/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2008 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #include <sys/param.h> #include <sys/types.h> #include <sys/systm.h> #include <sys/errno.h> #include <sys/kmem.h> #include <sys/mutex.h> #include <sys/condvar.h> #include <sys/modctl.h> #include <sys/hook_impl.h> #include <sys/sdt.h> #include <sys/cmn_err.h> /* * This file provides kernel hook framework. */ static struct modldrv modlmisc = { &mod_miscops, /* drv_modops */ "Hooks Interface v1.0", /* drv_linkinfo */ }; static struct modlinkage modlinkage = { MODREV_1, /* ml_rev */ &modlmisc, /* ml_linkage */ NULL }; /* * How it works. * ============= * Use of the hook framework here is tied up with zones - when a new zone * is created, we create a new hook_stack_t and are open to business for * allowing new hook families and their events. * * A consumer of these hooks is expected to operate in this fashion: * 1) call hook_family_add() to create a new family of hooks. It is a * current requirement that this call must be made with the value * returned from hook_stack_init, by way of infrastructure elsewhere. * 2) add events to the registered family with calls to hook_event_add. * * At this point, the structures in place should be open to others to * add hooks to the event or add notifiers for when the contents of the * hook stack changes. * * The interesting stuff happens on teardown. * * It is a requirement that the provider of hook events work in the reverse * order to the above, so that the first step is: * 1) remove events from each hook family created earlier * 2) remove hook families from the hook stack. * * When doing teardown of both events and families, a check is made to see * if either structure is still "busy". If so then a boolean flag is set to * say that the structure is condemned. The presence of this flag being set * must be checked for in _add()/_register()/ functions and a failure returned * if it is set. It is ignored by the _find() functions because they're * used by _remove()/_unregister(). While setting the condemned flag when * trying to delete a structure would normally be keyed from the presence * of a reference count being greater than 1, in this implementation there * are no reference counts required: instead the presence of objects on * linked lists is taken to mean something is still "busy." * * ONLY the caller that adds the family and the events ever has a direct * reference to the internal structures and thus ONLY it should be doing * the removal of either the event or family. In practise, what this means * is that in ip_netinfo.c, we have calls to net_protocol_register(), followed * by net_event_register() (these interface to hook_family_add() and * hook_event_add(), respectively) that are made when we create an instance * of IP and when the IP instance is shutdown/destroyed, it calls * net_event_unregister() and net_protocol_unregister(), which in turn call * hook_event_remove() and hook_family_remove() respectively. Nobody else * is entitled to call the _unregister() functions. It is imperative that * there be only one _remove() call for every _add() call. * * It is possible that code which is interfacing with this hook framework * won't do all the cleaning up that it needs to at the right time. While * we can't prevent programmers from creating memory leaks, we can synchronise * when we clean up data structures to prevent code accessing free'd memory. * * A simple diagram showing the ownership is as follows: * * Owned +--------------+ * by | hook_stack_t | * the +--------------+ * Instance | * - - - - - - - -|- - - - - - - - - - - - - - - - - - * V * Owned +-------------------+ +-------------------+ * | hook_family_int_t |---->| hook_family_int_t | * by +-------------------+ +-------------------+ * | \+---------------+ \+---------------+ * network | | hook_family_t | | hook_family_t | * V +---------------+ +---------------+ * protocol +------------------+ +------------------+ * | hook_event_int_t |---->| hook_event_int_t | * (ipv4,ipv6) +------------------+ +------------------+ * | \+--------------+ \+--------------+ * | | hook_event_t | | hook_event_t | * | +--------------+ +--------------+ * - - - - - - - -|- - - - - - - - - - - - - - - - - - * V * Owned +------------+ * | hook_int_t | * by +------------+ * \+--------+ * the consumer | hook_t | * +--------+ * * The consumers, such as IPFilter, do not have any pointers or hold any * references to hook_int_t, hook_event_t or hook_event_int_t. By placing * a hook on an event through net_hook_register(), an implicit reference * to the hook_event_int_t is returned with a successful call. Additionally, * IPFilter does not see the hook_family_int_t or hook_family_t directly. * Rather it is returned a net_handle_t (from net_protocol_lookup()) that * contains a pointer to hook_family_int_t. The structure behind the * net_handle_t (struct net_data) *is* reference counted and managed * appropriately. * * A more detailed picture that describes how the family/event structures * are linked together can be found in <sys/hook_impl.h> */ /* * Locking * ======= * The use of CVW_* macros to do locking is driven by the need to allow * recursive locking with read locks when we're processing packets. This * is necessary because various netinfo functions need to hold read locks, * by design, as they can be called in or out of packet context. */ /* * Hook internal functions */ static hook_int_t *hook_copy(hook_t *src); static hook_event_int_t *hook_event_checkdup(hook_event_t *he, hook_stack_t *hks); static hook_event_int_t *hook_event_copy(hook_event_t *src); static hook_event_int_t *hook_event_find(hook_family_int_t *hfi, char *event); static void hook_event_free(hook_event_int_t *hei, hook_family_int_t *hfi); static hook_family_int_t *hook_family_copy(hook_family_t *src); static hook_family_int_t *hook_family_find(char *family, hook_stack_t *hks); static void hook_family_free(hook_family_int_t *hfi, hook_stack_t *hks); static hook_int_t *hook_find(hook_event_int_t *hei, hook_t *h); static void hook_int_free(hook_int_t *hi, netstackid_t); static void hook_init(void); static void hook_fini(void); static void *hook_stack_init(netstackid_t stackid, netstack_t *ns); static void hook_stack_fini(netstackid_t stackid, void *arg); static void hook_stack_shutdown(netstackid_t stackid, void *arg); static int hook_insert(hook_int_head_t *head, hook_int_t *new); static void hook_insert_plain(hook_int_head_t *head, hook_int_t *new); static int hook_insert_afterbefore(hook_int_head_t *head, hook_int_t *new); static hook_int_t *hook_find_byname(hook_int_head_t *head, char *name); static void hook_event_init_kstats(hook_family_int_t *, hook_event_int_t *); static void hook_event_notify_run(hook_event_int_t *, hook_family_int_t *, char *event, char *name, hook_notify_cmd_t cmd); static void hook_init_kstats(hook_family_int_t *hfi, hook_event_int_t *hei, hook_int_t *hi); static int hook_notify_register(cvwaitlock_t *lock, hook_notify_head_t *head, hook_notify_fn_t callback, void *arg); static int hook_notify_unregister(cvwaitlock_t *lock, hook_notify_head_t *head, hook_notify_fn_t callback); static void hook_notify_run(hook_notify_head_t *head, char *family, char *event, char *name, hook_notify_cmd_t