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freebsd-skq/sys/netinet/ip_output.c
glebius 9879d0d15d Make ip6_output() and ip_output() require network epoch. 
All callers that before may called into these functions
without network epoch now must enter it.
2020-01-22 05:51:22 +00:00

1578 lines
39 KiB
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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1988, 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ip_output.c 8.3 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_ipsec.h"
#include "opt_kern_tls.h"
#include "opt_mbuf_stress_test.h"
#include "opt_mpath.h"
#include "opt_ratelimit.h"
#include "opt_route.h"
#include "opt_rss.h"
#include "opt_sctp.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktls.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/rmlock.h>
#include <sys/sdt.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/ucred.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_llatbl.h>
#include <net/netisr.h>
#include <net/pfil.h>
#include <net/route.h>
#ifdef RADIX_MPATH
#include <net/radix_mpath.h>
#endif
#include <net/rss_config.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_fib.h>
#include <netinet/in_kdtrace.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_rss.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#ifdef SCTP
#include <netinet/sctp.h>
#include <netinet/sctp_crc32.h>
#endif
#include <netipsec/ipsec_support.h>
#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>
#ifdef MBUF_STRESS_TEST
static int mbuf_frag_size = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
&mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
#endif
static void ip_mloopback(struct ifnet *, const struct mbuf *, int);
extern int in_mcast_loop;
extern struct protosw inetsw[];
static inline int
ip_output_pfil(struct mbuf **mp, struct ifnet *ifp, int flags,
struct inpcb *inp, struct sockaddr_in *dst, int *fibnum, int *error)
{
struct m_tag *fwd_tag = NULL;
struct mbuf *m;
struct in_addr odst;
struct ip *ip;
int pflags = PFIL_OUT;
if (flags & IP_FORWARDING)
pflags |= PFIL_FWD;
m = *mp;
ip = mtod(m, struct ip *);
/* Run through list of hooks for output packets. */
odst.s_addr = ip->ip_dst.s_addr;
switch (pfil_run_hooks(V_inet_pfil_head, mp, ifp, pflags, inp)) {
case PFIL_DROPPED:
*error = EACCES;
/* FALLTHROUGH */
case PFIL_CONSUMED:
return 1; /* Finished */
case PFIL_PASS:
*error = 0;
}
m = *mp;
ip = mtod(m, struct ip *);
/* See if destination IP address was changed by packet filter. */
if (odst.s_addr != ip->ip_dst.s_addr) {
m->m_flags |= M_SKIP_FIREWALL;
/* If destination is now ourself drop to ip_input(). */
if (in_localip(ip->ip_dst)) {
m->m_flags |= M_FASTFWD_OURS;
if (m->m_pkthdr.rcvif == NULL)
m->m_pkthdr.rcvif = V_loif;
if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
m->m_pkthdr.csum_flags |=
CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
m->m_pkthdr.csum_data = 0xffff;
}
m->m_pkthdr.csum_flags |=
CSUM_IP_CHECKED | CSUM_IP_VALID;
#ifdef SCTP
if (m->m_pkthdr.csum_flags & CSUM_SCTP)
m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
#endif
*error = netisr_queue(NETISR_IP, m);
return 1; /* Finished */
}
bzero(dst, sizeof(*dst));
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = ip->ip_dst;
return -1; /* Reloop */
}
/* See if fib was changed by packet filter. */
if ((*fibnum) != M_GETFIB(m)) {
m->m_flags |= M_SKIP_FIREWALL;
*fibnum = M_GETFIB(m);
return -1; /* Reloop for FIB change */
}
/* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
if (m->m_flags & M_FASTFWD_OURS) {
if (m->m_pkthdr.rcvif == NULL)
m->m_pkthdr.rcvif = V_loif;
if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
m->m_pkthdr.csum_flags |=
CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
m->m_pkthdr.csum_data = 0xffff;
}
#ifdef SCTP
if (m->m_pkthdr.csum_flags & CSUM_SCTP)
m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
#endif
m->m_pkthdr.csum_flags |=
CSUM_IP_CHECKED | CSUM_IP_VALID;
*error = netisr_queue(NETISR_IP, m);
return 1; /* Finished */
}
/* Or forward to some other address? */
if ((m->m_flags & M_IP_NEXTHOP) &&
((fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL)) {
bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
m->m_flags |= M_SKIP_FIREWALL;
m->m_flags &= ~M_IP_NEXTHOP;
m_tag_delete(m, fwd_tag);
return -1; /* Reloop for CHANGE of dst */
}
return 0;
}
static int
ip_output_send(struct inpcb *inp, struct ifnet *ifp, struct mbuf *m,
const struct sockaddr_in *gw, struct route *ro, bool stamp_tag)
{
#ifdef KERN_TLS
struct ktls_session *tls = NULL;
#endif
struct m_snd_tag *mst;
int error;
MPASS((m->m_pkthdr.csum_flags & CSUM_SND_TAG) == 0);
mst = NULL;
#ifdef KERN_TLS
/*
* If this is an unencrypted TLS record, save a reference to
* the record. This local reference is used to call
* ktls_output_eagain after the mbuf has been freed (thus
* dropping the mbuf's reference) in if_output.
*/
if (m->m_next != NULL && mbuf_has_tls_session(m->m_next)) {
tls = ktls_hold(m->m_next->m_ext.ext_pgs->tls);
mst = tls->snd_tag;
/*
* If a TLS session doesn't have a valid tag, it must
* have had an earlier ifp mismatch, so drop this
* packet.
