3cb73e3d8b
avoidance:
- Enable setting the RXCSUM and TXCSUM flags for loopback interfaces;
set both by default.
- When RXCSUM is set, flag packets sent over the loopback interface as
having checked and valid IP, UDP, TCP checksums so that higher
protocol layers won't check them.
- Always clear CSUM_{IP,UDP_TCP} checksum required flags on transmit,
as they will have gotten there as a result of TXCSUM being set.
This is done only for packets explicitly sent over the loopback, not
simulated loopback via if_simloop() due to !SIMPLEX interfaces, etc.
Note that enabling TXCSUM but not RXCSUM will lead to unhappiness, as
checksums won't be generated but will be validated.
Kris reports that this leads to significant performance improvements
in loopback benchmarking with TCP and UDP for throughput:
RXCSUM RXCSUM+TXCSUM
TCP 15% 37%
UDP 10% 74%
Update man page.
Reviewed by: sam
Tested by: kris
MFC after: 1 week
420 lines
9.4 KiB
C
420 lines
9.4 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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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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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* @(#)if_loop.c 8.2 (Berkeley) 1/9/95
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* $FreeBSD$
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*/
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/*
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* Loopback interface driver for protocol testing and timing.
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*/
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#include "opt_atalk.h"
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include "opt_ipx.h"
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#include "opt_route.h"
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/mbuf.h>
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#include <sys/module.h>
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#include <machine/bus.h>
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#include <sys/rman.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/sysctl.h>
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#include <sys/vimage.h>
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#include <net/if.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/netisr.h>
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#include <net/route.h>
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#include <net/bpf.h>
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#include <net/vnet.h>
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#ifdef INET
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#endif
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#ifdef IPX
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#include <netipx/ipx.h>
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#include <netipx/ipx_if.h>
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#endif
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#ifdef INET6
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#ifndef INET
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#include <netinet/in.h>
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#endif
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#include <netinet6/in6_var.h>
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#include <netinet/ip6.h>
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#endif
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#ifdef NETATALK
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#include <netatalk/at.h>
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#include <netatalk/at_var.h>
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#endif
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#include <security/mac/mac_framework.h>
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#ifdef TINY_LOMTU
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#define LOMTU (1024+512)
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#elif defined(LARGE_LOMTU)
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#define LOMTU 131072
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#else
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#define LOMTU 16384
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#endif
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int loioctl(struct ifnet *, u_long, caddr_t);
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static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
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int looutput(struct ifnet *ifp, struct mbuf *m,
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struct sockaddr *dst, struct rtentry *rt);
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static int lo_clone_create(struct if_clone *, int, caddr_t);
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static void lo_clone_destroy(struct ifnet *);
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#ifdef VIMAGE_GLOBALS
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struct ifnet *loif; /* Used externally */
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#endif
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IFC_SIMPLE_DECLARE(lo, 1);
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static void
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lo_clone_destroy(struct ifnet *ifp)
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{
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#ifdef INVARIANTS
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INIT_VNET_NET(ifp->if_vnet);
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#endif
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/* XXX: destroying lo0 will lead to panics. */
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KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
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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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lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
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{
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INIT_VNET_NET(curvnet);
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struct ifnet *ifp;
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ifp = if_alloc(IFT_LOOP);
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if (ifp == NULL)
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return (ENOSPC);
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if_initname(ifp, ifc->ifc_name, unit);
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ifp->if_mtu = LOMTU;
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ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
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ifp->if_ioctl = loioctl;
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ifp->if_output = looutput;
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ifp->if_snd.ifq_maxlen = ifqmaxlen;
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ifp->if_hwassist = ifp->if_capabilities = ifp->if_capenable =
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IFCAP_HWCSUM;
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if_attach(ifp);
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bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
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if (V_loif == NULL)
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V_loif = ifp;
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return (0);
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}
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static int
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loop_modevent(module_t mod, int type, void *data)
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{
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INIT_VNET_NET(curvnet);
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switch (type) {
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case MOD_LOAD:
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V_loif = NULL;
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if_clone_attach(&lo_cloner);
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break;
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case MOD_UNLOAD:
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printf("loop module unload - not possible for this module type\n");
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return (EINVAL);
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default:
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return (EOPNOTSUPP);
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}
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return (0);
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}
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static moduledata_t loop_mod = {
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"loop",
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loop_modevent,
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0
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};
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DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
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int
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looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
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struct rtentry *rt)
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{
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u_int32_t af;
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#ifdef MAC
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int error;
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#endif
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M_ASSERTPKTHDR(m); /* check if we have the packet header */
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#ifdef MAC
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error = mac_ifnet_check_transmit(ifp, m);
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if (error) {
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m_freem(m);
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return (error);
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}
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#endif
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if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
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m_freem(m);
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return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
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rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
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}
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ifp->if_opackets++;
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ifp->if_obytes += m->m_pkthdr.len;
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/* BPF writes need to be handled specially. */
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if (dst->sa_family == AF_UNSPEC) {
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bcopy(dst->sa_data, &af, sizeof(af));
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dst->sa_family = af;
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}
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#if 1 /* XXX */
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switch (dst->sa_family) {
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case AF_INET:
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if (ifp->if_capenable & IFCAP_RXCSUM) {
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m->m_pkthdr.csum_data = 0xffff;
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m->m_pkthdr.csum_flags = CSUM_DATA_VALID |
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CSUM_PSEUDO_HDR | CSUM_IP_CHECKED |
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CSUM_IP_VALID | CSUM_SCTP_VALID;
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}
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m->m_pkthdr.csum_flags &= ~(CSUM_IP | CSUM_TCP | CSUM_UDP);
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case AF_INET6:
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case AF_IPX:
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case AF_APPLETALK:
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break;
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default:
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printf("looutput: af=%d unexpected\n", dst->sa_family);
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m_freem(m);
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return (EAFNOSUPPORT);
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}
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#endif
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return (if_simloop(ifp, m, dst->sa_family, 0));
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}
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/*
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* if_simloop()
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*
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* This function is to support software emulation of hardware loopback,
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* i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
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* hear their own broadcasts, we create a copy of the packet that we
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* would normally receive via a hardware loopback.
