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freebsd-dev/sys/netinet/tcp_fastopen.c
Michael Tuexen 1c714531e8 When checking the TCP fast cookie length, conststently also check 
for the minimum length.

This fixes a bug where cookies of length 2 bytes (which is smaller
than the minimum length of 4) is provided by the server.

Sponsored by:	Netflix, Inc.
2018-02-27 22:12:38 +00:00

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/*-
* Copyright (c) 2015-2017 Patrick Kelsey
* All rights reserved.
*
* 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 is an implementation of TCP Fast Open (TFO) [RFC7413]. To include
* this code, add the following line to your kernel config:
*
* options TCP_RFC7413
*
*
* The generated TFO cookies are the 64-bit output of
* SipHash24(key=<16-byte-key>, msg=<client-ip>). Multiple concurrent valid
* keys are supported so that time-based rolling cookie invalidation
* policies can be implemented in the system. The default number of
* concurrent keys is 2. This can be adjusted in the kernel config as
* follows:
*
* options TCP_RFC7413_MAX_KEYS=<num-keys>
*
*
* In addition to the facilities defined in RFC7413, this implementation
* supports a pre-shared key (PSK) mode of operation in which the TFO server
* requires the client to be in posession of a shared secret in order for
* the client to be able to successfully open TFO connections with the
* server. This is useful, for example, in environments where TFO servers
* are exposed to both internal and external clients and only wish to allow
* TFO connections from internal clients.
*
* In the PSK mode of operation, the server generates and sends TFO cookies
* to requesting clients as usual. However, when validating cookies
* received in TFO SYNs from clients, the server requires the
* client-supplied cookie to equal SipHash24(key=<16-byte-psk>,
* msg=<cookie-sent-to-client>).
*
* Multiple concurrent valid pre-shared keys are supported so that
* time-based rolling PSK invalidation policies can be implemented in the
* system. The default number of concurrent pre-shared keys is 2. This can
* be adjusted in the kernel config as follows:
*
* options TCP_RFC7413_MAX_PSKS=<num-psks>
*
*
* The following TFO-specific sysctls are defined:
*
* net.inet.tcp.fastopen.acceptany (RW, default 0)
* When non-zero, all client-supplied TFO cookies will be considered to
* be valid.
*
* net.inet.tcp.fastopen.autokey (RW, default 120)
* When this and net.inet.tcp.fastopen.server_enable are non-zero, a new
* key will be automatically generated after this many seconds.
*
* net.inet.tcp.fastopen.ccache_bucket_limit
* (RWTUN, default TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT)
* The maximum number of entries in a client cookie cache bucket.
*
* net.inet.tcp.fastopen.ccache_buckets
* (RDTUN, default TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT)
* The number of client cookie cache buckets.
*
* net.inet.tcp.fastopen.client_enable (RW, default 0)
* When zero, no new active (i.e., client) TFO connections can be
* created. On the transition from enabled to disabled, the client
* cookie cache is cleared and disabled. The transition from enabled to
* disabled does not affect any active TFO connections in progress; it
* only prevents new ones from being made.
*
* net.inet.tcp.fastopen.keylen (RD)
* The key length in bytes.
*
* net.inet.tcp.fastopen.maxkeys (RD)
* The maximum number of keys supported.
*
* net.inet.tcp.fastopen.maxpsks (RD)
* The maximum number of pre-shared keys supported.
*
* net.inet.tcp.fastopen.numkeys (RD)
* The current number of keys installed.
*
* net.inet.tcp.fastopen.numpsks (RD)
* The current number of pre-shared keys installed.
*
* net.inet.tcp.fastopen.path_disable_time
* (RW, default TCP_FASTOPEN_PATH_DISABLE_TIME_DEFAULT)
* When a failure occurs while trying to create a new active (i.e.,
* client) TFO connection, new active connections on the same path, as
* determined by the tuple {client_ip, server_ip, server_port}, will be
* forced to be non-TFO for this many seconds. Note that the path
* disable mechanism relies on state stored in client cookie cache
* entries, so it is possible for the disable time for a given path to
* be reduced if the corresponding client cookie cache entry is reused
* due to resource pressure before the disable period has elapsed.
*
* net.inet.tcp.fastopen.psk_enable (RW, default 0)
* When non-zero, pre-shared key (PSK) mode is enabled for all TFO
* servers. On the transition from enabled to disabled, all installed
* pre-shared keys are removed.
*
* net.inet.tcp.fastopen.server_enable (RW, default 0)
* When zero, no new passive (i.e., server) TFO connections can be
* created. On the transition from enabled to disabled, all installed
* keys and pre-shared keys are removed. On the transition from
* disabled to enabled, if net.inet.tcp.fastopen.autokey is non-zero and
* there are no keys installed, a new key will be generated immediately.
* The transition from enabled to disabled does not affect any passive
* TFO connections in progress; it only prevents new ones from being
* made.
*
* net.inet.tcp.fastopen.setkey (WR)
* Install a new key by writing net.inet.tcp.fastopen.keylen bytes to
* this sysctl.
*
* net.inet.tcp.fastopen.setpsk (WR)
* Install a new pre-shared key by writing net.inet.tcp.fastopen.keylen
* bytes to this sysctl.
*
* In order for TFO connections to be created via a listen socket, that
* socket must have the TCP_FASTOPEN socket option set on it. This option
* can be set on the socket either before or after the listen() is invoked.
