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freebsd-src/sys/netpfil/ipfilter/netinet/ip_fil_freebsd.c
Kristof Provost ffeab76b68 pfil: PFIL_PASS never frees the mbuf 
pfil hooks (i.e. firewalls) may pass, modify or free the mbuf passed
to them. (E.g. when rejecting a packet, or when gathering up packets
for reassembly).

If the hook returns PFIL_PASS the mbuf must still be present. Assert
this in pfil_mem_common() and ensure that ipfilter follows this
convention. pf and ipfw already did.
Similarly, if the hook returns PFIL_DROPPED or PFIL_CONSUMED the mbuf
must have been freed (or now be owned by the firewall for further
processing, like packet scheduling or reassembly).

This allows us to remove a few extraneous NULL checks.

Suggested by:	tuexen
Reviewed by:	tuexen, zlei
Sponsored by:	Rubicon Communications, LLC ("Netgate")
Differential Revision:	https://reviews.freebsd.org/D43617
2024-01-29 14:10:19 +01:00

1463 lines
31 KiB
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/*
* Copyright (C) 2012 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*/
#if defined(KERNEL) || defined(_KERNEL)
# undef KERNEL
# undef _KERNEL
# define KERNEL 1
# define _KERNEL 1
#endif
#if defined(__FreeBSD__) && \
!defined(KLD_MODULE) && !defined(IPFILTER_LKM)
# include "opt_inet6.h"
#endif
#include <sys/param.h>
#include <sys/eventhandler.h>
#include <sys/conf.h>
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/time.h>
#include <sys/systm.h>
#include <sys/dirent.h>
#if defined(__FreeBSD__)
# include <sys/jail.h>
#endif
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/sockopt.h>
#include <sys/socket.h>
#include <sys/selinfo.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <netinet/in.h>
#include <netinet/in_fib.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <net/vnet.h>
#include <netinet/udp.h>
#include <netinet/tcpip.h>
#include <netinet/ip_icmp.h>
#include "netinet/ip_compat.h"
#ifdef USE_INET6
# include <netinet/icmp6.h>
#endif
#include "netinet/ip_fil.h"
#include "netinet/ip_nat.h"
#include "netinet/ip_frag.h"
#include "netinet/ip_state.h"
#include "netinet/ip_proxy.h"
#include "netinet/ip_auth.h"
#include "netinet/ip_sync.h"
#include "netinet/ip_lookup.h"
#include "netinet/ip_dstlist.h"
#ifdef IPFILTER_SCAN
# include "netinet/ip_scan.h"
#endif
#include "netinet/ip_pool.h"
#include <sys/malloc.h>
#include <sys/kernel.h>
#ifdef CSUM_DATA_VALID
# include <machine/in_cksum.h>
#endif
extern int ip_optcopy(struct ip *, struct ip *);
#ifdef IPFILTER_M_IPFILTER
MALLOC_DEFINE(M_IPFILTER, "ipfilter", "IP Filter packet filter data structures");
#endif
static int ipf_send_ip(fr_info_t *, mb_t *);
static void ipf_timer_func(void *arg);
VNET_DEFINE(ipf_main_softc_t, ipfmain) = {
.ipf_running = -2,
};
#define V_ipfmain VNET(ipfmain)
#include <sys/conf.h>
#include <net/pfil.h>
VNET_DEFINE_STATIC(eventhandler_tag, ipf_arrivetag);
VNET_DEFINE_STATIC(eventhandler_tag, ipf_departtag);
#define V_ipf_arrivetag VNET(ipf_arrivetag)
#define V_ipf_departtag VNET(ipf_departtag)
#if 0
/*
* Disable the "cloner" event handler; we are getting interface
* events before the firewall is fully initiallized and also no vnet
* information thus leading to uninitialised memory accesses.
* In addition it is unclear why we need it in first place.
* If it turns out to be needed, well need a dedicated event handler
* for it to deal with the ifc and the correct vnet.
