chan_mgcp.c

Asterisk中信道部分的源码 。。。。

	p->capability = capability & peercapability;
	if (mgcpdebug) {
		ast_verbose("Capabilities: us - %d, them - %d, combined - %d\n",
			capability, peercapability, p->capability);
		ast_verbose("Non-codec capabilities: us - %d, them - %d, combined - %d\n",
			nonCodecCapability, peerNonCodecCapability, p->nonCodecCapability);
	}
	if (!p->capability) {
		ast_log(LOG_WARNING, "No compatible codecs!\n");
		return -1;
	}
	return 0;
}

static int add_header(struct mgcp_request *req, char *var, char *value)
{
	if (req->len >= sizeof(req->data) - 4) {
		ast_log(LOG_WARNING, "Out of space, can't add anymore\n");
		return -1;
	}
	if (req->lines) {
		ast_log(LOG_WARNING, "Can't add more headers when lines have been added\n");
		return -1;
	}
	req->header[req->headers] = req->data + req->len;
	snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s: %s\r\n", var, value);
	req->len += strlen(req->header[req->headers]);
	if (req->headers < MGCP_MAX_HEADERS)
		req->headers++;
	else {
		ast_log(LOG_WARNING, "Out of header space\n");
		return -1;
	}
	return 0;	
}

static int add_line(struct mgcp_request *req, char *line)
{
	if (req->len >= sizeof(req->data) - 4) {
		ast_log(LOG_WARNING, "Out of space, can't add anymore\n");
		return -1;
	}
	if (!req->lines) {
		/* Add extra empty return */
		snprintf(req->data + req->len, sizeof(req->data) - req->len, "\r\n");
		req->len += strlen(req->data + req->len);
	}
	req->line[req->lines] = req->data + req->len;
	snprintf(req->line[req->lines], sizeof(req->data) - req->len, "%s", line);
	req->len += strlen(req->line[req->lines]);
	if (req->lines < MGCP_MAX_LINES)
		req->lines++;
	else {
		ast_log(LOG_WARNING, "Out of line space\n");
		return -1;
	}
	return 0;	
}

static int init_resp(struct mgcp_request *req, char *resp, struct mgcp_request *orig, char *resprest)
{
	/* Initialize a response */
	if (req->headers || req->len) {
		ast_log(LOG_WARNING, "Request already initialized?!?\n");
		return -1;
	}
	req->header[req->headers] = req->data + req->len;
	snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s %s %s\r\n", resp, orig->identifier, resprest);
	req->len += strlen(req->header[req->headers]);
	if (req->headers < MGCP_MAX_HEADERS)
		req->headers++;
	else
		ast_log(LOG_WARNING, "Out of header space\n");
	return 0;
}

static int init_req(struct mgcp_endpoint *p, struct mgcp_request *req, char *verb)
{
	/* Initialize a response */
	if (req->headers || req->len) {
		ast_log(LOG_WARNING, "Request already initialized?!?\n");
		return -1;
	}
	req->header[req->headers] = req->data + req->len;
	/* check if we need brackets around the gw name */
	if (p->parent->isnamedottedip)
		snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s %d %s@[%s] MGCP 1.0\r\n", verb, oseq, p->name, p->parent->name);
	else
		snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s %d %s@%s MGCP 1.0\r\n", verb, oseq, p->name, p->parent->name);
	req->len += strlen(req->header[req->headers]);
	if (req->headers < MGCP_MAX_HEADERS)
		req->headers++;
	else
		ast_log(LOG_WARNING, "Out of header space\n");
	return 0;
}


static int respprep(struct mgcp_request *resp, struct mgcp_endpoint *p, char *msg, struct mgcp_request *req, char *msgrest)
{
	memset(resp, 0, sizeof(*resp));
	init_resp(resp, msg, req, msgrest);
	return 0;
}

static int reqprep(struct mgcp_request *req, struct mgcp_endpoint *p, char *verb)
{
	memset(req, 0, sizeof(struct mgcp_request));
	oseq++;
	if (oseq > 999999999)
		oseq = 1;
	init_req(p, req, verb);
	return 0;
}

static int transmit_response(struct mgcp_subchannel *sub, char *msg, struct mgcp_request *req, char *msgrest)
{
	struct mgcp_request resp;
	struct mgcp_endpoint *p = sub->parent;
	struct mgcp_response *mgr;

	respprep(&resp, p, msg, req, msgrest);
	mgr = malloc(sizeof(struct mgcp_response) + resp.len + 1);
	if (mgr) {
		/* Store MGCP response in case we have to retransmit */
		memset(mgr, 0, sizeof(struct mgcp_response));
		sscanf(req->identifier, "%d", &mgr->seqno);
		time(&mgr->whensent);
		mgr->len = resp.len;
		memcpy(mgr->buf, resp.data, resp.len);
		mgr->buf[resp.len] = '\0';
		mgr->next = p->parent->responses;
		p->parent->responses = mgr;
	}
	return send_response(sub, &resp);
}