*/
if (mst == NULL) {
error = EAGAIN;
goto done;
}
}
#endif
#ifdef RATELIMIT
if (inp != NULL && mst == NULL) {
if ((inp->inp_flags2 & INP_RATE_LIMIT_CHANGED) != 0 ||
(inp->inp_snd_tag != NULL &&
inp->inp_snd_tag->ifp != ifp))
in_pcboutput_txrtlmt(inp, ifp, m);
if (inp->inp_snd_tag != NULL)
mst = inp->inp_snd_tag;
}
#endif
if (stamp_tag && mst != NULL) {
KASSERT(m->m_pkthdr.rcvif == NULL,
("trying to add a send tag to a forwarded packet"));
if (mst->ifp != ifp) {
error = EAGAIN;
goto done;
}
/* stamp send tag on mbuf */
m->m_pkthdr.snd_tag = m_snd_tag_ref(mst);
m->m_pkthdr.csum_flags |= CSUM_SND_TAG;
}
error = (*ifp->if_output)(ifp, m, (const struct sockaddr *)gw, ro);
done:
/* Check for route change invalidating send tags. */
#ifdef KERN_TLS
if (tls != NULL) {
if (error == EAGAIN)
error = ktls_output_eagain(inp, tls);
ktls_free(tls);
}
#endif
#ifdef RATELIMIT
if (error == EAGAIN)
in_pcboutput_eagain(inp);
#endif
return (error);
}
/*
* IP output. The packet in mbuf chain m contains a skeletal IP
* header (with len, off, ttl, proto, tos, src, dst).
* The mbuf chain containing the packet will be freed.
* The mbuf opt, if present, will not be freed.
* If route ro is present and has ro_rt initialized, route lookup would be
* skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
* then result of route lookup is stored in ro->ro_rt.
*
* In the IP forwarding case, the packet will arrive with options already
* inserted, so must have a NULL opt pointer.
*/
int
ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
struct ip_moptions *imo, struct inpcb *inp)
{
struct rm_priotracker in_ifa_tracker;
struct ip *ip;
struct ifnet *ifp = NULL; /* keep compiler happy */
struct mbuf *m0;
int hlen = sizeof (struct ip);
int mtu;
int error = 0;
struct sockaddr_in *dst, sin;
const struct sockaddr_in *gw;
struct in_ifaddr *ia;
struct in_addr src;
int isbroadcast;
uint16_t ip_len, ip_off;
uint32_t fibnum;
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
int no_route_but_check_spd = 0;
#endif
M_ASSERTPKTHDR(m);
NET_EPOCH_ASSERT();
if (inp != NULL) {
INP_LOCK_ASSERT(inp);
M_SETFIB(m, inp->inp_inc.inc_fibnum);
if ((flags & IP_NODEFAULTFLOWID) == 0) {
m->m_pkthdr.flowid = inp->inp_flowid;
M_HASHTYPE_SET(m, inp->inp_flowtype);
}
#ifdef NUMA
m->m_pkthdr.numa_domain = inp->inp_numa_domain;
#endif
}
if (opt) {
int len = 0;
m = ip_insertoptions(m, opt, &len);
if (len != 0)
hlen = len; /* ip->ip_hl is updated above */
}
ip = mtod(m, struct ip *);
ip_len = ntohs(ip->ip_len);
ip_off = ntohs(ip->ip_off);
if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
ip->ip_v = IPVERSION;
ip->ip_hl = hlen >> 2;
ip_fillid(ip);
} else {
/* Header already set, fetch hlen from there */
hlen = ip->ip_hl << 2;
}
if ((flags & IP_FORWARDING) == 0)
IPSTAT_INC(ips_localout);
/*
* dst/gw handling:
*
* gw is readonly but can point either to dst OR rt_gateway,
* therefore we need restore gw if we're redoing lookup.
*/
fibnum = (inp != NULL) ? inp->inp_inc.inc_fibnum : M_GETFIB(m);
if (ro != NULL)
dst = (struct sockaddr_in *)&ro->ro_dst;
else
dst = &sin;
if (ro == NULL || ro->ro_rt == NULL) {
bzero(dst, sizeof(*dst));
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = ip->ip_dst;
}
gw = dst;
again:
/*
* Validate route against routing table additions;
* a better/more specific route might have been added.
*/
if (inp != NULL && ro != NULL && ro->ro_rt != NULL)
RT_VALIDATE(ro, &inp->inp_rt_cookie, fibnum);
/*
* If there is a cached route,
* check that it is to the same destination
* and is still up. If not, free it and try again.
* The address family should also be checked in case of sharing the
* cache with IPv6.
* Also check whether routing cache needs invalidation.
*/
if (ro != NULL && ro->ro_rt != NULL &&
((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
ro->ro_rt->rt_ifp == NULL || !RT_LINK_IS_UP(ro->ro_rt->rt_ifp) ||
dst->sin_family != AF_INET ||
dst->sin_addr.s_addr != ip->ip_dst.s_addr))
RO_INVALIDATE_CACHE(ro);
ia = NULL;
/*
* If routing to interface only, short circuit routing lookup.
* The use of an all-ones broadcast address implies this; an
* interface is specified by the broadcast address of an interface,
* or the destination address of a ptp interface.