*/
VNET_DEFINE_STATIC(eventhandler_tag, ipf_clonetag);
#define V_ipf_clonetag VNET(ipf_clonetag)
#endif
static void ipf_ifevent(void *arg, struct ifnet *ifp);
static void ipf_ifevent(void *arg, struct ifnet *ifp)
{
CURVNET_SET(ifp->if_vnet);
if (V_ipfmain.ipf_running > 0)
ipf_sync(&V_ipfmain, NULL);
CURVNET_RESTORE();
}
static pfil_return_t
ipf_check_wrapper(struct mbuf **mp, struct ifnet *ifp, int flags,
void *ruleset __unused, struct inpcb *inp)
{
struct ip *ip = mtod(*mp, struct ip *);
pfil_return_t rv;
CURVNET_SET(ifp->if_vnet);
rv = ipf_check(&V_ipfmain, ip, ip->ip_hl << 2, ifp,
!!(flags & PFIL_OUT), mp);
CURVNET_RESTORE();
if (rv == 0 && *mp == NULL)
return (PFIL_CONSUMED);
return (rv == 0 ? PFIL_PASS : PFIL_DROPPED);
}
#ifdef USE_INET6
static pfil_return_t
ipf_check_wrapper6(struct mbuf **mp, struct ifnet *ifp, int flags,
void *ruleset __unused, struct inpcb *inp)
{
pfil_return_t rv;
CURVNET_SET(ifp->if_vnet);
rv = ipf_check(&V_ipfmain, mtod(*mp, struct ip *),
sizeof(struct ip6_hdr), ifp, !!(flags & PFIL_OUT), mp);
CURVNET_RESTORE();
if (rv == 0 && *mp == NULL)
return (PFIL_CONSUMED);
return (rv == 0 ? PFIL_PASS : PFIL_DROPPED);
}
# endif
#if defined(IPFILTER_LKM)
int ipf_identify(char *s)
{
if (strcmp(s, "ipl") == 0)
return (1);
return (0);
}
#endif /* IPFILTER_LKM */
static void
ipf_timer_func(void *arg)
{
ipf_main_softc_t *softc = arg;
SPL_INT(s);
SPL_NET(s);
READ_ENTER(&softc->ipf_global);
if (softc->ipf_running > 0)
ipf_slowtimer(softc);
if (softc->ipf_running == -1 || softc->ipf_running == 1) {
#if 0
softc->ipf_slow_ch = timeout(ipf_timer_func, softc, hz/2);
#endif
callout_init(&softc->ipf_slow_ch, 1);
callout_reset(&softc->ipf_slow_ch,
(hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
ipf_timer_func, softc);
}
RWLOCK_EXIT(&softc->ipf_global);
SPL_X(s);
}
int
ipfattach(ipf_main_softc_t *softc)
{
#ifdef USE_SPL
int s;
#endif
SPL_NET(s);
if (softc->ipf_running > 0) {
SPL_X(s);
return (EBUSY);
}
if (ipf_init_all(softc) < 0) {
SPL_X(s);
return (EIO);
}
bzero((char *)V_ipfmain.ipf_selwait, sizeof(V_ipfmain.ipf_selwait));
softc->ipf_running = 1;
if (softc->ipf_control_forwarding & 1)
V_ipforwarding = 1;
SPL_X(s);
#if 0
softc->ipf_slow_ch = timeout(ipf_timer_func, softc,
(hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT);
#endif
callout_init(&softc->ipf_slow_ch, 1);
callout_reset(&softc->ipf_slow_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
ipf_timer_func, softc);
return (0);
}
/*
* Disable the filter by removing the hooks from the IP input/output
* stream.
*/
int
ipfdetach(ipf_main_softc_t *softc)
{
#ifdef USE_SPL
int s;
#endif
if (softc->ipf_control_forwarding & 2)
V_ipforwarding = 0;
SPL_NET(s);
#if 0
if (softc->ipf_slow_ch.callout != NULL)
untimeout(ipf_timer_func, softc, softc->ipf_slow_ch);
bzero(&softc->ipf_slow, sizeof(softc->ipf_slow));
#endif
callout_drain(&softc->ipf_slow_ch);
ipf_fini_all(softc);
softc->ipf_running = -2;
SPL_X(s);
return (0);
}
/*
* Filter ioctl interface.
*/
int
ipfioctl(struct cdev *dev, ioctlcmd_t cmd, caddr_t data,
int mode, struct thread *p)
#define p_cred td_ucred
#define p_uid td_ucred->cr_ruid
{
int error = 0, unit = 0;
SPL_INT(s);
CURVNET_SET(TD_TO_VNET(p));
if (securelevel_ge(p->p_cred, 3) && (mode & FWRITE))
{
V_ipfmain.ipf_interror = 130001;
CURVNET_RESTORE();
return (EPERM);
}
if (jailed_without_vnet(p->p_cred)) {
V_ipfmain.ipf_interror = 130018;
CURVNET_RESTORE();
return (EOPNOTSUPP);
}
unit = GET_MINOR(dev);
if ((IPL_LOGMAX < unit) || (unit < 0)) {
V_ipfmain.ipf_interror = 130002;
CURVNET_RESTORE();
return (ENXIO);
}
if (V_ipfmain.ipf_running <= 0) {
if (unit != IPL_LOGIPF && cmd != SIOCIPFINTERROR) {
V_ipfmain.ipf_interror = 130003;
CURVNET_RESTORE();
return (EIO);
}
if (cmd != SIOCIPFGETNEXT && cmd != SIOCIPFGET &&
cmd != SIOCIPFSET && cmd != SIOCFRENB &&
cmd != SIOCGETFS && cmd != SIOCGETFF &&
cmd != SIOCIPFINTERROR) {
V_ipfmain.ipf_interror = 130004;
CURVNET_RESTORE();
return (EIO);
}
}
SPL_NET(s);
error = ipf_ioctlswitch(&V_ipfmain, unit, data, cmd, mode, p->p_uid, p);
CURVNET_RESTORE();
if (error != -1) {
SPL_X(s);
return (error);
}
SPL_X(s);
return (error);
}
/*
* ipf_send_reset - this could conceivably be a call to tcp_respond(), but that
* requires a large amount of setting up and isn't any more efficient.
