/* $OpenBSD: l2tp_ctrl.c,v 1.27 2022/12/28 21:30:17 jmc Exp $ */ /*- * Copyright (c) 2009 Internet Initiative Japan Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /**@file Control connection processing functions for L2TP LNS */ /* $Id: l2tp_ctrl.c,v 1.27 2022/12/28 21:30:17 jmc Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef USE_LIBSOCKUTIL #include #endif #include "time_utils.h" #include "bytebuf.h" #include "hash.h" #include "debugutil.h" #include "slist.h" #include "l2tp.h" #include "l2tp_local.h" #include "l2tp_subr.h" #include "net_utils.h" #include "version.h" #include "recvfromto.h" #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b)) static int l2tp_ctrl_init(l2tp_ctrl *, l2tpd *, struct sockaddr *, struct sockaddr *, void *); static void l2tp_ctrl_reload(l2tp_ctrl *); static int l2tp_ctrl_send_disconnect_notify(l2tp_ctrl *); static void l2tp_ctrl_timeout(int, short, void *); static int l2tp_ctrl_resend_una_packets(l2tp_ctrl *, bool); static void l2tp_ctrl_destroy_all_calls(l2tp_ctrl *); static int l2tp_ctrl_disconnect_all_calls(l2tp_ctrl *, int); static void l2tp_ctrl_reset_timeout(l2tp_ctrl *); static int l2tp_ctrl_txwin_size(l2tp_ctrl *); static bool l2tp_ctrl_txwin_is_full(l2tp_ctrl *); static bool l2tp_ctrl_in_peer_window(l2tp_ctrl *, uint16_t); static bool l2tp_ctrl_in_our_window(l2tp_ctrl *, uint16_t); static int l2tp_ctrl_recv_SCCRQ(l2tp_ctrl *, u_char *, int, l2tpd *, struct sockaddr *); static int l2tp_ctrl_send_StopCCN(l2tp_ctrl *, int); static int l2tp_ctrl_recv_StopCCN(l2tp_ctrl *, u_char *, int); static void l2tp_ctrl_send_SCCRP(l2tp_ctrl *); static int l2tp_ctrl_send_HELLO(l2tp_ctrl *); static int l2tp_ctrl_send_ZLB(l2tp_ctrl *); static const char *l2tp_ctrl_state_string(l2tp_ctrl *); #ifdef L2TP_CTRL_DEBUG #define L2TP_CTRL_ASSERT(x) ASSERT(x) #define L2TP_CTRL_DBG(x) l2tp_ctrl_log x #else #define L2TP_CTRL_ASSERT(x) #define L2TP_CTRL_DBG(x) #endif /* Sequence # of l2tp_ctrl ID */ static u_int l2tp_ctrl_id_seq = 0; #define SEQ_LT(a,b) ((int16_t)((a) - (b)) < 0) #define SEQ_GT(a,b) ((int16_t)((a) - (b)) > 0) /** * Build instance of {@link ::_l2tp_ctrl L2TP LNS control connection} */ l2tp_ctrl * l2tp_ctrl_create(void) { return calloc(1, sizeof(l2tp_ctrl)); } /** * initialize and startup of {@link ::_l2tp_ctrl L2TP LNS control connection} * instance */ static int l2tp_ctrl_init(l2tp_ctrl *_this, l2tpd *_l2tpd, struct sockaddr *peer, struct sockaddr *sock, void *nat_t_ctx) { int tunid, i; bytebuffer *bytebuf; time_t curr_time; memset(_this, 0, sizeof(l2tp_ctrl)); curr_time = get_monosec(); _this->l2tpd = _l2tpd; _this->state = L2TP_CTRL_STATE_IDLE; _this->last_snd_ctrl = curr_time; slist_init(&_this->call_list); /* seek a free tunnel ID */ i = 0; _this->id = ++l2tp_ctrl_id_seq; for (i = 0, tunid = _this->id; ; i++, tunid++) { tunid &= 0xffff; _this->tunnel_id = l2tp_ctrl_id_seq & 0xffff; if (tunid == 0) continue; if (l2tpd_get_ctrl(_l2tpd, tunid) == NULL) break; if (i > 80000) { /* this must be happen, just log it. */ l2tpd_log(_l2tpd, LOG_ERR, "Too many l2tp controls"); return -1; } } _this->tunnel_id = tunid; L2TP_CTRL_ASSERT(peer != NULL); L2TP_CTRL_ASSERT(sock != NULL); memcpy(&_this->peer, peer, peer->sa_len); memcpy(&_this->sock, sock, sock->sa_len); /* prepare send buffer */ _this->winsz = L2TPD_DEFAULT_SEND_WINSZ; /* * _this->winsz is informed as our receive window size. Also * MIN(_this->winsz, _this->peer_winsiz) is used for the size of * transmit side window. We need winsz * 2 sized buffer so that a * stingy client can fill both of window separately. */ _this->snd_buffercnt = _this->winsz * 2; if ((_this->snd_buffers = calloc(_this->snd_buffercnt, sizeof(bytebuffer *))) == NULL) { l2tpd_log(_l2tpd, LOG_ERR, "calloc() failed in %s(): %m", __func__); goto fail; } for (i = 0; i < _this->snd_buffercnt; i++) { if ((bytebuf = bytebuffer_create(L2TPD_SND_BUFSIZ)) == NULL) { l2tpd_log(_l2tpd, LOG_ERR, "bytebuffer_create() failed in %s(): %m", __func__); goto fail; } _this->snd_buffers[i] = bytebuf; } if ((_this->zlb_buffer = bytebuffer_create(sizeof(struct l2tp_header) + 128)) == NULL) { l2tpd_log(_l2tpd, LOG_ERR, "bytebuffer_create() failed in %s(): %m", __func__); goto fail; } #if defined(USE_LIBSOCKUTIL) || defined(USE_SA_COOKIE) if (nat_t_ctx != NULL) { if ((_this->sa_cookie = malloc( sizeof(struct in_ipsec_sa_cookie))) != NULL) { *(struct in_ipsec_sa_cookie *)_this->sa_cookie = *(struct in_ipsec_sa_cookie *)nat_t_ctx; } else { l2tpd_log(_l2tpd, LOG_ERR, "creating sa_cookie failed: %m"); goto fail; } } #endif _this->hello_interval = L2TP_CTRL_DEFAULT_HELLO_INTERVAL; _this->hello_timeout = L2TP_CTRL_DEFAULT_HELLO_TIMEOUT; _this->hello_io_time = curr_time; /* initialize timeout timer */ l2tp_ctrl_reset_timeout(_this); /* register l2tp context */ l2tpd_add_ctrl(_l2tpd, _this); return 