gre.c

来自「Firestorm NIDS是一个性能非常高的网络入侵检测系统 (NIDS)。目」· C语言 代码 · 共 80 行

#include <stdlib.h>

#include <firestorm.h>
#include <packet.h>
#include <args.h>
#include <plugin.h>
#include <alert.h>
#include <signature.h>
#include <decode.h>
#include <preproc.h>

PLUGIN_STD_DEFS();
proc_dispatch dispatch;

/* GRE: Generic routing encapsulation */
void gre_decode(struct packet *);
struct proto gre_p=init_proto("gre", gre_decode, NULL);
struct proto_req gre_r[]={
	proto_request("ip", 47),
	null_request()
};

void gre_decode(struct packet *p)
{
	struct proto_child *pc;
	struct layer *l=&p->layer[p->llen];

	if ( (p->layer[p->llen+1].h.raw=
		l->h.raw+sizeof(struct pkt_grehdr))
		> p->end ) return;

	p->llen++;

	if ( p->llen >= PKT_LAYERS ) return;

	for(pc=l->proto->children; pc; pc=pc->next)
	{
		if ( l->h.gre->proto == pc->id ) {
			p->layer[p->llen].flags=0;
			p->layer[p->llen].session=NULL;
			p->layer[p->llen].proto=pc->proto;
			pc->proto->decode(p);
			return;
		}
	}

	if ( p->layer[p->llen].h.raw<p->end )
		p->layer[p->llen++].proto=NULL;
	dispatch(p);
}

int PLUGIN_DECODE (struct decode_api *d)
{
	int ok=0;

	object_check(d);

	dispatch=d->dispatch;

	ok+=d->decode_add(&gre_p, gre_r);

	return (ok) ? PLUGIN_ERR_OK : PLUGIN_ERR_FAIL;
}

int PLUGIN_INIT (struct plugin_in *in, struct plugin_out *out)
{
	plugin_check(in, out);

	PLUGIN_ID("decode.gre", "Generic Routing Encapsulation");
	PLUGIN_VERSION(2, 0);
	PLUGIN_AUTHOR("Gianni Tedesco", "[e-mail]");
	PLUGIN_LICENSE("GPL");

	return PLUGIN_ERR_OK;
}

int PLUGIN_UNLOAD (int code) {
	return PLUGIN_ERR_OK;
}