*/
int
ipf_send_reset(fr_info_t *fin)
{
struct tcphdr *tcp, *tcp2;
int tlen = 0, hlen;
struct mbuf *m;
#ifdef USE_INET6
ip6_t *ip6;
#endif
ip_t *ip;
tcp = fin->fin_dp;
if (tcp->th_flags & TH_RST)
return (-1); /* feedback loop */
if (ipf_checkl4sum(fin) == -1)
return (-1);
tlen = fin->fin_dlen - (TCP_OFF(tcp) << 2) +
((tcp->th_flags & TH_SYN) ? 1 : 0) +
((tcp->th_flags & TH_FIN) ? 1 : 0);
#ifdef USE_INET6
hlen = (fin->fin_v == 6) ? sizeof(ip6_t) : sizeof(ip_t);
#else
hlen = sizeof(ip_t);
#endif
#ifdef MGETHDR
MGETHDR(m, M_NOWAIT, MT_HEADER);
#else
MGET(m, M_NOWAIT, MT_HEADER);
#endif
if (m == NULL)
return (-1);
if (sizeof(*tcp2) + hlen > MLEN) {
if (!(MCLGET(m, M_NOWAIT))) {
FREE_MB_T(m);
return (-1);
}
}
m->m_len = sizeof(*tcp2) + hlen;
m->m_data += max_linkhdr;
m->m_pkthdr.len = m->m_len;
m->m_pkthdr.rcvif = (struct ifnet *)0;
ip = mtod(m, struct ip *);
bzero((char *)ip, hlen);
#ifdef USE_INET6
ip6 = (ip6_t *)ip;
#endif
tcp2 = (struct tcphdr *)((char *)ip + hlen);
tcp2->th_sport = tcp->th_dport;
tcp2->th_dport = tcp->th_sport;
if (tcp_get_flags(tcp) & TH_ACK) {
tcp2->th_seq = tcp->th_ack;
tcp_set_flags(tcp2, TH_RST);
tcp2->th_ack = 0;
} else {
tcp2->th_seq = 0;
tcp2->th_ack = ntohl(tcp->th_seq);
tcp2->th_ack += tlen;
tcp2->th_ack = htonl(tcp2->th_ack);
tcp_set_flags(tcp2, TH_RST|TH_ACK);
}
TCP_OFF_A(tcp2, sizeof(*tcp2) >> 2);
tcp2->th_win = tcp->th_win;
tcp2->th_sum = 0;
tcp2->th_urp = 0;
#ifdef USE_INET6
if (fin->fin_v == 6) {
ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
ip6->ip6_plen = htons(sizeof(struct tcphdr));
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_hlim = 0;
ip6->ip6_src = fin->fin_dst6.in6;
ip6->ip6_dst = fin->fin_src6.in6;
tcp2->th_sum = in6_cksum(m, IPPROTO_TCP,
sizeof(*ip6), sizeof(*tcp2));
return (ipf_send_ip(fin, m));
}
#endif
ip->ip_p = IPPROTO_TCP;
ip->ip_len = htons(sizeof(struct tcphdr));
ip->ip_src.s_addr = fin->fin_daddr;
ip->ip_dst.s_addr = fin->fin_saddr;
tcp2->th_sum = in_cksum(m, hlen + sizeof(*tcp2));
ip->ip_len = htons(hlen + sizeof(*tcp2));
return (ipf_send_ip(fin, m));
}
/*
* ip_len must be in network byte order when called.
*/
static int
ipf_send_ip(fr_info_t *fin, mb_t *m)
{
fr_info_t fnew;
ip_t *ip, *oip;
int hlen;
ip = mtod(m, ip_t *);
bzero((char *)&fnew, sizeof(fnew));
fnew.fin_main_soft = fin->fin_main_soft;
IP_V_A(ip, fin->fin_v);
switch (fin->fin_v)
{
case 4 :
oip = fin->fin_ip;
hlen = sizeof(*oip);
fnew.fin_v = 4;
fnew.fin_p = ip->ip_p;
fnew.fin_plen = ntohs(ip->ip_len);
IP_HL_A(ip, sizeof(*oip) >> 2);
ip->ip_tos = oip->ip_tos;
ip->ip_id = fin->fin_ip->ip_id;
ip->ip_off = htons(V_path_mtu_discovery ? IP_DF : 0);
ip->ip_ttl = V_ip_defttl;
ip->ip_sum = 0;
break;
#ifdef USE_INET6
case 6 :
{
ip6_t *ip6 = (ip6_t *)ip;
ip6->ip6_vfc = 0x60;
ip6->ip6_hlim = IPDEFTTL;
hlen = sizeof(*ip6);
fnew.fin_p = ip6->ip6_nxt;
fnew.fin_v = 6;
fnew.fin_plen = ntohs(ip6->ip6_plen) + hlen;
break;
}
#endif
default :
return (EINVAL);
}
#ifdef IPSEC_SUPPORT
m->m_pkthdr.rcvif = NULL;
#endif
fnew.fin_ifp = fin->fin_ifp;
fnew.fin_flx = FI_NOCKSUM;
fnew.fin_m = m;
fnew.fin_ip = ip;
fnew.fin_mp = &m;
fnew.fin_hlen = hlen;
fnew.fin_dp = (char *)ip + hlen;
(void) ipf_makefrip(hlen, ip, &fnew);
return (ipf_fastroute(m, &m, &fnew, NULL));
}
int
ipf_send_icmp_err(int type, fr_info_t *fin, int dst)
{
int err, hlen, xtra, iclen, ohlen, avail, code;
struct in_addr dst4;
struct icmp *icmp;
struct mbuf *m;
i6addr_t dst6;
void *ifp;
#ifdef USE_INET6
ip6_t *ip6;
#endif
ip_t *ip, *ip2;
if ((type < 0) || (type >= ICMP_MAXTYPE))
return (-1);
code = fin->fin_icode;
#ifdef USE_INET6
/* See NetBSD ip_fil_netbsd.c r1.4: */
if ((code < 0) || (code >= sizeof(icmptoicmp6unreach)/sizeof(int)))
return (-1);
#endif
if (ipf_checkl4sum(fin) == -1)
