Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758270AbYBORjl (ORCPT ); Fri, 15 Feb 2008 12:39:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754812AbYBORjX (ORCPT ); Fri, 15 Feb 2008 12:39:23 -0500 Received: from rv-out-0910.google.com ([209.85.198.189]:25821 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753611AbYBORjW (ORCPT ); Fri, 15 Feb 2008 12:39:22 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer; b=s9+iPeWj7RXROiFr37nBR4/P0uwIANVBYM6xY1vqxPXV1fY0ktQUl/8pn6rNiBj1JZJhD3u++WexpEqWR6x4X7zMgYd7vP+9SqmgGh9TtL0jE/Jy+YR/ZNSxH+O34c5aThKLMdZMhovN/zy4+yRzoOFO/UJDZtZ8bIRHUrCXnUY= From: Glenn Griffin To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Glenn Griffin Subject: [PATCH 1/3] Support arbitrary initial TCP timestamps Date: Fri, 15 Feb 2008 09:47:08 -0800 Message-Id: <1203097630-13237-1-git-send-email-ggriffin.kernel@gmail.com> X-Mailer: git-send-email 1.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8091 Lines: 222 Introduce the ability to send arbitrary initial tcp timestamps that are not tied directly to jiffies. The basic conecpt is every tcp_request_sock and tcp_sock now has a ts_off offset that represents the difference between tcp_time_stamp and the timestamp we send and expect to receive. This has the advantage of not divulging system information (uptime) depending on the policy chosen for the initial timestamps. A policy where ts_off is always set to zero should produce no change in behavior. The policy implemented is not intended for real use, but just as a simple example. A realistic example would probably be similar to the tcp init sequence generator. Signed-off-by: Glenn Griffin --- include/linux/tcp.h | 6 ++++++ include/net/tcp.h | 2 +- net/ipv4/tcp_input.c | 12 ++++++------ net/ipv4/tcp_ipv4.c | 2 +- net/ipv4/tcp_minisocks.c | 5 +++-- net/ipv4/tcp_output.c | 8 +++++--- net/ipv6/tcp_ipv6.c | 2 +- 7 files changed, 23 insertions(+), 14 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 08027f1..68387dc 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -232,6 +232,7 @@ struct tcp_request_sock { #endif u32 rcv_isn; u32 snt_isn; + u32 ts_off; }; static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) @@ -311,6 +312,11 @@ struct tcp_sock { struct tcp_options_received rx_opt; /* + * offset of transmitted tcp timestamp from jiffies + */ + u32 ts_off; + +/* * Slow start and congestion control (see also Nagle, and Karn & Partridge) */ u32 snd_ssthresh; /* Slow start size threshold */ diff --git a/include/net/tcp.h b/include/net/tcp.h index 7de4ea3..c935de7 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -395,7 +395,7 @@ extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, extern void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx, - int estab); + int estab, u32 tsecr_off); /* * TCP v4 functions exported for the inet6 API diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 19c449f..95fa8dc 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3264,7 +3264,7 @@ uninteresting_ack: * the fast version below fails. */ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx, - int estab) + int estab, u32 tsecr_off) { unsigned char *ptr; struct tcphdr *th = tcp_hdr(skb); @@ -3322,7 +3322,7 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx, (!estab && sysctl_tcp_timestamps))) { opt_rx->saw_tstamp = 1; opt_rx->rcv_tsval = ntohl(get_unaligned((__be32 *)ptr)); - opt_rx->rcv_tsecr = ntohl(get_unaligned((__be32 *)(ptr+4))); + opt_rx->rcv_tsecr = ntohl(get_unaligned((__be32 *)(ptr+4))) - tsecr_off; } break; case TCPOPT_SACK_PERM: @@ -3374,11 +3374,11 @@ static int tcp_fast_parse_options(struct sk_buff *skb, struct tcphdr *th, ++ptr; tp->rx_opt.rcv_tsval = ntohl(*ptr); ++ptr; - tp->rx_opt.rcv_tsecr = ntohl(*ptr); + tp->rx_opt.rcv_tsecr = ntohl(*ptr) - tp->ts_off; return 1; } } - tcp_parse_options(skb, &tp->rx_opt, 1); + tcp_parse_options(skb, &tp->rx_opt, 