7eef73ab3f
2) Alter packet flow inside dummynet: allow certain packets to bypass
dummynet scheduler. Benefits are:
- lower latency: if packet flow does not exceed pipe bandwidth, packets
will not be (up to tick) delayed (due to dummynet's scheduler granularity).
- lower overhead: if packet avoids dummynet scheduler it shouldn't reenter ip
stack later. Such packets can be fastforwarded.
- recursion (which can lead to kernel stack exhaution) eliminated. This fix
long existed panic, which can be triggered this way:
kldload dummynet
sysctl net.inet.ip.fw.one_pass=0
ipfw pipe 1 config bw 0
for i in `jot 30`; do ipfw add 1 pipe 1 icmp from any to any; done
ping -c 1 localhost
3) Three new sysctl nodes are added:
net.inet.ip.dummynet.io_pkt - packets passed to dummynet
net.inet.ip.dummynet.io_pkt_fast - packets avoided dummynet scheduler
net.inet.ip.dummynet.io_pkt_drop - packets dropped by dummynet
P.S. Above comments are true only for layer 3 packets. Layer 2 packet flow
is not changed yet.
MFC after: 3 month
368 lines
14 KiB
C
368 lines
14 KiB
C
/*-
|
|
* Copyright (c) 1998-2002 Luigi Rizzo, Universita` di Pisa
|
|
* Portions Copyright (c) 2000 Akamba Corp.
|
|
* All rights reserved
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#ifndef _IP_DUMMYNET_H
|
|
#define _IP_DUMMYNET_H
|
|
|
|
/*
|
|
* Definition of dummynet data structures. In the structures, I decided
|
|
* not to use the macros in <sys/queue.h> in the hope of making the code
|
|
* easier to port to other architectures. The type of lists and queue we
|
|
* use here is pretty simple anyways.
|
|
*/
|
|
|
|
/*
|
|
* We start with a heap, which is used in the scheduler to decide when
|
|
* to transmit packets etc.
|
|
*
|
|
* The key for the heap is used for two different values:
|
|
*
|
|
* 1. timer ticks- max 10K/second, so 32 bits are enough;
|
|
*
|
|
* 2. virtual times. These increase in steps of len/x, where len is the
|
|
* packet length, and x is either the weight of the flow, or the
|
|
* sum of all weights.
|
|
* If we limit to max 1000 flows and a max weight of 100, then
|
|
* x needs 17 bits. The packet size is 16 bits, so we can easily
|
|
* overflow if we do not allow errors.
|
|
* So we use a key "dn_key" which is 64 bits. Some macros are used to
|
|
* compare key values and handle wraparounds.
|
|
* MAX64 returns the largest of two key values.
|
|
* MY_M is used as a shift count when doing fixed point arithmetic
|
|
* (a better name would be useful...).
|
|
*/
|
|
typedef u_int64_t dn_key ; /* sorting key */
|
|
#define DN_KEY_LT(a,b) ((int64_t)((a)-(b)) < 0)
|
|
#define DN_KEY_LEQ(a,b) ((int64_t)((a)-(b)) <= 0)
|
|
#define DN_KEY_GT(a,b) ((int64_t)((a)-(b)) > 0)
|
|
#define DN_KEY_GEQ(a,b) ((int64_t)((a)-(b)) >= 0)
|
|
#define MAX64(x,y) (( (int64_t) ( (y)-(x) )) > 0 ) ? (y) : (x)
|
|
#define MY_M 16 /* number of left shift to obtain a larger precision */
|
|
|
|
/*
|
|
* XXX With this scaling, max 1000 flows, max weight 100, 1Gbit/s, the
|
|
* virtual time wraps every 15 days.
|
|
*/
|
|
|
|
|
|
/*
|
|
* The maximum hash table size for queues. This value must be a power
|
|
* of 2.
|
|
*/
|
|
#define DN_MAX_HASH_SIZE 65536
|
|
|
|
/*
|
|
* A heap entry is made of a key and a pointer to the actual
|
|
* object stored in the heap.
|
|
* The heap is an array of dn_heap_entry entries, dynamically allocated.
|
|
* Current size is "size", with "elements" actually in use.
|
|
* The heap normally supports only ordered insert and extract from the top.
|
|
* If we want to extract an object from the middle of the heap, we
|
|
* have to know where the object itself is located in the heap (or we
|
|
* need to scan the whole array). To this purpose, an object has a
|
|
* field (int) which contains the index of the object itself into the
|
|
* heap. When the object is moved, the field must also be updated.