return (-1);
#ifdef MGETHDR
MGETHDR(m, M_NOWAIT, MT_HEADER);
#else
MGET(m, M_NOWAIT, MT_HEADER);
#endif
if (m == NULL)
return (-1);
avail = MHLEN;
xtra = 0;
hlen = 0;
ohlen = 0;
dst4.s_addr = 0;
ifp = fin->fin_ifp;
if (fin->fin_v == 4) {
if ((fin->fin_p == IPPROTO_ICMP) && !(fin->fin_flx & FI_SHORT))
switch (ntohs(fin->fin_data[0]) >> 8)
{
case ICMP_ECHO :
case ICMP_TSTAMP :
case ICMP_IREQ :
case ICMP_MASKREQ :
break;
default :
FREE_MB_T(m);
return (0);
}
if (dst == 0) {
if (ipf_ifpaddr(&V_ipfmain, 4, FRI_NORMAL, ifp,
&dst6, NULL) == -1) {
FREE_MB_T(m);
return (-1);
}
dst4 = dst6.in4;
} else
dst4.s_addr = fin->fin_daddr;
hlen = sizeof(ip_t);
ohlen = fin->fin_hlen;
iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
if (fin->fin_hlen < fin->fin_plen)
xtra = MIN(fin->fin_dlen, 8);
else
xtra = 0;
}
#ifdef USE_INET6
else if (fin->fin_v == 6) {
hlen = sizeof(ip6_t);
ohlen = sizeof(ip6_t);
iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
type = icmptoicmp6types[type];
if (type == ICMP6_DST_UNREACH)
code = icmptoicmp6unreach[code];
if (iclen + max_linkhdr + fin->fin_plen > avail) {
if (!(MCLGET(m, M_NOWAIT))) {
FREE_MB_T(m);
return (-1);
}
avail = MCLBYTES;
}
xtra = MIN(fin->fin_plen, avail - iclen - max_linkhdr);
xtra = MIN(xtra, IPV6_MMTU - iclen);
if (dst == 0) {
if (ipf_ifpaddr(&V_ipfmain, 6, FRI_NORMAL, ifp,
&dst6, NULL) == -1) {
FREE_MB_T(m);
return (-1);
}
} else
dst6 = fin->fin_dst6;
}
#endif
else {
FREE_MB_T(m);
return (-1);
}
avail -= (max_linkhdr + iclen);
if (avail < 0) {
FREE_MB_T(m);
return (-1);
}
if (xtra > avail)
xtra = avail;
iclen += xtra;
m->m_data += max_linkhdr;
m->m_pkthdr.rcvif = (struct ifnet *)0;
m->m_pkthdr.len = iclen;
m->m_len = iclen;
ip = mtod(m, ip_t *);
icmp = (struct icmp *)((char *)ip + hlen);
ip2 = (ip_t *)&icmp->icmp_ip;
icmp->icmp_type = type;
icmp->icmp_code = fin->fin_icode;
icmp->icmp_cksum = 0;
#ifdef icmp_nextmtu
if (type == ICMP_UNREACH && fin->fin_icode == ICMP_UNREACH_NEEDFRAG) {
if (fin->fin_mtu != 0) {
icmp->icmp_nextmtu = htons(fin->fin_mtu);
} else if (ifp != NULL) {
icmp->icmp_nextmtu = htons(GETIFMTU_4(ifp));
} else { /* make up a number... */
icmp->icmp_nextmtu = htons(fin->fin_plen - 20);
}
}
#endif
bcopy((char *)fin->fin_ip, (char *)ip2, ohlen);
#ifdef USE_INET6
ip6 = (ip6_t *)ip;
if (fin->fin_v == 6) {
ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
ip6->ip6_plen = htons(iclen - hlen);
ip6->ip6_nxt = IPPROTO_ICMPV6;
ip6->ip6_hlim = 0;
ip6->ip6_src = dst6.in6;
ip6->ip6_dst = fin->fin_src6.in6;
if (xtra > 0)
bcopy((char *)fin->fin_ip + ohlen,
(char *)&icmp->icmp_ip + ohlen, xtra);
icmp->icmp_cksum = in6_cksum(m, IPPROTO_ICMPV6,
sizeof(*ip6), iclen - hlen);
} else
#endif
{
ip->ip_p = IPPROTO_ICMP;
ip->ip_src.s_addr = dst4.s_addr;
ip->ip_dst.s_addr = fin->fin_saddr;
if (xtra > 0)
bcopy((char *)fin->fin_ip + ohlen,
(char *)&icmp->icmp_ip + ohlen, xtra);
icmp->icmp_cksum = ipf_cksum((u_short *)icmp,
sizeof(*icmp) + 8);
ip->ip_len = htons(iclen);
ip->ip_p = IPPROTO_ICMP;
}
err = ipf_send_ip(fin, m);
return (err);
}
/*
* m0 - pointer to mbuf where the IP packet starts
* mpp - pointer to the mbuf pointer that is the start of the mbuf chain
*/
int
ipf_fastroute(mb_t *m0, mb_t **mpp, fr_info_t *fin, frdest_t *fdp)
{
register struct ip *ip, *mhip;
register struct mbuf *m = *mpp;
int len, off, error = 0, hlen, code;
struct ifnet *ifp, *sifp;
struct route ro;
struct sockaddr_in *dst;
const struct sockaddr *gw;
struct nhop_object *nh;
u_long fibnum = 0;
u_short ip_off;
frdest_t node;
frentry_t *fr;
#ifdef M_WRITABLE
/*
* HOT FIX/KLUDGE:
*
* If the mbuf we're about to send is not writable (because of
* a cluster reference, for example) we'll need to make a copy
* of it since this routine modifies the contents.
