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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Connection tracking support for PPTP (Point to Point Tunneling Protocol).
- * PPTP is a protocol for creating virtual private networks.
- * It is a specification defined by Microsoft and some vendors
- * working with Microsoft. PPTP is built on top of a modified
- * version of the Internet Generic Routing Encapsulation Protocol.
- * GRE is defined in RFC 1701 and RFC 1702. Documentation of
- * PPTP can be found in RFC 2637
- *
- * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
- *
- * Development of this code funded by Astaro AG (http://www.astaro.com/)
- *
- * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
- *
- * Limitations:
- * - We blindly assume that control connections are always
- * established in PNS->PAC direction. This is a violation
- * of RFC 2637
- * - We can only support one single call within each session
- * TODO:
- * - testing of incoming PPTP calls
- */
- #include <linux/module.h>
- #include <linux/skbuff.h>
- #include <linux/in.h>
- #include <linux/tcp.h>
- #include <net/netfilter/nf_conntrack.h>
- #include <net/netfilter/nf_conntrack_core.h>
- #include <net/netfilter/nf_conntrack_helper.h>
- #include <net/netfilter/nf_conntrack_zones.h>
- #include <linux/netfilter/nf_conntrack_proto_gre.h>
- #include <linux/netfilter/nf_conntrack_pptp.h>
- #define NF_CT_PPTP_VERSION "3.1"
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
- MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
- MODULE_ALIAS("ip_conntrack_pptp");
- MODULE_ALIAS_NFCT_HELPER("pptp");
- static DEFINE_SPINLOCK(nf_pptp_lock);
- int
- (*nf_nat_pptp_hook_outbound)(struct sk_buff *skb,
- struct nf_conn *ct, enum ip_conntrack_info ctinfo,
- unsigned int protoff, struct PptpControlHeader *ctlh,
- union pptp_ctrl_union *pptpReq) __read_mostly;
- EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_outbound);
- int
- (*nf_nat_pptp_hook_inbound)(struct sk_buff *skb,
- struct nf_conn *ct, enum ip_conntrack_info ctinfo,
- unsigned int protoff, struct PptpControlHeader *ctlh,
- union pptp_ctrl_union *pptpReq) __read_mostly;
- EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_inbound);
- void
- (*nf_nat_pptp_hook_exp_gre)(struct nf_conntrack_expect *expect_orig,
- struct nf_conntrack_expect *expect_reply)
- __read_mostly;
- EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_exp_gre);
- void
- (*nf_nat_pptp_hook_expectfn)(struct nf_conn *ct,
- struct nf_conntrack_expect *exp) __read_mostly;
- EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_expectfn);
- #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
- /* PptpControlMessageType names */
- static const char *const pptp_msg_name_array[PPTP_MSG_MAX + 1] = {
- [0] = "UNKNOWN_MESSAGE",
- [PPTP_START_SESSION_REQUEST] = "START_SESSION_REQUEST",
- [PPTP_START_SESSION_REPLY] = "START_SESSION_REPLY",
- [PPTP_STOP_SESSION_REQUEST] = "STOP_SESSION_REQUEST",
- [PPTP_STOP_SESSION_REPLY] = "STOP_SESSION_REPLY",
- [PPTP_ECHO_REQUEST] = "ECHO_REQUEST",
- [PPTP_ECHO_REPLY] = "ECHO_REPLY",
- [PPTP_OUT_CALL_REQUEST] = "OUT_CALL_REQUEST",
- [PPTP_OUT_CALL_REPLY] = "OUT_CALL_REPLY",
- [PPTP_IN_CALL_REQUEST] = "IN_CALL_REQUEST",
- [PPTP_IN_CALL_REPLY] = "IN_CALL_REPLY",
