Clean up

[dragonfly.git] / sys / net / dummynet / ip_dummynet.h

/*
 * 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: src/sys/netinet/ip_dummynet.h,v 1.10.2.9 2003/05/13 09:31:06 maxim Exp $
 * $DragonFly: src/sys/net/dummynet/ip_dummynet.h,v 1.10 2007/11/02 06:27:24 sephe Exp $
 */

#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 uint64_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/minimum hash table size for queues.
 * These values must be a power of 2.
 */
#define DN_MIN_HASH_SIZE        4
#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 */
};

#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)

/*
 * struct dn_pkt identifies a packet in the dummynet queue, but
 * is also used to tag packets passed back to the various destinations
 * (ip_input(), ip_output()  and so on).
 * It is a tag(PACKET_TAG_DUMMYNET) associated with the actual mbuf.
 */
struct dn_pkt {
    struct mbuf *dn_m;
    struct dn_pkt *dn_next;

    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
#define DN_TO_ETH_DEMUX 4
#define DN_TO_ETH_OUT   5

    dn_key output_time;         /* when the pkt is due for delivery */
    struct ifnet *ifp;          /* interface, for ip_output */
    struct sockaddr_in *dn_dst;
    struct route ro;            /* route, for ip_output. MUST COPY */
    int flags;                  /* flags, for ip_output (IPv6 ?) */
};

#endif

/*
 * 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 dn_pkt *head, *tail; /* queue of packets */
    u_int len;
    u_int len_bytes;
    u_long numbytes;            /* credit for transmission (dynamic queues) */

    uint64_t tot_pkts;          /* statistics counters */
    uint64_t tot_bytes;
    uint32_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) */
    uint32_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 {
    struct dn_flow_set *next;   /* next flow set in all_flow_sets list */

    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 */

    uint32_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 */
};

/*
 * 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 */
    struct dn_pipe *next;

    int pipe_nr;                /* number */
    int bandwidth;              /* really, bytes/tick. */
    int delay;                  /* really, ticks */

    struct dn_pkt *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 */
};

#ifdef _KERNEL
typedef int ip_dn_ctl_t(struct sockopt *); /* raw_ip.c */
typedef void ip_dn_ruledel_t(void *); /* ip_fw2.c */
typedef int ip_dn_io_t(struct mbuf *m, int pipe_nr, 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)
#endif

#endif /* !_IP_DUMMYNET_H */