*/
if (flags & IP_SENDONES) {
if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst),
M_GETFIB(m)))) == NULL &&
(ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst),
M_GETFIB(m)))) == NULL) {
IPSTAT_INC(ips_noroute);
error = ENETUNREACH;
goto bad;
}
ip->ip_dst.s_addr = INADDR_BROADCAST;
dst->sin_addr = ip->ip_dst;
ifp = ia->ia_ifp;
mtu = ifp->if_mtu;
ip->ip_ttl = 1;
isbroadcast = 1;
src = IA_SIN(ia)->sin_addr;
} else if (flags & IP_ROUTETOIF) {
if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst),
M_GETFIB(m)))) == NULL &&
(ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0,
M_GETFIB(m)))) == NULL) {
IPSTAT_INC(ips_noroute);
error = ENETUNREACH;
goto bad;
}
ifp = ia->ia_ifp;
mtu = ifp->if_mtu;
ip->ip_ttl = 1;
isbroadcast = ifp->if_flags & IFF_BROADCAST ?
in_ifaddr_broadcast(dst->sin_addr, ia) : 0;
src = IA_SIN(ia)->sin_addr;
} else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
imo != NULL && imo->imo_multicast_ifp != NULL) {
/*
* Bypass the normal routing lookup for multicast
* packets if the interface is specified.
*/
ifp = imo->imo_multicast_ifp;
mtu = ifp->if_mtu;
IFP_TO_IA(ifp, ia, &in_ifa_tracker);
isbroadcast = 0; /* fool gcc */
/* Interface may have no addresses. */
if (ia != NULL)
src = IA_SIN(ia)->sin_addr;
else
src.s_addr = INADDR_ANY;
} else if (ro != NULL) {
if (ro->ro_rt == NULL) {
/*
* We want to do any cloning requested by the link
* layer, as this is probably required in all cases
* for correct operation (as it is for ARP).
*/
#ifdef RADIX_MPATH
rtalloc_mpath_fib(ro,
ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
fibnum);
#else
in_rtalloc_ign(ro, 0, fibnum);
#endif
if (ro->ro_rt == NULL ||
(ro->ro_rt->rt_flags & RTF_UP) == 0 ||
ro->ro_rt->rt_ifp == NULL ||
!RT_LINK_IS_UP(ro->ro_rt->rt_ifp)) {
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
/*
* There is no route for this packet, but it is
* possible that a matching SPD entry exists.
*/
no_route_but_check_spd = 1;
mtu = 0; /* Silence GCC warning. */
goto sendit;
#endif
IPSTAT_INC(ips_noroute);
error = EHOSTUNREACH;
goto bad;
}
}
ia = ifatoia(ro->ro_rt->rt_ifa);
ifp = ro->ro_rt->rt_ifp;
counter_u64_add(ro->ro_rt->rt_pksent, 1);
rt_update_ro_flags(ro);
if (ro->ro_rt->rt_flags & RTF_GATEWAY)
gw = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
if (ro->ro_rt->rt_flags & RTF_HOST)
isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
else if (ifp->if_flags & IFF_BROADCAST)
isbroadcast = in_ifaddr_broadcast(gw->sin_addr, ia);
else
isbroadcast = 0;
if (ro->ro_rt->rt_flags & RTF_HOST)
mtu = ro->ro_rt->rt_mtu;
else
mtu = ifp->if_mtu;
src = IA_SIN(ia)->sin_addr;
} else {
struct nhop4_extended nh;
bzero(&nh, sizeof(nh));
if (fib4_lookup_nh_ext(M_GETFIB(m), ip->ip_dst, 0, 0, &nh) !=
0) {
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
/*
* There is no route for this packet, but it is
* possible that a matching SPD entry exists.
*/
no_route_but_check_spd = 1;
mtu = 0; /* Silence GCC warning. */
goto sendit;
#endif
IPSTAT_INC(ips_noroute);
error = EHOSTUNREACH;
goto bad;
}
ifp = nh.nh_ifp;
mtu = nh.nh_mtu;
/*
* We are rewriting here dst to be gw actually, contradicting
* comment at the beginning of the function. However, in this
* case we are always dealing with on stack dst.
* In case if pfil(9) sends us back to beginning of the
* function, the dst would be rewritten by ip_output_pfil().
*/
MPASS(dst == &sin);
dst->sin_addr = nh.nh_addr;
ia = nh.nh_ia;
src = nh.nh_src;
isbroadcast = (((nh.nh_flags & (NHF_HOST | NHF_BROADCAST)) ==
(NHF_HOST | NHF_BROADCAST)) ||
((ifp->if_flags & IFF_BROADCAST) &&
in_ifaddr_broadcast(dst->sin_addr, ia)));
}
/* Catch a possible divide by zero later. */
KASSERT(mtu > 0, ("%s: mtu %d <= 0, ro=%p (rt_flags=0x%08x) ifp=%p",
__func__, mtu, ro,
(ro != NULL && ro->ro_rt != NULL) ? ro->ro_rt->rt_flags : 0, ifp));
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
m->m_flags |= M_MCAST;
/*
* IP destination address is multicast. Make sure "gw"
* still points to the address in "ro". (It may have been
* changed to point to a gateway address, above.)
*/
gw = dst;
/*
* See if the caller provided any multicast options
*/
if (imo != NULL) {
ip->ip_ttl = imo->imo_multicast_ttl;
if (imo->imo_multicast_vif != -1)
ip->ip_src.s_addr =
ip_mcast_src ?
ip_mcast_src(imo->imo_multicast_vif) :
INADDR_ANY;
} else
ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
/*
* Confirm that the outgoing interface supports multicast.
*/
if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
if ((ifp->if_flags & IFF_MULTICAST) == 0) {
IPSTAT_INC(ips_noroute);
error = ENETUNREACH;
goto bad;
}
}
/*
* If source address not specified yet, use address
* of outgoing interface.
