blob: e2f8219d4cde24b21eee6510f5ef36432edd959e [file] [log] [blame] [raw]
/*
* Copyright (C) 1993-2003 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*/
#if !defined(lint)
static const char sccsid[] = "@(#)ip_fil.c 2.41 6/5/96 (C) 1993-2000 Darren Reed";
static const char rcsid[] = "@(#)$Id$";
#endif
#if defined(KERNEL) || defined(_KERNEL)
# undef KERNEL
# undef _KERNEL
# define KERNEL 1
# define _KERNEL 1
#endif
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/systm.h>
#include <sys/dirent.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/timeout.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.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_timer.h>
#include <netinet/tcp_var.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"
#ifdef IPFILTER_SYNC
#include "netinet/ip_sync.h"
#endif
#ifdef IPFILTER_SCAN
#include "netinet/ip_scan.h"
#endif
#include "netinet/ip_pool.h"
#include <sys/kernel.h>
extern int ip_optcopy __P((struct ip *, struct ip *));
#ifdef IPFILTER_M_IPFILTER
MALLOC_DEFINE(M_IPFILTER, "IP Filter", "IP Filter packet filter data structures");
#endif
extern struct protosw inetsw[];
extern int ipforwarding;
#ifdef USE_INET6
extern int ip6_getpmtu(struct route_in6 *, struct route_in6 *,
struct ifnet *, struct in6_addr *, u_long *);
#endif
static int (*fr_savep) __P((ip_t *, int, void *, int, struct mbuf **));
static int fr_send_ip __P((fr_info_t *, mb_t *, mb_t **));
#ifdef USE_INET6
static int ipfr_fastroute6 __P((struct mbuf *, struct mbuf **,
fr_info_t *, frdest_t *));
#endif
#include <sys/timeout.h>
struct timeout fr_slowtimer_ch;
#include <sys/conf.h>
/*
* We provide the fr_checkp name just to minimize changes later.
*/
int (*fr_checkp) __P((ip_t *ip, int hlen, void *ifp, int out, mb_t **mp));
#if defined(IPFILTER_LKM)
int iplidentify(s)
char *s;
{
if (strcmp(s, "ipl") == 0)
return 1;
return 0;
}
#endif /* IPFILTER_LKM */
int ipfattach()
{
int s;
SPL_NET(s);
if ((fr_running > 0) || (fr_checkp == fr_check)) {
printf("IP Filter: already initialized\n");
SPL_X(s);
return EBUSY;
}
if (fr_initialise() < 0) {
SPL_X(s);
return EIO;
}
bzero((char *)frcache, sizeof(frcache));
fr_savep = fr_checkp;
fr_checkp = fr_check;
if (fr_control_forwarding & 1)
ipforwarding = 1;
SPL_X(s);
timeout_set(&fr_slowtimer_ch, fr_slowtimer, NULL);
timeout_add(&fr_slowtimer_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT);
return 0;
}
/*
* Disable the filter by removing the hooks from the IP input/output
* stream.
*/
int ipfdetach()
{
int s;
SPL_NET(s);
timeout_del(&fr_slowtimer_ch);
fr_deinitialise();
fr_checkp = fr_savep;
(void) frflush(IPL_LOGIPF, 0, FR_INQUE|FR_OUTQUE|FR_INACTIVE);
(void) frflush(IPL_LOGIPF, 0, FR_INQUE|FR_OUTQUE);
if (fr_control_forwarding & 2)
ipforwarding = 0;
SPL_X(s);
return 0;
}
/*
* Filter ioctl interface.
