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freebsd-nq/sbin/natd/natd.c
Mark Johnston 517373f723 natd: Remove uneeded in_cksum.h includes 
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
2021-11-24 13:31:16 -05:00

2043 lines
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/*
* natd - Network Address Translation Daemon for FreeBSD.
*
* This software is provided free of charge, with no
* warranty of any kind, either expressed or implied.
* Use at your own risk.
*
* You may copy, modify and distribute this software (natd.c) freely.
*
* Ari Suutari <suutari@iki.fi>
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define SYSLOG_NAMES
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <arpa/inet.h>
#include <alias.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "natd.h"
struct instance {
const char *name;
struct libalias *la;
LIST_ENTRY(instance) list;
int ifIndex;
int assignAliasAddr;
char* ifName;
int logDropped;
u_short inPort;
u_short outPort;
u_short inOutPort;
struct in_addr aliasAddr;
int ifMTU;
int aliasOverhead;
int dropIgnoredIncoming;
int divertIn;
int divertOut;
int divertInOut;
};
static LIST_HEAD(, instance) root = LIST_HEAD_INITIALIZER(root);
struct libalias *mla;
static struct instance *mip;
static int ninstance = 1;
/*
* Default values for input and output
* divert socket ports.
*/
#define DEFAULT_SERVICE "natd"
/*
* Definition of a port range, and macros to deal with values.
* FORMAT: HI 16-bits == first port in range, 0 == all ports.
* LO 16-bits == number of ports in range
* NOTES: - Port values are not stored in network byte order.
*/
typedef u_long port_range;
#define GETLOPORT(x) ((x) >> 0x10)
#define GETNUMPORTS(x) ((x) & 0x0000ffff)
#define GETHIPORT(x) (GETLOPORT((x)) + GETNUMPORTS((x)))
/* Set y to be the low-port value in port_range variable x. */
#define SETLOPORT(x,y) ((x) = ((x) & 0x0000ffff) | ((y) << 0x10))
/* Set y to be the number of ports in port_range variable x. */
#define SETNUMPORTS(x,y) ((x) = ((x) & 0xffff0000) | (y))
/*
* Function prototypes.
*/
static void DoAliasing (int fd, int direction);
static void DaemonMode (void);
static void HandleRoutingInfo (int fd);
static void Usage (void);
static char* FormatPacket (struct ip*);
static void PrintPacket (struct ip*);
static void SyslogPacket (struct ip*, int priority, const char *label);
static int SetAliasAddressFromIfName (const char *ifName);
static void InitiateShutdown (int);
static void Shutdown (int);
static void RefreshAddr (int);
static void ParseOption (const char* option, const char* parms);
static void ReadConfigFile (const char* fileName);
static void SetupPortRedirect (const char* parms);
static void SetupProtoRedirect(const char* parms);
static void SetupAddressRedirect (const char* parms);
static void StrToAddr (const char* str, struct in_addr* addr);
static u_short StrToPort (const char* str, const char* proto);
static int StrToPortRange (const char* str, const char* proto, port_range *portRange);
static int StrToProto (const char* str);
static int StrToAddrAndPortRange (char* str, struct in_addr* addr, char* proto, port_range *portRange);
static void ParseArgs (int argc, char** argv);
static void SetupPunchFW(const char *strValue);
static void SetupSkinnyPort(const char *strValue);
static void NewInstance(const char *name);
static void DoGlobal (int fd);
static int CheckIpfwRulenum(unsigned int rnum);
/*
* Globals.
*/
static int verbose;
static int background;
static int running;
static int logFacility;
static int dynamicMode;
static int icmpSock;
static int logIpfwDenied;
static const char* pidName;
static int routeSock;
static int globalPort;
static int divertGlobal;
static int exitDelay;
int main (int argc, char** argv)
{
struct sockaddr_in addr;
fd_set readMask;
int fdMax;
int rval;
/*
* Initialize packet aliasing software.
* Done already here to be able to alter option bits
* during command line and configuration file processing.
*/
NewInstance("default");
/*
* Parse options.
*/
verbose = 0;
background = 0;
running = 1;
dynamicMode = 0;
logFacility = LOG_DAEMON;
logIpfwDenied = -1;
pidName = PIDFILE;
routeSock = -1;
icmpSock = -1;
fdMax = -1;
divertGlobal = -1;
exitDelay = EXIT_DELAY;
ParseArgs (argc, argv);
/*
* Log ipfw(8) denied packets by default in verbose mode.
*/
if (logIpfwDenied == -1)
logIpfwDenied = verbose;
/*
* Open syslog channel.
*/
openlog ("natd", LOG_CONS | LOG_PID | (verbose ? LOG_PERROR : 0),
logFacility);
LIST_FOREACH(mip, &root, list) {
mla = mip->la;
/*
* If not doing the transparent proxying only,
* check that valid aliasing address has been given.
*/
if (mip->aliasAddr.s_addr == INADDR_NONE && mip->ifName == NULL &&
!(LibAliasSetMode(mla, 0,0) & PKT_ALIAS_PROXY_ONLY))
errx (1, "instance %s: aliasing address not given", mip->name);
if (mip->aliasAddr.s_addr != INADDR_NONE && mip->ifName != NULL)
errx (1, "both alias address and interface "
"name are not allowed");
/*
* Check that valid port number is known.
*/
if (mip->inPort != 0 || mip->outPort != 0)
if (mip->inPort == 0 || mip->outPort == 0)
errx (1, "both input and output ports are required");
if (mip->inPort == 0 && mip->outPort == 0 && mip->inOutPort == 0)
ParseOption ("port", DEFAULT_SERVICE);
/*
* Check if ignored packets should be dropped.
*/
mip->dropIgnoredIncoming = LibAliasSetMode (mla, 0, 0);
mip->dropIgnoredIncoming &= PKT_ALIAS_DENY_INCOMING;
/*
* Create divert sockets. Use only one socket if -p was specified
* on command line. Otherwise, create separate sockets for
* outgoing and incoming connections.
