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-rw-r--r--src/nss.c298
1 files changed, 298 insertions, 0 deletions
diff --git a/src/nss.c b/src/nss.c
new file mode 100644
index 0000000..0515b2d
--- /dev/null
+++ b/src/nss.c
@@ -0,0 +1,298 @@
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <nss.h>
+
+#include "query.h"
+
+#define MAX_ENTRIES 16
+
+#ifdef NSS_IPV4_ONLY
+#define _nss_mdns_gethostbyname2_r _nss_mdns4_gethostbyname2_r
+#define _nss_mdns_gethostbyname_r _nss_mdns4_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r _nss_mdns4_gethostbyaddr_r
+#elif NSS_IPV6_ONLY
+#define _nss_mdns_gethostbyname2_r _nss_mdns6_gethostbyname2_r
+#define _nss_mdns_gethostbyname_r _nss_mdns6_gethostbyname_r
+#define _nss_mdns_gethostbyaddr_r _nss_mdns6_gethostbyaddr_r
+#endif
+
+struct userdata {
+ int count;
+ int data_len; /* only valid when doing reverse lookup */
+ union {
+ ipv4_address_t ipv4[MAX_ENTRIES];
+ ipv6_address_t ipv6[MAX_ENTRIES];
+ char *name[MAX_ENTRIES];
+ } data;
+};
+
+static void ipv4_callback(const ipv4_address_t *ipv4, void *userdata) {
+ struct userdata *u = userdata;
+ assert(ipv4 && userdata);
+
+ if (u->count >= MAX_ENTRIES)
+ return;
+
+ u->data.ipv4[u->count++] = *ipv4;
+ u->data_len += sizeof(ipv4_address_t);
+}
+
+static void ipv6_callback(const ipv6_address_t *ipv6, void *userdata) {
+ struct userdata *u = userdata;
+ assert(ipv6 && userdata);
+
+ if (u->count >= MAX_ENTRIES)
+ return;
+
+ u->data.ipv6[u->count++] = *ipv6;
+ u->data_len += sizeof(ipv6_address_t);
+}
+
+static void name_callback(const char*name, void *userdata) {
+ struct userdata *u = userdata;
+ assert(name && userdata);
+
+ if (u->count >= MAX_ENTRIES)
+ return;
+
+ u->data.name[u->count++] = strdup(name);
+ u->data_len += strlen(name)+1;
+}
+
+enum nss_status _nss_mdns_gethostbyname2_r(
+ const char *name,
+ int af,
+ struct hostent * result,
+ char *buffer,
+ size_t buflen,
+ int *errnop,
+ int *h_errnop) {
+
+ struct userdata u;
+ enum nss_status status = NSS_STATUS_UNAVAIL;
+ int fd = -1, r, i;
+ size_t address_length, l, index, astart;
+
+/* DEBUG_TRAP; */
+
+#ifdef NSS_IPV4_ONLY
+ if (af != AF_INET)
+#elif NSS_IPV6_ONLY
+ if (af != AF_INET6)
+#else
+ if (af != AF_INET && af != AF_INET6)
+#endif
+ {
+ *errnop = EINVAL;
+ *h_errnop = NO_RECOVERY;
+ goto finish;
+ }
+
+ address_length = af == AF_INET ? sizeof(ipv4_address_t) : sizeof(ipv6_address_t);
+ if (buflen <
+ sizeof(char*)+ /* alias names */
+ strlen(name)+1) { /* official name */
+
+ *errnop = ERANGE;
+ *h_errnop = NO_RECOVERY;
+ status = NSS_STATUS_TRYAGAIN;
+
+ goto finish;
+ }
+
+ if ((fd = mdns_open_socket()) < 0) {
+
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+ goto finish;
+ }
+
+ u.count = 0;
+ u.data_len = 0;
+
+ if ((r = mdns_query_name(fd, name, af == AF_INET ? ipv4_callback : NULL, af == AF_INET6 ? ipv6_callback : NULL, &u)) < 0) {
+ *errnop = ETIMEDOUT;
+ *h_errnop = HOST_NOT_FOUND;
+ goto finish;
+ }
+
+ /* Alias names */
+ *((char**) buffer) = NULL;
+ result->h_aliases = (char**) buffer;
+ index = sizeof(char*);
+
+ /* Official name */
+ strcpy(buffer+index, name);
+ result->h_name = buffer+index;
+ index += strlen(name)+1;
+
+ result->h_addrtype = af;
+ result->h_length = address_length;
+
