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Diffstat (limited to 'sys/netinet/libalias/alias.c')
| -rw-r--r-- | sys/netinet/libalias/alias.c | 1592 |
1 files changed, 0 insertions, 1592 deletions
diff --git a/sys/netinet/libalias/alias.c b/sys/netinet/libalias/alias.c deleted file mode 100644 index cf93a74c79bb..000000000000 --- a/sys/netinet/libalias/alias.c +++ /dev/null @@ -1,1592 +0,0 @@ -/* -*- mode: c; tab-width: 8; c-basic-indent: 4; -*- */ - -/*- - * Copyright (c) 2001 Charles Mott <cm@linktel.net> - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - */ - -#include <sys/cdefs.h> -__FBSDID("$FreeBSD$"); - -/* - Alias.c provides supervisory control for the functions of the - packet aliasing software. It consists of routines to monitor - TCP connection state, protocol-specific aliasing routines, - fragment handling and the following outside world functional - interfaces: SaveFragmentPtr, GetFragmentPtr, FragmentAliasIn, - PacketAliasIn and PacketAliasOut. - - The other C program files are briefly described. The data - structure framework which holds information needed to translate - packets is encapsulated in alias_db.c. Data is accessed by - function calls, so other segments of the program need not know - about the underlying data structures. Alias_ftp.c contains - special code for modifying the ftp PORT command used to establish - data connections, while alias_irc.c does the same for IRC - DCC. Alias_util.c contains a few utility routines. - - Version 1.0 August, 1996 (cjm) - - Version 1.1 August 20, 1996 (cjm) - PPP host accepts incoming connections for ports 0 to 1023. - (Gary Roberts pointed out the need to handle incoming - connections.) - - Version 1.2 September 7, 1996 (cjm) - Fragment handling error in alias_db.c corrected. - (Tom Torrance helped fix this problem.) - - Version 1.4 September 16, 1996 (cjm) - - A more generalized method for handling incoming - connections, without the 0-1023 restriction, is - implemented in alias_db.c - - Improved ICMP support in alias.c. Traceroute - packet streams can now be correctly aliased. - - TCP connection closing logic simplified in - alias.c and now allows for additional 1 minute - "grace period" after FIN or RST is observed. - - Version 1.5 September 17, 1996 (cjm) - Corrected error in handling incoming UDP packets with 0 checksum. - (Tom Torrance helped fix this problem.) - - Version 1.6 September 18, 1996 (cjm) - Simplified ICMP aliasing scheme. Should now support - traceroute from Win95 as well as FreeBSD. - - Version 1.7 January 9, 1997 (cjm) - - Out-of-order fragment handling. - - IP checksum error fixed for ftp transfers - from aliasing host. - - Integer return codes added to all - aliasing/de-aliasing functions. - - Some obsolete comments cleaned up. - - Differential checksum computations for - IP header (TCP, UDP and ICMP were already - differential). - - Version 2.1 May 1997 (cjm) - - Added support for outgoing ICMP error - messages. - - Added two functions PacketAliasIn2() - and PacketAliasOut2() for dynamic address - control (e.g. round-robin allocation of - incoming packets). - - Version 2.2 July 1997 (cjm) - - Rationalized API function names to begin - with "PacketAlias..." - - Eliminated PacketAliasIn2() and - PacketAliasOut2() as poorly conceived. - - Version 2.3 Dec 1998 (dillon) - - Major bounds checking additions, see FreeBSD/CVS - - Version 3.1 May, 2000 (salander) - - Added hooks to handle PPTP. - - Version 3.2 July, 2000 (salander and satoh) - - Added PacketUnaliasOut routine. - - Added hooks to handle RTSP/RTP. - - See HISTORY file for additional revisions. -*/ - -#include <sys/types.h> - -#include <netinet/in_systm.h> -#include <netinet/in.h> -#include <netinet/ip.h> -#include <netinet/ip_icmp.h> -#include <netinet/tcp.h> -#include <netinet/udp.h> - -#include <stdio.h> - -#include "alias_local.h" -#include "alias.h" - -#define NETBIOS_NS_PORT_NUMBER 137 -#define NETBIOS_DGM_PORT_NUMBER 138 -#define FTP_CONTROL_PORT_NUMBER 21 -#define IRC_CONTROL_PORT_NUMBER_1 6667 -#define IRC_CONTROL_PORT_NUMBER_2 6668 -#define CUSEEME_PORT_NUMBER 7648 -#define RTSP_CONTROL_PORT_NUMBER_1 554 -#define RTSP_CONTROL_PORT_NUMBER_2 7070 -#define TFTP_PORT_NUMBER 69 -#define PPTP_CONTROL_PORT_NUMBER 1723 - - - - -/* TCP Handling Routines - - TcpMonitorIn() -- These routines monitor TCP connections, and - TcpMonitorOut() delete a link when a connection is closed. - -These routines look for SYN, FIN and RST flags to determine when TCP -connections open and close. When a TCP connection closes, the data -structure containing packet aliasing information is deleted after -a timeout period. -*/ - -/* Local prototypes */ -static void TcpMonitorIn(struct ip *, struct alias_link *); - -static void TcpMonitorOut(struct ip *, struct alias_link *); - - -static