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freebsd/sys/netinet/ip_fw.c
Jordan K. Hubbard 72e8fea57e Almost 12th hour (the 11th hour was almost an hour ago :-) patches 
from Ugen.
1994-11-08 12:47:29 +00:00

704 lines
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/*
* Copyright (c) 1993 Daniel Boulet
* Copyright (c) 1994 Ugen J.S.Antsilevich
*
* Redistribution and use in source forms, with and without modification,
* are permitted provided that this entire comment appears intact.
*
* Redistribution in binary form may occur without any restrictions.
* Obviously, it would be nice if you gave credit where credit is due
* but requiring it would be too onerous.
*
* This software is provided ``AS IS'' without any warranties of any kind.
*/
/*
* Implement IP packet firewall
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_fw.h>
struct ip_fw *ip_fw_fwd_chain;
struct ip_fw *ip_fw_blk_chain;
int ip_fw_policy=1;
inline
void
print_ip(xaddr)
struct in_addr xaddr;
{
u_long addr = ntohl(xaddr.s_addr);
printf("%d.%d.%d.%d",(addr>>24) & 0xff,
(addr>>16)&0xff,
(addr>>8)&0xff,
addr&0xFF);
}
/*
* Returns 1 if the port is matched by the vector, 0 otherwise
*/
inline
int port_match(portptr,nports,port,range_flag)
u_short *portptr;
int nports;
u_short port;
int range_flag;
{
if ( range_flag ) {
if ( portptr[0] <= port && port <= portptr[1] ) {
return( 1 );
}
nports -= 2;
portptr += 2;
}
while ( nports-- > 0 ) {
if ( *portptr++ == port ) {
return( 1 );
}
}
return(0);
}
/*
* Returns 0 if packet should be dropped, 1 or more if it should be accepted
*/
int ip_fw_chk(ip,chain)
struct ip *ip;
struct ip_fw *chain;
{
struct in_addr src, dst;
char got_proto = 0;
int frwl_proto, proto = 0;
register struct ip_fw *fptr;
u_short src_port = 0, dst_port = 0;
#ifdef IPFIREWALL_VERBOSE
u_short *portptr = (u_short *)&(((u_int *)ip)[ip->ip_hl]);
#endif
if ( chain == NULL ) { /* Is there a frwl chain? */
return(1);
}
src = ip->ip_src;
dst = ip->ip_dst;
#ifdef DEBUG_IPFIREWALL
{
u_short *portptr = (u_short *)&(((u_int *)ip)[ip->ip_hl]);
printf("packet ");
switch(ip->ip_p) {
case IPPROTO_TCP: printf("TCP "); break;
case IPPROTO_UDP: printf("UDP "); break;
case IPPROTO_ICMP: printf("ICMP:%d ",((char *)portptr)[0]&0xff); break;
default: printf("p=%d ",ip->ip_p); break;
}
print_ip(ip->ip_src);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[0]));
}
print_ip(ip->ip_dst);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[1]));
}
printf("\n");
}
#endif
for ( fptr = chain; fptr != NULL; fptr = fptr->next ) {
if ( (src.s_addr & fptr->src_mask.s_addr) == fptr->src.s_addr
&& (dst.s_addr & fptr->dst_mask.s_addr) == fptr->dst.s_addr ) {
if ( (frwl_proto = fptr->flags & IP_FW_F_KIND)
== IP_FW_F_ALL ) {
/* Universal frwl - we've got a match! */
#ifdef DEBUG_IPFIREWALL
printf("universal frwl match\n");
#endif
#ifdef IPFIREWALL_VERBOSE
/*
* VERY ugly piece of code which actually
* makes kernel printf for denyed packets...
* This thingy will be added in more places...
