Index: head/sys/net/bpf.h =================================================================== --- head/sys/net/bpf.h +++ head/sys/net/bpf.h @@ -42,6 +42,9 @@ #ifndef _NET_BPF_H_ #define _NET_BPF_H_ +#include +#include + /* BSD style release date */ #define BPF_RELEASE 199606 @@ -233,9 +236,6 @@ u_int _bzh_pad[5]; }; -/* Pull in data-link level type codes. */ -#include - /* * The instruction encodings. * @@ -409,10 +409,11 @@ * bpf_peers_present() calls. */ struct bpf_if; +CK_LIST_HEAD(bpfd_list, bpf_d); struct bpf_if_ext { - LIST_ENTRY(bpf_if) bif_next; /* list of all interfaces */ - LIST_HEAD(, bpf_d) bif_dlist; /* descriptor list */ + CK_LIST_ENTRY(bpf_if) bif_next; /* list of all interfaces */ + struct bpfd_list bif_dlist; /* descriptor list */ }; void bpf_bufheld(struct bpf_d *d); @@ -436,7 +437,7 @@ struct bpf_if_ext *ext; ext = (struct bpf_if_ext *)bpf; - if (!LIST_EMPTY(&ext->bif_dlist)) + if (!CK_LIST_EMPTY(&ext->bif_dlist)) return (1); return (0); } Index: head/sys/net/bpf.c =================================================================== --- head/sys/net/bpf.c +++ head/sys/net/bpf.c @@ -3,6 +3,7 @@ * * Copyright (c) 1990, 1991, 1993 * The Regents of the University of California. All rights reserved. + * Copyright (c) 2019 Andrey V. Elsukov * * This code is derived from the Stanford/CMU enet packet filter, * (net/enet.c) distributed as part of 4.3BSD, and code contributed @@ -46,7 +47,6 @@ #include #include #include -#include #include #include #include @@ -99,7 +99,7 @@ MALLOC_DEFINE(M_BPF, "BPF", "BPF data"); static struct bpf_if_ext dead_bpf_if = { - .bif_dlist = LIST_HEAD_INITIALIZER() + .bif_dlist = CK_LIST_HEAD_INITIALIZER() }; struct bpf_if { @@ -108,19 +108,22 @@ struct bpf_if_ext bif_ext; /* public members */ u_int bif_dlt; /* link layer type */ u_int bif_hdrlen; /* length of link header */ + struct bpfd_list bif_wlist; /* writer-only list */ struct ifnet *bif_ifp; /* corresponding interface */ - struct rwlock bif_lock; /* interface lock */ - LIST_HEAD(, bpf_d) bif_wlist; /* writer-only list */ - int bif_flags; /* Interface flags */ struct bpf_if **bif_bpf; /* Pointer to pointer to us */ + volatile u_int bif_refcnt; + struct epoch_context epoch_ctx; }; CTASSERT(offsetof(struct bpf_if, bif_ext) == 0); -#define BPFIF_RLOCK(bif) rw_rlock(&(bif)->bif_lock) -#define BPFIF_RUNLOCK(bif) rw_runlock(&(bif)->bif_lock) -#define BPFIF_WLOCK(bif) rw_wlock(&(bif)->bif_lock) -#define BPFIF_WUNLOCK(bif) rw_wunlock(&(bif)->bif_lock) +struct bpf_program_buffer { + struct epoch_context epoch_ctx; +#ifdef BPF_JITTER + bpf_jit_filter *func; +#endif + void *buffer[0]; +}; #if defined(DEV_BPF) || defined(NETGRAPH_BPF) @@ -173,18 +176,24 @@ #define BPF_LOCK_ASSERT() sx_assert(&bpf_sx, SA_XLOCKED) /* * bpf_iflist is a list of BPF interface structures, each corresponding to a - * specific DLT. The same network interface might have several BPF interface + * specific DLT. The same network interface might have several BPF interface * structures registered by different layers in the stack (i.e., 802.11 * frames, ethernet frames, etc). */ -static LIST_HEAD(, bpf_if) bpf_iflist, bpf_freelist; +CK_LIST_HEAD(bpf_iflist, bpf_if); +static struct bpf_iflist bpf_iflist; static struct sx bpf_sx; /* bpf global lock */ static int bpf_bpfd_cnt; +static void bpfif_ref(struct bpf_if *); +static void bpfif_rele(struct bpf_if *); + +static void bpfd_ref(struct bpf_d *); +static void bpfd_rele(struct bpf_d *); static void bpf_attachd(struct bpf_d *, struct bpf_if *); static void bpf_detachd(struct bpf_d *); -static void bpf_detachd_locked(struct bpf_d *); -static void bpf_freed(struct bpf_d *); +static void bpf_detachd_locked(struct bpf_d *, bool); +static void bpfd_free(epoch_context_t); static int bpf_movein(struct uio *, int, struct ifnet *, struct mbuf **, struct sockaddr *, int *, struct bpf_d *); static int bpf_setif(struct bpf_d *, struct ifreq *); @@ -243,37 +252,106 @@ .f_event = filt_bpfread, }; -eventhandler_tag bpf_ifdetach_cookie = NULL; - /* - * LOCKING MODEL USED BY BPF: + * LOCKING MODEL USED BY BPF + * * Locks: - * 1) global lock (BPF_LOCK). Mutex, used to protect interface addition/removal, - * some global counters and every bpf_if reference. - * 