linux/net/ipv4/tcp_metrics.c

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#include <linux/rcupdate.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/cache.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/tcp.h>
#include <linux/hash.h>
#include <linux/tcp_metrics.h>
#include <linux/vmalloc.h>
#include <net/inet_connection_sock.h>
#include <net/net_namespace.h>
#include <net/request_sock.h>
#include <net/inetpeer.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/dst.h>
#include <net/tcp.h>
#include <net/genetlink.h>
int sysctl_tcp_nometrics_save __read_mostly;
static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
const struct inetpeer_addr *daddr,
struct net *net, unsigned int hash);
struct tcp_fastopen_metrics {
u16 mss;
u16 syn_loss:10, /* Recurring Fast Open SYN losses */
try_exp:2; /* Request w/ exp. option (once) */
unsigned long last_syn_loss; /* Last Fast Open SYN loss */
struct tcp_fastopen_cookie cookie;
};
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
/* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility
* Kernel only stores RTT and RTTVAR in usec resolution
*/
#define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2)
struct tcp_metrics_block {
struct tcp_metrics_block __rcu *tcpm_next;
possible_net_t tcpm_net;
struct inetpeer_addr tcpm_saddr;
struct inetpeer_addr tcpm_daddr;
unsigned long tcpm_stamp;
u32 tcpm_ts;
u32 tcpm_ts_stamp;
u32 tcpm_lock;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1];
struct tcp_fastopen_metrics tcpm_fastopen;
struct rcu_head rcu_head;
};
static inline struct net *tm_net(struct tcp_metrics_block *tm)
{
return read_pnet(&tm->tcpm_net);
}
static bool tcp_metric_locked(struct tcp_metrics_block *tm,
enum tcp_metric_index idx)
{
return tm->tcpm_lock & (1 << idx);
}
static u32 tcp_metric_get(struct tcp_metrics_block *tm,
enum tcp_metric_index idx)
{
return tm->tcpm_vals[idx];
}
static void tcp_metric_set(struct tcp_metrics_block *tm,
enum tcp_metric_index idx,
u32 val)
{
tm->tcpm_vals[idx] = val;
}
static bool addr_same(const struct inetpeer_addr *a,
const struct inetpeer_addr *b)
{
return inetpeer_addr_cmp(a, b) == 0;
}
struct tcpm_hash_bucket {
struct tcp_metrics_block __rcu *chain;
};
static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly;
static unsigned int tcp_metrics_hash_log __read_mostly;
static DEFINE_SPINLOCK(tcp_metrics_lock);
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
static void tcpm_suck_dst(struct tcp_metrics_block *tm,
const struct dst_entry *dst,
bool fastopen_clear)
{
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
u32 msval;
u32 val;
tm->tcpm_stamp = jiffies;
val = 0;
if (dst_metric_locked(dst, RTAX_RTT))
val |= 1 << TCP_METRIC_RTT;
if (dst_metric_locked(dst, RTAX_RTTVAR))
val |= 1 << TCP_METRIC_RTTVAR;
if (dst_metric_locked(dst, RTAX_SSTHRESH))
val |= 1 << TCP_METRIC_SSTHRESH;
if (dst_metric_locked(dst, RTAX_CWND))
val |= 1 << TCP_METRIC_CWND;
if (dst_metric_locked(dst, RTAX_REORDERING))
val |= 1 << TCP_METRIC_REORDERING;
tm->tcpm_lock = val;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
msval = dst_metric_raw(dst, RTAX_RTT);
tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC;
msval = dst_metric_raw(dst, RTAX_RTTVAR);
tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC;
tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);
tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);
tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);
tm->tcpm_ts = 0;
tm->tcpm_ts_stamp = 0;
if (fastopen_clear) {
tm->tcpm_fastopen.mss = 0;
tm->tcpm_fastopen.syn_loss = 0;
tm->tcpm_fastopen.try_exp = 0;
tm->tcpm_fastopen.cookie.exp = false;
tm->tcpm_fastopen.cookie.len = 0;
}
}
#define TCP_METRICS_TIMEOUT (60 * 60 * HZ)
static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst)
{
if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT)))
tcpm_suck_dst(tm, dst, false);
}
#define TCP_METRICS_RECLAIM_DEPTH 5
#define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL
#define deref_locked(p) \
rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock))
static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
struct inetpeer_addr *saddr,
struct inetpeer_addr *daddr,
unsigned int hash)
{
struct tcp_metrics_block *tm;
struct net *net;
bool reclaim = false;
spin_lock_bh(&tcp_metrics_lock);
net = dev_net(dst->dev);
/* While waiting for the spin-lock the cache might have been populated
* with this entry and so we have to check again.
