sys/netinet/tcp_fastopen.c

   1 /*-
   2  * Copyright (c) 2015-2017 Patrick Kelsey
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 /*
  28  * This is an implementation of TCP Fast Open (TFO) [RFC7413]. To include
  29  * this code, add the following line to your kernel config:
  30  *
  31  * options TCP_RFC7413
  32  *
  33  *
  34  * The generated TFO cookies are the 64-bit output of
  35  * SipHash24(key=<16-byte-key>, msg=<client-ip>).  Multiple concurrent valid
  36  * keys are supported so that time-based rolling cookie invalidation
  37  * policies can be implemented in the system.  The default number of
  38  * concurrent keys is 2.  This can be adjusted in the kernel config as
  39  * follows:
  40  *
  41  * options TCP_RFC7413_MAX_KEYS=<num-keys>
  42  *
  43  *
  44  * In addition to the facilities defined in RFC7413, this implementation
  45  * supports a pre-shared key (PSK) mode of operation in which the TFO server
  46  * requires the client to be in posession of a shared secret in order for
  47  * the client to be able to successfully open TFO connections with the
  48  * server.  This is useful, for example, in environments where TFO servers
  49  * are exposed to both internal and external clients and only wish to allow
  50  * TFO connections from internal clients.
  51  *
  52  * In the PSK mode of operation, the server generates and sends TFO cookies
  53  * to requesting clients as usual.  However, when validating cookies
  54  * received in TFO SYNs from clients, the server requires the
  55  * client-supplied cookie to equal SipHash24(key=<16-byte-psk>,
  56  * msg=<cookie-sent-to-client>).
  57  *
  58  * Multiple concurrent valid pre-shared keys are supported so that
  59  * time-based rolling PSK invalidation policies can be implemented in the
  60  * system.  The default number of concurrent pre-shared keys is 2.  This can
  61  * be adjusted in the kernel config as follows:
  62  *
  63  * options TCP_RFC7413_MAX_PSKS=<num-psks>
  64  *
  65  *
  66  * The following TFO-specific sysctls are defined:
  67  *
  68  * net.inet.tcp.fastopen.acceptany (RW, default 0)
  69  *     When non-zero, all client-supplied TFO cookies will be considered to
  70  *     be valid.
  71  *
  72  * net.inet.tcp.fastopen.autokey (RW, default 120)
  73  *     When this and net.inet.tcp.fastopen.server_enable are non-zero, a new
  74  *     key will be automatically generated after this many seconds.
  75  *
  76  * net.inet.tcp.fastopen.ccache_bucket_limit
  77  *                     (RWTUN, default TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT)
  78  *     The maximum number of entries in a client cookie cache bucket.
  79  *
  80  * net.inet.tcp.fastopen.ccache_buckets
  81  *                          (RDTUN, default TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT)
  82  *     The number of client cookie cache buckets.
  83  *
  84  * net.inet.tcp.fastopen.ccache_list (RO)
  85  *     Print the client cookie cache.
  86  *
  87  * net.inet.tcp.fastopen.client_enable (RW, default 0)
  88  *     When zero, no new active (i.e., client) TFO connections can be
  89  *     created.  On the transition from enabled to disabled, the client
  90  *     cookie cache is cleared and disabled.  The transition from enabled to
  91  *     disabled does not affect any active TFO connections in progress; it
  92  *     only prevents new ones from being made.
  93  *
  94  * net.inet.tcp.fastopen.keylen (RD)
  95  *     The key length in bytes.
  96  *
  97  * net.inet.tcp.fastopen.maxkeys (RD)
  98  *     The maximum number of keys supported.
  99  *
 100  * net.inet.tcp.fastopen.maxpsks (RD)
 101  *     The maximum number of pre-shared keys supported.
 102  *
 103  * net.inet.tcp.fastopen.numkeys (RD)
 104  *     The current number of keys installed.
 105  *
 106  * net.inet.tcp.fastopen.numpsks (RD)
 107  *     The current number of pre-shared keys installed.
 108  *
 109  * net.inet.tcp.fastopen.path_disable_time
 110  *                          (RW, default TCP_FASTOPEN_PATH_DISABLE_TIME_DEFAULT)
 111  *     When a failure occurs while trying to create a new active (i.e.,
 112  *     client) TFO connection, new active connections on the same path, as
 113  *     determined by the tuple {client_ip, server_ip, server_port}, will be
 114  *     forced to be non-TFO for this many seconds.  Note that the path
 115  *     disable mechanism relies on state stored in client cookie cache
 116  *     entries, so it is possible for the disable time for a given path to
 117  *     be reduced if the corresponding client cookie cache entry is reused
 118  *     due to resource pressure before the disable period has elapsed.
 119  *
 120  * net.inet.tcp.fastopen.psk_enable (RW, default 0)
 121  *     When non-zero, pre-shared key (PSK) mode is enabled for all TFO
 122  *     servers.  On the transition from enabled to disabled, all installed
 123  *     pre-shared keys are removed.
 124  *
 125  * net.inet.tcp.fastopen.server_enable (RW, default 0)
 126  *     When zero, no new passive (i.e., server) TFO connections can be
 127  *     created.  On the transition from enabled to disabled, all installed
 128  *     keys and pre-shared keys are removed.  On the transition from
 129  *     disabled to enabled, if net.inet.tcp.fastopen.autokey is non-zero and
 130  *     there are no keys installed, a new key will be generated immediately.
 131  *     The transition from enabled to disabled does not affect any passive
 132  *     TFO connections in progress; it only prevents new ones from being
 133  *     made.
 134  *
 135  * net.inet.tcp.fastopen.setkey (WR)
 136  *     Install a new key by writing net.inet.tcp.fastopen.keylen bytes to
 137  *     this sysctl.
 138  *
 139  * net.inet.tcp.fastopen.setpsk (WR)
 140  *     Install a new pre-shared key by writing net.inet.tcp.fastopen.keylen
 141  *     bytes to this sysctl.
 142  *
 143  * In order for TFO connections to be created via a listen socket, that
 144  * socket must have the TCP_FASTOPEN socket option set on it.  This option
 145  * can be set on the socket either before or after the listen() is invoked.
 146  * Clearing this option on a listen socket after it has been set has no
 147  * effect on existing TFO connections or TFO connections in progress; it
 148  * only prevents new TFO connections from being made.
 149  *
 150  * For passively-created sockets, the TCP_FASTOPEN socket option can be
 151  * queried to determine whether the connection was established using TFO.
 152  * Note that connections that are established via a TFO SYN, but that fall
 153  * back to using a non-TFO SYN|ACK will have the TCP_FASTOPEN socket option
 154  * set.
 155  *
 156  * Per the RFC, this implementation limits the number of TFO connections
 157  * that can be in the SYN_RECEIVED state on a per listen-socket basis.
 158  * Whenever this limit is exceeded, requests for new TFO connections are
 159  * serviced as non-TFO requests.  Without such a limit, given a valid TFO
 160  * cookie, an attacker could keep the listen queue in an overflow condition
 161  * using a TFO SYN flood.  This implementation sets the limit at half the
 162  * configured listen backlog.