2) Interface lock. Rwlock, used to protect list of BPF descriptors and their filters. - * 3) Descriptor lock. Mutex, used to protect BPF buffers and various structure fields - * used by bpf_mtap code. + * 1) global lock (BPF_LOCK). Sx, used to protect some global counters, + * every bpf_iflist changes, serializes ioctl access to bpf descriptors. + * 2) Descriptor lock. Mutex, used to protect BPF buffers and various + * structure fields used by bpf_*tap* code. * - * Lock order: + * Lock order: global lock, then descriptor lock. * - * Global lock, interface lock, descriptor lock + * There are several possible consumers: * - * We have to acquire interface lock before descriptor main lock due to BPF_MTAP[2] - * working model. In many places (like bpf_detachd) we start with BPF descriptor - * (and we need to at least rlock it to get reliable interface pointer). This - * gives us potential LOR. As a result, we use global lock to protect from bpf_if - * change in every such place. + * 1. The kernel registers interface pointer with bpfattach(). + * Each call allocates new bpf_if structure, references ifnet pointer + * and links bpf_if into bpf_iflist chain. This is protected with global + * lock. * - * Changing d->bd_bif is protected by 1) global lock, 2) interface lock and - * 3) descriptor main wlock. - * Reading bd_bif can be protected by any of these locks, typically global lock. + * 2. An userland application uses ioctl() call to bpf_d descriptor. + * All such call are serialized with global lock. BPF filters can be + * changed, but pointer to old filter will be freed using epoch_call(). + * Thus it should be safe for bpf_tap/bpf_mtap* code to do access to + * filter pointers, even if change will happen during bpf_tap execution. + * Destroying of bpf_d descriptor also is doing using epoch_call(). * - * Changing read/write BPF filter is protected by the same three locks, - * the same applies for reading. + * 3. An userland application can write packets into bpf_d descriptor. + * There we need to be sure, that ifnet won't disappear during bpfwrite(). * - * Sleeping in global lock is not allowed due to bpfdetach() using it. + * 4. The kernel invokes bpf_tap/bpf_mtap* functions. The access to + * bif_dlist is protected with net_epoch_preempt section. So, it should + * be safe to make access to bpf_d descriptor inside the section. + * + * 5. The kernel invokes bpfdetach() on interface destroying. All lists + * are modified with global lock held and actual free() is done using + * epoch_call(). */ +static void +bpfif_free(epoch_context_t ctx) +{ + struct bpf_if *bp; + + bp = __containerof(ctx, struct bpf_if, epoch_ctx); + if_rele(bp->bif_ifp); + free(bp, M_BPF); +} + +static void +bpfif_ref(struct bpf_if *bp) +{ + + refcount_acquire(&bp->bif_refcnt); +} + +static void +bpfif_rele(struct bpf_if *bp) +{ + + if (!refcount_release(&bp->bif_refcnt)) + return; + epoch_call(net_epoch_preempt, &bp->epoch_ctx, bpfif_free); +} + +static void +bpfd_ref(struct bpf_d *d) +{ + + refcount_acquire(&d->bd_refcnt); +} + +static void +bpfd_rele(struct bpf_d *d) +{ + + if (!refcount_release(&d->bd_refcnt)) + return; + epoch_call(net_epoch_preempt, &d->epoch_ctx, bpfd_free); +} + +static struct bpf_program_buffer* +bpf_program_buffer_alloc(size_t size, int flags) +{ + + return (malloc(sizeof(struct bpf_program_buffer) + size, + M_BPF, flags)); +} + +static void +bpf_program_buffer_free(epoch_context_t ctx) +{ + struct bpf_program_buffer *ptr; + + ptr = __containerof(ctx, struct bpf_program_buffer, epoch_ctx); +#ifdef BPF_JITTER + if (ptr->func != NULL) + bpf_destroy_jit_filter(ptr->func); +#endif + free(ptr, M_BPF); +} + /* * Wrapper functions for various buffering methods. If the set of buffer * modes expands, we will probably want to introduce a switch data structure @@ -627,7 +705,8 @@ } /* - * Attach file to the bpf interface, i.e. make d listen on bp. + * Attach descriptor to the bpf interface, i.e. make d listen on bp, + * then reset its buffers and counters with reset_d(). */ static void bpf_attachd(struct bpf_d *d, struct bpf_if *bp) @@ -643,7 +722,7 @@ op_w = V_bpf_optimize_writers || d->bd_writer; if (d->bd_bif != NULL) - bpf_detachd_locked(d); + bpf_detachd_locked(d, false); /* * Point