/*
* IP firewalling code. This is taken from 4.4BSD. Please note the
* copyright message below. As per the GPL it must be maintained
* and the licenses thus do not conflict. While this port is subject
* to the GPL I also place my modifications under the original
* license in recognition of the original copyright.
* -- Alan Cox.
*
* Ported from BSD to Linux,
* Alan Cox 22/Nov/1994.
* Zeroing /proc and other additions
* Jos Vos 4/Feb/1995.
* Merged and included the FreeBSD-Current changes at Ugen's request
* (but hey it's a lot cleaner now). Ugen would prefer in some ways
* we waited for his final product but since Linux 1.2.0 is about to
* appear it's not practical - Read: It works, it's not clean but please
* don't consider it to be his standard of finished work.
* Alan Cox 12/Feb/1995
* Porting bidirectional entries from BSD, fixing accounting issues,
* adding struct ip_fwpkt for checking packets with interface address
* Jos Vos 5/Mar/1995.
* Established connections (ACK check), ACK check on bidirectional rules,
* ICMP type check.
* Wilfred Mollenvanger 7/7/1995.
* TCP attack protection.
* Alan Cox 25/8/95, based on information from bugtraq.
* ICMP type printk, IP_FW_F_APPEND
* Bernd Eckenfels 1996-01-31
* Split blocking chain into input and output chains, add new "insert" and
* "append" commands to replace semi-intelligent "add" command, let "delete".
* only delete the first matching entry, use 0xFFFF (0xFF) as ports (ICMP
* types) when counting packets being 2nd and further fragments.
* Jos Vos <jos@xos.nl> 8/2/1996.
* Add support for matching on device names.
* Jos Vos <jos@xos.nl> 15/2/1996.
* Transparent proxying support.
* Willy Konynenberg <willy@xos.nl> 10/5/96.
* Make separate accounting on incoming and outgoing packets possible.
* Jos Vos <jos@xos.nl> 18/5/1996.
* Add timeout reprieve for idle control channels.
* Keith Owens <kaos@audio.apana.org.au> 05/07/1996.
*
*
* Masquerading functionality
*
* Copyright (c) 1994 Pauline Middelink
*
* The pieces which added masquerading functionality are totally
* my responsibility and have nothing to with the original authors
* copyright or doing.
*
* Parts distributed under GPL.
*
* Fixes:
* Pauline Middelink : Added masquerading.
* Alan Cox : Fixed an error in the merge.
* Thomas Quinot : Fixed port spoofing.
* Alan Cox : Cleaned up retransmits in spoofing.
* Alan Cox : Cleaned up length setting.
* Wouter Gadeyne : Fixed masquerading support of ftp PORT commands
*
* Juan Jose Ciarlante : Masquerading code moved to ip_masq.c
*
* All the real work was done by .....
*
*/
/*
* 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.
*/
#include <linux/config.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/config.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/icmp.h>
#include <linux/udp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/sock.h>
#include <net/icmp.h>
#include <linux/firewall.h>
#include <linux/ip_fw.h>
#ifdef CONFIG_IP_MASQUERADE
#include <net/ip_masq.h>
#endif
#include <net/checksum.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
/*
* Implement IP packet firewall
*/
#ifdef DEBUG_IP_FIREWALL
#define dprintf1(a) printk(a)
#define dprintf2(a1,a2) printk(a1,a2)
#define dprintf3(a1,a2,a3) printk(a1,a2,a3)
#define dprintf4(a1,a2,a3,a4) printk(a1,a2,a3,a4)
#else
#define dprintf1(a)
#define dprintf2(a1,a2)
#define dprintf3(a1,a2,a3)
#define dprintf4(a1,a2,a3,a4)
#endif
#define print_ip(a) printk("%ld.%ld.%ld.%ld",(ntohl(a)>>24)&0xFF,\
(ntohl(a)>>16)&0xFF,\
(ntohl(a)>>8)&0xFF,\
(ntohl(a))&0xFF);
#ifdef DEBUG_IP_FIREWALL
#define dprint_ip(a) print_ip(a)
#else
#define dprint_ip(a)
#endif
#if defined(CONFIG_IP_ACCT) || defined(CONFIG_IP_FIREWALL)
struct ip_fw *ip_fw_fwd_chain;
struct ip_fw *ip_fw_in_chain;
struct ip_fw *ip_fw_out_chain;
struct ip_fw *ip_acct_chain;
static struct ip_fw **chains[] =
{&ip_fw_fwd_chain, &ip_fw_in_chain, &ip_fw_out_chain, &ip_acct_chain};
int ip_fw_fwd_policy=IP_FW_F_ACCEPT;
int ip_fw_in_policy=IP_FW_F_ACCEPT;
int ip_fw_out_policy=IP_FW_F_ACCEPT;
static int *policies[] =
{&ip_fw_fwd_policy, &ip_fw_in_policy, &ip_fw_out_policy};
#endif
/*
* Returns 1 if the port is matched by the vector, 0 otherwise
*/
extern inline int port_match(unsigned short *portptr,int nports,unsigned short port,int range_flag)
{
if (!nports)
return 1;
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);
}
#if defined(CONFIG_IP_ACCT) || defined(CONFIG_IP_FIREWALL)
/*
* Returns one of the generic firewall policies, like FW_ACCEPT.
