Function ng_snd_item

lib/ff_ng_base.c:2230–2370

 */

int
ng_snd_item(item_p item, int flags)
{
    hook_p hook;
    node_p node;
#ifndef FSTACK
    int queue, rw;
    struct ng_queue *ngq;
#endif
    int error = 0;

    /* We are sending item, so it must be present! */
    KASSERT(item != NULL, ("ng_snd_item: item is NULL"));

#ifdef    NETGRAPH_DEBUG
    _ngi_check(item, __FILE__, __LINE__);
#endif

    /* Item was sent once more, postpone apply() call. */
    if (item->apply)
        refcount_acquire(&item->apply->refs);

    node = NGI_NODE(item);
    /* Node is never optional. */
    KASSERT(node != NULL, ("ng_snd_item: node is NULL"));

    hook = NGI_HOOK(item);
    /* Valid hook and mbuf are mandatory for data. */
    if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
        KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
        if (NGI_M(item) == NULL)
            ERROUT(EINVAL);
        CHECK_DATA_MBUF(NGI_M(item));
    }

#ifndef FSTACK
    /*
     * If the item or the node specifies single threading, force
     * writer semantics. Similarly, the node may say one hook always
     * produces writers. These are overrides.
     */
    if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
        (node->nd_flags & NGF_FORCE_WRITER) ||
        (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
        rw = NGQRW_W;
    } else {
        rw = NGQRW_R;
    }

    /*
     * If sender or receiver requests queued delivery, or call graph
     * loops back from outbound to inbound path, or stack usage
     * level is dangerous - enqueue message.
     */
    if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
        queue = 1;
    } else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
        curthread->td_ng_outbound) {