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linux-next/net/ipv4/tcp_metrics.c
Yuchung Cheng 7268586baa tcp: pause Fast Open globally after third consecutive timeout
Prior to this patch, active Fast Open is paused on a specific
destination IP address if the previous connections to the
IP address have experienced recurring timeouts . But recent
experiments by Microsoft (https://goo.gl/cykmn7) and Mozilla
browsers indicate the isssue is often caused by broken middle-boxes
sitting close to the client. Therefore it is much better user
experience if Fast Open is disabled out-right globally to avoid
experiencing further timeouts on connections toward other
destinations.

This patch changes the destination-IP disablement to global
disablement if a connection experiencing recurring timeouts
or aborts due to timeout.  Repeated incidents would still
exponentially increase the pause time, starting from an hour.
This is extremely conservative but an unfortunate compromise to
minimize bad experience due to broken middle-boxes.

Reported-by: Dragana Damjanovic <ddamjanovic@mozilla.com>
Reported-by: Patrick McManus <mcmanus@ducksong.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Wei Wang <weiwan@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-13 15:51:12 -05:00

1041 lines
27 KiB
C

// SPDX-License-Identifier: GPL-2.0
#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>
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_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_lock;
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);
static void tcpm_suck_dst(struct tcp_metrics_block *tm,
const struct dst_entry *dst,
bool fastopen_clear)
{
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;
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);
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(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 net *net = sock_net(sk);
struct tcp_metrics_block *tm;
unsigned long rtt;
u32 val;
int m;
sk_dst_confirm(sk);
if (net->ipv4.sysctl_tcp_nometrics_save || !dst)
return;
rcu_read_lock();
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;
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)
rtt = tp->srtt_us;
else
rtt -= (m >> 3);
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;
if (m < tp->mdev_us)
m = tp->mdev_us;
var = tcp_metric_get(tm, TCP_METRIC_RTTVAR);
if (m >= var)
var = m;
else
var -= (var - m) >> 2;
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 != net->ipv4.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 */
sk_dst_confirm(sk);
if (!dst)
goto reset;
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)
tp->reordering = val;
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.
*/
if (crtt > tp->srtt_us) {
/* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
crtt /= 8 * USEC_PER_SEC / HZ;
inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
} 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.
*/
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_jiffies32;
}
bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)
{
struct tcp_metrics_block *tm;
bool ret;
if (!dst)
return false;
rcu_read_lock();
tm = __tcp_get_metrics_req(req, dst);
if (tm && tcp_metric_get(tm, TCP_METRIC_RTT))
ret = true;
else
ret = false;
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)
{
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;
} 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;
static const 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,
TCP_METRICS_ATTR_PAD) < 0)
goto nla_put_failure;
{
int n = 0;
nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
if (!nest)
goto nla_put_failure;
for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) {
u32 val = tm->tcpm_vals[i];
if (!val)
continue;
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,
TCP_METRICS_ATTR_PAD) < 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;
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;
bool match;
spin_lock_bh(&tcp_metrics_lock);
pp = &hb->chain;
for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
match = net ? net_eq(tm_net(tm), net) :
!atomic_read(&tm_net(tm)->count);
if (match) {
*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 struct genl_family tcp_metrics_nl_family __ro_after_init = {
.hdrsize = 0,
.name = TCP_METRICS_GENL_NAME,
.version = TCP_METRICS_GENL_VERSION,
.maxattr = TCP_METRICS_ATTR_MAX,
.netnsok = true,
.module = THIS_MODULE,
.ops = tcp_metrics_nl_ops,
.n_ops = ARRAY_SIZE(tcp_metrics_nl_ops),
};
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 = kvzalloc(size, GFP_KERNEL);
if (!tcp_metrics_hash)
return -ENOMEM;
return 0;
}
static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list)
{
tcp_metrics_flush_all(NULL);
}
static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
.init = tcp_net_metrics_init,
.exit_batch = tcp_net_metrics_exit_batch,
};
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(&tcp_metrics_nl_family);
if (ret < 0)
panic("Could not register tcp_metrics generic netlink\n");
}