24 files changed, 8490 insertions, 0 deletions

diff --git a/net/dccp/Kconfig b/net/dccp/Kconfig
new file mode 100644
index 00000000000..187ac182e24
--- /dev/null
+++ b/net/dccp/Kconfig
@@ -0,0 +1,50 @@
+menu "DCCP Configuration (EXPERIMENTAL)"
+	depends on INET && EXPERIMENTAL
+
+config IP_DCCP
+	tristate "The DCCP Protocol (EXPERIMENTAL)"
+	---help---
+	  Datagram Congestion Control Protocol
+
+	  From draft-ietf-dccp-spec-11 <http://www.icir.org/kohler/dcp/draft-ietf-dccp-spec-11.txt>.
+
+	  The Datagram Congestion Control Protocol (DCCP) is a transport
+	  protocol that implements bidirectional, unicast connections of
+	  congestion-controlled, unreliable datagrams. It should be suitable
+	  for use by applications such as streaming media, Internet telephony,
+	  and on-line games
+
+	  To compile this protocol support as a module, choose M here: the
+	  module will be called dccp.
+
+	  If in doubt, say N.
+
+config INET_DCCP_DIAG
+	depends on IP_DCCP && INET_DIAG
+	def_tristate y if (IP_DCCP = y && INET_DIAG = y)
+	def_tristate m
+
+source "net/dccp/ccids/Kconfig"
+
+menu "DCCP Kernel Hacking"
+	depends on IP_DCCP && DEBUG_KERNEL=y
+
+config IP_DCCP_DEBUG
+	bool "DCCP debug messages"
+	---help---
+	  Only use this if you're hacking DCCP.
+
+	  Just say N.
+
+config IP_DCCP_UNLOAD_HACK
+	depends on IP_DCCP=m && IP_DCCP_CCID3=m
+	bool "DCCP control sock unload hack"
+	---help---
+	  Enable this to be able to unload the dccp module when the it
+	  has only one refcount held, the control sock one. Just execute
+	  "rmmod dccp_ccid3 dccp"
+
+	  Just say N.
+endmenu
+
+endmenu
diff --git a/net/dccp/Makefile b/net/dccp/Makefile
new file mode 100644
index 00000000000..fb97bb04245
--- /dev/null
+++ b/net/dccp/Makefile
@@ -0,0 +1,10 @@
+obj-$(CONFIG_IP_DCCP) += dccp.o
+
+dccp-y := ccid.o input.o ipv4.o minisocks.o options.o output.o proto.o \
+	  timer.o
+
+obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o
+
+dccp_diag-y := diag.o
+
+obj-y += ccids/
diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
new file mode 100644
index 00000000000..9d8fc0e289e
--- /dev/null
+++ b/net/dccp/ccid.c
@@ -0,0 +1,139 @@
+/*
+ *  net/dccp/ccid.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  CCID infrastructure
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include "ccid.h"
+
+static struct ccid *ccids[CCID_MAX];
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
+static atomic_t ccids_lockct = ATOMIC_INIT(0);
+static DEFINE_SPINLOCK(ccids_lock);
+
+/*
+ * The strategy is: modifications ccids vector are short, do not sleep and
+ * veeery rare, but read access should be free of any exclusive locks.