*/
tm = __tcp_get_metrics(saddr, daddr, net, hash);
if (tm == TCP_METRICS_RECLAIM_PTR) {
reclaim = true;
tm = NULL;
}
if (tm) {
tcpm_check_stamp(tm, dst);
goto out_unlock;
}
if (unlikely(reclaim)) {
struct tcp_metrics_block *oldest;
oldest = deref_locked(tcp_metrics_hash[hash].chain);
for (tm = deref_locked(oldest->tcpm_next); tm;
tm = deref_locked(tm->tcpm_next)) {
if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))
oldest = tm;
}
tm = oldest;
} else {
tm = kmalloc(sizeof(*tm), GFP_ATOMIC);
if (!tm)
goto out_unlock;
}
write_pnet(&tm->tcpm_net, net);
tm->tcpm_saddr = *saddr;
tm->tcpm_daddr = *daddr;
tcpm_suck_dst(tm, dst, true);
if (likely(!reclaim)) {
tm->tcpm_next = tcp_metrics_hash[hash].chain;
rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm);
}
out_unlock:
spin_unlock_bh(&tcp_metrics_lock);
return tm;
}
static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth)
{
if (tm)
return tm;
if (depth > TCP_METRICS_RECLAIM_DEPTH)
return TCP_METRICS_RECLAIM_PTR;
return NULL;
}
static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
const struct inetpeer_addr *daddr,
struct net *net, unsigned int hash)
{
struct tcp_metrics_block *tm;
int depth = 0;
for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
tm = rcu_dereference(tm->tcpm_next)) {
if (addr_same(&tm->tcpm_saddr, saddr) &&
addr_same(&tm->tcpm_daddr, daddr) &&
net_eq(tm_net(tm), net))
break;
depth++;
}
return tcp_get_encode(tm, depth);
}
static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
struct dst_entry *dst)
{
struct tcp_metrics_block *tm;
struct inetpeer_addr saddr, daddr;
unsigned int hash;
struct net *net;
saddr.family = req->rsk_ops->family;
daddr.family = req->rsk_ops->family;
switch (daddr.family) {
case AF_INET:
inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr);
inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr);
hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr);
break;
#if IS_ENABLED(CONFIG_IPV6)
case AF_INET6:
inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr);
inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr);
hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr);
break;
#endif
default:
return NULL;
}
net = dev_net(dst->dev);
hash ^= net_hash_mix(net);
hash = hash_32(hash, tcp_metrics_hash_log);
for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
tm = rcu_dereference(tm->tcpm_next)) {
if (addr_same(&tm->tcpm_saddr, &saddr) &&
addr_same(&tm->tcpm_daddr, &daddr) &&
net_eq(tm_net(tm), net))
break;
}
tcpm_check_stamp(tm, dst);
return tm;
}
static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw)
{
struct tcp_metrics_block *tm;
struct inetpeer_addr saddr, daddr;
unsigned int hash;
struct net *net;
if (tw->tw_family == AF_INET) {
inetpeer_set_addr_v4(&saddr, tw->tw_rcv_saddr);
inetpeer_set_addr_v4(&daddr, tw->tw_daddr);
hash = ipv4_addr_hash(tw->tw_daddr);
}
#if IS_ENABLED(CONFIG_IPV6)
else if (tw->tw_family == AF_INET6) {
if (ipv6_addr_v4mapped(&tw->tw_v6_daddr)) {
inetpeer_set_addr_v4(&saddr, tw->tw_rcv_saddr);
inetpeer_set_addr_v4(&daddr, tw->tw_daddr);
hash = ipv4_addr_hash(tw->tw_daddr);
} else {
inetpeer_set_addr_v6(&saddr, &tw->tw_v6_rcv_saddr);
inetpeer_set_addr_v6(&daddr, &tw->tw_v6_daddr);
hash = ipv6_addr_hash(&tw->tw_v6_daddr);
}
}
#endif
else
return NULL;
net = twsk_net(tw);
hash ^= net_hash_mix(net);
hash = hash_32(hash, tcp_metrics_hash_log);
for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
tm = rcu_dereference(tm->tcpm_next)) {
if (addr_same(&tm->tcpm_saddr, &saddr) &&
addr_same(&tm->tcpm_daddr, &daddr) &&
net_eq(tm_net(tm), net))
break;
}
return tm;
}
static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
struct dst_entry *dst,
bool create)
{
struct tcp_metrics_block *tm;
struct inetpeer_addr saddr, daddr;
unsigned int hash;
struct net *net;
