static int
protohandler(struct libalias *la, struct ip *pip, struct alias_data *ah)
{
if (ntohs(*ah->dport) == TFTP_PORT_NUMBER)
FindRtspOut(la, pip->ip_src, pip->ip_dst,
*ah->sport, *ah->aport, IPPROTO_UDP);
else AliasHandleRtspOut(la, pip, ah->lnk, ah->maxpktsize);
return (0);
}
static int
alias_rtsp_out(struct libalias *la, struct ip *pip,
struct alias_link *lnk,
char *data,
const char *port_str)
{
int hlen, tlen, dlen;
struct tcphdr *tc;
int i, j, pos, state, port_dlen, new_dlen, delta;
u_short p[2], new_len;
u_short sport, eport, base_port;
u_short salias = 0, ealias = 0, base_alias = 0;
const char *transport_str = "transport:";
char newdata[2048], *port_data, *port_newdata, stemp[80];
int links_created = 0, pkt_updated = 0;
struct alias_link *rtsp_lnk = NULL;
struct in_addr null_addr;
/* Calculate data length of TCP packet */
tc = (struct tcphdr *)ip_next(pip);
hlen = (pip->ip_hl + tc->th_off) << 2;
tlen = ntohs(pip->ip_len);
dlen = tlen - hlen;
/* Find keyword, "Transport: " */
pos = search_string(data, dlen, transport_str);
if (pos < 0) {
return (-1);
}
port_data = data + pos;
port_dlen = dlen - pos;
memcpy(newdata, data, pos);
port_newdata = newdata + pos;
while (port_dlen > (int)strlen(port_str)) {
/* Find keyword, appropriate port string */
pos = search_string(port_data, port_dlen, port_str);
if (pos < 0) {
break;
}
memcpy(port_newdata, port_data, pos + 1);
port_newdata += (pos + 1);
p[0] = p[1] = 0;
sport = eport = 0;
state = 0;
for (i = pos; i < port_dlen; i++) {
switch (state) {
case 0:
if (port_data[i] == '=') {
state++;
}
break;
case 1:
if (ISDIGIT(port_data[i])) {
p[0] = p[0] * 10 + port_data[i] - '0';
} else {
if (port_data[i] == ';') {
state = 3;
}
if (port_data[i] == '-') {
state++;
}
}
break;
case 2:
if (ISDIGIT(port_data[i])) {
p[1] = p[1] * 10 + port_data[i] - '0';
} else {
state++;
}
break;
case 3:
base_port = p[0];
sport = htons(p[0]);
eport = htons(p[1]);
if (!links_created) {
links_created = 1;
/*
* Find an even numbered port
* number base that satisfies the
* contiguous number of ports we
* need
*/
null_addr.s_addr = 0;
if (0 == (salias = FindNewPortGroup(la, null_addr,
FindAliasAddress(la, pip->ip_src),
sport, 0,
RTSP_PORT_GROUP,
IPPROTO_UDP, 1))) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/RTSP: Cannot find contiguous RTSP data ports\n");
#endif
} else {
base_alias = ntohs(salias);
for (j = 0; j < RTSP_PORT_GROUP; j++) {
/*
* Establish link
* to port found in
* RTSP packet
*/
rtsp_lnk = FindRtspOut(la, GetOriginalAddress(lnk), null_addr,
htons(base_port + j), htons(base_alias + j),
IPPROTO_UDP);
if (rtsp_lnk != NULL) {
#ifndef NO_FW_PUNCH
/*
* Punch
* hole in
* firewall
*/
PunchFWHole(rtsp_lnk);
#endif
} else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/RTSP: Cannot allocate RTSP data ports\n");
#endif
break;
}
}
}
ealias = htons(base_alias + (RTSP_PORT_GROUP - 1));
}
if (salias && rtsp_lnk) {
pkt_updated = 1;
/* Copy into IP packet */
sprintf(stemp, "%d", ntohs(salias));
memcpy(port_newdata, stemp, strlen(stemp));
port_newdata += strlen(stemp);
if (eport != 0) {
*port_newdata = '-';
port_newdata++;
/* Copy into IP packet */
sprintf(stemp, "%d", ntohs(ealias));
memcpy(port_newdata, stemp, strlen(stemp));
port_newdata += strlen(stemp);
}
*port_newdata = ';';
port_newdata++;
}
state++;
break;
}
if (state > 3) {
break;
}
}
port_data += i;
port_dlen -= i;
}
if (!pkt_updated)
return (-1);
memcpy(port_newdata, port_data, port_dlen);
port_newdata += port_dlen;
*port_newdata = '\0';
/* Create new packet */
new_dlen = port_newdata - newdata;
memcpy(data, newdata, new_dlen);
SetAckModified(lnk);
tc = (struct tcphdr *)ip_next(pip);
delta = GetDeltaSeqOut(tc->th_seq, lnk);
AddSeq(lnk, delta + new_dlen - dlen, pip->ip_hl, pip->ip_len,
tc->th_seq, tc->th_off);
new_len = htons(hlen + new_dlen);
DifferentialChecksum(&pip->ip_sum,
&new_len,
&pip->ip_len,
1);
pip->ip_len = new_len;
tc->th_sum = 0;
#ifdef _KERNEL
tc->th_x2 = 1;
#else
tc->th_sum = TcpChecksum(pip);
#endif
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);
}