*/
if (mip->inOutPort) {
mip->divertInOut = socket (PF_INET, SOCK_RAW, IPPROTO_DIVERT);
if (mip->divertInOut == -1)
Quit ("Unable to create divert socket.");
if (mip->divertInOut > fdMax)
fdMax = mip->divertInOut;
mip->divertIn = -1;
mip->divertOut = -1;
/*
* Bind socket.
*/
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = mip->inOutPort;
if (bind (mip->divertInOut,
(struct sockaddr*) &addr,
sizeof addr) == -1)
Quit ("Unable to bind divert socket.");
}
else {
mip->divertIn = socket (PF_INET, SOCK_RAW, IPPROTO_DIVERT);
if (mip->divertIn == -1)
Quit ("Unable to create incoming divert socket.");
if (mip->divertIn > fdMax)
fdMax = mip->divertIn;
mip->divertOut = socket (PF_INET, SOCK_RAW, IPPROTO_DIVERT);
if (mip->divertOut == -1)
Quit ("Unable to create outgoing divert socket.");
if (mip->divertOut > fdMax)
fdMax = mip->divertOut;
mip->divertInOut = -1;
/*
* Bind divert sockets.
*/
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = mip->inPort;
if (bind (mip->divertIn,
(struct sockaddr*) &addr,
sizeof addr) == -1)
Quit ("Unable to bind incoming divert socket.");
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = mip->outPort;
if (bind (mip->divertOut,
(struct sockaddr*) &addr,
sizeof addr) == -1)
Quit ("Unable to bind outgoing divert socket.");
}
/*
* Create routing socket if interface name specified and in dynamic mode.
*/
if (mip->ifName) {
if (dynamicMode) {
if (routeSock == -1)
routeSock = socket (PF_ROUTE, SOCK_RAW, 0);
if (routeSock == -1)
Quit ("Unable to create routing info socket.");
if (routeSock > fdMax)
fdMax = routeSock;
mip->assignAliasAddr = 1;
}
else {
do {
rval = SetAliasAddressFromIfName (mip->ifName);
if (background == 0 || dynamicMode == 0)
break;
if (rval == EAGAIN)
sleep(1);
} while (rval == EAGAIN);
if (rval != 0)
exit(1);
}
}
}
if (globalPort) {
divertGlobal = socket (PF_INET, SOCK_RAW, IPPROTO_DIVERT);
if (divertGlobal == -1)
Quit ("Unable to create divert socket.");
if (divertGlobal > fdMax)
fdMax = divertGlobal;
/*
* Bind socket.
*/
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = globalPort;
if (bind (divertGlobal,
(struct sockaddr*) &addr,
sizeof addr) == -1)
Quit ("Unable to bind global divert socket.");
}
/*
* Create socket for sending ICMP messages.
*/
icmpSock = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (icmpSock == -1)
Quit ("Unable to create ICMP socket.");
/*
* And disable reads for the socket, otherwise it slowly fills
* up with received icmps which we do not use.
*/
shutdown(icmpSock, SHUT_RD);
/*
* Become a daemon unless verbose mode was requested.
*/
if (!verbose)
DaemonMode ();
/*
* Catch signals to manage shutdown and
* refresh of interface address.
*/
siginterrupt(SIGTERM, 1);
siginterrupt(SIGHUP, 1);
if (exitDelay)
signal(SIGTERM, InitiateShutdown);
else
signal(SIGTERM, Shutdown);
signal (SIGHUP, RefreshAddr);
/*
* Set alias address if it has been given.
*/
mip = LIST_FIRST(&root); /* XXX: simon */
LIST_FOREACH(mip, &root, list) {
mla = mip->la;
if (mip->aliasAddr.s_addr != INADDR_NONE)
LibAliasSetAddress (mla, mip->aliasAddr);
}
while (running) {
mip = LIST_FIRST(&root); /* XXX: simon */
if (mip->divertInOut != -1 && !mip->ifName && ninstance == 1) {
/*
* When using only one socket, just call
* DoAliasing repeatedly to process packets.
*/
DoAliasing (mip->divertInOut, DONT_KNOW);
continue;
}
/*
* Build read mask from socket descriptors to select.
*/
FD_ZERO (&readMask);
/*
* Check if new packets are available.
*/
LIST_FOREACH(mip, &root, list) {
if (mip->divertIn != -1)
FD_SET (mip->divertIn, &readMask);
if (mip->divertOut != -1)
FD_SET (mip->divertOut, &readMask);
if (mip->divertInOut != -1)
FD_SET (mip->divertInOut, &readMask);
}
/*
* Routing info is processed always.
