/* GPLv2 Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc.
 */
static const char *__doc__ =
        " XDP redirect with a CPU-map type \"BPF_MAP_TYPE_CPUMAP\"";

#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <locale.h>
#include <sys/resource.h>
#include <getopt.h>
#include <net/if.h>
#include <time.h>

#include <arpa/inet.h>
#include <linux/if_link.h>

#define MAX_CPUS 64 /* WARNING - sync with _kern.c */

/* How many xdp_progs are defined in _kern.c */
#define MAX_PROG 6

/* Wanted to get rid of bpf_load.h and fake-"libbpf.h" (and instead
 * use bpf/libbpf.h), but cannot as (currently) needed for XDP
 * attaching to a device via bpf_set_link_xdp_fd()
 */
#include <bpf/bpf.h>
#include "bpf_load.h"

#include "bpf_util.h"

static int ifindex = -1;
static char ifname_buf[IF_NAMESIZE];
static char *ifname;

static __u32 xdp_flags;

/* Exit return codes */
#define EXIT_OK         0
#define EXIT_FAIL               1
#define EXIT_FAIL_OPTION        2
#define EXIT_FAIL_XDP           3
#define EXIT_FAIL_BPF           4
#define EXIT_FAIL_MEM           5

static const struct option long_options[] = {
        {"help",        no_argument,            NULL, 'h' },
        {"dev",         required_argument,      NULL, 'd' },
        {"skb-mode",    no_argument,            NULL, 'S' },
        {"debug",       no_argument,            NULL, 'D' },
        {"sec",         required_argument,      NULL, 's' },
        {"prognum",     required_argument,      NULL, 'p' },
        {"qsize",       required_argument,      NULL, 'q' },
        {"cpu",         required_argument,      NULL, 'c' },
        {"stress-mode", no_argument,            NULL, 'x' },
        {"no-separators", no_argument,          NULL, 'z' },
        {0, 0, NULL,  0 }
};

static void int_exit(int sig)
{
        fprintf(stderr,
                "Interrupted: Removing XDP program on ifindex:%d device:%s\n",
                ifindex, ifname);
        if (ifindex > -1)
                bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
        exit(EXIT_OK);
}

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(" --%-12s", long_options[i].name);
                if (long_options[i].flag != NULL)
                        printf(" flag (internal value:%d)",
                                *long_options[i].flag);
                else
                        printf(" short-option: -%c",
                                long_options[i].val);
                printf("\n");
        }
        printf("\n");
}

/* gettime returns the current time of day in nanoseconds.
 * Cost: clock_gettime (ns) => 26ns (CLOCK_MONOTONIC)
 *       clock_gettime (ns) =>  9ns (CLOCK_MONOTONIC_COARSE)
 */
#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_FAIL);
        }
        return (__u64) t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec;
}

/* Common stats data record shared with _kern.c */
struct datarec {
        __u64 processed;
        __u64 dropped;
        __u64 issue;
};
struct record {
        __u64 timestamp;
        struct datarec total;
        struct datarec *cpu;
};
struct stats_record {
        struct record rx_cnt;
        struct record redir_err;
        struct record kthread;
        struct record exception;
        struct record enq[MAX_CPUS];
};

static bool map_collect_percpu(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_issue = 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].issue = values[i].issue;
                sum_issue        += values[i].issue;
        }
        rec->total.processed = sum_processed;
        rec->total.dropped   = sum_dropped;
        rec->total.issue     = sum_issue;
        return true;
}

static struct datarec *alloc_record_per_cpu(void)
{
        unsigned int nr_cpus = bpf_num_possible_cpus();
        struct datarec *array;
        size_t size;

        size = sizeof(struct datarec) * 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 i;

        rec = malloc(sizeof(*rec));
        memset(rec, 0, sizeof(*rec));
        if (!rec) {
                fprintf(stderr, "Mem alloc error\n");
                exit(EXIT_FAIL_MEM);
        }
        rec->rx_cnt.cpu    = alloc_record_per_cpu();
        rec->redir_err.cpu = alloc_record_per_cpu();
        rec->kthread.cpu   = alloc_record_per_cpu();
        rec->exception.cpu = alloc_record_per_cpu();
        for (i = 0; i < MAX_CPUS; i++)
                rec->enq[i].cpu = alloc_record_per_cpu();

        return rec;
}

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

        for (i = 0; i < MAX_CPUS; i++)
                free(r->enq[i].cpu);
        free(r->exception.cpu);
        free(r->kthread.cpu);
        free(r->redir_err.cpu);
        free(r->rx_cnt.cpu);
        free(r);
}

