_bootp.c

This directory contains source code for tcpdump, a tool for network monitoring and data acquisition

/*
 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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, (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, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * 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.
 *
 * Format and print bootp packets.
 */

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include <sys/param.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>

#include "interfac.h"
#include "a2name.h"
#include "bootp.h"

static void rfc1048_print (const u_char *, u_int);
static void cmu_print     (const u_char *, u_int);

static char tstr[] = " [|bootp]";

/*
 * Print bootp requests
 */
void bootp_print (const u_char *cp, u_int length,
                  u_short sport, u_short dport)
{
  const  struct bootp *bp;
  static char   vm_cmu[4]     = VM_CMU;
  static u_char vm_rfc1048[4] = VM_RFC1048;

  bp = (struct bootp*)cp;
  TCHECK (bp->bp_op);

  switch (bp->bp_op)
  {
    case BOOTREQUEST:
         /* Usually, a request goes from a client to a server
          */
         if (sport != IPPORT_BOOTPC || dport != IPPORT_BOOTPS)
            PUTS (" (request)");
         break;

    case BOOTREPLY:
         /* Usually, a reply goes from a server to a client
          */
         if (sport != IPPORT_BOOTPS || dport != IPPORT_BOOTPC)
            PUTS (" (reply)");
         break;

    default:
         PRINTF (" bootp-#%d", bp->bp_op);
  }

  TCHECK (bp->bp_secs);

  /* The usual hardware address type is 1 (10Mb Ethernet)
   */
  if (bp->bp_htype != 1)
     PRINTF (" htype-#%d", bp->bp_htype);

  /* The usual length for 10Mb Ethernet address is 6 bytes
   */
  if (bp->bp_htype != 1 || bp->bp_hlen != 6)
     PRINTF (" hlen:%d", bp->bp_hlen);

  /* Only print interesting fields
   */
  if (bp->bp_hops)
     PRINTF (" hops:%d", bp->bp_hops);

  if (bp->bp_xid)
     PRINTF (" xid:0x%lx", ntohl (bp->bp_xid));

  if (bp->bp_secs)
     PRINTF (" secs:%d", ntohs (bp->bp_secs));

  if (bp->bp_flags)
     PRINTF (" flags:0x%x", ntohs(bp->bp_flags));

  /* Client's ip address
   */
  TCHECK (bp->bp_ciaddr);
  if (bp->bp_ciaddr.s_addr)
     PRINTF (" C:%s", ipaddr_string (&bp->bp_ciaddr));

  /* 'your' ip address (bootp client)
   */
  TCHECK (bp->bp_yiaddr);
  if (bp->bp_yiaddr.s_addr)
     PRINTF (" Y:%s", ipaddr_string (&bp->bp_yiaddr));

  /* Server's ip address
   */
  TCHECK (bp->bp_siaddr);
  if (bp->bp_siaddr.s_addr)
     PRINTF (" S:%s", ipaddr_string (&bp->bp_siaddr));

  /* Gateway's ip address
   */
  TCHECK (bp->bp_giaddr);
  if (bp->bp_giaddr.s_addr)
     PRINTF (" G:%s", ipaddr_string (&bp->bp_giaddr));

  /* Client's Ethernet address
   */
  if (bp->bp_htype == 1 && bp->bp_hlen == 6)
  {
    const struct ether_header *eh = (struct ether_header*) packetp;
    const char  *e;

    TCHECK2 (bp->bp_chaddr[0], 6);

    if (bp->bp_op == BOOTREQUEST)
         e = (const char*) ESRC (eh);
    else if (bp->bp_op == BOOTREPLY)
         e = (const char*) EDST (eh);
    else e = NULL;
    if (!e || memcmp(bp->bp_chaddr,e,6))
       PRINTF (" ether %s", etheraddr_string (bp->bp_chaddr));
  }

  TCHECK2 (bp->bp_sname[0], 1); /* check first char only */
  if (*bp->bp_sname)
  {
    PUTS (" sname \"");
    if (fn_print ((char*)bp->bp_sname, (char*)snapend))
    {
      PUTCHAR ('"');
      PUTS (tstr+1);
      return;
    }
  }
  TCHECK2 (bp->bp_sname[0], 1); /* check first char only */
  if (*bp->bp_file)
  {
    PUTS (" file \"");
    if (fn_print((char *)bp->bp_file,(char*)snapend))
    {
      PUTCHAR ('"');
      PUTS (tstr+1);
      return;
    }
  }

