Used to implement the new capwap mods
Will later replace conn_process_packet.c FossilOrigin-Name: 18235a3f2738496e8c58cf67e9925aeb273beb8808b1907b692f5c8ba252c6e6
This commit is contained in:
7u83@mail.ru
parent
f0bb6f8ca4
commit
55a18b64cf
529
src/capwap/conn_process_packet2.c
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529
src/capwap/conn_process_packet2.c
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@ -0,0 +1,529 @@
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/*
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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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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "capwap.h"
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#include "dbg.h"
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#include "log.h"
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#include "cw_util.h"
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#include "conn.h"
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#include "sock.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_rmac(buffer, conn->base_rmac);
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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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/* zero the first 8 bytes */
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cw_put_dword(buffer + 0, 0);
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cw_put_dword(buffer + 4, 0);
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/* unencrypted */
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cw_set_hdr_preamble(buffer, CAPWAP_VERSION << 4 | 0);
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cw_set_hdr_rmac(buffer, conn->base_rmac);
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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 something 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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static int process_elements(struct conn *conn, uint8_t * rawmsg, int len,
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struct sockaddr *from)
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{
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struct cw_action_in as, *af, *afm;
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int offset = cw_get_hdr_msg_offset(rawmsg);
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uint8_t *msg_ptr = rawmsg + offset;
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int elems_len = cw_get_msg_elems_len(msg_ptr);
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int payloadlen = len - offset;
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/* pre-check message */
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if (payloadlen - 8 != elems_len) {
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if (conn->strict_hdr) {
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cw_dbg(DBG_MSG_ERR,
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"Discarding message from %s, msgelems len=%d, payload len=%d, (Strict CAPWAP) ",
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sock_addr2str(&conn->addr), elems_len, payloadlen - 8);
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errno = EAGAIN;
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return -1;
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}
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if (elems_len < payloadlen - 8) {
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cw_dbg(DBG_RFC,
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"Packet from from %s has %d bytes of extra data, ignoring.",
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sock_addr2str(&conn->addr), payloadlen - 8 - elems_len);
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elems_len = len - 8;
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}
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if (elems_len > payloadlen - 8) {
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cw_dbg(DBG_RFC,
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"Packet from from %s has msgelems len of %d bytes, but has only %d bytes of data, truncating.",
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sock_addr2str(&conn->addr), elems_len, payloadlen - 8);
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elems_len = payloadlen - 8;
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}
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}
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if (!conn->detected) {
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if (conn->mods){
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struct mod_ac ** mods = (struct mod_ac **)conn->mods;
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int i;
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for (i=0; mods[i]; i++){
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if (mods[i]->detect){
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if (mods[i]->detect(conn,rawmsg,len,from)){
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cw_dbg(DBG_INFO,"Using mod '%s' to handle connection from %s",mods[i]->name,sock_addr2str(from));
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break;
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}
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}
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}
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}
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}
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if (!conn->detected){
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cw_dbg(DBG_INFO,"Cant't detect capwap, discarding message from %s",sock_addr2str(from));
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errno=EAGAIN;
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return -1;
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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/illegal 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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errno = EAGAIN;
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return -1;
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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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errno = EAGAIN;
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return -1;
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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, from);
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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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/* Create an avltree to catch 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(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,
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"Element %d (%s) not allowed in msg of type %d (%s), ignoring.",
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as.elem_id, cw_strelemp(conn->actions, as.elem_id),
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as.msg_id, cw_strmsg(as.msg_id));
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continue;
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}
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int afrc = 1;
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if (af->start) {
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afrc =
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af->start(conn, af, cw_get_elem_data(elem), elem_len, from);
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}
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if (af->mand && afrc) {
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/* add found mandatory message element
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to mand list */
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intavltree_add(conn->mand, (int) af->item_id);
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}
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}
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/* all message elements are processed, do now after processing
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by calling the "end" function for the message */
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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, from);
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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>0, 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 if (result_code == 0) {
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/* All ok, send regular response message */
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cw_send_response(conn, rawmsg, len);
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} else {
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/* the request message is ignored, no response
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will be sent */
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errno = EAGAIN;
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}
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} else {
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/*
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* Whe have got a response message.
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* Put further actions here, if needed.
