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tcp: Use BPF timeout setting for SYN ACK RTO

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When setting RTO through BPF program, some SYN ACK packets were unaffected
and continued to use TCP_TIMEOUT_INIT constant. This patch adds timeout
option to struct request_sock. Option is initialized with TCP_TIMEOUT_INIT
and is reassigned through BPF using tcp_timeout_init call. SYN ACK
retransmits now use newly added timeout option.

Signed-off-by: Akhmat Karakotov <hmukos@yandex-team.ru>
Acked-by: Martin KaFai Lau <kafai@fb.com>

v2:
	- Add timeout option to struct request_sock. Do not call
	  tcp_timeout_init on every syn ack retransmit.

v3:
	- Use unsigned long for min. Bound tcp_timeout_init to TCP_RTO_MAX.

v4:
	- Refactor duplicate code by adding reqsk_timeout function.
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Akhmat Karakotov 2022-01-28 22:26:21 +03:00 committed by David S. Miller
parent 0b6b0d3113
commit 5903123f66
6 changed files with 19 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/net/inet_connection_sock.h
View File

@ -285,6 +285,14 @@ static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
static inline unsigned long
reqsk_timeout(struct request_sock *req, unsigned long max_timeout)
{
u64 timeout = (u64)req->timeout << req->num_timeout;
return (unsigned long)min_t(u64, timeout, max_timeout);
}
static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
{
/* The below has to be done to allow calling inet_csk_destroy_sock */

2
include/net/request_sock.h
View File

@ -70,6 +70,7 @@ struct request_sock {
struct saved_syn *saved_syn;
u32 secid;
u32 peer_secid;
u32 timeout;
};
static inline struct request_sock *inet_reqsk(const struct sock *sk)
@ -104,6 +105,7 @@ reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
sk_node_init(&req_to_sk(req)->sk_node);
sk_tx_queue_clear(req_to_sk(req));
req->saved_syn = NULL;
req->timeout = 0;
req->num_timeout = 0;
req->num_retrans = 0;
req->sk = NULL;

2
include/net/tcp.h
View File

@ -2358,7 +2358,7 @@ static inline u32 tcp_timeout_init(struct sock *sk)
if (timeout <= 0)
timeout = TCP_TIMEOUT_INIT;
return timeout;
return min_t(int, timeout, TCP_RTO_MAX);
}
static inline u32 tcp_rwnd_init_bpf(struct sock *sk)

5
net/ipv4/inet_connection_sock.c
View File

@ -866,12 +866,9 @@ static void reqsk_timer_handler(struct timer_list *t)
(!resend ||
!inet_rtx_syn_ack(sk_listener, req) ||
inet_rsk(req)->acked)) {
unsigned long timeo;
if (req->num_timeout++ == 0)
atomic_dec(&queue->young);
timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
mod_timer(&req->rsk_timer, jiffies + timeo);
mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX));
if (!nreq)
return;

8
net/ipv4/tcp_input.c
View File

@ -6723,6 +6723,7 @@ struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
ireq->ireq_state = TCP_NEW_SYN_RECV;
write_pnet(&ireq->ireq_net, sock_net(sk_listener));
ireq->ireq_family = sk_listener->sk_family;
req->timeout = TCP_TIMEOUT_INIT;
}
return req;
@ -6939,9 +6940,10 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
sock_put(fastopen_sk);
} else {
tcp_rsk(req)->tfo_listener = false;
if (!want_cookie)
inet_csk_reqsk_queue_hash_add(sk, req,
tcp_timeout_init((struct sock *)req));
if (!want_cookie) {
req->timeout = tcp_timeout_init((struct sock *)req);
inet_csk_reqsk_queue_hash_add(sk, req, req->timeout);
}
af_ops->send_synack(sk, dst, &fl, req, &foc,
!want_cookie ? TCP_SYNACK_NORMAL :
TCP_SYNACK_COOKIE,

5
net/ipv4/tcp_minisocks.c
View File

@ -583,7 +583,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
* it can be estimated (approximately)
* from another data.
*/
tmp_opt.ts_recent_stamp = ktime_get_seconds() - ((TCP_TIMEOUT_INIT/HZ)<<req->num_timeout);
tmp_opt.ts_recent_stamp = ktime_get_seconds() - reqsk_timeout(req, TCP_RTO_MAX) / HZ;
paws_reject = tcp_paws_reject(&tmp_opt, th->rst);
}
}
@ -622,8 +622,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
!inet_rtx_syn_ack(sk, req)) {
unsigned long expires = jiffies;
expires += min(TCP_TIMEOUT_INIT << req->num_timeout,
TCP_RTO_MAX);
expires += reqsk_timeout(req, TCP_RTO_MAX);
if (!fastopen)
mod_timer_pending(&req->rsk_timer, expires);
else