static int map_addr(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int matchoff, unsigned int matchlen,
union nf_inet_addr *addr, __be16 port)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
unsigned int buflen;
union nf_inet_addr newaddr;
__be16 newport;
if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, addr) &&
ct->tuplehash[dir].tuple.src.u.udp.port == port) {
newaddr = ct->tuplehash[!dir].tuple.dst.u3;
newport = ct->tuplehash[!dir].tuple.dst.u.udp.port;
} else if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, addr) &&
ct->tuplehash[dir].tuple.dst.u.udp.port == port) {
newaddr = ct->tuplehash[!dir].tuple.src.u3;
newport = ct_sip_info->forced_dport ? :
ct->tuplehash[!dir].tuple.src.u.udp.port;
} else
static void
pptp_exp_gre(struct nf_conntrack_expect *expect_orig,
struct nf_conntrack_expect *expect_reply)
{
const struct nf_conn *ct = expect_orig->master;
struct nf_ct_pptp_master *ct_pptp_info;
struct nf_nat_pptp *nat_pptp_info;
ct_pptp_info = nfct_help_data(ct);
nat_pptp_info = &nfct_nat(ct)->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 for PNS->PAC direction */
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;
/* alter expectation for PAC->PNS direction */
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;
}
static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int protoff, unsigned char **data, int dataoff,
TransportAddress *taddr, __be16 port,
struct nf_conntrack_expect *exp)
{
struct nf_ct_h323_master *info = nfct_help_data(ct);
int dir = CTINFO2DIR(ctinfo);
u_int16_t nated_port = ntohs(port);
/* Set expectations for NAT */
exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
exp->expectfn = nf_nat_follow_master;
exp->dir = !dir;
/* Check existing expects */
if (info->sig_port[dir] == port)
nated_port = ntohs(info->sig_port[!dir]);
/* Try to get same port: if not, try to change it. */
for (; nated_port != 0; nated_port++) {
int ret;
exp->tuple.dst.u.tcp.port = htons(nated_port);
ret = nf_ct_expect_related(exp);
if (ret == 0)
break;
else if (ret != -EBUSY) {
nated_port = 0;
break;
}
}
if (nated_port == 0) { /* No port available */
net_notice_ratelimited("nf_nat_q931: out of TCP ports\n");
return 0;
}
/* Modify signal */
if (set_h225_addr(skb, protoff, data, dataoff, taddr,
&ct->tuplehash[!dir].tuple.dst.u3,
htons(nated_port)) == 0) {
/* Save ports */
info->sig_port[dir] = port;
info->sig_port[!dir] = htons(nated_port);
} else {
nf_ct_unexpect_related(exp);
return -1;
}
pr_debug("nf_nat_q931: expect H.245 %pI4:%hu->%pI4:%hu\n",
&exp->tuple.src.u3.ip,
ntohs(exp->tuple.src.u.tcp.port),
&exp->tuple.dst.u3.ip,
ntohs(exp->tuple.dst.u.tcp.port));
return 0;
}
static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int protoff, unsigned char **data,
TransportAddress *taddr, int count)
{
const struct nf_ct_h323_master *info = nfct_help_data(ct);
int dir = CTINFO2DIR(ctinfo);
int i;
__be16 port;
union nf_inet_addr addr;
for (i = 0; i < count; i++) {
if (get_h225_addr(ct, *data, &taddr[i], &addr, &port)) {
if (addr.ip == ct->tuplehash[dir].tuple.src.u3.ip &&
port == info->sig_port[dir]) {
/* GW->GK */
/* Fix for Gnomemeeting */
if (i > 0 &&
get_h225_addr(ct, *data, &taddr[0],
&addr, &port) &&
(ntohl(addr.ip) & 0xff000000) == 0x7f000000)
i = 0;
pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
&addr.ip, port,
&ct->tuplehash[!dir].tuple.dst.u3.ip,
info->sig_port[!dir]);
return set_h225_addr(skb, protoff, data, 0,
&taddr[i],
&ct->tuplehash[!dir].
