static int irc_data_fixup(const struct ip_ct_irc_expect *exp_irc_info,
struct ip_conntrack *ct,
struct sk_buff **pskb,
enum ip_conntrack_info ctinfo,
struct ip_conntrack_expect *expect)
{
u_int32_t newip;
struct ip_conntrack_tuple t;
struct iphdr *iph = (*pskb)->nh.iph;
struct tcphdr *tcph = (void *) iph + iph->ihl * 4;
u_int16_t port;
/* "4294967296 65635 " */
char buffer[18];
DEBUGP("IRC_NAT: info (seq %u + %u) in %u\n",
expect->seq, exp_irc_info->len,
ntohl(tcph->seq));
newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
/* Alter conntrack's expectations. */
t = expect->tuple;
t.dst.ip = newip;
for (port = exp_irc_info->port; port != 0; port++) {
t.dst.u.tcp.port = htons(port);
if (ip_conntrack_change_expect(expect, &t) == 0) {
DEBUGP("using port %d", port);
break;
}
}
if (port == 0)
return 0;
/* strlen("\1DCC CHAT chat AAAAAAAA P\1\n")=27
* strlen("\1DCC SCHAT chat AAAAAAAA P\1\n")=28
* strlen("\1DCC SEND F AAAAAAAA P S\1\n")=26
* strlen("\1DCC MOVE F AAAAAAAA P S\1\n")=26
* strlen("\1DCC TSEND F AAAAAAAA P S\1\n")=27
* AAAAAAAAA: bound addr (1.0.0.0==16777216, min 8 digits,
* 255.255.255.255==4294967296, 10 digits)
* P: bound port (min 1 d, max 5d (65635))
* F: filename (min 1 d )
* S: size (min 1 d )
* 0x01, \n: terminators
*/
sprintf(buffer, "%u %u", ntohl(newip), port);
DEBUGP("ip_nat_irc: Inserting '%s' == %u.%u.%u.%u, port %u\n",
buffer, NIPQUAD(newip), port);
return ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
expect->seq - ntohl(tcph->seq),
exp_irc_info->len, buffer,
strlen(buffer));
}
static int set_addr(struct sk_buff **pskb,
unsigned char **data, int dataoff,
unsigned int addroff, __be32 ip, u_int16_t port)
{
enum ip_conntrack_info ctinfo;
struct ip_conntrack *ct = ip_conntrack_get(*pskb, &ctinfo);
struct {
__be32 ip;
__be16 port;
} __attribute__ ((__packed__)) buf;
struct tcphdr _tcph, *th;
buf.ip = ip;
buf.port = htons(port);
addroff += dataoff;
if ((*pskb)->nh.iph->protocol == IPPROTO_TCP) {
if (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
addroff, sizeof(buf),
(char *) &buf, sizeof(buf))) {
if (net_ratelimit())
printk("ip_nat_h323: ip_nat_mangle_tcp_packet"
" error\n");
return -1;
}
/* Relocate data pointer */
th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl * 4,
sizeof(_tcph), &_tcph);
if (th == NULL)
return -1;
*data = (*pskb)->data + (*pskb)->nh.iph->ihl * 4 +
th->doff * 4 + dataoff;
} else {
if (!ip_nat_mangle_udp_packet(pskb, ct, ctinfo,
addroff, sizeof(buf),
(char *) &buf, sizeof(buf))) {
if (net_ratelimit())
printk("ip_nat_h323: ip_nat_mangle_udp_packet"
" error\n");
return -1;
}
/* ip_nat_mangle_udp_packet uses skb_make_writable() to copy
* or pull everything in a linear buffer, so we can safely
* use the skb pointers now */
*data = (*pskb)->data + (*pskb)->nh.iph->ihl * 4 +
sizeof(struct udphdr);
}
return 0;
}
static int sl_remove_port(struct sk_buff **pskb,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo,
unsigned int host_offset,
unsigned int dataoff,
unsigned int datalen,
unsigned int end_of_host,
unsigned char *user_data)
{
if (strncmp(search[PORT].string,
&user_data[end_of_host-search[PORT].len+search[NEWLINE].len],
search[PORT].len)) {
#ifdef SL_DEBUG
printk(KERN_DEBUG "no port rewrite found in packet strncmp\n");
printk(KERN_DEBUG "end of host packet dump:\n%s\n",
(unsigned char *)((unsigned int)user_data+end_of_host-search[PORT].len+search[NEWLINE].len));
#endif
return 0;
}
#ifdef SL_DEBUG
printk(KERN_DEBUG "remove_port found a port at offset %u\n",
end_of_host-search[PORT].len+search[NEWLINE].len );
