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authorStephen Hemminger <shemminger@linux-foundation.org>2007-07-26 02:50:28 -0400
committerDavid S. Miller <davem@sunset.davemloft.net>2007-07-31 05:27:59 -0400
commit113bbbd8d2da61b50417a1dd06d8e7c19047e54b (patch)
treea120314c2a7b648d1a2b04788f6d0de37d20b974 /net/ipv4/tcp_htcp.c
parente7d0c88586a66cf03e70750a8119d984fdedf2aa (diff)
[TCP]: htcp - use measured rtt
Change HTCP to use measured RTT rather than smooth RTT. Srtt is computed using the TCP receive timestamp options, so it is vulnerable to hostile receivers. To avoid any problems this might cause use the measured RTT instead. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_htcp.c')
-rw-r--r--net/ipv4/tcp_htcp.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
index fa61663ace3..b66556c0a5b 100644
--- a/net/ipv4/tcp_htcp.c
+++ b/net/ipv4/tcp_htcp.c
@@ -76,12 +76,11 @@ static u32 htcp_cwnd_undo(struct sock *sk)
76 return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta); 76 return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta);
77} 77}
78 78
79static inline void measure_rtt(struct sock *sk) 79static inline void measure_rtt(struct sock *sk, u32 srtt)
80{ 80{
81 const struct inet_connection_sock *icsk = inet_csk(sk); 81 const struct inet_connection_sock *icsk = inet_csk(sk);
82 const struct tcp_sock *tp = tcp_sk(sk); 82 const struct tcp_sock *tp = tcp_sk(sk);
83 struct htcp *ca = inet_csk_ca(sk); 83 struct htcp *ca = inet_csk_ca(sk);
84 u32 srtt = tp->srtt >> 3;
85 84
86 /* keep track of minimum RTT seen so far, minRTT is zero at first */ 85 /* keep track of minimum RTT seen so far, minRTT is zero at first */
87 if (ca->minRTT > srtt || !ca->minRTT) 86 if (ca->minRTT > srtt || !ca->minRTT)
@@ -108,6 +107,9 @@ static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked, s32 rtt
108 if (icsk->icsk_ca_state == TCP_CA_Open) 107 if (icsk->icsk_ca_state == TCP_CA_Open)
109 ca->pkts_acked = pkts_acked; 108 ca->pkts_acked = pkts_acked;
110 109
110 if (rtt > 0)
111 measure_rtt(sk, usecs_to_jiffies(rtt));
112
111 if (!use_bandwidth_switch) 113 if (!use_bandwidth_switch)
112 return; 114 return;
113 115
@@ -237,8 +239,6 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack,
237 if (tp->snd_cwnd <= tp->snd_ssthresh) 239 if (tp->snd_cwnd <= tp->snd_ssthresh)
238 tcp_slow_start(tp); 240 tcp_slow_start(tp);
239 else { 241 else {
240 measure_rtt(sk);
241
242 /* In dangerous area, increase slowly. 242 /* In dangerous area, increase slowly.
243 * In theory this is tp->snd_cwnd += alpha / tp->snd_cwnd 243 * In theory this is tp->snd_cwnd += alpha / tp->snd_cwnd
244 */ 244 */