*/
int iplioctl(dev, cmd, data, mode , p)
struct proc *p;
dev_t dev;
u_long cmd;
caddr_t data;
int mode;
{
int error = 0, unit = 0;
SPL_INT(s);
if ((securelevel >= 2) && (mode & FWRITE))
return EPERM;
unit = GET_MINOR(dev);
if ((IPL_LOGMAX < unit) || (unit < 0))
return ENXIO;
if (fr_running <= 0) {
if (unit != IPL_LOGIPF)
return EIO;
if (cmd != SIOCIPFGETNEXT && cmd != SIOCIPFGET &&
cmd != SIOCIPFSET && cmd != SIOCFRENB &&
cmd != SIOCGETFS && cmd != SIOCGETFF)
return EIO;
}
SPL_NET(s);
error = fr_ioctlswitch(unit, data, cmd, mode, p->p_cred->p_ruid, p);
if (error != -1) {
SPL_X(s);
return error;
}
SPL_X(s);
return error;
}
#if 0
void fr_forgetifp(ifp)
void *ifp;
{
register frentry_t *f;
WRITE_ENTER(&ipf_mutex);
for (f = ipacct[0][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
for (f = ipacct[1][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
for (f = ipfilter[0][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
for (f = ipfilter[1][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
#ifdef USE_INET6
for (f = ipacct6[0][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
for (f = ipacct6[1][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
for (f = ipfilter6[0][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
for (f = ipfilter6[1][fr_active]; (f != NULL); f = f->fr_next)
if (f->fr_ifa == ifp)
f->fr_ifa = (void *)-1;
#endif
RWLOCK_EXIT(&ipf_mutex);
fr_natsync(ifp);
}
#endif
/*
* routines below for saving IP headers to buffer
*/
int iplopen(dev, flags, devtype, p)
dev_t dev;
int flags;
int devtype;
struct proc *p;
{
u_int unit = GET_MINOR(dev);
int error;
if (IPL_LOGMAX < unit) {
error = ENXIO;
} else {
switch (unit)
{
case IPL_LOGIPF :
case IPL_LOGNAT :
case IPL_LOGSTATE :
case IPL_LOGAUTH :
#ifdef IPFILTER_LOOKUP
case IPL_LOGLOOKUP :
#endif
#ifdef IPFILTER_SYNC
case IPL_LOGSYNC :
#endif
#ifdef IPFILTER_SCAN
case IPL_LOGSCAN :
#endif
error = 0;
break;
default :
error = ENXIO;
break;
}
error = 0;
}
return error;
}
int iplclose(dev, flags, devtype, p)
dev_t dev;
int flags;
int devtype;
struct proc *p;
{
u_int unit = GET_MINOR(dev);
if (IPL_LOGMAX < unit)
unit = ENXIO;
else
unit = 0;
return unit;
}
/*
* iplread/ipllog
* both of these must operate with at least splnet() lest they be
* called during packet processing and cause an inconsistancy to appear in
* the filter lists.
*/
int iplread(dev, uio, ioflag)
dev_t dev;
register struct uio *uio;
int ioflag;
{
if (fr_running < 1)
return EIO;
# ifdef IPFILTER_SYNC
if (GET_MINOR(dev) == IPL_LOGSYNC)
return ipfsync_read(uio);
# endif
#ifdef IPFILTER_LOG
return ipflog_read(GET_MINOR(dev), uio);
#else
return ENXIO;
#endif
}
/*
* iplwrite
* both of these must operate with at least splnet() lest they be
* called during packet processing and cause an inconsistancy to appear in
* the filter lists.
*/
#if (BSD >= 199306)
int iplwrite(dev, uio, ioflag)
int ioflag;
#else
int iplwrite(dev, uio)
#endif
dev_t dev;
register struct uio *uio;
{
if (fr_running < 1)
return EIO;
#ifdef IPFILTER_SYNC
if (GET_MINOR(dev) == IPL_LOGSYNC)
return ipfsync_write(uio);
#endif
return ENXIO;
}
/*
* fr_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 fr_send_reset(fin)
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 (fr_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_DONTWAIT, MT_HEADER);
#else
MGET(m, M_DONTWAIT, MT_HEADER);
#endif
if (m == NULL)
return -1;
if (sizeof(*tcp2) + hlen > MHLEN) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
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->th_flags & TH_ACK) {
tcp2->th_seq = tcp->th_ack;
tcp2->th_flags = 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);
tcp2->th_flags = TH_RST|TH_ACK;
}
TCP_X2_A(tcp2, 0);
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;
ip6->ip6_dst = fin->fin_src6;
tcp2->th_sum = in6_cksum(m, IPPROTO_TCP,
sizeof(*ip6), sizeof(*tcp2));