 163  *
 164  */
 165
 166 #include <sys/cdefs.h>
 167 #include "opt_inet.h"
 168
 169 #include <sys/param.h>
 170 #include <sys/jail.h>
 171 #include <sys/kernel.h>
 172 #include <sys/hash.h>
 173 #include <sys/limits.h>
 174 #include <sys/lock.h>
 175 #include <sys/proc.h>
 176 #include <sys/rmlock.h>
 177 #include <sys/sbuf.h>
 178 #include <sys/socket.h>
 179 #include <sys/socketvar.h>
 180 #include <sys/sysctl.h>
 181 #include <sys/systm.h>
 182
 183 #include <crypto/siphash/siphash.h>
 184
 185 #include <net/vnet.h>
 186
 187 #include <netinet/in.h>
 188 #include <netinet/in_pcb.h>
 189 #include <netinet/tcp_var.h>
 190 #include <netinet/tcp_fastopen.h>
 191
 192 #define TCP_FASTOPEN_KEY_LEN    SIPHASH_KEY_LENGTH
 193
 194 #if TCP_FASTOPEN_PSK_LEN != TCP_FASTOPEN_KEY_LEN
 195 #error TCP_FASTOPEN_PSK_LEN must be equal to TCP_FASTOPEN_KEY_LEN
 196 #endif
 197
 198 /*
 199  * Because a PSK-mode setsockopt() uses tcpcb.t_tfo_cookie.client to hold
 200  * the PSK until the connect occurs.
 201  */
 202 #if TCP_FASTOPEN_MAX_COOKIE_LEN < TCP_FASTOPEN_PSK_LEN
 203 #error TCP_FASTOPEN_MAX_COOKIE_LEN must be >= TCP_FASTOPEN_PSK_LEN
 204 #endif
 205
 206 #define TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT        16
 207 #define TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT             2048 /* must be power of 2 */
 208
 209 #define TCP_FASTOPEN_PATH_DISABLE_TIME_DEFAULT          900 /* seconds */
 210
 211 #if !defined(TCP_RFC7413_MAX_KEYS) || (TCP_RFC7413_MAX_KEYS < 1)
 212 #define TCP_FASTOPEN_MAX_KEYS   2
 213 #else
 214 #define TCP_FASTOPEN_MAX_KEYS   TCP_RFC7413_MAX_KEYS
 215 #endif
 216
 217 #if TCP_FASTOPEN_MAX_KEYS > 10
 218 #undef TCP_FASTOPEN_MAX_KEYS
 219 #define TCP_FASTOPEN_MAX_KEYS   10
 220 #endif
 221
 222 #if !defined(TCP_RFC7413_MAX_PSKS) || (TCP_RFC7413_MAX_PSKS < 1)
 223 #define TCP_FASTOPEN_MAX_PSKS   2
 224 #else
 225 #define TCP_FASTOPEN_MAX_PSKS   TCP_RFC7413_MAX_PSKS
 226 #endif
 227
 228 #if TCP_FASTOPEN_MAX_PSKS > 10
 229 #undef TCP_FASTOPEN_MAX_PSKS
 230 #define TCP_FASTOPEN_MAX_PSKS   10
 231 #endif
 232
 233 struct tcp_fastopen_keylist {
 234         unsigned int newest;
 235         unsigned int newest_psk;
 236         uint8_t key[TCP_FASTOPEN_MAX_KEYS][TCP_FASTOPEN_KEY_LEN];
 237         uint8_t psk[TCP_FASTOPEN_MAX_PSKS][TCP_FASTOPEN_KEY_LEN];
 238 };
 239
 240 struct tcp_fastopen_callout {
 241         struct callout c;
 242         struct vnet *v;
 243 };
 244
 245 static struct tcp_fastopen_ccache_entry *tcp_fastopen_ccache_lookup(
 246     struct in_conninfo *, struct tcp_fastopen_ccache_bucket **);
 247 static struct tcp_fastopen_ccache_entry *tcp_fastopen_ccache_create(
 248     struct tcp_fastopen_ccache_bucket *, struct in_conninfo *, uint16_t, uint8_t,
 249     uint8_t *);
 250 static void tcp_fastopen_ccache_bucket_trim(struct tcp_fastopen_ccache_bucket *,
 251     unsigned int);
 252 static void tcp_fastopen_ccache_entry_drop(struct tcp_fastopen_ccache_entry *,
 253     struct tcp_fastopen_ccache_bucket *);
 254
 255 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, fastopen, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 256     "TCP Fast Open");
 257
 258 VNET_DEFINE_STATIC(int, tcp_fastopen_acceptany) = 0;
 259 #define V_tcp_fastopen_acceptany        VNET(tcp_fastopen_acceptany)
 260 SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, acceptany,
 261     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_fastopen_acceptany), 0,
 262     "Accept any non-empty cookie");
 263
 264 VNET_DEFINE_STATIC(unsigned int, tcp_fastopen_autokey) = 120;
 265 #define V_tcp_fastopen_autokey  VNET(tcp_fastopen_autokey)
 266 static int sysctl_net_inet_tcp_fastopen_autokey(SYSCTL_HANDLER_ARGS);
 267 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, autokey,
 268     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 269     NULL, 0, &sysctl_net_inet_tcp_fastopen_autokey, "IU",
 270     "Number of seconds between auto-generation of a new key; zero disables");
 271
 272 static int sysctl_net_inet_tcp_fastopen_ccache_bucket_limit(SYSCTL_HANDLER_ARGS);
 273 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, ccache_bucket_limit,
 274     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT,
 275     NULL, 0, &sysctl_net_inet_tcp_fastopen_ccache_bucket_limit, "IU",
 276     "Max entries per bucket in client cookie cache");
 277
 278 VNET_DEFINE_STATIC(unsigned int, tcp_fastopen_ccache_buckets) =
 279     TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT;
 280 #define V_tcp_fastopen_ccache_buckets VNET(tcp_fastopen_ccache_buckets)
 281 SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, ccache_buckets,
 282     CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_fastopen_ccache_buckets), 0,
 283     "Client cookie cache number of buckets (power of 2)");
 284
 285 VNET_DEFINE(unsigned int, tcp_fastopen_client_enable) = 1;
 286 static int sysctl_net_inet_tcp_fastopen_client_enable(SYSCTL_HANDLER_ARGS);
 287 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, client_enable,
 288     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
 289     NULL, 0, &sysctl_net_inet_tcp_fastopen_client_enable, "IU",
 290     "Enable/disable TCP Fast Open client functionality");
 291
 292 SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, keylen,
 293     CTLFLAG_RD, SYSCTL_NULL_INT_PTR, TCP_FASTOPEN_KEY_LEN,
 294     "Key length in bytes");
 295
 296 SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, maxkeys,
 297     CTLFLAG_RD, SYSCTL_NULL_INT_PTR, TCP_FASTOPEN_MAX_KEYS,
 298     "Maximum number of keys supported");
 299
 300 SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, maxpsks,
 301     CTLFLAG_RD, SYSCTL_NULL_INT_PTR, TCP_FASTOPEN_MAX_PSKS,
 302     "Maximum number of pre-shared keys supported");
 303
 304 VNET_DEFINE_STATIC(unsigned int, tcp_fastopen_numkeys) = 0;
 305 #define V_tcp_fastopen_numkeys  VNET(tcp_fastopen_numkeys)
 306 SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, numkeys,
 307     CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(tcp_fastopen_numkeys), 0,
 308     "Number of keys installed");
 309
 310 VNET_DEFINE_STATIC(unsigned int, tcp_fastopen_numpsks) = 0;
 311 #define V_tcp_fastopen_numpsks  VNET(tcp_fastopen_numpsks)
 312 SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, numpsks,
 313     CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(tcp_fastopen_numpsks), 0,
 314     "Number of pre-shared keys installed");
 315
 316 VNET_DEFINE_STATIC(unsigned int, tcp_fastopen_path_disable_time) =