*/
if (routeSock != -1)
FD_SET (routeSock, &readMask);
if (divertGlobal != -1)
FD_SET (divertGlobal, &readMask);
if (select (fdMax + 1,
&readMask,
NULL,
NULL,
NULL) == -1) {
if (errno == EINTR)
continue;
Quit ("Select failed.");
}
if (divertGlobal != -1)
if (FD_ISSET (divertGlobal, &readMask))
DoGlobal (divertGlobal);
LIST_FOREACH(mip, &root, list) {
mla = mip->la;
if (mip->divertIn != -1)
if (FD_ISSET (mip->divertIn, &readMask))
DoAliasing (mip->divertIn, INPUT);
if (mip->divertOut != -1)
if (FD_ISSET (mip->divertOut, &readMask))
DoAliasing (mip->divertOut, OUTPUT);
if (mip->divertInOut != -1)
if (FD_ISSET (mip->divertInOut, &readMask))
DoAliasing (mip->divertInOut, DONT_KNOW);
}
if (routeSock != -1)
if (FD_ISSET (routeSock, &readMask))
HandleRoutingInfo (routeSock);
}
if (background)
unlink (pidName);
return 0;
}
static void DaemonMode(void)
{
FILE* pidFile;
daemon (0, 0);
background = 1;
pidFile = fopen (pidName, "w");
if (pidFile) {
fprintf (pidFile, "%d\n", getpid ());
fclose (pidFile);
}
}
static void ParseArgs (int argc, char** argv)
{
int arg;
char* opt;
char parmBuf[256];
int len; /* bounds checking */
for (arg = 1; arg < argc; arg++) {
opt = argv[arg];
if (*opt != '-') {
warnx ("invalid option %s", opt);
Usage ();
}
parmBuf[0] = '\0';
len = 0;
while (arg < argc - 1) {
if (argv[arg + 1][0] == '-')
break;
if (len) {
strncat (parmBuf, " ", sizeof(parmBuf) - (len + 1));
len += strlen(parmBuf + len);
}
++arg;
strncat (parmBuf, argv[arg], sizeof(parmBuf) - (len + 1));
len += strlen(parmBuf + len);
}
ParseOption (opt + 1, (len ? parmBuf : NULL));
}
}
static void DoGlobal (int fd)
{
int bytes;
int origBytes;
char buf[IP_MAXPACKET];
struct sockaddr_in addr;
int wrote;
socklen_t addrSize;
struct ip* ip;
char msgBuf[80];
/*
* Get packet from socket.
*/
addrSize = sizeof addr;
origBytes = recvfrom (fd,
buf,
sizeof buf,
0,
(struct sockaddr*) &addr,
&addrSize);
if (origBytes == -1) {
if (errno != EINTR)
Warn ("read from divert socket failed");
return;
}
#if 0
if (mip->assignAliasAddr) {
if (SetAliasAddressFromIfName (mip->ifName) != 0)
exit(1);
mip->assignAliasAddr = 0;
}
#endif
/*
* This is an IP packet.
*/
ip = (struct ip*) buf;
if (verbose) {
/*
* Print packet direction and protocol type.
*/
printf ("Glb ");
switch (ip->ip_p) {
case IPPROTO_TCP:
printf ("[TCP] ");
break;
case IPPROTO_UDP:
printf ("[UDP] ");
break;
case IPPROTO_ICMP:
printf ("[ICMP] ");
break;
default:
printf ("[%d] ", ip->ip_p);
break;
}
/*
* Print addresses.
*/
PrintPacket (ip);
}
LIST_FOREACH(mip, &root, list) {
mla = mip->la;
if (LibAliasOutTry (mla, buf, IP_MAXPACKET, 0) != PKT_ALIAS_IGNORED)
break;
}
/*
* Length might have changed during aliasing.
*/
bytes = ntohs (ip->ip_len);
/*
* Update alias overhead size for outgoing packets.
*/
if (mip != NULL && bytes - origBytes > mip->aliasOverhead)
mip->aliasOverhead = bytes - origBytes;
if (verbose) {
/*
* Print addresses after aliasing.
*/
printf (" aliased to\n");
printf (" ");
PrintPacket (ip);
printf ("\n");
}
/*
* Put packet back for processing.
*/
wrote = sendto (fd,
buf,
bytes,
0,
(struct sockaddr*) &addr,
sizeof addr);
if (wrote != bytes) {
if (errno == EMSGSIZE && mip != NULL) {
if (mip->ifMTU != -1)
SendNeedFragIcmp (icmpSock,
(struct ip*) buf,
mip->ifMTU - mip->aliasOverhead);
}
else if (errno == EACCES && logIpfwDenied) {
sprintf (msgBuf, "failed to write packet back");
Warn (msgBuf);
}
}
}
static void DoAliasing (int fd, int direction)
{
int bytes;
int origBytes;
char buf[IP_MAXPACKET];
struct sockaddr_in addr;
int wrote;
int status;
socklen_t addrSize;
struct ip* ip;
char msgBuf[80];
int rval;
if (mip->assignAliasAddr) {
do {
rval = SetAliasAddressFromIfName (mip->ifName);
if (background == 0 || dynamicMode == 0)
break;
if (rval == EAGAIN)
sleep(1);
} while (rval == EAGAIN);
if (rval != 0)
exit(1);
mip->assignAliasAddr = 0;
}
/*
* Get packet from socket.
*/
addrSize = sizeof addr;
origBytes = recvfrom (fd,
buf,
sizeof buf,
0,
(struct sockaddr*) &addr,
&addrSize);
if (origBytes == -1) {
if (errno != EINTR)
Warn ("read from divert socket failed");
return;
}
/*
* This is an IP packet.
*/
ip = (struct ip*) buf;
if (direction == DONT_KNOW) {
if (addr.sin_addr.s_addr == INADDR_ANY)
direction = OUTPUT;
else
direction = INPUT;
}
if (verbose) {
/*
* Print packet direction and protocol type.
*/
printf (direction == OUTPUT ? "Out " : "In ");
if (ninstance > 1)
printf ("{%s}", mip->name);
switch (ip->ip_p) {
case IPPROTO_TCP:
printf ("[TCP] ");
break;
case IPPROTO_UDP:
printf ("[UDP] ");
break;
case IPPROTO_ICMP:
printf ("[ICMP] ");
break;
default:
printf ("[%d] ", ip->ip_p);
break;
}
/*
* Print addresses.
*/
PrintPacket (ip);
}
if (direction == OUTPUT) {
/*
* Outgoing packets. Do aliasing.
*/
LibAliasOut (mla, buf, IP_MAXPACKET);
}
else {
/*
* Do aliasing.
*/
status = LibAliasIn (mla, buf, IP_MAXPACKET);
if (status == PKT_ALIAS_IGNORED &&
mip->dropIgnoredIncoming) {
if (verbose)
printf (" dropped.\n");
if (mip->logDropped)
SyslogPacket (ip, LOG_WARNING, "denied");
return;
}
}
/*
* Length might have changed during aliasing.
