/* $OpenBSD: bpf.c,v 1.33 2002/06/06 21:34:16 provos 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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 #define BPF_BUFSIZE 8192 /* 4096 too small for FDDI frames */ #define PRINET 26 /* interruptible */ /* * The default read buffer size is patchable. */ int bpf_bufsize = BPF_BUFSIZE; /* * bpf_iflist is the list of interfaces; each corresponds to an ifnet * bpf_dtab holds the descriptors, indexed by minor device # */ struct bpf_if *bpf_iflist; struct bpf_d *bpf_dtab; int nbpfilter; 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 *); void bpf_attachd(struct bpf_d *, struct bpf_if *); void bpf_detachd(struct bpf_d *); int bpf_setif(struct bpf_d *, struct ifreq *); int bpfselect(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); int bpf_movein(uio, linktype, mp, sockp) register struct uio *uio; int linktype; register struct mbuf **mp; register struct sockaddr *sockp; { struct mbuf *m; int error; int len; int hlen; /* * 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 = sizeof(struct ether_header); 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; default: return (EIO); } len = uio->uio_resid; if ((unsigned)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; /* * Make room for link header. */ if (hlen != 0) { m->m_len -= hlen; m->m_data += hlen; /* XXX */ error = uiomove((caddr_t)sockp->sa_data, hlen, uio); if (error) goto bad; } error = uiomove(mtod(m, caddr_t), len - hlen, uio); if (!error) 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(d, bp) 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(d) 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) /* * bpfilterattach() is called at boot time in new systems. We do * nothing here since old systems will not call this. */ /* ARGSUSED */ void bpfilterattach(n) int n; { int i; bpf_dtab = malloc(n * sizeof(*bpf_dtab), M_DEVBUF, M_NOWAIT); if (!bpf_dtab) return; nbpfilter = n; bzero(bpf_dtab, n * sizeof(*bpf_dtab)); /* * Mark all the descriptors free if this hasn't been done. */ if (!D_ISFREE(&bpf_dtab[0])) for (i = 0; i < nbpfilter; ++i) D_MARKFREE(&bpf_dtab[i]); } /* * Open ethernet device. Returns ENXIO for illegal minor device number, * EBUSY if file is open by another process. */ /* ARGSUSED */ int bpfopen(dev, flag, mode, p) dev_t dev; int flag; int mode; struct proc *p; { register struct bpf_d *d; if (minor(dev) >= nbpfilter) return (ENXIO); /* * Each minor can be opened by only one process. If the requested * minor is in use, return EBUSY. */ d = &bpf_dtab[minor(dev)]; if (!D_ISFREE(d)) return (EBUSY); /* Mark "free" and do most initialization. */ bzero((char *)d, sizeof(*d)); d->bd_bufsize = bpf_bufsize; d->bd_sig = SIGIO; return (0); } /* * Close the descriptor by detaching it from its interface, * deallocating its buffers, and marking it free. */ /* ARGSUSED */ int bpfclose(dev, flag, mode, p) dev_t dev; int flag; int mode; struct proc *p; { register struct bpf_d *d = &bpf_dtab[minor(dev)]; register int s; s = splimp(); if (d->bd_bif) bpf_detachd(d); splx(s); bpf_freed(d); 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, uio, ioflag) dev_t dev; register struct uio *uio; int ioflag; { register struct bpf_d *d = &bpf_dtab[minor(dev)]; int error; int s; 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(); /* * 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_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) { 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) { 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; splx(s); return (error); } /* * If there are processes sleeping on this descriptor, wake them up. */ static __inline void bpf_wakeup(d) register 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, uio, ioflag) dev_t dev; struct uio *uio; int ioflag; { register struct bpf_d *d = &bpf_dtab[minor(dev)]; struct ifnet *ifp; struct mbuf *m; int error, s; struct sockaddr dst; if (d->bd_bif == 0) return (ENXIO); ifp = d->bd_bif->bif_ifp; if (uio->uio_resid == 0) return (0); error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst); if (error) return (error); if (m->m_pkthdr.len > ifp->if_mtu) { m_freem(m); return (EMSGSIZE); } if (d->bd_hdrcmplt) dst.sa_family = pseudo_AF_HDRCMPLT; s = splsoftnet(); error = (*ifp->if_output)(ifp, m, &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(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, cmd, addr, flag, p) dev_t dev; u_long cmd; caddr_t addr; int flag; struct proc *p; { register struct bpf_d *d = &bpf_dtab[minor(dev)]; int s, error = 0; 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 { register 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); 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 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(d, fp) struct bpf_d *d; struct bpf_program *fp; { struct bpf_insn *fcode, *old; u_int flen, size; int s; old = d->bd_filter; if (fp->bf_insns == 0) { if (fp->bf_len != 0) return (EINVAL); s = splimp(); d->bd_filter = 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(); d->bd_filter = 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(d, ifr) struct bpf_d *d; struct