    if ((end - p) < skip_nsid_sizes[snsid]) {
+		printf("[SKIP|] (truncated)\n");
+		return;
+	    }
+	    printf("SKIP: Source Master Key-ID\t");
+            if (snsid==1) {
+		printf("%s",ipaddr_string(p));
+		p+=skip_nsid_sizes[snsid];
+	    } else {
+		for (i = 0; i < skip_nsid_sizes[snsid]; i++) {
+		    printf("%02x ", (unsigned char) *p++);
+		}
+	    }
+	    printf("\n");
+        }
+
+        if (dnsid) {
+        /*
+         * Destination Master Key-ID field
+         */
+	    if ((end - p) < skip_nsid_sizes[dnsid]) {
+		printf("[SKIP|] (truncated)\n");
+		return;
+	    }
+	    printf("SKIP: Dest. Master Key-ID\t");
+            if (dnsid==1) {
+		printf("%s",ipaddr_string(p));
+		p+=skip_nsid_sizes[dnsid];
+	    } else {
+		for (i = 0; i < skip_nsid_sizes[dnsid]; i++) {
+		    printf("%02x ", (unsigned char) *p++);
+		}
+	    }
+	    printf("\n");
+        }
+        if (p<end) skip_print_next(nxt,p,end-p,bp2);
+        else printf("(truncated)\n");
+}
+
+
+
+void ah_print(register const u_char *bp, register int length, 
+							const u_char *bp2)
+{
+	struct ip *ip;
+	const u_char *end;
+	const u_char *p;
+	u_char	nxt;
+	int len, i;
+	u_int spi;
+
+	ip=(struct ip *)bp2;
+	p=bp;
+	end=bp+length<snapend?bp+length:snapend;
+
+
+	printf("SKIP-AH: %s>%s:%d",ipaddr_string(&ip->ip_src),
+			       ipaddr_string(&ip->ip_dst),length);
+	if (!skipflag)
+		return;
+
+	if (end-p <4) {
+            printf("[SKIP-AH|]\n");
+	    return;
+	}
+
+        nxt = *p;
+        printf("\nSKIP-AH: Next Protocol Field\t0x%02x\t\t%s\n", nxt, 
+						    skip_protocol_name(nxt));
+        p++;
+
+	len= 4 * (int) *p;
+	printf("SKIP-AH: length\t\t\t%d\n", len);
+
+        p++;
+
+        if (*p) printf("SKIP-AH: byte 3\t\t\treserved,\tis now0x%02x\n",
+								(int) *p++);
+        else p++;
+        if (*p) printf("SKIP-AH: byte 4\t\t\treserved,\tis now0x%02x\n",
+								(int) *p++);
+        else p++;
+
+	if (end-p <4) {
+            printf("[SKIP-AH|]\n");
+	    return;
+	}
+
+	spi=*p++<<24; 
+	spi+=*p++<<16;
+	spi+=*p++<<8;
+	spi+=*p;
+        printf("SKIP-AH: SPI\t\t\t0x%08x\t", spi );
+	if (spi==0) {
+	    printf("NO association\n");
+	} else if (spi==1) {
+	    printf("SKIP association\n");
+	    if (expected_auth_size) {
+		if (expected_auth_size != len) {
+		    printf("Warning: Length does not match SKIP Auth Alg!\n");
+		}
+		expected_auth_size=0;
+	    }
+	} else if (spi<256) {
+	    printf("UNKNOWN association\n");
+	} else {
+	    printf("DYNAMIC association\n");
+        }
+
+        p++;
+ 
+
+        /*
+         * authentication data
+         */
+
+        if ((unsigned short) (end - p) < len) {
+	    printf("[SKIP-AH|] (truncated)\n");
+	    return;
+        }
+
+        printf("SKIP-AH: Authentication Data\t");
+        for (i = 0; i < len; i++) {
+                printf("%02x ", (unsigned char) *p++);
+		if (i<len-1 && (i+1)%16==0) printf("\n\t\t\t\t");
+        }
+        printf("\n");
+
+        if (p<end) skip_print_next(nxt,p,end-p,bp2);
+        else printf("(truncated)\n");
+}
+
+
+void esp_print(register const u_char *bp, register int length, 
+							const u_char *bp2)
+{
+	struct ip *ip;
+	const u_char *end;
+	const u_char *p;
+	int len, i;
+	u_int spi;
+
+	ip=(struct ip *)bp2;
+	p=bp;
+	end=bp+length<snapend?bp+length:snapend;
+
+
+	printf("SKIP-ESP: %s>%s:%d",ipaddr_string(&ip->ip_src),
+			       ipaddr_string(&ip->ip_dst),length);
+	if (!skipflag)
+		return;
+
+	if (end-p <4) {
+            printf("[SKIP-ESP|]\n");
+	}
+
+	spi=*p++<<24; 
+	spi+=*p++<<16;
+	spi+=*p++<<8;
+	spi+=*p;
+        printf("\nSKIP-ESP: SPI\t\t\t0x%08x\t", spi );
+	if (spi==0) {
+	    printf("NO association\n");
+	    len=0;
+	} else if (spi==1) {
+	    printf("SKIP association\n");
+	    len=expected_iv_size;
+	    if (!expected_iv_size) {
+		printf("Warning: IV size not defined by SKIP Crypt Alg!\n");
+	    } else expected_iv_size=0;
+	} else if (spi<256) {
+	    printf("UNKNOWN association\n");
+	    len=0;
+	} else {
+	    printf("DYNAMIC association\n");
+	    len=0;
+        }
+
+        p++;
+ 
+        /*
+         * IV data
+         */
+
+        if ((unsigned short) (end - p) < len) {
+	    printf("[SKIP-ESP|] (truncated)\n");
+	    return;
+        }
+
+        printf("SKIP-ESP: Initalization Vector\t");
+	if (len) {
+	    for (i = 0; i < len; i++) {
+		    printf("%02x ", (unsigned char) *p++);
+		    if (i<len-1 && (i+1)%16==0) printf("\n\t\t\t\t");
+	    }
+        } else {
+	    printf("UNDEFINED (unknown algorithm)");
+	}
+	printf("\n");
+
+	/* no further analysis is possible without decrypting */
+}
+