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net-tcp: Fast Open base 

This patch impelements the common code for both the client and server.

1. TCP Fast Open option processing. Since Fast Open does not have an
   option number assigned by IANA yet, it shares the experiment option
   code 254 by implementing draft-ietf-tcpm-experimental-options
   with a 16 bits magic number 0xF989. This enables global experiments
   without clashing the scarce(2) experimental options available for TCP.

   When the draft status becomes standard (maybe), the client should
   switch to the new option number assigned while the server supports
   both numbers for transistion.

2. The new sysctl tcp_fastopen

3. A place holder init function

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yuchung Cheng 2012-07-19 06:43:05 +00:00 committed by David S. Miller
parent 4cce66cdd1
commit 2100c8d2d9
12 changed files with 86 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/tcp.h
View File

@ -243,6 +243,16 @@ static inline unsigned int tcp_optlen(const struct sk_buff *skb)
return (tcp_hdr(skb)->doff - 5) * 4;
}
/* TCP Fast Open */
#define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */
#define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */
/* TCP Fast Open Cookie as stored in memory */
struct tcp_fastopen_cookie {
s8 len;
u8 val[TCP_FASTOPEN_COOKIE_MAX];
};
/* This defines a selective acknowledgement block. */
struct tcp_sack_block_wire {
__be32 start_seq;

9
include/net/tcp.h
View File

@ -170,6 +170,11 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
#define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */
#define TCPOPT_EXP 254 /* Experimental */
/* Magic number to be after the option value for sharing TCP
* experimental options. See draft-ietf-tcpm-experimental-options-00.txt
*/
#define TCPOPT_FASTOPEN_MAGIC 0xF989
/*
* TCP option lengths
@ -180,6 +185,7 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
#define TCPOLEN_SACK_PERM 2
#define TCPOLEN_TIMESTAMP 10
#define TCPOLEN_MD5SIG 18
#define TCPOLEN_EXP_FASTOPEN_BASE 4
#define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */
#define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */
#define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN)
@ -222,6 +228,7 @@ extern int sysctl_tcp_retries1;
extern int sysctl_tcp_retries2;
extern int sysctl_tcp_orphan_retries;
extern int sysctl_tcp_syncookies;
extern int sysctl_tcp_fastopen;
extern int sysctl_tcp_retrans_collapse;
extern int sysctl_tcp_stdurg;
extern int sysctl_tcp_rfc1337;
@ -418,7 +425,7 @@ extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
size_t len, int nonblock, int flags, int *addr_len);
extern void tcp_parse_options(const struct sk_buff *skb,
struct tcp_options_received *opt_rx, const u8 **hvpp,
int estab);
int estab, struct tcp_fastopen_cookie *foc);
extern const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
/*

2
net/ipv4/Makefile
View File

@ -7,7 +7,7 @@ obj-y := route.o inetpeer.o protocol.o \
ip_output.o ip_sockglue.o inet_hashtables.o \
inet_timewait_sock.o inet_connection_sock.o \
tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
tcp_minisocks.o tcp_cong.o tcp_metrics.o \
tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \
datagram.o raw.o udp.o udplite.o \
arp.o icmp.o devinet.o af_inet.o igmp.o \
fib_frontend.o fib_semantics.o fib_trie.o \

2
net/ipv4/syncookies.c
View File

@ -293,7 +293,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
/* check for timestamp cookie support */
memset(&tcp_opt, 0, sizeof(tcp_opt));
tcp_parse_options(skb, &tcp_opt, &hash_location, 0);
tcp_parse_options(skb, &tcp_opt, &hash_location, 0, NULL);
if (!cookie_check_timestamp(&tcp_opt, &ecn_ok))
goto out;

7
net/ipv4/sysctl_net_ipv4.c
View File

@ -366,6 +366,13 @@ static struct ctl_table ipv4_table[] = {
.proc_handler = proc_dointvec
},
#endif
{
.procname = "tcp_fastopen",
.data = &sysctl_tcp_fastopen,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "tcp_tw_recycle",
.data = &tcp_death_row.sysctl_tw_recycle,

11
net/ipv4/tcp_fastopen.c Normal file
View File

@ -0,0 +1,11 @@
#include <linux/init.h>
#include <linux/kernel.h>
int sysctl_tcp_fastopen;
static int __init tcp_fastopen_init(void)
{
return 0;
}
late_initcall(tcp_fastopen_init);

