/*
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code
 * distributions retain the above copyright notice and this paragraph
 * in its entirety, and (2) distributions including binary code include
 * the above copyright notice and this paragraph in its entirety in
 * the documentation or other materials provided with the distribution.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE.
 *
 * Original code by Hannes Gredler (hannes@juniper.net)
 */

#ifdef HAVE_CONFIG_H
#include "argus_config.h"
#endif

#include <unistd.h>
#include <stdlib.h>

#include <rabins.h>
#include <argus_util.h>
#include <argus_client.h>
#include <argus_main.h>
#include <argus_filter.h>

#include <signal.h>
#include <ctype.h>
#include <argus/extract.h>

extern u_char *snapend;

#include "interface.h"
extern char ArgusBuf[];

/*
 * Control packet, BFDv0, draft-katz-ward-bfd-01.txt
 *
 *     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
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |Vers |  Diag   |H|D|P|F| Rsvd  |  Detect Mult  |    Length     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                       My Discriminator                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                      Your Discriminator                       |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                    Desired Min TX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                   Required Min RX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                 Required Min Echo RX Interval                 |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

/* 
 *  Control packet, BFDv1, draft-ietf-bfd-base-02.txt
 *
 *     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
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |Vers |  Diag   |Sta|P|F|C|A|D|R|  Detect Mult  |    Length     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                       My Discriminator                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                      Your Discriminator                       |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                    Desired Min TX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                   Required Min RX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                 Required Min Echo RX Interval                 |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct bfd_header_t {
    u_int8_t version_diag;
    u_int8_t flags;
    u_int8_t detect_time_multiplier;
    u_int8_t length;
    u_int8_t my_discriminator[4];
    u_int8_t your_discriminator[4];
    u_int8_t desired_min_tx_interval[4];
    u_int8_t required_min_rx_interval[4];
    u_int8_t required_min_echo_interval[4];
};

/*
 *    An optional Authentication Header may be present
 *
 *     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
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   Auth Type   |   Auth Len    |    Authentication Data...     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct bfd_auth_header_t {
    u_int8_t auth_type;
    u_int8_t auth_len;
    u_int8_t auth_data;
};

static const struct tok bfd_v1_authentication_values[] = {
    { 0,        "Reserved" },
    { 1,        "Simple Password" },
    { 2,        "Keyed MD5" },
    { 3,        "Meticulous Keyed MD5" },
    { 4,        "Keyed SHA1" },
    { 5,        "Meticulous Keyed SHA1" },
    { 0, NULL }
};

#define	BFD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
#define	BFD_EXTRACT_DIAG(x)     ((x)&0x1f)

static const struct tok bfd_port_values[] = {
    { BFD_CONTROL_PORT, "Control" },
    { BFD_ECHO_PORT,    "Echo" },
    { 0, NULL }
};


static const struct tok bfd_diag_values[] = {
    { 0, "No Diagnostic" },
    { 1, "Control Detection Time Expired" },
    { 2, "Echo Function Failed" },
    { 3, "Neighbor Signaled Session Down" },
    { 4, "Forwarding Plane Reset" },
    { 5, "Path Down" },
    { 6, "Concatenated Path Down" },
    { 7, "Administratively Down" },
    { 8, "Reverse Concatenated Path Down" },
    { 0, NULL }
};

static const struct tok bfd_v0_flag_values[] = {
    { 0x80,	"I Hear You" },
    { 0x40,	"Demand" },
    { 0x20,	"Poll" },
    { 0x10,	"Final" },
    { 0x08,	"Reserved" },
    { 0x04,	"Reserved" },
    { 0x02,	"Reserved" },
    { 0x01,	"Reserved" },
    { 0, NULL }
};

#define BFD_FLAG_AUTH 0x04

static const struct tok bfd_v1_flag_values[] = {
    { 0x20, "Poll" },
    { 0x10, "Final" },
    { 0x08, "Control Plane Independent" },
    { BFD_FLAG_AUTH, "Authentication Present" },
    { 0x02, "Demand" },
    { 0x01, "Reserved" },
    { 0, NULL }
};

static const struct tok bfd_v1_state_values[] = {
    { 0, "AdminDown" },
    { 1, "Down" },
    { 2, "Init" },
    { 3, "Up" },
    { 0, NULL }
};

char *
bfd_print(register const u_char *pptr, register u_int len, register u_int port)
{
   const struct bfd_header_t *bfd_header;
   const struct bfd_auth_header_t *bfd_auth_header;
   u_int8_t version;

   bfd_header = (const struct bfd_header_t *)pptr;
   TCHECK(*bfd_header);
   version = BFD_EXTRACT_VERSION(bfd_header->version_diag);