0; fail: l2tp_ctrl_stop(_this, 0); return -1; } /* * setup {@link ::_l2tp_ctrl L2TP LNS control connection} instance */ static void l2tp_ctrl_reload(l2tp_ctrl *_this) { _this->data_use_seq = L2TP_CTRL_CONF(_this)->data_use_seq; if (L2TP_CTRL_CONF(_this)->hello_interval != 0) _this->hello_interval = L2TP_CTRL_CONF(_this)->hello_interval; if (L2TP_CTRL_CONF(_this)->hello_timeout != 0) _this->hello_timeout = L2TP_CTRL_CONF(_this)->hello_timeout; } /* * free {@link ::_l2tp_ctrl L2TP LNS control connection} instance */ void l2tp_ctrl_destroy(l2tp_ctrl *_this) { L2TP_CTRL_ASSERT(_this != NULL); #if defined(USE_LIBSOCKUTIL) || defined(USE_SA_COOKIE) free(_this->sa_cookie); #endif free(_this); } /* * nortify disconnection to peer * * @return 0: all CDN and StopCCN have been sent. * N: if the remaining calls which still not sent CDN exist, * return # of the calls. * -1: when try to send of StopCCN failed. */ static int l2tp_ctrl_send_disconnect_notify(l2tp_ctrl *_this) { int ncalls; L2TP_CTRL_ASSERT(_this != NULL) L2TP_CTRL_ASSERT(_this->state == L2TP_CTRL_STATE_ESTABLISHED || _this->state == L2TP_CTRL_STATE_CLEANUP_WAIT); /* this control is not actively closing or StopCCN have been sent */ if (_this->active_closing == 0) return 0; /* Send CDN all Calls */ ncalls = 0; if (slist_length(&_this->call_list) != 0) { ncalls = l2tp_ctrl_disconnect_all_calls(_this, 0); if (ncalls > 0) { /* * Call the function again to check whether the * sending window is fulled. In case ncalls == 0, * it means we've sent CDN for all calls. */ ncalls = l2tp_ctrl_disconnect_all_calls(_this, 0); } } if (ncalls > 0) return ncalls; if (l2tp_ctrl_send_StopCCN(_this, _this->active_closing) != 0) return -1; _this->active_closing = 0; return 0; } /* * Terminate the control connection * *

* please specify an appropriate value to result( >0 ) for * StopCCN ResultCode AVP, when to sent Active Close (which * require StopCCN sent).

*

* When the return value of this function is zero, the _this * is already released. The lt2p_ctrl process that was bound to it * could not continue. * When the return value of this function is one, the timer * is reset.

* * @return return 0 if terminate process was completed. */ int l2tp_ctrl_stop(l2tp_ctrl *_this, int result) { int i; l2tpd *_l2tpd; L2TP_CTRL_ASSERT(_this != NULL); switch (_this->state) { case L2TP_CTRL_STATE_ESTABLISHED: _this->state = L2TP_CTRL_STATE_CLEANUP_WAIT; if (result > 0) { _this->active_closing = result; l2tp_ctrl_send_disconnect_notify(_this); break; } goto cleanup; default: l2tp_ctrl_log(_this, LOG_DEBUG, "%s() unexpected state=%s", __func__, l2tp_ctrl_state_string(_this)); /* FALLTHROUGH */ case L2TP_CTRL_STATE_WAIT_CTL_CONN: /* FALLTHROUGH */ case L2TP_CTRL_STATE_CLEANUP_WAIT: cleanup: if (slist_length(&_this->call_list) != 0) { if (l2tp_ctrl_disconnect_all_calls(_this, 1) > 0) break; } l2tp_ctrl_log(_this, LOG_NOTICE, "logtype=Finished"); evtimer_del(&_this->ev_timeout); /* free send buffer */ if (_this->snd_buffers != NULL) { for (i = 0; i < _this->snd_buffercnt; i++) bytebuffer_destroy(_this->snd_buffers[i]); free(_this->snd_buffers); _this->snd_buffers = NULL; } if (_this->zlb_buffer != NULL) { bytebuffer_destroy(_this->zlb_buffer); _this->zlb_buffer = NULL; } /* free l2tp_call */ l2tp_ctrl_destroy_all_calls(_this); slist_fini(&_this->call_list); l2tpd_remove_ctrl(_this->l2tpd, _this->tunnel_id); _l2tpd = _this->l2tpd; l2tp_ctrl_destroy(_this); l2tpd_ctrl_finished_notify(_l2tpd); return 0; /* stopped */ } l2tp_ctrl_reset_timeout(_this); return 1; } /* timeout processing */ static void l2tp_ctrl_timeout(int fd, short evtype, void *ctx) { int next_timeout, need_resend; time_t curr_time; l2tp_ctrl *_this; l2tp_call *call; /* * the timer must be reset, when leave this function. * MEMO: l2tp_ctrl_stop() will reset the timer in it. * and please remember that the l2tp_ctrl_stop() may free _this. */ _this = ctx; L2TP_CTRL_ASSERT(_this != NULL); curr_time = get_monosec(); next_timeout = 2; need_resend = 0; if (l2tp_ctrl_txwin_size(_this) > 0) { if (_this->state == L2TP_CTRL_STATE_ESTABLISHED) { if (_this->hello_wait_ack != 0) { /* wait Hello reply */ if (curr_time - _this->hello_io_time >= _this->hello_timeout) { l2tp_ctrl_log(_this, LOG_NOTICE, "timeout waiting ack for hello " "packets."); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); return; } } } else if (curr_time - _this->last_snd_ctrl >= L2TP_CTRL_CTRL_PKT_TIMEOUT) { l2tp_ctrl_log(_this, LOG_NOTICE, "timeout waiting ack for ctrl packets."); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); return; } need_resend = 1; } else { for (slist_itr_first(&_this->call_list); slist_itr_has_next(&_this->call_list);) { call = slist_itr_next(&_this->call_list); if (call->state == L2TP_CALL_STATE_CLEANUP_WAIT) { l2tp_call_destroy(call, 