コード例 #1
0
ファイル: ipv4.c プロジェクト: panyfx/ath
int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
	struct inet_request_sock *ireq;
	struct request_sock *req;
	struct dccp_request_sock *dreq;
	const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);

	/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
		return 0;	/* discard, don't send a reset here */

	if (dccp_bad_service_code(sk, service)) {
		dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
		goto drop;
	}
	/*
	 * TW buckets are converted to open requests without
	 * limitations, they conserve resources and peer is
	 * evidently real one.
	 */
	dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
	if (inet_csk_reqsk_queue_is_full(sk))
		goto drop;

	/*
	 * Accept backlog is full. If we have already queued enough
	 * of warm entries in syn queue, drop request. It is better than
	 * clogging syn queue with openreqs with exponentially increasing
	 * timeout.
	 */
	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
		goto drop;

	req = inet_reqsk_alloc(&dccp_request_sock_ops, sk, true);
	if (req == NULL)
		goto drop;

	if (dccp_reqsk_init(req, dccp_sk(sk), skb))
		goto drop_and_free;

	dreq = dccp_rsk(req);
	if (dccp_parse_options(sk, dreq, skb))
		goto drop_and_free;

	if (security_inet_conn_request(sk, skb, req))
		goto drop_and_free;

	ireq = inet_rsk(req);
	sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
	sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
	ireq->ireq_family = AF_INET;
	ireq->ir_iif = sk->sk_bound_dev_if;

	/*
	 * Step 3: Process LISTEN state
	 *
	 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
	 *
	 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
	 */
	dreq->dreq_isr	   = dcb->dccpd_seq;
	dreq->dreq_gsr	   = dreq->dreq_isr;
	dreq->dreq_iss	   = dccp_v4_init_sequence(skb);
	dreq->dreq_gss     = dreq->dreq_iss;
	dreq->dreq_service = service;

	if (dccp_v4_send_response(sk, req))
		goto drop_and_free;

	inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
	return 0;

drop_and_free:
	reqsk_free(req);
drop:
	DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
	return -1;
}
コード例 #2
0
ファイル: ipv4.c プロジェクト: FatSunHYS/OSCourseDesign
int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
	struct inet_request_sock *ireq;
	struct dccp_sock dp;
	struct request_sock *req;
	struct dccp_request_sock *dreq;
	const __be32 saddr = skb->nh.iph->saddr;
	const __be32 daddr = skb->nh.iph->daddr;
 	const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
	__u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;

	/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
	if (((struct rtable *)skb->dst)->rt_flags &
	    (RTCF_BROADCAST | RTCF_MULTICAST)) {
		reset_code = DCCP_RESET_CODE_NO_CONNECTION;
		goto drop;
	}

	if (dccp_bad_service_code(sk, service)) {
		reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
		goto drop;
 	}
	/*
	 * TW buckets are converted to open requests without
	 * limitations, they conserve resources and peer is
	 * evidently real one.
	 */
	if (inet_csk_reqsk_queue_is_full(sk))
		goto drop;

	/*
	 * Accept backlog is full. If we have already queued enough
	 * of warm entries in syn queue, drop request. It is better than
	 * clogging syn queue with openreqs with exponentially increasing
	 * timeout.
	 */
	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
		goto drop;

	req = reqsk_alloc(sk->sk_prot->rsk_prot);
	if (req == NULL)
		goto drop;

	if (dccp_parse_options(sk, skb))
		goto drop_and_free;

	dccp_openreq_init(req, &dp, skb);

	ireq = inet_rsk(req);
	ireq->loc_addr = daddr;
	ireq->rmt_addr = saddr;
	req->rcv_wnd	= dccp_feat_default_sequence_window;
	ireq->opt	= NULL;

	/* 
	 * Step 3: Process LISTEN state
	 *
	 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
	 *
	 * In fact we defer setting S.GSR, S.SWL, S.SWH to
	 * dccp_create_openreq_child.
	 */
	dreq = dccp_rsk(req);
	dreq->dreq_isr	   = dcb->dccpd_seq;
	dreq->dreq_iss	   = dccp_v4_init_sequence(sk, skb);
	dreq->dreq_service = service;

	if (dccp_v4_send_response(sk, req, NULL))
		goto drop_and_free;

	inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
	return 0;

drop_and_free:
	reqsk_free(req);
drop:
	DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
	dcb->dccpd_reset_code = reset_code;
	return -1;
}