static void masq_expire(unsigned long data)
{
struct ip_masq *ms = (struct ip_masq *)data, *ms_data;
unsigned long flags;
if (ms->flags & IP_MASQ_F_CONTROL) {
/* a control channel is about to expire */
int idx = 0, reprieve = 0;
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Masquerade control %s %lX:%X about to expire\n",
masq_proto_name(ms->protocol),
ntohl(ms->saddr),ntohs(ms->sport));
#endif
save_flags(flags);
cli();
/*
* If any other masquerade entry claims that the expiring entry
* is its control channel then keep the control entry alive.
* Useful for long running data channels with inactive control
* links which we don't want to lose, e.g. ftp.
* Assumption: loops such as a->b->a or a->a will never occur.
*/
for (idx = 0; idx < IP_MASQ_TAB_SIZE && !reprieve; idx++) {
for (ms_data = ip_masq_m_tab[idx]; ms_data ; ms_data = ms_data->m_link) {
if (ms_data->control == ms) {
reprieve = 1; /* this control connection can live a bit longer */
ip_masq_set_expire(ms, ip_masq_expire->tcp_timeout);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Masquerade control %s %lX:%X expiry reprieved\n",
masq_proto_name(ms->protocol),
ntohl(ms->saddr),ntohs(ms->sport));
#endif
break;
}
}
}
restore_flags(flags);
if (reprieve)
return;
}
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Masqueraded %s %lX:%X expired\n",masq_proto_name(ms->protocol),ntohl(ms->saddr),ntohs(ms->sport));
#endif
save_flags(flags);
cli();
if (ip_masq_unhash(ms)) {
ip_masq_free_ports[masq_proto_num(ms->protocol)]++;
if (ms->protocol != IPPROTO_ICMP)
ip_masq_unbind_app(ms);
kfree_s(ms,sizeof(*ms));
}
restore_flags(flags);
}
int
masq_irc_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb;
struct iphdr *iph;
struct tcphdr *th;
char *data, *data_limit;
__u32 s_addr;
__u16 s_port;
struct ip_masq *n_ms;
char buf[20]; /* "m_addr m_port" (dec base)*/
unsigned buf_len;
int diff;
int xtra_args = 0; /* extra int args wanted after addr */
char *dcc_p, *addr_beg_p, *addr_end_p;
skb = *skb_p;
iph = skb->h.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
/*
* Hunt irc DCC string, the _shortest_:
*
* strlen("DCC CHAT chat AAAAAAAA P\x01\n")=26
* strlen("DCC SEND F AAAAAAAA P S\x01\n")=25
* AAAAAAAAA: bound addr (1.0.0.0==16777216, min 8 digits)
* P: bound port (min 1 d )
* F: filename (min 1 d )
* S: size (min 1 d )
* 0x01, \n: terminators
*/
data_limit = skb->h.raw + skb->len;
while (data < (data_limit - 25) )
{
if (memcmp(data,"DCC ",4)) {
data ++;
continue;
}
dcc_p = data;
data += 4; /* point to DCC cmd */
if (memcmp(data, "CHAT ", 5) == 0 ||
memcmp(data, "SEND ", 5) == 0)
{
/*
* extra arg (file_size) req. for "SEND"
*/
if (*data == 'S') xtra_args++;
data += 5;
}
else
continue;
/*
* skip next string.
*/
while( *data++ != ' ')
/*
* must still parse, at least, "AAAAAAAA P\x01\n",
* 12 bytes left.
*/
if (data > (data_limit-12)) return 0;
addr_beg_p = data;
/*
* client bound address in dec base
*/
s_addr = simple_strtoul(data,&data,10);
if (*data++ !=' ')
continue;
/*
* client bound port in dec base
*/
s_port = simple_strtoul(data,&data,10);
addr_end_p = data;
/*
* should check args consistency?
*/
while(xtra_args) {
if (*data != ' ')
break;
data++;
simple_strtoul(data,&data,10);
xtra_args--;
}
if (xtra_args != 0) continue;
/*
* terminators.
*/
if (data[0] != 0x01)
continue;
if (data[1]!='\r' && data[1]!='\n')
continue;
/*
* Now create an masquerade entry for it
* must set NO_DPORT and NO_DADDR because
* connection is requested by another client.
*/
n_ms = ip_masq_new(dev, IPPROTO_TCP,
htonl(s_addr),htons(s_port),
0, 0,
IP_MASQ_F_NO_DPORT|IP_MASQ_F_NO_DADDR
);
if (n_ms==NULL)
return 0;
ip_masq_set_expire(n_ms, ip_masq_expire->tcp_fin_timeout);
/*
* Replace the old "address port" with the new one
*/
buf_len = sprintf(buf,"%lu %u",
ntohl(n_ms->maddr),ntohs(n_ms->mport));
/*
* Calculate required delta-offset to keep TCP happy
*/
diff = buf_len - (addr_end_p-addr_beg_p);
#if DEBUG_CONFIG_IP_MASQ_IRC
*addr_beg_p = '\0';
printk("masq_irc_out(): '%s' %X:%X detected (diff=%d)\n", dcc_p, s_addr,s_port, diff);
#endif
/*
* No shift.
