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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c88
1 files changed, 51 insertions, 37 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 075ab4d5af5e..8fdd27b17306 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -100,6 +100,7 @@ int sysctl_tcp_thin_dupack __read_mostly;
int sysctl_tcp_moderate_rcvbuf __read_mostly = 1;
int sysctl_tcp_early_retrans __read_mostly = 3;
+int sysctl_tcp_invalid_ratelimit __read_mostly = HZ/2;
#define FLAG_DATA 0x01 /* Incoming frame contained data. */
#define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */
@@ -3183,8 +3184,10 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
tp->fackets_out -= min(pkts_acked, tp->fackets_out);
- if (ca_ops->pkts_acked)
- ca_ops->pkts_acked(sk, pkts_acked, ca_seq_rtt_us);
+ if (ca_ops->pkts_acked) {
+ long rtt_us = min_t(ulong, ca_seq_rtt_us, sack_rtt_us);
+ ca_ops->pkts_acked(sk, pkts_acked, rtt_us);
+ }
} else if (skb && rtt_update && sack_rtt_us >= 0 &&
sack_rtt_us > skb_mstamp_us_delta(&now, &skb->skb_mstamp)) {
@@ -3319,13 +3322,22 @@ static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32
}
/* RFC 5961 7 [ACK Throttling] */
-static void tcp_send_challenge_ack(struct sock *sk)
+static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb)
{
/* unprotected vars, we dont care of overwrites */
static u32 challenge_timestamp;
static unsigned int challenge_count;
- u32 now = jiffies / HZ;
+ struct tcp_sock *tp = tcp_sk(sk);
+ u32 now;
+
+ /* First check our per-socket dupack rate limit. */
+ if (tcp_oow_rate_limited(sock_net(sk), skb,
+ LINUX_MIB_TCPACKSKIPPEDCHALLENGE,
+ &tp->last_oow_ack_time))
+ return;
+ /* Then check the check host-wide RFC 5961 rate limit. */
+ now = jiffies / HZ;
if (now != challenge_timestamp) {
challenge_timestamp = now;
challenge_count = 0;
@@ -3358,34 +3370,34 @@ static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
}
/* This routine deals with acks during a TLP episode.
+ * We mark the end of a TLP episode on receiving TLP dupack or when
+ * ack is after tlp_high_seq.
* Ref: loss detection algorithm in draft-dukkipati-tcpm-tcp-loss-probe.
*/
static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
- bool is_tlp_dupack = (ack == tp->tlp_high_seq) &&
- !(flag & (FLAG_SND_UNA_ADVANCED |
- FLAG_NOT_DUP | FLAG_DATA_SACKED));
- /* Mark the end of TLP episode on receiving TLP dupack or when
- * ack is after tlp_high_seq.
- */
- if (is_tlp_dupack) {
- tp->tlp_high_seq = 0;
+ if (before(ack, tp->tlp_high_seq))
return;
- }
- if (after(ack, tp->tlp_high_seq)) {
+ if (flag & FLAG_DSACKING_ACK) {
+ /* This DSACK means original and TLP probe arrived; no loss */
+ tp->tlp_high_seq = 0;
+ } else if (after(ack, tp->tlp_high_seq)) {
+ /* ACK advances: there was a loss, so reduce cwnd. Reset
+ * tlp_high_seq in tcp_init_cwnd_reduction()
+ */
+ tcp_init_cwnd_reduction(sk);
+ tcp_set_ca_state(sk, TCP_CA_CWR);
+ tcp_end_cwnd_reduction(sk);
+ tcp_try_keep_open(sk);
+ NET_INC_STATS_BH(sock_net(sk),
+ LINUX_MIB_TCPLOSSPROBERECOVERY);
+ } else if (!(flag & (FLAG_SND_UNA_ADVANCED |
+ FLAG_NOT_DUP | FLAG_DATA_SACKED))) {