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

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

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

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

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

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

static void stats_print(struct stats_record *stats_rec,
                        struct stats_record *stats_prev,
                        int prog_num)
{
        unsigned int nr_cpus = bpf_num_possible_cpus();
        double pps = 0, drop = 0, err = 0;
        struct record *rec, *prev;
        int to_cpu;
        double t;
        int i;

        /* Header */
        printf("Running XDP/eBPF prog_num:%d\n", prog_num);
        printf("%-15s %-7s %-14s %-11s %-9s\n",
               "XDP-cpumap", "CPU:to", "pps", "drop-pps", "extra-info");

        /* XDP rx_cnt */
        {
                char *fmt_rx = "%-15s %-7d %'-14.0f %'-11.0f %'-10.0f %s\n";
                char *fm2_rx = "%-15s %-7s %'-14.0f %'-11.0f\n";
                char *errstr = "";

                rec  = &stats_rec->rx_cnt;
                prev = &stats_prev->rx_cnt;
                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_pps(r, p, t);
                        err  = calc_errs_pps(r, p, t);
                        if (err > 0)
                                errstr = "cpu-dest/err";
                        if (pps > 0)
                                printf(fmt_rx, "XDP-RX",
                                        i, pps, drop, err, errstr);
                }
                pps  = calc_pps(&rec->total, &prev->total, t);
                drop = calc_drop_pps(&rec->total, &prev->total, t);
                err  = calc_errs_pps(&rec->total, &prev->total, t);
                printf(fm2_rx, "XDP-RX", "total", pps, drop);
        }

        /* cpumap enqueue stats */
        for (to_cpu = 0; to_cpu < MAX_CPUS; to_cpu++) {
                char *fmt = "%-15s %3d:%-3d %'-14.0f %'-11.0f %'-10.2f %s\n";
                char *fm2 = "%-15s %3s:%-3d %'-14.0f %'-11.0f %'-10.2f %s\n";
                char *errstr = "";

                rec  =  &stats_rec->enq[to_cpu];
                prev = &stats_prev->enq[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_pps(r, p, t);
                        err  = calc_errs_pps(r, p, t);
                        if (err > 0) {
                                errstr = "bulk-average";
                                err = pps / err; /* calc average bulk size */
                        }
                        if (pps > 0)
                                printf(fmt, "cpumap-enqueue",
                                       i, to_cpu, pps, drop, err, errstr);
                }
                pps = calc_pps(&rec->total, &prev->total, t);
                if (pps > 0) {
                        drop = calc_drop_pps(&rec->total, &prev->total, t);
                        err  = calc_errs_pps(&rec->total, &prev->total, t);
                        if (err > 0) {
                                errstr = "bulk-average";
                                err = pps / err; /* calc average bulk size */
                        }
                        printf(fm2, "cpumap-enqueue",
                               "sum", to_cpu, pps, drop, err, errstr);
                }
        }

        /* cpumap kthread stats */
        {
                char *fmt_k = "%-15s %-7d %'-14.0f %'-11.0f %'-10.0f %s\n";
                char *fm2_k = "%-15s %-7s %'-14.0f %'-11.0f %'-10.0f %s\n";
                char *e_str = "";

                rec  = &stats_rec->kthread;
                prev = &stats_prev->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_pps(r, p, t);
                        err  = calc_errs_pps(r, p, t);
                        if (err > 0)
                                e_str = "sched";
                        if (pps > 0)
                                printf(fmt_k, "cpumap_kthread",
                                       i, pps, drop, err, e_str);
                }
                pps = calc_pps(&rec->total, &prev->total, t);
                drop = calc_drop_pps(&rec->total, &prev->total, t);
                err  = calc_errs_pps(&rec->total, &prev->total, t);
                if (err > 0)
                        e_str = "sched-sum";
                printf(fm2_k, "cpumap_kthread", "total", pps, drop, err, e_str);
        }

        /* XDP redirect err tracepoints (very unlikely) */
        {
                char *fmt_err = "%-15s %-7d %'-14.0f %'-11.0f\n";
                char *fm2_err = "%-15s %-7s %'-14.0f %'-11.0f\n";

                rec  = &stats_rec->redir_err;
                prev = &stats_prev->redir_err;
                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_pps(r, p, t);
                        if (pps > 0)
                                printf(fmt_err, "redirect_err", i, pps, drop);
                }
                pps = calc_pps(&rec->total, &prev->total, t);
                drop = calc_drop_pps(&rec->total, &prev->total, t);
                printf(fm2_err, "redirect_err", "total", pps, drop);
        }