*
* If you have non-crappy network hardware that can transmit data
* from the mbuf, rather than making a copy, this is gonna be a
* problem.
*/
if (M_WRITABLE(m) == 0) {
m0 = m_dup(m, M_NOWAIT);
if (m0 != NULL) {
FREE_MB_T(m);
m = m0;
*mpp = m;
} else {
error = ENOBUFS;
FREE_MB_T(m);
goto done;
}
}
#endif
#ifdef USE_INET6
if (fin->fin_v == 6) {
/*
* currently "to <if>" and "to <if>:ip#" are not supported
* for IPv6
*/
return (ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL));
}
#endif
hlen = fin->fin_hlen;
ip = mtod(m0, struct ip *);
ifp = NULL;
/*
* Route packet.
*/
bzero(&ro, sizeof (ro));
dst = (struct sockaddr_in *)&ro.ro_dst;
dst->sin_family = AF_INET;
dst->sin_addr = ip->ip_dst;
dst->sin_len = sizeof(dst);
gw = (const struct sockaddr *)dst;
fr = fin->fin_fr;
if ((fr != NULL) && !(fr->fr_flags & FR_KEEPSTATE) && (fdp != NULL) &&
(fdp->fd_type == FRD_DSTLIST)) {
if (ipf_dstlist_select_node(fin, fdp->fd_ptr, NULL, &node) == 0)
fdp = &node;
}
if (fdp != NULL)
ifp = fdp->fd_ptr;
else
ifp = fin->fin_ifp;
if ((ifp == NULL) && ((fr == NULL) || !(fr->fr_flags & FR_FASTROUTE))) {
error = -2;
goto bad;
}
if ((fdp != NULL) && (fdp->fd_ip.s_addr != 0))
dst->sin_addr = fdp->fd_ip;
fibnum = M_GETFIB(m0);
NET_EPOCH_ASSERT();
nh = fib4_lookup(fibnum, dst->sin_addr, 0, NHR_NONE, 0);
if (nh == NULL) {
if (in_localaddr(ip->ip_dst))
error = EHOSTUNREACH;
else
error = ENETUNREACH;
goto bad;
}
if (ifp == NULL)
ifp = nh->nh_ifp;
if (nh->nh_flags & NHF_GATEWAY) {
gw = &nh->gw_sa;
ro.ro_flags |= RT_HAS_GW;
}
/*
* For input packets which are being "fastrouted", they won't
* go back through output filtering and miss their chance to get
* NAT'd and counted. Duplicated packets aren't considered to be
* part of the normal packet stream, so do not NAT them or pass
* them through stateful checking, etc.
*/
if ((fdp != &fr->fr_dif) && (fin->fin_out == 0)) {
sifp = fin->fin_ifp;
fin->fin_ifp = ifp;
fin->fin_out = 1;
(void) ipf_acctpkt(fin, NULL);
fin->fin_fr = NULL;
if (!fr || !(fr->fr_flags & FR_RETMASK)) {
u_32_t pass;
(void) ipf_state_check(fin, &pass);
}
switch (ipf_nat_checkout(fin, NULL))
{
case 0 :
break;
case 1 :
ip->ip_sum = 0;
break;
case -1 :
error = -1;
goto bad;
break;
}
fin->fin_ifp = sifp;
fin->fin_out = 0;
} else
ip->ip_sum = 0;
/*
* If small enough for interface, can just send directly.
*/
if (ntohs(ip->ip_len) <= ifp->if_mtu) {
if (!ip->ip_sum)
ip->ip_sum = in_cksum(m, hlen);
error = (*ifp->if_output)(ifp, m, gw, &ro);
goto done;
}
/*
* Too large for interface; fragment if possible.
* Must be able to put at least 8 bytes per fragment.
*/
ip_off = ntohs(ip->ip_off);
if (ip_off & IP_DF) {
error = EMSGSIZE;
goto bad;
}
len = (ifp->if_mtu - hlen) &~ 7;
if (len < 8) {
error = EMSGSIZE;
goto bad;
}
{
int mhlen, firstlen = len;
struct mbuf **mnext = &m->m_act;
/*
* Loop through length of segment after first fragment,
* make new header and copy data of each part and link onto chain.
*/
m0 = m;
mhlen = sizeof (struct ip);
for (off = hlen + len; off < ntohs(ip->ip_len); off += len) {
#ifdef MGETHDR
MGETHDR(m, M_NOWAIT, MT_HEADER);
#else
MGET(m, M_NOWAIT, MT_HEADER);
#endif
if (m == NULL) {
m = m0;
error = ENOBUFS;
goto bad;
}
m->m_data += max_linkhdr;
mhip = mtod(m, struct ip *);
bcopy((char *)ip, (char *)mhip, sizeof(*ip));
if (hlen > sizeof (struct ip)) {
mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
IP_HL_A(mhip, mhlen >> 2);
}
m->m_len = mhlen;
mhip->ip_off = ((off - hlen) >> 3) + ip_off;
if (off + len >= ntohs(ip->ip_len))
len = ntohs(ip->ip_len) - off;
else
mhip->ip_off |= IP_MF;
mhip->ip_len = htons((u_short)(len + mhlen));
*mnext = m;
m->m_next = m_copym(m0, off, len, M_NOWAIT);
if (m->m_next == 0) {
error = ENOBUFS; /* ??? */
goto sendorfree;
}
m->m_pkthdr.len = mhlen + len;
m->m_pkthdr.rcvif = NULL;
mhip->ip_off = htons((u_short)mhip->ip_off);
mhip->ip_sum = 0;
mhip->ip_sum = in_cksum(m, mhlen);
mnext = &m->m_act;
}
/*
* Update first fragment by trimming what's been copied out
* and updating header, then send each fragment (in order).