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*
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* This function expects the packet to include the media header of length hlen.
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*/
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int
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if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
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{
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INIT_VNET_NET(ifp->if_vnet);
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int isr;
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M_ASSERTPKTHDR(m);
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m_tag_delete_nonpersistent(m);
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m->m_pkthdr.rcvif = ifp;
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#ifdef MAC
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mac_ifnet_create_mbuf(ifp, m);
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#endif
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/*
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* Let BPF see incoming packet in the following manner:
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* - Emulated packet loopback for a simplex interface
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* (net/if_ethersubr.c)
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* -> passes it to ifp's BPF
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* - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
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* -> not passes it to any BPF
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* - Normal packet loopback from myself to myself (net/if_loop.c)
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* -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
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*/
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if (hlen > 0) {
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if (bpf_peers_present(ifp->if_bpf)) {
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bpf_mtap(ifp->if_bpf, m);
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}
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} else {
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if (bpf_peers_present(V_loif->if_bpf)) {
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if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
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/* XXX beware sizeof(af) != 4 */
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u_int32_t af1 = af;
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/*
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* We need to prepend the address family.
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*/
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bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
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}
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}
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}
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/* Strip away media header */
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if (hlen > 0) {
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m_adj(m, hlen);
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#ifndef __NO_STRICT_ALIGNMENT
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/*
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* Some archs do not like unaligned data, so
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* we move data down in the first mbuf.
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*/
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if (mtod(m, vm_offset_t) & 3) {
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KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
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bcopy(m->m_data,
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(char *)(mtod(m, vm_offset_t)
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- (mtod(m, vm_offset_t) & 3)),
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m->m_len);
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m->m_data -= (mtod(m,vm_offset_t) & 3);
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}
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#endif
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}
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/* Deliver to upper layer protocol */
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switch (af) {
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#ifdef INET
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case AF_INET:
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isr = NETISR_IP;
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break;
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#endif
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#ifdef INET6
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case AF_INET6:
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m->m_flags |= M_LOOP;
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isr = NETISR_IPV6;
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break;
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#endif
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#ifdef IPX
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case AF_IPX:
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isr = NETISR_IPX;
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break;
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#endif
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#ifdef NETATALK
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case AF_APPLETALK:
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isr = NETISR_ATALK2;
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break;
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#endif
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default:
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printf("if_simloop: can't handle af=%d\n", af);
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m_freem(m);
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return (EAFNOSUPPORT);
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}
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ifp->if_ipackets++;
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ifp->if_ibytes += m->m_pkthdr.len;
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netisr_queue(isr, m); /* mbuf is free'd on failure. */
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return (0);
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}
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/* ARGSUSED */
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static void
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lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
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{
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RT_LOCK_ASSERT(rt);
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rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
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}
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/*
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* Process an ioctl request.
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*/
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/* ARGSUSED */
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int
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loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
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{
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struct ifaddr *ifa;
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struct ifreq *ifr = (struct ifreq *)data;
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int error = 0, mask;
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switch (cmd) {
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case SIOCSIFADDR:
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ifp->if_flags |= IFF_UP;
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ifp->if_drv_flags |= IFF_DRV_RUNNING;
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ifa = (struct ifaddr *)data;
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ifa->ifa_rtrequest = lortrequest;
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/*
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* Everything else is done at a higher level.
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*/
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break;
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case SIOCADDMULTI:
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case SIOCDELMULTI:
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if (ifr == 0) {
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error = EAFNOSUPPORT; /* XXX */
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break;
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}
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switch (ifr->ifr_addr.sa_family) {
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#ifdef INET
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case AF_INET:
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break;
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#endif
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#ifdef INET6
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case AF_INET6:
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break;
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#endif
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default:
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error = EAFNOSUPPORT;
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break;
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}
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break;
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case SIOCSIFMTU:
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ifp->if_mtu = ifr->ifr_mtu;
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break;
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case SIOCSIFFLAGS:
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break;
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case SIOCSIFCAP:
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mask = ifp->if_capenable ^ ifr->ifr_reqcap;
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if ((mask & IFCAP_RXCSUM) != 0)
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ifp->if_capenable ^= IFCAP_RXCSUM;
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if ((mask & IFCAP_TXCSUM) != 0)
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ifp->if_capenable ^= IFCAP_TXCSUM;
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if (ifp->if_capenable & IFCAP_TXCSUM)
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ifp->if_hwassist = CSUM_IP | CSUM_TCP | CSUM_UDP;
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else
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ifp->if_hwassist = 0;
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break;
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default:
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error = EINVAL;
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}
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return (error);
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}
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