return fr_send_ip(fin, m, &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 = hlen + sizeof(*tcp2);
return fr_send_ip(fin, m, &m);
}
static int fr_send_ip(fin, m, mpp)
fr_info_t *fin;
mb_t *m, **mpp;
{
fr_info_t fnew;
ip_t *ip, *oip;
int hlen;
ip = mtod(m, ip_t *);
bzero((char *)&fnew, sizeof(fnew));
IP_V_A(ip, fin->fin_v);
switch (fin->fin_v)
{
case 4 :
fnew.fin_v = 4;
oip = fin->fin_ip;
IP_HL_A(ip, sizeof(*oip) >> 2);
ip->ip_tos = oip->ip_tos;
ip->ip_id = fr_nextipid(fin);
ip->ip_off = ip_mtudisc ? IP_DF : 0;
ip->ip_ttl = ip_defttl;
ip->ip_sum = 0;
hlen = sizeof(*oip);
break;
#ifdef USE_INET6
case 6 :
{
ip6_t *ip6 = (ip6_t *)ip;
ip6->ip6_vfc = 0x60;
ip6->ip6_hlim = IPDEFTTL;
fnew.fin_v = 6;
hlen = sizeof(*ip6);
break;
}
#endif
default :
return EINVAL;
}
#ifdef IPSEC
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 = mpp;
fnew.fin_hlen = hlen;
fnew.fin_dp = (char *)ip + hlen;
(void) fr_makefrip(hlen, ip, &fnew);
return fr_fastroute(m, mpp, &fnew, NULL);
}
int fr_send_icmp_err(type, fin, dst)
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;
void *ifp;
#ifdef USE_INET6
ip6_t *ip6;
struct in6_addr dst6;
#endif
ip_t *ip, *ip2;
if ((type < 0) || (type > ICMP_MAXTYPE))
return -1;
code = fin->fin_icode;
#ifdef USE_INET6
if ((code < 0) || (code > sizeof(icmptoicmp6unreach)/sizeof(int)))
return -1;
#endif
if (fr_checkl4sum(fin) == -1)
return -1;
#ifdef MGETHDR
MGETHDR(m, M_DONTWAIT, MT_HEADER);
#else
MGET(m, M_DONTWAIT, MT_HEADER);
#endif
if (m == NULL)
return -1;
avail = MHLEN;
xtra = 0;
hlen = 0;
ohlen = 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 (fr_ifpaddr(4, FRI_NORMAL, ifp,
&dst4, NULL) == -1) {
FREE_MB_T(m);
return -1;
}
} else
dst4.s_addr = fin->fin_daddr;
hlen = sizeof(ip_t);
ohlen = fin->fin_hlen;
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);
type = icmptoicmp6types[type];
if (type == ICMP6_DST_UNREACH)
code = icmptoicmp6unreach[code];
if (hlen + sizeof(*icmp) + max_linkhdr +
fin->fin_plen > avail) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
FREE_MB_T(m);
return -1;
}
avail = MCLBYTES;
}
xtra = MIN(fin->fin_plen,
avail - hlen - sizeof(*icmp) - max_linkhdr);
if (dst == 0) {
if (fr_ifpaddr(6, FRI_NORMAL, ifp,
(struct in_addr *)&dst6, NULL) == -1) {
FREE_MB_T(m);
return -1;
}
} else
dst6 = fin->fin_dst6;
}
#endif
else {
FREE_MB_T(m);
return -1;
}
iclen = hlen + sizeof(*icmp);
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;
bzero((char *)ip, iclen);
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 && ifp)
icmp->icmp_nextmtu = htons(((struct ifnet *)ifp)->if_mtu);
#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;
ip6->ip6_dst = fin->fin_src6;
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
{
ip2->ip_len = htons(ip2->ip_len);
ip2->ip_off = htons(ip2->ip_off);
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 = iclen;
ip->ip_p = IPPROTO_ICMP;
}
err = fr_send_ip(fin, m, &m);
return err;
}
#if !defined(IPFILTER_LKM)
void iplinit __P((void));
void
iplinit()
{
if (ipfattach() != 0)
printf("IP Filter failed to attach\n");
else
fr_running = 1;
ip_init();
}
#endif /* ! IPFILTER_LKM */
/*
* m0 - pointer to mbuf where the IP packet starts
* mpp - pointer to the mbuf pointer that is the start of the mbuf chain
*/
int fr_fastroute(m0, mpp, fin, fdp)
mb_t *m0, **mpp;
fr_info_t *fin;
frdest_t *fdp;
{
register struct ip *ip, *mhip;
register struct mbuf *m = *mpp;
register struct route *ro;
int len, off, error = 0, hlen, code;
struct ifnet *ifp, *sifp;
struct sockaddr_in *dst;
struct route iproute;
u_short ip_off;
frentry_t *fr;
#ifdef USE_INET6
if (fin->fin_v == 6) {
/*
* currently "to <if>" and "to <if>:ip#" are not supported
* for IPv6
*/
error = ipfr_fastroute6(m, mpp, fin, fdp);
if ((error != 0) && (*mpp != NULL)) {
FREE_MB_T(*mpp);
*mpp = NULL;
}
return error;
}
#endif
hlen = fin->fin_hlen;
ip = mtod(m0, struct ip *);
/*
* Route packet.
