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8f134647ca
freebsd-nq/sys/netinet/ip_output.c
Gleb Smirnoff 8f134647ca Switch the entire IPv4 stack to keep the IP packet header 
in network byte order. Any host byte order processing is
done in local variables and host byte order values are
never[1] written to a packet.

  After this change a packet processed by the stack isn't
modified at all[2] except for TTL.

  After this change a network stack hacker doesn't need to
scratch his head trying to figure out what is the byte order
at the given place in the stack.

[1] One exception still remains. The raw sockets convert host
byte order before pass a packet to an application. Probably
this would remain for ages for compatibility.

[2] The ip_input() still subtructs header len from ip->ip_len,
but this is planned to be fixed soon.

Reviewed by:	luigi, Maxim Dounin <mdounin mdounin.ru>
Tested by:	ray, Olivier Cochard-Labbe <olivier cochard.me>
2012-10-22 21:09:03 +00:00

1327 lines
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/*-
* 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.
* 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.
*
* @(#)ip_output.c 8.3 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ipfw.h"
#include "opt_ipsec.h"
#include "opt_route.h"
#include "opt_mbuf_stress_test.h"
#include "opt_mpath.h"
#include "opt_sctp.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/ucred.h>
#include <net/if.h>
#include <net/if_llatbl.h>
#include <net/netisr.h>
#include <net/pfil.h>
#include <net/route.h>
#include <net/flowtable.h>
#ifdef RADIX_MPATH
#include <net/radix_mpath.h>
#endif
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#ifdef SCTP
#include <netinet/sctp.h>
#include <netinet/sctp_crc32.h>
#endif
#ifdef IPSEC
#include <netinet/ip_ipsec.h>
#include <netipsec/ipsec.h>
#endif /* IPSEC*/
#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>
VNET_DEFINE(u_short, ip_id);
#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 *, struct mbuf *, struct sockaddr_in *, int);
extern int in_mcast_loop;
extern struct protosw inetsw[];
/*
* 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 ip *ip;
struct ifnet *ifp = NULL; /* keep compiler happy */
struct mbuf *m0;
int hlen = sizeof (struct ip);
int mtu;
int n; /* scratchpad */
int error = 0;
struct sockaddr_in *dst;
struct in_ifaddr *ia;
int isbroadcast;
uint16_t ip_len, ip_off, sw_csum;
struct route iproute;
struct rtentry *rte; /* cache for ro->ro_rt */
struct in_addr odst;
#ifdef IPFIREWALL_FORWARD
struct m_tag *fwd_tag = NULL;
#endif
#ifdef IPSEC
int no_route_but_check_spd = 0;
#endif
M_ASSERTPKTHDR(m);
if (inp != NULL) {
INP_LOCK_ASSERT(inp);
M_SETFIB(m, inp->inp_inc.inc_fibnum);
if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) {
m->m_pkthdr.flowid = inp->inp_flowid;
m->m_flags |= M_FLOWID;
}
}
if (ro == NULL) {
ro = &iproute;
bzero(ro, sizeof (*ro));
}
#ifdef FLOWTABLE
if (ro->ro_rt == NULL) {
struct flentry *fle;
/*
* The flow table returns route entries valid for up to 30
* seconds; we rely on the remainder of ip_output() taking no
* longer than that long for the stability of ro_rt. The
* flow ID assignment must have happened before this point.
*/
fle = flowtable_lookup_mbuf(V_ip_ft, m, AF_INET);
if (fle != NULL)
flow_to_route(fle, ro);
}
#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);
/*
* Fill in IP header. If we are not allowing fragmentation,
* then the ip_id field is meaningless, but we don't set it
* to zero. Doing so causes various problems when devices along
* the path (routers, load balancers, firewalls, etc.) illegally
* disable DF on our packet. Note that a 16-bit counter
* will wrap around in less than 10 seconds at 100 Mbit/s on a
* medium with MTU 1500. See Steven M. Bellovin, "A Technique
* for Counting NATted Hosts", Proc. IMW'02, available at
* <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>.
*/
if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
ip->ip_v = IPVERSION;
ip->ip_hl = hlen >> 2;
ip->ip_id = ip_newid();
IPSTAT_INC(ips_localout);
} else {
/* Header already set, fetch hlen from there */
hlen = ip->ip_hl << 2;
}
dst = (struct sockaddr_in *)&ro->ro_dst;
again:
ia = NULL;
/*
* 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.
