/* SPDX-License-Identifier: GPL-2.0
 * Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc.
 */
static const char *__doc__=
 "XDP monitor tool, based on tracepoints\n"
;

static const char *__doc_err_only__=
 " NOTICE: Only tracking XDP redirect errors\n"
 "         Enable TX success stats via '--stats'\n"
 "         (which comes with a per packet processing overhead)\n"
;

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <locale.h>

#include <sys/resource.h>
#include <getopt.h>
#include <net/if.h>
#include <time.h>

#include "libbpf.h"
#include "bpf_load.h"
#include "bpf_util.h"

static int verbose = 1;
static bool debug = false;

static const struct option long_options[] = {
        {"help",        no_argument,            NULL, 'h' },
        {"debug",       no_argument,            NULL, 'D' },
        {"stats",       no_argument,            NULL, 'S' },
        {"sec",         required_argument,      NULL, 's' },
        {0, 0, NULL,  0 }
};

/* C standard specifies two constants, EXIT_SUCCESS(0) and EXIT_FAILURE(1) */
#define EXIT_FAIL_MEM   5

static void usage(char *argv[])
{
        int i;
        printf("\nDOCUMENTATION:\n%s\n", __doc__);
        printf("\n");
        printf(" Usage: %s (options-see-below)\n",
               argv[0]);
        printf(" Listing options:\n");
        for (i = 0; long_options[i].name != 0; i++) {
                printf(" --%-15s", long_options[i].name);
                if (long_options[i].flag != NULL)
                        printf(" flag (internal value:%d)",
                               *long_options[i].flag);
                else
                        printf("(internal short-option: -%c)",
                               long_options[i].val);
                printf("\n");
        }
        printf("\n");
}

#define NANOSEC_PER_SEC 1000000000 /* 10^9 */
static __u64 gettime(void)
{
        struct timespec t;
        int res;

        res = clock_gettime(CLOCK_MONOTONIC, &t);
        if (res < 0) {
                fprintf(stderr, "Error with gettimeofday! (%i)\n", res);
                exit(EXIT_FAILURE);
        }
        return (__u64) t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec;
}

enum {
        REDIR_SUCCESS = 0,
        REDIR_ERROR = 1,
};
#define REDIR_RES_MAX 2
static const char *redir_names[REDIR_RES_MAX] = {
        [REDIR_SUCCESS] = "Success",
        [REDIR_ERROR]   = "Error",
};
static const char *err2str(int err)
{
        if (err < REDIR_RES_MAX)
                return redir_names[err];
        return NULL;
}
/* enum xdp_action */
#define XDP_UNKNOWN     XDP_REDIRECT + 1
#define XDP_ACTION_MAX (XDP_UNKNOWN + 1)
static const char *xdp_action_names[XDP_ACTION_MAX] = {
        [XDP_ABORTED]   = "XDP_ABORTED",
        [XDP_DROP]      = "XDP_DROP",
        [XDP_PASS]      = "XDP_PASS",
        [XDP_TX]        = "XDP_TX",
        [XDP_REDIRECT]  = "XDP_REDIRECT",
        [XDP_UNKNOWN]   = "XDP_UNKNOWN",
};
static const char *action2str(int action)
{
        if (action < XDP_ACTION_MAX)
                return xdp_action_names[action];
        return NULL;
}

/* Common stats data record shared with _kern.c */
struct datarec {
        __u64 processed;
        __u64 dropped;
        __u64 info;
};
#define MAX_CPUS 64