*/
ro = &iproute;
bzero((caddr_t)ro, sizeof (*ro));
dst = (struct sockaddr_in *)&ro->ro_dst;
dst->sin_family = AF_INET;
dst->sin_addr = ip->ip_dst;
fr = fin->fin_fr;
if (fdp != NULL)
ifp = fdp->fd_ifp;
else
ifp = fin->fin_ifp;
if ((ifp == NULL) && (!fr || !(fr->fr_flags & FR_FASTROUTE))) {
error = -2;
goto bad;
}
if ((fdp != NULL) && (fdp->fd_ip.s_addr != 0))
dst->sin_addr = fdp->fd_ip;
dst->sin_len = sizeof(*dst);
rtalloc(ro);
if ((ifp == NULL) && (ro->ro_rt != NULL))
ifp = ro->ro_rt->rt_ifp;
if ((ro->ro_rt == NULL) || (ifp == NULL)) {
if (in_localaddr(ip->ip_dst))
error = EHOSTUNREACH;
else
error = ENETUNREACH;
goto bad;
}
if (ro->ro_rt->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
if (ro->ro_rt)
ro->ro_rt->rt_use++;
/*
* 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) fr_acctpkt(fin, NULL);
fin->fin_fr = NULL;
if (!fr || !(fr->fr_flags & FR_RETMASK)) {
u_32_t pass;
(void) fr_checkstate(fin, &pass);
}
switch (fr_checknatout(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 (ip->ip_len <= ifp->if_mtu) {
int i = 0;
#ifdef MCLISREFERENCED
if ((m->m_flags & (M_EXT|M_CLUSTER)) == M_EXT &&
MCLISREFERENCED(m))
#else
if (m->m_flags & M_EXT)
#endif
i = 1;
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
if (!ip->ip_sum)
ip->ip_sum = in_cksum(m, hlen);
error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst,
ro->ro_rt);
if (i) {
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
}
goto done;
}
/*
* Too large for interface; fragment if possible.
* Must be able to put at least 8 bytes per fragment.
*/
ip_off = 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 < ip->ip_len; off += len) {
#ifdef MGETHDR
MGETHDR(m, M_DONTWAIT, MT_HEADER);
#else
MGET(m, M_DONTWAIT, MT_HEADER);
#endif
if (m == 0) {
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 >= ip->ip_len)
len = ip->ip_len - off;
else
mhip->ip_off |= IP_MF;
mhip->ip_len = htons((u_short)(len + mhlen));
m->m_next = m_copy(m0, off, len);
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;
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,
(struct sockaddr *)dst, ro->ro_rt);
else
FREE_MB_T(m);
}
}
done:
if (!error)
fr_frouteok[0]++;
else
fr_frouteok[1]++;
if (ro->ro_rt) {
RTFREE(ro->ro_rt);
}
*mpp = NULL;
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) fr_send_icmp_err(ICMP_UNREACH, fin, 1);
fin->fin_ifp = sifp;
fin->fin_icode = code;
}
FREE_MB_T(m);
goto done;
}
#if defined(USE_INET6)
/*
* This is the IPv6 specific fastroute code. It doesn't clean up the mbuf's
* or ensure that it is an IPv6 packet that is being forwarded, those are
* expected to be done by the called (ipfr_fastroute).