*/
rte = ro->ro_rt;
if (rte && ((rte->rt_flags & RTF_UP) == 0 ||
rte->rt_ifp == NULL ||
!RT_LINK_IS_UP(rte->rt_ifp) ||
dst->sin_family != AF_INET ||
dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
RO_RTFREE(ro);
ro->ro_lle = NULL;
rte = NULL;
}
#ifdef IPFIREWALL_FORWARD
if (rte == NULL && fwd_tag == NULL) {
#else
if (rte == NULL) {
#endif
bzero(dst, sizeof(*dst));
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = ip->ip_dst;
}
/*
* 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)))) == NULL &&
(ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 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;
ip->ip_ttl = 1;
isbroadcast = 1;
} else if (flags & IP_ROUTETOIF) {
if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
(ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0))) == NULL) {
IPSTAT_INC(ips_noroute);
error = ENETUNREACH;
goto bad;
}
ifp = ia->ia_ifp;
ip->ip_ttl = 1;
isbroadcast = in_broadcast(dst->sin_addr, ifp);
} 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;
IFP_TO_IA(ifp, ia);
isbroadcast = 0; /* fool gcc */
} else {
/*
* 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).
*/
if (rte == NULL) {
#ifdef RADIX_MPATH
rtalloc_mpath_fib(ro,
ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
#else
in_rtalloc_ign(ro, 0,
inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
#endif
rte = ro->ro_rt;
}
if (rte == NULL ||
rte->rt_ifp == NULL ||
!RT_LINK_IS_UP(rte->rt_ifp)) {
#ifdef IPSEC
/*
* 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(rte->rt_ifa);
ifa_ref(&ia->ia_ifa);
ifp = rte->rt_ifp;
rte->rt_rmx.rmx_pksent++;
if (rte->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in *)rte->rt_gateway;
if (rte->rt_flags & RTF_HOST)
isbroadcast = (rte->rt_flags & RTF_BROADCAST);
else
isbroadcast = in_broadcast(dst->sin_addr, ifp);
}
/*
* Calculate MTU. If we have a route that is up, use that,
* otherwise use the interface's MTU.
*/
if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) {
/*
* This case can happen if the user changed the MTU
* of an interface after enabling IP on it. Because
* most netifs don't keep track of routes pointing to
* them, there is no way for one to update all its
* routes when the MTU is changed.
*/
if (rte->rt_rmx.rmx_mtu > ifp->if_mtu)
rte->rt_rmx.rmx_mtu = ifp->if_mtu;
mtu = rte->rt_rmx.rmx_mtu;
} else {
mtu = ifp->if_mtu;
}
/* Catch a possible divide by zero later. */
KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p",
__func__, mtu, rte, (rte != NULL) ? rte->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 "dst"
* still points to the address in "ro". (It may have been
* changed to point to a gateway address, above.)
*/
dst = (struct sockaddr_in *)&ro->ro_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) {
/* Interface may have no addresses. */
if (ia != NULL)
ip->ip_src = IA_SIN(ia)->sin_addr;
}
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, dst, 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) {
/* Interface may have no addresses. */
if (ia != NULL) {
ip->ip_src = IA_SIN(ia)->sin_addr;
}
}
/*
* Verify that we have any chance at all of being able to queue the
* packet or packet fragments, unless ALTQ is enabled on the given
* interface in which case packetdrop should be done by queueing.