cmd); static void hook_stack_notify_run(hook_stack_t *hks, char *name, hook_notify_cmd_t cmd); static void hook_stack_remove(hook_stack_t *hks); /* * A list of the hook stacks is kept here because we need to enable * net_instance_notify_register() to be called during the creation * of a new instance. Previously hook_stack_get() would just use * the netstack functions for this work but they will return NULL * until the zone has been fully initialised. */ static hook_stack_head_t hook_stacks; static kmutex_t hook_stack_lock; /* * Module entry points. */ int _init(void) { int error; hook_init(); error = mod_install(&modlinkage); if (error != 0) hook_fini(); return (error); } int _fini(void) { int error; error = mod_remove(&modlinkage); if (error == 0) hook_fini(); return (error); } int _info(struct modinfo *modinfop) { return (mod_info(&modlinkage, modinfop)); } /* * Function: hook_init * Returns: None * Parameters: None * * Initialize hooks */ static void hook_init(void) { mutex_init(&hook_stack_lock, NULL, MUTEX_DRIVER, NULL); SLIST_INIT(&hook_stacks); /* * We want to be informed each time a stack is created or * destroyed in the kernel. */ netstack_register(NS_HOOK, hook_stack_init, hook_stack_shutdown, hook_stack_fini); } /* * Function: hook_fini * Returns: None * Parameters: None * * Deinitialize hooks */ static void hook_fini(void) { netstack_unregister(NS_HOOK); mutex_destroy(&hook_stack_lock); ASSERT(SLIST_EMPTY(&hook_stacks)); } /* * Function: hook_wait_setflag * Returns: -1 = setting flag is disallowed, 0 = flag set and did * not have to wait (ie no lock droped), 1 = flag set but * it was necessary to drop locks to set it. * Parameters: waiter(I) - control data structure * busyset(I) - set of flags that we don't want set while * we are active. * wanted(I) - flag associated with newflag to indicate * what we want to do. * newflag(I) - the new ACTIVE flag we want to set that * indicates what we are doing. * * The set of functions hook_wait_* implement an API that builds on top of * the kcondvar_t to provide controlled execution through a critical region. * For each flag that indicates work is being done (FWF_*_ACTIVE) there is * also a flag that we set to indicate that we want to do it (FWF_*_WANTED). * The combination of flags is required as when this function exits to do * the task, the structure is then free for another caller to use and * to indicate that it wants to do work. The trump flags here are those * that indicate someone wants to destroy the structure that owns this * flagwait_t. In this case, we don't try to secure the ability to run * and return with an error. * * wanted - the FWF_*_WANTED flag that describes the action being requested * busyset- the set of FWF_* flags we don't want set when we run * newflag- the FWF_*_ACTIVE flag we will set to indicate we are busy */ int hook_wait_setflag(flagwait_t *waiter, uint32_t busyset, fwflag_t wanted, fwflag_t newflag) { int waited = 0; mutex_enter(&waiter->fw_lock); if (waiter->fw_flags & FWF_DESTROY) { mutex_exit(&waiter->fw_lock); return (-1); } while (waiter->fw_flags & busyset) { waiter->fw_flags |= wanted; CVW_EXIT_WRITE(waiter->fw_owner); cv_wait(&waiter->fw_cv, &waiter->fw_lock); waited = 1; CVW_ENTER_WRITE(waiter->fw_owner); if (waiter->fw_flags & FWF_DESTROY) { waiter->fw_flags &= ~wanted; mutex_exit(&waiter->fw_lock); return (-1); } waiter->fw_flags |= wanted; } waiter->fw_flags &= ~wanted; waiter->fw_flags |= newflag; mutex_exit(&waiter->fw_lock); return (waited); } /* * Function: hook_wait_unsetflag * Returns: None * Parameters: waiter(I) - control data structure * oldflag(I) - flag to reset * * Turn off the bit that we had set to run and let others know that * they should now check to see if they can run. */ void hook_wait_unsetflag(flagwait_t *waiter, uint32_t oldflag) { mutex_enter(&waiter->fw_lock); waiter->fw_flags &= ~oldflag; cv_signal(&waiter->fw_cv); mutex_exit(&waiter->fw_lock); } /* * Function: hook_wait_destroy * Returns: None * Parameters: waiter(I) - control data structure * * Since outer locking (on fw_owner) should ensure that only one function * at a time gets to call hook_wait_destroy() on a given object, there is * no need to guard against setting FWF_DESTROY_WANTED already being set. * It is, however, necessary to wait for all activity on the owning * structure to cease. */ void hook_wait_destroy(flagwait_t *waiter) { ASSERT((waiter->fw_flags & FWF_DESTROY_WANTED) == 0); waiter->fw_flags |= FWF_DESTROY_WANTED; while (!FWF_DESTROY_OK(waiter)) { CVW_EXIT_WRITE(waiter->fw_owner); cv_wait(&waiter->fw_cv, &waiter->fw_lock); CVW_ENTER_WRITE(waiter->fw_owner); } /* * There should now be nothing else using "waiter" or its * owner, so we can safely assign here without risk of wiiping * out someone's bit. */ waiter->fw_flags = FWF_DESTROY_ACTIVE; } /* * Function: hook_wait_init * Returns: None * Parameters: waiter(I) - control data structure * ownder(I) - pointer to lock that the owner of this * waiter uses * * "owner" gets passed in here so that when we need to call cv_wait, * for example in hook_wait_setflag(), we can drop the lock for the * next layer out, which is likely to be held in an exclusive manner. */ void hook_wait_init(flagwait_t *waiter, cvwaitlock_t *owner) { cv_init(&waiter->fw_cv, NULL, CV_DRIVER, NULL); mutex_init(&waiter->fw_lock, NULL, MUTEX_DRIVER, NULL); waiter->fw_flags = FWF_NONE; waiter->fw_owner = owner; } /* * Initialize the hook stack instance. */ /*ARGSUSED*/ static void * hook_stack_init(netstackid_t stackid, netstack_t *ns) { hook_stack_t *hks; #ifdef NS_DEBUG printf("hook_stack_init(stack %d)\n", stackid); #endif hks = (hook_stack_t *)kmem_zalloc(sizeof (*hks), KM_SLEEP); hks->hks_netstack = ns; hks->hks_netstackid = stackid; CVW_INIT(&hks->hks_lock); TAILQ_INIT(&hks->hks_nhead); SLIST_INIT(&hks->hks_familylist); hook_wait_init(&hks->hks_waiter, &hks->hks_lock); mutex_enter(&hook_stack_lock); SLIST_INSERT_HEAD(&hook_stacks, hks, hks_entry); mutex_exit(&hook_stack_lock); return (hks); } /* * Set the shutdown flag to indicate that we should stop accepting new * register calls as we're now in the cleanup process. */ /*ARGSUSED*/ static void hook_stack_shutdown(netstackid_t stackid, void *arg) { hook_stack_t *hks = (hook_stack_t *)arg; mutex_enter(&hook_stack_lock); /* * Once this flag gets set to one, no more additions are allowed * to any of the structures that make up this stack. */ hks->hks_shutdown = 1; mutex_exit(&hook_stack_lock); } /* * Free the hook stack instance. */ /*ARGSUSED*/ static void hook_stack_fini(netstackid_t stackid, void *arg) { hook_stack_t *hks = (hook_stack_t *)arg; mutex_enter(&hook_stack_lock); hks->hks_shutdown = 2; hook_stack_remove(hks); mutex_exit(&hook_stack_lock); } /* * This function assumes that it is called with hook_stack_lock held. * It functions differently to hook_family/event_remove in that it does * the checks to see if it can be removed. This difference exists * because this structure has nothing higher up that depends on it. */ static void hook_stack_remove(hook_stack_t *hks) { ASSERT(mutex_owned(&hook_stack_lock)); /* * Is the structure still in use? */ if (!SLIST_EMPTY(&hks->hks_familylist) || !TAILQ_EMPTY(&hks->hks_nhead)) return; SLIST_REMOVE(&hook_stacks, hks, hook_stack, hks_entry); hook_wait_destroy(&hks->hks_waiter); CVW_DESTROY(&hks->hks_lock); kmem_free(hks, sizeof (*hks)); } static hook_stack_t * hook_stack_get(netstackid_t stackid) { hook_stack_t *hks; SLIST_FOREACH(hks, &hook_stacks, hks_entry) { if (hks->hks_netstackid == stackid) break; } return (hks); } /* * Function: hook_stack_notify_register * Returns: 0 = success, else failure * Parameters: stackid(I) - netstack identifier * callback(I)- function to be called * arg(I) - arg to provide callback when it is called * * If we're not shutting down this instance, append a new function to the * list of those to call when a new family of hooks is added to this stack. */ int hook_stack_notify_register(netstackid_t stackid, hook_notify_fn_t callback, void *arg) { hook_stack_t *hks; int error; mutex_enter(&hook_stack_lock); hks = hook_stack_get(stackid); if (hks != NULL) { if (hks->hks_shutdown != 0) { error = ESHUTDOWN; } else { error = hook_notify_register(&hks->hks_lock, &hks->hks_nhead, callback, arg); } } else { error = ESRCH; } mutex_exit(&hook_stack_lock); return (error); } /* * Function: hook_stack_notify_unregister * Returns: 0 = success, else failure * Parameters: stackid(I) - netstack identifier * callback(I) - function to be called * * Attempt to remove a registered function from a hook stack's list of * callbacks to activiate when protocols are added/deleted. */ int hook_stack_notify_unregister(netstackid_t stackid, hook_notify_fn_t callback) { hook_stack_t *hks; int error; mutex_enter(&hook_stack_lock); hks = hook_stack_get(stackid); if (hks != NULL) { error = hook_notify_unregister(&hks->hks_lock, &hks->hks_nhead, callback); if ((error == 0) && (hks->hks_shutdown == 2)) hook_stack_remove(hks); } else { error = ESRCH; } mutex_exit(&hook_stack_lock); return (error); } /* * Function: hook_stack_notify_run * Returns: None * Parameters: hks(I) - hook stack pointer to execute callbacks for * name(I) - name of a hook family * cmd(I) - either HN_UNREGISTER or HN_REGISTER * * Run through the list of callbacks on the hook stack to be called when * a new hook family is added * * As hook_notify_run() expects 3 names, one for the family, one for the * event and one for the object being introduced and we really only have * one name (that of the new hook family), fake the hook stack's name by * converting the integer to a string and for the event just pass NULL. */ static void hook_stack_notify_run(hook_stack_t *hks, char *name, hook_notify_cmd_t cmd) { char buffer[16]; (void) snprintf(buffer, sizeof (buffer), "%u", hks->hks_netstackid); hook_notify_run(&hks->hks_nhead, buffer, NULL, name, cmd); } /* * Function: hook_run * Returns: int - return value according to callback func * Parameters: token(I) - event pointer * info(I) - message * * Run hooks for specific provider. The hooks registered are stepped through * until either the end of the list is reached or a hook function returns a * non-zero value. If a non-zero value is returned from a hook function, we * return that value back to our caller. By design, a hook function can be * called more than once, simultaneously. */ int hook_run(hook_family_int_t *hfi, hook_event_token_t token, hook_data_t info) { hook_event_int_t *hei; hook_int_t *hi; int rval = 0; ASSERT(token != NULL); hei = (hook_event_int_t *)token; DTRACE_PROBE2(hook__run__start, hook_event_token_t, token, hook_data_t, info); /* * Hold global read lock to ensure event will not be deleted. * While it might be expected that we should also hold a read lock * on the event lock (hei_lock) to prevent the hook list from * changing while we're executing this function, both addition * to and removal from the hook list on the event is done with * a write lock held on hfi_lock. This is by design so that we * only need to get one of these locks to process a packet. * - locking is not a cheap thing to do for every packet. */ CVW_ENTER_READ(&hfi->hfi_lock); TAILQ_FOREACH(hi, &hei->hei_head, hi_entry) { ASSERT(hi->hi_hook.h_func != NULL); DTRACE_PROBE3(hook__func__start, hook_event_token_t, token, hook_data_t, info, hook_int_t *, hi); rval = (*hi->hi_hook.h_func)(token, info, hi->hi_hook.h_arg); DTRACE_PROBE4(hook__func__end, hook_event_token_t, token, hook_data_t, info, hook_int_t *, hi, int, rval); hi->hi_kstats.hook_hits.value.ui64++; if (rval != 0) break; } hei->hei_kstats.events.value.ui64++; CVW_EXIT_READ(&hfi->hfi_lock); DTRACE_PROBE3(hook__run__end, hook_event_token_t, token, hook_data_t, info, hook_int_t *, hi); return (rval); } /* * Function: hook_family_add * Returns: internal family pointer - NULL = Fail * Parameters: hf(I) - family pointer * * Add new family to family list */ hook_family_int_t * hook_family_add(hook_family_t *hf, hook_stack_t *hks) { hook_family_int_t *hfi, *new; ASSERT(hf != NULL); ASSERT(hf->hf_name != NULL); new = hook_family_copy(hf); if (new == NULL) return (NULL); mutex_enter(&hook_stack_lock); CVW_ENTER_WRITE(&hks->hks_lock); if (hks->hks_shutdown != 0) { CVW_EXIT_WRITE(&hks->hks_lock); mutex_exit(&hook_stack_lock); hook_family_free(new, NULL); return (NULL); } /* search family list */ hfi = hook_family_find(hf->hf_name, hks); if (hfi != NULL) { CVW_EXIT_WRITE(&hks->hks_lock); mutex_exit(&hook_stack_lock); hook_family_free(new, NULL); return (NULL); } if (hook_wait_setflag(&hks->hks_waiter, FWF_WAIT_MASK, FWF_ADD_WANTED, FWF_ADD_ACTIVE) == -1) { CVW_EXIT_WRITE(&hks->hks_lock); mutex_exit(&hook_stack_lock); hook_family_free(new, NULL); return (NULL); } CVW_INIT(&new->hfi_lock); SLIST_INIT(&new->hfi_head); TAILQ_INIT(&new->hfi_nhead); hook_wait_init(&new->hfi_waiter, &new->hfi_lock); new->hfi_stack = hks; /* Add to family list head */ SLIST_INSERT_HEAD(&hks->hks_familylist, new, hfi_entry); CVW_EXIT_WRITE(&hks->hks_lock); mutex_exit(&hook_stack_lock); hook_stack_notify_run(hks, hf->hf_name, HN_REGISTER); hook_wait_unsetflag(&hks->hks_waiter, FWF_ADD_ACTIVE); return (new); } /* * Function: hook_family_remove * Returns: int - 0 = Succ, Else = Fail * Parameters: hfi(I) - internal family pointer * * Remove family from family list. This function has been designed to be * called once and once only per hook_family_int_t. Thus when cleaning up * this structure as an orphan, callers should only call hook_family_free. */ int hook_family_remove(hook_family_int_t *hfi) { hook_stack_t *hks; boolean_t notifydone; ASSERT(hfi != NULL); hks = hfi->hfi_stack; CVW_ENTER_WRITE(&hks->hks_lock); if (hook_wait_setflag(&hks->hks_waiter, FWF_WAIT_MASK, FWF_DEL_WANTED, FWF_DEL_ACTIVE) == -1) { /* * If we're trying to destroy the hook_stack_t... */ CVW_EXIT_WRITE(&hks->hks_lock); return (ENXIO); } /* * Check if the family is in use by the presence of either events * or notify callbacks on the hook family. */ if (!SLIST_EMPTY(&hfi->hfi_head) || !TAILQ_EMPTY(&hfi->hfi_nhead)) { hfi->hfi_condemned = B_TRUE; } else { /* * Although hfi_condemned = B_FALSE is implied from creation, * putting a comment here inside the else upsets lint. */ hfi->hfi_condemned = B_FALSE; } CVW_ENTER_WRITE(&hfi->hfi_lock); hook_wait_destroy(&hfi->hfi_waiter); notifydone = hfi->hfi_shutdown; hfi->hfi_shutdown = B_TRUE; CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_WRITE(&hks->hks_lock); if (!notifydone) hook_stack_notify_run(hks, hfi->hfi_family.hf_name, HN_UNREGISTER); hook_wait_unsetflag(&hks->hks_waiter, FWF_DEL_ACTIVE); /* * If