freebsd-dev/sys/netinet/ip_input.c
Luiz Otavio O Souza de89d74b70 Do not overwrite the dchg variable.
It does not cause any real issues because the variable is overwritten
only when the packet is forwarded (and the variable is not used anymore).

Obtained from:	pfSense
MFC after:	2 weeks
Sponsored by:	Rubicon Communications (Netgate)
2016-04-14 18:57:30 +00:00

1344 lines
35 KiB
C

/*-
* 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.
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_bootp.h"
#include "opt_ipfw.h"
#include "opt_ipstealth.h"
#include "opt_ipsec.h"
#include "opt_route.h"
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/hhook.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/lock.h>
#include <sys/rmlock.h>
#include <sys/rwlock.h>
#include <sys/sdt.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/rss_config.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_kdtrace.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_fw.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_options.h>
#include <machine/in_cksum.h>
#include <netinet/ip_carp.h>
#ifdef IPSEC
#include <netinet/ip_ipsec.h>
#include <netipsec/ipsec.h>
#include <netipsec/key.h>
#endif /* IPSEC */
#include <netinet/in_rss.h>
#include <sys/socketvar.h>
#include <security/mac/mac_framework.h>
#ifdef CTASSERT
CTASSERT(sizeof(struct ip) == 20);
#endif
/* IP reassembly functions are defined in ip_reass.c. */
extern void ipreass_init(void);
extern void ipreass_drain(void);
extern void ipreass_slowtimo(void);
#ifdef VIMAGE
extern void ipreass_destroy(void);
#endif
struct rmlock in_ifaddr_lock;
RM_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock");
VNET_DEFINE(int, rsvp_on);
VNET_DEFINE(int, ipforwarding);
SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(ipforwarding), 0,
"Enable IP forwarding between interfaces");
static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */
#define V_ipsendredirects VNET(ipsendredirects)
SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(ipsendredirects), 0,
"Enable sending IP redirects");
/*
* 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 VNET_DEFINE(int, ip_checkinterface);
#define V_ip_checkinterface VNET(ip_checkinterface)
SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(ip_checkinterface), 0,
"Verify packet arrives on correct interface");
VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */
static struct netisr_handler ip_nh = {
.nh_name = "ip",
.nh_handler = ip_input,
.nh_proto = NETISR_IP,
#ifdef RSS
.nh_m2cpuid = rss_soft_m2cpuid_v4,
.nh_policy = NETISR_POLICY_CPU,
.nh_dispatch = NETISR_DISPATCH_HYBRID,
#else
.nh_policy = NETISR_POLICY_FLOW,
#endif
};
#ifdef RSS
/*
* Directly dispatched frames are currently assumed
* to have a flowid already calculated.
*
* It should likely have something that assert it
* actually has valid flow details.
*/
static struct netisr_handler ip_direct_nh = {
.nh_name = "ip_direct",
.nh_handler = ip_direct_input,
.nh_proto = NETISR_IP_DIRECT,
.nh_m2cpuid = rss_soft_m2cpuid_v4,
.nh_policy = NETISR_POLICY_CPU,
.nh_dispatch = NETISR_DISPATCH_HYBRID,
};
#endif
extern struct domain inetdomain;
extern struct protosw inetsw[];
u_char ip_protox[IPPROTO_MAX];
VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */
VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */
VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */
#ifdef IPCTL_DEFMTU
SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
&ip_mtu, 0, "Default MTU");
#endif
#ifdef IPSTEALTH
VNET_DEFINE(int, ipstealth);
SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(ipstealth), 0,
"IP stealth mode, no TTL decrementation on forwarding");
#endif
/*
* IP statistics are stored in the "array" of counter(9)s.
*/
VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat);
VNET_PCPUSTAT_SYSINIT(ipstat);
SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat,
"IP statistics (struct ipstat, netinet/ip_var.h)");
#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(ipstat);
#endif /* VIMAGE */
/*
* Kernel module interface for updating ipstat. The argument is an index
* into ipstat treated as an array.
