trunk/Src/wptDNSKeys.cpp

/* wptDNSKeys.cpp - Support for retrieving keys via DNS
 *      Copyright (C) 2006 Timo Schulz
 *
 * This file is part of WinPT.
 *
 * WinPT is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * WinPT is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with WinPT; if not, write to the Free Software Foundation, 
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <windows.h>
#include <windns.h>


/* typedef for the function signature. */
typedef DNS_STATUS (*dns_query_fnc) (LPSTR, WORD, DWORD, PIP4_ARRAY,
                                    PDNS_RECORD*, PVOID *);
/* function pointer. */
static dns_query_fnc dns_query = NULL;

/* hinstance handle to the DLL. */
static HINSTANCE dns_api = NULL;

/* 1 if the DNS api is not available. */
static int dns_failed = 0;


/*
DNS_STATUS WINAPI DnsQuery (
  LPSTR lpstrName, WORD wType,
  DWORD fOptions, PIP4_ARRAY aipServers,
  PDNS_RECORD *ppQueryResultsSet,
  PVOID *pReserved 
);
*/

struct pka_info_s {
    int ver;
    char *fpr;
    char *uri;
};
typedef struct pka_info_s *pka_info_t;


/* Initialize the DNS sub system. We do this via dynamic loading
   because older NT/9X systems do not have this API. */
static int
dns_init (void)
{
    if (dns_query)
        return 0;
    if (dns_failed)
        return -1;
    dns_api = LoadLibrary ("dnsapi");
    if (!dns_api) {
        dns_failed = 1;
        return -1;
    }
    dns_query = (dns_query_fnc)GetProcAddress (dns_api, "DnsQuery_A");
    if (!dns_query) {
        dns_failed = 1;
        return -1;
    }
    return 0;
}

/* Cleanup static structs. */
void
dns_cleanup (void)
{
    if (dns_api)
        FreeLibrary (dns_api);
    dns_api = NULL;
}


/* Release the memory of the @pka structure. */
void
dns_free_pka_record (pka_info_t pka)
{
    if (pka->fpr)
        free (pka->fpr);
    if (pka->uri)
        free (pka->uri);
    free (pka);
}


/* build a DNS name for the PKA lookup. */
static char*
email_get_pka_addr (const char *uid)
{
    const char *fmt = "._pka.";
    char *bo;
    char *pka;
    int pos=0;

    if ((bo=strchr (uid, '<')) && strchr (uid, '>'))
        uid += (bo-uid+1);
    if (!strchr (uid, '@'))
        return NULL;

    pka = (char*)calloc (1, strlen (uid)+strlen (fmt)+1);
    while (uid && *uid != '@')
        pka[pos++] = *uid++;
    uid++;
    strcat (pka, "._pka."); pos += strlen (fmt);
    while (uid && *uid && *uid != '>')
        pka[pos++] = *uid++;
    return pka;
}


/* Convert the returned data from the PKA (txt) record. */
pka_info_t
parse_pka_data (const char *data)
{
    enum pka_col_t { COL_VER=1, COL_FPR, COL_URI };
    pka_info_t pka;
    char *p;
    int pos = 1;

    if (strncmp (data, "v=pka1;", 8))
        return NULL;
    pka = (pka_info_t)calloc (1, sizeof *pka);
    p = strtok ((char*)data, ";");
    while (p != NULL) {
        switch (pos) {
        case COL_VER: 
            pka->ver = 1; 
            break;

        case COL_FPR: 
            pka->fpr = strdup (p+strlen ("fpr=")); 
            break;

        case COL_URI:  /* optional */
            pka->uri = strdup (p+strlen ("uri=")); 
            break;

        default:
            break;
        }
        pos++;
    }
    if (pos != 3) {
        dns_free_pka_record (pka);
        pka = NULL;
    }
        
    return pka;
}


/* Retrieve a PKA record from the DNS.
   @userid is used to extract the email address. */
int
dns_get_pka_record (const char *userid, pka_info_t *r_pka)
{
    char *addr;
    DNS_STATUS err;
    DNS_RECORD *rec;

    *r_pka = NULL;
    if (dns_init ())
        return -1;
    addr = email_get_pka_addr (userid);
    if (!addr)
        return -1;
    err = dns_query (addr, DNS_TYPE_TEXT, 0, NULL, &rec, NULL);
    if (err) {
        free (addr);
        return -1;
    }
    *r_pka = parse_pka_data (rec->Data.Txt.pStringArray[0]);

