| /* |
| * ip_conntrack_pptp.c - Version 3.0 |
| * |
| * Connection tracking support for PPTP (Point to Point Tunneling Protocol). |
| * PPTP is a 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/) |
| * |
| * Limitations: |
| * - We blindly assume that control connections are always |
| * established in PNS->PAC direction. This is a violation |
| * of RFFC2673 |
| * - We can only support one single call within each session |
| * |
| * TODO: |
| * - testing of incoming PPTP calls |
| * |
| * Changes: |
| * 2002-02-05 - Version 1.3 |
| * - Call ip_conntrack_unexpect_related() from |
| * pptp_destroy_siblings() to destroy expectations in case |
| * CALL_DISCONNECT_NOTIFY or tcp fin packet was seen |
| * (Philip Craig <philipc@snapgear.com>) |
| * - Add Version information at module loadtime |
| * 2002-02-10 - Version 1.6 |
| * - move to C99 style initializers |
| * - remove second expectation if first arrives |
| * 2004-10-22 - Version 2.0 |
| * - merge Mandrake's 2.6.x port with recent 2.6.x API changes |
| * - fix lots of linear skb assumptions from Mandrake's port |
| * 2005-06-10 - Version 2.1 |
| * - use ip_conntrack_expect_free() instead of kfree() on the |
| * expect's (which are from the slab for quite some time) |
| * 2005-06-10 - Version 3.0 |
| * - port helper to post-2.6.11 API changes, |
| * funded by Oxcoda NetBox Blue (http://www.netboxblue.com/) |
| * 2005-07-30 - Version 3.1 |
| * - port helper to 2.6.13 API changes |
| * |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/module.h> |
| #include <linux/netfilter.h> |
| #include <linux/ip.h> |
| #include <net/checksum.h> |
| #include <net/tcp.h> |
| |
| #include <linux/netfilter_ipv4/ip_conntrack.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_core.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_helper.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_pptp.h> |
| |
| #define IP_CT_PPTP_VERSION "3.1" |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); |
| MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP"); |
| |
| static DEFINE_SPINLOCK(ip_pptp_lock); |
| |
| int |
| (*ip_nat_pptp_hook_outbound)(struct sk_buff **pskb, |
| struct ip_conntrack *ct, |
| enum ip_conntrack_info ctinfo, |
| struct PptpControlHeader *ctlh, |
| union pptp_ctrl_union *pptpReq); |
| |
| int |
| (*ip_nat_pptp_hook_inbound)(struct sk_buff **pskb, |
| struct ip_conntrack *ct, |
| enum ip_conntrack_info ctinfo, |
| struct PptpControlHeader *ctlh, |
| union pptp_ctrl_union *pptpReq); |
| |
| int |
| (*ip_nat_pptp_hook_exp_gre)(struct ip_conntrack_expect *expect_orig, |
| struct ip_conntrack_expect *expect_reply); |
| |
| void |
| (*ip_nat_pptp_hook_expectfn)(struct ip_conntrack *ct, |
| struct ip_conntrack_expect *exp); |
| |
| #if 0 |
| /* PptpControlMessageType names */ |
| const char *pptp_msg_name[] = { |
| "UNKNOWN_MESSAGE", |
| "START_SESSION_REQUEST", |
| "START_SESSION_REPLY", |
| "STOP_SESSION_REQUEST", |
| "STOP_SESSION_REPLY", |
| "ECHO_REQUEST", |
| "ECHO_REPLY", |
| "OUT_CALL_REQUEST", |
| "OUT_CALL_REPLY", |