*/
void
kmod_ipstat_inc(int statnum)
{
counter_u64_add(VNET(ipstat)[statnum], 1);
}
void
kmod_ipstat_dec(int statnum)
{
counter_u64_add(VNET(ipstat)[statnum], -1);
}
static int
sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
{
int error, qlimit;
netisr_getqlimit(&ip_nh, &qlimit);
error = sysctl_handle_int(oidp, &qlimit, 0, req);
if (error || !req->newptr)
return (error);
if (qlimit < 1)
return (EINVAL);
return (netisr_setqlimit(&ip_nh, qlimit));
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
"Maximum size of the IP input queue");
static int
sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
{
u_int64_t qdrops_long;
int error, qdrops;
netisr_getqdrops(&ip_nh, &qdrops_long);
qdrops = qdrops_long;
error = sysctl_handle_int(oidp, &qdrops, 0, req);
if (error || !req->newptr)
return (error);
if (qdrops != 0)
return (EINVAL);
netisr_clearqdrops(&ip_nh);
return (0);
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
"Number of packets dropped from the IP input queue");
#ifdef RSS
static int
sysctl_netinet_intr_direct_queue_maxlen(SYSCTL_HANDLER_ARGS)
{
int error, qlimit;
netisr_getqlimit(&ip_direct_nh, &qlimit);
error = sysctl_handle_int(oidp, &qlimit, 0, req);
if (error || !req->newptr)
return (error);
if (qlimit < 1)
return (EINVAL);
return (netisr_setqlimit(&ip_direct_nh, qlimit));
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_direct_queue_maxlen,
CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_direct_queue_maxlen, "I",
"Maximum size of the IP direct input queue");
static int
sysctl_netinet_intr_direct_queue_drops(SYSCTL_HANDLER_ARGS)
{
u_int64_t qdrops_long;
int error, qdrops;
netisr_getqdrops(&ip_direct_nh, &qdrops_long);
qdrops = qdrops_long;
error = sysctl_handle_int(oidp, &qdrops, 0, req);
if (error || !req->newptr)
return (error);
if (qdrops != 0)
return (EINVAL);
netisr_clearqdrops(&ip_direct_nh);
return (0);
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_direct_queue_drops,
CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_direct_queue_drops, "I",
"Number of packets dropped from the IP direct input queue");
#endif /* RSS */
/*
* IP initialization: fill in IP protocol switch table.
* All protocols not implemented in kernel go to raw IP protocol handler.
*/
void
ip_init(void)
{
struct protosw *pr;
int i;
TAILQ_INIT(&V_in_ifaddrhead);
V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
/* Initialize IP reassembly queue. */
ipreass_init();
/* Initialize packet filter hooks. */
V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
V_inet_pfil_hook.ph_af = AF_INET;
if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
printf("%s: WARNING: unable to register pfil hook, "
"error %d\n", __func__, i);
if (hhook_head_register(HHOOK_TYPE_IPSEC_IN, AF_INET,
&V_ipsec_hhh_in[HHOOK_IPSEC_INET],
HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
printf("%s: WARNING: unable to register input helper hook\n",
__func__);
if (hhook_head_register(HHOOK_TYPE_IPSEC_OUT, AF_INET,
&V_ipsec_hhh_out[HHOOK_IPSEC_INET],
HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
printf("%s: WARNING: unable to register output helper hook\n",
__func__);
/* Skip initialization of globals for non-default instances. */
if (!IS_DEFAULT_VNET(curvnet))
return;
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
panic("ip_init: PF_INET not found");
/* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
for (i = 0; i < IPPROTO_MAX; i++)
ip_protox[i] = pr - inetsw;
/*
* Cycle through IP protocols and put them into the appropriate place
* in ip_protox[].
*/
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) {
/* Be careful to only index valid IP protocols. */
if (pr->pr_protocol < IPPROTO_MAX)
ip_protox[pr->pr_protocol] = pr - inetsw;
}
netisr_register(&ip_nh);
#ifdef RSS
netisr_register(&ip_direct_nh);
#endif
}
#ifdef VIMAGE
void
ip_destroy(void)
{
int error;
if ((error = pfil_head_unregister(&V_inet_pfil_hook)) != 0)
printf("%s: WARNING: unable to unregister pfil hook, "
"error %d\n", __func__, error);
error = hhook_head_deregister(V_ipsec_hhh_in[HHOOK_IPSEC_INET]);
if (error != 0) {
printf("%s: WARNING: unable to deregister input helper hook "
"type HHOOK_TYPE_IPSEC_IN, id HHOOK_IPSEC_INET: "
"error %d returned\n", __func__, error);
}
error = hhook_head_deregister(V_ipsec_hhh_out[HHOOK_IPSEC_INET]);
if (error != 0) {
printf("%s: WARNING: unable to deregister output helper hook "
"type HHOOK_TYPE_IPSEC_OUT, id HHOOK_IPSEC_INET: "
"error %d returned\n", __func__, error);
}
/* Cleanup in_ifaddr hash table; should be empty. */
hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
/* Destroy IP reassembly queue. */
ipreass_destroy();
}
#endif
#ifdef RSS
/*
* IP direct input routine.
