diff options
Diffstat (limited to 'lwip/src/netif/ppp/pppol2tp.c')
| -rw-r--r-- | lwip/src/netif/ppp/pppol2tp.c | 1159 |
1 files changed, 1159 insertions, 0 deletions
diff --git a/lwip/src/netif/ppp/pppol2tp.c b/lwip/src/netif/ppp/pppol2tp.c new file mode 100644 index 0000000..4c4557f --- /dev/null +++ b/lwip/src/netif/ppp/pppol2tp.c @@ -0,0 +1,1159 @@ +/** + * @file + * Network Point to Point Protocol over Layer 2 Tunneling Protocol program file. + * + */ + +/* + * 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. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. + * + * This file is part of the lwIP TCP/IP stack. + * + */ + +/* + * L2TP Support status: + * + * Supported: + * - L2TPv2 (PPP over L2TP, a.k.a. UDP tunnels) + * - LAC + * + * Not supported: + * - LNS (require PPP server support) + * - L2TPv3 ethernet pseudowires + * - L2TPv3 VLAN pseudowire + * - L2TPv3 PPP pseudowires + * - L2TPv3 IP encapsulation + * - L2TPv3 IP pseudowire + * - L2TP tunnel switching - http://tools.ietf.org/html/draft-ietf-l2tpext-tunnel-switching-08 + * - Multiple tunnels per UDP socket, as well as multiple sessions per tunnel + * - Hidden AVPs + */ + +#include "netif/ppp/ppp_opts.h" +#if PPP_SUPPORT && PPPOL2TP_SUPPORT /* don't build if not configured for use in lwipopts.h */ + +#include "lwip/err.h" +#include "lwip/memp.h" +#include "lwip/netif.h" +#include "lwip/udp.h" +#include "lwip/snmp.h" + +#include "netif/ppp/ppp_impl.h" +#include "netif/ppp/lcp.h" +#include "netif/ppp/ipcp.h" +#include "netif/ppp/pppol2tp.h" +#include "netif/ppp/pppcrypt.h" +#include "netif/ppp/magic.h" + +/* Memory pool */ +LWIP_MEMPOOL_DECLARE(PPPOL2TP_PCB, MEMP_NUM_PPPOL2TP_INTERFACES, sizeof(pppol2tp_pcb), "PPPOL2TP_PCB") + +/* callbacks called from PPP core */ +static err_t pppol2tp_write(ppp_pcb *ppp, void *ctx, struct pbuf *p); +static err_t pppol2tp_netif_output(ppp_pcb *ppp, void *ctx, struct pbuf *p, u_short protocol); +static err_t pppol2tp_destroy(ppp_pcb *ppp, void *ctx); /* Destroy a L2TP control block */ +static void pppol2tp_connect(ppp_pcb *ppp, void *ctx); /* Be a LAC, connect to a LNS. */ +static void pppol2tp_disconnect(ppp_pcb *ppp, void *ctx); /* Disconnect */ + + /* Prototypes for procedures local to this file. */ +static void pppol2tp_input(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port); +static void pppol2tp_dispatch_control_packet(pppol2tp_pcb *l2tp, u16_t port, struct pbuf *p, u16_t ns, u16_t nr); +static void pppol2tp_timeout(void *arg); +static void pppol2tp_abort_connect(pppol2tp_pcb *l2tp); +static err_t pppol2tp_send_sccrq(pppol2tp_pcb *l2tp); +static err_t pppol2tp_send_scccn(pppol2tp_pcb *l2tp, u16_t ns); +static err_t pppol2tp_send_icrq(pppol2tp_pcb *l2tp, u16_t ns); +static err_t pppol2tp_send_iccn(pppol2tp_pcb *l2tp, u16_t ns); +static err_t pppol2tp_send_zlb(pppol2tp_pcb *l2tp, u16_t ns, u16_t nr); +static err_t pppol2tp_send_stopccn(pppol2tp_pcb *l2tp, u16_t ns); +static err_t pppol2tp_xmit(pppol2tp_pcb *l2tp, struct pbuf *pb); +static err_t pppol2tp_udp_send(pppol2tp_pcb *l2tp, struct pbuf *pb); + +/* Callbacks structure for PPP core */ +static const struct link_callbacks pppol2tp_callbacks = { + pppol2tp_connect, +#if PPP_SERVER + NULL, +#endif /* PPP_SERVER */ + pppol2tp_disconnect, + pppol2tp_destroy, + pppol2tp_write, + pppol2tp_netif_output, + NULL, + NULL +}; + + +/* Create a new L2TP session. */ +ppp_pcb *pppol2tp_create(struct netif *pppif, + struct netif *netif, const ip_addr_t *ipaddr, u16_t port, + const u8_t *secret, u8_t secret_len, + ppp_link_status_cb_fn link_status_cb, void *ctx_cb) { + ppp_pcb *ppp; + pppol2tp_pcb *l2tp; + struct udp_pcb *udp; +#if !PPPOL2TP_AUTH_SUPPORT + LWIP_UNUSED_ARG(secret); + LWIP_UNUSED_ARG(secret_len); +#endif /* !PPPOL2TP_AUTH_SUPPORT */ + + if (ipaddr == NULL) { + goto ipaddr_check_failed; + } + + l2tp = (pppol2tp_pcb *)LWIP_MEMPOOL_ALLOC(PPPOL2TP_PCB); + if (l2tp == NULL) { + goto memp_malloc_l2tp_failed; + } + + udp = udp_new_ip_type(IP_GET_TYPE(ipaddr)); + if (udp == NULL) { + goto udp_new_failed; + } + udp_recv(udp, pppol2tp_input, l2tp); + + ppp = ppp_new(pppif, &pppol2tp_callbacks, l2tp, link_status_cb, ctx_cb); + if (ppp == NULL) { + goto ppp_new_failed; + } + + memset(l2tp, 0, sizeof(pppol2tp_pcb)); + l2tp->phase = PPPOL2TP_STATE_INITIAL; + l2tp->ppp = ppp; + l2tp->udp = udp; + l2tp->netif = netif; + ip_addr_copy(l2tp->remote_ip, *ipaddr); + l2tp->remote_port = port; +#if PPPOL2TP_AUTH_SUPPORT + l2tp->secret = secret; + l2tp->secret_len = secret_len; +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + return ppp; + +ppp_new_failed: + udp_remove(udp); +udp_new_failed: + LWIP_MEMPOOL_FREE(PPPOL2TP_PCB, l2tp); +memp_malloc_l2tp_failed: +ipaddr_check_failed: + return NULL; +} + +/* Called by PPP core */ +static err_t pppol2tp_write(ppp_pcb *ppp, void *ctx, struct pbuf *p) { + pppol2tp_pcb *l2tp = (pppol2tp_pcb *)ctx; + struct pbuf *ph; /* UDP + L2TP header */ + err_t ret; +#if MIB2_STATS + u16_t tot_len; +#else /* MIB2_STATS */ + LWIP_UNUSED_ARG(ppp); +#endif /* MIB2_STATS */ + + ph = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(PPPOL2TP_OUTPUT_DATA_HEADER_LEN), PBUF_RAM); + if(!ph) { + LINK_STATS_INC(link.memerr); + LINK_STATS_INC(link.proterr); + MIB2_STATS_NETIF_INC(ppp->netif, ifoutdiscards); + pbuf_free(p); + return ERR_MEM; + } + + pbuf_remove_header(ph, PPPOL2TP_OUTPUT_DATA_HEADER_LEN); /* hide L2TP header */ + pbuf_cat(ph, p); +#if MIB2_STATS + tot_len = ph->tot_len; +#endif /* MIB2_STATS */ + + ret = pppol2tp_xmit(l2tp, ph); + if (ret != ERR_OK) { + LINK_STATS_INC(link.err); + MIB2_STATS_NETIF_INC(ppp->netif, ifoutdiscards); + return ret; + } + + MIB2_STATS_NETIF_ADD(ppp->netif, ifoutoctets, (u16_t)tot_len); + MIB2_STATS_NETIF_INC(ppp->netif, ifoutucastpkts); + LINK_STATS_INC(link.xmit); + return ERR_OK; +} + +/* Called by PPP core */ +static err_t pppol2tp_netif_output(ppp_pcb *ppp, void *ctx, struct pbuf *p, u_short protocol) { + pppol2tp_pcb *l2tp = (pppol2tp_pcb *)ctx; + struct pbuf *pb; + u8_t *pl; + err_t err; +#if MIB2_STATS + u16_t tot_len; +#else /* MIB2_STATS */ + LWIP_UNUSED_ARG(ppp); +#endif /* MIB2_STATS */ + + /* @todo: try to use pbuf_header() here! */ + pb = pbuf_alloc(PBUF_TRANSPORT, PPPOL2TP_OUTPUT_DATA_HEADER_LEN + sizeof(protocol), PBUF_RAM); + if(!pb) { + LINK_STATS_INC(link.memerr); + LINK_STATS_INC(link.proterr); + MIB2_STATS_NETIF_INC(ppp->netif, ifoutdiscards); + return ERR_MEM; + } + + pbuf_remove_header(pb, PPPOL2TP_OUTPUT_DATA_HEADER_LEN); + + pl = (u8_t*)pb->payload; + PUTSHORT(protocol, pl); + + pbuf_chain(pb, p); +#if MIB2_STATS + tot_len = pb->tot_len; +#endif /* MIB2_STATS */ + + if( (err = pppol2tp_xmit(l2tp, pb)) != ERR_OK) { + LINK_STATS_INC(link.err); + MIB2_STATS_NETIF_INC(ppp->netif, ifoutdiscards); + return err; + } + + MIB2_STATS_NETIF_ADD(ppp->netif, ifoutoctets, tot_len); + MIB2_STATS_NETIF_INC(ppp->netif, ifoutucastpkts); + LINK_STATS_INC(link.xmit); + return ERR_OK; +} + +/* Destroy a L2TP control block */ +static err_t pppol2tp_destroy(ppp_pcb *ppp, void *ctx) { + pppol2tp_pcb *l2tp = (pppol2tp_pcb *)ctx; + LWIP_UNUSED_ARG(ppp); + + sys_untimeout(pppol2tp_timeout, l2tp); + udp_remove(l2tp->udp); + LWIP_MEMPOOL_FREE(PPPOL2TP_PCB, l2tp); + return ERR_OK; +} + +/* Be a LAC, connect to a LNS. */ +static void pppol2tp_connect(ppp_pcb *ppp, void *ctx) { + err_t err; + pppol2tp_pcb *l2tp = (pppol2tp_pcb *)ctx; + lcp_options *lcp_wo; + lcp_options *lcp_ao; +#if PPP_IPV4_SUPPORT && VJ_SUPPORT + ipcp_options *ipcp_wo; + ipcp_options *ipcp_ao; +#endif /* PPP_IPV4_SUPPORT && VJ_SUPPORT */ + + l2tp->tunnel_port = l2tp->remote_port; + l2tp->our_ns = 0; + l2tp->peer_nr = 0; + l2tp->peer_ns = 0; + l2tp->source_tunnel_id = 0; + l2tp->remote_tunnel_id = 0; + l2tp->source_session_id = 0; + l2tp->remote_session_id = 0; + /* l2tp->*_retried are cleared when used */ + + lcp_wo = &ppp->lcp_wantoptions; + lcp_wo->mru = PPPOL2TP_DEFMRU; + lcp_wo->neg_asyncmap = 0; + lcp_wo->neg_pcompression = 0; + lcp_wo->neg_accompression = 0; + lcp_wo->passive = 0; + lcp_wo->silent = 0; + + lcp_ao = &ppp->lcp_allowoptions; + lcp_ao->mru = PPPOL2TP_DEFMRU; + lcp_ao->neg_asyncmap = 0; + lcp_ao->neg_pcompression = 0; + lcp_ao->neg_accompression = 0; + +#if PPP_IPV4_SUPPORT && VJ_SUPPORT + ipcp_wo = &ppp->ipcp_wantoptions; + ipcp_wo->neg_vj = 0; + ipcp_wo->old_vj = 0; + + ipcp_ao = &ppp->ipcp_allowoptions; + ipcp_ao->neg_vj = 0; + ipcp_ao->old_vj = 0; +#endif /* PPP_IPV4_SUPPORT && VJ_SUPPORT */ + + /* Listen to a random source port, we need to do that instead of using udp_connect() + * because the L2TP LNS might answer with its own random source port (!