/*
* Copyright (C) 2012 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* $Id$
*/
#define IPF_RAUDIO_PROXY
void ipf_p_raudio_main_load __P((void));
void ipf_p_raudio_main_unload __P((void));
int ipf_p_raudio_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
int ipf_p_raudio_in __P((void *, fr_info_t *, ap_session_t *, nat_t *));
int ipf_p_raudio_out __P((void *, fr_info_t *, ap_session_t *, nat_t *));
static frentry_t raudiofr;
int raudio_proxy_init = 0;
/*
* Real Audio application proxy initialization.
*/
void
ipf_p_raudio_main_load()
{
bzero((char *)&raudiofr, sizeof(raudiofr));
raudiofr.fr_ref = 1;
raudiofr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&raudiofr.fr_lock, "Real Audio proxy rule lock");
raudio_proxy_init = 1;
}
void
ipf_p_raudio_main_unload()
{
if (raudio_proxy_init == 1) {
MUTEX_DESTROY(&raudiofr.fr_lock);
raudio_proxy_init = 0;
}
}
/*
* Setup for a new proxy to handle Real Audio.
*/
int
ipf_p_raudio_new(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
raudio_t *rap;
nat = nat; /* LINT */
if (fin->fin_v != 4)
return -1;
KMALLOCS(aps->aps_data, void *, sizeof(raudio_t));
if (aps->aps_data == NULL)
return -1;
bzero(aps->aps_data, sizeof(raudio_t));
rap = aps->aps_data;
aps->aps_psiz = sizeof(raudio_t);
rap->rap_mode = RAP_M_TCP; /* default is for TCP */
return 0;
}
int
ipf_p_raudio_out(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
raudio_t *rap = aps->aps_data;
unsigned char membuf[512 + 1], *s;
u_short id = 0;
tcphdr_t *tcp;
int off, dlen;
int len = 0;
mb_t *m;
nat = nat; /* LINT */
/*
* If we've already processed the start messages, then nothing left
* for the proxy to do.
*/
if (rap->rap_eos == 1)
return 0;
m = fin->fin_m;
tcp = (tcphdr_t *)fin->fin_dp;
off = (char *)tcp - (char *)fin->fin_ip;
off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
#ifdef __sgi
dlen = fin->fin_plen - off;
#else
dlen = MSGDSIZE(m) - off;
#endif
if (dlen <= 0)
return 0;
if (dlen > sizeof(membuf))
dlen = sizeof(membuf);
bzero((char *)membuf, sizeof(membuf));
COPYDATA(m, off, dlen, (char *)membuf);
/*
* In all the startup parsing, ensure that we don't go outside
* the packet buffer boundary.
*/
/*
* Look for the start of connection "PNA" string if not seen yet.
*/
if (rap->rap_seenpna == 0) {
s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
if (s == NULL)
return 0;
s += 3;
rap->rap_seenpna = 1;
} else
s = membuf;
/*
* Directly after the PNA will be the version number of this
* connection.
*/
if (rap->rap_seenpna == 1 && rap->rap_seenver == 0) {
if ((s + 1) - membuf < dlen) {
rap->rap_version = (*s << 8) | *(s + 1);
s += 2;
rap->rap_seenver = 1;
} else
return 0;
}
/*
* Now that we've been past the PNA and version number, we're into the
* startup messages block. This ends when a message with an ID of 0.
*/
while ((rap->rap_eos == 0) && ((s + 1) - membuf < dlen)) {
if (rap->rap_gotid == 0) {
id = (*s << 8) | *(s + 1);
s += 2;
rap->rap_gotid = 1;
if (id == RA_ID_END) {
rap->rap_eos = 1;
break;
}
} else if (rap->rap_gotlen == 0) {
len = (*s << 8) | *(s + 1);
s += 2;
rap->rap_gotlen = 1;
}
if (rap->rap_gotid == 1 && rap->rap_gotlen == 1) {
if (id == RA_ID_UDP) {
rap->rap_mode &= ~RAP_M_TCP;
rap->rap_mode |= RAP_M_UDP;
rap->rap_plport = (*s << 8) | *(s + 1);
} else if (id == RA_ID_ROBUST) {
rap->rap_mode |= RAP_M_ROBUST;
rap->rap_prport = (*s << 8) | *(s + 1);
}
s += len;
rap->rap_gotlen = 0;
rap->rap_gotid = 0;
}
}
return 0;
}
int
ipf_p_raudio_in(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
unsigned char membuf[IPF_MAXPORTLEN + 1], *s;
tcphdr_t *tcp, tcph, *tcp2 = &tcph;
raudio_t *rap = aps->aps_data;
ipf_main_softc_t *softc;
ipf_nat_softc_t *softn;
struct in_addr swa, swb;
int off, dlen, slen;
int a1, a2, a3, a4;
u_short sp, dp;
fr_info_t fi;
tcp_seq seq;
nat_t *nat2;
u_char swp;
ip_t *ip;
mb_t *m;
softc = fin->fin_main_soft;
softn = softc->ipf_nat_soft;
/*
* Wait until we've seen the end of the start messages and even then
* only proceed further if we're using UDP. If they want to use TCP
* then data is sent back on the same channel that is already open.