*/
if ( !(fptr->flags & IP_FW_F_ACCEPT) &&
(fptr->flags & IP_FW_F_PRN)) {
printf("ip_fw_chk says no to ");
switch(ip->ip_p) {
case IPPROTO_TCP: printf("TCP "); break;
case IPPROTO_UDP: printf("UDP "); break;
case IPPROTO_ICMP: printf("ICMP:%d ",((char *)portptr)[0]&0xff); break;
default: printf("p=%d ",ip->ip_p); break;
}
print_ip(ip->ip_src);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[0]));
} else {
printf("\n");
}
print_ip(ip->ip_dst);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[1]));
}
printf("\n");
return(0);
}
#endif
return( fptr->flags & IP_FW_F_ACCEPT );
} else {
/* Specific frwl - packet's protocol must match frwl's */
if ( !got_proto ) {
u_short *portptr = (u_short *)&(((u_int *)ip)[ip->ip_hl]);
switch( ip->ip_p ) {
case IPPROTO_TCP:
proto = IP_FW_F_TCP;
src_port = ntohs(portptr[0]); /* first two shorts in TCP */
dst_port = ntohs(portptr[1]); /* are src and dst ports */
break;
case IPPROTO_UDP:
proto = IP_FW_F_UDP;
src_port = ntohs(portptr[0]); /* first two shorts in UDP */
dst_port = ntohs(portptr[1]); /* are src and dst ports */
break;
case IPPROTO_ICMP:
proto = IP_FW_F_ICMP;
break;
default: proto = IP_FW_F_ALL;
#ifdef DEBUG_IPFIREWALL
printf("non TCP/UDP packet\n");
#endif
}
got_proto = 1;
}
if ( proto == frwl_proto ) {
if (
proto == IP_FW_F_ICMP
||
(
(
fptr->n_src_p == 0
||
port_match( &fptr->ports[0],
fptr->n_src_p,
src_port,
fptr->flags & IP_FW_F_SRNG
)
)
&&
(
fptr->n_dst_p == 0
||
port_match( &fptr->ports[fptr->n_src_p],
fptr->n_dst_p,
dst_port,
fptr->flags & IP_FW_F_DRNG
)
)
)
) {
#ifdef IPFIREWALL_VERBOSE
/*
* VERY ugly piece of code which actually
* makes kernel printf for denyed packets...
* This thingy will be added in more places...
*/
if ( !(fptr->flags & IP_FW_F_ACCEPT) &&
(fptr->flags & IP_FW_F_PRN)) {
printf("ip_fw_chk says no to ");
switch(ip->ip_p) {
case IPPROTO_TCP: printf("TCP "); break;
case IPPROTO_UDP: printf("UDP "); break;
case IPPROTO_ICMP: printf("ICMP:%d ",((char *)portptr)[0]&0xff); break;
default: printf("p=%d ",ip->ip_p); break;
}
print_ip(ip->ip_src);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[0]));
} else {
printf("\n");
}
print_ip(ip->ip_dst);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[1]));
}
printf("\n");
return(0);
}
#endif
return( fptr->flags & IP_FW_F_ACCEPT);
}
}
}
}
}
/*
* If we get here then none of the frwls matched.
* So now we relay on policy defined by user-unmatched packet can
* be ever accepted or rejected...
*/
#ifdef IPFIREWALL_VERBOSE
/*
* VERY ugly piece of code which actually
* makes kernel printf for denyed packets...
* This thingy will be added in more places...
*/
if ( !(ip_fw_policy) &&
(fptr->flags & IP_FW_F_PRN)) {
printf("ip_fw_chk says no to ");
switch(ip->ip_p) {
case IPPROTO_TCP: printf("TCP "); break;
case IPPROTO_UDP: printf("UDP "); break;
case IPPROTO_ICMP: printf("ICMP:%d ",((char *)portptr)[0]&0xff); break;
default: printf("p=%d ",ip->ip_p); break;
}
print_ip(ip->ip_src);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[0]));
} else {
printf("\n");
}
print_ip(ip->ip_dst);
if ( ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP ) {
printf(":%d ",ntohs(portptr[1]));
}
printf("\n");
return(0);
}
#endif
return(ip_fw_policy);
}
static
void
free_fw_chain(chainptr)
struct ip_fw **chainptr;
{
int s=splnet();
while ( *chainptr != NULL ) {
struct ip_fw *ftmp;
ftmp = *chainptr;
*chainptr = ftmp->next;
free(ftmp,M_SOOPTS);
}
splx(s);
}
static
int
add_to_chain(chainptr,frwl)
struct ip_fw **chainptr;
struct ip_fw *frwl;
{
struct ip_fw *ftmp;
struct ip_fw *chtmp=NULL;
struct ip_fw *chtmp_prev=NULL;
int s=splnet();
u_long m_src_mask,m_dst_mask;
u_long n_sa,n_da,o_sa,o_da,o_sm,o_dm,n_sm,n_dm;
u_short n_sr,n_dr,o_sr,o_dr;
u_short oldkind,newkind;
int addb4=0;
int n_o,n_n;
ftmp = malloc( sizeof(struct ip_fw), M_SOOPTS, M_DONTWAIT );
if ( ftmp == NULL ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: malloc said no\n");
#endif
splx(s);
return( ENOSPC );
}
bcopy( frwl, ftmp, sizeof( struct ip_fw ) );
ftmp->next = NULL;
if (*chainptr==NULL)
{
*chainptr=ftmp;
}
else
{
chtmp_prev=NULL;
for (chtmp=*chainptr;chtmp!=NULL;chtmp=chtmp->next) {
addb4=0;
newkind=ftmp->flags & IP_FW_F_KIND;
oldkind=chtmp->flags & IP_FW_F_KIND;
if (newkind!=IP_FW_F_ALL
&& oldkind!=IP_FW_F_ALL
&& oldkind!=newkind)
continue;
/*
* Very very *UGLY* code...