*
* This is called when reinjecting completed fragments where
* all of the previous checking and book-keeping has been done.
*/
void
ip_direct_input(struct mbuf *m)
{
struct ip *ip;
int hlen;
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
IPSTAT_INC(ips_delivered);
(*inetsw[ip_protox[ip->ip_p]].pr_input)(&m, &hlen, ip->ip_p);
return;
}
#endif
/*
* 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 = NULL;
struct in_ifaddr *ia = NULL;
struct ifaddr *ifa;
struct ifnet *ifp;
int checkif, hlen = 0;
uint16_t sum, ip_len;
int dchg = 0; /* dest changed after fw */
struct in_addr odst; /* original dst address */
M_ASSERTPKTHDR(m);
if (m->m_flags & M_FASTFWD_OURS) {
m->m_flags &= ~M_FASTFWD_OURS;
/* Set up some basics that will be used later. */
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
ip_len = ntohs(ip->ip_len);
goto ours;
}
IPSTAT_INC(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))) == NULL) {
IPSTAT_INC(ips_toosmall);
return;
}
ip = mtod(m, struct ip *);
if (ip->ip_v != IPVERSION) {
IPSTAT_INC(ips_badvers);
goto bad;
}
hlen = ip->ip_hl << 2;
if (hlen < sizeof(struct ip)) { /* minimum header length */
IPSTAT_INC(ips_badhlen);
goto bad;
}
if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == NULL) {
IPSTAT_INC(ips_badhlen);
return;
}
ip = mtod(m, struct ip *);
}
IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL);
/* 127/8 must not appear on wire - RFC1122 */
ifp = m->m_pkthdr.rcvif;
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);
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_INC(ips_badsum);
goto bad;
}
#ifdef ALTQ
if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
/* packet is dropped by traffic conditioner */
return;
#endif
ip_len = ntohs(ip->ip_len);
if (ip_len < hlen) {
IPSTAT_INC(ips_badlen);
goto bad;
}
/*
* 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_len) {
tooshort:
IPSTAT_INC(ips_tooshort);
goto bad;
}
if (m->m_pkthdr.len > ip_len) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip_len;
m->m_pkthdr.len = ip_len;
} else
m_adj(m, ip_len - m->m_pkthdr.len);
}
/* Try to forward the packet, but if we fail continue */
#ifdef IPSEC
/* For now we do not handle IPSEC in tryforward. */
if (!key_havesp(IPSEC_DIR_INBOUND) && !key_havesp(IPSEC_DIR_OUTBOUND) &&
(V_ipforwarding == 1))
if (ip_tryforward(m) == NULL)
return;
/*
* Bypass packet filtering for packets previously handled by IPsec.
*/
if (ip_ipsec_filtertunnel(m))
goto passin;
#else
if (V_ipforwarding == 1)
if (ip_tryforward(m) == NULL)
return;
#endif /* IPSEC */
/*
* Run through list of hooks for input packets.
*
* NB: Beware of the destination address changing (e.g.
* by NAT rewriting). When this happens, tell
* ip_forward to do the right thing.
*/
/* Jump over all PFIL processing if hooks are not active. */
if (!PFIL_HOOKED(&V_inet_pfil_hook))
goto passin;
odst = ip->ip_dst;
if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
return;
if (m == NULL) /* consumed by filter */
return;
ip = mtod(m, struct ip *);
dchg = (odst.s_addr != ip->ip_dst.s_addr);
ifp = m->m_pkthdr.rcvif;
if (m->m_flags & M_FASTFWD_OURS) {
m->m_flags &= ~M_FASTFWD_OURS;
goto ours;
}
if (m->m_flags & M_IP_NEXTHOP) {
if (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
/*
* Directly ship the packet on. This allows
* forwarding packets originally destined to us
* to some other directly connected host.
