The ngx_sock_ntop() function, when told to print both address and port,
prints IPv6 address in square brackets, followed by colon and port.
#if (NGX_HAVE_UNIX_DOMAIN)
#define NGX_SOCKADDR_STRLEN (sizeof("unix:") - 1 + NGX_UNIX_ADDRSTRLEN)
#else
-#define NGX_SOCKADDR_STRLEN (NGX_INET6_ADDRSTRLEN + sizeof(":65535") - 1)
+#define NGX_SOCKADDR_STRLEN (NGX_INET6_ADDRSTRLEN + sizeof("[]:65535") - 1)
#endif
#if (NGX_HAVE_UNIX_DOMAIN)