* Clearing this option on a listen socket after it has been set has no
* effect on existing TFO connections or TFO connections in progress; it
* only prevents new TFO connections from being made.
*
* For passively-created sockets, the TCP_FASTOPEN socket option can be
* queried to determine whether the connection was established using TFO.
* Note that connections that are established via a TFO SYN, but that fall
* back to using a non-TFO SYN|ACK will have the TCP_FASTOPEN socket option
* set.
*
* Per the RFC, this implementation limits the number of TFO connections
* that can be in the SYN_RECEIVED state on a per listen-socket basis.
* Whenever this limit is exceeded, requests for new TFO connections are
* serviced as non-TFO requests. Without such a limit, given a valid TFO
* cookie, an attacker could keep the listen queue in an overflow condition
* using a TFO SYN flood. This implementation sets the limit at half the
* configured listen backlog.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/hash.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <crypto/siphash/siphash.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_fastopen.h>
#define TCP_FASTOPEN_KEY_LEN SIPHASH_KEY_LENGTH
#if TCP_FASTOPEN_PSK_LEN != TCP_FASTOPEN_KEY_LEN
#error TCP_FASTOPEN_PSK_LEN must be equal to TCP_FASTOPEN_KEY_LEN
#endif
/*
* Because a PSK-mode setsockopt() uses tcpcb.t_tfo_cookie.client to hold
* the PSK until the connect occurs.
*/
#if TCP_FASTOPEN_MAX_COOKIE_LEN < TCP_FASTOPEN_PSK_LEN
#error TCP_FASTOPEN_MAX_COOKIE_LEN must be >= TCP_FASTOPEN_PSK_LEN
#endif
#define TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT 16
#define TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT 2048 /* must be power of 2 */
#define TCP_FASTOPEN_PATH_DISABLE_TIME_DEFAULT 900 /* seconds */
#if !defined(TCP_RFC7413_MAX_KEYS) || (TCP_RFC7413_MAX_KEYS < 1)
#define TCP_FASTOPEN_MAX_KEYS 2
#else
#define TCP_FASTOPEN_MAX_KEYS TCP_RFC7413_MAX_KEYS
#endif
#if TCP_FASTOPEN_MAX_KEYS > 10
#undef TCP_FASTOPEN_MAX_KEYS
#define TCP_FASTOPEN_MAX_KEYS 10
#endif
#if !defined(TCP_RFC7413_MAX_PSKS) || (TCP_RFC7413_MAX_PSKS < 1)
#define TCP_FASTOPEN_MAX_PSKS 2
#else
#define TCP_FASTOPEN_MAX_PSKS TCP_RFC7413_MAX_PSKS
#endif
#if TCP_FASTOPEN_MAX_PSKS > 10
#undef TCP_FASTOPEN_MAX_PSKS
#define TCP_FASTOPEN_MAX_PSKS 10
#endif
struct tcp_fastopen_keylist {
unsigned int newest;
unsigned int newest_psk;
uint8_t key[TCP_FASTOPEN_MAX_KEYS][TCP_FASTOPEN_KEY_LEN];
uint8_t psk[TCP_FASTOPEN_MAX_PSKS][TCP_FASTOPEN_KEY_LEN];
};
struct tcp_fastopen_callout {
struct callout c;
struct vnet *v;
};
static struct tcp_fastopen_ccache_entry *tcp_fastopen_ccache_lookup(
struct in_conninfo *, struct tcp_fastopen_ccache_bucket **);
static struct tcp_fastopen_ccache_entry *tcp_fastopen_ccache_create(
struct tcp_fastopen_ccache_bucket *, struct in_conninfo *, uint16_t, uint8_t,
uint8_t *);
static void tcp_fastopen_ccache_bucket_trim(struct tcp_fastopen_ccache_bucket *,
unsigned int);
static void tcp_fastopen_ccache_entry_drop(struct tcp_fastopen_ccache_entry *,
struct tcp_fastopen_ccache_bucket *);
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, fastopen, CTLFLAG_RW, 0, "TCP Fast Open");
static VNET_DEFINE(int, tcp_fastopen_acceptany) = 0;
#define V_tcp_fastopen_acceptany VNET(tcp_fastopen_acceptany)
SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, acceptany,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_fastopen_acceptany), 0,
"Accept any non-empty cookie");
static VNET_DEFINE(unsigned int, tcp_fastopen_autokey) = 120;
#define V_tcp_fastopen_autokey VNET(tcp_fastopen_autokey)
static int sysctl_net_inet_tcp_fastopen_autokey(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, autokey,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, NULL, 0,