d at bp, and add d to the interface's list. * Since there are many applications using BPF for @@ -652,26 +731,27 @@ * some filter is configured. */ - BPFIF_WLOCK(bp); BPFD_LOCK(d); - + /* + * Hold reference to bpif while descriptor uses this interface. + */ + bpfif_ref(bp); d->bd_bif = bp; - if (op_w != 0) { /* Add to writers-only list */ - LIST_INSERT_HEAD(&bp->bif_wlist, d, bd_next); + CK_LIST_INSERT_HEAD(&bp->bif_wlist, d, bd_next); /* * We decrement bd_writer on every filter set operation. * First BIOCSETF is done by pcap_open_live() to set up - * snap length. After that appliation usually sets its own filter + * snap length. After that appliation usually sets its own + * filter. */ d->bd_writer = 2; } else - LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); + CK_LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); + reset_d(d); BPFD_UNLOCK(d); - BPFIF_WUNLOCK(bp); - bpf_bpfd_cnt++; CTR3(KTR_NET, "%s: bpf_attach called by pid %d, adding to %s list", @@ -685,7 +765,8 @@ * Check if we need to upgrade our descriptor @d from write-only mode. */ static int -bpf_check_upgrade(u_long cmd, struct bpf_d *d, struct bpf_insn *fcode, int flen) +bpf_check_upgrade(u_long cmd, struct bpf_d *d, struct bpf_insn *fcode, + int flen) { int is_snap, need_upgrade; @@ -705,7 +786,8 @@ * we'd prefer to treat k=0 (deny ALL) case the same way: e.g. * do not consider upgrading immediately */ - if (cmd == BIOCSETF && flen == 1 && fcode[0].code == (BPF_RET | BPF_K)) + if (cmd == BIOCSETF && flen == 1 && + fcode[0].code == (BPF_RET | BPF_K)) is_snap = 1; else is_snap = 0; @@ -743,88 +825,45 @@ } /* - * Add d to the list of active bp filters. - * Requires bpf_attachd() to be called before. - */ -static void -bpf_upgraded(struct bpf_d *d) -{ - struct bpf_if *bp; - - BPF_LOCK_ASSERT(); - - bp = d->bd_bif; - - /* - * Filter can be set several times without specifying interface. - * Mark d as reader and exit. - */ - if (bp == NULL) { - BPFD_LOCK(d); - d->bd_writer = 0; - BPFD_UNLOCK(d); - return; - } - - BPFIF_WLOCK(bp); - BPFD_LOCK(d); - - /* Remove from writers-only list */ - LIST_REMOVE(d, bd_next); - LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); - /* Mark d as reader */ - d->bd_writer = 0; - - BPFD_UNLOCK(d); - BPFIF_WUNLOCK(bp); - - CTR2(KTR_NET, "%s: upgrade required by pid %d", __func__, d->bd_pid); - - EVENTHANDLER_INVOKE(bpf_track, bp->bif_ifp, bp->bif_dlt, 1); -} - -/* * Detach a file from its interface. */ static void bpf_detachd(struct bpf_d *d) { BPF_LOCK(); - bpf_detachd_locked(d); + bpf_detachd_locked(d, false); BPF_UNLOCK(); } static void -bpf_detachd_locked(struct bpf_d *d) +bpf_detachd_locked(struct bpf_d *d, bool detached_ifp) { - int error; struct bpf_if *bp; struct ifnet *ifp; + int error; + BPF_LOCK_ASSERT(); CTR2(KTR_NET, "%s: detach required by pid %d", __func__, d->bd_pid); - BPF_LOCK_ASSERT(); - /* Check if descriptor is attached */ if ((bp = d->bd_bif) == NULL) return; - BPFIF_WLOCK(bp); BPFD_LOCK(d); - + /* Remove d from the interface's descriptor list. */ + CK_LIST_REMOVE(d, bd_next); /* Save bd_writer value */ error = d->bd_writer; - - /* - * Remove d from the interface's descriptor list. - */ - LIST_REMOVE(d, bd_next); - ifp = bp->bif_ifp; d->bd_bif = NULL; + if (detached_ifp) { + /* + * Notify descriptor as it's detached, so that any + * sleepers wake up and get ENXIO. + */ + bpf_wakeup(d); + } BPFD_UNLOCK(d); - BPFIF_WUNLOCK(bp); - bpf_bpfd_cnt--; /* Call event handler iff d is attached */ @@ -833,9 +872,9 @@ /* * Check if this descriptor had requested promiscuous mode. - * If so, turn it off. + * If so and ifnet is not detached, turn it off. */ - if (d->bd_promisc) { + if (d->bd_promisc && !detached_ifp) { d->bd_promisc = 0; CURVNET_SET(ifp->if_vnet); error = ifpromisc(ifp, 0); @@ -851,6 +890,7 @@ "bpf_detach: ifpromisc failed (%d)\n", error); } } + bpfif_rele(bp); } /* @@ -875,8 +915,7 @@ seldrain(&d->bd_sel); knlist_destroy(&d->bd_sel.si_note); callout_drain(&d->bd_callout); - bpf_freed(d); - free(d, M_BPF); + bpfd_rele(d); } /* @@ -918,6 +957,7 @@ d->bd_bufmode = BPF_BUFMODE_BUFFER; d->bd_sig = SIGIO; d->bd_direction = BPF_D_INOUT; + d->bd_refcnt = 1; BPF_PID_REFRESH(d, td); #ifdef MAC