+ */
+static void ccids_write_lock(void)
+{
+	spin_lock(&ccids_lock);
+	while (atomic_read(&ccids_lockct) != 0) {
+		spin_unlock(&ccids_lock);
+		yield();
+		spin_lock(&ccids_lock);
+	}
+}
+
+static inline void ccids_write_unlock(void)
+{
+	spin_unlock(&ccids_lock);
+}
+
+static inline void ccids_read_lock(void)
+{
+	atomic_inc(&ccids_lockct);
+	spin_unlock_wait(&ccids_lock);
+}
+
+static inline void ccids_read_unlock(void)
+{
+	atomic_dec(&ccids_lockct);
+}
+
+#else
+#define ccids_write_lock() do { } while(0)
+#define ccids_write_unlock() do { } while(0)
+#define ccids_read_lock() do { } while(0)
+#define ccids_read_unlock() do { } while(0)
+#endif
+
+int ccid_register(struct ccid *ccid)
+{
+	int err;
+
+	if (ccid->ccid_init == NULL)
+		return -1;
+
+	ccids_write_lock();
+	err = -EEXIST;
+	if (ccids[ccid->ccid_id] == NULL) {
+		ccids[ccid->ccid_id] = ccid;
+		err = 0;
+	}
+	ccids_write_unlock();
+	if (err == 0)
+		pr_info("CCID: Registered CCID %d (%s)\n",
+			ccid->ccid_id, ccid->ccid_name);
+	return err;
+}
+
+EXPORT_SYMBOL_GPL(ccid_register);
+
+int ccid_unregister(struct ccid *ccid)
+{
+	ccids_write_lock();
+	ccids[ccid->ccid_id] = NULL;
+	ccids_write_unlock();
+	pr_info("CCID: Unregistered CCID %d (%s)\n",
+		ccid->ccid_id, ccid->ccid_name);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(ccid_unregister);
+
+struct ccid *ccid_init(unsigned char id, struct sock *sk)
+{
+	struct ccid *ccid;
+
+#ifdef CONFIG_KMOD
+	if (ccids[id] == NULL)
+		request_module("net-dccp-ccid-%d", id);
+#endif
+	ccids_read_lock();
+
+	ccid = ccids[id];
+	if (ccid == NULL)
+		goto out;
+
+	if (!try_module_get(ccid->ccid_owner))
+		goto out_err;
+
+	if (ccid->ccid_init(sk) != 0)
+		goto out_module_put;
+out:
+	ccids_read_unlock();
+	return ccid;
+out_module_put:
+	module_put(ccid->ccid_owner);
+out_err:
+	ccid = NULL;
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(ccid_init);
+
+void ccid_exit(struct ccid *ccid, struct sock *sk)
+{
+	if (ccid == NULL)
+		return;
+
+	ccids_read_lock();
+
+	if (ccids[ccid->ccid_id] != NULL) {
+		if (ccid->ccid_exit != NULL)
+			ccid->ccid_exit(sk);
+		module_put(ccid->ccid_owner);
+	}
+
+	ccids_read_unlock();
+}
+
+EXPORT_SYMBOL_GPL(ccid_exit);
diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
new file mode 100644
index 00000000000..962f1e9e2f7
--- /dev/null
+++ b/net/dccp/ccid.h
@@ -0,0 +1,180 @@
+#ifndef _CCID_H
+#define _CCID_H
+/*
+ *  net/dccp/ccid.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  CCID infrastructure
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <net/sock.h>
+#include <linux/dccp.h>
+#include <linux/list.h>
+#include <linux/module.h>
+
+#define CCID_MAX 255
+
+struct ccid {
+	unsigned char	ccid_id;
+	const char	*ccid_name;
+	struct module	*ccid_owner;
+	int		(*ccid_init)(struct sock *sk);
+	void		(*ccid_exit)(struct sock *sk);
+	int		(*ccid_hc_rx_init)(struct sock *sk);
+	int		(*ccid_hc_tx_init)(struct sock *sk);
+	void		(*ccid_hc_rx_exit)(struct sock *sk);
+	void		(*ccid_hc_tx_exit)(struct sock *sk);
+	void		(*ccid_hc_rx_packet_recv)(struct sock *sk,
+						  struct sk_buff *skb);
+	int		(*ccid_hc_rx_parse_options)(struct sock *sk,
+						    unsigned char option,
+						    unsigned char len, u16 idx,
+						    unsigned char* value);
+	void		(*ccid_hc_rx_insert_options)(struct sock *sk,
+						     struct sk_buff *skb);
