#include "ccid.h"
#include "dccp.h"
-static void dccp_fin(struct sock *sk, struct sk_buff *skb)
+/* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */
+int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8;
+
+static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb)
{
- sk->sk_shutdown |= RCV_SHUTDOWN;
- sock_set_flag(sk, SOCK_DONE);
__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
__skb_queue_tail(&sk->sk_receive_queue, skb);
skb_set_owner_r(skb, sk);
sk->sk_data_ready(sk, 0);
}
-static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
+static void dccp_fin(struct sock *sk, struct sk_buff *skb)
{
- dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
- dccp_fin(sk, skb);
- dccp_set_state(sk, DCCP_CLOSED);
- sk_wake_async(sk, 1, POLL_HUP);
+ /*
+ * On receiving Close/CloseReq, both RD/WR shutdown are performed.
+ * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after
+ * receiving the closing segment, but there is no guarantee that such
+ * data will be processed at all.
+ */
+ sk->sk_shutdown = SHUTDOWN_MASK;
+ sock_set_flag(sk, SOCK_DONE);
+ dccp_enqueue_skb(sk, skb);
}
-static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
+static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
{
+ int queued = 0;
+
+ switch (sk->sk_state) {
+ /*
+ * We ignore Close when received in one of the following states:
+ * - CLOSED (may be a late or duplicate packet)
+ * - PASSIVE_CLOSEREQ (the peer has sent a CloseReq earlier)
+ * - RESPOND (already handled by dccp_check_req)
+ */
+ case DCCP_CLOSING:
+ /*
+ * Simultaneous-close: receiving a Close after sending one. This
+ * can happen if both client and server perform active-close and
+ * will result in an endless ping-pong of crossing and retrans-
+ * mitted Close packets, which only terminates when one of the
+ * nodes times out (min. 64 seconds). Quicker convergence can be
+ * achieved when one of the nodes acts as tie-breaker.
+ * This is ok as both ends are done with data transfer and each
+ * end is just waiting for the other to acknowledge termination.
+ */
+ if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT)
+ break;
+ /* fall through */
+ case DCCP_REQUESTING:
+ case DCCP_ACTIVE_CLOSEREQ:
+ dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
+ dccp_done(sk);
+ break;
+ case DCCP_OPEN:
+ case DCCP_PARTOPEN:
+ /* Give waiting application a chance to read pending data */
+ queued = 1;
+ dccp_fin(sk, skb);
+ dccp_set_state(sk, DCCP_PASSIVE_CLOSE);
+ /* fall through */
+ case DCCP_PASSIVE_CLOSE:
+ /*
+ * Retransmitted Close: we have already enqueued the first one.
+ */
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ }
+ return queued;
+}
+
+static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
+{
+ int queued = 0;
+
/*
* Step 7: Check for unexpected packet types
* If (S.is_server and P.type == CloseReq)
*/
if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
- return;
+ return queued;
}
- if (sk->sk_state != DCCP_CLOSING)
+ /* Step 13: process relevant Client states < CLOSEREQ */
+ switch (sk->sk_state) {
+ case DCCP_REQUESTING:
+ dccp_send_close(sk, 0);
dccp_set_state(sk, DCCP_CLOSING);
- dccp_send_close(sk, 0);
+ break;
+ case DCCP_OPEN:
+ case DCCP_PARTOPEN:
+ /* Give waiting application a chance to read pending data */
+ queued = 1;
+ dccp_fin(sk, skb);
+ dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ);
+ /* fall through */
+ case DCCP_PASSIVE_CLOSEREQ:
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ }
+ return queued;
+}
+
+static u8 dccp_reset_code_convert(const u8 code)
+{
+ const u8 error_code[] = {
+ [DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */
+ [DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */
+ [DCCP_RESET_CODE_ABORTED] = ECONNRESET,
+
+ [DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED,
+ [DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED,
+ [DCCP_RESET_CODE_TOO_BUSY] = EUSERS,
+ [DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT,
+
+ [DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG,
+ [DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR,
+ [DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC,
+ [DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ,
+ [DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP,
+ };
+
+ return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code];
+}
+
+static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb)
+{
+ u8 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code);
+
+ sk->sk_err = err;
+
+ /* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */
+ dccp_fin(sk, skb);
+
+ if (err && !sock_flag(sk, SOCK_DEAD))
+ sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
+ dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
}
static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
- if (dccp_msk(sk)->dccpms_send_ack_vector)
+ if (dp->dccps_hc_rx_ackvec != NULL)
dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
DCCP_SKB_CB(skb)->dccpd_ack_seq);
}
+static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb)
+{
+ const struct dccp_sock *dp = dccp_sk(sk);
+
+ /* Don't deliver to RX CCID when node has shut down read end. */
+ if (!(sk->sk_shutdown & RCV_SHUTDOWN))
+ ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
+ /*
+ * Until the TX queue has been drained, we can not honour SHUT_WR, since
+ * we need received feedback as input to adjust congestion control.
