the DNS record type that is being sought
The output from the program is written to stdout. It is supposed to be in
-exactly the same format as a traditional namserver response (see RFC 1035) so
+exactly the same format as a traditional nameserver response (see RFC 1035) so
that Exim can process it as normal. At present, no compression is used.
Error messages are written to stderr.
Any DNS record line in a zone file can be prefixed with "DELAY=" and
a number of milliseconds (followed by one space).
-Any DNS record line in a zone file can be prefixed with "DNSSEC ";
+Any DNS record line can be prefixed with "DNSSEC ";
if all the records found by a lookup are marked
-as such then the response will have the "AD" bit set.
+as such then the response will have the "AD" bit set.
-Any DNS record line in a zone file can be prefixed with "AA "
+Any DNS record line can be prefixed with "NXDOMAIN ";
+The record will be ignored (but the prefix set still applied);
+This lets us return a DNSSEC NXDOMAIN (=> HOST_NOT_FOUND).
+
+Any DNS record line can be prefixed with "AA "
if all the records found by a lookup are marked
as such then the response will have the "AA" bit set.
+Any DNS record line in a zone file can be prefixed with "TTL=" and
+a number of seconds (followed by one space).
+
*/
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <arpa/nameser.h>
+#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/time.h>
#include <dirent.h>
+#include <unistd.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
#define FALSE 0
#define TRUE 1
#define Ustrlen(s) (int)strlen(CCS(s))
#define Ustrncmp(s,t,n) strncmp(CCS(s),CCS(t),n)
#define Ustrncpy(s,t,n) strncpy(CS(s),CCS(t),n)
+#define Ustrtok(s,t) (uschar*)strtok(CS(s),CCS(t))
typedef struct zoneitem {
uschar *zone;
int value;
} tlist;
+#define DEFAULT_TTL 3600U
+
/* On some (older?) operating systems, the standard ns_t_xxx definitions are
not available, and only the older T_xxx ones exist in nameser.h. If ns_t_a is
not defined, assume we are in this state. A really old system might not even
qtypelen the length of qtype
pkptr points to the output buffer pointer; this is updated
countptr points to the record count; this is updated
- dnssec points to the AD flag indicator; this updated
- aa points to the AA flag indicator; this updated
+ dnssec_p points to the AD flag indicator; this is updated
+ aa_p points to the AA flag indicator; this is updated
Returns: 0 on success, else HOST_NOT_FOUND or NO_DATA or NO_RECOVERY or
PASS_ON - the latter if a "PASS ON NOT FOUND" line is seen
static int
find_records(FILE *f, uschar *zone, uschar *domain, uschar *qtype,
- int qtypelen, uschar **pkptr, int *countptr, BOOL * dnssec, BOOL * aa)
+ int qtypelen, uschar **pkptr, int *countptr, BOOL * dnssec_p, BOOL * aa_p)
{
int yield = HOST_NOT_FOUND;
int domainlen = Ustrlen(domain);
uschar rrdomain[256];
uschar RRdomain[256];
-/* Decode the required type */
+/* Decode the required type */
for (typeptr = type_list; typeptr->name != NULL; typeptr++)
{ if (Ustrcmp(typeptr->name, qtype) == 0) break; }
if (typeptr->name == NULL)
rrdomain[0] = 0; /* No previous domain */
(void)fseek(f, 0, SEEK_SET); /* Start again at the beginning */