| "IN_CALL_REQUEST", |
| "IN_CALL_REPLY", |
| "IN_CALL_CONNECT", |
| "CALL_CLEAR_REQUEST", |
| "CALL_DISCONNECT_NOTIFY", |
| "WAN_ERROR_NOTIFY", |
| "SET_LINK_INFO" |
| }; |
| EXPORT_SYMBOL(pptp_msg_name); |
| #define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args) |
| #else |
| #define DEBUGP(format, args...) |
| #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 ip_conntrack *ct, |
| struct ip_conntrack_expect *exp) |
| { |
| DEBUGP("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 */ |
| |
| if (!ip_nat_pptp_hook_expectfn) { |
| struct ip_conntrack_tuple inv_t; |
| struct ip_conntrack_expect *exp_other; |
| |
| /* obviously this tuple inversion only works until you do NAT */ |
| invert_tuplepr(&inv_t, &exp->tuple); |
| DEBUGP("trying to unexpect other dir: "); |
| DUMP_TUPLE(&inv_t); |
| |
| exp_other = ip_conntrack_expect_find(&inv_t); |
| if (exp_other) { |
| /* delete other expectation. */ |
| DEBUGP("found\n"); |
| ip_conntrack_unexpect_related(exp_other); |
| ip_conntrack_expect_put(exp_other); |
| } else { |
| DEBUGP("not found\n"); |
| } |
| } else { |
| /* we need more than simple inversion */ |
| ip_nat_pptp_hook_expectfn(ct, exp); |
| } |
| } |
| |
| static int destroy_sibling_or_exp(const struct ip_conntrack_tuple *t) |
| { |
| struct ip_conntrack_tuple_hash *h; |
| struct ip_conntrack_expect *exp; |
| |
| DEBUGP("trying to timeout ct or exp for tuple "); |
| DUMP_TUPLE(t); |
| |
| h = ip_conntrack_find_get(t, NULL); |
| if (h) { |
| struct ip_conntrack *sibling = tuplehash_to_ctrack(h); |
| DEBUGP("setting timeout of conntrack %p to 0\n", sibling); |
| sibling->proto.gre.timeout = 0; |
| sibling->proto.gre.stream_timeout = 0; |
| if (del_timer(&sibling->timeout)) |
| sibling->timeout.function((unsigned long)sibling); |
| ip_conntrack_put(sibling); |
| return 1; |
| } else { |
| exp = ip_conntrack_expect_find(t); |
| if (exp) { |
| DEBUGP("unexpect_related of expect %p\n", exp); |
| ip_conntrack_unexpect_related(exp); |
| ip_conntrack_expect_put(exp); |
| return 1; |
| } |
| } |
| |
| return 0; |
| } |
| |
| |
| /* timeout GRE data connections */ |
| static void pptp_destroy_siblings(struct ip_conntrack *ct) |
| { |
| struct ip_conntrack_tuple t; |
| |
| /* Since ct->sibling_list has literally rusted away in 2.6.11, |
| * we now need another way to find out about our sibling |
| * contrack and expects... -HW */ |
| |
| /* 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 = htons(ct->help.ct_pptp_info.pns_call_id); |
| t.dst.u.gre.key = htons(ct->help.ct_pptp_info.pac_call_id); |
| |
| if (!destroy_sibling_or_exp(&t)) |
| DEBUGP("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 = htons(ct->help.ct_pptp_info.pac_call_id); |
| t.dst.u.gre.key = htons(ct->help.ct_pptp_info.pns_call_id); |
| |
| if (!destroy_sibling_or_exp(&t)) |
| DEBUGP("failed to timeout reply pac->pns ct/exp\n"); |
| } |
| |
| /* expect GRE connections (PNS->PAC and PAC->PNS direction) */ |
| static inline int |
| exp_gre(struct ip_conntrack *master, |
| u_int32_t seq, |
| __be16 callid, |