#endif
/* remove the port */
if (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
end_of_host-search[PORT].len+search[NEWLINE].len,
search[PORT].len-(search[NEWLINE].len*2), // subtract \r\n
NULL,
0))
{
printk(KERN_ERR "unable to remove port needle\n");
// we've already found the port, so we return 1 regardless
return 1;
}
#ifdef SL_DEBUG
printk(KERN_DEBUG "port removed ok, new packet\n%s\n",
(unsigned char *)user_data);
#endif
return 1;
}
static int
mangle_packet(struct sk_buff **pskb,
u_int32_t newip,
unsigned int matchoff,
unsigned int matchlen,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo)
{
unsigned char buffer[4];
MUST_BE_LOCKED(&ip_sc_lock);
*((u_int32_t *)(buffer)) = htonl(newip);
DEBUGP("calling ip_nat_mangle_tcp_packet\n");
return ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, matchoff, matchlen, buffer, 4);
}
/* |1|132.235.1.2|6275| */
static int
mangle_epsv_packet(struct sk_buff **pskb,
u_int32_t newip,
u_int16_t port,
unsigned int matchoff,
unsigned int matchlen,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo,
u32 *seq)
{
char buffer[sizeof("|||65535|")];
sprintf(buffer, "|||%u|", port);
DEBUGP("calling ip_nat_mangle_tcp_packet\n");
*seq += strlen(buffer) - matchlen;
return ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, matchoff,
matchlen, buffer, strlen(buffer));
}
static int
mangle_rfc959_packet(struct sk_buff **pskb,
u_int32_t newip,
u_int16_t port,
unsigned int matchoff,
unsigned int matchlen,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo,
u32 *seq)
{
char buffer[sizeof("nnn,nnn,nnn,nnn,nnn,nnn")];
sprintf(buffer, "%u,%u,%u,%u,%u,%u",
NIPQUAD(newip), port>>8, port&0xFF);
DEBUGP("calling ip_nat_mangle_tcp_packet\n");
*seq += strlen(buffer) - matchlen;
return ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, matchoff,
matchlen, buffer, strlen(buffer));
}
/* inbound packets == from PAC to PNS */
static int
pptp_inbound_pkt(struct sk_buff **pskb,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo,
struct PptpControlHeader *ctlh,
union pptp_ctrl_union *pptpReq)
{
struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
u_int16_t msg, new_cid = 0, new_pcid;
unsigned int pcid_off, cid_off = 0;
int ret = NF_ACCEPT, rv;
new_pcid = htons(nat_pptp_info->pns_call_id);
switch (msg = ntohs(ctlh->messageType)) {
case PPTP_OUT_CALL_REPLY:
pcid_off = offsetof(union pptp_ctrl_union, ocack.peersCallID);
cid_off = offsetof(union pptp_ctrl_union, ocack.callID);
break;
case PPTP_IN_CALL_CONNECT:
pcid_off = offsetof(union pptp_ctrl_union, iccon.peersCallID);
break;
case PPTP_IN_CALL_REQUEST:
/* only need to nat in case PAC is behind NAT box */
return NF_ACCEPT;
case PPTP_WAN_ERROR_NOTIFY:
pcid_off = offsetof(union pptp_ctrl_union, wanerr.peersCallID);
break;
case PPTP_CALL_DISCONNECT_NOTIFY:
pcid_off = offsetof(union pptp_ctrl_union, disc.callID);
break;
case PPTP_SET_LINK_INFO:
pcid_off = offsetof(union pptp_ctrl_union, setlink.peersCallID);
break;
default:
DEBUGP("unknown inbound packet %s\n",
(msg <= PPTP_MSG_MAX)? strMName[msg]:strMName[0]);
/* fall through */
case PPTP_START_SESSION_REQUEST:
case PPTP_START_SESSION_REPLY:
case PPTP_STOP_SESSION_REQUEST:
case PPTP_STOP_SESSION_REPLY:
case PPTP_ECHO_REQUEST:
case PPTP_ECHO_REPLY:
/* no need to alter packet */
return NF_ACCEPT;
}
/* only OUT_CALL_REPLY, IN_CALL_CONNECT, IN_CALL_REQUEST,
* WAN_ERROR_NOTIFY, CALL_DISCONNECT_NOTIFY pass down here */
/* mangle packet */
IP_NF_ASSERT(pcid);
DEBUGP("altering peer call id from 0x%04x to 0x%04x\n",