we don't have to wait for anything else to disappear from this * structure then we can free it up. */ if (!hfi->hfi_condemned) hook_family_free(hfi, hks); return (0); } /* * Function: hook_family_free * Returns: None * Parameters: hfi(I) - internal family pointer * * Free alloc memory for family */ static void hook_family_free(hook_family_int_t *hfi, hook_stack_t *hks) { /* * This lock gives us possession of the hks pointer after the * SLIST_REMOVE, for which it is not needed, when hks_shutdown * is checked and hook_stack_remove called. */ mutex_enter(&hook_stack_lock); ASSERT(hfi != NULL); if (hks != NULL) { CVW_ENTER_WRITE(&hks->hks_lock); /* Remove from family list */ SLIST_REMOVE(&hks->hks_familylist, hfi, hook_family_int, hfi_entry); CVW_EXIT_WRITE(&hks->hks_lock); } /* Free name space */ if (hfi->hfi_family.hf_name != NULL) { kmem_free(hfi->hfi_family.hf_name, strlen(hfi->hfi_family.hf_name) + 1); } /* Free container */ kmem_free(hfi, sizeof (*hfi)); if (hks->hks_shutdown == 2) hook_stack_remove(hks); mutex_exit(&hook_stack_lock); } /* * Function: hook_family_shutdown * Returns: int - 0 = Succ, Else = Fail * Parameters: hfi(I) - internal family pointer * * As an alternative to removing a family, we may desire to just generate * a series of callbacks to indicate that we will be going away in the * future. The hfi_condemned flag isn't set because we aren't trying to * remove the structure. */ int hook_family_shutdown(hook_family_int_t *hfi) { hook_stack_t *hks; boolean_t notifydone; ASSERT(hfi != NULL); hks = hfi->hfi_stack; CVW_ENTER_WRITE(&hks->hks_lock); if (hook_wait_setflag(&hks->hks_waiter, FWF_WAIT_MASK, FWF_DEL_WANTED, FWF_DEL_ACTIVE) == -1) { /* * If we're trying to destroy the hook_stack_t... */ CVW_EXIT_WRITE(&hks->hks_lock); return (ENXIO); } CVW_ENTER_WRITE(&hfi->hfi_lock); notifydone = hfi->hfi_shutdown; hfi->hfi_shutdown = B_TRUE; CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_WRITE(&hks->hks_lock); if (!notifydone) hook_stack_notify_run(hks, hfi->hfi_family.hf_name, HN_UNREGISTER); hook_wait_unsetflag(&hks->hks_waiter, FWF_DEL_ACTIVE); return (0); } /* * Function: hook_family_copy * Returns: internal family pointer - NULL = Failed * Parameters: src(I) - family pointer * * Allocate internal family block and duplicate incoming family * No locks should be held across this function as it may sleep. */ static hook_family_int_t * hook_family_copy(hook_family_t *src) { hook_family_int_t *new; hook_family_t *dst; ASSERT(src != NULL); ASSERT(src->hf_name != NULL); new = (hook_family_int_t *)kmem_zalloc(sizeof (*new), KM_SLEEP); /* Copy body */ dst = &new->hfi_family; *dst = *src; SLIST_INIT(&new->hfi_head); TAILQ_INIT(&new->hfi_nhead); /* Copy name */ dst->hf_name = (char *)kmem_alloc(strlen(src->hf_name) + 1, KM_SLEEP); (void) strcpy(dst->hf_name, src->hf_name); return (new); } /* * Function: hook_family_find * Returns: internal family pointer - NULL = Not match * Parameters: family(I) - family name string * * Search family list with family name * A lock on hfi_lock must be held when called. */ static hook_family_int_t * hook_family_find(char *family, hook_stack_t *hks) { hook_family_int_t *hfi = NULL; ASSERT(family != NULL); SLIST_FOREACH(hfi, &hks->hks_familylist, hfi_entry) { if (strcmp(hfi->hfi_family.hf_name, family) == 0) break; } return (hfi); } /* * Function: hook_family_notify_register * Returns: 0 = success, else failure * Parameters: hfi(I) - hook family * callback(I) - function to be called * arg(I) - arg to provide callback when it is called * * So long as this hook stack isn't being shut down, register a new * callback to be activated each time a new event is added to this * family. * * To call this function we must have an active handle in use on the family, * so if we take this into account, then neither the hook_family_int_t nor * the hook_stack_t that owns it can disappear. We have to put some trust * in the callers to be properly synchronised... * * Holding hks_lock is required to provide synchronisation for hks_shutdown. */ int hook_family_notify_register(hook_family_int_t *hfi, hook_notify_fn_t callback, void *arg) { hook_stack_t *hks; int error; hks = hfi->hfi_stack; CVW_ENTER_READ(&hks->hks_lock); CVW_ENTER_WRITE(&hfi->hfi_lock); if ((hfi->hfi_stack->hks_shutdown != 0) || hfi->hfi_condemned || hfi->hfi_shutdown) { CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); return (ESHUTDOWN); } error = hook_notify_register(&hfi->hfi_lock, &hfi->hfi_nhead, callback, arg); CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); return (error); } /* * Function: hook_family_notify_unregister * Returns: 0 = success, else failure * Parameters: hfi(I) - hook family * callback(I) - function to be called * * Remove a callback from the list of those executed when a new event is * added to a hook family. */ int hook_family_notify_unregister(hook_family_int_t *hfi, hook_notify_fn_t callback) { boolean_t free_family; int error; CVW_ENTER_WRITE(&hfi->hfi_lock); error = hook_notify_unregister(&hfi->hfi_lock, &hfi->hfi_nhead, callback); /* * If hook_family_remove has been called but the structure was still * "busy" ... but we might have just made it "unbusy"... */ if ((error == 0) && hfi->hfi_condemned && SLIST_EMPTY(&hfi->hfi_head) && TAILQ_EMPTY(&hfi->hfi_nhead)) { free_family = B_TRUE; } else { free_family = B_FALSE; } CVW_EXIT_WRITE(&hfi->hfi_lock); if (free_family) hook_family_free(hfi, hfi->hfi_stack); return (error); } /* * Function: hook_event_add * Returns: internal event pointer - NULL = Fail * Parameters: hfi(I) - internal family pointer * he(I) - event pointer * * Add new event to event list on specific family. * This function can fail to return successfully if (1) it cannot allocate * enough memory for its own internal data structures, (2) the event has * already been registered (for any hook family.) */ hook_event_int_t * hook_event_add(hook_family_int_t *hfi, hook_event_t *he) { hook_event_int_t *hei, *new; hook_stack_t *hks; ASSERT(hfi != NULL); ASSERT(he != NULL); ASSERT(he->he_name != NULL); new = hook_event_copy(he); if (new == NULL) return (NULL); hks = hfi->hfi_stack; CVW_ENTER_READ(&hks->hks_lock); hks = hfi->hfi_stack; if (hks->hks_shutdown != 0) { CVW_EXIT_READ(&hks->hks_lock); hook_event_free(new, NULL); return (NULL); } /* Check whether this event pointer is already registered */ hei = hook_event_checkdup(he, hks); if (hei != NULL) { CVW_EXIT_READ(&hks->hks_lock); hook_event_free(new, NULL); return (NULL); } CVW_ENTER_WRITE(&hfi->hfi_lock); if (hfi->hfi_condemned || hfi->hfi_shutdown) { CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); hook_event_free(new, NULL); return (NULL); } if (hook_wait_setflag(&hfi->hfi_waiter, FWF_WAIT_MASK, FWF_ADD_WANTED, FWF_ADD_ACTIVE) == -1) { CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); hook_event_free(new, NULL); return (NULL); } TAILQ_INIT(&new->hei_nhead); hook_event_init_kstats(hfi, new); hook_wait_init(&new->hei_waiter, &new->hei_lock); /* Add to event list head */ SLIST_INSERT_HEAD(&hfi->hfi_head, new, hei_entry); CVW_EXIT_WRITE(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); hook_notify_run(&hfi->hfi_nhead, hfi->hfi_family.hf_name, NULL, he->he_name, HN_REGISTER); hook_wait_unsetflag(&hfi->hfi_waiter, FWF_ADD_ACTIVE); return (new); } /* * Function: hook_event_init_kstats * Returns: None * Parameters: hfi(I) - pointer to the family that owns this event. * hei(I) - pointer to the hook event that needs some kstats. * * Create a set of kstats that relate to each event registered with * the hook framework. A counter is kept for each time the event is * activated and for each time a hook is added or removed. As the * kstats just count the events as they happen, the total number of * hooks registered must be obtained by subtractived removed from added. */ static void hook_event_init_kstats(hook_family_int_t *hfi, hook_event_int_t *hei) { hook_event_kstat_t template = { { "hooksAdded", KSTAT_DATA_UINT64 }, { "hooksRemoved", KSTAT_DATA_UINT64 }, { "events", KSTAT_DATA_UINT64 } }; hook_stack_t *hks; hks = hfi->hfi_stack; hei->hei_kstatp = kstat_create_netstack(hfi->hfi_family.hf_name, 0, hei->hei_event->he_name, "hook_event", KSTAT_TYPE_NAMED, sizeof (hei->hei_kstats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL, hks->hks_netstackid); bcopy((char *)&template, &hei->hei_kstats, sizeof (template)); if (hei->hei_kstatp != NULL) { hei->hei_kstatp->ks_data = (void *)&hei->hei_kstats; hei->hei_kstatp->ks_private = (void *)(uintptr_t)hks->hks_netstackid; kstat_install(hei->hei_kstatp); } } /* * Function: hook_event_remove * Returns: int - 0 = Succ, Else = Fail * Parameters: hfi(I) - internal family pointer * he(I) - event pointer * * Remove event from event list on specific family * * This function assumes that the caller has received a pointer to a the * hook_family_int_t via a call to net_protocol_lookup or net_protocol_unreg'. * This the hook_family_int_t is guaranteed to be around for the life of this * call, unless the caller has decided to call net_protocol_release or * net_protocol_unregister before calling net_event_unregister - an error. */ int hook_event_remove(hook_family_int_t *hfi, hook_event_t *he) { boolean_t free_family; hook_event_int_t *hei; boolean_t notifydone; ASSERT(hfi != NULL); ASSERT(he != NULL); CVW_ENTER_WRITE(&hfi->hfi_lock); /* * Set the flag so that we can call hook_event_notify_run without * holding any locks but at the same time prevent other changes to * the event at the same time. */ if (hook_wait_setflag(&hfi->hfi_waiter, FWF_WAIT_MASK, FWF_DEL_WANTED, FWF_DEL_ACTIVE) == -1) { CVW_EXIT_WRITE(&hfi->hfi_lock); return (ENXIO); } hei = hook_event_find(hfi, he->he_name); if (hei == NULL) { hook_wait_unsetflag(&hfi->hfi_waiter, FWF_DEL_ACTIVE); CVW_EXIT_WRITE(&hfi->hfi_lock); return (ESRCH); } free_family = B_FALSE; CVW_ENTER_WRITE(&hei->hei_lock); /* * The hei_shutdown flag is used to indicate whether or not we have * done a shutdown and thus already walked through the notify list. */ notifydone = hei->hei_shutdown; hei->hei_shutdown = B_TRUE; /* * If there are any hooks still registered for this event or * there are any notifiers registered, return an error indicating * that the event is still busy. */ if (!TAILQ_EMPTY(&hei->hei_head) || !TAILQ_EMPTY(&hei->hei_nhead)) { hei->hei_condemned = B_TRUE; CVW_EXIT_WRITE(&hei->hei_lock); } else { /* hei_condemned = B_FALSE is implied from creation */ /* * Even though we know the notify list is empty, we call * hook_wait_destroy here to synchronise wait removing a * hook from an event. */ hook_wait_destroy(&hei->hei_waiter); CVW_EXIT_WRITE(&hei->hei_lock); if (hfi->hfi_condemned && SLIST_EMPTY(&hfi->hfi_head) && TAILQ_EMPTY(&hfi->hfi_nhead)) free_family = B_TRUE; } CVW_EXIT_WRITE(&hfi->hfi_lock); if (!notifydone) hook_notify_run(&hfi->hfi_nhead, hfi->hfi_family.hf_name, NULL, he->he_name, HN_UNREGISTER); hook_wait_unsetflag(&hfi->hfi_waiter, FWF_DEL_ACTIVE); if (!hei->hei_condemned) { hook_event_free(hei, hfi); if (free_family) hook_family_free(hfi, hfi->hfi_stack); } return (0); } /* * Function: hook_event_shutdown * Returns: int - 0 = Succ, Else = Fail * Parameters: hfi(I) - internal family pointer * he(I) - event pointer * * As with hook_family_shutdown, we want to generate the notify callbacks * as if the event was being removed but not actually do the remove. */ int hook_event_shutdown(hook_family_int_t *hfi, hook_event_t *he) { hook_event_int_t *hei; boolean_t notifydone; ASSERT(hfi != NULL); ASSERT(he != NULL); CVW_ENTER_WRITE(&hfi->hfi_lock); /* * Set the flag so that we can call hook_event_notify_run without * holding any locks but at the same time prevent other changes to * the event at the same time. */ if (hook_wait_setflag(&hfi->hfi_waiter, FWF_WAIT_MASK, FWF_DEL_WANTED, FWF_DEL_ACTIVE) == -1) { CVW_EXIT_WRITE(&hfi->hfi_lock); return (ENXIO); } hei = hook_event_find(hfi, he->he_name); if (hei == NULL) { hook_wait_unsetflag(&hfi->hfi_waiter, FWF_DEL_ACTIVE); CVW_EXIT_WRITE(&hfi->hfi_lock); return (ESRCH); } CVW_ENTER_WRITE(&hei->hei_lock); notifydone = hei->hei_shutdown; hei->hei_shutdown = B_TRUE; CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_WRITE(&hfi->hfi_lock); if (!notifydone) hook_notify_run(&hfi->hfi_nhead, hfi->hfi_family.hf_name, NULL, he->he_name, HN_UNREGISTER); hook_wait_unsetflag(&hfi->hfi_waiter, FWF_DEL_ACTIVE); return (0); } /* * Function: hook_event_free * Returns: None * Parameters: hei(I) - internal event pointer * * Free alloc memory for event */ static void hook_event_free(hook_event_int_t *hei, hook_family_int_t *hfi) { boolean_t free_family; ASSERT(hei != NULL); if (hfi != NULL) { CVW_ENTER_WRITE(&hfi->hfi_lock); /* * Remove the event from the hook family's list. */ SLIST_REMOVE(&hfi->hfi_head, hei, hook_event_int, hei_entry); if (hfi->hfi_condemned && SLIST_EMPTY(&hfi->hfi_head) && TAILQ_EMPTY(&hfi->hfi_nhead)) { free_family = B_TRUE; } else { free_family = B_FALSE; } CVW_EXIT_WRITE(&hfi->hfi_lock); } if (hei->hei_kstatp != NULL) { ASSERT(hfi != NULL); kstat_delete_netstack(hei->hei_kstatp, hfi->hfi_stack->hks_netstackid); hei->hei_kstatp = NULL; } /* Free container */ kmem_free(hei, sizeof (*hei)); if (free_family) hook_family_free(hfi, hfi->hfi_stack); } /* * Function: hook_event_checkdup * Returns: internal event pointer - NULL = Not match * Parameters: he(I) - event pointer * * Search all of the hook families to see if the event being passed in * has already been associated with one. */ static hook_event_int_t * hook_event_checkdup(hook_event_t *he, hook_stack_t *hks) { hook_family_int_t *hfi; hook_event_int_t *hei; ASSERT(he != NULL); CVW_ENTER_READ(&hks->hks_lock); SLIST_FOREACH(hfi, &hks->hks_familylist, hfi_entry) { SLIST_FOREACH(hei, &hfi->hfi_head, hei_entry) { if (hei->hei_event == he) { CVW_EXIT_READ(&hks->hks_lock); return (hei); } } } CVW_EXIT_READ(&hks->hks_lock); return (NULL); } /* * Function: hook_event_copy * Returns: internal event pointer - NULL = Failed * Parameters: src(I) - event pointer * * Allocate internal event block and duplicate incoming event * No locks should be held across this function as it may sleep. */ static hook_event_int_t * hook_event_copy(hook_event_t *src) { hook_event_int_t *new; ASSERT(src != NULL); ASSERT(src->he_name != NULL); new = (hook_event_int_t *)kmem_zalloc(sizeof (*new), KM_SLEEP); /* Copy body */ TAILQ_INIT(&new->hei_head); new->hei_event = src; return (new); } /* * Function: hook_event_find * Returns: internal event pointer - NULL = Not match * Parameters: hfi(I) - internal family pointer * event(I) - event