--- include/asterisk/iostream.h	(Asterisk 15.4)
+++ include/asterisk/iostream.h	(working copy)
@@ -26,19 +26,17 @@
  */
 
+#include "asterisk.h"           /* for size_t, ssize_t, HAVE_OPENSSL */
+
 #if defined(HAVE_OPENSSL)
 #define DO_SSL  /* comment in/out if you want to support ssl */
 #endif
 
-#ifdef DO_SSL
-#include <openssl/ssl.h>
-#include <openssl/err.h>
-#include <openssl/x509v3.h>
-#else
-/* declare dummy types so we can define a pointer to them */
-typedef struct {} SSL;
-typedef struct {} SSL_CTX;
-#endif /* DO_SSL */
+struct ssl_st;                  /* forward declaration */
+struct ssl_ctx_st;              /* forward declaration */
+struct timeval;                 /* forward declaration */
+typedef struct ssl_st SSL;
+typedef struct ssl_ctx_st SSL_CTX;
 
-struct ast_iostream;
+struct ast_iostream;            /* forward declaration */
 
 /*!
--- main/iostream.c	(Asterisk 15.4)
+++ main/iostream.c	(working copy)
@@ -19,10 +19,21 @@
 #include "asterisk.h"
 
-#include <fcntl.h>
-#include <stdarg.h>
+#include "asterisk/iostream.h"          /* for DO_SSL */
 
-#include "asterisk/utils.h"
-#include "asterisk/astobj2.h"
-#include "asterisk/iostream.h"
+#include <fcntl.h>                      /* for O_NONBLOCK */
+#ifdef DO_SSL
+#include <openssl/err.h>                /* for ERR_error_string */
+#include <openssl/opensslv.h>           /* for OPENSSL_VERSION_NUMBER */
+#include <openssl/ssl.h>                /* for SSL_get_error, SSL_free, SSL_... */
+#endif
+#include <sys/socket.h>                 /* for shutdown, SHUT_RDWR */
+#include <sys/time.h>                   /* for timeval */
+
+#include "asterisk/astobj2.h"           /* for ao2_alloc_options, ao2_alloc_... */
+#include "asterisk/logger.h"            /* for ast_debug, ast_log, LOG_ERROR */
+#include "asterisk/strings.h"           /* for asterisk/threadstorage.h */
+#include "asterisk/threadstorage.h"     /* for ast_threadstorage_get, AST_TH... */
+#include "asterisk/time.h"              /* for ast_remaining_ms, ast_tvnow */
+#include "asterisk/utils.h"             /* for ast_wait_for_input, ast_wait_... */
 
 struct ast_iostream {
--- main/tcptls.c	(Asterisk 15.4)
+++ main/tcptls.c	(working copy)
@@ -26,29 +26,46 @@
  */
 
-/*** MODULEINFO
-	<use type="external">openssl</use>
-	<support_level>core</support_level>
- ***/
-
 #include "asterisk.h"
 
-#ifdef HAVE_FCNTL_H
-#include <fcntl.h>
-#endif
-
-#include <signal.h>
-#include <sys/stat.h>
+#include "asterisk/tcptls.h"            /* for ast_tls_config, ast_tcptls_se... */
+#include "asterisk/iostream.h"          /* for DO_SSL, ast_iostream_close, a... */
 
