1 /* $FreeBSD$ */
2
3 /*
4 * Copyright (C) 2012 by Darren Reed.
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 *
8 * $Id: ip_raudio_pxy.c,v 1.40.2.4 2006/07/14 06:12:17 darrenr Exp $
9 */
10
11 #define IPF_RAUDIO_PROXY
12
13
14 void ipf_p_raudio_main_load __P((void));
15 void ipf_p_raudio_main_unload __P((void));
16 int ipf_p_raudio_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
17 int ipf_p_raudio_in __P((void *, fr_info_t *, ap_session_t *, nat_t *));
18 int ipf_p_raudio_out __P((void *, fr_info_t *, ap_session_t *, nat_t *));
19
20 static frentry_t raudiofr;
21
22 int raudio_proxy_init = 0;
23
24
25 /*
26 * Real Audio application proxy initialization.
27 */
28 void
ipf_p_raudio_main_load()29 ipf_p_raudio_main_load()
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
38
39 void
ipf_p_raudio_main_unload()40 ipf_p_raudio_main_unload()
41 {
42 if (raudio_proxy_init == 1) {
43 MUTEX_DESTROY(&raudiofr.fr_lock);
44 raudio_proxy_init = 0;
45 }
46 }
47
48
49 /*
50 * Setup for a new proxy to handle Real Audio.
51 */
52 int
ipf_p_raudio_new(arg,fin,aps,nat)53 ipf_p_raudio_new(arg, fin, aps, nat)
54 void *arg;
55 fr_info_t *fin;
56 ap_session_t *aps;
57 nat_t *nat;
58 {
59 raudio_t *rap;
60
61 nat = nat; /* LINT */
62
63 if (fin->fin_v != 4)
64 return -1;
65
66 KMALLOCS(aps->aps_data, void *, sizeof(raudio_t));
67 if (aps->aps_data == NULL)
68 return -1;
69
70 bzero(aps->aps_data, sizeof(raudio_t));
71 rap = aps->aps_data;
72 aps->aps_psiz = sizeof(raudio_t);
73 rap->rap_mode = RAP_M_TCP; /* default is for TCP */
74 return 0;
75 }
76
77
78
79 int
ipf_p_raudio_out(arg,fin,aps,nat)80 ipf_p_raudio_out(arg, fin, aps, nat)
81 void *arg;
82 fr_info_t *fin;
83 ap_session_t *aps;
84 nat_t *nat;
85 {
86 raudio_t *rap = aps->aps_data;
87 unsigned char membuf[512 + 1], *s;
88 u_short id = 0;
89 tcphdr_t *tcp;
90 int off, dlen;
91 int len = 0;
92 mb_t *m;
93
94 nat = nat; /* LINT */
95
96 /*
97 * If we've already processed the start messages, then nothing left
98 * for the proxy to do.
99 */
100 if (rap->rap_eos == 1)
101 return 0;
102
103 m = fin->fin_m;
104 tcp = (tcphdr_t *)fin->fin_dp;
105 off = (char *)tcp - (char *)fin->fin_ip;
106 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
107
108 dlen = MSGDSIZE(m) - off;
109 if (dlen <= 0)
110 return 0;
111
112 if (dlen > sizeof(membuf))
113 dlen = sizeof(membuf);
114
115 bzero((char *)membuf, sizeof(membuf));
116 COPYDATA(m, off, dlen, (char *)membuf);
117 /*
118 * In all the startup parsing, ensure that we don't go outside
119 * the packet buffer boundary.
120 */
121 /*
122 * Look for the start of connection "PNA" string if not seen yet.
123 */
124 if (rap->rap_seenpna == 0) {
125 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
126 if (s == NULL)
127 return 0;
128 s += 3;
129 rap->rap_seenpna = 1;
130 } else
131 s = membuf;
132
133 /*
134 * Directly after the PNA will be the version number of this
135 * connection.
