/* $OpenBSD: bpf.c,v 1.138 2016/04/02 08:49:49 dlg Exp $ */ /* $NetBSD: bpf.c,v 1.33 1997/02/21 23:59:35 thorpej Exp $ */ /* * Copyright (c) 1990, 1991, 1993 * The Regents of the University of California. All rights reserved. * Copyright (c) 2010, 2014 Henning Brauer * * This code is derived from the Stanford/CMU enet packet filter, * (net/enet.c) distributed as part of 4.3BSD, and code contributed * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence * Berkeley Laboratory. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)bpf.c 8.2 (Berkeley) 3/28/94 */ #include "bpfilter.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "vlan.h" #if NVLAN > 0 #include #endif #define BPF_BUFSIZE 32768 #define PRINET 26 /* interruptible */ /* from kern/kern_clock.c; incremented each clock tick. */ extern int ticks; /* * The default read buffer size is patchable. */ int bpf_bufsize = BPF_BUFSIZE; int bpf_maxbufsize = BPF_MAXBUFSIZE; /* * bpf_iflist is the list of interfaces; each corresponds to an ifnet * bpf_d_list is the list of descriptors */ struct bpf_if *bpf_iflist; LIST_HEAD(, bpf_d) bpf_d_list; void bpf_allocbufs(struct bpf_d *); void bpf_freed(struct bpf_d *); void bpf_ifname(struct ifnet *, struct ifreq *); int _bpf_mtap(caddr_t, struct mbuf *, u_int, void (*)(const void *, void *, size_t)); void bpf_mcopy(const void *, void *, size_t); int bpf_movein(struct uio *, u_int, struct mbuf **, struct sockaddr *, struct bpf_insn *); void bpf_attachd(struct bpf_d *, struct bpf_if *); void bpf_detachd(struct bpf_d *); int bpf_setif(struct bpf_d *, struct ifreq *); int bpfpoll(dev_t, int, struct proc *); int bpfkqfilter(dev_t, struct knote *); void bpf_wakeup(struct bpf_d *); void bpf_catchpacket(struct bpf_d *, u_char *, size_t, size_t, void (*)(const void *, void *, size_t), struct timeval *); void bpf_reset_d(struct bpf_d *); int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); int bpf_setdlt(struct bpf_d *, u_int); void filt_bpfrdetach(struct knote *); int filt_bpfread(struct knote *, long); int bpf_sysctl_locked(int *, u_int, void *, size_t *, void *, size_t); struct bpf_d *bpfilter_lookup(int); struct bpf_d *bpfilter_create(int); void bpfilter_destroy(struct bpf_d *); /* * Reference count access to descriptor buffers */ #define D_GET(d) ((d)->bd_ref++) #define D_PUT(d) bpf_freed(d) /* * garbage collector srps */ void bpf_d_ref(void *, void *); void bpf_d_unref(void *, void *); struct srpl_rc bpf_d_rc = SRPL_RC_INITIALIZER(bpf_d_ref, bpf_d_unref, NULL); void bpf_insn_dtor(void *, void *); struct srp_gc bpf_insn_gc = SRP_GC_INITIALIZER(bpf_insn_dtor, NULL); int bpf_movein(struct uio *uio, u_int linktype, struct mbuf **mp, struct sockaddr *sockp, struct bpf_insn *filter) { struct mbuf *m; struct m_tag *mtag; int error; u_int hlen; u_int len; u_int slen; /* * Build a sockaddr based on the data link layer type. * We do this at this level because the ethernet header * is copied directly into the data field of the sockaddr. * In the case of SLIP, there is no header and the packet * is forwarded as is. * Also, we are careful to leave room at the front of the mbuf * for the link level header. */ switch (linktype) { case DLT_SLIP: sockp->sa_family = AF_INET; hlen = 0; break; case DLT_PPP: sockp->sa_family = AF_UNSPEC; hlen = 0; break; case DLT_EN10MB: sockp->sa_family = AF_UNSPEC; /* XXX Would MAXLINKHDR be better? */ hlen = ETHER_HDR_LEN; break; case DLT_IEEE802_11: case DLT_IEEE802_11_RADIO: sockp->sa_family = AF_UNSPEC; hlen = 0; break; case DLT_RAW: case DLT_NULL: sockp->sa_family = AF_UNSPEC; hlen = 0; break; case DLT_LOOP: sockp->sa_family = AF_UNSPEC; hlen = sizeof(u_int32_t); break; default: return (EIO); } if (uio->uio_resid > MAXMCLBYTES) return (EIO); len = uio->uio_resid; MGETHDR(m, M_WAIT, MT_DATA); m->m_pkthdr.ph_ifidx = 0; m->m_pkthdr.len = len - hlen; if (len > MHLEN) { MCLGETI(m, M_WAIT, NULL, len); if ((m->m_flags & M_EXT) == 0) { error = ENOBUFS; goto bad; } } m->m_len = len; *mp = m; error = uiomove(mtod(m, caddr_t), len, uio); if (error) goto bad; slen = bpf_filter(filter, mtod(m, u_char *), len, len); if (slen < len) { error = EPERM; goto bad; } if (m->m_len < hlen) { error = EPERM; goto bad; } /* * Make room for link header, and copy it to sockaddr */ if (hlen != 0) { if (linktype == DLT_LOOP) { u_int32_t af; /* the link header indicates the address family */ KASSERT(hlen == sizeof(u_int32_t)); memcpy(&af, m->m_data, hlen); sockp->sa_family = ntohl(af); } else memcpy(sockp->sa_data, m->m_data, hlen); m->m_len -= hlen; m->m_data += hlen; /* XXX */ } /* * Prepend the data link type as a mbuf tag */ mtag = m_tag_get(PACKET_TAG_DLT, sizeof(u_int), M_WAIT); *(u_int *)(mtag + 1) = linktype; m_tag_prepend(m, mtag); return (0); bad: m_freem(m); return (error); } /* * Attach file to the bpf interface, i.e. make d listen on bp. * Must be called at splnet. */ void bpf_attachd(struct bpf_d *d, struct bpf_if *bp) { /* * Point d at bp, and add d to the interface's list of listeners. * Finally, point the driver's bpf cookie at the interface so * it will divert packets to bpf. */ d->bd_bif = bp; KERNEL_ASSERT_LOCKED(); SRPL_INSERT_HEAD_LOCKED(&bpf_d_rc, &bp->bif_dlist, d, bd_next); *bp->bif_driverp = bp; } /* * Detach a file from its interface. */ void bpf_detachd(struct bpf_d *d) { struct bpf_if *bp; bp = d->bd_bif; /* * Check if this descriptor had requested promiscuous mode. * If so, turn it off. */ if (d->bd_promisc) { int error; d->bd_promisc = 0; error = ifpromisc(bp->bif_ifp, 0); if (error && !(error == EINVAL || error == ENODEV)) /* * Something is really wrong if we were able to put * the driver into promiscuous mode, but can't * take it out. */ panic("bpf: ifpromisc failed"); } /* Remove d from the interface's descriptor list. */ KERNEL_ASSERT_LOCKED(); SRPL_REMOVE_LOCKED(&bpf_d_rc, &bp->bif_dlist, d, bpf_d, bd_next); if (SRPL_EMPTY_LOCKED(&bp->bif_dlist)) { /* * Let the driver know that there are no more listeners. */ *d->bd_bif->bif_driverp = 0; } d->bd_bif = NULL; } void bpfilterattach(int n) { LIST_INIT(&bpf_d_list); } /* * Open ethernet device. Returns ENXIO for illegal minor device number, * EBUSY if file is open by another process. */ int bpfopen(dev_t dev, int flag, int mode, struct proc *p) { struct bpf_d *d; /* create on demand */ if ((d = bpfilter_create(minor(dev))) == NULL) return (EBUSY); /* Mark "free" and do most initialization. */ d->bd_bufsize = bpf_bufsize; d->bd_sig = SIGIO; if (flag & FNONBLOCK) d->bd_rtout = -1; D_GET(d); return (0); } /* * Close the descriptor by detaching it from its interface, * deallocating its buffers, and marking it free. */ int bpfclose(dev_t dev, int flag, int mode, struct proc *p) { struct bpf_d *d; int s; d = bpfilter_lookup(minor(dev)); s = splnet(); if (d->bd_bif) bpf_detachd(d); bpf_wakeup(d); D_PUT(d); splx(s); return (0); } /* * Rotate the packet buffers in descriptor d. Move the store buffer * into the hold slot, and the free buffer into the store slot. * Zero the length of the new store buffer. */ #define ROTATE_BUFFERS(d) \ (d)->bd_hbuf = (d)->bd_sbuf; \ (d)->bd_hlen = (d)->bd_slen; \ (d)->bd_sbuf = (d)->bd_fbuf; \ (d)->bd_slen = 0; \ (d)->bd_fbuf = 0; /* * bpfread - read next chunk of packets from buffers */ int bpfread(dev_t dev, struct uio *uio, int ioflag) { struct bpf_d *d; int error; int s; d = bpfilter_lookup(minor(dev)); if (d->bd_bif == NULL) return (ENXIO); /* * Restrict application to use a buffer the same size as * as kernel buffers. */ if (uio->uio_resid != d->bd_bufsize) return (EINVAL); s = splnet(); D_GET(d); /* * If there's a timeout, bd_rdStart is tagged when we start the read. * we can then figure out when we're done reading. */ if (d->bd_rtout != -1 && d->bd_rdStart == 0) d->bd_rdStart = ticks; else d->bd_rdStart = 0; /* * If the hold buffer is empty, then do a timed sleep, which * ends when the timeout expires or when enough packets * have arrived to fill the store buffer. */ while (d->bd_hbuf == 0) { if (d->bd_bif == NULL) { /* interface is gone */ if (d->bd_slen == 0) { D_PUT(d); splx(s); return (EIO); } ROTATE_BUFFERS(d); break; } if (d->bd_immediate && d->bd_slen != 0) { /* * A packet(s) either arrived since the previous * read or arrived while we were asleep. * Rotate the buffers and return what's here. */ ROTATE_BUFFERS(d); break; } if (d->bd_rtout == -1) { /* User requested non-blocking I/O */ error = EWOULDBLOCK; } else { if ((d->bd_rdStart + d->bd_rtout) < ticks) { error = tsleep((caddr_t)d, PRINET|PCATCH, "bpf", d->bd_rtout); } else error = EWOULDBLOCK; } if (error == EINTR || error == ERESTART) { D_PUT(d); splx(s); return (error); } if (error == EWOULDBLOCK) { /* * On a timeout, return what's in the buffer, * which may be nothing. If there is something * in the store buffer, we can rotate the buffers. */ if (d->bd_hbuf) /* * We filled up the buffer in between * getting the timeout and arriving * here, so we don't need to rotate. */ break; if (d->bd_slen == 0) { D_PUT(d); splx(s); return (0); } ROTATE_BUFFERS(d); break; } } /* * At this point, we know we have something in the hold slot. */ splx(s); /* * Move data from hold buffer into user space. * We know the entire buffer is transferred since * we checked above that the read buffer is bpf_bufsize bytes. */ error = uiomove(d->bd_hbuf, d->bd_hlen, uio); s = splnet(); d->bd_fbuf = d->bd_hbuf; d->bd_hbuf = NULL; d->bd_hlen = 0; D_PUT(d); splx(s); return (error); } /* * If there are processes sleeping on this descriptor, wake them up. */ void bpf_wakeup(struct bpf_d *d) { wakeup((caddr_t)d); if (d->bd_async && d->bd_sig) csignal(d->bd_pgid, d->bd_sig, d->bd_siguid, d->bd_sigeuid); selwakeup(&d->bd_sel); /* XXX */ d->bd_sel.si_selpid = 0; } int bpfwrite(dev_t dev, struct uio *uio, int ioflag) { struct bpf_d *d; struct ifnet *ifp; struct mbuf *m; struct bpf_program *bf; struct bpf_insn *fcode = NULL; int error, s; struct sockaddr_storage dst; d = bpfilter_lookup(minor(dev)); if (d->bd_bif == NULL) return (ENXIO); ifp = d->bd_bif->bif_ifp; if ((ifp->if_flags & IFF_UP) == 0) return (ENETDOWN); if (uio->uio_resid == 0) return (0); KERNEL_ASSERT_LOCKED(); /* for accessing bd_wfilter */ bf = srp_get_locked(&d->bd_wfilter); if (bf != NULL) fcode = bf->bf_insns; error = bpf_movein(uio, d->bd_bif->bif_dlt, &m, (struct sockaddr *)&dst, fcode); if (error) return (error); if (m->m_pkthdr.len > ifp->if_mtu) { m_freem(m); return (EMSGSIZE); } m->m_pkthdr.ph_rtableid = ifp->if_rdomain; if (d->bd_hdrcmplt && dst.ss_family == AF_UNSPEC) dst.ss_family = pseudo_AF_HDRCMPLT; s = splsoftnet(); error = ifp->if_output(ifp, m, (struct sockaddr *)&dst, NULL); splx(s); /* * The driver frees the mbuf. */ return (error); } /* * Reset a descriptor by flushing its packet buffer and clearing the * receive and drop counts. Should be called at splnet. */ void bpf_reset_d(struct bpf_d *d) { if (d->bd_hbuf) { /* Free the hold buffer. */ d->bd_fbuf = d->bd_hbuf; d->bd_hbuf = NULL; } d->bd_slen = 0; d->bd_hlen = 0; d->bd_rcount = 0; d->bd_dcount = 0; } /* * FIONREAD Check for read packet available. * BIOCGBLEN Get buffer len [for read()]. * BIOCSETF Set ethernet read filter. * BIOCFLUSH Flush read packet buffer. * BIOCPROMISC Put interface into promiscuous mode. * BIOCGDLTLIST Get supported link layer types. * BIOCGDLT Get link layer type. * BIOCSDLT Set link layer type. * BIOCGETIF Get interface name. * BIOCSETIF Set interface. * BIOCSRTIMEOUT Set read timeout. * BIOCGRTIMEOUT Get read timeout. * BIOCGSTATS Get packet stats. * BIOCIMMEDIATE Set immediate mode. * BIOCVERSION Get filter language version. * BIOCGHDRCMPLT Get "header already complete" flag * BIOCSHDRCMPLT Set "header already complete" flag */ int bpfioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p) { struct bpf_d *d; int s, error = 0; d = bpfilter_lookup(minor(dev)); if (d->bd_locked && suser(p, 0) != 0) { /* list of allowed ioctls when locked and not root */ switch (cmd) { case BIOCGBLEN: case BIOCFLUSH: case BIOCGDLT: case BIOCGDLTLIST: case BIOCGETIF: case BIOCGRTIMEOUT: case BIOCGSTATS: case BIOCVERSION: case BIOCGRSIG: case BIOCGHDRCMPLT: case FIONREAD: case BIOCLOCK: case BIOCSRTIMEOUT: case BIOCIMMEDIATE: case TIOCGPGRP: case BIOCGDIRFILT: break; default: return (EPERM); } } switch (cmd) { default: error = EINVAL; break; /* * Check for read packet available. */ case FIONREAD: { int n; s = splnet(); n = d->bd_slen; if (d->bd_hbuf) n += d->bd_hlen; splx(s); *(int *)addr = n; break; } /* * Get buffer len [for read()]. */ case BIOCGBLEN: *(u_int *)addr = d->bd_bufsize; break; /* * Set buffer length. */ case BIOCSBLEN: if (d->bd_bif != NULL) error = EINVAL; else { u_int size = *(u_int *)addr; if (size > bpf_maxbufsize) *(u_int *)addr = size = bpf_maxbufsize; else if (size < BPF_MINBUFSIZE) *(u_int *)addr = size = BPF_MINBUFSIZE; d->bd_bufsize = size; } break; /* * Set link layer read filter. */ case BIOCSETF: error = bpf_setf(d, (struct