static int add_sdp(struct mgcp_request *resp, struct mgcp_subchannel *sub, struct ast_rtp *rtp)
{
	int len;
	int codec;
	char costr[80];
	struct sockaddr_in sin;
	char v[256];
	char s[256];
	char o[256];
	char c[256];
	char t[256];
	char m[256] = "";
	char a[1024] = "";
	int x;
	struct sockaddr_in dest;
	struct mgcp_endpoint *p = sub->parent;
	/* XXX We break with the "recommendation" and send our IP, in order that our
	       peer doesn't have to ast_gethostbyname() us XXX */
	len = 0;
	if (!sub->rtp) {
		ast_log(LOG_WARNING, "No way to add SDP without an RTP structure\n");
		return -1;
	}
	ast_rtp_get_us(sub->rtp, &sin);
	if (rtp) {
		ast_rtp_get_peer(rtp, &dest);
	} else {
		if (sub->tmpdest.sin_addr.s_addr) {
			dest.sin_addr = sub->tmpdest.sin_addr;
			dest.sin_port = sub->tmpdest.sin_port;
			/* Reset temporary destination */
			memset(&sub->tmpdest, 0, sizeof(sub->tmpdest));
		} else {
			dest.sin_addr = p->parent->ourip;
			dest.sin_port = sin.sin_port;
		}
	}
	if (mgcpdebug) {
		ast_verbose("We're at %s port %d\n", ast_inet_ntoa(p->parent->ourip), ntohs(sin.sin_port));
	}
	snprintf(v, sizeof(v), "v=0\r\n");
	snprintf(o, sizeof(o), "o=root %d %d IN IP4 %s\r\n", (int)getpid(), (int)getpid(), ast_inet_ntoa(dest.sin_addr));
	snprintf(s, sizeof(s), "s=session\r\n");
	snprintf(c, sizeof(c), "c=IN IP4 %s\r\n", ast_inet_ntoa(dest.sin_addr));
	snprintf(t, sizeof(t), "t=0 0\r\n");
	snprintf(m, sizeof(m), "m=audio %d RTP/AVP", ntohs(dest.sin_port));
	for (x = 1; x <= AST_FORMAT_MAX_AUDIO; x <<= 1) {
		if (p->capability & x) {
			if (mgcpdebug) {
				ast_verbose("Answering with capability %d\n", x);
			}
			codec = ast_rtp_lookup_code(sub->rtp, 1, x);
			if (codec > -1) {
				snprintf(costr, sizeof(costr), " %d", codec);
				strncat(m, costr, sizeof(m) - strlen(m) - 1);
				snprintf(costr, sizeof(costr), "a=rtpmap:%d %s/8000\r\n", codec, ast_rtp_lookup_mime_subtype(1, x, 0));
				strncat(a, costr, sizeof(a) - strlen(a) - 1);
			}
		}
	}
	for (x = 1; x <= AST_RTP_MAX; x <<= 1) {
		if (p->nonCodecCapability & x) {
			if (mgcpdebug) {
				ast_verbose("Answering with non-codec capability %d\n", x);
			}
			codec = ast_rtp_lookup_code(sub->rtp, 0, x);
			if (codec > -1) {
				snprintf(costr, sizeof(costr), " %d", codec);
				strncat(m, costr, sizeof(m) - strlen(m) - 1);
				snprintf(costr, sizeof(costr), "a=rtpmap:%d %s/8000\r\n", codec, ast_rtp_lookup_mime_subtype(0, x, 0));
				strncat(a, costr, sizeof(a) - strlen(a) - 1);
				if (x == AST_RTP_DTMF) {
					/* Indicate we support DTMF...  Not sure about 16,
					   but MSN supports it so dang it, we will too... */
					snprintf(costr, sizeof costr, "a=fmtp:%d 0-16\r\n", codec);
					strncat(a, costr, sizeof(a) - strlen(a) - 1);
				}
			}
		}
	}
	strncat(m, "\r\n", sizeof(m) - strlen(m) - 1);
	len = strlen(v) + strlen(s) + strlen(o) + strlen(c) + strlen(t) + strlen(m) + strlen(a);
	snprintf(costr, sizeof(costr), "%d", len);
	add_line(resp, v);
	add_line(resp, o);
	add_line(resp, s);
	add_line(resp, c);
	add_line(resp, t);
	add_line(resp, m);
	add_line(resp, a);
	return 0;
}

static int transmit_modify_with_sdp(struct mgcp_subchannel *sub, struct ast_rtp *rtp, int codecs)
{
	struct mgcp_request resp;
	char local[256];
	char tmp[80];
	int x;
	int capability;
	struct mgcp_endpoint *p = sub->parent;