| __be16 peer_callid) |
| { |
| struct ip_conntrack_tuple inv_tuple; |
| struct ip_conntrack_tuple exp_tuples[] = { |
| /* tuple in original direction, PNS->PAC */ |
| { .src = { .ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip, |
| .u = { .gre = { .key = peer_callid } } |
| }, |
| .dst = { .ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip, |
| .u = { .gre = { .key = callid } }, |
| .protonum = IPPROTO_GRE |
| }, |
| }, |
| /* tuple in reply direction, PAC->PNS */ |
| { .src = { .ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip, |
| .u = { .gre = { .key = callid } } |
| }, |
| .dst = { .ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip, |
| .u = { .gre = { .key = peer_callid } }, |
| .protonum = IPPROTO_GRE |
| }, |
| } |
| }; |
| struct ip_conntrack_expect *exp_orig, *exp_reply; |
| int ret = 1; |
| |
| exp_orig = ip_conntrack_expect_alloc(master); |
| if (exp_orig == NULL) |
| goto out; |
| |
| exp_reply = ip_conntrack_expect_alloc(master); |
| if (exp_reply == NULL) |
| goto out_put_orig; |
| |
| memcpy(&exp_orig->tuple, &exp_tuples[0], sizeof(exp_orig->tuple)); |
| |
| exp_orig->mask.src.ip = 0xffffffff; |
| exp_orig->mask.src.u.all = 0; |
| exp_orig->mask.dst.u.all = 0; |
| exp_orig->mask.dst.u.gre.key = htons(0xffff); |
| exp_orig->mask.dst.ip = 0xffffffff; |
| exp_orig->mask.dst.protonum = 0xff; |
| |
| exp_orig->master = master; |
| exp_orig->expectfn = pptp_expectfn; |
| exp_orig->flags = 0; |
| |
| /* both expectations are identical apart from tuple */ |
| memcpy(exp_reply, exp_orig, sizeof(*exp_reply)); |
| memcpy(&exp_reply->tuple, &exp_tuples[1], sizeof(exp_reply->tuple)); |
| |
| if (ip_nat_pptp_hook_exp_gre) |
| ret = ip_nat_pptp_hook_exp_gre(exp_orig, exp_reply); |
| else { |
| |
| DEBUGP("calling expect_related PNS->PAC"); |
| DUMP_TUPLE(&exp_orig->tuple); |
| |
| if (ip_conntrack_expect_related(exp_orig) != 0) { |
| DEBUGP("cannot expect_related()\n"); |
| goto out_put_both; |
| } |
| |
| DEBUGP("calling expect_related PAC->PNS"); |
| DUMP_TUPLE(&exp_reply->tuple); |
| |
| if (ip_conntrack_expect_related(exp_reply) != 0) { |
| DEBUGP("cannot expect_related()\n"); |
| goto out_unexpect_orig; |
| } |
| |
| /* Add GRE keymap entries */ |
| if (ip_ct_gre_keymap_add(master, &exp_reply->tuple, 0) != 0) { |
| DEBUGP("cannot keymap_add() exp\n"); |
| goto out_unexpect_both; |
| } |
| |
| invert_tuplepr(&inv_tuple, &exp_reply->tuple); |
| if (ip_ct_gre_keymap_add(master, &inv_tuple, 1) != 0) { |
| ip_ct_gre_keymap_destroy(master); |
| DEBUGP("cannot keymap_add() exp_inv\n"); |
| goto out_unexpect_both; |
| } |
| ret = 0; |
| } |
| |
| out_put_both: |
| ip_conntrack_expect_put(exp_reply); |
| out_put_orig: |
| ip_conntrack_expect_put(exp_orig); |
| out: |
| return ret; |
| |
| out_unexpect_both: |
| ip_conntrack_unexpect_related(exp_reply); |
| out_unexpect_orig: |
| ip_conntrack_unexpect_related(exp_orig); |
| goto out_put_both; |
| } |
| |
| static inline int |
| pptp_inbound_pkt(struct sk_buff **pskb, |
| struct tcphdr *tcph, |
| unsigned int nexthdr_off, |
