examples/l2fwd-keepalive/ka-agent/main.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2016 Intel Corporation
 */

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/queue.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <time.h>

#include <rte_keepalive.h>

#include <shm.h>

#define MAX_TIMEOUTS 4
#define SEM_TIMEOUT_SECS 2

static struct rte_keepalive_shm *ka_shm_create(void)
{
    int fd = shm_open(RTE_KEEPALIVE_SHM_NAME, O_RDWR, 0666);
    size_t size = sizeof(struct rte_keepalive_shm);
    struct rte_keepalive_shm *shm;

    if (fd < 0)
        printf("Failed to open %s as SHM:%s\n",
            RTE_KEEPALIVE_SHM_NAME,
        strerror(errno));
    else {
        shm = (struct rte_keepalive_shm *) mmap(
            0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
        close(fd);
        if (shm == MAP_FAILED)
            printf("Failed to mmap SHM:%s\n", strerror(errno));
        else
            return shm;
    }

    /* Reset to zero, as it was set to MAP_FAILED aka: (void *)-1 */
    shm = 0;
    return NULL;
}

int main(void)
{
    struct rte_keepalive_shm *shm = ka_shm_create();
    struct timespec timeout = { .tv_nsec = 0 };
    int idx_core;
    int cnt_cores;
    uint64_t last_seen_alive_time = 0;
    uint64_t most_recent_alive_time;
    int cnt_timeouts = 0;
    int sem_errno;

    if (shm == NULL) {
        printf("Unable to access shared core state\n");
        return 1;
    }
    while (1) {
        most_recent_alive_time = 0;
        for (idx_core = 0; idx_core < RTE_KEEPALIVE_MAXCORES;
                idx_core++)
            if (shm->core_last_seen_times[idx_core] >
                    most_recent_alive_time)
                most_recent_alive_time =
                    shm->core_last_seen_times[idx_core];

        timeout.tv_sec = time(NULL) + SEM_TIMEOUT_SECS;
        if (sem_timedwait(&shm->core_died, &timeout) == -1) {
            /* Assume no core death signals and no change in any
             * last-seen times is the keepalive monitor itself
             * failing.
             */
            sem_errno = errno;
            last_seen_alive_time = most_recent_alive_time;
            if (sem_errno == ETIMEDOUT) {
                if (last_seen_alive_time ==
                        most_recent_alive_time &&
                        cnt_timeouts++ >
                        MAX_TIMEOUTS) {
                    printf("No updates. Exiting..\n");
                    break;
                    }
            } else
                printf("sem_timedwait() error (%s)\n",
                    strerror(sem_errno));
            continue;
        }
        cnt_timeouts = 0;

        cnt_cores = 0;
        for (idx_core = 0; idx_core < RTE_KEEPALIVE_MAXCORES;
                idx_core++)
            if (shm->core_state[idx_core] == RTE_KA_STATE_DEAD)
                cnt_cores++;
        if (cnt_cores == 0) {
            /* Can happen if core was restarted since Semaphore
             * was sent, due to agent being offline.
             */
            printf("Warning: Empty dead core report\n");
            continue;
        }

        printf("%i dead cores: ", cnt_cores);
        for (idx_core = 0;
                idx_core < RTE_KEEPALIVE_MAXCORES;
                idx_core++)
            if (shm->core_state[idx_core] == RTE_KA_STATE_DEAD)
                printf("%d, ", idx_core);
        printf("\b\b\n");
    }
    if (munmap(shm, sizeof(struct rte_keepalive_shm)) != 0)
        printf("Warning: munmap() failed\n");
    return 0;
}