1); slist_itr_remove(&_this->call_list); } } } switch (_this->state) { case L2TP_CTRL_STATE_IDLE: /* * idle: * XXX: never happen in current implementation */ l2tp_ctrl_log(_this, LOG_ERR, "Internal error, timeout on illegal state=idle"); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); break; case L2TP_CTRL_STATE_WAIT_CTL_CONN: /* * wait-ctrl-conn: * if there is no ack for SCCRP, the peer will * resend SCCRQ. however this implementation can * not recognize that the SCCRQ was resent or not. * Therefore, never resent from this side. */ need_resend = 0; break; case L2TP_CTRL_STATE_ESTABLISHED: if (slist_length(&_this->call_list) == 0 && curr_time - _this->last_snd_ctrl >= L2TP_CTRL_WAIT_CALL_TIMEOUT) { if (_this->ncalls == 0) /* fail to receive first call */ l2tp_ctrl_log(_this, LOG_WARNING, "timeout waiting call"); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); return; } if (_this->hello_wait_ack == 0 && _this->hello_interval > 0) { /* send Hello */ if (curr_time - _this->hello_interval >= _this->hello_io_time) { if (l2tp_ctrl_send_HELLO(_this) == 0) /* success */ _this->hello_wait_ack = 1; _this->hello_io_time = curr_time; need_resend = 0; } } break; case L2TP_CTRL_STATE_CLEANUP_WAIT: if (curr_time - _this->last_snd_ctrl >= L2TP_CTRL_CLEANUP_WAIT_TIME) { l2tp_ctrl_log(_this, LOG_NOTICE, "Cleanup timeout state=%d", _this->state); l2tp_ctrl_stop(_this, 0); return; } if (_this->active_closing != 0) l2tp_ctrl_send_disconnect_notify(_this); break; default: l2tp_ctrl_log(_this, LOG_ERR, "Internal error, timeout on illegal state=%d", _this->state); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); return; } /* resend if required */ if (need_resend) l2tp_ctrl_resend_una_packets(_this, true); l2tp_ctrl_reset_timeout(_this); } int l2tp_ctrl_send(l2tp_ctrl *_this, const void *msg, int len) { int rval; #ifdef USE_LIBSOCKUTIL if (_this->sa_cookie != NULL) rval = sendfromto_nat_t(LISTENER_SOCK(_this), msg, len, 0, (struct sockaddr *)&_this->sock, (struct sockaddr *)&_this->peer, _this->sa_cookie); else rval = sendfromto(LISTENER_SOCK(_this), msg, len, 0, (struct sockaddr *)&_this->sock, (struct sockaddr *)&_this->peer); #else #ifdef USE_SA_COOKIE if (_this->sa_cookie != NULL) rval = sendto_nat_t(LISTENER_SOCK(_this), msg, len, 0, (struct sockaddr *)&_this->peer, _this->peer.ss_len, _this->sa_cookie); else #endif rval = sendto(LISTENER_SOCK(_this), msg, len, 0, (struct sockaddr *)&_this->peer, _this->peer.ss_len); #endif return rval; } /* resend una packets */ static int l2tp_ctrl_resend_una_packets(l2tp_ctrl *_this, bool resend) { uint16_t seq; bytebuffer *bytebuf; struct l2tp_header *header; int nsend; nsend = 0; for (seq = _this->snd_una; SEQ_LT(seq, _this->snd_nxt); seq++) { if (!l2tp_ctrl_in_peer_window(_this, seq)) break; if (SEQ_LT(seq, _this->snd_last) && !resend) continue; bytebuf = _this->snd_buffers[seq % _this->snd_buffercnt]; header = bytebuffer_pointer(bytebuf); header->nr = htons(_this->rcv_nxt); _this->snd_lastnr = _this->rcv_nxt; #ifdef L2TP_CTRL_DEBUG if (debuglevel >= 3) { l2tp_ctrl_log(_this, DEBUG_LEVEL_3, "RESEND seq=%u", ntohs(header->ns)); show_hd(debug_get_debugfp(), bytebuffer_pointer(bytebuf), bytebuffer_remaining(bytebuf)); } #endif if (l2tp_ctrl_send(_this, bytebuffer_pointer(bytebuf), bytebuffer_remaining(bytebuf)) < 0) { l2tp_ctrl_log(_this, LOG_ERR, "sendto() failed in %s: %m", __func__); return -1; } nsend++; } return nsend; } /* free all calls */ static void l2tp_ctrl_destroy_all_calls(l2tp_ctrl *_this) { l2tp_call *call; L2TP_CTRL_ASSERT(_this != NULL); while ((call = slist_remove_first(&_this->call_list)) != NULL) l2tp_call_destroy(call, 1); } /* disconnect all calls on the control context * @return return # of calls that is not waiting cleanup. */ static int l2tp_ctrl_disconnect_all_calls(l2tp_ctrl *_this, int drop) { int i, len, ncalls; l2tp_call *call; L2TP_CTRL_ASSERT(_this != NULL); ncalls = 0; len = slist_length(&_this->call_list); for (i = 0; i < len; i++) { call = slist_get(&_this->call_list, i); if (call->state != L2TP_CALL_STATE_CLEANUP_WAIT) { ncalls++; if (l2tp_ctrl_txwin_is_full(_this)) { L2TP_CTRL_DBG((_this, LOG_INFO, "Too many calls. Sending window is not " "enough to send CDN to all clients.")); if (drop) l2tp_call_drop(call); } else l2tp_call_admin_disconnect(call); } } return ncalls; } /* reset timeout */ static void l2tp_ctrl_reset_timeout(l2tp_ctrl *_this) { int intvl; struct timeval tv0; L2TP_CTRL_ASSERT(_this != NULL); if (evtimer_initialized(&_this->ev_timeout)) evtimer_del(&_this->ev_timeout); switch (_this->state) { case L2TP_CTRL_STATE_CLEANUP_WAIT: intvl = 1; break; default: intvl = 2; break; } tv0.tv_usec = 0; tv0.tv_sec = intvl; if (!evtimer_initialized(&_this->ev_timeout)) evtimer_set(&_this->ev_timeout, l2tp_ctrl_timeout, _this); evtimer_add(&_this->ev_timeout, &tv0); } /* * protocols / send and receive */ /* Receive packet */ void l2tp_ctrl_input(l2tpd *_this, int listener_index, struct sockaddr *peer, struct sockaddr *sock, void *nat_t_ctx, u_char *pkt, int pktlen) { int i, len, offsiz, reqlen, is_ctrl; uint16_t mestype; struct l2tp_avp *avp, *avp0; l2tp_ctrl *ctrl; l2tp_call *call; char buf[L2TP_AVP_MAXSIZ], errmsg[256]; time_t curr_time; u_char *pkt0; struct l2tp_header hdr; char hbuf[NI_MAXHOST + NI_MAXSERV + 16]; ctrl = NULL; curr_time = get_monosec(); pkt0 = pkt; L2TP_CTRL_ASSERT(peer->sa_family == sock->sa_family); L2TP_CTRL_ASSERT(peer->sa_family == AF_INET || peer->sa_family == AF_INET6) /* * Parse L2TP Header */ memset(&hdr, 0, sizeof(hdr)); if (pktlen < 2) { snprintf(errmsg, sizeof(errmsg), "a short packet. " "length=%d", pktlen); goto bad_packet; } memcpy(&hdr, pkt, 2); pkt += 2; if (hdr.ver != L2TP_HEADER_VERSION_RFC2661) { /* XXX: only RFC2661 is supported */ snprintf(errmsg, sizeof(errmsg), "Unsupported version at header = %d", hdr.ver); goto bad_packet; } is_ctrl = (hdr.t != 0)? 1 : 0; /* calc required length */ reqlen = 6; /* for Flags, Tunnel-Id, Session-Id field */ if (hdr.l) reqlen += 2; /* for Length field (opt) */ if (hdr.s) reqlen += 4; /* for Ns, Nr field (opt) */ if (hdr.o) reqlen += 2; /* for Offset Size field (opt) */ if (reqlen > pktlen) { snprintf(errmsg, sizeof(errmsg), "a short packet. length=%d", pktlen); goto bad_packet; } if (hdr.l != 0) { GETSHORT(hdr.length, pkt); if (hdr.length > pktlen) { snprintf(errmsg, sizeof(errmsg), "Actual packet size is smaller than the length " "field %d < %d", pktlen, hdr.length); goto bad_packet; } pktlen = hdr.length; /* remove trailing trash */ } GETSHORT(hdr.tunnel_id, pkt); GETSHORT(hdr.session_id, pkt); if (hdr.s != 0) { GETSHORT(hdr.ns, pkt); GETSHORT(hdr.nr, pkt); } if (hdr.o != 0) { GETSHORT(offsiz, pkt); if (pktlen < offsiz) { snprintf(errmsg, sizeof(errmsg), "offset field is bigger than remaining packet " "length %d > %d", offsiz, pktlen); goto bad_packet; } pkt += offsiz; } L2TP_CTRL_ASSERT(pkt - pkt0 == reqlen); pktlen -= (pkt - pkt0); /* cut down the length of header */ ctrl = NULL; memset(buf, 0, sizeof(buf)); mestype = 0; avp = NULL; if (is_ctrl) { avp0 = (struct l2tp_avp *)buf; avp = avp_find_message_type_avp(avp0, pkt, pktlen); if (avp != NULL) mestype = avp->attr_value[0] << 8 | avp->attr_value[1]; } ctrl = l2tpd_get_ctrl(_this, hdr.tunnel_id); if (ctrl == NULL) { /* new control */ if (!is_ctrl) { snprintf(errmsg, sizeof(errmsg), "bad data message: tunnelId=%d is not " "found.", hdr.tunnel_id); goto bad_packet; } if (mestype != L2TP_AVP_MESSAGE_TYPE_SCCRQ) { snprintf(errmsg, sizeof(errmsg), "bad control message: tunnelId=%d is not " "found. mestype=%s", hdr.tunnel_id, avp_mes_type_string(mestype)); goto bad_packet; } if ((ctrl = l2tp_ctrl_create()) == NULL) { l2tp_ctrl_log(ctrl, LOG_ERR, "l2tp_ctrl_create() failed: %m"); goto fail; } if (l2tp_ctrl_init(ctrl, _this, peer, sock, nat_t_ctx) != 0) { l2tp_ctrl_log(ctrl, LOG_ERR, "l2tp_ctrl_start() failed: %m"); goto fail; } ctrl->listener_index = listener_index; l2tp_ctrl_reload(ctrl); } else { /* * treat as an error if src address and port is not * match. (because it is potentially DoS attach) */ int notmatch = 0; if (ctrl->peer.ss_family != peer->sa_family) notmatch = 1; else if (peer->sa_family == AF_INET) { if (SIN(peer)->sin_addr.s_addr != SIN(&ctrl->peer)->sin_addr.s_addr || SIN(peer)->sin_port != SIN(&ctrl->peer)->sin_port) notmatch = 1; } else if (peer->sa_family == AF_INET6) { if (!IN6_ARE_ADDR_EQUAL(&(SIN6(peer)->sin6_addr), &(SIN6(&ctrl->peer)->sin6_addr)) || SIN6(peer)->sin6_port != SIN6(&ctrl->peer)->sin6_port) notmatch = 1; } if (notmatch) { snprintf(errmsg, sizeof(errmsg), "tunnelId=%u is already assigned for %s", hdr.tunnel_id, addrport_tostring( (struct sockaddr *)&ctrl->peer, ctrl->peer.ss_len, hbuf, sizeof(hbuf))); goto bad_packet; } } ctrl->last_rcv = curr_time; call = NULL; if (hdr.session_id != 0) { /* search l2tp_call by Session ID */ /* linear search is enough for this purpose */ len = slist_length(&ctrl->call_list); for (i = 0; i < len; i++) { call = slist_get(&ctrl->call_list, i); if (call->session_id == hdr.session_id) break; call = NULL; } } if (!is_ctrl) { int delayed = 0; /* L2TP data */ if (ctrl->state != L2TP_CTRL_STATE_ESTABLISHED) { l2tp_ctrl_log(ctrl, LOG_WARNING, "Received Data packet in '%s'", l2tp_ctrl_state_string(ctrl)); goto fail; } if (call == NULL) { l2tp_ctrl_log(ctrl, LOG_WARNING, "Received a data packet but it has no call. " "session_id=%u", hdr.session_id); goto fail; } L2TP_CTRL_DBG((ctrl, DEBUG_LEVEL_2, "call=%u RECV ns=%u nr=%u snd_nxt=%u rcv_nxt=%u len=%d", call->id, hdr.ns, hdr.nr, call->snd_nxt, call->rcv_nxt, pktlen)); if (call->state != L2TP_CALL_STATE_ESTABLISHED){ l2tp_ctrl_log(ctrl, LOG_WARNING, "Received