  /* Decode the vendor buffer
   */
  TCHECK (bp->bp_vend[0]);
  length -= sizeof(*bp) - sizeof(bp->bp_vend);

  if (!memcmp(bp->bp_vend,vm_rfc1048,sizeof(u_int32_t)))
       rfc1048_print (bp->bp_vend, length);
  else if (!memcmp (bp->bp_vend, vm_cmu,sizeof(u_int32_t)))
       cmu_print (bp->bp_vend, length);
  else
  {
    u_int32_t ul;

    memcpy (&ul,bp->bp_vend,sizeof(ul));
    if (ul)
       PRINTF ("vend-#0x%lx", ul);
  }
  return;

trunc:
  PUTS (tstr);
}

/*
 * The first character specifies the format to print
 */
static struct tok tag2str[] = {

  /* RFC1048 tags */
  { TAG_PAD,               " PAD"  },
  { TAG_SUBNET_MASK,       "iSM"   },   /* subnet mask (RFC950) */
  { TAG_TIME_OFFSET,       "lTZ"   },   /* seconds from UTC */
  { TAG_GATEWAY,           "iDG"   },   /* default gateway */
  { TAG_TIME_SERVER,       "iTS"   },   /* time servers (RFC868) */
  { TAG_NAME_SERVER,       "iIEN"  },   /* IEN name servers (IEN116) */
  { TAG_DOMAIN_SERVER,     "iNS"   },   /* domain name (RFC1035) */
  { TAG_LOG_SERVER,        "iLOG"  },   /* MIT log servers */
  { TAG_COOKIE_SERVER,     "iCS"   },   /* cookie servers (RFC865) */
  { TAG_LPR_SERVER,        "iLPR"  },   /* lpr server (RFC1179) */
  { TAG_IMPRESS_SERVER,    "iIM"   },   /* impress servers (Imagen) */
  { TAG_RLP_SERVER,        "iRL"   },   /* resource location (RFC887) */
  { TAG_HOSTNAME,          "aHN"   },   /* ascii hostname */
  { TAG_BOOTSIZE,          "sBS"   },   /* 512 byte blocks */
  { TAG_END,               " END"  },

  /* RFC1497 tags */
  { TAG_DUMPPATH,          "aDP"   },
  { TAG_DOMAINNAME,        "aDN"   },
  { TAG_SWAP_SERVER,       "iSS"   },
  { TAG_ROOTPATH,          "aRP"   },
  { TAG_EXTPATH,           "aEP"   },