bpf_program *)addr, 0); break; /* * Set link layer write filter. */ case BIOCSETWF: error = bpf_setf(d, (struct bpf_program *)addr, 1); break; /* * Flush read packet buffer. */ case BIOCFLUSH: s = splnet(); bpf_reset_d(d); splx(s); break; /* * Put interface into promiscuous mode. */ case BIOCPROMISC: if (d->bd_bif == NULL) { /* * No interface attached yet. */ error = EINVAL; break; } s = splnet(); if (d->bd_promisc == 0) { error = ifpromisc(d->bd_bif->bif_ifp, 1); if (error == 0) d->bd_promisc = 1; } splx(s); break; /* * Get a list of supported device parameters. */ case BIOCGDLTLIST: if (d->bd_bif == NULL) error = EINVAL; else error = bpf_getdltlist(d, (struct bpf_dltlist *)addr); break; /* * Get device parameters. */ case BIOCGDLT: if (d->bd_bif == NULL) error = EINVAL; else *(u_int *)addr = d->bd_bif->bif_dlt; break; /* * Set device parameters. */ case BIOCSDLT: if (d->bd_bif == NULL) error = EINVAL; else error = bpf_setdlt(d, *(u_int *)addr); break; /* * Set interface name. */ case BIOCGETIF: if (d->bd_bif == NULL) error = EINVAL; else bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr); break; /* * Set interface. */ case BIOCSETIF: error = bpf_setif(d, (struct ifreq *)addr); break; /* * Set read timeout. */ case BIOCSRTIMEOUT: { struct timeval *tv = (struct timeval *)addr; /* Compute number of ticks. */ d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; if (d->bd_rtout == 0 && tv->tv_usec != 0) d->bd_rtout = 1; break; } /* * Get read timeout. */ case BIOCGRTIMEOUT: { struct timeval *tv = (struct timeval *)addr; tv->tv_sec = d->bd_rtout / hz; tv->tv_usec = (d->bd_rtout % hz) * tick; break; } /* * Get packet stats. */ case BIOCGSTATS: { struct bpf_stat *bs = (struct bpf_stat *)addr; bs->bs_recv = d->bd_rcount; bs->bs_drop = d->bd_dcount; break; } /* * Set immediate mode. */ case BIOCIMMEDIATE: d->bd_immediate = *(u_int *)addr; break; case BIOCVERSION: { struct bpf_version *bv = (struct bpf_version *)addr; bv->bv_major = BPF_MAJOR_VERSION; bv->bv_minor = BPF_MINOR_VERSION; break; } case BIOCGHDRCMPLT: /* get "header already complete" flag */ *(u_int *)addr = d->bd_hdrcmplt; break; case BIOCSHDRCMPLT: /* set "header already complete" flag */ d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; break; case BIOCLOCK: /* set "locked" flag (no reset) */ d->bd_locked = 1; break; case BIOCGFILDROP: /* get "filter-drop" flag */ *(u_int *)addr = d->bd_fildrop; break; case BIOCSFILDROP: /* set "filter-drop" flag */ d->bd_fildrop = *(u_int *)addr ? 1 : 0; break; case BIOCGDIRFILT: /* get direction filter */ *(u_int *)addr = d->bd_dirfilt; break; case BIOCSDIRFILT: /* set direction filter */ d->bd_dirfilt = (*(u_int *)addr) & (BPF_DIRECTION_IN|BPF_DIRECTION_OUT); break; case FIONBIO: /* Non-blocking I/O */ if (*(int *)addr) d->bd_rtout = -1; else d->bd_rtout = 0; break; case FIOASYNC: /* Send signal on receive packets */ d->bd_async = *(int *)addr; break; /* * N.B. ioctl (FIOSETOWN) and fcntl (F_SETOWN) both end up doing * the equivalent of a TIOCSPGRP and hence end up here. *However* * TIOCSPGRP's arg is a process group if it's positive and a process * id if it's negative. This is exactly the opposite of what the * other two functions want! Therefore there is code in ioctl and * fcntl to negate the arg before calling here. */ case TIOCSPGRP: /* Process or group to send signals to */ d->bd_pgid = *(int *)addr; d->bd_siguid = p->p_ucred->cr_ruid; d->bd_sigeuid = p->p_ucred->cr_uid; break; case TIOCGPGRP: *(int *)addr = d->bd_pgid; break; case BIOCSRSIG: /* Set receive signal */ { u_int sig; sig = *(u_int *)addr; if (sig >= NSIG) error = EINVAL; else d->bd_sig = sig; break; } case BIOCGRSIG: *(u_int *)addr = d->bd_sig; break; } return (error); } /* * 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. */ int bpf_setf(struct bpf_d *d, struct bpf_program *fp, int wf) { struct bpf_program *bf; struct srp *filter; struct bpf_insn *fcode; u_int flen, size; int s; KERNEL_ASSERT_LOCKED(); filter = wf ? &d->bd_wfilter : &d->bd_rfilter; if (fp->bf_insns == 0) { if (fp->bf_len != 0) return (EINVAL); srp_update_locked(&bpf_insn_gc, filter, NULL); s = splnet(); bpf_reset_d(d); splx(s); return (0); } flen = fp->bf_len; if (flen > BPF_MAXINSNS) return (EINVAL); fcode = mallocarray(flen, sizeof(*fp->bf_insns), M_DEVBUF, M_WAITOK | M_CANFAIL); if (fcode == NULL) return (ENOMEM); size = flen * sizeof(*fp->bf_insns); if (copyin(fp->bf_insns, fcode, size) != 0 || bpf_validate(fcode, (int)flen) == 0) { free(fcode, M_DEVBUF, size); return (EINVAL); } bf = malloc(sizeof(*bf), M_DEVBUF, M_WAITOK); bf->bf_len = flen; bf->bf_insns = fcode; srp_update_locked(&bpf_insn_gc, filter, bf); s = splnet(); bpf_reset_d(d); splx(s); return (0); } /* * Detach a file from its current interface (if attached at all) and attach * to the interface indicated by the name stored in ifr. * Return an errno or 0. */ int bpf_setif(struct bpf_d *d, struct ifreq *ifr) { struct bpf_if *bp, *candidate = NULL; int s; /* * Look through attached interfaces for the named one. */ for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { struct ifnet *ifp = bp->bif_ifp; if (ifp == NULL || strcmp(ifp->if_xname, ifr->ifr_name) != 0) continue; if (candidate == NULL || candidate->bif_dlt > bp->bif_dlt) candidate = bp; } if (candidate != NULL) { /* * Allocate the packet buffers if we need to. * If we're already attached to requested interface, * just flush the buffer. */ if (d->bd_sbuf == NULL) bpf_allocbufs(d); s = splnet(); if (candidate != d->bd_bif) { if (d->bd_bif) /* * Detach if attached to something else. */ bpf_detachd(d); bpf_attachd(d, candidate); } bpf_reset_d(d); splx(s); return (0); } /* Not found. */ return (ENXIO); } /* * Copy the interface name to the ifreq. */ void bpf_ifname(struct ifnet *ifp, struct ifreq *ifr) { bcopy(ifp->if_xname, ifr->ifr_name, IFNAMSIZ); } /* * Support for poll() system call */ int bpfpoll(dev_t dev, int events, struct proc *p) { struct bpf_d *d; int s, revents; /* * An imitation of the FIONREAD ioctl code. */ d = bpfilter_lookup(minor(dev)); /* * XXX The USB stack manages it to trigger some race condition * which causes bpfilter_lookup to return NULL when a USB device * gets detached while it is up and has an open bpf handler (e.g. * dhclient). We still should recheck if we can fix the root * cause of this issue. */ if (d == NULL) return (POLLERR); /* Always ready to write data */ revents = events & (POLLOUT | POLLWRNORM); if (events & (POLLIN | POLLRDNORM)) { s = splnet(); if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) revents |= events & (POLLIN | POLLRDNORM); else { /* * if there's a timeout, mark the time we * started waiting. */ if (d->bd_rtout != -1 && d->bd_rdStart == 0) d->bd_rdStart = ticks; selrecord(p, &d->bd_sel); } splx(s); } return (revents); } struct filterops bpfread_filtops = { 1, NULL, filt_bpfrdetach, filt_bpfread }; int bpfkqfilter(dev_t dev, struct knote *kn) { struct bpf_d *d; struct klist *klist; int s; d = bpfilter_lookup(minor(dev)); switch (kn->kn_filter) { case EVFILT_READ: klist = &d->bd_sel.si_note; kn->kn_fop = &bpfread_filtops; break; default: return (EINVAL); } kn->kn_hook = d; s = splnet(); D_GET(d); SLIST_INSERT_HEAD(klist, kn, kn_selnext); if (d->bd_rtout != -1 && d->bd_rdStart == 0) d->bd_rdStart = ticks; splx(s); return (0); } void filt_bpfrdetach(struct knote *kn) { struct bpf_d *d = kn->kn_hook; int s; s = splnet(); SLIST_REMOVE(&d->bd_sel.si_note, kn, knote, kn_selnext); D_PUT(d); splx(s); } int filt_bpfread(struct knote *kn, long hint) { struct bpf_d *d = kn->kn_hook; kn->kn_data = d->bd_hlen; if (d->bd_immediate) kn->kn_data += d->bd_slen; return (kn->kn_data > 0); } /* * Incoming linkage from device drivers. Process the packet pkt, of length * pktlen, which is stored in a contiguous buffer. The packet is parsed * by each process' filter, and if accepted, stashed into the corresponding * buffer. */ int bpf_tap(caddr_t arg, u_char *pkt, u_int pktlen, u_int direction) { struct bpf_if *bp = (struct bpf_if *)arg; struct srpl_iter i; struct bpf_d *d; size_t slen; struct timeval tv; int drop = 0, gottime = 0; int s; if (bp == NULL) return (0); SRPL_FOREACH(d, &bp->bif_dlist, &i, bd_next) { atomic_inc_long(&d->bd_rcount); if ((direction & d->bd_dirfilt) != 0) slen = 0; else { struct bpf_program *bf; struct bpf_insn *fcode = NULL; bf = srp_enter(&d->bd_rfilter); if (bf != NULL) fcode = bf->bf_insns; slen = bpf_filter(fcode, pkt, pktlen, pktlen); srp_leave(&d->bd_rfilter, bf); } if (slen > 0) { if (!gottime++) microtime(&tv); KERNEL_LOCK(); s = splnet(); if (d->bd_bif != NULL) { bpf_catchpacket(d, pkt, pktlen, slen, bcopy, &tv); } splx(s); KERNEL_UNLOCK(); if (d->bd_fildrop) drop = 1; } } SRPL_LEAVE(&i, d); return (drop); } /* * Copy data from an mbuf chain into a buffer. This code is derived * from m_copydata in sys/uipc_mbuf.c. */ void bpf_mcopy(const void *src_arg, void *dst_arg, size_t len) { const struct mbuf *m; u_int count; u_char *dst; m = src_arg; dst = dst_arg; while (len > 0) { if (m == NULL) panic("bpf_mcopy"); count = min(m->m_len, len); bcopy(mtod(m, caddr_t), (caddr_t)dst, count); m = m->m_next; dst += count; len -= count; } } /* * like bpf_mtap, but copy fn can be given. used by various bpf_mtap* */ int _bpf_mtap(caddr_t arg, struct mbuf *m, u_int direction, void (*cpfn)(const void *, void *, size_t)) { struct bpf_if *bp = (struct bpf_if *)arg; struct srpl_iter i; struct bpf_d *d; size_t pktlen, slen; struct mbuf *m0; struct timeval tv; int gottime = 0; int drop = 0; int s; if (m == NULL) return (0); if (cpfn == NULL) cpfn = bpf_mcopy; if (bp == NULL) return (0); pktlen = 0; for (m0 = m; m0 != NULL; m0 = m0->m_next) pktlen += m0->m_len; SRPL_FOREACH(d, &bp->bif_dlist, &i, bd_next) { atomic_inc_long(&d->bd_rcount); if ((direction & d->bd_dirfilt) != 0) slen = 0; else { struct bpf_program *bf; struct bpf_insn *fcode = NULL; bf = srp_enter(&d->bd_rfilter); if (bf != NULL) fcode = bf->bf_insns; slen = bpf_mfilter(fcode, m, pktlen); srp_leave(&d->bd_rfilter, bf); } if (slen > 0) { if (!gottime++) microtime(&tv); KERNEL_LOCK(); s = splnet(); if (d->bd_bif != NULL) { bpf_catchpacket(d, (u_char *)m, pktlen, slen, cpfn, &tv); } splx(s); KERNEL_UNLOCK(); if (d->bd_fildrop) drop = 1; } } SRPL_LEAVE(&i, d); if (drop) m->m_flags |= M_FILDROP; return (drop); } /* * Incoming linkage from device drivers, when packet is in an mbuf chain. */ int bpf_mtap(caddr_t arg, struct mbuf *m, u_int direction) { return _bpf_mtap(arg, m, direction, NULL); } /* * Incoming linkage from device drivers, where we have a mbuf chain * but need to prepend some arbitrary header from a linear buffer. * * Con up a minimal dummy header to pacify bpf. Allocate (only) a * struct m_hdr on the stack. This is safe as bpf only reads from the * fields in this header that we initialize, and will not try to free * it or keep a pointer to it. */ int bpf_mtap_hdr(caddr_t arg, caddr_t data, u_int dlen, struct mbuf *m, u_int direction, void (*cpfn)(const void *, void *, size_t)) { struct m_hdr mh; struct mbuf *m0; int drop; if (dlen > 0) { mh.mh_flags = 0; mh.mh_next = m; mh.mh_len = dlen; mh.mh_data = data; m0 = (struct mbuf *)&mh; } else m0 = m; drop = _bpf_mtap(arg, m0, direction, cpfn); if (m0 != m) m->m_flags |= m0->m_flags & M_FILDROP; return (drop); } /* * Incoming linkage from device drivers, where we have a mbuf chain * but need to prepend the address family. * * Con up a minimal dummy header to pacify bpf. We allocate (only) a * struct m_hdr on the stack. This is safe as bpf only reads from the * fields in this header that we initialize, and will not try to free * it or keep a pointer to it. */ int bpf_mtap_af(caddr_t arg, u_int32_t af, struct mbuf *m, u_int direction) { u_int32_t afh; afh = htonl(af); return bpf_mtap_hdr(arg, (caddr_t)&afh, sizeof(afh), m, direction, NULL); } /* * Incoming linkage from device drivers, where we have a mbuf chain * but need to prepend a VLAN encapsulation header. * * Con up a minimal dummy header to pacify bpf. Allocate (only) a * struct m_hdr on the stack. This is safe as bpf only reads from the * fields in this header that we initialize, and will not try to free * it or keep a pointer to it. */ int bpf_mtap_ether(caddr_t arg, struct mbuf *m, u_int direction) { #if NVLAN > 0 struct ether_vlan_header evh; struct m_hdr mh; uint8_t prio; if ((m->m_flags & M_VLANTAG) == 0) #endif { return bpf_mtap(arg, m, direction); } #if NVLAN > 0 KASSERT(m->m_len >= ETHER_HDR_LEN); prio = m->m_pkthdr.pf.prio; if (prio <= 1) prio = !prio; memcpy(&evh, mtod(m, char *), ETHER_HDR_LEN); evh.evl_proto = evh.evl_encap_proto; evh.evl_encap_proto = htons(ETHERTYPE_VLAN); evh.evl_tag = htons(m->m_pkthdr.ether_vtag | (prio << EVL_PRIO_BITS)); mh.mh_flags = 0; mh.mh_data = m->m_data + ETHER_HDR_LEN; mh.mh_len = m->m_len - ETHER_HDR_LEN; mh.mh_next = m->m_next; return bpf_mtap_hdr(arg, (caddr_t)&evh, sizeof(evh), (struct