+	void		(*ccid_hc_tx_insert_options)(struct sock *sk,
+						     struct sk_buff *skb);
+	void		(*ccid_hc_tx_packet_recv)(struct sock *sk,
+						  struct sk_buff *skb);
+	int		(*ccid_hc_tx_parse_options)(struct sock *sk,
+						    unsigned char option,
+						    unsigned char len, u16 idx,
+						    unsigned char* value);
+	int		(*ccid_hc_tx_send_packet)(struct sock *sk,
+						  struct sk_buff *skb, int len);
+	void		(*ccid_hc_tx_packet_sent)(struct sock *sk, int more,
+						  int len);
+	void		(*ccid_hc_rx_get_info)(struct sock *sk,
+					       struct tcp_info *info);
+	void		(*ccid_hc_tx_get_info)(struct sock *sk,
+					       struct tcp_info *info);
+};
+
+extern int	   ccid_register(struct ccid *ccid);
+extern int	   ccid_unregister(struct ccid *ccid);
+
+extern struct ccid *ccid_init(unsigned char id, struct sock *sk);
+extern void	   ccid_exit(struct ccid *ccid, struct sock *sk);
+
+static inline void __ccid_get(struct ccid *ccid)
+{
+	__module_get(ccid->ccid_owner);
+}
+
+static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
+					 struct sk_buff *skb, int len)
+{
+	int rc = 0;
+	if (ccid->ccid_hc_tx_send_packet != NULL)
+		rc = ccid->ccid_hc_tx_send_packet(sk, skb, len);
+	return rc;
+}
+
+static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
+					  int more, int len)
+{
+	if (ccid->ccid_hc_tx_packet_sent != NULL)
+		ccid->ccid_hc_tx_packet_sent(sk, more, len);
+}
+
+static inline int ccid_hc_rx_init(struct ccid *ccid, struct sock *sk)
+{
+	int rc = 0;
+	if (ccid->ccid_hc_rx_init != NULL)
+		rc = ccid->ccid_hc_rx_init(sk);
+	return rc;
+}
+
+static inline int ccid_hc_tx_init(struct ccid *ccid, struct sock *sk)
+{
+	int rc = 0;
+	if (ccid->ccid_hc_tx_init != NULL)
+		rc = ccid->ccid_hc_tx_init(sk);
+	return rc;
+}
+
+static inline void ccid_hc_rx_exit(struct ccid *ccid, struct sock *sk)
+{
+	if (ccid->ccid_hc_rx_exit != NULL &&
+	    dccp_sk(sk)->dccps_hc_rx_ccid_private != NULL)
+		ccid->ccid_hc_rx_exit(sk);
+}
+
+static inline void ccid_hc_tx_exit(struct ccid *ccid, struct sock *sk)
+{
+	if (ccid->ccid_hc_tx_exit != NULL &&
+	    dccp_sk(sk)->dccps_hc_tx_ccid_private != NULL)
+		ccid->ccid_hc_tx_exit(sk);
+}
+
+static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
+					  struct sk_buff *skb)
+{
+	if (ccid->ccid_hc_rx_packet_recv != NULL)
+		ccid->ccid_hc_rx_packet_recv(sk, skb);
+}
+
+static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
+					  struct sk_buff *skb)
+{
+	if (ccid->ccid_hc_tx_packet_recv != NULL)
+		ccid->ccid_hc_tx_packet_recv(sk, skb);
+}
+
+static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
+					   unsigned char option,
+					   unsigned char len, u16 idx,
+					   unsigned char* value)
+{
+	int rc = 0;
+	if (ccid->ccid_hc_tx_parse_options != NULL)
+		rc = ccid->ccid_hc_tx_parse_options(sk, option, len, idx,
+						    value);
+	return rc;
+}
+
+static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
+					   unsigned char option,
+					   unsigned char len, u16 idx,
+					   unsigned char* value)
+{
+	int rc = 0;
+	if (ccid->ccid_hc_rx_parse_options != NULL)
+		rc = ccid->ccid_hc_rx_parse_options(sk, option, len, idx, value);
+	return rc;
+}
+
+static inline void ccid_hc_tx_insert_options(struct ccid *ccid, struct sock *sk,
+					     struct sk_buff *skb)
+{
+	if (ccid->ccid_hc_tx_insert_options != NULL)
