diff options
| -rw-r--r-- | include/linux/snmp.h | 1 | ||||
| -rw-r--r-- | include/linux/tcp.h | 6 | ||||
| -rw-r--r-- | include/net/tcp.h | 9 | ||||
| -rw-r--r-- | net/ipv4/af_inet.c | 10 | ||||
| -rw-r--r-- | net/ipv4/proc.c | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 115 |
6 files changed, 130 insertions, 12 deletions
diff --git a/include/linux/snmp.h b/include/linux/snmp.h index e5fcbd0..00bc189 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 12948f5..1edf96a 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 e601da1..867557b 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 07a02f6..edc4146 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 2a5240b..957acd1 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 4849be7..8869328 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; |