 317     TCP_FASTOPEN_PATH_DISABLE_TIME_DEFAULT;
 318 #define V_tcp_fastopen_path_disable_time VNET(tcp_fastopen_path_disable_time)
 319 SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, path_disable_time,
 320     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_fastopen_path_disable_time), 0,
 321     "Seconds a TFO failure disables a {client_ip, server_ip, server_port} path");
 322
 323 VNET_DEFINE_STATIC(unsigned int, tcp_fastopen_psk_enable) = 0;
 324 #define V_tcp_fastopen_psk_enable       VNET(tcp_fastopen_psk_enable)
 325 static int sysctl_net_inet_tcp_fastopen_psk_enable(SYSCTL_HANDLER_ARGS);
 326 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, psk_enable,
 327     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 328     NULL, 0, &sysctl_net_inet_tcp_fastopen_psk_enable, "IU",
 329     "Enable/disable TCP Fast Open server pre-shared key mode");
 330
 331 VNET_DEFINE(unsigned int, tcp_fastopen_server_enable) = 0;
 332 static int sysctl_net_inet_tcp_fastopen_server_enable(SYSCTL_HANDLER_ARGS);
 333 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, server_enable,
 334     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 335     NULL, 0, &sysctl_net_inet_tcp_fastopen_server_enable, "IU",
 336     "Enable/disable TCP Fast Open server functionality");
 337
 338 static int sysctl_net_inet_tcp_fastopen_setkey(SYSCTL_HANDLER_ARGS);
 339 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, setkey,
 340     CTLFLAG_VNET | CTLTYPE_OPAQUE | CTLFLAG_WR | CTLFLAG_MPSAFE,
 341     NULL, 0, &sysctl_net_inet_tcp_fastopen_setkey, "",
 342     "Install a new key");
 343
 344 static int sysctl_net_inet_tcp_fastopen_setpsk(SYSCTL_HANDLER_ARGS);
 345 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, setpsk,
 346     CTLFLAG_VNET | CTLTYPE_OPAQUE | CTLFLAG_WR | CTLFLAG_MPSAFE,
 347     NULL, 0, &sysctl_net_inet_tcp_fastopen_setpsk, "",
 348     "Install a new pre-shared key");
 349
 350 static int sysctl_net_inet_tcp_fastopen_ccache_list(SYSCTL_HANDLER_ARGS);
 351 SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, ccache_list,
 352     CTLFLAG_VNET | CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
 353     NULL, 0, sysctl_net_inet_tcp_fastopen_ccache_list, "A",
 354     "List of all client cookie cache entries");
 355
 356 VNET_DEFINE_STATIC(struct rmlock, tcp_fastopen_keylock);
 357 #define V_tcp_fastopen_keylock  VNET(tcp_fastopen_keylock)
 358
 359 #define TCP_FASTOPEN_KEYS_RLOCK(t)      rm_rlock(&V_tcp_fastopen_keylock, (t))
 360 #define TCP_FASTOPEN_KEYS_RUNLOCK(t)    rm_runlock(&V_tcp_fastopen_keylock, (t))
 361 #define TCP_FASTOPEN_KEYS_WLOCK()       rm_wlock(&V_tcp_fastopen_keylock)
 362 #define TCP_FASTOPEN_KEYS_WUNLOCK()     rm_wunlock(&V_tcp_fastopen_keylock)
 363
 364 VNET_DEFINE_STATIC(struct tcp_fastopen_keylist, tcp_fastopen_keys);
 365 #define V_tcp_fastopen_keys     VNET(tcp_fastopen_keys)
 366
 367 VNET_DEFINE_STATIC(struct tcp_fastopen_callout, tcp_fastopen_autokey_ctx);
 368 #define V_tcp_fastopen_autokey_ctx      VNET(tcp_fastopen_autokey_ctx)
 369
 370 VNET_DEFINE_STATIC(uma_zone_t, counter_zone);
 371 #define V_counter_zone                  VNET(counter_zone)
 372
 373 static MALLOC_DEFINE(M_TCP_FASTOPEN_CCACHE, "tfo_ccache", "TFO client cookie cache buckets");
 374
 375 VNET_DEFINE_STATIC(struct tcp_fastopen_ccache, tcp_fastopen_ccache);
 376 #define V_tcp_fastopen_ccache   VNET(tcp_fastopen_ccache)
 377
 378 #define CCB_LOCK(ccb)           mtx_lock(&(ccb)->ccb_mtx)
 379 #define CCB_UNLOCK(ccb)         mtx_unlock(&(ccb)->ccb_mtx)
 380 #define CCB_LOCK_ASSERT(ccb)    mtx_assert(&(ccb)->ccb_mtx, MA_OWNED)
 381
 382 void
 383 tcp_fastopen_init(void)
 384 {
 385         unsigned int i;
 386
 387         V_counter_zone = uma_zcreate("tfo", sizeof(unsigned int),
 388             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 389         rm_init(&V_tcp_fastopen_keylock, "tfo_keylock");
 390         callout_init_rm(&V_tcp_fastopen_autokey_ctx.c,
 391             &V_tcp_fastopen_keylock, 0);
 392         V_tcp_fastopen_autokey_ctx.v = curvnet;
 393         V_tcp_fastopen_keys.newest = TCP_FASTOPEN_MAX_KEYS - 1;
 394         V_tcp_fastopen_keys.newest_psk = TCP_FASTOPEN_MAX_PSKS - 1;
 395
 396         /* May already be non-zero if kernel tunable was set */
 397         if (V_tcp_fastopen_ccache.bucket_limit == 0)
 398                 V_tcp_fastopen_ccache.bucket_limit =
 399                     TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT;
 400
 401         /* May already be non-zero if kernel tunable was set */
 402         if ((V_tcp_fastopen_ccache_buckets == 0) ||
 403             !powerof2(V_tcp_fastopen_ccache_buckets))
 404                 V_tcp_fastopen_ccache.buckets =
 405                         TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT;
 406         else
 407                 V_tcp_fastopen_ccache.buckets = V_tcp_fastopen_ccache_buckets;
 408
 409         V_tcp_fastopen_ccache.mask = V_tcp_fastopen_ccache.buckets - 1;
 410         V_tcp_fastopen_ccache.secret = arc4random();
 411
 412         V_tcp_fastopen_ccache.base = malloc(V_tcp_fastopen_ccache.buckets *
 413             sizeof(struct tcp_fastopen_ccache_bucket), M_TCP_FASTOPEN_CCACHE,
 414             M_WAITOK | M_ZERO);
 415
 416         for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
 417                 TAILQ_INIT(&V_tcp_fastopen_ccache.base[i].ccb_entries);
 418                 mtx_init(&V_tcp_fastopen_ccache.base[i].ccb_mtx, "tfo_ccache_bucket",
 419                          NULL, MTX_DEF);
 420                 if (V_tcp_fastopen_client_enable) {
 421                         /* enable bucket */
 422                         V_tcp_fastopen_ccache.base[i].ccb_num_entries = 0;
 423                 } else {
 424                         /* disable bucket */
 425                         V_tcp_fastopen_ccache.base[i].ccb_num_entries = -1;
 426                 }
 427                 V_tcp_fastopen_ccache.base[i].ccb_ccache = &V_tcp_fastopen_ccache;
 428         }
 429
 430         /*
 431          * Note that while the total number of entries in the cookie cache
 432          * is limited by the table management logic to
 433          * V_tcp_fastopen_ccache.buckets *
 434          * V_tcp_fastopen_ccache.bucket_limit, the total number of items in
 435          * this zone can exceed that amount by the number of CPUs in the
 436          * system times the maximum number of unallocated items that can be
 437          * present in each UMA per-CPU cache for this zone.
