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-rw-r--r--lib/libalias/alias.c51
-rw-r--r--lib/libalias/alias_db.c167
-rw-r--r--lib/libalias/alias_local.h18
-rw-r--r--lib/libalias/alias_pptp.c180
4 files changed, 265 insertions, 151 deletions
diff --git a/lib/libalias/alias.c b/lib/libalias/alias.c
index 4dc1800..a2ef4bf 100644
--- a/lib/libalias/alias.c
+++ b/lib/libalias/alias.c
@@ -185,7 +185,6 @@ TcpMonitorOut(struct ip *pip, struct alias_link *link)
ProtoAliasIn(), ProtoAliasOut()
UdpAliasIn(), UdpAliasOut()
TcpAliasIn(), TcpAliasOut()
- GreAliasIn()
These routines handle protocol specific details of packet aliasing.
One may observe a certain amount of repetitive arithmetic in these
@@ -237,8 +236,6 @@ static int UdpAliasIn (struct ip *);
static int TcpAliasOut(struct ip *, int);
static int TcpAliasIn (struct ip *);
-static int GreAliasIn(struct ip *);
-
static int
IcmpAliasIn1(struct ip *pip)
@@ -707,40 +704,6 @@ ProtoAliasOut(struct ip *pip)
static int
-GreAliasIn(struct ip *pip)
-{
- u_short call_id;
- struct alias_link *link;
-
-/* Return if proxy-only mode is enabled. */
- if (packetAliasMode & PKT_ALIAS_PROXY_ONLY)
- return (PKT_ALIAS_OK);
-
- if (PptpGetCallID(pip, &call_id)) {
- if ((link = FindPptpIn(pip->ip_src, pip->ip_dst, call_id)) != NULL) {
- struct in_addr alias_address;
- struct in_addr original_address;
-
- alias_address = GetAliasAddress(link);
- original_address = GetOriginalAddress(link);
- PptpSetCallID(pip, GetOriginalPort(link));
-
- /* Restore original IP address. */
- DifferentialChecksum(&pip->ip_sum,
- (u_short *)&original_address,
- (u_short *)&pip->ip_dst,
- 2);
- pip->ip_dst = original_address;
-
- return (PKT_ALIAS_OK);
- } else
- return (PKT_ALIAS_IGNORED);
- } else
- return ProtoAliasIn(pip);
-}
-
-
-static int
UdpAliasIn(struct ip *pip)
{
struct udphdr *ud;
@@ -1318,8 +1281,12 @@ PacketAliasIn(char *ptr, int maxpacketsize)
iresult = TcpAliasIn(pip);
break;
case IPPROTO_GRE:
- iresult = GreAliasIn(pip);
- break;
+ if (packetAliasMode & PKT_ALIAS_PROXY_ONLY ||
+ AliasHandlePptpGreIn(pip) == 0)
+ iresult = PKT_ALIAS_OK;
+ else
+ iresult = ProtoAliasIn(pip);
+ break;
default:
iresult = ProtoAliasIn(pip);
break;
@@ -1426,6 +1393,12 @@ PacketAliasOut(char *ptr, /* valid IP packet */
case IPPROTO_TCP:
iresult = TcpAliasOut(pip, maxpacketsize);
break;
+ case IPPROTO_GRE:
+ if (AliasHandlePptpGreOut(pip) == 0)
+ iresult = PKT_ALIAS_OK;
+ else
+ iresult = ProtoAliasOut(pip);
+ break;
default:
iresult = ProtoAliasOut(pip);
break;
diff --git a/lib/libalias/alias_db.c b/lib/libalias/alias_db.c
index dcbf117..7b04548 100644
--- a/lib/libalias/alias_db.c
+++ b/lib/libalias/alias_db.c
@@ -158,7 +158,6 @@
/* Timeouts (in seconds) for different link types */
#define ICMP_EXPIRE_TIME 60
#define UDP_EXPIRE_TIME 60
-#define PPTP_EXPIRE_TIME 60
#define PROTO_EXPIRE_TIME 60
