/* $NetBSD: ip_raudio_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $ */ /* * Copyright (C) 2012 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. * * Id: ip_raudio_pxy.c,v 1.1.1.2 2012/07/22 13:45:33 darrenr Exp */ #include __KERNEL_RCSID(1, "$NetBSD: ip_raudio_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $"); #define IPF_RAUDIO_PROXY void ipf_p_raudio_main_load(void); void ipf_p_raudio_main_unload(void); int ipf_p_raudio_new(void *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_raudio_in(void *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_raudio_out(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(void) { 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(void) { 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(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(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(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; }