1 /* $FreeBSD: stable/9/sys/contrib/ipfilter/netinet/ip_raudio_pxy.c 170268 2007-06-04 02:54:36Z darrenr $ */
2
3 /*
4 * $FreeBSD: stable/9/sys/contrib/ipfilter/netinet/ip_raudio_pxy.c 170268 2007-06-04 02:54:36Z darrenr $
5 * Copyright (C) 1998-2003 by Darren Reed
6 *
7 * See the IPFILTER.LICENCE file for details on licencing.
8 *
9 * $Id: ip_raudio_pxy.c,v 1.40.2.4 2006/07/14 06:12:17 darrenr Exp $
10 */
11
12 #define IPF_RAUDIO_PROXY
13
14
15 int ippr_raudio_init __P((void));
16 void ippr_raudio_fini __P((void));
17 int ippr_raudio_new __P((fr_info_t *, ap_session_t *, nat_t *));
18 int ippr_raudio_in __P((fr_info_t *, ap_session_t *, nat_t *));
19 int ippr_raudio_out __P((fr_info_t *, ap_session_t *, nat_t *));
20
21 static frentry_t raudiofr;
22
23 int raudio_proxy_init = 0;
24
25
26 /*
27 * Real Audio application proxy initialization.
28 */
ippr_raudio_init()29 int ippr_raudio_init()
30 {
31 bzero((char *)&raudiofr, sizeof(raudiofr));
32 raudiofr.fr_ref = 1;
33 raudiofr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
34 MUTEX_INIT(&raudiofr.fr_lock, "Real Audio proxy rule lock");
35 raudio_proxy_init = 1;
36
37 return 0;
38 }
39
40
ippr_raudio_fini()41 void ippr_raudio_fini()
42 {
43 if (raudio_proxy_init == 1) {
44 MUTEX_DESTROY(&raudiofr.fr_lock);
45 raudio_proxy_init = 0;
46 }
47 }
48
49
50 /*
51 * Setup for a new proxy to handle Real Audio.
52 */
ippr_raudio_new(fin,aps,nat)53 int ippr_raudio_new(fin, aps, nat)
54 fr_info_t *fin;
55 ap_session_t *aps;
56 nat_t *nat;
57 {
58 raudio_t *rap;
59
60 KMALLOCS(aps->aps_data, void *, sizeof(raudio_t));
61 if (aps->aps_data == NULL)
62 return -1;
63
64 fin = fin; /* LINT */
65 nat = nat; /* LINT */
66
67 bzero(aps->aps_data, sizeof(raudio_t));
68 rap = aps->aps_data;
69 aps->aps_psiz = sizeof(raudio_t);
70 rap->rap_mode = RAP_M_TCP; /* default is for TCP */
71 return 0;
72 }
73
74
75
ippr_raudio_out(fin,aps,nat)76 int ippr_raudio_out(fin, aps, nat)
77 fr_info_t *fin;
78 ap_session_t *aps;
79 nat_t *nat;
80 {
81 raudio_t *rap = aps->aps_data;
82 unsigned char membuf[512 + 1], *s;
83 u_short id = 0;
84 tcphdr_t *tcp;
85 int off, dlen;
86 int len = 0;
87 mb_t *m;
88
89 nat = nat; /* LINT */
90
91 /*
92 * If we've already processed the start messages, then nothing left
93 * for the proxy to do.
94 */
95 if (rap->rap_eos == 1)
96 return 0;
97
98 m = fin->fin_m;
99 tcp = (tcphdr_t *)fin->fin_dp;
100 off = (char *)tcp - (char *)fin->fin_ip;
101 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
102
103 #ifdef __sgi
104 dlen = fin->fin_plen - off;
105 #else
106 dlen = MSGDSIZE(m) - off;
107 #endif
108 if (dlen <= 0)
109 return 0;
110
111 if (dlen > sizeof(membuf))
112 dlen = sizeof(membuf);
113
114 bzero((char *)membuf, sizeof(membuf));
115 COPYDATA(m, off, dlen, (char *)membuf);
116 /*
117 * In all the startup parsing, ensure that we don't go outside
118 * the packet buffer boundary.
119 */
120 /*
121 * Look for the start of connection "PNA" string if not seen yet.
