* int ast_bridge_call(struct ast_channel *chan, struct ast_channel *peer, int allowredirect, int allowdisconnect)

• if (chan->_state != AST_STATE_UP) {
  • if (ast_answer(chan)) return -1;
• }
• for (;;) {
  • res = ast_channel_bridge(chan, peer, (allowdisconnect ? AST_BRIDGE_DTMF_CHANNEL_0 : 0) + (allowredirect ? AST_BRIDGE_DTMF_CHANNEL_1 : 0), &f, &who);
  • if (res < 0) return -1;
  • if (!f || ((f->frametype == AST_FRAME_CONTROL) && ((f->subclass == AST_CONTROL_HANGUP) || (f->subclass == AST_CONTROL_BUSY) || (f->subclass == AST_CONTROL_CONGESTION)))) {
    • res = -1;
    • break;
  • }
  • if ((f->frametype == AST_FRAME_CONTROL) && (f->subclass == AST_CONTROL_RINGING)) {
  • }
  • if ((f->frametype == AST_FRAME_CONTROL) && (f->subclass == AST_CONTROL_OPTION)) {
  • }
  • if (f && (f->frametype == AST_FRAME_DTMF) && (who == chan) && allowdisconnect && (f->subclass == '*')) {
    • res = -1;
    • break;
  • }
  • if ((f->frametype == AST_FRAME_DTMF) && (who == peer) && allowredirect && (f->subclass == '#')) {
  • } else {
  • }
• }
• return res;
  
  

* channel.c

• ast_channel_bridge
  • 입력된 내용이 AST_FRAME_CONTROL 이면, return 0
  • 입력된 내용은 fo 에, 누가에게서 입력된 것인가는 rc 에 assign

if ((f->frametype == AST_FRAME_CONTROL) && !(flags & AST_BRIDGE_IGNORE_SIGS)) {
                        *fo = f;
                        *rc = who;
                        res =  0;
                        break;
                }