*/
ip_forward(m, 1);
return;
}
}
passin:
/*
* 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).
*/
if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
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 (V_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(&V_in_ifaddrhead) &&
(m->m_flags & (M_MCAST|M_BCAST)) == 0)
goto ours;
/*
* 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.
*
* XXX - This is the case for carp vhost IPs as well so we
* insert a workaround. If the packet got here, we already
* checked with carp_iamatch() and carp_forus().
*/
checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
ifp->if_carp == NULL && (dchg == 0);
/*
* Check for exact addresses in the hash bucket.
*/
/* IN_IFADDR_RLOCK(); */
LIST_FOREACH(ia, INADDR_HASH(ip->ip_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 == ip->ip_dst.s_addr &&
(!checkif || ia->ia_ifp == ifp)) {
counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
counter_u64_add(ia->ia_ifa.ifa_ibytes,
m->m_pkthdr.len);
/* IN_IFADDR_RUNLOCK(); */
goto ours;
}
}
/* IN_IFADDR_RUNLOCK(); */
/*
* 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 (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
IF_ADDR_RLOCK(ifp);
TAILQ_FOREACH(ifa, &ifp->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 ==
ip->ip_dst.s_addr) {
counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
counter_u64_add(ia->ia_ifa.ifa_ibytes,
m->m_pkthdr.len);
IF_ADDR_RUNLOCK(ifp);
goto ours;
}
#ifdef BOOTP_COMPAT
if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
counter_u64_add(ia->ia_ifa.ifa_ibytes,
m->m_pkthdr.len);
IF_ADDR_RUNLOCK(ifp);
goto ours;
}
#endif
}
IF_ADDR_RUNLOCK(ifp);
ia = NULL;
}
/* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
}
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
if (V_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_mforward(ip, ifp, m, 0) != 0) {
IPSTAT_INC(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_INC(ips_forward);
}
/*
* Assume the packet is for us, to avoid prematurely taking
* a lock on the in_multi hash. Protocols must perform
* their own filtering and update statistics accordingly.
*/
goto ours;
}
if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
goto ours;
if (ip->ip_dst.s_addr == INADDR_ANY)
goto ours;
/*
* Not for us; forward if possible and desirable.
*/
if (V_ipforwarding == 0) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
} else {
ip_forward(m, dchg);
}
return;
ours:
#ifdef IPSTEALTH
/*
* IPSTEALTH: Process non-routing options only
* if the packet is destined for us.
*/
if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1))
return;
#endif /* IPSTEALTH */
/*
* Attempt reassembly; if it succeeds, proceed.
* ip_reass() will return a different mbuf.
*/
if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
/* XXXGL: shouldn't we save & set m_flags? */
m = ip_reass(m);
if (m == NULL)
return;
ip = mtod(m, struct ip *);
/* Get the header length of the reassembled packet */
hlen = ip->ip_hl << 2;
}
#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 (ip_ipsec_input(m, ip->ip_p) != 0)
goto bad;
#endif /* IPSEC */
/*
* Switch out to protocol's input routine.
*/
IPSTAT_INC(ips_delivered);
(*inetsw[ip_protox[ip->ip_p]].pr_input)(&m, &hlen, ip->ip_p);
return;
bad:
m_freem(m);
}
/*
* IP timer processing;
* if a timer expires on a reassembly
* queue, discard it.
*/
void
ip_slowtimo(void)
{
VNET_ITERATOR_DECL(vnet_iter);
VNET_LIST_RLOCK_NOSLEEP();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
ipreass_slowtimo();
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK_NOSLEEP();
}
void
ip_drain(void)
{
VNET_ITERATOR_DECL(vnet_iter);
VNET_LIST_RLOCK_NOSLEEP();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
ipreass_drain();
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK_NOSLEEP();
}
/*
* The protocol to be inserted into ip_protox[] must be already registered
* in inetsw[], either statically or through pf_proto_register().
*/
int
ipproto_register(short ipproto)
{
struct protosw *pr;
/* Sanity checks. */
if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
return (EPROTONOSUPPORT);
/*
* The protocol slot must not be occupied by another protocol
* already. An index pointing to IPPROTO_RAW is unused.
