342 lines
7.6 KiB
C
342 lines
7.6 KiB
C
/* $NetBSD: ip_raudio_pxy.c,v 1.2 2005/02/19 21:30:25 martti Exp $ */
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#include <sys/cdefs.h>
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__KERNEL_RCSID(1, "$NetBSD: ip_raudio_pxy.c,v 1.2 2005/02/19 21:30:25 martti Exp $");
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/*
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* Copyright (C) 1998-2003 by Darren Reed
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*
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* See the IPFILTER.LICENCE file for details on licencing.
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*
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* Id: ip_raudio_pxy.c,v 1.40.2.3 2005/02/04 10:22:55 darrenr Exp
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*/
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#define IPF_RAUDIO_PROXY
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int ippr_raudio_init __P((void));
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void ippr_raudio_fini __P((void));
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int ippr_raudio_new __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_raudio_in __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_raudio_out __P((fr_info_t *, ap_session_t *, nat_t *));
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static frentry_t raudiofr;
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int raudio_proxy_init = 0;
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/*
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* Real Audio application proxy initialization.
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*/
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int ippr_raudio_init()
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{
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bzero((char *)&raudiofr, sizeof(raudiofr));
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raudiofr.fr_ref = 1;
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raudiofr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
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MUTEX_INIT(&raudiofr.fr_lock, "Real Audio proxy rule lock");
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raudio_proxy_init = 1;
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return 0;
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}
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void ippr_raudio_fini()
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{
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if (raudio_proxy_init == 1) {
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MUTEX_DESTROY(&raudiofr.fr_lock);
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raudio_proxy_init = 0;
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}
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}
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/*
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* Setup for a new proxy to handle Real Audio.
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*/
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int ippr_raudio_new(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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raudio_t *rap;
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KMALLOCS(aps->aps_data, void *, sizeof(raudio_t));
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if (aps->aps_data == NULL)
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return -1;
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fin = fin; /* LINT */
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nat = nat; /* LINT */
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bzero(aps->aps_data, sizeof(raudio_t));
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rap = aps->aps_data;
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aps->aps_psiz = sizeof(raudio_t);
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rap->rap_mode = RAP_M_TCP; /* default is for TCP */
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return 0;
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}
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int ippr_raudio_out(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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raudio_t *rap = aps->aps_data;
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unsigned char membuf[512 + 1], *s;
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u_short id = 0;
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tcphdr_t *tcp;
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int off, dlen;
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int len = 0;
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mb_t *m;
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nat = nat; /* LINT */
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/*
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* If we've already processed the start messages, then nothing left
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* for the proxy to do.
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*/
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if (rap->rap_eos == 1)
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return 0;
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m = fin->fin_m;
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tcp = (tcphdr_t *)fin->fin_dp;
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off = (char *)tcp - (char *)fin->fin_ip;
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off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
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#ifdef __sgi
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dlen = fin->fin_plen - off;
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#else
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dlen = MSGDSIZE(m) - off;
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#endif
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if (dlen <= 0)
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return 0;
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if (dlen > sizeof(membuf))
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dlen = sizeof(membuf);
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bzero((char *)membuf, sizeof(membuf));
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COPYDATA(m, off, dlen, (char *)membuf);
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/*
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* In all the startup parsing, ensure that we don't go outside
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* the packet buffer boundary.
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*/
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/*
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* Look for the start of connection "PNA" string if not seen yet.
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*/
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if (rap->rap_seenpna == 0) {
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s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
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if (s == NULL)
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return 0;
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s += 3;
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rap->rap_seenpna = 1;
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} else
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s = membuf;
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/*
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* Directly after the PNA will be the version number of this
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* connection.
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*/
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if (rap->rap_seenpna == 1 && rap->rap_seenver == 0) {
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if ((s + 1) - membuf < dlen) {
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rap->rap_version = (*s << 8) | *(s + 1);
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s += 2;
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rap->rap_seenver = 1;
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} else
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return 0;
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}
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/*
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* Now that we've been past the PNA and version number, we're into the
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* startup messages block. This ends when a message with an ID of 0.
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*/
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while ((rap->rap_eos == 0) && ((s + 1) - membuf < dlen)) {
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if (rap->rap_gotid == 0) {
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id = (*s << 8) | *(s + 1);
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s += 2;
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rap->rap_gotid = 1;
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if (id == RA_ID_END) {
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rap->rap_eos = 1;
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break;
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}
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} else if (rap->rap_gotlen == 0) {
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len = (*s << 8) | *(s + 1);
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s += 2;
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rap->rap_gotlen = 1;
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}
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if (rap->rap_gotid == 1 && rap->rap_gotlen == 1) {
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if (id == RA_ID_UDP) {
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rap->rap_mode &= ~RAP_M_TCP;
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rap->rap_mode |= RAP_M_UDP;
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rap->rap_plport = (*s << 8) | *(s + 1);
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} else if (id == RA_ID_ROBUST) {
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rap->rap_mode |= RAP_M_ROBUST;
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rap->rap_prport = (*s << 8) | *(s + 1);
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}
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s += len;
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rap->rap_gotlen = 0;
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rap->rap_gotid = 0;
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}
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}
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return 0;
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}
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int ippr_raudio_in(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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unsigned char membuf[IPF_MAXPORTLEN + 1], *s;
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tcphdr_t *tcp, tcph, *tcp2 = &tcph;
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raudio_t *rap = aps->aps_data;
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struct in_addr swa, swb;
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int off, dlen, slen;
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int a1, a2, a3, a4;
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u_short sp, dp;
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fr_info_t fi;
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tcp_seq seq;
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nat_t *nat2;
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u_char swp;
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ip_t *ip;
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mb_t *m;
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/*
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* Wait until we've seen the end of the start messages and even then
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* only proceed further if we're using UDP. If they want to use TCP
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* then data is sent back on the same channel that is already open.