*/
m_adj(m0, hlen + firstlen - ip->ip_len);
ip->ip_len = htons((u_short)(hlen + firstlen));
ip->ip_off = htons((u_short)IP_MF);
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m0, hlen);
sendorfree:
for (m = m0; m; m = m0) {
m0 = m->m_act;
m->m_act = 0;
if (error == 0)
error = (*ifp->if_output)(ifp, m, gw, &ro);
else
FREE_MB_T(m);
}
}
done:
if (!error)
V_ipfmain.ipf_frouteok[0]++;
else
V_ipfmain.ipf_frouteok[1]++;
return (0);
bad:
if (error == EMSGSIZE) {
sifp = fin->fin_ifp;
code = fin->fin_icode;
fin->fin_icode = ICMP_UNREACH_NEEDFRAG;
fin->fin_ifp = ifp;
(void) ipf_send_icmp_err(ICMP_UNREACH, fin, 1);
fin->fin_ifp = sifp;
fin->fin_icode = code;
}
FREE_MB_T(m);
goto done;
}
int
ipf_verifysrc(fr_info_t *fin)
{
struct nhop_object *nh;
NET_EPOCH_ASSERT();
nh = fib4_lookup(RT_DEFAULT_FIB, fin->fin_src, 0, NHR_NONE, 0);
if (nh == NULL)
return (0);
return (fin->fin_ifp == nh->nh_ifp);
}
/*
* return the first IP Address associated with an interface
*/
int
ipf_ifpaddr(ipf_main_softc_t *softc, int v, int atype, void *ifptr,
i6addr_t *inp, i6addr_t *inpmask)
{
#ifdef USE_INET6
struct in6_addr *ia6 = NULL;
#endif
struct sockaddr *sock, *mask;
struct sockaddr_in *sin;
struct ifaddr *ifa;
struct ifnet *ifp;
if ((ifptr == NULL) || (ifptr == (void *)-1))
return (-1);
sin = NULL;
ifp = ifptr;
if (v == 4)
inp->in4.s_addr = 0;
#ifdef USE_INET6
else if (v == 6)
bzero((char *)inp, sizeof(*inp));
#endif
ifa = CK_STAILQ_FIRST(&ifp->if_addrhead);
sock = ifa->ifa_addr;
while (sock != NULL && ifa != NULL) {
sin = (struct sockaddr_in *)sock;
if ((v == 4) && (sin->sin_family == AF_INET))
break;
#ifdef USE_INET6
if ((v == 6) && (sin->sin_family == AF_INET6)) {
ia6 = &((struct sockaddr_in6 *)sin)->sin6_addr;
if (!IN6_IS_ADDR_LINKLOCAL(ia6) &&
!IN6_IS_ADDR_LOOPBACK(ia6))
break;
}
#endif
ifa = CK_STAILQ_NEXT(ifa, ifa_link);
if (ifa != NULL)
sock = ifa->ifa_addr;
}
if (ifa == NULL || sin == NULL)
return (-1);
mask = ifa->ifa_netmask;
if (atype == FRI_BROADCAST)
sock = ifa->ifa_broadaddr;
else if (atype == FRI_PEERADDR)
sock = ifa->ifa_dstaddr;
if (sock == NULL)
return (-1);
#ifdef USE_INET6
if (v == 6) {
return (ipf_ifpfillv6addr(atype, (struct sockaddr_in6 *)sock,
(struct sockaddr_in6 *)mask,
inp, inpmask));
}
#endif
return (ipf_ifpfillv4addr(atype, (struct sockaddr_in *)sock,
(struct sockaddr_in *)mask,
&inp->in4, &inpmask->in4));
}
u_32_t
ipf_newisn(fr_info_t *fin)
{
u_32_t newiss;
newiss = arc4random();
return (newiss);
}
int
ipf_checkv4sum(fr_info_t *fin)
{
#ifdef CSUM_DATA_VALID
int manual = 0;
u_short sum;
ip_t *ip;
mb_t *m;
if ((fin->fin_flx & FI_NOCKSUM) != 0)
return (0);
if ((fin->fin_flx & FI_SHORT) != 0)
return (1);
if (fin->fin_cksum != FI_CK_NEEDED)
return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
m = fin->fin_m;
if (m == NULL) {
manual = 1;
goto skipauto;
}
ip = fin->fin_ip;
if ((m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID)) ==
CSUM_IP_CHECKED) {
fin->fin_cksum = FI_CK_BAD;
fin->fin_flx |= FI_BAD;
DT2(ipf_fi_bad_checkv4sum_csum_ip_checked, fr_info_t *, fin, u_int, m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID));
return (-1);
}
if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
/* Depending on the driver, UDP may have zero checksum */
if (fin->fin_p == IPPROTO_UDP && (fin->fin_flx &
(FI_FRAG|FI_SHORT|FI_BAD)) == 0) {
udphdr_t *udp = fin->fin_dp;
if (udp->uh_sum == 0) {
/*
* we're good no matter what the hardware
* checksum flags and csum_data say (handling
* of csum_data for zero UDP checksum is not
* consistent across all drivers)
*/
fin->fin_cksum = 1;
return (0);
}
}
if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
sum = m->m_pkthdr.csum_data;
else
sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
htonl(m->m_pkthdr.csum_data +
