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>
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 1888169..12948f5 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -243,6 +243,16 @@
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;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 85c5090..5aed371 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -170,6 +170,11 @@
#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 @@
#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_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 @@
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);
/*
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index a677d80..ae2ccf2 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -7,7 +7,7 @@
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 \
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index eab2a7f..650e152 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -293,7 +293,7 @@
/* 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;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 3f6a1e7..5840c32 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -367,6 +367,13 @@
},
#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,
.maxlen = sizeof(int),
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
new file mode 100644
index 0000000..a7f729c
--- /dev/null
+++ b/net/ipv4/tcp_fastopen.c
@@ -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);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index fdd49f1..a06bb89 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3732,7 +3732,8 @@
* 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 @@
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 @@
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 @@
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:
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d7d2fa5..01aa77a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1307,7 +1307,7 @@
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 &&
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index c66f2ed..5912ac3 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -97,7 +97,7 @@
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 @@
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;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 15a7c7b..4849be7 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -385,15 +385,17 @@
#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 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 @@
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
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 7bf3cc4..bb46061 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -177,7 +177,7 @@
/* 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;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c9dabdd..0302ec3 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1033,7 +1033,7 @@
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 &&