136 */
137 if (rap->rap_seenpna == 1 && rap->rap_seenver == 0) {
138 if ((s + 1) - membuf < dlen) {
139 rap->rap_version = (*s << 8) | *(s + 1);
140 s += 2;
141 rap->rap_seenver = 1;
142 } else
143 return 0;
144 }
145
146 /*
147 * Now that we've been past the PNA and version number, we're into the
148 * startup messages block. This ends when a message with an ID of 0.
149 */
150 while ((rap->rap_eos == 0) && ((s + 1) - membuf < dlen)) {
151 if (rap->rap_gotid == 0) {
152 id = (*s << 8) | *(s + 1);
153 s += 2;
154 rap->rap_gotid = 1;
155 if (id == RA_ID_END) {
156 rap->rap_eos = 1;
157 break;
158 }
159 } else if (rap->rap_gotlen == 0) {
160 len = (*s << 8) | *(s + 1);
161 s += 2;
162 rap->rap_gotlen = 1;
163 }
164
165 if (rap->rap_gotid == 1 && rap->rap_gotlen == 1) {
166 if (id == RA_ID_UDP) {
167 rap->rap_mode &= ~RAP_M_TCP;
168 rap->rap_mode |= RAP_M_UDP;
169 rap->rap_plport = (*s << 8) | *(s + 1);
170 } else if (id == RA_ID_ROBUST) {
171 rap->rap_mode |= RAP_M_ROBUST;
172 rap->rap_prport = (*s << 8) | *(s + 1);
173 }
174 s += len;
175 rap->rap_gotlen = 0;
176 rap->rap_gotid = 0;
177 }
178 }
179 return 0;
180 }
181
182
183 int
ipf_p_raudio_in(arg,fin,aps,nat)184 ipf_p_raudio_in(arg, fin, aps, nat)
185 void *arg;
186 fr_info_t *fin;
187 ap_session_t *aps;
188 nat_t *nat;
189 {
190 unsigned char membuf[IPF_MAXPORTLEN + 1], *s;
191 tcphdr_t *tcp, tcph, *tcp2 = &tcph;
192 raudio_t *rap = aps->aps_data;
193 ipf_main_softc_t *softc;
194 ipf_nat_softc_t *softn;
195 struct in_addr swa, swb;
196 int off, dlen, slen;
197 int a1, a2, a3, a4;
198 u_short sp, dp;
199 fr_info_t fi;
200 tcp_seq seq;
201 nat_t *nat2;
202 u_char swp;
203 ip_t *ip;
204 mb_t *m;
205
206 softc = fin->fin_main_soft;
207 softn = softc->ipf_nat_soft;
208 /*
209 * Wait until we've seen the end of the start messages and even then
210 * only proceed further if we're using UDP. If they want to use TCP
211 * then data is sent back on the same channel that is already open.
212 */
213 if (rap->rap_sdone != 0)
214 return 0;
215
216 m = fin->fin_m;
217 tcp = (tcphdr_t *)fin->fin_dp;
218 off = (char *)tcp - (char *)fin->fin_ip;
219 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
220
221 dlen = MSGDSIZE(m) - off;
222 if (dlen <= 0)
223 return 0;
224
225 if (dlen > sizeof(membuf))
226 dlen = sizeof(membuf);
227
228 bzero((char *)membuf, sizeof(membuf));
229 COPYDATA(m, off, dlen, (char *)membuf);
230
231 seq = ntohl(tcp->th_seq);
232 /*
233 * Check to see if the data in this packet is of interest to us.
234 * We only care for the first 19 bytes coming back from the server.
235 */
236 if (rap->rap_sseq == 0) {
237 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
238 if (s == NULL)
239 return 0;
240 a1 = s - membuf;
241 dlen -= a1;
242 a1 = 0;
243 rap->rap_sseq = seq;
244 a2 = MIN(dlen, sizeof(rap->rap_svr));
245 } else if (seq <= rap->rap_sseq + sizeof(rap->rap_svr)) {
246 /*
247 * seq # which is the start of data and from that the offset
248 * into the buffer array.