| unsigned int datalen, |
| struct ip_conntrack *ct, |
| enum ip_conntrack_info ctinfo) |
| { |
| struct PptpControlHeader _ctlh, *ctlh; |
| unsigned int reqlen; |
| union pptp_ctrl_union _pptpReq, *pptpReq; |
| struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
| u_int16_t msg; |
| __be16 *cid, *pcid; |
| u_int32_t seq; |
| |
| ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh); |
| if (!ctlh) { |
| DEBUGP("error during skb_header_pointer\n"); |
| return NF_ACCEPT; |
| } |
| nexthdr_off += sizeof(_ctlh); |
| datalen -= sizeof(_ctlh); |
| |
| reqlen = datalen; |
| if (reqlen > sizeof(*pptpReq)) |
| reqlen = sizeof(*pptpReq); |
| pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq); |
| if (!pptpReq) { |
| DEBUGP("error during skb_header_pointer\n"); |
| return NF_ACCEPT; |
| } |
| |
| msg = ntohs(ctlh->messageType); |
| DEBUGP("inbound control message %s\n", pptp_msg_name[msg]); |
| |
| switch (msg) { |
| case PPTP_START_SESSION_REPLY: |
| if (reqlen < sizeof(_pptpReq.srep)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* server confirms new control session */ |
| if (info->sstate < PPTP_SESSION_REQUESTED) { |
| DEBUGP("%s without START_SESS_REQUEST\n", |
| pptp_msg_name[msg]); |
| break; |
| } |
| if (pptpReq->srep.resultCode == PPTP_START_OK) |
| info->sstate = PPTP_SESSION_CONFIRMED; |
| else |
| info->sstate = PPTP_SESSION_ERROR; |
| break; |
| |
| case PPTP_STOP_SESSION_REPLY: |
| if (reqlen < sizeof(_pptpReq.strep)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* server confirms end of control session */ |
| if (info->sstate > PPTP_SESSION_STOPREQ) { |
| DEBUGP("%s without STOP_SESS_REQUEST\n", |
| pptp_msg_name[msg]); |
| break; |
| } |
| if (pptpReq->strep.resultCode == PPTP_STOP_OK) |
| info->sstate = PPTP_SESSION_NONE; |
| else |
| info->sstate = PPTP_SESSION_ERROR; |
| break; |
| |
| case PPTP_OUT_CALL_REPLY: |
| if (reqlen < sizeof(_pptpReq.ocack)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* server accepted call, we now expect GRE frames */ |
| if (info->sstate != PPTP_SESSION_CONFIRMED) { |
| DEBUGP("%s but no session\n", pptp_msg_name[msg]); |
| break; |
| } |
| if (info->cstate != PPTP_CALL_OUT_REQ && |
| info->cstate != PPTP_CALL_OUT_CONF) { |
| DEBUGP("%s without OUTCALL_REQ\n", pptp_msg_name[msg]); |
| break; |
| } |
| if (pptpReq->ocack.resultCode != PPTP_OUTCALL_CONNECT) { |
| info->cstate = PPTP_CALL_NONE; |
| break; |
| } |
| |
| cid = &pptpReq->ocack.callID; |
| pcid = &pptpReq->ocack.peersCallID; |
| |
| info->pac_call_id = ntohs(*cid); |
| |
| if (htons(info->pns_call_id) != *pcid) { |
| DEBUGP("%s for unknown callid %u\n", |
| pptp_msg_name[msg], ntohs(*pcid)); |
| break; |
| } |
| |
| DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg], |
| ntohs(*cid), ntohs(*pcid)); |
| |
| info->cstate = PPTP_CALL_OUT_CONF; |
| |
| seq = ntohl(tcph->seq) + sizeof(struct pptp_pkt_hdr) |
| + sizeof(struct PptpControlHeader) |
| + ((void *)pcid - (void *)pptpReq); |
| |
| if (exp_gre(ct, seq, *cid, *pcid) != 0) |