mac_bpfdesc_init(d); @@ -1093,7 +1133,8 @@ BPFD_LOCK_ASSERT(d); - if (callout_pending(&d->bd_callout) || !callout_active(&d->bd_callout)) + if (callout_pending(&d->bd_callout) || + !callout_active(&d->bd_callout)) return; if (d->bd_state == BPF_WAITING) { d->bd_state = BPF_TIMED_OUT; @@ -1119,47 +1160,71 @@ static int bpfwrite(struct cdev *dev, struct uio *uio, int ioflag) { + struct route ro; + struct sockaddr dst; + struct epoch_tracker et; + struct bpf_if *bp; struct bpf_d *d; struct ifnet *ifp; struct mbuf *m, *mc; - struct sockaddr dst; - struct route ro; int error, hlen; error = devfs_get_cdevpriv((void **)&d); if (error != 0) return (error); + NET_EPOCH_ENTER(et); + BPFD_LOCK(d); BPF_PID_REFRESH_CUR(d); counter_u64_add(d->bd_wcount, 1); - /* XXX: locking required */ - if (d->bd_bif == NULL) { - counter_u64_add(d->bd_wdcount, 1); - return (ENXIO); + if ((bp = d->bd_bif) == NULL) { + error = ENXIO; + goto out_locked; } - ifp = d->bd_bif->bif_ifp; - + ifp = bp->bif_ifp; if ((ifp->if_flags & IFF_UP) == 0) { - counter_u64_add(d->bd_wdcount, 1); - return (ENETDOWN); + error = ENETDOWN; + goto out_locked; } - if (uio->uio_resid == 0) { - counter_u64_add(d->bd_wdcount, 1); - return (0); - } + if (uio->uio_resid == 0) + goto out_locked; bzero(&dst, sizeof(dst)); m = NULL; hlen = 0; - /* XXX: bpf_movein() can sleep */ - error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp, + + /* + * Take extra reference, unlock d and exit from epoch section, + * since bpf_movein() can sleep. + */ + bpfd_ref(d); + NET_EPOCH_EXIT(et); + BPFD_UNLOCK(d); + + error = bpf_movein(uio, (int)bp->bif_dlt, ifp, &m, &dst, &hlen, d); - if (error) { + + if (error != 0) { counter_u64_add(d->bd_wdcount, 1); + bpfd_rele(d); return (error); } + + BPFD_LOCK(d); + /* + * Check that descriptor is still attached to the interface. + * This can happen on bpfdetach(). To avoid access to detached + * ifnet, free mbuf and return ENXIO. + */ + if (d->bd_bif == NULL) { + counter_u64_add(d->bd_wdcount, 1); + BPFD_UNLOCK(d); + bpfd_rele(d); + m_freem(m); + return (ENXIO); + } counter_u64_add(d->bd_wfcount, 1); if (d->bd_hdrcmplt) dst.sa_family = pseudo_AF_HDRCMPLT; @@ -1180,11 +1245,9 @@ CURVNET_SET(ifp->if_vnet); #ifdef MAC - BPFD_LOCK(d); mac_bpfdesc_create_mbuf(d, m); if (mc != NULL) mac_bpfdesc_create_mbuf(d, mc); - BPFD_UNLOCK(d); #endif bzero(&ro, sizeof(ro)); @@ -1205,7 +1268,14 @@ m_freem(mc); } CURVNET_RESTORE(); + BPFD_UNLOCK(d); + bpfd_rele(d); + return (error); +out_locked: + counter_u64_add(d->bd_wdcount, 1); + NET_EPOCH_EXIT(et); + BPFD_UNLOCK(d); return (error); } @@ -1830,16 +1900,11 @@ } /* - * Set d's packet filter program to fp. If this file already has a filter, - * free it and replace it. Returns EINVAL for bogus requests. + * Set d's packet filter program to fp. If this file already has a filter, + * free it and replace it. Returns EINVAL for bogus requests. * - * Note we need global lock here to serialize bpf_setf() and bpf_setif() calls - * since reading d->bd_bif can't be protected by d or interface lock due to - * lock order. - * - * Additionally, we have to acquire interface write lock due to bpf_mtap() uses - * interface read lock to read all filers. - * + * Note we use global lock here to serialize bpf_setf() and bpf_setif() + * calls. */ static int bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd) @@ -1848,13 +1913,14 @@ struct bpf_program fp_swab; struct bpf_program32 *fp32; #endif - struct bpf_insn *fcode, *old; + struct bpf_program_buffer *fcode; + struct bpf_insn *filter; #ifdef BPF_JITTER - bpf_jit_filter *jfunc, *ofunc; + bpf_jit_filter *jfunc; #endif size_t size; u_int flen; - int need_upgrade; + bool track_event; #ifdef COMPAT_FREEBSD32 switch (cmd) { @@ -1863,7 +1929,8 @@ case BIOCSETFNR32: fp32 = (struct bpf_program32 *)fp; fp_swab.bf_len = fp32->bf_len; - fp_swab.bf_insns = (struct bpf_insn *)(uintptr_t)fp32->bf_insns; + fp_swab.bf_insns = + (struct bpf_insn *)(uintptr_t)fp32->bf_insns; fp = &fp_swab; switch (cmd) { case BIOCSETF32: @@ -1877,12 +1944,10 @@ } #endif - fcode = NULL; + filter = NULL; #ifdef BPF_JITTER - jfunc = ofunc = NULL; + jfunc = NULL; #endif - need_upgrade = 0; - /* * Check new filter validness before acquiring any