Merge branch 'ew/force-ipv4'

"git fetch" and friends that make network connections can now be
told to only use ipv4 (or ipv6).

* ew/force-ipv4:
  connect & http: support -4 and -6 switches for remote operations

13 files changed, 95 insertions, 0 deletions

diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 952dfdfef0..036edfb099 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -158,3 +158,11 @@ endif::git-pull[]
 	by default when it is attached to a terminal, unless -q
 	is specified. This flag forces progress status even if the
 	standard error stream is not directed to a terminal.
+
+-4::
+--ipv4::
+	Use IPv4 addresses only, ignoring IPv6 addresses.
+
+-6::
+--ipv6::
+	Use IPv6 addresses only, ignoring IPv4 addresses.
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 32482cec42..669a357c81 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -277,6 +277,13 @@ origin +master` to force a push to the `master` branch). See the
 	default is --verify, giving the hook a chance to prevent the
 	push.  With --no-verify, the hook is bypassed completely.
 
+-4::
+--ipv4::
+	Use IPv4 addresses only, ignoring IPv6 addresses.
+
+-6::
+--ipv6::
+	Use IPv6 addresses only, ignoring IPv4 addresses.
 
 include::urls-remotes.txt[]
 
diff --git a/builtin/clone.c b/builtin/clone.c
index bcba0805e1..b8c39aa701 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -47,6 +47,7 @@ static const char *real_git_dir;
 static char *option_upload_pack = "git-upload-pack";
 static int option_verbosity;
 static int option_progress = -1;
+static enum transport_family family;
 static struct string_list option_config;
 static struct string_list option_reference;
 static int option_dissociate;
@@ -92,6 +93,10 @@ static struct option builtin_clone_options[] = {
 		   N_("separate git dir from working tree")),
 	OPT_STRING_LIST('c', "config", &option_config, N_("key=value"),
 			N_("set config inside the new repository")),
+	OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
+			TRANSPORT_FAMILY_IPV4),
+	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
+			TRANSPORT_FAMILY_IPV6),
 	OPT_END()
 };
 
@@ -970,6 +975,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	remote = remote_get(option_origin);
 	transport = transport_get(remote, remote->url[0]);
 	transport_set_verbosity(transport, option_verbosity, option_progress);
+	transport->family = family;
 
 	path = get_repo_path(remote->url[0], &is_bundle);
 	is_local = option_local != 0 && path && !is_bundle;
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 8e742135f0..55919a9e4f 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -38,6 +38,7 @@ static int all, append, dry_run, force, keep, multiple, update_head_ok, verbosit
 static int progress = -1, recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
 static int tags = TAGS_DEFAULT, unshallow, update_shallow;
 static int max_children = 1;
+static enum transport_family family;
 static const char *depth;
 static const char *upload_pack;
 static struct strbuf default_rla = STRBUF_INIT;
@@ -127,6 +128,10 @@ static struct option builtin_fetch_options[] = {
 		 N_("accept refs that update .git/shallow")),
 	{ OPTION_CALLBACK, 0, "refmap", NULL, N_("refmap"),
 	  N_("specify fetch refmap"), PARSE_OPT_NONEG, parse_refmap_arg },
+	OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
+			TRANSPORT_FAMILY_IPV4),
+	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
+			TRANSPORT_FAMILY_IPV6),
 	OPT_END()
 };
 
@@ -864,6 +869,7 @@ static struct transport *prepare_transport(struct remote *remote)
 	struct transport *transport;
 	transport = transport_get(remote, NULL);
 	transport_set_verbosity(transport, verbosity, progress);
+	transport->family = family;
 	if (upload_pack)
 		set_option(transport, TRANS_OPT_UPLOADPACK, upload_pack);
 	if (keep)
diff --git a/builtin/push.c b/builtin/push.c
index 960ffc31e1..6e13b3c90a 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -23,6 +23,7 @@ static const char *receivepack;
 static int verbosity;
 static int progress = -1;
 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
+static enum transport_family family;
 
 static struct push_cas_option cas;
 
@@ -346,6 +347,7 @@ static int push_with_options(struct transport *transport, int flags)
 	unsigned int reject_reasons;
 
 	transport_set_verbosity(transport, verbosity, progress);
+	transport->family = family;
 
 	if (receivepack)
 		transport_set_option(transport,
@@ -565,6 +567,10 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		  0, "signed", &push_cert, "yes|no|if-asked", N_("GPG sign the push"),
 		  PARSE_OPT_OPTARG, option_parse_push_signed },
 		OPT_BIT(0, "atomic", &flags, N_("request atomic transaction on remote side"), TRANSPORT_PUSH_ATOMIC),
+		OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
+				TRANSPORT_FAMILY_IPV4),
+		OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
+				TRANSPORT_FAMILY_IPV6),
 		OPT_END()
 	};
 
diff --git a/connect.c b/connect.c
index fd7ffe1840..047863144f 100644
--- a/connect.c
+++ b/connect.c
@@ -357,6 +357,10 @@ static int git_tcp_connect_sock(char *host, int flags)
 		port = "<none>";
 
 	memset(&hints, 0, sizeof(hints));
+	if (flags & CONNECT_IPV4)
+		hints.ai_family = AF_INET;
+	else if (flags & CONNECT_IPV6)
+		hints.ai_family = AF_INET6;
 	hints.ai_socktype = SOCK_STREAM;
 	hints.ai_protocol = IPPROTO_TCP;
 
