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freebsd-nq/sys/netinet/ip_input.c
Robert Watson 36b0360b37 Introduce support for Mandatory Access Control and extensible 
kernel access control.

Instrument the code managing IP fragment reassembly queues (struct ipq)
to invoke appropriate MAC entry points to maintain a MAC label on
each queue.  Permit MAC policies to associate information with a queue
based on the mbuf that caused it to be created, update that information
based on further mbufs accepted by the queue, influence the decision
making process by which mbufs are accepted to the queue, and set the
label of the mbuf holding the reassembled datagram following reassembly
completetion.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-07-31 17:17:51 +00:00

1966 lines
50 KiB
C
Raw Blame History

/*
* Copyright (c) 1982, 1986, 1988, 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ip_input.c 8.2 (Berkeley) 1/4/94
* $FreeBSD$
*/
#define _IP_VHL
#include "opt_bootp.h"
#include "opt_ipfw.h"
#include "opt_ipdn.h"
#include "opt_ipdivert.h"
#include "opt_ipfilter.h"
#include "opt_ipstealth.h"
#include "opt_ipsec.h"
#include "opt_mac.h"
#include "opt_pfil_hooks.h"
#include "opt_random_ip_id.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mac.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <net/pfil.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/netisr.h>
#include <net/intrq.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <machine/in_cksum.h>
#include <sys/socketvar.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_dummynet.h>
#ifdef IPSEC
#include <netinet6/ipsec.h>
#include <netkey/key.h>
#endif
int rsvp_on = 0;
int ipforwarding = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
&ipforwarding, 0, "Enable IP forwarding between interfaces");
static int ipsendredirects = 1; /* XXX */
SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
&ipsendredirects, 0, "Enable sending IP redirects");
int ip_defttl = IPDEFTTL;
SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
&ip_defttl, 0, "Maximum TTL on IP packets");
static int ip_dosourceroute = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW,
&ip_dosourceroute, 0, "Enable forwarding source routed IP packets");
static int ip_acceptsourceroute = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute,
CTLFLAG_RW, &ip_acceptsourceroute, 0,
"Enable accepting source routed IP packets");
static int ip_keepfaith = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
&ip_keepfaith, 0,
"Enable packet capture for FAITH IPv4->IPv6 translater daemon");
static int ip_nfragpackets = 0;
static int ip_maxfragpackets; /* initialized in ip_init() */
SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW,
&ip_maxfragpackets, 0,
"Maximum number of IPv4 fragment reassembly queue entries");
/*
* XXX - Setting ip_checkinterface mostly implements the receive side of
* the Strong ES model described in RFC 1122, but since the routing table
* and transmit implementation do not implement the Strong ES model,
* setting this to 1 results in an odd hybrid.
*
* XXX - ip_checkinterface currently must be disabled if you use ipnat
* to translate the destination address to another local interface.
*
* XXX - ip_checkinterface must be disabled if you add IP aliases
* to the loopback interface instead of the interface where the
* packets for those addresses are received.
*/
static int ip_checkinterface = 1;
SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
&ip_checkinterface, 0, "Verify packet arrives on correct interface");
#ifdef DIAGNOSTIC
static int ipprintfs = 0;
#endif
static int ipqmaxlen = IFQ_MAXLEN;
extern struct domain inetdomain;
extern struct protosw inetsw[];
u_char ip_protox[IPPROTO_MAX];
struct in_ifaddrhead in_ifaddrhead; /* first inet address */
struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */
u_long in_ifaddrhmask; /* mask for hash table */
SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW,
&ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue");
SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD,
&ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue");
struct ipstat ipstat;
SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
&ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)");
/* Packet reassembly stuff */
#define IPREASS_NHASH_LOG2 6
#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
#define IPREASS_HMASK (IPREASS_NHASH - 1)
#define IPREASS_HASH(x,y) \
(((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH];
static int nipq = 0; /* total # of reass queues */
static int maxnipq;
#ifdef IPCTL_DEFMTU
SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
&ip_mtu, 0, "Default MTU");
#endif
#ifdef IPSTEALTH
static int ipstealth = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
&ipstealth, 0, "");
#endif
/* Firewall hooks */
ip_fw_chk_t *ip_fw_chk_ptr;
int fw_enable = 1 ;
/* Dummynet hooks */
ip_dn_io_t *ip_dn_io_ptr;
/*
* XXX this is ugly -- the following two global variables are
* used to store packet state while it travels through the stack.
* Note that the code even makes assumptions on the size and
* alignment of fields inside struct ip_srcrt so e.g. adding some
* fields will break the code. This needs to be fixed.
*
* We need to save the IP options in case a protocol wants to respond
* to an incoming packet over the same route if the packet got here
* using IP source routing. This allows connection establishment and
* maintenance when the remote end is on a network that is not known
* to us.
*/
static int ip_nhops = 0;
static struct ip_srcrt {
struct in_addr dst; /* final destination */
char nop; /* one NOP to align */
char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
} ip_srcrt;
static void save_rte(u_char *, struct in_addr);
static int ip_dooptions(struct mbuf *m, int,
struct sockaddr_in *next_hop);
static void ip_forward(struct mbuf *m, int srcrt,
struct sockaddr_in *next_hop);
static void ip_freef(struct ipqhead *, struct ipq *);
static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *,
struct ipq *, u_int32_t *, u_int16_t *);
static void ipintr(void);
/*
* IP initialization: fill in IP protocol switch table.
* All protocols not implemented in kernel go to raw IP protocol handler.