+ /* Check if there's enough space for the addresses */
+ if (buflen < index+u.data_len+sizeof(char*)*(u.count+1)) {
+ *errnop = ERANGE;
+ *h_errnop = NO_RECOVERY;
+ status = NSS_STATUS_TRYAGAIN;
+ goto finish;
+ }
+
+ /* Addresses */
+ astart = index;
+ l = u.count*address_length;
+ memcpy(buffer+astart, &u.data, l);
+ index += l;
+
+ /* Address array */
+ for (i = 0; i < u.count; i++)
+ ((char**) (buffer+index))[i] = buffer+astart+address_length*i;
+ ((char**) (buffer+index))[i] = NULL;
+
+ result->h_addr_list = (char**) (buffer+index);
+
+ status = NSS_STATUS_SUCCESS;
+
+finish:
+ if (fd >= 0)
+ close(fd);
+
+ return status;
+}
+
+enum nss_status _nss_mdns_gethostbyname_r (
+ const char *name,
+ struct hostent *result,
+ char *buffer,
+ size_t buflen,
+ int *errnop,
+ int *h_errnop) {
+
+ return _nss_mdns_gethostbyname2_r(
+ name,
+#ifdef NSS_IPV6_ONLY
+ AF_INET6,
+#else
+ AF_INET,
+#endif
+ result,
+ buffer,
+ buflen,
+ errnop,
+ h_errnop);
+}
+
+enum nss_status _nss_mdns_gethostbyaddr_r(
+ const void* addr,
+ int len,
+ int af,
+ struct hostent *result,
+ char *buffer,
+ size_t buflen,
+ int *errnop,
+ int *h_errnop) {
+
+ *errnop = EINVAL;
+ *h_errnop = NO_RECOVERY;
+
+ struct userdata u;
+ enum nss_status status = NSS_STATUS_UNAVAIL;
+ int fd = -1, r;
+ size_t address_length, index, astart;
+
+ u.count = 0;
+ u.data_len = 0;
+
+ address_length = af == AF_INET ? sizeof(ipv4_address_t) : sizeof(ipv6_address_t);
+
+ if (len != (int) address_length ||
+#ifdef NSS_IPV4_ONLY
+ af != AF_INET
+#elif NSS_IPV6_ONLY
+ af != AF_INET6
+#else
+ (af != AF_INET && af != AF_INET6)
+#endif
+ ) {
+ *errnop = EINVAL;
+ *h_errnop = NO_RECOVERY;
+ goto finish;
+ }
+
+ if (buflen <
+ sizeof(char*)+ /* alias names */
+ address_length) { /* address */
+
+ *errnop = ERANGE;
+ *h_errnop = NO_RECOVERY;
+ status = NSS_STATUS_TRYAGAIN;
+
+ goto finish;
+ }
+
+ if ((fd = mdns_open_socket()) < 0) {
+
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+ goto finish;
+ }
+
+ if (af == AF_INET)
+ r = mdns_query_ipv4(fd, (ipv4_address_t*) addr, name_callback, &u);
+ else
+ r = mdns_query_ipv6(fd, (ipv6_address_t*) addr, name_callback, &u);
+
+ if (r < 0) {
+ *errnop = ETIMEDOUT;
+ *h_errnop = HOST_NOT_FOUND;
+ goto finish;
+ }
+
+ /* Alias names */
+ *((char**) buffer) = NULL;
+ result->h_aliases = (char**) buffer;
+ index = sizeof(char*);
+
+ assert(u.count > 0 && u.data.name[0]);
+ if (buflen <
+ strlen(u.data.name[0])+1+ /* official names */
+ sizeof(char*)+ /* alias names */
+ address_length+ /* address */
+ sizeof(void*)*2) { /* address list */
+
+ *errnop = ERANGE;
+ *h_errnop = NO_RECOVERY;
+ status = NSS_STATUS_TRYAGAIN;
+ goto finish;
+ }
+
+ /* Official name */
+ strcpy(buffer+index, u.data.name[0]);
+ result->h_name = buffer+index;
+ index += strlen(u.data.name[0])+1;
+
+ result->h_addrtype = af;
+ result->h_length = address_length;
+
+ /* Address */
+ astart = index;
+ memcpy(buffer+astart, addr, address_length);
+ index += address_length;
+
+ /* Address array */
+ ((char**) (buffer+index))[0] = buffer+astart;
+ ((char**) (buffer+index))[1] = NULL;
+ result->h_addr_list = (char**) (buffer+index);
+
+ status = NSS_STATUS_SUCCESS;
+
+finish:
+ if (fd >= 0)
+ close(fd);
+
+ return status;
+}
+
generated by cgit (git 2.34.1) at 2024-11-10 17:54:51 +0000