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-rw-r--r--src/shared/dns-domain.c34
-rw-r--r--src/shared/dns-domain.h2
-rw-r--r--src/test/test-dns-domain.c31
3 files changed, 67 insertions, 0 deletions
diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c
index 7af15e0098..423ccca9cc 100644
--- a/src/shared/dns-domain.c
+++ b/src/shared/dns-domain.c
@@ -715,3 +715,37 @@ int dns_name_single_label(const char *name) {
return r == 0 && *name == 0;
}
+
+/* Encode a domain name according to RFC 1035 Section 3.1 */
+int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len) {
+ uint8_t *label_length;
+ uint8_t *out;
+ int r;
+
+ assert_return(buffer, -EINVAL);
+ assert_return(domain, -EINVAL);
+ assert_return(domain[0], -EINVAL);
+
+ out = buffer;
+
+ do {
+ /* reserve a byte for label length */
+ if (len == 0)
+ return -ENOBUFS;
+ len--;
+ label_length = out;
+ out++;
+
+ /* convert and copy a single label */
+ r = dns_label_unescape(&domain, (char *) out, len);
+ if (r < 0)
+ return r;
+
+ /* fill label length, move forward */
+ *label_length = r;
+ out += r;
+ len -= r;
+ } while (r != 0);
+
+ return out - buffer;
+}
diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h
index 1f0d242c18..b214897440 100644
--- a/src/shared/dns-domain.h
+++ b/src/shared/dns-domain.h
@@ -67,3 +67,5 @@ int dns_name_address(const char *p, int *family, union in_addr_union *a);
int dns_name_root(const char *name);
int dns_name_single_label(const char *name);
+
+int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len);
diff --git a/src/test/test-dns-domain.c b/src/test/test-dns-domain.c
index d5778748a0..407c7d8ef7 100644
--- a/src/test/test-dns-domain.c
+++ b/src/test/test-dns-domain.c
@@ -52,6 +52,36 @@ static void test_dns_label_unescape(void) {
test_dns_label_unescape_one("foobar.", "foobar", 20, 6);
}
+static void test_dns_name_to_wire_format_one(const char *what, const char *expect, size_t buffer_sz, int ret) {
+ uint8_t buffer[buffer_sz];
+ int r;
+
+ r = dns_name_to_wire_format(what, buffer, buffer_sz);
+ assert_se(r == ret);
+
+ if (r < 0)
+ return;
+
+ assert_se(!memcmp(buffer, expect, r));
+}
+
+static void test_dns_name_to_wire_format(void) {
+ const char out1[] = { 3, 'f', 'o', 'o', 0 };
+ const char out2[] = { 5, 'h', 'a', 'l', 'l', 'o', 3, 'f', 'o', 'o', 3, 'b', 'a', 'r', 0 };
+ const char out3[] = { 4, ' ', 'f', 'o', 'o', 3, 'b', 'a', 'r', 0 };
+
+ test_dns_name_to_wire_format_one("", NULL, 0, -EINVAL);
+
+ test_dns_name_to_wire_format_one("foo", out1, sizeof(out1), sizeof(out1));
+ test_dns_name_to_wire_format_one("foo", out1, sizeof(out1) + 1, sizeof(out1));
+ test_dns_name_to_wire_format_one("foo", out1, sizeof(out1) - 1, -ENOBUFS);
+
+ test_dns_name_to_wire_format_one("hallo.foo.bar", out2, sizeof(out2), sizeof(out2));
+ test_dns_name_to_wire_format_one("hallo.foo..bar", NULL, 32, -EINVAL);
+
+ test_dns_name_to_wire_format_one("\\032foo.bar", out3, sizeof(out3), sizeof(out3));
+}
+
static void test_dns_label_unescape_suffix_one(const char *what, const char *expect1, const char *expect2, size_t buffer_sz, int ret1, int ret2) {
char buffer[buffer_sz];
const char *label;
@@ -300,6 +330,7 @@ int main(int argc, char *argv[]) {
test_dns_name_reverse();
test_dns_name_concat();
test_dns_name_is_valid();
+ test_dns_name_to_wire_format();
return 0;
}