![Gerrit Renker](/assets/img/avatar_default.png)
This patch fixes the following sparse warnings: * nested min(max()) expression: net/dccp/ccids/ccid3.c:91:21: warning: symbol '__x' shadows an earlier one net/dccp/ccids/ccid3.c:91:21: warning: symbol '__y' shadows an earlier one * Declaration of function prototypes in .c instead of .h file, resulting in "should it be static?" warnings. * Declared "struct dccpw" static (local to dccp_probe). * Disabled dccp_delayed_ack() - not fully removed due to RFC 4340, 11.3 ("Receivers SHOULD implement delayed acknowledgement timers ..."). * Used a different local variable name to avoid net/dccp/ackvec.c:293:13: warning: symbol 'state' shadows an earlier one net/dccp/ackvec.c:238:33: originally declared here * Removed unused functions `dccp_ackvector_print' and `dccp_ackvec_print'. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
611 lines
17 KiB
C
611 lines
17 KiB
C
/*
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* net/dccp/output.c
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*
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* An implementation of the DCCP protocol
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/dccp.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <net/inet_sock.h>
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#include <net/sock.h>
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#include "ackvec.h"
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#include "ccid.h"
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#include "dccp.h"
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static inline void dccp_event_ack_sent(struct sock *sk)
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{
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inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
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}
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static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
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{
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skb_set_owner_w(skb, sk);
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WARN_ON(sk->sk_send_head);
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sk->sk_send_head = skb;
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}
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/*
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* All SKB's seen here are completely headerless. It is our
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* job to build the DCCP header, and pass the packet down to
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* IP so it can do the same plus pass the packet off to the
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* device.
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*/
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static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
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{
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if (likely(skb != NULL)) {
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const struct inet_sock *inet = inet_sk(sk);
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const struct inet_connection_sock *icsk = inet_csk(sk);
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struct dccp_sock *dp = dccp_sk(sk);
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struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
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struct dccp_hdr *dh;
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/* XXX For now we're using only 48 bits sequence numbers */
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const u32 dccp_header_size = sizeof(*dh) +
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sizeof(struct dccp_hdr_ext) +
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dccp_packet_hdr_len(dcb->dccpd_type);
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int err, set_ack = 1;
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u64 ackno = dp->dccps_gsr;
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dccp_inc_seqno(&dp->dccps_gss);
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switch (dcb->dccpd_type) {
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case DCCP_PKT_DATA:
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set_ack = 0;
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/* fall through */
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case DCCP_PKT_DATAACK:
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case DCCP_PKT_RESET:
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break;
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case DCCP_PKT_REQUEST:
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set_ack = 0;
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/* fall through */
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case DCCP_PKT_SYNC:
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case DCCP_PKT_SYNCACK:
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ackno = dcb->dccpd_ack_seq;
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/* fall through */
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default:
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/*
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* Set owner/destructor: some skbs are allocated via
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* alloc_skb (e.g. when retransmission may happen).
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* Only Data, DataAck, and Reset packets should come
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* through here with skb->sk set.
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*/
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WARN_ON(skb->sk);
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skb_set_owner_w(skb, sk);
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break;
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}
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dcb->dccpd_seq = dp->dccps_gss;
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if (dccp_insert_options(sk, skb)) {
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kfree_skb(skb);
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return -EPROTO;
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}
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/* Build DCCP header and checksum it. */
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dh = dccp_zeroed_hdr(skb, dccp_header_size);
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dh->dccph_type = dcb->dccpd_type;
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dh->dccph_sport = inet->sport;
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dh->dccph_dport = inet->dport;
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dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
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dh->dccph_ccval = dcb->dccpd_ccval;
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dh->dccph_cscov = dp->dccps_pcslen;
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/* XXX For now we're using only 48 bits sequence numbers */
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dh->dccph_x = 1;
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dp->dccps_awh = dp->dccps_gss;
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dccp_hdr_set_seq(dh, dp->dccps_gss);
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if (set_ack)
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dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
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switch (dcb->dccpd_type) {
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case DCCP_PKT_REQUEST:
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dccp_hdr_request(skb)->dccph_req_service =
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dp->dccps_service;
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break;
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case DCCP_PKT_RESET:
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dccp_hdr_reset(skb)->dccph_reset_code =
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dcb->dccpd_reset_code;
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break;
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}
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icsk->icsk_af_ops->send_check(sk, 0, skb);
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if (set_ack)
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dccp_event_ack_sent(sk);
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DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
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err = icsk->icsk_af_ops->queue_xmit(skb, 0);
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return net_xmit_eval(err);
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}
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return -ENOBUFS;
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}
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/**
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* dccp_determine_ccmps - Find out about CCID-specfic packet-size limits
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* We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.),
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* since the RX CCID is restricted to feedback packets (Acks), which are small
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* in comparison with the data traffic. A value of 0 means "no current CCMPS".