mbuf *)&mh, direction, NULL); #endif } /* * Move the packet data from interface memory (pkt) into the * store buffer. Return 1 if it's time to wakeup a listener (buffer full), * otherwise 0. "copy" is the routine called to do the actual data * transfer. bcopy is passed in to copy contiguous chunks, while * bpf_mcopy is passed in to copy mbuf chains. In the latter case, * pkt is really an mbuf. */ void bpf_catchpacket(struct bpf_d *d, u_char *pkt, size_t pktlen, size_t snaplen, void (*cpfn)(const void *, void *, size_t), struct timeval *tv) { struct bpf_hdr *hp; int totlen, curlen; int hdrlen = d->bd_bif->bif_hdrlen; /* * Figure out how many bytes to move. If the packet is * greater or equal to the snapshot length, transfer that * much. Otherwise, transfer the whole packet (unless * we hit the buffer size limit). */ totlen = hdrlen + min(snaplen, pktlen); if (totlen > d->bd_bufsize) totlen = d->bd_bufsize; /* * Round up the end of the previous packet to the next longword. */ curlen = BPF_WORDALIGN(d->bd_slen); if (curlen + totlen > d->bd_bufsize) { /* * This packet will overflow the storage buffer. * Rotate the buffers if we can, then wakeup any * pending reads. */ if (d->bd_fbuf == NULL) { /* * We haven't completed the previous read yet, * so drop the packet. */ ++d->bd_dcount; return; } ROTATE_BUFFERS(d); bpf_wakeup(d); curlen = 0; } /* * Append the bpf header. */ hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); hp->bh_tstamp.tv_sec = tv->tv_sec; hp->bh_tstamp.tv_usec = tv->tv_usec; hp->bh_datalen = pktlen; hp->bh_hdrlen = hdrlen; /* * Copy the packet data into the store buffer and update its length. */ (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); d->bd_slen = curlen + totlen; if (d->bd_immediate) { /* * Immediate mode is set. A packet arrived so any * reads should be woken up. */ bpf_wakeup(d); } if (d->bd_rdStart && (d->bd_rtout + d->bd_rdStart < ticks)) { /* * we could be selecting on the bpf, and we * may have timeouts set. We got here by getting * a packet, so wake up the reader. */ if (d->bd_fbuf) { d->bd_rdStart = 0; ROTATE_BUFFERS(d); bpf_wakeup(d); } } } /* * Initialize all nonzero fields of a descriptor. */ void bpf_allocbufs(struct bpf_d *d) { d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); d->bd_slen = 0; d->bd_hlen = 0; } /* * Free buffers currently in use by a descriptor * when the reference count drops to zero. */ void bpf_freed(struct bpf_d *d) { if (--d->bd_ref > 0) return; free(d->bd_sbuf, M_DEVBUF, 0); free(d->bd_hbuf, M_DEVBUF, 0); free(d->bd_fbuf, M_DEVBUF, 0); KERNEL_ASSERT_LOCKED(); srp_update_locked(&bpf_insn_gc, &d->bd_rfilter, NULL); srp_update_locked(&bpf_insn_gc, &d->bd_wfilter, NULL); bpfilter_destroy(d); } /* * Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *) * in the driver's softc; dlt is the link layer type; hdrlen is the fixed * size of the link header (variable length headers not yet supported). */ void bpfattach(caddr_t *driverp, struct ifnet *ifp, u_int dlt, u_int hdrlen) { struct bpf_if *bp; if ((bp = malloc(sizeof(*bp), M_DEVBUF, M_NOWAIT)) == NULL) panic("bpfattach"); SRPL_INIT(&bp->bif_dlist); bp->bif_driverp = (struct bpf_if **)driverp; bp->bif_ifp = ifp; bp->bif_dlt = dlt; bp->bif_next = bpf_iflist; bpf_iflist = bp; *bp->bif_driverp = NULL; /* * Compute the length of the bpf header. This is not necessarily * equal to SIZEOF_BPF_HDR because we want to insert spacing such * that the network layer header begins on a longword boundary (for * performance reasons and to alleviate alignment restrictions). */ bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; } /* Detach an interface from its attached bpf device. */ void bpfdetach(struct ifnet *ifp) { struct bpf_if *bp, *nbp, **pbp = &bpf_iflist; struct bpf_d *bd; int maj; KERNEL_ASSERT_LOCKED(); for (bp = bpf_iflist; bp; bp = nbp) { nbp= bp->bif_next; if (bp->bif_ifp == ifp) { *pbp = nbp; /* Locate the major number. */ for (maj = 0; maj < nchrdev; maj++) if (cdevsw[maj].d_open == bpfopen) break; while ((bd = SRPL_FIRST_LOCKED(&bp->bif_dlist))) { struct bpf_d *d; /* * Locate the minor number and nuke the vnode * for any open instance. */ LIST_FOREACH(d, &bpf_d_list, bd_list) if (d == bd) { vdevgone(maj, d->bd_unit, d->bd_unit, VCHR); break; } } free(bp, M_DEVBUF, sizeof *bp); } else pbp = &bp->bif_next; } ifp->if_bpf = NULL; } int bpf_sysctl_locked(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { int newval; int error; switch (name[0]) { case NET_BPF_BUFSIZE: newval = bpf_bufsize; error = sysctl_int(oldp, oldlenp, newp, newlen, &newval); if (error) return (error); if (newval < BPF_MINBUFSIZE || newval > bpf_maxbufsize) return (EINVAL); bpf_bufsize = newval; break; case NET_BPF_MAXBUFSIZE: newval = bpf_maxbufsize; error = sysctl_int(oldp, oldlenp, newp, newlen, &newval); if (error) return (error); if (newval < BPF_MINBUFSIZE) return (EINVAL); bpf_maxbufsize = newval; break; default: return (EOPNOTSUPP); } return (0); } int bpf_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { static struct rwlock bpf_sysctl_lk = RWLOCK_INITIALIZER("bpfsz"); int flags = RW_INTR; int error; if (namelen != 1) return (ENOTDIR); flags |= (newp == NULL) ? RW_READ : RW_WRITE; error = rw_enter(&bpf_sysctl_lk, flags); if (error != 0) return (error); error = bpf_sysctl_locked(name, namelen, oldp, oldlenp, newp, newlen); rw_exit(&bpf_sysctl_lk); return (error); } struct bpf_d * bpfilter_lookup(int unit) { struct bpf_d *bd; LIST_FOREACH(bd, &bpf_d_list, bd_list) if (bd->bd_unit == unit) return (bd); return (NULL); } struct bpf_d * bpfilter_create(int unit) { struct bpf_d *bd; if ((bd = bpfilter_lookup(unit)) != NULL) return (NULL); if ((bd = malloc(sizeof(*bd), M_DEVBUF, M_NOWAIT|M_ZERO)) != NULL) { bd->bd_unit = unit; LIST_INSERT_HEAD(&bpf_d_list, bd, bd_list); } return (bd); } void bpfilter_destroy(struct bpf_d *bd) { LIST_REMOVE(bd, bd_list); free(bd, M_DEVBUF, sizeof(*bd)); } /* * Get a list of available data link type of the interface. */ int bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) { int n, error; struct ifnet *ifp; struct bpf_if *bp; ifp = d->bd_bif->bif_ifp; n = 0; error = 0; for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { if (bp->bif_ifp != ifp) continue; if (bfl->bfl_list != NULL) { if (n >= bfl->bfl_len) return (ENOMEM); error = copyout(&bp->bif_dlt, bfl->bfl_list + n, sizeof(u_int)); if (error) break; } n++; } bfl->bfl_len = n; return (error); } /* * Set the data link type of a BPF instance. */ int bpf_setdlt(struct bpf_d *d, u_int dlt) { int s; struct ifnet *ifp; struct bpf_if *bp; if (d->bd_bif->bif_dlt == dlt) return (0); ifp = d->bd_bif->bif_ifp; for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) break; } if (bp == NULL) return (EINVAL); s = splnet(); bpf_detachd(d); bpf_attachd(d, bp); bpf_reset_d(d); splx(s); return (0); } void bpf_d_ref(void *null, void *d) { D_GET((struct bpf_d *)d); } void bpf_d_unref(void *null, void *d) { D_PUT(d); } void bpf_insn_dtor(void *null, void *f) { struct bpf_program *bf = f; struct bpf_insn *insns = bf->bf_insns; free(insns, M_DEVBUF, bf->bf_len * sizeof(*insns)); free(bf, M_DEVBUF, sizeof(*bf)); } u_int32_t bpf_mbuf_ldw(const void *, u_int32_t, int *); u_int32_t bpf_mbuf_ldh(const void *, u_int32_t, int *); u_int32_t bpf_mbuf_ldb(const void *, u_int32_t, int *); int bpf_mbuf_copy(const struct mbuf *, u_int32_t, void *, u_int32_t); const struct bpf_ops bpf_mbuf_ops = { bpf_mbuf_ldw, bpf_mbuf_ldh, bpf_mbuf_ldb, }; int bpf_mbuf_copy(const struct mbuf *m, u_int32_t off, void *buf, u_int32_t len) { u_int8_t *cp = buf; u_int32_t count; while (off >= m->m_len) { off -= m->m_len; m = m->m_next; if (m == NULL) return (-1); } for (;;) { count = min(m->m_len - off, len); memcpy(cp, m->m_data + off, count); len -= count; if (len == 0) return (0); m = m->m_next; if (m == NULL) break; cp += count; off = 0; } return (-1); } u_int32_t bpf_mbuf_ldw(const void *m0, u_int32_t k, int *err) { u_int32_t v; if (bpf_mbuf_copy(m0, k, &v, sizeof(v)) != 0) { *err = 1; return (0); } *err = 0; return ntohl(v); } u_int32_t bpf_mbuf_ldh(const void *m0, u_int32_t k, int *err) { u_int16_t v; if (bpf_mbuf_copy(m0, k, &v, sizeof(v)) != 0) { *err = 1; return (0); } *err = 0; return ntohs(v); } u_int32_t bpf_mbuf_ldb(const void *m0, u_int32_t k, int *err) { const struct mbuf *m = m0; while (k >= m->m_len) { k -= m->m_len; m = m->m_next; if (m == NULL) { *err = 1; return (0); } } *err = 0; return (m->m_data[k]); } u_int bpf_mfilter(const struct bpf_insn *pc, const struct mbuf *m, u_int wirelen) { return _bpf_filter(pc, &bpf_mbuf_ops, m, wirelen); }