/*
* net/dccp/output.c
- *
+ *
* An implementation of the DCCP protocol
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
dccp_packet_hdr_len(dcb->dccpd_type);
int err, set_ack = 1;
u64 ackno = dp->dccps_gsr;
-
- dccp_inc_seqno(&dp->dccps_gss);
+ /*
+ * Increment GSS here already in case the option code needs it.
+ * Update GSS for real only if option processing below succeeds.
+ */
+ dcb->dccpd_seq = ADD48(dp->dccps_gss, 1);
switch (dcb->dccpd_type) {
case DCCP_PKT_DATA:
set_ack = 0;
/* fall through */
case DCCP_PKT_DATAACK:
+ case DCCP_PKT_RESET:
break;
case DCCP_PKT_REQUEST:
set_ack = 0;
+ /* Use ISS on the first (non-retransmitted) Request. */
+ if (icsk->icsk_retransmits == 0)
+ dcb->dccpd_seq = dp->dccps_iss;
/* fall through */
case DCCP_PKT_SYNC:
case DCCP_PKT_SYNCACK:
- ackno = dcb->dccpd_seq;
+ ackno = dcb->dccpd_ack_seq;
/* fall through */
default:
/*
- * Only data packets should come through with skb->sk
- * set.
+ * Set owner/destructor: some skbs are allocated via
+ * alloc_skb (e.g. when retransmission may happen).
+ * Only Data, DataAck, and Reset packets should come
+ * through here with skb->sk set.
*/
WARN_ON(skb->sk);
skb_set_owner_w(skb, sk);
break;
}
- dcb->dccpd_seq = dp->dccps_gss;
-
if (dccp_insert_options(sk, skb)) {
kfree_skb(skb);
return -EPROTO;
}
-
+
/* Build DCCP header and checksum it. */
dh = dccp_zeroed_hdr(skb, dccp_header_size);
/* XXX For now we're using only 48 bits sequence numbers */
dh->dccph_x = 1;
- dp->dccps_awh = dp->dccps_gss;
+ dccp_update_gss(sk, dcb->dccpd_seq);
dccp_hdr_set_seq(dh, dp->dccps_gss);
if (set_ack)
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
case DCCP_PKT_REQUEST:
dccp_hdr_request(skb)->dccph_req_service =
dp->dccps_service;
+ /*
+ * Limit Ack window to ISS <= P.ackno <= GSS, so that
+ * only Responses to Requests we sent are considered.
+ */
+ dp->dccps_awl = dp->dccps_iss;
break;
case DCCP_PKT_RESET:
dccp_hdr_reset(skb)->dccph_reset_code =
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
- memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
- err = icsk->icsk_af_ops->queue_xmit(skb, sk, 0);
- if (err <= 0)
- return err;
-
- /* NET_XMIT_CN is special. It does not guarantee,
- * that this packet is lost. It tells that device
- * is about to start to drop packets or already
- * drops some packets of the same priority and
- * invokes us to send less aggressively.
- */
- return err == NET_XMIT_CN ? 0 : err;
+ err = icsk->icsk_af_ops->queue_xmit(skb, 0);
+ return net_xmit_eval(err);
}
return -ENOBUFS;
}
+/**
+ * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits
+ * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.),
+ * since the RX CCID is restricted to feedback packets (Acks), which are small
+ * in comparison with the data traffic. A value of 0 means "no current CCMPS".
+ */
+static u32 dccp_determine_ccmps(const struct dccp_sock *dp)
+{
+ const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid;
+
+ if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL)
+ return 0;
+ return tx_ccid->ccid_ops->ccid_ccmps;
+}
+
unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct dccp_sock *dp = dccp_sk(sk);
- int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
- sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
+ u32 ccmps = dccp_determine_ccmps(dp);
+ u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
- /* Now subtract optional transport overhead */
- mss_now -= icsk->icsk_ext_hdr_len;
+ /* Account for header lengths and IPv4/v6 option overhead */
+ cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +
+ sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext));
/*
- * FIXME: this should come from the CCID infrastructure, where, say,
- * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
- * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
- * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
- * make it a multiple of 4
+ * Leave enough headroom for common DCCP header options.