locks. * Allocate memory for new filter, if needed. @@ -1892,10 +1957,11 @@ return (EINVAL); size = flen * sizeof(*fp->bf_insns); if (size > 0) { - /* We're setting up new filter. Copy and check actual data. */ - fcode = malloc(size, M_BPF, M_WAITOK); - if (copyin(fp->bf_insns, fcode, size) != 0 || - !bpf_validate(fcode, flen)) { + /* We're setting up new filter. Copy and check actual data. */ + fcode = bpf_program_buffer_alloc(size, M_WAITOK); + filter = (struct bpf_insn *)fcode->buffer; + if (copyin(fp->bf_insns, filter, size) != 0 || + !bpf_validate(filter, flen)) { free(fcode, M_BPF); return (EINVAL); } @@ -1905,50 +1971,73 @@ * Filter is copied inside fcode and is * perfectly valid. */ - jfunc = bpf_jitter(fcode, flen); + jfunc = bpf_jitter(filter, flen); } #endif } - BPF_LOCK(); + track_event = false; + fcode = NULL; - /* - * Set up new filter. - * Protect filter change by interface lock. - * Additionally, we are protected by global lock here. - */ - if (d->bd_bif != NULL) - BPFIF_WLOCK(d->bd_bif); + BPF_LOCK(); BPFD_LOCK(d); + /* Set up new filter. */ if (cmd == BIOCSETWF) { - old = d->bd_wfilter; - d->bd_wfilter = fcode; + if (d->bd_wfilter != NULL) { + fcode = __containerof((void *)d->bd_wfilter, + struct bpf_program_buffer, buffer); +#ifdef BPF_JITTER + fcode->func = NULL; +#endif + } + d->bd_wfilter = filter; } else { - old = d->bd_rfilter; - d->bd_rfilter = fcode; + if (d->bd_rfilter != NULL) { + fcode = __containerof((void *)d->bd_rfilter, + struct bpf_program_buffer, buffer); #ifdef BPF_JITTER - ofunc = d->bd_bfilter; + fcode->func = d->bd_bfilter; +#endif + } + d->bd_rfilter = filter; +#ifdef BPF_JITTER d->bd_bfilter = jfunc; #endif if (cmd == BIOCSETF) reset_d(d); - need_upgrade = bpf_check_upgrade(cmd, d, fcode, flen); + if (bpf_check_upgrade(cmd, d, filter, flen) != 0) { + /* + * Filter can be set several times without + * specifying interface. In this case just mark d + * as reader. + */ + d->bd_writer = 0; + if (d->bd_bif != NULL) { + /* + * Remove descriptor from writers-only list + * and add it to active readers list. + */ + CK_LIST_REMOVE(d, bd_next); + CK_LIST_INSERT_HEAD(&d->bd_bif->bif_dlist, + d, bd_next); + CTR2(KTR_NET, + "%s: upgrade required by pid %d", + __func__, d->bd_pid); + track_event = true; + } + } } BPFD_UNLOCK(d); - if (d->bd_bif != NULL) - BPFIF_WUNLOCK(d->bd_bif); - if (old != NULL) - free(old, M_BPF); -#ifdef BPF_JITTER - if (ofunc != NULL) - bpf_destroy_jit_filter(ofunc); -#endif - /* Move d to active readers list. */ - if (need_upgrade != 0) - bpf_upgraded(d); + if (fcode != NULL) + epoch_call(net_epoch_preempt, &fcode->epoch_ctx, + bpf_program_buffer_free); + if (track_event) + EVENTHANDLER_INVOKE(bpf_track, + d->bd_bif->bif_ifp, d->bd_bif->bif_dlt, 1); + BPF_UNLOCK(); return (0); } @@ -1971,15 +2060,6 @@ return (ENXIO); bp = theywant->if_bpf; - - /* Check if interface is not being detached from BPF */ - BPFIF_RLOCK(bp); - if (bp->bif_flags & BPFIF_FLAG_DYING) { - BPFIF_RUNLOCK(bp); - return (ENXIO); - } - BPFIF_RUNLOCK(bp); - /* * At this point, we expect the buffer is already allocated. If not, * return an error. @@ -1996,9 +2076,11 @@ } if (bp != d->bd_bif) bpf_attachd(d, bp); - BPFD_LOCK(d); - reset_d(d); - BPFD_UNLOCK(d); + else { + BPFD_LOCK(d); + reset_d(d); + BPFD_UNLOCK(d); + } return (0); } @@ -2150,6 +2232,7 @@ void bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) { + struct epoch_tracker et; struct bintime bt; struct bpf_d *d; #ifdef BPF_JITTER @@ -2159,24 +2242,14 @@ int gottime; gottime = BPF_TSTAMP_NONE; - - BPFIF_RLOCK(bp); - - LIST_FOREACH(d, &bp->bif_dlist, bd_next) { - /* - * We are not using any locks for d here because: - * 1) any filter change is protected by interface - * write lock - * 2) destroying/detaching d is protected by interface - * write lock, too - */ - + NET_EPOCH_ENTER(et); + CK_LIST_FOREACH(d, &bp->bif_dlist, bd_next) { counter_u64_add(d->bd_rcount, 1); /* - * NB: We dont call BPF_CHECK_DIRECTION() here since there is no - * way for the caller to indiciate to us whether this packet - * is inbound or outbound. In the bpf_mtap() routines, we use - * the interface pointers on the mbuf to figure it out. + * NB: We dont call BPF_CHECK_DIRECTION() here since there + * is no way for the caller to indiciate to us whether this + * packet is inbound or outbound. In the bpf_mtap() routines, + * we use the interface pointers on the mbuf to figure it out. */ #ifdef BPF_JITTER bf = bpf_jitter_enable != 0 ? d->bd_bfilter : NULL; @@ -2190,10 +2263,10 @@ * Filter matches. Let's to acquire write lock. */ BPFD_LOCK(d); - counter_u64_add(d->bd_fcount, 1); if (gottime < bpf_ts_quality(d->bd_tstamp)) - gottime = bpf_gettime(&bt, d->bd_tstamp, NULL); + gottime = bpf_gettime(&bt, d->bd_tstamp, + NULL); #ifdef MAC if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0) #endif @@ -2202,7 +2275,7 @@ BPFD_UNLOCK(d); } } - BPFIF_RUNLOCK(bp); + NET_EPOCH_EXIT(et); } #define BPF_CHECK_DIRECTION(d, r, i) \ @@ -2216,6 +2289,7 @@ void bpf_mtap(struct bpf_if *bp, struct mbuf *m) { + struct epoch_tracker et; struct bintime bt; struct bpf_d *d; #ifdef BPF_JITTER @@ -2233,9 +2307,8 @@ pktlen = m_length(m, NULL); gottime = BPF_TSTAMP_NONE; - BPFIF_RLOCK(bp); - - LIST_FOREACH(d, &bp->bif_dlist, bd_next) { + NET_EPOCH_ENTER(et); + CK_LIST_FOREACH(d, &bp->bif_dlist, bd_next) { if (BPF_CHECK_DIRECTION(d, m->m_pkthdr.rcvif, bp->bif_ifp)) continue; counter_u64_add(d->bd_rcount, 1); @@ -2243,7 +2316,8 @@ bf = bpf_jitter_enable != 0 ? d->bd_bfilter : NULL; /* XXX We cannot handle multiple mbufs. */ if (bf != NULL && m->m_next == NULL) - slen = (*(bf->func))(mtod(m, u_char *), pktlen, pktlen); + slen = (*(bf->func))(mtod(m, u_char *), pktlen, + pktlen); else #endif slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0); @@ -2261,7 +2335,7 @@ BPFD_UNLOCK(d); } } - BPFIF_RUNLOCK(bp); + NET_EPOCH_EXIT(et); } /* @@ -2271,6 +2345,7 @@ void bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m) { + struct epoch_tracker et; struct bintime bt; struct mbuf mb; struct bpf_d *d; @@ -2296,9 +2371,8 @@ gottime = BPF_TSTAMP_NONE; - BPFIF_RLOCK(bp); - - LIST_FOREACH(d, &bp->bif_dlist, bd_next) { + NET_EPOCH_ENTER(et); + CK_LIST_FOREACH(d, &bp->bif_dlist, bd_next) { if (BPF_CHECK_DIRECTION(d, m->m_pkthdr.rcvif, bp->bif_ifp)) continue; counter_u64_add(d->bd_rcount, 1); @@ -2317,11 +2391,10 @@ BPFD_UNLOCK(d); } } - BPFIF_RUNLOCK(bp); + NET_EPOCH_EXIT(et); } #undef BPF_CHECK_DIRECTION - #undef BPF_TSTAMP_NONE #undef BPF_TSTAMP_FAST #undef BPF_TSTAMP_NORMAL @@ -2540,26 +2613,30 @@ * Called on close. */ static void -bpf_freed(struct bpf_d *d) +bpfd_free(epoch_context_t ctx) { + struct bpf_d *d; + struct bpf_program_buffer *p; /* * We don't need to lock out interrupts since this descriptor has * been detached from its interface and it yet hasn't been marked * free. */ + d = __containerof(ctx, struct bpf_d, epoch_ctx); bpf_free(d); if (d->bd_rfilter != NULL) { - free((caddr_t)d->bd_rfilter, M_BPF); -#ifdef BPF_JITTER - if (d->bd_bfilter != NULL) - bpf_destroy_jit_filter(d->bd_bfilter); -#endif + p = __containerof((void *)d->bd_rfilter, + struct bpf_program_buffer, buffer); + bpf_program_buffer_free(&p->epoch_ctx); } - if (d->bd_wfilter != NULL) - free((caddr_t)d->bd_wfilter, M_BPF); - mtx_destroy(&d->bd_lock); + if (d->bd_wfilter != NULL) { + p = __containerof((void *)d->bd_wfilter, + struct bpf_program_buffer, buffer); + bpf_program_buffer_free(&p->epoch_ctx); + } + mtx_destroy(&d->bd_lock); counter_u64_free(d->bd_rcount); counter_u64_free(d->bd_dcount); counter_u64_free(d->bd_fcount); @@ -2567,7 +2644,7 @@ counter_u64_free(d->bd_wfcount); counter_u64_free(d->bd_wdcount); counter_u64_free(d->bd_zcopy); - + free(d, M_BPF); } /* @@ -2588,25 +2665,31 @@ * headers are not yet supporrted). */ void -bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) +bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, + struct bpf_if **driverp) { struct bpf_if *bp; - KASSERT(*driverp == NULL, ("bpfattach2: driverp already initialized")); + KASSERT(*driverp == NULL, + ("bpfattach2: driverp already initialized")); bp = malloc(sizeof(*bp), M_BPF, M_WAITOK | M_ZERO); - rw_init(&bp->bif_lock, "bpf interface lock"); - LIST_INIT(&bp->bif_dlist); - LIST_INIT(&bp->bif_wlist); + CK_LIST_INIT(&bp->bif_dlist); + CK_LIST_INIT(&bp->bif_wlist); bp->bif_ifp = ifp; bp->bif_dlt = dlt; bp->bif_hdrlen = hdrlen; bp->bif_bpf = driverp; + bp->bif_refcnt = 1; *driverp = bp; - + /* + * Reference