+ */
+ if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN))
+ ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
+}
+
static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
struct dccp_sock *dp = dccp_sk(sk);
- u64 lswl, lawl;
+ u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq,
+ ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
/*
* Step 5: Prepare sequence numbers for Sync
*/
if (dh->dccph_type == DCCP_PKT_SYNC ||
dh->dccph_type == DCCP_PKT_SYNCACK) {
- if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
- dp->dccps_awl, dp->dccps_awh) &&
- !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
- dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
+ if (between48(ackno, dp->dccps_awl, dp->dccps_awh) &&
+ dccp_delta_seqno(dp->dccps_swl, seqno) >= 0)
+ dccp_update_gsr(sk, seqno);
else
return -1;
}
* Update S.GSR, S.SWL, S.SWH
* If P.type != Sync,
* Update S.GAR
- * Otherwise,
- * Send Sync packet acknowledging P.seqno
- * Drop packet and return
*/
lswl = dp->dccps_swl;
lawl = dp->dccps_awl;
if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
dh->dccph_type == DCCP_PKT_CLOSE ||
dh->dccph_type == DCCP_PKT_RESET) {
- lswl = dp->dccps_gsr;
- dccp_inc_seqno(&lswl);
+ lswl = ADD48(dp->dccps_gsr, 1);
lawl = dp->dccps_gar;
}
- if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
- (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
- between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
- lawl, dp->dccps_awh))) {
- dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
+ if (between48(seqno, lswl, dp->dccps_swh) &&
+ (ackno == DCCP_PKT_WITHOUT_ACK_SEQ ||
+ between48(ackno, lawl, dp->dccps_awh))) {
+ dccp_update_gsr(sk, seqno);
if (dh->dccph_type != DCCP_PKT_SYNC &&
- (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
- DCCP_PKT_WITHOUT_ACK_SEQ))
- dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
+ (ackno != DCCP_PKT_WITHOUT_ACK_SEQ))
+ dp->dccps_gar = ackno;
} else {
+ unsigned long now = jiffies;
+ /*
+ * Step 6: Check sequence numbers
+ * Otherwise,
+ * If P.type == Reset,
+ * Send Sync packet acknowledging S.GSR
+ * Otherwise,
+ * Send Sync packet acknowledging P.seqno
+ * Drop packet and return
+ *
+ * These Syncs are rate-limited as per RFC 4340, 7.5.4:
+ * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second.
+ */
+ if (time_before(now, (dp->dccps_rate_last +
+ sysctl_dccp_sync_ratelimit)))
+ return 0;
+
DCCP_WARN("DCCP: Step 6 failed for %s packet, "
"(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
"(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
"sending SYNC...\n", dccp_packet_name(dh->dccph_type),
- (unsigned long long) lswl,
- (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq,
+ (unsigned long long) lswl, (unsigned long long) seqno,
(unsigned long long) dp->dccps_swh,
- (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
- DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
- (unsigned long long) lawl,
- (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq,
+ (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist"
+ : "exists",
+ (unsigned long long) lawl, (unsigned long long) ackno,
(unsigned long long) dp->dccps_awh);
- dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
+
+ dp->dccps_rate_last = now;
+
+ if (dh->dccph_type == DCCP_PKT_RESET)
+ seqno = dp->dccps_gsr;
+ dccp_send_sync(sk, seqno, DCCP_PKT_SYNC);
return -1;
}
case DCCP_PKT_DATAACK:
case DCCP_PKT_DATA:
/*
- * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
- * option if it is.
+ * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when
+ * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening"
+ * - sk_receive_queue is full, use Code 2, "Receive Buffer"
*/
- __skb_pull(skb, dh->dccph_doff * 4);
- __skb_queue_tail(&sk->sk_receive_queue, skb);
- skb_set_owner_r(skb, sk);
- sk->sk_data_ready(sk, 0);
+ dccp_enqueue_skb(sk, skb);
return 0;
case DCCP_PKT_ACK:
goto discard;
* S.state := TIMEWAIT
* Set TIMEWAIT timer
* Drop packet and return
- */
- dccp_fin(sk, skb);
- dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
+ */
+ dccp_rcv_reset(sk, skb);
return 0;
case DCCP_PKT_CLOSEREQ:
- dccp_rcv_closereq(sk, skb);
+ if (dccp_rcv_closereq(sk, skb))
+ return 0;
goto discard;
case DCCP_PKT_CLOSE:
- dccp_rcv_close(sk, skb);
- return 0;
+ if (dccp_rcv_close(sk, skb))
+ return 0;
+ goto discard;
case DCCP_PKT_REQUEST:
/* Step 7
* or (S.is_server and P.type == Response)
if (dp->dccps_role != DCCP_ROLE_CLIENT)
goto send_sync;
check_seq:
- if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
+ if (dccp_delta_seqno(dp->dccps_osr,
+ DCCP_SKB_CB(skb)->dccpd_seq) >= 0) {
send_sync:
dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
DCCP_PKT_SYNC);
if (dccp_check_seqno(sk, skb))
goto discard;
- if (dccp_parse_options(sk, skb))
- goto discard;
+ if (dccp_parse_options(sk, NULL, skb))
+ return 1;
if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
dccp_event_ack_recv(sk, skb);
- if (dccp_msk(sk)->dccpms_send_ack_vector &&
+ if (dp->dccps_hc_rx_ackvec != NULL &&
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
DCCP_SKB_CB(skb)->dccpd_seq,
DCCP_ACKVEC_STATE_RECEIVED))
goto discard;
-
- /*
- * Deliver to the CCID module in charge.
- * FIXME: Currently DCCP operates one-directional only, i.e. a listening
- * server is not at the same time a connecting client. There is
- * not much sense in delivering to both rx/tx sides at the moment
- * (only one is active at a time); when moving to bidirectional
- * service, this needs to be revised.
- */
- if (dccp_sk(sk)->dccps_role == DCCP_ROLE_CLIENT)
- ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
- else /* listening or connected server */
- ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
+ dccp_deliver_input_to_ccids(sk, skb);
return __dccp_rcv_established(sk, skb, dh, len);
discard:
if (dh->dccph_type == DCCP_PKT_RESPONSE) {
const struct inet_connection_sock *icsk = inet_csk(sk);
struct dccp_sock *dp = dccp_sk(sk);
-
- /* Stop the REQUEST timer */
- inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
- BUG_TRAP(sk->sk_send_head != NULL);
- __kfree_skb(sk->sk_send_head);
- sk->sk_send_head = NULL;
+ long tstamp = dccp_timestamp();
if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
dp->dccps_awl, dp->dccps_awh)) {
goto out_invalid_packet;
}
- if (dccp_parse_options(sk, skb))
- goto out_invalid_packet;
+ /*
+ * If option processing (Step 8) failed, return 1 here so that
+ * dccp_v4_do_rcv() sends a Reset. The Reset code depends on
+ * the option type and is set in dccp_parse_options().
+ */
+ if (dccp_parse_options(sk, NULL, skb))
+ return 1;
- if (dccp_msk(sk)->dccpms_send_ack_vector &&
- dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
- DCCP_SKB_CB(skb)->dccpd_seq,
- DCCP_ACKVEC_STATE_RECEIVED))
- goto out_invalid_packet; /* FIXME: change error code */
+ /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
+ if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
+ dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
+ dp->dccps_options_received.dccpor_timestamp_echo));
+
+ /* Stop the REQUEST timer */
+ inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
+ WARN_ON(sk->sk_send_head == NULL);
+ kfree_skb(sk->sk_send_head);
+ sk->sk_send_head = NULL;
dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
dccp_update_gsr(sk, dp->dccps_isr);
*/
dccp_set_state(sk, DCCP_PARTOPEN);
+ /*
+ * If feature negotiation was successful, activate features now;
+ * an activation failure means that this host could not activate
+ * one ore more features (e.g. insufficient memory), which would
+ * leave at least one feature in an undefined state.