if (sk->sk_family == AF_INET) {
inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr);
inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr);
hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr);
}
#if IS_ENABLED(CONFIG_IPV6)
else if (sk->sk_family == AF_INET6) {
if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr);
inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr);
hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr);
} else {
inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr);
inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr);
hash = ipv6_addr_hash(&sk->sk_v6_daddr);
}
}
#endif
else
return NULL;
net = dev_net(dst->dev);
hash ^= net_hash_mix(net);
hash = hash_32(hash, tcp_metrics_hash_log);
tm = __tcp_get_metrics(&saddr, &daddr, net, hash);
if (tm == TCP_METRICS_RECLAIM_PTR)
tm = NULL;
if (!tm && create)
tm = tcpm_new(dst, &saddr, &daddr, hash);
else
tcpm_check_stamp(tm, dst);
return tm;
}
/* Save metrics learned by this TCP session. This function is called
* only, when TCP finishes successfully i.e. when it enters TIME-WAIT
* or goes from LAST-ACK to CLOSE.
*/
void tcp_update_metrics(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct dst_entry *dst = __sk_dst_get(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_metrics_block *tm;
unsigned long rtt;
u32 val;
int m;
if (sysctl_tcp_nometrics_save || !dst)
return;
if (dst->flags & DST_HOST)
dst_confirm(dst);
rcu_read_lock();
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
if (icsk->icsk_backoff || !tp->srtt_us) {
/* This session failed to estimate rtt. Why?
* Probably, no packets returned in time. Reset our
* results.
*/
tm = tcp_get_metrics(sk, dst, false);
if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT))
tcp_metric_set(tm, TCP_METRIC_RTT, 0);
goto out_unlock;
} else
tm = tcp_get_metrics(sk, dst, true);
if (!tm)
goto out_unlock;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
rtt = tcp_metric_get(tm, TCP_METRIC_RTT);
m = rtt - tp->srtt_us;
/* If newly calculated rtt larger than stored one, store new
* one. Otherwise, use EWMA. Remember, rtt overestimation is
* always better than underestimation.
*/
if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) {
if (m <= 0)
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
rtt = tp->srtt_us;
else
rtt -= (m >> 3);
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
tcp_metric_set(tm, TCP_METRIC_RTT, rtt);
}
if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
unsigned long var;
if (m < 0)
m = -m;
/* Scale deviation to rttvar fixed point */
m >>= 1;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
if (m < tp->mdev_us)
m = tp->mdev_us;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
var = tcp_metric_get(tm, TCP_METRIC_RTTVAR);
if (m >= var)
var = m;
else
var -= (var - m) >> 2;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
tcp_metric_set(tm, TCP_METRIC_RTTVAR, var);
}
if (tcp_in_initial_slowstart(tp)) {
/* Slow start still did not finish. */
if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
if (val && (tp->snd_cwnd >> 1) > val)
tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
tp->snd_cwnd >> 1);
}
if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
val = tcp_metric_get(tm, TCP_METRIC_CWND);
if (tp->snd_cwnd > val)
tcp_metric_set(tm, TCP_METRIC_CWND,
tp->snd_cwnd);
}
} else if (!tcp_in_slow_start(tp) &&
icsk->icsk_ca_state == TCP_CA_Open) {
/* Cong. avoidance phase, cwnd is reliable. */
if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH))
tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
val = tcp_metric_get(tm, TCP_METRIC_CWND);
tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1);
}
} else {
/* Else slow start did not finish, cwnd is non-sense,
* ssthresh may be also invalid.
