/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2018 Universita` di Pisa
 * 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.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <net/netmap_user.h>
#define LIBNETMAP_NOTHREADSAFE
#include "libnetmap.h"

struct nmport_cleanup_d {
        struct nmport_cleanup_d *next;
        void (*cleanup)(struct nmport_cleanup_d *, struct nmport_d *);
};

static void
nmport_push_cleanup(struct nmport_d *d, struct nmport_cleanup_d *c)
{
        c->next = d->clist;
        d->clist = c;
}

static void
nmport_pop_cleanup(struct nmport_d *d)
{
        struct nmport_cleanup_d *top;

        top = d->clist;
        d->clist = d->clist->next;
        (*top->cleanup)(top, d);
        nmctx_free(d->ctx, top);
}

void nmport_do_cleanup(struct nmport_d *d)
{
        while (d->clist != NULL) {
                nmport_pop_cleanup(d);
        }
}

static struct nmport_d *
nmport_new_with_ctx(struct nmctx *ctx)
{
        struct nmport_d *d;

        /* allocate a descriptor */
        d = nmctx_malloc(ctx, sizeof(*d));
        if (d == NULL) {
                nmctx_ferror(ctx, "cannot allocate nmport descriptor");
                goto out;
        }
        memset(d, 0, sizeof(*d));

        nmreq_header_init(&d->hdr, NETMAP_REQ_REGISTER, &d->reg);

        d->ctx = ctx;
        d->fd = -1;

out:
        return d;
}

struct nmport_d *
nmport_new(void)
{
        struct nmctx *ctx = nmctx_get();
        return nmport_new_with_ctx(ctx);
}


void
nmport_delete(struct nmport_d *d)
{
        nmctx_free(d->ctx, d);
}

void
nmport_extmem_cleanup(struct nmport_cleanup_d *c, struct nmport_d *d)
{
        (void)c;

        if (d->extmem == NULL)
                return;

        nmreq_remove_option(&d->hdr, &d->extmem->nro_opt);
        nmctx_free(d->ctx, d->extmem);
        d->extmem = NULL;
}


int
nmport_extmem(struct nmport_d *d, void *base, size_t size)
{
        struct nmctx *ctx = d->ctx;
        struct nmport_cleanup_d *clnup = NULL;

        if (d->register_done) {
                nmctx_ferror(ctx, "%s: cannot set extmem of an already registered port", d->hdr.nr_name);
                errno = EINVAL;
                return -1;
        }

        if (d->extmem != NULL) {
                nmctx_ferror(ctx, "%s: extmem already in use", d->hdr.nr_name);
                errno = EINVAL;
                return -1;
        }

        clnup = (struct nmport_cleanup_d *)nmctx_malloc(ctx, sizeof(*clnup));
        if (clnup == NULL) {
                nmctx_ferror(ctx, "failed to allocate cleanup descriptor");
                errno = ENOMEM;
                return -1;
        }

        d->extmem = nmctx_malloc(ctx, sizeof(*d->extmem));
        if (d->extmem == NULL) {
                nmctx_ferror(ctx, "%s: cannot allocate extmem option", d->hdr.nr_name);
                nmctx_free(ctx, clnup);
                errno = ENOMEM;
                return -1;
        }
        memset(d->extmem, 0, sizeof(*d->extmem));
        d->extmem->nro_usrptr = (uintptr_t)base;
        d->extmem->nro_opt.nro_reqtype = NETMAP_REQ_OPT_EXTMEM;
        d->extmem->nro_info.nr_memsize = size;
        nmreq_push_option(&d->hdr, &d->extmem->nro_opt);

        clnup->cleanup = nmport_extmem_cleanup;
        nmport_push_cleanup(d, clnup);

        return 0;
}

struct nmport_extmem_from_file_cleanup_d {
        struct nmport_cleanup_d up;
        void *p;
        size_t size;
};