	capability = p->capability;
	if (codecs)
		capability = codecs;
	if (ast_strlen_zero(sub->cxident) && rtp) {
		/* We don't have a CXident yet, store the destination and
		   wait a bit */
		ast_rtp_get_peer(rtp, &sub->tmpdest);
		return 0;
	}
	snprintf(local, sizeof(local), "p:20");
	for (x=1;x<= AST_FORMAT_MAX_AUDIO; x <<= 1) {
		if (p->capability & x) {
			snprintf(tmp, sizeof(tmp), ", a:%s", ast_rtp_lookup_mime_subtype(1, x, 0));
			strncat(local, tmp, sizeof(local) - strlen(local) - 1);
		}
	}
	reqprep(&resp, p, "MDCX");
	add_header(&resp, "C", sub->callid);
	add_header(&resp, "L", local);
	add_header(&resp, "M", mgcp_cxmodes[sub->cxmode]);
	/* X header should not be sent. kept for compatibility */
	add_header(&resp, "X", sub->txident);
	add_header(&resp, "I", sub->cxident);
	/*add_header(&resp, "S", "");*/
	add_sdp(&resp, sub, rtp);
	/* fill in new fields */
	resp.cmd = MGCP_CMD_MDCX;
	resp.trid = oseq;
	return send_request(p, sub, &resp, oseq); /* SC */
}

static int transmit_connect_with_sdp(struct mgcp_subchannel *sub, struct ast_rtp *rtp)
{
	struct mgcp_request resp;
	char local[256];
	char tmp[80];
	int x;
	struct mgcp_endpoint *p = sub->parent;

	snprintf(local, sizeof(local), "p:20");
	for (x=1;x<= AST_FORMAT_MAX_AUDIO; x <<= 1) {
		if (p->capability & x) {
			snprintf(tmp, sizeof(tmp), ", a:%s", ast_rtp_lookup_mime_subtype(1, x, 0));
			strncat(local, tmp, sizeof(local) - strlen(local) - 1);
		}
	}
	if (mgcpdebug) {
		ast_verbose(VERBOSE_PREFIX_3 "Creating connection for %s@%s-%d in cxmode: %s callid: %s\n", 
			p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);
	}
	reqprep(&resp, p, "CRCX");
	add_header(&resp, "C", sub->callid);
	add_header(&resp, "L", local);
	add_header(&resp, "M", mgcp_cxmodes[sub->cxmode]);
	/* X header should not be sent. kept for compatibility */
	add_header(&resp, "X", sub->txident);
	/*add_header(&resp, "S", "");*/
	add_sdp(&resp, sub, rtp);
	/* fill in new fields */
	resp.cmd = MGCP_CMD_CRCX;
	resp.trid = oseq;
	return send_request(p, sub, &resp, oseq);  /* SC */
}

static int transmit_notify_request(struct mgcp_subchannel *sub, char *tone)
{
	struct mgcp_request resp;
	struct mgcp_endpoint *p = sub->parent;

	if (mgcpdebug) {
		ast_verbose(VERBOSE_PREFIX_3 "MGCP Asked to indicate tone: %s on  %s@%s-%d in cxmode: %s\n", 
			tone, p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode]);
	}
	ast_copy_string(p->curtone, tone, sizeof(p->curtone));
	reqprep(&resp, p, "RQNT");
	add_header(&resp, "X", p->rqnt_ident); /* SC */
	switch (p->hookstate) {
	case MGCP_ONHOOK:
		add_header(&resp, "R", "L/hd(N)");
		break;
	case MGCP_OFFHOOK:
		add_header_offhook(sub, &resp);
		break;
	}
	if (!ast_strlen_zero(tone)) {
		add_header(&resp, "S", tone);
	}
	/* fill in new fields */
	resp.cmd = MGCP_CMD_RQNT;
	resp.trid = oseq;
	return send_request(p, NULL, &resp, oseq); /* SC */
}

static int transmit_notify_request_with_callerid(struct mgcp_subchannel *sub, char *tone, char *callernum, char *callername)
{
	struct mgcp_request resp;
	char tone2[256];
	char *l, *n;
	time_t t;
	struct tm tm;
	struct mgcp_endpoint *p = sub->parent;
	
	time(&t);
	ast_localtime(&t, &tm, NULL);
	n = callername;
	l = callernum;
	if (!n)
		n = "";
	if (!l)
		l = "";