* Also does accounting so you can feed it the accounting chain.
*
* The modes is either IP_FW_MODE_FW (normal firewall mode),
* IP_FW_MODE_ACCT_IN or IP_FW_MODE_ACCT_OUT (accounting mode,
* steps through the entire chain and handles fragments
* differently), or IP_FW_MODE_CHK (handles user-level check,
* counters are not updated).
*/
int ip_fw_chk(struct iphdr *ip, struct device *rif, __u16 *redirport, struct ip_fw *chain, int policy, int mode)
{
struct ip_fw *f;
struct tcphdr *tcp=(struct tcphdr *)((__u32 *)ip+ip->ihl);
struct udphdr *udp=(struct udphdr *)((__u32 *)ip+ip->ihl);
struct icmphdr *icmp=(struct icmphdr *)((__u32 *)ip+ip->ihl);
__u32 src, dst;
__u16 src_port=0xFFFF, dst_port=0xFFFF, icmp_type=0xFF;
unsigned short f_prt=0, prt;
char notcpsyn=0, notcpack=0, match;
unsigned short offset;
int answer;
unsigned char tosand, tosxor;
/*
* If the chain is empty follow policy. The BSD one
* accepts anything giving you a time window while
* flushing and rebuilding the tables.
*/
src = ip->saddr;
dst = ip->daddr;
/*
* This way we handle fragmented packets.
* we ignore all fragments but the first one
* so the whole packet can't be reassembled.
* This way we relay on the full info which
* stored only in first packet.
*
* Note that this theoretically allows partial packet
* spoofing. Not very dangerous but paranoid people may
* wish to play with this. It also allows the so called
* "fragment bomb" denial of service attack on some types
* of system.
*/
offset = ntohs(ip->frag_off) & IP_OFFSET;
/*
* Don't allow a fragment of TCP 8 bytes in. Nobody
* normal causes this. Its a cracker trying to break
* in by doing a flag overwrite to pass the direction
* checks.
*/
if (offset == 1 && ip->protocol == IPPROTO_TCP)
return FW_BLOCK;
if (offset!=0 && !(mode & (IP_FW_MODE_ACCT_IN|IP_FW_MODE_ACCT_OUT)) &&
(ip->protocol == IPPROTO_TCP || ip->protocol == IPPROTO_UDP ||
ip->protocol == IPPROTO_ICMP))
return FW_ACCEPT;
/*
* Header fragment for TCP is too small to check the bits.
*/
if(ip->protocol==IPPROTO_TCP && (ip->ihl<<2)+16 > ntohs(ip->tot_len))
return FW_BLOCK;
/*
* Too short.
*
* But only too short for a packet with ports...
*/
else if((ntohs(ip->tot_len)<8+(ip->ihl<<2))&&(ip->protocol==IPPROTO_TCP || ip->protocol==IPPROTO_UDP))
return FW_BLOCK;
src = ip->saddr;
dst = ip->daddr;
/*
* If we got interface from which packet came
* we can use the address directly. This is unlike
* 4.4BSD derived systems that have an address chain
* per device. We have a device per address with dummy
* devices instead.
*/
dprintf1("Packet ");
switch(ip->protocol)
{
case IPPROTO_TCP:
dprintf1("TCP ");
/* ports stay 0xFFFF if it is not the first fragment */
if (!offset) {
src_port=ntohs(tcp->source);
dst_port=ntohs(tcp->dest);
if(!tcp->ack && !tcp->rst)
/* We do NOT have ACK, value TRUE */
notcpack=1;
if(!tcp->syn || !notcpack)
/* We do NOT have SYN, value TRUE */
notcpsyn=1;
}
prt=IP_FW_F_TCP;
break;
case IPPROTO_UDP:
dprintf1("UDP ");
/* ports stay 0xFFFF if it is not the first fragment */
if (!offset) {
src_port=ntohs(udp->source);
dst_port=ntohs(udp->dest);
}
prt=IP_FW_F_UDP;
break;
case IPPROTO_ICMP:
/* icmp_type stays 255 if it is not the first fragment */
if (!offset)
icmp_type=(__u16)(icmp->type);
dprintf2("ICMP:%d ",icmp_type);
prt=IP_FW_F_ICMP;
break;
default:
dprintf2("p=%d ",ip->protocol);
prt=IP_FW_F_ALL;
break;
}
#ifdef DEBUG_IP_FIREWALL
dprint_ip(ip->saddr);
if (ip->protocol==IPPROTO_TCP || ip->protocol==IPPROTO_UDP)
/* This will print 65535 when it is not the first fragment! */
dprintf2(":%d ", src_port);
dprint_ip(ip->daddr);
if (ip->protocol==IPPROTO_TCP || ip->protocol==IPPROTO_UDP)
/* This will print 65535 when it is not the first fragment! */
dprintf2(":%d ",dst_port);
dprintf1("\n");
#endif
for (f=chain;f;f=f->fw_next)
{
/*
* This is a bit simpler as we don't have to walk
* an interface chain as you do in BSD - same logic
* however.
