examples/l2fwd-keepalive/shm.c

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

#include <time.h>

#include <rte_common.h>
#include <rte_keepalive.h>

#include "shm.h"

struct rte_keepalive_shm *rte_keepalive_shm_create(void)
{
    int fd;
    int idx_core;
    struct rte_keepalive_shm *ka_shm;

    /* If any existing object is not unlinked, it makes it all too easy
     * for clients to end up with stale shared memory blocks when
     * restarted. Unlinking makes sure subsequent shm_open by clients
     * will get the new block mapped below.
     */
    if (shm_unlink(RTE_KEEPALIVE_SHM_NAME) == -1 && errno != ENOENT)
        RTE_LOG(NOTICE, L2FWD,
            "Warning: Error unlinking stale %s (%s)\n",
            RTE_KEEPALIVE_SHM_NAME, strerror(errno));

    fd = shm_open(RTE_KEEPALIVE_SHM_NAME,
        O_CREAT | O_TRUNC | O_RDWR, 0666);
    if (fd < 0)
        RTE_LOG(ERR, L2FWD, "Failed to open %s as SHM (%s)\n",
            RTE_KEEPALIVE_SHM_NAME, strerror(errno));
    else if (ftruncate(fd, sizeof(struct rte_keepalive_shm)) != 0)
        RTE_LOG(ERR, L2FWD, "Failed to resize SHM (%s)\n", strerror(errno));
    else {
        ka_shm = (struct rte_keepalive_shm *) mmap(
            0, sizeof(struct rte_keepalive_shm),
            PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
        close(fd);
        if (ka_shm == MAP_FAILED)
            RTE_LOG(ERR, L2FWD, "Failed to mmap SHM (%s)\n", strerror(errno));
        else {
            memset(ka_shm, 0, sizeof(struct rte_keepalive_shm));

            /* Initialize the semaphores for IPC/SHM use */
            if (sem_init(&ka_shm->core_died, 1, 0) != 0) {
                RTE_LOG(ERR, L2FWD, "Failed to setup SHM semaphore (%s)\n",
                    strerror(errno));
                munmap(ka_shm,
                    sizeof(struct rte_keepalive_shm));
                return NULL;
            }

            /* Set all cores to 'not present' */
            for (idx_core = 0;
                    idx_core < RTE_KEEPALIVE_MAXCORES;
                    idx_core++) {
                ka_shm->core_state[idx_core] =
                    RTE_KA_STATE_UNUSED;
                ka_shm->core_last_seen_times[idx_core] = 0;
            }

            return ka_shm;
        }
    }
return NULL;
}

void rte_keepalive_relayed_state(struct rte_keepalive_shm *shm,
    const int id_core, const enum rte_keepalive_state core_state,
    __rte_unused uint64_t last_alive)
{
    int count;

    shm->core_state[id_core] = core_state;
    shm->core_last_seen_times[id_core] = last_alive;

    if (core_state == RTE_KEEPALIVE_SHM_DEAD) {
        /* Since core has died, also signal ka_agent.
         *
         * Limit number of times semaphore can be incremented, in case
         * ka_agent is not active.
         */
        if (sem_getvalue(&shm->core_died, &count) == -1) {
            RTE_LOG(ERR, L2FWD, "Semaphore check failed(%s)\n",
                strerror(errno));
            return;
        }
        if (count > 1)
            return;

        if (sem_post(&shm->core_died) != 0)
            RTE_LOG(ERR, L2FWD, "Failed to increment semaphore (%s)\n",
                strerror(errno));
    }
}

void rte_keepalive_shm_cleanup(struct rte_keepalive_shm *ka_shm)
{
    if (shm_unlink(RTE_KEEPALIVE_SHM_NAME) == -1 && errno != ENOENT)
        RTE_LOG(NOTICE, L2FWD, "Warning: Error unlinking  %s (%s)\n",
            RTE_KEEPALIVE_SHM_NAME, strerror(errno));

    if (ka_shm && munmap(ka_shm, sizeof(struct rte_keepalive_shm)) != 0)
        RTE_LOG(ERR, L2FWD, "Warning: munmap() failed: %s\n",
            strerror(errno));
}