diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 45 | ||||
| -rw-r--r-- | include/net/tcp.h | 3 | ||||
| -rw-r--r-- | net/ipv4/af_inet.c | 21 |
3 files changed, 32 insertions, 37 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 9ae929395b24..3db8c67d2c8d 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -575,32 +575,33 @@ tcp_syncookies - BOOLEAN unconditionally generation of syncookies. tcp_fastopen - INTEGER - Enable TCP Fast Open feature (draft-ietf-tcpm-fastopen) to send data - in the opening SYN packet. To use this feature, the client application - must use sendmsg() or sendto() with MSG_FASTOPEN flag rather than - connect() to perform a TCP handshake automatically. + Enable TCP Fast Open (RFC7413) to send and accept data in the opening + SYN packet. - The values (bitmap) are - 1: Enables sending data in the opening SYN on the client w/ MSG_FASTOPEN. - 2: Enables TCP Fast Open on the server side, i.e., allowing data in - a SYN packet to be accepted and passed to the application before - 3-way hand shake finishes. - 4: Send data in the opening SYN regardless of cookie availability and - without a cookie option. - 0x100: Accept SYN data w/o validating the cookie. - 0x200: Accept data-in-SYN w/o any cookie option present. - 0x400/0x800: Enable Fast Open on all listeners regardless of the - TCP_FASTOPEN socket option. The two different flags designate two - different ways of setting max_qlen without the TCP_FASTOPEN socket - option. + The client support is enabled by flag 0x1 (on by default). The client + then must use sendmsg() or sendto() with the MSG_FASTOPEN flag, + rather than connect() to send data in SYN. - Default: 1 + The server support is enabled by flag 0x2 (off by default). Then + either enable for all listeners with another flag (0x400) or + enable individual listeners via TCP_FASTOPEN socket option with + the option value being the length of the syn-data backlog. - Note that the client & server side Fast Open flags (1 and 2 - respectively) must be also enabled before the rest of flags can take - effect. + The values (bitmap) are + 0x1: (client) enables sending data in the opening SYN on the client. + 0x2: (server) enables the server support, i.e., allowing data in + a SYN packet to be accepted and passed to the + application before 3-way handshake finishes. + 0x4: (client) send data in the opening SYN regardless of cookie + availability and without a cookie option. + 0x200: (server) accept data-in-SYN w/o any cookie option present. + 0x400: (server) enable all listeners to support Fast Open by + default without explicit TCP_FASTOPEN socket option. + + Default: 0x1 - See include/net/tcp.h and the code for more details. + Note that that additional client or server features are only + effective if the basic support (0x1 and 0x2) are enabled respectively. tcp_syn_retries - INTEGER Number of times initial SYNs for an active TCP connection attempt diff --git a/include/net/tcp.h b/include/net/tcp.h index c00e7d51bb18..25d64f6de69e 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -227,10 +227,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo); #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. + * TCP_FASTOPEN socket option. */ #define TFO_SERVER_WO_SOCKOPT1 0x400 -#define TFO_SERVER_WO_SOCKOPT2 0x800 extern struct inet_timewait_death_row tcp_death_row; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 55513e654d79..989a362814a9 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -211,24 +211,19 @@ int inet_listen(struct socket *sock, int backlog) * we can only allow the backlog to be adjusted. */ if (old_state != TCP_LISTEN) { - /* Check special setups for testing purpose to enable TFO w/o - * requiring TCP_FASTOPEN sockopt. + /* Enable TFO w/o requiring TCP_FASTOPEN socket option. * Note that only TCP sockets (SOCK_STREAM) will reach here. - * Also fastopenq may already been allocated because this - * socket was in TCP_LISTEN state previously but was - * shutdown() (rather than close()). + * Also fastopen backlog may already been set via the option + * because the socket was in TCP_LISTEN state previously but + * was shutdown() rather than close(). */ - if ((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) != 0 && + if ((sysctl_tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) && + (sysctl_tcp_fastopen & TFO_SERVER_ENABLE) && !inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) { - if ((sysctl_tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) != 0) - fastopen_queue_tune(sk, backlog); - else if ((sysctl_tcp_fastopen & - TFO_SERVER_WO_SOCKOPT2) != 0) - fastopen_queue_tune(sk, - ((uint)sysctl_tcp_fastopen) >> 16); - + fastopen_queue_tune(sk, backlog); tcp_fastopen_init_key_once(true); } + err = inet_csk_listen_start(sk, backlog); if (err) goto out; |