*/
if (diff==0)
{
/*
* simple case, just copy.
*/
memcpy(addr_beg_p,buf,buf_len);
return 0;
}
*skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC,
addr_beg_p, addr_end_p-addr_beg_p,
buf, buf_len);
return diff;
}
return 0;
}
int
masq_vdolive_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb;
struct iphdr *iph;
struct tcphdr *th;
char *data, *data_limit;
unsigned int tagval; /* This should be a 32 bit quantity */
struct ip_masq *n_ms;
struct vdolive_priv_data *priv =
(struct vdolive_priv_data *)ms->app_data;
/* This doesn't work at all if no priv data was allocated on startup */
if (!priv)
return 0;
/* Everything running correctly already */
if (priv->state == 3)
return 0;
skb = *skb_p;
iph = skb->h.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
data_limit = skb->h.raw + skb->len;
if (data+8 > data_limit) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: packet too short for ID %lx %lx\n",
data, data_limit);
#endif
return 0;
}
memcpy(&tagval, data+4, 4);
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: packet seen, tag %ld, in initial state %d\n",
ntohl(tagval), priv->state);
#endif
/* Check for leading packet ID */
if ((ntohl(tagval) != 6) && (ntohl(tagval) != 1)) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: unrecognised tag %ld, in initial state %d\n",
ntohl(tagval), priv->state);
#endif
return 0;
}
/* Check packet is long enough for data - ignore if not */
if ((ntohl(tagval) == 6) && (data+36 > data_limit)) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: initial packet too short %lx %lx\n",
data, data_limit);
#endif
return 0;
} else if ((ntohl(tagval) == 1) && (data+20 > data_limit)) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: secondary packet too short %lx %lx\n",
data, data_limit);
#endif
return 0;
}
/* Adjust data pointers */
/*
* I could check the complete protocol version tag
* in here however I am just going to look for the
* "VDO Live" tag in the hope that this part will
* remain constant even if the version changes
*/
if (ntohl(tagval) == 6) {
data += 24;
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: initial packet found\n");
#endif
} else {
data += 8;
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: secondary packet found\n");
#endif
}
if (memcmp(data, "VDO Live", 8) != 0) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: did not find tag\n");
#endif
return 0;
}
/*
* The port number is the next word after the tag.
* VDOlive encodes all of these values
* in 32 bit words, so in this case I am
* skipping the first 2 bytes of the next
* word to get to the relevant 16 bits
*/
data += 10;
/*
* If we have not seen the port already,
* set the masquerading tunnel up
*/
if (!priv->origport) {
memcpy(&priv->origport, data, 2);
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: found port %d\n",
ntohs(priv->origport));
#endif
/* Open up a tunnel */
n_ms = ip_masq_new(dev, IPPROTO_UDP,
ms->saddr, priv->origport,
ms->daddr, 0,
IP_MASQ_F_NO_DPORT);
if (n_ms==NULL) {
printk("VDOlive: unable to build UDP tunnel for %x:%x\n",
ms->saddr, priv->origport);
/* Leave state as unset */
priv->origport = 0;
return 0;
}
ip_masq_set_expire(n_ms, ip_masq_expire->udp_timeout);
priv->masqport = n_ms->mport;
} else if (memcmp(data, &(priv->origport), 2)) {
printk("VDOlive: ports do not match\n");
/* Write the port in anyhow!!! */
}
/*
* Write masq port into packet
*/
memcpy(data, &(priv->masqport), 2);
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: rewrote port %d to %d, server %s\n",
ntohs(priv->origport), ntohs(priv->masqport), in_ntoa(ms->saddr));
#endif
/*
* Set state bit to make which bit has been done
*/
priv->state |= (ntohl(tagval) == 6) ? 1 : 2;
return 0;
}
int ip_fw_masq_icmp(struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb = *skb_p;
struct iphdr *iph = skb->h.iph;
struct icmphdr *icmph = (struct icmphdr *)((char *)iph + (iph->ihl<<2));
struct iphdr *ciph; /* The ip header contained within the ICMP */
__u16 *pptr; /* port numbers from TCP/UDP contained header */
struct ip_masq *ms;
unsigned short len = ntohs(iph->tot_len) - (iph->ihl * 4);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("Incoming forward ICMP (%d,%d) %lX -> %lX\n",
icmph->type, ntohs(icmp_id(icmph)),
ntohl(iph->saddr), ntohl(iph->daddr));
#endif
#ifdef CONFIG_IP_MASQUERADE_ICMP
if ((icmph->type == ICMP_ECHO ) ||
(icmph->type == ICMP_TIMESTAMP ) ||
(icmph->type == ICMP_INFO_REQUEST ) ||
(icmph->type == ICMP_ADDRESS )) {
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: icmp request rcv %lX->%lX id %d type %d\n",
ntohl(iph->saddr),
ntohl(iph->daddr),
ntohs(icmp_id(icmph)),
icmph->type);
#endif
ms = ip_masq_out_get_2(iph->protocol,
iph->saddr,
icmp_id(icmph),
iph->daddr,
icmp_hv_req(icmph));
if (ms == NULL) {
ms = ip_masq_new(dev,
iph->protocol,
iph->saddr,
icmp_id(icmph),
iph->daddr,
icmp_hv_req(icmph),
0);
if (ms == NULL)
return (-1);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: Create new icmp entry\n");
#endif
}
ip_masq_set_expire(ms, 0);
/* Rewrite source address */
/*
* If sysctl !=0 and no pkt has been received yet
* in this tunnel and routing iface address has changed...