        /* XDP general exception tracepoints */
        {
                char *fmt_err = "%-15s %-7d %'-14.0f %'-11.0f\n";
                char *fm2_err = "%-15s %-7s %'-14.0f %'-11.0f\n";

                rec  = &stats_rec->exception;
                prev = &stats_prev->exception;
                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_pps(r, p, t);
                        if (pps > 0)
                                printf(fmt_err, "xdp_exception", i, pps, drop);
                }
                pps = calc_pps(&rec->total, &prev->total, t);
                drop = calc_drop_pps(&rec->total, &prev->total, t);
                printf(fm2_err, "xdp_exception", "total", pps, drop);
        }

        printf("\n");
        fflush(stdout);
}

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

        fd = map_fd[1]; /* map: rx_cnt */
        map_collect_percpu(fd, 0, &rec->rx_cnt);

        fd = map_fd[2]; /* map: redirect_err_cnt */
        map_collect_percpu(fd, 1, &rec->redir_err);

        fd = map_fd[3]; /* map: cpumap_enqueue_cnt */
        for (i = 0; i < MAX_CPUS; i++)
                map_collect_percpu(fd, i, &rec->enq[i]);

        fd = map_fd[4]; /* map: cpumap_kthread_cnt */
        map_collect_percpu(fd, 0, &rec->kthread);

        fd = map_fd[8]; /* map: exception_cnt */
        map_collect_percpu(fd, 0, &rec->exception);
}


/* 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 int create_cpu_entry(__u32 cpu, __u32 queue_size,
                            __u32 avail_idx, bool new)
{
        __u32 curr_cpus_count = 0;
        __u32 key = 0;
        int ret;

        /* Add a CPU entry to cpumap, as this allocate a cpu entry in
         * the kernel for the cpu.
         */
        ret = bpf_map_update_elem(map_fd[0], &cpu, &queue_size, 0);
        if (ret) {
                fprintf(stderr, "Create CPU entry failed (err:%d)\n", ret);
                exit(EXIT_FAIL_BPF);
        }

        /* Inform bpf_prog's that a new CPU is available to select
         * from via some control maps.
         */
        /* map_fd[5] = cpus_available */
        ret = bpf_map_update_elem(map_fd[5], &avail_idx, &cpu, 0);
        if (ret) {
                fprintf(stderr, "Add to avail CPUs failed\n");
                exit(EXIT_FAIL_BPF);
        }

        /* When not replacing/updating existing entry, bump the count */
        /* map_fd[6] = cpus_count */
        ret = bpf_map_lookup_elem(map_fd[6], &key, &curr_cpus_count);
        if (ret) {
                fprintf(stderr, "Failed reading curr cpus_count\n");
                exit(EXIT_FAIL_BPF);
        }
        if (new) {
                curr_cpus_count++;
                ret = bpf_map_update_elem(map_fd[6], &key, &curr_cpus_count, 0);
                if (ret) {
                        fprintf(stderr, "Failed write curr cpus_count\n");
                        exit(EXIT_FAIL_BPF);
                }
        }
        /* map_fd[7] = cpus_iterator */
        printf("%s CPU:%u as idx:%u queue_size:%d (total cpus_count:%u)\n",
               new ? "Add-new":"Replace", cpu, avail_idx,
               queue_size, curr_cpus_count);

        return 0;
}

/* CPUs are zero-indexed. Thus, add a special sentinel default value
 * in map cpus_available to mark CPU index'es not configured
 */
static void mark_cpus_unavailable(void)
{
        __u32 invalid_cpu = MAX_CPUS;
        int ret, i;

        for (i = 0; i < MAX_CPUS; i++) {
                /* map_fd[5] = cpus_available */
                ret = bpf_map_update_elem(map_fd[5], &i, &invalid_cpu, 0);
                if (ret) {
                        fprintf(stderr, "Failed marking CPU unavailable\n");
                        exit(EXIT_FAIL_BPF);
                }
        }
}

/* Stress cpumap management code by concurrently changing underlying cpumap */
static void stress_cpumap(void)
{
        /* Changing qsize will cause kernel to free and alloc a new
         * bpf_cpu_map_entry, with an associated/complicated tear-down
         * procedure.
         */
        create_cpu_entry(1,  1024, 0, false);
        create_cpu_entry(1,     8, 0, false);
        create_cpu_entry(1, 16000, 0, false);
}

static void stats_poll(int interval, bool use_separators, int prog_num,
                       bool stress_mode)
{
        struct stats_record *record, *prev;

        record = alloc_stats_record();
        prev   = alloc_stats_record();
        stats_collect(record);

