4 * Copyright (C) 2000-2003 by Darren Reed
6 * See the IPFILTER.LICENCE file for details on licencing.
8 * Simple DCE transparent proxy for MSN RPC.
10 * ******* NOTE: THIS PROXY DOES NOT DO ADDRESS TRANSLATION ********
12 * Id: ip_msnrpc_pxy.c,v 2.17.2.1 2005/02/04 10:22:55 darrenr Exp
15 #define IPF_MSNRPC_PROXY
17 #define IPF_MINMSNRPCLEN 24
18 #define IPF_MSNRPCSKIP (2 + 19 + 2 + 2 + 2 + 19 + 2 + 2)
21 typedef struct msnrpchdr {
22 u_char mrh_major; /* major # == 5 */
23 u_char mrh_minor; /* minor # == 0 */
27 u_short mrh_dlen; /* data size */
28 u_short mrh_alen; /* authentication length */
29 u_32_t mrh_cid; /* call identifier */
30 u_32_t mrh_hint; /* allocation hint */
31 u_short mrh_ctxt; /* presentation context hint */
32 u_char mrh_ccnt; /* cancel count */
36 int ippr_msnrpc_init __P((void));
37 void ippr_msnrpc_fini __P((void));
38 int ippr_msnrpc_new __P((fr_info_t *, ap_session_t *, nat_t *));
39 int ippr_msnrpc_out __P((fr_info_t *, ap_session_t *, nat_t *));
40 int ippr_msnrpc_in __P((fr_info_t *, ap_session_t *, nat_t *));
41 int ippr_msnrpc_check __P((ip_t *, msnrpchdr_t *));
43 static frentry_t msnfr;
45 int msn_proxy_init = 0;
48 * Initialize local structures.
50 int ippr_msnrpc_init()
52 bzero((char *)&msnfr, sizeof(msnfr));
54 msnfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
55 MUTEX_INIT(&msnfr.fr_lock, "MSN RPC proxy rule lock");
62 void ippr_msnrpc_fini()
64 if (msn_proxy_init == 1) {
65 MUTEX_DESTROY(&msnfr.fr_lock);
71 int ippr_msnrpc_new(fin, aps, nat)
78 KMALLOC(mri, msnrpcinfo_t *);
82 aps->aps_psiz = sizeof(msnrpcinfo_t);
84 bzero((char *)mri, sizeof(*mri));
85 mri->mri_cmd[0] = 0xff;
86 mri->mri_cmd[1] = 0xff;
91 int ippr_msnrpc_check(ip, mrh)
95 if (mrh->mrh_major != 5)
97 if (mrh->mrh_minor != 0)
99 if (mrh->mrh_alen != 0)
101 if (mrh->mrh_endian == 0x10) {
102 /* Both gateway and packet match endian */
103 if (mrh->mrh_dlen > ip->ip_len)
105 if (mrh->mrh_type == 0 || mrh->mrh_type == 2)
106 if (mrh->mrh_hint > ip->ip_len)
108 } else if (mrh->mrh_endian == 0x10000000) {
109 /* XXX - Endian mismatch - should be swapping! */
118 int ippr_msnrpc_out(fin, ip, aps, nat)
133 tcp = (tcphdr_t *)fin->fin_dp;
134 dlen = fin->fin_dlen - (TCP_OFF(tcp) << 2);
135 if (dlen < IPF_MINMSNRPCLEN)
138 mrh = (msnrpchdr_t *)((char *)tcp + (TCP_OFF(tcp) << 2));
139 if (ippr_msnrpc_check(ip, mrh))
144 switch (mrh->mrh_type)
146 case 0x0b : /* BIND */
147 case 0x00 : /* REQUEST */
149 case 0x0c : /* BIND ACK */
150 case 0x02 : /* RESPONSE */
154 mri->mri_cmd[1] = mrh->mrh_type;
159 int ippr_msnrpc_in(fin, ip, aps, nat)
165 tcphdr_t *tcp, tcph, *tcp2 = &tcph;
166 int dlen, sz, sz2, i;
176 tcp = (tcphdr_t *)fin->fin_dp;
177 dlen = fin->fin_dlen - (TCP_OFF(tcp) << 2);
178 if (dlen < IPF_MINMSNRPCLEN)
181 mrh = (msnrpchdr_t *)((char *)tcp + (TCP_OFF(tcp) << 2));
182 if (ippr_msnrpc_check(ip, mrh))
187 switch (mrh->mrh_type)
189 case 0x0c : /* BIND ACK */
190 if (mri->mri_cmd[1] != 0x0b)
193 case 0x02 : /* RESPONSE */
194 if (mri->mri_cmd[1] != 0x00)
197 case 0x0b : /* BIND */
198 case 0x00 : /* REQUEST */
202 mri->mri_cmd[0] = mrh->mrh_type;
203 dlen -= sizeof(*mrh);
206 * Only processes RESPONSE's
208 if (mrh->mrh_type != 0x02)
212 * Skip over some bytes...what are these really ?
216 s = (char *)(mrh + 1) + 20;
218 bcopy(s, (char *)&len, sizeof(len));
222 } else if (len == 2) {
231 bcopy(s, (char *)&sz, sizeof(sz));
233 bcopy(s, (char *)&sz2, sizeof(sz2));
243 sz -= IPF_MSNRPCSKIP;
245 dlen -= IPF_MSNRPCSKIP;
248 if (sz < 7 || dlen < 7)
250 bcopy(s, (char *)&len, sizeof(len));
263 bcopy(s, (char *)&len, sizeof(len));
274 bcopy(s, (char *)&mri->mri_rport, 2);
280 bcopy(s, (char *)&mri->mri_raddr, 4);
292 if (mri->mri_flags == 3) {
295 bcopy((char *)fin, (char *)&fi, sizeof(fi));
296 bzero((char *)tcp2, sizeof(*tcp2));
299 ip->ip_len = fin->fin_hlen + sizeof(*tcp2);
300 bcopy((char *)fin, (char *)&fi, sizeof(fi));
301 bzero((char *)tcp2, sizeof(*tcp2));
302 tcp2->th_win = htons(8192);
304 fi.fin_data[0] = htons(mri->mri_rport);
305 tcp2->th_sport = mri->mri_rport;
310 fi.fin_dlen = sizeof(*tcp2);
311 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
312 fi.fin_dp = (char *)tcp2;
313 fi.fin_fi.fi_daddr = ip->ip_dst.s_addr;
314 fi.fin_fi.fi_saddr = mri->mri_raddr.s_addr;
317 if (fr_stlookup(&fi, NULL, NULL)) {
318 RWLOCK_EXIT(&ipf_state);
320 (void) fr_addstate(&fi, NULL, SI_W_DPORT|SI_CLONE);
321 if (fi.fin_state != NULL)
322 fr_statederef(&fi, (ipstate_t **)&fi.fin_state);