= 1701) + */ +#if LWIP_IPV6 + if (IP_IS_V6_VAL(l2tp->udp->local_ip)) { + udp_bind(l2tp->udp, IP6_ADDR_ANY, 0); + } else +#endif /* LWIP_IPV6 */ + udp_bind(l2tp->udp, IP_ADDR_ANY, 0); + +#if PPPOL2TP_AUTH_SUPPORT + /* Generate random vector */ + if (l2tp->secret != NULL) { + magic_random_bytes(l2tp->secret_rv, sizeof(l2tp->secret_rv)); + } +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + do { + l2tp->remote_tunnel_id = magic(); + } while(l2tp->remote_tunnel_id == 0); + /* save state, in case we fail to send SCCRQ */ + l2tp->sccrq_retried = 0; + l2tp->phase = PPPOL2TP_STATE_SCCRQ_SENT; + if ((err = pppol2tp_send_sccrq(l2tp)) != 0) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send SCCRQ, error=%d\n", err)); + } + sys_timeout(PPPOL2TP_CONTROL_TIMEOUT, pppol2tp_timeout, l2tp); +} + +/* Disconnect */ +static void pppol2tp_disconnect(ppp_pcb *ppp, void *ctx) { + pppol2tp_pcb *l2tp = (pppol2tp_pcb *)ctx; + + l2tp->our_ns++; + pppol2tp_send_stopccn(l2tp, l2tp->our_ns); + + /* stop any timer, disconnect can be called while initiating is in progress */ + sys_untimeout(pppol2tp_timeout, l2tp); + l2tp->phase = PPPOL2TP_STATE_INITIAL; + ppp_link_end(ppp); /* notify upper layers */ +} + +/* UDP Callback for incoming IPv4 L2TP frames */ +static void pppol2tp_input(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port) { + pppol2tp_pcb *l2tp = (pppol2tp_pcb*)arg; + u16_t hflags, hlen, len=0, tunnel_id=0, session_id=0, ns=0, nr=0, offset=0; + u8_t *inp; + LWIP_UNUSED_ARG(pcb); + + /* we can't unbound a UDP pcb, thus we can still receive UDP frames after the link is closed */ + if (l2tp->phase < PPPOL2TP_STATE_SCCRQ_SENT) { + goto free_and_return; + } + + if (!ip_addr_cmp(&l2tp->remote_ip, addr)) { + goto free_and_return; + } + + /* discard packet if port mismatch, but only if we received a SCCRP */ + if (l2tp->phase > PPPOL2TP_STATE_SCCRQ_SENT && l2tp->tunnel_port != port) { + goto free_and_return; + } + + /* printf("-----------\nL2TP INPUT, %d\n", p->len); */ + + /* L2TP header */ + if (p->len < sizeof(hflags) + sizeof(tunnel_id) + sizeof(session_id) ) { + goto packet_too_short; + } + + inp = (u8_t*)p->payload; + GETSHORT(hflags, inp); + + if (hflags & PPPOL2TP_HEADERFLAG_CONTROL) { + /* check mandatory flags for a control packet */ + if ( (hflags & PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY) != PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY ) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: mandatory header flags for control packet not set\n")); + goto free_and_return; + } + /* check forbidden flags for a control packet */ + if (hflags & PPPOL2TP_HEADERFLAG_CONTROL_FORBIDDEN) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: forbidden header flags for control packet found\n")); + goto free_and_return; + } + } else { + /* check mandatory flags for a data packet */ + if ( (hflags & PPPOL2TP_HEADERFLAG_DATA_MANDATORY) != PPPOL2TP_HEADERFLAG_DATA_MANDATORY) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: mandatory header flags for data packet not set\n")); + goto free_and_return; + } + } + + /* Expected header size */ + hlen = sizeof(hflags) + sizeof(tunnel_id) + sizeof(session_id); + if (hflags & PPPOL2TP_HEADERFLAG_LENGTH) { + hlen += sizeof(len); + } + if (hflags & PPPOL2TP_HEADERFLAG_SEQUENCE) { + hlen += sizeof(ns) + sizeof(nr); + } + if (hflags & PPPOL2TP_HEADERFLAG_OFFSET) { + hlen += sizeof(offset); + } + if (p->len < hlen) { + goto packet_too_short; + } + + if (hflags & PPPOL2TP_HEADERFLAG_LENGTH) { + GETSHORT(len, inp); + if (p->len < len || len < hlen) { + goto packet_too_short; + } + } + GETSHORT(tunnel_id, inp); + GETSHORT(session_id, inp); + if (hflags & PPPOL2TP_HEADERFLAG_SEQUENCE) { + GETSHORT(ns, inp); + GETSHORT(nr, inp); + } + if (hflags & PPPOL2TP_HEADERFLAG_OFFSET) { + GETSHORT(offset, inp) + if (offset > 4096) { /* don't be fooled with large offset which might overflow hlen */ + PPPDEBUG(LOG_DEBUG, ("pppol2tp: strange packet received, offset=%d\n", offset)); + goto free_and_return; + } + hlen += offset; + if (p->len < hlen) { + goto packet_too_short; + } + INCPTR(offset, inp); + } + + /* printf("HLEN = %d\n", hlen); */ + + /* skip L2TP header */ + if (pbuf_remove_header(p, hlen) != 0) { + goto free_and_return; + } + + /* printf("LEN=%d, TUNNEL_ID=%d, SESSION_ID=%d, NS=%d, NR=%d, OFFSET=%d\n", len, tunnel_id, session_id, ns, nr, offset); */ + PPPDEBUG(LOG_DEBUG, ("pppol2tp: input packet, len=%"U16_F", tunnel=%"U16_F", session=%"U16_F", ns=%"U16_F", nr=%"U16_F"\n", + len, tunnel_id, session_id, ns, nr)); + + /* Control packet */ + if (hflags & PPPOL2TP_HEADERFLAG_CONTROL) { + pppol2tp_dispatch_control_packet(l2tp, port, p, ns, nr); + goto free_and_return; + } + + /* Data packet */ + if(l2tp->phase != PPPOL2TP_STATE_DATA) { + goto free_and_return; + } + if(tunnel_id != l2tp->remote_tunnel_id) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: tunnel ID mismatch, assigned=%d, received=%d\n", l2tp->remote_tunnel_id, tunnel_id)); + goto free_and_return; + } + if(session_id != l2tp->remote_session_id) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: session ID mismatch, assigned=%d, received=%d\n", l2tp->remote_session_id, session_id)); + goto free_and_return; + } + /* + * skip address & flags if necessary + * + * RFC 