*/
void
ip_init()
{
register struct protosw *pr;
register int i;
TAILQ_INIT(&in_ifaddrhead);
in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask);
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == 0)
panic("ip_init");
for (i = 0; i < IPPROTO_MAX; i++)
ip_protox[i] = pr - inetsw;
for (pr = inetdomain.dom_protosw;
pr < inetdomain.dom_protoswNPROTOSW; pr++)
if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
ip_protox[pr->pr_protocol] = pr - inetsw;
for (i = 0; i < IPREASS_NHASH; i++)
TAILQ_INIT(&ipq[i]);
maxnipq = nmbclusters / 4;
ip_maxfragpackets = nmbclusters / 4;
#ifndef RANDOM_IP_ID
ip_id = time_second & 0xffff;
#endif
ipintrq.ifq_maxlen = ipqmaxlen;
mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF);
ipintrq_present = 1;
register_netisr(NETISR_IP, ipintr);
}
/*
* XXX watch out this one. It is perhaps used as a cache for
* the most recently used route ? it is cleared in in_addroute()
* when a new route is successfully created.
*/
struct route ipforward_rt;
/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassemble. Process options. Pass to next level.
*/
void
ip_input(struct mbuf *m)
{
struct ip *ip;
struct ipq *fp;
struct in_ifaddr *ia = NULL;
struct ifaddr *ifa;
int i, hlen, checkif;
u_short sum;
struct in_addr pkt_dst;
u_int32_t divert_info = 0; /* packet divert/tee info */
struct ip_fw_args args;
#ifdef PFIL_HOOKS
struct packet_filter_hook *pfh;
struct mbuf *m0;
int rv;
#endif /* PFIL_HOOKS */
args.eh = NULL;
args.oif = NULL;
args.rule = NULL;
args.divert_rule = 0; /* divert cookie */
args.next_hop = NULL;
/* Grab info from MT_TAG mbufs prepended to the chain. */
for (; m && m->m_type == MT_TAG; m = m->m_next) {
switch(m->m_tag_id) {
default:
printf("ip_input: unrecognised MT_TAG tag %d\n",
m->m_tag_id);
break;
case PACKET_TAG_DUMMYNET:
args.rule = ((struct dn_pkt *)m)->rule;
break;
case PACKET_TAG_DIVERT:
args.divert_rule = (intptr_t)m->m_hdr.mh_data & 0xffff;
break;
case PACKET_TAG_IPFORWARD:
args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data;
break;
}
}
KASSERT(m != NULL && (m->m_flags & M_PKTHDR) != 0,
("ip_input: no HDR"));
if (args.rule) { /* dummynet already filtered us */
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
goto iphack ;
}
ipstat.ips_total++;
if (m->m_pkthdr.len < sizeof(struct ip))
goto tooshort;
if (m->m_len < sizeof (struct ip) &&
(m = m_pullup(m, sizeof (struct ip))) == 0) {
ipstat.ips_toosmall++;
return;
}
ip = mtod(m, struct ip *);
if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
ipstat.ips_badvers++;
goto bad;
}
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
if (hlen < sizeof(struct ip)) { /* minimum header length */
ipstat.ips_badhlen++;
goto bad;
}
if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == 0) {
ipstat.ips_badhlen++;
return;
}
ip = mtod(m, struct ip *);
}
/* 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 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
ipstat.ips_badaddr++;
goto bad;
}
}
if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
} else {
if (hlen == sizeof(struct ip)) {
sum = in_cksum_hdr(ip);
} else {
sum = in_cksum(m, hlen);
}
}
if (sum) {
ipstat.ips_badsum++;
goto bad;
}
/*
* Convert fields to host representation.
*/
ip->ip_len = ntohs(ip->ip_len);
if (ip->ip_len < hlen) {
ipstat.ips_badlen++;
goto bad;
}
ip->ip_off = ntohs(ip->ip_off);
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len < ip->ip_len) {
tooshort:
ipstat.ips_tooshort++;
goto bad;
}
if (m->m_pkthdr.len > ip->ip_len) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip->ip_len;
m->m_pkthdr.len = ip->ip_len;
} else
m_adj(m, ip->ip_len - m->m_pkthdr.len);
}
#ifdef IPSEC
if (ipsec_gethist(m, NULL))
goto pass;
#endif
/*
* IpHack's section.
* Right now when no processing on packet has done
* and it is still fresh out of network we do our black
* deals with it.
* - Firewall: deny/allow/divert
* - Xlate: translate packet's addr/port (NAT).
* - Pipe: pass pkt through dummynet.
* - Wrap: fake packet's addr/port <unimpl.>
* - Encapsulate: put it in another IP and send out. <unimp.>
*/
iphack:
#ifdef PFIL_HOOKS
/*
* Run through list of hooks for input packets. If there are any
* filters which require that additional packets in the flow are
* not fast-forwarded, they must clear the M_CANFASTFWD flag.
* Note that filters must _never_ set this flag, as another filter
* in the list may have previously cleared it.
*/
m0 = m;
pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh);
for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link))
if (pfh->pfil_func) {
rv = pfh->pfil_func(ip, hlen,
m->m_pkthdr.rcvif, 0, &m0);
if (rv)
return;
m = m0;
if (m == NULL)
return;
ip = mtod(m, struct ip *);
}
#endif /* PFIL_HOOKS */
if (fw_enable && IPFW_LOADED) {
/*
* If we've been forwarded from the output side, then
* skip the firewall a second time
*/
if (args.next_hop)
goto ours;
args.m = m;
i = ip_fw_chk_ptr(&args);
m = args.m;
if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */
if (m)
m_freem(m);
return;
}
ip = mtod(m, struct ip *); /* just in case m changed */
if (i == 0 && args.next_hop == NULL) /* common case */
goto pass;
if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) {
/* Send packet to the appropriate pipe */
ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args);
return;
}
#ifdef IPDIVERT
if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) {
/* Divert or tee packet */
divert_info = i;
goto ours;
}
#endif
if (i == 0 && args.next_hop != NULL)
goto pass;
/*
* if we get here, the packet must be dropped
*/
m_freem(m);
return;
}
pass:
/*
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
* to be sent and the original packet to be freed).