#define FRAGMENT_ID_EXPIRE_TIME 10
#define FRAGMENT_PTR_EXPIRE_TIME 30
@@ -422,7 +421,8 @@ StartPointIn(struct in_addr alias_addr,
u_int n;
n = alias_addr.s_addr;
- n += alias_port;
+ if (link_type != LINK_PPTP)
+ n += alias_port;
n += link_type;
return(n % LINK_TABLE_IN_SIZE);
}
@@ -436,8 +436,10 @@ StartPointOut(struct in_addr src_addr, struct in_addr dst_addr,
n = src_addr.s_addr;
n += dst_addr.s_addr;
- n += src_port;
- n += dst_port;
+ if (link_type != LINK_PPTP) {
+ n += src_port;
+ n += dst_port;
+ }
n += link_type;
return(n % LINK_TABLE_OUT_SIZE);
@@ -1004,7 +1006,7 @@ AddLink(struct in_addr src_addr,
link->expire_time = TCP_EXPIRE_INITIAL;
break;
case LINK_PPTP:
- link->expire_time = PPTP_EXPIRE_TIME;
+ link->flags |= LINK_PERMANENT; /* no timeout. */
break;
case LINK_FRAGMENT_ID:
link->expire_time = FRAGMENT_ID_EXPIRE_TIME;
@@ -1389,7 +1391,8 @@ FindLinkIn(struct in_addr dst_addr,
AddFragmentPtrLink(), FindFragmentPtr()
FindProtoIn(), FindProtoOut()
FindUdpTcpIn(), FindUdpTcpOut()
- FindPptpIn(), FindPptpOut()
+ AddPptp(), FindPptpOutByCallId(), FindPptpInByCallId(),
+ FindPptpOutByPeerCallId(), FindPptpInByPeerCallId()
FindOriginalAddress(), FindAliasAddress()
(prototypes in alias_local.h)
@@ -1630,56 +1633,6 @@ FindUdpTcpOut(struct in_addr src_addr,
struct alias_link *
-FindPptpIn(struct in_addr dst_addr,
- struct in_addr alias_addr,
- u_short call_id)
-{
- struct alias_link *link;
-
- link = FindLinkIn(dst_addr, alias_addr,
- NO_DEST_PORT, call_id,
- LINK_PPTP, 1);
-
- if (link == NULL && !(packetAliasMode & PKT_ALIAS_DENY_INCOMING))
- {
- struct in_addr target_addr;
-
- target_addr = FindOriginalAddress(alias_addr);
- link = AddLink(target_addr, dst_addr, alias_addr,
- call_id, NO_DEST_PORT, call_id,
- LINK_PPTP);
- }
-
- return(link);
-}
-
-
-struct alias_link *
-FindPptpOut(struct in_addr src_addr,
- struct in_addr dst_addr,
- u_short call_id)
-{
- struct alias_link *link;
-
- link = FindLinkOut(src_addr, dst_addr,
- call_id, NO_DEST_PORT,
- LINK_PPTP, 1);
-
- if (link == NULL)
- {
- struct in_addr alias_addr;
-
- alias_addr = FindAliasAddress(src_addr);
- link = AddLink(src_addr, dst_addr, alias_addr,
- call_id, NO_DEST_PORT, GET_ALIAS_PORT,
- LINK_PPTP);
- }
-
- return(link);
-}
-
-
-struct alias_link *
QueryUdpTcpIn(struct in_addr dst_addr,
struct in_addr alias_addr,
u_short dst_port,
@@ -1740,6 +1693,97 @@ QueryUdpTcpOut(struct in_addr src_addr,
return(link);
}
+struct alias_link *
+AddPptp(struct in_addr src_addr,
+ struct in_addr dst_addr,
+ struct in_addr alias_addr,
+ u_int16_t src_call_id)
+{
+ struct alias_link *link;
+
+ link = AddLink(src_addr, dst_addr, alias_addr,
+ src_call_id, 0, GET_ALIAS_PORT,
+ LINK_PPTP);
+
+ return (link);
+}
+
+
+struct alias_link *
+FindPptpOutByCallId(struct in_addr src_addr,
+ struct in_addr dst_addr,
+ u_int16_t src_call_id)
+{
+ u_int i;
+ struct alias_link *link;