* "You are welcome, diald".
*/
if ( sysctl_ip_dynaddr && ms->flags & IP_MASQ_F_NO_REPLY && dev->pa_addr != ms->maddr) {
unsigned long flags;
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk(KERN_INFO "ip_fw_masq_icmp(): change masq.addr %s",
in_ntoa(ms->maddr));
printk("-> %s\n", in_ntoa(dev->pa_addr));
#endif
save_flags(flags);
cli();
ip_masq_unhash(ms);
ms->maddr = dev->pa_addr;
ip_masq_hash(ms);
restore_flags(flags);
}
iph->saddr = ms->maddr;
ip_send_check(iph);
/* Rewrite port (id) */
(icmph->un).echo.id = ms->mport;
icmph->checksum = 0;
icmph->checksum = ip_compute_csum((unsigned char *)icmph, len);
ip_masq_set_expire(ms, MASQUERADE_EXPIRE_ICMP);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: icmp request rwt %lX->%lX id %d type %d\n",
ntohl(iph->saddr),
ntohl(iph->daddr),
ntohs(icmp_id(icmph)),
icmph->type);
#endif
return (1);
}
#endif
/*
* Work through seeing if this is for us.
* These checks are supposed to be in an order that
* means easy things are checked first to speed up
* processing.... however this means that some
* packets will manage to get a long way down this
* stack and then be rejected, but thats life
*/
if ((icmph->type != ICMP_DEST_UNREACH) &&
(icmph->type != ICMP_SOURCE_QUENCH) &&
(icmph->type != ICMP_TIME_EXCEEDED))
return 0;
/* Now find the contained IP header */
ciph = (struct iphdr *) (icmph + 1);
#ifdef CONFIG_IP_MASQUERADE_ICMP
if (ciph->protocol == IPPROTO_ICMP) {
/*
* This section handles ICMP errors for ICMP packets
*/
struct icmphdr *cicmph = (struct icmphdr *)((char *)ciph +
(ciph->ihl<<2));
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: fw icmp/icmp rcv %lX->%lX id %d type %d\n",
ntohl(ciph->saddr),
ntohl(ciph->daddr),
ntohs(icmp_id(cicmph)),
cicmph->type);
#endif
ms = ip_masq_out_get_2(ciph->protocol,
ciph->daddr,
icmp_id(cicmph),
ciph->saddr,
icmp_hv_rep(cicmph));
if (ms == NULL)
return 0;
/* Now we do real damage to this packet...! */
/* First change the source IP address, and recalc checksum */
iph->saddr = ms->maddr;
ip_send_check(iph);
/* Now change the *dest* address in the contained IP */
ciph->daddr = ms->maddr;
ip_send_check(ciph);
/* Change the ID to the masqed one! */
(cicmph->un).echo.id = ms->mport;
/* And finally the ICMP checksum */
icmph->checksum = 0;
icmph->checksum = ip_compute_csum((unsigned char *) icmph, len);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: fw icmp/icmp rwt %lX->%lX id %d type %d\n",
ntohl(ciph->saddr),
ntohl(ciph->daddr),
ntohs(icmp_id(cicmph)),
cicmph->type);
#endif
return 1;
}
#endif /* CONFIG_IP_MASQUERADE_ICMP */
/* We are only interested ICMPs generated from TCP or UDP packets */
if ((ciph->protocol != IPPROTO_UDP) && (ciph->protocol != IPPROTO_TCP))
return 0;
/*
* Find the ports involved - this packet was
* incoming so the ports are right way round
* (but reversed relative to outer IP header!)
