/* Generic function for mangling variable-length address changes inside
* NATed UDP connections (like the CONNECT DATA XXXXX MESG XXXXX INDEX XXXXX
* command in the Amanda protocol)
*
* Takes care about all the nasty sequence number changes, checksumming,
* skb enlargement, ...
*
* XXX - This function could be merged with nf_nat_mangle_tcp_packet which
* should be fairly easy to do.
*/
int
nf_nat_mangle_udp_packet(struct sk_buff **pskb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len)
{
struct iphdr *iph;
struct udphdr *udph;
int datalen, oldlen;
/* UDP helpers might accidentally mangle the wrong packet */
iph = (*pskb)->nh.iph;
if ((*pskb)->len < iph->ihl*4 + sizeof(*udph) +
match_offset + match_len)
return 0;
if (!skb_make_writable(pskb, (*pskb)->len))
return 0;
if (rep_len > match_len &&
rep_len - match_len > skb_tailroom(*pskb) &&
!enlarge_skb(pskb, rep_len - match_len))
return 0;
iph = (*pskb)->nh.iph;
udph = (void *)iph + iph->ihl*4;
oldlen = (*pskb)->len - iph->ihl*4;
mangle_contents(*pskb, iph->ihl*4 + sizeof(*udph),
match_offset, match_len, rep_buffer, rep_len);
/* update the length of the UDP packet */
datalen = (*pskb)->len - iph->ihl*4;
udph->len = htons(datalen);
/* fix udp checksum if udp checksum was previously calculated */
if (!udph->check && (*pskb)->ip_summed != CHECKSUM_PARTIAL)
return 1;
if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
udph->check = 0;
udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
datalen, IPPROTO_UDP,
csum_partial((char *)udph,
datalen, 0));
if (!udph->check)
udph->check = CSUM_MANGLED_0;
} else
nf_proto_csum_replace2(&udph->check, *pskb,
htons(oldlen), htons(datalen), 1);
return 1;
}
/* Generic function for mangling variable-length address changes inside
* NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX
* command in FTP).
*
* Takes care about all the nasty sequence number changes, checksumming,
* skb enlargement, ...
*
* */
int
nf_nat_mangle_tcp_packet(struct sk_buff **pskb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len)
{
struct iphdr *iph;
struct tcphdr *tcph;
int oldlen, datalen;
if (!skb_make_writable(pskb, (*pskb)->len))
return 0;
if (rep_len > match_len &&
rep_len - match_len > skb_tailroom(*pskb) &&
!enlarge_skb(pskb, rep_len - match_len))
return 0;
SKB_LINEAR_ASSERT(*pskb);
iph = (*pskb)->nh.iph;
tcph = (void *)iph + iph->ihl*4;
oldlen = (*pskb)->len - iph->ihl*4;
mangle_contents(*pskb, iph->ihl*4 + tcph->doff*4,
match_offset, match_len, rep_buffer, rep_len);
datalen = (*pskb)->len - iph->ihl*4;
if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
tcph->check = 0;
tcph->check = tcp_v4_check(datalen,
iph->saddr, iph->daddr,
csum_partial((char *)tcph,
datalen, 0));
} else
nf_proto_csum_replace2(&tcph->check, *pskb,
htons(oldlen), htons(datalen), 1);
if (rep_len != match_len) {
set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
adjust_tcp_sequence(ntohl(tcph->seq),
(int)rep_len - (int)match_len,
ct, ctinfo);
/* Tell TCP window tracking about seq change */
nf_conntrack_tcp_update(*pskb, (*pskb)->nh.iph->ihl*4,
ct, CTINFO2DIR(ctinfo));
}
return 1;
}
/* Generic function for mangling variable-length address changes inside
* NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX
* command in FTP).
*
* Takes care about all the nasty sequence number changes, checksumming,
* skb enlargement, ...
