Remove DNS64 detection code from clatd.
This has been unused since Q, when the NAT64 prefix started being
detected and passed in by netd instead. Many things depend on the
prefix being correct, including clat BPF offload and DNS64
synthesis, and doing DNS64 detection in clatd provides no way to
make these work. Additionally, R now supports getting the NAT64
prefix via the RA, which makes DNS64 detection in clatd even less
useful.
This CL removes all the DNS64 detection code. The new code parses
the prefix in main.c, and if the prefix is not valid, refuses to
start.
This also lets us remove the -n <netid> parameter which was only
used for DNS64 detection.
It also removes a dependency on dnsproxyd_protocol_headers, which
should be depended on by as few parts of the system as possible.
Test: m
Bug: 144730808
Bug: 151895202
Test: IPv6-only wifi continues to work
Change-Id: I892f364d6cbfe76277686387e35c04d3d6eb5ecc
diff --git a/config.c b/config.c
index 1c1a1f7..db0abc8 100644
--- a/config.c
+++ b/config.c
@@ -30,7 +30,6 @@
#include "clatd.h"
#include "config.h"
-#include "dns64.h"
#include "getaddr.h"
#include "logging.h"
@@ -158,35 +157,6 @@
*/
int ipv6_prefix_equal(struct in6_addr *a1, struct in6_addr *a2) { return !memcmp(a1, a2, 8); }
-/* function: dns64_detection
- * does dns lookups to set the plat subnet or exits on failure, waits forever for a dns response
- * with a query backoff timer
- * net_id - (optional) netId to use, NETID_UNSET indicates use of default network
- */
-void dns64_detection(unsigned net_id) {
- int backoff_sleep, status;
- struct in6_addr tmp_ptr;
-
- backoff_sleep = 1;
-
- while (1) {
- status = plat_prefix(DNS64_DETECTION_HOSTNAME, net_id, &tmp_ptr);
- if (status > 0) {
- memcpy(&Global_Clatd_Config.plat_subnet, &tmp_ptr, sizeof(struct in6_addr));
- return;
- }
- logmsg(ANDROID_LOG_WARN, "dns64_detection -- error, sleeping for %d seconds", backoff_sleep);
- sleep(backoff_sleep);
- backoff_sleep *= 2;
- if (backoff_sleep >= 1800) {
- // Scale down to one DNS query per half hour. Unnecessary DNS queries waste power, and the
- // benefit is minimal (basically, only limited to the case where a network goes from IPv6-only
- // to IPv6 with NAT64).
- backoff_sleep = 1800;
- }
- }
-}
-
/* function: gen_random_iid
* picks a random interface ID that is checksum neutral with the IPv4 address and the NAT64 prefix
* myaddr - IPv6 address to write to
@@ -293,13 +263,9 @@
* failure, 1 on success
* file - filename to parse
* uplink_interface - interface to use to reach the internet and supplier of address space
- * plat_prefix - (optional) plat prefix to use, otherwise follow config file
- * net_id - (optional) netId to use, NETID_UNSET indicates use of default network
*/
-int read_config(const char *file, const char *uplink_interface, const char *plat_prefix,
- unsigned net_id) {
+int read_config(const char *file, const char *uplink_interface) {
cnode *root = config_node("", "");
- void *tmp_ptr = NULL;
unsigned flags;
if (!root) {
@@ -326,27 +292,6 @@
&Global_Clatd_Config.ipv4_local_prefixlen))
goto failed;
- if (plat_prefix) { // plat subnet is coming from the command line
- if (inet_pton(AF_INET6, plat_prefix, &Global_Clatd_Config.plat_subnet) <= 0) {
- logmsg(ANDROID_LOG_FATAL, "invalid IPv6 address specified for plat prefix: %s", plat_prefix);
- goto failed;
- }
- } else {
- tmp_ptr = (void *)config_item_str(root, "plat_from_dns64", "yes");
- if (!tmp_ptr || strcmp(tmp_ptr, "no") == 0) {
- free(tmp_ptr);
-
- if (!config_item_ip6(root, "plat_subnet", NULL, &Global_Clatd_Config.plat_subnet)) {
- logmsg(ANDROID_LOG_FATAL, "plat_from_dns64 disabled, but no plat_subnet specified");
- goto failed;
- }
- } else {
- free(tmp_ptr);
-
- dns64_detection(net_id);
- }
- }
-
if (!config_item_ip6(root, "ipv6_host_id", "::", &Global_Clatd_Config.ipv6_host_id)) goto failed;
/* In order to prevent multiple devices attempting to use the same clat address, never use a