*/
ip_nhops = 0; /* for source routed packets */
if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop))
return;
/* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
* matter if it is destined to another node, or whether it is
* a multicast one, RSVP wants it! and prevents it from being forwarded
* anywhere else. Also checks if the rsvp daemon is running before
* grabbing the packet.
*/
if (rsvp_on && ip->ip_p==IPPROTO_RSVP)
goto ours;
/*
* Check our list of addresses, to see if the packet is for us.
* If we don't have any addresses, assume any unicast packet
* we receive might be for us (and let the upper layers deal
* with it).
*/
if (TAILQ_EMPTY(&in_ifaddrhead) &&
(m->m_flags & (M_MCAST|M_BCAST)) == 0)
goto ours;
/*
* Cache the destination address of the packet; this may be
* changed by use of 'ipfw fwd'.
*/
pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
/*
* Enable a consistency check between the destination address
* and the arrival interface for a unicast packet (the RFC 1122
* strong ES model) if IP forwarding is disabled and the packet
* is not locally generated and the packet is not subject to
* 'ipfw fwd'.
*
* XXX - Checking also should be disabled if the destination
* address is ipnat'ed to a different interface.
*
* XXX - Checking is incompatible with IP aliases added
* to the loopback interface instead of the interface where
* the packets are received.
*/
checkif = ip_checkinterface && (ipforwarding == 0) &&
m->m_pkthdr.rcvif != NULL &&
((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
(args.next_hop == NULL);
/*
* Check for exact addresses in the hash bucket.
*/
LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) {
/*
* If the address matches, verify that the packet
* arrived via the correct interface if checking is
* enabled.
*/
if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
(!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
goto ours;
}
/*
* Check for broadcast addresses.
*
* Only accept broadcast packets that arrive via the matching
* interface. Reception of forwarded directed broadcasts would
* be handled via ip_forward() and ether_output() with the loopback
* into the stack for SIMPLEX interfaces handled by ether_output().
*/
if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
ia = ifatoia(ifa);
if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
pkt_dst.s_addr)
goto ours;
if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr)
goto ours;
#ifdef BOOTP_COMPAT
if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
goto ours;
#endif
}
}
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
struct in_multi *inm;
if (ip_mrouter) {
/*
* If we are acting as a multicast router, all
* incoming multicast packets are passed to the
* kernel-level multicast forwarding function.
* The packet is returned (relatively) intact; if
* ip_mforward() returns a non-zero value, the packet
* must be discarded, else it may be accepted below.
*/
if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) {
ipstat.ips_cantforward++;
m_freem(m);
return;
}
/*
* The process-level routing daemon needs to receive
* all multicast IGMP packets, whether or not this
* host belongs to their destination groups.
*/
if (ip->ip_p == IPPROTO_IGMP)
goto ours;
ipstat.ips_forward++;
}
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
if (inm == NULL) {
ipstat.ips_notmember++;
m_freem(m);
return;
}
goto ours;
}
if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
goto ours;
if (ip->ip_dst.s_addr == INADDR_ANY)
goto ours;
/*
* FAITH(Firewall Aided Internet Translator)
*/
if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
if (ip_keepfaith) {
if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
goto ours;
}
m_freem(m);
return;
}
/*
* Not for us; forward if possible and desirable.
*/
if (ipforwarding == 0) {
ipstat.ips_cantforward++;
m_freem(m);
} else {
#ifdef IPSEC
/*
* Enforce inbound IPsec SPD.
*/
if (ipsec4_in_reject(m, NULL)) {
ipsecstat.in_polvio++;
goto bad;
}
#endif /* IPSEC */
ip_forward(m, 0, args.next_hop);
}
return;
ours:
#ifdef IPSTEALTH
/*
* IPSTEALTH: Process non-routing options only
* if the packet is destined for us.
*/
if (ipstealth && hlen > sizeof (struct ip) &&
ip_dooptions(m, 1, args.next_hop))
return;
#endif /* IPSTEALTH */
/* Count the packet in the ip address stats */
if (ia != NULL) {
ia->ia_ifa.if_ipackets++;
ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
}
/*
* If offset or IP_MF are set, must reassemble.
* Otherwise, nothing need be done.
* (We could look in the reassembly queue to see
* if the packet was previously fragmented,
* but it's not worth the time; just let them time out.)
*/
if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
/*
* Look for queue of fragments
* of this datagram.
*/
TAILQ_FOREACH(fp, &ipq[sum], ipq_list)
if (ip->ip_id == fp->ipq_id &&
ip->ip_src.s_addr == fp->ipq_src.s_addr &&
ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
#ifdef MAC
mac_fragment_match(m, fp) &&
#endif
ip->ip_p == fp->ipq_p)
goto found;
fp = 0;
/* check if there's a place for the new queue */
if (nipq > maxnipq) {
/*
* drop something from the tail of the current queue
* before proceeding further
*/
struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead);
if (q == NULL) { /* gak */
for (i = 0; i < IPREASS_NHASH; i++) {
struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
if (r) {
ip_freef(&ipq[i], r);
break;
}
}
} else
ip_freef(&ipq[sum], q);
}
found:
/*
* Adjust ip_len to not reflect header,
* convert offset of this to bytes.
*/
ip->ip_len -= hlen;
if (ip->ip_off & IP_MF) {
/*
* Make sure that fragments have a data length
* that's a non-zero multiple of 8 bytes.
*/
if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
ipstat.ips_toosmall++; /* XXX */
goto bad;
}
m->m_flags |= M_FRAG;
}
ip->ip_off <<= 3;
/*
* Attempt reassembly; if it succeeds, proceed.
