1 /* $NetBSD: ip_raudio_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $ */
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 1.1.1.2 2012/07/22 13:45:33 darrenr Exp
9 */
10
11 #include <sys/cdefs.h>
12 __KERNEL_RCSID(1, "$NetBSD: ip_raudio_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $");
13
14 #define IPF_RAUDIO_PROXY
15
16
17 void ipf_p_raudio_main_load(void);
18 void ipf_p_raudio_main_unload(void);
19 int ipf_p_raudio_new(void *, fr_info_t *, ap_session_t *, nat_t *);
20 int ipf_p_raudio_in(void *, fr_info_t *, ap_session_t *, nat_t *);
21 int ipf_p_raudio_out(void *, fr_info_t *, ap_session_t *, nat_t *);
22
23 static frentry_t raudiofr;
24
25 int raudio_proxy_init = 0;
26
27
28 /*
29 * Real Audio application proxy initialization.
30 */
31 void
ipf_p_raudio_main_load(void)32 ipf_p_raudio_main_load(void)
33 {
34 bzero((char *)&raudiofr, sizeof(raudiofr));
35 raudiofr.fr_ref = 1;
36 raudiofr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
37 MUTEX_INIT(&raudiofr.fr_lock, "Real Audio proxy rule lock");
38 raudio_proxy_init = 1;
39 }
40
41
42 void
ipf_p_raudio_main_unload(void)43 ipf_p_raudio_main_unload(void)
44 {
45 if (raudio_proxy_init == 1) {
46 MUTEX_DESTROY(&raudiofr.fr_lock);
47 raudio_proxy_init = 0;
48 }
49 }
50
51
52 /*
53 * Setup for a new proxy to handle Real Audio.
54 */
55 int
ipf_p_raudio_new(void * arg,fr_info_t * fin,ap_session_t * aps,nat_t * nat)56 ipf_p_raudio_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
57 {
58 raudio_t *rap;
59
60 nat = nat; /* LINT */
61
62 if (fin->fin_v != 4)
63 return -1;
64
65 KMALLOCS(aps->aps_data, void *, sizeof(raudio_t));
66 if (aps->aps_data == NULL)
67 return -1;
68
69 bzero(aps->aps_data, sizeof(raudio_t));
70 rap = aps->aps_data;
71 aps->aps_psiz = sizeof(raudio_t);
72 rap->rap_mode = RAP_M_TCP; /* default is for TCP */
73 return 0;
74 }
75
76
77
78 int
ipf_p_raudio_out(void * arg,fr_info_t * fin,ap_session_t * aps,nat_t * nat)79 ipf_p_raudio_out(void *arg, fr_info_t *fin, ap_session_t *aps, 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
182 int
ipf_p_raudio_in(void * arg,fr_info_t * fin,ap_session_t * aps,nat_t * nat)183 ipf_p_raudio_in(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
184 {
185 unsigned char membuf[IPF_MAXPORTLEN + 1], *s;
186 tcphdr_t *tcp, tcph, *tcp2 = &tcph;
187 raudio_t *rap = aps->aps_data;
188 ipf_main_softc_t *softc;
189 ipf_nat_softc_t *softn;
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 softc = fin->fin_main_soft;
202 softn = softc->ipf_nat_soft;
203 /*
204 * Wait until we've seen the end of the start messages and even then
205 * only proceed further if we're using UDP. If they want to use TCP
206 * then data is sent back on the same channel that is already open.
207 */
208 if (rap->rap_sdone != 0)
209 return 0;
210
211 m = fin->fin_m;
212 tcp = (tcphdr_t *)fin->fin_dp;
213 off = (char *)tcp - (char *)fin->fin_ip;
214 off += (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
215
216 #ifdef __sgi
217 dlen = fin->fin_plen - off;
218 #else
219 dlen = MSGDSIZE(m) - off;
220 #endif
221 if (dlen <= 0)
222 return 0;
223
224 if (dlen > sizeof(membuf))
225 dlen = sizeof(membuf);
226
227 bzero((char *)membuf, sizeof(membuf));
228 COPYDATA(m, off, dlen, (char *)membuf);
229
230 seq = ntohl(tcp->th_seq);
231 /*
232 * Check to see if the data in this packet is of interest to us.
