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author | csjp <csjp@FreeBSD.org> | 2006-02-02 03:13:16 +0000 |
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committer | csjp <csjp@FreeBSD.org> | 2006-02-02 03:13:16 +0000 |
commit | 31292a14b63b17ba5db98a0848f9166080240c14 (patch) | |
tree | 70762151820deceeeabd2497892bd015c4607785 /sys/net/pfil.c | |
parent | ee6a12ceacf369efe24e49fa5ba813f41b43bd89 (diff) | |
download | FreeBSD-src-31292a14b63b17ba5db98a0848f9166080240c14.zip FreeBSD-src-31292a14b63b17ba5db98a0848f9166080240c14.tar.gz |
Somewhat re-factor the read/write locking mechanism associated with the packet
filtering mechanisms to use the new rwlock(9) locking API:
- Drop the variables stored in the phil_head structure which were specific to
conditions and the home rolled read/write locking mechanism.
- Drop some includes which were used for condition variables
- Drop the inline functions, and convert them to macros. Also, move these
macros into pfil.h
- Move pfil list locking macros intp phil.h as well
- Rename ph_busy_count to ph_nhooks. This variable will represent the number
of IN/OUT hooks registered with the pfil head structure
- Define PFIL_HOOKED macro which evaluates to true if there are any
hooks to be ran by pfil_run_hooks
- In the IP/IP6 stacks, change the ph_busy_count comparison to use the new
PFIL_HOOKED macro.
- Drop optimization in pfil_run_hooks which checks to see if there are any
hooks to be ran, and returns if not. This check is already performed by the
IP stacks when they call:
if (!PFIL_HOOKED(ph))
goto skip_hooks;
- Drop in assertion which makes sure that the number of hooks never drops
below 0 for good measure. This in theory should never happen, and if it
does than there are problems somewhere
- Drop special logic around PFIL_WAITOK because rw_wlock(9) does not sleep
- Drop variables which support home rolled read/write locking mechanism from
the IPFW firewall chain structure.
- Swap out the read/write firewall chain lock internal to use the rwlock(9)
API instead of our home rolled version
- Convert the inlined functions to macros
Reviewed by: mlaier, andre, glebius
Thanks to: jhb for the new locking API
Diffstat (limited to 'sys/net/pfil.c')
-rw-r--r-- | sys/net/pfil.c | 122 |
1 files changed, 22 insertions, 100 deletions
diff --git a/sys/net/pfil.c b/sys/net/pfil.c index 35ac338..78b87f3 100644 --- a/sys/net/pfil.c +++ b/sys/net/pfil.c @@ -32,7 +32,9 @@ #include <sys/param.h> #include <sys/kernel.h> #include <sys/errno.h> +#include <sys/lock.h> #include <sys/malloc.h> +#include <sys/rwlock.h> #include <sys/socket.h> #include <sys/socketvar.h> #include <sys/systm.h> @@ -57,57 +59,6 @@ static int pfil_list_remove(pfil_list_t *, LIST_HEAD(, pfil_head) pfil_head_list = LIST_HEAD_INITIALIZER(&pfil_head_list); -static __inline void -PFIL_RLOCK(struct pfil_head *ph) -{ - mtx_lock(&ph->ph_mtx); - ph->ph_busy_count++; - mtx_unlock(&ph->ph_mtx); -} - -static __inline void -PFIL_RUNLOCK(struct pfil_head *ph) -{ - mtx_lock(&ph->ph_mtx); - ph->ph_busy_count--; - if (ph->ph_busy_count == 0 && ph->ph_want_write) - cv_signal(&ph->ph_cv); - mtx_unlock(&ph->ph_mtx); -} - -static __inline void -PFIL_WLOCK(struct pfil_head *ph) -{ - mtx_lock(&ph->ph_mtx); - ph->ph_want_write = 1; - while (ph->ph_busy_count > 0) - cv_wait(&ph->ph_cv, &ph->ph_mtx); -} - -static __inline int -PFIL_TRY_WLOCK(struct pfil_head *ph) -{ - mtx_lock(&ph->ph_mtx); - ph->ph_want_write = 1; - if (ph->ph_busy_count > 0) { - ph->ph_want_write = 0; - mtx_unlock(&ph->ph_mtx); - return EBUSY; - } - return 0; -} - -static __inline void -PFIL_WUNLOCK(struct pfil_head *ph) -{ - ph->ph_want_write = 0; - cv_signal(&ph->ph_cv); - mtx_unlock(&ph->ph_mtx); -} - -#define PFIL_LIST_LOCK() mtx_lock(&pfil_global_lock) -#define PFIL_LIST_UNLOCK() mtx_unlock(&pfil_global_lock) - /* * pfil_run_hooks() runs the specified packet filter hooks. */ @@ -119,20 +70,8 @@ pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp, struct mbuf *m = *mp; int rv = 0; - if (ph->ph_busy_count == -1) - return (0); - /* - * Prevent packet filtering from starving the modification of - * the packet filters. We would prefer a reader/writer locking - * mechanism with guaranteed ordering, though. - */ - if (ph->ph_want_write) { - m_freem(*mp); - *mp = NULL; - return (ENOBUFS); - } - PFIL_RLOCK(ph); + 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)) { if (pfh->pfil_func != NULL) { @@ -165,16 +104,9 @@ pfil_head_register(struct pfil_head *ph) } PFIL_LIST_UNLOCK(); - if (mtx_initialized(&ph->ph_mtx)) { /* should not happen */ - KASSERT((0), ("%s: allready initialized!", __func__)); - return EBUSY; - } else { - ph->ph_busy_count = -1; - ph->ph_want_write = 1; - mtx_init(&ph->ph_mtx, "pfil_head_mtx", NULL, MTX_DEF); - cv_init(&ph->ph_cv, "pfil_head_cv"); - mtx_lock(&ph->ph_mtx); /* XXX: race? */ - } + rw_init(&ph->ph_mtx, "PFil hook read/write mutex"); + PFIL_WLOCK(ph); + ph->ph_nhooks = 0; TAILQ_INIT(&ph->ph_in); TAILQ_INIT(&ph->ph_out); @@ -182,9 +114,9 @@ pfil_head_register(struct pfil_head *ph) PFIL_LIST_LOCK(); LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list); PFIL_LIST_UNLOCK(); - + PFIL_WUNLOCK(ph); - + return (0); } @@ -205,14 +137,13 @@ pfil_head_unregister(struct pfil_head *ph) LIST_REMOVE(ph, ph_list); PFIL_LIST_UNLOCK(); - PFIL_WLOCK(ph); /* XXX: may sleep (cv_wait)! */ + PFIL_WLOCK(ph); TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext) free(pfh, M_IFADDR); TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext) free(pfh, M_IFADDR); - cv_destroy(&ph->ph_cv); - mtx_destroy(&ph->ph_mtx); + rw_destroy(&ph->ph_mtx); return (0); } @@ -269,13 +200,7 @@ pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, struct in } /* Lock */ - if (flags & PFIL_WAITOK) - PFIL_WLOCK(ph); - else { - err = PFIL_TRY_WLOCK(ph); - if (err) - goto error; - } + PFIL_WLOCK(ph); /* Add */ if (flags & PFIL_IN) { @@ -284,6 +209,7 @@ pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, struct in err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT); if (err) goto done; + ph->ph_nhooks++; } if (flags & PFIL_OUT) { pfh2->pfil_func = func; @@ -294,9 +220,9 @@ pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, struct in pfil_list_remove(&ph->ph_in, func, arg); goto done; } + ph->ph_nhooks++; } - ph->ph_busy_count = 0; PFIL_WUNLOCK(ph); return 0; @@ -320,22 +246,18 @@ pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, struct { int err = 0; - if (flags & PFIL_WAITOK) - PFIL_WLOCK(ph); - else { - err = PFIL_TRY_WLOCK(ph); - if (err) - return err; - } + PFIL_WLOCK(ph); - if (flags & PFIL_IN) + if (flags & PFIL_IN) { err = pfil_list_remove(&ph->ph_in, func, arg); - if ((err == 0) && (flags & PFIL_OUT)) + if (err == 0) + ph->ph_nhooks--; + } + if ((err == 0) && (flags & PFIL_OUT)) { err = pfil_list_remove(&ph->ph_out, func, arg); - - if (TAILQ_EMPTY(&ph->ph_in) && TAILQ_EMPTY(&ph->ph_out)) - ph->ph_busy_count = -1; - + if (err == 0) + ph->ph_nhooks--; + } PFIL_WUNLOCK(ph); return err; |