ifnet pointer, so it won't freed until + * we release it. + */ + if_ref(ifp); BPF_LOCK(); - LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next); + CK_LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next); BPF_UNLOCK(); if (bootverbose && IS_DEFAULT_VNET(curvnet)) @@ -2647,103 +2730,37 @@ void bpfdetach(struct ifnet *ifp) { - struct bpf_if *bp, *bp_temp; - struct bpf_d *d; - int ndetached; + struct bpf_if *bp, *bp_temp; + struct bpf_d *d; - ndetached = 0; - BPF_LOCK(); /* Find all bpf_if struct's which reference ifp and detach them. */ - LIST_FOREACH_SAFE(bp, &bpf_iflist, bif_next, bp_temp) { + CK_LIST_FOREACH_SAFE(bp, &bpf_iflist, bif_next, bp_temp) { if (ifp != bp->bif_ifp) continue; - LIST_REMOVE(bp, bif_next); - /* Add to to-be-freed list */ - LIST_INSERT_HEAD(&bpf_freelist, bp, bif_next); - - ndetached++; - /* - * Delay freeing bp till interface is detached - * and all routes through this interface are removed. - * Mark bp as detached to restrict new consumers. - */ - BPFIF_WLOCK(bp); - bp->bif_flags |= BPFIF_FLAG_DYING; + CK_LIST_REMOVE(bp, bif_next); *bp->bif_bpf = (struct bpf_if *)&dead_bpf_if; - BPFIF_WUNLOCK(bp); - CTR4(KTR_NET, "%s: sheduling free for encap %d (%p) for if %p", + CTR4(KTR_NET, + "%s: sheduling free for encap %d (%p) for if %p", __func__, bp->bif_dlt, bp, ifp); - /* Free common descriptors */ - while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) { - bpf_detachd_locked(d); - BPFD_LOCK(d); - bpf_wakeup(d); - BPFD_UNLOCK(d); + /* Detach common descriptors */ + while ((d = CK_LIST_FIRST(&bp->bif_dlist)) != NULL) { + bpf_detachd_locked(d, true); } - /* Free writer-only descriptors */ - while ((d = LIST_FIRST(&bp->bif_wlist)) != NULL) { - bpf_detachd_locked(d); - BPFD_LOCK(d); - bpf_wakeup(d); - BPFD_UNLOCK(d); + /* Detach writer-only descriptors */ + while ((d = CK_LIST_FIRST(&bp->bif_wlist)) != NULL) { + bpf_detachd_locked(d, true); } + bpfif_rele(bp); } BPF_UNLOCK(); - -#ifdef INVARIANTS - if (ndetached == 0) - printf("bpfdetach: %s was not attached\n", ifp->if_xname); -#endif } /* - * Interface departure handler. - * Note departure event does not guarantee interface is going down. - * Interface renaming is currently done via departure/arrival event set. - * - * Departure handled is called after all routes pointing to - * given interface are removed and interface is in down state - * restricting any packets to be sent/received. We assume it is now safe - * to free data allocated by BPF. - */ -static void -bpf_ifdetach(void *arg __unused, struct ifnet *ifp) -{ - struct bpf_if *bp, *bp_temp; - int nmatched = 0; - - /* Ignore ifnet renaming. */ - if (ifp->if_flags & IFF_RENAMING) - return; - - BPF_LOCK(); - /* - * Find matching entries in free list. - * Nothing should be found if bpfdetach() was not called. - */ - LIST_FOREACH_SAFE(bp, &bpf_freelist, bif_next, bp_temp) { - if (ifp != bp->bif_ifp) - continue; - - CTR3(KTR_NET, "%s: freeing BPF instance %p for interface %p", - __func__, bp, ifp); - - LIST_REMOVE(bp, bif_next); - - rw_destroy(&bp->bif_lock); - free(bp, M_BPF); - - nmatched++; - } - BPF_UNLOCK(); -} - -/* * Get a list of available data link type of the interface. */ static int @@ -2757,9 +2774,8 @@ BPF_LOCK_ASSERT(); ifp = d->bd_bif->bif_ifp; -again: n1 = 0; - LIST_FOREACH(bp, &bpf_iflist, bif_next) { + CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) { if (bp->bif_ifp == ifp) n1++; } @@ -2769,24 +2785,16 @@ } if (n1 > bfl->bfl_len) return (ENOMEM); - BPF_UNLOCK(); + lst = malloc(n1 * sizeof(u_int), M_TEMP, M_WAITOK); n = 0; - BPF_LOCK(); - LIST_FOREACH(bp, &bpf_iflist, bif_next) { + CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) { if (bp->bif_ifp != ifp) continue; - if (n >= n1) { - free(lst, M_TEMP); - goto again; - } - lst[n] = bp->bif_dlt; - n++; + lst[n++] = bp->bif_dlt; } - BPF_UNLOCK(); error = copyout(lst, bfl->bfl_list, sizeof(u_int) * n); free(lst, M_TEMP); - BPF_LOCK(); bfl->bfl_len = n; return (error); } @@ -2802,33 +2810,34 @@ struct bpf_if *bp; BPF_LOCK_ASSERT(); + MPASS(d->bd_bif != NULL); + /* + * It is safe to check bd_bif without BPFD_LOCK, it can not be + * changed while we hold global lock. + */ if (d->bd_bif->bif_dlt == dlt) return (0); - ifp = d->bd_bif->bif_ifp; - LIST_FOREACH(bp, &bpf_iflist, bif_next) { + ifp = d->bd_bif->bif_ifp; + CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) { if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) break; } + if (bp == NULL) + return (EINVAL); - if (bp != NULL) { - opromisc = d->bd_promisc; - bpf_attachd(d, bp); - BPFD_LOCK(d); - reset_d(d); - BPFD_UNLOCK(d); - if (opromisc) { - error = ifpromisc(bp->bif_ifp, 1); - if (error) - if_printf(bp->bif_ifp, - "bpf_setdlt: ifpromisc failed (%d)\n", - error); - else - d->bd_promisc = 1; - } + opromisc = d->bd_promisc; + bpf_attachd(d, bp); + if (opromisc) { + error = ifpromisc(bp->bif_ifp, 1); + if (error) + if_printf(bp->bif_ifp, "%s: ifpromisc failed (%d)\n", + __func__, error); + else + d->bd_promisc = 1; } - return (bp == NULL ? EINVAL : 0); + return (0); } static void @@ -2837,17 +2846,11 @@ struct cdev *dev; sx_init(&bpf_sx, "bpf global lock"); - LIST_INIT(&bpf_iflist); - LIST_INIT(&bpf_freelist); + CK_LIST_INIT(&bpf_iflist); dev = make_dev(&bpf_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "bpf"); /* For compatibility */ make_dev_alias(dev, "bpf0"); - - /* Register interface departure handler */ - bpf_ifdetach_cookie = EVENTHANDLER_REGISTER( - ifnet_departure_event, bpf_ifdetach, NULL, - EVENTHANDLER_PRI_ANY); } /* @@ -2862,19 +2865,19 @@ struct bpf_d *bd; BPF_LOCK(); - LIST_FOREACH(bp, &bpf_iflist, bif_next) { - BPFIF_RLOCK(bp); - LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { - BPFD_LOCK(bd); + /* + * We are protected by global lock here, interfaces and + * descriptors can not be deleted while we hold it. + */ + CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) { + CK_LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { counter_u64_zero(bd->bd_rcount); counter_u64_zero(bd->bd_dcount); counter_u64_zero(bd->bd_fcount); counter_u64_zero(bd->bd_wcount); counter_u64_zero(bd->bd_wfcount); counter_u64_zero(bd->bd_zcopy); - BPFD_UNLOCK(bd); } - BPFIF_RUNLOCK(bp); } BPF_UNLOCK(); } @@ -2886,10 +2889,9 @@ bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd) { + BPF_LOCK_ASSERT(); bzero(d, sizeof(*d)); - BPFD_LOCK_ASSERT(bd); d->bd_structsize = sizeof(*d); - /* XXX: reading should be protected by global lock */ d->bd_immediate = bd->bd_immediate; d->bd_promisc = bd->bd_promisc; d->bd_hdrcmplt = bd->bd_hdrcmplt; @@ -2964,22 +2966,16 @@ return (ENOMEM); } index = 0; - LIST_FOREACH(bp, &bpf_iflist, bif_next) { - BPFIF_RLOCK(bp); + CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) { /* Send writers-only first */ - LIST_FOREACH(bd, &bp->bif_wlist, bd_next) { + CK_LIST_FOREACH(bd, &bp->bif_wlist, bd_next) { xbd = &xbdbuf[index++]; - BPFD_LOCK(bd); bpfstats_fill_xbpf(xbd, bd); - BPFD_UNLOCK(bd); } - LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { + CK_LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { xbd = &xbdbuf[index++]; - BPFD_LOCK(bd); bpfstats_fill_xbpf(xbd, bd); - BPFD_UNLOCK(bd); } - BPFIF_RUNLOCK(bp); } BPF_UNLOCK(); error = SYSCTL_OUT(req, xbdbuf, index * sizeof(*xbd)); @@ -3059,10 +3055,10 @@ /* bif_ext.bif_dlist */ BPF_DB_PRINTF("%#x", bif_dlt); BPF_DB_PRINTF("%u", bif_hdrlen); - BPF_DB_PRINTF("%p", bif_ifp); - /* bif_lock */ /* bif_wlist */ - BPF_DB_PRINTF("%#x", bif_flags); + BPF_DB_PRINTF("%p", bif_ifp); + BPF_DB_PRINTF("%p", bif_bpf); + BPF_DB_PRINTF("%u", bif_refcnt); } DB_SHOW_COMMAND(bpf_if, db_show_bpf_if) Index: head/sys/net/bpfdesc.h =================================================================== --- head/sys/net/bpfdesc.h +++ head/sys/net/bpfdesc.h @@ -43,9 +43,10 @@ #include #include -#include +#include #include #include +#include #include /* @@ -53,7 +54,7 @@ */ struct zbuf; struct bpf_d { - LIST_ENTRY(bpf_d) bd_next; /* Linked list of descriptors */ + CK_LIST_ENTRY(bpf_d) bd_next; /* Linked list of descriptors */ /* * Buffer slots: two memory buffers store the incoming packets. * The model has three slots. Sbuf is always occupied. @@ -104,6 +105,9 @@ counter_u64_t bd_wdcount; /* number of packets dropped during a write */ counter_u64_t bd_zcopy; /* number of zero copy operations */ u_char bd_compat32; /* 32-bit stream on LP64 system */ + + volatile u_int bd_refcnt; + struct epoch_context epoch_ctx; }; /* Values for bd_state */