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

        while (1) {
                swap(&prev, &record);
                stats_collect(record);
                stats_print(record, prev, prog_num);
                sleep(interval);
                if (stress_mode)
                        stress_cpumap();
        }

        free_stats_record(record);
        free_stats_record(prev);
}

int main(int argc, char **argv)
{
        struct rlimit r = {10 * 1024 * 1024, RLIM_INFINITY};
        bool use_separators = true;
        bool stress_mode = false;
        char filename[256];
        bool debug = false;
        int added_cpus = 0;
        int longindex = 0;
        int interval = 2;
        int prog_num = 5;
        int add_cpu = -1;
        __u32 qsize;
        int opt;

        /* Notice: choosing he queue size is very important with the
         * ixgbe driver, because it's driver page recycling trick is
         * dependend on pages being returned quickly.  The number of
         * out-standing packets in the system must be less-than 2x
         * RX-ring size.
         */
        qsize = 128+64;

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

        if (setrlimit(RLIMIT_MEMLOCK, &r)) {
                perror("setrlimit(RLIMIT_MEMLOCK)");
                return 1;
        }

        if (load_bpf_file(filename)) {
                fprintf(stderr, "ERR in load_bpf_file(): %s", bpf_log_buf);
                return EXIT_FAIL;
        }

        if (!prog_fd[0]) {
                fprintf(stderr, "ERR: load_bpf_file: %s\n", strerror(errno));
                return EXIT_FAIL;
        }

        mark_cpus_unavailable();

        /* Parse commands line args */
        while ((opt = getopt_long(argc, argv, "hSd:",
                                  long_options, &longindex)) != -1) {
                switch (opt) {
                case 'd':
                        if (strlen(optarg) >= IF_NAMESIZE) {
                                fprintf(stderr, "ERR: --dev name too long\n");
                                goto error;
                        }
                        ifname = (char *)&ifname_buf;
                        strncpy(ifname, optarg, IF_NAMESIZE);
                        ifindex = if_nametoindex(ifname);
                        if (ifindex == 0) {
                                fprintf(stderr,
                                        "ERR: --dev name unknown err(%d):%s\n",
                                        errno, strerror(errno));
                                goto error;
                        }
                        break;
                case 's':
                        interval = atoi(optarg);
                        break;
                case 'S':
                        xdp_flags |= XDP_FLAGS_SKB_MODE;
                        break;
                case 'D':
                        debug = true;
                        break;
                case 'x':
                        stress_mode = true;
                        break;
                case 'z':
                        use_separators = false;
                        break;
                case 'p':
                        /* Selecting eBPF prog to load */
                        prog_num = atoi(optarg);
                        if (prog_num < 0 || prog_num >= MAX_PROG) {
                                fprintf(stderr,
                                        "--prognum too large err(%d):%s\n",
                                        errno, strerror(errno));
                                goto error;
                        }
                        break;
                case 'c':
                        /* Add multiple CPUs */
                        add_cpu = strtoul(optarg, NULL, 0);
                        if (add_cpu >= MAX_CPUS) {
                                fprintf(stderr,
                                "--cpu nr too large for cpumap err(%d):%s\n",
                                        errno, strerror(errno));
                                goto error;
                        }
                        create_cpu_entry(add_cpu, qsize, added_cpus, true);
                        added_cpus++;
                        break;
                case 'q':
                        qsize = atoi(optarg);
                        break;
                case 'h':
                error:
                default:
                        usage(argv);
                        return EXIT_FAIL_OPTION;
                }
        }
        /* Required option */
        if (ifindex == -1) {
                fprintf(stderr, "ERR: required option --dev missing\n");
                usage(argv);
                return EXIT_FAIL_OPTION;
        }
        /* Required option */
        if (add_cpu == -1) {
                fprintf(stderr, "ERR: required option --cpu missing\n");
                fprintf(stderr, " Specify multiple --cpu option to add more\n");
                usage(argv);
                return EXIT_FAIL_OPTION;
        }

        /* Remove XDP program when program is interrupted or killed */
        signal(SIGINT, int_exit);
        signal(SIGTERM, int_exit);

        if (bpf_set_link_xdp_fd(ifindex, prog_fd[prog_num], xdp_flags) < 0) {
                fprintf(stderr, "link set xdp fd failed\n");
                return EXIT_FAIL_XDP;
        }

        if (debug) {
                printf("Debug-mode reading trace pipe (fix #define DEBUG)\n");
                read_trace_pipe();
        }

        stats_poll(interval, use_separators, prog_num, stress_mode);
        return EXIT_OK;
}