udp.c

/*
 * Copyright (c) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
 *               2002, 2003, 2004
 *	Ohio University.
 *
 * ---
 * 
 * Starting with the release of tcptrace version 6 in 2001, tcptrace
 * is licensed under the GNU General Public License (GPL).  We believe
 * that, among the available licenses, the GPL will do the best job of
 * allowing tcptrace to continue to be a valuable, freely-available
 * and well-maintained tool for the networking community.
 *
 * Previous versions of tcptrace were released under a license that
 * was much less restrictive with respect to how tcptrace could be
 * used in commercial products.  Because of this, I am willing to
 * consider alternate license arrangements as allowed in Section 10 of
 * the GNU GPL.  Before I would consider licensing tcptrace under an
 * alternate agreement with a particular individual or company,
 * however, I would have to be convinced that such an alternative
 * would be to the greater benefit of the networking community.
 * 
 * ---
 *
 * This file is part of Tcptrace.
 *
 * Tcptrace was originally written and continues to be maintained by
 * Shawn Ostermann with the help of a group of devoted students and
 * users (see the file 'THANKS').  The work on tcptrace has been made
 * possible over the years through the generous support of NASA GRC,
 * the National Science Foundation, and Sun Microsystems.
 *
 * Tcptrace is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Tcptrace is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Tcptrace (in the file 'COPYING'); if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 * 
 * Author:	Shawn Ostermann
 * 		School of Electrical Engineering and Computer Science
 * 		Ohio University
 * 		Athens, OH
 *		ostermann@cs.ohiou.edu
 *		http://www.tcptrace.org/
 */
#include "tcptrace.h"
static char const GCC_UNUSED copyright[] =
    "@(#)Copyright (c) 2004 -- Ohio University.\n";
static char const GCC_UNUSED rcsid[] =
    "@(#)$Header$";

#include "gcache.h"

/* locally global variables */
static int packet_count = 0;
static int search_count = 0;
static Bool *ignore_pairs = NULL;/* which ones will we ignore */
static Bool more_conns_ignored = FALSE;



/* provided globals  */
int num_udp_pairs = -1;	/* how many pairs we've allocated */
udp_pair **utp = NULL;	/* array of pointers to allocated pairs */
int max_udp_pairs = 64; /* initial value, automatically increases */
u_long udp_trace_count = 0;


/* local routine definitions */
static udp_pair *NewUTP(struct ip *, struct udphdr *);
static udp_pair *FindUTP(struct ip *, struct udphdr *, int *);
static void MoreUdpPairs(int num_needed);




static udp_pair *
NewUTP(
    struct ip *pip,
    struct udphdr *pudp)
{
    udp_pair *pup;

    if (0) {
	 printf("trace.c:NewUTP() calling MakeUdpPair()\n");
    }
    pup = MakeUdpPair();
    ++num_udp_pairs;
    /* make a new one, if possible */
    if ((num_udp_pairs+1) >= max_udp_pairs) {
	MoreUdpPairs(num_udp_pairs+1);
    }

    /* create a new UDP pair record and remember where you put it */
    utp[num_udp_pairs] = pup;
    pup->ignore_pair=ignore_pairs[num_udp_pairs];


    /* grab the address from this packet */
    CopyAddr(&pup->addr_pair,
	     pip, ntohs(pudp->uh_sport), ntohs(pudp->uh_dport));

    /* data structure setup */
    pup->a2b.pup = pup;
    pup->b2a.pup = pup;
    pup->a2b.ptwin = &pup->b2a;
    pup->b2a.ptwin = &pup->a2b;

    /* fill in connection name fields */
    pup->a2b.host_letter = strdup(NextHostLetter());
    pup->b2a.host_letter = strdup(NextHostLetter());
    pup->a_hostname = strdup(HostName(pup->addr_pair.a_address));
    pup->a_portname = strdup(ServiceName(pup->addr_pair.a_port));
    pup->a_endpoint =
	strdup(EndpointName(pup->addr_pair.a_address,
			    pup->addr_pair.a_port));
    pup->b_hostname = strdup(HostName(pup->addr_pair.b_address));
    pup->b_portname = strdup(ServiceName(pup->addr_pair.b_port));
    pup->b_endpoint = 
	strdup(EndpointName(pup->addr_pair.b_address,
			    pup->addr_pair.b_port));