-*dnssec = TRUE; /* cancelled by first nonsecure rec found */
-*aa = TRUE; /* cancelled by first non-authoritive record */
-
/* Scan for RRs */
while (fgets(CS buffer, sizeof(buffer), f) != NULL)
int qtlen = qtypelen;
BOOL rr_sec = FALSE;
BOOL rr_aa = FALSE;
+ BOOL rr_ignore = FALSE;
int delay = 0;
+ uint ttl = DEFAULT_TTL;
p = buffer;
while (isspace(*p)) p++;
p = buffer;
for (;;)
{
- if (Ustrncmp(p, US"DNSSEC ", 7) == 0) /* tagged as secure */
+ if (Ustrncmp(p, US"DNSSEC ", 7) == 0) /* tagged as secure */
{
rr_sec = TRUE;
p += 7;
}
- else if (Ustrncmp(p, US"AA ", 3) == 0) /* tagged as authoritive */
+ if (Ustrncmp(p, US"NXDOMAIN ", 9) == 0) /* ignore record content */
+ {
+ rr_ignore = TRUE;
+ p += 9;
+ }
+ else if (Ustrncmp(p, US"AA ", 3) == 0) /* tagged as authoritative */
{
rr_aa = TRUE;
p += 3;
}
- else if (Ustrncmp(p, US"DELAY=", 6) == 0) /* delay before response */
+ else if (Ustrncmp(p, US"DELAY=", 6) == 0) /* delay before response */
{
for (p += 6; *p >= '0' && *p <= '9'; p++) delay = delay*10 + *p - '0';
if (isspace(*p)) p++;
}
+ else if (Ustrncmp(p, US"TTL=", 4) == 0) /* TTL for record */
+ {
+ ttl = 0;
+ for (p += 4; *p >= '0' && *p <= '9'; p++) ttl = ttl*10 + *p - '0';
+ if (isspace(*p)) p++;
+ }
else
break;
}
/* The domain matches */
- if (yield == HOST_NOT_FOUND) yield = NO_DATA;
+ if (yield == HOST_NOT_FOUND)
+ {
+ yield = NO_DATA;
+ if (dnssec_p) *dnssec_p = TRUE; /* cancelled by first nonsecure rec found */
+ if (aa_p) *aa_p = TRUE; /* cancelled by first non-aa rec found */
+ }
/* Compare RR types; a CNAME record is always returned */
else if (Ustrncmp(p, qtype, qtypelen) != 0 || !isspace(p[qtypelen])) continue;
/* Found a relevant record */
-
if (delay)
millisleep(delay);
- if (!rr_sec)
- *dnssec = FALSE; /* cancel AD return */
+ if (dnssec_p && !rr_sec)
+ *dnssec_p = FALSE; /* cancel AD return */
- if (!rr_aa)
- *aa = FALSE; /* cancel AA return */
+ if (aa_p && !rr_aa)
+ *aa_p = FALSE; /* cancel AA return */
+
+ if (rr_ignore) continue;
yield = 0;
*countptr = *countptr + 1;
*pk++ = 0;
*pk++ = 1; /* class = IN */
- pk += 4; /* TTL field; don't care */
+ *pk++ = (ttl >>24) & 255;
+ *pk++ = (ttl >>16) & 255;
+ *pk++ = (ttl >> 8) & 255;
+ *pk++ = ttl & 255;
rdlptr = pk; /* remember rdlength field */
pk += 2;
switch (tvalue)
{
case ns_t_soa:
- p = strtok(p, " ");
- ep = p + strlen(p);
+ p = Ustrtok(p, " ");
+ ep = p + Ustrlen(p);
if (ep[-1] != '.') sprintf(CS ep, "%s.", zone);
- pk = packname(p, pk); /* primary ns */
- p = strtok(NULL, " ");
- pk = packname(p , pk); /* responsible mailbox */
- *(p += strlen(p)) = ' ';
+ pk = packname(p, pk); /* primary ns */
+ p = Ustrtok(NULL, " ");
+ pk = packname(p , pk); /* responsible mailbox */
+ *(p += Ustrlen(p)) = ' ';
while (isspace(*p)) p++;
- pk = longfield(&p, pk); /* serial */
- pk = longfield(&p, pk); /* refresh */
- pk = longfield(&p, pk); /* retry */
- pk = longfield(&p, pk); /* expire */
- pk = longfield(&p, pk); /* minimum */
+ pk = longfield(&p, pk); /* serial */
+ pk = longfield(&p, pk); /* refresh */
+ pk = longfield(&p, pk); /* retry */
+ pk = longfield(&p, pk); /* expire */
+ pk = longfield(&p, pk); /* minimum */
break;
case ns_t_a:
- for (i = 0; i < 4; i++)
