Function pfsync_input

freebsd/netpfil/pf/if_pfsync.c:641–745

}

static int
pfsync_input(struct mbuf **mp, int *offp __unused, int proto __unused)
{
	struct pfsync_softc *sc = V_pfsyncif;
	struct pfsync_pkt pkt;
	struct mbuf *m = *mp;
	struct ip *ip = mtod(m, struct ip *);
	struct pfsync_header *ph;
	struct pfsync_subheader subh;

	int offset, len;
	int rv;
	uint16_t count;

	PF_RULES_RLOCK_TRACKER;

	*mp = NULL;
	V_pfsyncstats.pfsyncs_ipackets++;

	/* Verify that we have a sync interface configured. */
	if (!sc || !sc->sc_sync_if || !V_pf_status.running ||
	    (sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
		goto done;

	/* verify that the packet came in on the right interface */
	if (sc->sc_sync_if != m->m_pkthdr.rcvif) {
		V_pfsyncstats.pfsyncs_badif++;
		goto done;
	}

	if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
	if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
	/* verify that the IP TTL is 255. */
	if (ip->ip_ttl != PFSYNC_DFLTTL) {
		V_pfsyncstats.pfsyncs_badttl++;
		goto done;
	}

	offset = ip->ip_hl << 2;
	if (m->m_pkthdr.len < offset + sizeof(*ph)) {
		V_pfsyncstats.pfsyncs_hdrops++;
		goto done;
	}

	if (offset + sizeof(*ph) > m->m_len) {
		if (m_pullup(m, offset + sizeof(*ph)) == NULL) {
			V_pfsyncstats.pfsyncs_hdrops++;
			return (IPPROTO_DONE);
		}
		ip = mtod(m, struct ip *);
	}
	ph = (struct pfsync_header *)((char *)ip + offset);

	/* verify the version */
	if (ph->version != PFSYNC_VERSION) {
		V_pfsyncstats.pfsyncs_badver++;
		goto done;
	}