@@ -783,6 +787,10 @@ struct child_process *git_connect(int fd[2], const char *url,
 			}
 
 			argv_array_push(&conn->args, ssh);
+			if (flags & CONNECT_IPV4)
+				argv_array_push(&conn->args, "-4");
+			else if (flags & CONNECT_IPV6)
+				argv_array_push(&conn->args, "-6");
 			if (tortoiseplink)
 				argv_array_push(&conn->args, "-batch");
 			if (port) {
diff --git a/connect.h b/connect.h
index c41a6850f1..01f14cdf3f 100644
--- a/connect.h
+++ b/connect.h
@@ -3,6 +3,8 @@
 
 #define CONNECT_VERBOSE       (1u << 0)
 #define CONNECT_DIAG_URL      (1u << 1)
+#define CONNECT_IPV4          (1u << 2)
+#define CONNECT_IPV6          (1u << 3)
 extern struct child_process *git_connect(int fd[2], const char *url, const char *prog, int flags);
 extern int finish_connect(struct child_process *conn);
 extern int git_connection_is_socket(struct child_process *conn);
diff --git a/http.c b/http.c
index dfc53c1e25..f543b14278 100644
--- a/http.c
+++ b/http.c
@@ -11,6 +11,11 @@
 #include "gettext.h"
 #include "transport.h"
 
+#if LIBCURL_VERSION_NUM >= 0x070a08
+long int git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
+#else
+long int git_curl_ipresolve;
+#endif
 int active_requests;
 int http_is_verbose;
 size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
@@ -824,6 +829,10 @@ struct active_request_slot *get_active_slot(void)
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 	curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
 	curl_easy_setopt(slot->curl, CURLOPT_RANGE, NULL);
+
+#if LIBCURL_VERSION_NUM >= 0x070a08
+	curl_easy_setopt(slot->curl, CURLOPT_IPRESOLVE, git_curl_ipresolve);
+#endif
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPAUTH, http_auth_methods);
 #endif
diff --git a/http.h b/http.h
index f83cfa6868..4ef4bbda7d 100644
--- a/http.h
+++ b/http.h
@@ -107,6 +107,7 @@ extern void http_init(struct remote *remote, const char *url,
 		      int proactive_auth);
 extern void http_cleanup(void);
 
+extern long int git_curl_ipresolve;
 extern int active_requests;
 extern int http_is_verbose;
 extern size_t http_post_buffer;
diff --git a/remote-curl.c b/remote-curl.c
index c7048575fb..b33a1e4235 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -119,6 +119,19 @@ static int set_option(const char *name, const char *value)
 		else
 			return -1;
 		return 0;
+
+#if LIBCURL_VERSION_NUM >= 0x070a08
+	} else if (!strcmp(name, "family")) {
+		if (!strcmp(value, "ipv4"))
+			git_curl_ipresolve = CURL_IPRESOLVE_V4;
+		else if (!strcmp(value, "ipv6"))
+			git_curl_ipresolve = CURL_IPRESOLVE_V6;
+		else if (!strcmp(value, "all"))
+			git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
+		else
+			return -1;
+		return 0;
+#endif /* LIBCURL_VERSION_NUM >= 0x070a08 */
 	} else {
 		return 1 /* unsupported */;
 	}
diff --git a/transport-helper.c b/transport-helper.c
index a6bff8b308..b934183236 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -321,6 +321,21 @@ static void standard_options(struct transport *t)
 	if (n >= sizeof(buf))
 		die("impossibly large verbosity value");
 	set_helper_option(t, "verbosity", buf);
+
+	switch (t->family) {
+	case TRANSPORT_FAMILY_ALL:
+		/*
+		 * this is already the default,
+		 * do not break old remote helpers by setting "all" here
+		 */
+		break;
+	case TRANSPORT_FAMILY_IPV4:
+		set_helper_option(t, "family", "ipv4");
+		break;
+	case TRANSPORT_FAMILY_IPV6:
+		set_helper_option(t, "family", "ipv6");
+		break;
+	}
 }
 
 static int release_helper(struct transport *transport)
diff --git a/transport.c b/transport.c
index c92f8ae705..e20bb771fa 100644
--- a/transport.c
+++ b/transport.c
@@ -163,6 +163,12 @@ static int connect_setup(struct transport *transport, int for_push)
 	if (data->conn)
 		return 0;
 
+	switch (transport->family) {
+	case TRANSPORT_FAMILY_ALL: break;
+	case TRANSPORT_FAMILY_IPV4: flags |= CONNECT_IPV4; break;
+	case TRANSPORT_FAMILY_IPV6: flags |= CONNECT_IPV6; break;
+	}
+
 	data->conn = git_connect(data->fd, transport->url,
 				 for_push ? data->options.receivepack :
 				 data->options.uploadpack,
diff --git a/transport.h b/transport.h
index 8ebaaf2cae..c68140892c 100644
--- a/transport.h
+++ b/transport.h
@@ -18,6 +18,12 @@ struct git_transport_options {
 	struct push_cas_option *cas;
 };
 
+enum transport_family {
+	TRANSPORT_FAMILY_ALL = 0,
+	TRANSPORT_FAMILY_IPV4,
+	TRANSPORT_FAMILY_IPV6
+};
+
 struct transport {
 	struct remote *remote;
 	const char *url;
@@ -110,6 +116,8 @@ struct transport {
 	 * actually turns out to be smart.
 	 */
 	struct git_transport_options *smart_options;
+
+	enum transport_family family;
 };
 
 #define TRANSPORT_PUSH_ALL 1