* ip_reass() will return a different mbuf, and update
* the divert info in divert_info and args.divert_rule.
*/
ipstat.ips_fragments++;
m->m_pkthdr.header = ip;
m = ip_reass(m,
&ipq[sum], fp, &divert_info, &args.divert_rule);
if (m == 0)
return;
ipstat.ips_reassembled++;
ip = mtod(m, struct ip *);
/* Get the header length of the reassembled packet */
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#ifdef IPDIVERT
/* Restore original checksum before diverting packet */
if (divert_info != 0) {
ip->ip_len += hlen;
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
ip->ip_sum = 0;
if (hlen == sizeof(struct ip))
ip->ip_sum = in_cksum_hdr(ip);
else
ip->ip_sum = in_cksum(m, hlen);
ip->ip_off = ntohs(ip->ip_off);
ip->ip_len = ntohs(ip->ip_len);
ip->ip_len -= hlen;
}
#endif
} else
ip->ip_len -= hlen;
#ifdef IPDIVERT
/*
* Divert or tee packet to the divert protocol if required.
*/
if (divert_info != 0) {
struct mbuf *clone = NULL;
/* Clone packet if we're doing a 'tee' */
if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0)
clone = m_dup(m, M_DONTWAIT);
/* Restore packet header fields to original values */
ip->ip_len += hlen;
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
/* Deliver packet to divert input routine */
divert_packet(m, 1, divert_info & 0xffff, args.divert_rule);
ipstat.ips_delivered++;
/* If 'tee', continue with original packet */
if (clone == NULL)
return;
m = clone;
ip = mtod(m, struct ip *);
ip->ip_len += hlen;
/*
* Jump backwards to complete processing of the
* packet. But first clear divert_info to avoid
* entering this block again.
* We do not need to clear args.divert_rule
* or args.next_hop as they will not be used.
*/
divert_info = 0;
goto pass;
}
#endif
#ifdef IPSEC
/*
* enforce IPsec policy checking if we are seeing last header.
* note that we do not visit this with protocols with pcb layer
* code - like udp/tcp/raw ip.
*/
if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
ipsec4_in_reject(m, NULL)) {
ipsecstat.in_polvio++;
goto bad;
}
#endif
/*
* Switch out to protocol's input routine.
*/
ipstat.ips_delivered++;
if (args.next_hop && ip->ip_p == IPPROTO_TCP) {
/* TCP needs IPFORWARD info if available */
struct m_hdr tag;
tag.mh_type = MT_TAG;
tag.mh_flags = PACKET_TAG_IPFORWARD;
tag.mh_data = (caddr_t)args.next_hop;
tag.mh_next = m;
(*inetsw[ip_protox[ip->ip_p]].pr_input)(
(struct mbuf *)&tag, hlen);
} else
(*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
return;
bad:
m_freem(m);
}
/*
* IP software interrupt routine - to go away sometime soon
*/
static void
ipintr(void)
{
struct mbuf *m;
while (1) {
IF_DEQUEUE(&ipintrq, m);
if (m == 0)
return;
ip_input(m);
}
}
/*
* Take incoming datagram fragment and try to reassemble it into
* whole datagram. If a chain for reassembly of this datagram already
* exists, then it is given as fp; otherwise have to make a chain.
*
* When IPDIVERT enabled, keep additional state with each packet that
* tells us if we need to divert or tee the packet we're building.
* In particular, *divinfo includes the port and TEE flag,
* *divert_rule is the number of the matching rule.
*/
static struct mbuf *
ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp,
u_int32_t *divinfo, u_int16_t *divert_rule)
{
struct ip *ip = mtod(m, struct ip *);
register struct mbuf *p, *q, *nq;
struct mbuf *t;
int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
int i, next;
/*
* Presence of header sizes in mbufs
* would confuse code below.
*/
m->m_data += hlen;
m->m_len -= hlen;
/*
* If first fragment to arrive, create a reassembly queue.
*/
if (fp == 0) {
/*
* Enforce upper bound on number of fragmented packets
* for which we attempt reassembly;
* If maxfrag is 0, never accept fragments.
* If maxfrag is -1, accept all fragments without limitation.
*/
if ((ip_maxfragpackets >= 0) && (ip_nfragpackets >= ip_maxfragpackets))
goto dropfrag;
ip_nfragpackets++;
if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
goto dropfrag;
fp = mtod(t, struct ipq *);
#ifdef MAC
mac_init_ipq(fp);
mac_create_ipq(m, fp);
#endif
TAILQ_INSERT_HEAD(head, fp, ipq_list);
nipq++;
fp->ipq_ttl = IPFRAGTTL;
fp->ipq_p = ip->ip_p;
fp->ipq_id = ip->ip_id;
fp->ipq_src = ip->ip_src;
fp->ipq_dst = ip->ip_dst;
fp->ipq_frags = m;
m->m_nextpkt = NULL;
#ifdef IPDIVERT
fp->ipq_div_info = 0;
fp->ipq_div_cookie = 0;
#endif
goto inserted;
} else {
#ifdef MAC
mac_update_ipq(m, fp);
#endif
}
#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
/*
* Find a segment which begins after this one does.
*/
for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
if (GETIP(q)->ip_off > ip->ip_off)
break;
/*
* If there is a preceding segment, it may provide some of
* our data already. If so, drop the data from the incoming
* segment. If it provides all of our data, drop us, otherwise
* stick new segment in the proper place.
*
* If some of the data is dropped from the the preceding
* segment, then it's checksum is invalidated.
