diff options
Diffstat (limited to 'sys/netinet/libalias/alias_pptp.c')
-rw-r--r-- | sys/netinet/libalias/alias_pptp.c | 180 |
1 files changed, 128 insertions, 52 deletions
diff --git a/sys/netinet/libalias/alias_pptp.c b/sys/netinet/libalias/alias_pptp.c index 4df8a32..373e33f 100644 --- a/sys/netinet/libalias/alias_pptp.c +++ b/sys/netinet/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); } |