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*/
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static u32 dccp_determine_ccmps(const struct dccp_sock *dp)
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{
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const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid;
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if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL)
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return 0;
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return tx_ccid->ccid_ops->ccid_ccmps;
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}
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unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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struct dccp_sock *dp = dccp_sk(sk);
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u32 ccmps = dccp_determine_ccmps(dp);
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int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
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/* Account for header lengths and IPv4/v6 option overhead */
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cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +
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sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext));
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/*
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* FIXME: this should come from the CCID infrastructure, where, say,
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* TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
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* put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
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* TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
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* make it a multiple of 4
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*/
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cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
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/* And store cached results */
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icsk->icsk_pmtu_cookie = pmtu;
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dp->dccps_mss_cache = cur_mps;
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return cur_mps;
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}
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EXPORT_SYMBOL_GPL(dccp_sync_mss);
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void dccp_write_space(struct sock *sk)
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{
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read_lock(&sk->sk_callback_lock);
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if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
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wake_up_interruptible(sk->sk_sleep);
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/* Should agree with poll, otherwise some programs break */
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if (sock_writeable(sk))
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sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
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read_unlock(&sk->sk_callback_lock);
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}
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/**
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* dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
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* @sk: socket to wait for
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* @skb: current skb to pass on for waiting
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* @delay: sleep timeout in milliseconds (> 0)
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* This function is called by default when the socket is closed, and
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* when a non-zero linger time is set on the socket. For consistency
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*/
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static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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DEFINE_WAIT(wait);
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unsigned long jiffdelay;
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int rc;
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do {
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dccp_pr_debug("delayed send by %d msec\n", delay);
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jiffdelay = msecs_to_jiffies(delay);
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prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
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sk->sk_write_pending++;
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release_sock(sk);
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schedule_timeout(jiffdelay);
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lock_sock(sk);
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sk->sk_write_pending--;
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if (sk->sk_err)
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goto do_error;
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if (signal_pending(current))
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goto do_interrupted;
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rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
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} while ((delay = rc) > 0);
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out:
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finish_wait(sk->sk_sleep, &wait);
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return rc;
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do_error:
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rc = -EPIPE;
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goto out;
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do_interrupted:
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rc = -EINTR;
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goto out;
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}
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void dccp_write_xmit(struct sock *sk, int block)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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struct sk_buff *skb;
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while ((skb = skb_peek(&sk->sk_write_queue))) {
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int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
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if (err > 0) {
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if (!block) {
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sk_reset_timer(sk, &dp->dccps_xmit_timer,
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msecs_to_jiffies(err)+jiffies);
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break;
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} else
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err = dccp_wait_for_ccid(sk, skb, err);
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if (err && err != -EINTR)
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DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
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}
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skb_dequeue(&sk->sk_write_queue);
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if (err == 0) {
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struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
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const int len = skb->len;
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if (sk->sk_state == DCCP_PARTOPEN) {
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/* See 8.1.5. Handshake Completion */
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inet_csk_schedule_ack(sk);
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inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
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inet_csk(sk)->icsk_rto,
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DCCP_RTO_MAX);
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dcb->dccpd_type = DCCP_PKT_DATAACK;
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} else if (dccp_ack_pending(sk))
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dcb->dccpd_type = DCCP_PKT_DATAACK;
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else
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dcb->dccpd_type = DCCP_PKT_DATA;
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err = dccp_transmit_skb(sk, skb);
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ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
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if (err)
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DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
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err);
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} else {
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dccp_pr_debug("packet discarded due to err=%d\n", err);
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kfree_skb(skb);
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}
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}
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}
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int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
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{
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if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
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return -EHOSTUNREACH; /* Routing failure or similar. */
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return dccp_transmit_skb(sk, (skb_cloned(skb) ?