- [PPTP_IN_CALL_CONNECT] = "IN_CALL_CONNECT",
- [PPTP_CALL_CLEAR_REQUEST] = "CALL_CLEAR_REQUEST",
- [PPTP_CALL_DISCONNECT_NOTIFY] = "CALL_DISCONNECT_NOTIFY",
- [PPTP_WAN_ERROR_NOTIFY] = "WAN_ERROR_NOTIFY",
- [PPTP_SET_LINK_INFO] = "SET_LINK_INFO"
- };
- const char *pptp_msg_name(u_int16_t msg)
- {
- if (msg > PPTP_MSG_MAX)
- return pptp_msg_name_array[0];
- return pptp_msg_name_array[msg];
- }
- EXPORT_SYMBOL(pptp_msg_name);
- #endif
- #define SECS *HZ
- #define MINS * 60 SECS
- #define HOURS * 60 MINS
- #define PPTP_GRE_TIMEOUT (10 MINS)
- #define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
- static void pptp_expectfn(struct nf_conn *ct,
- struct nf_conntrack_expect *exp)
- {
- struct net *net = nf_ct_net(ct);
- typeof(nf_nat_pptp_hook_expectfn) nf_nat_pptp_expectfn;
- pr_debug("increasing timeouts\n");
- /* increase timeout of GRE data channel conntrack entry */
- ct->proto.gre.timeout = PPTP_GRE_TIMEOUT;
- ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT;
- /* Can you see how rusty this code is, compared with the pre-2.6.11
- * one? That's what happened to my shiny newnat of 2002 ;( -HW */
- nf_nat_pptp_expectfn = rcu_dereference(nf_nat_pptp_hook_expectfn);
- if (nf_nat_pptp_expectfn && ct->master->status & IPS_NAT_MASK)
- nf_nat_pptp_expectfn(ct, exp);
- else {
- struct nf_conntrack_tuple inv_t;
- struct nf_conntrack_expect *exp_other;
- /* obviously this tuple inversion only works until you do NAT */
- nf_ct_invert_tuple(&inv_t, &exp->tuple);
- pr_debug("trying to unexpect other dir: ");
- nf_ct_dump_tuple(&inv_t);
- exp_other = nf_ct_expect_find_get(net, nf_ct_zone(ct), &inv_t);
- if (exp_other) {
- /* delete other expectation. */
- pr_debug("found\n");
- nf_ct_unexpect_related(exp_other);
- nf_ct_expect_put(exp_other);
- } else {
- pr_debug("not found\n");
- }
- }
- }
- static int destroy_sibling_or_exp(struct net *net, struct nf_conn *ct,
- const struct nf_conntrack_tuple *t)
- {
- const struct nf_conntrack_tuple_hash *h;
- const struct nf_conntrack_zone *zone;
- struct nf_conntrack_expect *exp;
- struct nf_conn *sibling;
- pr_debug("trying to timeout ct or exp for tuple ");
- nf_ct_dump_tuple(t);
- zone = nf_ct_zone(ct);
- h = nf_conntrack_find_get(net, zone, t);
- if (h) {
- sibling = nf_ct_tuplehash_to_ctrack(h);
- pr_debug("setting timeout of conntrack %p to 0\n", sibling);
- sibling->proto.gre.timeout = 0;
- sibling->proto.gre.stream_timeout = 0;
- nf_ct_kill(sibling);
- nf_ct_put(sibling);
- return 1;
- } else {
- exp = nf_ct_expect_find_get(net, zone, t);
- if (exp) {
- pr_debug("unexpect_related of expect %p\n", exp);
- nf_ct_unexpect_related(exp);
- nf_ct_expect_put(exp);
- return 1;
- }
- }
- return 0;
- }
- /* timeout GRE data connections */
- static void pptp_destroy_siblings(struct nf_conn *ct)
- {
- struct net *net = nf_ct_net(ct);
- const struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
- struct nf_conntrack_tuple t;
- nf_ct_gre_keymap_destroy(ct);
- /* try original (pns->pac) tuple */
- memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t));
- t.dst.protonum = IPPROTO_GRE;
- t.src.u.gre.key = ct_pptp_info->pns_call_id;
- t.dst.u.gre.key = ct_pptp_info->pac_call_id;
- if (!destroy_sibling_or_exp(net, ct, &t))