tuple.dst.u3,
info->sig_port[!dir]);
} else if (addr.ip == ct->tuplehash[dir].tuple.dst.u3.ip &&
port == info->sig_port[dir]) {
/* GK->GW */
pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
&addr.ip, port,
&ct->tuplehash[!dir].tuple.src.u3.ip,
info->sig_port[!dir]);
return set_h225_addr(skb, protoff, data, 0,
&taddr[i],
&ct->tuplehash[!dir].
tuple.src.u3,
info->sig_port[!dir]);
}
}
}
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");
}
static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int protoff, unsigned char **data, int dataoff,
H245_TransportAddress *taddr,
__be16 port, __be16 rtp_port,
struct nf_conntrack_expect *rtp_exp,
struct nf_conntrack_expect *rtcp_exp)
{
struct nf_ct_h323_master *info = nfct_help_data(ct);
int dir = CTINFO2DIR(ctinfo);
int i;
u_int16_t nated_port;
/* Set expectations for NAT */
rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port;
rtp_exp->expectfn = nf_nat_follow_master;
rtp_exp->dir = !dir;
rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port;
rtcp_exp->expectfn = nf_nat_follow_master;
rtcp_exp->dir = !dir;
/* Lookup existing expects */
for (i = 0; i < H323_RTP_CHANNEL_MAX; i++) {
if (info->rtp_port[i][dir] == rtp_port) {
/* Expected */
/* Use allocated ports first. This will refresh
* the expects */
rtp_exp->tuple.dst.u.udp.port = info->rtp_port[i][dir];
rtcp_exp->tuple.dst.u.udp.port =
htons(ntohs(info->rtp_port[i][dir]) + 1);
break;
} else if (info->rtp_port[i][dir] == 0) {
/* Not expected */
break;
}
}
/* Run out of expectations */
if (i >= H323_RTP_CHANNEL_MAX) {
net_notice_ratelimited("nf_nat_h323: out of expectations\n");
return 0;
}
/* Try to get a pair of ports. */
for (nated_port = ntohs(rtp_exp->tuple.dst.u.udp.port);
nated_port != 0; nated_port += 2) {
int ret;
rtp_exp->tuple.dst.u.udp.port = htons(nated_port);
ret = nf_ct_expect_related(rtp_exp);
if (ret == 0) {
rtcp_exp->tuple.dst.u.udp.port =
htons(nated_port + 1);
ret = nf_ct_expect_related(rtcp_exp);
if (ret == 0)
break;
else if (ret != -EBUSY) {
nf_ct_unexpect_related(rtp_exp);
nated_port = 0;
break;
}
} else if (ret != -EBUSY) {
nated_port = 0;
break;
}
}
if (nated_port == 0) { /* No port available */
net_notice_ratelimited("nf_nat_h323: out of RTP ports\n");
return 0;
}
/* Modify signal */
if (set_h245_addr(skb, protoff, data, dataoff, taddr,
&ct->tuplehash[!dir].tuple.dst.u3,
htons((port & htons(1)) ? nated_port + 1 :
nated_port)) == 0) {
/* Save ports */
info->rtp_port[i][dir] = rtp_port;
info->rtp_port[i][!dir] = htons(nated_port);
} else {
nf_ct_unexpect_related(rtp_exp);
nf_ct_unexpect_related(rtcp_exp);
return -1;
}
/* Success */
pr_debug("nf_nat_h323: expect RTP %pI4:%hu->%pI4:%hu\n",
&rtp_exp->tuple.src.u3.ip,
ntohs(rtp_exp->tuple.src.u.udp.port),
&rtp_exp->tuple.dst.u3.ip,
ntohs(rtp_exp->tuple.dst.u.udp.port));
pr_debug("nf_nat_h323: expect RTCP %pI4:%hu->%pI4:%hu\n",
&rtcp_exp->tuple.src.u3.ip,
ntohs(rtcp_exp->tuple.src.u.udp.port),
&rtcp_exp->tuple.dst.u3.ip,
ntohs(rtcp_exp->tuple.dst.u.udp.port));
return 0;
}
static void pptp_nat_expected(struct nf_conn *ct,
struct nf_conntrack_expect *exp)
{
struct net *net = nf_ct_net(ct);