233 * We only care for the first 19 bytes coming back from the server.
234 */
235 if (rap->rap_sseq == 0) {
236 s = (u_char *)memstr("PNA", (char *)membuf, 3, dlen);
237 if (s == NULL)
238 return 0;
239 a1 = s - membuf;
240 dlen -= a1;
241 a1 = 0;
242 rap->rap_sseq = seq;
243 a2 = MIN(dlen, sizeof(rap->rap_svr));
244 } else if (seq <= rap->rap_sseq + sizeof(rap->rap_svr)) {
245 /*
246 * seq # which is the start of data and from that the offset
247 * into the buffer array.
248 */
249 a1 = seq - rap->rap_sseq;
250 a2 = MIN(dlen, sizeof(rap->rap_svr));
251 a2 -= a1;
252 s = membuf;
253 } else
254 return 0;
255
256 for (a3 = a1, a4 = a2; (a4 > 0) && (a3 < 19) && (a3 >= 0); a4--,a3++) {
257 rap->rap_sbf |= (1 << a3);
258 rap->rap_svr[a3] = *s++;
259 }
260
261 if ((rap->rap_sbf != 0x7ffff) || (!rap->rap_eos)) /* 19 bits */
262 return 0;
263 rap->rap_sdone = 1;
264
265 s = (u_char *)rap->rap_svr + 11;
266 if (((*s << 8) | *(s + 1)) == RA_ID_ROBUST) {
267 s += 2;
268 rap->rap_srport = (*s << 8) | *(s + 1);
269 }
270
271 ip = fin->fin_ip;
272 swp = ip->ip_p;
273 swa = ip->ip_src;
274 swb = ip->ip_dst;
275
276 ip->ip_p = IPPROTO_UDP;
277 ip->ip_src = nat->nat_ndstip;
278 ip->ip_dst = nat->nat_odstip;
279
280 bcopy((char *)fin, (char *)&fi, sizeof(fi));
281 bzero((char *)tcp2, sizeof(*tcp2));
282 TCP_OFF_A(tcp2, 5);
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 = htons(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 MUTEX_ENTER(&softn->ipf_nat_new);
302 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
303 NAT_SLAVE|IPN_UDP | (sp ? 0 : SI_W_SPORT),
304 NAT_OUTBOUND);
305 MUTEX_EXIT(&softn->ipf_nat_new);
306 if (nat2 != NULL) {
307 (void) ipf_nat_proto(&fi, nat2, IPN_UDP);
308 MUTEX_ENTER(&nat2->nat_lock);
309 ipf_nat_update(&fi, nat2);
310 MUTEX_EXIT(&nat2->nat_lock);
311
312 (void) ipf_state_add(softc, &fi, NULL,
313 (sp ? 0 : SI_W_SPORT));
314 }
315 }
316
317 if ((rap->rap_mode & RAP_M_UDP) == RAP_M_UDP) {
318 sp = rap->rap_plport;
319 tcp2->th_sport = htons(sp);
320 tcp2->th_dport = 0; /* XXX - don't specify remote port */
321 fi.fin_data[0] = sp;
322 fi.fin_data[1] = 0;
323 fi.fin_out = 1;
324 MUTEX_ENTER(&softn->ipf_nat_new);
325 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
326 NAT_SLAVE|IPN_UDP|SI_W_DPORT,
327 NAT_OUTBOUND);
328 MUTEX_EXIT(&softn->ipf_nat_new);
329 if (nat2 != NULL) {
330 (void) ipf_nat_proto(&fi, nat2, IPN_UDP);
331 MUTEX_ENTER(&nat2->nat_lock);
332 ipf_nat_update(&fi, nat2);
333 MUTEX_EXIT(&nat2->nat_lock);
334
335 (void) ipf_state_add(softc, &fi, NULL, SI_W_DPORT);
336 }
337 }
338
339 ip->ip_p = swp;
340 ip->ip_len = slen;
341 ip->ip_src = swa;
342 ip->ip_dst = swb;
343 return 0;
344 }
345