+		ccid->ccid_hc_tx_insert_options(sk, skb);
+}
+
+static inline void ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
+					     struct sk_buff *skb)
+{
+	if (ccid->ccid_hc_rx_insert_options != NULL)
+		ccid->ccid_hc_rx_insert_options(sk, skb);
+}
+
+static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
+				       struct tcp_info *info)
+{
+	if (ccid->ccid_hc_rx_get_info != NULL)
+		ccid->ccid_hc_rx_get_info(sk, info);
+}
+
+static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
+				       struct tcp_info *info)
+{
+	if (ccid->ccid_hc_tx_get_info != NULL)
+		ccid->ccid_hc_tx_get_info(sk, info);
+}
+#endif /* _CCID_H */
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
new file mode 100644
index 00000000000..7684d83946a
--- /dev/null
+++ b/net/dccp/ccids/Kconfig
@@ -0,0 +1,29 @@
+menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
+	depends on IP_DCCP && EXPERIMENTAL
+
+config IP_DCCP_CCID3
+	tristate "CCID3 (TFRC) (EXPERIMENTAL)"
+	depends on IP_DCCP
+	---help---
+	  CCID 3 denotes TCP-Friendly Rate Control (TFRC), an equation-based
+	  rate-controlled congestion control mechanism.  TFRC is designed to
+	  be reasonably fair when competing for bandwidth with TCP-like flows,
+	  where a flow is "reasonably fair" if its sending rate is generally
+	  within a factor of two of the sending rate of a TCP flow under the
+	  same conditions.  However, TFRC has a much lower variation of
+	  throughput over time compared with TCP, which makes CCID 3 more
+	  suitable than CCID 2 for applications such streaming media where a
+	  relatively smooth sending rate is of importance.
+
+	  CCID 3 is further described in [CCID 3 PROFILE]. The TFRC
+	  congestion control algorithms were initially described in RFC 3448.
+
+	  This text was extracted from draft-ietf-dccp-spec-11.txt.
+	  
+	  If in doubt, say M.
+
+config IP_DCCP_TFRC_LIB
+	depends on IP_DCCP_CCID3
+	def_tristate IP_DCCP_CCID3
+
+endmenu
diff --git a/net/dccp/ccids/Makefile b/net/dccp/ccids/Makefile
new file mode 100644
index 00000000000..956f79f5074
--- /dev/null
+++ b/net/dccp/ccids/Makefile
@@ -0,0 +1,5 @@
+obj-$(CONFIG_IP_DCCP_CCID3) += dccp_ccid3.o
+
+dccp_ccid3-y := ccid3.o
+
+obj-y += lib/
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
new file mode 100644
index 00000000000..7bf3b3a91e9
--- /dev/null
+++ b/net/dccp/ccids/ccid3.c
@@ -0,0 +1,1221 @@
+/*
+ *  net/dccp/ccids/ccid3.c
+ *
+ *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
+ *
+ *  An implementation of the DCCP protocol
+ *
+ *  This code has been developed by the University of Waikato WAND
+ *  research group. For further information please see http://www.wand.net.nz/
+ *
+ *  This code also uses code from Lulea University, rereleased as GPL by its
+ *  authors:
+ *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
+ *  and to make it work as a loadable module in the DCCP stack written by
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
+ *
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  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.
+ */
+
+#include <linux/config.h>
+#include "../ccid.h"
+#include "../dccp.h"
+#include "lib/packet_history.h"
+#include "lib/loss_interval.h"
+#include "lib/tfrc.h"
+#include "ccid3.h"
+
+/*
+ * Reason for maths with 10 here is to avoid 32 bit overflow when a is big.