*/
/*
* Match can become 0x01 (a "normal" match was found),
* 0x02 (a reverse match was found), and 0x03 (the
* IP addresses match in both directions).
* Now we know in which direction(s) we should look
* for a match for the TCP/UDP ports. Both directions
* might match (e.g., when both addresses are on the
* same network for which an address/mask is given), but
* the ports might only match in one direction.
* This was obviously wrong in the original BSD code.
*/
match = 0x00;
if ((src&f->fw_smsk.s_addr)==f->fw_src.s_addr
&& (dst&f->fw_dmsk.s_addr)==f->fw_dst.s_addr)
/* normal direction */
match |= 0x01;
if ((f->fw_flg & IP_FW_F_BIDIR) &&
(dst&f->fw_smsk.s_addr)==f->fw_src.s_addr
&& (src&f->fw_dmsk.s_addr)==f->fw_dst.s_addr)
/* reverse direction */
match |= 0x02;
if (!match)
continue;
/*
* Look for a VIA address match
*/
if(f->fw_via.s_addr && rif)
{
if(rif->pa_addr!=f->fw_via.s_addr)
continue; /* Mismatch */
}
/*
* Look for a VIA device match
*/
if(f->fw_viadev)
{
if(rif!=f->fw_viadev)
continue; /* Mismatch */
}
/*
* Ok the chain addresses match.
*/
#ifdef CONFIG_IP_ACCT
/*
* See if we're in accounting mode and only want to
* count incoming or outgoing packets.
*/
if (mode & (IP_FW_MODE_ACCT_IN|IP_FW_MODE_ACCT_OUT) &&
((mode == IP_FW_MODE_ACCT_IN && f->fw_flg&IP_FW_F_ACCTOUT) ||
(mode == IP_FW_MODE_ACCT_OUT && f->fw_flg&IP_FW_F_ACCTIN)))
continue;
#endif
/*
* For all non-TCP packets and/or non-first fragments,
* notcpsyn and notcpack will always be FALSE,
* so the IP_FW_F_TCPSYN and IP_FW_F_TCPACK flags
* are actually ignored for these packets.
*/
if((f->fw_flg&IP_FW_F_TCPSYN) && notcpsyn)
continue;
if((f->fw_flg&IP_FW_F_TCPACK) && notcpack)
continue;
f_prt=f->fw_flg&IP_FW_F_KIND;
if (f_prt!=IP_FW_F_ALL)
{
/*
* Specific firewall - packet's protocol
* must match firewall's.
*/
if(prt!=f_prt)
continue;
if((prt==IP_FW_F_ICMP &&
! port_match(&f->fw_pts[0], f->fw_nsp,
icmp_type,f->fw_flg&IP_FW_F_SRNG)) ||
!(prt==IP_FW_F_ICMP || ((match & 0x01) &&
port_match(&f->fw_pts[0], f->fw_nsp, src_port,
f->fw_flg&IP_FW_F_SRNG) &&
port_match(&f->fw_pts[f->fw_nsp], f->fw_ndp, dst_port,
f->fw_flg&IP_FW_F_DRNG)) || ((match & 0x02) &&
port_match(&f->fw_pts[0], f->fw_nsp, dst_port,
f->fw_flg&IP_FW_F_SRNG) &&
port_match(&f->fw_pts[f->fw_nsp], f->fw_ndp, src_port,
f->fw_flg&IP_FW_F_DRNG))))
{
continue;
}
}
#ifdef CONFIG_IP_FIREWALL_VERBOSE
/*
* VERY ugly piece of code which actually
* makes kernel printf for matching packets...
