/* * 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 8.4 (Berkeley) 1/9/95 * * $FreeBSD$ */ #include "opt_bpf.h" #include "opt_mac.h" #include "opt_netgraph.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_BPF, "BPF", "BPF data"); #if defined(DEV_BPF) || defined(NETGRAPH_BPF) #define PRINET 26 /* interruptible */ /* * The default read buffer size is patchable. */ static int bpf_bufsize = 4096; SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW, &bpf_bufsize, 0, ""); static int bpf_maxbufsize = BPF_MAXBUFSIZE; SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW, &bpf_maxbufsize, 0, ""); /* * bpf_iflist is the list of interfaces; each corresponds to an ifnet */ static struct bpf_if *bpf_iflist; static struct mtx bpf_mtx; /* bpf global lock */ static int bpf_allocbufs(struct bpf_d *); static void bpf_attachd(struct bpf_d *d, struct bpf_if *bp); static void bpf_detachd(struct bpf_d *d); static void bpf_freed(struct bpf_d *); static void bpf_mcopy(const void *, void *, size_t); static int bpf_movein(struct uio *, int, struct mbuf **, struct sockaddr *, int *); static int bpf_setif(struct bpf_d *, struct ifreq *); static void bpf_timed_out(void *); static __inline void bpf_wakeup(struct bpf_d *); static void catchpacket(struct bpf_d *, u_char *, u_int, u_int, void (*)(const void *, void *, size_t)); static void reset_d(struct bpf_d *); static int bpf_setf(struct bpf_d *, struct bpf_program *); static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); static int bpf_setdlt(struct bpf_d *, u_int); static d_open_t bpfopen; static d_close_t bpfclose; static d_read_t bpfread; static d_write_t bpfwrite; static d_ioctl_t bpfioctl; static d_poll_t bpfpoll; #define CDEV_MAJOR 23 static struct cdevsw bpf_cdevsw = { .d_open = bpfopen, .d_close = bpfclose, .d_read = bpfread, .d_write = bpfwrite, .d_ioctl = bpfioctl, .d_poll = bpfpoll, .d_name = "bpf", .d_maj = CDEV_MAJOR, }; static int bpf_movein(uio, linktype, mp, sockp, datlen) struct uio *uio; int linktype, *datlen; struct mbuf **mp; 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_EN10MB: sockp->sa_family = AF_UNSPEC; /* XXX Would MAXLINKHDR be better? */ hlen = ETHER_HDR_LEN; break; case DLT_FDDI: sockp->sa_family = AF_IMPLINK; hlen = 0; 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; case DLT_PPP: sockp->sa_family = AF_UNSPEC; hlen = 4; /* This should match PPP_HDRLEN */ break; default: return (EIO); } len = uio->uio_resid; *datlen = len - hlen; if ((unsigned)len > MCLBYTES) return (EIO); if (len > MHLEN) { m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR); } else { MGETHDR(m, M_TRYWAIT, MT_DATA); } if (m == NULL) return (ENOBUFS); m->m_pkthdr.len = m->m_len = len; m->m_pkthdr.rcvif = NULL; *mp = m; /* * Make room for link header. */ if (hlen != 0) { m->m_pkthdr.len -= hlen; m->m_len -= hlen; #if BSD >= 199103 m->m_data += hlen; /* XXX */ #else m->m_off += hlen; #endif error = uiomove(sockp->sa_data, hlen, uio); if (error) goto bad; } error = uiomove(mtod(m, void *), 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. */ static 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. */ BPFIF_LOCK(bp); d->bd_bif = bp; d->bd_next = bp->bif_dlist; bp->bif_dlist = d; *bp->bif_driverp = bp; BPFIF_UNLOCK(bp); } /* * Detach a file from its interface. */ static void bpf_detachd(d) struct bpf_d *d; { int error; 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) { d->bd_promisc = 0; error = ifpromisc(bp->bif_ifp, 0); if (error != 0 && error != ENXIO) { /* * ENXIO can happen if a pccard is unplugged * Something is really wrong if we were able to put * the driver into promiscuous mode, but can't * take it out. */ if_printf(bp->bif_ifp, "bpf_detach: ifpromisc failed (%d)\n", error); } } /* Remove d from the interface's descriptor list. */ BPFIF_LOCK(bp); 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; BPFIF_UNLOCK(bp); d->bd_bif = 0; } /* * Open ethernet device. Returns ENXIO for illegal minor device number, * EBUSY if file is open by another process. */ /* ARGSUSED */ static int bpfopen(dev, flags, fmt, td) dev_t dev; int flags; int fmt; struct thread *td; { struct bpf_d *d; mtx_lock(&bpf_mtx); d = dev->si_drv1; /* * Each minor can be opened by only one process. If the requested * minor is in use, return EBUSY. */ if (d) { mtx_unlock(&bpf_mtx); return (EBUSY); } dev->si_drv1 = (struct bpf_d *)~0; /* mark device in use */ mtx_unlock(&bpf_mtx); if ((dev->si_flags & SI_NAMED) == 0) make_dev(&bpf_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 0600, "bpf%d", dev2unit(dev)); MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK | M_ZERO); dev->si_drv1 = d; d->bd_bufsize = bpf_bufsize; d->bd_sig = SIGIO; d->bd_seesent = 1; #ifdef MAC mac_init_bpfdesc(d); mac_create_bpfdesc(td->td_ucred, d); #endif mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF); callout_init(&d->bd_callout, 1); return (0); } /* * Close the descriptor by detaching it from its interface, * deallocating its buffers, and marking it free. */ /* ARGSUSED */ static int bpfclose(dev, flags, fmt, td) dev_t dev; int flags; int fmt; struct thread *td; { struct bpf_d *d = dev->si_drv1; BPFD_LOCK(d); if (d->bd_state == BPF_WAITING) callout_stop(&d->bd_callout); d->bd_state = BPF_IDLE; BPFD_UNLOCK(d); funsetown(&d->bd_sigio); mtx_lock(&bpf_mtx); if (d->bd_bif) bpf_detachd(d); mtx_unlock(&bpf_mtx); #ifdef MAC mac_destroy_bpfdesc(d); #endif /* MAC */ bpf_freed(d); dev->si_drv1 = 0; free(d, M_BPF); 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 */ static int bpfread(dev, uio, ioflag) dev_t dev; struct uio *uio; int ioflag; { struct bpf_d *d = dev->si_drv1; int timed_out; int error; /* * Restrict application to use a buffer the same size as * as kernel buffers. */ if (uio->uio_resid != d->bd_bufsize) return (EINVAL); BPFD_LOCK(d); if (d->bd_state == BPF_WAITING) callout_stop(&d->bd_callout); timed_out = (d->bd_state == BPF_TIMED_OUT); d->bd_state = BPF_IDLE; /* * 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 || timed_out) && 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; } /* * No data is available, check to see if the bpf device * is still pointed at a real interface. If not, return * ENXIO so that the userland process knows to rebind * it before using it again. */ if (d->bd_bif == NULL) { BPFD_UNLOCK(d); return (ENXIO); } if (ioflag & IO_NDELAY) { BPFD_UNLOCK(d); return (EWOULDBLOCK); } error = msleep(d, &d->bd_mtx, PRINET|PCATCH, "bpf", d->bd_rtout); if (error == EINTR || error == ERESTART) { BPFD_UNLOCK(d); 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) { BPFD_UNLOCK(d); return (0); } ROTATE_BUFFERS(d); break; } } /* * At this point, we know we have something in the hold slot. */ BPFD_UNLOCK(d); /* * 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); BPFD_LOCK(d); d->bd_fbuf = d->bd_hbuf; d->bd_hbuf = 0; d->bd_hlen = 0; BPFD_UNLOCK(d); return (error); } /* * If there are processes sleeping on this descriptor, wake them up. */ static __inline void bpf_wakeup(d) struct bpf_d *d; { if (d->bd_state == BPF_WAITING) { callout_stop(&d->bd_callout); d->bd_state = BPF_IDLE; } wakeup(d); if (d->bd_async && d->bd_sig && d->bd_sigio) pgsigio(&d->bd_sigio, d->bd_sig, 0); selwakeup(&d->bd_sel); } static void bpf_timed_out(arg) void *arg; { struct bpf_d *d = (struct bpf_d *)arg; BPFD_LOCK(d); if (d->bd_state == BPF_WAITING) { d->bd_state = BPF_TIMED_OUT; if (d->bd_slen != 0) bpf_wakeup(d); } BPFD_UNLOCK(d); } static int bpfwrite(dev, uio, ioflag) dev_t dev; struct uio *uio; int ioflag; { struct bpf_d *d = dev->si_drv1; struct ifnet *ifp; struct mbuf *m; int error; static struct sockaddr dst; int datlen; 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, &datlen); if (error) return (error); if (datlen > ifp->if_mtu) return (EMSGSIZE); if (d->bd_hdrcmplt) dst.sa_family = pseudo_AF_HDRCMPLT; mtx_lock(&Giant); #ifdef MAC mac_create_mbuf_from_bpfdesc(d, m); #endif error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0); mtx_unlock(&Giant); /* * The driver frees the mbuf. */ return (error); } /* * Reset a descriptor by flushing its packet buffer and clearing the * receive and drop counts. */ static void reset_d(d) struct bpf_d *d; { mtx_assert(&d->bd_mtx, MA_OWNED); 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. * SIOCGIFADDR Get interface address - convenient hook to driver. * 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 * BIOCGSEESENT Get "see packets sent" flag * BIOCSSEESENT Set "see packets sent" flag */ /* ARGSUSED */ static int bpfioctl(dev, cmd, addr, flags, td) dev_t dev; u_long cmd; caddr_t addr; int flags; struct thread *td; { struct bpf_d *d = dev->si_drv1; int error = 0; BPFD_LOCK(d); if (d->bd_state == BPF_WAITING) callout_stop(&d->bd_callout); d->bd_state = BPF_IDLE; BPFD_UNLOCK(d); switch (cmd) { default: error = EINVAL; break; /* * Check for read packet available. */ case FIONREAD: { int n; BPFD_LOCK(d); n = d->bd_slen; if (d->bd_hbuf) n += d->bd_hlen; BPFD_UNLOCK(d); *(int *)addr = n; break; } case SIOCGIFADDR: { struct ifnet *ifp; if (d->bd_bif == 0) error = EINVAL; else { ifp = d->bd_bif->bif_ifp; error = (*ifp->if_ioctl)(ifp, cmd, addr); } 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); break; /* * Flush read packet buffer. */ case BIOCFLUSH: BPFD_LOCK(d); reset_d(d); BPFD_UNLOCK(d); break; /* * Put interface into promiscuous mode. */ case BIOCPROMISC: if (d->bd_bif == 0) { /* * No interface attached yet. */ error = EINVAL; break; } if (d->bd_promisc == 0) { mtx_lock(&Giant); error = ifpromisc(d->bd_bif->bif_ifp, 1); mtx_unlock(&Giant); if (error == 0) d->bd_promisc = 1; } break; /* * Get current data link type. */ case BIOCGDLT: if (d->bd_bif == 0) error = EINVAL; else *(u_int *)addr = d->bd_bif->bif_dlt; break; /* * Get a list of supported data link types. */ case BIOCGDLTLIST: if (d->bd_bif == 0) error = EINVAL; else error = bpf_getdltlist(d, (struct bpf_dltlist *)addr); break; /* * Set data link type. */ case BIOCSDLT: if (d->bd_bif == 0) error = EINVAL; else error = bpf_setdlt(d, *(u_int *)addr); break; /* * Get interface name. */ case BIOCGETIF: if (d->bd_bif == 0) error = EINVAL; else { struct ifnet *const ifp = d->bd_bif->bif_ifp; struct ifreq *const ifr = (struct ifreq *)addr; snprintf(ifr->ifr_name, sizeof(ifr->ifr_name), "%s%d", ifp->if_name, ifp->if_unit); } break; /* * Set interface. */ case BIOCSETIF: error = bpf_setif(d, (struct ifreq *)addr); break; /* * Set read timeout. */ case BIOCSRTIMEOUT: { struct timeval *tv = (struct timeval *)addr; /* * Subtract 1 tick from tvtohz() since this isn't * a one-shot timer. */ if ((error = itimerfix(tv)) == 0) d->bd_rtout = tvtohz(tv) - 