+
+ i = StartPointOut(src_addr, dst_addr, 0, 0, LINK_PPTP);
+ LIST_FOREACH(link, &linkTableOut[i], list_out)
+ if (link->link_type == LINK_PPTP &&
+ link->src_addr.s_addr == src_addr.s_addr &&
+ link->dst_addr.s_addr == dst_addr.s_addr &&
+ link->src_port == src_call_id)
+ break;
+
+ return (link);
+}
+
+
+struct alias_link *
+FindPptpOutByPeerCallId(struct in_addr src_addr,
+ struct in_addr dst_addr,
+ u_int16_t dst_call_id)
+{
+ u_int i;
+ struct alias_link *link;
+
+ i = StartPointOut(src_addr, dst_addr, 0, 0, LINK_PPTP);
+ LIST_FOREACH(link, &linkTableOut[i], list_out)
+ if (link->link_type == LINK_PPTP &&
+ link->src_addr.s_addr == src_addr.s_addr &&
+ link->dst_addr.s_addr == dst_addr.s_addr &&
+ link->dst_port == dst_call_id)
+ break;
+
+ return (link);
+}
+
+
+struct alias_link *
+FindPptpInByCallId(struct in_addr dst_addr,
+ struct in_addr alias_addr,
+ u_int16_t dst_call_id)
+{
+ u_int i;
+ struct alias_link *link;
+
+ i = StartPointIn(alias_addr, 0, LINK_PPTP);
+ LIST_FOREACH(link, &linkTableIn[i], list_in)
+ if (link->link_type == LINK_PPTP &&
+ link->dst_addr.s_addr == dst_addr.s_addr &&
+ link->alias_addr.s_addr == alias_addr.s_addr &&
+ link->dst_port == dst_call_id)
+ break;
+
+ return (link);
+}
+
+
+struct alias_link *
+FindPptpInByPeerCallId(struct in_addr dst_addr,
+ struct in_addr alias_addr,
+ u_int16_t alias_call_id)
+{
+ struct alias_link *link;
+
+ link = FindLinkIn(dst_addr, alias_addr,
+ 0/* any */, alias_call_id,
+ LINK_PPTP, 0);
+
+
+ return (link);
+}
+
struct alias_link *
FindRtspOut(struct in_addr src_addr,
@@ -1845,6 +1889,7 @@ FindAliasAddress(struct in_addr original_addr)
SetAckModified(), GetAckModified()
GetDeltaAckIn(), GetDeltaSeqOut(), AddSeq()
SetLastLineCrlfTermed(), GetLastLineCrlfTermed()
+ SetDestCallId()
*/
@@ -2227,6 +2272,16 @@ GetLastLineCrlfTermed(struct alias_link *link)
return (link->flags & LINK_LAST_LINE_CRLF_TERMED);
}
+void
+SetDestCallId(struct alias_link *link, u_int16_t cid)
+{
+
+ deleteAllLinks = 1;
+ link = ReLink(link, link->src_addr, link->dst_addr, link->alias_addr,
+ link->src_port, cid, link->alias_port, link->link_type);
+ deleteAllLinks = 0;
+}
+
/* Miscellaneous Functions
diff --git a/lib/libalias/alias_local.h b/lib/libalias/alias_local.h
index f916d21..bd2aa75 100644
--- a/lib/libalias/alias_local.h
+++ b/lib/libalias/alias_local.h
@@ -108,10 +108,19 @@ struct alias_link *
FindUdpTcpOut(struct in_addr, struct in_addr, u_short, u_short, u_char);
struct alias_link *
-FindPptpIn(struct in_addr, struct in_addr, u_short);
+AddPptp(struct in_addr, struct in_addr, struct in_addr, u_int16_t);
struct alias_link *
-FindPptpOut(struct in_addr, struct in_addr, u_short);
+FindPptpOutByCallId(struct in_addr, struct in_addr, u_int16_t);
+
+struct alias_link *
+FindPptpInByCallId(struct in_addr, struct in_addr, u_int16_t);
+
+struct alias_link *
