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Resolve the confusion between the head_list and the hook list.

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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:
Andre Oppermann 2013-08-24 11:17:25 +00:00
parent bacda5aaa9
commit 8da0139975
2 changed files with 48 additions and 35 deletions
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54
sys/net/pfil.c
View File

@ -52,9 +52,9 @@ static struct mtx pfil_global_lock;
MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
MTX_DEF);
static struct packet_filter_hook *pfil_hook_get(int, struct pfil_head *);
static int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
static int pfil_list_remove(pfil_list_t *, pfil_func_t, void *);
static struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *);
static int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int);
static int pfil_chain_remove(pfil_chain_t *, pfil_func_t, void *);
LIST_HEAD(pfilheadhead, pfil_head);
VNET_DEFINE(struct pfilheadhead, pfil_head_list);
@ -63,7 +63,7 @@ VNET_DEFINE(struct rmlock, pfil_lock);
#define V_pfil_lock VNET(pfil_lock)
/*
* pfil_run_hooks() runs the specified packet filter hooks.
* pfil_run_hooks() runs the specified packet filter hook chain.
*/
int
pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
@ -76,8 +76,8 @@ pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
PFIL_RLOCK(ph, &rmpt);
KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
pfh = TAILQ_NEXT(pfh, pfil_link)) {
for (pfh = pfil_chain_get(dir, ph); pfh != NULL;
pfh = TAILQ_NEXT(pfh, pfil_chain)) {
if (pfh->pfil_func != NULL) {
rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
inp);
@ -91,7 +91,7 @@ pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
}
static struct packet_filter_hook *
pfil_hook_get(int dir, struct pfil_head *ph)
pfil_chain_get(int dir, struct pfil_head *ph)
{
if (dir == PFIL_IN)
@ -163,6 +163,7 @@ pfil_wowned(struct pfil_head *ph)
return (PFIL_WOWNED(ph));
}
/*
* pfil_head_register() registers a pfil_head with the packet filter hook
* mechanism.
@ -202,9 +203,9 @@ pfil_head_unregister(struct pfil_head *ph)
PFIL_LIST_LOCK();
LIST_REMOVE(ph, ph_list);
PFIL_LIST_UNLOCK();
TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext)
free(pfh, M_IFADDR);
TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, pfnext)
free(pfh, M_IFADDR);
PFIL_LOCK_DESTROY(ph);
return (0);
@ -261,7 +262,7 @@ pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
if (flags & PFIL_IN) {
pfh1->pfil_func = func;
pfh1->pfil_arg = arg;
err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
if (err)
goto locked_error;
ph->ph_nhooks++;
@ -269,10 +270,10 @@ pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
if (flags & PFIL_OUT) {
pfh2->pfil_func = func;
pfh2->pfil_arg = arg;
err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
if (err) {
if (flags & PFIL_IN)
pfil_list_remove(&ph->ph_in, func, arg);
pfil_chain_remove(&ph->ph_in, func, arg);
goto locked_error;
}
ph->ph_nhooks++;
@ -291,7 +292,7 @@ pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
/*
* pfil_remove_hook removes a specific function from the packet filter hook
* list.
* chain.
*/
int
pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
@ -300,12 +301,12 @@ pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
PFIL_WLOCK(ph);
if (flags & PFIL_IN) {
err = pfil_list_remove(&ph->ph_in, func, arg);
err = pfil_chain_remove(&ph->ph_in, func, arg);
if (err == 0)
ph->ph_nhooks--;
}
if ((err == 0) && (flags & PFIL_OUT)) {
err = pfil_list_remove(&ph->ph_out, func, arg);
err = pfil_chain_remove(&ph->ph_out, func, arg);
if (err == 0)
ph->ph_nhooks--;
}
@ -313,15 +314,18 @@ pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
return (err);
}
/*
* Internal: Add a new pfil hook into a hook chain.
*/
static int
pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
pfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags)
{
struct packet_filter_hook *pfh;
/*
* First make sure the hook is not already there.
*/
TAILQ_FOREACH(pfh, list, pfil_link)
TAILQ_FOREACH(pfh, chain, pfil_chain)
if (pfh->pfil_func == pfh1->pfil_func &&
pfh->pfil_arg == pfh1->pfil_arg)
return (EEXIST);
@ -331,24 +335,23 @@ pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
* the same path is followed in or out of the kernel.
*/
if (flags & PFIL_IN)
TAILQ_INSERT_HEAD(list, pfh1, pfil_link);
TAILQ_INSERT_HEAD(chain, pfh1, pfil_chain);
else
TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain);
return (0);
}
/*
* pfil_list_remove is an internal function that takes a function off the
* specified list.
* Internal: Remove a pfil hook from a hook chain.
*/
static int
pfil_list_remove(pfil_list_t *list, pfil_func_t func, void *arg)
pfil_chain_remove(pfil_chain_t *chain, pfil_func_t func, void *arg)
{
struct packet_filter_hook *pfh;
TAILQ_FOREACH(pfh, list, pfil_link)
TAILQ_FOREACH(pfh, chain, pfil_chain)
if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
TAILQ_REMOVE(list, pfh, pfil_link);
TAILQ_REMOVE(chain, pfh, pfil_chain);
free(pfh, M_IFADDR);
return (0);
}
@ -375,7 +378,8 @@ static int
vnet_pfil_uninit(const void *unused)
{
/* XXX should panic if list is not empty */
KASSERT(LIST_EMPTY(&V_pfil_head_list),
("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list));
PFIL_LOCK_DESTROY_REAL(&V_pfil_lock);
return (0);
}