* Sorry,but i had to do this....
*/
n_sa=ntohl(ftmp->src.s_addr);
n_da=ntohl(ftmp->dst.s_addr);
n_sm=ntohl(ftmp->src_mask.s_addr);
n_dm=ntohl(ftmp->dst_mask.s_addr);
o_sa=ntohl(chtmp->src.s_addr);
o_da=ntohl(chtmp->dst.s_addr);
o_sm=ntohl(chtmp->src_mask.s_addr);
o_dm=ntohl(chtmp->dst_mask.s_addr);
m_src_mask = o_sm & n_sm;
m_dst_mask = o_dm & n_dm;
if ((o_sa & m_src_mask) == (n_sa & m_src_mask)) {
if (n_sm > o_sm)
addb4++;
if (n_sm < o_sm)
addb4--;
}
if ((o_da & m_dst_mask) == (n_da & m_dst_mask)) {
if (n_dm > o_dm)
addb4++;
if (n_dm < o_dm)
addb4--;
}
if (((o_da & o_dm) == (n_da & n_dm))
&&((o_sa & o_sm) == (n_sa & n_sm)))
{
if (newkind!=IP_FW_F_ALL &&
oldkind==IP_FW_F_ALL)
addb4++;
if (newkind==oldkind && (oldkind==IP_FW_F_TCP
|| oldkind==IP_FW_F_UDP)) {
/*
* Here the main ide is to check the size
* of port range which the frwl covers
* We actually don't check their values but
* just the wideness of range they have
* so that less wide ranges or single ports
* go first and wide ranges go later. No ports
* at all treated as a range of maximum number
* of ports.
*/
if (ftmp->flags & IP_FW_F_SRNG)
n_sr=ftmp->ports[1]-ftmp->ports[0];
else
n_sr=(ftmp->n_src_p)?
ftmp->n_src_p : USHRT_MAX;
if (chtmp->flags & IP_FW_F_SRNG)
o_sr=chtmp->ports[1]-chtmp->ports[0];
else
o_sr=(chtmp->n_src_p)?
chtmp->n_src_p : USHRT_MAX;
if (n_sr<o_sr)
addb4++;
if (n_sr>o_sr)
addb4--;
n_n=ftmp->n_src_p;
n_o=chtmp->n_src_p;
/*
* Actually this cannot happen as the frwl control
* procedure checks for number of ports in source and
* destination range but we will try to be more safe.
*/
if ((n_n>(IP_FW_MAX_PORTS-2)) ||
(n_o>(IP_FW_MAX_PORTS-2)))
goto skip_check;
if (ftmp->flags & IP_FW_F_DRNG)
n_dr=ftmp->ports[n_n+1]-ftmp->ports[n_n];
else
n_dr=(ftmp->n_dst_p)?
ftmp->n_dst_p : USHRT_MAX;
if (chtmp->flags & IP_FW_F_DRNG)
o_dr=chtmp->ports[n_o+1]-chtmp->ports[n_o];
else
o_dr=(chtmp->n_dst_p)?
chtmp->n_dst_p : USHRT_MAX;
if (n_dr<o_dr)
addb4++;
if (n_dr>o_dr)
addb4--;
skip_check:
}
}
if (addb4>0) {
if (chtmp_prev) {
chtmp_prev->next=ftmp;
ftmp->next=chtmp;
} else {
*chainptr=ftmp;
ftmp->next=chtmp;
}
splx(s);
return 0;
}
chtmp_prev=chtmp;
}
if (chtmp_prev)
chtmp_prev->next=ftmp;
else
#define wrong
#ifdef wrong
*chainptr=ftmp;
#else
panic("Can't happen");
#endif
#undef wrong
}
splx(s);
return(0);
}
static
int
del_from_chain(chainptr,frwl)
struct ip_fw **chainptr;
struct ip_fw *frwl;
{
struct ip_fw *ftmp,*ltmp;
u_short tport1,tport2,tmpnum;
char matches,was_found;
int s=splnet();
ftmp=*chainptr;
if ( ftmp == NULL ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: chain is empty\n");
#endif
splx(s);
return( EINVAL );
}
ltmp=NULL;
was_found=0;
while( ftmp != NULL )
{
matches=1;
if ((bcmp(&ftmp->src,&frwl->src,sizeof(struct in_addr)))
|| (bcmp(&ftmp->src_mask,&frwl->src_mask,sizeof(struct in_addr)))
|| (bcmp(&ftmp->dst,&frwl->dst,sizeof(struct in_addr)))
|| (bcmp(&ftmp->dst_mask,&frwl->dst_mask,sizeof(struct in_addr)))
|| (ftmp->flags!=frwl->flags))
matches=0;
tport1=ftmp->n_src_p+ftmp->n_dst_p;
tport2=frwl->n_src_p+frwl->n_dst_p;
if (tport1!=tport2)
matches=0;
else
if (tport1!=0)
{
for (tmpnum=0;tmpnum < tport1 && tmpnum < IP_FW_MAX_PORTS;tmpnum++)