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; } /* * Get "header already complete" flag */ case BIOCGHDRCMPLT: *(u_int *)addr = d->bd_hdrcmplt; break; /* * Set "header already complete" flag */ case BIOCSHDRCMPLT: d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; break; /* * Get "see sent packets" flag */ case BIOCGSEESENT: *(u_int *)addr = d->bd_seesent; break; /* * Set "see sent packets" flag */ case BIOCSSEESENT: d->bd_seesent = *(u_int *)addr; break; case FIONBIO: /* Non-blocking I/O */ break; case FIOASYNC: /* Send signal on receive packets */ d->bd_async = *(int *)addr; break; case FIOSETOWN: error = fsetown(*(int *)addr, &d->bd_sigio); break; case FIOGETOWN: *(int *)addr = fgetown(&d->bd_sigio); break; /* This is deprecated, FIOSETOWN should be used instead. */ case TIOCSPGRP: error = fsetown(-(*(int *)addr), &d->bd_sigio); break; /* This is deprecated, FIOGETOWN should be used instead. */ case TIOCGPGRP: *(int *)addr = -fgetown(&d->bd_sigio); 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. */ static int bpf_setf(d, fp) struct bpf_d *d; struct bpf_program *fp; { struct bpf_insn *fcode, *old; u_int flen, size; old = d->bd_filter; if (fp->bf_insns == 0) { if (fp->bf_len != 0) return (EINVAL); BPFD_LOCK(d); d->bd_filter = 0; reset_d(d); BPFD_UNLOCK(d); if (old != 0) free((caddr_t)old, M_BPF); 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_BPF, M_WAITOK); if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && bpf_validate(fcode, (int)flen)) { BPFD_LOCK(d); d->bd_filter = fcode; reset_d(d); BPFD_UNLOCK(d); if (old != 0) free((caddr_t)old, M_BPF); return (0); } free((caddr_t)fcode, M_BPF); 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. */ static int bpf_setif(d, ifr) struct bpf_d *d; struct ifreq *ifr; { struct bpf_if *bp; int error; struct ifnet *theywant; theywant = ifunit(ifr->ifr_name); if (theywant == 0) return ENXIO; /* * Look through attached interfaces for the named one. */ mtx_lock(&bpf_mtx); for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { struct ifnet *ifp = bp->bif_ifp; if (ifp == 0 || ifp != theywant) continue; /* skip additional entry */ if (bp->bif_driverp != (struct bpf_if **)&ifp->if_bpf) continue; mtx_unlock(&bpf_mtx); /* * 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); } if (bp != d->bd_bif) { if (d->bd_bif) /* * Detach if attached to something else. */ bpf_detachd(d); bpf_attachd(d, bp); } BPFD_LOCK(d); reset_d(d); BPFD_UNLOCK(d); return (0); } mtx_unlock(&bpf_mtx); /* Not found. */ return (ENXIO); } /* * Support for select() and poll() system calls * * Return true iff the specific operation will not block indefinitely. * Otherwise, return false but make a note that a selwakeup() must be done. */ static int bpfpoll(dev, events, td) dev_t dev; int events; struct thread *td; { struct bpf_d *d; int revents; d = dev->si_drv1; if (d->bd_bif == NULL) return (ENXIO); revents = events & (POLLOUT | POLLWRNORM); BPFD_LOCK(d); if (events & (POLLIN | POLLRDNORM)) { /* * An imitation of the FIONREAD ioctl code. * XXX not quite. An exact imitation: * if (d->b_slen != 0 || * (d->bd_hbuf != NULL && d->bd_hlen != 0) */ if (d->bd_hlen != 0 || ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) && d->bd_slen != 0)) revents |= events & (POLLIN | POLLRDNORM); else { selrecord(td, &d->bd_sel); /* Start the read timeout if necessary. */ if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { callout_reset(&d->bd_callout, d->bd_rtout, bpf_timed_out, d); d->bd_state = BPF_WAITING; } } } BPFD_UNLOCK(d); return (revents); } /* * 