266 lines
6.6 KiB
C
266 lines
6.6 KiB
C
/*
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This file is part of libcapwap.
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libcapwap is free software: you can redistribute it and/or modify
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it under the terms of the GNU 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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libcapwap 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 General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Foobar. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file
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* @brief Processing of incomming messaages.
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*/
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#include <stdint.h>
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#include <stdio.h>
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#include "conn.h"
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#include "capwap.h"
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#include "capwap_items.h"
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#include "sock.h"
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#include "action.h"
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#include "cw_log.h"
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#include "dbg.h"
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int conn_send_msg(struct conn *conn, uint8_t * rawmsg);
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/**
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* Init response message header
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*/
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void cw_init_response(struct conn *conn, uint8_t * req)
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{
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uint8_t *buffer = conn->resp_buffer;
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int shbytes = cw_get_hdr_msg_offset(req);
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int dhbytes;
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memcpy(buffer, req, shbytes);
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cw_set_hdr_hlen(buffer, 2);
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cw_set_hdr_flags(buffer, CW_FLAG_HDR_M, 1);
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dhbytes = cw_get_hdr_msg_offset(buffer);
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uint8_t *msgptr = req + shbytes;
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uint8_t *dmsgptr = buffer + dhbytes;
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cw_set_msg_type(dmsgptr, cw_get_msg_type(msgptr) + 1);
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cw_set_msg_seqnum(dmsgptr, cw_get_msg_seqnum(msgptr));
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cw_set_msg_flags(dmsgptr, 0);
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}
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void cw_init_request(struct conn *conn, int msg_id)
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{
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uint8_t *buffer = conn->req_buffer;
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cw_put_dword(buffer + 0, 0);
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/* unencrypted */
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cw_put_hdr_preamble(CAPWAP_VERSION<<8 | 0);
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cw_put_dword(buffer + 4, 0);
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cw_set_hdr_preamble(buffer, 0);
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cw_set_hdr_hlen(buffer, 2);
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cw_set_hdr_wbid(buffer, 1);
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cw_set_hdr_rid(buffer, 0);
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uint8_t *msgptr = cw_get_hdr_msg_offset(buffer) + buffer;
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cw_set_msg_type(msgptr, msg_id);
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cw_set_msg_flags(msgptr, 0);
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cw_set_msg_elems_len(msgptr, 0);
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}
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/**
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* send a response
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*/
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int cw_send_response(struct conn *conn, uint8_t * rawmsg, int len)
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{
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cw_init_response(conn, rawmsg);
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if (cw_put_msg(conn, conn->resp_buffer) == -1)
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return 0;
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conn_send_msg(conn, conn->resp_buffer);
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return 1;
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}
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/**
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* Special case error message, which is sent when an unexpected messages
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* was received or somethin else happened.
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* @param conn conection
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* @param rawmsg the received request message, which the response belongs to
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* @pqram result_code result code to send
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* @return 1
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*/
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int cw_send_error_response(struct conn *conn, uint8_t * rawmsg, uint32_t result_code)
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{
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cw_init_response(conn, rawmsg);
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uint8_t *out = conn->resp_buffer;
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uint8_t *dst = cw_get_hdr_msg_elems_ptr(out);
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int l = cw_put_elem_result_code(dst, result_code);
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cw_set_msg_elems_len(out + cw_get_hdr_msg_offset(out), l);
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conn_send_msg(conn, conn->resp_buffer);
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return 1;
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}
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int cw_process_msg(struct conn *conn, uint8_t * rawmsg, int len)
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{
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struct cw_action_in as, *af, *afm;
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uint8_t *msg_ptr = rawmsg + cw_get_hdr_msg_offset(rawmsg);
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int elems_len = cw_get_msg_elems_len(msg_ptr);
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/*
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if (8+elems_len != len){
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cw_dbg(DBG_MSG_ERR,"Discarding message from %s, msgelems len=%d, data len=%d, (strict capwap) ",
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sock_addr2str(&conn->addr),elems_len,len-8);
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if (conn_is_strict_capwap(conn)){
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cw_dbg(DBG_MSG_ERR,"Discarding message from %s, msgelems len=%d, data len=%d, (strict capwap) ",
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sock_addr2str(&conn->addr),elems_len,len-8);
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return 0;