	/* Keep track of last callerid for blacklist and callreturn */
	ast_copy_string(p->lastcallerid, l, sizeof(p->lastcallerid));

	snprintf(tone2, sizeof(tone2), "%s,L/ci(%02d/%02d/%02d/%02d,%s,%s)", tone, 
		tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, l, n);
	ast_copy_string(p->curtone, tone, sizeof(p->curtone));
	reqprep(&resp, p, "RQNT");
	add_header(&resp, "X", p->rqnt_ident); /* SC */
	switch (p->hookstate) {
	case MGCP_ONHOOK:
		add_header(&resp, "R", "L/hd(N)");
		break;
	case MGCP_OFFHOOK:
		add_header_offhook(sub, &resp);
		break;
	}
	if (!ast_strlen_zero(tone2)) {
		add_header(&resp, "S", tone2);
	}
	if (mgcpdebug) {
		ast_verbose(VERBOSE_PREFIX_3 "MGCP Asked to indicate tone: %s on  %s@%s-%d in cxmode: %s\n", 
			tone2, p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode]);
	}
	/* fill in new fields */
	resp.cmd = MGCP_CMD_RQNT;
	resp.trid = oseq;
	return send_request(p, NULL, &resp, oseq);  /* SC */
}

static int transmit_modify_request(struct mgcp_subchannel *sub)
{
	struct mgcp_request resp;
	struct mgcp_endpoint *p = sub->parent;

	if (ast_strlen_zero(sub->cxident)) {
		/* We don't have a CXident yet, store the destination and
		   wait a bit */
		return 0;
	}
	if (mgcpdebug) {
		ast_verbose(VERBOSE_PREFIX_3 "Modified %s@%s-%d with new mode: %s on callid: %s\n", 
			p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);
	}
	reqprep(&resp, p, "MDCX");
	add_header(&resp, "C", sub->callid);
	add_header(&resp, "M", mgcp_cxmodes[sub->cxmode]);
	/* X header should not be sent. kept for compatibility */
	add_header(&resp, "X", sub->txident);
	add_header(&resp, "I", sub->cxident);
	switch (sub->parent->hookstate) {
	case MGCP_ONHOOK:
		add_header(&resp, "R", "L/hd(N)");
		break;
	case MGCP_OFFHOOK:
		add_header_offhook(sub, &resp);
		break;
	}
	/* fill in new fields */
	resp.cmd = MGCP_CMD_MDCX;
	resp.trid = oseq;
	return send_request(p, sub, &resp, oseq); /* SC */
}


static void add_header_offhook(struct mgcp_subchannel *sub, struct mgcp_request *resp)
{
	struct mgcp_endpoint *p = sub->parent;

	if (p && p->sub && p->sub->owner && p->sub->owner->_state >= AST_STATE_RINGING && (p->dtmfmode & (MGCP_DTMF_INBAND | MGCP_DTMF_HYBRID)))
		add_header(resp, "R", "L/hu(N),L/hf(N)");
	else
		add_header(resp, "R", "L/hu(N),L/hf(N),D/[0-9#*](N)");
}

static int transmit_audit_endpoint(struct mgcp_endpoint *p)
{
	struct mgcp_request resp;
	reqprep(&resp, p, "AUEP");
	/* removed unknown param VS */
	/*add_header(&resp, "F", "A,R,D,S,X,N,I,T,O,ES,E,MD,M");*/
	add_header(&resp, "F", "A");
	/* fill in new fields */
	resp.cmd = MGCP_CMD_AUEP;
	resp.trid = oseq;
	return send_request(p, NULL, &resp, oseq);  /* SC */
}

static int transmit_connection_del(struct mgcp_subchannel *sub)
{
	struct mgcp_endpoint *p = sub->parent;
	struct mgcp_request resp;

	if (mgcpdebug) {
		ast_verbose(VERBOSE_PREFIX_3 "Delete connection %s %s@%s-%d with new mode: %s on callid: %s\n", 
			sub->cxident, p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);
	}
	reqprep(&resp, p, "DLCX");
	/* check if call id is avail */
	if (sub->callid[0])
		add_header(&resp, "C", sub->callid);
	/* X header should not be sent. kept for compatibility */
	add_header(&resp, "X", sub->txident);
	/* check if cxident is avail */
	if (sub->cxident[0])
		add_header(&resp, "I", sub->cxident);
	/* fill in new fields */
	resp.cmd = MGCP_CMD_DLCX;
	resp.trid = oseq;
	return send_request(p, sub, &resp, oseq);  /* SC */
}

static int transmit_connection_del_w_params(struct mgcp_endpoint *p, char *callid, char *cxident)
{
	struct mgcp_request resp;

	if (mgcpdebug) {
		ast_verbose(VERBOSE_PREFIX_3 "Delete connection %s %s@%s on callid: %s\n", 
			cxident ? cxident : "", p->name, p->parent->name, callid ? callid : "");
	}
	reqprep(&resp, p, "DLCX");
	/* check if call id is avail */
	if (callid && *callid)
		add_heade