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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2008-09-04 07:30:19 +0200
committerGerrit Renker <gerrit@erg.abdn.ac.uk>2008-09-04 07:45:34 +0200
commitce177ae2e6b196659e93a9408cc1f5f13f206d13 (patch)
tree4ecd5266014cb5214c9e4955e753331f9fb23645 /net/dccp
parentdccp tfrc/ccid-3: Computing Loss Rate from Loss Event Rate (diff)
downloadlinux-ce177ae2e6b196659e93a9408cc1f5f13f206d13.tar.xz
linux-ce177ae2e6b196659e93a9408cc1f5f13f206d13.zip
dccp ccid-3: Remove redundant 'options_received' struct
The `options_received' struct is redundant, since it re-duplicates the existing `p' and `x_recv' fields. This patch removes the sub-struct and migrates the format conversion operations (cf. below) to ccid3_hc_tx_parse_options(). Why the fields are redundant ---------------------------- The Loss Event Rate p and the Receive Rate x_recv are initially 0 when first loading CCID-3, as ccid_new() zeroes out the entire ccid3_hc_tx_sock. When Loss Event Rate or Receive Rate options are received, they are stored by ccid3_hc_tx_parse_options() into the fields `ccid3or_loss_event_rate' and `ccid3or_receive_rate' of the sub-struct `options_received' in ccid3_hc_tx_sock. After parsing (considering only the established state - dccp_rcv_established()), the packet is passed on to ccid_hc_tx_packet_recv(). This calls the CCID-3 specific routine ccid3_hc_tx_packet_recv(), which performs the following copy operations between fields of ccid3_hc_tx_sock: * hctx->options_received.ccid3or_receive_rate is copied into hctx->x_recv, after scaling it for fixpoint arithmetic, by 2^64; * hctx->options_received.ccid3or_loss_event_rate is copied into hctx->p, considering the above special cases; in addition, a value of 0 here needs to be mapped into p=0 (when no Loss Event Rate option has been received yet). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp')
-rw-r--r--net/dccp/ccids/ccid3.c24
-rw-r--r--net/dccp/ccids/ccid3.h7
2 files changed, 8 insertions, 23 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 206204551f4d..e7db8a4ee642 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -370,11 +370,10 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- struct ccid3_options_received *opt_recv = &hctx->options_received;
struct tfrc_tx_hist_entry *acked;
ktime_t now;
unsigned long t_nfb;
- u32 pinv, r_sample;
+ u32 r_sample;
/* we are only interested in ACKs */
if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
@@ -404,17 +403,6 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9);
- /* Update receive rate in units of 64 * bytes/second */
- hctx->x_recv = opt_recv->ccid3or_receive_rate;
- hctx->x_recv <<= 6;
-
- /* Update loss event rate (which is scaled by 1e6) */
- pinv = opt_recv->ccid3or_loss_event_rate;
- if (pinv == 0)
- hctx->p = 0;
- else
- hctx->p = tfrc_invert_loss_event_rate(pinv);
-
/*
* Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
*/
@@ -487,7 +475,6 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
u8 option, u8 *optval, u8 optlen)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- struct ccid3_options_received *opt_recv = &hctx->options_received;
__be32 opt_val;
switch (option) {
@@ -504,11 +491,16 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
opt_val = ntohl(get_unaligned((__be32 *)optval));
if (option == TFRC_OPT_RECEIVE_RATE) {
- opt_recv->ccid3or_receive_rate = opt_val;
+ /* Receive Rate is kept in units of 64 bytes/second */
+ hctx->x_recv = opt_val;
+ hctx->x_recv <<= 6;
+
ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
dccp_role(sk), sk, opt_val);
} else {
- opt_recv->ccid3or_loss_event_rate = opt_val;
+ /* Update the fixpoint Loss Event Rate fraction */
+ hctx->p = tfrc_invert_loss_event_rate(opt_val);
+
ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
dccp_role(sk), sk, opt_val);
}
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 2268785ae8ee..ae210786c895 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -70,11 +70,6 @@ enum ccid3_options {
TFRC_OPT_RECEIVE_RATE = 194,
};
-struct ccid3_options_received {
- u32 ccid3or_loss_event_rate;
- u32 ccid3or_receive_rate;
-};
-
/* TFRC sender states */
enum ccid3_hc_tx_states {
TFRC_SSTATE_NO_SENT = 1,
@@ -101,7 +96,6 @@ enum ccid3_hc_tx_states {
* @t_ld - Time last doubled during slow start
* @t_nom - Nominal send time of next packet
* @hist - Packet history
- * @options_received - Parsed set of retrieved options
*/
struct ccid3_hc_tx_sock {
u64 x;
@@ -119,7 +113,6 @@ struct ccid3_hc_tx_sock {
ktime_t t_ld;
ktime_t t_nom;
struct tfrc_tx_hist_entry *hist;
- struct ccid3_options_received options_received;
};
static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)