*
* */
int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len, bool adjust)
{
struct rtable *rt = skb_rtable(skb);
struct iphdr *iph;
struct tcphdr *tcph;
int oldlen, datalen;
unsigned char ipOffSet; //Leo add
if (!skb_make_writable(skb, skb->len))
return 0;
if (rep_len > match_len &&
rep_len - match_len > skb_tailroom(skb) &&
!enlarge_skb(skb, rep_len - match_len))
return 0;
SKB_LINEAR_ASSERT(skb);
iph = ip_hdr(skb);
ipOffSet = iph->ihl << 2;
tcph = (void *)iph + ipOffSet;
oldlen = skb->len - ipOffSet;
mangle_contents(skb, ipOffSet + tcph->doff*4,
match_offset, match_len, rep_buffer, rep_len);
datalen = skb->len - ipOffSet;
if (skb->ip_summed != CHECKSUM_PARTIAL) {
if (!(rt->rt_flags & RTCF_LOCAL) &&
skb->dev->features & NETIF_F_V4_CSUM) {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_headroom(skb) +
skb_network_offset(skb) +
ipOffSet;
skb->csum_offset = offsetof(struct tcphdr, check);
tcph->check = ~tcp_v4_check(datalen,
iph->saddr, iph->daddr, 0);
} else {
/* Generic function for mangling variable-length address changes inside
* NATed UDP connections (like the CONNECT DATA XXXXX MESG XXXXX INDEX XXXXX
* command in the Amanda protocol)
*
* Takes care about all the nasty sequence number changes, checksumming,
* skb enlargement, ...
*
* XXX - This function could be merged with nf_nat_mangle_tcp_packet which
* should be fairly easy to do.
*/
int
nf_nat_mangle_udp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len)
{
struct iphdr *iph;
struct udphdr *udph;
int datalen, oldlen;
/* UDP helpers might accidentally mangle the wrong packet */
iph = ip_hdr(skb);
if (skb->len < iph->ihl*4 + sizeof(*udph) +
match_offset + match_len)
return 0;
if (!skb_make_writable(skb, skb->len))
return 0;
if (rep_len > match_len &&
rep_len - match_len > skb_tailroom(skb) &&
!enlarge_skb(skb, rep_len - match_len))
return 0;
iph = ip_hdr(skb);
udph = (void *)iph + iph->ihl*4;
oldlen = skb->len - iph->ihl*4;
mangle_contents(skb, iph->ihl*4 + sizeof(*udph),
match_offset, match_len, rep_buffer, rep_len);
/* update the length of the UDP packet */
datalen = skb->len - iph->ihl*4;
udph->len = htons(datalen);
/* fix udp checksum if udp checksum was previously calculated */
if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
return 1;
nf_nat_csum(skb, iph, udph, datalen, &udph->check, oldlen);
return 1;
}
int
nf_nat_mangle_udp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len)
{
struct iphdr *iph;
struct udphdr *udph;
int datalen, oldlen;
if (!skb_make_writable(skb, skb->len))
return 0;
if (rep_len > match_len &&
rep_len - match_len > skb_tailroom(skb) &&
!enlarge_skb(skb, rep_len - match_len))
return 0;
iph = ip_hdr(skb);
udph = (void *)iph + iph->ihl*4;
oldlen = skb->len - iph->ihl*4;
mangle_contents(skb, iph->ihl*4 + sizeof(*udph),
match_offset, match_len, rep_buffer, rep_len);
datalen = skb->len - iph->ihl*4;
udph->len = htons(datalen);
if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
return 1;
nf_nat_csum(skb, iph, udph, datalen, &udph->check, oldlen);
return 1;
}
int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int match_offset,
unsigned int match_len,
const char *rep_buffer,
unsigned int rep_len, bool adjust)
{
struct iphdr *iph;
struct tcphdr *tcph;
int oldlen, datalen;
if (!skb_make_writable(skb, skb->len))
return 0;
if (rep_len > match_len &&
rep_len - match_len > skb_tailroom(skb) &&
!enlarge_skb(skb, rep_len - match_len))
return 0;
SKB_LINEAR_ASSERT(skb);
iph = ip_hdr(skb);
tcph = (void *)iph + iph->ihl*4;
oldlen = skb->len - iph->ihl*4;
mangle_contents(skb, iph->ihl*4 + tcph->doff*4,
match_offset, match_len, rep_buffer, rep_len);
datalen = skb->len - iph->ihl*4;
nf_nat_csum(skb, iph, tcph, datalen, &tcph->check, oldlen);
if (adjust && rep_len != match_len)
nf_nat_set_seq_adjust(ct, ctinfo, tcph->seq,
(int)rep_len - (int)match_len);
return 1;
}
