: New RX history implementation

index 5a61b1b..5650f06 100644
@@ -34,7 +34,6 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
-
 #include <linux/string.h>
 #include "packet_history.h"
 

@@ -289,6 +288,33 @@ void dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
 
 EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
 
+static struct kmem_cache *tfrcxh;
+
+int tfrc_rx_hist_init(struct tfrc_rx_hist *h)
+{
+	int i;
+
+	for (i = 0; i <= NDUPACK; i++) {
+		h->ring[i] = kmem_cache_alloc(tfrcxh, GFP_ATOMIC);
+		if (h->ring[i] = NULL)
+			return 1;
+	}
+	h->loss_count = 0;
+	h->loss_start = 0;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_init);
+
+void tfrc_rx_hist_cleanup(struct tfrc_rx_hist *h)
+{
+	int i;
+
+	for (i=0; i <= NDUPACK; i++)
+		if (h->ring[i] != NULL)
+			kmem_cache_free(tfrcxh, h->ring[i]);
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_cleanup);
+
 void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
 {
 	struct dccp_rx_hist_entry *entry, *next;

@@ -300,3 +326,73 @@ void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
 }
 
 EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
+
+/**
+ * tfrc_rx_sample_rtt  -  Sample RTT from timestamp / CCVal
+ * Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able
+ * to compute a sample with given data - calling function should check this.
+ */
+u32 tfrc_rx_sample_rtt(struct tfrc_rx_hist *h, struct sk_buff *skb)
+{
+	u32 sample = 0,
+	    delta_v = SUB16(dccp_hdr(skb)->dccph_ccval, rtt_last_s(h)->ccval);
+
+	if (delta_v < 1 || delta_v > 4) {	/* unsuitable CCVal delta */
+
+		if (h->rtt_sample_prev = 2) {	/* previous candidate stored */
+			sample = SUB16(rtt_prev_s(h)->ccval,
+				       rtt_last_s(h)->ccval);
+			if (sample)
+				sample = 4 / sample
+				       * ktime_us_delta(rtt_prev_s(h)->stamp,
+							rtt_last_s(h)->stamp);
+			else    /*
+				 * FIXME: This condition is in principle not
+				 * possible but occurs when CCID is used for
+				 * two-way data traffic. I have tried to trace
+				 * it, but the cause does not seem to be here.
+				 */
+				DCCP_BUG("please report to [email protected]"
+					 " => prev = %u, last = %u",
+					 rtt_prev_s(h)->ccval,
+					 rtt_last_s(h)->ccval);
+		} else if (delta_v < 1) {
+			h->rtt_sample_prev = 1;
+			goto keep_ref_for_next_time;
+		}
+
+	} else if (delta_v = 4) {     /* optimal match */
+		sample = ktime_to_us(net_timedelta(rtt_last_s(h)->stamp));
+
+	} else	{		       /* suboptimal match */
+		h->rtt_sample_prev = 2;
+		goto keep_ref_for_next_time;
+	}
+
+	if (unlikely(sample > DCCP_SANE_RTT_MAX)) {
+		DCCP_WARN("RTT sample %u too large, using max\n", sample);
+		sample = DCCP_SANE_RTT_MAX;
+	}
+
+	h->rtt_sample_prev = 0;	       /* use current entry as next reference */
+keep_ref_for_next_time:
+
+	return sample;
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_sample_rtt);
+
+/* Module initialisation and cleanup routines */
+int __init packet_history_init(void)
+{
+	tfrcxh = kmem_cache_create("tfrc_rx_hist",
+				   sizeof(struct tfrc_rx_hist_entry),
+				   0, SLAB_HWCACHE_ALIGN, NULL);
+
+	return tfrcxh = NULL ? -ENOBUFS : 0;
+}
+
+void __exit packet_history_cleanup(void)
+{
+	if (tfrcxh != NULL)
+		kmem_cache_destroy(tfrcxh);
+}

173 lines not on this page · raw message

index 5a4b055..d432665 100644
@@ -7,18 +7,25 @@
 #include <linux/moduleparam.h>
 #include "tfrc.h"
 
+/* Initialisation / Clean-up routines */
 extern int  dccp_li_init(void);
 extern void dccp_li_exit(void);
+extern int  packet_history_init(void);
+extern void packet_history_cleanup(void);
 
 static int __init tfrc_module_init(void)
 {
 	int rc = dccp_li_init();
 
+	if (rc = 0)
+		rc = packet_history_init();
+
 	return rc;
 }
 
 static void __exit tfrc_module_exit(void)
 {
+	packet_history_cleanup();
 	dccp_li_exit();
 }
 

index ee97950..f4a5ea1 100644
@@ -334,6 +334,7 @@ struct dccp_skb_cb {
 
 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
 
+/* RFC 4340, sec. 7.7 */
 static inline int dccp_non_data_packet(const struct sk_buff *skb)
 {
 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

@@ -346,6 +347,17 @@ static inline int dccp_non_data_packet(const struct sk_buff *skb)
 	       type = DCCP_PKT_SYNCACK;
 }
 
+/* RFC 4340, sec. 7.7 */
+static inline int dccp_data_packet(const struct sk_buff *skb)
+{
+	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
+
+	return type = DCCP_PKT_DATA	 ||
+	       type = DCCP_PKT_DATAACK  ||
+	       type = DCCP_PKT_REQUEST  ||
+	       type = DCCP_PKT_RESPONSE;
+}
+
 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
 {
 	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;