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-rw-r--r--include/linux/snmp.h1
-rw-r--r--include/linux/tcp.h6
-rw-r--r--include/net/tcp.h9
-rw-r--r--net/ipv4/af_inet.c10
-rw-r--r--net/ipv4/proc.c1
-rw-r--r--net/ipv4/tcp_output.c115
6 files changed, 130 insertions, 12 deletions
diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index e5fcbd079e4a..00bc189cb395 100644
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -238,6 +238,7 @@ enum
LINUX_MIB_TCPOFOMERGE, /* TCPOFOMerge */
LINUX_MIB_TCPCHALLENGEACK, /* TCPChallengeACK */
LINUX_MIB_TCPSYNCHALLENGE, /* TCPSYNChallenge */
+ LINUX_MIB_TCPFASTOPENACTIVE, /* TCPFastOpenActive */
__LINUX_MIB_MAX
};
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 12948f543839..1edf96afab44 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -386,7 +386,8 @@ struct tcp_sock {
unused : 1;
u8 repair_queue;
u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */
- early_retrans_delayed:1; /* Delayed ER timer installed */
+ early_retrans_delayed:1, /* Delayed ER timer installed */
+ syn_fastopen:1; /* SYN includes Fast Open option */
/* RTT measurement */
u32 srtt; /* smoothed round trip time << 3 */
@@ -500,6 +501,9 @@ struct tcp_sock {
struct tcp_md5sig_info __rcu *md5sig_info;
#endif
+/* TCP fastopen related information */
+ struct tcp_fastopen_request *fastopen_req;
+
/* When the cookie options are generated and exchanged, then this
* object holds a reference to them (cookie_values->kref). Also
* contains related tcp_cookie_transactions fields.
diff --git a/include/net/tcp.h b/include/net/tcp.h
index e601da197361..867557b4244a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1289,6 +1289,15 @@ extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff
extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
const struct tcp_md5sig_key *key);
+struct tcp_fastopen_request {
+ /* Fast Open cookie. Size 0 means a cookie request */
+ struct tcp_fastopen_cookie cookie;
+ struct msghdr *data; /* data in MSG_FASTOPEN */
+ u16 copied; /* queued in tcp_connect() */
+};
+
+void tcp_free_fastopen_req(struct tcp_sock *tp);
+
/* write queue abstraction */
static inline void tcp_write_queue_purge(struct sock *sk)
{
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 07a02f6e9696..edc414625be2 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -556,11 +556,12 @@ int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr,
}
EXPORT_SYMBOL(inet_dgram_connect);
-static long inet_wait_for_connect(struct sock *sk, long timeo)
+static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias)
{
DEFINE_WAIT(wait);
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ sk->sk_write_pending += writebias;
/* Basic assumption: if someone sets sk->sk_err, he _must_
* change state of the socket from TCP_SYN_*.
@@ -576,6 +577,7 @@ static long inet_wait_for_connect(struct sock *sk, long timeo)
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
}
finish_wait(sk_sleep(sk), &wait);
+ sk->sk_write_pending -= writebias;
return timeo;
}
@@ -634,8 +636,12 @@ int inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
+ int writebias = (sk->sk_protocol == IPPROTO_TCP) &&
+ tcp_sk(sk)->fastopen_req &&
+ tcp_sk(sk)->fastopen_req->data ? 1 : 0;
+
/* Error code is set above */
- if (!timeo || !inet_wait_for_connect(sk, timeo))
+ if (!timeo || !inet_wait_for_connect(sk, timeo, writebias))
goto out;
err = sock_intr_errno(timeo);
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 2a5240b2ea61..957acd12250b 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -262,6 +262,7 @@ static const struct snmp_mib snmp4_net_list[] = {
SNMP_MIB_ITEM("TCPOFOMerge", LINUX_MIB_TCPOFOMERGE),
SNMP_MIB_ITEM("TCPChallengeACK", LINUX_MIB_TCPCHALLENGEACK),
SNMP_MIB_ITEM("TCPSYNChallenge", LINUX_MIB_TCPSYNCHALLENGE),
+ SNMP_MIB_ITEM("TCPFastOpenActive", LINUX_MIB_TCPFASTOPENACTIVE),
SNMP_MIB_SENTINEL
};
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 4849be76ccd6..88693281da4c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -596,6 +596,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
u8 cookie_size = (!tp->rx_opt.cookie_out_never && cvp != NULL) ?
tcp_cookie_size_check(cvp->cookie_desired) :
0;
+ struct tcp_fastopen_request *fastopen = tp->fastopen_req;
#ifdef CONFIG_TCP_MD5SIG
*md5 = tp->af_specific->md5_lookup(sk, sk);
@@ -636,6 +637,16 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
remaining -= TCPOLEN_SACKPERM_ALIGNED;
}
+ if (fastopen && fastopen->cookie.len >= 0) {
+ u32 need = TCPOLEN_EXP_FASTOPEN_BASE + fastopen->cookie.len;
+ 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;
+ }
+ }
/* Note that timestamps are required by the specification.