a data packet but call is not " "established"); goto fail; } if (hdr.s != 0) { if (SEQ_LT(hdr.ns, call->rcv_nxt)) { if (SEQ_LT(hdr.ns, call->rcv_nxt - L2TP_CALL_DELAY_LIMIT)) { /* sequence number seems to be delayed */ /* XXX: need to log? */ L2TP_CTRL_DBG((ctrl, LOG_DEBUG, "receive a out of sequence " "data packet: %u < %u.", hdr.ns, call->rcv_nxt)); return; } delayed = 1; } else { call->rcv_nxt = hdr.ns + 1; } } l2tp_call_ppp_input(call, pkt, pktlen, delayed); return; } if (hdr.s != 0) { L2TP_CTRL_DBG((ctrl, DEBUG_LEVEL_2, "RECV %s ns=%u nr=%u snd_nxt=%u snd_una=%u rcv_nxt=%u " "len=%d", (is_ctrl)? "C" : "", hdr.ns, hdr.nr, ctrl->snd_nxt, ctrl->snd_una, ctrl->rcv_nxt, pktlen)); if (pktlen <= 0) l2tp_ctrl_log(ctrl, LOG_INFO, "RecvZLB"); if (SEQ_GT(hdr.nr, ctrl->snd_una)) { /* a new ack arrived */ if (SEQ_GT(hdr.nr, ctrl->snd_nxt)) { /* ack is proceeded us */ l2tp_ctrl_log(ctrl, LOG_INFO, "Received message has bad Nr field: " "%u < %u", ctrl->snd_nxt, hdr.nr); goto fail; } ctrl->snd_una = hdr.nr; /* peer window is moved. send out pending packets */ l2tp_ctrl_resend_una_packets(ctrl, false); } if (l2tp_ctrl_txwin_size(ctrl) <= 0) { /* no waiting ack */ if (ctrl->hello_wait_ack != 0) { /* * Reset Hello state, as an ack for the Hello * is received. */ ctrl->hello_wait_ack = 0; ctrl->hello_io_time = curr_time; } switch (ctrl->state) { case L2TP_CTRL_STATE_CLEANUP_WAIT: l2tp_ctrl_stop(ctrl, 0); return; } } if (hdr.ns != ctrl->rcv_nxt) { /* there are remaining packet */ if (l2tp_ctrl_resend_una_packets(ctrl, true) <= 0) { /* resend or sent ZLB */ l2tp_ctrl_send_ZLB(ctrl); } #ifdef L2TP_CTRL_DEBUG if (pktlen != 0) { /* not ZLB */ L2TP_CTRL_DBG((ctrl, LOG_DEBUG, "receive out of sequence %u must be %u. " "mestype=%s", hdr.ns, ctrl->rcv_nxt, avp_mes_type_string(mestype))); } #endif return; } if (pktlen <= 0) return; /* ZLB */ if (!l2tp_ctrl_in_our_window(ctrl, hdr.ns)) { l2tp_ctrl_log(ctrl, LOG_WARNING, "received message is outside of window. " "ns=%d window=%u:%u", hdr.ns, ctrl->snd_lastnr, (uint16_t)(ctrl->snd_lastnr + ctrl->winsz - 1)); return; } ctrl->rcv_nxt++; if (avp == NULL) { l2tpd_log(_this, LOG_WARNING, "bad control message: no message-type AVP."); goto fail; } } /* * state machine (RFC2661 pp. 56-57) */ switch (ctrl->state) { case L2TP_CTRL_STATE_IDLE: switch (mestype) { case L2TP_AVP_MESSAGE_TYPE_SCCRQ: if (l2tp_ctrl_recv_SCCRQ(ctrl, pkt, pktlen, _this, peer) == 0) { /* acceptable */ l2tp_ctrl_send_SCCRP(ctrl); ctrl->state = L2TP_CTRL_STATE_WAIT_CTL_CONN; return; } /* * in case un-acceptable, it was already processed * at l2tcp_ctrl_recv_SCCRQ */ return; case L2TP_AVP_MESSAGE_TYPE_SCCRP: /* * RFC specifies that sent of StopCCN in the state, * However as this implementation only support Passive * open, this packet will not received. */ /* FALLTHROUGH */ case L2TP_AVP_MESSAGE_TYPE_SCCCN: default: break; } goto fsm_fail; case L2TP_CTRL_STATE_WAIT_CTL_CONN: /* Wait-Ctl-Conn */ switch (mestype) { case L2TP_AVP_MESSAGE_TYPE_SCCCN: l2tp_ctrl_log(ctrl, LOG_INFO, "RecvSCCN"); if (l2tp_ctrl_send_ZLB(ctrl) == 0) { ctrl->state = L2TP_CTRL_STATE_ESTABLISHED; } return; case L2TP_AVP_MESSAGE_TYPE_StopCCN: goto receive_stop_ccn; case L2TP_AVP_MESSAGE_TYPE_SCCRQ: case L2TP_AVP_MESSAGE_TYPE_SCCRP: default: break; } break; /* fsm_fail */ case L2TP_CTRL_STATE_ESTABLISHED: /* Established */ switch (mestype) { case L2TP_AVP_MESSAGE_TYPE_SCCCN: case L2TP_AVP_MESSAGE_TYPE_SCCRQ: case L2TP_AVP_MESSAGE_TYPE_SCCRP: break; receive_stop_ccn: case L2TP_AVP_MESSAGE_TYPE_StopCCN: l2tp_ctrl_recv_StopCCN(ctrl, pkt, pktlen); l2tp_ctrl_send_ZLB(ctrl); l2tp_ctrl_stop(ctrl, 0); return; case L2TP_AVP_MESSAGE_TYPE_HELLO: l2tp_ctrl_send_ZLB(ctrl); return; case L2TP_AVP_MESSAGE_TYPE_CDN: case L2TP_AVP_MESSAGE_TYPE_ICRP: case L2TP_AVP_MESSAGE_TYPE_ICCN: if (call == NULL) { l2tp_ctrl_log(ctrl, LOG_INFO, "Unknown call message: %s", avp_mes_type_string(mestype)); goto fail; } /* FALLTHROUGH */ case L2TP_AVP_MESSAGE_TYPE_ICRQ: l2tp_call_recv_packet(ctrl, call, mestype, pkt, pktlen); return; default: break; } break; /* fsm_fail */ case L2TP_CTRL_STATE_CLEANUP_WAIT: if (mestype == L2TP_AVP_MESSAGE_TYPE_StopCCN) { /* * We left ESTABLISHED state, but the peer sent StopCCN. */ goto receive_stop_ccn; } break; /* fsm_fail */ } fsm_fail: /* state machine error */ l2tp_ctrl_log(ctrl, LOG_WARNING, "Received %s in '%s' state", avp_mes_type_string(mestype), l2tp_ctrl_state_string(ctrl)); l2tp_ctrl_stop(ctrl, L2TP_STOP_CCN_RCODE_FSM_ERROR); return; fail: if (ctrl != NULL && mestype != 0) { l2tp_ctrl_log(ctrl, LOG_WARNING, "Received %s in '%s' state", avp_mes_type_string(mestype), l2tp_ctrl_state_string(ctrl)); l2tp_ctrl_stop(ctrl, L2TP_STOP_CCN_RCODE_GENERAL_ERROR); } return; bad_packet: l2tpd_log(_this, LOG_INFO, "Received from=%s: %s", addrport_tostring(peer, peer->sa_len, hbuf, sizeof(hbuf)), errmsg); return; } static int l2tp_ctrl_txwin_size(l2tp_ctrl *_this) { uint16_t sz; sz = _this->snd_nxt - _this->snd_una; L2TP_CTRL_ASSERT(sz <= _this->buffercnt); return sz; } static bool l2tp_ctrl_txwin_is_full(l2tp_ctrl *_this) { return (l2tp_ctrl_txwin_size(_this) >= _this->snd_buffercnt)? 