/* Userspace structs for collection of stats from maps */
struct record {
        __u64 timestamp;
        struct datarec total;
        struct datarec *cpu;
};
struct u64rec {
        __u64 processed;
};
struct record_u64 {
        /* record for _kern side __u64 values */
        __u64 timestamp;
        struct u64rec total;
        struct u64rec *cpu;
};

struct stats_record {
        struct record_u64 xdp_redirect[REDIR_RES_MAX];
        struct record_u64 xdp_exception[XDP_ACTION_MAX];
        struct record xdp_cpumap_kthread;
        struct record xdp_cpumap_enqueue[MAX_CPUS];
};

static bool map_collect_record(int fd, __u32 key, struct record *rec)
{
        /* For percpu maps, userspace gets a value per possible CPU */
        unsigned int nr_cpus = bpf_num_possible_cpus();
        struct datarec values[nr_cpus];
        __u64 sum_processed = 0;
        __u64 sum_dropped = 0;
        __u64 sum_info = 0;
        int i;

        if ((bpf_map_lookup_elem(fd, &key, values)) != 0) {
                fprintf(stderr,
                        "ERR: bpf_map_lookup_elem failed key:0x%X\n", key);
                return false;
        }
        /* Get time as close as possible to reading map contents */
        rec->timestamp = gettime();

        /* Record and sum values from each CPU */
        for (i = 0; i < nr_cpus; i++) {
                rec->cpu[i].processed = values[i].processed;
                sum_processed        += values[i].processed;
                rec->cpu[i].dropped = values[i].dropped;
                sum_dropped        += values[i].dropped;
                rec->cpu[i].info = values[i].info;
                sum_info        += values[i].info;
        }
        rec->total.processed = sum_processed;
        rec->total.dropped   = sum_dropped;
        rec->total.info      = sum_info;
        return true;
}

static bool map_collect_record_u64(int fd, __u32 key, struct record_u64 *rec)
{
        /* For percpu maps, userspace gets a value per possible CPU */
        unsigned int nr_cpus = bpf_num_possible_cpus();
        struct u64rec values[nr_cpus];
        __u64 sum_total = 0;
        int i;

        if ((bpf_map_lookup_elem(fd, &key, values)) != 0) {
                fprintf(stderr,
                        "ERR: bpf_map_lookup_elem failed key:0x%X\n", key);
                return false;
        }
        /* Get time as close as possible to reading map contents */
        rec->timestamp = gettime();

        /* Record and sum values from each CPU */
        for (i = 0; i < nr_cpus; i++) {
                rec->cpu[i].processed = values[i].processed;
                sum_total            += values[i].processed;
        }
        rec->total.processed = sum_total;
        return true;
}

static double calc_period(struct record *r, struct record *p)
{
        double period_ = 0;
        __u64 period = 0;

        period = r->timestamp - p->timestamp;
        if (period > 0)
                period_ = ((double) period / NANOSEC_PER_SEC);

        return period_;
}

static double calc_period_u64(struct record_u64 *r, struct record_u64 *p)
{
        double period_ = 0;
        __u64 period = 0;

        period = r->timestamp - p->timestamp;
        if (period > 0)
                period_ = ((double) period / NANOSEC_PER_SEC);

        return period_;
}

static double calc_pps(struct datarec *r, struct datarec *p, double period)
{
        __u64 packets = 0;
        double pps = 0;

        if (period > 0) {
                packets = r->processed - p->processed;
                pps = packets / period;
        }
        return pps;
}

static double calc_pps_u64(struct u64rec *r, struct u64rec *p, double period)
{
        __u64 packets = 0;
        double pps = 0;

        if (period > 0) {
                packets = r->processed - p->processed;
                pps = packets / period;
        }
        return pps;
}

static double calc_drop(struct datarec *r, struct datarec *p, double period)
{
        __u64 packets = 0;
        double pps = 0;

        if (period > 0) {
                packets = r->dropped - p->dropped;
                pps = packets / period;
        }
        return pps;
}

static double calc_info(struct datarec *r, struct datarec *p, double period)
{
        __u64 packets = 0;
        double pps = 0;

        if (period > 0) {
                packets = r->info - p->info;
                pps = packets / period;
        }
        return pps;
}

static void stats_print(struct stats_record *stats_rec,
                        struct stats_record *stats_prev,
                        bool err_only)
{
        unsigned int nr_cpus = bpf_num_possible_cpus();
        int rec_i = 0, i, to_cpu;
        double t = 0, pps = 0;

        /* Header */
        printf("%-15s %-7s %-12s %-12s %-9s\n",
               "XDP-event", "CPU:to", "pps", "drop-pps", "extra-info");

