From: =?ISO-8859-1?q?Ilpo_J=E4rvinen?= <[EMAIL PROTECTED]>
The fack count of any skb in the retransmit queue at any
given point in time is:
(skb->fack_count - head_skb->fack_count)
And we'll use this in the SACK processing loops and possibly
elsewhere too.
Original idea came from David S. Miller, included couple of bug
fixes from Tom Quetchenbach <[EMAIL PROTECTED]>.
Signed-off-by: Ilpo Järvinen <[EMAIL PROTECTED]>
---
include/net/tcp.h | 41 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 5ec1cac..967f256 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -555,6 +555,7 @@ struct tcp_skb_cb {
__u32 seq; /* Starting sequence number */
__u32 end_seq; /* SEQ + FIN + SYN + datalen */
__u32 when; /* used to compute rtt's */
+ unsigned int fack_count; /* speed up SACK processing */
__u8 flags; /* TCP header flags. */
/* NOTE: These must match up to the flags byte in a
@@ -1220,6 +1221,11 @@ static inline struct sk_buff
*tcp_write_queue_next(struct sock *sk, struct sk_bu
return skb->next;
}
+static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct
sk_buff *skb)
+{
+ return skb->prev;
+}
+
#define tcp_for_write_queue(skb, sk) \
for (skb = (sk)->sk_write_queue.next; \
(skb != (struct sk_buff *)&(sk)->sk_write_queue); \
@@ -1241,6 +1247,11 @@ static inline struct sk_buff *tcp_send_head(struct sock
*sk)
static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
{
+ struct sk_buff *prev = tcp_write_queue_prev(sk, skb);
+
+ TCP_SKB_CB(skb)->fack_count = TCP_SKB_CB(prev)->fack_count +
+ tcp_skb_pcount(prev);
+
sk->sk_send_head = skb->next;
if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
sk->sk_send_head = NULL;
@@ -1259,6 +1270,7 @@ static inline void tcp_init_send_head(struct sock *sk)
static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff
*skb)
{
+ TCP_SKB_CB(skb)->fack_count = 0;
__skb_queue_tail(&sk->sk_write_queue, skb);
}
@@ -1275,9 +1287,36 @@ static inline void tcp_add_write_queue_tail(struct sock
*sk, struct sk_buff *skb
}
}
+/* This is only used for tcp_send_synack(), so the write queue should
+ * be empty. If that stops being true, the fack_count assignment
+ * will need to be more elaborate.
+ */
static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff
*skb)
{
+ BUG_ON(!skb_queue_empty(&sk->sk_write_queue));
__skb_queue_head(&sk->sk_write_queue, skb);
+ TCP_SKB_CB(skb)->fack_count = 0;
+}
+
+/* An insert into the middle of the write queue causes the fack
+ * counts in subsequent packets to become invalid, fix them up.
+ */
+static inline void tcp_reset_fack_counts(struct sock *sk, struct sk_buff *skb)
+{
+ struct sk_buff *prev = skb->prev;
+ unsigned int fc = 0;
+
+ if (prev != (struct sk_buff *) &sk->sk_write_queue)
+ fc = TCP_SKB_CB(prev)->fack_count + tcp_skb_pcount(prev);
+
+ tcp_for_write_queue_from(skb, sk) {
+ if (!before(TCP_SKB_CB(skb)->seq, tcp_sk(sk)->snd_nxt) ||
+ TCP_SKB_CB(skb)->fack_count == fc)
+ break;
+
+ TCP_SKB_CB(skb)->fack_count = fc;
+ fc += tcp_skb_pcount(skb);
+ }
}
/* Insert buff after skb on the write queue of sk. */
@@ -1286,6 +1325,7 @@ static inline void tcp_insert_write_queue_after(struct
sk_buff *skb,
struct sock *sk)
{
__skb_append(skb, buff, &sk->sk_write_queue);
+ tcp_reset_fack_counts(sk, buff);
}
/* Insert skb between prev and next on the write queue of sk. */
@@ -1294,6 +1334,7 @@ static inline void tcp_insert_write_queue_before(struct
sk_buff *new,
struct sock *sk)
{
__skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
+ tcp_reset_fack_counts(sk, new);
if (sk->sk_send_head == skb)
sk->sk_send_head = new;
--
1.5.0.6
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