static int
protohandler2out(struct libalias *la, struct ip *pip, struct alias_data *ah)
{
return (AliasHandleUdpNbtNS(la, pip, ah->lnk, &pip->ip_src, ah->sport,
ah->aaddr, ah->aport));
}
static int
protohandler2in(struct libalias *la, struct ip *pip, struct alias_data *ah)
{
AliasHandleUdpNbtNS(la, pip, ah->lnk, ah->aaddr, ah->aport,
ah->oaddr, ah->dport);
return (0);
}
static int
UdpAliasOut(struct ip *pip)
{
struct udphdr *ud;
struct alias_link *link;
/* Return if proxy-only mode is enabled */
if (packetAliasMode & PKT_ALIAS_PROXY_ONLY)
return PKT_ALIAS_OK;
ud = (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
link = FindUdpTcpOut(pip->ip_src, pip->ip_dst,
ud->uh_sport, ud->uh_dport,
IPPROTO_UDP, 1);
if (link != NULL)
{
u_short alias_port;
struct in_addr alias_address;
alias_address = GetAliasAddress(link);
alias_port = GetAliasPort(link);
/* Special processing for IP encoding protocols */
if (ntohs(ud->uh_dport) == CUSEEME_PORT_NUMBER)
AliasHandleCUSeeMeOut(pip, link);
/* If NETBIOS Datagram, It should be alias address in UDP Data, too */
else if (ntohs(ud->uh_dport) == NETBIOS_DGM_PORT_NUMBER
|| ntohs(ud->uh_sport) == NETBIOS_DGM_PORT_NUMBER)
AliasHandleUdpNbt(pip, link, &alias_address, alias_port);
else if (ntohs(ud->uh_dport) == NETBIOS_NS_PORT_NUMBER
|| ntohs(ud->uh_sport) == NETBIOS_NS_PORT_NUMBER)
AliasHandleUdpNbtNS(pip, link, &pip->ip_src, &ud->uh_sport,
&alias_address, &alias_port);
/*
* We don't know in advance what TID the TFTP server will choose,
* so we create a wilcard link (destination port is unspecified)
* that will match any TID from a given destination.
*/
else if (ntohs(ud->uh_dport) == TFTP_PORT_NUMBER)
FindRtspOut(pip->ip_src, pip->ip_dst,
ud->uh_sport, alias_port, IPPROTO_UDP);
/* If UDP checksum is not zero, adjust since source port is */
/* being aliased and source address is being altered */
if (ud->uh_sum != 0)
{
int accumulate;
u_short *sptr;
accumulate = ud->uh_sport;
accumulate -= alias_port;
sptr = (u_short *) &(pip->ip_src);
accumulate += *sptr++;
accumulate += *sptr;
sptr = (u_short *) &alias_address;
accumulate -= *sptr++;
accumulate -= *sptr;
ADJUST_CHECKSUM(accumulate, ud->uh_sum);
}
/* Put alias port in UDP header */
ud->uh_sport = alias_port;
/* Change source address */
DifferentialChecksum(&pip->ip_sum,
(u_short *) &alias_address,
(u_short *) &pip->ip_src,
2);
pip->ip_src = alias_address;
return(PKT_ALIAS_OK);
}
return(PKT_ALIAS_IGNORED);
}
static int
UdpAliasIn(struct ip *pip)
{
struct udphdr *ud;
struct alias_link *link;
/* Return if proxy-only mode is enabled */
if (packetAliasMode & PKT_ALIAS_PROXY_ONLY)
return PKT_ALIAS_OK;
ud = (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
link = FindUdpTcpIn(pip->ip_src, pip->ip_dst,
ud->uh_sport, ud->uh_dport,
IPPROTO_UDP, 1);
if (link != NULL)
{
struct in_addr alias_address;
struct in_addr original_address;
u_short alias_port;
int accumulate;
u_short *sptr;
int r = 0;
alias_address = GetAliasAddress(link);
original_address = GetOriginalAddress(link);
alias_port = ud->uh_dport;
ud->uh_dport = GetOriginalPort(link);
/* Special processing for IP encoding protocols */
if (ntohs(ud->uh_dport) == CUSEEME_PORT_NUMBER)
AliasHandleCUSeeMeIn(pip, original_address);
/* If NETBIOS Datagram, It should be alias address in UDP Data, too */
else if (ntohs(ud->uh_dport) == NETBIOS_DGM_PORT_NUMBER
|| ntohs(ud->uh_sport) == NETBIOS_DGM_PORT_NUMBER)
r = AliasHandleUdpNbt(pip, link, &original_address, ud->uh_dport);
else if (ntohs(ud->uh_dport) == NETBIOS_NS_PORT_NUMBER
|| ntohs(ud->uh_sport) == NETBIOS_NS_PORT_NUMBER)
r = AliasHandleUdpNbtNS(pip, link, &alias_address, &alias_port,
&original_address, &ud->uh_dport);
/* If UDP checksum is not zero, then adjust since destination port */
/* is being unaliased and destination address is being altered. */
if (ud->uh_sum != 0)
{
accumulate = alias_port;
accumulate -= ud->uh_dport;
sptr = (u_short *) &alias_address;
accumulate += *sptr++;
accumulate += *sptr;
sptr = (u_short *) &original_address;
accumulate -= *sptr++;
accumulate -= *sptr;
ADJUST_CHECKSUM(accumulate, ud->uh_sum);
}
/* Restore original IP address */
DifferentialChecksum(&pip->ip_sum,
(u_short *) &original_address,
(u_short *) &pip->ip_dst,
2);
pip->ip_dst = original_address;
/*
* If we cannot figure out the packet, ignore it.
*/
if (r < 0)
return(PKT_ALIAS_IGNORED);
else
return(PKT_ALIAS_OK);
}
return(PKT_ALIAS_IGNORED);
}