&sysctl_net_inet_tcp_fastopen_autokey, "IU",
"Number of seconds between auto-generation of a new key; zero disables");
static int sysctl_net_inet_tcp_fastopen_ccache_bucket_limit(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, ccache_bucket_limit,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RWTUN, NULL, 0,
&sysctl_net_inet_tcp_fastopen_ccache_bucket_limit, "IU",
"Max entries per bucket in client cookie cache");
static VNET_DEFINE(unsigned int, tcp_fastopen_ccache_buckets) =
TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT;
#define V_tcp_fastopen_ccache_buckets VNET(tcp_fastopen_ccache_buckets)
SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, ccache_buckets,
CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_fastopen_ccache_buckets), 0,
"Client cookie cache number of buckets (power of 2)");
VNET_DEFINE(unsigned int, tcp_fastopen_client_enable) = 0;
static int sysctl_net_inet_tcp_fastopen_client_enable(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, client_enable,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, NULL, 0,
&sysctl_net_inet_tcp_fastopen_client_enable, "IU",
"Enable/disable TCP Fast Open client functionality");
SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, keylen,
CTLFLAG_RD, SYSCTL_NULL_INT_PTR, TCP_FASTOPEN_KEY_LEN,
"Key length in bytes");
SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, maxkeys,
CTLFLAG_RD, SYSCTL_NULL_INT_PTR, TCP_FASTOPEN_MAX_KEYS,
"Maximum number of keys supported");
SYSCTL_INT(_net_inet_tcp_fastopen, OID_AUTO, maxpsks,
CTLFLAG_RD, SYSCTL_NULL_INT_PTR, TCP_FASTOPEN_MAX_PSKS,
"Maximum number of pre-shared keys supported");
static VNET_DEFINE(unsigned int, tcp_fastopen_numkeys) = 0;
#define V_tcp_fastopen_numkeys VNET(tcp_fastopen_numkeys)
SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, numkeys,
CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(tcp_fastopen_numkeys), 0,
"Number of keys installed");
static VNET_DEFINE(unsigned int, tcp_fastopen_numpsks) = 0;
#define V_tcp_fastopen_numpsks VNET(tcp_fastopen_numpsks)
SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, numpsks,
CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(tcp_fastopen_numpsks), 0,
"Number of pre-shared keys installed");
static VNET_DEFINE(unsigned int, tcp_fastopen_path_disable_time) =
TCP_FASTOPEN_PATH_DISABLE_TIME_DEFAULT;
#define V_tcp_fastopen_path_disable_time VNET(tcp_fastopen_path_disable_time)
SYSCTL_UINT(_net_inet_tcp_fastopen, OID_AUTO, path_disable_time,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_fastopen_path_disable_time), 0,
"Seconds a TFO failure disables a {client_ip, server_ip, server_port} path");
static VNET_DEFINE(unsigned int, tcp_fastopen_psk_enable) = 0;
#define V_tcp_fastopen_psk_enable VNET(tcp_fastopen_psk_enable)
static int sysctl_net_inet_tcp_fastopen_psk_enable(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, psk_enable,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, NULL, 0,
&sysctl_net_inet_tcp_fastopen_psk_enable, "IU",
"Enable/disable TCP Fast Open server pre-shared key mode");
VNET_DEFINE(unsigned int, tcp_fastopen_server_enable) = 0;
static int sysctl_net_inet_tcp_fastopen_server_enable(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, server_enable,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, NULL, 0,
&sysctl_net_inet_tcp_fastopen_server_enable, "IU",
"Enable/disable TCP Fast Open server functionality");
static int sysctl_net_inet_tcp_fastopen_setkey(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, setkey,
CTLFLAG_VNET | CTLTYPE_OPAQUE | CTLFLAG_WR, NULL, 0,
&sysctl_net_inet_tcp_fastopen_setkey, "",
"Install a new key");
static int sysctl_net_inet_tcp_fastopen_setpsk(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_net_inet_tcp_fastopen, OID_AUTO, setpsk,
