After r343631 pfil hooks are invoked in net_epoch_preempt section, this allows to avoid extra locking. Add NET_EPOCH_ASSER() assertion to each ipfw_bpf_*tap*() call to require to be called from inside epoch section. Use NET_EPOCH_WAIT() in ipfw_clone_destroy() to wait until it becomes safe to free() ifnet. And use on-stack ifnet pointer in each ipfw_bpf_*tap*() call to avoid NULL pointer dereference in case when V_*log_if global variable will become NULL during ipfw_bpf_*tap*() call. Sponsored by: Yandex LLC
210 lines
4.9 KiB
C
210 lines
4.9 KiB
C
/*-
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* Copyright (c) 2016 Yandex LLC
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* Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/socket.h>
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#include <net/ethernet.h>
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#include <net/if.h>
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#include <net/if_pflog.h>
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#include <net/if_var.h>
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#include <net/if_clone.h>
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#include <net/if_types.h>
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#include <net/vnet.h>
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#include <net/bpf.h>
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#include <netinet/in.h>
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#include <netinet/ip_fw.h>
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#include <netinet/ip_var.h>
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#include <netpfil/ipfw/ip_fw_private.h>
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VNET_DEFINE_STATIC(struct ifnet *, log_if);
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VNET_DEFINE_STATIC(struct ifnet *, pflog_if);
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VNET_DEFINE_STATIC(struct if_clone *, ipfw_cloner);
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VNET_DEFINE_STATIC(struct if_clone *, ipfwlog_cloner);
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#define V_ipfw_cloner VNET(ipfw_cloner)
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#define V_ipfwlog_cloner VNET(ipfwlog_cloner)
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#define V_log_if VNET(log_if)
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#define V_pflog_if VNET(pflog_if)
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static const char ipfwname[] = "ipfw";
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static const char ipfwlogname[] = "ipfwlog";
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static int
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ipfw_bpf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
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{
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return (EINVAL);
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}
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static int
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ipfw_bpf_output(struct ifnet *ifp, struct mbuf *m,
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const struct sockaddr *dst, struct route *ro)
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{
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if (m != NULL)
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FREE_PKT(m);
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return (0);
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}
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static void
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ipfw_clone_destroy(struct ifnet *ifp)
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{
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if (ifp->if_hdrlen == ETHER_HDR_LEN)
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V_log_if = NULL;
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else
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V_pflog_if = NULL;
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NET_EPOCH_WAIT();
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bpfdetach(ifp);
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if_detach(ifp);
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if_free(ifp);
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}
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static int
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ipfw_clone_create(struct if_clone *ifc, int unit, caddr_t params)
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{
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struct ifnet *ifp;
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ifp = if_alloc(IFT_PFLOG);
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if (ifp == NULL)
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return (ENOSPC);
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if_initname(ifp, ipfwname, unit);
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ifp->if_flags = IFF_UP | IFF_SIMPLEX | IFF_MULTICAST;
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ifp->if_mtu = 65536;
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ifp->if_ioctl = ipfw_bpf_ioctl;
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ifp->if_output = ipfw_bpf_output;
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ifp->if_hdrlen = ETHER_HDR_LEN;
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if_attach(ifp);
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bpfattach(ifp, DLT_EN10MB, ETHER_HDR_LEN);
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if (V_log_if != NULL) {
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bpfdetach(ifp);
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if_detach(ifp);
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if_free(ifp);
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return (EEXIST);
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}
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V_log_if = ifp;
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return (0);
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}
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static int
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ipfwlog_clone_create(struct if_clone *ifc, int unit, caddr_t params)
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{
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struct ifnet *ifp;
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ifp = if_alloc(IFT_PFLOG);
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if (ifp == NULL)
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return (ENOSPC);
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if_initname(ifp, ipfwlogname, unit);
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ifp->if_flags = IFF_UP | IFF_SIMPLEX | IFF_MULTICAST;
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ifp->if_mtu = 65536;
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ifp->if_ioctl = ipfw_bpf_ioctl;
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ifp->if_output = ipfw_bpf_output;
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ifp->if_hdrlen = PFLOG_HDRLEN;
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if_attach(ifp);
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bpfattach(ifp, DLT_PFLOG, PFLOG_HDRLEN);
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if (V_pflog_if != NULL) {
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bpfdetach(ifp);
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if_detach(ifp);
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if_free(ifp);
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return (EEXIST);
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}
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V_pflog_if = ifp;
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return (0);
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}
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void
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ipfw_bpf_tap(u_char *pkt, u_int pktlen)
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{
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struct ifnet *ifp = V_log_if;
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NET_EPOCH_ASSERT();
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if (ifp != NULL)
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BPF_TAP(ifp, pkt, pktlen);
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}
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void
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ipfw_bpf_mtap(struct mbuf *m)
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{
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struct ifnet *ifp = V_log_if;
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NET_EPOCH_ASSERT();
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if (ifp != NULL)
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BPF_MTAP(ifp, m);
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}
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void
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ipfw_bpf_mtap2(void *data, u_int dlen, struct mbuf *m)
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{
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struct ifnet *logif;
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NET_EPOCH_ASSERT();
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switch (dlen) {
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case (ETHER_HDR_LEN):
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logif = V_log_if;
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break;
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case (PFLOG_HDRLEN):
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logif = V_pflog_if;
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break;
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default:
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#ifdef INVARIANTS
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panic("%s: unsupported len %d", __func__, dlen);
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#endif
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logif = NULL;
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}
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if (logif != NULL)
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BPF_MTAP2(logif, data, dlen, m);
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}
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void
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ipfw_bpf_init(int first __unused)
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{
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V_log_if = NULL;
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V_pflog_if = NULL;
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V_ipfw_cloner = if_clone_simple(ipfwname, ipfw_clone_create,
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ipfw_clone_destroy, 0);
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V_ipfwlog_cloner = if_clone_simple(ipfwlogname, ipfwlog_clone_create,
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ipfw_clone_destroy, 0);
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}
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void
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ipfw_bpf_uninit(int last __unused)
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{
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if_clone_detach(V_ipfw_cloner);
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if_clone_detach(V_ipfwlog_cloner);
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}
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