*/
pptr = (__u16 *)&(((char *)ciph)[ciph->ihl*4]);
/* Ensure the checksum is correct */
if (ip_compute_csum((unsigned char *) icmph, len))
{
/* Failed checksum! */
printk(KERN_DEBUG "MASQ: forward ICMP: failed checksum from %s!\n",
in_ntoa(iph->saddr));
return(-1);
}
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Handling forward ICMP for %lX:%X -> %lX:%X\n",
ntohl(ciph->saddr), ntohs(pptr[0]),
ntohl(ciph->daddr), ntohs(pptr[1]));
#endif
/* This is pretty much what ip_masq_out_get() does */
ms = ip_masq_out_get_2(ciph->protocol,
ciph->daddr,
pptr[1],
ciph->saddr,
pptr[0]);
if (ms == NULL)
return 0;
/* Now we do real damage to this packet...! */
/* First change the source IP address, and recalc checksum */
iph->saddr = ms->maddr;
ip_send_check(iph);
/* Now change the *dest* address in the contained IP */
ciph->daddr = ms->maddr;
ip_send_check(ciph);
/* the TCP/UDP dest port - cannot redo check */
pptr[1] = ms->mport;
/* And finally the ICMP checksum */
icmph->checksum = 0;
icmph->checksum = ip_compute_csum((unsigned char *) icmph, len);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Rewrote forward ICMP to %lX:%X -> %lX:%X\n",
ntohl(ciph->saddr), ntohs(pptr[0]),
ntohl(ciph->daddr), ntohs(pptr[1]));
#endif
return 1;
}
int ip_fw_masquerade(struct sk_buff **skb_ptr, struct device *dev)
{
struct sk_buff *skb=*skb_ptr;
struct iphdr *iph = skb->h.iph;
__u16 *portptr;
struct ip_masq *ms;
int size;
unsigned long timeout;
/*
* We can only masquerade protocols with ports...
* [TODO]
* We may need to consider masq-ing some ICMP related to masq-ed protocols
*/
if (iph->protocol==IPPROTO_ICMP)
return (ip_fw_masq_icmp(skb_ptr,dev));
if (iph->protocol!=IPPROTO_UDP && iph->protocol!=IPPROTO_TCP)
return -1;
/*
* Now hunt the list to see if we have an old entry
*/
portptr = (__u16 *)&(((char *)iph)[iph->ihl*4]);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Outgoing %s %lX:%X -> %lX:%X\n",
masq_proto_name(iph->protocol),
ntohl(iph->saddr), ntohs(portptr[0]),
ntohl(iph->daddr), ntohs(portptr[1]));
#endif
ms = ip_masq_out_get(iph);
if (ms!=NULL) {
ip_masq_set_expire(ms,0);
/*
* If sysctl !=0 and no pkt has been received yet
* in this tunnel and routing iface address has changed...
* "You are welcome, diald".
*/
if ( sysctl_ip_dynaddr && ms->flags & IP_MASQ_F_NO_REPLY && dev->pa_addr != ms->maddr) {
unsigned long flags;
if (sysctl_ip_dynaddr > 1) {
printk(KERN_INFO "ip_fw_masquerade(): change maddr from %s",
in_ntoa(ms->maddr));
printk(" to %s\n", in_ntoa(dev->pa_addr));
}
save_flags(flags);
cli();
ip_masq_unhash(ms);
ms->maddr = dev->pa_addr;
ip_masq_hash(ms);
restore_flags(flags);
}
/*
* Set sport if not defined yet (e.g. ftp PASV). Because
* masq entries are hashed on sport, unhash with old value
* and hash with new.
*/
if ( ms->flags & IP_MASQ_F_NO_SPORT && ms->protocol == IPPROTO_TCP ) {
unsigned long flags;
ms->flags &= ~IP_MASQ_F_NO_SPORT;
save_flags(flags);
cli();
ip_masq_unhash(ms);
ms->sport = portptr[0];
ip_masq_hash(ms); /* hash on new sport */
restore_flags(flags);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("ip_fw_masquerade(): filled sport=%d\n",
ntohs(ms->sport));
#endif
}
}
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
/* update any ipautofw entries .. */
ip_autofw_update_out(iph->saddr, iph->daddr, portptr[1],
iph->protocol);
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
/*
* Nope, not found, create a new entry for it
*/
if (ms==NULL)
{
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
/* if the source port is supposed to match the masq port, then
make it so */
if (ip_autofw_check_direct(portptr[1],iph->protocol))
ms = ip_masq_new_enh(dev, iph->protocol,
iph->saddr, portptr[0],
iph->daddr, portptr[1],
0,
portptr[0]);
else
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
ms = ip_masq_new_enh(dev, iph->protocol,
iph->saddr, portptr[0],
iph->daddr, portptr[1],
0,
0);
if (ms == NULL)
return -1;
}
/*
* Change the fragments origin
*/
size = skb->len - ((unsigned char *)portptr - skb->h.raw);
/*
* Set iph addr and port from ip_masq obj.
*/
iph->saddr = ms->maddr;
portptr[0] = ms->mport;
/*
* Attempt ip_masq_app call.
* will fix ip_masq and iph seq stuff
*/
if (ip_masq_app_pkt_out(ms, skb_ptr, dev) != 0)
{
/*
* skb has possibly changed, update pointers.
*/
skb = *skb_ptr;
iph = skb->h.iph;
portptr = (__u16 *)&(((char *)iph)[iph->ihl*4]);
size = skb->len - ((unsigned char *)portptr-skb->h.raw);
}
/*
* Adjust packet accordingly to protocol
*/
if (masq_proto_num(iph->protocol)==0)
{
timeout = ip_masq_expire->udp_timeout;
recalc_check((struct udphdr *)portptr,iph->saddr,iph->daddr,size);
}
else
{
struct tcphdr *th;
th = (struct tcphdr *)portptr;
/* Set the flags up correctly... */
if (th->fin)
{
ms->flags |= IP_MASQ_F_SAW_FIN_OUT;
}
if (th->rst)
{
ms->flags |= IP_MASQ_F_SAW_RST;
}
/*
* Timeout depends if FIN packet has been seen
* Very short timeout if RST packet seen.