1, tp->ts_off); return 1; } @@ -4615,7 +4615,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, ++ptr; tp->rx_opt.rcv_tsval = ntohl(*ptr); ++ptr; - tp->rx_opt.rcv_tsecr = ntohl(*ptr); + tp->rx_opt.rcv_tsecr = ntohl(*ptr) - tp->ts_off; /* If PAWS failed, check it more carefully in slow path */ if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) < 0) @@ -4824,7 +4824,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, struct inet_connection_sock *icsk = inet_csk(sk); int saved_clamp = tp->rx_opt.mss_clamp; - tcp_parse_options(skb, &tp->rx_opt, 0); + tcp_parse_options(skb, &tp->rx_opt, 0, tp->ts_off); if (th->ack) { /* rfc793: diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 63414ea..267eda9 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1295,7 +1295,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) tmp_opt.mss_clamp = 536; tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss; - tcp_parse_options(skb, &tmp_opt, 0); + tcp_parse_options(skb, &tmp_opt, 0, 0); if (want_cookie) { tcp_clear_options(&tmp_opt); diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index b61b768..648f84e 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -102,7 +102,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, tmp_opt.saw_tstamp = 0; if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) { - tcp_parse_options(skb, &tmp_opt, 0); + tcp_parse_options(skb, &tmp_opt, 0, 0); if (tmp_opt.saw_tstamp) { tmp_opt.ts_recent = tcptw->tw_ts_recent; @@ -442,6 +442,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, inet_csk_reset_keepalive_timer(newsk, keepalive_time_when(newtp)); + newtp->ts_off = treq->ts_off; newtp->rx_opt.tstamp_ok = ireq->tstamp_ok; if ((newtp->rx_opt.sack_ok = ireq->sack_ok) != 0) { if (sysctl_tcp_fack) @@ -502,7 +503,7 @@ struct sock *tcp_check_req(struct sock *sk,struct sk_buff *skb, tmp_opt.saw_tstamp = 0; if (th->doff > (sizeof(struct tcphdr)>>2)) { - tcp_parse_options(skb, &tmp_opt, 0); + tcp_parse_options(skb, &tmp_opt, 0, tcp_rsk(req)->ts_off); if (tmp_opt.saw_tstamp) { tmp_opt.ts_recent = req->ts_recent; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index ed750f9..81f1383 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -583,7 +583,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, (sysctl_flags & SYSCTL_FLAG_SACK), (sysctl_flags & SYSCTL_FLAG_WSCALE), tp->rx_opt.rcv_wscale, - tcb->when, + tcb->when + tp->ts_off, tp->rx_opt.ts_recent, #ifdef CONFIG_TCP_MD5SIG @@ -592,7 +592,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, NULL); } else { tcp_build_and_update_options((__be32 *)(th + 1), - tp, tcb->when, + tp, tcb->when + tp->ts_off, #ifdef CONFIG_TCP_MD5SIG md5 ? &md5_hash_location : #endif @@ -2227,9 +2227,10 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, th->window = htons(min(req->rcv_wnd, 65535U)); TCP_SKB_CB(skb)->when = tcp_time_stamp; + tcp_rsk(req)->ts_off = 1000 - TCP_SKB_CB(skb)->when; tcp_syn_build_options((__be32 *)(th + 1), dst_metric(dst, RTAX_ADVMSS), ireq->tstamp_ok, ireq->sack_ok, ireq->wscale_ok, ireq->rcv_wscale, - TCP_SKB_CB(skb)->when, + TCP_SKB_CB(skb)->when + tcp_rsk(req)->ts_off, req->ts_recent, ( #ifdef CONFIG_TCP_MD5SIG @@ -2335,6 +2336,7 @@ int tcp_connect(struct sock *sk) /* Send it off. */ TCP_SKB_CB(buff)->when = tcp_time_stamp; + tp->ts_off = 2000 - TCP_SKB_CB(buff)->when; tp->retrans_stamp = TCP_SKB_CB(buff)->when; skb_header_release(buff); __tcp_add_write_queue_tail(sk, buff); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 12750f2..896ebd0 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1264,7 +1264,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr); tmp_opt.user_mss = tp->rx_opt.user_mss; - tcp_parse_options(skb, &tmp_opt, 0); + tcp_parse_options(skb, &tmp_opt, 0, 0); tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; tcp_openreq_init(req, &tmp_opt, skb); -- 1.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/