Added support for libcurl's CURLOPT_RESOLVE.

c/client.c

@@ -434,7 +434,7 @@ int main(int argc, char **argv) {
     srand(getpid());
     {   /* Option parsing */
         int opt;
-        while ((opt = getopt(argc, argv, "A:k:o:i:Vsqvu:C:KT:I:R:S:")) != -1) {
+        while ((opt = getopt(argc, argv, "A:k:o:i:Vsqvu:C:KT:I:R:S:H:")) != -1) {
             switch (opt) {
             case 'A':           /* Authentication options for remote server */
                 {               /* Scan string as hostname=username:password */
@@ -519,6 +519,10 @@ int main(int argc, char **argv) {
                 /* Interface */
                 want_interface = strdup(optarg);
                 break;
+            case 'H':
+                /* Resolve Host */
+                resolve_host = strdup(optarg);
+                break;
             }
         }
     }
@@ -731,6 +735,7 @@ int main(int argc, char **argv) {
         printf("used %lld local, fetched %lld\n", local_used, http_down);
     free(cacert);
     free(want_interface);
+    free(resolve_host);
     free(referer);
     free(temp_file);
     curl_global_cleanup();

c/doc/zsync.1

@@ -61,6 +61,10 @@ Use the specified client-side certificate file when making https connections.
 \fB\-S\fR \fIsslkey\fP
 Use the specified client-side private key file when making https connections.
 .TP
+\fB\-H\fR \fIhost:port:ip\fP
+Use the curl --resolve option to map a hostname to a different IP instead of doing a dns lookup.
+Example curl usage: curl --resolve foo.example.com:443:127.0.0.1 https://foo.example.com:443/
+.TP
 \fB\-I\fR \fIinterface\fP
 Attempt to use this interface name, IP address or hostname as the source of http connections.
 .TP

c/http.c

@@ -64,6 +64,9 @@ char *want_interface = NULL;
 char *sslcert = NULL;
 char *sslkey = NULL;
 
+/* Should we tell curl to resolve a host to a particular ip? */
+char *resolve_host = NULL;
+
 /* Should we tell curl to ignore SSL peer verification? */
 int be_insecure = 0;
 
@@ -163,6 +166,21 @@ CURL *make_curl_handle() {
             fprintf(stderr, "--interface: %s\n", curl_easy_strerror(res));
         }
     }
+
+    /* Requires CURL ver 7.21.3 or newer. */
+    /* Equiv of --resolve in curl */
+    if(resolve_host) {
+        /* -H */
+        struct curl_slist *host = NULL;
+        host = curl_slist_append(NULL, resolve_host);
+        res = curl_easy_setopt( curl, CURLOPT_RESOLVE, host );
+        if( res != CURLE_OK ) {
+            /* Warn and continue. Let's try anyway even if this setopt fails */
+            fprintf(stderr, "--resolve: %s\n", curl_easy_strerror(res));
+            curl_easy_cleanup(curl);
+            return NULL;
+        }
+    }
 
     if(be_insecure) {
         /* -K */

c/http.h

@@ -21,6 +21,7 @@ extern char *referer;
 
 extern char *cacert;
 extern char *want_interface;
+extern char *resolve_host;
 extern char *sslcert;
 extern char *sslkey;
 extern int be_insecure;