/*
This file is part of libcapwap.
libcapwap is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
libcapwap 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with Foobar. If not, see .
*/
#include
#include
#include
#include "cw.h"
#include "dbg.h"
#include "log.h"
#include "cw_util.h"
#include "conn.h"
#include "sock.h"
#include "stravltree.h"
#include "mod.h"
int conn_send_msg(struct conn *conn, uint8_t * rawmsg);
/**
* Init response message header
*/
void cw_init_response(struct conn *conn, uint8_t * req)
{
uint8_t *buffer = conn->resp_buffer;
int shbytes = cw_get_hdr_msg_offset(req);
int dhbytes;
memcpy(buffer, req, shbytes);
cw_set_hdr_rmac(buffer, conn->base_rmac);
// cw_set_hdr_hlen(buffer, 2);
// cw_set_hdr_flags(buffer, CW_FLAG_HDR_M, 1);
dhbytes = cw_get_hdr_msg_offset(buffer);
uint8_t *msgptr = req + shbytes;
uint8_t *dmsgptr = buffer + dhbytes;
cw_set_msg_type(dmsgptr, cw_get_msg_type(msgptr) + 1);
cw_set_msg_seqnum(dmsgptr, cw_get_msg_seqnum(msgptr));
cw_set_msg_flags(dmsgptr, 0);
}
void cw_init_request(struct conn *conn, int msg_id)
{
uint8_t *buffer = conn->req_buffer;
/* zero the first 8 bytes */
cw_put_dword(buffer + 0, 0);
cw_put_dword(buffer + 4, 0);
/* unencrypted */
cw_set_hdr_preamble(buffer, CAPWAP_VERSION << 4 | 0);
cw_set_hdr_rmac(buffer, conn->base_rmac);
//cw_set_hdr_hlen(buffer, 2);
cw_set_hdr_wbid(buffer, conn->wbid);
cw_set_hdr_rid(buffer, 0);
uint8_t *msgptr = cw_get_hdr_msg_offset(buffer) + buffer;
cw_set_msg_type(msgptr, msg_id);
cw_set_msg_flags(msgptr, 0);
cw_set_msg_elems_len(msgptr, 0);
}
void cw_init_data_msg(struct conn *conn)
{
uint8_t *buffer = conn->req_buffer;
cw_put_dword(buffer + 0, 0);
cw_put_dword(buffer + 4, 0);
/* unencrypted */
cw_set_hdr_preamble(buffer, CAPWAP_VERSION << 4 | 0);
}
/**
* send a response
*/
int cw_send_response(struct conn *conn, uint8_t * rawmsg, int len)
{
cw_init_response(conn, rawmsg);
if (cw_put_msg(conn, conn->resp_buffer) == -1)
return 0;
conn_send_msg(conn, conn->resp_buffer);
return 1;
}
/**
* Special case error message, which is sent when an unexpected messages
* was received or something else happened.
* @param conn conection
* @param rawmsg the received request message, which the response belongs to
* @param result_code result code to send
* @return 1
*/
int cw_send_error_response(struct conn *conn, uint8_t * rawmsg, uint32_t result_code)
{
cw_init_response(conn, rawmsg);
uint8_t *out = conn->resp_buffer;
uint8_t *dst = cw_get_hdr_msg_elems_ptr(out);
int l = cw_put_elem_result_code(dst, result_code);
cw_set_msg_elems_len(out + cw_get_hdr_msg_offset(out), l);
conn_send_msg(conn, conn->resp_buffer);
return 1;
}
static int check_len(struct conn *conn, struct cw_action_in *a, uint8_t * data, int len,
struct sockaddr *from)
{
if (!a->max_len)
return 1;
if (len < a->min_len) {
cw_dbg(DBG_ELEM_ERR,
"%d (%s) message element too short, len=%d, min len=%d",
a->elem_id, cw_strelemp(conn->actions, a->elem_id), len,
a->min_len);
return 0;
}
if (len > a->max_len) {
cw_dbg(DBG_ELEM_ERR,
"%d (%s) message element too big, len=%d, max len=%d", a->elem_id,
cw_strelemp(conn->actions, a->elem_id), len, a->max_len);
return 0;
}
return 1;
}
static struct mod_ac *detect_mod(struct conn *conn, uint8_t * rawmsg, int len,