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(bp, pkt, pktlen) struct bpf_if *bp; u_char *pkt; u_int pktlen; { struct bpf_d *d; u_int slen; BPFIF_LOCK(bp); for (d = bp->bif_dlist; d != 0; d = d->bd_next) { BPFD_LOCK(d); ++d->bd_rcount; slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen); if (slen != 0) { #ifdef MAC if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) #endif catchpacket(d, pkt, pktlen, slen, bcopy); } BPFD_UNLOCK(d); } BPFIF_UNLOCK(bp); } /* * Copy data from an mbuf chain into a buffer. This code is derived * from m_copydata in sys/uipc_mbuf.c. */ static void bpf_mcopy(src_arg, dst_arg, len) 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, void *), 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(bp, m) struct bpf_if *bp; struct mbuf *m; { struct bpf_d *d; u_int pktlen, slen; pktlen = m_length(m, NULL); if (pktlen == m->m_len) { bpf_tap(bp, mtod(m, u_char *), pktlen); return; } BPFIF_LOCK(bp); for (d = bp->bif_dlist; d != 0; d = d->bd_next) { if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL)) continue; BPFD_LOCK(d); ++d->bd_rcount; slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0); if (slen != 0) #ifdef MAC if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) #endif catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); BPFD_UNLOCK(d); } BPFIF_UNLOCK(bp); } /* * 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. */ static void catchpacket(d, pkt, pktlen, snaplen, cpfn) struct bpf_d *d; u_char *pkt; u_int pktlen, snaplen; void (*cpfn)(const void *, void *, size_t); { 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 == 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 || d->bd_state == BPF_TIMED_OUT) /* * Immediate mode is set, or the read timeout has * already expired during a select call. A packet * arrived, so the reader should be woken up. */ bpf_wakeup(d); /* * Append the bpf header. */ hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); microtime(&hp->bh_tstamp); 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; } /* * Initialize all nonzero fields of a descriptor. */ static int bpf_allocbufs(d) struct bpf_d *d; { d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); if (d->bd_fbuf == 0) return (ENOBUFS); d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); if (d->bd_sbuf == 0) { free(d->bd_fbuf, M_BPF); return (ENOBUFS); } d->bd_slen = 0; d->bd_hlen = 0; return (0); } /* * Free buffers currently in use by a descriptor. * Called on close. */ static void bpf_freed(d) 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_BPF); if (d->bd_hbuf != 0) free(d->bd_hbuf, M_BPF); if (d->bd_fbuf != 0) free(d->bd_fbuf, M_BPF); } if (d->bd_filter) free((caddr_t)d->bd_filter, M_BPF); mtx_destroy(&d->bd_mtx); } /* * Attach an interface to bpf. dlt is the link layer type; hdrlen is the * fixed size of the link header (variable length headers not yet supported). */ void bpfattach(ifp, dlt, hdrlen) struct ifnet *ifp; u_int dlt, hdrlen; { bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf); } /* * Attach an interface to bpf. ifp is a pointer to the structure * defining the interface to be attached, dlt is the link layer type, * and hdrlen is the fixed size of the link header (variable length * headers are not yet supporrted). */ void bpfattach2(ifp, dlt, hdrlen, driverp) struct ifnet *ifp; u_int dlt, hdrlen; struct bpf_if **driverp; { struct bpf_if *bp; bp = (struct bpf_if *)malloc(sizeof(*bp), M_BPF, M_NOWAIT | M_ZERO); if (bp == 0) panic("bpfattach"); bp->bif_dlist = 0; bp->bif_driverp = driverp; bp->bif_ifp = ifp; bp->bif_dlt = dlt; mtx_init(&bp->bif_mtx, "bpf interface lock", NULL, MTX_DEF); mtx_lock(&bpf_mtx); bp->bif_next = bpf_iflist; bpf_iflist = bp; mtx_unlock(&bpf_mtx); *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; if (bootverbose) if_printf(ifp, "bpf attached\n"); } /* * Detach bpf from an interface. This involves detaching each descriptor * associated with the interface, and leaving bd_bif NULL. Notify each * descriptor as it's detached so that any sleepers wake up and get * ENXIO. */ void bpfdetach(ifp) struct ifnet *ifp; { struct bpf_if *bp, *bp_prev; struct bpf_d *d; /* Locate BPF interface information */ bp_prev = NULL; mtx_lock(&bpf_mtx); for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { if (ifp == bp->bif_ifp) break; bp_prev = bp; } /* Interface wasn't attached */ if (bp->bif_ifp == NULL) { mtx_unlock(&bpf_mtx); printf("bpfdetach: %s%d was not attached\n", ifp->if_name, ifp->if_unit); return; } if (bp_prev) { bp_prev->bif_next = bp->bif_next; } else { bpf_iflist = bp->bif_next; } mtx_unlock(&bpf_mtx); while ((d = bp->bif_dlist) != NULL) { bpf_detachd(d); BPFD_LOCK(d); bpf_wakeup(d); BPFD_UNLOCK(d); } mtx_destroy(&bp->bif_mtx); free(bp, M_BPF); } /* * Get a list of available data link type of the interface. */ static int bpf_getdltlist(d, bfl) 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; mtx_lock(&bpf_mtx); 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) { mtx_unlock(&bpf_mtx); return (ENOMEM); } error = copyout(&bp->bif_dlt, bfl->bfl_list + n, sizeof(u_int)); } n++; } mtx_unlock(&bpf_mtx); bfl->bfl_len = n; return (error); } /* * Set the data link type of a BPF instance. */ static int bpf_setdlt(d, dlt) struct bpf_d *d; u_int dlt; { int error, opromisc; struct ifnet *ifp; struct bpf_if *bp; if (d->bd_bif->bif_dlt == dlt) return (0); ifp = d->bd_bif->bif_ifp; mtx_lock(&bpf_mtx); for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) break; } mtx_unlock(&bpf_mtx); if (bp != NULL) { BPFD_LOCK(d); opromisc = d->bd_promisc; bpf_detachd(d); bpf_attachd(d, bp); 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; } } return (bp == NULL ? EINVAL : 0); } static void bpf_drvinit(void *unused); static void bpf_clone(void *arg, char *name, int namelen, dev_t *dev); static void bpf_clone(arg, name, namelen, dev) void *arg; char *name; int namelen; dev_t *dev; { int u; if (*dev != NODEV) return; if (dev_stdclone(name, NULL, "bpf", &u) != 1) return; *dev = make_dev(&bpf_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, "bpf%d", u); (*dev)->si_flags |= SI_CHEAPCLONE; return; } static void bpf_drvinit(unused) void *unused; { mtx_init(&bpf_mtx, "bpf global lock", NULL, MTX_DEF); EVENTHANDLER_REGISTER(dev_clone, bpf_clone, 0, 1000); } SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL) #else /* !DEV_BPF && !NETGRAPH_BPF */ /* * NOP stubs to allow bpf-using drivers to load and function. * * A 'better' implementation would allow the core bpf functionality * to be loaded at runtime. */ void bpf_tap(bp, pkt, pktlen) struct bpf_if *bp; u_char *pkt; u_int pktlen; { } void bpf_mtap(bp, m) struct bpf_if *bp; struct mbuf *m; { } void bpfattach(ifp, dlt, hdrlen) struct ifnet *ifp; u_int dlt, hdrlen; { } void bpfdetach(ifp) struct ifnet *ifp; { } u_int bpf_filter(pc, p, wirelen, buflen) const struct bpf_insn *pc; u_char *p; u_int wirelen; u_int buflen; { return -1; /* "no filter" behaviour */ } int bpf_validate(f, len) const struct bpf_insn *f; int len; { return 0; /* false */ } #endif /* !DEV_BPF && !NETGRAPH_BPF */