  /* RFC2132 tags */
  { TAG_IP_FORWARD,        "BIPF"  },
  { TAG_NL_SRCRT,          "BSRT"  },
  { TAG_PFILTERS,          "pPF"   },
  { TAG_REASS_SIZE,        "sRSZ"  },
  { TAG_DEF_TTL,           "bTTL"  },
  { TAG_MTU_TIMEOUT,       "lMA"   },
  { TAG_MTU_TABLE,         "sMT"   },
  { TAG_INT_MTU,           "sMTU"  },
  { TAG_LOCAL_SUBNETS,     "BLSN"  },
  { TAG_BROAD_ADDR,        "iBR"   },
  { TAG_DO_MASK_DISC,      "BMD"   },
  { TAG_SUPPLY_MASK,       "BMS"   },
  { TAG_DO_RDISC,          "BRD"   },
  { TAG_RTR_SOL_ADDR,      "iRSA"  },
  { TAG_STATIC_ROUTE,      "pSR"   },
  { TAG_USE_TRAILERS,      "BUT"   },
  { TAG_ARP_TIMEOUT,       "lAT"   },
  { TAG_ETH_ENCAP,         "BIE"   },
  { TAG_TCP_TTL,           "bTT"   },
  { TAG_TCP_KEEPALIVE,     "lKI"   },
  { TAG_KEEPALIVE_GO,      "BKG"   },
  { TAG_NIS_DOMAIN,        "aYD"   },
  { TAG_NIS_SERVERS,       "iYS"   },
  { TAG_NTP_SERVERS,       "iNTP"  },
  { TAG_VENDOR_OPTS,       "bVO"   },
  { TAG_NETBIOS_NS,        "iWNS"  },
  { TAG_NETBIOS_DDS,       "iWDD"  },
  { TAG_NETBIOS_NODE,      "bWNT"  },
  { TAG_NETBIOS_SCOPE,     "aWSC"  },
  { TAG_XWIN_FS,           "iXFS"  },
  { TAG_XWIN_DM,           "iXDM"  },
  { TAG_NIS_P_DOMAIN,      "sN+D"  },
  { TAG_NIS_P_SERVERS,     "iN+S"  },
  { TAG_MOBILE_HOME,       "iMH"   },
  { TAG_SMPT_SERVER,       "iSMTP" },
  { TAG_POP3_SERVER,       "iPOP3" },
  { TAG_NNTP_SERVER,       "iNNTP" },
  { TAG_WWW_SERVER,        "iWWW"  },
  { TAG_FINGER_SERVER,     "iFG"   },
  { TAG_IRC_SERVER,        "iIRC"  },
  { TAG_STREETTALK_SRVR,   "iSTS"  },
  { TAG_STREETTALK_STDA,   "iSTDA" },
  { TAG_REQUESTED_IP,      "iRQ"   },
  { TAG_IP_LEASE,          "lLT"   },
  { TAG_OPT_OVERLOAD,      "bOO"   },
  { TAG_TFTP_SERVER,       "aTFTP" },
  { TAG_BOOTFILENAME,      "aBF"   },
  { TAG_DHCP_MESSAGE,      " DHCP" },
  { TAG_SERVER_ID,         "iSID"  },
  { TAG_PARM_REQUEST,      "bPR"   },
  { TAG_MESSAGE,           "aMSG"  },
  { TAG_MAX_MSG_SIZE,      "sMSZ"  },
  { TAG_RENEWAL_TIME,      "lRN"   },
  { TAG_REBIND_TIME,       "lRB"   },
  { TAG_VENDOR_CLASS,      "bVC"   },
  { TAG_CLIENT_ID,         "xCID"  },  /* !! was "bCID" */
  { 0,                     NULL    }
};

static void rfc1048_print (const u_char *bp, u_int length)
{
  u_char  tag;
  u_int   len, size, ul;
  u_short us;
  const   char *cp;
  char    c;
  int     first;

  PUTS (" vend-rfc1048");

  bp += sizeof(u_long);   /* Step over magic cookie */

  /* Loop while we there is a tag left in the buffer
   */
  while (bp + 1 < snapend)
  {
    tag = *bp++;
    if (tag == TAG_PAD)
       continue;

    if (tag == TAG_END)
       return;

    cp = tok2str (tag2str, "?T%d", (int)tag);
    c  = *cp++;
    PRINTF (" %s:", cp);

    /* Get the length; check for truncation
     */
    if (bp + 1 >= snapend)
    {
      PUTS (tstr);
      return;
    }
    len = *bp++;
    if (bp + len >= snapend)
    {
      PUTS (tstr);
      return;
    }

    if (tag == TAG_DHCP_MESSAGE && len == 1)
    {
      c = *bp++;
      switch (c)
      {
        case DHCPDISCOVER: PRINTF ("DISCOVER"); break;
        case DHCPOFFER:    PRINTF ("OFFER");    break;
        case DHCPREQUEST:  PRINTF ("REQUEST");  break;
        case DHCPDECLINE:  PRINTF ("DECLINE");  break;
        case DHCPACK:      PRINTF ("ACK");      break;
        case DHCPNAK:      PRINTF ("NACK");     break;
        case DHCPRELEASE:  PRINTF ("RELEASE");  break;
        case DHCPINFORM:   PRINTF ("INFORM");   break;
        default:           PRINTF ("%u", c);    break;
      }
      continue;
    }

    if (tag == TAG_PARM_REQUEST)
    {
      first = 1;
      while (len-- > 0)
      {
        c = *bp++;
        cp = tok2str (tag2str, "?%d", (int)c);
        if (!first)
             PUTCHAR ('+');
        PRINTF ("%s", cp + 1);
        first = 0;
      }
      continue;
    }