2661 does not specify whether the PPP frame in the L2TP payload should + * have a HDLC header or not. We handle both cases for compatibility. + */ + if (p->len >= 2) { + GETSHORT(hflags, inp); + if (hflags == 0xff03) { + pbuf_remove_header(p, 2); + } + } + /* Dispatch the packet thereby consuming it. */ + ppp_input(l2tp->ppp, p); + return; + +packet_too_short: + PPPDEBUG(LOG_DEBUG, ("pppol2tp: packet too short: %d\n", p->len)); +free_and_return: + pbuf_free(p); +} + +/* L2TP Control packet entry point */ +static void pppol2tp_dispatch_control_packet(pppol2tp_pcb *l2tp, u16_t port, struct pbuf *p, u16_t ns, u16_t nr) { + u8_t *inp; + u16_t avplen, avpflags, vendorid, attributetype, messagetype=0; + err_t err; +#if PPPOL2TP_AUTH_SUPPORT + lwip_md5_context md5_ctx; + u8_t md5_hash[16]; + u8_t challenge_id = 0; +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + /* printf("L2TP CTRL INPUT, ns=%d, nr=%d, len=%d\n", ns, nr, p->len); */ + + /* Drop unexpected packet */ + if (ns != l2tp->peer_ns) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: drop unexpected packet: received NS=%d, expected NS=%d\n", ns, l2tp->peer_ns)); + /* + * In order to ensure that all messages are acknowledged properly + * (particularly in the case of a lost ZLB ACK message), receipt + * of duplicate messages MUST be acknowledged. + * + * In this very special case we Ack a packet we previously received. + * Therefore our NS is the NR we just received. And our NR is the + * NS we just received plus one. + */ + if ((s16_t)(ns - l2tp->peer_ns) < 0) { + pppol2tp_send_zlb(l2tp, nr, ns+1); + } + return; + } + + l2tp->peer_nr = nr; + + /* Handle the special case of the ICCN acknowledge */ + if (l2tp->phase == PPPOL2TP_STATE_ICCN_SENT && (s16_t)(l2tp->peer_nr - l2tp->our_ns) > 0) { + l2tp->phase = PPPOL2TP_STATE_DATA; + sys_untimeout(pppol2tp_timeout, l2tp); + ppp_start(l2tp->ppp); /* notify upper layers */ + } + + /* ZLB packets */ + if (p->tot_len == 0) { + return; + } + /* A ZLB packet does not consume a NS slot thus we don't record the NS value for ZLB packets */ + l2tp->peer_ns = ns+1; + + p = pbuf_coalesce(p, PBUF_RAW); + inp = (u8_t*)p->payload; + /* Decode AVPs */ + while (p->len > 0) { + if (p->len < sizeof(avpflags) + sizeof(vendorid) + sizeof(attributetype) ) { + goto packet_too_short; + } + GETSHORT(avpflags, inp); + avplen = avpflags & PPPOL2TP_AVPHEADERFLAG_LENGTHMASK; + /* printf("AVPLEN = %d\n", avplen); */ + if (p->len < avplen || avplen < sizeof(avpflags) + sizeof(vendorid) + sizeof(attributetype)) { + goto packet_too_short; + } + GETSHORT(vendorid, inp); + GETSHORT(attributetype, inp); + avplen -= sizeof(avpflags) + sizeof(vendorid) + sizeof(attributetype); + + /* Message type must be the first AVP */ + if (messagetype == 0) { + if (attributetype != 0 || vendorid != 0 || avplen != sizeof(messagetype) ) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: message type must be the first AVP\n")); + return; + } + GETSHORT(messagetype, inp); + /* printf("Message type = %d\n", messagetype); */ + switch(messagetype) { + /* Start Control Connection Reply */ + case PPPOL2TP_MESSAGETYPE_SCCRP: + /* Only accept SCCRP packet if we sent a SCCRQ */ + if (l2tp->phase != PPPOL2TP_STATE_SCCRQ_SENT) { + goto send_zlb; + } + break; + /* Incoming Call Reply */ + case PPPOL2TP_MESSAGETYPE_ICRP: + /* Only accept ICRP packet if we sent a IRCQ */ + if (l2tp->phase != PPPOL2TP_STATE_ICRQ_SENT) { + goto send_zlb; + } + break; + /* Stop Control Connection Notification */ + case PPPOL2TP_MESSAGETYPE_STOPCCN: + pppol2tp_send_zlb(l2tp, l2tp->our_ns+1, l2tp->peer_ns); /* Ack the StopCCN before we switch to down state */ + if (l2tp->phase < PPPOL2TP_STATE_DATA) { + pppol2tp_abort_connect(l2tp); + } else if (l2tp->phase == PPPOL2TP_STATE_DATA) { + /* Don't disconnect here, we let the LCP Echo/Reply find the fact + * that PPP session is down. Asking the PPP stack to end the session + * require strict checking about the PPP phase to prevent endless + * disconnection loops. + */ + } + return; + default: + break; + } + goto nextavp; + } + + /* Skip proprietary L2TP extensions */ + if (vendorid != 0) { + goto skipavp; + } + + switch (messagetype) { + /* Start Control Connection Reply */ + case PPPOL2TP_MESSAGETYPE_SCCRP: + switch (attributetype) { + case PPPOL2TP_AVPTYPE_TUNNELID: + if (avplen != sizeof(l2tp->source_tunnel_id) ) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: AVP Assign tunnel ID length check failed\n")); + return; + } + GETSHORT(l2tp->source_tunnel_id, inp); + PPPDEBUG(LOG_DEBUG, ("pppol2tp: Assigned tunnel ID %"U16_F"\n", l2tp->source_tunnel_id)); + goto nextavp; +#if