+ /* Pure dupack: original and TLP probe arrived; no loss */
tp->tlp_high_seq = 0;
- /* Don't reduce cwnd if DSACK arrives for TLP retrans. */
- if (!(flag & FLAG_DSACKING_ACK)) {
- tcp_init_cwnd_reduction(sk);
- tcp_set_ca_state(sk, TCP_CA_CWR);
- tcp_end_cwnd_reduction(sk);
- tcp_try_keep_open(sk);
- NET_INC_STATS_BH(sock_net(sk),
- LINUX_MIB_TCPLOSSPROBERECOVERY);
- }
}
}
@@ -3421,7 +3433,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
if (before(ack, prior_snd_una)) {
/* RFC 5961 5.2 [Blind Data Injection Attack].[Mitigation] */
if (before(ack, prior_snd_una - tp->max_window)) {
- tcp_send_challenge_ack(sk);
+ tcp_send_challenge_ack(sk, skb);
return -1;
}
goto old_ack;
@@ -4990,7 +5002,10 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
tcp_paws_discard(sk, skb)) {
if (!th->rst) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED);
- tcp_send_dupack(sk, skb);
+ if (!tcp_oow_rate_limited(sock_net(sk), skb,
+ LINUX_MIB_TCPACKSKIPPEDPAWS,
+ &tp->last_oow_ack_time))
+ tcp_send_dupack(sk, skb);
goto discard;
}
/* Reset is accepted even if it did not pass PAWS. */
@@ -5007,7 +5022,10 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
if (!th->rst) {
if (th->syn)
goto syn_challenge;
- tcp_send_dupack(sk, skb);
+ if (!tcp_oow_rate_limited(sock_net(sk), skb,
+ LINUX_MIB_TCPACKSKIPPEDSEQ,
+ &tp->last_oow_ack_time))
+ tcp_send_dupack(sk, skb);
}
goto discard;
}
@@ -5023,7 +5041,7 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt)
tcp_reset(sk);
else
- tcp_send_challenge_ack(sk);
+ tcp_send_challenge_ack(sk, skb);
goto discard;
}
@@ -5037,7 +5055,7 @@ syn_challenge:
if (syn_inerr)
TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE);
- tcp_send_challenge_ack(sk);
+ tcp_send_challenge_ack(sk, skb);
goto discard;
}
@@ -5870,10 +5888,9 @@ static inline void pr_drop_req(struct request_sock *req, __u16 port, int family)
* TCP ECN negotiation.
*
* Exception: tcp_ca wants ECN. This is required for DCTCP
- * congestion control; it requires setting ECT on all packets,
- * including SYN. We inverse the test in this case: If our
- * local socket wants ECN, but peer only set ece/cwr (but not
- * ECT in IP header) its probably a non-DCTCP aware sender.
+ * congestion control: Linux DCTCP asserts ECT on all packets,
+ * including SYN, which is most optimal solution; however,
+ * others, such as FreeBSD do not.
*/
static void tcp_ecn_create_request(struct request_sock *req,
const struct sk_buff *skb,
@@ -5883,18 +5900,15 @@ static void tcp_ecn_create_request(struct request_sock *req,
const struct tcphdr *th = tcp_hdr(skb);
const struct net *net = sock_net(listen_sk);
bool th_ecn = th->ece && th->cwr;
- bool ect, need_ecn, ecn_ok;
+ bool ect, ecn_ok;
if (!th_ecn)
return;
ect = !INET_ECN_is_not_ect(TCP_SKB_CB(skb)->ip_dsfield);
- need_ecn = tcp_ca_needs_ecn(listen_sk);
ecn_ok = net->ipv4.sysctl_tcp_ecn || dst_feature(dst, RTAX_FEATURE_ECN);
- if (!ect && !need_ecn && ecn_ok)
- inet_rsk(req)->ecn_ok = 1;
- else if (ect && need_ecn)
+ if ((!ect && ecn_ok) || tcp_ca_needs_ecn(listen_sk))
inet_rsk(req)->ecn_ok = 1;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-24 05:08:49 +0100