tcp: add tcp_ld_RTO_revert() helper (f7456642) · Commits · 戴 / test

net/ipv4/tcp_ipv4.c

+45 −40

Original line number	Diff line number	Diff line
		@@ -403,6 +403,45 @@ void tcp_req_err(struct sock *sk, u32 seq, bool abort)
		}
		EXPORT_SYMBOL(tcp_req_err);

		/* TCP-LD (RFC 6069) logic */
		static void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
		{
		struct inet_connection_sock *icsk = inet_csk(sk);
		struct tcp_sock *tp = tcp_sk(sk);
		struct sk_buff *skb;
		s32 remaining;
		u32 delta_us;

		if (sock_owned_by_user(sk))
		return;

		if (seq != tp->snd_una \|\| !icsk->icsk_retransmits \|\|
		!icsk->icsk_backoff)
		return;

		skb = tcp_rtx_queue_head(sk);
		if (WARN_ON_ONCE(!skb))
		return;

		icsk->icsk_backoff--;
		icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);

		tcp_mstamp_refresh(tp);
		delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
		remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);

		if (remaining > 0) {
		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
		remaining, TCP_RTO_MAX);
		} else {
		/* RTO revert clocked out retransmission.
		* Will retransmit now.
		*/
		tcp_retransmit_timer(sk);
		}
		}

		/*
		* This routine is called by the ICMP module when it gets some
		* sort of error condition. If err < 0 then the socket should
		@@ -423,17 +462,13 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
		{
		const struct iphdr iph = (const struct iphdr )icmp_skb->data;
		struct tcphdr th = (struct tcphdr )(icmp_skb->data + (iph->ihl << 2));
		struct inet_connection_sock *icsk;
		struct tcp_sock *tp;
		struct inet_sock *inet;
		const int type = icmp_hdr(icmp_skb)->type;
		const int code = icmp_hdr(icmp_skb)->code;
		struct sock *sk;
		struct sk_buff *skb;
		struct request_sock *fastopen;
		u32 seq, snd_una;
		s32 remaining;
		u32 delta_us;
		int err;
		struct net *net = dev_net(icmp_skb->dev);

		@@ -476,7 +511,6 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
		goto out;
		}

		icsk = inet_csk(sk);
		tp = tcp_sk(sk);
		/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
		fastopen = rcu_dereference(tp->fastopen_rsk);
		@@ -521,41 +555,12 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
		}

		err = icmp_err_convert[code].errno;
		/* check if icmp_skb allows revert of backoff
		* (see draft-zimmermann-tcp-lcd) */
		if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
		break;
		if (seq != tp->snd_una \|\| !icsk->icsk_retransmits \|\|
		!icsk->icsk_backoff \|\| fastopen)
		break;

		if (sock_owned_by_user(sk))
		break;

		skb = tcp_rtx_queue_head(sk);
		if (WARN_ON_ONCE(!skb))
		break;

		icsk->icsk_backoff--;
		icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
		TCP_TIMEOUT_INIT;
		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);


		tcp_mstamp_refresh(tp);
		delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
		remaining = icsk->icsk_rto -
		usecs_to_jiffies(delta_us);

		if (remaining > 0) {
		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
		remaining, TCP_RTO_MAX);
		} else {
		/* RTO revert clocked out retransmission.
		* Will retransmit now */
		tcp_retransmit_timer(sk);
		}

		/* check if this ICMP message allows revert of backoff.
		* (see RFC 6069)
		*/
		if (!fastopen &&
		(code == ICMP_NET_UNREACH \|\| code == ICMP_HOST_UNREACH))
		tcp_ld_RTO_revert(sk, seq);
		break;
		case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;

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