vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
{
	int i;
	double now;

	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
	CHECK_OBJ_NOTNULL(bo, BUSYOBJ_MAGIC);

	AZ(bo->storage);
	AZ(bo->storage_hint);

	bo->storage = STV_next();

	if (bo->retries > 0)
		http_Unset(bo->bereq, "\012X-Varnish:");

	http_PrintfHeader(bo->bereq, "X-Varnish: %u", VXID(bo->vsl->wid));

	VCL_backend_fetch_method(bo->vcl, wrk, NULL, bo, NULL);

	bo->uncacheable = bo->do_pass;
	if (wrk->handling == VCL_RET_ABANDON || wrk->handling == VCL_RET_FAIL)
		return (F_STP_FAIL);

	assert (wrk->handling == VCL_RET_FETCH);

	HTTP_Setup(bo->beresp, bo->ws, bo->vsl, SLT_BerespMethod);

	assert(bo->fetch_objcore->boc->state <= BOS_REQ_DONE);

	AZ(bo->htc);
	i = VDI_GetHdr(wrk, bo);

	now = W_TIM_real(wrk);
	VSLb_ts_busyobj(bo, "Beresp", now);

	if (i) {
		assert(bo->director_state == DIR_S_NULL);
		return (F_STP_ERROR);
	}

	http_VSL_log(bo->beresp);

	if (!http_GetHdr(bo->beresp, H_Date, NULL)) {
		/*
		 * RFC 2616 14.18 Date: The Date general-header field
		 * represents the date and time at which the message was
		 * originated, having the same semantics as orig-date in
		 * RFC 822. ... A received message that does not have a
		 * Date header field MUST be assigned one by the recipient
		 * if the message will be cached by that recipient or
		 * gatewayed via a protocol which requires a Date.
		 *
		 * If we didn't get a Date header, we assign one here.
		 */
		http_TimeHeader(bo->beresp, "Date: ", now);
	}

	/*
	 * These two headers can be spread over multiple actual headers
	 * and we rely on their content outside of VCL, so collect them
	 * into one line here.
	 */
	http_CollectHdr(bo->beresp, H_Cache_Control);
	http_CollectHdr(bo->beresp, H_Vary);

	/*
	 * Figure out how the fetch is supposed to happen, before the
	 * headers are adultered by VCL
	 */
	if (!strcasecmp(http_GetMethod(bo->bereq), "head")) {
		/*
		 * A HEAD request can never have a body in the reply,
		 * no matter what the headers might say.
		 * [RFC7231 4.3.2 p25]
		 */
		wrk->stats->fetch_head++;
		bo->htc->body_status = BS_NONE;
	} else if (http_GetStatus(bo->beresp) <= 199) {
		/*
		 * 1xx responses never have a body.
		 * [RFC7230 3.3.2 p31]
		 * ... but we should never see them.
		 */
		wrk->stats->fetch_1xx++;
		bo->htc->body_status = BS_ERROR;
	} else if (http_IsStatus(bo->beresp, 204)) {
		/*
		 * 204 is "No Content", obviously don't expect a body.
		 * [RFC7230 3.3.1 p29 and 3.3.2 p31]
		 */
		wrk->stats->fetch_204++;
		if ((http_GetHdr(bo->beresp, H_Content_Length, NULL) &&
		    bo->htc->content_length != 0) ||
		    http_GetHdr(bo->beresp, H_Transfer_Encoding, NULL))
			bo->htc->body_status = BS_ERROR;
		else
			bo->htc->body_status = BS_NONE;
	} else if (http_IsStatus(bo->beresp, 304)) {
		/*
		 * 304 is "Not Modified" it has no body.
		 * [RFC7230 3.3 p28]
		 */
		wrk->stats->fetch_304++;
		bo->htc->body_status = BS_NONE;
	} else if (bo->htc->body_status == BS_CHUNKED) {
		wrk->stats->fetch_chunked++;
	} else if (bo->htc->body_status == BS_LENGTH) {
		assert(bo->htc->content_length > 0);
		wrk->stats->fetch_length++;
	} else if (bo->htc->body_status == BS_EOF) {
		wrk->stats->fetch_eof++;
	} else if (bo->htc->body_status == BS_ERROR) {
		wrk->stats->fetch_bad++;
	} else if (bo->htc->body_status == BS_NONE) {
		wrk->stats->fetch_none++;
	} else {
		WRONG("wrong bodystatus");
	}