*/
bytes = ntohs (ip->ip_len);
/*
* Update alias overhead size for outgoing packets.
*/
if (direction == OUTPUT &&
bytes - origBytes > mip->aliasOverhead)
mip->aliasOverhead = bytes - origBytes;
if (verbose) {
/*
* Print addresses after aliasing.
*/
printf (" aliased to\n");
printf (" ");
PrintPacket (ip);
printf ("\n");
}
/*
* Put packet back for processing.
*/
wrote = sendto (fd,
buf,
bytes,
0,
(struct sockaddr*) &addr,
sizeof addr);
if (wrote != bytes) {
if (errno == EMSGSIZE) {
if (direction == OUTPUT &&
mip->ifMTU != -1)
SendNeedFragIcmp (icmpSock,
(struct ip*) buf,
mip->ifMTU - mip->aliasOverhead);
}
else if (errno == EACCES && logIpfwDenied) {
sprintf (msgBuf, "failed to write packet back");
Warn (msgBuf);
}
}
}
static void HandleRoutingInfo (int fd)
{
int bytes;
struct if_msghdr ifMsg;
/*
* Get packet from socket.
*/
bytes = read (fd, &ifMsg, sizeof ifMsg);
if (bytes == -1) {
Warn ("read from routing socket failed");
return;
}
if (ifMsg.ifm_version != RTM_VERSION) {
Warn ("unexpected packet read from routing socket");
return;
}
if (verbose)
printf ("Routing message %#x received.\n", ifMsg.ifm_type);
if ((ifMsg.ifm_type == RTM_NEWADDR || ifMsg.ifm_type == RTM_IFINFO)) {
LIST_FOREACH(mip, &root, list) {
mla = mip->la;
if (ifMsg.ifm_index == mip->ifIndex) {
if (verbose)
printf("Interface address/MTU has probably changed.\n");
mip->assignAliasAddr = 1;
}
}
}
}
static void PrintPacket (struct ip* ip)
{
printf ("%s", FormatPacket (ip));
}
static void SyslogPacket (struct ip* ip, int priority, const char *label)
{
syslog (priority, "%s %s", label, FormatPacket (ip));
}
static char* FormatPacket (struct ip* ip)
{
static char buf[256];
struct tcphdr* tcphdr;
struct udphdr* udphdr;
struct icmp* icmphdr;
char src[20];
char dst[20];
strcpy (src, inet_ntoa (ip->ip_src));
strcpy (dst, inet_ntoa (ip->ip_dst));
switch (ip->ip_p) {
case IPPROTO_TCP:
tcphdr = (struct tcphdr*) ((char*) ip + (ip->ip_hl << 2));
sprintf (buf, "[TCP] %s:%d -> %s:%d",
src,
ntohs (tcphdr->th_sport),
dst,
ntohs (tcphdr->th_dport));
break;
case IPPROTO_UDP:
udphdr = (struct udphdr*) ((char*) ip + (ip->ip_hl << 2));
sprintf (buf, "[UDP] %s:%d -> %s:%d",
src,
ntohs (udphdr->uh_sport),
dst,
ntohs (udphdr->uh_dport));
break;
case IPPROTO_ICMP:
icmphdr = (struct icmp*) ((char*) ip + (ip->ip_hl << 2));
sprintf (buf, "[ICMP] %s -> %s %u(%u)",
src,
dst,
icmphdr->icmp_type,
icmphdr->icmp_code);
break;
default:
sprintf (buf, "[%d] %s -> %s ", ip->ip_p, src, dst);
break;
}
return buf;
}
static int
SetAliasAddressFromIfName(const char *ifn)
{
size_t needed;
int mib[6];
char *buf, *lim, *next;
struct if_msghdr *ifm;
struct ifa_msghdr *ifam;
struct sockaddr_dl *sdl;
struct sockaddr_in *sin;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET; /* Only IP addresses please */
mib[4] = NET_RT_IFLIST;
mib[5] = 0; /* ifIndex??? */
/*
* Get interface data.
*/
if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1)
err(1, "iflist-sysctl-estimate");
if ((buf = malloc(needed)) == NULL)
errx(1, "malloc failed");
if (sysctl(mib, 6, buf, &needed, NULL, 0) == -1 && errno != ENOMEM)
err(1, "iflist-sysctl-get");
lim = buf + needed;
/*
* Loop through interfaces until one with
* given name is found. This is done to
* find correct interface index for routing
* message processing.
*/
mip->ifIndex = 0;
next = buf;
while (next < lim) {
ifm = (struct if_msghdr *)next;
next += ifm->ifm_msglen;
if (ifm->ifm_version != RTM_VERSION) {
if (verbose)
warnx("routing message version %d "
"not understood", ifm->ifm_version);
continue;
}
if (ifm->ifm_type == RTM_IFINFO) {
sdl = (struct sockaddr_dl *)(ifm + 1);
if (strlen(ifn) == sdl->sdl_nlen &&
strncmp(ifn, sdl->sdl_data, sdl->sdl_nlen) == 0) {
mip->ifIndex = ifm->ifm_index;
mip->ifMTU = ifm->ifm_data.ifi_mtu;
break;
}
}
}
if (!mip->ifIndex)
errx(1, "unknown interface name %s", ifn);
/*
* Get interface address.
