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[DCCP] ackvec: Split long ack vectors across multiple options 

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@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This commit is contained in:
Andrea Bittau 2006-11-26 01:04:40 -02:00 committed by David S. Miller
parent bdf13d208d
commit 522f1d095b
1 changed files with 32 additions and 14 deletions
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46
net/dccp/ackvec.c
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@ -68,10 +68,15 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
{
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 sock *sk, struct sk_buff *skb)
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;
/* 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;
for (i = 0; i < nr_opts; ++i) {
int copylen = len;
memcpy(to, from, tailsize);
to += tailsize;
len -= tailsize;
from = av->dccpav_buf;
if (len > DCCP_MAX_ACKVEC_OPT_LEN)
copylen = DCCP_MAX_ACKVEC_OPT_LEN;
*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, copylen);
from += copylen;
to += copylen;
len -= copylen;
}
memcpy(to, from, len);
/*
* From RFC 4340, A.2:
*