| printk("ip_conntrack_pptp: error during exp_gre\n"); |
| break; |
| |
| case PPTP_IN_CALL_REQUEST: |
| if (reqlen < sizeof(_pptpReq.icack)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* server tells us about incoming call request */ |
| if (info->sstate != PPTP_SESSION_CONFIRMED) { |
| DEBUGP("%s but no session\n", pptp_msg_name[msg]); |
| break; |
| } |
| pcid = &pptpReq->icack.peersCallID; |
| DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(*pcid)); |
| info->cstate = PPTP_CALL_IN_REQ; |
| info->pac_call_id = ntohs(*pcid); |
| break; |
| |
| case PPTP_IN_CALL_CONNECT: |
| if (reqlen < sizeof(_pptpReq.iccon)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* server tells us about incoming call established */ |
| if (info->sstate != PPTP_SESSION_CONFIRMED) { |
| DEBUGP("%s but no session\n", pptp_msg_name[msg]); |
| break; |
| } |
| if (info->cstate != PPTP_CALL_IN_REP |
| && info->cstate != PPTP_CALL_IN_CONF) { |
| DEBUGP("%s but never sent IN_CALL_REPLY\n", |
| pptp_msg_name[msg]); |
| break; |
| } |
| |
| pcid = &pptpReq->iccon.peersCallID; |
| cid = &info->pac_call_id; |
| |
| if (info->pns_call_id != ntohs(*pcid)) { |
| DEBUGP("%s for unknown CallID %u\n", |
| pptp_msg_name[msg], ntohs(*pcid)); |
| break; |
| } |
| |
| DEBUGP("%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 */ |
| seq = ntohl(tcph->seq) + sizeof(struct pptp_pkt_hdr) |
| + sizeof(struct PptpControlHeader) |
| + ((void *)pcid - (void *)pptpReq); |
| |
| if (exp_gre(ct, seq, *cid, *pcid) != 0) |
| printk("ip_conntrack_pptp: error during exp_gre\n"); |
| |
| break; |
| |
| case PPTP_CALL_DISCONNECT_NOTIFY: |
| if (reqlen < sizeof(_pptpReq.disc)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* server confirms disconnect */ |
| cid = &pptpReq->disc.callID; |
| DEBUGP("%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: |
| break; |
| |
| case PPTP_ECHO_REQUEST: |
| case PPTP_ECHO_REPLY: |
| /* I don't have to explain these ;) */ |
| break; |
| default: |
| DEBUGP("invalid %s (TY=%d)\n", (msg <= PPTP_MSG_MAX) |
| ? pptp_msg_name[msg]:pptp_msg_name[0], msg); |
| break; |
| } |
| |
| |
| if (ip_nat_pptp_hook_inbound) |
| return ip_nat_pptp_hook_inbound(pskb, ct, ctinfo, ctlh, |
| pptpReq); |
| |
| return NF_ACCEPT; |
| |
| } |
| |
| static inline int |
| pptp_outbound_pkt(struct sk_buff **pskb, |
| struct tcphdr *tcph, |
| unsigned int nexthdr_off, |
| unsigned int datalen, |
| struct ip_conntrack *ct, |
| enum ip_conntrack_info ctinfo) |
| { |
| struct PptpControlHeader _ctlh, *ctlh; |
| unsigned int reqlen; |
| union pptp_ctrl_union _pptpReq, *pptpReq; |
| struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
| u_int16_t msg; |
| __be16 *cid, *pcid; |
| |
| ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh); |
| if (!ctlh) |
| return NF_ACCEPT; |
| nexthdr_off += sizeof(_ctlh); |
| datalen -= sizeof(_ctlh); |
| |
| reqlen = datalen; |
| if (reqlen > sizeof(*pptpReq)) |
| reqlen = sizeof(*pptpReq); |
| pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq); |
| if (!pptpReq) |
| return NF_ACCEPT; |
| |