name string * * Search event list with event name * A lock on hfi->hfi_lock must be held when called. */ static hook_event_int_t * hook_event_find(hook_family_int_t *hfi, char *event) { hook_event_int_t *hei = NULL; ASSERT(hfi != NULL); ASSERT(event != NULL); SLIST_FOREACH(hei, &hfi->hfi_head, hei_entry) { if ((strcmp(hei->hei_event->he_name, event) == 0) && ((hei->hei_waiter.fw_flags & FWF_UNSAFE) == 0)) break; } return (hei); } /* * Function: hook_event_notify_register * Returns: 0 = success, else failure * Parameters: hfi(I) - hook family * event(I) - name of the event * callback(I) - function to be called * arg(I) - arg to provide callback when it is called * * Adds a new callback to the event named by "event" (we must find it) * that will be executed each time a new hook is added to the event. * Of course, if the stack is being shut down, this call should fail. */ int hook_event_notify_register(hook_family_int_t *hfi, char *event, hook_notify_fn_t callback, void *arg) { hook_event_int_t *hei; hook_stack_t *hks; int error; hks = hfi->hfi_stack; CVW_ENTER_READ(&hks->hks_lock); if (hks->hks_shutdown != 0) { CVW_EXIT_READ(&hks->hks_lock); return (ESHUTDOWN); } CVW_ENTER_READ(&hfi->hfi_lock); if (hfi->hfi_condemned || hfi->hfi_shutdown) { CVW_EXIT_READ(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); return (ESHUTDOWN); } hei = hook_event_find(hfi, event); if (hei == NULL) { CVW_EXIT_READ(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); return (ESRCH); } /* * Grabbing the read lock on hei_lock is only so that we can * synchronise access to hei_condemned. */ CVW_ENTER_WRITE(&hei->hei_lock); if (hei->hei_condemned || hei->hei_shutdown) { CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_READ(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); return (ESHUTDOWN); } error = hook_notify_register(&hei->hei_lock, &hei->hei_nhead, callback, arg); CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_READ(&hfi->hfi_lock); CVW_EXIT_READ(&hks->hks_lock); return (error); } /* * Function: hook_event_notify_unregister * Returns: 0 = success, else failure * Parameters: hfi(I) - hook family * event(I) - name of the event * callback(I) - function to be called * * Remove the given callback from the named event's list of functions * to call when a hook is added or removed. */ int hook_event_notify_unregister(hook_family_int_t *hfi, char *event, hook_notify_fn_t callback) { hook_event_int_t *hei; boolean_t free_event; int error; CVW_ENTER_READ(&hfi->hfi_lock); hei = hook_event_find(hfi, event); if (hei == NULL) { CVW_EXIT_READ(&hfi->hfi_lock); return (ESRCH); } CVW_ENTER_WRITE(&hei->hei_lock); error = hook_notify_unregister(&hei->hei_lock, &hei->hei_nhead, callback); /* * hei_condemned has been set if someone tried to remove the * event but couldn't because there were still things attached to * it. Now that we've done a successful remove, if it is now empty * then by all rights we should be free'ing it too. Note that the * expectation is that only the caller of hook_event_add will ever * call hook_event_remove. */ if ((error == 0) && hei->hei_condemned && TAILQ_EMPTY(&hei->hei_head) && TAILQ_EMPTY(&hei->hei_nhead)) { free_event = B_TRUE; } else { free_event = B_FALSE; } CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_READ(&hfi->hfi_lock); if (free_event) { /* * It is safe to pass in hfi here, without a lock, because * our structure (hei) is still on one of its lists and thus * it won't be able to disappear yet... */ hook_event_free(hei, hfi); } return (error); } /* * Function: hook_event_notify_run * Returns: None * Parameters: nrun(I) - pointer to the list of callbacks to execute * hfi(I) - hook stack pointer to execute callbacks for * name(I) - name of a hook family * cmd(I) - either HN_UNREGISTER or HN_REGISTER * * Execute all of the callbacks registered for this event. */ static void hook_event_notify_run(hook_event_int_t *hei, hook_family_int_t *hfi, char *event, char *name, hook_notify_cmd_t cmd) { hook_notify_run(&hei->hei_nhead, hfi->hfi_family.hf_name, event, name, cmd); } /* * Function: hook_register * Returns: int- 0 = Succ, Else = Fail * Parameters: hfi(I) - internal family pointer * event(I) - event name string * h(I) - hook pointer * * Add new hook to hook list on the specified family and event. */ int hook_register(hook_family_int_t *hfi, char *event, hook_t *h) { hook_event_int_t *hei; hook_int_t *hi, *new; int error; ASSERT(hfi != NULL); ASSERT(event != NULL); ASSERT(h != NULL); if (hfi->hfi_stack->hks_shutdown) return (NULL); /* Alloc hook_int_t and copy hook */ new = hook_copy(h); if (new == NULL) return (ENOMEM); /* * Since hook add/remove only impact event, so it is unnecessary * to hold global family write lock. Just get read lock here to * ensure event will not be removed when doing hooks operation */ CVW_ENTER_WRITE(&hfi->hfi_lock); hei = hook_event_find(hfi, event); if (hei == NULL) { CVW_EXIT_WRITE(&hfi->hfi_lock); hook_int_free(new, hfi->hfi_stack->hks_netstackid); return (ENXIO); } CVW_ENTER_WRITE(&hei->hei_lock); /* * If we've run either the remove() or shutdown(), do not allow any * more hooks to be added to this event. */ if (hei->hei_shutdown) { error = ESHUTDOWN; goto bad_add; } hi = hook_find(hei, h); if (hi != NULL) { error = EEXIST; goto bad_add; } if (hook_wait_setflag(&hei->hei_waiter, FWF_WAIT_MASK, FWF_ADD_WANTED, FWF_ADD_ACTIVE) == -1) { error = ENOENT; bad_add: CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_WRITE(&hfi->hfi_lock); hook_int_free(new, hfi->hfi_stack->hks_netstackid); return (error); } /* Add to hook list head */ error = hook_insert(&hei->hei_head, new); if (error == 0) { hei->hei_event->he_interested = B_TRUE; hei->hei_kstats.hooks_added.value.ui64++; hook_init_kstats(hfi, hei, new); } CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_WRITE(&hfi->hfi_lock); /* * Note that the name string passed through to the notify callbacks * is from the original hook being registered, not the copy being * inserted. */ if (error == 0) { hook_event_notify_run(hei, hfi, event, h->h_name, HN_REGISTER); hook_wait_unsetflag(&hei->hei_waiter, FWF_ADD_ACTIVE); } return (error); } /* * Function: hook_insert * Returns: int- 0 = Succ, else = Fail * Parameters: head(I) - pointer to hook list to insert hook onto * new(I) - pointer to hook to be inserted * * Try to insert the hook onto the list of hooks according to the hints * given in the hook to be inserted and those that already exist on the * list. For now, the implementation permits only a single hook to be * either first or last and names provided with before or after are only * loosely coupled with the action. */ static int hook_insert(hook_int_head_t *head, hook_int_t *new) { hook_int_t *before; hook_int_t *hi; hook_t *hih; hook_t *h = &new->hi_hook; switch (new->hi_hook.h_hint) { case HH_NONE : before = NULL; /* * If there is no hint present (or not one that can be * satisfied now) then try to at least respect the wishes * of those that want to be last. If there are none wanting * to be last then add the new hook to the tail of the * list - this means we keep any wanting to be first * happy without having to search for HH_FIRST. */ TAILQ_FOREACH(hi, head, hi_entry) { hih = &hi->hi_hook; if ((hih->h_hint == HH_AFTER) && (strcmp(h->h_name, (char *)hih->h_hintvalue) == 0)) { TAILQ_INSERT_BEFORE(hi, new, hi_entry); return (0); } if ((hih->h_hint == HH_BEFORE) && (before == NULL) && (strcmp(h->h_name, (char *)hih->h_hintvalue) == 0)) { before = hi; } } if (before != NULL) { TAILQ_INSERT_AFTER(head, before, new, hi_entry); return (0); } hook_insert_plain(head, new); break; case HH_FIRST : hi = TAILQ_FIRST(head); if ((hi != NULL) && (hi->hi_hook.h_hint == HH_FIRST)) return (EBUSY); TAILQ_INSERT_HEAD(head, new, hi_entry); break; case HH_LAST : hi = TAILQ_LAST(head, hook_int_head); if ((hi != NULL) && (hi->hi_hook.h_hint == HH_LAST)) return (EBUSY); TAILQ_INSERT_TAIL(head, new, hi_entry); break; case HH_BEFORE : hi = hook_find_byname(head, (char *)new->hi_hook.h_hintvalue); if (hi == NULL) return (hook_insert_afterbefore(head, new)); if (hi->hi_hook.h_hint == HH_FIRST) return (EBUSY); TAILQ_INSERT_BEFORE(hi, new, hi_entry); break; case HH_AFTER : hi = hook_find_byname(head, (char *)new->hi_hook.h_hintvalue); if (hi == NULL) return (hook_insert_afterbefore(head, new)); if (hi->hi_hook.h_hint == HH_LAST) return (EBUSY); TAILQ_INSERT_AFTER(head, hi, new, hi_entry); break; default : return (EINVAL); } return (0); } /* * Function: hook_insert_plain * Returns: int- 0 = success, else = failure * Parameters: head(I) - pointer to hook list to insert hook onto * new(I) - pointer to hook to be inserted * * Insert a hook such that it respects the wishes of those that want to * be last. If there are none wanting to be last then add the new hook * to the tail of the list - this means we keep any wanting to be first * happy without having to search for HH_FIRST. */ static void hook_insert_plain(hook_int_head_t *head, hook_int_t *new) { hook_int_t *hi; hi = TAILQ_FIRST(head); if (hi != NULL) { if (hi->hi_hook.h_hint == HH_LAST) { TAILQ_INSERT_BEFORE(hi, new, hi_entry); } else { TAILQ_INSERT_TAIL(head, new, hi_entry); } } else { TAILQ_INSERT_TAIL(head, new, hi_entry); } } /* * Function: hook_insert_afterbefore * Returns: int- 0 = success, else = failure * Parameters: head(I) - pointer to hook list to insert hook onto * new(I) - pointer to hook to be inserted * * Simple insertion of a hook specifying a HH_BEFORE or HH_AFTER was not * possible, so now we need to be more careful. The first pass is to go * through the list and look for any other hooks that also specify the * same hint name as the new one. The object of this exercise is to make * sure that hooks with HH_BEFORE always appear on the list before those * with HH_AFTER so that when said hook arrives, it can be placed in the * middle of the BEFOREs and AFTERs. If this condition does not arise, * just use hook_insert_plain() to try and insert the hook somewhere that * is innocuous to existing efforts. */ static int hook_insert_afterbefore(hook_int_head_t *head, hook_int_t *new) { hook_int_t *hi; hook_t *nh; hook_t *h; nh = &new->hi_hook; ASSERT(new->hi_hook.h_hint != HH_NONE); ASSERT(new->hi_hook.h_hint != HH_LAST); ASSERT(new->hi_hook.h_hint != HH_FIRST); /* * First, look through the list to see if there are any other * before's or after's that have a matching hint name. */ TAILQ_FOREACH(hi, head, hi_entry) { h = &hi->hi_hook; switch (h->h_hint) { case HH_FIRST : case HH_LAST : case HH_NONE : break; case HH_BEFORE : if ((nh->h_hint == HH_BEFORE) && (strcmp((char *)h->h_hintvalue, (char *)nh->h_hintvalue) == 0)) { TAILQ_INSERT_AFTER(head, hi, new, hi_entry); return (0); } if ((nh->h_hint == HH_AFTER) && (strcmp((char *)h->h_hintvalue, (char *)nh->h_hintvalue) == 0)) { TAILQ_INSERT_BEFORE(hi, new, hi_entry); return (0); } break; case HH_AFTER : if ((nh->h_hint == HH_AFTER) && (strcmp((char *)h->h_hintvalue, (char *)nh->h_hintvalue) == 0)) { TAILQ_INSERT_AFTER(head, hi, new, hi_entry); return (0); } if ((nh->h_hint == HH_BEFORE) && (strcmp((char *)h->h_hintvalue, (char *)nh->h_hintvalue) == 0)) { TAILQ_INSERT_BEFORE(hi, new, hi_entry); return (0); } break; } } hook_insert_plain(head, new); return (0); } /* * Function: hook_unregister * Returns: int - 0 = Succ, Else = Fail * Parameters: hfi(I) - internal family pointer * event(I) - event name string * h(I) - hook pointer * * Remove hook from hook list on specific family, event */ int hook_unregister(hook_family_int_t *hfi, char *event, hook_t *h) { hook_event_int_t *hei; hook_int_t *hi; boolean_t free_event; ASSERT(hfi != NULL); ASSERT(h != NULL); CVW_ENTER_WRITE(&hfi->hfi_lock); hei = hook_event_find(hfi, event); if (hei == NULL) { CVW_EXIT_WRITE(&hfi->hfi_lock); return (ENXIO); } /* Hold write lock for event */ CVW_ENTER_WRITE(&hei->hei_lock); hi = hook_find(hei, h); if (hi == NULL) { CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_WRITE(&hfi->hfi_lock); return (ENXIO); } if (hook_wait_setflag(&hei->hei_waiter, FWF_WAIT_MASK, FWF_DEL_WANTED, FWF_DEL_ACTIVE) == -1) { CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_WRITE(&hfi->hfi_lock); return (ENOENT); } /* Remove from hook list */ TAILQ_REMOVE(&hei->hei_head, hi, hi_entry); free_event = B_FALSE; if (TAILQ_EMPTY(&hei->hei_head)) { hei->hei_event->he_interested = B_FALSE; /* * If the delete pending flag has been set and there are * no notifiers on the event (and we've removed the last * hook) then we need to free this event after we're done. */ if (hei->hei_condemned && TAILQ_EMPTY(&hei->hei_nhead)) free_event = B_TRUE; } hei->hei_kstats.hooks_removed.value.ui64++; CVW_EXIT_WRITE(&hei->hei_lock); CVW_EXIT_WRITE(&hfi->hfi_lock); /* * While the FWF_DEL_ACTIVE flag is set, the hook_event_int_t * will not be free'd and thus the hook_family_int_t wil not * be free'd either. */ hook_event_notify_run(hei, hfi, event, h->h_name, HN_UNREGISTER); hook_wait_unsetflag(&hei->hei_waiter, FWF_DEL_ACTIVE); hook_int_free(hi, hfi->hfi_stack->hks_netstackid); if (free_event) hook_event_free(hei, hfi); return (0); } /* * Function: hook_find_byname * Returns: internal hook pointer - NULL = Not match * Parameters: hei(I) - internal event pointer * name(I)- hook name * * Search an event's list of hooks to see if there is a hook present that * has a matching name to the one being looked for. */ static hook_int_t * hook_find_byname(hook_int_head_t *head, char *name) { hook_int_t *hi; TAILQ_FOREACH(hi, head, hi_entry) { if (strcmp(hi->hi_hook.h_name, name) == 0) return (hi); } return (NULL); } /* * Function: hook_find * Returns: internal hook pointer - NULL = Not match * Parameters: hei(I) - internal event pointer * h(I) - hook pointer * * Search an event's list of hooks to see if there is already one that * matches the hook being passed in. Currently the only criteria for a * successful search here is for the names to be the same. */ static hook_int_t * hook_find(hook_event_int_t *hei, hook_t *h) { ASSERT(hei != NULL); ASSERT(h != NULL); return (hook_find_byname(&hei->hei_head, h->h_name)); } /* * Function: hook_copy * Returns: internal hook pointer - NULL = Failed * Parameters: src(I) - hook pointer * * Allocate internal hook block and duplicate incoming hook. * No locks should be held across this function as it may sleep. * Because hook_copy() is responsible for the creation of the internal * hook structure that is used here, it takes on population the structure * with the kstat information. Note that while the kstat bits are * seeded here, their installation of the