*/
if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
val = tcp_metric_get(tm, TCP_METRIC_CWND);
tcp_metric_set(tm, TCP_METRIC_CWND,
(val + tp->snd_ssthresh) >> 1);
}
if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
if (val && tp->snd_ssthresh > val)
tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
tp->snd_ssthresh);
}
if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) {
val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
if (val < tp->reordering &&
tp->reordering != sysctl_tcp_reordering)
tcp_metric_set(tm, TCP_METRIC_REORDERING,
tp->reordering);
}
}
tm->tcpm_stamp = jiffies;
out_unlock:
rcu_read_unlock();
}
/* Initialize metrics on socket. */
void tcp_init_metrics(struct sock *sk)
{
struct dst_entry *dst = __sk_dst_get(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_metrics_block *tm;
u32 val, crtt = 0; /* cached RTT scaled by 8 */
if (!dst)
goto reset;
dst_confirm(dst);
rcu_read_lock();
tm = tcp_get_metrics(sk, dst, true);
if (!tm) {
rcu_read_unlock();
goto reset;
}
if (tcp_metric_locked(tm, TCP_METRIC_CWND))
tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND);
val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
if (val) {
tp->snd_ssthresh = val;
if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
tp->snd_ssthresh = tp->snd_cwnd_clamp;
} else {
/* ssthresh may have been reduced unnecessarily during.
* 3WHS. Restore it back to its initial default.
*/
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
}
val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
if (val && tp->reordering != val) {
tcp_disable_fack(tp);
tcp_disable_early_retrans(tp);
tp->reordering = val;
}
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
crtt = tcp_metric_get(tm, TCP_METRIC_RTT);
rcu_read_unlock();
reset:
/* The initial RTT measurement from the SYN/SYN-ACK is not ideal
* to seed the RTO for later data packets because SYN packets are
* small. Use the per-dst cached values to seed the RTO but keep
* the RTT estimator variables intact (e.g., srtt, mdev, rttvar).
* Later the RTO will be updated immediately upon obtaining the first
* data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only
* influences the first RTO but not later RTT estimation.
*
* But if RTT is not available from the SYN (due to retransmits or
* syn cookies) or the cache, force a conservative 3secs timeout.
*
* A bit of theory. RTT is time passed after "normal" sized packet
* is sent until it is ACKed. In normal circumstances sending small
* packets force peer to delay ACKs and calculation is correct too.
* The algorithm is adaptive and, provided we follow specs, it
* NEVER underestimate RTT. BUT! If peer tries to make some clever
* tricks sort of "quick acks" for time long enough to decrease RTT
* to low value, and then abruptly stops to do it and starts to delay
* ACKs, wait for troubles.
*/
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
if (crtt > tp->srtt_us) {
/* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
crtt /= 8 * USEC_PER_MSEC;
inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
} else if (tp->srtt_us == 0) {
/* RFC6298: 5.7 We've failed to get a valid RTT sample from
* 3WHS. This is most likely due to retransmission,
* including spurious one. Reset the RTO back to 3secs
* from the more aggressive 1sec to avoid more spurious
* retransmission.
*/
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK);
tp->mdev_us = tp->mdev_max_us = tp->rttvar_us;
inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
}
/* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
* retransmitted. In light of RFC6298 more aggressive 1sec
* initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
* retransmission has occurred.
*/
if (tp->total_retrans > 1)
tp->snd_cwnd = 1;
else
tp->snd_cwnd = tcp_init_cwnd(tp, dst);
tp->snd_cwnd_stamp = tcp_time_stamp;
}
tcp: don't allow syn packets without timestamps to pass tcp_tw_recycle logic tcp_tw_recycle heavily relies on tcp timestamps to build a per-host ordering of incoming connections and teardowns without the need to hold state on a specific quadruple for TCP_TIMEWAIT_LEN, but only for the last measured RTO. To do so, we keep the last seen timestamp in a per-host indexed data structure and verify if the incoming timestamp in a connection request is strictly greater than the saved one during last connection teardown. Thus we can verify later on that no old data packets will be accepted by the new connection. During moving a socket to time-wait state we already verify if timestamps where seen on a connection. Only if that was the case we let the time-wait socket expire after the