- pr_debug("failed to timeout original pns->pac ct/exp\n");
- /* try reply (pac->pns) tuple */
- memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t));
- t.dst.protonum = IPPROTO_GRE;
- t.src.u.gre.key = ct_pptp_info->pac_call_id;
- t.dst.u.gre.key = ct_pptp_info->pns_call_id;
- if (!destroy_sibling_or_exp(net, ct, &t))
- pr_debug("failed to timeout reply pac->pns ct/exp\n");
- }
- /* expect GRE connections (PNS->PAC and PAC->PNS direction) */
- static int exp_gre(struct nf_conn *ct, __be16 callid, __be16 peer_callid)
- {
- struct nf_conntrack_expect *exp_orig, *exp_reply;
- enum ip_conntrack_dir dir;
- int ret = 1;
- typeof(nf_nat_pptp_hook_exp_gre) nf_nat_pptp_exp_gre;
- exp_orig = nf_ct_expect_alloc(ct);
- if (exp_orig == NULL)
- goto out;
- exp_reply = nf_ct_expect_alloc(ct);
- if (exp_reply == NULL)
- goto out_put_orig;
- /* original direction, PNS->PAC */
- dir = IP_CT_DIR_ORIGINAL;
- nf_ct_expect_init(exp_orig, NF_CT_EXPECT_CLASS_DEFAULT,
- nf_ct_l3num(ct),
- &ct->tuplehash[dir].tuple.src.u3,
- &ct->tuplehash[dir].tuple.dst.u3,
- IPPROTO_GRE, &peer_callid, &callid);
- exp_orig->expectfn = pptp_expectfn;
- /* reply direction, PAC->PNS */
- dir = IP_CT_DIR_REPLY;
- nf_ct_expect_init(exp_reply, NF_CT_EXPECT_CLASS_DEFAULT,
- nf_ct_l3num(ct),
- &ct->tuplehash[dir].tuple.src.u3,
- &ct->tuplehash[dir].tuple.dst.u3,
- IPPROTO_GRE, &callid, &peer_callid);
- exp_reply->expectfn = pptp_expectfn;
- nf_nat_pptp_exp_gre = rcu_dereference(nf_nat_pptp_hook_exp_gre);
- if (nf_nat_pptp_exp_gre && ct->status & IPS_NAT_MASK)
- nf_nat_pptp_exp_gre(exp_orig, exp_reply);
- if (nf_ct_expect_related(exp_orig, 0) != 0)
- goto out_put_both;
- if (nf_ct_expect_related(exp_reply, 0) != 0)
- goto out_unexpect_orig;
- /* Add GRE keymap entries */
- if (nf_ct_gre_keymap_add(ct, IP_CT_DIR_ORIGINAL, &exp_orig->tuple) != 0)
- goto out_unexpect_both;
- if (nf_ct_gre_keymap_add(ct, IP_CT_DIR_REPLY, &exp_reply->tuple) != 0) {
- nf_ct_gre_keymap_destroy(ct);
- goto out_unexpect_both;
- }
- ret = 0;
- out_put_both:
- nf_ct_expect_put(exp_reply);
- out_put_orig:
- nf_ct_expect_put(exp_orig);
- out:
- return ret;
- out_unexpect_both:
- nf_ct_unexpect_related(exp_reply);
- out_unexpect_orig:
- nf_ct_unexpect_related(exp_orig);
- goto out_put_both;
- }
- static int
- pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
- struct PptpControlHeader *ctlh,
- union pptp_ctrl_union *pptpReq,
- unsigned int reqlen,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo)
- {
- struct nf_ct_pptp_master *info = nfct_help_data(ct);
- u_int16_t msg;
- __be16 cid = 0, pcid = 0;
- typeof(nf_nat_pptp_hook_inbound) nf_nat_pptp_inbound;
- msg = ntohs(ctlh->messageType);
- pr_debug("inbound control message %s\n", pptp_msg_name(msg));
- switch (msg) {
- case PPTP_START_SESSION_REPLY:
- /* server confirms new control session */
- if (info->sstate < PPTP_SESSION_REQUESTED)
- goto invalid;
- if (pptpReq->srep.resultCode == PPTP_START_OK)
- info->sstate = PPTP_SESSION_CONFIRMED;
- else
- info->sstate = PPTP_SESSION_ERROR;
- break;
- case PPTP_STOP_SESSION_REPLY:
- /* server confirms end of control session */
- if (info->sstate > PPTP_SESSION_STOPREQ)
- goto invalid;
- if (pptpReq->strep.resultCode == PPTP_STOP_OK)
- info->sstate = PPTP_SESSION_NONE;
- else