*/
if (f->fw_flg & IP_FW_F_PRN)
{
__u32 *opt = (__u32 *) (ip + 1);
int opti;
if(mode == IP_FW_MODE_ACCT_IN)
printk(KERN_INFO "IP acct in ");
else if(mode == IP_FW_MODE_ACCT_OUT)
printk(KERN_INFO "IP acct out ");
else {
if(chain == ip_fw_fwd_chain)
printk(KERN_INFO "IP fw-fwd ");
else if(chain == ip_fw_in_chain)
printk(KERN_INFO "IP fw-in ");
else
printk(KERN_INFO "IP fw-out ");
if(f->fw_flg&IP_FW_F_ACCEPT) {
if(f->fw_flg&IP_FW_F_REDIR)
printk("acc/r%d ", f->fw_pts[f->fw_nsp+f->fw_ndp]);
else if(f->fw_flg&IP_FW_F_MASQ)
printk("acc/masq ");
else
printk("acc ");
} else if(f->fw_flg&IP_FW_F_ICMPRPL)
printk("rej ");
else
printk("deny ");
}
printk(rif ? rif->name : "-");
switch(ip->protocol)
{
case IPPROTO_TCP:
printk(" TCP ");
break;
case IPPROTO_UDP:
printk(" UDP ");
break;
case IPPROTO_ICMP:
printk(" ICMP/%d ", icmp_type);
break;
default:
printk(" PROTO=%d ", ip->protocol);
break;
}
print_ip(ip->saddr);
if(ip->protocol == IPPROTO_TCP || ip->protocol == IPPROTO_UDP)
printk(":%hu", src_port);
printk(" ");
print_ip(ip->daddr);
if(ip->protocol == IPPROTO_TCP || ip->protocol == IPPROTO_UDP)
printk(":%hu", dst_port);
printk(" L=%hu S=0x%2.2hX I=%hu F=0x%4.4hX T=%hu",
ntohs(ip->tot_len), ip->tos, ntohs(ip->id),
ip->frag_off, ip->ttl);
for (opti = 0; opti < (ip->ihl - sizeof(struct iphdr) / 4); opti++)
printk(" O=0x%8.8X", *opt++);
printk("\n");
}
#endif
if (mode != IP_FW_MODE_CHK) {
f->fw_bcnt+=ntohs(ip->tot_len);
f->fw_pcnt++;
}
if (!(mode & (IP_FW_MODE_ACCT_IN|IP_FW_MODE_ACCT_OUT)))
break;
} /* Loop */
if (!(mode & (IP_FW_MODE_ACCT_IN|IP_FW_MODE_ACCT_OUT))) {
/*
* We rely on policy defined in the rejecting entry or, if no match
* was found, we rely on the general policy variable for this type
* of firewall.
*/
if (f!=NULL) {
policy=f->fw_flg;
tosand=f->fw_tosand;
tosxor=f->fw_tosxor;
} else {
tosand=0xFF;
tosxor=0x00;
}
if (policy&IP_FW_F_ACCEPT) {
/* Adjust priority and recompute checksum */
__u8 old_tos = ip->tos;
ip->tos = (old_tos & tosand) ^ tosxor;
if (ip->tos != old_tos)
ip_send_check(ip);
#ifdef CONFIG_IP_TRANSPARENT_PROXY
if (policy&IP_FW_F_REDIR) {
if (redirport)
if ((*redirport = htons(f->fw_pts[f->fw_nsp+f->fw_ndp])) == 0) {
/* Wildcard redirection.
* Note that redirport will become
* 0xFFFF for non-TCP/UDP packets.
*/
*redirport = htons(dst_port);
}
answer = FW_REDIRECT;
} else
#endif
#ifdef CONFIG_IP_MASQUERADE
if (policy&IP_FW_F_MASQ)
answer = FW_MASQUERADE;
else
#endif
answer = FW_ACCEPT;
} else if(policy&IP_FW_F_ICMPRPL)
answer = FW_REJECT;
else
answer = FW_BLOCK;
return answer;
} else
/* we're doing accounting, always ok */
return 0;
}
static void zero_fw_chain(struct ip_fw *chainptr)
{
struct ip_fw *ctmp=chainptr;
while(ctmp)
{
ctmp->fw_pcnt=0L;
ctmp->fw_bcnt=0L;
ctmp=ctmp->fw_next;
}
}
static void free_fw_chain(struct ip_fw *volatile* chainptr)
{
unsigned long flags;
save_flags(flags);
cli();
while ( *chainptr != NULL )
{
struct ip_fw *ftmp;
ftmp = *chainptr;
*chainptr = ftmp->fw_next;
kfree_s(ftmp,sizeof(*ftmp));
}
restore_flags(flags);
}
/* Volatiles to keep some of the compiler versions amused */
static int insert_in_chain(struct ip_fw *volatile* chainptr, struct ip_fw *frwl,int len)
{
struct ip_fw *ftmp;
unsigned long flags;
save_flags(flags);
ftmp = kmalloc( sizeof(struct ip_fw), GFP_ATOMIC );
if ( ftmp == NULL )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: malloc said no\n");
#endif
return( ENOMEM );
}
memcpy(ftmp, frwl, len);
/*
* Allow the more recent "minimise cost" flag to be
* set. [Rob van Nieuwkerk]
*/
ftmp->fw_tosand |= 0x01;
ftmp->fw_tosxor &= 0xFE;
ftmp->fw_pcnt=0L;
ftmp->fw_bcnt=0L;
cli();
if ((ftmp->fw_vianame)[0]) {
if (!(ftmp->fw_viadev = dev_get(ftmp->fw_vianame)))
ftmp->fw_viadev = (struct device *) -1;
} else
ftmp->fw_viadev = NULL;
ftmp->fw_next = *chainptr;
*chainptr=ftmp;
restore_flags(flags);
return(0);
}
static int append_to_chain(struct ip_fw *volatile* chainptr, struct ip_fw *frwl,int len)
{
struct ip_fw *ftmp;
struct ip_fw *chtmp=NULL;
