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