+FindPptpOutByPeerCallId(struct in_addr, struct in_addr, u_int16_t);
+
+struct alias_link *
+FindPptpInByPeerCallId(struct in_addr, struct in_addr, u_int16_t);
struct alias_link *
QueryUdpTcpIn (struct in_addr, struct in_addr, u_short, u_short, u_char);
@@ -159,6 +168,7 @@ void SetExpire(struct alias_link *, int);
void ClearCheckNewLink(void);
void SetLastLineCrlfTermed(struct alias_link *, int);
int GetLastLineCrlfTermed(struct alias_link *);
+void SetDestCallId(struct alias_link *, u_int16_t);
#ifndef NO_FW_PUNCH
void PunchFWHole(struct alias_link *);
#endif
@@ -180,10 +190,10 @@ void AliasHandleIrcOut(struct ip *, struct alias_link *, int);
void AliasHandleRtspOut(struct ip *, struct alias_link *, int);
/* PPTP routines */
-int PptpGetCallID(struct ip *, u_short *);
-void PptpSetCallID(struct ip *, u_short);
void AliasHandlePptpOut(struct ip *, struct alias_link *);
void AliasHandlePptpIn(struct ip *, struct alias_link *);
+int AliasHandlePptpGreOut(struct ip *);
+int AliasHandlePptpGreIn(struct ip *);
/* NetBIOS routines */
int AliasHandleUdpNbt(struct ip *, struct alias_link *, struct in_addr *, u_short);
diff --git a/lib/libalias/alias_pptp.c b/lib/libalias/alias_pptp.c
index 4df8a32..373e33f 100644
--- a/lib/libalias/alias_pptp.c
+++ b/lib/libalias/alias_pptp.c
@@ -65,9 +65,6 @@
*/
/* Includes */
-#include <ctype.h>
-#include <stdio.h>
-#include <string.h>
#include <sys/types.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
@@ -82,21 +79,14 @@
struct grehdr /* Enhanced GRE header. */
{
- u_char gh_recursion:3, /* Recursion control. */
- gh_ssr_flag:1, /* Strict source route present. */
- gh_seq_no_flag:1, /* Sequence number present. */
- gh_key_flag:1, /* Key present. */
- gh_rt_flag:1, /* Routing present. */
- gh_cksum_flag:1; /* Checksum present. */
- u_char gh_version:3, /* GRE version. */
- gh_flags:4, /* Flags. */
- gh_ack_no_flag:1; /* Acknowledgment sequence number present. */
- u_short gh_protocol; /* Protocol type. */
- u_short gh_length; /* Payload length. */
- u_short gh_call_id; /* Call ID. */
+ u_int16_t gh_flags; /* Flags. */
+ u_int16_t gh_protocol; /* Protocol type. */
+ u_int16_t gh_length; /* Payload length. */
+ u_int16_t gh_call_id; /* Call ID. */
u_int32_t gh_seq_no; /* Sequence number (optional). */
u_int32_t gh_ack_no; /* Acknowledgment number (optional). */
};
+typedef struct grehdr GreHdr;
/* The PPTP protocol ID used in the GRE 'proto' field. */
#define PPTP_GRE_PROTO 0x880b
@@ -123,7 +113,7 @@ enum {
PPTP_CallClearRequest = 12,
PPTP_CallDiscNotify = 13,
PPTP_WanErrorNotify = 14,
- PPTP_SetLinkInfo = 15,
+ PPTP_SetLinkInfo = 15
};
/* Message structures */
@@ -136,6 +126,12 @@ enum {
};
typedef struct pptpMsgHead *PptpMsgHead;
+ struct pptpCodes {
+ u_int8_t resCode; /* Result Code */
+ u_int8_t errCode; /* Error Code */
+ };
+ typedef struct pptpCodes *PptpCode;
+