struct ip_fw *volatile chtmp_prev=NULL;
unsigned long flags;
save_flags(flags);
ftmp = kmalloc( sizeof(struct ip_fw), GFP_ATOMIC );
if ( ftmp == NULL )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: malloc said no\n");
#endif
return( ENOMEM );
}
memcpy(ftmp, frwl, len);
/*
* Allow the more recent "minimise cost" flag to be
* set. [Rob van Nieuwkerk]
*/
ftmp->fw_tosand |= 0x01;
ftmp->fw_tosxor &= 0xFE;
ftmp->fw_pcnt=0L;
ftmp->fw_bcnt=0L;
ftmp->fw_next = NULL;
cli();
if ((ftmp->fw_vianame)[0]) {
if (!(ftmp->fw_viadev = dev_get(ftmp->fw_vianame)))
ftmp->fw_viadev = (struct device *) -1;
} else
ftmp->fw_viadev = NULL;
chtmp_prev=NULL;
for (chtmp=*chainptr;chtmp!=NULL;chtmp=chtmp->fw_next)
chtmp_prev=chtmp;
if (chtmp_prev)
chtmp_prev->fw_next=ftmp;
else
*chainptr=ftmp;
restore_flags(flags);
return(0);
}
static int del_from_chain(struct ip_fw *volatile*chainptr, struct ip_fw *frwl)
{
struct ip_fw *ftmp,*ltmp;
unsigned short tport1,tport2,tmpnum;
char matches,was_found;
unsigned long flags;
save_flags(flags);
cli();
ftmp=*chainptr;
if ( ftmp == NULL )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: chain is empty\n");
#endif
restore_flags(flags);
return( EINVAL );
}
ltmp=NULL;
was_found=0;
while( !was_found && ftmp != NULL )
{
matches=1;
if (ftmp->fw_src.s_addr!=frwl->fw_src.s_addr
|| ftmp->fw_dst.s_addr!=frwl->fw_dst.s_addr
|| ftmp->fw_smsk.s_addr!=frwl->fw_smsk.s_addr
|| ftmp->fw_dmsk.s_addr!=frwl->fw_dmsk.s_addr
|| ftmp->fw_via.s_addr!=frwl->fw_via.s_addr
|| ftmp->fw_flg!=frwl->fw_flg)
matches=0;
tport1=ftmp->fw_nsp+ftmp->fw_ndp;
tport2=frwl->fw_nsp+frwl->fw_ndp;
if (tport1!=tport2)
matches=0;
else if (tport1!=0)
{
for (tmpnum=0;tmpnum < tport1 && tmpnum < IP_FW_MAX_PORTS;tmpnum++)
if (ftmp->fw_pts[tmpnum]!=frwl->fw_pts[tmpnum])
matches=0;
}
if (strncmp(ftmp->fw_vianame, frwl->fw_vianame, IFNAMSIZ))
matches=0;
if(matches)
{
was_found=1;
if (ltmp)
{
ltmp->fw_next=ftmp->fw_next;
kfree_s(ftmp,sizeof(*ftmp));
ftmp=ltmp->fw_next;
}
else
{
*chainptr=ftmp->fw_next;
kfree_s(ftmp,sizeof(*ftmp));
ftmp=*chainptr;
}
}
else
{
ltmp = ftmp;
ftmp = ftmp->fw_next;
}
}
restore_flags(flags);
if (was_found)
return 0;
else
return(EINVAL);
}
#endif /* CONFIG_IP_ACCT || CONFIG_IP_FIREWALL */
struct ip_fw *check_ipfw_struct(struct ip_fw *frwl, int len)
{
if ( len != sizeof(struct ip_fw) )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: len=%d, want %d\n",len, sizeof(struct ip_fw));
#endif
return(NULL);
}
if ( (frwl->fw_flg & ~IP_FW_F_MASK) != 0 )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: undefined flag bits set (flags=%x)\n",
frwl->fw_flg);
#endif
return(NULL);
}
#ifndef CONFIG_IP_TRANSPARENT_PROXY
if (frwl->fw_flg & IP_FW_F_REDIR) {
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: unsupported flag IP_FW_F_REDIR\n");
#endif
return(NULL);
}
#endif
#ifndef CONFIG_IP_MASQUERADE
if (frwl->fw_flg & IP_FW_F_MASQ) {
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: unsupported flag IP_FW_F_MASQ\n");
#endif
return(NULL);
}
#endif
if ( (frwl->fw_flg & IP_FW_F_SRNG) && frwl->fw_nsp < 2 )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: src range set but fw_nsp=%d\n",
frwl->fw_nsp);
#endif
return(NULL);
}
if ( (frwl->fw_flg & IP_FW_F_DRNG) && frwl->fw_ndp < 2 )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: dst range set but fw_ndp=%d\n",
frwl->fw_ndp);
#endif
return(NULL);
}
if ( frwl->fw_nsp + frwl->fw_ndp > (frwl->fw_flg & IP_FW_F_REDIR ? IP_FW_MAX_PORTS - 1 : IP_FW_MAX_PORTS) )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: too many ports (%d+%d)\n",
frwl->fw_nsp,frwl->fw_ndp);
#endif
return(NULL);
}
return frwl;
}
#ifdef CONFIG_IP_ACCT
int ip_acct_ctl(int stage, void *m, int len)
{
if ( stage == IP_ACCT_FLUSH )
{
free_fw_chain(&ip_acct_chain);
return(0);
}
if ( stage == IP_ACCT_ZERO )
{
zero_fw_chain(ip_acct_chain);
return(0);
}
if ( stage == IP_ACCT_INSERT || stage == IP_ACCT_APPEND ||
stage == IP_ACCT_DELETE )
{
struct ip_fw *frwl;
if (!(frwl=check_ipfw_struct(m,len)))
return (EINVAL);
