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![Andrew Lunn](/assets/img/avatar_default.png)
net/dccp/ccids/ccid2.c:190: warning: Function parameter or member 'hc' not described in 'ccid2_update_used_window' net/dccp/ccids/ccid2.c:190: warning: Function parameter or member 'new_wnd' not described in 'ccid2_update_used_window' net/dccp/ccids/ccid2.c:360: warning: Function parameter or member 'sk' not described in 'ccid2_rtt_estimator' net/dccp/ccids/ccid3.c:112: warning: Function parameter or member 'sk' not described in 'ccid3_hc_tx_update_x' net/dccp/ccids/ccid3.c:159: warning: Function parameter or member 'hc' not described in 'ccid3_hc_tx_update_s' net/dccp/ccids/ccid3.c:268: warning: Function parameter or member 'sk' not described in 'ccid3_hc_tx_send_packet' net/dccp/ccids/ccid3.c:667: warning: Function parameter or member 'sk' not described in 'ccid3_first_li' net/dccp/ccids/ccid3.c:85: warning: Function parameter or member 'hc' not described in 'ccid3_update_send_interval' net/dccp/ccids/lib/loss_interval.c:85: warning: Function parameter or member 'lh' not described in 'tfrc_lh_update_i_mean' net/dccp/ccids/lib/loss_interval.c:85: warning: Function parameter or member 'skb' not described in 'tfrc_lh_update_i_mean' net/dccp/ccids/lib/packet_history.c:392: warning: Function parameter or member 'h' not described in 'tfrc_rx_hist_sample_rtt' net/dccp/ccids/lib/packet_history.c:392: warning: Function parameter or member 'skb' not described in 'tfrc_rx_hist_sample_rtt' net/dccp/feat.c:1003: warning: Function parameter or member 'dreq' not described in 'dccp_feat_server_ccid_dependencies' net/dccp/feat.c:1040: warning: Function parameter or member 'array_len' not described in 'dccp_feat_prefer' net/dccp/feat.c:1040: warning: Function parameter or member 'array' not described in 'dccp_feat_prefer' net/dccp/feat.c:1040: warning: Function parameter or member 'preferred_value' not described in 'dccp_feat_prefer' net/dccp/output.c:151: warning: Function parameter or member 'dp' not described in 'dccp_determine_ccmps' net/dccp/output.c:242: warning: Function parameter or member 'sk' not described in 'dccp_xmit_packet' net/dccp/output.c:305: warning: Function parameter or member 'sk' not described in 'dccp_flush_write_queue' net/dccp/output.c:305: warning: Function parameter or member 'time_budget' not described in 'dccp_flush_write_queue' net/dccp/output.c:378: warning: Function parameter or member 'sk' not described in 'dccp_retransmit_skb' net/dccp/qpolicy.c:88: warning: Function parameter or member '' not described in 'dccp_qpolicy_operations' net/dccp/qpolicy.c:88: warning: Function parameter or member '{' not described in 'dccp_qpolicy_operations' net/dccp/qpolicy.c:88: warning: Function parameter or member 'params' not described in 'dccp_qpolicy_operations' Signed-off-by: Andrew Lunn <andrew@lunn.ch> Link: https://lore.kernel.org/r/20201028011412.931250-1-andrew@lunn.ch Signed-off-by: Jakub Kicinski <kuba@kernel.org>
709 lines
20 KiB
C
709 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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#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 <linux/slab.h>
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#include <linux/sched/signal.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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/* enqueue @skb on sk_send_head for retransmission, return clone to send now */
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static struct sk_buff *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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return skb_clone(sk->sk_send_head, gfp_any());
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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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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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/*
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* Increment GSS here already in case the option code needs it.
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* Update GSS for real only if option processing below succeeds.
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*/
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dcb->dccpd_seq = ADD48(dp->dccps_gss, 1);
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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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fallthrough;
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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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/* Use ISS on the first (non-retransmitted) Request. */
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if (icsk->icsk_retransmits == 0)
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dcb->dccpd_seq = dp->dccps_iss;
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fallthrough;
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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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fallthrough;
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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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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->inet_sport;
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dh->dccph_dport = inet->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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dccp_update_gss(sk, dcb->dccpd_seq);
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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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/*
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* Limit Ack window to ISS <= P.ackno <= GSS, so that
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* only Responses to Requests we sent are considered.
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*/
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dp->dccps_awl = dp->dccps_iss;
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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, 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(sk, skb, &inet->cork.fl);
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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-specific packet-size limits
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* @dp: socket to find packet size limits of
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*
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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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u32 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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* Leave enough headroom for common DCCP header options.
