Function decompose_change_notification

freebsd/net/route/route_helpers.c:224–339

#ifdef ROUTE_MPATH
static void
decompose_change_notification(struct rib_cmd_info *rc, route_notification_t *cb,
    void *cbdata)
{
	uint32_t num_old, num_new;
	uint32_t nh_idx_old, nh_idx_new;
	struct weightened_nhop *wn_old, *wn_new;
	struct weightened_nhop tmp = { NULL, 0 };
	uint32_t idx_old = 0, idx_new = 0;

	struct rib_cmd_info rc_del = { .rc_cmd = RTM_DELETE, .rc_rt = rc->rc_rt };
	struct rib_cmd_info rc_add = { .rc_cmd = RTM_ADD, .rc_rt = rc->rc_rt };

	if (NH_IS_NHGRP(rc->rc_nh_old)) {
		wn_old = nhgrp_get_nhops((struct nhgrp_object *)rc->rc_nh_old, &num_old);
	} else {
		tmp.nh = rc->rc_nh_old;
		tmp.weight = rc->rc_nh_weight;
		wn_old = &tmp;
		num_old = 1;
	}
	if (NH_IS_NHGRP(rc->rc_nh_new)) {
		wn_new = nhgrp_get_nhops((struct nhgrp_object *)rc->rc_nh_new, &num_new);
	} else {
		tmp.nh = rc->rc_nh_new;
		tmp.weight = rc->rc_nh_weight;
		wn_new = &tmp;
		num_new = 1;
	}

	/* Use the fact that each @wn array is sorted */
	/*
	 * Want to convert into set of add and delete operations
	 * [1] -> [1, 2] = A{2}
	 * [2] -> [1, 2] = A{1}
	 * [1, 2, 4]->[1, 3, 4] = A{2}, D{3}
	 * [1, 2, 4]->[1, 4] = D{2}
	 * [1, 2, 4] -> [3, 4] = D{1}, C{2,3} OR C{1,3}, D{2} OR D{1},D{2},A{3}
	 * [1, 2] -> [3, 4] =
	 *
	 */
	idx_old = 0;
	while ((idx_old < num_old) && (idx_new < num_new)) {
		nh_idx_old = wn_old[idx_old].nh->nh_priv->nh_idx;
		nh_idx_new = wn_new[idx_new].nh->nh_priv->nh_idx;

		if (nh_idx_old == nh_idx_new) {
			if (wn_old[idx_old].weight != wn_new[idx_new].weight) {
				/* Update weight by providing del/add notifications */
				rc_del.rc_nh_old = wn_old[idx_old].nh;
				rc_del.rc_nh_weight = wn_old[idx_old].weight;
				cb(&rc_del, cbdata);

				rc_add.rc_nh_new = wn_new[idx_new].nh;
				rc_add.rc_nh_weight = wn_new[idx_new].weight;
				cb(&rc_add, cbdata);
			}
			idx_old++;