res/res_pjsip: Standardize/fix localnet checks across pjsip.

In 2dee95cc (ASTERISK-27024) and 776ffd77 (ASTERISK-26879) there was
confusion about whether the transport_state->localnet ACL has ALLOW or
DENY semantics.

For the record: the localnet has DENY semantics, meaning that "not in
the list" means ALLOW, and the local nets are in the list.

Therefore, checks like this look wrong, but are right:

    /* See if where we are sending this request is local or not, and if
       not that we can get a Contact URI to modify */
    if (ast_apply_ha(transport_state->localnet, &addr) != AST_SENSE_ALLOW) {
        ast_debug(5, "Request is being sent to local address, "
                     "skipping NAT manipulation\n");

(In the list == localnet == DENY == skip NAT manipulation.)

And conversely, other checks that looked right, were wrong.

This change adds two macro's to reduce the confusion and uses those
instead:

    ast_sip_transport_is_nonlocal(transport_state, addr)
    ast_sip_transport_is_local(transport_state, addr)

ASTERISK-27248 #close

Change-Id: Ie7767519eb5a822c4848e531a53c0fd054fae934

1 files changed, 10 insertions, 1 deletions

diff --git a/include/asterisk/res_pjsip.h b/include/asterisk/res_pjsip.h
index e2c487aa3..ad881382c 100644
--- a/include/asterisk/res_pjsip.h
+++ b/include/asterisk/res_pjsip.h
@@ -98,7 +98,10 @@ struct ast_sip_transport_state {
 	 */
 	pj_ssl_cipher ciphers[SIP_TLS_MAX_CIPHERS];
 	/*!
-	 * Optional local network information, used for NAT purposes
+	 * Optional local network information, used for NAT purposes.
+	 * "deny" (set) means that it's in the local network. Use the
+	 * ast_sip_transport_is_nonlocal and ast_sip_transport_is_local
+	 * macro's.
 	 * \since 13.8.0
 	 */
 	struct ast_ha *localnet;
@@ -124,6 +127,12 @@ struct ast_sip_transport_state {
 	struct ast_sockaddr external_media_address;
 };
 
+#define ast_sip_transport_is_nonlocal(transport_state, addr) \
+	(!transport_state->localnet || ast_apply_ha(transport_state->localnet, addr) == AST_SENSE_ALLOW)
+
+#define ast_sip_transport_is_local(transport_state, addr) \
+	(transport_state->localnet && ast_apply_ha(transport_state->localnet, addr) != AST_SENSE_ALLOW)
+
 /*
  * \brief Transport to bind to
  */