| msg = ntohs(ctlh->messageType); |
| DEBUGP("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) { |
| DEBUGP("%s but we already have one", |
| pptp_msg_name[msg]); |
| } |
| 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: |
| if (reqlen < sizeof(_pptpReq.ocreq)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| /* FIXME: break; */ |
| } |
| |
| /* client initiating connection to server */ |
| if (info->sstate != PPTP_SESSION_CONFIRMED) { |
| DEBUGP("%s but no session\n", |
| pptp_msg_name[msg]); |
| break; |
| } |
| info->cstate = PPTP_CALL_OUT_REQ; |
| /* track PNS call id */ |
| cid = &pptpReq->ocreq.callID; |
| DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(*cid)); |
| info->pns_call_id = ntohs(*cid); |
| break; |
| case PPTP_IN_CALL_REPLY: |
| if (reqlen < sizeof(_pptpReq.icack)) { |
| DEBUGP("%s: short packet\n", pptp_msg_name[msg]); |
| break; |
| } |
| |
| /* client answers incoming call */ |
| if (info->cstate != PPTP_CALL_IN_REQ |
| && info->cstate != PPTP_CALL_IN_REP) { |
| DEBUGP("%s without incall_req\n", |
| pptp_msg_name[msg]); |
| break; |
| } |
| if (pptpReq->icack.resultCode != PPTP_INCALL_ACCEPT) { |
| info->cstate = PPTP_CALL_NONE; |
| break; |
| } |
| pcid = &pptpReq->icack.peersCallID; |
| if (info->pac_call_id != ntohs(*pcid)) { |
| DEBUGP("%s for unknown call %u\n", |
| pptp_msg_name[msg], ntohs(*pcid)); |
| break; |
| } |
| DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(*pcid)); |
| /* part two of the three-way handshake */ |
| info->cstate = PPTP_CALL_IN_REP; |
| info->pns_call_id = ntohs(pptpReq->icack.callID); |
| break; |
| |
| case PPTP_CALL_CLEAR_REQUEST: |
| /* client requests hangup of call */ |
| if (info->sstate != PPTP_SESSION_CONFIRMED) { |
| DEBUGP("CLEAR_CALL but no session\n"); |
| break; |
| } |
| /* 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: |
| break; |
| case PPTP_ECHO_REQUEST: |
| case PPTP_ECHO_REPLY: |
| /* I don't have to explain these ;) */ |
| break; |
| default: |
| DEBUGP("invalid %s (TY=%d)\n", (msg <= PPTP_MSG_MAX)? |
| pptp_msg_name[msg]:pptp_msg_name[0], msg); |
| /* unknown: no need to create GRE masq table entry */ |
| break; |
| } |
| |
| if (ip_nat_pptp_hook_outbound) |
| return ip_nat_pptp_hook_outbound(pskb, ct, ctinfo, ctlh, |
| pptpReq); |
| |
| return NF_ACCEPT; |
| } |
| |
| |
| /* track caller id inside control connection, call expect_related */ |
| static int |
| conntrack_pptp_help(struct sk_buff **pskb, |
| struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) |
| |
| { |
| struct pptp_pkt_hdr _pptph, *pptph; |
| struct tcphdr _tcph, *tcph; |
| u_int32_t tcplen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4; |
| u_int32_t datalen; |
| int dir = CTINFO2DIR(ctinfo); |
| struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
| unsigned int nexthdr_off; |
| |
| int oldsstate, oldcstate; |
| int ret; |
| |
| /* don't do any tracking before tcp handshake complete */ |
| if (ctinfo != IP_CT_ESTABLISHED |
| && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) { |