CTLFLAG_VNET | CTLTYPE_OPAQUE | CTLFLAG_WR, NULL, 0,
&sysctl_net_inet_tcp_fastopen_setpsk, "",
"Install a new pre-shared key");
static VNET_DEFINE(struct rmlock, tcp_fastopen_keylock);
#define V_tcp_fastopen_keylock VNET(tcp_fastopen_keylock)
#define TCP_FASTOPEN_KEYS_RLOCK(t) rm_rlock(&V_tcp_fastopen_keylock, (t))
#define TCP_FASTOPEN_KEYS_RUNLOCK(t) rm_runlock(&V_tcp_fastopen_keylock, (t))
#define TCP_FASTOPEN_KEYS_WLOCK() rm_wlock(&V_tcp_fastopen_keylock)
#define TCP_FASTOPEN_KEYS_WUNLOCK() rm_wunlock(&V_tcp_fastopen_keylock)
static VNET_DEFINE(struct tcp_fastopen_keylist, tcp_fastopen_keys);
#define V_tcp_fastopen_keys VNET(tcp_fastopen_keys)
static VNET_DEFINE(struct tcp_fastopen_callout, tcp_fastopen_autokey_ctx);
#define V_tcp_fastopen_autokey_ctx VNET(tcp_fastopen_autokey_ctx)
static VNET_DEFINE(uma_zone_t, counter_zone);
#define V_counter_zone VNET(counter_zone)
static MALLOC_DEFINE(M_TCP_FASTOPEN_CCACHE, "tfo_ccache", "TFO client cookie cache buckets");
static VNET_DEFINE(struct tcp_fastopen_ccache, tcp_fastopen_ccache);
#define V_tcp_fastopen_ccache VNET(tcp_fastopen_ccache)
#define CCB_LOCK(ccb) mtx_lock(&(ccb)->ccb_mtx)
#define CCB_UNLOCK(ccb) mtx_unlock(&(ccb)->ccb_mtx)
#define CCB_LOCK_ASSERT(ccb) mtx_assert(&(ccb)->ccb_mtx, MA_OWNED)
void
tcp_fastopen_init(void)
{
unsigned int i;
V_counter_zone = uma_zcreate("tfo", sizeof(unsigned int),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
rm_init(&V_tcp_fastopen_keylock, "tfo_keylock");
callout_init_rm(&V_tcp_fastopen_autokey_ctx.c,
&V_tcp_fastopen_keylock, 0);
V_tcp_fastopen_autokey_ctx.v = curvnet;
V_tcp_fastopen_keys.newest = TCP_FASTOPEN_MAX_KEYS - 1;
V_tcp_fastopen_keys.newest_psk = TCP_FASTOPEN_MAX_PSKS - 1;
/* May already be non-zero if kernel tunable was set */
if (V_tcp_fastopen_ccache.bucket_limit == 0)
V_tcp_fastopen_ccache.bucket_limit =
TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT;
/* May already be non-zero if kernel tunable was set */
if ((V_tcp_fastopen_ccache_buckets == 0) ||
!powerof2(V_tcp_fastopen_ccache_buckets))
V_tcp_fastopen_ccache.buckets =
TCP_FASTOPEN_CCACHE_BUCKETS_DEFAULT;
else
V_tcp_fastopen_ccache.buckets = V_tcp_fastopen_ccache_buckets;
V_tcp_fastopen_ccache.mask = V_tcp_fastopen_ccache.buckets - 1;
V_tcp_fastopen_ccache.secret = arc4random();
V_tcp_fastopen_ccache.base = malloc(V_tcp_fastopen_ccache.buckets *
sizeof(struct tcp_fastopen_ccache_bucket), M_TCP_FASTOPEN_CCACHE,
M_WAITOK | M_ZERO);
for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
TAILQ_INIT(&V_tcp_fastopen_ccache.base[i].ccb_entries);
mtx_init(&V_tcp_fastopen_ccache.base[i].ccb_mtx, "tfo_ccache_bucket",
NULL, MTX_DEF);
V_tcp_fastopen_ccache.base[i].ccb_num_entries = -1; /* bucket disabled */
V_tcp_fastopen_ccache.base[i].ccb_ccache = &V_tcp_fastopen_ccache;
}
/*
* Note that while the total number of entries in the cookie cache
* is limited by the table management logic to
* V_tcp_fastopen_ccache.buckets *
* V_tcp_fastopen_ccache.bucket_limit, the total number of items in
* this zone can exceed that amount by the number of CPUs in the
* system times the maximum number of unallocated items that can be
* present in each UMA per-CPU cache for this zone.
*/
V_tcp_fastopen_ccache.zone = uma_zcreate("tfo_ccache_entries",
sizeof(struct tcp_fastopen_ccache_entry), NULL, NULL, NULL, NULL,
UMA_ALIGN_CACHE, 0);
}
void
tcp_fastopen_destroy(void)
{
struct tcp_fastopen_ccache_bucket *ccb;
unsigned int i;
for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
ccb = &V_tcp_fastopen_ccache.base[i];
tcp_fastopen_ccache_bucket_trim(ccb, 0);
mtx_destroy(&ccb->ccb_mtx);
}
KASSERT(uma_zone_get_cur(V_tcp_fastopen_ccache.zone) == 0,
("%s: TFO ccache zone allocation count not 0", __func__));
uma_zdestroy(V_tcp_fastopen_ccache.zone);
free(V_tcp_fastopen_ccache.base, M_TCP_FASTOPEN_CCACHE);
