diff options
Diffstat (limited to 'net/ipv4/netfilter/ip_nat_helper_pptp.c')
-rw-r--r-- | net/ipv4/netfilter/ip_nat_helper_pptp.c | 188 |
1 files changed, 62 insertions, 126 deletions
diff --git a/net/ipv4/netfilter/ip_nat_helper_pptp.c b/net/ipv4/netfilter/ip_nat_helper_pptp.c index 1d14996..2ff5788 100644 --- a/net/ipv4/netfilter/ip_nat_helper_pptp.c +++ b/net/ipv4/netfilter/ip_nat_helper_pptp.c @@ -32,7 +32,7 @@ * 2005-06-10 - Version 3.0 * - kernel >= 2.6.11 version, * funded by Oxcoda NetBox Blue (http://www.netboxblue.com/) - * + * */ #include <linux/module.h> @@ -85,19 +85,17 @@ static void pptp_nat_expected(struct ip_conntrack *ct, DEBUGP("we are PNS->PAC\n"); /* therefore, build tuple for PAC->PNS */ t.src.ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip; - t.src.u.gre.key = htons(master->help.ct_pptp_info.pac_call_id); + t.src.u.gre.key = master->help.ct_pptp_info.pac_call_id; t.dst.ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; - t.dst.u.gre.key = htons(master->help.ct_pptp_info.pns_call_id); + t.dst.u.gre.key = master->help.ct_pptp_info.pns_call_id; t.dst.protonum = IPPROTO_GRE; } else { DEBUGP("we are PAC->PNS\n"); /* build tuple for PNS->PAC */ t.src.ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; - t.src.u.gre.key = - htons(master->nat.help.nat_pptp_info.pns_call_id); + t.src.u.gre.key = master->nat.help.nat_pptp_info.pns_call_id; t.dst.ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; - t.dst.u.gre.key = - htons(master->nat.help.nat_pptp_info.pac_call_id); + t.dst.u.gre.key = master->nat.help.nat_pptp_info.pac_call_id; t.dst.protonum = IPPROTO_GRE; } @@ -149,51 +147,52 @@ pptp_outbound_pkt(struct sk_buff **pskb, { struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info; struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info; - u_int16_t msg, new_callid; + u_int16_t msg; + __be16 new_callid; unsigned int cid_off; - new_callid = htons(ct_pptp_info->pns_call_id); - + new_callid = ct_pptp_info->pns_call_id; + switch (msg = ntohs(ctlh->messageType)) { - case PPTP_OUT_CALL_REQUEST: - cid_off = offsetof(union pptp_ctrl_union, ocreq.callID); - /* FIXME: ideally we would want to reserve a call ID - * here. current netfilter NAT core is not able to do - * this :( For now we use TCP source port. This breaks - * multiple calls within one control session */ - - /* save original call ID in nat_info */ - nat_pptp_info->pns_call_id = ct_pptp_info->pns_call_id; - - /* don't use tcph->source since we are at a DSTmanip - * hook (e.g. PREROUTING) and pkt is not mangled yet */ - new_callid = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.tcp.port; - - /* save new call ID in ct info */ - ct_pptp_info->pns_call_id = ntohs(new_callid); - break; - case PPTP_IN_CALL_REPLY: - cid_off = offsetof(union pptp_ctrl_union, icreq.callID); - break; - case PPTP_CALL_CLEAR_REQUEST: - cid_off = offsetof(union pptp_ctrl_union, clrreq.callID); - break; - default: - DEBUGP("unknown outbound packet 0x%04x:%s\n", msg, - (msg <= PPTP_MSG_MAX)? - pptp_msg_name[msg]:pptp_msg_name[0]); - /* fall through */ - - case PPTP_SET_LINK_INFO: - /* only need to NAT in case PAC is behind NAT box */ - case