void -TcpMonitorIn(struct ip *pip, struct alias_link *link) -{ - struct tcphdr *tc; - - tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2)); - - switch (GetStateIn(link)) - { - case ALIAS_TCP_STATE_NOT_CONNECTED: - if (tc->th_flags & TH_RST) - SetStateIn(link, ALIAS_TCP_STATE_DISCONNECTED); - else if (tc->th_flags & TH_SYN) - SetStateIn(link, ALIAS_TCP_STATE_CONNECTED); - break; - case ALIAS_TCP_STATE_CONNECTED: - if (tc->th_flags & (TH_FIN | TH_RST)) - SetStateIn(link, ALIAS_TCP_STATE_DISCONNECTED); - break; - } -} - -static void -TcpMonitorOut(struct ip *pip, struct alias_link *link) -{ - struct tcphdr *tc; - - tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2)); - - switch (GetStateOut(link)) - { - case ALIAS_TCP_STATE_NOT_CONNECTED: - if (tc->th_flags & TH_RST) - SetStateOut(link, ALIAS_TCP_STATE_DISCONNECTED); - else if (tc->th_flags & TH_SYN) - SetStateOut(link, ALIAS_TCP_STATE_CONNECTED); - break; - case ALIAS_TCP_STATE_CONNECTED: - if (tc->th_flags & (TH_FIN | TH_RST)) - SetStateOut(link, ALIAS_TCP_STATE_DISCONNECTED); - break; - } -} - - - - - -/* Protocol Specific Packet Aliasing Routines - - IcmpAliasIn(), IcmpAliasIn1(), IcmpAliasIn2() - IcmpAliasOut(), IcmpAliasOut1(), IcmpAliasOut2() - ProtoAliasIn(), ProtoAliasOut() - UdpAliasIn(), UdpAliasOut() - TcpAliasIn(), TcpAliasOut() - -These routines handle protocol specific details of packet aliasing. -One may observe a certain amount of repetitive arithmetic in these -functions, the purpose of which is to compute a revised checksum -without actually summing over the entire data packet, which could be -unnecessarily time consuming. - -The purpose of the packet aliasing routines is to replace the source -address of the outgoing packet and then correctly put it back for -any incoming packets. For TCP and UDP, ports are also re-mapped. - -For ICMP echo/timestamp requests and replies, the following scheme -is used: the ID number is replaced by an alias for the outgoing -packet. - -ICMP error messages are handled by looking at the IP fragment -in the data section of the message. - -For TCP and UDP protocols, a port number is chosen for an outgoing -packet, and then incoming packets are identified by IP address and -port numbers. For TCP packets, there is additional logic in the event -that sequence and ACK numbers have been altered (as in the case for -FTP data port commands). - -The port numbers used by the packet aliasing module are not true -ports in the Unix sense. No sockets are actually bound to ports. -They are more correctly thought of as placeholders. - -All packets go through the aliasing mechanism, whether they come from -the gateway machine or other machines on a local area network. -*/ - - -/* Local prototypes */ -static int IcmpAliasIn1(struct ip *); -static int IcmpAliasIn2(struct ip *); -static int IcmpAliasIn (struct ip *); - -static int IcmpAliasOut1(struct ip *); -static int IcmpAliasOut2(struct ip *); -static int IcmpAliasOut (struct ip *); - -static int ProtoAliasIn(struct ip *); -static int ProtoAliasOut(struct ip *); - -static int UdpAliasOut(struct ip *); -static int UdpAliasIn (struct ip *); - -static int TcpAliasOut(struct ip *, int); -static int TcpAliasIn (struct ip *); - - -static int -IcmpAliasIn1(struct ip *pip) -{ -/* - De-alias incoming echo and timestamp replies. - Alias incoming echo and timestamp requests. -*/ - struct alias_link *link; - struct icmp *ic; - - ic = (struct icmp *) ((char *) pip + (pip->ip_hl << 2)); - -/* Get source address from ICMP data field and restore original data */ - link = FindIcmpIn(pip->ip_src, pip->ip_dst, ic->icmp_id, 1); - if (link != NULL) - { - u_short original_id; - int accumulate; - - original_id = GetOriginalPort(link); - -/* Adjust ICMP checksum */ - accumulate = ic->icmp_id; - accumulate -= original_id; - ADJUST_CHECKSUM(accumulate, ic->icmp_cksum); - -/* Put original sequence number back in */ - ic->icmp_id = original_id; - -/* Put original address back into IP header */ - { - struct in_addr original_address; - - original_address = GetOriginalAddress(link); - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_dst, - 2); - pip->ip_dst = original_address; - } - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - -static int -IcmpAliasIn2(struct ip *pip) -{ -/* - Alias incoming ICMP error messages containing - IP header and first 64 bits of datagram. -*/ - struct ip *ip; - struct icmp *ic, *ic2; - struct udphdr *ud; - struct tcphdr *tc; - struct alias_link *link; - - ic = (struct icmp *) ((char *) pip + (pip->ip_hl << 2)); - ip = &ic->icmp_ip; - - ud = (struct udphdr *) ((char *) ip + (ip->ip_hl <<2)); - tc = (struct tcphdr *) ud; - ic2 = (struct icmp *) ud; - - if (ip->ip_p == IPPROTO_UDP) - link = FindUdpTcpIn(ip->ip_dst, ip->ip_src, - ud->uh_dport, ud->uh_sport, - IPPROTO_UDP, 