PPPOL2TP_AUTH_SUPPORT + case PPPOL2TP_AVPTYPE_CHALLENGE: + if (avplen == 0) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: Challenge length check failed\n")); + return; + } + if (l2tp->secret == NULL) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: Received challenge from peer and no secret key available\n")); + pppol2tp_abort_connect(l2tp); + return; + } + /* Generate hash of ID, secret, challenge */ + lwip_md5_init(&md5_ctx); + lwip_md5_starts(&md5_ctx); + challenge_id = PPPOL2TP_MESSAGETYPE_SCCCN; + lwip_md5_update(&md5_ctx, &challenge_id, 1); + lwip_md5_update(&md5_ctx, l2tp->secret, l2tp->secret_len); + lwip_md5_update(&md5_ctx, inp, avplen); + lwip_md5_finish(&md5_ctx, l2tp->challenge_hash); + lwip_md5_free(&md5_ctx); + l2tp->send_challenge = 1; + goto skipavp; + case PPPOL2TP_AVPTYPE_CHALLENGERESPONSE: + if (avplen != PPPOL2TP_AVPTYPE_CHALLENGERESPONSE_SIZE) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: AVP Challenge Response length check failed\n")); + return; + } + /* Generate hash of ID, secret, challenge */ + lwip_md5_init(&md5_ctx); + lwip_md5_starts(&md5_ctx); + challenge_id = PPPOL2TP_MESSAGETYPE_SCCRP; + lwip_md5_update(&md5_ctx, &challenge_id, 1); + lwip_md5_update(&md5_ctx, l2tp->secret, l2tp->secret_len); + lwip_md5_update(&md5_ctx, l2tp->secret_rv, sizeof(l2tp->secret_rv)); + lwip_md5_finish(&md5_ctx, md5_hash); + lwip_md5_free(&md5_ctx); + if ( memcmp(inp, md5_hash, sizeof(md5_hash)) ) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: Received challenge response from peer and secret key do not match\n")); + pppol2tp_abort_connect(l2tp); + return; + } + goto skipavp; +#endif /* PPPOL2TP_AUTH_SUPPORT */ + default: + break; + } + break; + /* Incoming Call Reply */ + case PPPOL2TP_MESSAGETYPE_ICRP: + switch (attributetype) { + case PPPOL2TP_AVPTYPE_SESSIONID: + if (avplen != sizeof(l2tp->source_session_id) ) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: AVP Assign session ID length check failed\n")); + return; + } + GETSHORT(l2tp->source_session_id, inp); + PPPDEBUG(LOG_DEBUG, ("pppol2tp: Assigned session ID %"U16_F"\n", l2tp->source_session_id)); + goto nextavp; + default: + break; + } + break; + default: + break; + } + +skipavp: + INCPTR(avplen, inp); +nextavp: + /* printf("AVP Found, vendor=%d, attribute=%d, len=%d\n", vendorid, attributetype, avplen); */ + /* next AVP */ + if (pbuf_remove_header(p, avplen + sizeof(avpflags) + sizeof(vendorid) + sizeof(attributetype)) != 0) { + return; + } + } + + switch(messagetype) { + /* Start Control Connection Reply */ + case PPPOL2TP_MESSAGETYPE_SCCRP: + do { + l2tp->remote_session_id = magic(); + } while(l2tp->remote_session_id == 0); + l2tp->tunnel_port = port; /* LNS server might have chosen its own local port */ + l2tp->icrq_retried = 0; + l2tp->phase = PPPOL2TP_STATE_ICRQ_SENT; + l2tp->our_ns++; + if ((err = pppol2tp_send_scccn(l2tp, l2tp->our_ns)) != 0) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send SCCCN, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + } + l2tp->our_ns++; + if ((err = pppol2tp_send_icrq(l2tp, l2tp->our_ns)) != 0) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send ICRQ, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + } + sys_untimeout(pppol2tp_timeout, l2tp); + sys_timeout(PPPOL2TP_CONTROL_TIMEOUT, pppol2tp_timeout, l2tp); + break; + /* Incoming Call Reply */ + case PPPOL2TP_MESSAGETYPE_ICRP: + l2tp->iccn_retried = 0; + l2tp->phase = PPPOL2TP_STATE_ICCN_SENT; + l2tp->our_ns++; + if ((err = pppol2tp_send_iccn(l2tp, l2tp->our_ns)) != 0) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send ICCN, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + } + sys_untimeout(pppol2tp_timeout, l2tp); + sys_timeout(PPPOL2TP_CONTROL_TIMEOUT, pppol2tp_timeout, l2tp); + break; + /* Unhandled packet, send ZLB ACK */ + default: + goto send_zlb; + } + return; + +send_zlb: + pppol2tp_send_zlb(l2tp, l2tp->our_ns+1, l2tp->peer_ns); + return; +packet_too_short: + PPPDEBUG(LOG_DEBUG, ("pppol2tp: packet too short: %d\n", p->len)); +} + +/* L2TP Timeout handler */ +static void pppol2tp_timeout(void *arg) { + pppol2tp_pcb *l2tp = (pppol2tp_pcb*)arg; + err_t err; + u32_t retry_wait; + + PPPDEBUG(LOG_DEBUG, ("pppol2tp: timeout\n")); + + switch (l2tp->phase) { + case PPPOL2TP_STATE_SCCRQ_SENT: + /* backoff wait */ + if (l2tp->sccrq_retried < 0xff) { + l2tp->sccrq_retried++; + } + if (!l2tp->ppp->settings.persist && l2tp->sccrq_retried >= PPPOL2TP_MAXSCCRQ) { + pppol2tp_abort_connect(l2tp); + return; + } + retry_wait = LWIP_MIN(PPPOL2TP_CONTROL_TIMEOUT * l2tp->sccrq_retried, PPPOL2TP_SLOW_RETRY); + PPPDEBUG(LOG_DEBUG, ("pppol2tp: sccrq_retried=%d\n", l2tp->sccrq_retried)); + if ((err = pppol2tp_send_sccrq(l2tp)) != 0) { + l2tp->sccrq_retried--; + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send SCCRQ, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + } + sys_timeout(retry_wait, pppol2tp_timeout, l2tp); + break; + + case PPPOL2TP_STATE_ICRQ_SENT: + l2tp->icrq_retried++; + if (l2tp->icrq_retried >= PPPOL2TP_MAXICRQ) { + pppol2tp_abort_connect(l2tp); + return; + } + PPPDEBUG(LOG_DEBUG, ("pppol2tp: icrq_retried=%d\n", l2tp->icrq_retried)); + if ((s16_t)(l2tp->peer_nr - l2tp->our_ns) < 0) { /* the SCCCN was not acknowledged */ + if ((err = pppol2tp_send_scccn(l2tp, l2tp->our_ns -1)) != 0) { + l2tp->icrq_retried--; + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send SCCCN, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + sys_timeout(PPPOL2TP_CONTROL_TIMEOUT, pppol2tp_timeout, l2tp); + break; + } + } + if ((err = pppol2tp_send_icrq(l2tp, l2tp->our_ns)) != 0) { + l2tp->icrq_retried--; + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send ICRQ, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + } + sys_timeout(PPPOL2TP_CONTROL_TIMEOUT, pppol2tp_timeout, l2tp); + break; + + case PPPOL2TP_STATE_ICCN_SENT: + l2tp->iccn_retried++; + if (l2tp->iccn_retried >= PPPOL2TP_MAXICCN) { + pppol2tp_abort_connect(l2tp); + return; + } + PPPDEBUG(LOG_DEBUG, ("pppol2tp: iccn_retried=%d\n", l2tp->iccn_retried)); + if ((err = pppol2tp_send_iccn(l2tp, l2tp->our_ns)) != 0) { + l2tp->iccn_retried--; + PPPDEBUG(LOG_DEBUG, ("pppol2tp: failed to send ICCN, error=%d\n", err)); + LWIP_UNUSED_ARG(err); /* if PPPDEBUG is disabled */ + } + sys_timeout(PPPOL2TP_CONTROL_TIMEOUT, pppol2tp_timeout, l2tp); + break; + + default: + return; /* all done, work in peace */ + } +} + +/* Connection attempt aborted */ +static void pppol2tp_abort_connect(pppol2tp_pcb *l2tp) { + PPPDEBUG(LOG_DEBUG, ("pppol2tp: could not establish connection\n")); + l2tp->phase = PPPOL2TP_STATE_INITIAL; + ppp_link_failed(l2tp->ppp); /* notify upper layers */ +} + +/* Initiate a new tunnel */ +static err_t pppol2tp_send_sccrq(pppol2tp_pcb *l2tp) { + struct pbuf *pb; + u8_t *p; + u16_t len; + + /* calculate UDP packet length */ + len = 12 +8 +8 +10 +10 +6+sizeof(PPPOL2TP_HOSTNAME)-1 +6+sizeof(PPPOL2TP_VENDORNAME)-1 +8 +8; +#if PPPOL2TP_AUTH_SUPPORT + if (l2tp->secret != NULL) { + len += 6 + sizeof(l2tp->secret_rv); + } +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + /* allocate a buffer */ + pb = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); + if (pb == NULL) { + return ERR_MEM; + } + LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len); + + p = (u8_t*)pb->payload; + /* fill in pkt */ + /* L2TP control header */ + PUTSHORT(PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY, p); + PUTSHORT(len, p); /* Length */ + PUTSHORT(0, p); /* Tunnel Id */ + PUTSHORT(0, p); /* Session Id */ + PUTSHORT(0, p); /* NS Sequence number - to peer */ + PUTSHORT(0, p); /* NR Sequence number - expected for peer */ + + /* AVP - Message type */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_MESSAGE, p); /* Attribute type: Message Type */ + PUTSHORT(PPPOL2TP_MESSAGETYPE_SCCRQ, p); /* Attribute value: Message type: SCCRQ */ + + /* AVP - L2TP Version */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_VERSION, p); /* Attribute type: Version */ + PUTSHORT(PPPOL2TP_VERSION, p); /* Attribute value: L2TP Version */ + + /* AVP - Framing capabilities */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 10, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_FRAMINGCAPABILITIES, p); /* Attribute type: Framing capabilities */ + PUTLONG(PPPOL2TP_FRAMINGCAPABILITIES, p); /* Attribute value: Framing capabilities */ + + /* AVP - Bearer capabilities */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 10, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_BEARERCAPABILITIES, p); /* Attribute type: Bearer capabilities */ + PUTLONG(PPPOL2TP_BEARERCAPABILITIES, p); /* Attribute value: Bearer capabilities */ + + /* AVP - Host name */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 6+sizeof(PPPOL2TP_HOSTNAME)-1, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_HOSTNAME, p); /* Attribute type: Hostname */ + MEMCPY(p, PPPOL2TP_HOSTNAME, sizeof(PPPOL2TP_HOSTNAME)-1); /* Attribute value: Hostname */ + INCPTR(sizeof(PPPOL2TP_HOSTNAME)-1, p); + + /* AVP - Vendor name */ + PUTSHORT(6+sizeof(PPPOL2TP_VENDORNAME)-1, p); /* len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_VENDORNAME, p); /* Attribute type: Vendor name */ + MEMCPY(p, PPPOL2TP_VENDORNAME, sizeof(PPPOL2TP_VENDORNAME)-1); /* Attribute