+ */
+static inline u32 usecs_div(const u32 a, const u32 b)
+{
+	const u32 tmp = a * (USEC_PER_SEC / 10);
+	return b > 20 ? tmp / (b / 10) : tmp;
+}
+
+static int ccid3_debug;
+
+#ifdef CCID3_DEBUG
+#define ccid3_pr_debug(format, a...) \
+	do { if (ccid3_debug) \
+		printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \
+	} while (0)
+#else
+#define ccid3_pr_debug(format, a...)
+#endif
+
+static struct dccp_tx_hist *ccid3_tx_hist;
+static struct dccp_rx_hist *ccid3_rx_hist;
+static struct dccp_li_hist *ccid3_li_hist;
+
+static int ccid3_init(struct sock *sk)
+{
+	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
+	return 0;
+}
+
+static void ccid3_exit(struct sock *sk)
+{
+	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
+}
+
+/* TFRC sender states */
+enum ccid3_hc_tx_states {
+       	TFRC_SSTATE_NO_SENT = 1,
+	TFRC_SSTATE_NO_FBACK,
+	TFRC_SSTATE_FBACK,
+	TFRC_SSTATE_TERM,
+};
+
+#ifdef CCID3_DEBUG
+static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
+{
+	static char *ccid3_state_names[] = {
+	[TFRC_SSTATE_NO_SENT]  = "NO_SENT",
+	[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
+	[TFRC_SSTATE_FBACK]    = "FBACK",
+	[TFRC_SSTATE_TERM]     = "TERM",
+	};
+
+	return ccid3_state_names[state];
+}
+#endif
+
+static inline void ccid3_hc_tx_set_state(struct sock *sk,
+					 enum ccid3_hc_tx_states state)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+	enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
+
+	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
+		       dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
+		       ccid3_tx_state_name(state));
+	WARN_ON(state == oldstate);
+	hctx->ccid3hctx_state = state;
+}
+
+/* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
+static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
+{
+	/*
+	 * If no feedback spec says t_ipi is 1 second (set elsewhere and then
+	 * doubles after every no feedback timer (separate function)
+	 */
+	if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
+		hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s,
+						  hctx->ccid3hctx_x);
+}
+
+/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
+static inline void ccid3_calc_new_delta(struct ccid3_hc_tx_sock *hctx)
+{
+	hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
+					   TFRC_OPSYS_HALF_TIME_GRAN);
+}
+
+/*
+ * Update X by
+ *    If (p > 0)
+ *       x_calc = calcX(s, R, p);
+ *       X = max(min(X_calc, 2 * X_recv), s / t_mbi);
+ *    Else
+ *       If (now - tld >= R)
+ *          X = max(min(2 * X, 2 * X_recv), s / R);
+ *          tld = now;
+ */ 
+static void ccid3_hc_tx_update_x(struct sock *sk)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+
+	/* To avoid large error in calcX */
+	if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
+		hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
+						     hctx->ccid3hctx_rtt,
+						     hctx->ccid3hctx_p);
+		hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
+							  2 * hctx->ccid3hctx_x_recv),
+					       (hctx->ccid3hctx_s /
+					        TFRC_MAX_BACK_OFF_TIME));
+	} else {
+		struct timeval now;
+
+		do_gettimeofday(&now);
+	       	if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
+		    hctx->ccid3hctx_rtt) {
+			hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv,
+								  hctx->ccid3hctx_x) * 2,
+						       usecs_div(hctx->ccid3hctx_s,
+							       	 hctx->ccid3hctx_rtt));
+			hctx->ccid3hctx_t_ld = now;
