From 55e55ea986ef5fed595bb5a4203e8734d79f1474 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 25 Jul 2023 17:36:31 +0100
Subject: [PATCH] curl: Add resolve option

This allows you to force a particular IP address for the URL host
name.

(cherry picked from commit 4f0989cbf0e9eeb959879b1c82b52940f6c5c3cc)
---
 plugins/curl/curl.c                 | 12 ++++++++++++
 plugins/curl/curldefs.h             |  1 +
 plugins/curl/nbdkit-curl-plugin.pod |  7 +++++++
 plugins/curl/pool.c                 |  2 ++
 4 files changed, 22 insertions(+)

diff --git a/plugins/curl/curl.c b/plugins/curl/curl.c
index 91fa65fb..381433fd 100644
--- a/plugins/curl/curl.c
+++ b/plugins/curl/curl.c
@@ -78,6 +78,7 @@ const char *protocols = NULL;
 const char *proxy = NULL;
 char *proxy_password = NULL;
 const char *proxy_user = NULL;
+struct curl_slist *resolves = NULL;
 bool sslverify = true;
 const char *ssl_cipher_list = NULL;
 long ssl_version = CURL_SSLVERSION_DEFAULT;
@@ -112,6 +113,8 @@ curl_unload (void)
     curl_slist_free_all (headers);
   free (password);
   free (proxy_password);
+  if (resolves)
+    curl_slist_free_all (resolves);
   scripts_unload ();
   free_all_handles ();
   curl_global_cleanup ();
@@ -356,6 +359,14 @@ curl_config (const char *key, const char *value)
   else if (strcmp (key, "proxy-user") == 0)
     proxy_user = value;
 
+  else if (strcmp (key, "resolve") == 0) {
+    resolves = curl_slist_append (headers, value);
+    if (resolves == NULL) {
+      nbdkit_error ("curl_slist_append: %m");
+      return -1;
+    }
+  }
+
   else if (strcmp (key, "sslverify") == 0) {
     r = nbdkit_parse_bool (value);
     if (r == -1)
@@ -515,6 +526,7 @@ curl_config_complete (void)
   "proxy=<PROXY>              Set proxy URL.\n" \
   "proxy-password=<PASSWORD>  The proxy password.\n" \
   "proxy-user=<USER>          The proxy user.\n" \
+  "resolve=<HOST>:<PORT>:<ADDR> Custom host to IP address resolution.\n" \
   "sslverify=false            Do not verify SSL certificate of remote host.\n" \
   "ssl-cipher-list=C1:C2:..   Specify TLS/SSL cipher suites to be used.\n" \
   "ssl-version=<VERSION>      Specify preferred TLS/SSL version.\n" \
diff --git a/plugins/curl/curldefs.h b/plugins/curl/curldefs.h
index 815be2e1..613cfed7 100644
--- a/plugins/curl/curldefs.h
+++ b/plugins/curl/curldefs.h
@@ -74,6 +74,7 @@ extern const char *proxy_user;
 extern bool sslverify;
 extern const char *ssl_cipher_list;
 extern long ssl_version;
+extern struct curl_slist *resolves;
 extern const char *tls13_ciphers;
 extern bool tcp_keepalive;
 extern bool tcp_nodelay;
diff --git a/plugins/curl/nbdkit-curl-plugin.pod b/plugins/curl/nbdkit-curl-plugin.pod
index e12ca197..a7315047 100644
--- a/plugins/curl/nbdkit-curl-plugin.pod
+++ b/plugins/curl/nbdkit-curl-plugin.pod
@@ -289,6 +289,12 @@ Set the proxy.  See L<CURLOPT_PROXY(3)>.
 
 Set the proxy username and password.
 
+=item B<resolve=>HOSTB<:>PORTB<:>ADDRESS
+
+Provide custom host name to IP address resolution.  You can supply
+this option as many times as needed.  See L<CURLOPT_RESOLVE(3)> for
+the full details of this option.
+
 =item B<sslverify=false>
 
 Don't verify the SSL certificate of the remote host.
@@ -574,6 +580,7 @@ L<CURLOPT_FOLLOWLOCATION(3)>,
 L<CURLOPT_HTTPHEADER(3)>,
 L<CURLOPT_IPRESOLVE(3)>,
 L<CURLOPT_PROXY(3)>,
+L<CURLOPT_RESOLVE(3)>,
 L<CURLOPT_SSL_CIPHER_LIST(3)>,
 L<CURLOPT_SSLVERSION(3)>,
 L<CURLOPT_TCP_KEEPALIVE(3)>,
diff --git a/plugins/curl/pool.c b/plugins/curl/pool.c
index f0c3cb4f..a6e2f9f5 100644
--- a/plugins/curl/pool.c
+++ b/plugins/curl/pool.c
@@ -283,6 +283,8 @@ allocate_handle (void)
     curl_easy_setopt (ch->c, CURLOPT_SSL_VERIFYPEER, 0L);
     curl_easy_setopt (ch->c, CURLOPT_SSL_VERIFYHOST, 0L);
   }
+  if (resolves)
+    curl_easy_setopt (ch->c, CURLOPT_RESOLVE, resolves);
   if (ssl_version != CURL_SSLVERSION_DEFAULT)
     curl_easy_setopt (ch->c, CURLOPT_SSLVERSION, (long) ssl_version);
   if (ssl_cipher_list)
-- 
2.39.3