|
|
* The offset of the index in the object is stored in the 'offset'
|
|
* field in the heap descriptor. The assumption is that this offset
|
|
* is non-zero if we want to support extract from the middle.
|
|
*/
|
|
struct dn_heap_entry {
|
|
dn_key key ; /* sorting key. Topmost element is smallest one */
|
|
void *object ; /* object pointer */
|
|
} ;
|
|
|
|
struct dn_heap {
|
|
int size ;
|
|
int elements ;
|
|
int offset ; /* XXX if > 0 this is the offset of direct ptr to obj */
|
|
struct dn_heap_entry *p ; /* really an array of "size" entries */
|
|
} ;
|
|
|
|
#ifdef _KERNEL
|
|
/*
|
|
* Packets processed by dummynet have an mbuf tag associated with
|
|
* them that carries their dummynet state. This is used within
|
|
* the dummynet code as well as outside when checking for special
|
|
* processing requirements.
|
|
*/
|
|
struct dn_pkt_tag {
|
|
struct ip_fw *rule; /* matching rule */
|
|
int dn_dir; /* action when packet comes out. */
|
|
#define DN_TO_IP_OUT 1
|
|
#define DN_TO_IP_IN 2
|
|
/* Obsolete: #define DN_TO_BDG_FWD 3 */
|
|
#define DN_TO_ETH_DEMUX 4
|
|
#define DN_TO_ETH_OUT 5
|
|
#define DN_TO_IP6_IN 6
|
|
#define DN_TO_IP6_OUT 7
|
|
#define DN_TO_IFB_FWD 8
|
|
|
|
dn_key output_time; /* when the pkt is due for delivery */
|
|
struct ifnet *ifp; /* interface, for ip_output */
|
|
struct _ip6dn_args ip6opt; /* XXX ipv6 options */
|
|
};
|
|
#endif /* _KERNEL */
|
|
|
|
/*
|
|
* Overall structure of dummynet (with WF2Q+):
|
|
|
|
In dummynet, packets are selected with the firewall rules, and passed
|
|
to two different objects: PIPE or QUEUE.
|
|
|
|
A QUEUE is just a queue with configurable size and queue management
|
|
policy. It is also associated with a mask (to discriminate among
|
|
different flows), a weight (used to give different shares of the
|
|
bandwidth to different flows) and a "pipe", which essentially
|
|
supplies the transmit clock for all queues associated with that
|
|
pipe.
|
|
|
|
A PIPE emulates a fixed-bandwidth link, whose bandwidth is
|
|
configurable. The "clock" for a pipe can come from either an
|
|
internal timer, or from the transmit interrupt of an interface.
|
|
A pipe is also associated with one (or more, if masks are used)
|
|
queue, where all packets for that pipe are stored.
|
|
|
|
The bandwidth available on the pipe is shared by the queues
|
|
associated with that pipe (only one in case the packet is sent
|
|
to a PIPE) according to the WF2Q+ scheduling algorithm and the
|
|
configured weights.
|
|
|
|
In general, incoming packets are stored in the appropriate queue,
|
|
which is then placed into one of a few heaps managed by a scheduler
|
|
to decide when the packet should be extracted.
|
|
The scheduler (a function called dummynet()) is run at every timer
|
|
tick, and grabs queues from the head of the heaps when they are
|
|
ready for processing.
|
|
|
|
There are three data structures definining a pipe and associated queues:
|
|
|
|
+ dn_pipe, which contains the main configuration parameters related
|
|
to delay and bandwidth;
|
|
+ dn_flow_set, which contains WF2Q+ configuration, flow
|
|
masks, plr and RED configuration;
|
|
+ dn_flow_queue, which is the per-flow queue (containing the packets)
|
|
|
|
Multiple dn_flow_set can be linked to the same pipe, and multiple
|
|
dn_flow_queue can be linked to the same dn_flow_set.
|
|
All data structures are linked in a linear list which is used for
|
|
housekeeping purposes.
|
|
|
|
During configuration, we create and initialize the dn_flow_set
|
|
and dn_pipe structures (a dn_pipe also contains a dn_flow_set).
|
|
|
|
At runtime: packets are sent to the appropriate dn_flow_set (either
|
|
WFQ ones, or the one embedded in the dn_pipe for fixed-rate flows),
|
|
which in turn dispatches them to the appropriate dn_flow_queue
|
|
(created dynamically according to the masks).
