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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c52
1 files changed, 36 insertions, 16 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 976034f82320..b5e315f13641 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1307,25 +1307,26 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
return in_sack;
}
-static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
- struct tcp_sacktag_state *state,
+/* Mark the given newly-SACKed range as such, adjusting counters and hints. */
+static u8 tcp_sacktag_one(struct sock *sk,
+ struct tcp_sacktag_state *state, u8 sacked,
+ u32 start_seq, u32 end_seq,
int dup_sack, int pcount)
{
struct tcp_sock *tp = tcp_sk(sk);
- u8 sacked = TCP_SKB_CB(skb)->sacked;
int fack_count = state->fack_count;
/* Account D-SACK for retransmitted packet. */
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans &&
- after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
+ after(end_seq, tp->undo_marker))
tp->undo_retrans--;
if (sacked & TCPCB_SACKED_ACKED)
state->reord = min(fack_count, state->reord);
}
/* Nothing to do; acked frame is about to be dropped (was ACKed). */
- if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
+ if (!after(end_seq, tp->snd_una))
return sacked;
if (!(sacked & TCPCB_SACKED_ACKED)) {
@@ -1344,13 +1345,13 @@ static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
/* New sack for not retransmitted frame,
* which was in hole. It is reordering.
*/
- if (before(TCP_SKB_CB(skb)->seq,
+ if (before(start_seq,
tcp_highest_sack_seq(tp)))
state->reord = min(fack_count,
state->reord);
/* SACK enhanced F-RTO (RFC4138; Appendix B) */
- if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
+ if (!after(end_seq, tp->frto_highmark))
state->flag |= FLAG_ONLY_ORIG_SACKED;
}
@@ -1368,8 +1369,7 @@ static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
- before(TCP_SKB_CB(skb)->seq,
- TCP_SKB_CB(tp->lost_skb_hint)->seq))
+ before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq))
tp->lost_cnt_hint += pcount;
if (fack_count > tp->fackets_out)
@@ -1388,6 +1388,9 @@ static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
return sacked;
}
+/* Shift newly-SACKed bytes from this skb to the immediately previous
+ * already-SACKed sk_buff. Mark the newly-SACKed bytes as such.
+ */
static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
struct tcp_sacktag_state *state,
unsigned int pcount, int shifted, int mss,
@@ -1395,9 +1398,20 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *prev = tcp_write_queue_prev(sk, skb);
+ u32 start_seq = TCP_SKB_CB(skb)->seq; /* start of newly-SACKed */
+ u32 end_seq = start_seq + shifted; /* end of newly-SACKed */
BUG_ON(!pcount);
+ /* Adjust counters and hints for the newly sacked sequence
+ * range but discard the return value since prev is already
+ * marked. We must tag the range first because the seq
+ * advancement below implicitly advances
+ * tcp_highest_sack_seq() when skb is highest_sack.
+ */
+ tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
+ start_seq, end_seq, dup_sack, pcount);
+
if (skb == tp->lost_skb_hint)
tp->lost_cnt_hint += pcount;
@@ -1424,9 +1438,6 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
skb_shinfo(skb)->gso_type = 0;
}
- /* We discard results */
- tcp_sacktag_one(skb, sk, state, dup_sack, pcount);
-
/* Difference in this won't matter, both ACKed by the same cumul. ACK */
TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
@@ -1574,6 +1585,10 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
}
}
+ /* tcp_sacktag_one() won't SACK-tag ranges below snd_una */
+ if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
+ goto fallback;
+
if (!skb_shift(prev, skb, len))
goto fallback;
if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
@@ -1664,10 +1679,14 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
break;
if (in_sack) {
- TCP_SKB_CB(skb)->sacked = tcp_sacktag_one(skb, sk,
- state,
- dup_sack,
- tcp_skb_pcount(skb));
+ TCP_SKB_CB(skb)->sacked =
+ tcp_sacktag_one(sk,
+ state,
+ TCP_SKB_CB(skb)->sacked,
+ TCP_SKB_CB(skb)->seq,
+ TCP_SKB_CB(skb)->end_seq,
+ dup_sack,
+ tcp_skb_pcount(skb));
if (!before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(tp)))
@@ -2554,6 +2573,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
if (cnt > packets) {
if ((tcp_is_sack(tp) && !tcp_is_fack(tp)) ||
+ (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
(oldcnt >= packets))
break;