Resolve the confusion between the head_list and the hook list.
The linked list of pfil hooks is changed to "chain" and this term is applied consistently. The head_list remains with "list" term. Add KASSERT to vnet_pfil_uninit(). Update and extend comments. Reviewed by: eri (previous version)
This commit is contained in:
parent
bacda5aaa9
commit
8da0139975
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=254773
@ -52,9 +52,9 @@ static struct mtx pfil_global_lock;
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MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
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MTX_DEF);
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static struct packet_filter_hook *pfil_hook_get(int, struct pfil_head *);
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static int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
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static int pfil_list_remove(pfil_list_t *, pfil_func_t, void *);
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static struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *);
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static int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int);
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static int pfil_chain_remove(pfil_chain_t *, pfil_func_t, void *);
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LIST_HEAD(pfilheadhead, pfil_head);
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VNET_DEFINE(struct pfilheadhead, pfil_head_list);
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@ -63,7 +63,7 @@ VNET_DEFINE(struct rmlock, pfil_lock);
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#define V_pfil_lock VNET(pfil_lock)
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/*
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* pfil_run_hooks() runs the specified packet filter hooks.
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* pfil_run_hooks() runs the specified packet filter hook chain.
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*/
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int
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pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
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@ -76,8 +76,8 @@ pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
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PFIL_RLOCK(ph, &rmpt);
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KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
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for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
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pfh = TAILQ_NEXT(pfh, pfil_link)) {
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for (pfh = pfil_chain_get(dir, ph); pfh != NULL;
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pfh = TAILQ_NEXT(pfh, pfil_chain)) {
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if (pfh->pfil_func != NULL) {
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rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
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inp);
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@ -91,7 +91,7 @@ pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
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}
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static struct packet_filter_hook *
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pfil_hook_get(int dir, struct pfil_head *ph)
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pfil_chain_get(int dir, struct pfil_head *ph)
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{
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if (dir == PFIL_IN)
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@ -163,6 +163,7 @@ pfil_wowned(struct pfil_head *ph)
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return (PFIL_WOWNED(ph));
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}
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/*
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* pfil_head_register() registers a pfil_head with the packet filter hook
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* mechanism.
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@ -202,9 +203,9 @@ pfil_head_unregister(struct pfil_head *ph)
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PFIL_LIST_LOCK();
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LIST_REMOVE(ph, ph_list);
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PFIL_LIST_UNLOCK();
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TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
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TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext)
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free(pfh, M_IFADDR);
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TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
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TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, pfnext)
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free(pfh, M_IFADDR);
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PFIL_LOCK_DESTROY(ph);
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return (0);
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@ -261,7 +262,7 @@ pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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if (flags & PFIL_IN) {
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pfh1->pfil_func = func;
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pfh1->pfil_arg = arg;
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err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
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err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
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if (err)
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goto locked_error;
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ph->ph_nhooks++;
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@ -269,10 +270,10 @@ pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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if (flags & PFIL_OUT) {
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pfh2->pfil_func = func;
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pfh2->pfil_arg = arg;
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err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
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err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
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if (err) {
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if (flags & PFIL_IN)
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pfil_list_remove(&ph->ph_in, func, arg);
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pfil_chain_remove(&ph->ph_in, func, arg);
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goto locked_error;
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}
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ph->ph_nhooks++;
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@ -291,7 +292,7 @@ pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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/*
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* pfil_remove_hook removes a specific function from the packet filter hook
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* list.
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* chain.
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*/
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int
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pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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@ -300,12 +301,12 @@ pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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PFIL_WLOCK(ph);
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if (flags & PFIL_IN) {
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err = pfil_list_remove(&ph->ph_in, func, arg);
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err = pfil_chain_remove(&ph->ph_in, func, arg);
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if (err == 0)
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ph->ph_nhooks--;
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}
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if ((err == 0) && (flags & PFIL_OUT)) {
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err = pfil_list_remove(&ph->ph_out, func, arg);
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err = pfil_chain_remove(&ph->ph_out, func, arg);
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if (err == 0)
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ph->ph_nhooks--;
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}
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@ -313,15 +314,18 @@ pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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return (err);
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}
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/*
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* Internal: Add a new pfil hook into a hook chain.
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*/
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static int
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pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
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pfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags)
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{
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struct packet_filter_hook *pfh;
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/*
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* First make sure the hook is not already there.
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*/
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TAILQ_FOREACH(pfh, list, pfil_link)
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TAILQ_FOREACH(pfh, chain, pfil_chain)
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if (pfh->pfil_func == pfh1->pfil_func &&
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pfh->pfil_arg == pfh1->pfil_arg)
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return (EEXIST);
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@ -331,24 +335,23 @@ pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
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* the same path is followed in or out of the kernel.