        /* tracepoint: xdp:xdp_redirect_* */
        if (err_only)
                rec_i = REDIR_ERROR;

        for (; rec_i < REDIR_RES_MAX; rec_i++) {
                struct record_u64 *rec, *prev;
                char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %s\n";
                char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %s\n";

                rec  =  &stats_rec->xdp_redirect[rec_i];
                prev = &stats_prev->xdp_redirect[rec_i];
                t = calc_period_u64(rec, prev);

                for (i = 0; i < nr_cpus; i++) {
                        struct u64rec *r = &rec->cpu[i];
                        struct u64rec *p = &prev->cpu[i];

                        pps = calc_pps_u64(r, p, t);
                        if (pps > 0)
                                printf(fmt1, "XDP_REDIRECT", i,
                                       rec_i ? 0.0: pps, rec_i ? pps : 0.0,
                                       err2str(rec_i));
                }
                pps = calc_pps_u64(&rec->total, &prev->total, t);
                printf(fmt2, "XDP_REDIRECT", "total",
                       rec_i ? 0.0: pps, rec_i ? pps : 0.0, err2str(rec_i));
        }

        /* tracepoint: xdp:xdp_exception */
        for (rec_i = 0; rec_i < XDP_ACTION_MAX; rec_i++) {
                struct record_u64 *rec, *prev;
                char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %s\n";
                char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %s\n";

                rec  =  &stats_rec->xdp_exception[rec_i];
                prev = &stats_prev->xdp_exception[rec_i];
                t = calc_period_u64(rec, prev);

                for (i = 0; i < nr_cpus; i++) {
                        struct u64rec *r = &rec->cpu[i];
                        struct u64rec *p = &prev->cpu[i];

                        pps = calc_pps_u64(r, p, t);
                        if (pps > 0)
                                printf(fmt1, "Exception", i,
                                       0.0, pps, err2str(rec_i));
                }
                pps = calc_pps_u64(&rec->total, &prev->total, t);
                if (pps > 0)
                        printf(fmt2, "Exception", "total",
                               0.0, pps, action2str(rec_i));
        }

        /* cpumap enqueue stats */
        for (to_cpu = 0; to_cpu < MAX_CPUS; to_cpu++) {
                char *fmt1 = "%-15s %3d:%-3d %'-12.0f %'-12.0f %'-10.2f %s\n";
                char *fmt2 = "%-15s %3s:%-3d %'-12.0f %'-12.0f %'-10.2f %s\n";
                struct record *rec, *prev;
                char *info_str = "";
                double drop, info;

                rec  =  &stats_rec->xdp_cpumap_enqueue[to_cpu];
                prev = &stats_prev->xdp_cpumap_enqueue[to_cpu];
                t = calc_period(rec, prev);
                for (i = 0; i < nr_cpus; i++) {
                        struct datarec *r = &rec->cpu[i];
                        struct datarec *p = &prev->cpu[i];

                        pps  = calc_pps(r, p, t);
                        drop = calc_drop(r, p, t);
                        info = calc_info(r, p, t);
                        if (info > 0) {
                                info_str = "bulk-average";
                                info = pps / info; /* calc average bulk size */
                        }
                        if (pps > 0)
                                printf(fmt1, "cpumap-enqueue",
                                       i, to_cpu, pps, drop, info, info_str);
                }
                pps = calc_pps(&rec->total, &prev->total, t);
                if (pps > 0) {
                        drop = calc_drop(&rec->total, &prev->total, t);
                        info = calc_info(&rec->total, &prev->total, t);
                        if (info > 0) {
                                info_str = "bulk-average";
                                info = pps / info; /* calc average bulk size */
                        }
                        printf(fmt2, "cpumap-enqueue",
                               "sum", to_cpu, pps, drop, info, info_str);
                }
        }

        /* cpumap kthread stats */
        {
                char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %'-10.0f %s\n";
                char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %'-10.0f %s\n";
                struct record *rec, *prev;
                double drop, info;
                char *i_str = "";

                rec  =  &stats_rec->xdp_cpumap_kthread;
                prev = &stats_prev->xdp_cpumap_kthread;
                t = calc_period(rec, prev);
                for (i = 0; i < nr_cpus; i++) {
                        struct datarec *r = &rec->cpu[i];
                        struct datarec *p = &prev->cpu[i];

