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tcp: Remove TCPCT

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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>
This commit is contained in:
Christoph Paasch
2013-03-17 08:23:34 +00:00
committed by David S. Miller
parent 94d8f2b133
commit 1a2c6181c4
18 changed files with 37 additions and 840 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/ipv4/tcp_input.c
+7 -62
View File
@@ -3760,8 +3760,8 @@ old_ack:
* 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 @@ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *o
*/
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 @@ static bool tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr
* 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 @@ static bool tcp_fast_parse_options(const struct sk_buff *skb,
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 @@ out:
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 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
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 bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
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 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
* 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);