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* This only considers options which may appear on DCCP-Data packets, as
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* per table 3 in RFC 4340, 5.8. When running out of space for other
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* options (eg. Ack Vector which can take up to 255 bytes), it is better
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* to schedule a separate Ack. Thus we leave headroom for the following:
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* - 1 byte for Slow Receiver (11.6)
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* - 6 bytes for Timestamp (13.1)
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* - 10 bytes for Timestamp Echo (13.3)
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* - 8 bytes for NDP count (7.7, when activated)
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* - 6 bytes for Data Checksum (9.3)
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* - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled)
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*/
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cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 +
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(dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 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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struct socket_wq *wq;
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rcu_read_lock();
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wq = rcu_dereference(sk->sk_wq);
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if (skwq_has_sleeper(wq))
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wake_up_interruptible(&wq->wait);
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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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rcu_read_unlock();
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}
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/**
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* dccp_wait_for_ccid - Await CCID send permission
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* @sk: socket to wait for
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* @delay: timeout in jiffies
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*
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* This is used by CCIDs which need to delay the send time in process context.
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*/
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static int dccp_wait_for_ccid(struct sock *sk, unsigned long delay)
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{
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DEFINE_WAIT(wait);
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long remaining;
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prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
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sk->sk_write_pending++;
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release_sock(sk);
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remaining = schedule_timeout(delay);
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lock_sock(sk);
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sk->sk_write_pending--;
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finish_wait(sk_sleep(sk), &wait);
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if (signal_pending(current) || sk->sk_err)
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return -1;
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return remaining;
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}
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/**
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* dccp_xmit_packet - Send data packet under control of CCID
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* @sk: socket to send data packet on
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*
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* Transmits next-queued payload and informs CCID to account for the packet.
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*/
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static void dccp_xmit_packet(struct sock *sk)
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{
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int err, len;
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struct dccp_sock *dp = dccp_sk(sk);
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struct sk_buff *skb = dccp_qpolicy_pop(sk);
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if (unlikely(skb == NULL))
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return;
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len = skb->len;
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if (sk->sk_state == DCCP_PARTOPEN) {
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const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD;
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/*
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* See 8.1.5 - Handshake Completion.
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*
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* For robustness we resend Confirm options until the client has
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* entered OPEN. During the initial feature negotiation, the MPS
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* is smaller than usual, reduced by the Change/Confirm options.
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*/
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if (!list_empty(&dp->dccps_featneg) && len > cur_mps) {
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DCCP_WARN("Payload too large (%d) for featneg.\n", len);
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dccp_send_ack(sk);
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dccp_feat_list_purge(&dp->dccps_featneg);
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}
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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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DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK;
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} else if (dccp_ack_pending(sk)) {
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DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK;
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} else {
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DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATA;
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}
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err = dccp_transmit_skb(sk, skb);
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if (err)
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dccp_pr_debug("transmit_skb() returned err=%d\n", err);
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/*
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* Register this one as sent even if an error occurred. To the remote
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* end a local packet drop is indistinguishable from network loss, i.e.
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* any local drop will eventually be reported via receiver feedback.
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*/
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ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len);
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/*
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* If the CCID needs to transfer additional header options out-of-band
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* (e.g. Ack Vectors or feature-negotiation options), it activates this
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* flag to schedule a Sync. The Sync will automatically incorporate all
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* currently pending header options, thus clearing the backlog.
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*/
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if (dp->dccps_sync_scheduled)
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dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
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}
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/**
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* dccp_flush_write_queue - Drain queue at end of connection
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* @sk: socket to be drained
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* @time_budget: time allowed to drain the queue
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*
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* Since dccp_sendmsg queues packets without waiting for them to be sent, it may
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* happen that the TX queue is not empty at the end of a connection. We give the
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* HC-sender CCID a grace period of up to @time_budget jiffies. If this function
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* returns with a non-empty write queue, it will be purged later.
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*/
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void dccp_flush_write_queue(struct sock *sk, long *time_budget)
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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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long delay, rc;
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while (*time_budget > 0 && (skb = skb_peek(&sk->sk_write_queue))) {
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rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
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switch (ccid_packet_dequeue_eval(rc)) {
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case CCID_PACKET_WILL_DEQUEUE_LATER:
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/*
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* If the CCID determines when to send, the next sending
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* time is unknown or the CCID may not even send again
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* (e.g. remote host crashes or lost Ack packets).