 438          */
 439         V_tcp_fastopen_ccache.zone = uma_zcreate("tfo_ccache_entries",
 440             sizeof(struct tcp_fastopen_ccache_entry), NULL, NULL, NULL, NULL,
 441             UMA_ALIGN_CACHE, 0);
 442 }
 443
 444 void
 445 tcp_fastopen_destroy(void)
 446 {
 447         struct tcp_fastopen_ccache_bucket *ccb;
 448         unsigned int i;
 449
 450         for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
 451                 ccb = &V_tcp_fastopen_ccache.base[i];
 452                 tcp_fastopen_ccache_bucket_trim(ccb, 0);
 453                 mtx_destroy(&ccb->ccb_mtx);
 454         }
 455
 456         KASSERT(uma_zone_get_cur(V_tcp_fastopen_ccache.zone) == 0,
 457             ("%s: TFO ccache zone allocation count not 0", __func__));
 458         uma_zdestroy(V_tcp_fastopen_ccache.zone);
 459         free(V_tcp_fastopen_ccache.base, M_TCP_FASTOPEN_CCACHE);
 460
 461         callout_drain(&V_tcp_fastopen_autokey_ctx.c);
 462         rm_destroy(&V_tcp_fastopen_keylock);
 463         uma_zdestroy(V_counter_zone);
 464 }
 465
 466 unsigned int *
 467 tcp_fastopen_alloc_counter(void)
 468 {
 469         unsigned int *counter;
 470         counter = uma_zalloc(V_counter_zone, M_NOWAIT);
 471         if (counter)
 472                 *counter = 1;
 473         return (counter);
 474 }
 475
 476 void
 477 tcp_fastopen_decrement_counter(unsigned int *counter)
 478 {
 479         if (*counter == 1)
 480                 uma_zfree(V_counter_zone, counter);
 481         else
 482                 atomic_subtract_int(counter, 1);
 483 }
 484
 485 static void
 486 tcp_fastopen_addkey_locked(uint8_t *key)
 487 {
 488
 489         V_tcp_fastopen_keys.newest++;
 490         if (V_tcp_fastopen_keys.newest == TCP_FASTOPEN_MAX_KEYS)
 491                 V_tcp_fastopen_keys.newest = 0;
 492         memcpy(V_tcp_fastopen_keys.key[V_tcp_fastopen_keys.newest], key,
 493             TCP_FASTOPEN_KEY_LEN);
 494         if (V_tcp_fastopen_numkeys < TCP_FASTOPEN_MAX_KEYS)
 495                 V_tcp_fastopen_numkeys++;
 496 }
 497
 498 static void
 499 tcp_fastopen_addpsk_locked(uint8_t *psk)
 500 {
 501
 502         V_tcp_fastopen_keys.newest_psk++;
 503         if (V_tcp_fastopen_keys.newest_psk == TCP_FASTOPEN_MAX_PSKS)
 504                 V_tcp_fastopen_keys.newest_psk = 0;
 505         memcpy(V_tcp_fastopen_keys.psk[V_tcp_fastopen_keys.newest_psk], psk,
 506             TCP_FASTOPEN_KEY_LEN);
 507         if (V_tcp_fastopen_numpsks < TCP_FASTOPEN_MAX_PSKS)
 508                 V_tcp_fastopen_numpsks++;
 509 }
 510
 511 static void
 512 tcp_fastopen_autokey_locked(void)
 513 {
 514         uint8_t newkey[TCP_FASTOPEN_KEY_LEN];
 515
 516         arc4rand(newkey, TCP_FASTOPEN_KEY_LEN, 0);
 517         tcp_fastopen_addkey_locked(newkey);
 518 }
 519
 520 static void
 521 tcp_fastopen_autokey_callout(void *arg)
 522 {
 523         struct tcp_fastopen_callout *ctx = arg;
 524
 525         CURVNET_SET(ctx->v);
 526         tcp_fastopen_autokey_locked();
 527         callout_reset(&ctx->c, V_tcp_fastopen_autokey * hz,
 528                       tcp_fastopen_autokey_callout, ctx);
 529         CURVNET_RESTORE();
 530 }
 531
 532 static uint64_t
 533 tcp_fastopen_make_cookie(uint8_t key[SIPHASH_KEY_LENGTH], struct in_conninfo *inc)
 534 {
 535         SIPHASH_CTX ctx;
 536         uint64_t siphash;
 537
 538         SipHash24_Init(&ctx);
 539         SipHash_SetKey(&ctx, key);
 540         switch (inc->inc_flags & INC_ISIPV6) {
 541 #ifdef INET
 542         case 0:
 543                 SipHash_Update(&ctx, &inc->inc_faddr, sizeof(inc->inc_faddr));
 544                 break;
 545 #endif
 546 #ifdef INET6
 547         case INC_ISIPV6:
 548                 SipHash_Update(&ctx, &inc->inc6_faddr, sizeof(inc->inc6_faddr));
 549                 break;
 550 #endif
 551         }
 552         SipHash_Final((u_int8_t *)&siphash, &ctx);
 553
 554         return (siphash);
 555 }
 556
 557 static uint64_t
 558 tcp_fastopen_make_psk_cookie(uint8_t *psk, uint8_t *cookie, uint8_t cookie_len)
 559 {
 560         SIPHASH_CTX ctx;
 561         uint64_t psk_cookie;
 562
 563         SipHash24_Init(&ctx);
 564         SipHash_SetKey(&ctx, psk);
 565         SipHash_Update(&ctx, cookie, cookie_len);
 566         SipHash_Final((u_int8_t *)&psk_cookie, &ctx);
 567
 568         return (psk_cookie);
 569 }
 570
 571 static int
 572 tcp_fastopen_find_cookie_match_locked(uint8_t *wire_cookie, uint64_t *cur_cookie)
 573 {
 574         unsigned int i, psk_index;
 575         uint64_t psk_cookie;
 576
 577         if (V_tcp_fastopen_psk_enable) {
 578                 psk_index = V_tcp_fastopen_keys.newest_psk;
 579                 for (i = 0; i < V_tcp_fastopen_numpsks; i++) {
 580                         psk_cookie =
 581                             tcp_fastopen_make_psk_cookie(
 582                                  V_tcp_fastopen_keys.psk[psk_index],
 583                                  (uint8_t *)cur_cookie,
 584                                  TCP_FASTOPEN_COOKIE_LEN);
 585
 586                         if (memcmp(wire_cookie, &psk_cookie,
 587                                    TCP_FASTOPEN_COOKIE_LEN) == 0)
 588                                 return (1);
 589
 590                         if (psk_index == 0)
 591                                 psk_index = TCP_FASTOPEN_MAX_PSKS - 1;
 592                         else
 593                                 psk_index--;
 594                 }
 595         } else if (memcmp(wire_cookie, cur_cookie, TCP_FASTOPEN_COOKIE_LEN) == 0)
 596                 return (1);
 597
 598         return (0);
 599 }
 600
 601 /*
 602  * Return values:
 603  *      -1      the cookie is invalid and no valid cookie is available
 604  *       0      the cookie is invalid and the latest cookie has been returned
 605  *       1      the cookie is valid and the latest cookie has been returned
 606  */
 607 int
 608 tcp_fastopen_check_cookie(struct in_conninfo *inc, uint8_t *cookie,
 609     unsigned int len, uint64_t *latest_cookie)
 610 {
 611         struct rm_priotracker tracker;
 612         unsigned int i, key_index;
 613         int rv;
 614         uint64_t cur_cookie;
 615
 616         if (V_tcp_fastopen_acceptany) {
 617                 *latest_cookie = 0;