    pup->filename = cur_filename;

    return(pup);
}



/* connection records are stored in a hash table.  Buckets are linked	*/
/* lists sorted by most recent access.					*/
#define HASH_TABLE_SIZE 1021  /* oughta be prime */
static udp_pair *
FindUTP(
    struct ip *pip,
    struct udphdr *pudp,
    int *pdir)
{
    static udp_pair *pup_hashtable[HASH_TABLE_SIZE] = {NULL};
    udp_pair **ppup_head = NULL;
    udp_pair *pup;
    udp_pair *pup_last;
    udp_pair tp_in;
    int dir;
    hash hval;

    /* grab the address from this packet */
    CopyAddr(&tp_in.addr_pair, pip,
	     ntohs(pudp->uh_sport), ntohs(pudp->uh_dport));

    /* grab the hash value (already computed by CopyAddr) */
    hval = tp_in.addr_pair.hash % HASH_TABLE_SIZE;
    

    pup_last = NULL;
    ppup_head = &pup_hashtable[hval];
    for (pup = *ppup_head; pup; pup=pup->next) {
	++search_count;
	if (SameConn(&tp_in.addr_pair,&pup->addr_pair,&dir)) {
	    /* move to head of access list (unless already there) */
	    if (pup != *ppup_head) {
		pup_last->next = pup->next; /* unlink */
		pup->next = *ppup_head;	    /* move to head */
		*ppup_head = pup;
	    }
	    *pdir = dir;
	    return(pup);
	}
	pup_last = pup;
    }

    /* Didn't find it, make a new one, if possible */
    pup = NewUTP(pip,pudp);

    /* put at the head of the access list */
    if (pup) {
	pup->next = *ppup_head;
	*ppup_head = pup;
    }

    *pdir = A2B;
    return(pup);
}
     
void IgnoreUDPConn(
		   int ix)
{
   if (debug)
     fprintf(stderr,"ignoring conn %d\n", ix);
   
   --ix;
   
   MoreUdpPairs(ix);
   
   more_conns_ignored=FALSE;
   ignore_pairs[ix]=TRUE;
}

void 
OnlyUDPConn(
	    int ix_only)
{
     int ix;
     static Bool cleared = FALSE;
	
     if (debug) fprintf(stderr,"only printing conn %d\n", ix_only);

     --ix_only;

     MoreUdpPairs(ix_only);

     if (!cleared) {
	  for (ix = 0; ix < max_udp_pairs; ++ix) {
	       ignore_pairs[ix] = TRUE;
	  }
	  cleared = TRUE;
     }

     more_conns_ignored = TRUE;
     ignore_pairs[ix_only] = FALSE;  
}
 

udp_pair *
udpdotrace(
    struct ip *pip,
    struct udphdr *pudp,
    void *plast)
{
    udp_pair	*pup_save;
    ucb		*thisdir;
    ucb		*otherdir;
    udp_pair	tp_in;
    int		dir;
    u_short	uh_sport;	/* source port */
    u_short	uh_dport;	/* destination port */
    u_short	uh_ulen;	/* data length */

    /* make sure we have enough of the packet */
    if ((char *)pudp + sizeof(struct udphdr)-1 > (char *)plast) {
	if (warn_printtrunc)
	    fprintf(stderr,
		    "UDP packet %lu truncated too short to trace, ignored\n",
		    pnum);
	++ctrunc;
	return(NULL);
    }


    /* convert interesting fields to local byte order */
    uh_sport = ntohs(pudp->uh_sport);
    uh_dport = ntohs(pudp->uh_dport);
    uh_ulen = ntohs(pudp->uh_ulen);

    /* make sure this is one of the connections we want */
    pup_save = FindUTP(pip,pudp,&dir);

    ++packet_count;

    if (pup_save == NULL) {
	return(NULL);
    }

    ++udp_trace_count;

    /* do time stats */
    if (ZERO_TIME(&pup_save->first_time)) {
	pup_save->first_time = current_time;
    }
    pup_save->last_time = current_time;

    // Lets not waste any more CPU cycles if we are ignoring this connection.
    if (pup_save->ignore_pair)
	  return (pup_save);
     
    /* save to a file if requested */
    if (output_filename) {
	PcapSavePacket(output_filename,pip,plast);
    }