1 : 0; } static bool l2tp_ctrl_in_peer_window(l2tp_ctrl *_this, uint16_t seq) { uint16_t off; int winsz; winsz = MINIMUM(_this->winsz, _this->peer_winsz); off = seq - _this->snd_una; return ((off < winsz)? true : false); } static bool l2tp_ctrl_in_our_window(l2tp_ctrl *_this, uint16_t seq) { uint16_t off; off = seq - _this->snd_lastnr; return ((off < _this->winsz)? true : false); } /* send control packet */ int l2tp_ctrl_send_packet(l2tp_ctrl *_this, int call_id, bytebuffer *bytebuf) { struct l2tp_header *hdr; int rval; time_t curr_time; uint16_t seq; curr_time = get_monosec(); bytebuffer_flip(bytebuf); hdr = (struct l2tp_header *)bytebuffer_pointer(bytebuf); memset(hdr, 0, sizeof(*hdr)); hdr->t = 1; hdr->ver = L2TP_HEADER_VERSION_RFC2661; hdr->l = 1; hdr->length = htons(bytebuffer_remaining(bytebuf)); hdr->tunnel_id = htons(_this->peer_tunnel_id); hdr->session_id = htons(call_id); hdr->s = 1; seq = _this->snd_nxt; hdr->ns = htons(seq); hdr->nr = htons(_this->rcv_nxt); if (bytebuffer_remaining(bytebuf) > sizeof(struct l2tp_header)) /* Not ZLB */ _this->snd_nxt++; if (!l2tp_ctrl_in_peer_window(_this, seq)) return (0); L2TP_CTRL_DBG((_this, DEBUG_LEVEL_2, "SEND C ns=%u nr=%u snd_nxt=%u snd_una=%u rcv_nxt=%u ", ntohs(hdr->ns), htons(hdr->nr), _this->snd_nxt, _this->snd_una, _this->rcv_nxt)); if (L2TP_CTRL_CONF(_this)->ctrl_out_pktdump != 0) { l2tpd_log(_this->l2tpd, LOG_DEBUG, "L2TP Control output packet dump"); show_hd(debug_get_debugfp(), bytebuffer_pointer(bytebuf), bytebuffer_remaining(bytebuf)); } if ((rval = l2tp_ctrl_send(_this, bytebuffer_pointer(bytebuf), bytebuffer_remaining(bytebuf))) < 0) { L2TP_CTRL_DBG((_this, LOG_DEBUG, "sendto() failed: %m")); } _this->snd_lastnr = _this->rcv_nxt; _this->last_snd_ctrl = curr_time; _this->snd_last = seq; return (rval == bytebuffer_remaining(bytebuf))? 0 : 1; } /* * receiver SCCRQ */ static int l2tp_ctrl_recv_SCCRQ(l2tp_ctrl *_this, u_char *pkt, int pktlen, l2tpd *_l2tpd, struct sockaddr *peer) { int avpsz, len, protover, protorev, firmrev, result; struct l2tp_avp *avp; char host[NI_MAXHOST], serv[NI_MAXSERV]; char buf[L2TP_AVP_MAXSIZ], emes[256], hostname[256], vendorname[256]; result = L2TP_STOP_CCN_RCODE_GENERAL_ERROR; strlcpy(hostname, "(no hostname)", sizeof(hostname)); strlcpy(vendorname, "(no vendorname)", sizeof(vendorname)); _this->peer_winsz = 4; /* default is 4 in RFC 2661 */ firmrev = 0; protover = 0; protorev = 0; avp = (struct l2tp_avp *)buf; while (pktlen >= 6 && (avpsz = avp_enum(avp, pkt, pktlen, 1)) > 0) { pkt += avpsz; pktlen -= avpsz; if (avp->vendor_id != 0) { L2TP_CTRL_DBG((_this, LOG_DEBUG, "Received a Vendor-specific AVP vendor-id=%d " "type=%d", avp->vendor_id, avp->attr_type)); continue; } switch (avp->attr_type) { case L2TP_AVP_TYPE_MESSAGE_TYPE: AVP_SIZE_CHECK(avp, ==, 8); continue; case L2TP_AVP_TYPE_PROTOCOL_VERSION: AVP_SIZE_CHECK(avp, ==, 8); protover = avp->attr_value[0]; protorev = avp->attr_value[1]; if (protover != L2TP_RFC2661_VERSION || protorev != L2TP_RFC2661_REVISION) { result = L2TP_STOP_CCN_RCODE_GENERAL_ERROR; snprintf(emes, sizeof(emes), "Peer's protocol version is not supported:" " %d.%d", protover, protorev); goto not_acceptable; } continue; case L2TP_AVP_TYPE_FRAMING_CAPABILITIES: AVP_SIZE_CHECK(avp, ==, 10); if ((avp_get_val32(avp) & L2TP_FRAMING_CAP_FLAGS_SYNC) == 0) { L2TP_CTRL_DBG((_this, LOG_DEBUG, "Peer doesn't " "support synchronous framing")); } continue; case L2TP_AVP_TYPE_BEARER_CAPABILITIES: AVP_SIZE_CHECK(avp, ==, 10); continue; case L2TP_AVP_TYPE_TIE_BREAKER: AVP_SIZE_CHECK(avp, ==, 14); /* * As the implementation never send SCCRQ, * the peer is always winner */ continue; case L2TP_AVP_TYPE_FIRMWARE_REVISION: AVP_SIZE_CHECK(avp, >=, 6); firmrev = avp_get_val16(avp); continue; case L2TP_AVP_TYPE_HOST_NAME: AVP_SIZE_CHECK(avp, >, 4); len = MINIMUM(sizeof(hostname) - 1, avp->length - 6); memcpy(hostname, avp->attr_value, len); hostname[len] = '\0'; continue; case L2TP_AVP_TYPE_VENDOR_NAME: AVP_SIZE_CHECK(avp, >, 4); len = MINIMUM(sizeof(vendorname) - 1, avp->length - 6); memcpy(vendorname, avp->attr_value, len); vendorname[len] = '\0'; continue; case L2TP_AVP_TYPE_ASSINGED_TUNNEL_ID: AVP_SIZE_CHECK(avp, ==, 8); _this->peer_tunnel_id = avp_get_val16(avp); continue; case L2TP_AVP_TYPE_RECV_WINDOW_SIZE: AVP_SIZE_CHECK(avp, ==, 8); _this->peer_winsz = avp_get_val16(avp); continue; } if (avp->is_mandatory) { l2tp_ctrl_log(_this, LOG_WARNING, "Received AVP (%s/%d) is not supported, but it's " "mandatory", avp_attr_type_string(avp->attr_type), avp->attr_type); #ifdef L2TP_CTRL_DEBUG } else { L2TP_CTRL_DBG((_this, LOG_DEBUG, "AVP (%s/%d) is not handled", avp_attr_type_string(avp->attr_type), avp->attr_type)); #endif } } if (getnameinfo((struct sockaddr *)&_this->peer, _this->peer.ss_len, host, sizeof(host), serv, sizeof(serv), NI_NUMERICHOST | NI_NUMERICSERV | NI_DGRAM) != 0) { l2tp_ctrl_log(_this, LOG_ERR, "getnameinfo() failed at %s(): %m", __func__); strlcpy(host, "error", sizeof(host)); strlcpy(serv, "error", sizeof(serv)); } l2tp_ctrl_log(_this, LOG_NOTICE, "logtype=Started RecvSCCRQ " "from=%s:%s/udp tunnel_id=%u/%u protocol=%d.