switch (stage)
{
case IP_ACCT_INSERT:
return( insert_in_chain(&ip_acct_chain,frwl,len));
case IP_ACCT_APPEND:
return( append_to_chain(&ip_acct_chain,frwl,len));
case IP_ACCT_DELETE:
return( del_from_chain(&ip_acct_chain,frwl));
default:
/*
* Should be panic but... (Why ??? - AC)
*/
#ifdef DEBUG_IP_FIREWALL
printk("ip_acct_ctl: unknown request %d\n",stage);
#endif
return(EINVAL);
}
}
#ifdef DEBUG_IP_FIREWALL
printk("ip_acct_ctl: unknown request %d\n",stage);
#endif
return(EINVAL);
}
#endif
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
int ip_autofw_add(struct ip_autofw * af)
{
struct ip_autofw * newaf;
init_timer(&af->timer);
newaf = kmalloc( sizeof(struct ip_autofw), GFP_ATOMIC );
if ( newaf == NULL )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_autofw_add: malloc said no\n");
#endif
return( ENOMEM );
}
memcpy(newaf, af, sizeof(struct ip_autofw));
newaf->timer.data = (unsigned long) newaf;
newaf->timer.function = ip_autofw_expire;
newaf->timer.expires = 0;
newaf->lastcontact=0;
newaf->next=ip_autofw_hosts;
ip_autofw_hosts=newaf;
return(0);
}
int ip_autofw_del(struct ip_autofw * af)
{
struct ip_autofw * prev, * curr;
prev=NULL;
curr=ip_autofw_hosts;
while (curr)
{
if (af->type == curr->type &&
af->low == curr->low &&
af->high == curr->high &&
af->hidden == curr->hidden &&
af->visible == curr->visible &&
af->protocol == curr->protocol &&
af->where == curr->where &&
af->ctlproto == curr->ctlproto &&
af->ctlport == curr->ctlport)
{
if (prev)
{
prev->next=curr->next;
kfree_s(curr,sizeof(struct ip_autofw));
return(0);
}
else
{
kfree_s(ip_autofw_hosts,sizeof(struct ip_autofw));
ip_autofw_hosts=curr->next;
return(0);
}
}
prev=curr;
curr=curr->next;
}
return(EINVAL);
}
int ip_autofw_flush(void)
{
struct ip_autofw * af;
while (ip_autofw_hosts)
{
af=ip_autofw_hosts;
ip_autofw_hosts=ip_autofw_hosts->next;
kfree_s(af,sizeof(struct ip_autofw));
}
return(0);
}
int ip_autofw_ctl(int stage, void *m, int len)
{
if (stage == IP_AUTOFW_ADD)
return (ip_autofw_add((struct ip_autofw *) m));
if (stage == IP_AUTOFW_DEL)
return (ip_autofw_del((struct ip_autofw *) m));
if (stage == IP_AUTOFW_FLUSH)
return (ip_autofw_flush());
return(EINVAL);
}
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
#ifdef CONFIG_IP_FIREWALL
int ip_fw_ctl(int stage, void *m, int len)
{
int cmd, fwtype;
cmd = stage & IP_FW_COMMAND;
fwtype = (stage & IP_FW_TYPE) >> IP_FW_SHIFT;
if ( cmd == IP_FW_FLUSH )
{
free_fw_chain(chains[fwtype]);
return(0);
}
if ( cmd == IP_FW_ZERO )
{
zero_fw_chain(*chains[fwtype]);
return(0);
}
if ( cmd == IP_FW_POLICY )
{
int *tmp_policy_ptr;
tmp_policy_ptr=(int *)m;
*policies[fwtype] = *tmp_policy_ptr;
return 0;
}
if ( cmd == IP_FW_CHECK )
{
struct device *viadev;
struct ip_fwpkt *ipfwp;
struct iphdr *ip;
if ( len != sizeof(struct ip_fwpkt) )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: length=%d, expected %d\n",
len, sizeof(struct ip_fwpkt));
#endif
return( EINVAL );
}
ipfwp = (struct ip_fwpkt *)m;
ip = &(ipfwp->fwp_iph);
if ( !(viadev = dev_get(ipfwp->fwp_vianame)) ) {
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: invalid device \"%s\"\n", ipfwp->fwp_vianame);
#endif
return(EINVAL);
} else if ( viadev->pa_addr != ipfwp->fwp_via.s_addr ) {
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: device \"%s\" has another IP address\n",
ipfwp->fwp_vianame);
#endif
return(EINVAL);
} else if ( ip->ihl != sizeof(struct iphdr) / sizeof(int)) {
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: ip->ihl=%d, want %d\n",ip->ihl,
sizeof(struct iphdr)/sizeof(int));
#endif
return(EINVAL);
}
switch (ip_fw_chk(ip, viadev, NULL, *chains[fwtype],
*policies[fwtype], IP_FW_MODE_CHK))
{
case FW_ACCEPT:
return(0);
case FW_REDIRECT:
return(ECONNABORTED);
case FW_MASQUERADE:
return(ECONNRESET);
case FW_REJECT:
return(ECONNREFUSED);
default: /* FW_BLOCK */
return(ETIMEDOUT);
}
}
if ( cmd == IP_FW_MASQ_TIMEOUTS )
{
#ifdef CONFIG_IP_MASQUERADE
struct ip_fw_masq *masq;
if ( len != sizeof(struct ip_fw_masq) )