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pskb_copy(skb, GFP_ATOMIC):
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skb_clone(skb, GFP_ATOMIC)));
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}
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struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
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struct request_sock *req)
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{
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struct dccp_hdr *dh;
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struct dccp_request_sock *dreq;
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const u32 dccp_header_size = sizeof(struct dccp_hdr) +
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sizeof(struct dccp_hdr_ext) +
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sizeof(struct dccp_hdr_response);
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struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
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GFP_ATOMIC);
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if (skb == NULL)
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return NULL;
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/* Reserve space for headers. */
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skb_reserve(skb, sk->sk_prot->max_header);
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skb->dst = dst_clone(dst);
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dreq = dccp_rsk(req);
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if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
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dccp_inc_seqno(&dreq->dreq_iss);
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DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
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DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
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if (dccp_insert_options_rsk(dreq, skb)) {
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kfree_skb(skb);
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return NULL;
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}
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/* Build and checksum header */
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dh = dccp_zeroed_hdr(skb, dccp_header_size);
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dh->dccph_sport = inet_sk(sk)->sport;
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dh->dccph_dport = inet_rsk(req)->rmt_port;
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dh->dccph_doff = (dccp_header_size +
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DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
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dh->dccph_type = DCCP_PKT_RESPONSE;
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dh->dccph_x = 1;
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dccp_hdr_set_seq(dh, dreq->dreq_iss);
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dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
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dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
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dccp_csum_outgoing(skb);
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/* We use `acked' to remember that a Response was already sent. */
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inet_rsk(req)->acked = 1;
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DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
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return skb;
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}
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EXPORT_SYMBOL_GPL(dccp_make_response);
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/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
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struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb)
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{
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struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
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struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
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const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
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sizeof(struct dccp_hdr_ext) +
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sizeof(struct dccp_hdr_reset);
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struct dccp_hdr_reset *dhr;
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struct sk_buff *skb;
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skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
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if (skb == NULL)
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return NULL;
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skb_reserve(skb, sk->sk_prot->max_header);
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/* Swap the send and the receive. */
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dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
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dh->dccph_type = DCCP_PKT_RESET;
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dh->dccph_sport = rxdh->dccph_dport;
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dh->dccph_dport = rxdh->dccph_sport;
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dh->dccph_doff = dccp_hdr_reset_len / 4;
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dh->dccph_x = 1;
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dhr = dccp_hdr_reset(skb);
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dhr->dccph_reset_code = dcb->dccpd_reset_code;
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switch (dcb->dccpd_reset_code) {
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case DCCP_RESET_CODE_PACKET_ERROR:
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dhr->dccph_reset_data[0] = rxdh->dccph_type;
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break;
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case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */
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case DCCP_RESET_CODE_MANDATORY_ERROR:
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memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
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break;
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}
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/*
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* From RFC 4340, 8.3.1:
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* If P.ackno exists, set R.seqno := P.ackno + 1.
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* Else set R.seqno := 0.
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*/
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if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
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dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
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dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
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dccp_csum_outgoing(skb);
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return skb;
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}
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EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
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/* send Reset on established socket, to close or abort the connection */
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int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
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{
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struct sk_buff *skb;
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/*
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* FIXME: what if rebuild_header fails?
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* Should we be doing a rebuild_header here?
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*/
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int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk);
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if (err != 0)
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return err;
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skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
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if (skb == NULL)
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return -ENOBUFS;
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/* Reserve space for headers and prepare control bits. */
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skb_reserve(skb, sk->sk_prot->max_header);
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DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
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DCCP_SKB_CB(skb)->dccpd_reset_code = code;
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return dccp_transmit_skb(sk, skb);
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}
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/*
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* Do all connect socket setups that can be done AF independent.