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*/
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if (rap->rap_sdone != 0)
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return 0;
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m = fin->fin_m;
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tcp = (tcphdr_t *)fin->fin_dp;
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off = (char *)tcp - (char *)fin->fin_ip;
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off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
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#ifdef __sgi
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dlen = fin->fin_plen - off;
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#else
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dlen = MSGDSIZE(m) - off;
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#endif
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if (dlen <= 0)
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return 0;
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if (dlen > sizeof(membuf))
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dlen = sizeof(membuf);
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bzero((char *)membuf, sizeof(membuf));
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COPYDATA(m, off, dlen, (char *)membuf);
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seq = ntohl(tcp->th_seq);
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/*
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* Check to see if the data in this packet is of interest to us.
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* We only care for the first 19 bytes coming back from the server.
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*/
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if (rap->rap_sseq == 0) {
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s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
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if (s == NULL)
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return 0;
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a1 = s - membuf;
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dlen -= a1;
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a1 = 0;
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rap->rap_sseq = seq;
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a2 = MIN(dlen, sizeof(rap->rap_svr));
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} else if (seq <= rap->rap_sseq + sizeof(rap->rap_svr)) {
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/*
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* seq # which is the start of data and from that the offset
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* into the buffer array.
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*/
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a1 = seq - rap->rap_sseq;
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a2 = MIN(dlen, sizeof(rap->rap_svr));
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a2 -= a1;
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s = membuf;
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} else
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return 0;
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for (a3 = a1, a4 = a2; (a4 > 0) && (a3 < 19) && (a3 >= 0); a4--,a3++) {
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rap->rap_sbf |= (1 << a3);
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rap->rap_svr[a3] = *s++;
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}
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if ((rap->rap_sbf != 0x7ffff) || (!rap->rap_eos)) /* 19 bits */
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return 0;
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rap->rap_sdone = 1;
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s = (u_char *)rap->rap_svr + 11;
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if (((*s << 8) | *(s + 1)) == RA_ID_ROBUST) {
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s += 2;
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rap->rap_srport = (*s << 8) | *(s + 1);
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}
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ip = fin->fin_ip;
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swp = ip->ip_p;
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swa = ip->ip_src;
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swb = ip->ip_dst;
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ip->ip_p = IPPROTO_UDP;
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ip->ip_src = nat->nat_inip;
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ip->ip_dst = nat->nat_oip;
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bcopy((char *)fin, (char *)&fi, sizeof(fi));
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bzero((char *)tcp2, sizeof(*tcp2));
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TCP_OFF_A(tcp2, 5);
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fi.fin_state = NULL;
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fi.fin_nat = NULL;
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fi.fin_flx |= FI_IGNORE;
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fi.fin_dp = (char *)tcp2;
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fi.fin_fr = &raudiofr;
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fi.fin_dlen = sizeof(*tcp2);
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fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
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tcp2->th_win = htons(8192);
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slen = ip->ip_len;
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ip->ip_len = fin->fin_hlen + sizeof(*tcp);
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if (((rap->rap_mode & RAP_M_UDP_ROBUST) == RAP_M_UDP_ROBUST) &&
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(rap->rap_srport != 0)) {
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dp = rap->rap_srport;
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sp = rap->rap_prport;
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tcp2->th_sport = htons(sp);
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tcp2->th_dport = htons(dp);
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fi.fin_data[0] = dp;
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fi.fin_data[1] = sp;
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fi.fin_out = 0;
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nat2 = nat_new(&fi, nat->nat_ptr, NULL,
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NAT_SLAVE|IPN_UDP | (sp ? 0 : SI_W_SPORT),
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NAT_OUTBOUND);
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if (nat2 != NULL) {
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(void) nat_proto(&fi, nat2, IPN_UDP);
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nat_update(&fi, nat2, nat2->nat_ptr);
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(void) fr_addstate(&fi, NULL, (sp ? 0 : SI_W_SPORT));
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if (fi.fin_state != NULL)
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fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
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}
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}
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if ((rap->rap_mode & RAP_M_UDP) == RAP_M_UDP) {
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sp = rap->rap_plport;
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tcp2->th_sport = htons(sp);
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tcp2->th_dport = 0; /* XXX - don't specify remote port */
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fi.fin_data[0] = sp;
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fi.fin_data[1] = 0;
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fi.fin_out = 1;
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nat2 = nat_new(&fi, nat->nat_ptr, NULL,
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NAT_SLAVE|IPN_UDP|SI_W_DPORT,
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NAT_OUTBOUND);
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if (nat2 != NULL) {
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(void) nat_proto(&fi, nat2, IPN_UDP);
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nat_update(&fi, nat2, nat2->nat_ptr);
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(void) fr_addstate(&fi, NULL, SI_W_DPORT);
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if (fi.fin_state != NULL)
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fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
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}
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}
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ip->ip_p = swp;
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ip->ip_len = slen;
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ip->ip_src = swa;
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ip->ip_dst = swb;
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return 0;
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}
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