/* $OpenBSD: bpf.c,v 1.55 2004/12/17 15:56:58 reyk 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. * * 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 #define BPF_BUFSIZE 32768 #define PRINET 26 /* interruptible */ /* * 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; int bpf_allocbufs(struct bpf_d *); void bpf_freed(struct bpf_d *); void bpf_ifname(struct ifnet *, struct ifreq *); void bpf_mcopy(const void *, void *, size_t); int bpf_movein(struct uio *, 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 *); static __inline void bpf_wakeup(struct bpf_d *); void bpf_catchpacket(struct bpf_d *, u_char *, size_t, size_t, void (*)(const void *, void *, size_t)); void bpf_reset_d(struct bpf_d *); void filt_bpfrdetach(struct knote *); int filt_bpfread(struct knote *, long); struct bpf_d *bpfilter_lookup(int); struct bpf_d *bpfilter_create(int); void bpfilter_destroy(struct bpf_d *); int bpf_movein(struct uio *uio, int linktype, struct mbuf **mp, struct sockaddr *sockp, struct bpf_insn *filter) { struct mbuf *m; 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_ARCNET: sockp->sa_family = AF_UNSPEC; hlen = ARC_HDRLEN; break; case DLT_FDDI: sockp->sa_family = AF_UNSPEC; /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */ hlen = 24; break; case DLT_RAW: case DLT_NULL: sockp->sa_family = AF_UNSPEC; hlen = 0; break; case DLT_ATM_RFC1483: /* * en atm driver requires 4-byte atm pseudo header. * though it isn't standard, vpi:vci needs to be * specified anyway. */ sockp->sa_family = AF_UNSPEC; hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */ break; default: return (EIO); } len = uio->uio_resid; if (len > MCLBYTES) return (EIO); MGETHDR(m, M_WAIT, MT_DATA); m->m_pkthdr.rcvif = 0; m->m_pkthdr.len = len - hlen; if (len > MHLEN) { MCLGET(m, M_WAIT); 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) { bcopy(m->m_data, sockp->sa_data, hlen); m->m_len -= hlen; m->m_data += hlen; /* XXX */ } 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 splimp. */ 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; d->bd_next = bp->bif_dlist; bp->bif_dlist = d; *bp->bif_driverp = bp; } /* * Detach a file from its interface. */ void bpf_detachd(struct bpf_d *d) { struct bpf_d **p; 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. */ p = &bp->bif_dlist; while (*p != d) { p = &(*p)->bd_next; if (*p == 0) panic("bpf_detachd: descriptor not in list"); } *p = (*p)->bd_next; if (bp->bif_dlist == 0) /* * Let the driver know that there are no more listeners. */ *d->bd_bif->bif_driverp = 0; d->bd_bif = 0; } /* * Mark a descriptor free by making it point to itself. * This is probably cheaper than marking with a constant since * the address should be in a register anyway. */ #define D_ISFREE(d) ((d) == (d)->bd_next) #define D_MARKFREE(d) ((d)->bd_next = (d)) #define D_MARKUSED(d) ((d)->bd_next = 0) /* * Reference count access to descriptor buffers */ #define D_GET(d) ((d)->bd_ref++) #define D_PUT(d) bpf_freed(d) /* * bpfilterattach() is called at boot time in new systems. We do * nothing here since old systems will not call this. */ /* ARGSUSED */ 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. */ /* ARGSUSED */ 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 (ENXIO); /* * Each minor can be opened by only one process. If the requested * minor is in use, return EBUSY. */ if (!D_ISFREE(d)) return (EBUSY); /* Mark "free" and do most initialization. */ d->bd_bufsize = bpf_bufsize; d->bd_sig = SIGIO; D_GET(d); return (0); } /* * Close the descriptor by detaching it from its interface, * deallocating its buffers, and marking it free. */ /* ARGSUSED */ int bpfclose(dev_t dev, int flag, int mode, struct proc *p) { struct bpf_d *d; int s; d = bpfilter_lookup(minor(dev)); s = splimp(); 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 == 0) 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 = splimp(); D_GET(d); /* * bd_rdStart is tagged when we start the read, iff there's a timeout. * 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) || (d->bd_rdStart + d->bd_rtout) < ticks) { error = tsleep((caddr_t)d, PRINET|PCATCH, "bpf", d->bd_rtout); } else { if (d->bd_rtout == -1) { /* User requested non-blocking I/O */ error = EWOULDBLOCK; } else error = 0; } 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 = splimp(); d->bd_fbuf = d->bd_hbuf; d->bd_hbuf = 0; d->bd_hlen = 0; D_PUT(d); splx(s); return (error); } /* * If there are processes sleeping on this descriptor, wake them up. */ static __inline 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; KNOTE(&d->bd_sel.si_note, 0); } int bpfwrite(dev_t dev, struct uio *uio, int ioflag) { struct bpf_d *d; struct ifnet *ifp; struct mbuf *m; int error, s; struct sockaddr_storage dst; d = bpfilter_lookup(minor(dev)); if (d->bd_bif == 0) return (ENXIO); ifp = d->bd_bif->bif_ifp; if ((ifp->if_flags & IFF_UP) == 0) return (ENETDOWN); if (uio->uio_resid == 0) return (0); error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, (struct sockaddr *)&dst, d->bd_wfilter); if (error) return (error); if (m->m_pkthdr.len > ifp->if_mtu) { m_freem(m); return (EMSGSIZE); } if (d->bd_hdrcmplt) dst.ss_family = pseudo_AF_HDRCMPLT; s = splsoftnet(); error = (*ifp->if_output)(ifp, m, (struct sockaddr *)&dst, (struct rtentry *)0); 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 splimp. */ 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 = 0; } 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. * BIOCGDLT Get 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 */ /* ARGSUSED */ 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 BIOCGETIF: case BIOCGRTIMEOUT: case BIOCGSTATS: case BIOCVERSION: case BIOCGRSIG: case BIOCGHDRCMPLT: case FIONREAD: case BIOCLOCK: case BIOCSRTIMEOUT: case BIOCIMMEDIATE: case TIOCGPGRP: break; default: return (EPERM); } } switch (cmd) { default: error = EINVAL; break; /* * Check for read packet available. */ case FIONREAD: { int n; s = splimp(); 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 != 0) 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 = splimp(); bpf_reset_d(d); splx(s); break; /* * Put interface into promiscuous mode. */ case BIOCPROMISC: if (d->bd_bif == 0) { /* * No interface attached yet. */ error = EINVAL; break; } s = splimp(); if (d->bd_promisc == 0) { error = ifpromisc(d->bd_bif->bif_ifp, 1); if (error == 0) d->bd_promisc = 1; } splx(s); break; /* * Get device parameters. */ case BIOCGDLT: if (d->bd_bif == 0) error = EINVAL; else *(u_int *)addr = d->bd_bif->bif_dlt; break; /* * Set interface name. */ case BIOCGETIF: if (d->bd_bif == 0) 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 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_cred->p_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_insn *fcode, *old; u_int flen, size; int s; old = wf ? d->bd_wfilter : d->bd_rfilter; if (fp->bf_insns == 0) { if (fp->bf_len != 0) return (EINVAL); s = splimp(); if (wf) d->bd_wfilter = 0; else d->bd_rfilter = 0; bpf_reset_d(d); splx(s); if (old != 0) free((caddr_t)old, M_DEVBUF); return (0); } flen = fp->bf_len; if (flen > BPF_MAXINSNS) return (EINVAL); size = flen * sizeof(*fp->bf_insns); fcode = (struct bpf_insn *)malloc(size, M_DEVBUF, M_WAITOK); if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && bpf_validate(fcode, (int)flen)) { s = splimp(); if (wf) d->bd_wfilter = fcode; else d->bd_rfilter = fcode; bpf_reset_d(d); splx(s); if (old != 0) free((caddr_t)old, M_DEVBUF); return (0); } free((caddr_t)fcode, M_DEVBUF); return (EINVAL); } /* * 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, error; /* * Look through attached interfaces for the named one. */ for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { struct ifnet *ifp = bp->bif_ifp; if (ifp == 0 || strcmp(ifp->if_xname, ifr->ifr_name) != 0) continue; /* * We found the requested interface. */ 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 == 0) { error = bpf_allocbufs(d); if (error != 0) return (error); } s = splimp(); 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; revents = events & (POLLIN | POLLRDNORM); if (revents == 0) return (0); /* only support reading */ /* * An imitation of the FIONREAD ioctl code. */ d = bpfilter_lookup(minor(dev)); s = splimp(); if (d->bd_hlen == 0 && (!d->bd_immediate || d->bd_slen == 0)) { revents = 0; /* no data waiting */ /* * 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 (1); } kn->kn_hook = (caddr_t)((u_long)dev); s = splimp(); SLIST_INSERT_HEAD(klist, kn, kn_selnext); splx(s); return (0); } void filt_bpfrdetach(struct knote *kn) { dev_t dev = (dev_t)((u_long)kn->kn_hook); struct bpf_d *d; int s; d = bpfilter_lookup(minor(dev)); s = splimp(); SLIST_REMOVE(&d->bd_sel.si_note, kn, knote, kn_selnext); splx(s); } int filt_bpfread(struct knote *kn, long hint) { dev_t dev = (dev_t)((u_long)kn->kn_hook); struct bpf_d *d; d = bpfilter_lookup(minor(dev)); 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) { struct bpf_if *bp; struct bpf_d *d; size_t slen; int drop = 0; /* * Note that the ipl does not have to be raised at this point. * The only problem that could arise here is that if two different * interfaces shared any data. This is not the case. */ bp = (struct bpf_if *)arg; for (d = bp->bif_dlist; d != 0; d = d->bd_next) { ++d->bd_rcount; slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen); if (slen != 0) { bpf_catchpacket(d, pkt, pktlen, slen, bcopy); if (d->bd_fildrop) drop++; } } 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 == 0) 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; } } /* * Incoming linkage from device drivers, when packet is in an mbuf chain. */ int bpf_mtap(caddr_t arg, struct mbuf *m) { struct bpf_if *bp = (struct bpf_if *)arg; struct bpf_d *d; size_t pktlen, slen; struct mbuf *m0; int drop = 0; if (m == NULL) return (0); pktlen = 0; for (m0 = m; m0 != 0; m0 = m0->m_next) pktlen += m0->m_len; for (d = bp->bif_dlist; d != 0; d = d->bd_next) { ++d->bd_rcount; slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0); if (slen == 0) continue; bpf_catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); if (d->bd_fildrop) drop++; } return (drop); } /* * 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 bpf_hdr *hp; int totlen, curlen; int hdrlen = d->bd_bif->bif_hdrlen; struct timeval tv; /* * 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 == 0) { /* * 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); microtime(&tv); 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); curlen = 0; } } } /* * Initialize all nonzero fields of a descriptor. */ int bpf_allocbufs(struct bpf_d *d) { d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT); if (d->bd_fbuf == NULL) return (ENOBUFS); d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT); if (d->bd_sbuf == NULL) { free(d->bd_fbuf, M_DEVBUF); return (ENOBUFS); } d->bd_slen = 0; d->bd_hlen = 0; return (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; if (d->bd_sbuf != 0) { free(d->bd_sbuf, M_DEVBUF); if (d->bd_hbuf != 0) free(d->bd_hbuf, M_DEVBUF); if (d->bd_fbuf != 0) free(d->bd_fbuf, M_DEVBUF); } if (d->bd_rfilter) free((caddr_t)d->bd_rfilter, M_DEVBUF); if (d->bd_wfilter) free((caddr_t)d->bd_wfilter, M_DEVBUF); 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; bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); if (bp == 0) panic("bpfattach"); bp->bif_dlist = 0; 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 = 0; /* * 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; 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; for (bd = bp->bif_dlist; bd; bd = 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); } else pbp = &bp->bif_next; } ifp->if_bpf = NULL; } int bpf_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { int newval; int error; if (namelen != 1) return (ENOTDIR); 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); } 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 (bd); if ((bd = malloc(sizeof(*bd), M_DEVBUF, M_NOWAIT)) != NULL) { bzero(bd, sizeof(*bd)); bd->bd_unit = unit; D_MARKFREE(bd); 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); }