src/fragroute/fragroute.c
/*
* fragroute.c
*
* Copyright (c) 2001 Dug Song <dugsong@monkey.org>
* Copyright (c) 2007-2008 Aaron Turner.
* Copyright (c) 2013-2022 Fred Klassen - AppNeta
* $Id$
*/
#include "defines.h"
#include "config.h"
#include "common.h"
#include "lib/queue.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_LIBDNET
/* need to undef these which are pulled in via defines.h, prior to importing dnet.h */
#undef icmp_id
#undef icmp_seq
#undef icmp_data
#undef icmp_mask
#ifdef HAVE_DNET_H
#include <dnet.h>
#endif
#ifdef HAVE_DUMBNET_H
#include <dumbnet.h>
#endif
#endif
#include "fragroute.h"
#include "mod.h"
#include "pkt.h"
void
fragroute_close(fragroute_t *ctx)
{
assert(ctx);
free(ctx->pktq);
free(ctx);
pkt_close();
}
int
fragroute_process(fragroute_t *ctx, void *buf, size_t len)
{
struct pkt *pkt;
assert(ctx);
assert(buf);
ctx->first_packet = 0;
/* save the l2 header of the original packet for later */
ctx->l2len = get_l2len(buf, (int)len, ctx->dlt);
memcpy(ctx->l2header, buf, ctx->l2len);
if ((pkt = pkt_new(len)) == NULL) {
strcpy(ctx->errbuf, "unable to pkt_new()");
return -1;
}
memcpy(pkt->pkt_data, buf, len);
pkt->pkt_end = pkt->pkt_data + len;
pkt_decorate(pkt);
if (pkt->pkt_ip == NULL) {
strcpy(ctx->errbuf, "skipping non-IP packet");
return -1;
}
/* Don't always checksum packets before being fragged
if (pkt->pkt_eth && htons(pkt->pkt_eth->eth_type) == ETH_TYPE_IP) {
ip_checksum(pkt->pkt_ip, len);
}
*/
TAILQ_INIT(ctx->pktq);
TAILQ_INSERT_TAIL(ctx->pktq, pkt, pkt_next);
mod_apply(ctx->pktq);
return 0;
}
/*
* keep calling this after fragroute_process() to get all the fragments.
* Each call returns the fragment length which is stored in **packet.
* Returns 0 when no more fragments remain or -1 on error
*/
int
fragroute_getfragment(fragroute_t *ctx, char **packet)
{
static struct pkt *pkt = NULL;
static struct pkt *next = NULL;
char *pkt_data = *packet;
u_int32_t length;
if (ctx->first_packet != 0) {
pkt = next;
} else {
ctx->first_packet = 1;
pkt = TAILQ_FIRST(ctx->pktq);
}
if (pkt != TAILQ_END(&(ctx->pktq))) {
next = TAILQ_NEXT(pkt, pkt_next);
memcpy(pkt_data, pkt->pkt_data, pkt->pkt_end - pkt->pkt_data);
/* return the original L2 header */
memcpy(pkt_data, ctx->l2header, ctx->l2len);
length = pkt->pkt_end - pkt->pkt_data;
pkt = next;
return (int)length;
}
return 0; // nothing
}
fragroute_t *
fragroute_init(const int mtu, const int dlt, const char *config, char *errbuf)
{
fragroute_t *ctx;
if (dlt != DLT_EN10MB) {
sprintf(errbuf, "Fragroute only supports DLT_EN10MB pcap files");
return NULL;
}
ctx = (fragroute_t *)safe_malloc(sizeof(fragroute_t));
ctx->pktq = (struct pktq *)safe_malloc(sizeof(struct pktq));
ctx->dlt = dlt;
pkt_init(128);
ctx->mtu = mtu;
/* parse the config */
if (mod_open(config, errbuf) < 0) {
fragroute_close(ctx);
return NULL;
}
return ctx;
}