+ * This only considers options which may appear on DCCP-Data packets, as
+ * per table 3 in RFC 4340, 5.8. When running out of space for other
+ * options (eg. Ack Vector which can take up to 255 bytes), it is better
+ * to schedule a separate Ack. Thus we leave headroom for the following:
+ * - 1 byte for Slow Receiver (11.6)
+ * - 6 bytes for Timestamp (13.1)
+ * - 10 bytes for Timestamp Echo (13.3)
+ * - 8 bytes for NDP count (7.7, when activated)
+ * - 6 bytes for Data Checksum (9.3)
+ * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled)
*/
-
- mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
+ cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 +
+ (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4);
/* And store cached results */
icsk->icsk_pmtu_cookie = pmtu;
- dp->dccps_mss_cache = mss_now;
+ dp->dccps_mss_cache = cur_mps;
- return mss_now;
+ return cur_mps;
}
EXPORT_SYMBOL_GPL(dccp_sync_mss);
wake_up_interruptible(sk->sk_sleep);
/* Should agree with poll, otherwise some programs break */
if (sock_writeable(sk))
- sk_wake_async(sk, 2, POLL_OUT);
+ sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
read_unlock(&sk->sk_callback_lock);
}
/**
* dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
- * @sk: socket to wait for
- * @timeo: for how long
+ * @sk: socket to wait for
+ * @skb: current skb to pass on for waiting
+ * @delay: sleep timeout in milliseconds (> 0)
+ * This function is called by default when the socket is closed, and
+ * when a non-zero linger time is set on the socket. For consistency
*/
-static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
- long *timeo)
+static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
{
struct dccp_sock *dp = dccp_sk(sk);
DEFINE_WAIT(wait);
- long delay;
+ unsigned long jiffdelay;
int rc;
- while (1) {
+ do {
+ dccp_pr_debug("delayed send by %d msec\n", delay);
+ jiffdelay = msecs_to_jiffies(delay);
+
prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+ sk->sk_write_pending++;
+ release_sock(sk);
+ schedule_timeout(jiffdelay);
+ lock_sock(sk);
+ sk->sk_write_pending--;
+
if (sk->sk_err)
goto do_error;
- if (!*timeo)
- goto do_nonblock;
if (signal_pending(current))
goto do_interrupted;
- rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
- skb->len);
- if (rc <= 0)
- break;
- delay = msecs_to_jiffies(rc);
- if (delay > *timeo || delay < 0)
- goto do_nonblock;
-
- sk->sk_write_pending++;
- release_sock(sk);
- *timeo -= schedule_timeout(delay);
- lock_sock(sk);
- sk->sk_write_pending--;
- }
+ rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
+ } while ((delay = rc) > 0);
out:
finish_wait(sk->sk_sleep, &wait);
return rc;
do_error:
rc = -EPIPE;
goto out;
-do_nonblock:
- rc = -EAGAIN;
- goto out;
do_interrupted:
- rc = sock_intr_errno(*timeo);
+ rc = -EINTR;
goto out;
}
-static void dccp_write_xmit_timer(unsigned long data) {
- struct sock *sk = (struct sock *)data;
- struct dccp_sock *dp = dccp_sk(sk);
-
- bh_lock_sock(sk);
- if (sock_owned_by_user(sk))
- sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
- else
- dccp_write_xmit(sk, 0);
- bh_unlock_sock(sk);
- sock_put(sk);
-}
-
void dccp_write_xmit(struct sock *sk, int block)
{
struct dccp_sock *dp = dccp_sk(sk);
struct sk_buff *skb;
- long timeo = DCCP_XMIT_TIMEO; /* If a packet is taking longer than
- this we have other issues */
while ((skb = skb_peek(&sk->sk_write_queue))) {
- int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
- skb->len);
+ int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
if (err > 0) {
if (!block) {
sk_reset_timer(sk, &dp->dccps_xmit_timer,
msecs_to_jiffies(err)+jiffies);
break;
- } else {
- err = dccp_wait_for_ccid(sk, skb, &timeo);
- timeo = DCCP_XMIT_TIMEO;
- }
- if (err) {
- printk(KERN_CRIT "%s:err at dccp_wait_for_ccid"
- " %d\n", __FUNCTION__, err);
- dump_stack();
- }
+ } else
+ err = dccp_wait_for_ccid(sk, skb, err);
+ if (err && err != -EINTR)
+ DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
}
skb_dequeue(&sk->sk_write_queue);
const int len = skb->len;
if (sk->sk_state == DCCP_PARTOPEN) {
- /* See 8.1.5. Handshake Completion */
+ const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD;
+ /*
+ * See 8.1.5 - Handshake Completion.
+ *
+ * For robustness we resend Confirm options until the client has
+ * entered OPEN. During the initial feature negotiation, the MPS
+ * is smaller than usual, reduced by the Change/Confirm options.
