1 files changed, 340 insertions, 0 deletions
diff --git a/sys/netinet/cc/cc.c b/sys/netinet/cc/cc.c
new file mode 100644
index 000000000000..4643ca40105e
--- /dev/null
+++ b/sys/netinet/cc/cc.c
@@ -0,0 +1,340 @@
+/*-
+ * Copyright (c) 2007-2008
+ *	Swinburne University of Technology, Melbourne, Australia.
+ * Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org>
+ * Copyright (c) 2010 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed at the Centre for Advanced Internet
+ * Architectures, Swinburne University, by Lawrence Stewart and James Healy,
+ * made possible in part by a grant from the Cisco University Research Program
+ * Fund at Community Foundation Silicon Valley.
+ *
+ * Portions of this software were developed at the Centre for Advanced
+ * Internet Architectures, Swinburne University of Technology, Melbourne,
+ * Australia by David Hayes under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * This software was first released in 2007 by James Healy and Lawrence Stewart
+ * whilst working on the NewTCP research project at Swinburne University's
+ * Centre for Advanced Internet Architectures, Melbourne, Australia, which was
+ * made possible in part by a grant from the Cisco University Research Program
+ * Fund at Community Foundation Silicon Valley. More details are available at:
+ *   http://caia.swin.edu.au/urp/newtcp/
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/libkern.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/queue.h>
+#include <sys/rwlock.h>
+#include <sys/sbuf.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/sysctl.h>
+
+#include <net/if.h>
+#include <net/if_var.h>
+
+#include <netinet/cc.h>
+#include <netinet/in.h>
+#include <netinet/in_pcb.h>
+#include <netinet/tcp_var.h>
+
+#include <netinet/cc/cc_module.h>
+
+/*
+ * List of available cc algorithms on the current system. First element
+ * is used as the system default CC algorithm.
+ */
+struct cc_head cc_list = STAILQ_HEAD_INITIALIZER(cc_list);
+
+/* Protects the cc_list TAILQ. */
+struct rwlock cc_list_lock;
+
+/*
+ * Set the default CC algorithm to new_default. The default is identified
+ * by being the first element in the cc_list TAILQ.
+ */
+static void
+cc_set_default(struct cc_algo *new_default)
+{
+	CC_LIST_WLOCK_ASSERT();
+
+	/*
+	 * Make the requested system default CC algorithm the first element in
+	 * the list if it isn't already.
+	 */
+	if (new_default != CC_DEFAULT()) {
+		STAILQ_REMOVE(&cc_list, new_default, cc_algo, entries);
+		STAILQ_INSERT_HEAD(&cc_list, new_default, entries);
+	}
+}
+
+/*
+ * Sysctl handler to show and change the default CC algorithm.
+ */
+static int
+cc_default_algo(SYSCTL_HANDLER_ARGS)
+{
+	struct cc_algo *funcs;
+	int err, found;
+
+	err = found = 0;
+
+	if (req->newptr == NULL) {
+		char default_cc[TCP_CA_NAME_MAX];
+
+		/* Just print the current default. */
+		CC_LIST_RLOCK();
+		strlcpy(default_cc, CC_DEFAULT()->name, TCP_CA_NAME_MAX);
+		CC_LIST_RUNLOCK();
+		err = sysctl_handle_string(oidp, default_cc, 1, req);
+	} else {
+		/* Find algo with specified name and set it to default. */
+		CC_LIST_WLOCK();
+		STAILQ_FOREACH(funcs, &cc_list, entries) {
+			if (strncmp((char *)req->newptr, funcs->name,
+			    TCP_CA_NAME_MAX) == 0) {
+				found = 1;
+				cc_set_default(funcs);
+			}
+		}
+		CC_LIST_WUNLOCK();
+
+		if (!found)
+			err = ESRCH;
+	}
+
+	return (err);
+}
+
+/*
+ * Sysctl handler to display the list of available CC algorithms.
+ */
+static int
+cc_list_available(SYSCTL_HANDLER_ARGS)
+{
+	struct cc_algo *algo;
+	struct sbuf *s;
+	int err, first;
+
+	err = 0;
+	first = 1;
+	s = sbuf_new(NULL, NULL, TCP_CA_NAME_MAX, SBUF_AUTOEXTEND);
+
+	if (s == NULL)
+		return (ENOMEM);
+
+	CC_LIST_RLOCK();
+	STAILQ_FOREACH(algo, &cc_list, entries) {
+		err = sbuf_printf(s, first ? "%s" : ", %s", algo->name);
+		if (err)
+			break;
+		first = 0;
+	}
+	CC_LIST_RUNLOCK();
+
+	if (!err) {
+		sbuf_finish(s);
+		err = sysctl_handle_string(oidp, sbuf_data(s), 1, req);
+	}
+
+	sbuf_delete(s);
+	return (err);
+}
+
+/*
+ * Initialise CC subsystem on system boot.
+ */
+void
+cc_init()
+{
+	CC_LIST_LOCK_INIT();
+	STAILQ_INIT(&cc_list);
+}
+
+/*
+ * Returns non-zero on success, 0 on failure.