*/
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
return (EPFNOSUPPORT);
if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
return (EEXIST);
/* Find the protocol position in inetsw[] and set the index. */
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) {
ip_protox[pr->pr_protocol] = pr - inetsw;
return (0);
}
}
return (EPROTONOSUPPORT);
}
int
ipproto_unregister(short ipproto)
{
struct protosw *pr;
/* Sanity checks. */
if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
return (EPROTONOSUPPORT);
/* Check if the protocol was indeed registered. */
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
return (EPFNOSUPPORT);
if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
return (ENOENT);
/* Reset the protocol slot to IPPROTO_RAW. */
ip_protox[ipproto] = pr - inetsw;
return (0);
}
u_char inetctlerrmap[PRC_NCMDS] = {
0, 0, 0, 0,
0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
EMSGSIZE, EHOSTUNREACH, 0, 0,
0, 0, EHOSTUNREACH, 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.
*/
void
ip_forward(struct mbuf *m, int srcrt)
{
struct ip *ip = mtod(m, struct ip *);
struct in_ifaddr *ia;
struct mbuf *mcopy;
struct sockaddr_in *sin;
struct in_addr dest;
struct route ro;
int error, type = 0, code = 0, mtu = 0;
if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
}
#ifdef IPSEC
if (ip_ipsec_fwd(m) != 0) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
}
#endif /* IPSEC */
#ifdef IPSTEALTH
if (!V_ipstealth) {
#endif
if (ip->ip_ttl <= IPTTLDEC) {
icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
0, 0);
return;
}
#ifdef IPSTEALTH
}
#endif
bzero(&ro, sizeof(ro));
sin = (struct sockaddr_in *)&ro.ro_dst;
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = ip->ip_dst;
#ifdef RADIX_MPATH
rtalloc_mpath_fib(&ro,
ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
M_GETFIB(m));
#else
in_rtalloc_ign(&ro, 0, M_GETFIB(m));
#endif
if (ro.ro_rt != NULL) {
ia = ifatoia(ro.ro_rt->rt_ifa);
ifa_ref(&ia->ia_ifa);
} else
ia = NULL;
#ifndef IPSEC
/*
* 'ia' may be NULL if there is no route for this destination.
* In case of IPsec, Don't discard it just yet, but pass it to
* ip_output in case of outgoing IPsec policy.
*/
if (!srcrt && ia == NULL) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
RO_RTFREE(&ro);
return;
}
#endif
/*
* 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().
*/
mcopy = m_gethdr(M_NOWAIT, m->m_type);
if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
/*
* It's probably ok if the pkthdr dup fails (because
* the deep copy of the tag chain failed), but for now
* be conservative and just discard the copy since
* code below may some day want the tags.
*/
m_free(mcopy);
mcopy = NULL;
}
if (mcopy != NULL) {
mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
mcopy->m_pkthdr.len = mcopy->m_len;
m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
}
#ifdef IPSTEALTH
if (!V_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.
*/
dest.s_addr = 0;
if (!srcrt && V_ipsendredirects &&
ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
struct rtentry *rt;
rt = ro.ro_rt;
if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
satosin(rt_key(rt))->sin_addr.s_addr != 0) {
#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.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
else
dest.s_addr = ip->ip_dst.s_addr;
/* Router requirements says to only send host redirects */
type = ICMP_REDIRECT;
code = ICMP_REDIRECT_HOST;
}
}
}
error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
if (error == EMSGSIZE && ro.ro_rt)
mtu = ro.ro_rt->rt_mtu;
RO_RTFREE(&ro);
if (error)
IPSTAT_INC(ips_cantforward);
else {
IPSTAT_INC(ips_forward);
if (type)
IPSTAT_INC(ips_redirectsent);
else {
if (mcopy)
m_freem(mcopy);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
}
if (mcopy == NULL) {
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
switch (error) {
case 0: /* forwarded, but need redirect */
/* type, code set above */
break;
case ENETUNREACH:
case EHOSTUNREACH:
case ENETDOWN:
case EHOSTDOWN:
default:
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
break;
case EMSGSIZE:
type = ICMP_UNREACH;
code = ICMP_UNREACH_NEEDFRAG;
#ifdef IPSEC
/*
* If IPsec is configured for this path,
* override any possibly mtu value set by ip_output.
*/
mtu = ip_ipsec_mtu(mcopy, mtu);
#endif /* IPSEC */
/*
* If the MTU was set before make sure we are below the
* interface MTU.