*/
if (ms->flags & IP_MASQ_F_SAW_RST)
{
timeout = 1;
}
else if ((ms->flags & IP_MASQ_F_SAW_FIN) == IP_MASQ_F_SAW_FIN)
{
timeout = ip_masq_expire->tcp_fin_timeout;
}
else timeout = ip_masq_expire->tcp_timeout;
skb->csum = csum_partial((void *)(th + 1), size - sizeof(*th), 0);
tcp_send_check(th,iph->saddr,iph->daddr,size,skb);
}
ip_masq_set_expire(ms, timeout);
ip_send_check(iph);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("O-routed from %lX:%X over %s\n",ntohl(ms->maddr),ntohs(ms->mport),dev->name);
#endif
return 0;
}
int ip_fw_demasquerade(struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb = *skb_p;
struct iphdr *iph = skb->h.iph;
__u16 *portptr;
struct ip_masq *ms;
unsigned short len;
unsigned long timeout;
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
struct ip_autofw *af;
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
switch (iph->protocol) {
case IPPROTO_ICMP:
return(ip_fw_demasq_icmp(skb_p, dev));
case IPPROTO_TCP:
case IPPROTO_UDP:
/* Make sure packet is in the masq range */
portptr = (__u16 *)&(((char *)iph)[iph->ihl*4]);
if ((ntohs(portptr[1]) < PORT_MASQ_BEGIN ||
ntohs(portptr[1]) > PORT_MASQ_END)
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
&& !ip_autofw_check_range(iph->saddr, portptr[1],
iph->protocol, 0)
&& !ip_autofw_check_direct(portptr[1], iph->protocol)
&& !ip_autofw_check_port(portptr[1], iph->protocol)
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
)
return 0;
/* Check that the checksum is OK */
len = ntohs(iph->tot_len) - (iph->ihl * 4);
if ((iph->protocol == IPPROTO_UDP) && (portptr[3] == 0))
/* No UDP checksum */
break;
switch (skb->ip_summed)
{
case CHECKSUM_NONE:
skb->csum = csum_partial((char *)portptr, len, 0);
case CHECKSUM_HW:
if (csum_tcpudp_magic(iph->saddr, iph->daddr, len,
iph->protocol, skb->csum))
{
printk(KERN_DEBUG "MASQ: failed TCP/UDP checksum from %s!\n",
in_ntoa(iph->saddr));
return -1;
}
default:
/* CHECKSUM_UNNECESSARY */
}
break;
default:
return 0;
}
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Incoming %s %lX:%X -> %lX:%X\n",
masq_proto_name(iph->protocol),
ntohl(iph->saddr), ntohs(portptr[0]),
ntohl(iph->daddr), ntohs(portptr[1]));
#endif
/*
* reroute to original host:port if found...
*/
ms = ip_masq_in_get(iph);
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
if (ms == NULL && (af=ip_autofw_check_range(iph->saddr, portptr[1], iph->protocol, 0)))
{
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("ip_autofw_check_range\n");
#endif
ms = ip_masq_new_enh(dev, iph->protocol,
af->where, portptr[1],
iph->saddr, portptr[0],
0,
portptr[1]);
}
if ( ms == NULL && (af=ip_autofw_check_port(portptr[1], iph->protocol)) )
{
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("ip_autofw_check_port\n");
#endif
ms = ip_masq_new_enh(dev, iph->protocol,
af->where, htons(af->hidden),
iph->saddr, portptr[0],
IP_MASQ_F_AFW_PORT,
htons(af->visible));
}
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
if (ms != NULL)
{
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
ip_autofw_update_in(iph->saddr, portptr[1], iph->protocol);
#endif /* CONFIG_IP_MASQUERADE_IPAUTOFW */
/* Stop the timer ticking.... */
ip_masq_set_expire(ms,0);
/*
* got reply, so clear flag
*/
ms->flags &= ~IP_MASQ_F_NO_REPLY;
/*
* Set dport if not defined yet.
*/
if ( ms->flags & IP_MASQ_F_NO_DPORT && ms->protocol == IPPROTO_TCP ) {
ms->flags &= ~IP_MASQ_F_NO_DPORT;
ms->dport = portptr[0];
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("ip_fw_demasquerade(): filled dport=%d\n",
ntohs(ms->dport));
#endif
}
if (ms->flags & IP_MASQ_F_NO_DADDR && ms->protocol == IPPROTO_TCP) {
ms->flags &= ~IP_MASQ_F_NO_DADDR;
ms->daddr = iph->saddr;
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("ip_fw_demasquerade(): filled daddr=%X\n",
ntohs(ms->daddr));
#endif
}
iph->daddr = ms->saddr;
portptr[1] = ms->sport;
/*
* Attempt ip_masq_app call.
