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-rw-r--r--net/dccp/timer.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/net/dccp/timer.c b/net/dccp/timer.c
new file mode 100644
index 000000000..a934d2932
--- /dev/null
+++ b/net/dccp/timer.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/dccp/timer.c
+ *
+ * An implementation of the DCCP protocol
+ * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ */
+
+#include <linux/dccp.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+
+#include "dccp.h"
+
+/* sysctl variables governing numbers of retransmission attempts */
+int sysctl_dccp_request_retries __read_mostly = TCP_SYN_RETRIES;
+int sysctl_dccp_retries1 __read_mostly = TCP_RETR1;
+int sysctl_dccp_retries2 __read_mostly = TCP_RETR2;
+
+static void dccp_write_err(struct sock *sk)
+{
+ sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
+ sk->sk_error_report(sk);
+
+ dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
+ dccp_done(sk);
+ __DCCP_INC_STATS(DCCP_MIB_ABORTONTIMEOUT);
+}
+
+/* A write timeout has occurred. Process the after effects. */
+static int dccp_write_timeout(struct sock *sk)
+{
+ const struct inet_connection_sock *icsk = inet_csk(sk);
+ int retry_until;
+
+ if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
+ if (icsk->icsk_retransmits != 0)
+ dst_negative_advice(sk);
+ retry_until = icsk->icsk_syn_retries ?
+ : sysctl_dccp_request_retries;
+ } else {
+ if (icsk->icsk_retransmits >= sysctl_dccp_retries1) {
+ /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
+ black hole detection. :-(
+
+ It is place to make it. It is not made. I do not want
+ to make it. It is disguisting. It does not work in any
+ case. Let me to cite the same draft, which requires for
+ us to implement this:
+
+ "The one security concern raised by this memo is that ICMP black holes
+ are often caused by over-zealous security administrators who block
+ all ICMP messages. It is vitally important that those who design and
+ deploy security systems understand the impact of strict filtering on
+ upper-layer protocols. The safest web site in the world is worthless
+ if most TCP implementations cannot transfer data from it. It would
+ be far nicer to have all of the black holes fixed rather than fixing
+ all of the TCP implementations."
+
+ Golden words :-).
+ */
+
+ dst_negative_advice(sk);
+ }
+
+ retry_until = sysctl_dccp_retries2;
+ /*
+ * FIXME: see tcp_write_timout and tcp_out_of_resources
+ */
+ }
+
+ if (icsk->icsk_retransmits >= retry_until) {
+ /* Has it gone just too far? */
+ dccp_write_err(sk);
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * The DCCP retransmit timer.
+ */
+static void dccp_retransmit_timer(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ /*
+ * More than 4MSL (8 minutes) has passed, a RESET(aborted) was
+ * sent, no need to retransmit, this sock is dead.
+ */
+ if (dccp_write_timeout(sk))
+ return;
+
+ /*
+ * We want to know the number of packets retransmitted, not the
+ * total number of retransmissions of clones of original packets.
+ */
+ if (icsk->icsk_retransmits == 0)
+ __DCCP_INC_STATS(DCCP_MIB_TIMEOUTS);
+
+ if (dccp_retransmit_skb(sk) != 0) {
+ /*
+ * Retransmission failed because of local congestion,
+ * do not backoff.
+ */
+ if (--icsk->icsk_retransmits == 0)
+ icsk->icsk_retransmits = 1;
+ inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+ min(icsk->icsk_rto,
+ TCP_RESOURCE_PROBE_INTERVAL),
+ DCCP_RTO_MAX);
+ return;
+ }
+
+ icsk->icsk_backoff++;
+
+ icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
+ inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
+ DCCP_RTO_MAX);
+ if (icsk->icsk_retransmits > sysctl_dccp_retries1)
+ __sk_dst_reset(sk);
+}
+
+static void dccp_write_timer(struct timer_list *t)
+{
+ struct inet_connection_sock *icsk =
+ from_timer(icsk, t, icsk_retransmit_timer);
+ struct sock *sk = &icsk->icsk_inet.sk;
+ int event = 0;
+
+ bh_lock_sock(sk);
+ if (sock_owned_by_user(sk)) {
+ /* Try again later */
+ sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
+ jiffies + (HZ / 20));
+ goto out;
+ }
+
+ if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
+ goto out;
+
+ if (time_after(icsk->icsk_timeout, jiffies)) {
+ sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
+ icsk->icsk_timeout);
+ goto out;
+ }
+
+ event = icsk->icsk_pending;
+ icsk->icsk_pending = 0;
+
+ switch (event) {
+ case ICSK_TIME_RETRANS:
+ dccp_retransmit_timer(sk);
+ break;
+ }
+out:
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+static void dccp_keepalive_timer(struct timer_list *t)
+{
+ struct sock *sk = from_timer(sk, t, sk_timer);
+
+ pr_err("dccp should not use a keepalive timer !\n");
+ sock_put(sk);
+}
+
+/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
+static void dccp_delack_timer(struct timer_list *t)
+{
+ struct inet_connection_sock *icsk =
+ from_timer(icsk, t, icsk_delack_timer);
+ struct sock *sk = &icsk->icsk_inet.sk;
+
+ bh_lock_sock(sk);
+ if (sock_owned_by_user(sk)) {
+ /* Try again later. */
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
+ sk_reset_timer(sk, &icsk->icsk_delack_timer,
+ jiffies + TCP_DELACK_MIN);
+ goto out;
+ }
+
+ if (sk->sk_state == DCCP_CLOSED ||
+ !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
+ goto out;
+ if (time_after(icsk->icsk_ack.timeout, jiffies)) {
+ sk_reset_timer(sk, &icsk->icsk_delack_timer,
+ icsk->icsk_ack.timeout);
+ goto out;
+ }
+
+ icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
+
+ if (inet_csk_ack_scheduled(sk)) {
+ if (!inet_csk_in_pingpong_mode(sk)) {
+ /* Delayed ACK missed: inflate ATO. */
+ icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
+ icsk->icsk_rto);
+ } else {
+ /* Delayed ACK missed: leave pingpong mode and
+ * deflate ATO.
+ */
+ inet_csk_exit_pingpong_mode(sk);
+ icsk->icsk_ack.ato = TCP_ATO_MIN;
+ }
+ dccp_send_ack(sk);
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKS);
+ }
+out:
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+/**
+ * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface
+ * @data: Socket to act on
+ *
+ * See the comments above %ccid_dequeueing_decision for supported modes.
+ */
+static void dccp_write_xmitlet(unsigned long data)
+{
+ struct sock *sk = (struct sock *)data;
+
+ bh_lock_sock(sk);
+ if (sock_owned_by_user(sk))
+ sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1);
+ else
+ dccp_write_xmit(sk);
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+static void dccp_write_xmit_timer(struct timer_list *t)
+{
+ struct dccp_sock *dp = from_timer(dp, t, dccps_xmit_timer);
+ struct sock *sk = &dp->dccps_inet_connection.icsk_inet.sk;
+
+ dccp_write_xmitlet((unsigned long)sk);
+}
+
+void dccp_init_xmit_timers(struct sock *sk)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+
+ tasklet_init(&dp->dccps_xmitlet, dccp_write_xmitlet, (unsigned long)sk);
+ timer_setup(&dp->dccps_xmit_timer, dccp_write_xmit_timer, 0);
+ inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
+ &dccp_keepalive_timer);
+}
+
+static ktime_t dccp_timestamp_seed;
+/**
+ * dccp_timestamp - 10s of microseconds time source
+ * Returns the number of 10s of microseconds since loading DCCP. This is native
+ * DCCP time difference format (RFC 4340, sec. 13).
+ * Please note: This will wrap around about circa every 11.9 hours.
+ */
+u32 dccp_timestamp(void)
+{
+ u64 delta = (u64)ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
+
+ do_div(delta, 10);
+ return delta;
+}
+EXPORT_SYMBOL_GPL(dccp_timestamp);
+
+void __init dccp_timestamping_init(void)
+{
+ dccp_timestamp_seed = ktime_get_real();
+}
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