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*/
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static inline void dccp_connect_init(struct sock *sk)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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struct dst_entry *dst = __sk_dst_get(sk);
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struct inet_connection_sock *icsk = inet_csk(sk);
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sk->sk_err = 0;
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sock_reset_flag(sk, SOCK_DONE);
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dccp_sync_mss(sk, dst_mtu(dst));
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/*
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* SWL and AWL are initially adjusted so that they are not less than
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* 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_update_gss(sk, dp->dccps_iss);
|
|
dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
|
|
|
|
/* S.GAR - greatest valid acknowledgement number received on a non-Sync;
|
|
* initialized to S.ISS (sec. 8.5) */
|
|
dp->dccps_gar = dp->dccps_iss;
|
|
|
|
icsk->icsk_retransmits = 0;
|
|
}
|
|
|
|
int dccp_connect(struct sock *sk)
|
|
{
|
|
struct sk_buff *skb;
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
|
|
|
dccp_connect_init(sk);
|
|
|
|
skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
|
|
if (unlikely(skb == NULL))
|
|
return -ENOBUFS;
|
|
|
|
/* Reserve space for headers. */
|
|
skb_reserve(skb, sk->sk_prot->max_header);
|
|
|
|
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
|
|
|
|
dccp_skb_entail(sk, skb);
|
|
dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
|
|
DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
|
|
|
|
/* Timer for repeating the REQUEST until an answer. */
|
|
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
|
|
icsk->icsk_rto, DCCP_RTO_MAX);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(dccp_connect);
|
|
|
|
void dccp_send_ack(struct sock *sk)
|
|
{
|
|
/* If we have been reset, we may not send again. */
|
|
if (sk->sk_state != DCCP_CLOSED) {
|
|
struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
|
|
GFP_ATOMIC);
|
|
|
|
if (skb == NULL) {
|
|
inet_csk_schedule_ack(sk);
|
|
inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
|
|
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
|
|
TCP_DELACK_MAX,
|
|
DCCP_RTO_MAX);
|
|
return;
|
|
}
|
|
|
|
/* Reserve space for headers */
|
|
skb_reserve(skb, sk->sk_prot->max_header);
|
|
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
|
|
dccp_transmit_skb(sk, skb);
|
|
}
|
|
}
|
|
|
|
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);
|
|
/*
|
|
* FIXME: tune this timer. elapsed time fixes the skew, so no problem
|
|
* with using 2s, and active senders also piggyback the ACK into a
|
|
* DATAACK packet, so this is really for quiescent senders.
|
|
*/
|
|
unsigned long timeout = jiffies + 2 * HZ;
|
|
|
|
/* Use new timeout only if there wasn't a older one earlier. */
|
|
if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
|
|
/* If delack timer was blocked or is about to expire,
|
|
* send ACK now.
|
|
*
|
|
* FIXME: check the "about to expire" part
|
|
*/
|
|
if (icsk->icsk_ack.blocked) {
|
|
dccp_send_ack(sk);
|
|
return;
|
|
}
|
|
|
|
if (!time_before(timeout, icsk->icsk_ack.timeout))
|
|
timeout = icsk->icsk_ack.timeout;
|
|
}
|
|
icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
|
|
icsk->icsk_ack.timeout = timeout;
|
|
sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
|
|
}
|
|
#endif
|
|
|
|
void dccp_send_sync(struct sock *sk, const u64 ackno,
|
|
const enum dccp_pkt_type pkt_type)
|
|
{
|
|
/*
|
|
* We are not putting this on the write queue, so
|
|
* dccp_transmit_skb() will set the ownership to this
|
|
* sock.
|
|
*/
|
|
struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
|
|
|
|
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_ack_seq = ackno;
|
|
|
|
dccp_transmit_skb(sk, skb);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(dccp_send_sync);
|
|
|
|
/*
|
|
* Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
|
|
* cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
|
|
* any circumstances.
|
|
*/
|
|
void dccp_send_close(struct sock *sk, const int active)
|
|
{
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
|
struct sk_buff *skb;
|
|
const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
|
|
|
|
skb = alloc_skb(sk->sk_prot->max_header, prio);
|
|
if (skb == NULL)
|
|
return;
|
|
|
|
/* Reserve space for headers and prepare control bits. */
|
|
skb_reserve(skb, sk->sk_prot->max_header);
|
|
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));
|
|
/*
|
|
* 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);
|
|
}
|