* If the MTU wasn't set before use the interface mtu or
* fall back to the next smaller mtu step compared to the
* current packet size.
*/
if (mtu != 0) {
if (ia != NULL)
mtu = min(mtu, ia->ia_ifp->if_mtu);
} else {
if (ia != NULL)
mtu = ia->ia_ifp->if_mtu;
else
mtu = ip_next_mtu(ntohs(ip->ip_len), 0);
}
IPSTAT_INC(ips_cantfrag);
break;
case ENOBUFS:
case EACCES: /* ipfw denied packet */
m_freem(mcopy);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
if (ia != NULL)
ifa_free(&ia->ia_ifa);
icmp_error(mcopy, type, code, dest.s_addr, mtu);
}
void
ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
struct mbuf *m)
{
if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
struct bintime bt;
bintime(&bt);
if (inp->inp_socket->so_options & SO_BINTIME) {
*mp = sbcreatecontrol((caddr_t)&bt, sizeof(bt),
SCM_BINTIME, SOL_SOCKET);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_socket->so_options & SO_TIMESTAMP) {
struct timeval tv;
bintime2timeval(&bt, &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;
}
if (inp->inp_flags & INP_RECVTTL) {
*mp = sbcreatecontrol((caddr_t)&ip->ip_ttl,
sizeof(u_char), IP_RECVTTL, 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(m),
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 <= V_if_index) {
sdp = (struct sockaddr_dl *)ifp->if_addr->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;
}
if (inp->inp_flags & INP_RECVTOS) {
*mp = sbcreatecontrol((caddr_t)&ip->ip_tos,
sizeof(u_char), IP_RECVTOS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_flags2 & INP_RECVFLOWID) {
uint32_t flowid, flow_type;
flowid = m->m_pkthdr.flowid;
flow_type = M_HASHTYPE_GET(m);
/*
* XXX should handle the failure of one or the
* other - don't populate both?
*/
*mp = sbcreatecontrol((caddr_t) &flowid,
sizeof(uint32_t), IP_FLOWID, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
*mp = sbcreatecontrol((caddr_t) &flow_type,
sizeof(uint32_t), IP_FLOWTYPE, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#ifdef RSS
if (inp->inp_flags2 & INP_RECVRSSBUCKETID) {
uint32_t flowid, flow_type;
uint32_t rss_bucketid;
flowid = m->m_pkthdr.flowid;
flow_type = M_HASHTYPE_GET(m);
if (rss_hash2bucket(flowid, flow_type, &rss_bucketid) == 0) {
*mp = sbcreatecontrol((caddr_t) &rss_bucketid,
sizeof(uint32_t), IP_RSSBUCKETID, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
}
#endif
}
/*
* XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
* ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
* locking. This code remains in ip_input.c as ip_mroute.c is optionally
* compiled.
*/
static VNET_DEFINE(int, ip_rsvp_on);
VNET_DEFINE(struct socket *, ip_rsvpd);
#define V_ip_rsvp_on VNET(ip_rsvp_on)
int
ip_rsvp_init(struct socket *so)
{
if (so->so_type != SOCK_RAW ||
so->so_proto->pr_protocol != IPPROTO_RSVP)
return EOPNOTSUPP;
if (V_ip_rsvpd != NULL)
return EADDRINUSE;
V_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 (!V_ip_rsvp_on) {
V_ip_rsvp_on = 1;
V_rsvp_on++;
}
return 0;
}
int
ip_rsvp_done(void)
{
V_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 (V_ip_rsvp_on) {
V_ip_rsvp_on = 0;
V_rsvp_on--;
}
return 0;
}
int
rsvp_input(struct mbuf **mp, int *offp, int proto)
{
struct mbuf *m;
m = *mp;
*mp = NULL;
if (rsvp_input_p) { /* call the real one if loaded */
*mp = m;
rsvp_input_p(mp, offp, proto);
return (IPPROTO_DONE);
}
/* Can still get packets with rsvp_on = 0 if there is a local member
* of the group to which the RSVP packet is addressed. But in this
* case we want to throw the packet away.
*/
if (!V_rsvp_on) {
m_freem(m);
return (IPPROTO_DONE);
}
if (V_ip_rsvpd != NULL) {
*mp = m;
rip_input(mp, offp, proto);
return (IPPROTO_DONE);
}
/* Drop the packet */
m_freem(m);
return (IPPROTO_DONE);
}