diff options
Diffstat (limited to 'kernel/net/dccp/timer.c')
| -rw-r--r-- | kernel/net/dccp/timer.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/kernel/net/dccp/timer.c b/kernel/net/dccp/timer.c new file mode 100644 index 000000000..3ef7acef3 --- /dev/null +++ b/kernel/net/dccp/timer.c @@ -0,0 +1,271 @@ +/* + * net/dccp/timer.c + * + * An implementation of the DCCP protocol + * Arnaldo Carvalho de Melo <acme@conectiva.com.br> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#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_BH(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 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_BH(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(unsigned long data) +{ + struct sock *sk = (struct sock *)data; + struct inet_connection_sock *icsk = inet_csk(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(unsigned long data) +{ + struct sock *sk = (struct sock *)data; + + 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(unsigned long data) +{ + struct sock *sk = (struct sock *)data; + struct inet_connection_sock *icsk = inet_csk(sk); + + bh_lock_sock(sk); + if (sock_owned_by_user(sk)) { + /* Try again later. */ + icsk->icsk_ack.blocked = 1; + NET_INC_STATS_BH(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 (!icsk->icsk_ack.pingpong) { + /* 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. + */ + icsk->icsk_ack.pingpong = 0; + icsk->icsk_ack.ato = TCP_ATO_MIN; + } + dccp_send_ack(sk); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS); + } +out: + bh_unlock_sock(sk); + sock_put(sk); +} + +/** + * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface + * 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); +} + +static void dccp_write_xmit_timer(unsigned long data) +{ + dccp_write_xmitlet(data); + sock_put((struct sock *)data); +} + +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); + setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer, + (unsigned long)sk); + 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(); +} |