* will fix ip_masq and iph ack_seq stuff
*/
if (ip_masq_app_pkt_in(ms, skb_p, dev) != 0)
{
/*
* skb has changed, update pointers.
*/
skb = *skb_p;
iph = skb->h.iph;
portptr = (__u16 *)&(((char *)iph)[iph->ihl*4]);
len = ntohs(iph->tot_len) - (iph->ihl * 4);
}
/*
* Yug! adjust UDP/TCP and IP checksums, also update
* timeouts.
* If a TCP RST is seen collapse the tunnel (by using short timeout)!
*/
if (masq_proto_num(iph->protocol)==0)
{
recalc_check((struct udphdr *)portptr,iph->saddr,iph->daddr,len);
timeout = ip_masq_expire->udp_timeout;
}
else
{
struct tcphdr *th;
skb->csum = csum_partial((void *)(((struct tcphdr *)portptr) + 1),
len - sizeof(struct tcphdr), 0);
tcp_send_check((struct tcphdr *)portptr,iph->saddr,iph->daddr,len,skb);
/* Check if TCP FIN or RST */
th = (struct tcphdr *)portptr;
if (th->fin)
{
ms->flags |= IP_MASQ_F_SAW_FIN_IN;
}
if (th->rst)
{
ms->flags |= IP_MASQ_F_SAW_RST;
}
/* Now set the timeouts */
if (ms->flags & IP_MASQ_F_SAW_RST)
{
timeout = 1;
}
else if ((ms->flags & IP_MASQ_F_SAW_FIN) == IP_MASQ_F_SAW_FIN)
{
timeout = ip_masq_expire->tcp_fin_timeout;
}
else timeout = ip_masq_expire->tcp_timeout;
}
ip_masq_set_expire(ms, timeout);
ip_send_check(iph);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("I-routed to %lX:%X\n",ntohl(iph->daddr),ntohs(portptr[1]));
#endif
return 1;
}
/* sorry, all this trouble for a no-hit :) */
return 0;
}
/*
* /proc/net entries
*/
#ifdef CONFIG_IP_MASQUERADE_IPAUTOFW
static int ip_autofw_procinfo(char *buffer, char **start, off_t offset,
int length, int unused)
{
off_t pos=0, begin=0;
struct ip_autofw * af;
int len=0;
len=sprintf(buffer,"Type Prot Low High Vis Hid Where Last CPto CPrt Timer Flags\n");
for(af = ip_autofw_hosts; af ; af = af->next)
{
len+=sprintf(buffer+len,"%4X %4X %04X-%04X/%04X %04X %08lX %08lX %04X %04X %6lu %4X\n",
af->type,
af->protocol,
af->low,
af->high,
af->visible,
af->hidden,
ntohl(af->where),
ntohl(af->lastcontact),
af->ctlproto,
af->ctlport,
(af->timer.expires<jiffies ? 0 : af->timer.expires-jiffies),
af->flags);
pos=begin+len;
if(pos<offset)
{
len=0;
begin=pos;
}
if(pos>offset+length)
break;
}
*start=buffer+(offset-begin);
len-=(offset-begin);
if(len>length)
len=length;
return len;
}
int ip_fw_demasq_icmp(struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb = *skb_p;
struct iphdr *iph = skb->h.iph;
struct icmphdr *icmph = (struct icmphdr *)((char *)iph + (iph->ihl<<2));
struct iphdr *ciph; /* The ip header contained within the ICMP */
__u16 *pptr; /* port numbers from TCP/UDP contained header */
struct ip_masq *ms;
unsigned short len = ntohs(iph->tot_len) - (iph->ihl * 4);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: icmp in/rev (%d,%d) %lX -> %lX\n",
icmph->type, ntohs(icmp_id(icmph)),
ntohl(iph->saddr), ntohl(iph->daddr));
#endif
#ifdef CONFIG_IP_MASQUERADE_ICMP
if ((icmph->type == ICMP_ECHOREPLY) ||
(icmph->type == ICMP_TIMESTAMPREPLY) ||
(icmph->type == ICMP_INFO_REPLY) ||
(icmph->type == ICMP_ADDRESSREPLY)) {
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: icmp reply rcv %lX->%lX id %d type %d, req %d\n",
ntohl(iph->saddr),
ntohl(iph->daddr),
ntohs(icmp_id(icmph)),
icmph->type,
icmp_type_request(icmph->type));
#endif
ms = ip_masq_in_get_2(iph->protocol,
iph->saddr,
icmp_hv_rep(icmph),
iph->daddr,
icmp_id(icmph));
if (ms == NULL)
return 0;
ip_masq_set_expire(ms,0);
/*
* got reply, so clear flag
*/
ms->flags &= ~IP_MASQ_F_NO_REPLY;
/* Reset source address */
iph->daddr = ms->saddr;
/* Redo IP header checksum */
ip_send_check(iph);
/* Set ID to fake port number */
(icmph->un).echo.id = ms->sport;
/* Reset ICMP checksum and set expiry */
icmph->checksum=0;
icmph->checksum=ip_compute_csum((unsigned char *)icmph,len);
ip_masq_set_expire(ms, MASQUERADE_EXPIRE_ICMP);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: icmp reply rwt %lX->%lX id %d type %d\n",
ntohl(iph->saddr),
ntohl(iph->daddr),
