tcp: send packets with a socket timestamp

A socket timestamp is a sum of the global tcp_time_stamp and
a per-socket offset.

A socket offset is added in places where externally visible
tcp timestamp option is parsed/initialized.

Connections in the SYN_RECV state are not supported, global
tcp_time_stamp is used for them, because repair mode doesn't support
this state. In a future it can be implemented by the similar way
as for TIME_WAIT sockets.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ea678b6..d9bfaea 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3860,7 +3860,7 @@ static bool tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr
                ++ptr;
                tp->rx_opt.rcv_tsval = ntohl(*ptr);
                ++ptr;
-               tp->rx_opt.rcv_tsecr = ntohl(*ptr);
+               tp->rx_opt.rcv_tsecr = ntohl(*ptr) - tp->tsoffset;
                return true;
        }
        return false;
@@ -3884,7 +3884,11 @@ static bool tcp_fast_parse_options(const struct sk_buff *skb,
                if (tcp_parse_aligned_timestamp(tp, th))
                        return true;
        }
+
        tcp_parse_options(skb, &tp->rx_opt, hvpp, 1, NULL);
+       if (tp->rx_opt.saw_tstamp)
+               tp->rx_opt.rcv_tsecr -= tp->tsoffset;
+
        return true;
 }
 
@@ -5665,6 +5669,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
        int saved_clamp = tp->rx_opt.mss_clamp;
 
        tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, &foc);
+       if (tp->rx_opt.saw_tstamp)
+               tp->rx_opt.rcv_tsecr -= tp->tsoffset;
 
        if (th->ack) {
                /* rfc793:

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0eaf685..77f5050 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -726,7 +726,7 @@ release_sk1:
  */
 
 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
-                           u32 win, u32 ts, int oif,
+                           u32 win, u32 tsval, u32 tsecr, int oif,
                            struct tcp_md5sig_key *key,
                            int reply_flags, u8 tos)
 {
@@ -747,12 +747,12 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
 
        arg.iov[0].iov_base = (unsigned char *)&rep;
        arg.iov[0].iov_len  = sizeof(rep.th);
-       if (ts) {
+       if (tsecr) {
                rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
                                   (TCPOPT_TIMESTAMP << 8) |
                                   TCPOLEN_TIMESTAMP);
-               rep.opt[1] = htonl(tcp_time_stamp);
-               rep.opt[2] = htonl(ts);
+               rep.opt[1] = htonl(tsval);
+               rep.opt[2] = htonl(tsecr);
                arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
        }
 
@@ -767,7 +767,7 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
 
 #ifdef CONFIG_TCP_MD5SIG
        if (key) {
-               int offset = (ts) ? 3 : 0;
+               int offset = (tsecr) ? 3 : 0;
 
                rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
                                          (TCPOPT_NOP << 16) |
@@ -802,6 +802,7 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
 
        tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
+                       tcp_time_stamp + tcptw->tw_ts_offset,
                        tcptw->tw_ts_recent,
                        tw->tw_bound_dev_if,
                        tcp_twsk_md5_key(tcptw),
@@ -821,6 +822,7 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
        tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
                        tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
                        tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
+                       tcp_time_stamp,
                        req->ts_recent,
                        0,
                        tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 4dfc99f..b83a49c 100644 (file)
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -102,6 +102,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
                tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
 
                if (tmp_opt.saw_tstamp) {
+                       tmp_opt.rcv_tsecr       -= tcptw->tw_ts_offset;
                        tmp_opt.ts_recent       = tcptw->tw_ts_recent;
                        tmp_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
                        paws_reject = tcp_paws_reject(&tmp_opt, th->rst);

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 367e2ec..564bf89 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -622,7 +622,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 
        if (likely(sysctl_tcp_timestamps && *md5 == NULL)) {
                opts->options |= OPTION_TS;
-               opts->tsval = TCP_SKB_CB(skb)->when;
+               opts->tsval = TCP_SKB_CB(skb)->when + tp->tsoffset;
                opts->tsecr = tp->rx_opt.ts_recent;
                remaining -= TCPOLEN_TSTAMP_ALIGNED;
        }
@@ -806,7 +806,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 
        if (likely(tp->rx_opt.tstamp_ok)) {
                opts->options |= OPTION_TS;
-               opts->tsval = tcb ? tcb->when : 0;
+               opts->tsval = tcb ? tcb->when + tp->tsoffset : 0;
                opts->tsecr = tp->rx_opt.ts_recent;
                size += TCPOLEN_TSTAMP_ALIGNED;
        }

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index bbb28ae..9b64600 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -713,7 +713,8 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 #endif
 
 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
-                                u32 ts, struct tcp_md5sig_key *key, int rst, u8 tclass)
+                                u32 tsval, u32 tsecr,
+                                struct tcp_md5sig_key *key, int rst, u8 tclass)
 {
        const struct tcphdr *th = tcp_hdr(skb);
        struct tcphdr *t1;
@@ -725,7 +726,7 @@ static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
        struct dst_entry *dst;
        __be32 *topt;
 
-       if (ts)
+       if (tsecr)
                tot_len += TCPOLEN_TSTAMP_ALIGNED;
 #ifdef CONFIG_TCP_MD5SIG
        if (key)
@@ -755,11 +756,11 @@ static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
 
        topt = (__be32 *)(t1 + 1);
 
-       if (ts) {
+       if (tsecr) {
                *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
                                (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
-               *topt++ = htonl(tcp_time_stamp);
-               *topt++ = htonl(ts);
+               *topt++ = htonl(tsval);
+               *topt++ = htonl(tsecr);
        }
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -860,7 +861,7 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
                ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
                          (th->doff << 2);
 
-       tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
+       tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, key, 1, 0);
 
 #ifdef CONFIG_TCP_MD5SIG
 release_sk1:
@@ -871,10 +872,11 @@ release_sk1:
 #endif
 }
 
-static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
+static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
+                           u32 win, u32 tsval, u32 tsecr,
                            struct tcp_md5sig_key *key, u8 tclass)
 {
-       tcp_v6_send_response(skb, seq, ack, win, ts, key, 0, tclass);
+       tcp_v6_send_response(skb, seq, ack, win, tsval, tsecr, key, 0, tclass);
 }
 
 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
@@ -884,6 +886,7 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 
        tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
+                       tcp_time_stamp + tcptw->tw_ts_offset,
                        tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
                        tw->tw_tclass);
 
@@ -893,7 +896,8 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
                                  struct request_sock *req)
 {
-       tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
+       tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1,
+                       req->rcv_wnd, tcp_time_stamp, req->ts_recent,
                        tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
 }