122 */
123 if (rap->rap_seenpna == 0) {
124 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
125 if (s == NULL)
126 return 0;
127 s += 3;
128 rap->rap_seenpna = 1;
129 } else
130 s = membuf;
131
132 /*
133 * Directly after the PNA will be the version number of this
134 * connection.
135 */
136 if (rap->rap_seenpna == 1 && rap->rap_seenver == 0) {
137 if ((s + 1) - membuf < dlen) {
138 rap->rap_version = (*s << 8) | *(s + 1);
139 s += 2;
140 rap->rap_seenver = 1;
141 } else
142 return 0;
143 }
144
145 /*
146 * Now that we've been past the PNA and version number, we're into the
147 * startup messages block. This ends when a message with an ID of 0.
148 */
149 while ((rap->rap_eos == 0) && ((s + 1) - membuf < dlen)) {
150 if (rap->rap_gotid == 0) {
151 id = (*s << 8) | *(s + 1);
152 s += 2;
153 rap->rap_gotid = 1;
154 if (id == RA_ID_END) {
155 rap->rap_eos = 1;
156 break;
157 }
158 } else if (rap->rap_gotlen == 0) {
159 len = (*s << 8) | *(s + 1);
160 s += 2;
161 rap->rap_gotlen = 1;
162 }
163
164 if (rap->rap_gotid == 1 && rap->rap_gotlen == 1) {
165 if (id == RA_ID_UDP) {
166 rap->rap_mode &= ~RAP_M_TCP;
167 rap->rap_mode |= RAP_M_UDP;
168 rap->rap_plport = (*s << 8) | *(s + 1);
169 } else if (id == RA_ID_ROBUST) {
170 rap->rap_mode |= RAP_M_ROBUST;
171 rap->rap_prport = (*s << 8) | *(s + 1);
172 }
173 s += len;
174 rap->rap_gotlen = 0;
175 rap->rap_gotid = 0;
176 }
177 }
178 return 0;
179 }
180
181
ippr_raudio_in(fin,aps,nat)182 int ippr_raudio_in(fin, aps, nat)
183 fr_info_t *fin;
184 ap_session_t *aps;
185 nat_t *nat;
186 {
187 unsigned char membuf[IPF_MAXPORTLEN + 1], *s;
188 tcphdr_t *tcp, tcph, *tcp2 = &tcph;
189 raudio_t *rap = aps->aps_data;
190 struct in_addr swa, swb;
191 int off, dlen, slen;
192 int a1, a2, a3, a4;
193 u_short sp, dp;
194 fr_info_t fi;
195 tcp_seq seq;
196 nat_t *nat2;
197 u_char swp;
198 ip_t *ip;
199 mb_t *m;
200
201 /*
202 * Wait until we've seen the end of the start messages and even then
203 * only proceed further if we're using UDP. If they want to use TCP
204 * then data is sent back on the same channel that is already open.
205 */
206 if (rap->rap_sdone != 0)
207 return 0;
208
209 m = fin->fin_m;
210 tcp = (tcphdr_t *)fin->fin_dp;
211 off = (char *)tcp - (char *)fin->fin_ip;
212 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
213
214 #ifdef __sgi
215 dlen = fin->fin_plen - off;
216 #else
217 dlen = MSGDSIZE(m) - off;
218 #endif
219 if (dlen <= 0)
220 return 0;
221
222 if (dlen > sizeof(membuf))
223 dlen = sizeof(membuf);
224
225 bzero((char *)membuf, sizeof(membuf));
226 COPYDATA(m, off, dlen, (char *)membuf);
227
228 seq = ntohl(tcp->th_seq);
229 /*
230 * Check to see if the data in this packet is of interest to us.
231 * We only care for the first 19 bytes coming back from the server.
232 */
233 if (rap->rap_sseq == 0) {
234 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
235 if (s == NULL)
236 return 0;
237 a1 = s - membuf;
238 dlen -= a1;
239 a1 = 0;
240 rap->rap_sseq = seq;
241 a2 = MIN(dlen, sizeof(rap->rap_svr));
242 } else if (seq <= rap->rap_sseq + sizeof(rap->rap_svr)) {
243 /*
244 * seq # which is the start of data and from that the offset
245 * into the buffer array.
