The length of the circular Ack Vector buffer is now determined dynamically,
as the span between head to tail.
Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]>
---
net/dccp/ackvec.c | 21 +++++++++++++++++++++
net/dccp/ackvec.h | 7 +++++++
net/dccp/options.c | 7 ++++---
3 files changed, 32 insertions(+), 3 deletions(-)
--- a/net/dccp/ackvec.h
+++ b/net/dccp/ackvec.h
@@ -22,6 +22,7 @@
* the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1
* will be sufficient for most cases of low Ack Ratios, using a value of 2
gives
* more headroom if Ack Ratio is higher or when the sender acknowledges slowly.
+ * The maximum value is bounded by the u16 types for indices and functions.
*/
#define DCCPAV_NUM_ACKVECS 2
#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
@@ -110,6 +111,7 @@ extern int dccp_ackvec_add(struct dccp_ackvec *av, const
struct sock *sk,
extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8
sum);
extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
+extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av);
static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
{
@@ -149,6 +151,11 @@ static inline int dccp_ackvec_update_records(struct
dccp_ackvec *av, u64 seq, u8
return -1;
}
+static inline u16 dccp_ackvec_buflen(const struct dccp_ackvec *av)
+{
+ return 0;
+}
+
static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
{
return true;
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -114,6 +114,27 @@ static struct dccp_ackvec_record
*dccp_ackvec_lookup(struct list_head *av_list,
}
/*
+ * Buffer index and length computation using modulo-buffersize arithmetic.
+ * Note that, as pointers move from right to left, head is `before' tail.
+ */
+static inline u16 dccp_ackvec_idx_add(const u16 a, const u16 b)
+{
+ return (a + b) % DCCPAV_MAX_ACKVEC_LEN;
+}
+
+static inline u16 dccp_ackvec_idx_sub(const u16 a, const u16 b)
+{
+ return dccp_ackvec_idx_add(a, DCCPAV_MAX_ACKVEC_LEN - b);
+}
+
+u16 dccp_ackvec_buflen(const struct dccp_ackvec *av)
+{
+ if (unlikely(av->av_overflow))
+ return DCCPAV_MAX_ACKVEC_LEN;
+ return dccp_ackvec_idx_sub(av->av_buf_tail, av->av_buf_head);
+}
+
+/*
* If several packets are missing, the HC-Receiver may prefer to enter multiple
* bytes with run length 0, rather than a single byte with a larger run length;
* this simplifies table updates if one of the missing packets arrives.
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -432,9 +432,10 @@ static int dccp_insert_option_timestamp_echo(struct
dccp_sock *dp,
int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
{
struct dccp_ackvec *av = dccp_sk(sk)->dccps_hc_rx_ackvec;
+ const u16 buflen = dccp_ackvec_buflen(av);
/* Figure out how many options do we need to represent the ackvec */
- const u16 nr_opts = DIV_ROUND_UP(av->av_vec_len,
DCCP_SINGLE_OPT_MAXLEN);
- u16 len = av->av_vec_len + 2 * nr_opts;
+ const u16 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN);
+ u16 len = buflen + 2 * nr_opts;
u8 i, nonce = 0;
const unsigned char *tail, *from;
unsigned char *to;
@@ -451,7 +452,7 @@ int dccp_insert_option_ackvec(struct sock *sk, struct
sk_buff *skb)
DCCP_SKB_CB(skb)->dccpd_opt_len += len;
to = skb_push(skb, len);
- len = av->av_vec_len;
+ len = buflen;
from = av->av_buf + av->av_buf_head;
tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
--
1.5.3.GIT
-
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