                        pps  = calc_pps(r, p, t);
                        drop = calc_drop(r, p, t);
                        info = calc_info(r, p, t);
                        if (info > 0)
                                i_str = "sched";
                        if (pps > 0)
                                printf(fmt1, "cpumap-kthread",
                                       i, pps, drop, info, i_str);
                }
                pps = calc_pps(&rec->total, &prev->total, t);
                drop = calc_drop(&rec->total, &prev->total, t);
                info = calc_info(&rec->total, &prev->total, t);
                if (info > 0)
                        i_str = "sched-sum";
                printf(fmt2, "cpumap-kthread", "total", pps, drop, info, i_str);
        }

        printf("\n");
}

static bool stats_collect(struct stats_record *rec)
{
        int fd;
        int i;

        /* TODO: Detect if someone unloaded the perf event_fd's, as
         * this can happen by someone running perf-record -e
         */

        fd = map_data[0].fd; /* map0: redirect_err_cnt */
        for (i = 0; i < REDIR_RES_MAX; i++)
                map_collect_record_u64(fd, i, &rec->xdp_redirect[i]);

        fd = map_data[1].fd; /* map1: exception_cnt */
        for (i = 0; i < XDP_ACTION_MAX; i++) {
                map_collect_record_u64(fd, i, &rec->xdp_exception[i]);
        }

        fd = map_data[2].fd; /* map2: cpumap_enqueue_cnt */
        for (i = 0; i < MAX_CPUS; i++)
                map_collect_record(fd, i, &rec->xdp_cpumap_enqueue[i]);

        fd = map_data[3].fd; /* map3: cpumap_kthread_cnt */
        map_collect_record(fd, 0, &rec->xdp_cpumap_kthread);

        return true;
}

static void *alloc_rec_per_cpu(int record_size)
{
        unsigned int nr_cpus = bpf_num_possible_cpus();
        void *array;
        size_t size;

        size = record_size * nr_cpus;
        array = malloc(size);
        memset(array, 0, size);
        if (!array) {
                fprintf(stderr, "Mem alloc error (nr_cpus:%u)\n", nr_cpus);
                exit(EXIT_FAIL_MEM);
        }
        return array;
}

static struct stats_record *alloc_stats_record(void)
{
        struct stats_record *rec;
        int rec_sz;
        int i;

        /* Alloc main stats_record structure */
        rec = malloc(sizeof(*rec));
        memset(rec, 0, sizeof(*rec));
        if (!rec) {
                fprintf(stderr, "Mem alloc error\n");
                exit(EXIT_FAIL_MEM);
        }

        /* Alloc stats stored per CPU for each record */
        rec_sz = sizeof(struct u64rec);
        for (i = 0; i < REDIR_RES_MAX; i++)
                rec->xdp_redirect[i].cpu = alloc_rec_per_cpu(rec_sz);

        for (i = 0; i < XDP_ACTION_MAX; i++)
                rec->xdp_exception[i].cpu = alloc_rec_per_cpu(rec_sz);

        rec_sz = sizeof(struct datarec);
        rec->xdp_cpumap_kthread.cpu = alloc_rec_per_cpu(rec_sz);

        for (i = 0; i < MAX_CPUS; i++)
                rec->xdp_cpumap_enqueue[i].cpu = alloc_rec_per_cpu(rec_sz);

        return rec;
}

static void free_stats_record(struct stats_record *r)
{
        int i;

        for (i = 0; i < REDIR_RES_MAX; i++)
                free(r->xdp_redirect[i].cpu);

        for (i = 0; i < XDP_ACTION_MAX; i++)
                free(r->xdp_exception[i].cpu);

        free(r->xdp_cpumap_kthread.cpu);

        for (i = 0; i < MAX_CPUS; i++)
                free(r->xdp_cpumap_enqueue[i].cpu);

        free(r);
}

/* Pointer swap trick */
static inline void swap(struct stats_record **a, struct stats_record **b)
{
        struct stats_record *tmp;

        tmp = *a;
        *a = *b;
        *b = tmp;
}

static void stats_poll(int interval, bool err_only)
{
        struct stats_record *rec, *prev;

        rec  = alloc_stats_record();
        prev = alloc_stats_record();
        stats_collect(rec);

        if (err_only)
                printf("\n%s\n", __doc_err_only__);