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}
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if (8+elems_len < len){
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cw_dbg(DBG_CW_RFC,"Packet from from %s has %d bytes extra data.",
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sock_addr2str(&conn->addr),len-8-elems_len);
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elems_len=len-8;
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}
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if (8+elems_len > len){
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cw_dbg(DBG_CW_RFC,"Packet from from %s hass msgelems len of %d bytes but has only %d bytes of data, truncating.",
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sock_addr2str(&conn->addr),elems_len,len-8);
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}
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return 1;
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}
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*/
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/* prepare struct for search operation */
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as.capwap_state = conn->capwap_state;
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as.msg_id = cw_get_msg_id(msg_ptr);
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as.vendor_id = 0;
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as.elem_id = 0;
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as.proto = 0;
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/* Search for state/message combination */
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afm = cw_actionlist_in_get(conn->actions->in, &as);
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if (!afm) {
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/* Throw away unexpected response messages */
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if (!(as.msg_id & 1)) {
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cw_dbg(DBG_MSG_ERR,
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"Message type %d (%s) unexpected/illigal in %s State, discarding.",
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as.msg_id, cw_strmsg(as.msg_id),
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cw_strstate(conn->capwap_state));
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return 0;
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}
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/* Request message not found in current state, check if we know
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anything else about this message type */
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const char *str = cw_strheap_get(conn->actions->strmsg, as.msg_id);
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int result_code = 0;
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if (str) {
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/* Message found, but it was in wrong state */
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cw_dbg(DBG_MSG_ERR,
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"Message type %d (%s) not allowed in %s State.", as.msg_id,
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cw_strmsg(as.msg_id), cw_strstate(as.capwap_state));
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result_code = CW_RESULT_MSG_INVALID_IN_CURRENT_STATE;
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} else {
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/* Message is unknown */
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cw_dbg(DBG_MSG_ERR, "Message type %d (%s) unknown.",
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as.msg_id, cw_strmsg(as.msg_id),
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cw_strstate(as.capwap_state));
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result_code = CW_RESULT_MSG_UNRECOGNIZED;
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}
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cw_send_error_response(conn, rawmsg, result_code);
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return 0;
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}
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/* Execute start processor for message */
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if (afm->start) {
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afm->start(conn, afm, rawmsg, len);
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}
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uint8_t *elems_ptr = cw_get_msg_elems_ptr(msg_ptr);
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uint8_t *elem;
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/* avltree to bag the found mandatory elements */
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conn->mand = intavltree_create();
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/* iterate through message elements */
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cw_foreach_elem(elem, elems_ptr, elems_len) {
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as.elem_id = cw_get_elem_id(elem);
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int elem_len = cw_get_elem_len(elem);
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cw_dbg_elem(conn, as.msg_id, as.elem_id, cw_get_elem_data(elem),
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elem_len);
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af = cw_actionlist_in_get(conn->actions->in, &as);
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if (!af) {
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cw_dbg(DBG_ELEM_ERR, "Element %d not allowed in msg %d (%s)",
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as.elem_id, as.msg_id, cw_strmsg(as.msg_id));
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continue;
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}
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if (af->mand) {
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/* add found mandatory message element
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to mand list */
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intavltree_add(conn->mand, af->item_id);
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}
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if (af->start) {
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af->start(conn, af, cw_get_elem_data(elem), elem_len);
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}
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}
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int result_code = 0;
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if (afm->end) {
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result_code = afm->end(conn, afm, rawmsg, len);
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}
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/* if we've got a request message, we always have to send a response message */
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if (as.msg_id & 1) {
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if (result_code > 0) {
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/* the end method gave us an result code, so
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send an error message */
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cw_send_error_response(conn, rawmsg, result_code);
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} else {
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/* regular response message */
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cw_send_response(conn, rawmsg, len);
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}
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}
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intavltree_destroy(conn->mand);
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return 0;
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}
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