ntohs(icmp_id(icmph)),
icmph->type);
#endif
return 1;
} else {
#endif
if ((icmph->type != ICMP_DEST_UNREACH) &&
(icmph->type != ICMP_SOURCE_QUENCH) &&
(icmph->type != ICMP_TIME_EXCEEDED))
return 0;
#ifdef CONFIG_IP_MASQUERADE_ICMP
}
#endif
/*
* If we get here we have an ICMP error of one of the above 3 types
* Now find the contained IP header
*/
ciph = (struct iphdr *) (icmph + 1);
#ifdef CONFIG_IP_MASQUERADE_ICMP
if (ciph->protocol == IPPROTO_ICMP) {
/*
* This section handles ICMP errors for ICMP packets
*
* First get a new ICMP header structure out of the IP packet
*/
struct icmphdr *cicmph = (struct icmphdr *)((char *)ciph +
(ciph->ihl<<2));
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: rv icmp/icmp rcv %lX->%lX id %d type %d\n",
ntohl(ciph->saddr),
ntohl(ciph->daddr),
ntohs(icmp_id(cicmph)),
cicmph->type);
#endif
ms = ip_masq_in_get_2(ciph->protocol,
ciph->daddr,
icmp_hv_req(cicmph),
ciph->saddr,
icmp_id(cicmph));
if (ms == NULL)
return 0;
/* Now we do real damage to this packet...! */
/* First change the dest IP address, and recalc checksum */
iph->daddr = ms->saddr;
ip_send_check(iph);
/* Now change the *source* address in the contained IP */
ciph->saddr = ms->saddr;
ip_send_check(ciph);
/* Change the ID to the original one! */
(cicmph->un).echo.id = ms->sport;
/* And finally the ICMP checksum */
icmph->checksum = 0;
icmph->checksum = ip_compute_csum((unsigned char *) icmph, len);
#ifdef DEBUG_CONFIG_IP_MASQUERADE_ICMP
printk("MASQ: rv icmp/icmp rwt %lX->%lX id %d type %d\n",
ntohl(ciph->saddr),
ntohl(ciph->daddr),
ntohs(icmp_id(cicmph)),
cicmph->type);
#endif
return 1;
}
#endif /* CONFIG_IP_MASQUERADE_ICMP */
/* We are only interested ICMPs generated from TCP or UDP packets */
if ((ciph->protocol != IPPROTO_UDP) &&
(ciph->protocol != IPPROTO_TCP))
return 0;
/*
* Find the ports involved - remember this packet was
* *outgoing* so the ports are reversed (and addresses)
*/
pptr = (__u16 *)&(((char *)ciph)[ciph->ihl*4]);
if (ntohs(pptr[0]) < PORT_MASQ_BEGIN ||
ntohs(pptr[0]) > PORT_MASQ_END)
return 0;
/* Ensure the checksum is correct */
if (ip_compute_csum((unsigned char *) icmph, len))
{
/* Failed checksum! */
printk(KERN_DEBUG "MASQ: reverse ICMP: failed checksum from %s!\n",
in_ntoa(iph->saddr));
return(-1);
}
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Handling reverse ICMP for %lX:%X -> %lX:%X\n",
ntohl(ciph->saddr), ntohs(pptr[0]),
ntohl(ciph->daddr), ntohs(pptr[1]));
#endif
/* This is pretty much what ip_masq_in_get() does, except params are wrong way round */
ms = ip_masq_in_get_2(ciph->protocol,
ciph->daddr,
pptr[1],
ciph->saddr,
pptr[0]);
if (ms == NULL)
return 0;
/* Now we do real damage to this packet...! */
/* First change the dest IP address, and recalc checksum */
iph->daddr = ms->saddr;
ip_send_check(iph);
/* Now change the *source* address in the contained IP */
ciph->saddr = ms->saddr;
ip_send_check(ciph);
/* the TCP/UDP source port - cannot redo check */
pptr[0] = ms->sport;
/* And finally the ICMP checksum */
icmph->checksum = 0;
icmph->checksum = ip_compute_csum((unsigned char *) icmph, len);
#ifdef DEBUG_CONFIG_IP_MASQUERADE
printk("Rewrote reverse ICMP to %lX:%X -> %lX:%X\n",
ntohl(ciph->saddr), ntohs(pptr[0]),
ntohl(ciph->daddr), ntohs(pptr[1]));
#endif
return 1;
}
int
masq_ftp_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb;
struct iphdr *iph;
struct tcphdr *th;
char *p, *data, *data_limit;
unsigned char p1,p2,p3,p4,p5,p6;
__u32 from;
__u16 port;
struct ip_masq *n_ms;
char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */
unsigned buf_len;
int diff;
skb = *skb_p;
iph = skb->h.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
data_limit = skb->h.raw + skb->len - 18;
if (skb->len >= 6 && (memcmp(data, "PASV\r\n", 6) == 0 || memcmp(data, "pasv\r\n", 6) == 0))
ms->flags |= IP_MASQ_F_FTP_PASV;
while (data < data_limit)
{
