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/* MGCP message patching */
/*
* (C) 2011 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2011 by On-Waves
* All Rights Reserved
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <mgcp_patch.h>
#include <cellmgr_debug.h>
#include <ss7_application.h>
#include <string.h>
#include <osmocom/gsm/tlv.h>
struct msgb *mgcp_patch(struct ss7_application *app, struct msgb *msg)
{
char *token, *remaining;
struct msgb *out;
int len, out_len, state, i;
if (!app->mgcp_domain_name)
return msg;
if (msgb_tailroom(msg) <= strlen(app->mgcp_domain_name)) {
LOGP(DMGCP, LOGL_ERROR, "Not enough space to add a zero line.\n");
return msg;
}
msg->l2h[msgb_l2len(msg)] = '\0';
/**
* We now need to rewrite the message, but actually only the first
* line and the rest can be copied.
*/
out = msgb_alloc_headroom(4096, 128, "MGCP Patch Copy");
if (!out) {
LOGP(DMGCP, LOGL_ERROR, "Failed to create the MSGB copy.\n");
return NULL;
}
remaining = (char *) msg->l2h;
token = strsep(&remaining, "\n");
if (!token) {
LOGP(DMGCP, LOGL_ERROR, "Failed to split the MGCP.\n");
msgb_free(out);
return msg;
}
len = strlen(token);
out->l2h = msgb_put(out, 0);
/*
* State machine for copying and modifying the MGCP line, first find
* half of the endpoint, put ours, copy the rest of the line
*/
state = 0;
for (i = 0; i < len; ++i) {
switch (state) {
case 2:
if (token[i] == '@')
state += 1;
msgb_v_put(out, token[i]);
break;
case 3:
/* copy the new name */
out->l3h = msgb_put(out, strlen(app->mgcp_domain_name));
memcpy(out->l3h, app->mgcp_domain_name, msgb_l3len(out));
/* skip everything to the next whitespace */
for (; i < len; ++i) {
if (token[i] == ' ') {
break;
}
}
for (; i < len; ++i)
msgb_v_put(out, token[i]);
msgb_v_put(out, '\n');
break;
default:
if (token[i] == ' ')
state += 1;
msgb_v_put(out, token[i]);
break;
}
}
/* append the rest */
out_len = msgb_l2len(msg) - len - 1;
out->l3h = msgb_put(out, out_len);
memcpy(out->l3h, &msg->l2h[len + 1], out_len);
msgb_free(msg);
return out;
}
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