*/
sin = NULL;
while (next < lim) {
ifam = (struct ifa_msghdr *)next;
next += ifam->ifam_msglen;
if (ifam->ifam_version != RTM_VERSION) {
if (verbose)
warnx("routing message version %d "
"not understood", ifam->ifam_version);
continue;
}
if (ifam->ifam_type != RTM_NEWADDR)
break;
if (ifam->ifam_addrs & RTA_IFA) {
int i;
char *cp = (char *)(ifam + 1);
for (i = 1; i < RTA_IFA; i <<= 1)
if (ifam->ifam_addrs & i)
cp += SA_SIZE((struct sockaddr *)cp);
if (((struct sockaddr *)cp)->sa_family == AF_INET) {
sin = (struct sockaddr_in *)cp;
break;
}
}
}
if (sin == NULL) {
warnx("%s: cannot get interface address", ifn);
free(buf);
return EAGAIN;
}
LibAliasSetAddress(mla, sin->sin_addr);
syslog(LOG_INFO, "Aliasing to %s, mtu %d bytes",
inet_ntoa(sin->sin_addr), mip->ifMTU);
free(buf);
return 0;
}
void Quit (const char* msg)
{
Warn (msg);
exit (1);
}
void Warn (const char* msg)
{
if (background)
syslog (LOG_ALERT, "%s (%m)", msg);
else
warn ("%s", msg);
}
static void RefreshAddr (int sig __unused)
{
LibAliasRefreshModules();
if (mip != NULL && mip->ifName != NULL)
mip->assignAliasAddr = 1;
}
static void InitiateShutdown (int sig __unused)
{
/*
* Start timer to allow kernel gracefully
* shutdown existing connections when system
* is shut down.
*/
siginterrupt(SIGALRM, 1);
signal (SIGALRM, Shutdown);
ualarm(exitDelay*1000, 1000);
}
static void Shutdown (int sig __unused)
{
running = 0;
}
/*
* Different options recognized by this program.
*/
enum Option {
LibAliasOption,
Instance,
Verbose,
InPort,
OutPort,
Port,
GlobalPort,
AliasAddress,
TargetAddress,
InterfaceName,
RedirectPort,
RedirectProto,
RedirectAddress,
ConfigFile,
DynamicMode,
ProxyRule,
LogDenied,
LogFacility,
PunchFW,
SkinnyPort,
LogIpfwDenied,
PidFile,
ExitDelay
};
enum Param {
YesNo,
Numeric,
String,
None,
Address,
Service
};
/*
* Option information structure (used by ParseOption).
*/
struct OptionInfo {
enum Option type;
int packetAliasOpt;
enum Param parm;
const char* parmDescription;
const char* description;
const char* name;
const char* shortName;
};
/*
* Table of known options.
*/
static struct OptionInfo optionTable[] = {
{ LibAliasOption,
PKT_ALIAS_UNREGISTERED_ONLY,
YesNo,
"[yes|no]",
"alias only unregistered addresses",
"unregistered_only",
"u" },
{ LibAliasOption,
PKT_ALIAS_LOG,
YesNo,
"[yes|no]",
"enable logging",
"log",
"l" },
{ LibAliasOption,
PKT_ALIAS_PROXY_ONLY,
YesNo,
"[yes|no]",
"proxy only",
"proxy_only",
NULL },
{ LibAliasOption,
PKT_ALIAS_REVERSE,
YesNo,
"[yes|no]",
"operate in reverse mode",
"reverse",
NULL },
{ LibAliasOption,
PKT_ALIAS_DENY_INCOMING,
YesNo,
"[yes|no]",
"allow incoming connections",
"deny_incoming",
"d" },
{ LibAliasOption,
PKT_ALIAS_USE_SOCKETS,
YesNo,
"[yes|no]",
"use sockets to inhibit port conflict",
"use_sockets",
"s" },
{ LibAliasOption,
PKT_ALIAS_SAME_PORTS,
YesNo,
"[yes|no]",
"try to keep original port numbers for connections",
"same_ports",
"m" },
{ Verbose,
0,
YesNo,
"[yes|no]",
"verbose mode, dump packet information",
"verbose",
"v" },
{ DynamicMode,
0,
YesNo,
"[yes|no]",
"dynamic mode, automatically detect interface address changes",
"dynamic",
NULL },
{ InPort,
0,
Service,
"number|service_name",
"set port for incoming packets",
"in_port",
"i" },
{ OutPort,
0,
Service,
"number|service_name",
"set port for outgoing packets",
"out_port",
"o" },
{ Port,
0,
Service,
"number|service_name",
"set port (defaults to natd/divert)",
"port",
"p" },
{ GlobalPort,
0,
Service,
"number|service_name",
"set globalport",
"globalport",
NULL },
{ AliasAddress,
0,
Address,
"x.x.x.x",
"address to use for aliasing",
"alias_address",
"a" },
{ TargetAddress,
0,
Address,
"x.x.x.x",
"address to use for incoming sessions",
"target_address",
"t" },
{ InterfaceName,
0,
String,
"network_if_name",
"take aliasing address from interface",
"interface",
"n" },
{ ProxyRule,
0,
String,
"[type encode_ip_hdr|encode_tcp_stream] port xxxx server "
"a.b.c.d:yyyy",
"add transparent proxying / destination NAT",
"proxy_rule",
NULL },
{ RedirectPort,
0,
String,
"tcp|udp local_addr:local_port_range[,...] [public_addr:]public_port_range"
" [remote_addr[:remote_port_range]]",
"redirect a port (or ports) for incoming traffic",
"redirect_port",
NULL },
{ RedirectProto,
0,
String,
"proto local_addr [public_addr] [remote_addr]",
"redirect packets of a given proto",
"redirect_proto",
NULL },
{ RedirectAddress,
0,
String,
"local_addr[,...] public_addr",
"define mapping between local and public addresses",
"redirect_address",
NULL },
{ ConfigFile,
0,
String,
"file_name",
"read options from configuration file",
"config",
"f" },
{ LogDenied,
0,
YesNo,
"[yes|no]",
"enable logging of denied incoming packets",
"log_denied",
NULL },
{ LogFacility,
0,
String,
"facility",
"name of syslog facility to use for logging",
"log_facility",
NULL },
{ PunchFW,
0,
String,
"basenumber:count",
"punch holes in the firewall for incoming FTP/IRC DCC connections",
"punch_fw",
NULL },
{ SkinnyPort,
0,
String,
"port",
"set the TCP port for use with the Skinny Station protocol",
"skinny_port",
NULL },
{ LogIpfwDenied,
0,
YesNo,
"[yes|no]",
"log packets converted by natd, but denied by ipfw",
"log_ipfw_denied",
NULL },
{ PidFile,
0,
String,
"file_name",
"store PID in an alternate file",
"pid_file",
"P" },
{ Instance,
0,
String,
"instance name",
"name of aliasing engine instance",
"instance",
NULL },
{ ExitDelay,
0,
Numeric,
"ms",
"delay in ms before daemon exit after signal",
"exit_delay",
NULL },
};
static void ParseOption (const char* option, const char* parms)
{
int i;
struct OptionInfo* info;
int yesNoValue;
int aliasValue;
int numValue;
u_short uNumValue;
const char* strValue;
struct in_addr addrValue;
int max;
char* end;
const CODE* fac_record = NULL;
/*
* Find option from table.