*
* Odd numbers of bytes are prohibited by the specification, ensuring
@@ -2824,6 +2835,96 @@ void tcp_connect_init(struct sock *sk)
tcp_clear_retrans(tp);
}
+static void tcp_connect_queue_skb(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+
+ tcb->end_seq += skb->len;
+ skb_header_release(skb);
+ __tcp_add_write_queue_tail(sk, skb);
+ sk->sk_wmem_queued += skb->truesize;
+ sk_mem_charge(sk, skb->truesize);
+ tp->write_seq = tcb->end_seq;
+ tp->packets_out += tcp_skb_pcount(skb);
+}
+
+/* Build and send a SYN with data and (cached) Fast Open cookie. However,
+ * queue a data-only packet after the regular SYN, such that regular SYNs
+ * are retransmitted on timeouts. Also if the remote SYN-ACK acknowledges
+ * only the SYN sequence, the data are retransmitted in the first ACK.
+ * If cookie is not cached or other error occurs, falls back to send a
+ * regular SYN with Fast Open cookie request option.
+ */
+static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_fastopen_request *fo = tp->fastopen_req;
+ int space, i, err = 0, iovlen = fo->data->msg_iovlen;
+ struct sk_buff *syn_data = NULL, *data;
+
+ tcp_fastopen_cache_get(sk, &tp->rx_opt.mss_clamp, &fo->cookie);
+ if (fo->cookie.len <= 0)
+ goto fallback;
+
+ /* MSS for SYN-data is based on cached MSS and bounded by PMTU and
+ * user-MSS. Reserve maximum option space for middleboxes that add
+ * private TCP options. The cost is reduced data space in SYN :(
+ */
+ if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < tp->rx_opt.mss_clamp)
+ tp->rx_opt.mss_clamp = tp->rx_opt.user_mss;
+ space = tcp_mtu_to_mss(sk, inet_csk(sk)->icsk_pmtu_cookie) -
+ MAX_TCP_OPTION_SPACE;
+
+ syn_data = skb_copy_expand(syn, skb_headroom(syn), space,
+ sk->sk_allocation);
+ if (syn_data == NULL)
+ goto fallback;
+
+ for (i = 0; i < iovlen && syn_data->len < space; ++i) {
+ struct iovec *iov = &fo->data->msg_iov[i];
+ unsigned char __user *from = iov->iov_base;
+ int len = iov->iov_len;
+
+ if (syn_data->len + len > space)
+ len = space - syn_data->len;
+ else if (i + 1 == iovlen)
+ /* No more data pending in inet_wait_for_connect() */
+ fo->data = NULL;
+
+ if (skb_add_data(syn_data, from, len))
+ goto fallback;
+ }
+
+ /* Queue a data-only packet after the regular SYN for retransmission */
+ data = pskb_copy(syn_data, sk->sk_allocation);
+ if (data == NULL)
+ goto fallback;
+ TCP_SKB_CB(data)->seq++;
+ TCP_SKB_CB(data)->tcp_flags &= ~TCPHDR_SYN;
+ TCP_SKB_CB(data)->tcp_flags = (TCPHDR_ACK|TCPHDR_PSH);
+ tcp_connect_queue_skb(sk, data);
+ fo->copied = data->len;
+
+ if (tcp_transmit_skb(sk, syn_data, 0, sk->sk_allocation) == 0) {
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVE);
+ goto done;
+ }
+ syn_data = NULL;
+
+fallback:
+ /* Send a regular SYN with Fast Open cookie request option */
+ if (fo->cookie.len > 0)
+ fo->cookie.len = 0;
+ err = tcp_transmit_skb(sk, syn, 1, sk->sk_allocation);
+ if (err)
+ tp->syn_fastopen = 0;
+ kfree_skb(syn_data);
+done:
+ fo->cookie.len = -1; /* Exclude Fast Open option for SYN retries */
+ return err;
+}
+
/* Build a SYN and send it off. */
int tcp_connect(struct sock *sk)
{
@@ -2841,17 +2942,13 @@ int tcp_connect(struct sock *sk)
skb_reserve(buff, MAX_TCP_HEADER);
tcp_init_nondata_skb(buff, tp->write_seq++, TCPHDR_SYN);
+ tp->retrans_stamp = TCP_SKB_CB(buff)->when = tcp_time_stamp;
+ tcp_connect_queue_skb(sk, buff);
TCP_ECN_send_syn(sk, buff);
- /* Send it off. */
- TCP_SKB_CB(buff)->when = tcp_time_stamp;
- tp->retrans_stamp = TCP_SKB_CB(buff)->when;
- skb_header_release(buff);
- __tcp_add_write_queue_tail(sk, buff);
- sk->sk_wmem_queued += buff->truesize;
- sk_mem_charge(sk, buff->truesize);
- tp->packets_out += tcp_skb_pcount(buff);
- err = tcp_transmit_skb(sk, buff, 1, sk->sk_allocation);
+ /* Send off SYN; include data in Fast Open. */
+ err = tp->fastopen_req ? tcp_send_syn_data(sk, buff) :
+ tcp_transmit_skb(sk, buff, 1, sk->sk_allocation);
if (err == -ECONNREFUSED)
return err;
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-06-23 12:43:33 +0200