Merge branch 'tcp_fastopen_server'

Jerry Chu says:

====================
This patch series provides the server (passive open) side code
for TCP Fast Open. Together with the earlier client side patches
it completes the TCP Fast Open implementation.

The server side Fast Open code accepts data carried in the SYN
packet with a valid Fast Open cookie, and passes it to the
application right away, allowing application to send back response
data, all before TCP's 3-way handshake finishes.

A simple cookie scheme together with capping the number of
outstanding TFO requests (still in TCP_SYN_RECV state) to a limit
per listener forms the main line of defense against spoofed SYN
attacks.

For more details about TCP Fast Open see our IETF internet draft
at http://www.ietf.org/id/draft-ietf-tcpm-fastopen-01.txt
and a research paper at
http://conferences.sigcomm.org/co-next/2011/papers/1569470463.pdf

A prototype implementation was first developed by Sivasankar
Radhakrishnan (sivasankar@cs.ucsd.edu).

A patch based on an older version of Linux kernel has been
undergoing internal tests at Google for the past few months.

Jerry Chu (3):
  tcp: TCP Fast Open Server - header & support functions
  tcp: TCP Fast Open Server - support TFO listeners
  tcp: TCP Fast Open Server - main code path
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 43 insertions, 9 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0fca06f16463..1421b02a7905 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -224,8 +224,24 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 
 /* Bit Flags for sysctl_tcp_fastopen */
 #define	TFO_CLIENT_ENABLE	1
+#define	TFO_SERVER_ENABLE	2
 #define	TFO_CLIENT_NO_COOKIE	4	/* Data in SYN w/o cookie option */
 
+/* Process SYN data but skip cookie validation */
+#define	TFO_SERVER_COOKIE_NOT_CHKED	0x100
+/* Accept SYN data w/o any cookie option */
+#define	TFO_SERVER_COOKIE_NOT_REQD	0x200
+
+/* Force enable TFO on all listeners, i.e., not requiring the
+ * TCP_FASTOPEN socket option. SOCKOPT1/2 determine how to set max_qlen.
+ */
+#define	TFO_SERVER_WO_SOCKOPT1	0x400
+#define	TFO_SERVER_WO_SOCKOPT2	0x800
+/* Always create TFO child sockets on a TFO listener even when
+ * cookie/data not present. (For testing purpose!)
+ */
+#define	TFO_SERVER_ALWAYS	0x1000
+
 extern struct inet_timewait_death_row tcp_death_row;
 
 /* sysctl variables for tcp */
@@ -408,7 +424,8 @@ extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *
 						     const struct tcphdr *th);
 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
 				   struct request_sock *req,
-				   struct request_sock **prev);
+				   struct request_sock **prev,
+				   bool fastopen);
 extern int tcp_child_process(struct sock *parent, struct sock *child,
 			     struct sk_buff *skb);
 extern bool tcp_use_frto(struct sock *sk);
@@ -421,12 +438,6 @@ extern void tcp_metrics_init(void);
 extern bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check);
 extern bool tcp_remember_stamp(struct sock *sk);
 extern bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw);
-extern void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
-				   struct tcp_fastopen_cookie *cookie,
-				   int *syn_loss, unsigned long *last_syn_loss);
-extern void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
-				   struct tcp_fastopen_cookie *cookie,
-				   bool syn_lost);
 extern void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst);
 extern void tcp_disable_fack(struct tcp_sock *tp);
 extern void tcp_close(struct sock *sk, long timeout);
@@ -468,7 +479,8 @@ extern int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
 extern int tcp_connect(struct sock *sk);
 extern struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 					struct request_sock *req,
-					struct request_values *rvp);
+					struct request_values *rvp,
+					struct tcp_fastopen_cookie *foc);
 extern int tcp_disconnect(struct sock *sk, int flags);
 
 void tcp_connect_init(struct sock *sk);
@@ -537,6 +549,7 @@ extern void tcp_send_delayed_ack(struct sock *sk);
 extern void tcp_cwnd_application_limited(struct sock *sk);
 extern void tcp_resume_early_retransmit(struct sock *sk);
 extern void tcp_rearm_rto(struct sock *sk);
+extern void tcp_reset(struct sock *sk);
 
 /* tcp_timer.c */
 extern void tcp_init_xmit_timers(struct sock *);
@@ -586,6 +599,7 @@ extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
 extern void tcp_mtup_init(struct sock *sk);
 extern void tcp_valid_rtt_meas(struct sock *sk, u32 seq_rtt);
+extern void tcp_init_buffer_space(struct sock *sk);
 
 static inline void tcp_bound_rto(const struct sock *sk)
 {
@@ -1104,6 +1118,7 @@ static inline void tcp_openreq_init(struct request_sock *req,
 	req->rcv_wnd = 0;		/* So that tcp_send_synack() knows! */
 	req->cookie_ts = 0;
 	tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
+	tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
 	req->mss = rx_opt->mss_clamp;
 	req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
 	ireq->tstamp_ok = rx_opt->tstamp_ok;
@@ -1308,15 +1323,34 @@ 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);
 
+/* From tcp_fastopen.c */
+extern void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
+				   struct tcp_fastopen_cookie *cookie,
+				   int *syn_loss, unsigned long *last_syn_loss);
+extern void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
+				   struct tcp_fastopen_cookie *cookie,
+				   bool syn_lost);
 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);
 
+extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
+int tcp_fastopen_reset_cipher(void *key, unsigned int len);
+void tcp_fastopen_cookie_gen(__be32 addr, struct tcp_fastopen_cookie *foc);
+
+#define TCP_FASTOPEN_KEY_LENGTH 16
+
+/* Fastopen key context */
+struct tcp_fastopen_context {
+	struct crypto_cipher __rcu	*tfm;
+	__u8				key[TCP_FASTOPEN_KEY_LENGTH];
+	struct rcu_head			rcu;
+};
+
 /* write queue abstraction */
 static inline void tcp_write_queue_purge(struct sock *sk)
 {