int elems_len, struct sockaddr *from, int mode)
{
if (conn->mods) {
struct mod_ac **mods = (struct mod_ac **) conn->mods;
int i;
for (i = 0; mods[i]; i++) {
if (mods[i]->detect) {
if (mods[i]->detect
(conn, rawmsg, len, elems_len, from, mode)) {
return mods[i];
}
}
}
}
return MOD_NULL;
}
static struct cw_actiondef *load_mods(struct conn *conn, uint8_t * rawmsg, int len,
int elems_len, struct sockaddr *from)
{
struct mod_ac *cmod =
detect_mod(conn, rawmsg, len, elems_len, from, MOD_MODE_CAPWAP);
if (cmod == MOD_NULL) {
cw_dbg(DBG_MSG_ERR,
"Can't find mod to handle connection from %s , discarding message",
sock_addr2str_p(from));
return NULL;
}
struct mod_ac *bmod =
detect_mod(conn, rawmsg, len, elems_len, from, MOD_MODE_BINDINGS);
cw_dbg(DBG_INFO, "Mods deteced: %s,%s", cmod->name, bmod->name);
struct cw_actiondef *ad = mod_cache_add(conn,cmod, bmod);
return ad;
/*
if (bindins_mod) {
cw_dbg(DBG_INFO, "Using mod '%s' to handle CAWPAP for %s", mod->name,
sock_addr2str_p(from));
conn->detected=1;
}
else{
// errno = EAGAIN;
// return -1;
}
mod = detect_mod(conn, rawmsg, len, elems_len, from, MOD_DETECT_BINDINGS);
if (mod) {
cw_dbg(DBG_INFO, "Using bindings '%s' to handle %s", mod->name,
sock_addr2str_p(from));
conn->detected=1;
}
else{
cw_dbg(DBG_MSG_ERR, "Can't detect bindings ... for %s",
sock_addr2str_p(from));
}
return 0;
*/
}
int cw_in_check_generic(struct conn *conn, struct cw_action_in *a, uint8_t * data,
int len,struct sockaddr *from)
{
if (cw_is_request(a->msg_id)){
return cw_in_check_generic_req(conn,a,data,len,from);
}
return cw_in_check_generic_resp(conn,a,data,len,from);
}
static int process_elements(struct conn *conn, uint8_t * rawmsg, int len,
struct sockaddr *from)
{
struct cw_action_in as, *af, *afm;
int offset = cw_get_hdr_msg_offset(rawmsg);
uint8_t *msg_ptr = rawmsg + offset;
int elems_len = cw_get_msg_elems_len(msg_ptr);
int payloadlen = len - offset;
/* pre-check message */
if (payloadlen - 8 != elems_len) {
if (conn->strict_hdr) {
cw_dbg(DBG_MSG_ERR,
"Discarding message from %s, msgelems len=%d, payload len=%d, (Strict CAPWAP) ",
sock_addr2str(&conn->addr), elems_len, payloadlen - 8);
errno = EAGAIN;
return -1;
}
if (elems_len < payloadlen - 8) {
cw_dbg(DBG_RFC,
"Packet from from %s has %d bytes of extra data, ignoring.",
sock_addr2str(&conn->addr), payloadlen - 8 - elems_len);
elems_len = len - 8;
}
if (elems_len > payloadlen - 8) {
cw_dbg(DBG_RFC,
"Packet from from %s has msgelems len of %d bytes, but has only %d bytes of data, truncating.",
sock_addr2str(&conn->addr), elems_len, payloadlen - 8);
elems_len = payloadlen - 8;
}
}
if (!conn->detected) {
//struct mod_ac *mod;
struct cw_actiondef *ad = load_mods(conn, rawmsg, len, elems_len, from);
if (!ad) {
cw_log(LOG_ERR, "Error");
errno = EAGAIN;
return -1;
}
conn->actions = ad;
conn->detected = 1;
}
/* prepare struct for search operation */
as.capwap_state = conn->capwap_state;
as.msg_id = cw_get_msg_id(msg_ptr);
as.vendor_id = 0;
as.elem_id = 0;
as.proto = 0;
/* Search for state/message combination */
afm = cw_actionlist_in_get(conn->actions->in, &as);
if (!afm) {
/* Throw away unexpected response messages */
if (!(as.msg_id & 1)) {
cw_dbg(DBG_MSG_ERR,
"Message type %d (%s) unexpected/illegal in %s State, discarding.",
as.msg_id, cw_strmsg(as.msg_id),