 618                 return (1);
 619         }
 620
 621         TCP_FASTOPEN_KEYS_RLOCK(&tracker);
 622         if (len != TCP_FASTOPEN_COOKIE_LEN) {
 623                 if (V_tcp_fastopen_numkeys > 0) {
 624                         *latest_cookie =
 625                             tcp_fastopen_make_cookie(
 626                                 V_tcp_fastopen_keys.key[V_tcp_fastopen_keys.newest],
 627                                 inc);
 628                         rv = 0;
 629                 } else
 630                         rv = -1;
 631                 goto out;
 632         }
 633
 634         /*
 635          * Check against each available key, from newest to oldest.
 636          */
 637         key_index = V_tcp_fastopen_keys.newest;
 638         for (i = 0; i < V_tcp_fastopen_numkeys; i++) {
 639                 cur_cookie =
 640                     tcp_fastopen_make_cookie(V_tcp_fastopen_keys.key[key_index],
 641                         inc);
 642                 if (i == 0)
 643                         *latest_cookie = cur_cookie;
 644                 rv = tcp_fastopen_find_cookie_match_locked(cookie, &cur_cookie);
 645                 if (rv)
 646                         goto out;
 647                 if (key_index == 0)
 648                         key_index = TCP_FASTOPEN_MAX_KEYS - 1;
 649                 else
 650                         key_index--;
 651         }
 652         rv = 0;
 653
 654  out:
 655         TCP_FASTOPEN_KEYS_RUNLOCK(&tracker);
 656         return (rv);
 657 }
 658
 659 static int
 660 sysctl_net_inet_tcp_fastopen_autokey(SYSCTL_HANDLER_ARGS)
 661 {
 662         int error;
 663         unsigned int new;
 664
 665         new = V_tcp_fastopen_autokey;
 666         error = sysctl_handle_int(oidp, &new, 0, req);
 667         if (error == 0 && req->newptr) {
 668                 if (new > (INT_MAX / hz))
 669                         return (EINVAL);
 670
 671                 TCP_FASTOPEN_KEYS_WLOCK();
 672                 if (V_tcp_fastopen_server_enable) {
 673                         if (V_tcp_fastopen_autokey && !new)
 674                                 callout_stop(&V_tcp_fastopen_autokey_ctx.c);
 675                         else if (new)
 676                                 callout_reset(&V_tcp_fastopen_autokey_ctx.c,
 677                                     new * hz, tcp_fastopen_autokey_callout,
 678                                     &V_tcp_fastopen_autokey_ctx);
 679                 }
 680                 V_tcp_fastopen_autokey = new;
 681                 TCP_FASTOPEN_KEYS_WUNLOCK();
 682         }
 683
 684         return (error);
 685 }
 686
 687 static int
 688 sysctl_net_inet_tcp_fastopen_psk_enable(SYSCTL_HANDLER_ARGS)
 689 {
 690         int error;
 691         unsigned int new;
 692
 693         new = V_tcp_fastopen_psk_enable;
 694         error = sysctl_handle_int(oidp, &new, 0, req);
 695         if (error == 0 && req->newptr) {
 696                 if (V_tcp_fastopen_psk_enable && !new) {
 697                         /* enabled -> disabled */
 698                         TCP_FASTOPEN_KEYS_WLOCK();
 699                         V_tcp_fastopen_numpsks = 0;
 700                         V_tcp_fastopen_keys.newest_psk =
 701                             TCP_FASTOPEN_MAX_PSKS - 1;
 702                         V_tcp_fastopen_psk_enable = 0;
 703                         TCP_FASTOPEN_KEYS_WUNLOCK();
 704                 } else if (!V_tcp_fastopen_psk_enable && new) {
 705                         /* disabled -> enabled */
 706                         TCP_FASTOPEN_KEYS_WLOCK();
 707                         V_tcp_fastopen_psk_enable = 1;
 708                         TCP_FASTOPEN_KEYS_WUNLOCK();
 709                 }
 710         }
 711         return (error);
 712 }
 713
 714 static int
 715 sysctl_net_inet_tcp_fastopen_server_enable(SYSCTL_HANDLER_ARGS)
 716 {
 717         int error;
 718         unsigned int new;
 719
 720         new = V_tcp_fastopen_server_enable;
 721         error = sysctl_handle_int(oidp, &new, 0, req);
 722         if (error == 0 && req->newptr) {
 723                 if (V_tcp_fastopen_server_enable && !new) {
 724                         /* enabled -> disabled */
 725                         TCP_FASTOPEN_KEYS_WLOCK();
 726                         V_tcp_fastopen_numkeys = 0;
 727                         V_tcp_fastopen_keys.newest = TCP_FASTOPEN_MAX_KEYS - 1;
 728                         if (V_tcp_fastopen_autokey)
 729                                 callout_stop(&V_tcp_fastopen_autokey_ctx.c);
 730                         V_tcp_fastopen_numpsks = 0;
 731                         V_tcp_fastopen_keys.newest_psk =
 732                             TCP_FASTOPEN_MAX_PSKS - 1;
 733                         V_tcp_fastopen_server_enable = 0;
 734                         TCP_FASTOPEN_KEYS_WUNLOCK();
 735                 } else if (!V_tcp_fastopen_server_enable && new) {
 736                         /* disabled -> enabled */
 737                         TCP_FASTOPEN_KEYS_WLOCK();
 738                         if (V_tcp_fastopen_autokey &&
 739                             (V_tcp_fastopen_numkeys == 0)) {
 740                                 tcp_fastopen_autokey_locked();
 741                                 callout_reset(&V_tcp_fastopen_autokey_ctx.c,
 742                                     V_tcp_fastopen_autokey * hz,
 743                                     tcp_fastopen_autokey_callout,
 744                                     &V_tcp_fastopen_autokey_ctx);
 745                         }
 746                         V_tcp_fastopen_server_enable = 1;
 747                         TCP_FASTOPEN_KEYS_WUNLOCK();
 748                 }
 749         }
 750         return (error);
 751 }
 752
 753 static int
 754 sysctl_net_inet_tcp_fastopen_setkey(SYSCTL_HANDLER_ARGS)
 755 {
 756         int error;
 757         uint8_t newkey[TCP_FASTOPEN_KEY_LEN];
 758
 759         if (req->oldptr != NULL || req->oldlen != 0)
 760                 return (EINVAL);
 761         if (req->newptr == NULL)
 762                 return (EPERM);
 763         if (req->newlen != sizeof(newkey))
 764                 return (EINVAL);
 765         error = SYSCTL_IN(req, newkey, sizeof(newkey));
 766         if (error)