*/
if (rap->rap_sdone != 0)
return 0;
m = fin->fin_m;
tcp = (tcphdr_t *)fin->fin_dp;
off = (char *)tcp - (char *)fin->fin_ip;
off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
#ifdef __sgi
dlen = fin->fin_plen - off;
#else
dlen = MSGDSIZE(m) - off;
#endif
if (dlen <= 0)
return 0;
if (dlen > sizeof(membuf))
dlen = sizeof(membuf);
bzero((char *)membuf, sizeof(membuf));
COPYDATA(m, off, dlen, (char *)membuf);
seq = ntohl(tcp->th_seq);
/*
* Check to see if the data in this packet is of interest to us.
* We only care for the first 19 bytes coming back from the server.
*/
if (rap->rap_sseq == 0) {
s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
if (s == NULL)
return 0;
a1 = s - membuf;
dlen -= a1;
a1 = 0;
rap->rap_sseq = seq;
a2 = MIN(dlen, sizeof(rap->rap_svr));
} else if (seq <= rap->rap_sseq + sizeof(rap->rap_svr)) {
/*
* seq # which is the start of data and from that the offset
* into the buffer array.
*/
a1 = seq - rap->rap_sseq;
a2 = MIN(dlen, sizeof(rap->rap_svr));
a2 -= a1;
s = membuf;
} else
return 0;
for (a3 = a1, a4 = a2; (a4 > 0) && (a3 < 19) && (a3 >= 0); a4--,a3++) {
rap->rap_sbf |= (1 << a3);
rap->rap_svr[a3] = *s++;
}
if ((rap->rap_sbf != 0x7ffff) || (!rap->rap_eos)) /* 19 bits */
return 0;
rap->rap_sdone = 1;
s = (u_char *)rap->rap_svr + 11;
if (((*s << 8) | *(s + 1)) == RA_ID_ROBUST) {
s += 2;
rap->rap_srport = (*s << 8) | *(s + 1);
}
ip = fin->fin_ip;
swp = ip->ip_p;
swa = ip->ip_src;
swb = ip->ip_dst;
ip->ip_p = IPPROTO_UDP;
ip->ip_src = nat->nat_ndstip;
ip->ip_dst = nat->nat_odstip;
bcopy((char *)fin, (char *)&fi, sizeof(fi));
bzero((char *)tcp2, sizeof(*tcp2));
TCP_OFF_A(tcp2, 5);
fi.fin_flx |= FI_IGNORE;
fi.fin_dp = (char *)tcp2;
fi.fin_fr = &raudiofr;
fi.fin_dlen = sizeof(*tcp2);
fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
tcp2->th_win = htons(8192);
slen = ip->ip_len;
ip->ip_len = htons(fin->fin_hlen + sizeof(*tcp));
if (((rap->rap_mode & RAP_M_UDP_ROBUST) == RAP_M_UDP_ROBUST) &&
(rap->rap_srport != 0)) {
dp = rap->rap_srport;
sp = rap->rap_prport;
tcp2->th_sport = htons(sp);
tcp2->th_dport = htons(dp);
fi.fin_data[0] = dp;
fi.fin_data[1] = sp;
fi.fin_out = 0;
MUTEX_ENTER(&softn->ipf_nat_new);
nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
NAT_SLAVE|IPN_UDP | (sp ? 0 : SI_W_SPORT),
NAT_OUTBOUND);
MUTEX_EXIT(&softn->ipf_nat_new);
if (nat2 != NULL) {
(void) ipf_nat_proto(&fi, nat2, IPN_UDP);
MUTEX_ENTER(&nat2->nat_lock);
ipf_nat_update(&fi, nat2);
MUTEX_EXIT(&nat2->nat_lock);
(void) ipf_state_add(softc, &fi, NULL,
(sp ? 0 : SI_W_SPORT));
}
}
if ((rap->rap_mode & RAP_M_UDP) == RAP_M_UDP) {
sp = rap->rap_plport;
tcp2->th_sport = htons(sp);
tcp2->th_dport = 0; /* XXX - don't specify remote port */
fi.fin_data[0] = sp;
fi.fin_data[1] = 0;
fi.fin_out = 1;
MUTEX_ENTER(&softn->ipf_nat_new);
nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
NAT_SLAVE|IPN_UDP|SI_W_DPORT,
NAT_OUTBOUND);
MUTEX_EXIT(&softn->ipf_nat_new);
if (nat2 != NULL) {
(void) ipf_nat_proto(&fi, nat2, IPN_UDP);
MUTEX_ENTER(&nat2->nat_lock);
ipf_nat_update(&fi, nat2);
MUTEX_EXIT(&nat2->nat_lock);
(void) ipf_state_add(softc, &fi, NULL, SI_W_DPORT);
}
}
ip->ip_p = swp;
ip->ip_len = slen;
ip->ip_src = swa;
ip->ip_dst = swb;
return 0;
}