*/
if (p) {
i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
if (i > 0) {
if (i >= ip->ip_len)
goto dropfrag;
m_adj(m, i);
m->m_pkthdr.csum_flags = 0;
ip->ip_off += i;
ip->ip_len -= i;
}
m->m_nextpkt = p->m_nextpkt;
p->m_nextpkt = m;
} else {
m->m_nextpkt = fp->ipq_frags;
fp->ipq_frags = m;
}
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
q = nq) {
i = (ip->ip_off + ip->ip_len) -
GETIP(q)->ip_off;
if (i < GETIP(q)->ip_len) {
GETIP(q)->ip_len -= i;
GETIP(q)->ip_off += i;
m_adj(q, i);
q->m_pkthdr.csum_flags = 0;
break;
}
nq = q->m_nextpkt;
m->m_nextpkt = nq;
m_freem(q);
}
inserted:
#ifdef IPDIVERT
/*
* Transfer firewall instructions to the fragment structure.
* Only trust info in the fragment at offset 0.
*/
if (ip->ip_off == 0) {
fp->ipq_div_info = *divinfo;
fp->ipq_div_cookie = *divert_rule;
}
*divinfo = 0;
*divert_rule = 0;
#endif
/*
* Check for complete reassembly.
*/
next = 0;
for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
if (GETIP(q)->ip_off != next)
return (0);
next += GETIP(q)->ip_len;
}
/* Make sure the last packet didn't have the IP_MF flag */
if (p->m_flags & M_FRAG)
return (0);
/*
* Reassembly is complete. Make sure the packet is a sane size.
*/
q = fp->ipq_frags;
ip = GETIP(q);
if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
ipstat.ips_toolong++;
ip_freef(head, fp);
return (0);
}
/*
* Concatenate fragments.
*/
m = q;
t = m->m_next;
m->m_next = 0;
m_cat(m, t);
nq = q->m_nextpkt;
q->m_nextpkt = 0;
for (q = nq; q != NULL; q = nq) {
nq = q->m_nextpkt;
q->m_nextpkt = NULL;
m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
m_cat(m, q);
}
#ifdef MAC
mac_create_datagram_from_ipq(fp, m);
mac_destroy_ipq(fp);
#endif
#ifdef IPDIVERT
/*
* Extract firewall instructions from the fragment structure.
*/
*divinfo = fp->ipq_div_info;
*divert_rule = fp->ipq_div_cookie;
#endif
/*
* Create header for new ip packet by
* modifying header of first packet;
* dequeue and discard fragment reassembly header.
* Make header visible.
*/
ip->ip_len = next;
ip->ip_src = fp->ipq_src;
ip->ip_dst = fp->ipq_dst;
TAILQ_REMOVE(head, fp, ipq_list);
nipq--;
(void) m_free(dtom(fp));
ip_nfragpackets--;
m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
/* some debugging cruft by sklower, below, will go away soon */
if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
register int plen = 0;
for (t = m; t; t = t->m_next)
plen += t->m_len;
m->m_pkthdr.len = plen;
}
return (m);
dropfrag:
#ifdef IPDIVERT
*divinfo = 0;
*divert_rule = 0;
#endif
ipstat.ips_fragdropped++;
m_freem(m);
return (0);
#undef GETIP
}
/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
static void
ip_freef(fhp, fp)
struct ipqhead *fhp;
struct ipq *fp;
{
register struct mbuf *q;
while (fp->ipq_frags) {
q = fp->ipq_frags;
fp->ipq_frags = q->m_nextpkt;
m_freem(q);
}
TAILQ_REMOVE(fhp, fp, ipq_list);
(void) m_free(dtom(fp));
ip_nfragpackets--;
nipq--;
}
/*
* IP timer processing;
* if a timer expires on a reassembly
* queue, discard it.
*/
void
ip_slowtimo()
{
register struct ipq *fp;
int s = splnet();
int i;
for (i = 0; i < IPREASS_NHASH; i++) {
for(fp = TAILQ_FIRST(&ipq[i]); fp;) {
struct ipq *fpp;
fpp = fp;
fp = TAILQ_NEXT(fp, ipq_list);
if(--fpp->ipq_ttl == 0) {
ipstat.ips_fragtimeout++;
ip_freef(&ipq[i], fpp);
}
}
}
/*
* If we are over the maximum number of fragments
* (due to the limit being lowered), drain off
* enough to get down to the new limit.
*/
for (i = 0; i < IPREASS_NHASH; i++) {
if (ip_maxfragpackets >= 0) {
while (ip_nfragpackets > ip_maxfragpackets &&
!TAILQ_EMPTY(&ipq[i])) {
ipstat.ips_fragdropped++;
ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
}
}
}
ipflow_slowtimo();
splx(s);
}
/*
* Drain off all datagram fragments.
*/
void
ip_drain()
{
int i;
for (i = 0; i < IPREASS_NHASH; i++) {
while(!TAILQ_EMPTY(&ipq[i])) {
ipstat.ips_fragdropped++;
ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
}
}
in_rtqdrain();
}
/*
* Do option processing on a datagram,
* possibly discarding it if bad options are encountered,
* or forwarding it if source-routed.
* The pass argument is used when operating in the IPSTEALTH
* mode to tell what options to process:
* [LS]SRR (pass 0) or the others (pass 1).
* The reason for as many as two passes is that when doing IPSTEALTH,
* non-routing options should be processed only if the packet is for us.
* Returns 1 if packet has been forwarded/freed,
* 0 if the packet should be processed further.
*/
static int
ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
{
struct ip *ip = mtod(m, struct ip *);
u_char *cp;
struct in_ifaddr *ia;
int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
struct in_addr *sin, dst;
n_time ntime;
struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
dst = ip->ip_dst;
cp = (u_char *)(ip + 1);
cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
else {
if (cnt < IPOPT_OLEN + sizeof(*cp)) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
optlen = cp[IPOPT_OLEN];
if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
}
switch (opt) {
default:
break;
/*
* Source routing with record.
* Find interface with current destination address.