{
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl (masq): length %d, expected %d\n",
len, sizeof(struct ip_fw_masq));
#endif
return( EINVAL );
}
masq = (struct ip_fw_masq *) m;
if (masq->tcp_timeout)
{
ip_masq_expire->tcp_timeout = masq->tcp_timeout;
}
if (masq->tcp_fin_timeout)
{
ip_masq_expire->tcp_fin_timeout = masq->tcp_fin_timeout;
}
if (masq->udp_timeout)
{
ip_masq_expire->udp_timeout = masq->udp_timeout;
}
return 0;
#else
return( EINVAL );
#endif
}
/*
* Here we really working hard-adding new elements
* to blocking/forwarding chains or deleting 'em
*/
if ( cmd == IP_FW_INSERT || cmd == IP_FW_APPEND || cmd == IP_FW_DELETE )
{
struct ip_fw *frwl;
int fwtype;
frwl=check_ipfw_struct(m,len);
if (frwl==NULL)
return (EINVAL);
fwtype = (stage & IP_FW_TYPE) >> IP_FW_SHIFT;
switch (cmd)
{
case IP_FW_INSERT:
return(insert_in_chain(chains[fwtype],frwl,len));
case IP_FW_APPEND:
return(append_to_chain(chains[fwtype],frwl,len));
case IP_FW_DELETE:
return(del_from_chain(chains[fwtype],frwl));
default:
/*
* Should be panic but... (Why are BSD people panic obsessed ??)
*/
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: unknown request %d\n",stage);
#endif
return(EINVAL);
}
}
#ifdef DEBUG_IP_FIREWALL
printk("ip_fw_ctl: unknown request %d\n",stage);
#endif
return(EINVAL);
}
#endif /* CONFIG_IP_FIREWALL */
#if defined(CONFIG_IP_FIREWALL) || defined(CONFIG_IP_ACCT)
static int ip_chain_procinfo(int stage, char *buffer, char **start,
off_t offset, int length, int reset)
{
off_t pos=0, begin=0;
struct ip_fw *i;
unsigned long flags;
int len, p;
int last_len = 0;
switch(stage)
{
#ifdef CONFIG_IP_FIREWALL
case IP_FW_IN:
i = ip_fw_in_chain;
len=sprintf(buffer, "IP firewall input rules, default %d\n",
ip_fw_in_policy);
break;
case IP_FW_OUT:
i = ip_fw_out_chain;
len=sprintf(buffer, "IP firewall output rules, default %d\n",
ip_fw_out_policy);
break;
case IP_FW_FWD:
i = ip_fw_fwd_chain;
len=sprintf(buffer, "IP firewall forward rules, default %d\n",
ip_fw_fwd_policy);
break;
#endif
#ifdef CONFIG_IP_ACCT
case IP_FW_ACCT:
i = ip_acct_chain;
len=sprintf(buffer,"IP accounting rules\n");
break;
#endif
default:
/* this should never be reached, but safety first... */
i = NULL;
len=0;
break;
}
save_flags(flags);
cli();
while(i!=NULL)
{
len+=sprintf(buffer+len,"%08lX/%08lX->%08lX/%08lX %.16s %08lX %X ",
ntohl(i->fw_src.s_addr),ntohl(i->fw_smsk.s_addr),
ntohl(i->fw_dst.s_addr),ntohl(i->fw_dmsk.s_addr),
(i->fw_vianame)[0] ? i->fw_vianame : "-",
ntohl(i->fw_via.s_addr),i->fw_flg);
len+=sprintf(buffer+len,"%u %u %-10lu %-10lu",
i->fw_nsp,i->fw_ndp, i->fw_pcnt,i->fw_bcnt);
for (p = 0; p < IP_FW_MAX_PORTS; p++)
len+=sprintf(buffer+len, " %u", i->fw_pts[p]);
len+=sprintf(buffer+len, " A%02X X%02X", i->fw_tosand, i->fw_tosxor);
buffer[len++]='\n';
buffer[len]='\0';
pos=begin+len;
if(pos<offset)
{
len=0;
begin=pos;
}
else if(pos>offset+length)
{
len = last_len;
break;
}
else if(reset)
{
/* This needs to be done at this specific place! */
i->fw_pcnt=0L;
i->fw_bcnt=0L;
}
last_len = len;
i=i->fw_next;
}
restore_flags(flags);
*start=buffer+(offset-begin);
len-=(offset-begin);
if(len>length)
len=length;
return len;
}
#endif
#ifdef CONFIG_IP_ACCT
static int ip_acct_procinfo(char *buffer, char **start, off_t offset,
int length, int reset)
{
return ip_chain_procinfo(IP_FW_ACCT, buffer,start, offset,length,
reset);
}
#endif
#ifdef CONFIG_IP_FIREWALL
static int ip_fw_in_procinfo(char *buffer, char **start, off_t offset,
int length, int reset)
{
return ip_chain_procinfo(IP_FW_IN, buffer,start,offset,length,
reset);
}
static int ip_fw_out_procinfo(char *buffer, char **start, off_t offset,
int length, int reset)
{
return ip_chain_procinfo(IP_FW_OUT, buffer,start,offset,length,
reset);
}
static int ip_fw_fwd_procinfo(char *buffer, char **start, off_t offset,
int length, int reset)
{
return ip_chain_procinfo(IP_FW_FWD, buffer,start,offset,length,
reset);
}
#endif
#ifdef CONFIG_IP_FIREWALL
/*
* Interface to the generic firewall chains.