0); - else if (ip->ip_p == IPPROTO_TCP) - link = FindUdpTcpIn(ip->ip_dst, ip->ip_src, - tc->th_dport, tc->th_sport, - IPPROTO_TCP, 0); - else if (ip->ip_p == IPPROTO_ICMP) { - if (ic2->icmp_type == ICMP_ECHO || ic2->icmp_type == ICMP_TSTAMP) - link = FindIcmpIn(ip->ip_dst, ip->ip_src, ic2->icmp_id, 0); - else - link = NULL; - } else - link = NULL; - - if (link != NULL) - { - if (ip->ip_p == IPPROTO_UDP || ip->ip_p == IPPROTO_TCP) - { - u_short *sptr; - int accumulate, accumulate2; - struct in_addr original_address; - u_short original_port; - - original_address = GetOriginalAddress(link); - original_port = GetOriginalPort(link); - -/* Adjust ICMP checksum */ - sptr = (u_short *) &(ip->ip_src); - accumulate = *sptr++; - accumulate += *sptr; - sptr = (u_short *) &original_address; - accumulate -= *sptr++; - accumulate -= *sptr; - accumulate += ud->uh_sport; - accumulate -= original_port; - accumulate2 = accumulate; - accumulate2 += ip->ip_sum; - ADJUST_CHECKSUM(accumulate, ip->ip_sum); - accumulate2 -= ip->ip_sum; - ADJUST_CHECKSUM(accumulate2, ic->icmp_cksum); - -/* Un-alias address in IP header */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_dst, - 2); - pip->ip_dst = original_address; - -/* Un-alias address and port number of original IP packet -fragment contained in ICMP data section */ - ip->ip_src = original_address; - ud->uh_sport = original_port; - } - else if (ip->ip_p == IPPROTO_ICMP) - { - u_short *sptr; - int accumulate, accumulate2; - struct in_addr original_address; - u_short original_id; - - original_address = GetOriginalAddress(link); - original_id = GetOriginalPort(link); - -/* Adjust ICMP checksum */ - sptr = (u_short *) &(ip->ip_src); - accumulate = *sptr++; - accumulate += *sptr; - sptr = (u_short *) &original_address; - accumulate -= *sptr++; - accumulate -= *sptr; - accumulate += ic2->icmp_id; - accumulate -= original_id; - accumulate2 = accumulate; - accumulate2 += ip->ip_sum; - ADJUST_CHECKSUM(accumulate, ip->ip_sum); - accumulate2 -= ip->ip_sum; - ADJUST_CHECKSUM(accumulate2, ic->icmp_cksum); - -/* Un-alias address in IP header */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_dst, - 2); - pip->ip_dst = original_address; - -/* Un-alias address of original IP packet and sequence number of - embedded ICMP datagram */ - ip->ip_src = original_address; - ic2->icmp_id = original_id; - } - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - - -static int -IcmpAliasIn(struct ip *pip) -{ - int iresult; - struct icmp *ic; - -/* Return if proxy-only mode is enabled */ - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - return PKT_ALIAS_OK; - - ic = (struct icmp *) ((char *) pip + (pip->ip_hl << 2)); - - iresult = PKT_ALIAS_IGNORED; - switch (ic->icmp_type) - { - case ICMP_ECHOREPLY: - case ICMP_TSTAMPREPLY: - if (ic->icmp_code == 0) - { - iresult = IcmpAliasIn1(pip); - } - break; - case ICMP_UNREACH: - case ICMP_SOURCEQUENCH: - case ICMP_TIMXCEED: - case ICMP_PARAMPROB: - iresult = IcmpAliasIn2(pip); - break; - case ICMP_ECHO: - case ICMP_TSTAMP: - iresult = IcmpAliasIn1(pip); - break; - } - return(iresult); -} - - -static int -IcmpAliasOut1(struct ip *pip) -{ -/* - Alias outgoing echo and timestamp requests. - De-alias outgoing echo and timestamp replies. -*/ - struct alias_link *link; - struct icmp *ic; - - ic = (struct icmp *) ((char *) pip + (pip->ip_hl << 2)); - -/* Save overwritten data for when echo packet returns */ - link = FindIcmpOut(pip->ip_src, pip->ip_dst, ic->icmp_id, 1); - if (link != NULL) - { - u_short alias_id; - int accumulate; - - alias_id = GetAliasPort(link); - -/* Since data field is being modified, adjust ICMP checksum */ - accumulate = ic->icmp_id; - accumulate -= alias_id; - ADJUST_CHECKSUM(accumulate, ic->icmp_cksum); - -/* Alias sequence number */ - ic->icmp_id = alias_id; - -/* Change source address */ - { - struct in_addr alias_address; - - alias_address = GetAliasAddress(link); - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; - } - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - - -static int -IcmpAliasOut2(struct ip *pip) -{ -/* - Alias outgoing ICMP error messages containing - IP header and first 64 bits of datagram. -*/ - struct ip *ip; - struct icmp *ic, *ic2; - struct udphdr *ud; - struct tcphdr *tc; - struct alias_link *link; - - ic = (struct icmp *) ((char *) pip + (pip->ip_hl << 2)); - ip = &ic->icmp_ip; - - ud = (struct udphdr *) ((char *) ip + (ip->ip_hl <<2)); - tc = (struct tcphdr *) ud; - ic2 = (struct icmp *) ud; - - if (ip->ip_p == IPPROTO_UDP) - link = FindUdpTcpOut(ip->ip_dst, ip->ip_src, - ud->uh_dport, ud->uh_sport, - IPPROTO_UDP, 0); - else if (ip->ip_p == IPPROTO_TCP) - link = FindUdpTcpOut(ip->ip_dst, ip->ip_src, - tc->th_dport, tc->th_sport, - IPPROTO_TCP, 0); - else if (ip->ip_p == IPPROTO_ICMP) { - if (ic2->icmp_type == ICMP_ECHO || ic2->icmp_type == ICMP_TSTAMP) - link = FindIcmpOut(ip->ip_dst, ip->ip_src, ic2->icmp_id, 0); - else - link = NULL; - } else - link = NULL; - - if (link != NULL) - { - if (ip->ip_p == IPPROTO_UDP || ip->ip_p == IPPROTO_TCP) - { - u_short *sptr; - int accumulate; - struct in_addr alias_address; - u_short alias_port; - - alias_address = GetAliasAddress(link); - alias_port = GetAliasPort(link); - -/* Adjust ICMP checksum */ - sptr = (u_short *) &(ip->ip_dst); - accumulate = *sptr++; - accumulate += *sptr; - sptr = (u_short *) &alias_address; - accumulate -= *sptr++; - accumulate -= *sptr; - accumulate += ud->uh_dport; - accumulate -= alias_port; - ADJUST_CHECKSUM(accumulate, ic->icmp_cksum); - -/* - * Alias address in IP header if it comes from the host - * the original TCP/UDP packet was destined for. - */ - if (pip->ip_src.s_addr == ip->ip_dst.s_addr) { - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; - } - -/* Alias address and port number of original IP packet -fragment contained in ICMP data section */ - ip->ip_dst = alias_address; - ud->uh_dport = alias_port; - } - else if (ip->ip_p == IPPROTO_ICMP) - { - u_short *sptr; - int accumulate; - struct in_addr alias_address; - u_short alias_id; - - alias_address = GetAliasAddress(link); - alias_id = GetAliasPort(link); - -/* Adjust ICMP checksum */ - sptr = (u_short *) &(ip->ip_dst); - accumulate = *sptr++; - accumulate += *sptr; - sptr = (u_short *) &alias_address; - accumulate -= *sptr++; - accumulate -= *sptr; - accumulate += ic2->icmp_id; - accumulate -= alias_id; - ADJUST_CHECKSUM(accumulate, ic->icmp_cksum); - -/* - * Alias address in IP header if it comes from the host - * the original ICMP message was destined for. - */ - if (pip->ip_src.s_addr == ip->ip_dst.s_addr) { - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; - } - -/* Alias address of original IP packet and sequence number of - embedded ICMP datagram */ - ip->ip_dst = alias_address; - ic2->icmp_id = alias_id; - } - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - - -static int -IcmpAliasOut(struct ip *pip) -{ - int iresult; - struct icmp *ic; - -/* Return if proxy-only mode is enabled */ - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - return PKT_ALIAS_OK; - - ic = (struct icmp *) ((char *) pip + (pip->ip_hl << 2)); - - iresult = PKT_ALIAS_IGNORED; - switch (ic->icmp_type) - { - case ICMP_ECHO: - case ICMP_TSTAMP: - if (ic->icmp_code == 0) - { - iresult = IcmpAliasOut1(pip); - } - break; - case ICMP_UNREACH: - case ICMP_SOURCEQUENCH: - case ICMP_TIMXCEED: - case ICMP_PARAMPROB: - iresult = IcmpAliasOut2(pip); - break; - case ICMP_ECHOREPLY: - case ICMP_TSTAMPREPLY: - iresult = IcmpAliasOut1(pip); - } - return(iresult); -} - - - -static int -ProtoAliasIn(struct ip *pip) -{ -/* - Handle incoming IP packets. The - only thing which is done in this case is to alias - the dest IP address of the packet to our inside - machine. -*/ - struct alias_link *link; - -/* Return if proxy-only mode is enabled */ - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - return PKT_ALIAS_OK; - - link = FindProtoIn(pip->ip_src, pip->ip_dst, pip->ip_p); - if (link != NULL) - { - struct in_addr original_address; - - original_address = GetOriginalAddress(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); - } - return(PKT_ALIAS_IGNORED); -} - - -static int -ProtoAliasOut(struct ip *pip) -{ -/* - Handle outgoing IP packets. The - only thing which is done in this case is to alias - the source IP address of the packet. -*/ - struct alias_link *link; - -/* Return if proxy-only mode is enabled */ - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - return PKT_ALIAS_OK; - - link = FindProtoOut(pip->ip_src, pip->ip_dst, pip->ip_p); - if (link != NULL) - { - struct in_addr alias_address; - - alias_address = GetAliasAddress(link); - -/* Change source address */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - - -static int -UdpAliasIn(struct ip *pip) -{ - struct udphdr *ud; - struct alias_link *link; - -/* Return if proxy-only mode is enabled */ - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - return PKT_ALIAS_OK; - - ud = (struct udphdr *) ((char *) pip + (pip->ip_hl << 2)); - - link = FindUdpTcpIn(pip->ip_src, pip->ip_dst, - ud->uh_sport, ud->uh_dport, - IPPROTO_UDP, 1); - if (link != NULL) - { - struct in_addr alias_address; - struct in_addr original_address; - u_short alias_port; - int accumulate; - u_short *sptr; - int r = 0; - - alias_address = GetAliasAddress(link); - original_address = GetOriginalAddress(link); - alias_port = ud->uh_dport; - ud->uh_dport = GetOriginalPort(link); - -/* Special processing for IP encoding protocols */ - if (ntohs(ud->uh_dport) == CUSEEME_PORT_NUMBER) - AliasHandleCUSeeMeIn(pip, original_address); -/* If NETBIOS Datagram, It