/*- * Copyright (c) 2007-2008 * Swinburne University of Technology, Melbourne, Australia. * Copyright (c) 2009-2010 Lawrence Stewart * 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * 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");