%d winsize=%d " "hostname=%s vendor=%s firm=%04X", host, serv, _this->tunnel_id, _this->peer_tunnel_id, protover, protorev, _this->peer_winsz, hostname, vendorname, firmrev); if (_this->peer_winsz == 0) _this->peer_winsz = 1; return 0; not_acceptable: size_check_failed: l2tp_ctrl_log(_this, LOG_ERR, "Received bad SCCRQ: %s", emes); l2tp_ctrl_stop(_this, result); return 1; } /* * send StopCCN */ static int l2tp_ctrl_send_StopCCN(l2tp_ctrl *_this, int result) { struct l2tp_avp *avp; char buf[L2TP_AVP_MAXSIZ]; bytebuffer *bytebuf; if ((bytebuf = l2tp_ctrl_prepare_snd_buffer(_this, 1)) == NULL) { l2tp_ctrl_log(_this, LOG_ERR, "sending StopCCN failed: no buffer."); return -1; } avp = (struct l2tp_avp *)buf; /* Message Type = StopCCN */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_MESSAGE_TYPE; avp_set_val16(avp, L2TP_AVP_MESSAGE_TYPE_StopCCN); bytebuf_add_avp(bytebuf, avp, 2); /* Assigned Tunnel Id */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_ASSINGED_TUNNEL_ID; avp_set_val16(avp, _this->tunnel_id); bytebuf_add_avp(bytebuf, avp, 2); /* Result Code */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_RESULT_CODE; avp_set_val16(avp, result); bytebuf_add_avp(bytebuf, avp, 2); if (l2tp_ctrl_send_packet(_this, 0, bytebuf) != 0) { l2tp_ctrl_log(_this, LOG_ERR, "sending StopCCN failed"); return - 1; } l2tp_ctrl_log(_this, LOG_INFO, "SendStopCCN result=%d", result); return 0; } /* * Receiver StopCCN */ static int l2tp_ctrl_recv_StopCCN(l2tp_ctrl *_this, u_char *pkt, int pktlen) { int result, error, avpsz, len; uint16_t tunid; struct l2tp_avp *avp; char buf[L2TP_AVP_MAXSIZ + 16], emes[256], pmes[256]; result = 0; error = 0; tunid = 0; pmes[0] = '\0'; avp = (struct l2tp_avp *)buf; while (pktlen >= 6 && (avpsz = avp_enum(avp, pkt, pktlen, 1)) > 0) { pkt += avpsz; pktlen -= avpsz; if (avp->vendor_id != 0) { L2TP_CTRL_DBG((_this, LOG_DEBUG, "Received a Vendor-specific AVP vendor-id=%d " "type=%d", avp->vendor_id, avp->attr_type)); continue; } if (avp->is_hidden != 0) { l2tp_ctrl_log(_this, LOG_WARNING, "Received AVP (%s/%d) is hidden. But we don't " "share secret.", avp_attr_type_string(avp->attr_type), avp->attr_type); if (avp->is_mandatory != 0) { l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL_ERROR | L2TP_ECODE_UNKNOWN_MANDATORY_AVP); return 1; } continue; } switch (avp->attr_type) { case L2TP_AVP_TYPE_MESSAGE_TYPE: AVP_SIZE_CHECK(avp, ==, 8); continue; case L2TP_AVP_TYPE_RESULT_CODE: AVP_SIZE_CHECK(avp, >=, 8); result = avp->attr_value[0] << 8 | avp->attr_value[1]; if (avp->length >= 10) { error = avp->attr_value[2] << 8 | avp->attr_value[3]; len = avp->length - 12; if (len > 0) { len = MINIMUM(len, sizeof(pmes) - 1); memcpy(pmes, &avp->attr_value[4], len); pmes[len] = '\0'; } } continue; case L2TP_AVP_TYPE_ASSINGED_TUNNEL_ID: AVP_SIZE_CHECK(avp, ==, 8); tunid = avp_get_val16(avp); continue; default: if (avp->is_mandatory != 0) { l2tp_ctrl_log(_this, LOG_WARNING, "Received AVP (%s/%d) is not supported, " "but it's mandatory", avp_attr_type_string(avp->attr_type), avp->attr_type); #ifdef L2TP_CTRL_DEBUG } else { L2TP_CTRL_DBG((_this, LOG_DEBUG, "AVP (%s/%d) is not handled", avp_attr_type_string(avp->attr_type), avp->attr_type)); #endif } } } if (result == L2TP_CDN_RCODE_ERROR_CODE && error == L2TP_ECODE_NO_RESOURCE) { /* * Memo: * This state may be happen in following state. * - lots of connect/disconnect by long-running * windows2000, sometimes it fall to this state. * Once it fall to here, connection will fail till * the windows rebooted */ l2tp_ctrl_log(_this, LOG_WARNING, "Peer indicates \"No Resource\" error."); } l2tp_ctrl_log(_this, LOG_INFO, "RecvStopCCN result=%s/%u " "error=%s/%u tunnel_id=%u message=\"%s\"", l2tp_stopccn_rcode_string(result), result, l2tp_ecode_string(error), error, tunid, pmes); return 0; size_check_failed: l2tp_ctrl_log(_this, LOG_ERR, "Received bad StopCCN: %s", emes); return -1; } /* * send SCCRP */ static void l2tp_ctrl_send_SCCRP(l2tp_ctrl *_this) { int len; struct l2tp_avp *avp; char buf[L2TP_AVP_MAXSIZ], hbuf[HOST_NAME_MAX+1]; const char *val; bytebuffer *bytebuf; if ((bytebuf = l2tp_ctrl_prepare_snd_buffer(_this, 1)) == NULL) { l2tp_ctrl_log(_this, LOG_ERR, "sending