+ */
+ if (!list_empty(&dp->dccps_featneg) && len > cur_mps) {
+ DCCP_WARN("Payload too large (%d) for featneg.\n", len);
+ dccp_send_ack(sk);
+ dccp_feat_list_purge(&dp->dccps_featneg);
+ }
+
inet_csk_schedule_ack(sk);
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
inet_csk(sk)->icsk_rto,
err = dccp_transmit_skb(sk, skb);
ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
- if (err) {
- printk(KERN_CRIT "%s:err from "
- "ccid_hc_tx_packet_sent %d\n",
- __FUNCTION__, err);
- dump_stack();
- }
- } else
- kfree(skb);
+ if (err)
+ DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
+ err);
+ } else {
+ dccp_pr_debug("packet discarded due to err=%d\n", err);
+ kfree_skb(skb);
+ }
}
}
-int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
+/**
+ * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets
+ * There are only four retransmittable packet types in DCCP:
+ * - Request in client-REQUEST state (sec. 8.1.1),
+ * - CloseReq in server-CLOSEREQ state (sec. 8.3),
+ * - Close in node-CLOSING state (sec. 8.3),
+ * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()).
+ * This function expects sk->sk_send_head to contain the original skb.
+ */
+int dccp_retransmit_skb(struct sock *sk)
{
+ WARN_ON(sk->sk_send_head == NULL);
+
if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
return -EHOSTUNREACH; /* Routing failure or similar. */
- return dccp_transmit_skb(sk, (skb_cloned(skb) ?
- pskb_copy(skb, GFP_ATOMIC):
- skb_clone(skb, GFP_ATOMIC)));
+ /* this count is used to distinguish original and retransmitted skb */
+ inet_csk(sk)->icsk_retransmits++;
+
+ return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
}
struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
/* Reserve space for headers. */
skb_reserve(skb, sk->sk_prot->max_header);
- skb->dst = dst_clone(dst);
+ skb_dst_set(skb, dst_clone(dst));
dreq = dccp_rsk(req);
+ if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
+ dccp_inc_seqno(&dreq->dreq_iss);
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
- if (dccp_insert_options(sk, skb)) {
- kfree_skb(skb);
- return NULL;
- }
+ /* Resolve feature dependencies resulting from choice of CCID */
+ if (dccp_feat_server_ccid_dependencies(dreq))
+ goto response_failed;
+
+ if (dccp_insert_options_rsk(dreq, skb))
+ goto response_failed;
+ /* Build and checksum header */
dh = dccp_zeroed_hdr(skb, dccp_header_size);
- dh->dccph_sport = inet_sk(sk)->sport;
+ dh->dccph_sport = inet_rsk(req)->loc_port;
dh->dccph_dport = inet_rsk(req)->rmt_port;
dh->dccph_doff = (dccp_header_size +
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
dccp_csum_outgoing(skb);
+ /* We use `acked' to remember that a Response was already sent. */
+ inet_rsk(req)->acked = 1;
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
+response_failed:
+ kfree_skb(skb);
+ return NULL;
}
EXPORT_SYMBOL_GPL(dccp_make_response);
-static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
- const enum dccp_reset_codes code)
-
+/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
+struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb)
{
- struct dccp_hdr *dh;
- struct dccp_sock *dp = dccp_sk(sk);
- const u32 dccp_header_size = sizeof(struct dccp_hdr) +
- sizeof(struct dccp_hdr_ext) +
- sizeof(struct dccp_hdr_reset);
- struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
- GFP_ATOMIC);
+ struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
+ struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
+ const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
+ sizeof(struct dccp_hdr_ext) +
+ sizeof(struct dccp_hdr_reset);
+ struct dccp_hdr_reset *dhr;
+ struct sk_buff *skb;
+
+ skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
if (skb == NULL)
return NULL;
- /* Reserve space for headers. */
skb_reserve(skb, sk->sk_prot->max_header);
- skb->dst = dst_clone(dst);
-
- dccp_inc_seqno(&dp->dccps_gss);
-
- DCCP_SKB_CB(skb)->dccpd_reset_code = code;
- DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
- DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
-
- if (dccp_insert_options(sk, skb)) {
- kfree_skb(skb);
- return NULL;
- }
-
- dh = dccp_zeroed_hdr(skb, dccp_header_size);
-
- dh->dccph_sport = inet_sk(sk)->sport;
- dh->dccph_dport = inet_sk(sk)->dport;
- dh->dccph_doff = (dccp_header_size +
- DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
+ /* Swap the send and the receive. */
+ dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
dh->dccph_type = DCCP_PKT_RESET;
+ dh->dccph_sport = rxdh->dccph_dport;
+ dh->dccph_dport = rxdh->dccph_sport;
+ dh->dccph_doff = dccp_hdr_reset_len / 4;
dh->dccph_x = 1;
- dccp_hdr_set_seq(dh, dp->dccps_gss);
- dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
- dccp_hdr_reset(skb)->dccph_reset_code = code;
- inet_csk(sk)->icsk_af_ops->send_check(sk, 0, skb);
+ dhr = dccp_hdr_reset(skb);
+ dhr->dccph_reset_code = dcb->dccpd_reset_code;
+
+ switch (dcb->dccpd_reset_code) {
+ case DCCP_RESET_CODE_PACKET_ERROR:
+ dhr->dccph_reset_data[0] = rxdh->dccph_type;
+ break;
+ case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */
+ case DCCP_RESET_CODE_MANDATORY_ERROR:
+ memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
+ break;
+ }
+ /*
+ * From RFC 4340, 8.3.1:
+ * If P.ackno exists, set R.seqno := P.ackno + 1.