struct pptpCallIds {
u_int16_t cid1; /* Call ID field #1 */
u_int16_t cid2; /* Call ID field #2 */
@@ -144,29 +140,6 @@ enum {
static PptpCallId AliasVerifyPptp(struct ip *, u_int16_t *);
-int
-PptpGetCallID(struct ip *pip,
- u_short *call_id)
-{
- struct grehdr *gr;
-
- gr = (struct grehdr *)((char *)pip + (pip->ip_hl << 2));
-
- /* Check GRE header bits. */
- if ((ntohl(*((u_int32_t *)gr)) & PPTP_INIT_MASK) == PPTP_INIT_VALUE) {
- *call_id = gr->gh_call_id;
- return 1;
- } else
- return 0;
-};
-
-void PptpSetCallID(struct ip *pip, u_short call_id)
-{
- struct grehdr *gr;
-
- gr = (struct grehdr *)((char *)pip + (pip->ip_hl << 2));
- gr->gh_call_id = call_id;
-};
void
AliasHandlePptpOut(struct ip *pip, /* IP packet to examine/patch */
@@ -174,6 +147,7 @@ AliasHandlePptpOut(struct ip *pip, /* IP packet to examine/patch */
{
struct alias_link *pptp_link;
PptpCallId cptr;
+ PptpCode codes;
u_int16_t ctl_type; /* control message type */
struct tcphdr *tc;
@@ -187,12 +161,20 @@ AliasHandlePptpOut(struct ip *pip, /* IP packet to examine/patch */
case PPTP_OutCallReply:
case PPTP_InCallRequest:
case PPTP_InCallReply:
+ /* Establish PPTP link for address and Call ID found in control message. */
+ pptp_link = AddPptp(GetOriginalAddress(link), GetDestAddress(link),
+ GetAliasAddress(link), cptr->cid1);
+ break;
case PPTP_CallClearRequest:
case PPTP_CallDiscNotify:
-
- /* Establish PPTP link for address and Call ID found in PPTP Control Msg */
- pptp_link = FindPptpOut(GetOriginalAddress(link), GetDestAddress(link),
- cptr->cid1);
+ /* Find PPTP link for address and Call ID found in control message. */
+ pptp_link = FindPptpOutByCallId(GetOriginalAddress(link),
+ GetDestAddress(link),
+ cptr->cid1);
+ break;
+ default:
+ return;
+ }
if (pptp_link != NULL) {
int accumulate = cptr->cid1;
@@ -204,11 +186,22 @@ AliasHandlePptpOut(struct ip *pip, /* IP packet to examine/patch */
tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2));
accumulate -= cptr->cid1;
ADJUST_CHECKSUM(accumulate, tc->th_sum);
+
+ switch (ctl_type) {
+ case PPTP_OutCallReply:
+ case PPTP_InCallReply:
+ codes = (PptpCode)(cptr + 1);
+ if (codes->resCode == 1) /* Connection established, */
+ SetDestCallId(pptp_link, /* note the Peer's Call ID. */
+ cptr->cid2);
+ else
+ SetExpire(pptp_link, 0); /* Connection refused. */
+ break;
+ case PPTP_CallDiscNotify: /* Connection closed. */
+ SetExpire(pptp_link, 0);
+ break;
+ }
}
- break;
- default:
- return;
- }
}
void
@@ -237,28 +230,46 @@ AliasHandlePptpIn(struct ip *pip, /* IP packet to examine/patch */
case PPTP_InCallReply:
pcall_id = &cptr->cid2;
break;
+ case PPTP_CallDiscNotify: /* Connection closed. */
+ pptp_link = FindPptpInByCallId(GetDestAddress(link),
+ GetAliasAddress(link),
+ cptr->cid1);
+ if (pptp_link != NULL)
+ SetExpire(pptp_link, 0);
+ return;
default:
return;
}