SCCRP failed: no buffer."); return; } avp = (struct l2tp_avp *)buf; /* Message Type = SCCRP */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_MESSAGE_TYPE; avp_set_val16(avp, L2TP_AVP_MESSAGE_TYPE_SCCRP); bytebuf_add_avp(bytebuf, avp, 2); /* Protocol Version = 1.0 */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_PROTOCOL_VERSION; avp->attr_value[0] = L2TP_RFC2661_VERSION; avp->attr_value[1] = L2TP_RFC2661_REVISION; bytebuf_add_avp(bytebuf, avp, 2); /* Framing Capability = Async */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_FRAMING_CAPABILITIES; avp_set_val32(avp, L2TP_FRAMING_CAP_FLAGS_SYNC); bytebuf_add_avp(bytebuf, avp, 4); /* Host Name */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_HOST_NAME; if ((val = L2TP_CTRL_CONF(_this)->hostname) == NULL) { gethostname(hbuf, sizeof(hbuf)); val = hbuf; } len = strlen(val); memcpy(avp->attr_value, val, len); bytebuf_add_avp(bytebuf, avp, len); /* Assigned Tunnel Id */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_ASSINGED_TUNNEL_ID; avp_set_val16(avp, _this->tunnel_id); bytebuf_add_avp(bytebuf, avp, 2); /* Bearer Capability * This implementation never act as LAC. * memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_BEARER_CAPABILITIES; avp_set_val32(avp, 0); bytebuf_add_avp(bytebuf, avp, 4); */ /* Firmware Revision */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 0; avp->attr_type = L2TP_AVP_TYPE_FIRMWARE_REVISION; avp->attr_value[0] = MAJOR_VERSION; avp->attr_value[1] = MINOR_VERSION; bytebuf_add_avp(bytebuf, avp, 2); /* Vendor Name */ if ((val = L2TP_CTRL_CONF(_this)->vendor_name) != NULL) { memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 0; avp->attr_type = L2TP_AVP_TYPE_VENDOR_NAME; len = strlen(val); memcpy(avp->attr_value, val, len); bytebuf_add_avp(bytebuf, avp, len); } /* Window Size */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_RECV_WINDOW_SIZE; avp_set_val16(avp, _this->winsz); bytebuf_add_avp(bytebuf, avp, 2); if ((l2tp_ctrl_send_packet(_this, 0, bytebuf)) != 0) { l2tp_ctrl_log(_this, LOG_ERR, "sending SCCRP failed"); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); return; } l2tp_ctrl_log(_this, LOG_INFO, "SendSCCRP"); } static int l2tp_ctrl_send_HELLO(l2tp_ctrl *_this) { struct l2tp_avp *avp; char buf[L2TP_AVP_MAXSIZ]; bytebuffer *bytebuf; if ((bytebuf = l2tp_ctrl_prepare_snd_buffer(_this, 1)) == NULL) { l2tp_ctrl_log(_this, LOG_ERR, "sending HELLO failed: no buffer."); return 1; } avp = (struct l2tp_avp *)buf; /* Message Type = HELLO */ memset(avp, 0, sizeof(*avp)); avp->is_mandatory = 1; avp->attr_type = L2TP_AVP_TYPE_MESSAGE_TYPE; avp_set_val16(avp, L2TP_AVP_MESSAGE_TYPE_HELLO); bytebuf_add_avp(bytebuf, avp, 2); if ((l2tp_ctrl_send_packet(_this, 0, bytebuf)) != 0) { l2tp_ctrl_log(_this, LOG_ERR, "sending HELLO failed"); l2tp_ctrl_stop(_this, L2TP_STOP_CCN_RCODE_GENERAL); return 1; } l2tp_ctrl_log(_this, LOG_DEBUG, "SendHELLO"); return 0; } /* Send ZLB */ static int l2tp_ctrl_send_ZLB(l2tp_ctrl *_this) { int loglevel; loglevel = (_this->state == L2TP_CTRL_STATE_ESTABLISHED) ? LOG_DEBUG : LOG_INFO; l2tp_ctrl_log(_this, loglevel, "SendZLB"); bytebuffer_clear(_this->zlb_buffer); bytebuffer_put(_this->zlb_buffer, BYTEBUFFER_PUT_DIRECT, sizeof(struct l2tp_header)); return l2tp_ctrl_send_packet(_this, 0, _this->zlb_buffer); } /* * Utility */ /** * Prepare send buffer * @return return Null when the send buffer exceed Window. */ bytebuffer * l2tp_ctrl_prepare_snd_buffer(l2tp_ctrl *_this, int with_seq) { bytebuffer *bytebuf; L2TP_CTRL_ASSERT(_this != NULL); if (l2tp_ctrl_txwin_is_full(_this)) { l2tp_ctrl_log(_this, LOG_INFO, "sending buffer is full."); return NULL; } bytebuf = _this->snd_buffers[_this->snd_nxt % _this->snd_buffercnt]; bytebuffer_clear(bytebuf); if (with_seq) bytebuffer_put(bytebuf, BYTEBUFFER_PUT_DIRECT, sizeof(struct l2tp_header)); else bytebuffer_put(bytebuf, BYTEBUFFER_PUT_DIRECT, offsetof(struct l2tp_header, ns)); return bytebuf; } /** * return current state as strings */ static inline const char * l2tp_ctrl_state_string(l2tp_ctrl *_this) { switch (_this->state) { case L2TP_CTRL_STATE_IDLE: return "idle"; case L2TP_CTRL_STATE_WAIT_CTL_CONN: return "wait-ctl-conn"; case L2TP_CTRL_STATE_WAIT_CTL_REPLY: return "wait-ctl-reply"; case L2TP_CTRL_STATE_ESTABLISHED: return "established"; case L2TP_CTRL_STATE_CLEANUP_WAIT: return "cleanup-wait"; } return "unknown"; } /* logging with the label of the l2tp instance. */ void l2tp_ctrl_log(l2tp_ctrl *_this, int prio, const char *fmt, ...) { char logbuf[BUFSIZ]; va_list ap; va_start(ap, fmt); #ifdef L2TPD_MULTIPLE snprintf(logbuf, sizeof(logbuf), "l2tpd id=%u ctrl=%u %s", _this->l2tpd->id, _this->id, fmt); #else snprintf(logbuf, sizeof(logbuf), "l2tpd ctrl=%u %s", _this->id, fmt); #endif vlog_printf(prio, logbuf, ap); va_end(ap); }