 767                 return (error);
 768
 769         TCP_FASTOPEN_KEYS_WLOCK();
 770         tcp_fastopen_addkey_locked(newkey);
 771         TCP_FASTOPEN_KEYS_WUNLOCK();
 772
 773         return (0);
 774 }
 775
 776 static int
 777 sysctl_net_inet_tcp_fastopen_setpsk(SYSCTL_HANDLER_ARGS)
 778 {
 779         int error;
 780         uint8_t newpsk[TCP_FASTOPEN_KEY_LEN];
 781
 782         if (req->oldptr != NULL || req->oldlen != 0)
 783                 return (EINVAL);
 784         if (req->newptr == NULL)
 785                 return (EPERM);
 786         if (req->newlen != sizeof(newpsk))
 787                 return (EINVAL);
 788         error = SYSCTL_IN(req, newpsk, sizeof(newpsk));
 789         if (error)
 790                 return (error);
 791
 792         TCP_FASTOPEN_KEYS_WLOCK();
 793         tcp_fastopen_addpsk_locked(newpsk);
 794         TCP_FASTOPEN_KEYS_WUNLOCK();
 795
 796         return (0);
 797 }
 798
 799 static int
 800 sysctl_net_inet_tcp_fastopen_ccache_bucket_limit(SYSCTL_HANDLER_ARGS)
 801 {
 802         struct tcp_fastopen_ccache_bucket *ccb;
 803         int error;
 804         unsigned int new;
 805         unsigned int i;
 806
 807         new = V_tcp_fastopen_ccache.bucket_limit;
 808         error = sysctl_handle_int(oidp, &new, 0, req);
 809         if (error == 0 && req->newptr) {
 810                 if ((new == 0) || (new > INT_MAX))
 811                         error = EINVAL;
 812                 else {
 813                         if (new < V_tcp_fastopen_ccache.bucket_limit) {
 814                                 for (i = 0; i < V_tcp_fastopen_ccache.buckets;
 815                                      i++) {
 816                                         ccb = &V_tcp_fastopen_ccache.base[i];
 817                                         tcp_fastopen_ccache_bucket_trim(ccb, new);
 818                                 }
 819                         }
 820                         V_tcp_fastopen_ccache.bucket_limit = new;
 821                 }
 822         }
 823         return (error);
 824 }
 825
 826 static int
 827 sysctl_net_inet_tcp_fastopen_client_enable(SYSCTL_HANDLER_ARGS)
 828 {
 829         struct tcp_fastopen_ccache_bucket *ccb;
 830         int error;
 831         unsigned int new, i;
 832
 833         new = V_tcp_fastopen_client_enable;
 834         error = sysctl_handle_int(oidp, &new, 0, req);
 835         if (error == 0 && req->newptr) {
 836                 if (V_tcp_fastopen_client_enable && !new) {
 837                         /* enabled -> disabled */
 838                         for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
 839                                 ccb = &V_tcp_fastopen_ccache.base[i];
 840                                 KASSERT(ccb->ccb_num_entries > -1,
 841                                     ("%s: ccb->ccb_num_entries %d is negative",
 842                                         __func__, ccb->ccb_num_entries));
 843                                 tcp_fastopen_ccache_bucket_trim(ccb, 0);
 844                         }
 845                         V_tcp_fastopen_client_enable = 0;
 846                 } else if (!V_tcp_fastopen_client_enable && new) {
 847                         /* disabled -> enabled */
 848                         for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
 849                                 ccb = &V_tcp_fastopen_ccache.base[i];
 850                                 CCB_LOCK(ccb);
 851                                 KASSERT(TAILQ_EMPTY(&ccb->ccb_entries),
 852                                     ("%s: ccb->ccb_entries not empty", __func__));
 853                                 KASSERT(ccb->ccb_num_entries == -1,
 854                                     ("%s: ccb->ccb_num_entries %d not -1", __func__,
 855                                         ccb->ccb_num_entries));
 856                                 ccb->ccb_num_entries = 0; /* enable bucket */
 857                                 CCB_UNLOCK(ccb);
 858                         }
 859                         V_tcp_fastopen_client_enable = 1;
 860                 }
 861         }
 862         return (error);
 863 }
 864
 865 void
 866 tcp_fastopen_connect(struct tcpcb *tp)
 867 {
 868         struct inpcb *inp = tptoinpcb(tp);
 869         struct tcp_fastopen_ccache_bucket *ccb;
 870         struct tcp_fastopen_ccache_entry *cce;
 871         sbintime_t now;
 872         uint16_t server_mss;
 873         uint64_t psk_cookie;
 874
 875         psk_cookie = 0;
 876         cce = tcp_fastopen_ccache_lookup(&inp->inp_inc, &ccb);
 877         if (cce) {
 878                 if (cce->disable_time == 0) {
 879                         if ((cce->cookie_len > 0) &&
 880                             (tp->t_tfo_client_cookie_len ==
 881                              TCP_FASTOPEN_PSK_LEN)) {
 882                                 psk_cookie =
 883                                     tcp_fastopen_make_psk_cookie(
 884                                         tp->t_tfo_cookie.client,
 885                                         cce->cookie, cce->cookie_len);
 886                         } else {
 887                                 tp->t_tfo_client_cookie_len = cce->cookie_len;
 888                                 memcpy(tp->t_tfo_cookie.client, cce->cookie,
 889                                     cce->cookie_len);
 890                         }
 891                         server_mss = cce->server_mss;
 892                         CCB_UNLOCK(ccb);
 893                         if (tp->t_tfo_client_cookie_len ==
 894                             TCP_FASTOPEN_PSK_LEN && psk_cookie) {
 895                                 tp->t_tfo_client_cookie_len =
 896                                     TCP_FASTOPEN_COOKIE_LEN;
 897                                 memcpy(tp->t_tfo_cookie.client, &psk_cookie,
 898                                     TCP_FASTOPEN_COOKIE_LEN);
 899                         }
 900                         tcp_mss(tp, server_mss ? server_mss : -1);
 901                         tp->snd_wnd = tp->t_maxseg;
 902                 } else {
 903                         /*
 904                          * The path is disabled.  Check the time and
 905                          * possibly re-enable.
