Ack vectors grow proportional to the window size. If an ack vector does not fit
into a single option, it must be spread across multiple options. This patch
will allow for windows to grow larger.
Committer note: Simplified the patch a bit, original algorithm kept.
Signed-off-by: Andrea Bittau <a.bittau@xxxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxx>
---
net/dccp/ackvec.c | 46 ++++++++++++++++++++++++++++++++--------------
1 files changed, 32 insertions(+), 14 deletions(-)
diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
index 41d34d1..bdf1bb7 100644
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -68,10 +68,15 @@ int dccp_insert_option_ackvec(struct soc
{
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
- int len = av->dccpav_vec_len + 2;
+ /* Figure out how many options do we need to represent the ackvec */
+ const u16 nr_opts = (av->dccpav_vec_len +
+ DCCP_MAX_ACKVEC_OPT_LEN - 1) /
+ DCCP_MAX_ACKVEC_OPT_LEN;
+ u16 len = av->dccpav_vec_len + 2 * nr_opts, i;
struct timeval now;
u32 elapsed_time;
- unsigned char *to, *from;
+ const unsigned char *tail, *from;
+ unsigned char *to;
struct dccp_ackvec_record *avr;
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
@@ -90,24 +95,37 @@ int dccp_insert_option_ackvec(struct soc
DCCP_SKB_CB(skb)->dccpd_opt_len += len;
- to = skb_push(skb, len);
- *to++ = DCCPO_ACK_VECTOR_0;
- *to++ = len;
-
+ to = skb_push(skb, len);
len = av->dccpav_vec_len;
from = av->dccpav_buf + av->dccpav_buf_head;
+ tail = av->dccpav_buf + DCCP_MAX_ACKVEC_LEN;
+
+ for (i = 0; i < nr_opts; ++i) {
+ int copylen = len;
+
+ if (len > DCCP_MAX_ACKVEC_OPT_LEN)
+ copylen = DCCP_MAX_ACKVEC_OPT_LEN;
- /* Check if buf_head wraps */
- if ((int)av->dccpav_buf_head + len > DCCP_MAX_ACKVEC_LEN) {
- const u32 tailsize = DCCP_MAX_ACKVEC_LEN - av->dccpav_buf_head;
+ *to++ = DCCPO_ACK_VECTOR_0;
+ *to++ = copylen + 2;
+
+ /* Check if buf_head wraps */
+ if (from + copylen > tail) {
+ const u16 tailsize = tail - from;
+
+ memcpy(to, from, tailsize);
+ to += tailsize;
+ len -= tailsize;
+ copylen -= tailsize;
+ from = av->dccpav_buf;
+ }
- memcpy(to, from, tailsize);
- to += tailsize;
- len -= tailsize;
- from = av->dccpav_buf;
+ memcpy(to, from, copylen);
+ from += copylen;
+ to += copylen;
+ len -= copylen;
}
- memcpy(to, from, len);
/*
* From RFC 4340, A.2:
*
--
1.4.2.1.g3d5c
-
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