void nmport_extmem_from_file_cleanup(struct nmport_cleanup_d *c,
                struct nmport_d *d)
{
        (void)d;
        struct nmport_extmem_from_file_cleanup_d *cc =
                (struct nmport_extmem_from_file_cleanup_d *)c;

        munmap(cc->p, cc->size);
}

int
nmport_extmem_from_file(struct nmport_d *d, const char *fname)
{
        struct nmctx *ctx = d->ctx;
        int fd = -1;
        off_t mapsize;
        void *p;
        struct nmport_extmem_from_file_cleanup_d *clnup = NULL;

        clnup = nmctx_malloc(ctx, sizeof(*clnup));
        if (clnup == NULL) {
                nmctx_ferror(ctx, "cannot allocate cleanup descriptor");
                errno = ENOMEM;
                goto fail;
        }

        fd = open(fname, O_RDWR);
        if (fd < 0) {
                nmctx_ferror(ctx, "cannot open '%s': %s", fname, strerror(errno));
                goto fail;
        }
        mapsize = lseek(fd, 0, SEEK_END);
        if (mapsize < 0) {
                nmctx_ferror(ctx, "failed to obtain filesize of '%s': %s", fname, strerror(errno));
                goto fail;
        }
        p = mmap(0, mapsize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
        if (p == MAP_FAILED) {
                nmctx_ferror(ctx, "cannot mmap '%s': %s", fname, strerror(errno));
                goto fail;
        }
        close(fd);

        clnup->p = p;
        clnup->size = mapsize;
        clnup->up.cleanup = nmport_extmem_from_file_cleanup;
        nmport_push_cleanup(d, &clnup->up);

        if (nmport_extmem(d, p, mapsize) < 0)
                goto fail;

        return 0;

fail:
        if (fd >= 0)
                close(fd);
        if (clnup != NULL) {
                if (clnup->p != MAP_FAILED)
                        nmport_pop_cleanup(d);
                else
                        nmctx_free(ctx, clnup);
        }
        return -1;
}

struct nmreq_pools_info*
nmport_extmem_getinfo(struct nmport_d *d)
{
        if (d->extmem == NULL)
                return NULL;
        return &d->extmem->nro_info;
}

struct nmport_offset_cleanup_d {
        struct nmport_cleanup_d up;
        struct nmreq_opt_offsets *opt;
};

static void
nmport_offset_cleanup(struct nmport_cleanup_d *c,
                struct nmport_d *d)
{
        struct nmport_offset_cleanup_d *cc =
                (struct nmport_offset_cleanup_d *)c;

        nmreq_remove_option(&d->hdr, &cc->opt->nro_opt);
        nmctx_free(d->ctx, cc->opt);
}

int
nmport_offset(struct nmport_d *d, uint64_t initial,
                uint64_t maxoff, uint64_t bits, uint64_t mingap)
{
        struct nmctx *ctx = d->ctx;
        struct nmreq_opt_offsets *opt;
        struct nmport_offset_cleanup_d *clnup = NULL;

        clnup = nmctx_malloc(ctx, sizeof(*clnup));
        if (clnup == NULL) {
                nmctx_ferror(ctx, "cannot allocate cleanup descriptor");
                errno = ENOMEM;
                return -1;
        }

        opt = nmctx_malloc(ctx, sizeof(*opt));
        if (opt == NULL) {
                nmctx_ferror(ctx, "%s: cannot allocate offset option", d->hdr.nr_name);
                nmctx_free(ctx, clnup);
                errno = ENOMEM;
                return -1;
        }
        memset(opt, 0, sizeof(*opt));
        opt->nro_opt.nro_reqtype = NETMAP_REQ_OPT_OFFSETS;
        opt->nro_offset_bits = bits;
        opt->nro_initial_offset = initial;
        opt->nro_max_offset = maxoff;
        opt->nro_min_gap = mingap;
        nmreq_push_option(&d->hdr, &opt->nro_opt);

        clnup->up.cleanup = nmport_offset_cleanup;
        clnup->opt = opt;
        nmport_push_cleanup(d, &clnup->up);

        return 0;
}

/* head of the list of options */
static struct nmreq_opt_parser *nmport_opt_parsers;

#define NPOPT_PARSER(o)         nmport_opt_##o##_parser
#define NPOPT_DESC(o)           nmport_opt_##o##_desc
#define NPOPT_NRKEYS(o)         (NPOPT_DESC(o).nr_keys)
#define NPOPT_DECL(o, f)                                                \
static int NPOPT_PARSER(o)(struct nmreq_parse_ctx *);                   \
static struct nmreq_opt_parser NPOPT_DESC(o) = {                        \
        .prefix = #o,                                                   \
        .parse = NPOPT_PARSER(o),                                       \
        .flags = (f),                                                   \
        .default_key = -1,                                              \
        .nr_keys = 0,                                                   \
        .next = NULL,                                                   \
};                                                                      \
static void __attribute__((constructor))                                \
nmport_opt_##o##_ctor(void)                                             \
{                                                                       \
        NPOPT_DESC(o).next = nmport_opt_parsers;                        \
        nmport_opt_parsers = &NPOPT_DESC(o);                            \
}
struct nmport_key_desc {
        struct nmreq_opt_parser *option;
        const char *key;
        unsigned int flags;
        int id;
};
static void
nmport_opt_key_ctor(struct nmport_key_desc *k)
{
        struct nmreq_opt_parser *o = k->option;
        struct nmreq_opt_key *ok;

        k->id = o->nr_keys;
        ok = &o->keys[k->id];
        ok->key = k->key;
        ok->id = k->id;
        ok->flags = k->flags;
        o->nr_keys++;
        if (ok->flags & NMREQ_OPTK_DEFAULT)
                o->default_key = ok->id;
}
#define NPKEY_DESC(o, k)        nmport_opt_##o##_key_##k##_desc
#define NPKEY_ID(o, k)          (NPKEY_DESC(o, k).id)
#define NPKEY_DECL(o, k, f)                                             \
static struct nmport_key_desc NPKEY_DESC(o, k) = {                      \
        .option = &NPOPT_DESC(o),                                       \
        .key = #k,                                                      \
        .flags = (f),                                                   \
        .id = -1,                                                       \
};                                                                      \
static void __attribute__((constructor))                                \
nmport_opt_##o##_key_##k##_ctor(void)                                   \
{                                                                       \
        nmport_opt_key_ctor(&NPKEY_DESC(o, k));                         \
}
#define nmport_key(p, o, k)     ((p)->keys[NPKEY_ID(o, k)])
#define nmport_defkey(p, o)     ((p)->keys[NPOPT_DESC(o).default_key])

NPOPT_DECL(share, 0)
        NPKEY_DECL(share, port, NMREQ_OPTK_DEFAULT|NMREQ_OPTK_MUSTSET)
NPOPT_DECL(extmem, 0)
        NPKEY_DECL(extmem, file, NMREQ_OPTK_DEFAULT|NMREQ_OPTK_MUSTSET)
        NPKEY_DECL(extmem, if_num, 0)
        NPKEY_DECL(extmem, if_size, 0)
        NPKEY_DECL(extmem, ring_num, 0)
        NPKEY_DECL(extmem, ring_size, 0)
        NPKEY_DECL(extmem, buf_num, 0)
        NPKEY_DECL(extmem, buf_size, 0)
NPOPT_DECL(conf, 0)
        NPKEY_DECL(conf, rings, 0)
        NPKEY_DECL(conf, host_rings, 0)
        NPKEY_DECL(conf, slots, 0)
        NPKEY_DECL(conf, tx_rings, 0)
        NPKEY_DECL(conf, rx_rings, 0)
        NPKEY_DECL(conf, host_tx_rings, 0)
        NPKEY_DECL(conf, host_rx_rings, 0)
        NPKEY_DECL(conf, tx_slots, 0)
        NPKEY_DECL(conf, rx_slots, 0)
NPOPT_DECL(offset, NMREQ_OPTF_DISABLED)
        NPKEY_DECL(offset, initial, NMREQ_OPTK_DEFAULT|NMREQ_OPTK_MUSTSET)
        NPKEY_DECL(offset, bits, 0)


static int
NPOPT_PARSER(share)(struct nmreq_parse_ctx *p)
{
        struct nmctx *ctx = p->ctx;
        struct nmport_d *d = p->token;
        int32_t mem_id;
        const char *v = nmport_defkey(p, share);

        mem_id = nmreq_get_mem_id(&v, ctx);
        if (mem_id < 0)
                return -1;
        if (d->reg.nr_mem_id && d->reg.nr_mem_id != mem_id) {
                nmctx_ferror(ctx, "cannot set mem_id to %"PRId32", already set to %"PRIu16"",
                                mem_id, d->reg.nr_mem_id);
                errno = EINVAL;
                return -1;
        }
        d->reg.nr_mem_id = mem_id;
        return 0;
}

static int
NPOPT_PARSER(extmem)(struct nmreq_parse_ctx *p)
{
        struct nmport_d *d;
        struct nmreq_pools_info *pi;
        int i;

        d = p->token;

        if (nmport_extmem_from_file(d, nmport_key(p, extmem, file)) < 0)
                return -1;

        pi = &d->extmem->nro_info;

        for  (i = 0; i < NPOPT_NRKEYS(extmem); i++) {
                const char *k = p->keys[i];
                uint32_t v;

                if (k == NULL)
                        continue;

                v = atoi(k);
                if (i == NPKEY_ID(extmem, if_num)) {
                        pi->nr_if_pool_objtotal = v;
                } else if (i == NPKEY_ID(extmem, if_size)) {
                        pi->nr_if_pool_objsize = v;
                } else if (i == NPKEY_ID(extmem, ring_num)) {
                        pi->nr_ring_pool_objtotal = v;
                } else if (i == NPKEY_ID(extmem, ring_size)) {
                        pi->nr_ring_pool_objsize = v;
                } else if (i == NPKEY_ID(extmem, buf_num)) {
                        pi->nr_buf_pool_objtotal = v;
                } else if (i == NPKEY_ID(extmem, buf_size)) {
                        pi->nr_buf_pool_objsize = v;
                }
        }
        return 0;
}

static int
NPOPT_PARSER(conf)(struct nmreq_parse_ctx *p)
{
        struct nmport_d *d;

        d = p->token;

        if (nmport_key(p, conf, rings) != NULL) {
                uint16_t nr_rings = atoi(nmport_key(p, conf, rings));
                d->reg.nr_tx_rings = nr_rings;
                d->reg.nr_rx_rings = nr_rings;
        }
        if (nmport_key(p, conf, host_rings) != NULL) {
                uint16_t nr_rings = atoi(nmport_key(p, conf, host_rings));
                d->reg.nr_host_tx_rings = nr_rings;
                d->reg.nr_host_rx_rings = nr_rings;
        }
        if (nmport_key(p, conf, slots) != NULL) {
                uint32_t nr_slots = atoi(nmport_key(p, conf, slots));
                d->reg.nr_tx_slots = nr_slots;
                d->reg.nr_rx_slots = nr_slots;
        }
        if (nmport_key(p, conf, tx_rings) != NULL) {
                d->reg.nr_tx_rings = atoi(nmport_key(p, conf, tx_rings));
        }
        if (nmport_key(p, conf, rx_rings) != NULL) {
                d->reg.nr_rx_rings = atoi(nmport_key(p, conf, rx_rings));
        }
        if (nmport_key(p, conf, host_tx_rings) != NULL) {
                d->reg.nr_host_tx_rings = atoi(nmport_key(p, conf, host_tx_rings));
        }
        if (nmport_key(p, conf, host_rx_rings) != NULL) {
                d->reg.nr_host_rx_rings = atoi(nmport_key(p, conf, host_rx_rings));
        }
        if (nmport_key(p, conf, tx_slots) != NULL) {
                d->reg.nr_tx_slots = atoi(nmport_key(p, conf, tx_slots));
        }
        if (nmport_key(p, conf, rx_slots) != NULL) {
                d->reg.nr_rx_slots = atoi(nmport_key(p, conf, rx_slots));
        }
        return 0;
}

static int
NPOPT_PARSER(offset)(struct nmreq_parse_ctx *p)
{
        struct nmport_d *d;
        uint64_t initial, bits;

        d = p->token;

        initial = atoi(nmport_key(p, offset, initial));
        bits = 0;
        if (nmport_key(p, offset, bits) != NULL)
                bits = atoi(nmport_key(p, offset, bits));

        return nmport_offset(d, initial, initial, bits, 0);
}


void
nmport_disable_option(const char *opt)
{
        struct nmreq_opt_parser *p;

        for (p = nmport_opt_parsers; p != NULL; p = p->next) {
                if (!strcmp(p->prefix, opt)) {
                        p->flags |= NMREQ_OPTF_DISABLED;
                }
        }
}

int
nmport_enable_option(const char *opt)
{
        struct nmreq_opt_parser *p;

        for (p = nmport_opt_parsers; p != NULL; p = p->next) {
                if (!strcmp(p->prefix, opt)) {
                        p->flags &= ~NMREQ_OPTF_DISABLED;
                        return 0;
                }
        }
        errno = EOPNOTSUPP;
        return -1;
}


int
nmport_parse(struct nmport_d *d, const char *ifname)
{
        const char *scan = ifname;

        if (nmreq_header_decode(&scan, &d->hdr, d->ctx) < 0) {
                goto err;
        }

        /* parse the register request */
        if (nmreq_register_decode(&scan, &d->reg, d->ctx) < 0) {
                goto err;
        }

        /* parse the options, if any */
        if (nmreq_options_decode(scan, nmport_opt_parsers, d, d->ctx) < 0) {
                goto err;
        }
        return 0;

err:
        nmport_undo_parse(d);
        return -1;
}

void
nmport_undo_parse(struct nmport_d *d)
{
        nmport_do_cleanup(d);
        memset(&d->reg, 0, sizeof(d->reg));
        memset(&d->hdr, 0, sizeof(d->hdr));
}

struct nmport_d *
nmport_prepare(const char *ifname)
{
        struct nmport_d *d;

        /* allocate a descriptor */
        d = nmport_new();
        if (d == NULL)
                goto err;

        /* parse the header */
        if (nmport_parse(d, ifname) < 0)
                goto err;

        return d;

err:
        nmport_undo_prepare(d);
        return NULL;
}

void
nmport_undo_prepare(struct nmport_d *d)
{
        if (d == NULL)
                return;
        nmport_undo_parse(d);
        nmport_delete(d);
}

int
nmport_register(struct nmport_d *d)
{
        struct nmctx *ctx = d->ctx;

        if (d->register_done) {
                errno = EINVAL;
                nmctx_ferror(ctx, "%s: already registered", d->hdr.nr_name);
                return -1;
        }

        d->fd = open("/dev/netmap", O_RDWR);
        if (d->fd < 0) {
                nmctx_ferror(ctx, "/dev/netmap: %s", strerror(errno));
                goto err;
        }

        if (ioctl(d->fd, NIOCCTRL, &d->hdr) < 0) {
                struct nmreq_option *o;
                int option_errors = 0;

                nmreq_foreach_option(&d->hdr, o) {
                        if (o->nro_status) {
                                nmctx_ferror(ctx, "%s: option %s: %s",
                                                d->hdr.nr_name,
                                                nmreq_option_name(o->nro_reqtype),
                                                strerror(o->nro_status));
                                option_errors++;
                        }

                }
                if (!option_errors)
                        nmctx_ferror(ctx, "%s: %s", d->hdr.nr_name, strerror(errno));
                goto err;
        }

        d->register_done = 1;

        return 0;

err:
        nmport_undo_register(d);
        return -1;
}

void
nmport_undo_register(struct nmport_d *d)
{
        if (d->fd >= 0)
                close(d->fd);
        d->fd = -1;
        d->register_done = 0;
}

/* lookup the mem_id in the mem-list: do a new mmap() if
 * not found, reuse existing otherwise
 */
int
nmport_mmap(struct nmport_d *d)
{
        struct nmctx *ctx = d->ctx;
        struct nmem_d *m = NULL;
        u_int num_tx, num_rx;
        unsigned int i;

        if (d->mmap_done) {
                errno = EINVAL;
                nmctx_ferror(ctx, "%s: already mapped", d->hdr.nr_name);
                return -1;
        }

        if (!d->register_done) {
                errno = EINVAL;
                nmctx_ferror(ctx, "cannot map unregistered port");
                return -1;
        }

        nmctx_lock(ctx);

        for (m = ctx->mem_descs; m != NULL; m = m->next)
                if (m->mem_id == d->reg.nr_mem_id)
                        break;

        if (m == NULL) {
                m = nmctx_malloc(ctx, sizeof(*m));
                if (m == NULL) {
                        nmctx_ferror(ctx, "cannot allocate memory descriptor");
                        goto err;
                }
                memset(m, 0, sizeof(*m));
                if (d->extmem != NULL) {
                        m->mem = (void *)((uintptr_t)d->extmem->nro_usrptr);
                        m->size = d->extmem->nro_info.nr_memsize;
                        m->is_extmem = 1;
                } else {
                        m->mem = mmap(NULL, d->reg.nr_memsize, PROT_READ|PROT_WRITE,
                                        MAP_SHARED, d->fd, 0);
                        if (m->mem == MAP_FAILED) {
                                nmctx_ferror(ctx, "mmap: %s", strerror(errno));
                                goto err;
                        }
                        m->size = d->reg.nr_memsize;
                }
                m->mem_id = d->reg.nr_mem_id;
                m->next = ctx->mem_descs;
                if (ctx->mem_descs != NULL)
                        ctx->mem_descs->prev = m;
                ctx->mem_descs = m;
        }
        m->refcount++;

        nmctx_unlock(ctx);

        d->mem = m;

        d->nifp = NETMAP_IF(m->mem, d->reg.nr_offset);

        num_tx = d->reg.nr_tx_rings + d->nifp->ni_host_tx_rings;
        for (i = 0; i < num_tx && !d->nifp->ring_ofs[i]; i++)
                ;
        d->cur_tx_ring = d->first_tx_ring = i;
        for ( ; i < num_tx && d->nifp->ring_ofs[i]; i++)
                ;
        d->last_tx_ring = i - 1;

        num_rx = d->reg.nr_rx_rings + d->nifp->ni_host_rx_rings;
        for (i = 0; i < num_rx && !d->nifp->ring_ofs[i + num_tx]; i++)
                ;
        d->cur_rx_ring = d->first_rx_ring = i;
        for ( ; i < num_rx && d->nifp->ring_ofs[i + num_tx]; i++)
                ;
        d->last_rx_ring = i - 1;

        d->mmap_done = 1;

        return 0;

err:
        nmctx_unlock(ctx);
        nmport_undo_mmap(d);
        return -1;
}

void
nmport_undo_mmap(struct nmport_d *d)
{
        struct nmem_d *m;
        struct nmctx *ctx = d->ctx;

        m = d->mem;
        if (m == NULL)
                return;
        nmctx_lock(ctx);
        m->refcount--;
        if (m->refcount <= 0) {
                if (!m->is_extmem && m->mem != MAP_FAILED)
                        munmap(m->mem, m->size);
                /* extract from the list and free */
                if (m->next != NULL)
                        m->next->prev = m->prev;
                if (m->prev != NULL)
                        m->prev->next = m->next;
                else
                        ctx->mem_descs = m->next;
                nmctx_free(ctx, m);
                d->mem = NULL;
        }
        nmctx_unlock(ctx);
        d->mmap_done = 0;
        d->mem = NULL;
        d->nifp = NULL;
        d->first_tx_ring = 0;
        d->last_tx_ring = 0;
        d->first_rx_ring = 0;
        d->last_rx_ring = 0;
        d->cur_tx_ring = 0;
        d->cur_rx_ring = 0;
}

int
nmport_open_desc(struct nmport_d *d)
{
        if (nmport_register(d) < 0)
                goto err;

        if (nmport_mmap(d) < 0)
                goto err;

        return 0;
err:
        nmport_undo_open_desc(d);
        return -1;
}

void
nmport_undo_open_desc(struct nmport_d *d)
{
        nmport_undo_mmap(d);
        nmport_undo_register(d);
}


struct nmport_d *
nmport_open(const char *ifname)
{
        struct nmport_d *d;

        /* prepare the descriptor */
        d = nmport_prepare(ifname);
        if (d == NULL)
                goto err;

        /* open netmap and register */
        if (nmport_open_desc(d) < 0)
                goto err;

        return d;

err:
        nmport_close(d);
        return NULL;
}

void
nmport_close(struct nmport_d *d)
{
        if (d == NULL)
                return;
        nmport_undo_open_desc(d);
        nmport_undo_prepare(d);
}

struct nmport_d *
nmport_clone(struct nmport_d *d)
{
        struct nmport_d *c;
        struct nmctx *ctx;

        ctx = d->ctx;

        if (d->extmem != NULL && !d->register_done) {
                errno = EINVAL;
                nmctx_ferror(ctx, "cannot clone unregistered port that is using extmem");
                return NULL;
        }

        c = nmport_new_with_ctx(ctx);
        if (c == NULL)
                return NULL;
        /* copy the output of parse */
        c->hdr = d->hdr;
        /* redirect the pointer to the body */
        c->hdr.nr_body = (uintptr_t)&c->reg;
        /* options are not cloned */
        c->hdr.nr_options = 0;
        c->reg = d->reg; /* this also copies the mem_id */
        /* put the new port in an un-registered, unmapped state */
        c->fd = -1;
        c->nifp = NULL;
        c->register_done = 0;
        c->mem = NULL;
        c->extmem = NULL;
        c->mmap_done = 0;
        c->first_tx_ring = 0;
        c->last_tx_ring = 0;
        c->first_rx_ring = 0;
        c->last_rx_ring = 0;
        c->cur_tx_ring = 0;
        c->cur_rx_ring = 0;

        return c;
}

int
nmport_inject(struct nmport_d *d, const void *buf, size_t size)
{
        u_int c, n = d->last_tx_ring - d->first_tx_ring + 1,
                ri = d->cur_tx_ring;

        for (c = 0; c < n ; c++, ri++) {
                /* compute current ring to use */
                struct netmap_ring *ring;
                uint32_t i, j, idx;
                size_t rem;

                if (ri > d->last_tx_ring)
                        ri = d->first_tx_ring;
                ring = NETMAP_TXRING(d->nifp, ri);
                rem = size;
                j = ring->cur;
                while (rem > ring->nr_buf_size && j != ring->tail) {
                        rem -= ring->nr_buf_size;
                        j = nm_ring_next(ring, j);
                }
                if (j == ring->tail && rem > 0)
                        continue;
                i = ring->cur;
                while (i != j) {
                        idx = ring->slot[i].buf_idx;
                        ring->slot[i].len = ring->nr_buf_size;
                        ring->slot[i].flags = NS_MOREFRAG;
                        nm_pkt_copy(buf, NETMAP_BUF(ring, idx), ring->nr_buf_size);
                        i = nm_ring_next(ring, i);
                        buf = (char *)buf + ring->nr_buf_size;
                }
                idx = ring->slot[i].buf_idx;
                ring->slot[i].len = rem;
                ring->slot[i].flags = 0;
                nm_pkt_copy(buf, NETMAP_BUF(ring, idx), rem);
                ring->head = ring->cur = nm_ring_next(ring, i);
                d->cur_tx_ring = ri;
                return size;
        }
        return 0; /* fail */
}