|
|
|
|
The transmit clock for fixed rate flows (ready_event()) selects the
|
|
dn_flow_queue to be used to transmit the next packet. For WF2Q,
|
|
wfq_ready_event() extract a pipe which in turn selects the right
|
|
flow using a number of heaps defined into the pipe itself.
|
|
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* per flow queue. This contains the flow identifier, the queue
|
|
* of packets, counters, and parameters used to support both RED and
|
|
* WF2Q+.
|
|
*
|
|
* A dn_flow_queue is created and initialized whenever a packet for
|
|
* a new flow arrives.
|
|
*/
|
|
struct dn_flow_queue {
|
|
struct dn_flow_queue *next ;
|
|
struct ipfw_flow_id id ;
|
|
|
|
struct mbuf *head, *tail ; /* queue of packets */
|
|
u_int len ;
|
|
u_int len_bytes ;
|
|
u_long numbytes ; /* credit for transmission (dynamic queues) */
|
|
|
|
u_int64_t tot_pkts ; /* statistics counters */
|
|
u_int64_t tot_bytes ;
|
|
u_int32_t drops ;
|
|
|
|
int hash_slot ; /* debugging/diagnostic */
|
|
|
|
/* RED parameters */
|
|
int avg ; /* average queue length est. (scaled) */
|
|
int count ; /* arrivals since last RED drop */
|
|
int random ; /* random value (scaled) */
|
|
u_int32_t q_time ; /* start of queue idle time */
|
|
|
|
/* WF2Q+ support */
|
|
struct dn_flow_set *fs ; /* parent flow set */
|
|
int heap_pos ; /* position (index) of struct in heap */
|
|
dn_key sched_time ; /* current time when queue enters ready_heap */
|
|
|
|
dn_key S,F ; /* start time, finish time */
|
|
/*
|
|
* Setting F < S means the timestamp is invalid. We only need
|
|
* to test this when the queue is empty.
|
|
*/
|
|
} ;
|
|
|
|
/*
|
|
* flow_set descriptor. Contains the "template" parameters for the
|
|
* queue configuration, and pointers to the hash table of dn_flow_queue's.
|
|
*
|
|
* The hash table is an array of lists -- we identify the slot by
|
|
* hashing the flow-id, then scan the list looking for a match.
|
|
* The size of the hash table (buckets) is configurable on a per-queue
|
|
* basis.
|
|
*
|
|
* A dn_flow_set is created whenever a new queue or pipe is created (in the
|
|
* latter case, the structure is located inside the struct dn_pipe).
|
|
*/
|
|
struct dn_flow_set {
|
|
SLIST_ENTRY(dn_flow_set) next; /* linked list in a hash slot */
|
|
|
|
u_short fs_nr ; /* flow_set number */
|
|
u_short flags_fs;
|
|
#define DN_HAVE_FLOW_MASK 0x0001
|
|
#define DN_IS_RED 0x0002
|
|
#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_IS_PIPE 0x4000
|
|
#define DN_IS_QUEUE 0x8000
|
|
|
|
struct dn_pipe *pipe ; /* pointer to parent pipe */
|
|
u_short parent_nr ; /* parent pipe#, 0 if local to a pipe */
|
|
|
|
int weight ; /* WFQ queue weight */
|
|
int qsize ; /* queue size in slots or bytes */
|
|
int plr ; /* pkt loss rate (2^31-1 means 100%) */
|
|
|
|
struct ipfw_flow_id flow_mask ;
|
|
|
|
/* hash table of queues onto this flow_set */
|
|
int rq_size ; /* number of slots */
|
|
int rq_elements ; /* active elements */
|
|
struct dn_flow_queue **rq; /* array of rq_size entries */
|
|
|
|
u_int32_t last_expired ; /* do not expire too frequently */
|
|
int backlogged ; /* #active queues for this flowset */
|
|
|
|
/* RED parameters */
|
|
#define SCALE_RED 16
|
|
#define SCALE(x) ( (x) << SCALE_RED )
|
|
#define SCALE_VAL(x) ( (x) >> SCALE_RED )
|
|
#define SCALE_MUL(x,y) ( ( (x) * (y) ) >> SCALE_RED )
|
|
int w_q ; /* queue weight (scaled) */
|
|
int max_th ; /* maximum threshold for queue (scaled) */
|
|
int min_th ; /* minimum threshold for queue (scaled) */
|
|
int max_p ; /* maximum value for p_b (scaled) */
|
|
u_int c_1 ; /* max_p/(max_th-min_th) (scaled) */
|
|
u_int c_2 ; /* max_p*min_th/(max_th-min_th) (scaled) */
|
|
u_int c_3 ; /* for GRED, (1-max_p)/max_th (scaled) */
|
|
u_int c_4 ; /* for GRED, 1 - 2*max_p (scaled) */
|
|
u_int * w_q_lookup ; /* lookup table for computing (1-w_q)^t */
|
|
u_int lookup_depth ; /* depth of lookup table */
|
|
int lookup_step ; /* granularity inside the lookup table */
|
|
int lookup_weight ; /* equal to (1-w_q)^t / (1-w_q)^(t+1) */
|
|
int avg_pkt_size ; /* medium packet size */
|
|
int max_pkt_size ; /* max packet size */
|
|
};
|
|
SLIST_HEAD(dn_flow_set_head, dn_flow_set);
|
|
|
|
/*
|
|
* Pipe descriptor. Contains global parameters, delay-line queue,
|
|
* and the flow_set used for fixed-rate queues.
|
|
*
|
|
* For WF2Q+ support it also has 3 heaps holding dn_flow_queue:
|
|
* not_eligible_heap, for queues whose start time is higher
|
|
* than the virtual time. Sorted by start time.
|
|
* scheduler_heap, for queues eligible for scheduling. Sorted by
|
|
* finish time.
|
|
* idle_heap, all flows that are idle and can be removed. We
|
|
* do that on each tick so we do not slow down too much
|
|
* operations during forwarding.
|
|
*
|
|
*/
|
|
struct dn_pipe { /* a pipe */
|
|
SLIST_ENTRY(dn_pipe) next; /* linked list in a hash slot */
|
|
|
|
int pipe_nr ; /* number */
|
|
int bandwidth; /* really, bytes/tick. */
|
|
int delay ; /* really, ticks */
|
|
|
|
struct mbuf *head, *tail ; /* packets in delay line */
|
|
|
|
/* WF2Q+ */
|
|
struct dn_heap scheduler_heap ; /* top extract - key Finish time*/
|
|
struct dn_heap not_eligible_heap; /* top extract- key Start time */
|
|
struct dn_heap idle_heap ; /* random extract - key Start=Finish time */
|
|
|
|
dn_key V ; /* virtual time */
|
|
int sum; /* sum of weights of all active sessions */
|
|
int numbytes; /* bits I can transmit (more or less). */
|
|
|
|
dn_key sched_time ; /* time pipe was scheduled in ready_heap */
|
|
|
|
/*
|
|
* When the tx clock come from an interface (if_name[0] != '\0'), its name
|
|
* is stored below, whereas the ifp is filled when the rule is configured.
|
|
*/
|
|
char if_name[IFNAMSIZ];
|
|
struct ifnet *ifp ;
|
|
int ready ; /* set if ifp != NULL and we got a signal from it */
|
|
|
|
struct dn_flow_set fs ; /* used with fixed-rate flows */
|
|
};
|
|
SLIST_HEAD(dn_pipe_head, dn_pipe);
|
|
|
|
#ifdef _KERNEL
|
|
typedef int ip_dn_ctl_t(struct sockopt *); /* raw_ip.c */
|
|
typedef void ip_dn_ruledel_t(void *); /* ip_fw.c */
|
|
typedef int ip_dn_io_t(struct mbuf **m, int dir, struct ip_fw_args *fwa);
|
|
extern ip_dn_ctl_t *ip_dn_ctl_ptr;
|
|
extern ip_dn_ruledel_t *ip_dn_ruledel_ptr;
|
|
extern ip_dn_io_t *ip_dn_io_ptr;
|
|
#define DUMMYNET_LOADED (ip_dn_io_ptr != NULL)
|
|
|
|
/*
|
|
* Return the IPFW rule associated with the dummynet tag; if any.
|
|
* Make sure that the dummynet tag is not reused by lower layers.
|
|
*/
|
|
static __inline struct ip_fw *
|
|
ip_dn_claim_rule(struct mbuf *m)
|
|
{
|
|
struct m_tag *mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
|
|
if (mtag != NULL) {
|
|
mtag->m_tag_id = PACKET_TAG_NONE;
|
|
return (((struct dn_pkt_tag *)(mtag+1))->rule);
|
|
} else
|
|
return (NULL);
|
|
}
|
|
#endif
|
|
#endif /* _IP_DUMMYNET_H */
|