	if (bo->htc->body_status == BS_ERROR) {
		bo->htc->doclose = SC_RX_BODY;
		VDI_Finish(bo->wrk, bo);
		VSLb(bo->vsl, SLT_Error, "Body cannot be fetched");
		assert(bo->director_state == DIR_S_NULL);
		return (F_STP_ERROR);
	}

	if (bo->fetch_objcore->flags & OC_F_PRIVATE) {
		/* private objects have negative TTL */
		bo->fetch_objcore->t_origin = now;
		bo->fetch_objcore->ttl = -1.;
		bo->fetch_objcore->grace = 0;
		bo->fetch_objcore->keep = 0;
	} else {
		/* What does RFC2616 think about TTL ? */
		RFC2616_Ttl(bo, now,
		    &bo->fetch_objcore->t_origin,
		    &bo->fetch_objcore->ttl,
		    &bo->fetch_objcore->grace,
		    &bo->fetch_objcore->keep
		    );
	}

	AZ(bo->do_esi);
	AZ(bo->was_304);

	if (http_IsStatus(bo->beresp, 304)) {
		if (bo->stale_oc != NULL &&
		    ObjCheckFlag(bo->wrk, bo->stale_oc, OF_IMSCAND)) {
			if (ObjCheckFlag(bo->wrk, bo->stale_oc, OF_CHGGZIP)) {
				/*
				 * If we changed the gzip status of the object
				 * the stored Content_Encoding controls we
				 * must weaken any new ETag we get.
				 */
				http_Unset(bo->beresp, H_Content_Encoding);
				RFC2616_Weaken_Etag(bo->beresp);
			}
			http_Unset(bo->beresp, H_Content_Length);
			HTTP_Merge(bo->wrk, bo->stale_oc, bo->beresp);
			assert(http_IsStatus(bo->beresp, 200));
			bo->was_304 = 1;
		} else if (!bo->do_pass) {
			/*
			 * Backend sent unallowed 304
			 */
			VSLb(bo->vsl, SLT_Error,
			    "304 response but not conditional fetch");
			bo->htc->doclose = SC_RX_BAD;
			VDI_Finish(bo->wrk, bo);
			return (F_STP_ERROR);
		}
	}

	bo->vfc->bo = bo;
	bo->vfc->oc = bo->fetch_objcore;
	bo->vfc->wrk = bo->wrk;
	bo->vfc->http = bo->beresp;
	bo->vfc->esi_req = bo->bereq;

	VCL_backend_response_method(bo->vcl, wrk, NULL, bo, NULL);

	if (wrk->handling == VCL_RET_ABANDON || wrk->handling == VCL_RET_FAIL) {
		bo->htc->doclose = SC_RESP_CLOSE;
		VDI_Finish(bo->wrk, bo);
		return (F_STP_FAIL);
	}

	if (wrk->handling == VCL_RET_RETRY) {
		if (bo->htc->body_status != BS_NONE)
			bo->htc->doclose = SC_RESP_CLOSE;
		if (bo->director_state != DIR_S_NULL)
			VDI_Finish(bo->wrk, bo);

		if (bo->retries++ < cache_param->max_retries)
			return (F_STP_RETRY);

		VSLb(bo->vsl, SLT_VCL_Error,
		    "Too many retries, delivering 503");
		assert(bo->director_state == DIR_S_NULL);
		return (F_STP_ERROR);
	}

	assert(bo->fetch_objcore->boc->state <= BOS_REQ_DONE);
	if (bo->fetch_objcore->boc->state != BOS_REQ_DONE) {
		bo->req = NULL;
		ObjSetState(wrk, bo->fetch_objcore, BOS_REQ_DONE);
	}

	if (bo->do_esi)
		bo->do_stream = 0;
	if (wrk->handling == VCL_RET_PASS) {
		bo->fetch_objcore->flags |= OC_F_HFP;
		bo->uncacheable = 1;
		wrk->handling = VCL_RET_DELIVER;
	}
	if (bo->do_pass || bo->uncacheable)
		bo->fetch_objcore->flags |= OC_F_PASS;

	assert(wrk->handling == VCL_RET_DELIVER);

	return (bo->was_304 ? F_STP_CONDFETCH : F_STP_FETCH);
}