fin->fin_dlen + fin->fin_p));
sum ^= 0xffff;
if (sum != 0) {
fin->fin_cksum = FI_CK_BAD;
fin->fin_flx |= FI_BAD;
DT2(ipf_fi_bad_checkv4sum_sum, fr_info_t *, fin, u_int, sum);
} else {
fin->fin_cksum = FI_CK_SUMOK;
return (0);
}
} else {
if (m->m_pkthdr.csum_flags == CSUM_DELAY_DATA) {
fin->fin_cksum = FI_CK_L4FULL;
return (0);
} else if (m->m_pkthdr.csum_flags == CSUM_TCP ||
m->m_pkthdr.csum_flags == CSUM_UDP ||
m->m_pkthdr.csum_flags == CSUM_IP) {
fin->fin_cksum = FI_CK_L4PART;
return (0);
} else {
manual = 1;
}
}
skipauto:
if (manual != 0) {
if (ipf_checkl4sum(fin) == -1) {
fin->fin_flx |= FI_BAD;
DT2(ipf_fi_bad_checkv4sum_manual, fr_info_t *, fin, u_int, manual);
return (-1);
}
}
#else
if (ipf_checkl4sum(fin) == -1) {
fin->fin_flx |= FI_BAD;
DT2(ipf_fi_bad_checkv4sum_checkl4sum, fr_info_t *, fin, u_int, -1);
return (-1);
}
#endif
return (0);
}
#ifdef USE_INET6
int
ipf_checkv6sum(fr_info_t *fin)
{
if ((fin->fin_flx & FI_NOCKSUM) != 0) {
DT(ipf_checkv6sum_fi_nocksum);
return (0);
}
if ((fin->fin_flx & FI_SHORT) != 0) {
DT(ipf_checkv6sum_fi_short);
return (1);
}
if (fin->fin_cksum != FI_CK_NEEDED) {
DT(ipf_checkv6sum_fi_ck_needed);
return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
}
if (ipf_checkl4sum(fin) == -1) {
fin->fin_flx |= FI_BAD;
DT2(ipf_fi_bad_checkv6sum_checkl4sum, fr_info_t *, fin, u_int, -1);
return (-1);
}
return (0);
}
#endif /* USE_INET6 */
size_t
mbufchainlen(struct mbuf *m0)
{
size_t len;
if ((m0->m_flags & M_PKTHDR) != 0) {
len = m0->m_pkthdr.len;
} else {
struct mbuf *m;
for (m = m0, len = 0; m != NULL; m = m->m_next)
len += m->m_len;
}
return (len);
}
/* ------------------------------------------------------------------------ */
/* Function: ipf_pullup */
/* Returns: NULL == pullup failed, else pointer to protocol header */
/* Parameters: xmin(I)- pointer to buffer where data packet starts */
/* fin(I) - pointer to packet information */
/* len(I) - number of bytes to pullup */
/* */
/* Attempt to move at least len bytes (from the start of the buffer) into a */
/* single buffer for ease of access. Operating system native functions are */
/* used to manage buffers - if necessary. If the entire packet ends up in */
/* a single buffer, set the FI_COALESCE flag even though ipf_coalesce() has */
/* not been called. Both fin_ip and fin_dp are updated before exiting _IF_ */
/* and ONLY if the pullup succeeds. */
/* */
/* We assume that 'xmin' is a pointer to a buffer that is part of the chain */
/* of buffers that starts at *fin->fin_mp. */
/* ------------------------------------------------------------------------ */
ip_t *
ipf_pullup(mb_t *xmin, fr_info_t *fin, int len)
{
int dpoff, ipoff;
mb_t *m = xmin;
ip_t *ip;
if (m == NULL)
return (NULL);
ip = fin->fin_ip;
if ((fin->fin_flx & FI_COALESCE) != 0)
return (ip);
ipoff = fin->fin_ipoff;
if (fin->fin_dp != NULL)
dpoff = (char *)fin->fin_dp - (char *)ip;
else
dpoff = 0;
if (M_LEN(m) < len) {
mb_t *n = *fin->fin_mp;
/*
* Assume that M_PKTHDR is set and just work with what is left
* rather than check..
* Should not make any real difference, anyway.
*/
if (m != n) {
/*
* Record the mbuf that points to the mbuf that we're
* about to go to work on so that we can update the
* m_next appropriately later.
*/
for (; n->m_next != m; n = n->m_next)
;
} else {
n = NULL;
}
#ifdef MHLEN
if (len > MHLEN)
#else
if (len > MLEN)
#endif
{
#ifdef HAVE_M_PULLDOWN
if (m_pulldown(m, 0, len, NULL) == NULL)
m = NULL;
#else
FREE_MB_T(*fin->fin_mp);
m = NULL;
n = NULL;
#endif
} else
{
m = m_pullup(m, len);
}
if (n != NULL)
n->m_next = m;
if (m == NULL) {
/*
* When n is non-NULL, it indicates that m pointed to
* a sub-chain (tail) of the mbuf and that the head
* of this chain has not yet been free'd.