*/
if (ip->ip_src.s_addr == INADDR_ANY)
ip->ip_src = src;
if ((imo == NULL && in_mcast_loop) ||
(imo && imo->imo_multicast_loop)) {
/*
* Loop back multicast datagram if not expressly
* forbidden to do so, even if we are not a member
* of the group; ip_input() will filter it later,
* thus deferring a hash lookup and mutex acquisition
* at the expense of a cheap copy using m_copym().
*/
ip_mloopback(ifp, m, hlen);
} else {
/*
* If we are acting as a multicast router, perform
* multicast forwarding as if the packet had just
* arrived on the interface to which we are about
* to send. The multicast forwarding function
* recursively calls this function, using the
* IP_FORWARDING flag to prevent infinite recursion.
*
* Multicasts that are looped back by ip_mloopback(),
* above, will be forwarded by the ip_input() routine,
* if necessary.
*/
if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
/*
* If rsvp daemon is not running, do not
* set ip_moptions. This ensures that the packet
* is multicast and not just sent down one link
* as prescribed by rsvpd.
*/
if (!V_rsvp_on)
imo = NULL;
if (ip_mforward &&
ip_mforward(ip, ifp, m, imo) != 0) {
m_freem(m);
goto done;
}
}
}
/*
* Multicasts with a time-to-live of zero may be looped-
* back, above, but must not be transmitted on a network.
* Also, multicasts addressed to the loopback interface
* are not sent -- the above call to ip_mloopback() will
* loop back a copy. ip_input() will drop the copy if
* this host does not belong to the destination group on
* the loopback interface.
*/
if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
m_freem(m);
goto done;
}
goto sendit;
}
/*
* If the source address is not specified yet, use the address
* of the outoing interface.
*/
if (ip->ip_src.s_addr == INADDR_ANY)
ip->ip_src = src;
/*
* Look for broadcast address and
* verify user is allowed to send
* such a packet.
*/
if (isbroadcast) {
if ((ifp->if_flags & IFF_BROADCAST) == 0) {
error = EADDRNOTAVAIL;
goto bad;
}
if ((flags & IP_ALLOWBROADCAST) == 0) {
error = EACCES;
goto bad;
}
/* don't allow broadcast messages to be fragmented */
if (ip_len > mtu) {
error = EMSGSIZE;
goto bad;
}
m->m_flags |= M_BCAST;
} else {
m->m_flags &= ~M_BCAST;
}
sendit:
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
if (IPSEC_ENABLED(ipv4)) {
if ((error = IPSEC_OUTPUT(ipv4, m, inp)) != 0) {
if (error == EINPROGRESS)
error = 0;
goto done;
}
}
/*
* Check if there was a route for this packet; return error if not.
*/
if (no_route_but_check_spd) {
IPSTAT_INC(ips_noroute);
error = EHOSTUNREACH;
goto bad;
}
/* Update variables that are affected by ipsec4_output(). */
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
#endif /* IPSEC */
/* Jump over all PFIL processing if hooks are not active. */
if (PFIL_HOOKED_OUT(V_inet_pfil_head)) {
switch (ip_output_pfil(&m, ifp, flags, inp, dst, &fibnum,
&error)) {
case 1: /* Finished */
goto done;
case 0: /* Continue normally */
ip = mtod(m, struct ip *);
break;
case -1: /* Need to try again */
/* Reset everything for a new round */
if (ro != NULL) {
RO_RTFREE(ro);
ro->ro_prepend = NULL;
}
gw = dst;
ip = mtod(m, struct ip *);
goto again;
}
}
/* IN_LOOPBACK must not appear on the wire - RFC1122. */
if (IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) {
if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
IPSTAT_INC(ips_badaddr);
error = EADDRNOTAVAIL;
goto bad;
}
}
m->m_pkthdr.csum_flags |= CSUM_IP;
if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA & ~ifp->if_hwassist) {
m = mb_unmapped_to_ext(m);
if (m == NULL) {
IPSTAT_INC(ips_odropped);
error = ENOBUFS;
goto bad;
}
in_delayed_cksum(m);
m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
} else if ((ifp->if_capenable & IFCAP_NOMAP) == 0) {
m = mb_unmapped_to_ext(m);
if (m == NULL) {
IPSTAT_INC(ips_odropped);
error = ENOBUFS;
goto bad;
}
}
#ifdef SCTP
if (m->m_pkthdr.csum_flags & CSUM_SCTP & ~ifp->if_hwassist) {
m = mb_unmapped_to_ext(m);
if (m == NULL) {
IPSTAT_INC(ips_odropped);
error = ENOBUFS;
goto bad;
}
sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
}
#endif
/*
* If small enough for interface, or the interface will take
* care of the fragmentation for us, we can just send directly.
*/
if (ip_len <= mtu ||
(m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0) {
ip->ip_sum = 0;
if (m->m_pkthdr.csum_flags & CSUM_IP & ~ifp->if_hwassist) {
ip->ip_sum = in_cksum(m, hlen);
m->m_pkthdr.csum_flags &= ~CSUM_IP;
}
/*
* Record statistics for this interface address.
* With CSUM_TSO the byte/packet count will be slightly
* incorrect because we count the IP+TCP headers only
* once instead of for every generated packet.