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*/
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}
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intavltree_destroy(conn->mand);
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return result_code;
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}
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int process_message(struct conn *conn, uint8_t * rawmsg, int rawlen,
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struct sockaddr *from)
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{
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uint8_t *msgptr = rawmsg + cw_get_hdr_msg_offset(rawmsg);
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uint32_t type = cw_get_msg_type(msgptr);
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if (!(type & 0x1)) {
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/* It's a response message, no further examination required. */
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return process_elements(conn, rawmsg, rawlen, from);
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}
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/* It's a request message, check if seqnum is right and if
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* we have already sent a response message*/
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uint8_t seqnum = cw_get_msg_seqnum(msgptr);
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int s1 = conn->last_seqnum_received;
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int s2 = seqnum;
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int sd = s2 - s1;
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if ((sd > 0 && sd < 128) || (sd < 0 && sd < -128) || s1 < 0) {
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/* seqnum is ok, normal message processing */
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conn->last_seqnum_received = seqnum;
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return process_elements(conn, rawmsg, rawlen, from);
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}
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if (sd != 0) {
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cw_dbg(DBG_MSG_ERR,
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"Discarding message from %s, old seqnum, seqnum = %d, last seqnum=%d",
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sock_addr2str(&conn->addr), s2, s1);
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errno = EAGAIN;
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return -1;
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}
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/* the received request message was retransmittet by our peer,
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* let's retransmit our response message if we have one*/
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cw_dbg(DBG_MSG_ERR,
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"Retransmitted request message from %s detected, seqnum=%d, type=%d",
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sock_addr2str(&conn->addr), s2, type);
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if (cw_get_hdr_msg_type(conn->resp_buffer) - 1 != type) {
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cw_dbg(DBG_MSG_ERR,
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"No cached response for retransmission, request seqnum=%d,in cache=%d",
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s2, conn->resp_msg.type);
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errno = EAGAIN;
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return -1;
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}
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cw_dbg(DBG_MSG_ERR, "Retransmitting response message to %s, seqnum=%d",
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sock_addr2str(&conn->addr), s2);
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// XXX untested
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conn_send_msg(conn, conn->resp_buffer);
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errno = EAGAIN;
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return -1;
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}
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/*
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* Process an incomming CAPWAP packet, assuming the packet is already decrypted
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* @param conn conection object
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* @param packet pointer to packet data
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* @param len lenght of packet data
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*/
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int conn_process_packet(struct conn *conn, uint8_t * packet, int len,
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struct sockaddr *from)
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{
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/* show this packet in debug output */
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cw_dbg_pkt(DBG_PKT_IN, conn, packet, len, from);
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if (len < 8) {
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/* packet too short */
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cw_dbg(DBG_PKT_ERR,
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"Discarding packet from %s, packet too short, len=%d, at least 8 expected.",
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sock_addr2str(&conn->addr), len);
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errno = EAGAIN;
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return -1;
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}
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int preamble = cw_get_hdr_preamble(packet);
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if ((preamble & 0xf0) != (CAPWAP_VERSION << 4)) {
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/* wrong version */
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cw_dbg(DBG_PKT_ERR,
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"Discarding packet from %s, wrong version, version=%d, version %d expected.",
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sock_addr2str(&conn->addr), (preamble & 0xf0) >> 4,
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CAPWAP_VERSION);
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errno = EAGAIN;
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return -1;
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}
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if (preamble & 0xf) {
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/* Encrypted data, this shuold never happen here */
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cw_dbg(DBG_PKT_ERR,
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"Discarding packet from %s, encrypted data after decryption ...",
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sock_addr2str(&conn->addr));
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errno = EAGAIN;
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return -1;
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}
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int offs = cw_get_hdr_msg_offset(packet);
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int payloadlen = len - offs;
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if (payloadlen < 0) {
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/* Eleminate messages with wrong header size */
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cw_dbg(DBG_PKT_ERR,
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"Discarding packet from %s, header length (%d) greater than packet len (%d).",
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sock_addr2str(&conn->addr), offs, len);
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errno = EAGAIN;
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return -1;
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}
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/* Check if Radio MAC is present */
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if (cw_get_hdr_flag_m(packet)) {
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if (cw_get_hdr_rmac_len(packet) + 8 > offs) {
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/* wrong rmac size */
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cw_dbg(DBG_PKT_ERR,
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"Discarding packet from %s, wrong R-MAC size, size=%d",
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sock_addr2str(&conn->addr), *(packet + 8));
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errno = EAGAIN;
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return -1;
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}
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}
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if (cw_get_hdr_flag_f(packet)) {
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/* fragmented, add the packet to fragman */
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uint8_t *f;
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f = fragman_add(conn->fragman, packet, offs, payloadlen);
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if (f == NULL) {
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errno = EAGAIN;
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return -1;
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}
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cw_dbg_pkt(DBG_PKT_IN, conn, f + 4, *(uint32_t *) f, from);
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cw_dbg_msg(DBG_MSG_IN, conn, f + 4, *(uint32_t *) f, from);
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// XXX: Modify fragman to not throw away CAPWAP headers
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int rc = conn->process_message(conn, f + 4, *(uint32_t *) f, from);
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free(f);
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return rc;
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}
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/* not fragmented, we have a complete message */
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cw_dbg_msg(DBG_MSG_IN, conn, packet, len, from);
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||||
return conn->process_message(conn, packet, len, from);
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* Used as main message loop
|
||||
*/
|
||||
int cw_read_messages(struct conn *conn)
|
||||
{
|
||||
uint8_t buf[2024];
|
||||
int len = 2024;
|
||||
|
||||
int n = conn->read(conn, buf, len);
|
||||
if (n < 0)
|
||||
return n;
|
||||
|
||||
if (n > 0) {
|
||||
return conn->process_packet(conn, buf, n,
|
||||
(struct sockaddr *) &conn->addr);
|
||||
}
|
||||
errno = EAGAIN;
|
||||
return -1;
|
||||
}
|
||||
|
||||
int cw_read_from(struct conn *conn)
|
||||
{
|
||||
if (!conn->readfrom) {
|
||||
cw_log(LOG_ERR, "Fatal error, no readfrom method available.");
|
||||
errno = EPROTO;
|
||||
return -1;
|
||||
}
|
||||
uint8_t buf[2024];
|
||||
int len = 2024;
|
||||
|
||||
struct sockaddr_storage from;
|
||||
int n = conn->readfrom(conn, buf, len, &from);
|
||||
if (n < 0)
|
||||
return n;
|
||||
|
||||
if (n > 0) {
|
||||
return conn->process_packet(conn, buf, n, (struct sockaddr *) &from);
|
||||
}
|
||||
errno = EAGAIN;
|
||||
return -1;
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user