* If none on this machine then drop if strictly routed,
* or do nothing if loosely routed.
* Record interface address and bring up next address
* component. If strictly routed make sure next
* address is on directly accessible net.
*/
case IPOPT_LSRR:
case IPOPT_SSRR:
#ifdef IPSTEALTH
if (ipstealth && pass > 0)
break;
#endif
if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
ipaddr.sin_addr = ip->ip_dst;
ia = (struct in_ifaddr *)
ifa_ifwithaddr((struct sockaddr *)&ipaddr);
if (ia == 0) {
if (opt == IPOPT_SSRR) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
if (!ip_dosourceroute)
goto nosourcerouting;
/*
* Loose routing, and not at next destination
* yet; nothing to do except forward.
*/
break;
}
off--; /* 0 origin */
if (off > optlen - (int)sizeof(struct in_addr)) {
/*
* End of source route. Should be for us.
*/
if (!ip_acceptsourceroute)
goto nosourcerouting;
save_rte(cp, ip->ip_src);
break;
}
#ifdef IPSTEALTH
if (ipstealth)
goto dropit;
#endif
if (!ip_dosourceroute) {
if (ipforwarding) {
char buf[16]; /* aaa.bbb.ccc.ddd\0 */
/*
* Acting as a router, so generate ICMP
*/
nosourcerouting:
strcpy(buf, inet_ntoa(ip->ip_dst));
log(LOG_WARNING,
"attempted source route from %s to %s\n",
inet_ntoa(ip->ip_src), buf);
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
} else {
/*
* Not acting as a router, so silently drop.
*/
#ifdef IPSTEALTH
dropit:
#endif
ipstat.ips_cantforward++;
m_freem(m);
return (1);
}
}
/*
* locate outgoing interface
*/
(void)memcpy(&ipaddr.sin_addr, cp + off,
sizeof(ipaddr.sin_addr));
if (opt == IPOPT_SSRR) {
#define INA struct in_ifaddr *
#define SA struct sockaddr *
if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
ia = (INA)ifa_ifwithnet((SA)&ipaddr);
} else
ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt);
if (ia == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
ip->ip_dst = ipaddr.sin_addr;
(void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
sizeof(struct in_addr));
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
/*
* Let ip_intr's mcast routing check handle mcast pkts
*/
forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
break;
case IPOPT_RR:
#ifdef IPSTEALTH
if (ipstealth && pass == 0)
break;
#endif
if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
/*
* If no space remains, ignore.
*/
off--; /* 0 origin */
if (off > optlen - (int)sizeof(struct in_addr))
break;
(void)memcpy(&ipaddr.sin_addr, &ip->ip_dst,
sizeof(ipaddr.sin_addr));
/*
* locate outgoing interface; if we're the destination,
* use the incoming interface (should be same).
*/
if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
(ia = ip_rtaddr(ipaddr.sin_addr,
&ipforward_rt)) == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
goto bad;
}
(void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
sizeof(struct in_addr));
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
break;
case IPOPT_TS:
#ifdef IPSTEALTH
if (ipstealth && pass == 0)
break;
#endif
code = cp - (u_char *)ip;
if (optlen < 4 || optlen > 40) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < 5) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
if (off > optlen - (int)sizeof(int32_t)) {
cp[IPOPT_OFFSET + 1] += (1 << 4);
if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
break;
}
off--; /* 0 origin */
sin = (struct in_addr *)(cp + off);
switch (cp[IPOPT_OFFSET + 1] & 0x0f) {
case IPOPT_TS_TSONLY:
break;
case IPOPT_TS_TSANDADDR:
if (off + sizeof(n_time) +
sizeof(struct in_addr) > optlen) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
ipaddr.sin_addr = dst;
ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
m->m_pkthdr.rcvif);
if (ia == 0)
continue;
(void)memcpy(sin, &IA_SIN(ia)->sin_addr,
sizeof(struct in_addr));
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
break;
case IPOPT_TS_PRESPEC:
if (off + sizeof(n_time) +
sizeof(struct in_addr) > optlen) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
(void)memcpy(&ipaddr.sin_addr, sin,
sizeof(struct in_addr));
if (ifa_ifwithaddr((SA)&ipaddr) == 0)
continue;
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
break;
default:
code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip;
goto bad;
}
ntime = iptime();
(void)memcpy(cp + off, &ntime, sizeof(n_time));
cp[IPOPT_OFFSET] += sizeof(n_time);
}
}
if (forward && ipforwarding) {
ip_forward(m, 1, next_hop);
return (1);
}
return (0);
bad:
icmp_error(m, type, code, 0, 0);
ipstat.ips_badoptions++;
return (1);
}
/*
* Given address of next destination (final or next hop),
* return internet address info of interface to be used to get there.
*/
struct in_ifaddr *
ip_rtaddr(dst, rt)
struct in_addr dst;
struct route *rt;
{
register struct sockaddr_in *sin;
sin = (struct sockaddr_in *)&rt->ro_dst;
if (rt->ro_rt == 0 ||
!(rt->ro_rt->rt_flags & RTF_UP) ||
dst.s_addr != sin->sin_addr.s_addr) {
if (rt->ro_rt) {
RTFREE(rt->ro_rt);
rt->ro_rt = 0;
}
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = dst;
rtalloc_ign(rt, RTF_PRCLONING);
}
if (rt->ro_rt == 0)
return ((struct in_ifaddr *)0);
return (ifatoia(rt->ro_rt->rt_ifa));
}
/*
* Save incoming source route for use in replies,
* to be picked up later by ip_srcroute if the receiver is interested.
*/
void
save_rte(option, dst)
u_char *option;
struct in_addr dst;
{
unsigned olen;
olen = option[IPOPT_OLEN];
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("save_rte: olen %d\n", olen);
#endif
if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
return;
bcopy(option, ip_srcrt.srcopt, olen);
ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
ip_srcrt.dst = dst;
}
/*
* Retrieve incoming source route for use in replies,
* in the same form used by setsockopt.