*/
if (!(flags & IP_FORWARDING) && ia) {
if (m->m_pkthdr.csum_flags & CSUM_TSO)
counter_u64_add(ia->ia_ifa.ifa_opackets,
m->m_pkthdr.len / m->m_pkthdr.tso_segsz);
else
counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
counter_u64_add(ia->ia_ifa.ifa_obytes, m->m_pkthdr.len);
}
#ifdef MBUF_STRESS_TEST
if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
m = m_fragment(m, M_NOWAIT, mbuf_frag_size);
#endif
/*
* Reset layer specific mbuf flags
* to avoid confusing lower layers.
*/
m_clrprotoflags(m);
IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
error = ip_output_send(inp, ifp, m, gw, ro,
(flags & IP_NO_SND_TAG_RL) ? false : true);
goto done;
}
/* Balk when DF bit is set or the interface didn't support TSO. */
if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
error = EMSGSIZE;
IPSTAT_INC(ips_cantfrag);
goto bad;
}
/*
* Too large for interface; fragment if possible. If successful,
* on return, m will point to a list of packets to be sent.
*/
error = ip_fragment(ip, &m, mtu, ifp->if_hwassist);
if (error)
goto bad;
for (; m; m = m0) {
m0 = m->m_nextpkt;
m->m_nextpkt = 0;
if (error == 0) {
/* Record statistics for this interface address. */
if (ia != NULL) {
counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
counter_u64_add(ia->ia_ifa.ifa_obytes,
m->m_pkthdr.len);
}
/*
* Reset layer specific mbuf flags
* to avoid confusing upper layers.
*/
m_clrprotoflags(m);
IP_PROBE(send, NULL, NULL, mtod(m, struct ip *), ifp,
mtod(m, struct ip *), NULL);
error = ip_output_send(inp, ifp, m, gw, ro, true);
} else
m_freem(m);
}
if (error == 0)
IPSTAT_INC(ips_fragmented);
done:
return (error);
bad:
m_freem(m);
goto done;
}
/*
* Create a chain of fragments which fit the given mtu. m_frag points to the
* mbuf to be fragmented; on return it points to the chain with the fragments.
* Return 0 if no error. If error, m_frag may contain a partially built
* chain of fragments that should be freed by the caller.
*
* if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
*/
int
ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
u_long if_hwassist_flags)
{
int error = 0;
int hlen = ip->ip_hl << 2;
int len = (mtu - hlen) & ~7; /* size of payload in each fragment */
int off;
struct mbuf *m0 = *m_frag; /* the original packet */
int firstlen;
struct mbuf **mnext;
int nfrags;
uint16_t ip_len, ip_off;
ip_len = ntohs(ip->ip_len);
ip_off = ntohs(ip->ip_off);
if (ip_off & IP_DF) { /* Fragmentation not allowed */
IPSTAT_INC(ips_cantfrag);
return EMSGSIZE;
}
/*
* Must be able to put at least 8 bytes per fragment.
*/
if (len < 8)
return EMSGSIZE;
/*
* If the interface will not calculate checksums on
* fragmented packets, then do it here.
*/
if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
m0 = mb_unmapped_to_ext(m0);
if (m0 == NULL) {
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
goto done;
}
in_delayed_cksum(m0);
m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
}
#ifdef SCTP
if (m0->m_pkthdr.csum_flags & CSUM_SCTP) {
m0 = mb_unmapped_to_ext(m0);
if (m0 == NULL) {
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
goto done;
}
sctp_delayed_cksum(m0, hlen);
m0->m_pkthdr.csum_flags &= ~CSUM_SCTP;
}
#endif
if (len > PAGE_SIZE) {
/*
* Fragment large datagrams such that each segment
* contains a multiple of PAGE_SIZE amount of data,
* plus headers. This enables a receiver to perform
* page-flipping zero-copy optimizations.
*
* XXX When does this help given that sender and receiver
* could have different page sizes, and also mtu could
* be less than the receiver's page size ?
*/
int newlen;
off = MIN(mtu, m0->m_pkthdr.len);
/*
* firstlen (off - hlen) must be aligned on an
* 8-byte boundary
*/
if (off < hlen)
goto smart_frag_failure;
off = ((off - hlen) & ~7) + hlen;
newlen = (~PAGE_MASK) & mtu;
if ((newlen + sizeof (struct ip)) > mtu) {
/* we failed, go back the default */
smart_frag_failure:
newlen = len;
off = hlen + len;
}
len = newlen;
} else {
off = hlen + len;
}
firstlen = off - hlen;
mnext = &m0->m_nextpkt; /* pointer to next packet */
/*
* Loop through length of segment after first fragment,
* make new header and copy data of each part and link onto chain.
* Here, m0 is the original packet, m is the fragment being created.
* The fragments are linked off the m_nextpkt of the original
* packet, which after processing serves as the first fragment.
*/
for (nfrags = 1; off < ip_len; off += len, nfrags++) {
struct ip *mhip; /* ip header on the fragment */
struct mbuf *m;
int mhlen = sizeof (struct ip);
m = m_gethdr(M_NOWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
goto done;
}
/*
* Make sure the complete packet header gets copied
* from the originating mbuf to the newly created
* mbuf. This also ensures that existing firewall
* classification(s), VLAN tags and so on get copied
* to the resulting fragmented packet(s):
*/
if (m_dup_pkthdr(m, m0, M_NOWAIT) == 0) {
m_free(m);
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
goto done;
}
/*
* In the first mbuf, leave room for the link header, then
* copy the original IP header including options. The payload
* goes into an additional mbuf chain returned by m_copym().