 906                          */
 907                         now = getsbinuptime();
 908                         if (now - cce->disable_time >
 909                             ((sbintime_t)V_tcp_fastopen_path_disable_time << 32)) {
 910                                 /*
 911                                  * Re-enable path.  Force a TFO cookie
 912                                  * request.  Forget the old MSS as it may be
 913                                  * bogus now, and we will rediscover it in
 914                                  * the SYN|ACK.
 915                                  */
 916                                 cce->disable_time = 0;
 917                                 cce->server_mss = 0;
 918                                 cce->cookie_len = 0;
 919                                 /*
 920                                  * tp->t_tfo... cookie details are already
 921                                  * zero from the tcpcb init.
 922                                  */
 923                         } else {
 924                                 /*
 925                                  * Path is disabled, so disable TFO on this
 926                                  * connection.
 927                                  */
 928                                 tp->t_flags &= ~TF_FASTOPEN;
 929                         }
 930                         CCB_UNLOCK(ccb);
 931                         tcp_mss(tp, -1);
 932                         /*
 933                          * snd_wnd is irrelevant since we are either forcing
 934                          * a TFO cookie request or disabling TFO - either
 935                          * way, no data with the SYN.
 936                          */
 937                 }
 938         } else {
 939                 /*
 940                  * A new entry for this path will be created when a SYN|ACK
 941                  * comes back, or the attempt otherwise fails.
 942                  */
 943                 CCB_UNLOCK(ccb);
 944                 tcp_mss(tp, -1);
 945                 /*
 946                  * snd_wnd is irrelevant since we are forcing a TFO cookie
 947                  * request.
 948                  */
 949         }
 950 }
 951
 952 void
 953 tcp_fastopen_disable_path(struct tcpcb *tp)
 954 {
 955         struct in_conninfo *inc = &tptoinpcb(tp)->inp_inc;
 956         struct tcp_fastopen_ccache_bucket *ccb;
 957         struct tcp_fastopen_ccache_entry *cce;
 958
 959         cce = tcp_fastopen_ccache_lookup(inc, &ccb);
 960         if (cce) {
 961                 cce->server_mss = 0;
 962                 cce->cookie_len = 0;
 963                 /*
 964                  * Preserve the existing disable time if it is already
 965                  * disabled.
 966                  */
 967                 if (cce->disable_time == 0)
 968                         cce->disable_time = getsbinuptime();
 969         } else /* use invalid cookie len to create disabled entry */
 970                 tcp_fastopen_ccache_create(ccb, inc, 0,
 971                     TCP_FASTOPEN_MAX_COOKIE_LEN + 1, NULL);
 972
 973         CCB_UNLOCK(ccb);
 974         tp->t_flags &= ~TF_FASTOPEN;
 975 }
 976
 977 void
 978 tcp_fastopen_update_cache(struct tcpcb *tp, uint16_t mss,
 979     uint8_t cookie_len, uint8_t *cookie)
 980 {
 981         struct in_conninfo *inc = &tptoinpcb(tp)->inp_inc;
 982         struct tcp_fastopen_ccache_bucket *ccb;
 983         struct tcp_fastopen_ccache_entry *cce;
 984
 985         cce = tcp_fastopen_ccache_lookup(inc, &ccb);
 986         if (cce) {
 987                 if ((cookie_len >= TCP_FASTOPEN_MIN_COOKIE_LEN) &&
 988                     (cookie_len <= TCP_FASTOPEN_MAX_COOKIE_LEN) &&
 989                     ((cookie_len & 0x1) == 0)) {
 990                         cce->server_mss = mss;
 991                         cce->cookie_len = cookie_len;
 992                         memcpy(cce->cookie, cookie, cookie_len);
 993                         cce->disable_time = 0;
 994                 } else {
 995                         /* invalid cookie length, disable entry */
 996                         cce->server_mss = 0;
 997                         cce->cookie_len = 0;
 998                         /*
 999                          * Preserve the existing disable time if it is
1000                          * already disabled.
1001                          */
1002                         if (cce->disable_time == 0)
1003                                 cce->disable_time = getsbinuptime();
1004                 }
1005         } else
1006                 tcp_fastopen_ccache_create(ccb, inc, mss, cookie_len, cookie);
1007
1008         CCB_UNLOCK(ccb);
1009 }
1010
1011 static struct tcp_fastopen_ccache_entry *
1012 tcp_fastopen_ccache_lookup(struct in_conninfo *inc,
1013     struct tcp_fastopen_ccache_bucket **ccbp)
1014 {
1015         struct tcp_fastopen_ccache_bucket *ccb;
1016         struct tcp_fastopen_ccache_entry *cce;
1017         uint32_t last_word;
1018         uint32_t hash;
1019
1020         hash = jenkins_hash32((uint32_t *)&inc->inc_ie.ie_dependladdr, 4,
1021             V_tcp_fastopen_ccache.secret);
1022         hash = jenkins_hash32((uint32_t *)&inc->inc_ie.ie_dependfaddr, 4,
1023             hash);
1024         last_word = inc->inc_fport;
1025         hash = jenkins_hash32(&last_word, 1, hash);
1026         ccb = &V_tcp_fastopen_ccache.base[hash & V_tcp_fastopen_ccache.mask];
1027         *ccbp = ccb;
1028         CCB_LOCK(ccb);
1029
1030         /*
1031          * Always returns with locked bucket.
1032          */
1033         TAILQ_FOREACH(cce, &ccb->ccb_entries, cce_link)
1034                 if ((!(cce->af == AF_INET6) == !(inc->inc_flags & INC_ISIPV6)) &&
1035                     (cce->server_port == inc->inc_ie.ie_fport) &&
1036                     (((cce->af == AF_INET) &&
1037                       (cce->cce_client_ip.v4.s_addr == inc->inc_laddr.s_addr) &&
1038                       (cce->cce_server_ip.v4.s_addr == inc->inc_faddr.s_addr)) ||
1039                      ((cce->af == AF_INET6) &&
1040                       IN6_ARE_ADDR_EQUAL(&cce->cce_client_ip.v6, &inc->inc6_laddr) &&
1041                       IN6_ARE_ADDR_EQUAL(&cce->cce_server_ip.v6, &inc->inc6_faddr))))
1042                         break;
1043
1044         return (cce);
1045 }
1046
1047 static struct tcp_fastopen_ccache_entry *
1048 tcp_fastopen_ccache_create(struct tcp_fastopen_ccache_bucket *ccb,
1049     struct in_conninfo *inc, uint16_t mss, uint8_t cookie_len, uint8_t *cookie)
1050 {
1051         struct tcp_fastopen_ccache_entry *cce;
1052
1053         /*
1054          * 1. Create a new entry, or
1055          * 2. Reclaim an existing entry, or
1056          * 3. Fail
1057          */
1058
1059         CCB_LOCK_ASSERT(ccb);
1060
1061         cce = NULL;
1062         if (ccb->ccb_num_entries < V_tcp_fastopen_ccache.bucket_limit)
1063                 cce = uma_zalloc(V_tcp_fastopen_ccache.zone, M_NOWAIT);
1064
1065         if (cce == NULL) {
1066                 /*
1067                  * At bucket limit, or out of memory - reclaim last
1068                  * entry in bucket.