    /* now, print it if requested */
    if (printem && !printallofem) {
	printf("Packet %lu\n", pnum);
	printpacket(0,		/* original length not available */
		    (char *)plast - (char *)pip + 1,
		    NULL,0,	/* physical stuff not known here */
		    pip,plast,NULL);
    }

    /* grab the address from this packet */
    CopyAddr(&tp_in.addr_pair, pip,
	     uh_sport, uh_dport);

    /* figure out which direction this packet is going */
    if (dir == A2B) {
	thisdir  = &pup_save->a2b;
	otherdir = &pup_save->b2a;
    } else {
	thisdir  = &pup_save->b2a;
	otherdir = &pup_save->a2b;
    }


    /* do data stats */
    thisdir->packets += 1;
    thisdir->data_bytes += uh_ulen;


    /* total packets stats */
    ++pup_save->packets;

    return(pup_save);
}



void
udptrace_done(void)
{
    udp_pair *pup;
    int ix;
    double etime;

    if(do_udp) { // Just a quick sanity check to make sure if we need to do 
	         // anything at all..
	 if(!run_continuously) {
	      if (!printsuppress) {
		   if (udp_trace_count == 0) {
			fprintf(stdout,"no traced UDP packets\n");
			return;
		   } else {
			if ((tcp_trace_count > 0) && (!printbrief))
			     printf("\n============================================================\n");
			fprintf(stdout,"UDP connection info:\n");
		   }
	      }
	      
	      if (!printbrief)
		   fprintf(stdout,"%d UDP %s traced:\n",
			   num_udp_pairs + 1,
			   num_udp_pairs==0?"connection":"connections");
	 }
	 
	 /* elapsed time */
	 etime = elapsed(first_packet,last_packet);
	 
	 if (ctrunc > 0) {
	      fprintf(stdout,
		      "*** %lu packets were too short to process at some point\n",
		      ctrunc);
	      if (!warn_printtrunc)
		   fprintf(stdout,"\t(use -w option to show details)\n");
	 }
	 if (debug>1)
	      fprintf(stdout,"average search length: %d\n",
		      search_count / packet_count);
	 
	 /* print each connection */
	 if(!run_continuously) {
	      if (!printsuppress) {
		   for (ix = 0; ix <= num_udp_pairs; ++ix) {
			pup = utp[ix];
			if (!pup->ignore_pair) {
			     if (printbrief) {
				  fprintf(stdout,"%3d: ", ix+1);
				  UDPPrintBrief(pup);
			     } else {
				  if (ix > 0)
				       fprintf(stdout,
					       "================================\n");
				  fprintf(stdout,"UDP connection %d:\n", ix+1);
				  UDPPrintTrace(pup);
			     }
			}
		   }
	      }
	 }
    }
}
static void
MoreUdpPairs(
    int num_needed)
{
    int new_max_udp_pairs;
    int i;

    if (num_needed < max_udp_pairs)
	return;

    new_max_udp_pairs = max_udp_pairs * 4;
    while (new_max_udp_pairs < num_needed)
	new_max_udp_pairs *= 4;
    
    if (debug)
	printf("trace: making more space for %d total UDP pairs\n",
	       new_max_udp_pairs);

    /* enlarge array to hold any pairs that we might create */
    utp = ReallocZ(utp,
		   max_udp_pairs * sizeof(udp_pair *),
		   new_max_udp_pairs * sizeof(udp_pair *));

    /* enlarge array to keep track of which ones to ignore */
    ignore_pairs = ReallocZ(ignore_pairs,
			    max_udp_pairs * sizeof(Bool),
			    new_max_udp_pairs * sizeof(Bool));
    if (more_conns_ignored)
	for (i=max_udp_pairs; i < new_max_udp_pairs;++i)
	    ignore_pairs[i] = TRUE;

    max_udp_pairs = new_max_udp_pairs;
}


void
udptrace_init(void)
{
    static Bool initted = FALSE;

    if (initted)
	return;

    initted = TRUE;

    /* create an array to hold any pairs that we might create */
    utp = (udp_pair **) MallocZ(max_udp_pairs * sizeof(udp_pair *));

    /* create an array to keep track of which ones to ignore */
    ignore_pairs = (Bool *) MallocZ(max_udp_pairs * sizeof(Bool));
}