From 1046716368979dee857a2b8a91c4a8833f21b9cb Mon Sep 17 00:00:00 2001 From: Jerry Chu Date: Fri, 31 Aug 2012 12:29:11 +0000 Subject: tcp: TCP Fast Open Server - header & support functions This patch adds all the necessary data structure and support functions to implement TFO server side. It also documents a number of flags for the sysctl_tcp_fastopen knob, and adds a few Linux extension MIBs. In addition, it includes the following: 1. a new TCP_FASTOPEN socket option an application must call to supply a max backlog allowed in order to enable TFO on its listener. 2. A number of key data structures: "fastopen_rsk" in tcp_sock - for a big socket to access its request_sock for retransmission and ack processing purpose. It is non-NULL iff 3WHS not completed. "fastopenq" in request_sock_queue - points to a per Fast Open listener data structure "fastopen_queue" to keep track of qlen (# of outstanding Fast Open requests) and max_qlen, among other things. "listener" in tcp_request_sock - to point to the original listener for book-keeping purpose, i.e., to maintain qlen against max_qlen as part of defense against IP spoofing attack. 3. various data structure and functions, many in tcp_fastopen.c, to support server side Fast Open cookie operations, including /proc/sys/net/ipv4/tcp_fastopen_key to allow manual rekeying. Signed-off-by: H.K. Jerry Chu Cc: Yuchung Cheng Cc: Neal Cardwell Cc: Eric Dumazet Cc: Tom Herbert Signed-off-by: David S. Miller --- include/linux/tcp.h | 45 ++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 42 insertions(+), 3 deletions(-) (limited to 'include/linux/tcp.h') diff --git a/include/linux/tcp.h b/include/linux/tcp.h index eb125a4c30b3..ae46df590629 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -110,6 +110,7 @@ enum { #define TCP_REPAIR_QUEUE 20 #define TCP_QUEUE_SEQ 21 #define TCP_REPAIR_OPTIONS 22 +#define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */ struct tcp_repair_opt { __u32 opt_code; @@ -246,6 +247,7 @@ static inline unsigned int tcp_optlen(const struct sk_buff *skb) /* 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 */ +#define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */ /* TCP Fast Open Cookie as stored in memory */ struct tcp_fastopen_cookie { @@ -312,9 +314,14 @@ struct tcp_request_sock { /* Only used by TCP MD5 Signature so far. */ const struct tcp_request_sock_ops *af_specific; #endif + struct sock *listener; /* needed for TFO */ u32 rcv_isn; u32 snt_isn; u32 snt_synack; /* synack sent time */ + u32 rcv_nxt; /* the ack # by SYNACK. For + * FastOpen it's the seq# + * after data-in-SYN. + */ }; static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) @@ -505,14 +512,18 @@ 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. */ struct tcp_cookie_values *cookie_values; + +/* TCP fastopen related information */ + struct tcp_fastopen_request *fastopen_req; + /* fastopen_rsk points to request_sock that resulted in this big + * socket. Used to retransmit SYNACKs etc. + */ + struct request_sock *fastopen_rsk; }; enum tsq_flags { @@ -552,6 +563,34 @@ static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) return (struct tcp_timewait_sock *)sk; } +static inline bool tcp_passive_fastopen(const struct sock *sk) +{ + return (sk->sk_state == TCP_SYN_RECV && + tcp_sk(sk)->fastopen_rsk != NULL); +} + +static inline bool fastopen_cookie_present(struct tcp_fastopen_cookie *foc) +{ + return foc->len != -1; +} + +static inline int fastopen_init_queue(struct sock *sk, int backlog) +{ + struct request_sock_queue *queue = + &inet_csk(sk)->icsk_accept_queue; + + if (queue->fastopenq == NULL) { + queue->fastopenq = kzalloc( + sizeof(struct fastopen_queue), + sk->sk_allocation); + if (queue->fastopenq == NULL) + return -ENOMEM; + spin_lock_init(&queue->fastopenq->lock); + } + queue->fastopenq->max_qlen = backlog; + return 0; +} + #endif /* __KERNEL__ */ #endif /* _LINUX_TCP_H */ -- cgit v1.2.3