callout_drain(&V_tcp_fastopen_autokey_ctx.c);
rm_destroy(&V_tcp_fastopen_keylock);
uma_zdestroy(V_counter_zone);
}
unsigned int *
tcp_fastopen_alloc_counter(void)
{
unsigned int *counter;
counter = uma_zalloc(V_counter_zone, M_NOWAIT);
if (counter)
*counter = 1;
return (counter);
}
void
tcp_fastopen_decrement_counter(unsigned int *counter)
{
if (*counter == 1)
uma_zfree(V_counter_zone, counter);
else
atomic_subtract_int(counter, 1);
}
static void
tcp_fastopen_addkey_locked(uint8_t *key)
{
V_tcp_fastopen_keys.newest++;
if (V_tcp_fastopen_keys.newest == TCP_FASTOPEN_MAX_KEYS)
V_tcp_fastopen_keys.newest = 0;
memcpy(V_tcp_fastopen_keys.key[V_tcp_fastopen_keys.newest], key,
TCP_FASTOPEN_KEY_LEN);
if (V_tcp_fastopen_numkeys < TCP_FASTOPEN_MAX_KEYS)
V_tcp_fastopen_numkeys++;
}
static void
tcp_fastopen_addpsk_locked(uint8_t *psk)
{
V_tcp_fastopen_keys.newest_psk++;
if (V_tcp_fastopen_keys.newest_psk == TCP_FASTOPEN_MAX_PSKS)
V_tcp_fastopen_keys.newest_psk = 0;
memcpy(V_tcp_fastopen_keys.psk[V_tcp_fastopen_keys.newest_psk], psk,
TCP_FASTOPEN_KEY_LEN);
if (V_tcp_fastopen_numpsks < TCP_FASTOPEN_MAX_PSKS)
V_tcp_fastopen_numpsks++;
}
static void
tcp_fastopen_autokey_locked(void)
{
uint8_t newkey[TCP_FASTOPEN_KEY_LEN];
arc4rand(newkey, TCP_FASTOPEN_KEY_LEN, 0);
tcp_fastopen_addkey_locked(newkey);
}
static void
tcp_fastopen_autokey_callout(void *arg)
{
struct tcp_fastopen_callout *ctx = arg;
CURVNET_SET(ctx->v);
tcp_fastopen_autokey_locked();
callout_reset(&ctx->c, V_tcp_fastopen_autokey * hz,
tcp_fastopen_autokey_callout, ctx);
CURVNET_RESTORE();
}
static uint64_t
tcp_fastopen_make_cookie(uint8_t key[SIPHASH_KEY_LENGTH], struct in_conninfo *inc)
{
SIPHASH_CTX ctx;
uint64_t siphash;
SipHash24_Init(&ctx);
SipHash_SetKey(&ctx, key);
switch (inc->inc_flags & INC_ISIPV6) {
#ifdef INET
case 0:
SipHash_Update(&ctx, &inc->inc_faddr, sizeof(inc->inc_faddr));
break;
#endif
#ifdef INET6
case INC_ISIPV6:
SipHash_Update(&ctx, &inc->inc6_faddr, sizeof(inc->inc6_faddr));
break;
#endif
}
SipHash_Final((u_int8_t *)&siphash, &ctx);
return (siphash);
}
static uint64_t
tcp_fastopen_make_psk_cookie(uint8_t *psk, uint8_t *cookie, uint8_t cookie_len)
{
SIPHASH_CTX ctx;
uint64_t psk_cookie;
SipHash24_Init(&ctx);
SipHash_SetKey(&ctx, psk);
SipHash_Update(&ctx, cookie, cookie_len);
SipHash_Final((u_int8_t *)&psk_cookie, &ctx);
return (psk_cookie);
}
static int
tcp_fastopen_find_cookie_match_locked(uint8_t *wire_cookie, uint64_t *cur_cookie)
{
unsigned int i, psk_index;
uint64_t psk_cookie;
if (V_tcp_fastopen_psk_enable) {
psk_index = V_tcp_fastopen_keys.newest_psk;
for (i = 0; i < V_tcp_fastopen_numpsks; i++) {
psk_cookie =
tcp_fastopen_make_psk_cookie(
V_tcp_fastopen_keys.psk[psk_index],
(uint8_t *)cur_cookie,
TCP_FASTOPEN_COOKIE_LEN);
if (memcmp(wire_cookie, &psk_cookie,
TCP_FASTOPEN_COOKIE_LEN) == 0)
return (1);
if (psk_index == 0)
psk_index = TCP_FASTOPEN_MAX_PSKS - 1;
else
psk_index--;
}
} else if (memcmp(wire_cookie, cur_cookie, TCP_FASTOPEN_COOKIE_LEN) == 0)
return (1);
return (0);
}
/*
* Return values:
* -1 the cookie is invalid and no valid cookie is available
* 0 the cookie is invalid and the latest cookie has been returned
* 1 the cookie is valid and the latest cookie has been returned
*/
int
tcp_fastopen_check_cookie(struct in_conninfo *inc, uint8_t *cookie,
unsigned int len, uint64_t *latest_cookie)
{
struct rm_priotracker tracker;
unsigned int i, key_index;
int rv;
uint64_t cur_cookie;
if (V_tcp_fastopen_acceptany) {
*latest_cookie = 0;
return (1);
}
TCP_FASTOPEN_KEYS_RLOCK(&tracker);
if (len != TCP_FASTOPEN_COOKIE_LEN) {
if (V_tcp_fastopen_numkeys > 0) {
*latest_cookie =
tcp_fastopen_make_cookie(
V_tcp_fastopen_keys.key[V_tcp_fastopen_keys.newest],
inc);
rv = 0;
} else
rv = -1;
goto out;
}
/*
* Check against each available key, from newest to oldest.