ntohs(*(u_int16_t *)pptpReq + pcid_off), ntohs(new_pcid));
rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
pcid_off + sizeof(struct pptp_pkt_hdr) +
sizeof(struct PptpControlHeader),
sizeof(new_pcid), (char *)&new_pcid,
sizeof(new_pcid));
if (rv != NF_ACCEPT)
return rv;
if (new_cid) {
DEBUGP("altering call id from 0x%04x to 0x%04x\n",
ntohs(*(u_int16_t *)pptpReq + cid_off), ntohs(new_cid));
rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
cid_off + sizeof(struct pptp_pkt_hdr) +
sizeof(struct PptpControlHeader),
sizeof(new_cid), (char *)&new_cid,
sizeof(new_cid));
if (rv != NF_ACCEPT)
return rv;
}
/* check for earlier return value of 'switch' above */
if (ret != NF_ACCEPT)
return ret;
/* great, at least we don't need to resize packets */
return NF_ACCEPT;
}
/* outbound packets == from PNS to PAC */
static int
pptp_outbound_pkt(struct sk_buff **pskb,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo,
struct PptpControlHeader *ctlh,
union pptp_ctrl_union *pptpReq)
{
struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info;
struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
u_int16_t msg, new_callid;
unsigned int cid_off;
new_callid = htons(ct_pptp_info->pns_call_id);
switch (msg = ntohs(ctlh->messageType)) {
case PPTP_OUT_CALL_REQUEST:
cid_off = offsetof(union pptp_ctrl_union, ocreq.callID);
/* FIXME: ideally we would want to reserve a call ID
* here. current netfilter NAT core is not able to do
* this :( For now we use TCP source port. This breaks
* multiple calls within one control session */
/* save original call ID in nat_info */
nat_pptp_info->pns_call_id = ct_pptp_info->pns_call_id;
/* don't use tcph->source since we are at a DSTmanip
* hook (e.g. PREROUTING) and pkt is not mangled yet */
new_callid = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.tcp.port;
/* save new call ID in ct info */
ct_pptp_info->pns_call_id = ntohs(new_callid);
break;
case PPTP_IN_CALL_REPLY:
cid_off = offsetof(union pptp_ctrl_union, icreq.callID);
break;
case PPTP_CALL_CLEAR_REQUEST:
cid_off = offsetof(union pptp_ctrl_union, clrreq.callID);
break;
default:
DEBUGP("unknown outbound packet 0x%04x:%s\n", msg,
(msg <= PPTP_MSG_MAX)? strMName[msg]:strMName[0]);
/* fall through */
case PPTP_SET_LINK_INFO:
/* only need to NAT in case PAC is behind NAT box */
case PPTP_START_SESSION_REQUEST:
case PPTP_START_SESSION_REPLY:
case PPTP_STOP_SESSION_REQUEST:
case PPTP_STOP_SESSION_REPLY:
case PPTP_ECHO_REQUEST:
case PPTP_ECHO_REPLY:
/* no need to alter packet */
return NF_ACCEPT;
}
/* only OUT_CALL_REQUEST, IN_CALL_REPLY, CALL_CLEAR_REQUEST pass
* down to here */
IP_NF_ASSERT(cid);
DEBUGP("altering call id from 0x%04x to 0x%04x\n",
ntohs(*(u_int16_t *)pptpReq + cid_off), ntohs(new_callid));
/* mangle packet */
if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
cid_off + sizeof(struct pptp_pkt_hdr) +
sizeof(struct PptpControlHeader),
sizeof(new_callid), (char *)&new_callid,
sizeof(new_callid)) == 0)
return NF_DROP;
return NF_ACCEPT;
}
static unsigned int help(struct sk_buff **pskb,
enum ip_conntrack_info ctinfo,
unsigned int matchoff,
unsigned int matchlen,
struct ip_conntrack_expect *exp)
{
u_int16_t port;
unsigned int ret;
/* "4294967296 65635 " */
char buffer[18];
DEBUGP("IRC_NAT: info (seq %u + %u) in %u\n",
expect->seq, exp_irc_info->len,
ntohl(tcph->seq));
/* Reply comes from server. */
exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
exp->dir = IP_CT_DIR_REPLY;
/* When you see the packet, we need to NAT it the same as the
* this one. */