- info->sstate = PPTP_SESSION_ERROR;
- break;
- case PPTP_OUT_CALL_REPLY:
- /* server accepted call, we now expect GRE frames */
- if (info->sstate != PPTP_SESSION_CONFIRMED)
- goto invalid;
- if (info->cstate != PPTP_CALL_OUT_REQ &&
- info->cstate != PPTP_CALL_OUT_CONF)
- goto invalid;
- cid = pptpReq->ocack.callID;
- pcid = pptpReq->ocack.peersCallID;
- if (info->pns_call_id != pcid)
- goto invalid;
- pr_debug("%s, CID=%X, PCID=%X\n", pptp_msg_name(msg),
- ntohs(cid), ntohs(pcid));
- if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) {
- info->cstate = PPTP_CALL_OUT_CONF;
- info->pac_call_id = cid;
- exp_gre(ct, cid, pcid);
- } else
- info->cstate = PPTP_CALL_NONE;
- break;
- case PPTP_IN_CALL_REQUEST:
- /* server tells us about incoming call request */
- if (info->sstate != PPTP_SESSION_CONFIRMED)
- goto invalid;
- cid = pptpReq->icreq.callID;
- pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
- info->cstate = PPTP_CALL_IN_REQ;
- info->pac_call_id = cid;
- break;
- case PPTP_IN_CALL_CONNECT:
- /* server tells us about incoming call established */
- if (info->sstate != PPTP_SESSION_CONFIRMED)
- goto invalid;
- if (info->cstate != PPTP_CALL_IN_REP &&
- info->cstate != PPTP_CALL_IN_CONF)
- goto invalid;
- pcid = pptpReq->iccon.peersCallID;
- cid = info->pac_call_id;
- if (info->pns_call_id != pcid)
- goto invalid;
- pr_debug("%s, PCID=%X\n", pptp_msg_name(msg), ntohs(pcid));
- info->cstate = PPTP_CALL_IN_CONF;
- /* we expect a GRE connection from PAC to PNS */
- exp_gre(ct, cid, pcid);
- break;
- case PPTP_CALL_DISCONNECT_NOTIFY:
- /* server confirms disconnect */
- cid = pptpReq->disc.callID;
- pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
- info->cstate = PPTP_CALL_NONE;
- /* untrack this call id, unexpect GRE packets */
- pptp_destroy_siblings(ct);
- break;
- case PPTP_WAN_ERROR_NOTIFY:
- case PPTP_SET_LINK_INFO:
- case PPTP_ECHO_REQUEST:
- case PPTP_ECHO_REPLY:
- /* I don't have to explain these ;) */
- break;
- default:
- goto invalid;
- }
- nf_nat_pptp_inbound = rcu_dereference(nf_nat_pptp_hook_inbound);
- if (nf_nat_pptp_inbound && ct->status & IPS_NAT_MASK)
- return nf_nat_pptp_inbound(skb, ct, ctinfo,
- protoff, ctlh, pptpReq);
- return NF_ACCEPT;
- invalid:
- pr_debug("invalid %s: type=%d cid=%u pcid=%u "
- "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
- pptp_msg_name(msg),
- msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
- ntohs(info->pns_call_id), ntohs(info->pac_call_id));
- return NF_ACCEPT;
- }
- static int
- pptp_outbound_pkt(struct sk_buff *skb, unsigned int protoff,
- struct PptpControlHeader *ctlh,
- union pptp_ctrl_union *pptpReq,
- unsigned int reqlen,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo)
- {
- struct nf_ct_pptp_master *info = nfct_help_data(ct);
- u_int16_t msg;
- __be16 cid = 0, pcid = 0;
- typeof(nf_nat_pptp_hook_outbound) nf_nat_pptp_outbound;
- msg = ntohs(ctlh->messageType);
- pr_debug("outbound control message %s\n", pptp_msg_name(msg));
- switch (msg) {
- case PPTP_START_SESSION_REQUEST:
- /* client requests for new control session */
- if (info->sstate != PPTP_SESSION_NONE)
- goto invalid;
- info->sstate = PPTP_SESSION_REQUESTED;
- break;
- case PPTP_STOP_SESSION_REQUEST:
- /* client requests end of control session */