value: Vendor name */ + INCPTR(sizeof(PPPOL2TP_VENDORNAME)-1, p); + + /* AVP - Assign tunnel ID */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_TUNNELID, p); /* Attribute type: Tunnel ID */ + PUTSHORT(l2tp->remote_tunnel_id, p); /* Attribute value: Tunnel ID */ + + /* AVP - Receive window size */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_RECEIVEWINDOWSIZE, p); /* Attribute type: Receive window size */ + PUTSHORT(PPPOL2TP_RECEIVEWINDOWSIZE, p); /* Attribute value: Receive window size */ + +#if PPPOL2TP_AUTH_SUPPORT + /* AVP - Challenge */ + if (l2tp->secret != NULL) { + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 6 + sizeof(l2tp->secret_rv), p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_CHALLENGE, p); /* Attribute type: Challenge */ + MEMCPY(p, l2tp->secret_rv, sizeof(l2tp->secret_rv)); /* Attribute value: Random vector */ + INCPTR(sizeof(l2tp->secret_rv), p); + } +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + return pppol2tp_udp_send(l2tp, pb); +} + +/* Complete tunnel establishment */ +static err_t pppol2tp_send_scccn(pppol2tp_pcb *l2tp, u16_t ns) { + struct pbuf *pb; + u8_t *p; + u16_t len; + + /* calculate UDP packet length */ + len = 12 +8; +#if PPPOL2TP_AUTH_SUPPORT + if (l2tp->send_challenge) { + len += 6 + sizeof(l2tp->challenge_hash); + } +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + /* allocate a buffer */ + pb = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); + if (pb == NULL) { + return ERR_MEM; + } + LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len); + + p = (u8_t*)pb->payload; + /* fill in pkt */ + /* L2TP control header */ + PUTSHORT(PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY, p); + PUTSHORT(len, p); /* Length */ + PUTSHORT(l2tp->source_tunnel_id, p); /* Tunnel Id */ + PUTSHORT(0, p); /* Session Id */ + PUTSHORT(ns, p); /* NS Sequence number - to peer */ + PUTSHORT(l2tp->peer_ns, p); /* NR Sequence number - expected for peer */ + + /* AVP - Message type */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_MESSAGE, p); /* Attribute type: Message Type */ + PUTSHORT(PPPOL2TP_MESSAGETYPE_SCCCN, p); /* Attribute value: Message type: SCCCN */ + +#if PPPOL2TP_AUTH_SUPPORT + /* AVP - Challenge response */ + if (l2tp->send_challenge) { + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 6 + sizeof(l2tp->challenge_hash), p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_CHALLENGERESPONSE, p); /* Attribute type: Challenge response */ + MEMCPY(p, l2tp->challenge_hash, sizeof(l2tp->challenge_hash)); /* Attribute value: Computed challenge */ + INCPTR(sizeof(l2tp->challenge_hash), p); + } +#endif /* PPPOL2TP_AUTH_SUPPORT */ + + return pppol2tp_udp_send(l2tp, pb); +} + +/* Initiate a new session */ +static err_t pppol2tp_send_icrq(pppol2tp_pcb *l2tp, u16_t ns) { + struct pbuf *pb; + u8_t *p; + u16_t len; + u32_t serialnumber; + + /* calculate UDP packet length */ + len = 12 +8 +8 +10; + + /* allocate a buffer */ + pb = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); + if (pb == NULL) { + return ERR_MEM; + } + LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len); + + p = (u8_t*)pb->payload; + /* fill in pkt */ + /* L2TP control header */ + PUTSHORT(PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY, p); + PUTSHORT(len, p); /* Length */ + PUTSHORT(l2tp->source_tunnel_id, p); /* Tunnel Id */ + PUTSHORT(0, p); /* Session Id */ + PUTSHORT(ns, p); /* NS Sequence number - to peer */ + PUTSHORT(l2tp->peer_ns, p); /* NR Sequence number - expected for peer */ + + /* AVP - Message type */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_MESSAGE, p); /* Attribute type: Message Type */ + PUTSHORT(PPPOL2TP_MESSAGETYPE_ICRQ, p); /* Attribute value: Message type: ICRQ */ + + /* AVP - Assign session ID */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_SESSIONID, p); /* Attribute type: Session ID */ + PUTSHORT(l2tp->remote_session_id, p); /* Attribute value: Session ID */ + + /* AVP - Call Serial Number */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 10, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_CALLSERIALNUMBER, p); /* Attribute type: Serial number */ + serialnumber = magic(); + PUTLONG(serialnumber, p); /* Attribute value: Serial number */ + + return pppol2tp_udp_send(l2tp, pb); +} + +/* Complete tunnel establishment */ +static err_t pppol2tp_send_iccn(pppol2tp_pcb *l2tp, u16_t ns) { + struct pbuf *pb; + u8_t *p; + u16_t len; + + /* calculate UDP packet length */ + len = 12 +8 +10 +10; + + /* allocate a buffer */ + pb = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); + if (pb == NULL) { + return