    /* Print data */
    size = len;
    if (c == '?')
    {
      /* Base default formats for unknown tags on data size
       */
      if (size & 1)
           c = 'b';
      else if (size & 2)
           c = 's';
      else c = 'l';
    }
    first = 1;

    switch (c)
    {
      case 'a':
           /* ascii strings */
           PUTCHAR ('"');
           fn_printn ((char *)bp, size, NULL);
           PUTCHAR ('"');
           bp += size;
           size = 0;
           break;

      case 'i':
      case 'l':
           /* ip addresses/32-bit words */
           while (size >= sizeof(ul))
           {
             if (!first)
                PUTCHAR (',');
             memcpy ((char*)&ul, (char*)bp, sizeof(ul));
             if (c == 'i')
                  PUTS (ipaddr_string (&ul));
             else PRINTF ("%u", ul);
             bp   += sizeof(ul);
             size -= sizeof(ul);
             first = 0;
           }
           break;

      case 'p':
           /* IP address pairs */
           while (size >= 2*sizeof(ul))
           {
             if (!first)
                PUTCHAR (',');
             memcpy ((char *)&ul, (char *)bp, sizeof(ul));
             PRINTF ("(%s:", ipaddr_string(&ul));
             bp += sizeof(ul);
             memcpy ((char *)&ul, (char *)bp, sizeof(ul));
             PRINTF ("%s)", ipaddr_string(&ul));
             bp   += sizeof(ul);
             size -= 2*sizeof(ul);
             first = 0;
           }
           break;

      case 's':
           /* shorts */
           while (size >= sizeof(us))
           {
             if (!first)
                PUTCHAR (',');
             memcpy ((char*)&us, (char*)bp, sizeof(us));
             PRINTF ("%d", us);
             bp   += sizeof(us);
             size -= sizeof(us);
             first = 0;
           }
           break;

      case 'B':
           /* boolean */
           while (size > 0)
           {
             if (!first)
                PUTCHAR (',');
             switch (*bp)
             {
               case 0:
                    PUTCHAR ('N');
                    break;
               case 1:
                    PUTCHAR ('Y');
                    break;
               default:
                    PRINTF ("%d?", *bp);
                    break;
             }
             ++bp;
             --size;
             first = 0;
           }
           break;

      case 'b':
      case 'x':
      default:
           /* Bytes */
           while (size > 0)
           {
             if (!first)
                PUTCHAR (c == 'x' ? ':' : '.');
             PRINTF (c == 'x' ? "%02x" : "%d", *bp);
             ++bp;
             --size;
             first = 0;
           }
           break;
    }

    /* Data left over?
     */
    if (size)
       PRINTF ("[len %d]", len);
  }
}

static void cmu_print (const u_char *bp, u_int length)
{
  const struct cmu_vend *cmu = (struct cmu_vend*)bp;
  char *fmt = " %s:%s";

#define PRINTCMUADDR(m,s) {  \
          TCHECK(cmu->m);    \
          if (cmu->m.s_addr) \
             PRINTF (fmt, s, ipaddr_string(&cmu->m.s_addr)); \
        }

  PUTS (" vend-cmu");

  /* Only print if there are unknown bits
   */
  TCHECK (cmu->v_flags);
  if ((cmu->v_flags & ~(VF_SMASK)))
     PRINTF (" F:0x%lx", cmu->v_flags);

  PRINTCMUADDR (v_dgate,"DG");
  PRINTCMUADDR (v_smask, cmu->v_flags & VF_SMASK ? "SM" : "SM*");
  PRINTCMUADDR (v_dns1, "NS1");
  PRINTCMUADDR (v_dns2, "NS2");
  PRINTCMUADDR (v_ins1, "IEN1");
  PRINTCMUADDR (v_ins2, "IEN2");
  PRINTCMUADDR (v_ts1,  "TS1");
  PRINTCMUADDR (v_ts2,  "TS2");
  return;

trunc:
  PUTS (tstr);
  ARGSUSED (length);
}