cw_strstate(conn->capwap_state));
errno = EAGAIN;
return -1;
}
/* Request message not found in current state, check if we know
anything else about this message type */
const char *str = cw_strheap_get(conn->actions->strmsg, as.msg_id);
int result_code = 0;
if (str) {
/* Message found, but it was in wrong state */
cw_dbg(DBG_MSG_ERR,
"Message type %d (%s) not allowed in %s State.", as.msg_id,
cw_strmsg(as.msg_id), cw_strstate(as.capwap_state));
result_code = CW_RESULT_MSG_INVALID_IN_CURRENT_STATE;
} else {
/* Message is unknown */
cw_dbg(DBG_MSG_ERR, "Message type %d (%s) unknown.",
as.msg_id, cw_strmsg(as.msg_id),
cw_strstate(as.capwap_state));
result_code = CW_RESULT_MSG_UNRECOGNIZED;
}
cw_send_error_response(conn, rawmsg, result_code);
errno = EAGAIN;
return -1;
}
if (conn->msg_start){
conn->msg_start(conn, afm, rawmsg, len, from);
}
/* Execute start processor for message */
if (afm->start) {
afm->start(conn, afm, rawmsg, len, from);
}
uint8_t *elems_ptr = cw_get_msg_elems_ptr(msg_ptr);
uint8_t *elem;
/* Create an avltree to catch the found mandatory elements */
conn->mand = stravltree_create();
int unrecognized = 0;
/* iterate through message elements */
cw_foreach_elem(elem, elems_ptr, elems_len) {
as.elem_id = cw_get_elem_id(elem);
int elem_len = cw_get_elem_len(elem);
af = cw_actionlist_in_get(conn->actions->in, &as);
if (!af) {
unrecognized++;
cw_dbg(DBG_ELEM_ERR,
"Element %d (%s) not allowed in msg of type %d (%s), ignoring.",
as.elem_id, cw_strelemp(conn->actions, as.elem_id),
as.msg_id, cw_strmsg(as.msg_id));
continue;
}
if (!check_len(conn, af, cw_get_elem_data(elem), elem_len, from)) {
continue;
}
cw_dbg_elem(DBG_ELEM, conn, as.msg_id, as.elem_id, cw_get_elem_data(elem),
elem_len);
int afrc = 1;
if (af->start) {
afrc =
af->start(conn, af, cw_get_elem_data(elem), elem_len, from);
}
if (af->mand && afrc) {
/* add found mandatory message element
to mand list */
stravltree_add(conn->mand, af->item_id);
}
if(conn->elem_end){
afrc = conn->elem_end(conn,af,afrc,cw_get_elem_data(elem), elem_len,from);
}
}
/* all message elements are processed, do now after processing
by calling the "end" function for the message */
int result_code = 0;
int rct = cw_in_check_generic(conn, afm, rawmsg, len, from);
if (rct && conn->strict_capwap)
{
result_code = rct;
}
else {
if (afm->end) {
result_code = afm->end(conn, afm, rawmsg, len, from);
}
if (conn->msg_end){
conn->msg_end(conn, afm, rawmsg, len, from);
}
}
if (unrecognized) {
cw_dbg(DBG_RFC, "Message has %d unrecognized message elements.",
unrecognized);
/* set only resultcode for request messages */
if ( (!result_code) && ((afm->msg_id & 1))) {
if (conn->strict_capwap) {
result_code = CW_RESULT_UNRECOGNIZED_MESSAGE_ELEMENT;
}
}
}
/* if we've got a request message, we always have to send a response message */
if (as.msg_id & 1) {
if (result_code > 0) {
/* the end method gave us an result code>0, so
send an error message */
cw_send_error_response(conn, rawmsg, result_code);
} else if (result_code == 0) {
/* All ok, send regular response message */
cw_send_response(conn, rawmsg, len);
} else {
/* the request message is ignored, no response
will be sent */
errno = EAGAIN;
}
} else {
/*
* Whe have got a response message.
* Put further actions here, if needed.