if (memcmp(data,"PORT ",5) && memcmp(data,"port ",5))
{
data ++;
continue;
}
p = data+5;
p1 = simple_strtoul(data+5,&data,10);
if (*data!=',')
continue;
p2 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p3 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p4 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p5 = simple_strtoul(data+1,&data,10);
if (*data!=',')
continue;
p6 = simple_strtoul(data+1,&data,10);
if (*data!='\r' && *data!='\n')
continue;
from = (p1<<24) | (p2<<16) | (p3<<8) | p4;
port = (p5<<8) | p6;
#if DEBUG_CONFIG_IP_MASQ_FTP
printk("PORT %X:%X detected\n",from,port);
#endif
/*
* Now update or create an masquerade entry for it
*/
#if DEBUG_CONFIG_IP_MASQ_FTP
printk("protocol %d %lX:%X %X:%X\n", iph->protocol, htonl(from), htons(port), iph->daddr, 0);
#endif
n_ms = ip_masq_out_get_2(iph->protocol,
htonl(from), htons(port),
iph->daddr, 0);
if (n_ms) {
/* existing masquerade, clear timer */
ip_masq_set_expire(n_ms,0);
}
else {
n_ms = ip_masq_new(dev, IPPROTO_TCP,
htonl(from), htons(port),
iph->daddr, 0,
IP_MASQ_F_NO_DPORT);
if (n_ms==NULL)
return 0;
n_ms->control = ms; /* keepalive from data to the control channel */
ms->flags |= IP_MASQ_F_CONTROL; /* this is a control channel */
}
/*
* keep for a bit longer than tcp_fin, caller may not reissue
* PORT before tcp_fin_timeout.
*/
ip_masq_set_expire(n_ms, ip_masq_expire->tcp_fin_timeout*3);
/*
* Replace the old PORT with the new one
*/
from = ntohl(n_ms->maddr);
port = ntohs(n_ms->mport);
sprintf(buf,"%d,%d,%d,%d,%d,%d",
from>>24&255,from>>16&255,from>>8&255,from&255,
port>>8&255,port&255);
buf_len = strlen(buf);
#if DEBUG_CONFIG_IP_MASQ_FTP
printk("new PORT %X:%X\n",from,port);
#endif
/*
* Calculate required delta-offset to keep TCP happy
*/
diff = buf_len - (data-p);
/*
* No shift.
*/
if (diff==0)
{
/*
* simple case, just replace the old PORT cmd
*/
memcpy(p,buf,buf_len);
return 0;
}
*skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC, p, data-p, buf, buf_len);
return diff;
}
return 0;
}
int
masq_ftp_in (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb;
struct iphdr *iph;
struct tcphdr *th;
char *data, *data_limit;
unsigned char p1,p2,p3,p4,p5,p6;
__u32 to;
__u16 port;
struct ip_masq *n_ms;
if (! ms->flags & IP_MASQ_F_FTP_PASV)
return 0; /* quick exit if no outstanding PASV */
skb = *skb_p;
iph = skb->h.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
data_limit = skb->h.raw + skb->len;
while (data < data_limit && *data != ' ')
++data;
while (data < data_limit && *data == ' ')
++data;
data += 22;
if (data >= data_limit || *data != '(')
return 0;
p1 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p2 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p3 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p4 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p5 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ',')
return 0;
p6 = simple_strtoul(data+1, &data, 10);
if (data >= data_limit || *data != ')')
return 0;
to = (p1<<24) | (p2<<16) | (p3<<8) | p4;
port = (p5<<8) | p6;
/*
* Now update or create an masquerade entry for it
*/
#if DEBUG_CONFIG_IP_MASQ_FTP
printk("PASV response %lX:%X %X:%X detected\n", ntohl(ms->saddr), 0, to, port);
#endif
n_ms = ip_masq_out_get_2(iph->protocol,
ms->saddr, 0,
htonl(to), htons(port));
if (n_ms) {
/* existing masquerade, clear timer */
ip_masq_set_expire(n_ms,0);
}
else {
n_ms = ip_masq_new(dev, IPPROTO_TCP,
ms->saddr, 0,
htonl(to), htons(port),
IP_MASQ_F_NO_SPORT);
if (n_ms==NULL)
return 0;
n_ms->control = ms; /* keepalive from data to the control channel */
ms->flags |= IP_MASQ_F_CONTROL; /* this is a control channel */
}
/*
* keep for a bit longer than tcp_fin, client may not issue open
* to server port before tcp_fin_timeout.
*/
ip_masq_set_expire(n_ms, ip_masq_expire->tcp_fin_timeout*3);
ms->flags &= ~IP_MASQ_F_FTP_PASV;
return 0; /* no diff required for incoming packets, thank goodness */
}