*/
n = ip_len / mtu + 1; /* how many fragments ? */
if (
#ifdef ALTQ
(!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
#endif /* ALTQ */
(ifp->if_snd.ifq_len + n) >= ifp->if_snd.ifq_maxlen ) {
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
ifp->if_snd.ifq_drops += n;
goto bad;
}
/*
* 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:
#ifdef IPSEC
switch(ip_ipsec_output(&m, inp, &flags, &error)) {
case 1:
goto bad;
case -1:
goto done;
case 0:
default:
break; /* Continue with packet processing. */
}
/*
* 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(&V_inet_pfil_hook))
goto passout;
/* Run through list of hooks for output packets. */
odst.s_addr = ip->ip_dst.s_addr;
error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp);
if (error != 0 || m == NULL)
goto done;
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);
goto done;
} else {
if (ia != NULL)
ifa_free(&ia->ia_ifa);
goto again; /* Redo the routing table lookup. */
}
}
#ifdef IPFIREWALL_FORWARD
/* 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);
goto done;
}
/* Or forward to some other address? */
fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
if (fwd_tag) {
dst = (struct sockaddr_in *)&ro->ro_dst;
bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
m->m_flags |= M_SKIP_FIREWALL;
m_tag_delete(m, fwd_tag);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
goto again;
}
#endif /* IPFIREWALL_FORWARD */
passout:
/* 127/8 must not appear on wire - RFC1122. */
if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
(ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
IPSTAT_INC(ips_badaddr);
error = EADDRNOTAVAIL;
goto bad;
}
}
m->m_pkthdr.csum_flags |= CSUM_IP;
sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
if (sw_csum & CSUM_DELAY_DATA) {
in_delayed_cksum(m);
sw_csum &= ~CSUM_DELAY_DATA;
}
#ifdef SCTP
if (sw_csum & CSUM_SCTP) {
sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
sw_csum &= ~CSUM_SCTP;
}
#endif
m->m_pkthdr.csum_flags &= ifp->if_hwassist;
/*
* 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_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) {
ip->ip_sum = 0;
if (sw_csum & CSUM_DELAY_IP)
ip->ip_sum = in_cksum(m, hlen);
/*
* 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)
ia->ia_ifa.if_opackets +=
m->m_pkthdr.len / m->m_pkthdr.tso_segsz;
else
ia->ia_ifa.if_opackets++;
ia->ia_ifa.if_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_DONTWAIT, mbuf_frag_size);
#endif
/*
* Reset layer specific mbuf flags
* to avoid confusing lower layers.
*/
m->m_flags &= ~(M_PROTOFLAGS);
error = (*ifp->if_output)(ifp, m,
(struct sockaddr *)dst, ro);
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, sw_csum);
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) {
ia->ia_ifa.if_opackets++;
ia->ia_ifa.if_obytes += m->m_pkthdr.len;
}
/*
* Reset layer specific mbuf flags
* to avoid confusing upper layers.
*/
m->m_flags &= ~(M_PROTOFLAGS);
error = (*ifp->if_output)(ifp, m,
(struct sockaddr *)dst, ro);
} else
m_freem(m);
}
if (error == 0)
IPSTAT_INC(ips_fragmented);
done:
if (ro == &iproute)
RO_RTFREE(ro);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
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)
* sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
*/
int
ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
u_long if_hwassist_flags, int sw_csum)
{
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 &&
(if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
in_delayed_cksum(m0);
m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
}
#ifdef SCTP
if (m0->m_pkthdr.csum_flags & CSUM_SCTP &&
(if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
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;
struct mbuf *m;
for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
off += m->m_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);
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
goto done;
}
m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
/*
* 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) { /* last fragment */
len = ip_len - off;
m->m_flags |= M_LASTFRAG;
} else
mhip->ip_off |= IP_MF;
mhip->ip_len = htons((u_short)(len + mhlen));
m->m_next = m_copym(m0, off, len, M_DONTWAIT);
if (m->m_next == NULL) { /* copy failed */
m_free(m);
error = ENOBUFS; /* ??? */
IPSTAT_INC(ips_odropped);
goto done;
}
m->m_pkthdr.len = mhlen + len;
m->m_pkthdr.rcvif = NULL;
#ifdef MAC
mac_netinet_fragment(m0, m);
#endif
m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
mhip->ip_off = htons(mhip->ip_off);
mhip->ip_sum = 0;
if (sw_csum & CSUM_DELAY_IP)
mhip->ip_sum = in_cksum(m, mhlen);
*mnext = m;
mnext = &m->m_nextpkt;
}
IPSTAT_ADD(ips_ofragments, nfrags);
/* set first marker for fragment chain */
m0->m_flags |= M_FIRSTFRAG | M_FRAG;
m0->m_pkthdr.csum_data = 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 (sw_csum & CSUM_DELAY_IP)
ip->ip_sum = in_cksum(m0, hlen);
done:
*m_frag = m0;
return error;
}
void
in_delayed_cksum(struct mbuf *m)
{
struct ip *ip;
uint16_t csum, offset, ip_len;
ip = mtod(m, struct ip *);
offset = ip->ip_hl << 2 ;
ip_len = ntohs(ip->ip_len);
csum = in_cksum_skip(m, ip_len, offset);
if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
csum = 0xffff;
offset += m->m_pkthdr.csum_data; /* checksum offset */
if (offset + sizeof(u_short) > m->m_len) {
printf("delayed m_pullup, m->len: %d off: %d p: %d\n",
m->m_len, offset, ip->ip_p);
/*
* XXX
* this shouldn't happen, but if it does, the
* correct behavior may be to insert the checksum
* in the appropriate next mbuf in the chain.
