static PptpCallId
AliasVerifyPptp(struct ip *pip, u_int16_t * ptype)
{ /* IP packet to examine/patch */
int hlen, tlen, dlen;
PptpMsgHead hptr;
struct tcphdr *tc;
/* Calculate some lengths */
tc = (struct tcphdr *)ip_next(pip);
hlen = (pip->ip_hl + tc->th_off) << 2;
tlen = ntohs(pip->ip_len);
dlen = tlen - hlen;
/* Verify data length */
if (dlen < (int)(sizeof(struct pptpMsgHead) + sizeof(struct pptpCallIds)))
return (NULL);
/* Move up to PPTP message header */
hptr = (PptpMsgHead) tcp_next(tc);
/* Return the control message type */
*ptype = ntohs(hptr->type);
/* Verify PPTP Control Message */
if ((ntohs(hptr->msgType) != PPTP_CTRL_MSG_TYPE) ||
(ntohl(hptr->magic) != PPTP_MAGIC))
return (NULL);
/* Verify data length. */
if ((*ptype == PPTP_OutCallReply || *ptype == PPTP_InCallReply) &&
(dlen < (int)(sizeof(struct pptpMsgHead) + sizeof(struct pptpCallIds) +
sizeof(struct pptpCodes))))
return (NULL);
else
return (PptpCallId) (hptr + 1);
}
static void
AliasHandleSkinny(struct libalias *la, struct ip *pip, struct alias_link *lnk)
{
size_t hlen, tlen, dlen;
struct tcphdr *tc;
u_int32_t msgId, t, len, lip;
struct skinny_header *sd;
size_t orig_len, skinny_hdr_len = sizeof(struct skinny_header);
ConvDirection direction;
lip = -1;
tc = (struct tcphdr *)ip_next(pip);
hlen = (pip->ip_hl + tc->th_off) << 2;
tlen = ntohs(pip->ip_len);
dlen = tlen - hlen;
sd = (struct skinny_header *)tcp_next(tc);
/*
* XXX This direction is reserved for future use. I still need to
* handle the scenario where the call manager is on the inside, and
* the calling phone is on the global outside.
*/
if (ntohs(tc->th_dport) == la->skinnyPort) {
direction = ClientToServer;
} else if (ntohs(tc->th_sport) == la->skinnyPort) {
direction = ServerToClient;
} else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Invalid port number, not a Skinny packet\n");
#endif
return;
}
orig_len = dlen;
/*
* Skinny packets can contain many messages. We need to loop
* through the packet using len to determine message boundaries.
* This comes into play big time with port messages being in the
* same packet as register messages. Also, open receive channel
* acks are usually buried in a pakcet some 400 bytes long.
*/
while (dlen >= skinny_hdr_len) {
len = (sd->len);
msgId = (sd->msgId);
t = len;
if (t > orig_len || t > dlen) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Not a skinny packet, invalid length \n");
#endif
return;
}
switch (msgId) {
case REG_MSG: {
struct RegisterMessage *reg_mesg;
if (len < (int)sizeof(struct RegisterMessage)) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Not a skinny packet, bad registration message\n");
#endif
return;
}
reg_mesg = (struct RegisterMessage *)&sd->msgId;
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Received a register message");
#endif
alias_skinny_reg_msg(reg_mesg, pip, tc, lnk, direction);
break;
}
case IP_PORT_MSG: {
struct IpPortMessage *port_mesg;
if (len < (int)sizeof(struct IpPortMessage)) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Not a skinny packet, port message\n");
#endif
return;
}
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Received ipport message\n");
#endif
port_mesg = (struct IpPortMessage *)&sd->msgId;
alias_skinny_port_msg(port_mesg, pip, tc, lnk, direction);
break;
}
case OPNRCVCH_ACK: {
struct OpenReceiveChannelAck *opnrcvchn_ack;
if (len < (int)sizeof(struct OpenReceiveChannelAck)) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Not a skinny packet, packet,OpnRcvChnAckMsg\n");
#endif
return;
}
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Received open rcv channel msg\n");
#endif
opnrcvchn_ack = (struct OpenReceiveChannelAck *)&sd->msgId;
alias_skinny_opnrcvch_ack(la, opnrcvchn_ack, pip, tc, lnk, &lip, direction);
break;
}
case START_MEDIATX: {
struct StartMediaTransmission *startmedia_tx;
if (len < (int)sizeof(struct StartMediaTransmission)) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Not a skinny packet,StartMediaTx Message\n");
#endif
return;
}
if (lip == -1) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: received a"
" packet,StartMediaTx Message before"
" packet,OpnRcvChnAckMsg\n"
#endif
return;
}
#ifdef LIBALIAS_DEBUG
fprintf(stderr,
"PacketAlias/Skinny: Received start media trans msg\n");
#endif
startmedia_tx = (struct StartMediaTransmission *)&sd->msgId;
alias_skinny_startmedia(startmedia_tx, pip, tc, lnk, lip, direction);
break;
}
default:
break;
}
/* Place the pointer at the next message in the packet. */
dlen -= len + (skinny_hdr_len - sizeof(msgId));
sd = (struct skinny_header *)(((char *)&sd->msgId) + len);
}