- info->sstate = PPTP_SESSION_STOPREQ;
- break;
- case PPTP_OUT_CALL_REQUEST:
- /* client initiating connection to server */
- if (info->sstate != PPTP_SESSION_CONFIRMED)
- goto invalid;
- info->cstate = PPTP_CALL_OUT_REQ;
- /* track PNS call id */
- cid = pptpReq->ocreq.callID;
- pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
- info->pns_call_id = cid;
- break;
- case PPTP_IN_CALL_REPLY:
- /* client answers incoming call */
- if (info->cstate != PPTP_CALL_IN_REQ &&
- info->cstate != PPTP_CALL_IN_REP)
- goto invalid;
- cid = pptpReq->icack.callID;
- pcid = pptpReq->icack.peersCallID;
- if (info->pac_call_id != pcid)
- goto invalid;
- pr_debug("%s, CID=%X PCID=%X\n", pptp_msg_name(msg),
- ntohs(cid), ntohs(pcid));
- if (pptpReq->icack.resultCode == PPTP_INCALL_ACCEPT) {
- /* part two of the three-way handshake */
- info->cstate = PPTP_CALL_IN_REP;
- info->pns_call_id = cid;
- } else
- info->cstate = PPTP_CALL_NONE;
- break;
- case PPTP_CALL_CLEAR_REQUEST:
- /* client requests hangup of call */
- if (info->sstate != PPTP_SESSION_CONFIRMED)
- goto invalid;
- /* FUTURE: iterate over all calls and check if
- * call ID is valid. We don't do this without newnat,
- * because we only know about last call */
- info->cstate = PPTP_CALL_CLEAR_REQ;
- break;
- case PPTP_SET_LINK_INFO:
- case PPTP_ECHO_REQUEST:
- case PPTP_ECHO_REPLY:
- /* I don't have to explain these ;) */
- break;
- default:
- goto invalid;
- }
- nf_nat_pptp_outbound = rcu_dereference(nf_nat_pptp_hook_outbound);
- if (nf_nat_pptp_outbound && ct->status & IPS_NAT_MASK)
- return nf_nat_pptp_outbound(skb, ct, ctinfo,
- protoff, ctlh, pptpReq);
- return NF_ACCEPT;
- invalid:
- pr_debug("invalid %s: type=%d cid=%u pcid=%u "
- "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
- pptp_msg_name(msg),
- msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
- ntohs(info->pns_call_id), ntohs(info->pac_call_id));
- return NF_ACCEPT;
- }
- static const unsigned int pptp_msg_size[] = {
- [PPTP_START_SESSION_REQUEST] = sizeof(struct PptpStartSessionRequest),
- [PPTP_START_SESSION_REPLY] = sizeof(struct PptpStartSessionReply),
- [PPTP_STOP_SESSION_REQUEST] = sizeof(struct PptpStopSessionRequest),
- [PPTP_STOP_SESSION_REPLY] = sizeof(struct PptpStopSessionReply),
- [PPTP_OUT_CALL_REQUEST] = sizeof(struct PptpOutCallRequest),
- [PPTP_OUT_CALL_REPLY] = sizeof(struct PptpOutCallReply),
- [PPTP_IN_CALL_REQUEST] = sizeof(struct PptpInCallRequest),
- [PPTP_IN_CALL_REPLY] = sizeof(struct PptpInCallReply),
- [PPTP_IN_CALL_CONNECT] = sizeof(struct PptpInCallConnected),
- [PPTP_CALL_CLEAR_REQUEST] = sizeof(struct PptpClearCallRequest),
- [PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify),
- [PPTP_WAN_ERROR_NOTIFY] = sizeof(struct PptpWanErrorNotify),
- [PPTP_SET_LINK_INFO] = sizeof(struct PptpSetLinkInfo),
- };
- /* track caller id inside control connection, call expect_related */
- static int
- conntrack_pptp_help(struct sk_buff *skb, unsigned int protoff,
- struct nf_conn *ct, enum ip_conntrack_info ctinfo)
- {
- int dir = CTINFO2DIR(ctinfo);
- const struct nf_ct_pptp_master *info = nfct_help_data(ct);
- const struct tcphdr *tcph;
- struct tcphdr _tcph;
- const struct pptp_pkt_hdr *pptph;
- struct pptp_pkt_hdr _pptph;
- struct PptpControlHeader _ctlh, *ctlh;