kstats is handled elsewhere. */ static hook_int_t * hook_copy(hook_t *src) { hook_int_t *new; hook_t *dst; int len; ASSERT(src != NULL); ASSERT(src->h_name != NULL); new = (hook_int_t *)kmem_zalloc(sizeof (*new), KM_SLEEP); /* Copy body */ dst = &new->hi_hook; *dst = *src; /* Copy name */ len = strlen(src->h_name); dst->h_name = (char *)kmem_alloc(len + 1, KM_SLEEP); (void) strcpy(dst->h_name, src->h_name); /* * This is initialised in this manner to make it safer to use the * same pointer in the kstats field. */ dst->h_hintvalue = (uintptr_t)""; if (dst->h_hint == HH_BEFORE || dst->h_hint == HH_AFTER) { len = strlen((char *)src->h_hintvalue); if (len > 0) { dst->h_hintvalue = (uintptr_t)kmem_alloc(len + 1, KM_SLEEP); (void) strcpy((char *)dst->h_hintvalue, (char *)src->h_hintvalue); } } return (new); } /* * Function: hook_init_kstats * Returns: None * Parameters: hfi(I) - pointer to the family that owns the event. * hei(I) - pointer to the event that owns this hook * hi(I) - pointer to the hook for which we create kstats for * * Each hook that is registered with this framework has its own kstats * set up so that we can provide an easy way in which to observe the * look of hooks (using the kstat command.) The position is set to 0 * here but is recalculated after we know the insertion has been a * success. */ static void hook_init_kstats(hook_family_int_t *hfi, hook_event_int_t *hei, hook_int_t *hi) { hook_hook_kstat_t template = { { "version", KSTAT_DATA_INT32 }, { "flags", KSTAT_DATA_UINT32 }, { "hint", KSTAT_DATA_INT32 }, { "hint_value", KSTAT_DATA_UINT64 }, { "position", KSTAT_DATA_INT32 }, { "hook_hits", KSTAT_DATA_UINT64 } }; hook_stack_t *hks; size_t kslen; int position; hook_int_t *h; kslen = strlen(hfi->hfi_family.hf_name) + strlen(hei->hei_event->he_name) + 2; hi->hi_ksname = (char *)kmem_zalloc(kslen, KM_SLEEP); (void) snprintf(hi->hi_ksname, kslen, "%s/%s", hfi->hfi_family.hf_name, hei->hei_event->he_name); hks = hfi->hfi_stack; hi->hi_kstatp = kstat_create_netstack(hi->hi_ksname, 0, hi->hi_hook.h_name, "hook", KSTAT_TYPE_NAMED, sizeof (hi->hi_kstats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL, hks->hks_netstackid); /* Initialise the kstats for the structure */ bcopy(&template, &hi->hi_kstats, sizeof (template)); hi->hi_kstats.hook_version.value.i32 = hi->hi_hook.h_version; hi->hi_kstats.hook_flags.value.ui32 = hi->hi_hook.h_flags; hi->hi_kstats.hook_hint.value.i32 = hi->hi_hook.h_hint; hi->hi_kstats.hook_position.value.i32 = 0; hi->hi_kstats.hook_hits.value.ui64 = 0; switch (hi->hi_hook.h_hint) { case HH_BEFORE : case HH_AFTER : hi->hi_kstats.hook_hintvalue.data_type = KSTAT_DATA_STRING; hi->hi_kstats.hook_hintvalue.value.ui64 = hi->hi_hook.h_hintvalue; break; default : break; } if (hi->hi_kstatp != NULL) { hi->hi_kstatp->ks_data = (void *)&hi->hi_kstats; hi->hi_kstatp->ks_private = (void *)(uintptr_t)hks->hks_netstackid; kstat_install(hi->hi_kstatp); } position = 1; TAILQ_FOREACH(h, &hei->hei_head, hi_entry) { h->hi_kstats.hook_position.value.ui32 = position++; } } /* * Function: hook_int_free * Returns: None * Parameters: hi(I) - internal hook pointer * * Free alloc memory for hook */ static void hook_int_free(hook_int_t *hi, netstackid_t stackid) { int len; ASSERT(hi != NULL); /* Free name space */ if (hi->hi_hook.h_name != NULL) { kmem_free(hi->hi_hook.h_name, strlen(hi->hi_hook.h_name) + 1); } if (hi->hi_ksname != NULL) { kmem_free(hi->hi_ksname, strlen(hi->hi_ksname) + 1); } /* Free the name used with the before/after hints. */ switch (hi->hi_hook.h_hint) { case HH_BEFORE : case HH_AFTER : len = strlen((char *)hi->hi_hook.h_hintvalue); if (len > 0) kmem_free((void *)hi->hi_hook.h_hintvalue, len + 1); break; default : break; } if (hi->hi_kstatp != NULL) kstat_delete_netstack(hi->hi_kstatp, stackid); /* Free container */ kmem_free(hi, sizeof (*hi)); } /* * Function: hook_alloc * Returns: hook_t * - pointer to new hook structure * Parameters: version(I) - version number of the API when compiled * * This function serves as the interface for consumers to obtain a hook_t * structure. At this point in time, there is only a single "version" of * it, leading to a straight forward function. In a perfect world the * h_vesion would be a protected data structure member, but C isn't that * advanced... */ hook_t * hook_alloc(const int h_version) { hook_t *h; h = kmem_zalloc(sizeof (hook_t), KM_SLEEP); h->h_version = h_version; return (h); } /* * Function: hook_free * Returns: None * Parameters: h(I) - external hook pointer * * This function only free's memory allocated with hook_alloc(), so that if * (for example) kernel memory was allocated for h_name, this needs to be * free'd before calling hook_free(). */ void hook_free(hook_t *h) { kmem_free(h, sizeof (*h)); } /* * Function: hook_notify_register * Returns: 0 = success, else failure * Parameters: lock(I) - netstack identifier * head(I) - top of the list of callbacks * callback(I) - function to be called * arg(I) - arg to pass back to the function * * This function implements the modification of the list of callbacks * that are registered when someone wants to be advised of a change * that has happened. */ static int hook_notify_register(cvwaitlock_t *lock, hook_notify_head_t *head, hook_notify_fn_t callback, void *arg) { hook_notify_t *hn; CVW_ENTER_WRITE(lock); TAILQ_FOREACH(hn, head, hn_entry) { if (hn->hn_func == callback) { CVW_EXIT_WRITE(lock); return (EEXIST); } } hn = (hook_notify_t *)kmem_alloc(sizeof (*hn), KM_SLEEP); hn->hn_func = callback; hn->hn_arg = arg; TAILQ_INSERT_TAIL(head, hn, hn_entry); CVW_EXIT_WRITE(lock); return (0); } /* * Function: hook_stack_notify_register * Returns: 0 = success, else failure * Parameters: stackid(I) - netstack identifier * callback(I) - function to be called * */ static int hook_notify_unregister(cvwaitlock_t *lock, hook_notify_head_t *head, hook_notify_fn_t callback) { hook_notify_t *hn; CVW_ENTER_WRITE(lock); TAILQ_FOREACH(hn, head, hn_entry) { if (hn->hn_func == callback) break; } if (hn == NULL) { CVW_EXIT_WRITE(lock); return (ESRCH); } TAILQ_REMOVE(head, hn, hn_entry); CVW_EXIT_WRITE(lock); kmem_free(hn, sizeof (*hn)); return (0); } /* * Function: hook_notify_run * Returns: None * Parameters: head(I) - top of the list of callbacks * family(I) - name of the hook family that owns the event * event(I) - name of the event being changed * name(I) - name of the object causing change * cmd(I) - either HN_UNREGISTER or HN_REGISTER * * This function walks through the list of registered callbacks and * executes each one, passing back the arg supplied when registered * and the name of the family (that owns the event), event (the thing * to which we're making a change) and finally a name that describes * what is being added or removed, as indicated by cmd. * * This function does not acquire or release any lock as it is required * that code calling it do so before hand. The use of hook_notify_head_t * is protected by the use of flagwait_t in the structures that own this * list and with the use of the FWF_ADD/DEL_ACTIVE flags. */ static void hook_notify_run(hook_notify_head_t *head, char *family, char *event, char *name, hook_notify_cmd_t cmd) { hook_notify_t *hn; TAILQ_FOREACH(hn, head, hn_entry) { (*hn->hn_func)(cmd, hn->hn_arg, family, event, name); } }