From 0eccbd66c5ee0cffbbd4b37b8d0872b13a1ea563 Mon Sep 17 00:00:00 2001
From: cel <cel@f/6sQ6d2CMxRUhLpspgGIulDxDCwYD7DzFzPNr7u5AU=.ed25519>
Date: Thu, 4 Oct 2018 12:57:30 -1000
Subject: [PATCH] Add -4, -6 options (IPv4/IPv6)

---
 sbotc.1 | 11 +++++++++++
 sbotc.c | 27 ++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/sbotc.1 b/sbotc.1
index 57aed60..d91fb77 100644
--- a/sbotc.1
+++ b/sbotc.1
@@ -21,6 +21,11 @@
 .Oo
 .Op Fl s Ar host
 .Op Fl p Ar port
+.Oo
+.Fl 4
+|
+.Fl 6
+.Oc
 |
 .Op Fl u Ar socket_path
 .Oc
@@ -47,6 +52,10 @@ This option makes the
 and
 .Fl c
 options have no effect and output a warning if used.
+.It Fl 4
+Connect to server over IPv4 only.
+.It Fl 6
+Connect to server over IPv6 only.
 .It Fl c Ar cap
 Capability key for secret-handshake. Default is SSB's capability key,
 .Li 1KHLiKZvAvjbY1ziZEHMXawbCEIM6qwjCDm3VYRan/s= .
@@ -119,6 +128,8 @@ If none of the options
 .Fl k ,
 .Fl K ,
 .Fl c ,
+.Fl 4 ,
+.Fl 6 ,
 or
 .Fl T
 are specified,
diff --git a/sbotc.c b/sbotc.c
index 5a50754..250e55d 100644
--- a/sbotc.c
+++ b/sbotc.c
@@ -87,6 +87,12 @@ enum stream_state {
 	stream_state_ended_error,
 };
 
+enum ip_family {
+	ip_family_ipv4 = AF_INET,
+	ip_family_ipv6 = AF_INET6,
+	ip_family_any = AF_UNSPEC
+};
+
 static unsigned char zeros[24] = {0};
 
 static const unsigned char ssb_cap[] = {
@@ -99,12 +105,12 @@ static const unsigned char ssb_cap[] = {
 static void usage() {
 	fputs("usage: sbotc [-j] [-T]\n"
 	      "             [ -n | [-c <cap>] [-k <key>] [-K <keypair_seed>] ]\n"
-	      "             [ [-s <host>] [-p <port>] | [-u <socket_path>] ]\n"
+	      "             [ [-s <host>] [-p <port>] [ -4 | -6 ] | [-u <socket_path>] ]\n"
 	      "             [-t <type>] <method> [<argument>...]\n", stderr);
 	exit(EXIT_FAILURE);
 }
 
-static int tcp_connect(const char *host, const char *port) {
+static int tcp_connect(const char *host, const char *port, enum ip_family ip_family) {
 	struct addrinfo hints;
 	struct addrinfo *result, *rp;
 	int s;
@@ -112,7 +118,7 @@ static int tcp_connect(const char *host, const char *port) {
 	int err;
 
 	memset(&hints, 0, sizeof(hints));
-	hints.ai_family = AF_UNSPEC;
+	hints.ai_family = ip_family;
 	hints.ai_protocol = IPPROTO_TCP;
 
 	s = getaddrinfo(host, port, &hints, &result);
@@ -863,6 +869,9 @@ int main(int argc, char *argv[]) {
 	bool port_arg = false;
 	bool key_arg = false;
 	bool shs_cap_key_str_arg = false;
+	bool ipv4_arg = false;
+	bool ipv6_arg = false;
+	enum ip_family ip_family;
 
 	get_app_dir(app_dir, sizeof(app_dir));
 
@@ -893,11 +902,19 @@ int main(int argc, char *argv[]) {
 			case 'u': socket_path = argv[++i]; break;
 			case 't': typestr = argv[++i]; break;
 			case 'n': noauth = true; break;
+			case '4': ipv4_arg = true; break;
+			case '6': ipv6_arg = true; break;
 			default: usage();
 		}
 	}
 	if (i < argc) methodstr = argv[i++]; else if (!test) usage();
 
+	if (ipv4_arg && ipv6_arg) errx(1, "options -4 and -6 conflict");
+	ip_family =
+		ipv4_arg ? ip_family_ipv4 :
+		ipv6_arg ? ip_family_ipv6 :
+		ip_family_any;
+
 	if (shs_cap_key_str) {
 		rc = pubkey_decode(shs_cap_key_str, shs_cap_key);
 		if (rc < 0) err(1, "unable to decode cap key '%s'", shs_cap_key_str);
@@ -957,7 +974,7 @@ int main(int argc, char *argv[]) {
 		memcpy(remote_key, public_key, 32);
 	}
 
-	bool implied_tcp = host_arg || port_arg;
+	bool implied_tcp = host_arg || port_arg || ipv4_arg || ipv6_arg;
 	bool implied_auth = key_arg || keypair_seed_str || shs_cap_key_str_arg || test;
 
 	if (test) {
@@ -984,7 +1001,7 @@ int main(int argc, char *argv[]) {
 
 	} else {
 do_tcp_connect:
-		s = tcp_connect(host, port);
+		s = tcp_connect(host, port, ip_family);
 		if (s < 0) err(1, "tcp_connect");
 		infd = outfd = s;
 	}