    //DnsRecordListFree (rec, DnsFreeRecordList);
    free (addr);
    return 0;
}
1	twoaday	248	/* wptDNSKeys.cpp - Support for retrieving keys via DNS
2			* Copyright (C) 2006 Timo Schulz
3			*
4			* This file is part of WinPT.
5			*
6			* WinPT is free software; you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation; either version 2 of the License, or
9			* (at your option) any later version.
10			*
11			* WinPT is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with WinPT; if not, write to the Free Software Foundation,
18			* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
19			*/
20
21			#include <windows.h>
22			#include <windns.h>
23
24
25			/* typedef for the function signature. */
26			typedef DNS_STATUS (*dns_query_fnc) (LPSTR, WORD, DWORD, PIP4_ARRAY,
27			PDNS_RECORD, PVOID );
28			/* function pointer. */
29			static dns_query_fnc dns_query = NULL;
30
31			/* hinstance handle to the DLL. */
32			static HINSTANCE dns_api = NULL;
33
34			/* 1 if the DNS api is not available. */
35			static int dns_failed = 0;
36
37
38			/*
39			DNS_STATUS WINAPI DnsQuery (
40			LPSTR lpstrName, WORD wType,
41			DWORD fOptions, PIP4_ARRAY aipServers,
42			PDNS_RECORD *ppQueryResultsSet,
43			PVOID *pReserved
44			);
45			*/
46
47			struct pka_info_s {
48			int ver;
49			char *fpr;
50			char *uri;
51			};
52			typedef struct pka_info_s *pka_info_t;
53
54
55			/* Initialize the DNS sub system. We do this via dynamic loading
56			because older NT/9X systems do not have this API. */
57			static int
58			dns_init (void)
59			{
60			if (dns_query)
61			return 0;
62			if (dns_failed)
63			return -1;
64			dns_api = LoadLibrary ("dnsapi");
65			if (!dns_api) {
66			dns_failed = 1;
67			return -1;
68			}
69			dns_query = (dns_query_fnc)GetProcAddress (dns_api, "DnsQuery_A");
70			if (!dns_query) {
71			dns_failed = 1;
72			return -1;
73			}
74			return 0;
75			}
76
77			/* Cleanup static structs. */
78			void
79			dns_cleanup (void)
80			{
81			if (dns_api)
82			FreeLibrary (dns_api);
83			dns_api = NULL;
84			}
85
86
87			/* Release the memory of the @pka structure. */
88			void
89			dns_free_pka_record (pka_info_t pka)
90			{
91			if (pka->fpr)
92			free (pka->fpr);
93			if (pka->uri)
94			free (pka->uri);
95			free (pka);
96			}
97
98
99
100			/* build a DNS name for the PKA lookup. */
101			static char*
102			email_get_pka_addr (const char *uid)
103			{
104			const char *fmt = "._pka.";
105			char *bo;
106			char *pka;
107			int pos=0;
108
109			if ((bo=strchr (uid, '<')) && strchr (uid, '>'))
110			uid += (bo-uid+1);
111			if (!strchr (uid, '@'))
112			return NULL;
113
114			pka = (char*)calloc (1, strlen (uid)+strlen (fmt)+1);
115			while (uid && *uid != '@')
116			pka[pos++] = *uid++;
117			uid++;
118			strcat (pka, "._pka."); pos += strlen (fmt);
119			while (uid && uid && uid != '>')
120			pka[pos++] = *uid++;
121			return pka;
122			}
123
124
125			/* Convert the returned data from the PKA (txt) record. */
126			pka_info_t
127			parse_pka_data (const char *data)
128			{
129			enum pka_col_t { COL_VER=1, COL_FPR, COL_URI };
130			pka_info_t pka;
131			char *p;
132			int pos = 1;
133
134			if (strncmp (data, "v=pka1;", 8))
135			return NULL;
136			pka = (pka_info_t)calloc (1, sizeof *pka);
137			p = strtok ((char*)data, ";");
138			while (p != NULL) {
139			switch (pos) {
140			case COL_VER:
141			pka->ver = 1;
142			break;
143
144			case COL_FPR:
145			pka->fpr = strdup (p+strlen ("fpr="));
146			break;
147
148			case COL_URI: /* optional */
149			pka->uri = strdup (p+strlen ("uri="));
150			break;
151
152			default:
153			break;
154			}
155			pos++;
156			}
157			if (pos != 3) {
158			dns_free_pka_record (pka);
159			pka = NULL;
160			}
161
162			return pka;
163			}
164
165
166			/* Retrieve a PKA record from the DNS.
167			@userid is used to extract the email address. */
168			int
169			dns_get_pka_record (const char userid, pka_info_t r_pka)
170			{
171			char *addr;
172			DNS_STATUS err;
173			DNS_RECORD *rec;
174
175			*r_pka = NULL;
176			if (dns_init ())
177			return -1;
178			addr = email_get_pka_addr (userid);
179			if (!addr)
180			return -1;
181			err = dns_query (addr, DNS_TYPE_TEXT, 0, NULL, &rec, NULL);
182			if (err) {
183			free (addr);
184			return -1;
185			}
186			*r_pka = parse_pka_data (rec->Data.Txt.pStringArray[0]);
187
188			//DnsRecordListFree (rec, DnsFreeRecordList);
189			free (addr);
190			return 0;
191			}