-#include "asterisk/compat.h"
-#include "asterisk/tcptls.h"
-#include "asterisk/io.h"
-#include "asterisk/http.h"
-#include "asterisk/utils.h"
-#include "asterisk/strings.h"
-#include "asterisk/options.h"
-#include "asterisk/manager.h"
-#include "asterisk/astobj2.h"
-#include "asterisk/pbx.h"
-#include "asterisk/app.h"
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>                      /* for O_NONBLOCK */
+#endif /* HAVE_FCNTL_H */
+#include <netinet/in.h>                 /* for IPPROTO_TCP */
+#ifdef DO_SSL
+#include <openssl/asn1.h>               /* for ASN1_STRING_to_UTF8 */
+#include <openssl/crypto.h>             /* for OPENSSL_free */
+#include <openssl/opensslconf.h>        /* for OPENSSL_NO_SSL3_METHOD, OPENS... */
+#include <openssl/opensslv.h>           /* for OPENSSL_VERSION_NUMBER */
+#include <openssl/safestack.h>          /* for STACK_OF */
+#include <openssl/ssl.h>                /* for SSL_CTX_free, SSL_get_error, ... */
+#include <openssl/x509.h>               /* for X509_free, X509_NAME_ENTRY_ge... */
+#include <openssl/x509v3.h>             /* for GENERAL_NAME, sk_GENERAL_NAME... */
+#ifndef OPENSSL_NO_DH
+#include <openssl/bio.h>                /* for BIO_free, BIO_new_file */
+#include <openssl/dh.h>                 /* for DH_free */
+#include <openssl/pem.h>                /* for PEM_read_bio_DHparams */
+#endif /* OPENSSL_NO_DH */
+#ifndef OPENSSL_NO_EC
+#include <openssl/ec.h>                 /* for EC_KEY_free, EC_KEY_new_by_cu... */
+#endif /* OPENSSL_NO_EC */
+#endif /* DO_SSL */
+#include <pthread.h>                    /* for pthread_cancel, pthread_join */
+#include <signal.h>                     /* for pthread_kill, SIGURG */
+#include <sys/socket.h>                 /* for setsockopt, shutdown, socket */
+#include <sys/stat.h>                   /* for stat */
+
+#include "asterisk/app.h"               /* for ast_read_textfile */
+#include "asterisk/astobj2.h"           /* for ao2_ref, ao2_t_ref, ao2_alloc */
+#include "asterisk/compat.h"            /* for strcasecmp */
+#include "asterisk/config.h"            /* for ast_parse_arg, ast_parse_flag... */
+#include "asterisk/io.h"                /* for ast_sd_get_fd */
+#include "asterisk/lock.h"              /* for AST_PTHREADT_NULL */
+#include "asterisk/logger.h"            /* for ast_log, LOG_ERROR, ast_debug */
+#include "asterisk/netsock2.h"          /* for ast_sockaddr_copy, ast_sockad... */
+#include "asterisk/pbx.h"               /* for ast_thread_inhibit_escalations */
+#include "asterisk/utils.h"             /* for ast_true, ast_free, ast_wait_... */
 
 static void session_instance_destructor(void *obj)
--- main/Makefile	(Asterisk 15.4)
+++ main/Makefile	(working copy)
@@ -311,2 +311,3 @@
 
+iostream.o: _ASTCFLAGS+=$(OPENSSL_INCLUDE)
 tcptls.o: _ASTCFLAGS+=$(OPENSSL_INCLUDE) -Wno-deprecated-declarations
--- include/asterisk/tcptls.h	(Asterisk 15.4)
+++ include/asterisk/tcptls.h	(working copy)
@@ -47,8 +47,4 @@
  *
  * \ref AstTlsOverview
- *
- * \todo For SIP, the SubjectAltNames should be checked on verification
- *       of the certificate. (Check RFC 5922)
- *
  */
 
@@ -56,7 +52,13 @@
 #define _ASTERISK_TCPTLS_H
 
-#include "asterisk/netsock2.h"
-#include "asterisk/utils.h"
+#include <pthread.h>            /* for pthread_t */
+#include <sys/param.h>          /* for MAXHOSTNAMELEN */
+
 #include "asterisk/iostream.h"
+#include "asterisk/netsock2.h"  /* for ast_sockaddr */
+#include "asterisk/utils.h"     /* for ast_flags */
+
+struct ssl_ctx_st;              /* forward declaration */
+typedef struct ssl_ctx_st SSL_CTX;
 
 /*! SSL support */