*/
max = sizeof (optionTable) / sizeof (struct OptionInfo);
for (i = 0, info = optionTable; i < max; i++, info++) {
if (!strcmp (info->name, option))
break;
if (info->shortName)
if (!strcmp (info->shortName, option))
break;
}
if (i >= max) {
warnx ("unknown option %s", option);
Usage ();
}
uNumValue = 0;
yesNoValue = 0;
numValue = 0;
strValue = NULL;
/*
* Check parameters.
*/
switch (info->parm) {
case YesNo:
if (!parms)
parms = "yes";
if (!strcmp (parms, "yes"))
yesNoValue = 1;
else
if (!strcmp (parms, "no"))
yesNoValue = 0;
else
errx (1, "%s needs yes/no parameter", option);
break;
case Service:
if (!parms)
errx (1, "%s needs service name or "
"port number parameter",
option);
uNumValue = StrToPort (parms, "divert");
break;
case Numeric:
if (parms)
numValue = strtol (parms, &end, 10);
else
end = NULL;
if (end == parms)
errx (1, "%s needs numeric parameter", option);
break;
case String:
strValue = parms;
if (!strValue)
errx (1, "%s needs parameter", option);
break;
case None:
if (parms)
errx (1, "%s does not take parameters", option);
break;
case Address:
if (!parms)
errx (1, "%s needs address/host parameter", option);
StrToAddr (parms, &addrValue);
break;
}
switch (info->type) {
case LibAliasOption:
aliasValue = yesNoValue ? info->packetAliasOpt : 0;
LibAliasSetMode (mla, aliasValue, info->packetAliasOpt);
break;
case Verbose:
verbose = yesNoValue;
break;
case DynamicMode:
dynamicMode = yesNoValue;
break;
case InPort:
mip->inPort = uNumValue;
break;
case OutPort:
mip->outPort = uNumValue;
break;
case Port:
mip->inOutPort = uNumValue;
break;
case GlobalPort:
globalPort = uNumValue;
break;
case AliasAddress:
memcpy (&mip->aliasAddr, &addrValue, sizeof (struct in_addr));
break;
case TargetAddress:
LibAliasSetTarget(mla, addrValue);
break;
case RedirectPort:
SetupPortRedirect (strValue);
break;
case RedirectProto:
SetupProtoRedirect(strValue);
break;
case RedirectAddress:
SetupAddressRedirect (strValue);
break;
case ProxyRule:
LibAliasProxyRule (mla, strValue);
break;
case InterfaceName:
if (mip->ifName)
free (mip->ifName);
mip->ifName = strdup (strValue);
break;
case ConfigFile:
ReadConfigFile (strValue);
break;
case LogDenied:
mip->logDropped = yesNoValue;
break;
case LogFacility:
fac_record = facilitynames;
while (fac_record->c_name != NULL) {
if (!strcmp (fac_record->c_name, strValue)) {
logFacility = fac_record->c_val;
break;
}
else
fac_record++;
}
if(fac_record->c_name == NULL)
errx(1, "Unknown log facility name: %s", strValue);
break;
case PunchFW:
SetupPunchFW(strValue);
break;
case SkinnyPort:
SetupSkinnyPort(strValue);
break;
case LogIpfwDenied:
logIpfwDenied = yesNoValue;
break;
case PidFile:
pidName = strdup (strValue);
break;
case Instance:
NewInstance(strValue);
break;
case ExitDelay:
if (numValue < 0 || numValue > MAX_EXIT_DELAY)
errx(1, "Incorrect exit delay: %d", numValue);
exitDelay = numValue;
break;
}
}
void ReadConfigFile (const char* fileName)
{
FILE* file;
char *buf;
size_t len;
char *ptr, *p;
char* option;
file = fopen (fileName, "r");
if (!file)
err(1, "cannot open config file %s", fileName);
while ((buf = fgetln(file, &len)) != NULL) {
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
else
errx(1, "config file format error: "
"last line should end with newline");
/*
* Check for comments, strip off trailing spaces.
*/
if ((ptr = strchr(buf, '#')))
*ptr = '\0';
for (ptr = buf; isspace(*ptr); ++ptr)
continue;
if (*ptr == '\0')
continue;
for (p = strchr(buf, '\0'); isspace(*--p);)
continue;
*++p = '\0';
/*
* Extract option name.
*/
option = ptr;
while (*ptr && !isspace (*ptr))
++ptr;
if (*ptr != '\0') {
*ptr = '\0';
++ptr;
}
/*
* Skip white space between name and parms.