*/
key_index = V_tcp_fastopen_keys.newest;
for (i = 0; i < V_tcp_fastopen_numkeys; i++) {
cur_cookie =
tcp_fastopen_make_cookie(V_tcp_fastopen_keys.key[key_index],
inc);
if (i == 0)
*latest_cookie = cur_cookie;
rv = tcp_fastopen_find_cookie_match_locked(cookie, &cur_cookie);
if (rv)
goto out;
if (key_index == 0)
key_index = TCP_FASTOPEN_MAX_KEYS - 1;
else
key_index--;
}
rv = 0;
out:
TCP_FASTOPEN_KEYS_RUNLOCK(&tracker);
return (rv);
}
static int
sysctl_net_inet_tcp_fastopen_autokey(SYSCTL_HANDLER_ARGS)
{
int error;
unsigned int new;
new = V_tcp_fastopen_autokey;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (new > (INT_MAX / hz))
return (EINVAL);
TCP_FASTOPEN_KEYS_WLOCK();
if (V_tcp_fastopen_server_enable) {
if (V_tcp_fastopen_autokey && !new)
callout_stop(&V_tcp_fastopen_autokey_ctx.c);
else if (new)
callout_reset(&V_tcp_fastopen_autokey_ctx.c,
new * hz, tcp_fastopen_autokey_callout,
&V_tcp_fastopen_autokey_ctx);
}
V_tcp_fastopen_autokey = new;
TCP_FASTOPEN_KEYS_WUNLOCK();
}
return (error);
}
static int
sysctl_net_inet_tcp_fastopen_psk_enable(SYSCTL_HANDLER_ARGS)
{
int error;
unsigned int new;
new = V_tcp_fastopen_psk_enable;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (V_tcp_fastopen_psk_enable && !new) {
/* enabled -> disabled */
TCP_FASTOPEN_KEYS_WLOCK();
V_tcp_fastopen_numpsks = 0;
V_tcp_fastopen_keys.newest_psk =
TCP_FASTOPEN_MAX_PSKS - 1;
V_tcp_fastopen_psk_enable = 0;
TCP_FASTOPEN_KEYS_WUNLOCK();
} else if (!V_tcp_fastopen_psk_enable && new) {
/* disabled -> enabled */
TCP_FASTOPEN_KEYS_WLOCK();
V_tcp_fastopen_psk_enable = 1;
TCP_FASTOPEN_KEYS_WUNLOCK();
}
}
return (error);
}
static int
sysctl_net_inet_tcp_fastopen_server_enable(SYSCTL_HANDLER_ARGS)
{
int error;
unsigned int new;
new = V_tcp_fastopen_server_enable;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (V_tcp_fastopen_server_enable && !new) {
/* enabled -> disabled */
TCP_FASTOPEN_KEYS_WLOCK();
V_tcp_fastopen_numkeys = 0;
V_tcp_fastopen_keys.newest = TCP_FASTOPEN_MAX_KEYS - 1;
if (V_tcp_fastopen_autokey)
callout_stop(&V_tcp_fastopen_autokey_ctx.c);
V_tcp_fastopen_numpsks = 0;
V_tcp_fastopen_keys.newest_psk =
TCP_FASTOPEN_MAX_PSKS - 1;
V_tcp_fastopen_server_enable = 0;
TCP_FASTOPEN_KEYS_WUNLOCK();
} else if (!V_tcp_fastopen_server_enable && new) {
/* disabled -> enabled */
TCP_FASTOPEN_KEYS_WLOCK();
if (V_tcp_fastopen_autokey &&
(V_tcp_fastopen_numkeys == 0)) {
tcp_fastopen_autokey_locked();
callout_reset(&V_tcp_fastopen_autokey_ctx.c,
V_tcp_fastopen_autokey * hz,
tcp_fastopen_autokey_callout,
&V_tcp_fastopen_autokey_ctx);
}
V_tcp_fastopen_server_enable = 1;
TCP_FASTOPEN_KEYS_WUNLOCK();
}
}
return (error);
}
static int
sysctl_net_inet_tcp_fastopen_setkey(SYSCTL_HANDLER_ARGS)
{
int error;
uint8_t newkey[TCP_FASTOPEN_KEY_LEN];
if (req->oldptr != NULL || req->oldlen != 0)
return (EINVAL);
if (req->newptr == NULL)
return (EPERM);
if (req->newlen != sizeof(newkey))
return (EINVAL);
error = SYSCTL_IN(req, newkey, sizeof(newkey));
if (error)
return (error);
TCP_FASTOPEN_KEYS_WLOCK();
tcp_fastopen_addkey_locked(newkey);
TCP_FASTOPEN_KEYS_WUNLOCK();
return (0);
}
static int
sysctl_net_inet_tcp_fastopen_setpsk(SYSCTL_HANDLER_ARGS)
{
int error;
uint8_t newpsk[TCP_FASTOPEN_KEY_LEN];
if (req->oldptr != NULL || req->oldlen != 0)
return (EINVAL);
if (req->newptr == NULL)
return (EPERM);
if (req->newlen != sizeof(newpsk))
return (EINVAL);
error = SYSCTL_IN(req, newpsk, sizeof(newpsk));
if (error)
return (error);
TCP_FASTOPEN_KEYS_WLOCK();
tcp_fastopen_addpsk_locked(newpsk);
TCP_FASTOPEN_KEYS_WUNLOCK();
return (0);
}
static int
sysctl_net_inet_tcp_fastopen_ccache_bucket_limit(SYSCTL_HANDLER_ARGS)
{
struct tcp_fastopen_ccache_bucket *ccb;
int error;
unsigned int new;
unsigned int i;
new = V_tcp_fastopen_ccache.bucket_limit;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if ((new == 0) || (new > INT_MAX))
error = EINVAL;
else {
if (new < V_tcp_fastopen_ccache.bucket_limit) {
for (i = 0; i < V_tcp_fastopen_ccache.buckets;
i++) {
ccb = &V_tcp_fastopen_ccache.base[i];
tcp_fastopen_ccache_bucket_trim(ccb, new);
}
}
V_tcp_fastopen_ccache.bucket_limit = new;
}
}
return (error);
}
static int