RTO, otherwise normal TCP_TIMEWAIT_LEN will be used. But we don't verify this on incoming SYN packets. If a connection teardown was less than TCP_PAWS_MSL seconds in the past we cannot guarantee to not accept data packets from an old connection if no timestamps are present. We should drop this SYN packet. This patch closes this loophole. Please note, this patch does not make tcp_tw_recycle in any way more usable but only adds another safety check: Sporadic drops of SYN packets because of reordering in the network or in the socket backlog queues can happen. Users behing NAT trying to connect to a tcp_tw_recycle enabled server can get caught in blackholes and their connection requests may regullary get dropped because hosts behind an address translator don't have synchronized tcp timestamp clocks. tcp_tw_recycle cannot work if peers don't have tcp timestamps enabled. In general, use of tcp_tw_recycle is disadvised. Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Florian Westphal <fw@strlen.de> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-14 20:06:12 +00:00
bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst,
bool paws_check, bool timestamps)
{
struct tcp_metrics_block *tm;
bool ret;
if (!dst)
return false;
rcu_read_lock();
tm = __tcp_get_metrics_req(req, dst);
if (paws_check) {
if (tm &&
(u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL &&
tcp: don't allow syn packets without timestamps to pass tcp_tw_recycle logic tcp_tw_recycle heavily relies on tcp timestamps to build a per-host ordering of incoming connections and teardowns without the need to hold state on a specific quadruple for TCP_TIMEWAIT_LEN, but only for the last measured RTO. To do so, we keep the last seen timestamp in a per-host indexed data structure and verify if the incoming timestamp in a connection request is strictly greater than the saved one during last connection teardown. Thus we can verify later on that no old data packets will be accepted by the new connection. During moving a socket to time-wait state we already verify if timestamps where seen on a connection. Only if that was the case we let the time-wait socket expire after the RTO, otherwise normal TCP_TIMEWAIT_LEN will be used. But we don't verify this on incoming SYN packets. If a connection teardown was less than TCP_PAWS_MSL seconds in the past we cannot guarantee to not accept data packets from an old connection if no timestamps are present. We should drop this SYN packet. This patch closes this loophole. Please note, this patch does not make tcp_tw_recycle in any way more usable but only adds another safety check: Sporadic drops of SYN packets because of reordering in the network or in the socket backlog queues can happen. Users behing NAT trying to connect to a tcp_tw_recycle enabled server can get caught in blackholes and their connection requests may regullary get dropped because hosts behind an address translator don't have synchronized tcp timestamp clocks. tcp_tw_recycle cannot work if peers don't have tcp timestamps enabled. In general, use of tcp_tw_recycle is disadvised. Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Florian Westphal <fw@strlen.de> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-14 20:06:12 +00:00
((s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW ||
!timestamps))
ret = false;
else
ret = true;
} else {
if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp)
ret = true;
else
ret = false;
}
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(tcp_peer_is_proven);
void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst)
{
struct tcp_metrics_block *tm;
rcu_read_lock();
tm = tcp_get_metrics(sk, dst, true);
if (tm) {
struct tcp_sock *tp = tcp_sk(sk);
if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) {
tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp;
tp->rx_opt.ts_recent = tm->tcpm_ts;
}
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp);
/* VJ's idea. Save last timestamp seen from this destination and hold
* it at least for normal timewait interval to use for duplicate
* segment detection in subsequent connections, before they enter
* synchronized state.
*/
bool tcp_remember_stamp(struct sock *sk)
{
struct dst_entry *dst = __sk_dst_get(sk);
bool ret = false;
if (dst) {
struct tcp_metrics_block *tm;
rcu_read_lock();
tm = tcp_get_metrics(sk, dst, true);
if (tm) {
struct tcp_sock *tp = tcp_sk(sk);
if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 ||
((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
tm->tcpm_ts = tp->rx_opt.ts_recent;
}
ret = true;
}
rcu_read_unlock();
}
return ret;
}
bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
{
struct tcp_metrics_block *tm;
bool ret = false;
rcu_read_lock();
tm = __tcp_get_metrics_tw(tw);
if (tm) {
const struct tcp_timewait_sock *tcptw;
struct sock *sk = (struct sock *) tw;
tcptw = tcp_twsk(sk);
if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 ||
((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
tm->tcpm_ts = tcptw->tw_ts_recent;
}
ret = true;
}
rcu_read_unlock();
return ret;
}
static DEFINE_SEQLOCK(fastopen_seqlock);
void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
struct tcp_fastopen_cookie *cookie,
int *syn_loss, unsigned long *last_syn_loss)
{
struct tcp_metrics_block *tm;
rcu_read_lock();
tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
if (tm) {
struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
unsigned int seq;
do {
seq = read_seqbegin(&fastopen_seqlock);
if (tfom->mss)
*mss = tfom->mss;
*cookie = tfom->cookie;
if (cookie->len <= 0 && tfom->try_exp == 1)
cookie->exp = true;
*syn_loss = tfom->syn_loss;
*last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
} while (read_seqretry(&fastopen_seqlock, seq));
}
rcu_read_unlock();
}
void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
struct tcp_fastopen_cookie *cookie, bool syn_lost,
u16 try_exp)
{
struct dst_entry *dst = __sk_dst_get(sk);
struct tcp_metrics_block *tm;
if (!dst)
return;
rcu_read_lock();
tm = tcp_get_metrics(sk, dst, true);
if (tm) {
struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
write_seqlock_bh(&fastopen_seqlock);
if (mss)
tfom->mss = mss;
if (cookie && cookie->len > 0)
tfom->cookie = *cookie;
else if (try_exp > tfom->try_exp &&
tfom->cookie.len <= 0 && !tfom->cookie.exp)
tfom->try_exp = try_exp;
if (syn_lost) {
++tfom->syn_loss;
tfom->last_syn_loss = jiffies;
} else
tfom->syn_loss = 0;
write_sequnlock_bh(&fastopen_seqlock);
}
rcu_read_unlock();
}
static struct genl_family tcp_metrics_nl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = TCP_METRICS_GENL_NAME,
.version = TCP_METRICS_GENL_VERSION,
.maxattr = TCP_METRICS_ATTR_MAX,
.netnsok = true,
};
static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
[TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, },
[TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY,
.len = sizeof(struct in6_addr), },
/* Following attributes are not received for GET/DEL,
* we keep them for reference
*/
#if 0
[TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, },
[TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, },
[TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, },
[TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, },
[TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, },
[TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, },
[TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, },
[TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
.len = TCP_FASTOPEN_COOKIE_MAX, },
#endif
};
/* Add attributes, caller cancels its header on failure */
static int tcp_metrics_fill_info(struct sk_buff *msg,
struct tcp_metrics_block *tm)
{
struct nlattr *nest;
int i;
switch (tm->tcpm_daddr.family) {
case AF_INET:
if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4,
inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0)
goto nla_put_failure;
if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4,
inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0)
goto nla_put_failure;
break;
case AF_INET6:
if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6,
inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0)
goto nla_put_failure;
if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6,
inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0)
goto nla_put_failure;
break;
default:
return -EAFNOSUPPORT;
}
if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
jiffies - tm->tcpm_stamp) < 0)
goto nla_put_failure;
if (tm->tcpm_ts_stamp) {
if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP,
(s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0)
goto nla_put_failure;
if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL,
tm->tcpm_ts) < 0)
goto nla_put_failure;
}
{
int n = 0;
nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
if (!nest)
goto nla_put_failure;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) {
u32 val = tm->tcpm_vals[i];
if (!val)
continue;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
if (i == TCP_METRIC_RTT) {
if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1,
val) < 0)
goto nla_put_failure;
n++;
val = max(val / 1000, 1U);
}
if (i == TCP_METRIC_RTTVAR) {
if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1,
val) < 0)
goto nla_put_failure;
n++;