*/
static int ipfr_fastroute6(m0, mpp, fin, fdp)
struct mbuf *m0, **mpp;
fr_info_t *fin;
frdest_t *fdp;
{
struct route_in6 ip6route;
struct sockaddr_in6 *dst6;
struct route_in6 *ro;
struct ifnet *ifp;
frentry_t *fr;
#if defined(OpenBSD) && (OpenBSD >= 200211)
struct route_in6 *ro_pmtu = NULL;
struct in6_addr finaldst;
ip6_t *ip6;
#endif
u_long mtu;
int error;
ro = &ip6route;
fr = fin->fin_fr;
bzero((caddr_t)ro, sizeof(*ro));
dst6 = (struct sockaddr_in6 *)&ro->ro_dst;
dst6->sin6_family = AF_INET6;
dst6->sin6_len = sizeof(struct sockaddr_in6);
dst6->sin6_addr = fin->fin_fi.fi_dst.in6;
if (fdp != NULL)
ifp = fdp->fd_ifp;
else
ifp = fin->fin_ifp;
if (fdp != NULL) {
if (IP6_NOTZERO(&fdp->fd_ip6))
dst6->sin6_addr = fdp->fd_ip6.in6;
}
rtalloc((struct route *)ro);
if ((ifp == NULL) && (ro->ro_rt != NULL))
ifp = ro->ro_rt->rt_ifp;
if ((ro->ro_rt == NULL) || (ifp == NULL) ||
(ifp != ro->ro_rt->rt_ifp)) {
error = EHOSTUNREACH;
} else {
if (ro->ro_rt->rt_flags & RTF_GATEWAY)
dst6 = (struct sockaddr_in6 *)ro->ro_rt->rt_gateway;
ro->ro_rt->rt_use++;
#if defined(OpenBSD) && (OpenBSD >= 200211)
ip6 = mtod(m0, ip6_t *);
ro_pmtu = ro;
finaldst = ip6->ip6_dst;
error = ip6_getpmtu(ro_pmtu, ro, ifp, &finaldst, &mtu);
if (error == 0) {
#else
mtu = nd_ifinfo[ifp->if_index].linkmtu;
#endif
if (m0->m_pkthdr.len <= mtu) {
error = nd6_output(ifp, fin->fin_ifp, *mpp,
dst6, ro->ro_rt);
*mpp = NULL;
} else {
error = EMSGSIZE;
}
#if defined(OpenBSD) && (OpenBSD >= 200211)
}
#endif
}
if (ro->ro_rt != NULL) {
RTFREE(ro->ro_rt);
}
return error;
}
#endif
int fr_verifysrc(fin)
fr_info_t *fin;
{
struct sockaddr_in *dst;
struct route iproute;
bzero((char *)&iproute, sizeof(iproute));
dst = (struct sockaddr_in *)&iproute.ro_dst;
dst->sin_len = sizeof(*dst);
dst->sin_family = AF_INET;
dst->sin_addr = fin->fin_src;
rtalloc(&iproute);
if (iproute.ro_rt == NULL)
return 0;
return (fin->fin_ifp == iproute.ro_rt->rt_ifp);
}
/*
* return the first IP Address associated with an interface
*/
int fr_ifpaddr(v, atype, ifptr, inp, inpmask)
int v, atype;
void *ifptr;
struct in_addr *inp, *inpmask;
{
#ifdef USE_INET6
struct in6_addr *inp6 = NULL;
#endif
struct sockaddr *sock, *mask;
struct sockaddr_in *sin;
struct ifaddr *ifa;
struct ifnet *ifp;
if ((ifptr == NULL) || (ifptr == (void *)-1))
return -1;
ifp = ifptr;
if (v == 4)
inp->s_addr = 0;
#ifdef USE_INET6
else if (v == 6)
bzero((char *)inp, sizeof(struct in6_addr));
#endif
ifa = ifp->if_addrlist.tqh_first;
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)) {
inp6 = &((struct sockaddr_in6 *)sin)->sin6_addr;
if (!IN6_IS_ADDR_LINKLOCAL(inp6) &&
!IN6_IS_ADDR_LOOPBACK(inp6))
break;
}
#endif
ifa = ifa->ifa_list.tqe_next;
if (ifa != NULL)
sock = ifa->ifa_addr;
}
if (ifa == NULL || sock == NULL)
return -1;
mask = ifa->ifa_netmask;
if (atype == FRI_BROADCAST)
sock = ifa->ifa_broadaddr;
else if (atype == FRI_PEERADDR)
sock = ifa->ifa_dstaddr;
#ifdef USE_INET6
if (v == 6)
return fr_ifpfillv6addr(atype, (struct sockaddr_in6 *)sock,
(struct sockaddr_in6 *)mask,
inp, inpmask);
#endif
return fr_ifpfillv4addr(atype, (struct sockaddr_in *)sock,
(struct sockaddr_in *)mask, inp, inpmask);
}
u_32_t fr_newisn(fin)
fr_info_t *fin;
{
u_32_t newiss;
#if OpenBSD > 200012
newiss = tcp_rndiss_next();
#else
static iss_seq_off = 0;
u_char hash[16];
MD5_CTX ctx;
/*
* Compute the base value of the ISS. It is a hash
* of (saddr, sport, daddr, dport, secret).