sysctl_net_inet_tcp_fastopen_client_enable(SYSCTL_HANDLER_ARGS)
{
struct tcp_fastopen_ccache_bucket *ccb;
int error;
unsigned int new, i;
new = V_tcp_fastopen_client_enable;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (V_tcp_fastopen_client_enable && !new) {
/* enabled -> disabled */
for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
ccb = &V_tcp_fastopen_ccache.base[i];
tcp_fastopen_ccache_bucket_trim(ccb, 0);
}
V_tcp_fastopen_client_enable = 0;
} else if (!V_tcp_fastopen_client_enable && new) {
/* disabled -> enabled */
for (i = 0; i < V_tcp_fastopen_ccache.buckets; i++) {
ccb = &V_tcp_fastopen_ccache.base[i];
CCB_LOCK(ccb);
KASSERT(TAILQ_EMPTY(&ccb->ccb_entries),
("%s: ccb->ccb_entries not empty", __func__));
KASSERT(ccb->ccb_num_entries == -1,
("%s: ccb->ccb_num_entries %d not -1", __func__,
ccb->ccb_num_entries));
ccb->ccb_num_entries = 0; /* enable bucket */
CCB_UNLOCK(ccb);
}
V_tcp_fastopen_client_enable = 1;
}
}
return (error);
}
void
tcp_fastopen_connect(struct tcpcb *tp)
{
struct inpcb *inp;
struct tcp_fastopen_ccache_bucket *ccb;
struct tcp_fastopen_ccache_entry *cce;
sbintime_t now;
uint16_t server_mss;
uint64_t psk_cookie;
inp = tp->t_inpcb;
cce = tcp_fastopen_ccache_lookup(&inp->inp_inc, &ccb);
if (cce) {
if (cce->disable_time == 0) {
if ((cce->cookie_len > 0) &&
(tp->t_tfo_client_cookie_len ==
TCP_FASTOPEN_PSK_LEN)) {
psk_cookie =
tcp_fastopen_make_psk_cookie(
tp->t_tfo_cookie.client,
cce->cookie, cce->cookie_len);
} else {
tp->t_tfo_client_cookie_len = cce->cookie_len;
memcpy(tp->t_tfo_cookie.client, cce->cookie,
cce->cookie_len);
}
server_mss = cce->server_mss;
CCB_UNLOCK(ccb);
if (tp->t_tfo_client_cookie_len ==
TCP_FASTOPEN_PSK_LEN) {
tp->t_tfo_client_cookie_len =
TCP_FASTOPEN_COOKIE_LEN;
memcpy(tp->t_tfo_cookie.client, &psk_cookie,
TCP_FASTOPEN_COOKIE_LEN);
}
tcp_mss(tp, server_mss ? server_mss : -1);
tp->snd_wnd = tp->t_maxseg;
} else {
/*
* The path is disabled. Check the time and
* possibly re-enable.
*/
now = getsbinuptime();
if (now - cce->disable_time >
((sbintime_t)V_tcp_fastopen_path_disable_time << 32)) {
/*
* Re-enable path. Force a TFO cookie
* request. Forget the old MSS as it may be
* bogus now, and we will rediscover it in
* the SYN|ACK.
*/
cce->disable_time = 0;
cce->server_mss = 0;
cce->cookie_len = 0;
/*
* tp->t_tfo... cookie details are already
* zero from the tcpcb init.
*/
} else {
/*
* Path is disabled, so disable TFO on this
* connection.
*/
tp->t_flags &= ~TF_FASTOPEN;
}
CCB_UNLOCK(ccb);
tcp_mss(tp, -1);
/*
* snd_wnd is irrelevant since we are either forcing
* a TFO cookie request or disabling TFO - either
* way, no data with the SYN.
*/
}
} else {
/*
* A new entry for this path will be created when a SYN|ACK
* comes back, or the attempt otherwise fails.
*/
CCB_UNLOCK(ccb);
tcp_mss(tp, -1);
/*
* snd_wnd is irrelevant since we are forcing a TFO cookie
* request.
*/
}
}
void
tcp_fastopen_disable_path(struct tcpcb *tp)
{
struct in_conninfo *inc = &tp->t_inpcb->inp_inc;
struct tcp_fastopen_ccache_bucket *ccb;
struct tcp_fastopen_ccache_entry *cce;
cce = tcp_fastopen_ccache_lookup(inc, &ccb);
if (cce) {
cce->server_mss = 0;
cce->cookie_len = 0;
/*
* Preserve the existing disable time if it is already
* disabled.
*/
if (cce->disable_time == 0)
cce->disable_time = getsbinuptime();
} else /* use invalid cookie len to create disabled entry */
tcp_fastopen_ccache_create(ccb, inc, 0,
TCP_FASTOPEN_MAX_COOKIE_LEN + 1, NULL);
CCB_UNLOCK(ccb);
tp->t_flags &= ~TF_FASTOPEN;
}
void
tcp_fastopen_update_cache(struct tcpcb *tp, uint16_t mss,
uint8_t cookie_len, uint8_t *cookie)
{
struct in_conninfo *inc = &tp->t_inpcb->inp_inc;
struct tcp_fastopen_ccache_bucket *ccb;
struct tcp_fastopen_ccache_entry *cce;
cce = tcp_fastopen_ccache_lookup(inc, &ccb);
if (cce) {
if ((cookie_len >= TCP_FASTOPEN_MIN_COOKIE_LEN) &&
(cookie_len <= TCP_FASTOPEN_MAX_COOKIE_LEN) &&
((cookie_len & 0x1) == 0)) {
cce->server_mss = mss;
cce->cookie_len = cookie_len;
memcpy(cce->cookie, cookie, cookie_len);
cce->disable_time = 0;
} else {
/* invalid cookie length, disable entry */
cce->server_mss = 0;
cce->cookie_len = 0;
/*
* Preserve the existing disable time if it is
* already disabled.
