Add emulation of delay profiles, which lets you model various

types of MAC overheads such as preambles, link level retransmissions
and more.

Note- this commit changes the userland/kernel ABI for pipes
(but not for ordinary firewall rules) so you need to rebuild
kernel and /sbin/ipfw to use dummynet features.

Please check the manpage for details on the new feature.

The MFC would be trivial but it breaks the ABI, so it will
be postponed until after 7.2 is released.

Interested users are welcome to apply the patch manually
to their RELENG_7 tree.

Work supported by the European Commission, Projects Onelab and
Onelab2 (contract 224263).

1 files changed, 34 insertions, 2 deletions

diff --git a/sys/netinet/ip_dummynet.h b/sys/netinet/ip_dummynet.h
index 0a37e6c..6e102f4 100644
--- a/sys/netinet/ip_dummynet.h
+++ b/sys/netinet/ip_dummynet.h
@@ -204,7 +204,18 @@ struct dn_flow_queue {
     struct mbuf *head, *tail ;	/* queue of packets */
     u_int len ;
     u_int len_bytes ;
-    u_long numbytes ;		/* credit for transmission (dynamic queues) */
+
+    /*
+     * When we emulate MAC overheads, or channel unavailability due
+     * to other traffic on a shared medium, we augment the packet at
+     * the head of the queue with an 'extra_bits' field representsing
+     * the additional delay the packet will be subject to:
+     *		extra_bits = bw*unavailable_time.
+     * With large bandwidth and large delays, extra_bits (and also numbytes)
+     * can become very large, so better play safe and use 64 bit
+     */
+    dn_key numbytes ;		/* credit for transmission (dynamic queues) */
+    dn_key extra_bits;		/* extra bits simulating unavailable channel */
 
     u_int64_t tot_pkts ;	/* statistics counters	*/
     u_int64_t tot_bytes ;
@@ -252,6 +263,7 @@ struct dn_flow_set {
 #define DN_IS_GENTLE_RED	0x0004
 #define DN_QSIZE_IS_BYTES	0x0008	/* queue size is measured in bytes */
 #define DN_NOERROR		0x0010	/* do not report ENOBUFS on drops  */
+#define	DN_HAS_PROFILE		0x0020	/* the pipe has a delay profile. */
 #define DN_IS_PIPE		0x4000
 #define DN_IS_QUEUE		0x8000
 
@@ -324,7 +336,9 @@ struct dn_pipe {		/* a pipe */
 
     dn_key V ;			/* virtual time */
     int sum;			/* sum of weights of all active sessions */
-    int numbytes;		/* bits I can transmit (more or less). */
+
+    /* Same as in dn_flow_queue, numbytes can become large */
+    dn_key numbytes;		/* bits I can transmit (more or less). */
 
     dn_key sched_time ;		/* time pipe was scheduled in ready_heap */
 
@@ -337,7 +351,25 @@ struct dn_pipe {		/* a pipe */
     int ready ; /* set if ifp != NULL and we got a signal from it */
 
     struct dn_flow_set fs ; /* used with fixed-rate flows */
+
+    /* fields to simulate a delay profile */
+
+#define ED_MAX_NAME_LEN		32
+    char name[ED_MAX_NAME_LEN];
+    int loss_level;
+    int samples_no;
+    int *samples;
 };
+
+/* dn_pipe_max is used to pass pipe configuration from userland onto
+ * kernel space and back
+ */
+#define ED_MAX_SAMPLES_NO	1024
+struct dn_pipe_max {
+	struct dn_pipe pipe;
+	int samples[ED_MAX_SAMPLES_NO];
+};
+
 SLIST_HEAD(dn_pipe_head, dn_pipe);
 
 #ifdef _KERNEL