From 5d424d5a674f782d0659a3b66d951f412901faee Mon Sep 17 00:00:00 2001 From: John Heffner Date: Mon, 20 Mar 2006 17:53:41 -0800 Subject: [TCP]: MTU probing Implementation of packetization layer path mtu discovery for TCP, based on the internet-draft currently found at . Signed-off-by: John Heffner Signed-off-by: David S. Miller --- include/linux/sysctl.h | 2 ++ include/net/inet_connection_sock.h | 13 +++++++++++++ include/net/tcp.h | 9 +++++++++ 3 files changed, 24 insertions(+) (limited to 'include') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 8ad4beab2888..6e8880ea49e7 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -397,6 +397,8 @@ enum NET_TCP_CONG_CONTROL=110, NET_TCP_ABC=111, NET_IPV4_IPFRAG_MAX_DIST=112, + NET_TCP_MTU_PROBING=113, + NET_TCP_BASE_MSS=114, }; enum { diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index fa587c94e9d0..b3abe33f4e5f 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -72,6 +72,7 @@ struct inet_connection_sock_af_ops { * @icsk_probes_out: unanswered 0 window probes * @icsk_ext_hdr_len: Network protocol overhead (IP/IPv6 options) * @icsk_ack: Delayed ACK control data + * @icsk_mtup; MTU probing control data */ struct inet_connection_sock { /* inet_sock has to be the first member! */ @@ -104,6 +105,18 @@ struct inet_connection_sock { __u16 last_seg_size; /* Size of last incoming segment */ __u16 rcv_mss; /* MSS used for delayed ACK decisions */ } icsk_ack; + struct { + int enabled; + + /* Range of MTUs to search */ + int search_high; + int search_low; + + /* Information on the current probe. */ + int probe_size; + __u32 probe_seq_start; + __u32 probe_seq_end; + } icsk_mtup; u32 icsk_ca_priv[16]; #define ICSK_CA_PRIV_SIZE (16 * sizeof(u32)) }; diff --git a/include/net/tcp.h b/include/net/tcp.h index 77f21c65bbca..16879fa560de 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -60,6 +60,9 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo); /* Minimal RCV_MSS. */ #define TCP_MIN_RCVMSS 536U +/* The least MTU to use for probing */ +#define TCP_BASE_MSS 512 + /* After receiving this amount of duplicate ACKs fast retransmit starts. */ #define TCP_FASTRETRANS_THRESH 3 @@ -219,6 +222,8 @@ extern int sysctl_tcp_nometrics_save; extern int sysctl_tcp_moderate_rcvbuf; extern int sysctl_tcp_tso_win_divisor; extern int sysctl_tcp_abc; +extern int sysctl_tcp_mtu_probing; +extern int sysctl_tcp_base_mss; extern atomic_t tcp_memory_allocated; extern atomic_t tcp_sockets_allocated; @@ -447,6 +452,10 @@ extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, extern void tcp_initialize_rcv_mss(struct sock *sk); +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); + static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) { tp->pred_flags = htonl((tp->tcp_header_len << 26) | -- cgit v1.2.3