* The first hop is placed before the options, will be removed later.
*/
struct mbuf *
ip_srcroute()
{
register struct in_addr *p, *q;
register struct mbuf *m;
if (ip_nhops == 0)
return ((struct mbuf *)0);
m = m_get(M_DONTWAIT, MT_HEADER);
if (m == 0)
return ((struct mbuf *)0);
#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
OPTSIZ;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
#endif
/*
* First save first hop for return route
*/
p = &ip_srcrt.route[ip_nhops - 1];
*(mtod(m, struct in_addr *)) = *p--;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr));
#endif
/*
* Copy option fields and padding (nop) to mbuf.
*/
ip_srcrt.nop = IPOPT_NOP;
ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
(void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr),
&ip_srcrt.nop, OPTSIZ);
q = (struct in_addr *)(mtod(m, caddr_t) +
sizeof(struct in_addr) + OPTSIZ);
#undef OPTSIZ
/*
* Record return path as an IP source route,
* reversing the path (pointers are now aligned).
*/
while (p >= ip_srcrt.route) {
#ifdef DIAGNOSTIC
if (ipprintfs)
printf(" %lx", (u_long)ntohl(q->s_addr));
#endif
*q++ = *p--;
}
/*
* Last hop goes to final destination.
*/
*q = ip_srcrt.dst;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf(" %lx\n", (u_long)ntohl(q->s_addr));
#endif
return (m);
}
/*
* Strip out IP options, at higher
* level protocol in the kernel.
* Second argument is buffer to which options
* will be moved, and return value is their length.
* XXX should be deleted; last arg currently ignored.
*/
void
ip_stripoptions(m, mopt)
register struct mbuf *m;
struct mbuf *mopt;
{
register int i;
struct ip *ip = mtod(m, struct ip *);
register caddr_t opts;
int olen;
olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
opts = (caddr_t)(ip + 1);
i = m->m_len - (sizeof (struct ip) + olen);
bcopy(opts + olen, opts, (unsigned)i);
m->m_len -= olen;
if (m->m_flags & M_PKTHDR)
m->m_pkthdr.len -= olen;
ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
}
u_char inetctlerrmap[PRC_NCMDS] = {
0, 0, 0, 0,
0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
EMSGSIZE, EHOSTUNREACH, 0, 0,
0, 0, 0, 0,
ENOPROTOOPT, ECONNREFUSED
};
/*
* Forward a packet. If some error occurs return the sender
* an icmp packet. Note we can't always generate a meaningful
* icmp message because icmp doesn't have a large enough repertoire
* of codes and types.
*
* If not forwarding, just drop the packet. This could be confusing
* if ipforwarding was zero but some routing protocol was advancing
* us as a gateway to somewhere. However, we must let the routing
* protocol deal with that.
*
* The srcrt parameter indicates whether the packet is being forwarded
* via a source route.
*/
static void
ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
{
struct ip *ip = mtod(m, struct ip *);
struct rtentry *rt;
int error, type = 0, code = 0;
struct mbuf *mcopy;
n_long dest;
struct in_addr pkt_dst;
struct ifnet *destifp;
#ifdef IPSEC
struct ifnet dummyifp;
#endif
dest = 0;
/*
* Cache the destination address of the packet; this may be
* changed by use of 'ipfw fwd'.
*/
pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("forward: src %lx dst %lx ttl %x\n",
(u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr,
ip->ip_ttl);
#endif
if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) {
ipstat.ips_cantforward++;
m_freem(m);
return;
}
#ifdef IPSTEALTH
if (!ipstealth) {
#endif
if (ip->ip_ttl <= IPTTLDEC) {
icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
dest, 0);
return;
}
#ifdef IPSTEALTH
}
#endif
if (ip_rtaddr(pkt_dst, &ipforward_rt) == 0) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
return;
} else
rt = ipforward_rt.ro_rt;
/*
* Save the IP header and at most 8 bytes of the payload,
* in case we need to generate an ICMP message to the src.
*
* XXX this can be optimized a lot by saving the data in a local
* buffer on the stack (72 bytes at most), and only allocating the
* mbuf if really necessary. The vast majority of the packets
* are forwarded without having to send an ICMP back (either
* because unnecessary, or because rate limited), so we are
* really we are wasting a lot of work here.
*
* We don't use m_copy() because it might return a reference
* to a shared cluster. Both this function and ip_output()
* assume exclusive access to the IP header in `m', so any
* data in a cluster may change before we reach icmp_error().
*/
MGET(mcopy, M_DONTWAIT, m->m_type);
if (mcopy != NULL) {
M_COPY_PKTHDR(mcopy, m);
mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8,
(int)ip->ip_len);
m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
}
#ifdef IPSTEALTH
if (!ipstealth) {
#endif
ip->ip_ttl -= IPTTLDEC;
#ifdef IPSTEALTH
}
#endif
/*
* If forwarding packet using same interface that it came in on,
* perhaps should send a redirect to sender to shortcut a hop.
* Only send redirect if source is sending directly to us,
* and if packet was not source routed (or has any options).
* Also, don't send redirect if forwarding using a default route
* or a route modified by a redirect.