+ */
+ if (dccp_feat_activate_values(sk, &dp->dccps_featneg))
+ goto unable_to_proceed;
+
/* Make sure socket is routed, for correct metrics. */
icsk->icsk_af_ops->rebuild_header(sk);
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_state_change(sk);
- sk_wake_async(sk, 0, POLL_OUT);
+ sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
}
if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
/* dccp_v4_do_rcv will send a reset */
DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
return 1;
+
+unable_to_proceed:
+ DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED;
+ /*
+ * We mark this socket as no longer usable, so that the loop in
+ * dccp_sendmsg() terminates and the application gets notified.
+ */
+ dccp_set_state(sk, DCCP_CLOSED);
+ sk->sk_err = ECOMM;
+ return 1;
}
static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
skb) < 0)
return 1;
-
- /* FIXME: do congestion control initialization */
goto discard;
}
if (dh->dccph_type == DCCP_PKT_RESET)
return 1;
}
- if (sk->sk_state != DCCP_REQUESTING) {
+ if (sk->sk_state != DCCP_REQUESTING && sk->sk_state != DCCP_RESPOND) {
if (dccp_check_seqno(sk, skb))
goto discard;
/*
* Step 8: Process options and mark acknowledgeable
*/
- if (dccp_parse_options(sk, skb))
- goto discard;
+ if (dccp_parse_options(sk, NULL, skb))
+ return 1;
if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
dccp_event_ack_recv(sk, skb);
- if (dccp_msk(sk)->dccpms_send_ack_vector &&
+ if (dp->dccps_hc_rx_ackvec != NULL &&
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
DCCP_SKB_CB(skb)->dccpd_seq,
DCCP_ACKVEC_STATE_RECEIVED))
goto discard;
- /* XXX see the comments in dccp_rcv_established about this */
- if (dccp_sk(sk)->dccps_role == DCCP_ROLE_CLIENT)
- ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
- else
- ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
+ dccp_deliver_input_to_ccids(sk, skb);
}
/*
* Drop packet and return
*/
if (dh->dccph_type == DCCP_PKT_RESET) {
- /*
- * Queue the equivalent of TCP fin so that dccp_recvmsg
- * exits the loop
- */
- dccp_fin(sk, skb);
- dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
+ dccp_rcv_reset(sk, skb);
return 0;
/*
* Step 7: Check for unexpected packet types
- * If (S.is_server and P.type == CloseReq)
- * or (S.is_server and P.type == Response)
+ * If (S.is_server and P.type == Response)
* or (S.is_client and P.type == Request)
* or (S.state == RESPOND and P.type == Data),
* Send Sync packet acknowledging P.seqno
* Drop packet and return
*/
} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
- (dh->dccph_type == DCCP_PKT_RESPONSE ||
- dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
+ dh->dccph_type == DCCP_PKT_RESPONSE) ||
(dp->dccps_role == DCCP_ROLE_CLIENT &&
dh->dccph_type == DCCP_PKT_REQUEST) ||
(sk->sk_state == DCCP_RESPOND &&
dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
goto discard;
} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
- dccp_rcv_closereq(sk, skb);
+ if (dccp_rcv_closereq(sk, skb))
+ return 0;
goto discard;
} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
- dccp_rcv_close(sk, skb);
- return 0;
- }
-
- if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
- dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
+ if (dccp_rcv_close(sk, skb))
+ return 0;
goto discard;
}
return 1;
case DCCP_REQUESTING:
- /* FIXME: do congestion control initialization */
-
queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
if (queued >= 0)
return queued;
switch (old_state) {
case DCCP_PARTOPEN:
sk->sk_state_change(sk);
- sk_wake_async(sk, 0, POLL_OUT);
+ sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
break;
}
+ } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
+ dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
+ goto discard;
}
if (!queued) {
}
EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
+
+/**
+ * dccp_sample_rtt - Validate and finalise computation of RTT sample
+ * @delta: number of microseconds between packet and acknowledgment
+ * The routine is kept generic to work in different contexts. It should be
+ * called immediately when the ACK used for the RTT sample arrives.
+ */
+u32 dccp_sample_rtt(struct sock *sk, long delta)
+{
+ /* dccpor_elapsed_time is either zeroed out or set and > 0 */
+ delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
+
+ if (unlikely(delta <= 0)) {
+ DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
+ return DCCP_SANE_RTT_MIN;
+ }
+ if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
+ DCCP_WARN("RTT sample %ld too large, using max\n", delta);
+ return DCCP_SANE_RTT_MAX;
+ }
+
+ return delta;
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff