/*-
 * 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 <ctype.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>

//#define NMREQ_DEBUG
#ifdef NMREQ_DEBUG
#define NETMAP_WITH_LIBS
#define ED(...) D(__VA_ARGS__)
#else
#define ED(...)
/* an identifier is a possibly empty sequence of alphanum characters and
 * underscores
 */
static int
nm_is_identifier(const char *s, const char *e)
{
        for (; s != e; s++) {
                if (!isalnum(*s) && *s != '_') {
                        return 0;
                }
        }

        return 1;
}
#endif /* NMREQ_DEBUG */

#include <net/netmap_user.h>
#define LIBNETMAP_NOTHREADSAFE
#include "libnetmap.h"

void
nmreq_push_option(struct nmreq_header *h, struct nmreq_option *o)
{
        o->nro_next = h->nr_options;
        h->nr_options = (uintptr_t)o;
}

struct nmreq_prefix {
        const char *prefix;             /* the constant part of the prefix */
        size_t      len;                /* its strlen() */
        uint32_t    flags;
#define NR_P_ID         (1U << 0)       /* whether an identifier is needed */
#define NR_P_SKIP       (1U << 1)       /* whether the scope must be passed to netmap */
#define NR_P_EMPTYID    (1U << 2)       /* whether an empty identifier is allowed */
};

#define declprefix(prefix, flags)       { (prefix), (sizeof(prefix) - 1), (flags) }

static struct nmreq_prefix nmreq_prefixes[] = {
        declprefix("netmap", NR_P_SKIP),
        declprefix(NM_BDG_NAME, NR_P_ID|NR_P_EMPTYID),
        { NULL } /* terminate the list */
};

void
nmreq_header_init(struct nmreq_header *h, uint16_t reqtype, void *body)
{
        memset(h, 0, sizeof(*h));
        h->nr_version = NETMAP_API;
        h->nr_reqtype = reqtype;
        h->nr_body = (uintptr_t)body;
}

int
nmreq_header_decode(const char **pifname, struct nmreq_header *h, struct nmctx *ctx)
{
        const char *scan = NULL;
        const char *vpname = NULL;
        const char *pipesep = NULL;
        u_int namelen;
        const char *ifname = *pifname;
        struct nmreq_prefix *p;

        scan = ifname;
        for (p = nmreq_prefixes; p->prefix != NULL; p++) {
                if (!strncmp(scan, p->prefix, p->len))
                        break;
        }
        if (p->prefix == NULL) {
                nmctx_ferror(ctx, "%s: invalid request, prefix unknown or missing", *pifname);
                goto fail;
        }
        scan += p->len;

        vpname = index(scan, ':');
        if (vpname == NULL) {
                nmctx_ferror(ctx, "%s: missing ':'", ifname);
                goto fail;
        }
        if (vpname != scan) {
                /* there is an identifier, can we accept it? */
                if (!(p->flags & NR_P_ID)) {
                        nmctx_ferror(ctx, "%s: no identifier allowed between '%s' and ':'", *pifname, p->prefix);
                        goto fail;
                }

                if (!nm_is_identifier(scan, vpname)) {
                        nmctx_ferror(ctx, "%s: invalid identifier '%.*s'", *pifname, vpname - scan, scan);
                        goto fail;
                }
        } else {
                if ((p->flags & NR_P_ID) && !(p->flags & NR_P_EMPTYID)) {
                        nmctx_ferror(ctx, "%s: identifier is missing between '%s' and ':'", *pifname, p->prefix);
                        goto fail;
                }
        }
        ++vpname; /* skip the colon */
        if (p->flags & NR_P_SKIP)
                ifname = vpname;
        scan = vpname;

        /* scan for a separator */
        for (; *scan && !index("-*^/@", *scan); scan++)
                ;

        /* search for possible pipe indicators */
        for (pipesep = vpname; pipesep != scan && !index("{}", *pipesep); pipesep++)
                ;

        if (pipesep != scan) {
                pipesep++;
                if (*pipesep == '\0') {
                        nmctx_ferror(ctx, "%s: invalid empty pipe name", *pifname);
                        goto fail;
                }
                if (!nm_is_identifier(pipesep, scan)) {
                        nmctx_ferror(ctx, "%s: invalid pipe name '%.*s'", *pifname, scan - pipesep, pipesep);
                        goto fail;
                }
        }

        namelen = scan - ifname;
        if (namelen >= sizeof(h->nr_name)) {
                nmctx_ferror(ctx, "name '%.*s' too long", namelen, ifname);
                goto fail;
        }
        if (namelen == 0) {
                nmctx_ferror(ctx, "%s: invalid empty port name", *pifname);
                goto fail;
        }

        /* fill the header */
        memcpy(h->nr_name, ifname, namelen);
        h->nr_name[namelen] = '\0';
        ED("name %s", h->nr_name);

        *pifname = scan;

        return 0;
fail:
        errno = EINVAL;
        return -1;
}


/*
 * 0 not recognized
 * -1 error
 *  >= 0 mem_id
 */
int32_t
nmreq_get_mem_id(const char **pifname, struct nmctx *ctx)
{
        int fd = -1;
        struct nmreq_header gh;
        struct nmreq_port_info_get gb;
        const char *ifname;

        errno = 0;
        ifname = *pifname;

        if (ifname == NULL)
                goto fail;

        /* try to look for a netmap port with this name */
        fd = open("/dev/netmap", O_RDWR);
        if (fd < 0) {
                nmctx_ferror(ctx, "cannot open /dev/netmap: %s", strerror(errno));
                goto fail;
        }
        nmreq_header_init(&gh, NETMAP_REQ_PORT_INFO_GET, &gb);
        if (nmreq_header_decode(&ifname, &gh, ctx) < 0) {
                goto fail;
        }
        memset(&gb, 0, sizeof(gb));
        if (ioctl(fd, NIOCCTRL, &gh) < 0) {
                nmctx_ferror(ctx, "cannot get info for '%s': %s", *pifname, strerror(errno));
                goto fail;
        }
        *pifname = ifname;
        close(fd);
        return gb.nr_mem_id;

fail:
        if (fd >= 0)
                close(fd);
        if (!errno)
                errno = EINVAL;
        return -1;
}


int
nmreq_register_decode(const char **pifname, struct nmreq_register *r, struct nmctx *ctx)
{
        enum { P_START, P_RNGSFXOK, P_GETNUM, P_FLAGS, P_FLAGSOK, P_MEMID, P_ONESW } p_state;
        long num;
        const char *scan = *pifname;
        uint32_t nr_mode;
        uint16_t nr_mem_id;
        uint16_t nr_ringid;
        uint64_t nr_flags;

        errno = 0;

        /* fill the request */

        p_state = P_START;
        /* defaults */
        nr_mode = NR_REG_ALL_NIC; /* default for no suffix */
        nr_mem_id = r->nr_mem_id; /* if non-zero, further updates are disabled */
        nr_ringid = 0;
        nr_flags = 0;
        while (*scan) {
                switch (p_state) {
                case P_START:
                        switch (*scan) {
                        case '^': /* only SW ring */
                                nr_mode = NR_REG_SW;
                                p_state = P_ONESW;
                                break;
                        case '*': /* NIC and SW */
                                nr_mode = NR_REG_NIC_SW;
                                p_state = P_RNGSFXOK;
                                break;
                        case '-': /* one NIC ring pair */
                                nr_mode = NR_REG_ONE_NIC;
                                p_state = P_GETNUM;
                                break;
                        case '/': /* start of flags */
                                p_state = P_FLAGS;
                                break;
                        case '@': /* start of memid */
                                p_state = P_MEMID;
                                break;
                        default:
                                nmctx_ferror(ctx, "unknown modifier: '%c'", *scan);
                                goto fail;
                        }
                        scan++;
                        break;
                case P_RNGSFXOK:
                        switch (*scan) {
                        case '/':
                                p_state = P_FLAGS;
                                break;
                        case '@':
                                p_state = P_MEMID;
                                break;
                        default:
                                nmctx_ferror(ctx, "unexpected character: '%c'", *scan);
                                goto fail;
                        }
                        scan++;
                        break;
                case P_GETNUM:
                        if (!isdigit(*scan)) {
                                nmctx_ferror(ctx, "got '%s' while expecting a number", scan);
                                goto fail;
                        }
                        num = strtol(scan, (char **)&scan, 10);
                        if (num < 0 || num >= NETMAP_RING_MASK) {
                                nmctx_ferror(ctx, "'%ld' out of range [0, %d)",
                                                num, NETMAP_RING_MASK);
                                goto fail;
                        }
                        nr_ringid = num & NETMAP_RING_MASK;
                        p_state = P_RNGSFXOK;
                        break;
                case P_FLAGS:
                case P_FLAGSOK:
                        switch (*scan) {
                        case '@':
                                p_state = P_MEMID;
                                scan++;
                                continue;
                        case 'x':
                                nr_flags |= NR_EXCLUSIVE;
                                break;
                        case 'z':
                                nr_flags |= NR_ZCOPY_MON;
                                break;
                        case 't':
                                nr_flags |= NR_MONITOR_TX;
                                break;
                        case 'r':
                                nr_flags |= NR_MONITOR_RX;
                                break;
                        case 'R':
                                nr_flags |= NR_RX_RINGS_ONLY;
                                break;
                        case 'T':
                                nr_flags |= NR_TX_RINGS_ONLY;
                                break;
                        default:
                                nmctx_ferror(ctx, "unrecognized flag: '%c'", *scan);
                                goto fail;
                        }
                        scan++;
                        p_state = P_FLAGSOK;
                        break;
                case P_MEMID:
                        if (!isdigit(*scan)) {
                                scan--; /* escape to options */
                                goto out;
                        }
                        num = strtol(scan, (char **)&scan, 10);
                        if (num <= 0) {
                                nmctx_ferror(ctx, "invalid mem_id: '%ld'", num);
                                goto fail;
                        }
                        if (nr_mem_id && nr_mem_id != num) {
                                nmctx_ferror(ctx, "invalid setting of mem_id to %ld (already set to %"PRIu16")", num, nr_mem_id);
                                goto fail;
                        }
                        nr_mem_id = num;
                        p_state = P_RNGSFXOK;
                        break;
                case P_ONESW:
                        if (!isdigit(*scan)) {
                                p_state = P_RNGSFXOK;
                        } else {
                                nr_mode = NR_REG_ONE_SW;
                                p_state = P_GETNUM;
                        }
                        break;
                }
        }
        if (p_state == P_MEMID && !*scan) {
                nmctx_ferror(ctx, "invalid empty mem_id");
                goto fail;
        }
        if (p_state != P_START && p_state != P_RNGSFXOK &&
            p_state != P_FLAGSOK && p_state != P_MEMID && p_state != P_ONESW) {
                nmctx_ferror(ctx, "unexpected end of request");
                goto fail;
        }
out:
        ED("flags: %s %s %s %s %s %s",
                        (nr_flags & NR_EXCLUSIVE) ? "EXCLUSIVE" : "",
                        (nr_flags & NR_ZCOPY_MON) ? "ZCOPY_MON" : "",
                        (nr_flags & NR_MONITOR_TX) ? "MONITOR_TX" : "",
                        (nr_flags & NR_MONITOR_RX) ? "MONITOR_RX" : "",
                        (nr_flags & NR_RX_RINGS_ONLY) ? "RX_RINGS_ONLY" : "",
                        (nr_flags & NR_TX_RINGS_ONLY) ? "TX_RINGS_ONLY" : "");
        r->nr_mode = nr_mode;
        r->nr_ringid = nr_ringid;
        r->nr_flags = nr_flags;
        r->nr_mem_id = nr_mem_id;
        *pifname = scan;
        return 0;

fail:
        if (!errno)
                errno = EINVAL;
        return -1;
}


static int
nmreq_option_parsekeys(const char *prefix, char *body, struct nmreq_opt_parser *p,
                struct nmreq_parse_ctx *pctx)
{
        char *scan;
        char delim1;
        struct nmreq_opt_key *k;

        scan = body;
        delim1 = *scan;
        while (delim1 != '\0') {
                char *key, *value;
                char delim;
                size_t vlen;

                key = scan;
                for ( scan++; *scan != '\0' && *scan != '=' && *scan != ','; scan++) {
                        if (*scan == '-')
                                *scan = '_';
                }
                delim = *scan;
                *scan = '\0';
                scan++;
                for (k = p->keys; (k - p->keys) < NMREQ_OPT_MAXKEYS && k->key != NULL;
                                k++) {
                        if (!strcmp(k->key, key))
                                goto found;

                }
                nmctx_ferror(pctx->ctx, "unknown key: '%s'", key);
                errno = EINVAL;
                return -1;
        found:
                if (pctx->keys[k->id] != NULL) {
                        nmctx_ferror(pctx->ctx, "option '%s': duplicate key '%s', already set to '%s'",
                                        prefix, key, pctx->keys[k->id]);
                        errno = EINVAL;
                        return -1;
                }
                value = scan;
                for ( ; *scan != '\0' && *scan != ','; scan++)
                        ;
                delim1 = *scan;
                *scan = '\0';
                vlen = scan - value;
                scan++;
                if (delim == '=') {
                        pctx->keys[k->id] = (vlen ? value : NULL);
                } else {
                        if (!(k->flags & NMREQ_OPTK_ALLOWEMPTY)) {
                                nmctx_ferror(pctx->ctx, "option '%s': missing '=value' for key '%s'",
                                                prefix, key);
                                errno = EINVAL;
                                return -1;
                        }
                        pctx->keys[k->id] = key;
                }
        }
        /* now check that all no-default keys have been assigned */
        for (k = p->keys; (k - p->keys) < NMREQ_OPT_MAXKEYS && k->key != NULL; k++) {
                if ((k->flags & NMREQ_OPTK_MUSTSET) && pctx->keys[k->id] == NULL) {
                        nmctx_ferror(pctx->ctx, "option '%s': mandatory key '%s' not assigned",
                                        prefix, k->key);
                        errno = EINVAL;
                        return -1;
                }
        }
        return 0;
}


static int
nmreq_option_decode1(char *opt, struct nmreq_opt_parser *parsers,
                void *token, struct nmctx *ctx)
{
        struct nmreq_opt_parser *p;
        const char *prefix;
        char *scan;
        char delim;
        struct nmreq_parse_ctx pctx;
        int i;

        prefix = opt;
        /* find the delimiter */
        for (scan = opt; *scan != '\0' && *scan != ':' && *scan != '='; scan++)
                ;
        delim = *scan;
        *scan = '\0';
        scan++;
        /* find the prefix */
        for (p = parsers; p != NULL; p = p->next) {
                if (!strcmp(prefix, p->prefix))
                        break;
        }
        if (p == NULL) {
                nmctx_ferror(ctx, "unknown option: '%s'", prefix);
                errno = EINVAL;
                return -1;
        }
        if (p->flags & NMREQ_OPTF_DISABLED) {
                nmctx_ferror(ctx, "option '%s' is not supported", prefix);
                errno = EOPNOTSUPP;
                return -1;
        }
        /* prepare the parse context */
        pctx.ctx = ctx;
        pctx.token = token;
        for (i = 0; i < NMREQ_OPT_MAXKEYS; i++)
                pctx.keys[i] = NULL;
        switch (delim) {
        case '\0':
                /* no body */
                if (!(p->flags & NMREQ_OPTF_ALLOWEMPTY)) {
                        nmctx_ferror(ctx, "syntax error: missing body after '%s'",
                                        prefix);
                        errno = EINVAL;
                        return -1;
                }
                break;
        case '=': /* the body goes to the default option key, if any */
                if (p->default_key < 0 || p->default_key >= NMREQ_OPT_MAXKEYS) {
                        nmctx_ferror(ctx, "syntax error: '=' not valid after '%s'",
                                        prefix);
                        errno = EINVAL;
                        return -1;
                }
                if (*scan == '\0') {
                        nmctx_ferror(ctx, "missing value for option '%s'", prefix);
                        errno = EINVAL;
                        return -1;
                }
                pctx.keys[p->default_key] = scan;
                break;
        case ':': /* parse 'key=value' strings */
                if (nmreq_option_parsekeys(prefix, scan, p, &pctx) < 0)
                        return -1;
                break;
        }
        return p->parse(&pctx);
}

int
nmreq_options_decode(const char *opt, struct nmreq_opt_parser parsers[],
                void *token, struct nmctx *ctx)
{
        const char *scan, *opt1;
        char *w;
        size_t len;
        int ret;

        if (*opt == '\0')
                return 0; /* empty list, OK */

        if (*opt != '@') {
                nmctx_ferror(ctx, "option list does not start with '@'");
                errno = EINVAL;
                return -1;
        }

        scan = opt;
        do {
                scan++; /* skip the plus */
                opt1 = scan; /* start of option */
                /* find the end of the option */
                for ( ; *scan != '\0' && *scan != '@'; scan++)
                        ;
                len = scan - opt1;
                if (len == 0) {
                        nmctx_ferror(ctx, "invalid empty option");
                        errno = EINVAL;
                        return -1;
                }
                w = nmctx_malloc(ctx, len + 1);
                if (w == NULL) {
                        nmctx_ferror(ctx, "out of memory");
                        errno = ENOMEM;
                        return -1;
                }
                memcpy(w, opt1, len);
                w[len] = '\0';
                ret = nmreq_option_decode1(w, parsers, token, ctx);
                nmctx_free(ctx, w);
                if (ret < 0)
                        return -1;
        } while (*scan != '\0');

        return 0;
}

struct nmreq_option *
nmreq_find_option(struct nmreq_header *h, uint32_t t)
{
        struct nmreq_option *o = NULL;

        nmreq_foreach_option(h, o) {
                if (o->nro_reqtype == t)
                        break;
        }
        return o;
}

void
nmreq_remove_option(struct nmreq_header *h, struct nmreq_option *o)
{
        struct nmreq_option **nmo;

        for (nmo = (struct nmreq_option **)&h->nr_options; *nmo != NULL;
            nmo = (struct nmreq_option **)&(*nmo)->nro_next) {
                if (*nmo == o) {
                        *((uint64_t *)(*nmo)) = o->nro_next;
                        o->nro_next = (uint64_t)(uintptr_t)NULL;
                        break;
                }
        }
}

void
nmreq_free_options(struct nmreq_header *h)
{
        struct nmreq_option *o, *next;

        /*
         * Note: can't use nmreq_foreach_option() here; it frees the
         * list as it's walking and nmreq_foreach_option() isn't
         * modification-safe.
         */
        for (o = (struct nmreq_option *)(uintptr_t)h->nr_options; o != NULL;
            o = next) {
                next = (struct nmreq_option *)(uintptr_t)o->nro_next;
                free(o);
        }
}

const char*
nmreq_option_name(uint32_t nro_reqtype)
{
        switch (nro_reqtype) {
        case NETMAP_REQ_OPT_EXTMEM:
                return "extmem";
        case NETMAP_REQ_OPT_SYNC_KLOOP_EVENTFDS:
                return "sync-kloop-eventfds";
        case NETMAP_REQ_OPT_CSB:
                return "csb";
        case NETMAP_REQ_OPT_SYNC_KLOOP_MODE:
                return "sync-kloop-mode";
        case NETMAP_REQ_OPT_OFFSETS:
                return "offsets";
        default:
                return "unknown";
        }
}

#if 0
#include <inttypes.h>
static void
nmreq_dump(struct nmport_d *d)
{
        printf("header:\n");
        printf("   nr_version:  %"PRIu16"\n", d->hdr.nr_version);
        printf("   nr_reqtype:  %"PRIu16"\n", d->hdr.nr_reqtype);
        printf("   nr_reserved: %"PRIu32"\n", d->hdr.nr_reserved);
        printf("   nr_name:     %s\n", d->hdr.nr_name);
        printf("   nr_options:  %lx\n", (unsigned long)d->hdr.nr_options);
        printf("   nr_body:     %lx\n", (unsigned long)d->hdr.nr_body);
        printf("\n");
        printf("register (%p):\n", (void *)d->hdr.nr_body);
        printf("   nr_mem_id:   %"PRIu16"\n", d->reg.nr_mem_id);
        printf("   nr_ringid:   %"PRIu16"\n", d->reg.nr_ringid);
        printf("   nr_mode:     %lx\n", (unsigned long)d->reg.nr_mode);
        printf("   nr_flags:    %lx\n", (unsigned long)d->reg.nr_flags);
        printf("\n");
        if (d->hdr.nr_options) {
                struct nmreq_opt_extmem *e = (struct nmreq_opt_extmem *)d->hdr.nr_options;
                printf("opt_extmem (%p):\n", e);
                printf("   nro_opt.nro_next:    %lx\n", (unsigned long)e->nro_opt.nro_next);
                printf("   nro_opt.nro_reqtype: %"PRIu32"\n", e->nro_opt.nro_reqtype);
                printf("   nro_usrptr:          %lx\n", (unsigned long)e->nro_usrptr);
                printf("   nro_info.nr_memsize  %"PRIu64"\n", e->nro_info.nr_memsize);
        }
        printf("\n");
        printf("mem (%p):\n", d->mem);
        printf("   refcount:   %d\n", d->mem->refcount);
        printf("   mem:        %p\n", d->mem->mem);
        printf("   size:       %zu\n", d->mem->size);
        printf("\n");
        printf("rings:\n");
        printf("   tx:   [%d, %d]\n", d->first_tx_ring, d->last_tx_ring);
        printf("   rx:   [%d, %d]\n", d->first_rx_ring, d->last_rx_ring);
}
int
main(int argc, char *argv[])
{
        struct nmport_d *d;

        if (argc < 2) {
                fprintf(stderr, "usage: %s netmap-expr\n", argv[0]);
                return 1;
        }

        d = nmport_open(argv[1]);
        if (d != NULL) {
                nmreq_dump(d);
                nmport_close(d);
        }

        return 0;
}
#endif