*/
while (*ptr && isspace (*ptr))
++ptr;
ParseOption (option, *ptr ? ptr : NULL);
}
fclose (file);
}
static void Usage(void)
{
int i;
int max;
struct OptionInfo* info;
fprintf (stderr, "Recognized options:\n\n");
max = sizeof (optionTable) / sizeof (struct OptionInfo);
for (i = 0, info = optionTable; i < max; i++, info++) {
fprintf (stderr, "-%-20s %s\n", info->name,
info->parmDescription);
if (info->shortName)
fprintf (stderr, "-%-20s %s\n", info->shortName,
info->parmDescription);
fprintf (stderr, " %s\n\n", info->description);
}
exit (1);
}
void SetupPortRedirect (const char* parms)
{
char *buf;
char* ptr;
char* serverPool;
struct in_addr localAddr;
struct in_addr publicAddr;
struct in_addr remoteAddr;
port_range portRange;
u_short localPort = 0;
u_short publicPort = 0;
u_short remotePort = 0;
u_short numLocalPorts = 0;
u_short numPublicPorts = 0;
u_short numRemotePorts = 0;
int proto;
char* protoName;
char* separator;
int i;
struct alias_link *aliaslink = NULL;
buf = strdup (parms);
if (!buf)
errx (1, "redirect_port: strdup() failed");
/*
* Extract protocol.
*/
protoName = strtok (buf, " \t");
if (!protoName)
errx (1, "redirect_port: missing protocol");
proto = StrToProto (protoName);
/*
* Extract local address.
*/
ptr = strtok (NULL, " \t");
if (!ptr)
errx (1, "redirect_port: missing local address");
separator = strchr(ptr, ',');
if (separator) { /* LSNAT redirection syntax. */
localAddr.s_addr = INADDR_NONE;
localPort = ~0;
numLocalPorts = 1;
serverPool = ptr;
} else {
if ( StrToAddrAndPortRange (ptr, &localAddr, protoName, &portRange) != 0 )
errx (1, "redirect_port: invalid local port range");
localPort = GETLOPORT(portRange);
numLocalPorts = GETNUMPORTS(portRange);
serverPool = NULL;
}
/*
* Extract public port and optionally address.
*/
ptr = strtok (NULL, " \t");
if (!ptr)
errx (1, "redirect_port: missing public port");
separator = strchr (ptr, ':');
if (separator) {
if (StrToAddrAndPortRange (ptr, &publicAddr, protoName, &portRange) != 0 )
errx (1, "redirect_port: invalid public port range");
}
else {
publicAddr.s_addr = INADDR_ANY;
if (StrToPortRange (ptr, protoName, &portRange) != 0)
errx (1, "redirect_port: invalid public port range");
}
publicPort = GETLOPORT(portRange);
numPublicPorts = GETNUMPORTS(portRange);
/*
* Extract remote address and optionally port.
*/
ptr = strtok (NULL, " \t");
if (ptr) {
separator = strchr (ptr, ':');
if (separator) {
if (StrToAddrAndPortRange (ptr, &remoteAddr, protoName, &portRange) != 0)
errx (1, "redirect_port: invalid remote port range");
} else {
SETLOPORT(portRange, 0);
SETNUMPORTS(portRange, 1);
StrToAddr (ptr, &remoteAddr);
}
}
else {
SETLOPORT(portRange, 0);
SETNUMPORTS(portRange, 1);
remoteAddr.s_addr = INADDR_ANY;
}
remotePort = GETLOPORT(portRange);
numRemotePorts = GETNUMPORTS(portRange);
/*
* Make sure port ranges match up, then add the redirect ports.
*/
if (numLocalPorts != numPublicPorts)
errx (1, "redirect_port: port ranges must be equal in size");
/* Remote port range is allowed to be '0' which means all ports. */
if (numRemotePorts != numLocalPorts && (numRemotePorts != 1 || remotePort != 0))
errx (1, "redirect_port: remote port must be 0 or equal to local port range in size");
for (i = 0 ; i < numPublicPorts ; ++i) {
/* If remotePort is all ports, set it to 0. */
u_short remotePortCopy = remotePort + i;
if (numRemotePorts == 1 && remotePort == 0)
remotePortCopy = 0;
aliaslink = LibAliasRedirectPort (mla, localAddr,
htons(localPort + i),
remoteAddr,
htons(remotePortCopy),
publicAddr,
htons(publicPort + i),
proto);
}
/*
* Setup LSNAT server pool.
*/
if (serverPool != NULL && aliaslink != NULL) {
ptr = strtok(serverPool, ",");
while (ptr != NULL) {
if (StrToAddrAndPortRange(ptr, &localAddr, protoName, &portRange) != 0)
errx(1, "redirect_port: invalid local port range");
localPort = GETLOPORT(portRange);
if (GETNUMPORTS(portRange) != 1)
errx(1, "redirect_port: local port must be single in this context");
LibAliasAddServer(mla, aliaslink, localAddr, htons(localPort));
ptr = strtok(NULL, ",");
}
}
free (buf);
}
void
SetupProtoRedirect(const char* parms)
{
char *buf;
char* ptr;
struct in_addr localAddr;
struct in_addr publicAddr;
struct in_addr remoteAddr;
int proto;
char* protoName;
struct protoent *protoent;
buf = strdup (parms);
if (!buf)
errx (1, "redirect_port: strdup() failed");
/*
* Extract protocol.
*/
protoName = strtok(buf, " \t");
if (!protoName)
errx(1, "redirect_proto: missing protocol");
protoent = getprotobyname(protoName);
if (protoent == NULL)
errx(1, "redirect_proto: unknown protocol %s", protoName);
else
proto = protoent->p_proto;
/*
* Extract local address.
*/
ptr = strtok(NULL, " \t");
if (!ptr)
errx(1, "redirect_proto: missing local address");
else
StrToAddr(ptr, &localAddr);
/*
* Extract optional public address.
*/
ptr = strtok(NULL, " \t");
if (ptr)
StrToAddr(ptr, &publicAddr);
else
publicAddr.s_addr = INADDR_ANY;
/*
* Extract optional remote address.
*/
ptr = strtok(NULL, " \t");
if (ptr)
StrToAddr(ptr, &remoteAddr);
else
remoteAddr.s_addr = INADDR_ANY;
/*
* Create aliasing link.