/* Find PPTP link for address and Call ID found in PPTP Control Msg */
- pptp_link = FindPptpIn(GetDestAddress(link), GetAliasAddress(link),
- *pcall_id);
+ pptp_link = FindPptpInByPeerCallId(GetDestAddress(link),
+ GetAliasAddress(link),
+ *pcall_id);
if (pptp_link != NULL) {
int accumulate = *pcall_id;
- /* alias the Call Id */
+ /* De-alias the Peer's Call Id. */
*pcall_id = GetOriginalPort(pptp_link);
/* Compute TCP checksum for modified packet */
tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2));
accumulate -= *pcall_id;
ADJUST_CHECKSUM(accumulate, tc->th_sum);
+
+ if (ctl_type == PPTP_OutCallReply || ctl_type == PPTP_InCallReply) {
+ PptpCode codes = (PptpCode)(cptr + 1);
+
+ if (codes->resCode == 1) /* Connection established, */
+ SetDestCallId(pptp_link, /* note the Call ID. */
+ cptr->cid1);
+ else
+ SetExpire(pptp_link, 0); /* Connection refused. */
+ }
}
}
-PptpCallId
+static PptpCallId
AliasVerifyPptp(struct ip *pip, u_int16_t *ptype) /* IP packet to examine/patch */
{
int hlen, tlen, dlen;
@@ -285,6 +296,71 @@ AliasVerifyPptp(struct ip *pip, u_int16_t *ptype) /* IP packet to examine/patch
if ((ntohs(hptr->msgType) != PPTP_CTRL_MSG_TYPE) ||
(ntohl(hptr->magic) != PPTP_MAGIC))
return(NULL);
+
+ /* Verify data length. */
+ if ((*ptype == PPTP_OutCallReply || *ptype == PPTP_InCallReply) &&
+ (dlen < sizeof(struct pptpMsgHead) + sizeof(struct pptpCallIds) +
+ sizeof(struct pptpCodes)))
+ return (NULL);
else
- return((PptpCallId)(((char *)hptr) + sizeof(struct pptpMsgHead)));
+ return (PptpCallId)(hptr + 1);
+}
+
+
+int
+AliasHandlePptpGreOut(struct ip *pip)
+{
+ GreHdr *gr;
+ struct alias_link *link;
+
+ gr = (GreHdr *)((char *)pip + (pip->ip_hl << 2));
+
+ /* Check GRE header bits. */
+ if ((ntohl(*((u_int32_t *)gr)) & PPTP_INIT_MASK) != PPTP_INIT_VALUE)
+ return (-1);
+
+ link = FindPptpOutByPeerCallId(pip->ip_src, pip->ip_dst, gr->gh_call_id);
+ if (link != NULL) {
+ struct in_addr alias_addr = GetAliasAddress(link);
+
+ /* Change source IP address. */
+ DifferentialChecksum(&pip->ip_sum,
+ (u_short *)&alias_addr,
+ (u_short *)&pip->ip_src,
+ 2);
+ pip->ip_src = alias_addr;
+ }
+
+ return (0);
+}
+
+
+int
+AliasHandlePptpGreIn(struct ip *pip)
+{
+ GreHdr *gr;
+ struct alias_link *link;
+
+ gr = (GreHdr *)((char *)pip + (pip->ip_hl << 2));
+
+ /* Check GRE header bits. */
+ if ((ntohl(*((u_int32_t *)gr)) & PPTP_INIT_MASK) != PPTP_INIT_VALUE)
+ return (-1);
+
+ link = FindPptpInByPeerCallId(pip->ip_src, pip->ip_dst, gr->gh_call_id);
+ if (link != NULL) {
+ struct in_addr src_addr = GetOriginalAddress(link);
+
+ /* De-alias the Peer's Call Id. */
+ gr->gh_call_id = GetOriginalPort(link);
+
+ /* Restore original IP address. */
+ DifferentialChecksum(&pip->ip_sum,
+ (u_short *)&src_addr,
+ (u_short *)&pip->ip_dst,
+ 2);
+ pip->ip_dst = src_addr;
+ }
+
+ return (0);
}
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