const struct nf_conn *master = ct->master;
struct nf_conntrack_expect *other_exp;
struct nf_conntrack_tuple t = {};
const struct nf_ct_pptp_master *ct_pptp_info;
const struct nf_nat_pptp *nat_pptp_info;
struct nf_nat_range range;
ct_pptp_info = nfct_help_data(master);
nat_pptp_info = &nfct_nat(master)->help.nat_pptp_info;
/* And here goes the grand finale of corrosion... */
if (exp->dir == IP_CT_DIR_ORIGINAL) {
pr_debug("we are PNS->PAC\n");
/* therefore, build tuple for PAC->PNS */
t.src.l3num = AF_INET;
t.src.u3.ip = master->tuplehash[!exp->dir].tuple.src.u3.ip;
t.src.u.gre.key = ct_pptp_info->pac_call_id;
t.dst.u3.ip = master->tuplehash[!exp->dir].tuple.dst.u3.ip;
t.dst.u.gre.key = ct_pptp_info->pns_call_id;
t.dst.protonum = IPPROTO_GRE;
} else {
pr_debug("we are PAC->PNS\n");
/* build tuple for PNS->PAC */
t.src.l3num = AF_INET;
t.src.u3.ip = master->tuplehash[!exp->dir].tuple.src.u3.ip;
t.src.u.gre.key = nat_pptp_info->pns_call_id;
t.dst.u3.ip = master->tuplehash[!exp->dir].tuple.dst.u3.ip;
t.dst.u.gre.key = nat_pptp_info->pac_call_id;
t.dst.protonum = IPPROTO_GRE;
}
pr_debug("trying to unexpect other dir: ");
nf_ct_dump_tuple_ip(&t);
other_exp = nf_ct_expect_find_get(net, nf_ct_zone(ct), &t);
if (other_exp) {
nf_ct_unexpect_related(other_exp);
nf_ct_expect_put(other_exp);
pr_debug("success\n");
} else {
pr_debug("not found!\n");
}
/* This must be a fresh one. */
BUG_ON(ct->status & IPS_NAT_DONE_MASK);
/* Change src to where master sends to */
range.flags = NF_NAT_RANGE_MAP_IPS;
range.min_addr = range.max_addr
= ct->master->tuplehash[!exp->dir].tuple.dst.u3;
if (exp->dir == IP_CT_DIR_ORIGINAL) {
range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
range.min_proto = range.max_proto = exp->saved_proto;
}
nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
/* For DST manip, map port here to where it's expected. */
range.flags = NF_NAT_RANGE_MAP_IPS;
range.min_addr = range.max_addr
= ct->master->tuplehash[!exp->dir].tuple.src.u3;
if (exp->dir == IP_CT_DIR_REPLY) {
range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
range.min_proto = range.max_proto = exp->saved_proto;
}
nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
}
/* outbound packets == from PNS to PAC */
static int
pptp_outbound_pkt(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int protoff,
struct PptpControlHeader *ctlh,
union pptp_ctrl_union *pptpReq)
{
struct nf_ct_pptp_master *ct_pptp_info;
struct nf_nat_pptp *nat_pptp_info;
u_int16_t msg;
__be16 new_callid;
unsigned int cid_off;
ct_pptp_info = nfct_help_data(ct);
nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
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 = 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:
pr_debug("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
* down to here */
pr_debug("altering call id from 0x%04x to 0x%04x\n",
ntohs(REQ_CID(pptpReq, cid_off)), ntohs(new_callid));
/* mangle packet */
if (nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff,
cid_off + sizeof(struct pptp_pkt_hdr) +
sizeof(struct PptpControlHeader),
sizeof(new_callid), (char *)&new_callid,
sizeof(new_callid)) == 0)