ERR_MEM; + } + LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len); + + p = (u8_t*)pb->payload; + /* fill in pkt */ + /* L2TP control header */ + PUTSHORT(PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY, p); + PUTSHORT(len, p); /* Length */ + PUTSHORT(l2tp->source_tunnel_id, p); /* Tunnel Id */ + PUTSHORT(l2tp->source_session_id, p); /* Session Id */ + PUTSHORT(ns, p); /* NS Sequence number - to peer */ + PUTSHORT(l2tp->peer_ns, p); /* NR Sequence number - expected for peer */ + + /* AVP - Message type */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_MESSAGE, p); /* Attribute type: Message Type */ + PUTSHORT(PPPOL2TP_MESSAGETYPE_ICCN, p); /* Attribute value: Message type: ICCN */ + + /* AVP - Framing type */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 10, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_FRAMINGTYPE, p); /* Attribute type: Framing type */ + PUTLONG(PPPOL2TP_FRAMINGTYPE, p); /* Attribute value: Framing type */ + + /* AVP - TX Connect speed */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 10, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_TXCONNECTSPEED, p); /* Attribute type: TX Connect speed */ + PUTLONG(PPPOL2TP_TXCONNECTSPEED, p); /* Attribute value: TX Connect speed */ + + return pppol2tp_udp_send(l2tp, pb); +} + +/* Send a ZLB ACK packet */ +static err_t pppol2tp_send_zlb(pppol2tp_pcb *l2tp, u16_t ns, u16_t nr) { + struct pbuf *pb; + u8_t *p; + u16_t len; + + /* calculate UDP packet length */ + len = 12; + + /* allocate a buffer */ + pb = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); + if (pb == NULL) { + return ERR_MEM; + } + LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len); + + p = (u8_t*)pb->payload; + /* fill in pkt */ + /* L2TP control header */ + PUTSHORT(PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY, p); + PUTSHORT(len, p); /* Length */ + PUTSHORT(l2tp->source_tunnel_id, p); /* Tunnel Id */ + PUTSHORT(0, p); /* Session Id */ + PUTSHORT(ns, p); /* NS Sequence number - to peer */ + PUTSHORT(nr, p); /* NR Sequence number - expected for peer */ + + return pppol2tp_udp_send(l2tp, pb); +} + +/* Send a StopCCN packet */ +static err_t pppol2tp_send_stopccn(pppol2tp_pcb *l2tp, u16_t ns) { + struct pbuf *pb; + u8_t *p; + u16_t len; + + /* calculate UDP packet length */ + len = 12 +8 +8 +8; + + /* allocate a buffer */ + pb = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); + if (pb == NULL) { + return ERR_MEM; + } + LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len); + + p = (u8_t*)pb->payload; + /* fill in pkt */ + /* L2TP control header */ + PUTSHORT(PPPOL2TP_HEADERFLAG_CONTROL_MANDATORY, p); + PUTSHORT(len, p); /* Length */ + PUTSHORT(l2tp->source_tunnel_id, p); /* Tunnel Id */ + PUTSHORT(0, p); /* Session Id */ + PUTSHORT(ns, p); /* NS Sequence number - to peer */ + PUTSHORT(l2tp->peer_ns, p); /* NR Sequence number - expected for peer */ + + /* AVP - Message type */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_MESSAGE, p); /* Attribute type: Message Type */ + PUTSHORT(PPPOL2TP_MESSAGETYPE_STOPCCN, p); /* Attribute value: Message type: StopCCN */ + + /* AVP - Assign tunnel ID */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_TUNNELID, p); /* Attribute type: Tunnel ID */ + PUTSHORT(l2tp->remote_tunnel_id, p); /* Attribute value: Tunnel ID */ + + /* AVP - Result code */ + PUTSHORT(PPPOL2TP_AVPHEADERFLAG_MANDATORY + 8, p); /* Mandatory flag + len field */ + PUTSHORT(0, p); /* Vendor ID */ + PUTSHORT(PPPOL2TP_AVPTYPE_RESULTCODE, p); /* Attribute type: Result code */ + PUTSHORT(PPPOL2TP_RESULTCODE, p); /* Attribute value: Result code */ + + return pppol2tp_udp_send(l2tp, pb); +} + +static err_t pppol2tp_xmit(pppol2tp_pcb *l2tp, struct pbuf *pb) { + u8_t *p; + + /* make room for L2TP header - should not fail */ + if (pbuf_add_header(pb, PPPOL2TP_OUTPUT_DATA_HEADER_LEN) != 0) { + /* bail out */ + PPPDEBUG(LOG_ERR, ("pppol2tp: pppol2tp_pcb: could not allocate room for L2TP header\n")); + LINK_STATS_INC(link.lenerr); + pbuf_free(pb); + return ERR_BUF; + } + + p = (u8_t*)pb->payload; + PUTSHORT(PPPOL2TP_HEADERFLAG_DATA_MANDATORY, p); + PUTSHORT(l2tp->source_tunnel_id, p); /* Tunnel Id */ + PUTSHORT(l2tp->source_session_id, p); /* Session Id */ + + return pppol2tp_udp_send(l2tp, pb); +} + +static err_t pppol2tp_udp_send(pppol2tp_pcb *l2tp, struct pbuf *pb) { + err_t err; + if (l2tp->netif) { + err = udp_sendto_if(l2tp->udp, pb, &l2tp->remote_ip, l2tp->tunnel_port, l2tp->netif); + } else { + err = udp_sendto(l2tp->udp, pb, &l2tp->remote_ip, l2tp->tunnel_port); + } + pbuf_free(pb); + return err; +} + +#endif /* PPP_SUPPORT && PPPOL2TP_SUPPORT */ |