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-rw-r--r--net/ipv4/tcp_input.c29
-rw-r--r--net/ipv4/tcp_metrics.c13
-rw-r--r--net/ipv4/tcp_output.c6
-rw-r--r--net/ipv4/tcp_timer.c2
4 files changed, 36 insertions, 14 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 24f1630b2afb..031cf72cd05c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5378,8 +5378,8 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *data = tp->syn_data ? tcp_write_queue_head(sk) : NULL;
- u16 mss = tp->rx_opt.mss_clamp;
- bool syn_drop;
+ u16 mss = tp->rx_opt.mss_clamp, try_exp = 0;
+ bool syn_drop = false;
if (mss == tp->rx_opt.user_mss) {
struct tcp_options_received opt;
@@ -5391,16 +5391,25 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
mss = opt.mss_clamp;
}
- if (!tp->syn_fastopen) /* Ignore an unsolicited cookie */
+ if (!tp->syn_fastopen) {
+ /* Ignore an unsolicited cookie */
cookie->len = -1;
+ } else if (tp->total_retrans) {
+ /* SYN timed out and the SYN-ACK neither has a cookie nor
+ * acknowledges data. Presumably the remote received only
+ * the retransmitted (regular) SYNs: either the original
+ * SYN-data or the corresponding SYN-ACK was dropped.
+ */
+ syn_drop = (cookie->len < 0 && data);
+ } else if (cookie->len < 0 && !tp->syn_data) {
+ /* We requested a cookie but didn't get it. If we did not use
+ * the (old) exp opt format then try so next time (try_exp=1).
+ * Otherwise we go back to use the RFC7413 opt (try_exp=2).
+ */
+ try_exp = tp->syn_fastopen_exp ? 2 : 1;
+ }
- /* The SYN-ACK neither has cookie nor acknowledges the data. Presumably
- * the remote receives only the retransmitted (regular) SYNs: either
- * the original SYN-data or the corresponding SYN-ACK is lost.
- */
- syn_drop = (cookie->len <= 0 && data && tp->total_retrans);
-
- tcp_fastopen_cache_set(sk, mss, cookie, syn_drop);
+ tcp_fastopen_cache_set(sk, mss, cookie, syn_drop, try_exp);
if (data) { /* Retransmit unacked data in SYN */
tcp_for_write_queue_from(data, sk) {
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 78ecc4a01712..a51d63a43e33 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -28,7 +28,8 @@ static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *s
struct tcp_fastopen_metrics {
u16 mss;
- u16 syn_loss:10; /* Recurring Fast Open SYN losses */
+ u16 syn_loss:10, /* Recurring Fast Open SYN losses */
+ try_exp:2; /* Request w/ exp. option (once) */
unsigned long last_syn_loss; /* Last Fast Open SYN loss */
struct tcp_fastopen_cookie cookie;
};
@@ -131,6 +132,8 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm,
if (fastopen_clear) {
tm->tcpm_fastopen.mss = 0;
tm->tcpm_fastopen.syn_loss = 0;
+ tm->tcpm_fastopen.try_exp = 0;
+ tm->tcpm_fastopen.cookie.exp = false;
tm->tcpm_fastopen.cookie.len = 0;
}
}
@@ -713,6 +716,8 @@ void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
if (tfom->mss)
*mss = tfom->mss;
*cookie = tfom->cookie;
+ if (cookie->len <= 0 && tfom->try_exp == 1)
+ cookie->exp = true;
*syn_loss = tfom->syn_loss;
*last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
} while (read_seqretry(&fastopen_seqlock, seq));
@@ -721,7 +726,8 @@ void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
}
void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
- struct tcp_fastopen_cookie *cookie, bool syn_lost)
+ struct tcp_fastopen_cookie *cookie, bool syn_lost,
+ u16 try_exp)
{
struct dst_entry *dst = __sk_dst_get(sk);
struct tcp_metrics_block *tm;
@@ -738,6 +744,9 @@ void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
tfom->mss = mss;
if (cookie && cookie->len > 0)
tfom->cookie = *cookie;
+ else if (try_exp > tfom->try_exp &&
+ tfom->cookie.len <= 0 && !tfom->cookie.exp)
+ tfom->try_exp = try_exp;
if (syn_lost) {
++tfom->syn_loss;
tfom->last_syn_loss = jiffies;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 464bd8c5de69..e662d85d1635 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -592,13 +592,17 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
}
if (fastopen && fastopen->cookie.len >= 0) {
- u32 need = TCPOLEN_EXP_FASTOPEN_BASE + fastopen->cookie.len;
+ u32 need = fastopen->cookie.len;
+
+ need += fastopen->cookie.exp ? TCPOLEN_EXP_FASTOPEN_BASE :
+ TCPOLEN_FASTOPEN_BASE;
need = (need + 3) & ~3U; /* Align to 32 bits */
if (remaining >= need) {
opts->options |= OPTION_FAST_OPEN_COOKIE;
opts->fastopen_cookie = &fastopen->cookie;
remaining -= need;
tp->syn_fastopen = 1;
+ tp->syn_fastopen_exp = fastopen->cookie.exp ? 1 : 0;
}
}
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 2568fd282873..8c65dc147d8b 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -167,7 +167,7 @@ static int tcp_write_timeout(struct sock *sk)
if (icsk->icsk_retransmits) {
dst_negative_advice(sk);
if (tp->syn_fastopen || tp->syn_data)
- tcp_fastopen_cache_set(sk, 0, NULL, true);
+ tcp_fastopen_cache_set(sk, 0, NULL, true, 0);
if (tp->syn_data)
NET_INC_STATS_BH(sock_net(sk),
LINUX_MIB_TCPFASTOPENACTIVEFAIL);