- {
- value = 0;
- while (isdigit(*p)) value = value*10 + *p++ - '0';
- *pk++ = value;
- p++;
- }
+ inet_pton(AF_INET, CCS p, pk); /* FIXME: error checking */
+ pk += 4;
break;
- /* The only occurrence of a double colon is for ::1 */
case ns_t_aaaa:
- if (Ustrcmp(p, "::1") == 0)
- {
- memset(pk, 0, 15);
- pk += 15;
- *pk++ = 1;
- }
- else for (i = 0; i < 8; i++)
- {
- value = 0;
- while (isxdigit(*p))
- {
- value = value * 16 + toupper(*p) - (isdigit(*p)? '0' : '7');
- p++;
- }
- *pk++ = (value >> 8) & 255;
- *pk++ = value & 255;
- p++;
- }
+ inet_pton(AF_INET6, CCS p, pk); /* FIXME: error checking */
+ pk += 16;
break;
case ns_t_mx:
break;
case ns_t_tlsa:
- pk = bytefield(&p, pk); /* usage */
- pk = bytefield(&p, pk); /* selector */
- pk = bytefield(&p, pk); /* match type */
+ pk = bytefield(&p, pk); /* usage */
+ pk = bytefield(&p, pk); /* selector */
+ pk = bytefield(&p, pk); /* match type */
while (isxdigit(*p))
{
value = toupper(*p) - (isdigit(*p) ? '0' : '7') << 4;
if (isxdigit(*++p))
- {
- value |= toupper(*p) - (isdigit(*p) ? '0' : '7');
- p++;
- }
+ {
+ value |= toupper(*p) - (isdigit(*p) ? '0' : '7');
+ p++;
+ }
*pk++ = value & 255;
}
case ns_t_srv:
for (i = 0; i < 3; i++)
- {
- value = 0;
- while (isdigit(*p)) value = value*10 + *p++ - '0';
- while (isspace(*p)) p++;
- *pk++ = (value >> 8) & 255;
- *pk++ = value & 255;
- }
+ {
+ value = 0;
+ while (isdigit(*p)) value = value*10 + *p++ - '0';
+ while (isspace(*p)) p++;
+ *pk++ = (value >> 8) & 255;
+ *pk++ = value & 255;
+ }
/* Fall through */
{
}
+
+/*************************************************
+* Special-purpose domains *
+*************************************************/
+
+static int
+special_manyhome(uschar * packet, uschar * domain)
+{
+uschar *pk = packet + 12;
+uschar *rdlptr;
+int i, j;
+
+memset(packet, 0, 12);
+
+for (i = 104; i <= 111; i++) for (j = 0; j <= 255; j++)
+ {
+ pk = packname(domain, pk);
+ *pk++ = (ns_t_a >> 8) & 255;
+ *pk++ = (ns_t_a) & 255;
+ *pk++ = 0;
+ *pk++ = 1; /* class = IN */
+ pk += 4; /* TTL field; don't care */
+ rdlptr = pk; /* remember rdlength field */
+ pk += 2;
+
+ *pk++ = 10; *pk++ = 250; *pk++ = i; *pk++ = j;
+
+ rdlptr[0] = ((pk - rdlptr - 2) >> 8) & 255;
+ rdlptr[1] = (pk - rdlptr - 2) & 255;
+ }
+
+packet[6] = (2048 >> 8) & 255;
+packet[7] = 2048 & 255;
+packet[10] = 0;
+packet[11] = 0;
+
+(void)fwrite(packet, 1, pk - packet, stdout);
+return 0;
+}
+
+static int
+special_again(uschar * packet, uschar * domain)
+{
+int delay = atoi(CCS domain); /* digits at the start of the name */
+if (delay > 0) sleep(delay);
+return TRY_AGAIN;
+}
+
+
/*************************************************
* Entry point and main program *
*************************************************/
uschar buffer[256];
uschar qtype[12];
uschar packet[2048 * 32 + 32];
+HEADER *header = (HEADER *)packet;
uschar *pk = packet;
-BOOL dnssec;
-BOOL aa;
+BOOL dnssec = FALSE;
+BOOL aa = FALSE;
signal(SIGALRM, alarmfn);
(void)sprintf(CS buffer, "%s/dnszones", argv[1]);
-d = opendir(CCS buffer);
-if (d == NULL)
+if (!(d = opendir(CCS buffer)))
{
fprintf(stderr, "fakens: failed to opendir %s: %s\n", buffer,
strerror(errno));
return NO_RECOVERY;
}
-while ((de = readdir(d)) != NULL)