        /* Trick to pretty printf with thousands separators use %' */
        setlocale(LC_NUMERIC, "en_US");

        /* Header */
        if (verbose)
                printf("\n%s", __doc__);

        /* TODO Need more advanced stats on error types */
        if (verbose) {
                printf(" - Stats map0: %s\n", map_data[0].name);
                printf(" - Stats map1: %s\n", map_data[1].name);
                printf("\n");
        }
        fflush(stdout);

        while (1) {
                swap(&prev, &rec);
                stats_collect(rec);
                stats_print(rec, prev, err_only);
                fflush(stdout);
                sleep(interval);
        }

        free_stats_record(rec);
        free_stats_record(prev);
}

static void print_bpf_prog_info(void)
{
        int i;

        /* Prog info */
        printf("Loaded BPF prog have %d bpf program(s)\n", prog_cnt);
        for (i = 0; i < prog_cnt; i++) {
                printf(" - prog_fd[%d] = fd(%d)\n", i, prog_fd[i]);
        }

        /* Maps info */
        printf("Loaded BPF prog have %d map(s)\n", map_data_count);
        for (i = 0; i < map_data_count; i++) {
                char *name = map_data[i].name;
                int fd     = map_data[i].fd;

                printf(" - map_data[%d] = fd(%d) name:%s\n", i, fd, name);
        }

        /* Event info */
        printf("Searching for (max:%d) event file descriptor(s)\n", prog_cnt);
        for (i = 0; i < prog_cnt; i++) {
                if (event_fd[i] != -1)
                        printf(" - event_fd[%d] = fd(%d)\n", i, event_fd[i]);
        }
}

int main(int argc, char **argv)
{
        struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
        int longindex = 0, opt;
        int ret = EXIT_SUCCESS;
        char bpf_obj_file[256];

        /* Default settings: */
        bool errors_only = true;
        int interval = 2;

        snprintf(bpf_obj_file, sizeof(bpf_obj_file), "%s_kern.o", argv[0]);

        /* Parse commands line args */
        while ((opt = getopt_long(argc, argv, "h",
                                  long_options, &longindex)) != -1) {
                switch (opt) {
                case 'D':
                        debug = true;
                        break;
                case 'S':
                        errors_only = false;
                        break;
                case 's':
                        interval = atoi(optarg);
                        break;
                case 'h':
                default:
                        usage(argv);
                        return EXIT_FAILURE;
                }
        }

        if (setrlimit(RLIMIT_MEMLOCK, &r)) {
                perror("setrlimit(RLIMIT_MEMLOCK)");
                return EXIT_FAILURE;
        }

        if (load_bpf_file(bpf_obj_file)) {
                printf("ERROR - bpf_log_buf: %s", bpf_log_buf);
                return EXIT_FAILURE;
        }
        if (!prog_fd[0]) {
                printf("ERROR - load_bpf_file: %s\n", strerror(errno));
                return EXIT_FAILURE;
        }

        if (debug) {
                print_bpf_prog_info();
        }

        /* Unload/stop tracepoint event by closing fd's */
        if (errors_only) {
                /* The prog_fd[i] and event_fd[i] depend on the
                 * order the functions was defined in _kern.c
                 */
                close(event_fd[2]); /* tracepoint/xdp/xdp_redirect */
                close(prog_fd[2]);  /* func: trace_xdp_redirect */
                close(event_fd[3]); /* tracepoint/xdp/xdp_redirect_map */
                close(prog_fd[3]);  /* func: trace_xdp_redirect_map */
        }

        stats_poll(interval, errors_only);

        return ret;
}