v4.19.13 snapshot.
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
new file mode 100644
index 0000000..1af0116
--- /dev/null
+++ b/net/dccp/ccids/ccid2.h
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _DCCP_CCID2_H_
+#define _DCCP_CCID2_H_
+
+#include <linux/timer.h>
+#include <linux/types.h>
+#include "../ccid.h"
+#include "../dccp.h"
+
+/*
+ * CCID-2 timestamping faces the same issues as TCP timestamping.
+ * Hence we reuse/share as much of the code as possible.
+ */
+#define ccid2_jiffies32 ((u32)jiffies)
+
+/* NUMDUPACK parameter from RFC 4341, p. 6 */
+#define NUMDUPACK 3
+
+struct ccid2_seq {
+ u64 ccid2s_seq;
+ u32 ccid2s_sent;
+ int ccid2s_acked;
+ struct ccid2_seq *ccid2s_prev;
+ struct ccid2_seq *ccid2s_next;
+};
+
+#define CCID2_SEQBUF_LEN 1024
+#define CCID2_SEQBUF_MAX 128
+
+/*
+ * Multiple of congestion window to keep the sequence window at
+ * (RFC 4340 7.5.2)
+ */
+#define CCID2_WIN_CHANGE_FACTOR 5
+
+/**
+ * struct ccid2_hc_tx_sock - CCID2 TX half connection
+ * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
+ * @tx_packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
+ * @tx_srtt: smoothed RTT estimate, scaled by 2^3
+ * @tx_mdev: smoothed RTT variation, scaled by 2^2
+ * @tx_mdev_max: maximum of @mdev during one flight
+ * @tx_rttvar: moving average/maximum of @mdev_max
+ * @tx_rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
+ * @tx_rtt_seq: to decay RTTVAR at most once per flight
+ * @tx_cwnd_used: actually used cwnd, W_used of RFC 2861
+ * @tx_expected_wnd: moving average of @tx_cwnd_used
+ * @tx_cwnd_stamp: to track idle periods in CWV
+ * @tx_lsndtime: last time (in jiffies) a data packet was sent
+ * @tx_rpseq: last consecutive seqno
+ * @tx_rpdupack: dupacks since rpseq
+ * @tx_av_chunks: list of Ack Vectors received on current skb
+ */
+struct ccid2_hc_tx_sock {
+ u32 tx_cwnd;
+ u32 tx_ssthresh;
+ u32 tx_pipe;
+ u32 tx_packets_acked;
+ struct ccid2_seq *tx_seqbuf[CCID2_SEQBUF_MAX];
+ int tx_seqbufc;
+ struct ccid2_seq *tx_seqh;
+ struct ccid2_seq *tx_seqt;
+
+ /* RTT measurement: variables/principles are the same as in TCP */
+ u32 tx_srtt,
+ tx_mdev,
+ tx_mdev_max,
+ tx_rttvar,
+ tx_rto;
+ u64 tx_rtt_seq:48;
+ struct timer_list tx_rtotimer;
+ struct sock *sk;
+
+ /* Congestion Window validation (optional, RFC 2861) */
+ u32 tx_cwnd_used,
+ tx_expected_wnd,
+ tx_cwnd_stamp,
+ tx_lsndtime;
+
+ u64 tx_rpseq;
+ int tx_rpdupack;
+ u32 tx_last_cong;
+ u64 tx_high_ack;
+ struct list_head tx_av_chunks;
+};
+
+static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
+{
+ return hc->tx_pipe >= hc->tx_cwnd;
+}
+
+/*
+ * Convert RFC 3390 larger initial window into an equivalent number of packets.
+ * This is based on the numbers specified in RFC 5681, 3.1.
+ */
+static inline u32 rfc3390_bytes_to_packets(const u32 smss)
+{
+ return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
+}
+
+/**
+ * struct ccid2_hc_rx_sock - Receiving end of CCID-2 half-connection
+ * @rx_num_data_pkts: number of data packets received since last feedback
+ */
+struct ccid2_hc_rx_sock {
+ u32 rx_num_data_pkts;
+};
+
+static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
+{
+ return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
+}
+
+static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
+{
+ return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
+}
+#endif /* _DCCP_CCID2_H_ */