val = max(val / 1000, 1U);
}
if (nla_put_u32(msg, i + 1, val) < 0)
goto nla_put_failure;
n++;
}
if (n)
nla_nest_end(msg, nest);
else
nla_nest_cancel(msg, nest);
}
{
struct tcp_fastopen_metrics tfom_copy[1], *tfom;
unsigned int seq;
do {
seq = read_seqbegin(&fastopen_seqlock);
tfom_copy[0] = tm->tcpm_fastopen;
} while (read_seqretry(&fastopen_seqlock, seq));
tfom = tfom_copy;
if (tfom->mss &&
nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
tfom->mss) < 0)
goto nla_put_failure;
if (tfom->syn_loss &&
(nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
tfom->syn_loss) < 0 ||
nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
jiffies - tfom->last_syn_loss) < 0))
goto nla_put_failure;
if (tfom->cookie.len > 0 &&
nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
tfom->cookie.len, tfom->cookie.val) < 0)
goto nla_put_failure;
}
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int tcp_metrics_dump_info(struct sk_buff *skb,
struct netlink_callback *cb,
struct tcp_metrics_block *tm)
{
void *hdr;
hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
&tcp_metrics_nl_family, NLM_F_MULTI,
TCP_METRICS_CMD_GET);
if (!hdr)
return -EMSGSIZE;
if (tcp_metrics_fill_info(skb, tm) < 0)
goto nla_put_failure;
netlink: make nlmsg_end() and genlmsg_end() void Contrary to common expectations for an "int" return, these functions return only a positive value -- if used correctly they cannot even return 0 because the message header will necessarily be in the skb. This makes the very common pattern of if (genlmsg_end(...) < 0) { ... } be a whole bunch of dead code. Many places also simply do return nlmsg_end(...); and the caller is expected to deal with it. This also commonly (at least for me) causes errors, because it is very common to write if (my_function(...)) /* error condition */ and if my_function() does "return nlmsg_end()" this is of course wrong. Additionally, there's not a single place in the kernel that actually needs the message length returned, and if anyone needs it later then it'll be very easy to just use skb->len there. Remove this, and make the functions void. This removes a bunch of dead code as described above. The patch adds lines because I did - return nlmsg_end(...); + nlmsg_end(...); + return 0; I could have preserved all the function's return values by returning skb->len, but instead I've audited all the places calling the affected functions and found that none cared. A few places actually compared the return value with <= 0 in dump functionality, but that could just be changed to < 0 with no change in behaviour, so I opted for the more efficient version. One instance of the error I've made numerous times now is also present in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't check for <0 or <=0 and thus broke out of the loop every single time. I've preserved this since it will (I think) have caused the messages to userspace to be formatted differently with just a single message for every SKB returned to userspace. It's possible that this isn't needed for the tools that actually use this, but I don't even know what they are so couldn't test that changing this behaviour would be acceptable. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-16 21:09:00 +00:00
genlmsg_end(skb, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return -EMSGSIZE;
}
static int tcp_metrics_nl_dump(struct sk_buff *skb,
struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
unsigned int max_rows = 1U << tcp_metrics_hash_log;
unsigned int row, s_row = cb->args[0];
int s_col = cb->args[1], col = s_col;
for (row = s_row; row < max_rows; row++, s_col = 0) {
struct tcp_metrics_block *tm;
struct tcpm_hash_bucket *hb = tcp_metrics_hash + row;
rcu_read_lock();
for (col = 0, tm = rcu_dereference(hb->chain); tm;
tm = rcu_dereference(tm->tcpm_next), col++) {
if (!net_eq(tm_net(tm), net))
continue;
if (col < s_col)
continue;
if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
rcu_read_unlock();
goto done;
}
}
rcu_read_unlock();
}
done:
cb->args[0] = row;
cb->args[1] = col;
return skb->len;
}
static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
unsigned int *hash, int optional, int v4, int v6)
{
struct nlattr *a;
a = info->attrs[v4];
if (a) {
inetpeer_set_addr_v4(addr, nla_get_in_addr(a));
if (hash)
*hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr));
return 0;
}
a = info->attrs[v6];
if (a) {
struct in6_addr in6;
if (nla_len(a) != sizeof(struct in6_addr))
return -EINVAL;
in6 = nla_get_in6_addr(a);
inetpeer_set_addr_v6(addr, &in6);
if (hash)
*hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr));
return 0;
}
return optional ? 1 : -EAFNOSUPPORT;