*/
int ipfw_input_check(struct firewall_ops *this, int pf, struct device *dev, void *phdr, void *arg)
{
return ip_fw_chk(phdr, dev, arg, ip_fw_in_chain, ip_fw_in_policy, IP_FW_MODE_FW);
}
int ipfw_output_check(struct firewall_ops *this, int pf, struct device *dev, void *phdr, void *arg)
{
return ip_fw_chk(phdr, dev, arg, ip_fw_out_chain, ip_fw_out_policy, IP_FW_MODE_FW);
}
int ipfw_forward_check(struct firewall_ops *this, int pf, struct device *dev, void *phdr, void *arg)
{
return ip_fw_chk(phdr, dev, arg, ip_fw_fwd_chain, ip_fw_fwd_policy, IP_FW_MODE_FW);
}
struct firewall_ops ipfw_ops=
{
NULL,
ipfw_forward_check,
ipfw_input_check,
ipfw_output_check,
PF_INET,
0 /* We don't even allow a fall through so we are last */
};
#endif
#if defined(CONFIG_IP_ACCT) || defined(CONFIG_IP_FIREWALL)
int ipfw_device_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct device *dev=ptr;
char *devname = dev->name;
unsigned long flags;
struct ip_fw *fw;
int chn;
save_flags(flags);
cli();
if (event == NETDEV_UP) {
for (chn = 0; chn < IP_FW_CHAINS; chn++)
for (fw = *chains[chn]; fw; fw = fw->fw_next)
if ((fw->fw_vianame)[0] && !strncmp(devname,
fw->fw_vianame, IFNAMSIZ))
fw->fw_viadev = dev;
} else if (event == NETDEV_DOWN) {
for (chn = 0; chn < IP_FW_CHAINS; chn++)
for (fw = *chains[chn]; fw; fw = fw->fw_next)
/* we could compare just the pointers ... */
if ((fw->fw_vianame)[0] && !strncmp(devname,
fw->fw_vianame, IFNAMSIZ))
fw->fw_viadev = (struct device *) -1;
}
restore_flags(flags);
return NOTIFY_DONE;
}
static struct notifier_block ipfw_dev_notifier={
ipfw_device_event,
NULL,
0
};
#endif
void ip_fw_init(void)
{
#ifdef CONFIG_PROC_FS
#ifdef CONFIG_IP_ACCT
proc_net_register(&(struct proc_dir_entry) {
PROC_NET_IPACCT, 7, "ip_acct",
S_IFREG | S_IRUGO | S_IWUSR, 1, 0, 0,
0, &proc_net_inode_operations,
ip_acct_procinfo
});
#endif
#endif
#ifdef CONFIG_IP_FIREWALL
if(register_firewall(PF_INET,&ipfw_ops)<0)
panic("Unable to register IP firewall.\n");
#ifdef CONFIG_PROC_FS
proc_net_register(&(struct proc_dir_entry) {
PROC_NET_IPFWIN, 8, "ip_input",
S_IFREG | S_IRUGO | S_IWUSR, 1, 0, 0,
0, &proc_net_inode_operations,
ip_fw_in_procinfo
});
proc_net_register(&(struct proc_dir_entry) {
PROC_NET_IPFWOUT, 9, "ip_output",
S_IFREG | S_IRUGO | S_IWUSR, 1, 0, 0,
0, &proc_net_inode_operations,
ip_fw_out_procinfo
});
proc_net_register(&(struct proc_dir_entry) {
PROC_NET_IPFWFWD, 10, "ip_forward",
S_IFREG | S_IRUGO | S_IWUSR, 1, 0, 0,
0, &proc_net_inode_operations,
ip_fw_fwd_procinfo
});
#endif
#endif
#ifdef CONFIG_IP_MASQUERADE
/*
* Initialize masquerading.
*/
ip_masq_init();
#endif
#if defined(CONFIG_IP_ACCT) || defined(CONFIG_IP_FIREWALL)
/* Register for device up/down reports */
register_netdevice_notifier(&ipfw_dev_notifier);
#endif
}