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*/
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DCCP_WARN("CCID did not manage to send all packets\n");
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return;
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case CCID_PACKET_DELAY:
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delay = msecs_to_jiffies(rc);
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if (delay > *time_budget)
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return;
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rc = dccp_wait_for_ccid(sk, delay);
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if (rc < 0)
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return;
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*time_budget -= (delay - rc);
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/* check again if we can send now */
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break;
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case CCID_PACKET_SEND_AT_ONCE:
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dccp_xmit_packet(sk);
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break;
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case CCID_PACKET_ERR:
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skb_dequeue(&sk->sk_write_queue);
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kfree_skb(skb);
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dccp_pr_debug("packet discarded due to err=%ld\n", rc);
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}
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}
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}
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void dccp_write_xmit(struct sock *sk)
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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 = dccp_qpolicy_top(sk))) {
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int rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
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switch (ccid_packet_dequeue_eval(rc)) {
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case CCID_PACKET_WILL_DEQUEUE_LATER:
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return;
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case CCID_PACKET_DELAY:
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sk_reset_timer(sk, &dp->dccps_xmit_timer,
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jiffies + msecs_to_jiffies(rc));
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return;
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case CCID_PACKET_SEND_AT_ONCE:
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dccp_xmit_packet(sk);
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break;
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case CCID_PACKET_ERR:
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dccp_qpolicy_drop(sk, skb);
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dccp_pr_debug("packet discarded due to err=%d\n", rc);
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}
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}
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}
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/**
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* dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets
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* @sk: socket to perform retransmit on
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*
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* There are only four retransmittable packet types in DCCP:
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* - Request in client-REQUEST state (sec. 8.1.1),
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* - CloseReq in server-CLOSEREQ state (sec. 8.3),
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* - Close in node-CLOSING state (sec. 8.3),
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* - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()).
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* This function expects sk->sk_send_head to contain the original skb.
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*/
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int dccp_retransmit_skb(struct sock *sk)
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{
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WARN_ON(sk->sk_send_head == NULL);
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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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/* this count is used to distinguish original and retransmitted skb */
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inet_csk(sk)->icsk_retransmits++;
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return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
|
|
}
|
|
|
|
struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
|
|
struct request_sock *req)
|
|
{
|
|
struct dccp_hdr *dh;
|
|
struct dccp_request_sock *dreq;
|
|
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
|
|
sizeof(struct dccp_hdr_ext) +
|
|
sizeof(struct dccp_hdr_response);
|
|
struct sk_buff *skb;
|
|
|
|
/* sk is marked const to clearly express we dont hold socket lock.
|
|
* sock_wmalloc() will atomically change sk->sk_wmem_alloc,
|
|
* it is safe to promote sk to non const.
|
|
*/
|
|
skb = sock_wmalloc((struct sock *)sk, MAX_DCCP_HEADER, 1,
|
|
GFP_ATOMIC);
|
|
if (!skb)
|
|
return NULL;
|
|
|
|
skb_reserve(skb, MAX_DCCP_HEADER);
|
|
|
|
skb_dst_set(skb, dst_clone(dst));
|
|
|
|
dreq = dccp_rsk(req);
|
|
if (inet_rsk(req)->acked) /* increase GSS upon retransmission */
|
|
dccp_inc_seqno(&dreq->dreq_gss);
|
|
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
|
|
DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_gss;
|
|
|
|
/* 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 = htons(inet_rsk(req)->ir_num);
|
|
dh->dccph_dport = inet_rsk(req)->ir_rmt_port;
|
|
dh->dccph_doff = (dccp_header_size +
|
|
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
|
|
dh->dccph_type = DCCP_PKT_RESPONSE;
|
|
dh->dccph_x = 1;
|
|
dccp_hdr_set_seq(dh, dreq->dreq_gss);
|
|
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_gsr);
|
|
dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
|
|
|
|
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);
|
|
|
|
/* 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 *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;
|
|
|
|
skb_reserve(skb, sk->sk_prot->max_header);
|
|
|
|
/* 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;
|
|
|
|
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:
|
|
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_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_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;
|
|
|
|
/* 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);
|
|
}
|
|
|
|
/*
|
|
* Do all connect socket setups that can be done AF independent.
|
|
*/
|
|
int dccp_connect(struct sock *sk)
|
|
{
|
|
struct sk_buff *skb;
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
|
struct dst_entry *dst = __sk_dst_get(sk);
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
|
|
|
sk->sk_err = 0;
|
|
sock_reset_flag(sk, SOCK_DONE);
|
|
|
|
dccp_sync_mss(sk, dst_mtu(dst));
|
|
|
|
/* do not connect if feature negotiation setup fails */
|
|
if (dccp_feat_finalise_settings(dccp_sk(sk)))
|
|
return -EPROTO;
|
|
|
|
/* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
|
|
dp->dccps_gar = dp->dccps_iss;
|
|
|
|
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_transmit_skb(sk, dccp_skb_entail(sk, skb));
|
|
DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
|
|
|
|
/* Timer for repeating the REQUEST until an answer. */
|
|
icsk->icsk_retransmits = 0;
|
|
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;
|
|
|
|
/*
|
|
* Clear the flag in case the Sync was scheduled for out-of-band data,
|
|
* such as carrying a long Ack Vector.
|
|
*/
|
|
dccp_sk(sk)->dccps_sync_scheduled = 0;
|
|
|
|
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) {
|
|
skb = dccp_skb_entail(sk, skb);
|
|
/*
|
|
* 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);
|
|
}
|
|
dccp_transmit_skb(sk, skb);
|
|
}
|