   switch (port << 8 | version) {

       /* BFDv0 */
   case (BFD_CONTROL_PORT << 8):
       if (ArgusParser->vflag < 1 ) {
           sprintf(&ArgusBuf[strlen(ArgusBuf)],"BFDv%u, %s, Flags: [%s], length: %u",
                  version,
                  tok2str(bfd_port_values, "unknown (%u)", port),
                  bittok2str(bfd_v0_flag_values, "none", bfd_header->flags),
                  len);
           return ArgusBuf;
       }
       
       sprintf(&ArgusBuf[strlen(ArgusBuf)],"BFDv%u, length: %u %s, Flags: [%s], Diagnostic: %s (0x%02x)",
              version,
              len,
              tok2str(bfd_port_values, "unknown (%u)", port),
              bittok2str(bfd_v0_flag_values, "none", bfd_header->flags),
              tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(bfd_header->version_diag)),
              BFD_EXTRACT_DIAG(bfd_header->version_diag));
       
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Detection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
              bfd_header->detect_time_multiplier,
              bfd_header->detect_time_multiplier * EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000,
              bfd_header->length);


       sprintf(&ArgusBuf[strlen(ArgusBuf)]," My Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->my_discriminator));
       sprintf(&ArgusBuf[strlen(ArgusBuf)],", Your Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->your_discriminator));
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Desired min Tx Interval:    %4u ms", EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000);
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Required min Rx Interval:   %4u ms", EXTRACT_32BITS(bfd_header->required_min_rx_interval)/1000);
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Required min Echo Interval: %4u ms", EXTRACT_32BITS(bfd_header->required_min_echo_interval)/1000);
       break;

       /* BFDv1 */
   case (BFD_CONTROL_PORT << 8 | 1):
       if (ArgusParser->vflag < 1 ) {
           sprintf(&ArgusBuf[strlen(ArgusBuf)],"BFDv%u, %s, State %s, Flags: [%s], length: %u",
                  version,
                  tok2str(bfd_port_values, "unknown (%u)", port),
                  tok2str(bfd_v1_state_values, "unknown (%u)", bfd_header->flags & 0xc0),
                  bittok2str(bfd_v1_flag_values, "none", bfd_header->flags & 0x3f),
                  len);
           return ArgusBuf;
       }
       
       sprintf(&ArgusBuf[strlen(ArgusBuf)],"BFDv%u, length: %u %s, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
              version,
              len,
              tok2str(bfd_port_values, "unknown (%u)", port),
              tok2str(bfd_v1_state_values, "unknown (%u)", (bfd_header->flags & 0xc0) >> 6),
              bittok2str(bfd_v1_flag_values, "none", bfd_header->flags & 0x3f),
              tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(bfd_header->version_diag)),
              BFD_EXTRACT_DIAG(bfd_header->version_diag));
       
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Detection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
              bfd_header->detect_time_multiplier,
              bfd_header->detect_time_multiplier * EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000,
              bfd_header->length);


       sprintf(&ArgusBuf[strlen(ArgusBuf)]," My Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->my_discriminator));
       sprintf(&ArgusBuf[strlen(ArgusBuf)],", Your Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->your_discriminator));
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Desired min Tx Interval:    %4u ms", EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000);
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Required min Rx Interval:   %4u ms", EXTRACT_32BITS(bfd_header->required_min_rx_interval)/1000);
       sprintf(&ArgusBuf[strlen(ArgusBuf)]," Required min Echo Interval: %4u ms", EXTRACT_32BITS(bfd_header->required_min_echo_interval)/1000);

       if (bfd_header->flags & BFD_FLAG_AUTH) {
           pptr += sizeof (const struct bfd_header_t);
           bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
           TCHECK2(*bfd_auth_header, sizeof(const struct bfd_auth_header_t));
           sprintf(&ArgusBuf[strlen(ArgusBuf)]," %s (%u) Authentication, length %u present",
                  tok2str(bfd_v1_authentication_values,"Unknown",bfd_auth_header->auth_type),
                  bfd_auth_header->auth_type,
                  bfd_auth_header->auth_len);
       }
       break;

       /* BFDv0 */
   case (BFD_ECHO_PORT << 8): /* not yet supported - fall through */
       /* BFDv1 */
   case (BFD_ECHO_PORT << 8 | 1):

   default:
       sprintf(&ArgusBuf[strlen(ArgusBuf)],"BFD, %s, length: %u",
              tok2str(bfd_port_values, "unknown (%u)", port),
              len);
       if (ArgusParser->vflag >= 1) {
           if(!print_unknown_data(pptr," ",len))
               return ArgusBuf;
       }
       break;
   }
   return ArgusBuf;

trunc:
   sprintf(&ArgusBuf[strlen(ArgusBuf)],"[|BFD]");

   return ArgusBuf;
}