*/
m->m_data += max_linkhdr;
mhip = mtod(m, struct ip *);
*mhip = *ip;
if (hlen > sizeof (struct ip)) {
mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
mhip->ip_v = IPVERSION;
mhip->ip_hl = mhlen >> 2;
}
m->m_len = mhlen;
/* XXX do we need to add ip_off below ? */
mhip->ip_off = ((off - hlen) >> 3) + ip_off;
if (off + len >= ip_len)
len = ip_len - off;
else
mhip->ip_off |= IP_MF;
mhip->ip_len = htons((u_short)(len + mhlen));
m->m_next = m_copym(m0, off, len, M_NOWAIT);
if (m->m_next == NULL) { /* copy failed */
m_free(m);
error = ENOBUFS; /* ??? */
IPSTAT_INC(ips_odropped);
goto done;
}
m->m_pkthdr.len = mhlen + len;
#ifdef MAC
mac_netinet_fragment(m0, m);
#endif
mhip->ip_off = htons(mhip->ip_off);
mhip->ip_sum = 0;
if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
mhip->ip_sum = in_cksum(m, mhlen);
m->m_pkthdr.csum_flags &= ~CSUM_IP;
}
*mnext = m;
mnext = &m->m_nextpkt;
}
IPSTAT_ADD(ips_ofragments, nfrags);
/*
* Update first fragment by trimming what's been copied out
* and updating header.
*/
m_adj(m0, hlen + firstlen - ip_len);
m0->m_pkthdr.len = hlen + firstlen;
ip->ip_len = htons((u_short)m0->m_pkthdr.len);
ip->ip_off = htons(ip_off | IP_MF);
ip->ip_sum = 0;
if (m0->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
ip->ip_sum = in_cksum(m0, hlen);
m0->m_pkthdr.csum_flags &= ~CSUM_IP;
}
done:
*m_frag = m0;
return error;
}
void
in_delayed_cksum(struct mbuf *m)
{
struct ip *ip;
struct udphdr *uh;
uint16_t cklen, csum, offset;
ip = mtod(m, struct ip *);
offset = ip->ip_hl << 2 ;
if (m->m_pkthdr.csum_flags & CSUM_UDP) {
/* if udp header is not in the first mbuf copy udplen */
if (offset + sizeof(struct udphdr) > m->m_len) {
m_copydata(m, offset + offsetof(struct udphdr,
uh_ulen), sizeof(cklen), (caddr_t)&cklen);
cklen = ntohs(cklen);
} else {
uh = (struct udphdr *)mtodo(m, offset);
cklen = ntohs(uh->uh_ulen);
}
csum = in_cksum_skip(m, cklen + offset, offset);
if (csum == 0)
csum = 0xffff;
} else {
cklen = ntohs(ip->ip_len);
csum = in_cksum_skip(m, cklen, offset);
}
offset += m->m_pkthdr.csum_data; /* checksum offset */
if (offset + sizeof(csum) > m->m_len)
m_copyback(m, offset, sizeof(csum), (caddr_t)&csum);
else
*(u_short *)mtodo(m, offset) = csum;
}
/*
* IP socket option processing.
*/
int
ip_ctloutput(struct socket *so, struct sockopt *sopt)
{
struct inpcb *inp = sotoinpcb(so);
int error, optval;
#ifdef RSS
uint32_t rss_bucket;
int retval;
#endif
error = optval = 0;
if (sopt->sopt_level != IPPROTO_IP) {
error = EINVAL;
if (sopt->sopt_level == SOL_SOCKET &&
sopt->sopt_dir == SOPT_SET) {
switch (sopt->sopt_name) {
case SO_REUSEADDR:
INP_WLOCK(inp);
if ((so->so_options & SO_REUSEADDR) != 0)
inp->inp_flags2 |= INP_REUSEADDR;
else
inp->inp_flags2 &= ~INP_REUSEADDR;
INP_WUNLOCK(inp);
error = 0;
break;
case SO_REUSEPORT:
INP_WLOCK(inp);
if ((so->so_options & SO_REUSEPORT) != 0)
inp->inp_flags2 |= INP_REUSEPORT;
else
inp->inp_flags2 &= ~INP_REUSEPORT;
INP_WUNLOCK(inp);
error = 0;
break;
case SO_REUSEPORT_LB:
INP_WLOCK(inp);
if ((so->so_options & SO_REUSEPORT_LB) != 0)
inp->inp_flags2 |= INP_REUSEPORT_LB;
else
inp->inp_flags2 &= ~INP_REUSEPORT_LB;
INP_WUNLOCK(inp);
error = 0;
break;
case SO_SETFIB:
INP_WLOCK(inp);
inp->inp_inc.inc_fibnum = so->so_fibnum;
INP_WUNLOCK(inp);
error = 0;
break;
case SO_MAX_PACING_RATE:
#ifdef RATELIMIT
INP_WLOCK(inp);
inp->inp_flags2 |= INP_RATE_LIMIT_CHANGED;
INP_WUNLOCK(inp);
error = 0;
#else
error = EOPNOTSUPP;
#endif
break;
default:
break;
}
}
return (error);
}
switch (sopt->sopt_dir) {
case SOPT_SET:
switch (sopt->sopt_name) {
case IP_OPTIONS:
#ifdef notyet
case IP_RETOPTS:
#endif
{
struct mbuf *m;
if (sopt->sopt_valsize > MLEN) {
error = EMSGSIZE;
break;
}
m = m_get(sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
break;
}
m->m_len = sopt->sopt_valsize;