*/
if (rt->rt_ifp == m->m_pkthdr.rcvif &&
(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
ipsendredirects && !srcrt && !next_hop) {
#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
u_long src = ntohl(ip->ip_src.s_addr);
if (RTA(rt) &&
(src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
if (rt->rt_flags & RTF_GATEWAY)
dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
else
dest = pkt_dst.s_addr;
/* Router requirements says to only send host redirects */
type = ICMP_REDIRECT;
code = ICMP_REDIRECT_HOST;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("redirect (%d) to %lx\n", code, (u_long)dest);
#endif
}
}
error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
IP_FORWARDING, 0);
if (error)
ipstat.ips_cantforward++;
else {
ipstat.ips_forward++;
if (type)
ipstat.ips_redirectsent++;
else {
if (mcopy) {
ipflow_create(&ipforward_rt, mcopy);
m_freem(mcopy);
}
return;
}
}
if (mcopy == NULL)
return;
destifp = NULL;
switch (error) {
case 0: /* forwarded, but need redirect */
/* type, code set above */
break;
case ENETUNREACH: /* shouldn't happen, checked above */
case EHOSTUNREACH:
case ENETDOWN:
case EHOSTDOWN:
default:
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
break;
case EMSGSIZE:
type = ICMP_UNREACH;
code = ICMP_UNREACH_NEEDFRAG;
#ifndef IPSEC
if (ipforward_rt.ro_rt)
destifp = ipforward_rt.ro_rt->rt_ifp;
#else
/*
* If the packet is routed over IPsec tunnel, tell the
* originator the tunnel MTU.
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
* XXX quickhack!!!
*/
if (ipforward_rt.ro_rt) {
struct secpolicy *sp = NULL;
int ipsecerror;
int ipsechdr;
struct route *ro;
sp = ipsec4_getpolicybyaddr(mcopy,
IPSEC_DIR_OUTBOUND,
IP_FORWARDING,
&ipsecerror);
if (sp == NULL)
destifp = ipforward_rt.ro_rt->rt_ifp;
else {
/* count IPsec header size */
ipsechdr = ipsec4_hdrsiz(mcopy,
IPSEC_DIR_OUTBOUND,
NULL);
/*
* find the correct route for outer IPv4
* header, compute tunnel MTU.
*
* XXX BUG ALERT
* The "dummyifp" code relies upon the fact
* that icmp_error() touches only ifp->if_mtu.
*/
/*XXX*/
destifp = NULL;
if (sp->req != NULL
&& sp->req->sav != NULL
&& sp->req->sav->sah != NULL) {
ro = &sp->req->sav->sah->sa_route;
if (ro->ro_rt && ro->ro_rt->rt_ifp) {
dummyifp.if_mtu =
ro->ro_rt->rt_ifp->if_mtu;
dummyifp.if_mtu -= ipsechdr;
destifp = &dummyifp;
}
}
key_freesp(sp);
}
}
#endif /*IPSEC*/
ipstat.ips_cantfrag++;
break;
case ENOBUFS:
type = ICMP_SOURCEQUENCH;
code = 0;
break;
case EACCES: /* ipfw denied packet */
m_freem(mcopy);
return;
}
icmp_error(mcopy, type, code, dest, destifp);
}
void
ip_savecontrol(inp, mp, ip, m)
register struct inpcb *inp;
register struct mbuf **mp;
register struct ip *ip;
register struct mbuf *m;
{
if (inp->inp_socket->so_options & SO_TIMESTAMP) {
struct timeval tv;
microtime(&tv);
*mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
SCM_TIMESTAMP, SOL_SOCKET);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_flags & INP_RECVDSTADDR) {
*mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#ifdef notyet
/* XXX
* Moving these out of udp_input() made them even more broken
* than they already were.
*/
/* options were tossed already */
if (inp->inp_flags & INP_RECVOPTS) {
*mp = sbcreatecontrol((caddr_t) opts_deleted_above,
sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
/* ip_srcroute doesn't do what we want here, need to fix */
if (inp->inp_flags & INP_RECVRETOPTS) {
*mp = sbcreatecontrol((caddr_t) ip_srcroute(),
sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#endif
if (inp->inp_flags & INP_RECVIF) {
struct ifnet *ifp;
struct sdlbuf {
struct sockaddr_dl sdl;
u_char pad[32];
} sdlbuf;
struct sockaddr_dl *sdp;
struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
if (((ifp = m->m_pkthdr.rcvif))
&& ( ifp->if_index && (ifp->if_index <= if_index))) {
sdp = (struct sockaddr_dl *)
(ifaddr_byindex(ifp->if_index)->ifa_addr);
/*
* Change our mind and don't try copy.
*/
if ((sdp->sdl_family != AF_LINK)
|| (sdp->sdl_len > sizeof(sdlbuf))) {
goto makedummy;
}
bcopy(sdp, sdl2, sdp->sdl_len);
} else {
makedummy:
sdl2->sdl_len
= offsetof(struct sockaddr_dl, sdl_data[0]);
sdl2->sdl_family = AF_LINK;
sdl2->sdl_index = 0;
sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
}
*mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
IP_RECVIF, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
}
/*
* XXX these routines are called from the upper part of the kernel.
* They need to be locked when we remove Giant.
*
* They could also be moved to ip_mroute.c, since all the RSVP
* handling is done there already.
*/
static int ip_rsvp_on;
struct socket *ip_rsvpd;
int
ip_rsvp_init(struct socket *so)
{
if (so->so_type != SOCK_RAW ||
so->so_proto->pr_protocol != IPPROTO_RSVP)
return EOPNOTSUPP;
if (ip_rsvpd != NULL)
return EADDRINUSE;
ip_rsvpd = so;
/*
* This may seem silly, but we need to be sure we don't over-increment
* the RSVP counter, in case something slips up.
*/
if (!ip_rsvp_on) {
ip_rsvp_on = 1;
rsvp_on++;
}
return 0;
}
int
ip_rsvp_done(void)
{
ip_rsvpd = NULL;
/*
* This may seem silly, but we need to be sure we don't over-decrement
* the RSVP counter, in case something slips up.
*/
if (ip_rsvp_on) {
ip_rsvp_on = 0;
rsvp_on--;
}
return 0;
}
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