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/* David Leonard, 2002. Public domain. */
/* $Id: flow.c 1199 2008-02-29 16:11:24Z d $ */
/*
* A flow is a grouped history of packets with some similarity.
* Each flow is uniquely identified by a 'tag', which is
* descriptive string. Some flows have extra descriptive
* information, like FTP transferred file names. Flow data
* structures are supposed to hang around for a while, even
* if no packet activity in that flow has been seen.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#if STDC_HEADERS
# include <string.h>
# include <stdlib.h>
#endif
#if HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
#include "compat.h"
#include "flow.h"
int nflows = 0;
struct flow *flows;
static int maxflows = 0;
/* Generate a hash value for a tag */
static unsigned int
hash(const char *tag)
{
unsigned int result;
for (result = 0; *tag; tag++)
result = (result << 1) ^ *tag;
return result;
}
#define MAXFLOWS 1024
/* Find a flow by its tag */
struct flow *
findflow(const char *tag)
{
int i;
unsigned int taghash = hash(tag);
for (i = 0; i < nflows; i++)
if (flows[i].taghash == taghash
&& strcmp(flows[i].tag, tag) == 0)
return &flows[i];
if (nflows >= maxflows) {
if (maxflows == 0) {
maxflows = 8;
flows = (struct flow *)malloc(maxflows * sizeof *flows);
} else if (maxflows < MAXFLOWS) {
if (maxflows * 2 <= MAXFLOWS)
maxflows *= 2;
else
maxflows = MAXFLOWS;
flows = (struct flow *)realloc(flows,
maxflows * sizeof *flows);
} else {
flow_del(&flows[nflows - 1]);
}
if (flows == NULL)
errx(1, "malloc/realloc");
}
flows[nflows].taghash = taghash;
strlcpy(flows[nflows].tag, tag, sizeof flows[nflows].tag);
flows[nflows].desc[0] = '\0';
flows[nflows].octets = 0;
flows[nflows].total_octets = 0;
flows[nflows].packets = 0;
flows[nflows].total_packets = 0;
flows[nflows].keepalive = -1;
flows[nflows].dontdel = 0;
flows[nflows].udata = NULL;
flows[nflows].freeudata = NULL;
return &flows[nflows++];
}
/* Compare flows by the number of octets they have carried (reverse order) */
int
octetcmp(const void *a, const void *b)
{
const struct flow *fa = (const struct flow *)a;
const struct flow *fb = (const struct flow *)b;
return -(fa->octets - fb->octets);
}
/* Compare flows by their tag */
int
tagcmp( const void *a, const void *b)
{
const struct flow *fa = (const struct flow *)a;
const struct flow *fb = (const struct flow *)b;
return strcmp(fa->tag, fb->tag);
}
/* Compare flows by the time they were last seen (reverse order) */
int
lastcmp(const void *a, const void *b)
{
const struct flow *fa = (const struct flow *)a;
const struct flow *fb = (const struct flow *)b;
if (fb->lastseen.tv_sec - fa->lastseen.tv_sec == 0)
if (fb->lastseen.tv_usec - fa->lastseen.tv_usec == 0)
return tagcmp(a, b);
else
return fb->lastseen.tv_usec - fa->lastseen.tv_usec;
else
return fb->lastseen.tv_sec - fa->lastseen.tv_sec;
}
/* Compare flows by their packet count (reverse order) */
int
packetcmp(const void *a, const void *b)
{
const struct flow *fa = (const struct flow *)a;
const struct flow *fb = (const struct flow *)b;
return fa->packets - fb->packets;
}
/* Zero the octet count on all flows */
void
flow_zero()
{
int i;
for (i = 0; i < nflows; i++) {
flows[i].octets = 0;
flows[i].packets = 0;
}
}
/* Remove a flow */
void
flow_del(struct flow *f)
{
int i = f - flows;
if (f->freeudata)
(*f->freeudata)(f->udata);
if (nflows > 1 && i != nflows -1) {
memcpy(f, &flows[nflows-1], sizeof (struct flow));
}
nflows--;
}
void
flow_free()
{
while (nflows)
flow_del(flows + nflows - 1);
if (maxflows) {
free(flows);
maxflows = 0;
}
}
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