error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
m->m_len);
if (error) {
m_free(m);
break;
}
INP_WLOCK(inp);
error = ip_pcbopts(inp, sopt->sopt_name, m);
INP_WUNLOCK(inp);
return (error);
}
case IP_BINDANY:
if (sopt->sopt_td != NULL) {
error = priv_check(sopt->sopt_td,
PRIV_NETINET_BINDANY);
if (error)
break;
}
/* FALLTHROUGH */
case IP_BINDMULTI:
#ifdef RSS
case IP_RSS_LISTEN_BUCKET:
#endif
case IP_TOS:
case IP_TTL:
case IP_MINTTL:
case IP_RECVOPTS:
case IP_RECVRETOPTS:
case IP_ORIGDSTADDR:
case IP_RECVDSTADDR:
case IP_RECVTTL:
case IP_RECVIF:
case IP_ONESBCAST:
case IP_DONTFRAG:
case IP_RECVTOS:
case IP_RECVFLOWID:
#ifdef RSS
case IP_RECVRSSBUCKETID:
#endif
error = sooptcopyin(sopt, &optval, sizeof optval,
sizeof optval);
if (error)
break;
switch (sopt->sopt_name) {
case IP_TOS:
inp->inp_ip_tos = optval;
break;
case IP_TTL:
inp->inp_ip_ttl = optval;
break;
case IP_MINTTL:
if (optval >= 0 && optval <= MAXTTL)
inp->inp_ip_minttl = optval;
else
error = EINVAL;
break;
#define OPTSET(bit) do { \
INP_WLOCK(inp); \
if (optval) \
inp->inp_flags |= bit; \
else \
inp->inp_flags &= ~bit; \
INP_WUNLOCK(inp); \
} while (0)
#define OPTSET2(bit, val) do { \
INP_WLOCK(inp); \
if (val) \
inp->inp_flags2 |= bit; \
else \
inp->inp_flags2 &= ~bit; \
INP_WUNLOCK(inp); \
} while (0)
case IP_RECVOPTS:
OPTSET(INP_RECVOPTS);
break;
case IP_RECVRETOPTS:
OPTSET(INP_RECVRETOPTS);
break;
case IP_RECVDSTADDR:
OPTSET(INP_RECVDSTADDR);
break;
case IP_ORIGDSTADDR:
OPTSET2(INP_ORIGDSTADDR, optval);
break;
case IP_RECVTTL:
OPTSET(INP_RECVTTL);
break;
case IP_RECVIF:
OPTSET(INP_RECVIF);
break;
case IP_ONESBCAST:
OPTSET(INP_ONESBCAST);
break;
case IP_DONTFRAG:
OPTSET(INP_DONTFRAG);
break;
case IP_BINDANY:
OPTSET(INP_BINDANY);
break;
case IP_RECVTOS:
OPTSET(INP_RECVTOS);
break;
case IP_BINDMULTI:
OPTSET2(INP_BINDMULTI, optval);
break;
case IP_RECVFLOWID:
OPTSET2(INP_RECVFLOWID, optval);
break;
#ifdef RSS
case IP_RSS_LISTEN_BUCKET:
if ((optval >= 0) &&
(optval < rss_getnumbuckets())) {
inp->inp_rss_listen_bucket = optval;
OPTSET2(INP_RSS_BUCKET_SET, 1);
} else {
error = EINVAL;
}
break;
case IP_RECVRSSBUCKETID:
OPTSET2(INP_RECVRSSBUCKETID, optval);
break;
#endif
}
break;
#undef OPTSET
#undef OPTSET2
/*
* Multicast socket options are processed by the in_mcast
* module.
*/
case IP_MULTICAST_IF:
case IP_MULTICAST_VIF:
case IP_MULTICAST_TTL:
case IP_MULTICAST_LOOP:
case IP_ADD_MEMBERSHIP:
case IP_DROP_MEMBERSHIP:
case IP_ADD_SOURCE_MEMBERSHIP:
case IP_DROP_SOURCE_MEMBERSHIP:
case IP_BLOCK_SOURCE:
case IP_UNBLOCK_SOURCE:
case IP_MSFILTER:
case MCAST_JOIN_GROUP:
case MCAST_LEAVE_GROUP:
case MCAST_JOIN_SOURCE_GROUP:
case MCAST_LEAVE_SOURCE_GROUP:
case MCAST_BLOCK_SOURCE:
case MCAST_UNBLOCK_SOURCE:
error = inp_setmoptions(inp, sopt);
break;
case IP_PORTRANGE:
error = sooptcopyin(sopt, &optval, sizeof optval,
sizeof optval);
if (error)
break;
INP_WLOCK(inp);
switch (optval) {
case IP_PORTRANGE_DEFAULT:
inp->inp_flags &= ~(INP_LOWPORT);
inp->inp_flags &= ~(INP_HIGHPORT);
break;
case IP_PORTRANGE_HIGH:
inp->inp_flags &= ~(INP_LOWPORT);
inp->inp_flags |= INP_HIGHPORT;
break;
case IP_PORTRANGE_LOW:
inp->inp_flags &= ~(INP_HIGHPORT);
inp->inp_flags |= INP_LOWPORT;
break;
default:
error = EINVAL;
break;
}
INP_WUNLOCK(inp);
break;
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
case IP_IPSEC_POLICY:
if (IPSEC_ENABLED(ipv4)) {
error = IPSEC_PCBCTL(ipv4, inp, sopt);
break;
}
/* FALLTHROUGH */
#endif /* IPSEC */
default:
error = ENOPROTOOPT;
break;
}
break;
case SOPT_GET:
switch (sopt->sopt_name) {
case IP_OPTIONS:
case IP_RETOPTS:
INP_RLOCK(inp);
if (inp->inp_options) {
struct mbuf *options;
options = m_copym(inp->inp_options, 0,
M_COPYALL, M_NOWAIT);
INP_RUNLOCK(inp);
if (options != NULL) {
error = sooptcopyout(sopt,
mtod(options, char *),
options->m_len);
m_freem(options);
} else
error = ENOMEM;