| DEBUGP("ctinfo = %u, skipping\n", ctinfo); |
| return NF_ACCEPT; |
| } |
| |
| nexthdr_off = (*pskb)->nh.iph->ihl*4; |
| tcph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_tcph), &_tcph); |
| BUG_ON(!tcph); |
| nexthdr_off += tcph->doff * 4; |
| datalen = tcplen - tcph->doff * 4; |
| |
| if (tcph->fin || tcph->rst) { |
| DEBUGP("RST/FIN received, timeouting GRE\n"); |
| /* can't do this after real newnat */ |
| info->cstate = PPTP_CALL_NONE; |
| |
| /* untrack this call id, unexpect GRE packets */ |
| pptp_destroy_siblings(ct); |
| } |
| |
| pptph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_pptph), &_pptph); |
| if (!pptph) { |
| DEBUGP("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) { |
| DEBUGP("not a control packet\n"); |
| return NF_ACCEPT; |
| } |
| |
| oldsstate = info->sstate; |
| oldcstate = info->cstate; |
| |
| spin_lock_bh(&ip_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(pskb, tcph, nexthdr_off, datalen, ct, |
| ctinfo); |
| else |
| /* server -> client (PAC -> PNS) */ |
| ret = pptp_inbound_pkt(pskb, tcph, nexthdr_off, datalen, ct, |
| ctinfo); |
| DEBUGP("sstate: %d->%d, cstate: %d->%d\n", |
| oldsstate, info->sstate, oldcstate, info->cstate); |
| spin_unlock_bh(&ip_pptp_lock); |
| |
| return ret; |
| } |
| |
| /* control protocol helper */ |
| static struct ip_conntrack_helper pptp = { |
| .list = { NULL, NULL }, |
| .name = "pptp", |
| .me = THIS_MODULE, |
| .max_expected = 2, |
| .timeout = 5 * 60, |
| .tuple = { .src = { .ip = 0, |
| .u = { .tcp = { .port = |
| __constant_htons(PPTP_CONTROL_PORT) } } |
| }, |
| .dst = { .ip = 0, |
| .u = { .all = 0 }, |
| .protonum = IPPROTO_TCP |
| } |
| }, |
| .mask = { .src = { .ip = 0, |
| .u = { .tcp = { .port = __constant_htons(0xffff) } } |
| }, |
| .dst = { .ip = 0, |
| .u = { .all = 0 }, |
| .protonum = 0xff |
| } |
| }, |
| .help = conntrack_pptp_help |
| }; |
| |
| extern void ip_ct_proto_gre_fini(void); |
| extern int __init ip_ct_proto_gre_init(void); |
| |
| /* ip_conntrack_pptp initialization */ |
| static int __init ip_conntrack_helper_pptp_init(void) |
| { |
| int retcode; |
| |
| retcode = ip_ct_proto_gre_init(); |
| if (retcode < 0) |
| return retcode; |
| |
| DEBUGP(" registering helper\n"); |
| if ((retcode = ip_conntrack_helper_register(&pptp))) { |
| printk(KERN_ERR "Unable to register conntrack application " |
| "helper for pptp: %d\n", retcode); |
| ip_ct_proto_gre_fini(); |
| return retcode; |
| } |
| |
| printk("ip_conntrack_pptp version %s loaded\n", IP_CT_PPTP_VERSION); |
| return 0; |
| } |
| |
| static void __exit ip_conntrack_helper_pptp_fini(void) |
| { |
| ip_conntrack_helper_unregister(&pptp); |
| ip_ct_proto_gre_fini(); |
| printk("ip_conntrack_pptp version %s unloaded\n", IP_CT_PPTP_VERSION); |
| } |
| |
| module_init(ip_conntrack_helper_pptp_init); |
| module_exit(ip_conntrack_helper_pptp_fini); |
| |
| EXPORT_SYMBOL(ip_nat_pptp_hook_outbound); |
| EXPORT_SYMBOL(ip_nat_pptp_hook_inbound); |
| EXPORT_SYMBOL(ip_nat_pptp_hook_exp_gre); |
| EXPORT_SYMBOL(ip_nat_pptp_hook_expectfn); |