#include <linux/slab.h>
#include <linux/module.h>
#include <avm_coredump.h>

#include "conf.h"
#include "coredump.h"
#include "logdump.h"
#include "net.h"

static bool is_all_zero(u8 *buf, size_t size) {
    for (; size > 0; size--, buf++) {
        if (*buf) {
            return false;
        }
    }

    return true;
}

static int avm_coredump(struct notifier_block *this, unsigned long event, void *ptr) {
#define CHECK_FIELD(field, msg) if (is_all_zero((void*)&conf->field, sizeof(conf->field))) { pr_err(LOG_PREFIX msg); return NOTIFY_OK; }

    if (conf->crashed) {
        return NOTIFY_OK;
    }

    conf->crashed = 1;

    CHECK_FIELD(family, "no family set. Abort...");
    CHECK_FIELD(target_ip, "no target ip set. Abort...");
    CHECK_FIELD(target_mac, "no target mac set. Abort...");
    CHECK_FIELD(source_ip, "no source ip set. Abort...");
    CHECK_FIELD(source_mac, "no source mac set. Abort...");
    CHECK_FIELD(source_port, "no source port set. Abort...");

    avm_coredump_net_setup();

#if IS_MODULE(CONFIG_AVM_COREDUMP)
    if (conf->coredump_port != 0) {
        avm_coredump_coredump_do();
    }
#endif

    if (conf->logdump_port != 0) {
        avm_coredump_logdump_do();
    }

    avm_coredump_net_teardown();

#undef CHECK_FIELD
    return NOTIFY_OK;
}

static struct notifier_block panic_block = {
    .notifier_call = avm_coredump,
    .priority = 1,
};

static int avm_coredump_init(void) {
    int ret;

    conf = kzalloc(sizeof(struct avm_coredump_conf), GFP_KERNEL);
    if (conf == NULL) {
        pr_err(LOG_PREFIX "Could not allocate avm_coredump_conf");
        return -ENOMEM;
    }

    ret = avm_coredump_conf_init();
    if (ret != 0) {
        goto fail;
    }

#if IS_MODULE(CONFIG_AVM_COREDUMP)
    ret = avm_coredump_coredump_init();
    if (ret != 0) {
        goto fail;
    }
#endif

    ret = avm_coredump_logdump_init();
    if (ret != 0) {
        goto fail;
    }

    ret = avm_coredump_net_init();
    if (ret != 0) {
        goto fail;
    }

    atomic_notifier_chain_register(&panic_notifier_list, &panic_block);

#if IS_MODULE(CONFIG_AVM_COREDUMP)
    pr_err(LOG_PREFIX "Module loaded with support for coredump and logdump.\n");
#else
    pr_err(LOG_PREFIX "Builtin module with support for logdump.\n");
#endif
    return ret;

fail:
    pr_err(LOG_PREFIX "Module loading failed: %d\n", ret);
    return ret;
}

static void avm_coredump_exit(void) {
    atomic_notifier_chain_unregister(&panic_notifier_list, &panic_block);

    avm_coredump_coredump_exit();
    avm_coredump_net_exit();
    avm_coredump_conf_exit();

    kfree(conf);
    conf = NULL;

    pr_info(LOG_PREFIX "Module unloaded.\n");
}

#if IS_BUILTIN(CONFIG_AVM_COREDUMP)
pure_initcall(avm_coredump_init);
#else
module_init(avm_coredump_init);
#endif
module_exit(avm_coredump_exit);

MODULE_AUTHOR("AVM GmbH");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("AVM CoreDump over network");