} else {
INP_RUNLOCK(inp);
sopt->sopt_valsize = 0;
}
break;
case IP_TOS:
case IP_TTL:
case IP_MINTTL:
case IP_RECVOPTS:
case IP_RECVRETOPTS:
case IP_ORIGDSTADDR:
case IP_RECVDSTADDR:
case IP_RECVTTL:
case IP_RECVIF:
case IP_PORTRANGE:
case IP_ONESBCAST:
case IP_DONTFRAG:
case IP_BINDANY:
case IP_RECVTOS:
case IP_BINDMULTI:
case IP_FLOWID:
case IP_FLOWTYPE:
case IP_RECVFLOWID:
#ifdef RSS
case IP_RSSBUCKETID:
case IP_RECVRSSBUCKETID:
#endif
switch (sopt->sopt_name) {
case IP_TOS:
optval = inp->inp_ip_tos;
break;
case IP_TTL:
optval = inp->inp_ip_ttl;
break;
case IP_MINTTL:
optval = inp->inp_ip_minttl;
break;
#define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)
#define OPTBIT2(bit) (inp->inp_flags2 & bit ? 1 : 0)
case IP_RECVOPTS:
optval = OPTBIT(INP_RECVOPTS);
break;
case IP_RECVRETOPTS:
optval = OPTBIT(INP_RECVRETOPTS);
break;
case IP_RECVDSTADDR:
optval = OPTBIT(INP_RECVDSTADDR);
break;
case IP_ORIGDSTADDR:
optval = OPTBIT2(INP_ORIGDSTADDR);
break;
case IP_RECVTTL:
optval = OPTBIT(INP_RECVTTL);
break;
case IP_RECVIF:
optval = OPTBIT(INP_RECVIF);
break;
case IP_PORTRANGE:
if (inp->inp_flags & INP_HIGHPORT)
optval = IP_PORTRANGE_HIGH;
else if (inp->inp_flags & INP_LOWPORT)
optval = IP_PORTRANGE_LOW;
else
optval = 0;
break;
case IP_ONESBCAST:
optval = OPTBIT(INP_ONESBCAST);
break;
case IP_DONTFRAG:
optval = OPTBIT(INP_DONTFRAG);
break;
case IP_BINDANY:
optval = OPTBIT(INP_BINDANY);
break;
case IP_RECVTOS:
optval = OPTBIT(INP_RECVTOS);
break;
case IP_FLOWID:
optval = inp->inp_flowid;
break;
case IP_FLOWTYPE:
optval = inp->inp_flowtype;
break;
case IP_RECVFLOWID:
optval = OPTBIT2(INP_RECVFLOWID);
break;
#ifdef RSS
case IP_RSSBUCKETID:
retval = rss_hash2bucket(inp->inp_flowid,
inp->inp_flowtype,
&rss_bucket);
if (retval == 0)
optval = rss_bucket;
else
error = EINVAL;
break;
case IP_RECVRSSBUCKETID:
optval = OPTBIT2(INP_RECVRSSBUCKETID);
break;
#endif
case IP_BINDMULTI:
optval = OPTBIT2(INP_BINDMULTI);
break;
}
error = sooptcopyout(sopt, &optval, sizeof optval);
break;
/*
* Multicast socket options are processed by the in_mcast
* module.
*/
case IP_MULTICAST_IF:
case IP_MULTICAST_VIF:
case IP_MULTICAST_TTL:
case IP_MULTICAST_LOOP:
case IP_MSFILTER:
error = inp_getmoptions(inp, sopt);
break;
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
case IP_IPSEC_POLICY:
if (IPSEC_ENABLED(ipv4)) {
error = IPSEC_PCBCTL(ipv4, inp, sopt);
break;
}
/* FALLTHROUGH */
#endif /* IPSEC */
default:
error = ENOPROTOOPT;
break;
}
break;
}
return (error);
}
/*
* Routine called from ip_output() to loop back a copy of an IP multicast
* packet to the input queue of a specified interface. Note that this
* calls the output routine of the loopback "driver", but with an interface
* pointer that might NOT be a loopback interface -- evil, but easier than
* replicating that code here.
*/
static void
ip_mloopback(struct ifnet *ifp, const struct mbuf *m, int hlen)
{
struct ip *ip;
struct mbuf *copym;
/*
* Make a deep copy of the packet because we're going to
* modify the pack in order to generate checksums.
*/
copym = m_dup(m, M_NOWAIT);
if (copym != NULL && (!M_WRITABLE(copym) || copym->m_len < hlen))
copym = m_pullup(copym, hlen);
if (copym != NULL) {
/* If needed, compute the checksum and mark it as valid. */
if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
in_delayed_cksum(copym);
copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
copym->m_pkthdr.csum_flags |=
CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
copym->m_pkthdr.csum_data = 0xffff;
}
/*
* We don't bother to fragment if the IP length is greater
* than the interface's MTU. Can this possibly matter?
*/
ip = mtod(copym, struct ip *);
ip->ip_sum = 0;
ip->ip_sum = in_cksum(copym, hlen);
if_simloop(ifp, copym, AF_INET, 0);
}
}
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