should be alias address in UDP Data, too */ - else if (ntohs(ud->uh_dport) == NETBIOS_DGM_PORT_NUMBER - || ntohs(ud->uh_sport) == NETBIOS_DGM_PORT_NUMBER) - r = AliasHandleUdpNbt(pip, link, &original_address, ud->uh_dport); - else if (ntohs(ud->uh_dport) == NETBIOS_NS_PORT_NUMBER - || ntohs(ud->uh_sport) == NETBIOS_NS_PORT_NUMBER) - r = AliasHandleUdpNbtNS(pip, link, &alias_address, &alias_port, - &original_address, &ud->uh_dport); - -/* If UDP checksum is not zero, then adjust since destination port */ -/* is being unaliased and destination address is being altered. */ - if (ud->uh_sum != 0) - { - accumulate = alias_port; - accumulate -= ud->uh_dport; - sptr = (u_short *) &alias_address; - accumulate += *sptr++; - accumulate += *sptr; - sptr = (u_short *) &original_address; - accumulate -= *sptr++; - accumulate -= *sptr; - ADJUST_CHECKSUM(accumulate, ud->uh_sum); - } - -/* Restore original IP address */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_dst, - 2); - pip->ip_dst = original_address; - - /* - * If we cannot figure out the packet, ignore it. - */ - if (r < 0) - return(PKT_ALIAS_IGNORED); - else - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - -static int -UdpAliasOut(struct ip *pip) -{ - struct udphdr *ud; - struct alias_link *link; - -/* Return if proxy-only mode is enabled */ - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - return PKT_ALIAS_OK; - - ud = (struct udphdr *) ((char *) pip + (pip->ip_hl << 2)); - - link = FindUdpTcpOut(pip->ip_src, pip->ip_dst, - ud->uh_sport, ud->uh_dport, - IPPROTO_UDP, 1); - if (link != NULL) - { - u_short alias_port; - struct in_addr alias_address; - - alias_address = GetAliasAddress(link); - alias_port = GetAliasPort(link); - -/* Special processing for IP encoding protocols */ - if (ntohs(ud->uh_dport) == CUSEEME_PORT_NUMBER) - AliasHandleCUSeeMeOut(pip, link); -/* If NETBIOS Datagram, It should be alias address in UDP Data, too */ - else if (ntohs(ud->uh_dport) == NETBIOS_DGM_PORT_NUMBER - || ntohs(ud->uh_sport) == NETBIOS_DGM_PORT_NUMBER) - AliasHandleUdpNbt(pip, link, &alias_address, alias_port); - else if (ntohs(ud->uh_dport) == NETBIOS_NS_PORT_NUMBER - || ntohs(ud->uh_sport) == NETBIOS_NS_PORT_NUMBER) - AliasHandleUdpNbtNS(pip, link, &pip->ip_src, &ud->uh_sport, - &alias_address, &alias_port); -/* - * We don't know in advance what TID the TFTP server will choose, - * so we create a wilcard link (destination port is unspecified) - * that will match any TID from a given destination. - */ - else if (ntohs(ud->uh_dport) == TFTP_PORT_NUMBER) - FindRtspOut(pip->ip_src, pip->ip_dst, - ud->uh_sport, alias_port, IPPROTO_UDP); - -/* If UDP checksum is not zero, adjust since source port is */ -/* being aliased and source address is being altered */ - if (ud->uh_sum != 0) - { - int accumulate; - u_short *sptr; - - accumulate = ud->uh_sport; - accumulate -= alias_port; - sptr = (u_short *) &(pip->ip_src); - accumulate += *sptr++; - accumulate += *sptr; - sptr = (u_short *) &alias_address; - accumulate -= *sptr++; - accumulate -= *sptr; - ADJUST_CHECKSUM(accumulate, ud->uh_sum); - } - -/* Put alias port in UDP header */ - ud->uh_sport = alias_port; - -/* Change source address */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - - - -static int -TcpAliasIn(struct ip *pip) -{ - struct tcphdr *tc; - struct alias_link *link; - - tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2)); - - link = FindUdpTcpIn(pip->ip_src, pip->ip_dst, - tc->th_sport, tc->th_dport, - IPPROTO_TCP, - !(packetAliasMode & PKT_ALIAS_PROXY_ONLY)); - if (link != NULL) - { - struct in_addr alias_address; - struct in_addr original_address; - struct in_addr proxy_address; - u_short alias_port; - u_short proxy_port; - int accumulate; - u_short *sptr; - -/* Special processing for IP encoding protocols */ - if (ntohs(tc->th_dport) == PPTP_CONTROL_PORT_NUMBER - || ntohs(tc->th_sport) == PPTP_CONTROL_PORT_NUMBER) - AliasHandlePptpIn(pip, link); - else if (skinnyPort != 0 && (ntohs(tc->th_dport) == skinnyPort - || ntohs(tc->th_sport) == skinnyPort)) - AliasHandleSkinny(pip, link); - - alias_address = GetAliasAddress(link); - original_address = GetOriginalAddress(link); - proxy_address = GetProxyAddress(link); - alias_port = tc->th_dport; - tc->th_dport = GetOriginalPort(link); - proxy_port = GetProxyPort(link); - -/* Adjust TCP checksum since destination port is being unaliased */ -/* and destination port is being altered. */ - accumulate = alias_port; - accumulate -= tc->th_dport; - sptr = (u_short *) &alias_address; - accumulate += *sptr++; - accumulate += *sptr; - sptr = (u_short *) &original_address; - accumulate -= *sptr++; - accumulate -= *sptr; - -/* If this is a proxy, then modify the TCP source port and - checksum accumulation */ - if (proxy_port != 0) - { - accumulate += tc->th_sport; - tc->th_sport = proxy_port; - accumulate -= tc->th_sport; - - sptr = (u_short *) &pip->ip_src; - accumulate += *sptr++; - accumulate += *sptr; - sptr = (u_short *) &proxy_address; - accumulate -= *sptr++; - accumulate -= *sptr; - } - -/* See if ACK number needs to be modified */ - if (GetAckModified(link) == 1) - { - int delta; - - delta = GetDeltaAckIn(pip, link); - if (delta != 0) - { - sptr = (u_short *) &tc->th_ack; - accumulate += *sptr++; - accumulate += *sptr; - tc->th_ack = htonl(ntohl(tc->th_ack) - delta); - sptr = (u_short *) &tc->th_ack; - accumulate -= *sptr++; - accumulate -= *sptr; - } - } - - ADJUST_CHECKSUM(accumulate, tc->th_sum); - -/* Restore original IP address */ - sptr = (u_short *) &pip->ip_dst; - accumulate = *sptr++; - accumulate += *sptr; - pip->ip_dst = original_address; - sptr = (u_short *) &pip->ip_dst; - accumulate -= *sptr++; - accumulate -= *sptr; - -/* If this is a transparent proxy packet, then modify the source - address */ - if (proxy_address.s_addr != 0) - { - sptr = (u_short *) &pip->ip_src; - accumulate += *sptr++; - accumulate += *sptr; - pip->ip_src = proxy_address; - sptr = (u_short *) &pip->ip_src; - accumulate -= *sptr++; - accumulate -= *sptr; - } - - ADJUST_CHECKSUM(accumulate, pip->ip_sum); - -/* Monitor TCP connection state */ - TcpMonitorIn(pip, link); - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - -static int -TcpAliasOut(struct ip *pip, int maxpacketsize) -{ - int proxy_type; - u_short dest_port; - u_short proxy_server_port; - struct in_addr dest_address; - struct in_addr proxy_server_address; - struct tcphdr *tc; - struct alias_link *link; - - tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2)); - - proxy_type = ProxyCheck(pip, &proxy_server_address, &proxy_server_port); - - if (proxy_type == 0 && (packetAliasMode & PKT_ALIAS_PROXY_ONLY)) - return PKT_ALIAS_OK; - -/* If this is a transparent proxy, save original destination, - then alter the destination and adjust checksums */ - dest_port = tc->th_dport; - dest_address = pip->ip_dst; - if (proxy_type != 0) - { - int accumulate; - u_short *sptr; - - accumulate = tc->th_dport; - tc->th_dport = proxy_server_port; - accumulate -= tc->th_dport; - - sptr = (u_short *) &(pip->ip_dst); - accumulate += *sptr++; - accumulate += *sptr; - sptr = (u_short *) &proxy_server_address; - accumulate -= *sptr++; - accumulate -= *sptr; - - ADJUST_CHECKSUM(accumulate, tc->th_sum); - - sptr = (u_short *) &(pip->ip_dst); - accumulate = *sptr++; - accumulate += *sptr; - pip->ip_dst = proxy_server_address; - sptr = (u_short *) &(pip->ip_dst); - accumulate -= *sptr++; - accumulate -= *sptr; - - ADJUST_CHECKSUM(accumulate, pip->ip_sum); - } - - link = FindUdpTcpOut(pip->ip_src, pip->ip_dst, - tc->th_sport, tc->th_dport, - IPPROTO_TCP, 1); - if (link !=NULL) - { - u_short alias_port; - struct in_addr alias_address; - int accumulate; - u_short *sptr; - -/* Save original destination address, if this is a proxy packet. - Also modify packet to include destination encoding. This may - change the size of IP header. */ - if (proxy_type != 0) - { - SetProxyPort(link, dest_port); - SetProxyAddress(link, dest_address); - ProxyModify(link, pip, maxpacketsize, proxy_type); - tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2)); - } - -/* Get alias address and port */ - alias_port = GetAliasPort(link); - alias_address = GetAliasAddress(link); - -/* Monitor TCP connection state */ - TcpMonitorOut(pip, link); - -/* Special processing for IP encoding protocols */ - if (ntohs(tc->th_dport) == FTP_CONTROL_PORT_NUMBER - || ntohs(tc->th_sport) == FTP_CONTROL_PORT_NUMBER) - AliasHandleFtpOut(pip, link, maxpacketsize); - else if (ntohs(tc->th_dport) == IRC_CONTROL_PORT_NUMBER_1 - || ntohs(tc->th_dport) == IRC_CONTROL_PORT_NUMBER_2) - AliasHandleIrcOut(pip, link, maxpacketsize); - else if (ntohs(tc->th_dport) == RTSP_CONTROL_PORT_NUMBER_1 - || ntohs(tc->th_sport) == RTSP_CONTROL_PORT_NUMBER_1 - || ntohs(tc->th_dport) == RTSP_CONTROL_PORT_NUMBER_2 - || ntohs(tc->th_sport) == RTSP_CONTROL_PORT_NUMBER_2) - AliasHandleRtspOut(pip, link, maxpacketsize); - else if (ntohs(tc->th_dport) == PPTP_CONTROL_PORT_NUMBER - || ntohs(tc->th_sport) == PPTP_CONTROL_PORT_NUMBER) - AliasHandlePptpOut(pip, link); - else if (skinnyPort != 0 && (ntohs(tc->th_sport) == skinnyPort - || ntohs(tc->th_dport) == skinnyPort)) - AliasHandleSkinny(pip, link); - -/* Adjust TCP checksum since source port is being aliased */ -/* and source address is being altered */ - accumulate = tc->th_sport; - tc->th_sport = alias_port; - accumulate -= tc->th_sport; - - sptr = (u_short *) &(pip->ip_src); - accumulate += *sptr++; - accumulate += *sptr; - sptr = (u_short *) &alias_address; - accumulate -= *sptr++; - accumulate -= *sptr; - -/* Modify sequence number if necessary */ - if (GetAckModified(link) == 1) - { - int delta; - - delta = GetDeltaSeqOut(pip, link); - if (delta != 0) - { - sptr = (u_short *) &tc->th_seq; - accumulate += *sptr++; - accumulate += *sptr; - tc->th_seq = htonl(ntohl(tc->th_seq) + delta); - sptr = (u_short *) &tc->th_seq; - accumulate -= *sptr++; - accumulate -= *sptr; - } - } - - ADJUST_CHECKSUM(accumulate, tc->th_sum); - -/* Change source address */ - sptr = (u_short *) &(pip->ip_src); - accumulate = *sptr++; - accumulate += *sptr; - pip->ip_src = alias_address; - sptr = (u_short *) &(pip->ip_src); - accumulate -= *sptr++; - accumulate -= *sptr; - - ADJUST_CHECKSUM(accumulate, pip->ip_sum); - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_IGNORED); -} - - - - -/* Fragment Handling - - FragmentIn() - FragmentOut() - -The packet aliasing module has a limited ability for handling IP -fragments. If the ICMP, TCP or UDP header is in the first fragment -received, then the ID number of the IP packet is saved, and other -fragments are identified according to their ID number and IP address -they were sent from. Pointers to unresolved fragments can also be -saved and recalled when a header fragment is seen. -*/ - -/* Local prototypes */ -static int FragmentIn(struct ip *); -static int FragmentOut(struct ip *); - - -static int -FragmentIn(struct ip *pip) -{ - struct alias_link *link; - - link = FindFragmentIn2(pip->ip_src, pip->ip_dst, pip->ip_id); - if (link != NULL) - { - struct in_addr original_address; - - GetFragmentAddr(link, &original_address); - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_dst, - 2); - pip->ip_dst = original_address; - - return(PKT_ALIAS_OK); - } - return(PKT_ALIAS_UNRESOLVED_FRAGMENT); -} - - -static int -FragmentOut(struct ip *pip) -{ - struct in_addr alias_address; - - alias_address = FindAliasAddress(pip->ip_src); - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; - - return(PKT_ALIAS_OK); -} - - - - - - -/* Outside World Access - - PacketAliasSaveFragment() - PacketAliasGetFragment() - PacketAliasFragmentIn() - PacketAliasIn() - PacketAliasOut() - PacketUnaliasOut() - -(prototypes in alias.h) -*/ - - -int -PacketAliasSaveFragment(char *ptr) -{ - int iresult; - struct alias_link *link; - struct ip *pip; - - pip = (struct ip *) ptr; - link = AddFragmentPtrLink(pip->ip_src, pip->ip_id); - iresult = PKT_ALIAS_ERROR; - if (link != NULL) - { - SetFragmentPtr(link, ptr); - iresult = PKT_ALIAS_OK; - } - return(iresult); -} - - -char * -PacketAliasGetFragment(char *ptr) -{ - struct alias_link *link; - char *fptr; - struct ip *pip; - - pip = (struct ip *) ptr; - link = FindFragmentPtr(pip->ip_src, pip->ip_id); - if (link != NULL) - { - GetFragmentPtr(link, &fptr); - SetFragmentPtr(link, NULL); - SetExpire(link, 0); /* Deletes link */ - - return(fptr); - } - else - { - return(NULL); - } -} - - -void -PacketAliasFragmentIn(char *ptr, /* Points to correctly de-aliased - header fragment */ - char *ptr_fragment /* Points to fragment which must - be de-aliased */ - ) -{ - struct ip *pip; - struct ip *fpip; - - pip = (struct ip *) ptr; - fpip = (struct ip *) ptr_fragment; - - DifferentialChecksum(&fpip->ip_sum, - (u_short *) &pip->ip_dst, - (u_short *) &fpip->ip_dst, - 2); - fpip->ip_dst = pip->ip_dst; -} - - -int -PacketAliasIn(char *ptr, int maxpacketsize) -{ - struct in_addr alias_addr; - struct ip *pip; - int iresult; - - if (packetAliasMode & PKT_ALIAS_REVERSE) { - packetAliasMode &= ~PKT_ALIAS_REVERSE; - iresult = PacketAliasOut(ptr, maxpacketsize); - packetAliasMode |= PKT_ALIAS_REVERSE; - return iresult; - } - - HouseKeeping(); - ClearCheckNewLink(); - pip = (struct ip *) ptr; - alias_addr = pip->ip_dst; - - /* Defense against mangled packets */ - if (ntohs(pip->ip_len) > maxpacketsize - || (pip->ip_hl<<2) > maxpacketsize) - return PKT_ALIAS_IGNORED; - - iresult = PKT_ALIAS_IGNORED; - if ( (ntohs(pip->ip_off) & IP_OFFMASK) == 0 ) - { - switch (pip->ip_p) - { - case IPPROTO_ICMP: - iresult = IcmpAliasIn(pip); - break; - case IPPROTO_UDP: - iresult = UdpAliasIn(pip); - break; - case IPPROTO_TCP: - iresult = TcpAliasIn(pip); - break; - case IPPROTO_GRE: - if (packetAliasMode & PKT_ALIAS_PROXY_ONLY || - AliasHandlePptpGreIn(pip) == 0) - iresult = PKT_ALIAS_OK; - else - iresult = ProtoAliasIn(pip); - break; - default: - iresult = ProtoAliasIn(pip); - break; - } - - if (ntohs(pip->ip_off) & IP_MF) - { - struct alias_link *link; - - link = FindFragmentIn1(pip->ip_src, alias_addr, pip->ip_id); - if (link != NULL) - { - iresult = PKT_ALIAS_FOUND_HEADER_FRAGMENT; - SetFragmentAddr(link, pip->ip_dst); - } - else - { - iresult = PKT_ALIAS_ERROR; - } - } - } - else - { - iresult = FragmentIn(pip); - } - - return(iresult); -} - - - -/* Unregistered address ranges */ - -/* 10.0.0.0 -> 10.255.255.255 */ -#define UNREG_ADDR_A_LOWER 0x0a000000 -#define