tcp: Remove TCPCT
TCPCT uses option-number 253, reserved for experimental use and should
not be used in production environments.
Further, TCPCT does not fully implement RFC 6013.
As a nice side-effect, removing TCPCT increases TCP's performance for
very short flows:
Doing an apache-benchmark with -c 100 -n 100000, sending HTTP-requests
for files of 1KB size.
before this patch:
average (among 7 runs) of 20845.5 Requests/Second
after:
average (among 7 runs) of 21403.6 Requests/Second
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 836d74d..19f0149 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3760,8 +3760,8 @@
* But, this can also be called on packets in the established flow when
* the fast version below fails.
*/
-void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *opt_rx,
- const u8 **hvpp, int estab,
+void tcp_parse_options(const struct sk_buff *skb,
+ struct tcp_options_received *opt_rx, int estab,
struct tcp_fastopen_cookie *foc)
{
const unsigned char *ptr;
@@ -3845,31 +3845,6 @@
*/
break;
#endif
- case TCPOPT_COOKIE:
- /* This option is variable length.
- */
- switch (opsize) {
- case TCPOLEN_COOKIE_BASE:
- /* not yet implemented */
- break;
- case TCPOLEN_COOKIE_PAIR:
- /* not yet implemented */
- break;
- case TCPOLEN_COOKIE_MIN+0:
- case TCPOLEN_COOKIE_MIN+2:
- case TCPOLEN_COOKIE_MIN+4:
- case TCPOLEN_COOKIE_MIN+6:
- case TCPOLEN_COOKIE_MAX:
- /* 16-bit multiple */
- opt_rx->cookie_plus = opsize;
- *hvpp = ptr;
- break;
- default:
- /* ignore option */
- break;
- }
- break;
-
case TCPOPT_EXP:
/* Fast Open option shares code 254 using a
* 16 bits magic number. It's valid only in
@@ -3915,8 +3890,7 @@
* If it is wrong it falls back on tcp_parse_options().
*/
static bool tcp_fast_parse_options(const struct sk_buff *skb,
- const struct tcphdr *th,
- struct tcp_sock *tp, const u8 **hvpp)
+ const struct tcphdr *th, struct tcp_sock *tp)
{
/* In the spirit of fast parsing, compare doff directly to constant
* values. Because equality is used, short doff can be ignored here.
@@ -3930,7 +3904,7 @@
return true;
}
- tcp_parse_options(skb, &tp->rx_opt, hvpp, 1, NULL);
+ tcp_parse_options(skb, &tp->rx_opt, 1, NULL);
if (tp->rx_opt.saw_tstamp)
tp->rx_opt.rcv_tsecr -= tp->tsoffset;
@@ -5311,12 +5285,10 @@
static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th, int syn_inerr)
{
- const u8 *hash_location;
struct tcp_sock *tp = tcp_sk(sk);
/* RFC1323: H1. Apply PAWS check first. */
- if (tcp_fast_parse_options(skb, th, tp, &hash_location) &&
- tp->rx_opt.saw_tstamp &&
+ if (tcp_fast_parse_options(skb, th, tp) && tp->rx_opt.saw_tstamp &&
tcp_paws_discard(sk, skb)) {
if (!th->rst) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED);
@@ -5670,12 +5642,11 @@
if (mss == tp->rx_opt.user_mss) {
struct tcp_options_received opt;
- const u8 *hash_location;
/* Get original SYNACK MSS value if user MSS sets mss_clamp */
tcp_clear_options(&opt);
opt.user_mss = opt.mss_clamp = 0;
- tcp_parse_options(synack, &opt, &hash_location, 0, NULL);
+ tcp_parse_options(synack, &opt, 0, NULL);
mss = opt.mss_clamp;
}
@@ -5706,14 +5677,12 @@
static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th, unsigned int len)
{
- const u8 *hash_location;
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
- struct tcp_cookie_values *cvp = tp->cookie_values;
struct tcp_fastopen_cookie foc = { .len = -1 };
int saved_clamp = tp->rx_opt.mss_clamp;
- tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, &foc);
+ tcp_parse_options(skb, &tp->rx_opt, 0, &foc);
if (tp->rx_opt.saw_tstamp)
tp->rx_opt.rcv_tsecr -= tp->tsoffset;
@@ -5810,30 +5779,6 @@
* is initialized. */
tp->copied_seq = tp->rcv_nxt;
- if (cvp != NULL &&
- cvp->cookie_pair_size > 0 &&
- tp->rx_opt.cookie_plus > 0) {
- int cookie_size = tp->rx_opt.cookie_plus
- - TCPOLEN_COOKIE_BASE;
- int cookie_pair_size = cookie_size
- + cvp->cookie_desired;
-
- /* A cookie extension option was sent and returned.
- * Note that each incoming SYNACK replaces the
- * Responder cookie. The initial exchange is most
- * fragile, as protection against spoofing relies
- * entirely upon the sequence and timestamp (above).
- * This replacement strategy allows the correct pair to
- * pass through, while any others will be filtered via
- * Responder verification later.
- */
- if (sizeof(cvp->cookie_pair) >= cookie_pair_size) {
- memcpy(&cvp->cookie_pair[cvp->cookie_desired],
- hash_location, cookie_size);
- cvp->cookie_pair_size = cookie_pair_size;
- }
- }
-
smp_mb();
tcp_finish_connect(sk, skb);