}
static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
unsigned int *hash, int optional)
{
return __parse_nl_addr(info, addr, hash, optional,
TCP_METRICS_ATTR_ADDR_IPV4,
TCP_METRICS_ATTR_ADDR_IPV6);
}
static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr)
{
return __parse_nl_addr(info, addr, NULL, 0,
TCP_METRICS_ATTR_SADDR_IPV4,
TCP_METRICS_ATTR_SADDR_IPV6);
}
static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
{
struct tcp_metrics_block *tm;
struct inetpeer_addr saddr, daddr;
unsigned int hash;
struct sk_buff *msg;
struct net *net = genl_info_net(info);
void *reply;
int ret;
bool src = true;
ret = parse_nl_addr(info, &daddr, &hash, 0);
if (ret < 0)
return ret;
ret = parse_nl_saddr(info, &saddr);
if (ret < 0)
src = false;
msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;
reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
info->genlhdr->cmd);
if (!reply)
goto nla_put_failure;
hash ^= net_hash_mix(net);
hash = hash_32(hash, tcp_metrics_hash_log);
ret = -ESRCH;
rcu_read_lock();
for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
tm = rcu_dereference(tm->tcpm_next)) {
if (addr_same(&tm->tcpm_daddr, &daddr) &&
(!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
net_eq(tm_net(tm), net)) {
ret = tcp_metrics_fill_info(msg, tm);
break;
}
}
rcu_read_unlock();
if (ret < 0)
goto out_free;
genlmsg_end(msg, reply);
return genlmsg_reply(msg, info);
nla_put_failure:
ret = -EMSGSIZE;
out_free:
nlmsg_free(msg);
return ret;
}
static void tcp_metrics_flush_all(struct net *net)
{
unsigned int max_rows = 1U << tcp_metrics_hash_log;
struct tcpm_hash_bucket *hb = tcp_metrics_hash;
struct tcp_metrics_block *tm;
unsigned int row;
for (row = 0; row < max_rows; row++, hb++) {
struct tcp_metrics_block __rcu **pp;
spin_lock_bh(&tcp_metrics_lock);
pp = &hb->chain;
for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
if (net_eq(tm_net(tm), net)) {
*pp = tm->tcpm_next;
kfree_rcu(tm, rcu_head);
} else {
pp = &tm->tcpm_next;
}
}
spin_unlock_bh(&tcp_metrics_lock);
}
}
static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
{
struct tcpm_hash_bucket *hb;
struct tcp_metrics_block *tm;
struct tcp_metrics_block __rcu **pp;
struct inetpeer_addr saddr, daddr;
unsigned int hash;
struct net *net = genl_info_net(info);
int ret;
bool src = true, found = false;
ret = parse_nl_addr(info, &daddr, &hash, 1);
if (ret < 0)
return ret;
if (ret > 0) {
tcp_metrics_flush_all(net);
return 0;
}
ret = parse_nl_saddr(info, &saddr);
if (ret < 0)
src = false;
hash ^= net_hash_mix(net);
hash = hash_32(hash, tcp_metrics_hash_log);
hb = tcp_metrics_hash + hash;
pp = &hb->chain;
spin_lock_bh(&tcp_metrics_lock);
for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
if (addr_same(&tm->tcpm_daddr, &daddr) &&
(!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
net_eq(tm_net(tm), net)) {
*pp = tm->tcpm_next;
kfree_rcu(tm, rcu_head);
found = true;
} else {
pp = &tm->tcpm_next;
}
}
spin_unlock_bh(&tcp_metrics_lock);
if (!found)
return -ESRCH;
return 0;
}
static const struct genl_ops tcp_metrics_nl_ops[] = {
{
.cmd = TCP_METRICS_CMD_GET,
.doit = tcp_metrics_nl_cmd_get,
.dumpit = tcp_metrics_nl_dump,
.policy = tcp_metrics_nl_policy,
},
{
.cmd = TCP_METRICS_CMD_DEL,
.doit = tcp_metrics_nl_cmd_del,
.policy = tcp_metrics_nl_policy,
.flags = GENL_ADMIN_PERM,
},
};
static unsigned int tcpmhash_entries;
static int __init set_tcpmhash_entries(char *str)
{
ssize_t ret;
if (!str)
return 0;
ret = kstrtouint(str, 0, &tcpmhash_entries);
if (ret)
return 0;
return 1;
}
__setup("tcpmhash_entries=", set_tcpmhash_entries);
static int __net_init tcp_net_metrics_init(struct net *net)
{
size_t size;
unsigned int slots;
if (!net_eq(net, &init_net))
return 0;
slots = tcpmhash_entries;
if (!slots) {
if (totalram_pages >= 128 * 1024)
slots = 16 * 1024;
else
slots = 8 * 1024;
}
tcp_metrics_hash_log = order_base_2(slots);
size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log;
tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
if (!tcp_metrics_hash)
tcp_metrics_hash = vzalloc(size);
if (!tcp_metrics_hash)
return -ENOMEM;
return 0;
}
static void __net_exit tcp_net_metrics_exit(struct net *net)
{
tcp_metrics_flush_all(net);
}
static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
.init = tcp_net_metrics_init,
.exit = tcp_net_metrics_exit,
};
void __init tcp_metrics_init(void)
{
int ret;
ret = register_pernet_subsys(&tcp_net_metrics_ops);
if (ret < 0)
panic("Could not allocate the tcp_metrics hash table\n");
ret = genl_register_family_with_ops(&tcp_metrics_nl_family,
tcp_metrics_nl_ops);
if (ret < 0)
panic("Could not register tcp_metrics generic netlink\n");
}