26
net/ipv4/tcp_input.c
View File

@ -3732,7 +3732,8 @@ old_ack:
* 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)
const u8 **hvpp, int estab,
struct tcp_fastopen_cookie *foc)
{
const unsigned char *ptr;
const struct tcphdr *th = tcp_hdr(skb);
@ -3839,8 +3840,25 @@ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *o
break;
}
break;
}
case TCPOPT_EXP:
/* Fast Open option shares code 254 using a
* 16 bits magic number. It's valid only in
* SYN or SYN-ACK with an even size.
*/
if (opsize < TCPOLEN_EXP_FASTOPEN_BASE ||
get_unaligned_be16(ptr) != TCPOPT_FASTOPEN_MAGIC ||
foc == NULL || !th->syn || (opsize & 1))
break;
foc->len = opsize - TCPOLEN_EXP_FASTOPEN_BASE;
if (foc->len >= TCP_FASTOPEN_COOKIE_MIN &&
foc->len <= TCP_FASTOPEN_COOKIE_MAX)
memcpy(foc->val, ptr + 2, foc->len);
else if (foc->len != 0)
foc->len = -1;
break;
}
ptr += opsize-2;
length -= opsize;
}
@ -3882,7 +3900,7 @@ static bool tcp_fast_parse_options(const struct sk_buff *skb,
if (tcp_parse_aligned_timestamp(tp, th))
return true;
}
tcp_parse_options(skb, &tp->rx_opt, hvpp, 1);
tcp_parse_options(skb, &tp->rx_opt, hvpp, 1, NULL);
return true;
}
@ -5637,7 +5655,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
struct tcp_cookie_values *cvp = tp->cookie_values;
int saved_clamp = tp->rx_opt.mss_clamp;
tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0);
tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, NULL);
if (th->ack) {
/* rfc793:

2
net/ipv4/tcp_ipv4.c
View File

@ -1307,7 +1307,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
tcp_clear_options(&tmp_opt);
tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
tmp_opt.user_mss = tp->rx_opt.user_mss;
tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
if (tmp_opt.cookie_plus > 0 &&
tmp_opt.saw_tstamp &&

4
net/ipv4/tcp_minisocks.c
View File

@ -97,7 +97,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
tmp_opt.saw_tstamp = 0;
if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
if (tmp_opt.saw_tstamp) {
tmp_opt.ts_recent = tcptw->tw_ts_recent;
@ -534,7 +534,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
tmp_opt.saw_tstamp = 0;
if (th->doff > (sizeof(struct tcphdr)>>2)) {
tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
if (tmp_opt.saw_tstamp) {
tmp_opt.ts_recent = req->ts_recent;

25
net/ipv4/tcp_output.c
View File

@ -385,15 +385,17 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)
#define OPTION_MD5 (1 << 2)
#define OPTION_WSCALE (1 << 3)
#define OPTION_COOKIE_EXTENSION (1 << 4)
#define OPTION_FAST_OPEN_COOKIE (1 << 8)
struct tcp_out_options {
u8 options; /* bit field of OPTION_* */
u16 options; /* bit field of OPTION_* */
u16 mss; /* 0 to disable */
u8 ws; /* window scale, 0 to disable */
u8 num_sack_blocks; /* number of SACK blocks to include */
u8 hash_size; /* bytes in hash_location */
u16 mss; /* 0 to disable */
__u32 tsval, tsecr; /* need to include OPTION_TS */
__u8 *hash_location; /* temporary pointer, overloaded */
__u32 tsval, tsecr; /* need to include OPTION_TS */
struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */
};
/* The sysctl int routines are generic, so check consistency here.
@ -442,7 +444,7 @@ static u8 tcp_cookie_size_check(u8 desired)
static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
struct tcp_out_options *opts)
{
u8 options = opts->options; /* mungable copy */
u16 options = opts->options; /* mungable copy */
/* Having both authentication and cookies for security is redundant,
* and there's certainly not enough room. Instead, the cookie-less
@ -564,6 +566,21 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
tp->rx_opt.dsack = 0;
}
if (unlikely(OPTION_FAST_OPEN_COOKIE & options)) {
struct tcp_fastopen_cookie *foc = opts->fastopen_cookie;
*ptr++ = htonl((TCPOPT_EXP << 24) |
((TCPOLEN_EXP_FASTOPEN_BASE + foc->len) << 16) |
TCPOPT_FASTOPEN_MAGIC);
memcpy(ptr, foc->val, foc->len);
if ((foc->len & 3) == 2) {
u8 *align = ((u8 *)ptr) + foc->len;
align[0] = align[1] = TCPOPT_NOP;
}
ptr += (foc->len + 3) >> 2;
}
}
/* Compute TCP options for SYN packets. This is not the final

2
net/ipv6/syncookies.c
View File

@ -177,7 +177,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
/* check for timestamp cookie support */
memset(&tcp_opt, 0, sizeof(tcp_opt));
tcp_parse_options(skb, &tcp_opt, &hash_location, 0);
tcp_parse_options(skb, &tcp_opt, &hash_location, 0, NULL);
if (!cookie_check_timestamp(&tcp_opt, &ecn_ok))
goto out;

2
net/ipv6/tcp_ipv6.c
View File

@ -1033,7 +1033,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
tcp_clear_options(&tmp_opt);
tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
tmp_opt.user_mss = tp->rx_opt.user_mss;
tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
if (tmp_opt.cookie_plus > 0 &&
tmp_opt.saw_tstamp &&