chan_dahdi: Fix Caller ID presentation for FXO ports.

Currently, the presentation for incoming channels is
always available, because it is never actually set,
meaning the channel presentation can be nonsensical.
If the presentation from the incoming Caller ID spill
is private or unavailable, we now update the channel
presentation to reflect this.

Resolves: #120
ASTERISK-30333
ASTERISK-21741

channels/chan_dahdi.c

@@ -1459,6 +1459,18 @@ static int my_get_callerid(void *pvt, char *namebuf, char *numbuf, enum analog_e
 			if (num)
 				ast_copy_string(numbuf, num, ANALOG_MAX_CID);
 
+			if (flags & (CID_PRIVATE_NUMBER | CID_UNKNOWN_NUMBER)) {
+				/* If we got a presentation, we must set it on the channel */
+				struct ast_channel *chan = analog_p->ss_astchan;
+				struct ast_party_caller caller;
+
+				ast_party_caller_set_init(&caller, ast_channel_caller(chan));
+				caller.id.name.presentation = caller.id.number.presentation = (flags & CID_PRIVATE_NUMBER) ?
+					AST_PRES_RESTRICTED | AST_PRES_USER_NUMBER_UNSCREENED : AST_PRES_UNAVAILABLE | AST_PRES_USER_NUMBER_UNSCREENED;
+				ast_party_caller_set(ast_channel_caller(chan), &caller, NULL);
+				ast_party_caller_free(&caller);
+			}
+
 			ast_debug(1, "CallerID number: %s, name: %s, flags=%d\n", num, name, flags);
 			return 0;
 		}