*/
if (n != NULL) {
FREE_MB_T(*fin->fin_mp);
}
*fin->fin_mp = NULL;
fin->fin_m = NULL;
return (NULL);
}
if (n == NULL)
*fin->fin_mp = m;
while (M_LEN(m) == 0) {
m = m->m_next;
}
fin->fin_m = m;
ip = MTOD(m, ip_t *) + ipoff;
fin->fin_ip = ip;
if (fin->fin_dp != NULL)
fin->fin_dp = (char *)fin->fin_ip + dpoff;
if (fin->fin_fraghdr != NULL)
fin->fin_fraghdr = (char *)ip +
((char *)fin->fin_fraghdr -
(char *)fin->fin_ip);
}
if (len == fin->fin_plen)
fin->fin_flx |= FI_COALESCE;
return (ip);
}
int
ipf_inject(fr_info_t *fin, mb_t *m)
{
struct epoch_tracker et;
int error = 0;
NET_EPOCH_ENTER(et);
if (fin->fin_out == 0) {
netisr_dispatch(NETISR_IP, m);
} else {
fin->fin_ip->ip_len = ntohs(fin->fin_ip->ip_len);
fin->fin_ip->ip_off = ntohs(fin->fin_ip->ip_off);
error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
}
NET_EPOCH_EXIT(et);
return (error);
}
VNET_DEFINE_STATIC(pfil_hook_t, ipf_inet_hook);
VNET_DEFINE_STATIC(pfil_hook_t, ipf_inet6_hook);
#define V_ipf_inet_hook VNET(ipf_inet_hook)
#define V_ipf_inet6_hook VNET(ipf_inet6_hook)
int ipf_pfil_unhook(void) {
pfil_remove_hook(V_ipf_inet_hook);
#ifdef USE_INET6
pfil_remove_hook(V_ipf_inet6_hook);
#endif
return (0);
}
int ipf_pfil_hook(void) {
int error, error6;
struct pfil_hook_args pha = {
.pa_version = PFIL_VERSION,
.pa_flags = PFIL_IN | PFIL_OUT,
.pa_modname = "ipfilter",
.pa_rulname = "default-ip4",
.pa_mbuf_chk = ipf_check_wrapper,
.pa_type = PFIL_TYPE_IP4,
};
V_ipf_inet_hook = pfil_add_hook(&pha);
#ifdef USE_INET6
pha.pa_rulname = "default-ip6";
pha.pa_mbuf_chk = ipf_check_wrapper6;
pha.pa_type = PFIL_TYPE_IP6;
V_ipf_inet6_hook = pfil_add_hook(&pha);
#endif
struct pfil_link_args pla = {
.pa_version = PFIL_VERSION,
.pa_flags = PFIL_IN | PFIL_OUT | PFIL_HEADPTR | PFIL_HOOKPTR,
.pa_head = V_inet_pfil_head,
.pa_hook = V_ipf_inet_hook,
};
error = pfil_link(&pla);
error6 = 0;
#ifdef USE_INET6
pla.pa_head = V_inet6_pfil_head;
pla.pa_hook = V_ipf_inet6_hook;
error6 = pfil_link(&pla);
#endif
if (error || error6)
error = ENODEV;
else
error = 0;
return (error);
}
void
ipf_event_reg(void)
{
V_ipf_arrivetag = EVENTHANDLER_REGISTER(ifnet_arrival_event, \
ipf_ifevent, NULL, \
EVENTHANDLER_PRI_ANY);
V_ipf_departtag = EVENTHANDLER_REGISTER(ifnet_departure_event, \
ipf_ifevent, NULL, \
EVENTHANDLER_PRI_ANY);
#if 0
V_ipf_clonetag = EVENTHANDLER_REGISTER(if_clone_event, ipf_ifevent, \
NULL, EVENTHANDLER_PRI_ANY);
#endif
}
void
ipf_event_dereg(void)
{
if (V_ipf_arrivetag != NULL) {
EVENTHANDLER_DEREGISTER(ifnet_arrival_event, V_ipf_arrivetag);
}
if (V_ipf_departtag != NULL) {
EVENTHANDLER_DEREGISTER(ifnet_departure_event, V_ipf_departtag);
}
#if 0
if (V_ipf_clonetag != NULL) {
EVENTHANDLER_DEREGISTER(if_clone_event, V_ipf_clonetag);
}
#endif
}
u_32_t
ipf_random(void)
{
return (arc4random());
}
u_int
ipf_pcksum(fr_info_t *fin, int hlen, u_int sum)
{
struct mbuf *m;
u_int sum2;
int off;
m = fin->fin_m;
off = (char *)fin->fin_dp - (char *)fin->fin_ip;
m->m_data += hlen;
m->m_len -= hlen;
sum2 = in_cksum(fin->fin_m, fin->fin_plen - off);
m->m_len += hlen;
m->m_data -= hlen;
/*
* Both sum and sum2 are partial sums, so combine them together.
*/
sum += ~sum2 & 0xffff;
while (sum > 0xffff)
sum = (sum & 0xffff) + (sum >> 16);
sum2 = ~sum & 0xffff;
return (sum2);
}
#ifdef USE_INET6
u_int
ipf_pcksum6(struct mbuf *m, ip6_t *ip6, u_int32_t off, u_int32_t len)
{
#ifdef _KERNEL
int sum;
if (m->m_len < sizeof(struct ip6_hdr)) {
return (0xffff);
}
sum = in6_cksum(m, ip6->ip6_nxt, off, len);
return (sum);
#else
u_short *sp;
u_int sum;
sp = (u_short *)&ip6->ip6_src;
sum = *sp++; /* ip6_src */
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++; /* ip6_dst */
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
sum += *sp++;
return (ipf_pcksum(fin, off, sum));
#endif
}
#endif
void
ipf_fbsd_kenv_get(ipf_main_softc_t *softc)
{
TUNABLE_INT_FETCH("net.inet.ipf.large_nat",
&softc->ipf_large_nat);
}
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