PPTP_START_SESSION_REQUEST: - case PPTP_START_SESSION_REPLY: - case PPTP_STOP_SESSION_REQUEST: - case PPTP_STOP_SESSION_REPLY: - case PPTP_ECHO_REQUEST: - case PPTP_ECHO_REPLY: - /* no need to alter packet */ - return NF_ACCEPT; + case PPTP_OUT_CALL_REQUEST: + cid_off = offsetof(union pptp_ctrl_union, ocreq.callID); + /* FIXME: ideally we would want to reserve a call ID + * here. current netfilter NAT core is not able to do + * this :( For now we use TCP source port. This breaks + * multiple calls within one control session */ + + /* save original call ID in nat_info */ + nat_pptp_info->pns_call_id = ct_pptp_info->pns_call_id; + + /* don't use tcph->source since we are at a DSTmanip + * hook (e.g. PREROUTING) and pkt is not mangled yet */ + new_callid = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.tcp.port; + + /* save new call ID in ct info */ + ct_pptp_info->pns_call_id = new_callid; + break; + case PPTP_IN_CALL_REPLY: + cid_off = offsetof(union pptp_ctrl_union, icack.callID); + break; + case PPTP_CALL_CLEAR_REQUEST: + cid_off = offsetof(union pptp_ctrl_union, clrreq.callID); + break; + default: + DEBUGP("unknown outbound packet 0x%04x:%s\n", msg, + (msg <= PPTP_MSG_MAX)? + pptp_msg_name[msg]:pptp_msg_name[0]); + /* fall through */ + + case PPTP_SET_LINK_INFO: + /* only need to NAT in case PAC is behind NAT box */ + case PPTP_START_SESSION_REQUEST: + case PPTP_START_SESSION_REPLY: + case PPTP_STOP_SESSION_REQUEST: + case PPTP_STOP_SESSION_REPLY: + case PPTP_ECHO_REQUEST: + case PPTP_ECHO_REPLY: + /* no need to alter packet */ + return NF_ACCEPT; } /* only OUT_CALL_REQUEST, IN_CALL_REPLY, CALL_CLEAR_REQUEST pass @@ -212,80 +211,28 @@ pptp_outbound_pkt(struct sk_buff **pskb, return NF_ACCEPT; } -static int +static void pptp_exp_gre(struct ip_conntrack_expect *expect_orig, struct ip_conntrack_expect *expect_reply) { - struct ip_ct_pptp_master *ct_pptp_info = - &expect_orig->master->help.ct_pptp_info; - struct ip_nat_pptp *nat_pptp_info = - &expect_orig->master->nat.help.nat_pptp_info; - struct ip_conntrack *ct = expect_orig->master; - - struct ip_conntrack_tuple inv_t; - struct ip_conntrack_tuple *orig_t, *reply_t; + struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info; + struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info; /* save original PAC call ID in nat_info */ nat_pptp_info->pac_call_id = ct_pptp_info->pac_call_id; - /* alter expectation */ - orig_t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; - reply_t = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; - /* alter expectation for PNS->PAC direction */ - invert_tuplepr(&inv_t, &expect_orig->tuple); - expect_orig->saved_proto.gre.key = htons(ct_pptp_info->pns_call_id); - expect_orig->tuple.src.u.gre.key = htons(nat_pptp_info->pns_call_id); - expect_orig->tuple.dst.u.gre.key = htons(ct_pptp_info->pac_call_id); + expect_orig->saved_proto.gre.key = ct_pptp_info->pns_call_id; + expect_orig->tuple.src.u.gre.key = nat_pptp_info->pns_call_id; + expect_orig->tuple.dst.u.gre.key = ct_pptp_info->pac_call_id; expect_orig->dir = IP_CT_DIR_ORIGINAL; - inv_t.src.ip = reply_t->src.ip; - inv_t.dst.ip = reply_t->dst.ip; - inv_t.src.u.gre.key = htons(nat_pptp_info->pac_call_id); - inv_t.dst.u.gre.key = htons(ct_pptp_info->pns_call_id); - - if (!ip_conntrack_expect_related(expect_orig)) { - DEBUGP("successfully registered expect\n"); - } else { - DEBUGP("can't expect_related(expect_orig)\n"); - return 1; - } /* alter expectation for PAC->PNS direction */ - invert_tuplepr(&inv_t, &expect_reply->tuple); - expect_reply->saved_proto.gre.key = htons(nat_pptp_info->pns_call_id); - expect_reply->tuple.src.u.gre.key = htons(nat_pptp_info->pac_call_id); - expect_reply->tuple.dst.u.gre.key = htons(ct_pptp_info->pns_call_id); + expect_reply->saved_proto.gre.key = nat_pptp_info->pns_call_id; + expect_reply->tuple.src.u.gre.key = nat_pptp_info->pac_call_id; + expect_reply->tuple.dst.u.gre.key = ct_pptp_info->pns_call_id; expect_reply->dir = IP_CT_DIR_REPLY; - inv_t.src.ip = orig_t->src.ip; - inv_t.dst.ip = orig_t->dst.ip; - inv_t.src.u.gre.key = htons(nat_pptp_info->pns_call_id); - inv_t.dst.u.gre.key = htons(ct_pptp_info->pac_call_id); - - if (!ip_conntrack_expect_related(expect_reply)) { - DEBUGP("successfully registered expect\n"); - } else { - DEBUGP("can't expect_related(expect_reply)\n"); - ip_conntrack_unexpect_related(expect_orig); - return 1; - } - - if (ip_ct_gre_keymap_add(ct, &expect_reply->tuple, 0) < 0) { - DEBUGP("can't register original keymap\n"); - ip_conntrack_unexpect_related(expect_orig); - ip_conntrack_unexpect_related(expect_reply); - return 1; - } - - if (ip_ct_gre_keymap_add(ct, &inv_t, 1) < 0) { - DEBUGP("can't register reply keymap\n"); - ip_conntrack_unexpect_related(expect_orig); - ip_conntrack_unexpect_related(expect_reply); - ip_ct_gre_keymap_destroy(ct); - return 1; - } - - return 0; } /* inbound packets == from PAC to PNS */ @@ -297,15 +244,15 @@ pptp_inbound_pkt(struct sk_buff **pskb, union pptp_ctrl_union *pptpReq) { struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info; - u_int16_t msg, new_cid = 0, new_pcid; - unsigned int pcid_off, cid_off = 0; + u_int16_t msg; + __be16 new_pcid; + unsigned int pcid_off; - new_pcid = htons(nat_pptp_info->pns_call_id); + new_pcid = nat_pptp_info->pns_call_id; switch (msg = ntohs(ctlh->messageType)) { case PPTP_OUT_CALL_REPLY: pcid_off = offsetof(union pptp_ctrl_union, ocack.peersCallID); - cid_off = offsetof(union pptp_ctrl_union, ocack.callID); break; case PPTP_IN_CALL_CONNECT: pcid_off = offsetof(union pptp_ctrl_union, iccon.peersCallID); @@ -324,7 +271,7 @@ pptp_inbound_pkt(struct sk_buff **pskb, break; default: - DEBUGP("unknown inbound packet %s\n", (msg <= PPTP_MSG_MAX)? + DEBUGP("unknown inbound packet %s\n", (msg <= PPTP_MSG_MAX)? pptp_msg_name[msg]:pptp_msg_name[0]); /* fall through */ @@ -351,17 +298,6 @@ pptp_inbound_pkt(struct sk_buff **pskb, sizeof(new_pcid), (char *)&new_pcid, sizeof(new_pcid)) == 0) return NF_DROP; - - if (new_cid) { - DEBUGP("altering call id from 0x%04x to 0x%04x\n", - ntohs(REQ_CID(pptpReq, cid_off)), ntohs(new_cid)); - if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, - cid_off + sizeof(struct pptp_pkt_hdr) + - sizeof(struct PptpControlHeader), - sizeof(new_cid), (char *)&new_cid, - sizeof(new_cid)) == 0) - return NF_DROP; - } return NF_ACCEPT; } |