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*/
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if (flags & PFIL_IN)
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TAILQ_INSERT_HEAD(list, pfh1, pfil_link);
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TAILQ_INSERT_HEAD(chain, pfh1, pfil_chain);
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else
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TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
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TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain);
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return (0);
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}
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/*
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* pfil_list_remove is an internal function that takes a function off the
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* specified list.
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* Internal: Remove a pfil hook from a hook chain.
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*/
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static int
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pfil_list_remove(pfil_list_t *list, pfil_func_t func, void *arg)
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pfil_chain_remove(pfil_chain_t *chain, pfil_func_t func, void *arg)
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{
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struct packet_filter_hook *pfh;
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TAILQ_FOREACH(pfh, list, pfil_link)
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TAILQ_FOREACH(pfh, chain, pfil_chain)
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if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
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TAILQ_REMOVE(list, pfh, pfil_link);
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TAILQ_REMOVE(chain, pfh, pfil_chain);
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free(pfh, M_IFADDR);
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return (0);
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}
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@ -375,7 +378,8 @@ static int
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vnet_pfil_uninit(const void *unused)
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{
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/* XXX should panic if list is not empty */
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KASSERT(LIST_EMPTY(&V_pfil_head_list),
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("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list));
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PFIL_LOCK_DESTROY_REAL(&V_pfil_lock);
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return (0);
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}
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@ -48,10 +48,11 @@ typedef int (*pfil_func_t)(void *, struct mbuf **, struct ifnet *, int,
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/*
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* The packet filter hooks are designed for anything to call them to
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* possibly intercept the packet.
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* possibly intercept the packet. Multiple filter hooks are chained
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* together and after each other in the specified order.
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*/
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struct packet_filter_hook {
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TAILQ_ENTRY(packet_filter_hook) pfil_link;
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TAILQ_ENTRY(packet_filter_hook) pfil_chain;
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pfil_func_t pfil_func;
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void *pfil_arg;
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};
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@ -61,16 +62,20 @@ struct packet_filter_hook {
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#define PFIL_WAITOK 0x00000004
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#define PFIL_ALL (PFIL_IN|PFIL_OUT)
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typedef TAILQ_HEAD(pfil_list, packet_filter_hook) pfil_list_t;
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typedef TAILQ_HEAD(pfil_chain, packet_filter_hook) pfil_chain_t;
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#define PFIL_TYPE_AF 1 /* key is AF_* type */
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#define PFIL_TYPE_IFNET 2 /* key is ifnet pointer */
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#define PFIL_FLAG_PRIVATE_LOCK 0x01 /* Personal lock instead of global */
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/*
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* A pfil head is created by each protocol or packet intercept point.
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* For packet is then run through the hook chain for inspection.
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*/
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struct pfil_head {
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pfil_list_t ph_in;
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pfil_list_t ph_out;
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pfil_chain_t ph_in;
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pfil_chain_t ph_out;
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int ph_type;
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int ph_nhooks;
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#if defined( __linux__ ) || defined( _WIN32 )
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@ -89,11 +94,20 @@ struct pfil_head {
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LIST_ENTRY(pfil_head) ph_list;
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};
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/* Public functions for pfil hook management by packet filters. */
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struct pfil_head *pfil_head_get(int, u_long);
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int pfil_add_hook(pfil_func_t, void *, int, struct pfil_head *);
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int pfil_remove_hook(pfil_func_t, void *, int, struct pfil_head *);
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/* Public functions to run the packet inspection by protocols. */
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int pfil_run_hooks(struct pfil_head *, struct mbuf **, struct ifnet *,
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int, struct inpcb *inp);
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/* Public functions for pfil head management by protocols. */
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int pfil_head_register(struct pfil_head *);
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int pfil_head_unregister(struct pfil_head *);
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/* Internal pfil locking functions. */
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struct rm_priotracker; /* Do not require including rmlock header */
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int pfil_try_rlock(struct pfil_head *, struct rm_priotracker *);
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void pfil_rlock(struct pfil_head *, struct rm_priotracker *);
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@ -102,11 +116,6 @@ void pfil_wlock(struct pfil_head *);
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void pfil_wunlock(struct pfil_head *);
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int pfil_wowned(struct pfil_head *ph);
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int pfil_head_register(struct pfil_head *);
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int pfil_head_unregister(struct pfil_head *);
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struct pfil_head *pfil_head_get(int, u_long);
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#define PFIL_HOOKED(p) ((p)->ph_nhooks > 0)
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#define PFIL_LOCK_INIT_REAL(l, t) \
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rm_init_flags(l, "PFil " t " rmlock", RM_RECURSE)
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