Function ng_ppp_newhook

freebsd/netgraph/ng_ppp.c:519–577

* Give our OK for a hook to be added */

 * Give our OK for a hook to be added
 */
static int
ng_ppp_newhook(node_p node, hook_p hook, const char *name)
{
	const priv_p priv = NG_NODE_PRIVATE(node);
	hook_p *hookPtr = NULL;
	int linkNum = -1;
	int hookIndex = -1;

	/* Figure out which hook it is */
	if (strncmp(name, NG_PPP_HOOK_LINK_PREFIX,	/* a link hook? */
	    strlen(NG_PPP_HOOK_LINK_PREFIX)) == 0) {
		const char *cp;
		char *eptr;

		cp = name + strlen(NG_PPP_HOOK_LINK_PREFIX);
		if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
			return (EINVAL);
		linkNum = (int)strtoul(cp, &eptr, 10);
		if (*eptr != '\0' || linkNum < 0 || linkNum >= NG_PPP_MAX_LINKS)
			return (EINVAL);
		hookPtr = &priv->links[linkNum].hook;
		hookIndex = ~linkNum;

		/* See if hook is already connected. */
		if (*hookPtr != NULL)
			return (EISCONN);

		/* Disallow more than one link unless multilink is enabled. */
		if (priv->links[linkNum].conf.enableLink &&
		    !priv->conf.enableMultilink && priv->numActiveLinks >= 1)
			return (ENODEV);

	} else {				/* must be a non-link hook */
		int i;

		for (i = 0; ng_ppp_hook_names[i].name != NULL; i++) {
			if (strcmp(name, ng_ppp_hook_names[i].name) == 0) {
				hookPtr = &priv->hooks[i];
				hookIndex = i;
				break;
			}
		}
		if (ng_ppp_hook_names[i].name == NULL)
			return (EINVAL);	/* no such hook */

		/* See if hook is already connected */
		if (*hookPtr != NULL)
			return (EISCONN);

		/* Every non-linkX hook have it's own function. */
		NG_HOOK_SET_RCVDATA(hook, ng_ppp_hook_names[i].fn);
	}

	/* OK */
	*hookPtr = hook;
	NG_HOOK_SET_PRIVATE(hook, (void *)(intptr_t)hookIndex);
	ng_ppp_update(node, 0);
	return (0);