+		}
+	}
+}
+
+static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+	struct dccp_sock *dp = dccp_sk(sk);
+	unsigned long next_tmout = 0;
+	struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		/* Try again later. */
+		/* XXX: set some sensible MIB */
+		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+			       jiffies + HZ / 5);
+		goto out;
+	}
+
+	ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
+		       ccid3_tx_state_name(hctx->ccid3hctx_state));
+	
+	switch (hctx->ccid3hctx_state) {
+	case TFRC_SSTATE_TERM:
+		goto out;
+	case TFRC_SSTATE_NO_FBACK:
+		/* Halve send rate */
+		hctx->ccid3hctx_x /= 2;
+		if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s /
+					 TFRC_MAX_BACK_OFF_TIME))
+			hctx->ccid3hctx_x = (hctx->ccid3hctx_s /
+					     TFRC_MAX_BACK_OFF_TIME);
+
+		ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
+			       "bytes/s\n",
+			       dccp_role(sk), sk,
+			       ccid3_tx_state_name(hctx->ccid3hctx_state),
+			       hctx->ccid3hctx_x);
+		next_tmout = max_t(u32, 2 * usecs_div(hctx->ccid3hctx_s,
+						      hctx->ccid3hctx_x),
+					TFRC_INITIAL_TIMEOUT);
+		/*
+		 * FIXME - not sure above calculation is correct. See section
+		 * 5 of CCID3 11 should adjust tx_t_ipi and double that to
+		 * achieve it really
+		 */
+		break;
+	case TFRC_SSTATE_FBACK:
+		/*
+		 * Check if IDLE since last timeout and recv rate is less than
+		 * 4 packets per RTT
+		 */
+		if (!hctx->ccid3hctx_idle ||
+		    (hctx->ccid3hctx_x_recv >=
+		     4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
+			ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
+				       dccp_role(sk), sk,
+				       ccid3_tx_state_name(hctx->ccid3hctx_state));
+			/* Halve sending rate */
+
+			/*  If (X_calc > 2 * X_recv)
+			 *    X_recv = max(X_recv / 2, s / (2 * t_mbi));
+			 *  Else
+			 *    X_recv = X_calc / 4;
+			 */
+			BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
+			       hctx->ccid3hctx_x_calc == 0);
+
+			/* check also if p is zero -> x_calc is infinity? */
+			if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
+			    hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
+				hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
+								    hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME));
+			else
+				hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
+
+			/* Update sending rate */
+			ccid3_hc_tx_update_x(sk);
+		}
+		/*
+		 * Schedule no feedback timer to expire in
+		 * max(4 * R, 2 * s / X)
+		 */
+		next_tmout = max_t(u32, hctx->ccid3hctx_t_rto, 
+					2 * usecs_div(hctx->ccid3hctx_s,
+						      hctx->ccid3hctx_x));
+		break;
+	default:
+		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
+		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
+		dump_stack();
+		goto out;
+	}
+
+	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, 
+		      jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
+	hctx->ccid3hctx_idle = 1;
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+static int ccid3_hc_tx_send_packet(struct sock *sk,
+				   struct sk_buff *skb, int len)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+	struct dccp_tx_hist_entry *new_packet;
+	struct timeval now;
+	long delay;
+	int rc = -ENOTCONN;
+
+	/* Check if pure ACK or Terminating*/
+
+	/*
+	 * XXX: We only call this function for DATA and DATAACK, on, these
+	 * packets can have zero length, but why the comment about "pure ACK"?