+ */
+int
+cc_deregister_algo(struct cc_algo *remove_cc)
+{
+	struct cc_algo *funcs, *tmpfuncs;
+	struct tcpcb *tp;
+	struct inpcb *inp;
+	int err;
+
+	err = ENOENT;
+
+	/* Never allow newreno to be deregistered. */
+	if (&newreno_cc_algo == remove_cc)
+		return (EPERM);
+
+	/* Remove algo from cc_list so that new connections can't use it. */
+	CC_LIST_WLOCK();
+	STAILQ_FOREACH_SAFE(funcs, &cc_list, entries, tmpfuncs) {
+		if (funcs == remove_cc) {
+			/*
+			 * If we're removing the current system default,
+			 * reset the default to newreno.
+			 */
+			if (strncmp(CC_DEFAULT()->name, remove_cc->name,
+			    TCP_CA_NAME_MAX) == 0)
+				cc_set_default(&newreno_cc_algo);
+
+			STAILQ_REMOVE(&cc_list, funcs, cc_algo, entries);
+			err = 0;
+			break;
+		}
+	}
+	CC_LIST_WUNLOCK();
+	
+	if (!err) {
+		/*
+		 * Check all active control blocks and change any that are
+		 * using this algorithm back to newreno. If the algorithm that
+		 * was in use requires cleanup code to be run, call it.
+		 *
+		 * New connections already part way through being initialised
+		 * with the CC algo we're removing will not race with this code
+		 * because the INP_INFO_WLOCK is held during initialisation.
+		 * We therefore don't enter the loop below until the connection
+		 * list has stabilised.
+		 */
+		INP_INFO_RLOCK(&V_tcbinfo);
+		LIST_FOREACH(inp, &V_tcb, inp_list) {
+			INP_WLOCK(inp);
+			/* Important to skip tcptw structs. */
+			if (!(inp->inp_flags & INP_TIMEWAIT) &&
+			    (tp = intotcpcb(inp)) != NULL) {
+				/*
+				 * By holding INP_WLOCK here, we are
+				 * assured that the connection is not
+				 * currently executing inside the CC
+				 * module's functions i.e. it is safe to
+				 * make the switch back to newreno.
+				 */
+				if (CC_ALGO(tp) == remove_cc) {
+					tmpfuncs = CC_ALGO(tp);
+					/* Newreno does not require any init. */
+					CC_ALGO(tp) = &newreno_cc_algo;
+					if (tmpfuncs->cb_destroy != NULL)
+						tmpfuncs->cb_destroy(tp->ccv);
+				}
+			}
+			INP_WUNLOCK(inp);
+		}
+		INP_INFO_RUNLOCK(&V_tcbinfo);
+	}
+
+	return (err);
+}
+
+/*
+ * Returns 0 on success, non-zero on failure.
+ */
+int
+cc_register_algo(struct cc_algo *add_cc)
+{
+	struct cc_algo *funcs;
+	int err;
+
+	err = 0;
+
+	/*
+	 * Iterate over list of registered CC algorithms and make sure
+	 * we're not trying to add a duplicate.
+	 */
+	CC_LIST_WLOCK();
+	STAILQ_FOREACH(funcs, &cc_list, entries) {
+		if (funcs == add_cc || strncmp(funcs->name, add_cc->name,
+		    TCP_CA_NAME_MAX) == 0)
+			err = EEXIST;
+	}
+
+	if (!err)
+		STAILQ_INSERT_TAIL(&cc_list, add_cc, entries);
+
+	CC_LIST_WUNLOCK();
+
+	return (err);
+}
+
+/*
+ * Handles kld related events. Returns 0 on success, non-zero on failure.
+ */
+int
+cc_modevent(module_t mod, int event_type, void *data)
+{
+	struct cc_algo *algo;
+	int err;
+
+	err = 0;
+	algo = (struct cc_algo *)data;
+
+	switch(event_type) {
+	case MOD_LOAD:
+		if (algo->mod_init != NULL)
+			err = algo->mod_init();
+		if (!err)
+			err = cc_register_algo(algo);
+		break;
+
+	case MOD_QUIESCE:
+	case MOD_SHUTDOWN:
+	case MOD_UNLOAD:
+		err = cc_deregister_algo(algo);
+		if (!err && algo->mod_destroy != NULL)
+			algo->mod_destroy();
+		if (err == ENOENT)
+			err = 0;
+		break;
+
+	default:
+		err = EINVAL;
+		break;
+	}
+
+	return (err);
+}
+
+/* Declare sysctl tree and populate it. */
+SYSCTL_NODE(_net_inet_tcp, OID_AUTO, cc, CTLFLAG_RW, NULL,
+    "congestion control related settings");
+
+SYSCTL_PROC(_net_inet_tcp_cc, OID_AUTO, algorithm, CTLTYPE_STRING|CTLFLAG_RW,
+    NULL, 0, cc_default_algo, "A", "default congestion control algorithm");
+
+SYSCTL_PROC(_net_inet_tcp_cc, OID_AUTO, available, CTLTYPE_STRING|CTLFLAG_RD,
+    NULL, 0, cc_list_available, "A",
+    "list available congestion control algorithms");