proto_ws: enclose IPv6 Host IPs with square brackets

Many thanks to @alekseiZh on GitHub for reporting it
Close #3198

(cherry picked from commit 3b4beb2)

modules/proto_ws/ws_handshake_common.h

@@ -103,7 +103,7 @@
 	"Sec-WebSocket-Protocol: " WS_PROTO_SIP HTTP_END
 #define HTTP_HANDSHAKE_END_LEN (sizeof(HTTP_HANDSHAKE_END) - 1)
 
-#define MAX_HOST_LEN IP_ADDR_MAX_STR_SIZE /*IP*/ + 1 /*':'*/ + 5 /*65535*/
+#define MAX_HOST_LEN IP_ADDR_MAX_STR_SIZE /*IP*/ + 2 /* '[' & ']' for ipv6 */ + 1 /*':'*/ + 5 /*65535*/
 
 #include "../../sha1.h"
 
@@ -1273,6 +1273,7 @@ static int ws_start_handshake(struct tcp_connection *c)
 	char *port;
 	int port_len;
 	static char host_orig_buf[MAX_HOST_LEN];
+	char *h;
 
 	str trace_str = { ws_trace_buf, 0 };
 
@@ -1303,14 +1304,21 @@ static int ws_start_handshake(struct tcp_connection *c)
 	ip = ip_addr2a(&c->rcv.src_ip);
 	port = int2str(c->rcv.src_port, &port_len);
 	n = strlen(ip);
-	memcpy(host_orig_buf, ip, n);
-	host_orig_buf[n] = ':';
-	memcpy(host_orig_buf + n + 1, port, port_len);
+	h = host_orig_buf;
+	if (c->rcv.src_ip.af == AF_INET6)
+		*h++ = '[';
+	memcpy(h, ip, n);
+	h += n;
+	if (c->rcv.src_ip.af == AF_INET6)
+		*h++ = ']';
+	*h++ = ':';
+	memcpy(h, port, port_len);
+	h += port_len;
 
 	iov[2].iov_base = _ws_common_resource.s;
 	iov[2].iov_len = _ws_common_resource.len;
 
-	iov[7].iov_len = n + port_len + 1;
+	iov[7].iov_len = h - host_orig_buf;
 	iov[10].iov_len = iov[7].iov_len;
 
 	iov[13].iov_base = WS_KEY(c).s;