+	 */
+	if (hctx == NULL || len == 0 ||
+	    hctx->ccid3hctx_state == TFRC_SSTATE_TERM)
+		goto out;
+
+	/* See if last packet allocated was not sent */
+	new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
+	if (new_packet == NULL || new_packet->dccphtx_sent) {
+		new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
+						    SLAB_ATOMIC);
+
+		rc = -ENOBUFS;
+		if (new_packet == NULL) {
+			ccid3_pr_debug("%s, sk=%p, not enough mem to add "
+				       "to history, send refused\n",
+				       dccp_role(sk), sk);
+			goto out;
+		}
+
+		dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
+	}
+
+	do_gettimeofday(&now);
+
+	switch (hctx->ccid3hctx_state) {
+	case TFRC_SSTATE_NO_SENT:
+		ccid3_pr_debug("%s, sk=%p, first packet(%llu)\n",
+			       dccp_role(sk), sk, dp->dccps_gss);
+
+		hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
+		hctx->ccid3hctx_no_feedback_timer.data     = (unsigned long)sk;
+		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+			       jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
+		hctx->ccid3hctx_last_win_count	 = 0;
+		hctx->ccid3hctx_t_last_win_count = now;
+		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
+		hctx->ccid3hctx_t_ipi = TFRC_INITIAL_TIMEOUT;
+
+		/* Set nominal send time for initial packet */
+		hctx->ccid3hctx_t_nom = now;
+		timeval_add_usecs(&hctx->ccid3hctx_t_nom,
+				  hctx->ccid3hctx_t_ipi);
+		ccid3_calc_new_delta(hctx);
+		rc = 0;
+		break;
+	case TFRC_SSTATE_NO_FBACK:
+	case TFRC_SSTATE_FBACK:
+		delay = (timeval_delta(&now, &hctx->ccid3hctx_t_nom) -
+		         hctx->ccid3hctx_delta);
+		ccid3_pr_debug("send_packet delay=%ld\n", delay);
+		delay /= -1000;
+		/* divide by -1000 is to convert to ms and get sign right */
+		rc = delay > 0 ? delay : 0;
+		break;
+	default:
+		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
+		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
+		dump_stack();
+		rc = -EINVAL;
+		break;
+	}
+
+	/* Can we send? if so add options and add to packet history */
+	if (rc == 0)
+		new_packet->dccphtx_ccval =
+			DCCP_SKB_CB(skb)->dccpd_ccval =
+				hctx->ccid3hctx_last_win_count;
+out:
+	return rc;
+}
+
+static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+	struct timeval now;
+
+	BUG_ON(hctx == NULL);
+
+	if (hctx->ccid3hctx_state == TFRC_SSTATE_TERM) {
+		ccid3_pr_debug("%s, sk=%p, while state is TFRC_SSTATE_TERM!\n",
+			       dccp_role(sk), sk);
+		return;
+	}
+
+	do_gettimeofday(&now);
+
+	/* check if we have sent a data packet */
+	if (len > 0) {
+		unsigned long quarter_rtt;
+		struct dccp_tx_hist_entry *packet;
+
+		packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
+		if (packet == NULL) {
+			printk(KERN_CRIT "%s: packet doesn't exists in "
+					 "history!\n", __FUNCTION__);
+			return;
+		}
+		if (packet->dccphtx_sent) {
+			printk(KERN_CRIT "%s: no unsent packet in history!\n",
+			       __FUNCTION__);
+			return;
+		}
+		packet->dccphtx_tstamp = now;
+		packet->dccphtx_seqno  = dp->dccps_gss;
+		/*
+		 * Check if win_count have changed
+		 * Algorithm in "8.1. Window Counter Valuer" in
+		 * draft-ietf-dccp-ccid3-11.txt
+		 */
+		quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
+		if (likely(hctx->ccid3hctx_rtt > 8))
+			quarter_rtt /= hctx->ccid3hctx_rtt / 4;
+
+		if (quarter_rtt > 0) {
+			hctx->ccid3hctx_t_last_win_count = now;
+			hctx->ccid3hctx_last_win_count	 = (hctx->ccid3hctx_last_win_count +
+							    min_t(unsigned long, quarter_rtt, 5)) % 16;