*/
MD5Init(&ctx);
MD5Update(&ctx, (u_char *) &fin->fin_fi.fi_src,
sizeof(fin->fin_fi.fi_src));
MD5Update(&ctx, (u_char *) &fin->fin_fi.fi_dst,
sizeof(fin->fin_fi.fi_dst));
MD5Update(&ctx, (u_char *) &fin->fin_dat, sizeof(fin->fin_dat));
MD5Update(&ctx, ipf_iss_secret, sizeof(ipf_iss_secret));
MD5Final(hash, &ctx);
memcpy(&newiss, hash, sizeof(newiss));
/*
* Now increment our "timer", and add it in to
* the computed value.
*
* XXX Use `addin'?
* XXX TCP_ISSINCR too large to use?
*/
iss_seq_off += 0x00010000;
newiss += iss_seq_off;
#endif
return newiss;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_nextipid */
/* Returns: int - 0 == success, -1 == error (packet should be droppped) */
/* Parameters: fin(I) - pointer to packet information */
/* */
/* Returns the next IPv4 ID to use for this packet. */
/* ------------------------------------------------------------------------ */
u_short fr_nextipid(fin)
fr_info_t *fin;
{
u_short id;
id = htons(ip_randomid());
return id;
}
INLINE void fr_checkv4sum(fin)
fr_info_t *fin;
{
#ifdef M_CSUM_TCP_UDP_BAD
int manual, pflag, cflags, active;
mb_t *m;
if ((fin->fin_flx & FI_NOCKSUM) != 0)
return;
if (fin->fin_cksum != 0)
return;
manual = 0;
m = fin->fin_m;
if (m == NULL) {
manual = 1;
goto skipauto;
}
switch (fin->fin_p)
{
case IPPROTO_UDP :
active = M_TCP_CSUM_IN_OK | M_TCP_CSUM_IN_BAD;
pflag = M_TCP_CSUM_IN_OK;
break;
case IPPROTO_TCP :
active = M_UDP_CSUM_IN_OK | M_UDP_CSUM_IN_BAD;
pflag = M_UDP_CSUM_IN_OK;
break;
default :
pflag = 0;
manual = 1;
break;
}
cflags = m->m_pkthdr.csum & active;
if (pflag != 0) {
if (cflags == active)) {
fin->fin_flx |= FI_BAD
fin->fin_cksum = -1;
} else if (cflags == pflag) {
fin->fin_cksum = 1;
} else {
manual = 1;
}
}
skipauto:
# ifdef IPFILTER_CKSUM
if (manual != 0) {
if (fr_checkl4sum(fin) == -1)
fin->fin_flx |= FI_BAD;
else
m->m_pkthdr.csum |= pflag;
}
# else
;
# endif
#else
# ifdef IPFILTER_CKSUM
if (fr_checkl4sum(fin) == -1)
fin->fin_flx |= FI_BAD;
# endif
#endif
}
#ifdef USE_INET6
INLINE void fr_checkv6sum(fin)
fr_info_t *fin;
{
fr_checkv4sum(fin);
}
#endif
size_t mbufchainlen(m0)
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: fr_pullup */
/* Returns: NULL == pullup failed, else pointer to protocol header */
/* Parameters: m(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 fr_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 'min' is a pointer to a buffer that is part of the chain */
/* of buffers that starts at *fin->fin_mp. */
/* ------------------------------------------------------------------------ */
void *fr_pullup(xmin, fin, len)
mb_t *xmin;
fr_info_t *fin;
int len;
{
int out = fin->fin_out, dpoff, ipoff;
mb_t *m = xmin;
char *ip;
if (m == NULL)
return NULL;
ip = (char *)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;
ATOMIC_INCL(frstats[out].fr_pull[1]);
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, char *) + ipoff;
ATOMIC_INCL(frstats[out].fr_pull[0]);
fin->fin_ip = (ip_t *)ip;
if (fin->fin_dp != NULL)
fin->fin_dp = (char *)fin->fin_ip + dpoff;
}
if (len == fin->fin_plen)
fin->fin_flx |= FI_COALESCE;
return ip;
}
int ipf_inject(fin, m)
fr_info_t *fin;
mb_t *m;
{
int error;
if (fin->fin_out == 0) {
struct ifqueue *ifq;
ifq = &ipintrq;
if (IF_QFULL(ifq)) {
IF_DROP(ifq);
FREE_MB_T(m);
error = ENOBUFS;
} else {
IF_ENQUEUE(ifq, m);
error = 0;
}
} else {
error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
}
return error;
}