*/
if (cce->disable_time == 0)
cce->disable_time = getsbinuptime();
}
} else
tcp_fastopen_ccache_create(ccb, inc, mss, cookie_len, cookie);
CCB_UNLOCK(ccb);
}
static struct tcp_fastopen_ccache_entry *
tcp_fastopen_ccache_lookup(struct in_conninfo *inc,
struct tcp_fastopen_ccache_bucket **ccbp)
{
struct tcp_fastopen_ccache_bucket *ccb;
struct tcp_fastopen_ccache_entry *cce;
uint32_t last_word;
uint32_t hash;
hash = jenkins_hash32((uint32_t *)&inc->inc_ie.ie_dependladdr, 4,
V_tcp_fastopen_ccache.secret);
hash = jenkins_hash32((uint32_t *)&inc->inc_ie.ie_dependfaddr, 4,
hash);
last_word = inc->inc_fport;
hash = jenkins_hash32(&last_word, 1, hash);
ccb = &V_tcp_fastopen_ccache.base[hash & V_tcp_fastopen_ccache.mask];
*ccbp = ccb;
CCB_LOCK(ccb);
/*
* Always returns with locked bucket.
*/
TAILQ_FOREACH(cce, &ccb->ccb_entries, cce_link)
if ((!(cce->af == AF_INET6) == !(inc->inc_flags & INC_ISIPV6)) &&
(cce->server_port == inc->inc_ie.ie_fport) &&
(((cce->af == AF_INET) &&
(cce->cce_client_ip.v4.s_addr == inc->inc_laddr.s_addr) &&
(cce->cce_server_ip.v4.s_addr == inc->inc_faddr.s_addr)) ||
((cce->af == AF_INET6) &&
IN6_ARE_ADDR_EQUAL(&cce->cce_client_ip.v6, &inc->inc6_laddr) &&
IN6_ARE_ADDR_EQUAL(&cce->cce_server_ip.v6, &inc->inc6_faddr))))
break;
return (cce);
}
static struct tcp_fastopen_ccache_entry *
tcp_fastopen_ccache_create(struct tcp_fastopen_ccache_bucket *ccb,
struct in_conninfo *inc, uint16_t mss, uint8_t cookie_len, uint8_t *cookie)
{
struct tcp_fastopen_ccache_entry *cce;
/*
* 1. Create a new entry, or
* 2. Reclaim an existing entry, or
* 3. Fail
*/
CCB_LOCK_ASSERT(ccb);
cce = NULL;
if (ccb->ccb_num_entries < V_tcp_fastopen_ccache.bucket_limit)
cce = uma_zalloc(V_tcp_fastopen_ccache.zone, M_NOWAIT);
if (cce == NULL) {
/*
* At bucket limit, or out of memory - reclaim last
* entry in bucket.
*/
cce = TAILQ_LAST(&ccb->ccb_entries, bucket_entries);
if (cce == NULL) {
/* XXX count this event */
return (NULL);
}
TAILQ_REMOVE(&ccb->ccb_entries, cce, cce_link);
} else
ccb->ccb_num_entries++;
TAILQ_INSERT_HEAD(&ccb->ccb_entries, cce, cce_link);
cce->af = (inc->inc_flags & INC_ISIPV6) ? AF_INET6 : AF_INET;
if (cce->af == AF_INET) {
cce->cce_client_ip.v4 = inc->inc_laddr;
cce->cce_server_ip.v4 = inc->inc_faddr;
} else {
cce->cce_client_ip.v6 = inc->inc6_laddr;
cce->cce_server_ip.v6 = inc->inc6_faddr;
}
cce->server_port = inc->inc_fport;
if ((cookie_len >= TCP_FASTOPEN_MIN_COOKIE_LEN) &&
(cookie_len <= TCP_FASTOPEN_MAX_COOKIE_LEN) &&
((cookie_len & 0x1) == 0)) {
cce->server_mss = mss;
cce->cookie_len = cookie_len;
memcpy(cce->cookie, cookie, cookie_len);
cce->disable_time = 0;
} else {
/* invalid cookie length, disable cce */
cce->server_mss = 0;
cce->cookie_len = 0;
cce->disable_time = getsbinuptime();
}
return (cce);
}
static void
tcp_fastopen_ccache_bucket_trim(struct tcp_fastopen_ccache_bucket *ccb,
unsigned int limit)
{
struct tcp_fastopen_ccache_entry *cce, *cce_tmp;
unsigned int entries;
CCB_LOCK(ccb);
entries = 0;
TAILQ_FOREACH_SAFE(cce, &ccb->ccb_entries, cce_link, cce_tmp) {
entries++;
if (entries > limit)
tcp_fastopen_ccache_entry_drop(cce, ccb);
}
KASSERT(ccb->ccb_num_entries <= (int)limit,
("%s: ccb->ccb_num_entries %d exceeds limit %d", __func__,
ccb->ccb_num_entries, limit));
if (limit == 0) {
KASSERT(TAILQ_EMPTY(&ccb->ccb_entries),
("%s: ccb->ccb_entries not empty", __func__));
ccb->ccb_num_entries = -1; /* disable bucket */
}
CCB_UNLOCK(ccb);
}
static void
tcp_fastopen_ccache_entry_drop(struct tcp_fastopen_ccache_entry *cce,
struct tcp_fastopen_ccache_bucket *ccb)
{
CCB_LOCK_ASSERT(ccb);
TAILQ_REMOVE(&ccb->ccb_entries, cce, cce_link);
ccb->ccb_num_entries--;
uma_zfree(V_tcp_fastopen_ccache.zone, cce);
}
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