exp->expectfn = ip_nat_follow_master;
/* Try to get same port: if not, try to change it. */
for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
exp->tuple.dst.u.tcp.port = htons(port);
if (ip_conntrack_expect_related(exp) == 0)
break;
}
if (port == 0)
return NF_DROP;
/* strlen("\1DCC CHAT chat AAAAAAAA P\1\n")=27
* strlen("\1DCC SCHAT chat AAAAAAAA P\1\n")=28
* strlen("\1DCC SEND F AAAAAAAA P S\1\n")=26
* strlen("\1DCC MOVE F AAAAAAAA P S\1\n")=26
* strlen("\1DCC TSEND F AAAAAAAA P S\1\n")=27
* AAAAAAAAA: bound addr (1.0.0.0==16777216, min 8 digits,
* 255.255.255.255==4294967296, 10 digits)
* P: bound port (min 1 d, max 5d (65635))
* F: filename (min 1 d )
* S: size (min 1 d )
* 0x01, \n: terminators
*/
/* AAA = "us", ie. where server normally talks to. */
sprintf(buffer, "%u %u",
ntohl(exp->master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip),
port);
DEBUGP("ip_nat_irc: Inserting '%s' == %u.%u.%u.%u, port %u\n",
buffer, NIPQUAD(exp->tuple.src.ip), port);
ret = ip_nat_mangle_tcp_packet(pskb, exp->master, ctinfo,
matchoff, matchlen, buffer,
strlen(buffer));
if (ret != NF_ACCEPT)
ip_conntrack_unexpect_related(exp);
return ret;
}
static int mms_data_fixup(const struct ip_ct_mms_expect *ct_mms_info,
struct ip_conntrack *ct,
struct sk_buff **pskb,
enum ip_conntrack_info ctinfo,
struct ip_conntrack_expect *expect)
{
u_int32_t newip;
struct ip_conntrack_tuple t;
struct iphdr *iph = (*pskb)->nh.iph;
struct tcphdr *tcph = (void *) iph + iph->ihl * 4;
char *data = (char *)tcph + tcph->doff * 4;
int i, j, k, port;
u_int16_t mms_proto;
u_int32_t *mms_chunkLenLV = (u_int32_t *)(data + MMS_SRV_CHUNKLENLV_OFFSET);
u_int32_t *mms_chunkLenLM = (u_int32_t *)(data + MMS_SRV_CHUNKLENLM_OFFSET);
u_int32_t *mms_messageLength = (u_int32_t *)(data + MMS_SRV_MESSAGELENGTH_OFFSET);
int zero_padding;
char buffer[28]; /* "\\255.255.255.255\UDP\65635" * 2 (for unicode) */
char unicode_buffer[75]; /* 27*2 (unicode) + 20 + 1 */
char proto_string[6];
/* what was the protocol again ? */
mms_proto = expect->tuple.dst.protonum;
sprintf(proto_string, "%u", mms_proto);
DEBUGP("ip_nat_mms: mms_data_fixup: info (seq %u + %u) in %u, proto %s\n",
expect->seq, ct_mms_info->len, ntohl(tcph->seq),
mms_proto == IPPROTO_UDP ? "UDP"
: mms_proto == IPPROTO_TCP ? "TCP":proto_string);
newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
/* Alter conntrack's expectations. */
t = expect->tuple;
t.dst.ip = newip;
for (port = ct_mms_info->port; port != 0; port++) {
t.dst.u.tcp.port = htons(port);
if (ip_conntrack_change_expect(expect, &t) == 0) {
DEBUGP("ip_nat_mms: mms_data_fixup: using port %d\n", port);
break;
}
}
if(port == 0)
return 0;
sprintf(buffer, "\\\\%u.%u.%u.%u\\%s\\%u",
NIPQUAD(newip),
expect->tuple.dst.protonum == IPPROTO_UDP ? "UDP"
: expect->tuple.dst.protonum == IPPROTO_TCP ? "TCP":proto_string,
port);
DEBUGP("ip_nat_mms: new unicode string=%s\n", buffer);
memset(unicode_buffer, 0, sizeof(char)*75);
for (i=0; i<strlen(buffer); ++i)
*(unicode_buffer+i*2)=*(buffer+i);
DEBUGP("ip_nat_mms: mms_data_fixup: padding: %u len: %u\n", ct_mms_info->padding, ct_mms_info->len);
DEBUGP("ip_nat_mms: mms_data_fixup: offset: %u\n", MMS_SRV_UNICODE_STRING_OFFSET+ct_mms_info->len);
DUMP_BYTES(data+MMS_SRV_UNICODE_STRING_OFFSET, 60);
/* add end of packet to it */
for (j=0; j<ct_mms_info->padding; ++j) {
DEBUGP("ip_nat_mms: mms_data_fixup: i=%u j=%u byte=%u\n",
i, j, (u8)*(data+MMS_SRV_UNICODE_STRING_OFFSET+ct_mms_info->len+j));
*(unicode_buffer+i*2+j) = *(data+MMS_SRV_UNICODE_STRING_OFFSET+ct_mms_info->len+j);