if (ftmp->ports[tmpnum]!=frwl->ports[tmpnum])
matches=0;
}
if(matches)
{
was_found=1;
if (ltmp)
{
ltmp->next=ftmp->next;
free(ftmp,M_SOOPTS);
ftmp=ltmp->next;
}
else
{
*chainptr=ftmp->next;
free(ftmp,M_SOOPTS);
ftmp=*chainptr;
}
}
else
{
ltmp = ftmp;
ftmp = ftmp->next;
}
}
splx(s);
if (was_found) return 0;
else return(EINVAL);
}
int
ip_fw_ctl(stage,m)
int stage;
struct mbuf *m;
{
int *tmp_policy_ptr;
if ( stage == IP_FW_FLUSH )
{
free_fw_chain(&ip_fw_blk_chain);
free_fw_chain(&ip_fw_fwd_chain);
return(0);
}
if ( m == 0 )
{
printf("ip_fw_ctl: NULL mbuf ptr\n");
return( EINVAL );
}
if ( stage == IP_FW_POLICY )
{
tmp_policy_ptr=mtod(m,int *);
if ((*tmp_policy_ptr)!=1 && (*tmp_policy_ptr)!=0)
return ( EINVAL );
ip_fw_policy=*tmp_policy_ptr;
return 0;
}
if ( stage == IP_FW_CHK_BLK || stage == IP_FW_CHK_FWD ) {
struct ip *ip;
if ( m->m_len < sizeof(struct ip) + 2 * sizeof(u_short) ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: mbuf len=%d, want at least %d\n",m->m_len,sizeof(struct ip) + 2 * sizeof(u_short));
#endif
return( EINVAL );
}
ip = mtod(m,struct ip *);
if ( ip->ip_hl != sizeof(struct ip) / sizeof(int) ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: ip->ip_hl=%d, want %d\n",ip->ip_hl,sizeof(struct ip)/sizeof(int));
#endif
return( EINVAL );
}
if ( ip_fw_chk(ip,
stage == IP_FW_CHK_BLK ?
ip_fw_blk_chain : ip_fw_fwd_chain )
)
return(0);
else {
return(EACCES);
}
} else if ( stage == IP_FW_ADD_BLK
|| stage == IP_FW_ADD_FWD
|| stage == IP_FW_DEL_BLK
|| stage == IP_FW_DEL_FWD
) {
struct ip_fw *frwl;
if ( m->m_len != sizeof(struct ip_fw) ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: len=%d, want %d\n",m->m_len,sizeof(struct ip_fw));
#endif
return( EINVAL );
}
frwl = mtod(m,struct ip_fw*);
if ( (frwl->flags & ~IP_FW_F_MASK) != 0 ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: undefined flag bits set (flags=%x)\n",frwl->flags);
#endif
return( EINVAL );
}
if ( (frwl->flags & IP_FW_F_SRNG) && frwl->n_src_p < 2 ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: src range set but n_src_p=%d\n",frwl->n_src_p);
#endif
return( EINVAL );
}
if ( (frwl->flags & IP_FW_F_DRNG) && frwl->n_dst_p < 2 ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: dst range set but n_dst_p=%d\n",frwl->n_dst_p);
#endif
return( EINVAL );
}
if ( frwl->n_src_p + frwl->n_dst_p > IP_FW_MAX_PORTS ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: too many ports (%d+%d)\n",frwl->n_src_p,frwl->n_dst_p);
#endif
return( EINVAL );
}
#if 0
if ( (frwl->flags & IP_FW_F_KIND) == IP_FW_F_ICMP ) {
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: request for unsupported ICMP frwling\n");
#endif
return( EINVAL );
}
#endif
if ( stage == IP_FW_ADD_BLK )
{
return( add_to_chain(&ip_fw_blk_chain,frwl));
}
if ( stage == IP_FW_ADD_FWD )
{
return( add_to_chain(&ip_fw_fwd_chain,frwl));
}
if ( stage == IP_FW_DEL_BLK )
{
return( del_from_chain(&ip_fw_blk_chain,frwl));
}
if ( stage == IP_FW_DEL_FWD )
{
return( del_from_chain(&ip_fw_fwd_chain,frwl));
}
}
#ifdef DEBUG_IPFIREWALL
printf("ip_fw_ctl: unknown request %d\n",stage);
#endif
return(EINVAL);
}
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