*
* Copyright (c) 2007--2008 Martin Mares <mj@ucw.cz>
*
- * Can be freely distributed and used under the terms of the GNU GPL.
+ * Can be freely distributed and used under the terms of the GNU GPL v2+.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
*/
#include <string.h>
#include <stdlib.h>
+#include <stdio.h>
+
+#include "internal.h"
+#include "names.h"
+
+#ifdef PCI_USE_DNS
+
+/*
+ * Our definition of BYTE_ORDER confuses arpa/nameser_compat.h on
+ * Solaris so we must undef it before including arpa/nameser.h.
+ */
+#ifdef PCI_OS_SUNOS
+#undef BYTE_ORDER
+#endif
+
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
+#include <netdb.h>
-#include "internal.h"
-#include "names.h"
+/*
+ * Unfortunately, there are no portable functions for DNS RR parsing,
+ * so we will do the bit shuffling with our own bare hands.
+ */
+
+#define GET16(x) do { if (p+2 > end) goto err; x = (p[0] << 8) | p[1]; p += 2; } while (0)
+#define GET32(x) do { if (p+4 > end) goto err; x = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]; p += 4; } while (0)
+
+enum dns_section {
+ DNS_SEC_QUESTION,
+ DNS_SEC_ANSWER,
+ DNS_SEC_AUTHORITY,
+ DNS_SEC_ADDITIONAL,
+ DNS_NUM_SECTIONS
+};
+
+struct dns_state {
+ u16 counts[DNS_NUM_SECTIONS];
+ byte *sections[DNS_NUM_SECTIONS+1];
+ byte *sec_ptr, *sec_end;
+
+ /* Result of dns_parse_rr(): */
+ u16 rr_type;
+ u16 rr_class;
+ u32 rr_ttl;
+ u16 rr_len;
+ byte *rr_data;
+};
+
+static byte *
+dns_skip_name(byte *p, byte *end)
+{
+ while (p < end)
+ {
+ unsigned int x = *p++;
+ if (!x)
+ return p;
+ switch (x & 0xc0)
+ {
+ case 0: /* Uncompressed: x = length */
+ p += x;
+ break;
+ case 0xc0: /* Indirection: 1 byte more for offset */
+ p++;
+ return (p < end) ? p : NULL;
+ default: /* RFU */
+ return NULL;
+ }
+ }
+ return NULL;
+}
+
+static int
+dns_parse_packet(struct dns_state *s, byte *p, unsigned int plen)
+{
+ byte *end = p + plen;
+ unsigned int i, j, len;
+ unsigned int UNUSED x;
+
+#if 0
+ /* Dump the packet */
+ for (i=0; i<plen; i++)
+ {
+ if (!(i%16)) printf("%04x:", i);
+ printf(" %02x", p[i]);
+ if ((i%16)==15 || i==plen-1) putchar('\n');
+ }
+#endif
+
+ GET32(x); /* ID and flags are ignored */
+ for (i=0; i<DNS_NUM_SECTIONS; i++)
+ GET16(s->counts[i]);
+ for (i=0; i<DNS_NUM_SECTIONS; i++)
+ {
+ s->sections[i] = p;
+ for (j=0; j < s->counts[i]; j++)
+ {
+ p = dns_skip_name(p, end); /* Name */
+ if (!p)
+ goto err;
+ GET32(x); /* Type and class */
+ if (i != DNS_SEC_QUESTION)
+ {
+ GET32(x); /* TTL */
+ GET16(len); /* Length of data */
+ p += len;
+ if (p > end)
+ goto err;
+ }
+ }
+ }
+ s->sections[i] = p;
+ return 0;
+
+err:
+ return -1;
+}
+
+static void
+dns_init_section(struct dns_state *s, int i)
+{
+ s->sec_ptr = s->sections[i];
+ s->sec_end = s->sections[i+1];
+}
+
+static int
+dns_parse_rr(struct dns_state *s)
+{
+ byte *p = s->sec_ptr;
+ byte *end = s->sec_end;
+
+ if (p == end)
+ return 0;
+ p = dns_skip_name(p, end);
+ if (!p)
+ goto err;
+ GET16(s->rr_type);
+ GET16(s->rr_class);
+ GET32(s->rr_ttl);
+ GET16(s->rr_len);
+ s->rr_data = p;
+ s->sec_ptr = p + s->rr_len;
+ return 1;
+
+err:
+ return -1;
+}
char
*pci_id_net_lookup(struct pci_access *a, int cat, int id1, int id2, int id3, int id4)
{
- char name[256], dnsname[256], txt[256];
+ static int resolver_inited;
+ char name[256], dnsname[256], txt[256], *domain;
byte answer[4096];
const byte *data;
- int res, i, j, dlen;
- ns_msg m;
- ns_rr rr;
+ int res, j, dlen;
+ struct dns_state ds;
+
+ domain = pci_get_param(a, "net.domain");
+ if (!domain || !domain[0])
+ return NULL;
switch (cat)
{
default:
return NULL;
}
- sprintf(dnsname, "%s.%s", name, a->id_domain);
+ sprintf(dnsname, "%.100s.%.100s", name, domain);
a->debug("Resolving %s\n", dnsname);
- res_init();
+ if (!resolver_inited)
+ {
+ resolver_inited = 1;
+ res_init();
+ }
res = res_query(dnsname, ns_c_in, ns_t_txt, answer, sizeof(answer));
if (res < 0)
{
- a->debug("\tfailed, h_errno=%d\n", _res.res_h_errno);
+ a->debug("\tfailed, h_errno=%d\n", h_errno);
return NULL;
}
- if (ns_initparse(answer, res, &m) < 0)
+ if (dns_parse_packet(&ds, answer, res) < 0)
{
- a->debug("\tinitparse failed\n");
+ a->debug("\tMalformed DNS packet received\n");
return NULL;
}
- for (i=0; ns_parserr(&m, ns_s_an, i, &rr) >= 0; i++)
+ dns_init_section(&ds, DNS_SEC_ANSWER);
+ while (dns_parse_rr(&ds) > 0)
{
- a->debug("\tanswer %d (class %d, type %d)\n", i, ns_rr_class(rr), ns_rr_type(rr));
- if (ns_rr_class(rr) != ns_c_in || ns_rr_type(rr) != ns_t_txt)
- continue;
- data = ns_rr_rdata(rr);
- dlen = ns_rr_rdlen(rr);
+ if (ds.rr_class != ns_c_in || ds.rr_type != ns_t_txt)
+ {
+ a->debug("\tUnexpected RR in answer: class %d, type %d\n", ds.rr_class, ds.rr_type);
+ continue;
+ }
+ data = ds.rr_data;
+ dlen = ds.rr_len;
j = 0;
while (j < dlen && j+1+data[j] <= dlen)
{
memcpy(txt, &data[j+1], data[j]);
txt[data[j]] = 0;
j += 1+data[j];
- a->debug("\t\t%s\n", txt);
+ a->debug("\t\"%s\"\n", txt);
if (txt[0] == 'i' && txt[1] == '=')
return strdup(txt+2);
}
return NULL;
}
-void
-pci_set_net_domain(struct pci_access *a, char *name, int to_be_freed)
+#else
+
+char *pci_id_net_lookup(struct pci_access *a UNUSED, int cat UNUSED, int id1 UNUSED, int id2 UNUSED, int id3 UNUSED, int id4 UNUSED)
{
- if (a->free_id_domain)
- free(a->id_domain);
- a->id_domain = name;
- a->free_id_domain = to_be_freed;
+ return NULL;
}
+
+#endif