}
/* pad with zeroes at the end ? see explanation of weird math below */
zero_padding = (8-(strlen(buffer)*2 + ct_mms_info->padding + 4)%8)%8;
for (k=0; k<zero_padding; ++k)
*(unicode_buffer+i*2+j+k)= (char)0;
DEBUGP("ip_nat_mms: mms_data_fixup: zero_padding = %u\n", zero_padding);
DEBUGP("ip_nat_mms: original=> chunkLenLV=%u chunkLenLM=%u messageLength=%u\n",
*mms_chunkLenLV, *mms_chunkLenLM, *mms_messageLength);
/* explanation, before I forget what I did:
strlen(buffer)*2 + ct_mms_info->padding + 4 must be divisable by 8;
divide by 8 and add 3 to compute the mms_chunkLenLM field,
but note that things may have to be padded with zeroes to align by 8
bytes, hence we add 7 and divide by 8 to get the correct length */
*mms_chunkLenLM = (u_int32_t) (3+(strlen(buffer)*2+ct_mms_info->padding+11)/8);
*mms_chunkLenLV = *mms_chunkLenLM+2;
*mms_messageLength = *mms_chunkLenLV*8;
DEBUGP("ip_nat_mms: modified=> chunkLenLV=%u chunkLenLM=%u messageLength=%u\n",
*mms_chunkLenLV, *mms_chunkLenLM, *mms_messageLength);
ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
expect->seq - ntohl(tcph->seq),
ct_mms_info->len + ct_mms_info->padding, unicode_buffer,
strlen(buffer)*2 + ct_mms_info->padding + zero_padding);
DUMP_BYTES(unicode_buffer, 60);
return 1;
}
static unsigned int add_sl_header(struct sk_buff **pskb,
struct ip_conntrack *ct,
enum ip_conntrack_info ctinfo,
unsigned int host_offset,
unsigned int dataoff,
unsigned int datalen,
unsigned int end_of_host,
unsigned char *user_data)
{
unsigned int jhashed, slheader_len;
char src_string[MACADDR_SIZE], slheader[SL_HEADER_LEN];
struct ethhdr *bigmac = eth_hdr(*pskb);
/* first make sure there is room */
if ( (*pskb)->len >= ( MAX_PACKET_LEN - SL_HEADER_LEN ) ) {
#ifdef SL_DEBUG
printk(KERN_DEBUG "packet too large for sl_header, length: %d\n", (*pskb)->len);
#endif
return 0;
}
/* next make sure an x-slr header is not already present */
if (!strncmp(xslr,(unsigned char *)((unsigned int)user_data+end_of_host+1),
XSLR_LEN)) {
#ifdef SL_DEBUG
printk(KERN_DEBUG "pkt x-slr already present\n");
#endif
return 0;
}
#ifdef SL_DEBUG
printk(KERN_DEBUG "no x-slr header present, adding\n");
#endif
/* create the X-SLR Header */
#ifdef SL_DEBUG
printk(KERN_DEBUG "source mac found: %02x%02x%02x%02x%02x%02x\n",
bigmac->h_source[0],
bigmac->h_source[1],
bigmac->h_source[2],
bigmac->h_source[3],
bigmac->h_source[4],
bigmac->h_source[5]);
#endif
sprintf(src_string, "%02x%02x%02x%02x%02x%02x",
bigmac->h_source[0],
bigmac->h_source[1],
bigmac->h_source[2],
bigmac->h_source[3],
bigmac->h_source[4],
bigmac->h_source[5]);
/********************************************/
/* create the http header */
/* jenkins hash obfuscation of source mac */
jhashed = jhash((void *)src_string, MACADDR_SIZE, JHASH_SALT);
slheader_len = sprintf(slheader, "X-SLR: %08x|%s\r\n", jhashed, sl_device);
/* handle sprintf failure */
if (slheader_len != SL_HEADER_LEN) {
printk(KERN_ERR "exp header %s len %d doesnt match calc len %d\n",
(char *)slheader, SL_HEADER_LEN, slheader_len );
return 0;
}
#ifdef SL_DEBUG
printk(KERN_DEBUG "xslr %s, len %d\n", slheader, slheader_len);
#endif
/********************************************/
/* insert the slheader into the http headers */
if (!ip_nat_mangle_tcp_packet( pskb,
ct,
ctinfo,
end_of_host + search[NEWLINE].len,
0,
slheader,
slheader_len)) {
printk(KERN_ERR " failed to mangle packet\n");
return 0;
}
#ifdef SL_DEBUG
printk(KERN_DEBUG "packet mangled ok:\n%s\n",
(unsigned char *)((unsigned int)user_data));
#endif
return 1;
}