29
sys/net/pfil.h
View File

@ -48,10 +48,11 @@ typedef int (*pfil_func_t)(void *, struct mbuf **, struct ifnet *, int,
/*
* The packet filter hooks are designed for anything to call them to
* possibly intercept the packet.
* possibly intercept the packet. Multiple filter hooks are chained
* together and after each other in the specified order.
*/
struct packet_filter_hook {
TAILQ_ENTRY(packet_filter_hook) pfil_link;
TAILQ_ENTRY(packet_filter_hook) pfil_chain;
pfil_func_t pfil_func;
void *pfil_arg;
};
@ -61,16 +62,20 @@ struct packet_filter_hook {
#define PFIL_WAITOK 0x00000004
#define PFIL_ALL (PFIL_IN|PFIL_OUT)
typedef TAILQ_HEAD(pfil_list, packet_filter_hook) pfil_list_t;
typedef TAILQ_HEAD(pfil_chain, packet_filter_hook) pfil_chain_t;
#define PFIL_TYPE_AF 1 /* key is AF_* type */
#define PFIL_TYPE_IFNET 2 /* key is ifnet pointer */
#define PFIL_FLAG_PRIVATE_LOCK 0x01 /* Personal lock instead of global */
/*
* A pfil head is created by each protocol or packet intercept point.
* For packet is then run through the hook chain for inspection.
*/
struct pfil_head {
pfil_list_t ph_in;
pfil_list_t ph_out;
pfil_chain_t ph_in;
pfil_chain_t ph_out;
int ph_type;
int ph_nhooks;
#if defined( __linux__ ) || defined( _WIN32 )
@ -89,11 +94,20 @@ struct pfil_head {
LIST_ENTRY(pfil_head) ph_list;
};
/* Public functions for pfil hook management by packet filters. */
struct pfil_head *pfil_head_get(int, u_long);
int pfil_add_hook(pfil_func_t, void *, int, struct pfil_head *);
int pfil_remove_hook(pfil_func_t, void *, int, struct pfil_head *);
/* Public functions to run the packet inspection by protocols. */
int pfil_run_hooks(struct pfil_head *, struct mbuf **, struct ifnet *,
int, struct inpcb *inp);
/* Public functions for pfil head management by protocols. */
int pfil_head_register(struct pfil_head *);
int pfil_head_unregister(struct pfil_head *);
/* Internal pfil locking functions. */
struct rm_priotracker; /* Do not require including rmlock header */
int pfil_try_rlock(struct pfil_head *, struct rm_priotracker *);
void pfil_rlock(struct pfil_head *, struct rm_priotracker *);
@ -102,11 +116,6 @@ void pfil_wlock(struct pfil_head *);
void pfil_wunlock(struct pfil_head *);
int pfil_wowned(struct pfil_head *ph);
int pfil_head_register(struct pfil_head *);
int pfil_head_unregister(struct pfil_head *);
struct pfil_head *pfil_head_get(int, u_long);
#define PFIL_HOOKED(p) ((p)->ph_nhooks > 0)
#define PFIL_LOCK_INIT_REAL(l, t) \
rm_init_flags(l, "PFil " t " rmlock", RM_RECURSE)