return NF_DROP;
return NF_ACCEPT;
}
/* 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 protoff;
unsigned int datalen, reqlen, nexthdr_off;
int oldsstate, oldcstate;
int ret;
u_int16_t msg;
/* 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 inline 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",
msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0],
msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
ntohs(info->pns_call_id), ntohs(info->pac_call_id));
return NF_ACCEPT;
}
static inline 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",
msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0],
msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
ntohs(info->pns_call_id), ntohs(info->pac_call_id));
return NF_ACCEPT;
}
static int help(struct sk_buff *skb,
unsigned int protoff,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
unsigned int dataoff, datalen;
const struct tcphdr *th;
struct tcphdr _tcph;
void *sb_ptr;
int ret = NF_ACCEPT;
int dir = CTINFO2DIR(ctinfo);
struct nf_ct_sane_master *ct_sane_info = nfct_help_data(ct);
struct nf_conntrack_expect *exp;
struct nf_conntrack_tuple *tuple;
struct sane_request *req;
struct sane_reply_net_start *reply;
/* Until there's been traffic both ways, don't look in packets. */
if (ctinfo != IP_CT_ESTABLISHED &&
ctinfo != IP_CT_ESTABLISHED_REPLY)
return NF_ACCEPT;
/* Not a full tcp header? */
th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
if (th == NULL)
return NF_ACCEPT;
/* No data? */
dataoff = protoff + th->doff * 4;
if (dataoff >= skb->len)
return NF_ACCEPT;
datalen = skb->len - dataoff;
spin_lock_bh(&nf_sane_lock);
sb_ptr = skb_header_pointer(skb, dataoff, datalen, sane_buffer);
BUG_ON(sb_ptr == NULL);
if (dir == IP_CT_DIR_ORIGINAL) {
if (datalen != sizeof(struct sane_request))
goto out;
req = sb_ptr;
if (req->RPC_code != htonl(SANE_NET_START)) {
/* Not an interesting command */
ct_sane_info->state = SANE_STATE_NORMAL;
goto out;
}
/* We're interested in the next reply */
ct_sane_info->state = SANE_STATE_START_REQUESTED;
goto out;
}
/* Is it a reply to an uninteresting command? */
if (ct_sane_info->state != SANE_STATE_START_REQUESTED)
goto out;
/* It's a reply to SANE_NET_START. */
ct_sane_info->state = SANE_STATE_NORMAL;
if (datalen < sizeof(struct sane_reply_net_start)) {
pr_debug("NET_START reply too short\n");
goto out;
}
reply = sb_ptr;
if (reply->status != htonl(SANE_STATUS_SUCCESS)) {
/* saned refused the command */
pr_debug("unsuccessful SANE_STATUS = %u\n",
ntohl(reply->status));
goto out;
}
/* Invalid saned reply? Ignore it. */
if (reply->zero != 0)
goto out;
exp = nf_ct_expect_alloc(ct);
if (exp == NULL) {
nf_ct_helper_log(skb, ct, "cannot alloc expectation");
ret = NF_DROP;
goto out;
}
tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
&tuple->src.u3, &tuple->dst.u3,
IPPROTO_TCP, NULL, &reply->port);
pr_debug("expect: ");
nf_ct_dump_tuple(&exp->tuple);
/* Can't expect this? Best to drop packet now. */
if (nf_ct_expect_related(exp) != 0) {
nf_ct_helper_log(skb, ct, "cannot add expectation");
ret = NF_DROP;
}
nf_ct_expect_put(exp);
out:
spin_unlock_bh(&nf_sane_lock);
return ret;
}