UNREG_ADDR_A_UPPER 0x0affffff - -/* 172.16.0.0 -> 172.31.255.255 */ -#define UNREG_ADDR_B_LOWER 0xac100000 -#define UNREG_ADDR_B_UPPER 0xac1fffff - -/* 192.168.0.0 -> 192.168.255.255 */ -#define UNREG_ADDR_C_LOWER 0xc0a80000 -#define UNREG_ADDR_C_UPPER 0xc0a8ffff - -int -PacketAliasOut(char *ptr, /* valid IP packet */ - int maxpacketsize /* How much the packet data may grow - (FTP and IRC inline changes) */ - ) -{ - int iresult; - struct in_addr addr_save; - struct ip *pip; - - if (packetAliasMode & PKT_ALIAS_REVERSE) { - packetAliasMode &= ~PKT_ALIAS_REVERSE; - iresult = PacketAliasIn(ptr, maxpacketsize); - packetAliasMode |= PKT_ALIAS_REVERSE; - return iresult; - } - - HouseKeeping(); - ClearCheckNewLink(); - pip = (struct ip *) ptr; - - /* Defense against mangled packets */ - if (ntohs(pip->ip_len) > maxpacketsize - || (pip->ip_hl<<2) > maxpacketsize) - return PKT_ALIAS_IGNORED; - - addr_save = GetDefaultAliasAddress(); - if (packetAliasMode & PKT_ALIAS_UNREGISTERED_ONLY) - { - u_long addr; - int iclass; - - iclass = 0; - addr = ntohl(pip->ip_src.s_addr); - if (addr >= UNREG_ADDR_C_LOWER && addr <= UNREG_ADDR_C_UPPER) - iclass = 3; - else if (addr >= UNREG_ADDR_B_LOWER && addr <= UNREG_ADDR_B_UPPER) - iclass = 2; - else if (addr >= UNREG_ADDR_A_LOWER && addr <= UNREG_ADDR_A_UPPER) - iclass = 1; - - if (iclass == 0) - { - SetDefaultAliasAddress(pip->ip_src); - } - } - else if (packetAliasMode & PKT_ALIAS_PROXY_ONLY) - { - SetDefaultAliasAddress(pip->ip_src); - } - - iresult = PKT_ALIAS_IGNORED; - if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0) - { - switch (pip->ip_p) - { - case IPPROTO_ICMP: - iresult = IcmpAliasOut(pip); - break; - case IPPROTO_UDP: - iresult = UdpAliasOut(pip); - break; - 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; - } - } - else - { - iresult = FragmentOut(pip); - } - - SetDefaultAliasAddress(addr_save); - return(iresult); -} - -int -PacketUnaliasOut(char *ptr, /* valid IP packet */ - int maxpacketsize /* for error checking */ - ) -{ - struct ip *pip; - struct icmp *ic; - struct udphdr *ud; - struct tcphdr *tc; - struct alias_link *link; - int iresult = PKT_ALIAS_IGNORED; - - pip = (struct ip *) ptr; - - /* Defense against mangled packets */ - if (ntohs(pip->ip_len) > maxpacketsize - || (pip->ip_hl<<2) > maxpacketsize) - return(iresult); - - ud = (struct udphdr *) ((char *) pip + (pip->ip_hl << 2)); - tc = (struct tcphdr *) ud; - ic = (struct icmp *) ud; - - /* Find a link */ - if (pip->ip_p == IPPROTO_UDP) - link = FindUdpTcpIn(pip->ip_dst, pip->ip_src, - ud->uh_dport, ud->uh_sport, - IPPROTO_UDP, 0); - else if (pip->ip_p == IPPROTO_TCP) - link = FindUdpTcpIn(pip->ip_dst, pip->ip_src, - tc->th_dport, tc->th_sport, - IPPROTO_TCP, 0); - else if (pip->ip_p == IPPROTO_ICMP) - link = FindIcmpIn(pip->ip_dst, pip->ip_src, ic->icmp_id, 0); - else - link = NULL; - - /* Change it from an aliased packet to an unaliased packet */ - if (link != NULL) - { - if (pip->ip_p == IPPROTO_UDP || pip->ip_p == IPPROTO_TCP) - { - u_short *sptr; - int accumulate; - struct in_addr original_address; - u_short original_port; - - original_address = GetOriginalAddress(link); - original_port = GetOriginalPort(link); - - /* Adjust TCP/UDP checksum */ - sptr = (u_short *) &(pip->ip_src); - accumulate = *sptr++; - accumulate += *sptr; - sptr = (u_short *) &original_address; - accumulate -= *sptr++; - accumulate -= *sptr; - - if (pip->ip_p == IPPROTO_UDP) { - accumulate += ud->uh_sport; - accumulate -= original_port; - ADJUST_CHECKSUM(accumulate, ud->uh_sum); - } else { - accumulate += tc->th_sport; - accumulate -= original_port; - ADJUST_CHECKSUM(accumulate, tc->th_sum); - } - - /* Adjust IP checksum */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_src, - 2); - - /* Un-alias source address and port number */ - pip->ip_src = original_address; - if (pip->ip_p == IPPROTO_UDP) - ud->uh_sport = original_port; - else - tc->th_sport = original_port; - - iresult = PKT_ALIAS_OK; - - } else if (pip->ip_p == IPPROTO_ICMP) { - - u_short *sptr; - int accumulate; - struct in_addr original_address; - u_short original_id; - - original_address = GetOriginalAddress(link); - original_id = GetOriginalPort(link); - - /* Adjust ICMP checksum */ - sptr = (u_short *) &(pip->ip_src); - accumulate = *sptr++; - accumulate += *sptr; - sptr = (u_short *) &original_address; - accumulate -= *sptr++; - accumulate -= *sptr; - accumulate += ic->icmp_id; - accumulate -= original_id; - ADJUST_CHECKSUM(accumulate, ic->icmp_cksum); - - /* Adjust IP checksum */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &original_address, - (u_short *) &pip->ip_src, - 2); - - /* Un-alias source address and port number */ - pip->ip_src = original_address; - ic->icmp_id = original_id; - - iresult = PKT_ALIAS_OK; - } - } - return(iresult); - -} |