+			ccid3_pr_debug("%s, sk=%p, window changed from "
+				       "%u to %u!\n",
+				       dccp_role(sk), sk,
+				       packet->dccphtx_ccval,
+				       hctx->ccid3hctx_last_win_count);
+		}
+
+		hctx->ccid3hctx_idle = 0;
+		packet->dccphtx_rtt  = hctx->ccid3hctx_rtt;
+		packet->dccphtx_sent = 1;
+	} else
+		ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
+			       dccp_role(sk), sk, dp->dccps_gss);
+
+	switch (hctx->ccid3hctx_state) {
+	case TFRC_SSTATE_NO_SENT:
+		/* if first wasn't pure ack */
+		if (len != 0)
+			printk(KERN_CRIT "%s: %s, First packet sent is noted "
+					 "as a data packet\n",
+			       __FUNCTION__, dccp_role(sk));
+		return;
+	case TFRC_SSTATE_NO_FBACK:
+	case TFRC_SSTATE_FBACK:
+		if (len > 0) {
+			hctx->ccid3hctx_t_nom = now;
+			ccid3_calc_new_t_ipi(hctx);
+			ccid3_calc_new_delta(hctx);
+			timeval_add_usecs(&hctx->ccid3hctx_t_nom,
+					  hctx->ccid3hctx_t_ipi);
+		}
+		break;
+	default:
+		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
+		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
+		dump_stack();
+		break;
+	}
+}
+
+static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+	struct ccid3_options_received *opt_recv;
+	struct dccp_tx_hist_entry *packet;
+	unsigned long next_tmout; 
+	u32 t_elapsed;
+	u32 pinv;
+	u32 x_recv;
+	u32 r_sample;
+
+	if (hctx == NULL)
+		return;
+
+	if (hctx->ccid3hctx_state == TFRC_SSTATE_TERM) {
+		ccid3_pr_debug("%s, sk=%p, received a packet when "
+			       "terminating!\n", dccp_role(sk), sk);
+		return;
+	}
+
+	/* we are only interested in ACKs */
+	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
+	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
+		return;
+
+	opt_recv = &hctx->ccid3hctx_options_received;
+
+	t_elapsed = dp->dccps_options_received.dccpor_elapsed_time;
+	x_recv = opt_recv->ccid3or_receive_rate;
+	pinv = opt_recv->ccid3or_loss_event_rate;
+
+	switch (hctx->ccid3hctx_state) {
+	case TFRC_SSTATE_NO_SENT:
+		/* FIXME: what to do here? */
+		return;
+	case TFRC_SSTATE_NO_FBACK:
+	case TFRC_SSTATE_FBACK:
+		/* Calculate new round trip sample by
+		 * R_sample = (now - t_recvdata) - t_delay */
+		/* get t_recvdata from history */
+		packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
+						 DCCP_SKB_CB(skb)->dccpd_ack_seq);
+		if (packet == NULL) {
+			ccid3_pr_debug("%s, sk=%p, seqno %llu(%s) does't "
+				       "exist in history!\n",
+				       dccp_role(sk), sk,
+				       DCCP_SKB_CB(skb)->dccpd_ack_seq,
+				       dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
+			return;
+		}
+
+		/* Update RTT */
+		r_sample = timeval_now_delta(&packet->dccphtx_tstamp);
+		/* FIXME: */
+		// r_sample -= usecs_to_jiffies(t_elapsed * 10);
+
+		/* Update RTT estimate by 
+		 * If (No feedback recv)
+		 *    R = R_sample;
+		 * Else
+		 *    R = q * R + (1 - q) * R_sample;
+		 *
+		 * q is a constant, RFC 3448 recomments 0.9
+		 */
+		if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
+			ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
+			hctx->ccid3hctx_rtt = r_sample;
+		} else
+			hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
+					      r_sample / 10;
+
+		ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
+			       "r_sample=%us\n", dccp_role(sk), sk,
+			       hctx->ccid3hctx_rtt, r_sample);
+
+		/* Update timeout interval */
+		hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
+					      USEC_PER_SEC);
+
+		/* Update receive rate */
+		hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
+