*/
return;
}
*(u_short *)(m->m_data + offset) = csum;
}
/*
* IP socket option processing.
*/
int
ip_ctloutput(struct socket *so, struct sockopt *sopt)
{
struct inpcb *inp = sotoinpcb(so);
int error, optval;
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 (IN_MULTICAST(ntohl(inp->inp_laddr.s_addr))) {
if ((so->so_options &
(SO_REUSEADDR | SO_REUSEPORT)) != 0)
inp->inp_flags2 |= INP_REUSEPORT;
else
inp->inp_flags2 &= ~INP_REUSEPORT;
}
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_SETFIB:
INP_WLOCK(inp);
inp->inp_inc.inc_fibnum = so->so_fibnum;
INP_WUNLOCK(inp);
error = 0;
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;
}
MGET(m, sopt->sopt_td ? M_WAIT : M_DONTWAIT, 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_TOS:
case IP_TTL:
case IP_MINTTL:
case IP_RECVOPTS:
case IP_RECVRETOPTS:
case IP_RECVDSTADDR:
case IP_RECVTTL:
case IP_RECVIF:
case IP_FAITH:
case IP_ONESBCAST:
case IP_DONTFRAG:
case IP_RECVTOS:
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)
case IP_RECVOPTS:
OPTSET(INP_RECVOPTS);
break;
case IP_RECVRETOPTS:
OPTSET(INP_RECVRETOPTS);
break;
case IP_RECVDSTADDR:
OPTSET(INP_RECVDSTADDR);
break;
case IP_RECVTTL:
OPTSET(INP_RECVTTL);
break;
case IP_RECVIF:
OPTSET(INP_RECVIF);
break;
case IP_FAITH:
OPTSET(INP_FAITH);
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;
}
break;
#undef OPTSET
/*
* 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;
#ifdef IPSEC
case IP_IPSEC_POLICY:
{
caddr_t req;
struct mbuf *m;
if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
break;
if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
break;
req = mtod(m, caddr_t);
error = ipsec_set_policy(inp, sopt->sopt_name, req,
m->m_len, (sopt->sopt_td != NULL) ?
sopt->sopt_td->td_ucred : NULL);
m_freem(m);
break;
}
#endif /* IPSEC */
default:
error = ENOPROTOOPT;
break;
}
break;
case SOPT_GET:
switch (sopt->sopt_name) {
case IP_OPTIONS:
case IP_RETOPTS:
if (inp->inp_options)
error = sooptcopyout(sopt,
mtod(inp->inp_options,
char *),
inp->inp_options->m_len);
else
sopt->sopt_valsize = 0;
break;
case IP_TOS:
case IP_TTL:
case IP_MINTTL:
case IP_RECVOPTS:
case IP_RECVRETOPTS:
case IP_RECVDSTADDR:
case IP_RECVTTL:
case IP_RECVIF:
case IP_PORTRANGE:
case IP_FAITH:
case IP_ONESBCAST:
case IP_DONTFRAG:
case IP_BINDANY:
case IP_RECVTOS:
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)
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_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_FAITH:
optval = OPTBIT(INP_FAITH);
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;
}
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;
#ifdef IPSEC
case IP_IPSEC_POLICY:
{
struct mbuf *m = NULL;
caddr_t req = NULL;
size_t len = 0;
if (m != 0) {
req = mtod(m, caddr_t);
len = m->m_len;
}
error = ipsec_get_policy(sotoinpcb(so), req, len, &m);
if (error == 0)
error = soopt_mcopyout(sopt, m); /* XXX */
if (error == 0)
m_freem(m);
break;
}
#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, struct mbuf *m, struct sockaddr_in *dst,
int hlen)
{
register 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_DONTWAIT);
if (copym != NULL && (copym->m_flags & M_EXT || 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 1 /* XXX */
if (dst->sin_family != AF_INET) {
printf("ip_mloopback: bad address family %d\n",
dst->sin_family);
dst->sin_family = AF_INET;
}
#endif
if_simloop(ifp, copym, dst->sin_family, 0);
}
}
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