246 */
247 a1 = seq - rap->rap_sseq;
248 a2 = MIN(dlen, sizeof(rap->rap_svr));
249 a2 -= a1;
250 s = membuf;
251 } else
252 return 0;
253
254 for (a3 = a1, a4 = a2; (a4 > 0) && (a3 < 19) && (a3 >= 0); a4--,a3++) {
255 rap->rap_sbf |= (1 << a3);
256 rap->rap_svr[a3] = *s++;
257 }
258
259 if ((rap->rap_sbf != 0x7ffff) || (!rap->rap_eos)) /* 19 bits */
260 return 0;
261 rap->rap_sdone = 1;
262
263 s = (u_char *)rap->rap_svr + 11;
264 if (((*s << 8) | *(s + 1)) == RA_ID_ROBUST) {
265 s += 2;
266 rap->rap_srport = (*s << 8) | *(s + 1);
267 }
268
269 ip = fin->fin_ip;
270 swp = ip->ip_p;
271 swa = ip->ip_src;
272 swb = ip->ip_dst;
273
274 ip->ip_p = IPPROTO_UDP;
275 ip->ip_src = nat->nat_inip;
276 ip->ip_dst = nat->nat_oip;
277
278 bcopy((char *)fin, (char *)&fi, sizeof(fi));
279 bzero((char *)tcp2, sizeof(*tcp2));
280 TCP_OFF_A(tcp2, 5);
281 fi.fin_state = NULL;
282 fi.fin_nat = NULL;
283 fi.fin_flx |= FI_IGNORE;
284 fi.fin_dp = (char *)tcp2;
285 fi.fin_fr = &raudiofr;
286 fi.fin_dlen = sizeof(*tcp2);
287 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
288 tcp2->th_win = htons(8192);
289 slen = ip->ip_len;
290 ip->ip_len = fin->fin_hlen + sizeof(*tcp);
291
292 if (((rap->rap_mode & RAP_M_UDP_ROBUST) == RAP_M_UDP_ROBUST) &&
293 (rap->rap_srport != 0)) {
294 dp = rap->rap_srport;
295 sp = rap->rap_prport;
296 tcp2->th_sport = htons(sp);
297 tcp2->th_dport = htons(dp);
298 fi.fin_data[0] = dp;
299 fi.fin_data[1] = sp;
300 fi.fin_out = 0;
301 nat2 = nat_new(&fi, nat->nat_ptr, NULL,
302 NAT_SLAVE|IPN_UDP | (sp ? 0 : SI_W_SPORT),
303 NAT_OUTBOUND);
304 if (nat2 != NULL) {
305 (void) nat_proto(&fi, nat2, IPN_UDP);
306 nat_update(&fi, nat2, nat2->nat_ptr);
307
308 (void) fr_addstate(&fi, NULL, (sp ? 0 : SI_W_SPORT));
309 if (fi.fin_state != NULL)
310 fr_statederef((ipstate_t **)&fi.fin_state);
311 }
312 }
313
314 if ((rap->rap_mode & RAP_M_UDP) == RAP_M_UDP) {
315 sp = rap->rap_plport;
316 tcp2->th_sport = htons(sp);
317 tcp2->th_dport = 0; /* XXX - don't specify remote port */
318 fi.fin_data[0] = sp;
319 fi.fin_data[1] = 0;
320 fi.fin_out = 1;
321 nat2 = nat_new(&fi, nat->nat_ptr, NULL,
322 NAT_SLAVE|IPN_UDP|SI_W_DPORT,
323 NAT_OUTBOUND);
324 if (nat2 != NULL) {
325 (void) nat_proto(&fi, nat2, IPN_UDP);
326 nat_update(&fi, nat2, nat2->nat_ptr);
327
328 (void) fr_addstate(&fi, NULL, SI_W_DPORT);
329 if (fi.fin_state != NULL)
330 fr_statederef((ipstate_t **)&fi.fin_state);
331 }
332 }
333
334 ip->ip_p = swp;
335 ip->ip_len = slen;
336 ip->ip_src = swa;
337 ip->ip_dst = swb;
338 return 0;
339 }
340