+ * Else set R.seqno := 0.
+ */
+ if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+ dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
+ dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
- DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+ dccp_csum_outgoing(skb);
return skb;
}
+EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
+
+/* send Reset on established socket, to close or abort the connection */
int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
{
+ struct sk_buff *skb;
/*
* FIXME: what if rebuild_header fails?
* Should we be doing a rebuild_header here?
*/
- int err = inet_sk_rebuild_header(sk);
-
- if (err == 0) {
- struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
- code);
- if (skb != NULL) {
- memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
- err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, sk, 0);
- if (err == NET_XMIT_CN)
- err = 0;
- }
- }
+ int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk);
+
+ if (err != 0)
+ return err;
+
+ skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
+ if (skb == NULL)
+ return -ENOBUFS;
- return err;
+ /* Reserve space for headers and prepare control bits. */
+ skb_reserve(skb, sk->sk_prot->max_header);
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
+ DCCP_SKB_CB(skb)->dccpd_reset_code = code;
+
+ return dccp_transmit_skb(sk, skb);
}
/*
sk->sk_err = 0;
sock_reset_flag(sk, SOCK_DONE);
-
+
dccp_sync_mss(sk, dst_mtu(dst));
- dccp_update_gss(sk, dp->dccps_iss);
- /*
- * SWL and AWL are initially adjusted so that they are not less than
- * the initial Sequence Numbers received and sent, respectively:
- * SWL := max(GSR + 1 - floor(W/4), ISR),
- * AWL := max(GSS - W' + 1, ISS).
- * These adjustments MUST be applied only at the beginning of the
- * connection.
- */
- dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
+ /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
+ dp->dccps_gar = dp->dccps_iss;
icsk->icsk_retransmits = 0;
- init_timer(&dp->dccps_xmit_timer);
- dp->dccps_xmit_timer.data = (unsigned long)sk;
- dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
}
int dccp_connect(struct sock *sk)
struct sk_buff *skb;
struct inet_connection_sock *icsk = inet_csk(sk);
+ /* do not connect if feature negotiation setup fails */
+ if (dccp_feat_finalise_settings(dccp_sk(sk)))
+ return -EPROTO;
+
dccp_connect_init(sk);
skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
EXPORT_SYMBOL_GPL(dccp_send_ack);
+#if 0
+/* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
void dccp_send_delayed_ack(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
icsk->icsk_ack.timeout = timeout;
sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
}
+#endif
-void dccp_send_sync(struct sock *sk, const u64 seq,
+void dccp_send_sync(struct sock *sk, const u64 ackno,
const enum dccp_pkt_type pkt_type)
{
/*
*/
struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
- if (skb == NULL)
+ if (skb == NULL) {
/* FIXME: how to make sure the sync is sent? */
+ DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type));
return;
+ }
/* Reserve space for headers and prepare control bits. */
skb_reserve(skb, sk->sk_prot->max_header);
DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
- DCCP_SKB_CB(skb)->dccpd_seq = seq;
+ DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;
dccp_transmit_skb(sk, skb);
}
/* Reserve space for headers and prepare control bits. */
skb_reserve(skb, sk->sk_prot->max_header);
- DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
- DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
+ if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait)
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ;
+ else
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE;
if (active) {
dccp_write_xmit(sk, 1);
dccp_skb_entail(sk, skb);
dccp_transmit_skb(sk, skb_clone(skb, prio));
- /* FIXME do we need a retransmit timer here? */
+ /*
+ * Retransmission timer for active-close: RFC 4340, 8.3 requires
+ * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ
+ * state can be left. The initial timeout is 2 RTTs.
+ * Since RTT measurement is done by the CCIDs, there is no easy
+ * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4
+ * is too low (200ms); we use a high value to avoid unnecessary
+ * retransmissions when the link RTT is > 0.2 seconds.
+ * FIXME: Let main module sample RTTs and use that instead.
+ */
+ inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+ DCCP_TIMEOUT_INIT, DCCP_RTO_MAX);
} else
dccp_transmit_skb(sk, skb);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff