tcp_timer.c: Add kernel-doc function descriptions
This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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Richard Sailer
David S. Miller
parent
7dc0993452
commit
c380d37e97
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@ -24,6 +24,13 @@
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int sysctl_tcp_thin_linear_timeouts __read_mostly;
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/**
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* tcp_write_err() - close socket and save error info
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* @sk: The socket the error has appeared on.
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*
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* Returns: Nothing (void)
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*/
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static void tcp_write_err(struct sock *sk)
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{
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sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
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@ -33,16 +40,21 @@ static void tcp_write_err(struct sock *sk)
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__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONTIMEOUT);
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}
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/* Do not allow orphaned sockets to eat all our resources.
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* This is direct violation of TCP specs, but it is required
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* to prevent DoS attacks. It is called when a retransmission timeout
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* or zero probe timeout occurs on orphaned socket.
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/**
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* tcp_out_of_resources() - Close socket if out of resources
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* @sk: pointer to current socket
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* @do_reset: send a last packet with reset flag
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*
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* Criteria is still not confirmed experimentally and may change.
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* We kill the socket, if:
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* 1. If number of orphaned sockets exceeds an administratively configured
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* limit.
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* 2. If we have strong memory pressure.
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* Do not allow orphaned sockets to eat all our resources.
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* This is direct violation of TCP specs, but it is required
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* to prevent DoS attacks. It is called when a retransmission timeout
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* or zero probe timeout occurs on orphaned socket.
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*
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* Criteria is still not confirmed experimentally and may change.
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* We kill the socket, if:
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* 1. If number of orphaned sockets exceeds an administratively configured
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* limit.
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* 2. If we have strong memory pressure.
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*/
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static int tcp_out_of_resources(struct sock *sk, bool do_reset)
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{
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@ -74,7 +86,11 @@ static int tcp_out_of_resources(struct sock *sk, bool do_reset)
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return 0;
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}
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/* Calculate maximal number or retries on an orphaned socket. */
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/**
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* tcp_orphan_retries() - Returns maximal number of retries on an orphaned socket
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* @sk: Pointer to the current socket.
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* @alive: bool, socket alive state
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*/
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static int tcp_orphan_retries(struct sock *sk, bool alive)
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{
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int retries = sock_net(sk)->ipv4.sysctl_tcp_orphan_retries; /* May be zero. */
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@ -115,10 +131,22 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
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}
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}
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/* This function calculates a "timeout" which is equivalent to the timeout of a
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* TCP connection after "boundary" unsuccessful, exponentially backed-off
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/**
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* retransmits_timed_out() - returns true if this connection has timed out
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* @sk: The current socket
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* @boundary: max number of retransmissions
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* @timeout: A custom timeout value.
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* If set to 0 the default timeout is calculated and used.
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* Using TCP_RTO_MIN and the number of unsuccessful retransmits.
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* @syn_set: true if the SYN Bit was set.
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*
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* The default "timeout" value this function can calculate and use
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* is equivalent to the timeout of a TCP Connection
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* after "boundary" unsuccessful, exponentially backed-off
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* retransmissions with an initial RTO of TCP_RTO_MIN or TCP_TIMEOUT_INIT if
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* syn_set flag is set.
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*
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*/
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static bool retransmits_timed_out(struct sock *sk,
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unsigned int boundary,
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@ -257,6 +285,16 @@ out:
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sk_mem_reclaim(sk);
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}
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/**
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* tcp_delack_timer() - The TCP delayed ACK timeout handler
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* @data: Pointer to the current socket. (gets casted to struct sock *)
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*
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* This function gets (indirectly) called when the kernel timer for a TCP packet
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* of this socket expires. Calls tcp_delack_timer_handler() to do the actual work.
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*
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* Returns: Nothing (void)
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*/
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static void tcp_delack_timer(unsigned long data)
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{
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struct sock *sk = (struct sock *)data;
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@ -350,10 +388,18 @@ static void tcp_fastopen_synack_timer(struct sock *sk)
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TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
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}
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/*
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* The TCP retransmit timer.
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*/
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/**
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* tcp_retransmit_timer() - The TCP retransmit timeout handler
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* @sk: Pointer to the current socket.
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*
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* This function gets called when the kernel timer for a TCP packet
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* of this socket expires.
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*
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* It handles retransmission, timer adjustment and other necesarry measures.
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*
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* Returns: Nothing (void)
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*/
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void tcp_retransmit_timer(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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@ -494,7 +540,8 @@ out_reset_timer:
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out:;
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}
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/* Called with BH disabled */
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/* Called with bottom-half processing disabled.
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Called by tcp_write_timer() */
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void tcp_write_timer_handler(struct sock *sk)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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@ -539,7 +586,7 @@ static void tcp_write_timer(unsigned long data)
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if (!sock_owned_by_user(sk)) {
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tcp_write_timer_handler(sk);
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} else {
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/* deleguate our work to tcp_release_cb() */
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/* delegate our work to tcp_release_cb() */
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if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags))
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sock_hold(sk);
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}
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