249 */
250 a1 = seq - rap->rap_sseq;
251 a2 = MIN(dlen, sizeof(rap->rap_svr));
252 a2 -= a1;
253 s = membuf;
254 } else
255 return 0;
256
257 for (a3 = a1, a4 = a2; (a4 > 0) && (a3 < 19) && (a3 >= 0); a4--,a3++) {
258 rap->rap_sbf |= (1 << a3);
259 rap->rap_svr[a3] = *s++;
260 }
261
262 if ((rap->rap_sbf != 0x7ffff) || (!rap->rap_eos)) /* 19 bits */
263 return 0;
264 rap->rap_sdone = 1;
265
266 s = (u_char *)rap->rap_svr + 11;
267 if (((*s << 8) | *(s + 1)) == RA_ID_ROBUST) {
268 s += 2;
269 rap->rap_srport = (*s << 8) | *(s + 1);
270 }
271
272 ip = fin->fin_ip;
273 swp = ip->ip_p;
274 swa = ip->ip_src;
275 swb = ip->ip_dst;
276
277 ip->ip_p = IPPROTO_UDP;
278 ip->ip_src = nat->nat_ndstip;
279 ip->ip_dst = nat->nat_odstip;
280
281 bcopy((char *)fin, (char *)&fi, sizeof(fi));
282 bzero((char *)tcp2, sizeof(*tcp2));
283 TCP_OFF_A(tcp2, 5);
284 fi.fin_flx |= FI_IGNORE;
285 fi.fin_dp = (char *)tcp2;
286 fi.fin_fr = &raudiofr;
287 fi.fin_dlen = sizeof(*tcp2);
288 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
289 tcp2->th_win = htons(8192);
290 slen = ip->ip_len;
291 ip->ip_len = htons(fin->fin_hlen + sizeof(*tcp));
292
293 if (((rap->rap_mode & RAP_M_UDP_ROBUST) == RAP_M_UDP_ROBUST) &&
294 (rap->rap_srport != 0)) {
295 dp = rap->rap_srport;
296 sp = rap->rap_prport;
297 tcp2->th_sport = htons(sp);
298 tcp2->th_dport = htons(dp);
299 fi.fin_data[0] = dp;
300 fi.fin_data[1] = sp;
301 fi.fin_out = 0;
302 MUTEX_ENTER(&softn->ipf_nat_new);
303 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
304 NAT_SLAVE|IPN_UDP | (sp ? 0 : SI_W_SPORT),
305 NAT_OUTBOUND);
306 MUTEX_EXIT(&softn->ipf_nat_new);
307 if (nat2 != NULL) {
308 (void) ipf_nat_proto(&fi, nat2, IPN_UDP);
309 MUTEX_ENTER(&nat2->nat_lock);
310 ipf_nat_update(&fi, nat2);
311 MUTEX_EXIT(&nat2->nat_lock);
312
313 (void) ipf_state_add(softc, &fi, NULL,
314 (sp ? 0 : SI_W_SPORT));
315 }
316 }
317
318 if ((rap->rap_mode & RAP_M_UDP) == RAP_M_UDP) {
319 sp = rap->rap_plport;
320 tcp2->th_sport = htons(sp);
321 tcp2->th_dport = 0; /* XXX - don't specify remote port */
322 fi.fin_data[0] = sp;
323 fi.fin_data[1] = 0;
324 fi.fin_out = 1;
325 MUTEX_ENTER(&softn->ipf_nat_new);
326 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
327 NAT_SLAVE|IPN_UDP|SI_W_DPORT,
328 NAT_OUTBOUND);
329 MUTEX_EXIT(&softn->ipf_nat_new);
330 if (nat2 != NULL) {
331 (void) ipf_nat_proto(&fi, nat2, IPN_UDP);
332 MUTEX_ENTER(&nat2->nat_lock);
333 ipf_nat_update(&fi, nat2);
334 MUTEX_EXIT(&nat2->nat_lock);
335
336 (void) ipf_state_add(softc, &fi, NULL, SI_W_DPORT);
337 }
338 }
339
340 ip->ip_p = swp;
341 ip->ip_len = slen;
342 ip->ip_src = swa;
343 ip->ip_dst = swb;
344 return 0;
345 }
346