xref: /third_party/cares/0001-ADD-OHOS-DNS-PROXY-BY-NETSYS.patch

diff --git a/src/lib/ares_init.c b/src/lib/ares_init.c
index e8902c6..3a5a5f5 100644
--- a/src/lib/ares_init.c
+++ b/src/lib/ares_init.c
@@ -58,6 +58,64 @@
 #undef WIN32  /* Redefined in MingW/MSVC headers */
 #endif
 
+
+#if OHOS_DNS_PROXY_BY_NETSYS
+#include <dlfcn.h>
+#include <stdio.h>
+
+#if DNS_CONFIG_DEBUG
+#ifndef DNS_CONFIG_PRINT
+#define DNS_CONFIG_PRINT(fmt, ...) printf("DNS " fmt "\n", ##__VA_ARGS__)
+#endif
+#else
+#define DNS_CONFIG_PRINT(fmt, ...)
+#endif
+
+#define DNS_SO_PATH "libnetsys_client.z.so"
+#define OHOS_GET_CONFIG_FUNC_NAME "NetSysGetResolvConf"
+#define MAX_SERVER_NUM 5
+#define MAX_SERVER_LENGTH 50
+
+struct resolv_config {
+  int32_t error;
+  int32_t timeout_ms;
+  uint32_t retry_count;
+  char nameservers[MAX_SERVER_NUM][MAX_SERVER_LENGTH + 1];
+};
+
+typedef int32_t (*GetConfig)(uint16_t netId, struct resolv_config *config);
+
+static void *open_dns_lib(void)
+{
+  static void *lib = NULL;
+  if (lib != NULL) {
+    return lib;
+  }
+  lib = dlopen(DNS_SO_PATH, RTLD_LAZY);
+  if (lib == NULL) {
+    DNS_CONFIG_PRINT("%s: dlopen %s failed: %s",
+      __func__, DNS_SO_PATH, dlerror());
+    return NULL;
+  }
+  return lib;
+}
+
+static void *load_from_dns_lib(const char *symbol)
+{
+  void *lib_handle = open_dns_lib();
+  if (lib_handle == NULL) {
+    return NULL;
+  }
+
+  void *sym_addr = dlsym(lib_handle, symbol);
+  if (sym_addr == NULL) {
+    DNS_CONFIG_PRINT("%s: loading symbol %s with dlsym failed: %s",
+      __func__, symbol, dlerror());
+  }
+  return sym_addr;
+}
+#endif
+
 static int init_by_options(ares_channel channel,
                            const struct ares_options *options,
                            int optmask);
@@ -1705,6 +1763,12 @@ static int init_by_resolv_conf(ares_channel channel)
     int error;
     int update_domains;
     const char *resolvconf_path;
+#if OHOS_DNS_PROXY_BY_NETSYS
+    int netid = 0;
+    int ret = 0;
+    int status_each = -1;
+    GetConfig func = NULL;
+#endif
 
     /* Don't read resolv.conf and friends if we don't have to */
     if (ARES_CONFIG_CHECK(channel))
@@ -1720,6 +1784,36 @@ static int init_by_resolv_conf(ares_channel channel)
       resolvconf_path = PATH_RESOLV_CONF;
     }
 
+#if OHOS_DNS_PROXY_BY_NETSYS
+    *(void **) &func = load_from_dns_lib(OHOS_GET_CONFIG_FUNC_NAME);
+    if (!func) {
+      DNS_CONFIG_PRINT("%s: loading %s failed, use %s as a fallback",
+        __func__, OHOS_GET_CONFIG_FUNC_NAME, DNS_RESOLV_CONF_PATH);
+      goto etc_resolv_conf;
+    }
+    struct resolv_config config = {0};
+    ret = func(netid, &config);
+    if (ret < 0) {
+      DNS_CONFIG_PRINT("__get_resolv_conf OHOS_GET_CONFIG_FUNC_NAME err %d\n", ret);
+      return ARES_ENONAME;
+    }
+
+    for (int i = 0; i < MAX_SERVER_NUM; ++i) {
+      if (config.nameservers[i] == NULL || config.nameservers[i][0] == 0) {
+        continue;
+      }
+      status_each = config_nameserver(&servers, &nservers, config.nameservers[i]);
+      if (status_each == ARES_SUCCESS) {
+        status = ARES_SUCCESS;
+      }
+    }
+
+    if (status == ARES_SUCCESS && nservers > 0) {
+      goto get_conf_ok;
+    }
+
+etc_resolv_conf:
+#endif
     fp = fopen(resolvconf_path, "r");
     if (fp) {
       while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
@@ -1866,7 +1960,9 @@ static int init_by_resolv_conf(ares_channel channel)
         ares_free(sortlist);
       return status;
     }
-
+#if OHOS_DNS_PROXY_BY_NETSYS
+get_conf_ok:
+#endif
   /* If we got any name server entries, fill them in. */
   if (servers)
     {