static void
AliasHandleCUSeeMeIn(struct libalias *la, struct ip *pip, struct in_addr original_addr)
{
struct in_addr alias_addr;
struct udphdr *ud;
struct cu_header *cu;
struct oc_header *oc;
struct client_info *ci;
char *end;
int i;
(void)la;
alias_addr.s_addr = pip->ip_dst.s_addr;
ud = ip_next(pip);
cu = udp_next(ud);
oc = (struct oc_header *)(cu + 1);
ci = (struct client_info *)(oc + 1);
end = (char *)ud + ntohs(ud->uh_ulen);
if ((char *)oc <= end) {
if (cu->dest_addr)
cu->dest_addr = (u_int32_t) original_addr.s_addr;
if (ntohs(cu->data_type) == 101)
/* Find and change our address */
for (i = 0; (char *)(ci + 1) <= end && i < oc->client_count; i++, ci++)
if (ci->address == (u_int32_t) alias_addr.s_addr) {
ci->address = (u_int32_t) original_addr.s_addr;
break;
}
}
}
static void
AliasHandleCUSeeMeOut(struct libalias *la, struct ip *pip, struct alias_link *lnk)
{
struct udphdr *ud = ip_next(pip);
if (ntohs(ud->uh_ulen) - sizeof(struct udphdr) >= sizeof(struct cu_header)) {
struct cu_header *cu;
struct alias_link *cu_lnk;
cu = udp_next(ud);
if (cu->addr)
cu->addr = (u_int32_t) GetAliasAddress(lnk).s_addr;
cu_lnk = FindUdpTcpOut(la, pip->ip_src, GetDestAddress(lnk),
ud->uh_dport, 0, IPPROTO_UDP, 1);
#ifndef NO_FW_PUNCH
if (cu_lnk)
PunchFWHole(cu_lnk);
#endif
}
}
static int
AliasHandleUdpNbt(
struct libalias *la,
struct ip *pip, /* IP packet to examine/patch */
struct alias_link *lnk,
struct in_addr *alias_address,
u_short alias_port
)
{
struct udphdr *uh;
NbtDataHeader *ndh;
u_char *p = NULL;
char *pmax;
#ifdef LIBALIAS_DEBUG
char addrbuf[INET_ADDRSTRLEN];
#endif
(void)la;
(void)lnk;
/* Calculate data length of UDP packet */
uh = (struct udphdr *)ip_next(pip);
pmax = (char *)uh + ntohs(uh->uh_ulen);
ndh = (NbtDataHeader *)udp_next(uh);
if ((char *)(ndh + 1) > pmax)
return (-1);
#ifdef LIBALIAS_DEBUG
printf("\nType=%02x,", ndh->type);
#endif
switch (ndh->type) {
case DGM_DIRECT_UNIQ:
case DGM_DIRECT_GROUP:
case DGM_BROADCAST:
p = (u_char *) ndh + 14;
p = AliasHandleName(p, pmax); /* Source Name */
p = AliasHandleName(p, pmax); /* Destination Name */
break;
case DGM_ERROR:
p = (u_char *) ndh + 11;
break;
case DGM_QUERY:
case DGM_POSITIVE_RES:
case DGM_NEGATIVE_RES:
p = (u_char *) ndh + 10;
p = AliasHandleName(p, pmax); /* Destination Name */
break;
}
if (p == NULL || (char *)p > pmax)
p = NULL;
#ifdef LIBALIAS_DEBUG
printf("%s:%d-->", inet_ntoa_r(ndh->source_ip, INET_NTOA_BUF(addrbuf)),
ntohs(ndh->source_port));
#endif
/* Doing an IP address and Port number Translation */
if (uh->uh_sum != 0) {
int acc;
u_short *sptr;
acc = ndh->source_port;
acc -= alias_port;
sptr = (u_short *) & (ndh->source_ip);
acc += *sptr++;
acc += *sptr;
sptr = (u_short *) alias_address;
acc -= *sptr++;
acc -= *sptr;
ADJUST_CHECKSUM(acc, uh->uh_sum);
}
ndh->source_ip = *alias_address;
ndh->source_port = alias_port;
#ifdef LIBALIAS_DEBUG
printf("%s:%d\n", inet_ntoa_r(ndh->source_ip, INET_NTOA_BUF(addrbuf)),
ntohs(ndh->source_port));
fflush(stdout);
#endif
return ((p == NULL) ? -1 : 0);
}