- union pptp_ctrl_union _pptpReq, *pptpReq;
- unsigned int tcplen = skb->len - protoff;
- unsigned int datalen, reqlen, nexthdr_off;
- int oldsstate, oldcstate;
- int ret;
- u_int16_t msg;
- #if IS_ENABLED(CONFIG_NF_NAT)
- if (!nf_ct_is_confirmed(ct) && (ct->status & IPS_NAT_MASK)) {
- struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
- if (!nat && !nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC))
- return NF_DROP;
- }
- #endif
- /* don't do any tracking before tcp handshake complete */
- if (ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED_REPLY)
- return NF_ACCEPT;
- nexthdr_off = protoff;
- tcph = skb_header_pointer(skb, nexthdr_off, sizeof(_tcph), &_tcph);
- BUG_ON(!tcph);
- nexthdr_off += tcph->doff * 4;
- datalen = tcplen - tcph->doff * 4;
- pptph = skb_header_pointer(skb, nexthdr_off, sizeof(_pptph), &_pptph);
- if (!pptph) {
- pr_debug("no full PPTP header, can't track\n");
- return NF_ACCEPT;
- }
- nexthdr_off += sizeof(_pptph);
- datalen -= sizeof(_pptph);
- /* if it's not a control message we can't do anything with it */
- if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
- ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) {
- pr_debug("not a control packet\n");
- return NF_ACCEPT;
- }
- ctlh = skb_header_pointer(skb, nexthdr_off, sizeof(_ctlh), &_ctlh);
- if (!ctlh)
- return NF_ACCEPT;
- nexthdr_off += sizeof(_ctlh);
- datalen -= sizeof(_ctlh);
- reqlen = datalen;
- msg = ntohs(ctlh->messageType);
- if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
- return NF_ACCEPT;
- if (reqlen > sizeof(*pptpReq))
- reqlen = sizeof(*pptpReq);
- pptpReq = skb_header_pointer(skb, nexthdr_off, reqlen, &_pptpReq);
- if (!pptpReq)
- return NF_ACCEPT;
- oldsstate = info->sstate;
- oldcstate = info->cstate;
- spin_lock_bh(&nf_pptp_lock);
- /* FIXME: We just blindly assume that the control connection is always
- * established from PNS->PAC. However, RFC makes no guarantee */
- if (dir == IP_CT_DIR_ORIGINAL)
- /* client -> server (PNS -> PAC) */
- ret = pptp_outbound_pkt(skb, protoff, ctlh, pptpReq, reqlen, ct,
- ctinfo);
- else
- /* server -> client (PAC -> PNS) */
- ret = pptp_inbound_pkt(skb, protoff, ctlh, pptpReq, reqlen, ct,
- ctinfo);
- pr_debug("sstate: %d->%d, cstate: %d->%d\n",
- oldsstate, info->sstate, oldcstate, info->cstate);
- spin_unlock_bh(&nf_pptp_lock);
- return ret;
- }
- static const struct nf_conntrack_expect_policy pptp_exp_policy = {
- .max_expected = 2,
- .timeout = 5 * 60,
- };
- /* control protocol helper */
- static struct nf_conntrack_helper pptp __read_mostly = {
- .name = "pptp",
- .me = THIS_MODULE,
- .tuple.src.l3num = AF_INET,
- .tuple.src.u.tcp.port = cpu_to_be16(PPTP_CONTROL_PORT),
- .tuple.dst.protonum = IPPROTO_TCP,
- .help = conntrack_pptp_help,
- .destroy = pptp_destroy_siblings,
- .expect_policy = &pptp_exp_policy,
- };
- static int __init nf_conntrack_pptp_init(void)
- {
- NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_pptp_master));
- return nf_conntrack_helper_register(&pptp);
- }
- static void __exit nf_conntrack_pptp_fini(void)
- {
- nf_conntrack_helper_unregister(&pptp);
- }
- module_init(nf_conntrack_pptp_init);
- module_exit(nf_conntrack_pptp_fini);
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