ifreq *ifr; { struct bpf_if *bp; char *cp; int unit_seen, i, s, error; /* * Make sure the provided name has a unit number, and default * it to '0' if not specified. * XXX This is ugly ... do this differently? */ unit_seen = 0; cp = ifr->ifr_name; cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */ while (*cp++) if (*cp >= '0' && *cp <= '9') unit_seen = 1; if (!unit_seen) { /* Make sure to leave room for the '\0'. */ for (i = 0; i < (IFNAMSIZ - 1); ++i) { if ((ifr->ifr_name[i] >= 'a' && ifr->ifr_name[i] <= 'z') || (ifr->ifr_name[i] >= 'A' && ifr->ifr_name[i] <= 'Z')) continue; ifr->ifr_name[i] = '0'; } } /* * 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 it's not up, return an error. * Allocate the packet buffers if we need to. * If we're already attached to requested interface, * just flush the buffer. */ if ((ifp->if_flags & IFF_UP) == 0) return (ENETDOWN); if (d->bd_sbuf == 0) { error = bpf_allocbufs(d); if (error != 0) return (error); } s = splimp(); if (bp != d->bd_bif) { if (d->bd_bif) /* * Detach if attached to something else. */ bpf_detachd(d); bpf_attachd(d, bp); } bpf_reset_d(d); splx(s); return (0); } /* Not found. */ return (ENXIO); } /* * Copy the interface name to the ifreq. */ void bpf_ifname(ifp, ifr) struct ifnet *ifp; struct ifreq *ifr; { bcopy(ifp->if_xname, ifr->ifr_name, IFNAMSIZ); } /* * Support for select() system call * * Return true iff the specific operation will not block indefinitely. * Otherwise, return false but make a note that a selwakeup() must be done. */ int bpfselect(dev, rw, p) register dev_t dev; int rw; struct proc *p; { register struct bpf_d *d; register int s; if (rw != FREAD) return (0); /* * An imitation of the FIONREAD ioctl code. */ d = &bpf_dtab[minor(dev)]; s = splimp(); if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) { /* * There is data waiting. */ splx(s); return (1); } /* * if there isn't data waiting, and 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 (0); } struct filterops bpfread_filtops = { 1, NULL, filt_bpfrdetach, filt_bpfread }; int bpfkqfilter(dev_t dev,struct knote *kn) { struct bpf_d *d = &bpf_dtab[minor(dev)]; struct klist *klist; int s; switch (kn->kn_filter) { case EVFILT_READ: klist = &d->bd_sel.si_note; kn->kn_fop = &bpfread_filtops; break; case EVFILT_WRITE: 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 = &bpf_dtab[minor(dev)]; int 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 = &bpf_dtab[minor(dev)]; int res, s; kn->kn_data = 0; s = splimp(); res = d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0); splx(s); return (res); } /* * 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. */ void bpf_tap(arg, pkt, pktlen) caddr_t arg; register u_char *pkt; register u_int pktlen; { struct bpf_if *bp; register struct bpf_d *d; register size_t slen; /* * 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_filter, pkt, pktlen, pktlen); if (slen != 0) bpf_catchpacket(d, pkt, pktlen, slen, bcopy); } } /* * Copy data from an mbuf chain into a buffer. This code is derived * from m_copydata in sys/uipc_mbuf.c. */ void bpf_mcopy(src_arg, dst_arg, len) const void *src_arg; void *dst_arg; register size_t len; { register const struct mbuf *m; register 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. */ void bpf_mtap(arg, m) 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; if (m == NULL) return; 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_filter, (u_char *)m, pktlen, 0); if (slen != 0) bpf_catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); } } /* * 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(d, pkt, pktlen, snaplen, cpfn) register struct bpf_d *d; register u_char *pkt; register size_t pktlen, snaplen; register void (*cpfn)(const void *, void *, size_t); { register struct bpf_hdr *hp; register int totlen, curlen; register 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; } else if (d->bd_immediate) { /* * Immediate mode is set. A packet arrived so any * reads should be woken up. */ bpf_wakeup(d); } /* * 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_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(d) register struct bpf_d *d; { d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); d->bd_slen = 0; d->bd_hlen = 0; return (0); } /* * Free buffers currently in use by a descriptor. * Called on close. */ void bpf_freed(d) register struct bpf_d *d; { /* * 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. */ 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_filter) free((caddr_t)d->bd_filter, M_DEVBUF); D_MARKFREE(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(driverp, ifp, dlt, hdrlen) caddr_t *driverp; struct ifnet *ifp; u_int dlt, 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(ifp) struct ifnet *ifp; { struct bpf_if *bp, *nbp, **pbp = &bpf_iflist; struct bpf_d *bd; int maj, mn; 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) /* * Locate the minor number and nuke the vnode * for any open instance. */ for (mn = 0; mn < nbpfilter; mn++) if (&bpf_dtab[mn] == bd) { vdevgone(maj, mn, mn, VCHR); break; } free(bp, M_DEVBUF); } else pbp = &bp->bif_next; } ifp->if_bpf = NULL; }