1069                  */
1070                 cce = TAILQ_LAST(&ccb->ccb_entries, bucket_entries);
1071                 if (cce == NULL) {
1072                         /* XXX count this event */
1073                         return (NULL);
1074                 }
1075
1076                 TAILQ_REMOVE(&ccb->ccb_entries, cce, cce_link);
1077         } else
1078                 ccb->ccb_num_entries++;
1079
1080         TAILQ_INSERT_HEAD(&ccb->ccb_entries, cce, cce_link);
1081         cce->af = (inc->inc_flags & INC_ISIPV6) ? AF_INET6 : AF_INET;
1082         if (cce->af == AF_INET) {
1083                 cce->cce_client_ip.v4 = inc->inc_laddr;
1084                 cce->cce_server_ip.v4 = inc->inc_faddr;
1085         } else {
1086                 cce->cce_client_ip.v6 = inc->inc6_laddr;
1087                 cce->cce_server_ip.v6 = inc->inc6_faddr;
1088         }
1089         cce->server_port = inc->inc_fport;
1090         if ((cookie_len >= TCP_FASTOPEN_MIN_COOKIE_LEN) &&
1091             (cookie_len <= TCP_FASTOPEN_MAX_COOKIE_LEN) &&
1092             ((cookie_len & 0x1) == 0)) {
1093                 cce->server_mss = mss;
1094                 cce->cookie_len = cookie_len;
1095                 memcpy(cce->cookie, cookie, cookie_len);
1096                 cce->disable_time = 0;
1097         } else {
1098                 /* invalid cookie length, disable cce */
1099                 cce->server_mss = 0;
1100                 cce->cookie_len = 0;
1101                 cce->disable_time = getsbinuptime();
1102         }
1103
1104         return (cce);
1105 }
1106
1107 static void
1108 tcp_fastopen_ccache_bucket_trim(struct tcp_fastopen_ccache_bucket *ccb,
1109     unsigned int limit)
1110 {
1111         struct tcp_fastopen_ccache_entry *cce, *cce_tmp;
1112         unsigned int entries;
1113
1114         CCB_LOCK(ccb);
1115         entries = 0;
1116         TAILQ_FOREACH_SAFE(cce, &ccb->ccb_entries, cce_link, cce_tmp) {
1117                 entries++;
1118                 if (entries > limit)
1119                         tcp_fastopen_ccache_entry_drop(cce, ccb);
1120         }
1121         KASSERT(ccb->ccb_num_entries <= (int)limit,
1122             ("%s: ccb->ccb_num_entries %d exceeds limit %d", __func__,
1123                 ccb->ccb_num_entries, limit));
1124         if (limit == 0) {
1125                 KASSERT(TAILQ_EMPTY(&ccb->ccb_entries),
1126                     ("%s: ccb->ccb_entries not empty", __func__));
1127                 ccb->ccb_num_entries = -1; /* disable bucket */
1128         }
1129         CCB_UNLOCK(ccb);
1130 }
1131
1132 static void
1133 tcp_fastopen_ccache_entry_drop(struct tcp_fastopen_ccache_entry *cce,
1134     struct tcp_fastopen_ccache_bucket *ccb)
1135 {
1136
1137         CCB_LOCK_ASSERT(ccb);
1138
1139         TAILQ_REMOVE(&ccb->ccb_entries, cce, cce_link);
1140         ccb->ccb_num_entries--;
1141         uma_zfree(V_tcp_fastopen_ccache.zone, cce);
1142 }
1143
1144 static int
1145 sysctl_net_inet_tcp_fastopen_ccache_list(SYSCTL_HANDLER_ARGS)
1146 {
1147         struct sbuf sb;
1148         struct tcp_fastopen_ccache_bucket *ccb;
1149         struct tcp_fastopen_ccache_entry *cce;
1150         sbintime_t now, duration, limit;
1151         const int linesize = 128;
1152         int i, error, num_entries;
1153         unsigned int j;
1154 #ifdef INET6
1155         char clt_buf[INET6_ADDRSTRLEN], srv_buf[INET6_ADDRSTRLEN];
1156 #else
1157         char clt_buf[INET_ADDRSTRLEN], srv_buf[INET_ADDRSTRLEN];
1158 #endif
1159
1160         if (jailed_without_vnet(curthread->td_ucred) != 0)
1161                 return (EPERM);
1162
1163         /* Only allow root to read the client cookie cache */
1164         if (curthread->td_ucred->cr_uid != 0)
1165                 return (EPERM);
1166
1167         num_entries = 0;
1168         for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
1169                 ccb = &V_tcp_fastopen_ccache.base[i];
1170                 CCB_LOCK(ccb);
1171                 if (ccb->ccb_num_entries > 0)
1172                         num_entries += ccb->ccb_num_entries;
1173                 CCB_UNLOCK(ccb);
1174         }
1175         sbuf_new(&sb, NULL, linesize * (num_entries + 1), SBUF_INCLUDENUL);
1176
1177         sbuf_printf(&sb,
1178                     "\nLocal IP address     Remote IP address     Port   MSS"
1179                     " Disabled Cookie\n");
1180
1181         now = getsbinuptime();
1182         limit = (sbintime_t)V_tcp_fastopen_path_disable_time << 32;
1183         for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
1184                 ccb = &V_tcp_fastopen_ccache.base[i];
1185                 CCB_LOCK(ccb);
1186                 TAILQ_FOREACH(cce, &ccb->ccb_entries, cce_link) {
1187                         if (cce->disable_time != 0) {
1188                                 duration = now - cce->disable_time;
1189                                 if (limit >= duration)
1190                                         duration = limit - duration;
1191                                 else
1192                                         duration = 0;
1193                         } else
1194                                 duration = 0;
1195                         sbuf_printf(&sb,
1196                                     "%-20s %-20s %5u %5u ",
1197                                     inet_ntop(cce->af, &cce->cce_client_ip,
1198                                         clt_buf, sizeof(clt_buf)),
1199                                     inet_ntop(cce->af, &cce->cce_server_ip,
1200                                         srv_buf, sizeof(srv_buf)),
1201                                     ntohs(cce->server_port),
1202                                     cce->server_mss);
1203                         if (duration > 0)
1204                                 sbuf_printf(&sb, "%7ds ", sbintime_getsec(duration));
1205                         else
1206                                 sbuf_printf(&sb, "%8s ", "No");
1207                         for (j = 0; j < cce->cookie_len; j++)
1208                                 sbuf_printf(&sb, "%02x", cce->cookie[j]);
1209                         sbuf_putc(&sb, '\n');
1210                 }
1211                 CCB_UNLOCK(ccb);
1212         }
1213         error = sbuf_finish(&sb);
1214         if (error == 0)
1215                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
1216         sbuf_delete(&sb);
1217         return (error);
1218 }