*/
(void)LibAliasRedirectProto(mla, localAddr, remoteAddr, publicAddr,
proto);
free (buf);
}
void SetupAddressRedirect (const char* parms)
{
char *buf;
char* ptr;
char* separator;
struct in_addr localAddr;
struct in_addr publicAddr;
char* serverPool;
struct alias_link *aliaslink;
buf = strdup (parms);
if (!buf)
errx (1, "redirect_port: strdup() failed");
/*
* Extract local address.
*/
ptr = strtok (buf, " \t");
if (!ptr)
errx (1, "redirect_address: missing local address");
separator = strchr(ptr, ',');
if (separator) { /* LSNAT redirection syntax. */
localAddr.s_addr = INADDR_NONE;
serverPool = ptr;
} else {
StrToAddr (ptr, &localAddr);
serverPool = NULL;
}
/*
* Extract public address.
*/
ptr = strtok (NULL, " \t");
if (!ptr)
errx (1, "redirect_address: missing public address");
StrToAddr (ptr, &publicAddr);
aliaslink = LibAliasRedirectAddr(mla, localAddr, publicAddr);
/*
* Setup LSNAT server pool.
*/
if (serverPool != NULL && aliaslink != NULL) {
ptr = strtok(serverPool, ",");
while (ptr != NULL) {
StrToAddr(ptr, &localAddr);
LibAliasAddServer(mla, aliaslink, localAddr, htons(~0));
ptr = strtok(NULL, ",");
}
}
free (buf);
}
void StrToAddr (const char* str, struct in_addr* addr)
{
struct hostent* hp;
if (inet_aton (str, addr))
return;
hp = gethostbyname (str);
if (!hp)
errx (1, "unknown host %s", str);
memcpy (addr, hp->h_addr, sizeof (struct in_addr));
}
u_short StrToPort (const char* str, const char* proto)
{
u_short port;
struct servent* sp;
char* end;
port = strtol (str, &end, 10);
if (end != str)
return htons (port);
sp = getservbyname (str, proto);
if (!sp)
errx (1, "%s/%s: unknown service", str, proto);
return sp->s_port;
}
int StrToPortRange (const char* str, const char* proto, port_range *portRange)
{
const char* sep;
struct servent* sp;
char* end;
u_short loPort;
u_short hiPort;
/* First see if this is a service, return corresponding port if so. */
sp = getservbyname (str,proto);
if (sp) {
SETLOPORT(*portRange, ntohs(sp->s_port));
SETNUMPORTS(*portRange, 1);
return 0;
}
/* Not a service, see if it's a single port or port range. */
sep = strchr (str, '-');
if (sep == NULL) {
SETLOPORT(*portRange, strtol(str, &end, 10));
if (end != str) {
/* Single port. */
SETNUMPORTS(*portRange, 1);
return 0;
}
/* Error in port range field. */
errx (1, "%s/%s: unknown service", str, proto);
}
/* Port range, get the values and sanity check. */
sscanf (str, "%hu-%hu", &loPort, &hiPort);
SETLOPORT(*portRange, loPort);
SETNUMPORTS(*portRange, 0); /* Error by default */
if (loPort <= hiPort)
SETNUMPORTS(*portRange, hiPort - loPort + 1);
if (GETNUMPORTS(*portRange) == 0)
errx (1, "invalid port range %s", str);
return 0;
}
static int
StrToProto (const char* str)
{
if (!strcmp (str, "tcp"))
return IPPROTO_TCP;
if (!strcmp (str, "udp"))
return IPPROTO_UDP;
errx (1, "unknown protocol %s. Expected tcp or udp", str);
}
static int
StrToAddrAndPortRange (char* str, struct in_addr* addr, char* proto, port_range *portRange)
{
char* ptr;
ptr = strchr (str, ':');
if (!ptr)
errx (1, "%s is missing port number", str);
*ptr = '\0';
++ptr;
StrToAddr (str, addr);
return StrToPortRange (ptr, proto, portRange);
}
static void
SetupPunchFW(const char *strValue)
{
unsigned int base, num;
if (sscanf(strValue, "%u:%u", &base, &num) != 2)
errx(1, "punch_fw: basenumber:count parameter required");
if (CheckIpfwRulenum(base + num - 1) == -1)
errx(1, "punch_fw: basenumber:count parameter should fit "
"the maximum allowed rule numbers");
LibAliasSetFWBase(mla, base, num);
(void)LibAliasSetMode(mla, PKT_ALIAS_PUNCH_FW, PKT_ALIAS_PUNCH_FW);
}
static void
SetupSkinnyPort(const char *strValue)
{
unsigned int port;
if (sscanf(strValue, "%u", &port) != 1)
errx(1, "skinny_port: port parameter required");
LibAliasSetSkinnyPort(mla, port);
}
static void
NewInstance(const char *name)
{
struct instance *ip;
LIST_FOREACH(ip, &root, list) {
if (!strcmp(ip->name, name)) {
mla = ip->la;
mip = ip;
return;
}
}
ninstance++;
ip = calloc(1, sizeof(*ip));
ip->name = strdup(name);
ip->la = LibAliasInit (ip->la);
ip->assignAliasAddr = 0;
ip->ifName = NULL;
ip->logDropped = 0;
ip->inPort = 0;
ip->outPort = 0;
ip->inOutPort = 0;
ip->aliasAddr.s_addr = INADDR_NONE;
ip->ifMTU = -1;
ip->aliasOverhead = 12;
LIST_INSERT_HEAD(&root, ip, list);
mla = ip->la;
mip = ip;
}
static int
CheckIpfwRulenum(unsigned int rnum)
{
unsigned int default_rule;
size_t len = sizeof(default_rule);
if (sysctlbyname("net.inet.ip.fw.default_rule", &default_rule, &len,
NULL, 0) == -1) {
warn("Failed to get the default ipfw rule number, using "
"default historical value 65535. The reason was");
default_rule = 65535;
}
if (rnum >= default_rule) {
return -1;
}
return 0;
}
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