+while ((de = readdir(d)))
{
uschar *name = US de->d_name;
if (Ustrncmp(name, "qualify.", 8) == 0)
for (i = 0; i < domlen; i++) domain[i] = tolower(domain[i]);
if (Ustrcmp(domain, "manyhome.test.ex") == 0 && Ustrcmp(qtype, "A") == 0)
- {
- uschar *pk = packet + 12;
- uschar *rdlptr;
- int i, j;
-
- memset(packet, 0, 12);
-
- for (i = 104; i <= 111; i++) for (j = 0; j <= 255; j++)
- {
- pk = packname(domain, pk);
- *pk++ = (ns_t_a >> 8) & 255;
- *pk++ = (ns_t_a) & 255;
- *pk++ = 0;
- *pk++ = 1; /* class = IN */
- pk += 4; /* TTL field; don't care */
- rdlptr = pk; /* remember rdlength field */
- pk += 2;
-
- *pk++ = 10; *pk++ = 250; *pk++ = i; *pk++ = j;
-
- rdlptr[0] = ((pk - rdlptr - 2) >> 8) & 255;
- rdlptr[1] = (pk - rdlptr - 2) & 255;
- }
-
- packet[6] = (2048 >> 8) & 255;
- packet[7] = 2048 & 255;
- packet[10] = 0;
- packet[11] = 0;
-
- (void)fwrite(packet, 1, pk - packet, stdout);
- return 0;
- }
+ return special_manyhome(packet, domain);
+else if (domlen >= 14 && Ustrcmp(domain + domlen - 14, "test.again.dns") == 0)
+ return special_again(packet, domain);
+else if (domlen >= 13 && Ustrcmp(domain + domlen - 13, "test.fail.dns") == 0)
+ return NO_RECOVERY;
if (Ustrchr(domain, '.') == NULL && qualify != NULL &&
(void)sprintf(CS buffer, "%s/dnszones/%s", argv[1], zonefile);
-/* Initialize the start of the response packet. We don't have to fake up
-everything, because we know that Exim will look only at the answer and
-additional section parts. */
+/* Initialize the start of the response packet. */
memset(packet, 0, 12);
pk += 12;
/* Open the zone file. */
-f = fopen(CS buffer, "r");
-if (f == NULL)
+if (!(f = fopen(CS buffer, "r")))
{
fprintf(stderr, "fakens: failed to open %s: %s\n", buffer, strerror(errno));
return NO_RECOVERY;
}
+header->qr = 1; /* query */
+header->opcode = QUERY; /* standard query */
+header->tc = 0; /* no truncation */
+
/* Find the records we want, and add them to the result. */
count = 0;
yield = find_records(f, zone, domain, qtype, qtypelen, &pk, &count, &dnssec, &aa);
if (yield == NO_RECOVERY) goto END_OFF;
+header->ancount = htons(count);
+
+/* If the AA bit should be set (as indicated by the AA prefix in the zone file),
+we are expected to return some records in the authoritative section. Bind9: If
+there is data in the answer section, the authoritative section contains the NS
+records, otherwise it contains the SOA record. Mimic that.
+*/
-packet[6] = (count >> 8) & 255;
-packet[7] = count & 255;
+if (strcmp(qtype, "SOA") != 0 && strcmp(qtype, "NS") != 0)
+ if (count)
+ find_records(f, zone, zone[0] == '.' ? zone+1 : zone, US"NS", 2, &pk, &count, NULL, NULL);
+ else
+ find_records(f, zone, zone[0] == '.' ? zone+1 : zone, US"SOA", 3, &pk, &count, NULL, NULL);
+header->nscount = htons(count - ntohs(header->ancount));
/* There is no need to return any additional records because Exim no longer
(from release 4.61) makes any use of them. */
-
-packet[10] = 0;
-packet[11] = 0;
+header->arcount = 0;
if (dnssec)
- ((HEADER *)packet)->ad = 1;
+ header->ad = 1;
if (aa)
- ((HEADER *)packet)->aa = 1;
+ header->aa = 1;
/* Close the zone file, write the result, and return. */
projects / exim.git / blobdiff