*/
}
stravltree_destroy(conn->mand);
return result_code;
}
int process_message(struct conn *conn, uint8_t * rawmsg, int rawlen,
struct sockaddr *from)
{
uint8_t *msgptr = rawmsg + cw_get_hdr_msg_offset(rawmsg);
uint32_t type = cw_get_msg_type(msgptr);
if (!(type & 0x1)) {
/* It's a response message, no further examination required. */
return process_elements(conn, rawmsg, rawlen, from);
}
/* It's a request message, check if seqnum is right and if
* we have already sent a response message*/
uint8_t seqnum = cw_get_msg_seqnum(msgptr);
int s1 = conn->last_seqnum_received;
int s2 = seqnum;
int sd = s2 - s1;
if ((sd > 0 && sd < 128) || (sd < 0 && sd < -128) || s1 < 0) {
/* seqnum is ok, normal message processing */
conn->last_seqnum_received = seqnum;
return process_elements(conn, rawmsg, rawlen, from);
}
if (sd != 0) {
cw_dbg(DBG_MSG_ERR,
"Discarding message from %s, old seqnum, seqnum = %d, last seqnum=%d",
sock_addr2str(&conn->addr), s2, s1);
errno = EAGAIN;
return -1;
}
/* the received request message was retransmittet by our peer,
* let's retransmit our response message if we have one*/
cw_dbg(DBG_MSG_ERR,
"Retransmitted request message from %s detected, seqnum=%d, type=%d",
sock_addr2str(&conn->addr), s2, type);
if (cw_get_hdr_msg_type(conn->resp_buffer) - 1 != type) {
cw_dbg(DBG_MSG_ERR,
"No cached response for retransmission, request seqnum=%d,in cache=%d",
s2, conn->resp_msg.type);
errno = EAGAIN;
return -1;
}
cw_dbg(DBG_MSG_ERR, "Retransmitting response message to %s, seqnum=%d",
sock_addr2str(&conn->addr), s2);
// XXX untested
conn_send_msg(conn, conn->resp_buffer);
errno = EAGAIN;
return -1;
}
/*
* Process an incomming CAPWAP packet, assuming the packet is already decrypted
* @param conn conection object
* @param packet pointer to packet data
* @param len lenght of packet data
*/
int conn_process_packet2(struct conn *conn, uint8_t * packet, int len,
struct sockaddr *from)
{
if (len < 8) {
/* packet too short */
cw_dbg(DBG_PKT_ERR,
"Discarding packet from %s, packet too short, len=%d, at least 8 expected.",
sock_addr2str(&conn->addr), len);
errno = EAGAIN;
return -1;
}
int preamble = cw_get_hdr_preamble(packet);
if ((preamble & 0xf0) != (CAPWAP_VERSION << 4)) {
/* wrong version */
cw_dbg(DBG_PKT_ERR,
"Discarding packet from %s, wrong version, version=%d, version %d expected.",
sock_addr2str(&conn->addr), (preamble & 0xf0) >> 4,
CAPWAP_VERSION);
errno = EAGAIN;
return -1;
}
if (preamble & 0xf) {
/* Encrypted data, this shuold never happen here */
cw_dbg(DBG_PKT_ERR,
"Discarding packet from %s, encrypted data after decryption ...",
sock_addr2str(&conn->addr));
errno = EAGAIN;
return -1;
}
int offs = cw_get_hdr_msg_offset(packet);
int payloadlen = len - offs;
if (payloadlen < 0) {
/* Eleminate messages with wrong header size */
cw_dbg(DBG_PKT_ERR,
"Discarding packet from %s, header length (%d) greater than packet len (%d).",
sock_addr2str(&conn->addr), offs, len);
errno = EAGAIN;
return -1;
}
/* Check if Radio MAC is present */
if (cw_get_hdr_flag_m(packet)) {
if (cw_get_hdr_rmac_len(packet) + 8 > offs) {
/* wrong rmac size */
cw_dbg(DBG_PKT_ERR,
"Discarding packet from %s, wrong R-MAC size, size=%d",
sock_addr2str(&conn->addr), *(packet + 8));
errno = EAGAIN;
return -1;
}
}
if (cw_get_hdr_flag_f(packet)) {
/* fragmented, add the packet to fragman */
uint8_t *f;
f = fragman_add(conn->fragman, packet, offs, payloadlen);
if (f == NULL) {
errno = EAGAIN;
return -1;
}
cw_dbg_pkt(DBG_PKT_IN, conn, f + 4, *(uint32_t *) f, from);
cw_dbg_msg(DBG_MSG_IN, conn, f + 4, *(uint32_t *) f, from);
// XXX: Modify fragman to not throw away CAPWAP headers
int rc = conn->process_message(conn, f + 4, *(uint32_t *) f, from);
free(f);
return rc;
}
/* not fragmented, we have a complete message */
cw_dbg_msg(DBG_MSG_IN, conn, packet, len, from);
return conn->process_message(conn, packet, len, from);
}
int conn_process_packet(struct conn *conn, uint8_t * packet, int len,
struct sockaddr *from){
/* show this packet in debug output */
cw_dbg_pkt(DBG_PKT_IN, conn, packet, len, from);
return conn_process_packet2(conn,packet,len,from);
}
int conn_process_data_packet(struct conn *conn, uint8_t * packet, int len,
struct sockaddr *from){
/* show this packet in debug output */
cw_dbg_pkt(DBG_PKT_IN, conn, packet, len, from);
return conn_process_packet2(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;
}