#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
+#include <sys/socket.h>
#include <time.h>
#include <unistd.h>
// Details of actualized connections.
struct Remote {
- struct SockAddr uaddr;
+ struct SockAddr uaddr; // The remote IP address
+ struct SockAddr laddr; // The local IP address
struct Allowed *spec; // Rule being instantiated
struct timeval rec_when; // Last received packet time, in seconds
};
typedef struct _PacketItem {
QueueItem base;
int fd;
- struct SockAddr src;
+ struct SockAddr src; // the remote IP for this packet
+ struct SockAddr dst; // the local IP for this packet
ssize_t len;
unsigned char buffer[ BUFSIZE ];
} PacketItem;
// Flag to signal the UDP socket as being ipv6 or not (forced ipv4)
static int udp6 = 1;
+// The given UDP source address, if any
+static struct {
+ int family;
+ unsigned char address[16];
+} udp_source;
+
// Flag to indicate tpg transport patch = avoid UDP payload of 1470
// bytes by adding 2 tag-along bytes
static int tpg_quirk = 0;
return 0;
}
+//** IP address parsing utility for UDP source address
+// Return 0 if ok and 1 otherwise
+// Formats: <ipv4-address> or <ipv6-address>
+// The ipv4 address should be a multicast address in ranges
+// 224.0.0.0/22, 232.0.0.0/7, 234.0.0.0/8 or 239.0.0.0/8
+// though it's not checked here.
+static int parse_udp_source(char *arg) {
+ if ( inet_pton( AF_INET6, arg, udp_source.address ) ) {
+ // An ipv6 address is given.
+ if ( udp6 ) {
+ udp_source.family = AF_INET6;
+ return 0;
+ }
+ return 1;
+ }
+ if ( ! inet_pton( AF_INET, arg, udp_source.address ) ) {
+ return 1;
+ }
+
+ // An ipv4 address is given.
+ if ( udp6 ) {
+ // Translate into ipv6-encoded ipv4
+ memmove( udp_source.address + 12, udp_source.address, 4 );
+ memset( udp_source.address, 0, 10 );
+ memset( udp_source.address + 10, -1, 2 );
+ udp_source.family = AF_INET6;
+ } else {
+ udp_source.family = AF_INET;
+ }
+ return 0;
+}
+
// Utility that sets upt the multicast socket, which is used for
// receiving multicast packets.
static void setup_mcast() {
// A packet buffer
unsigned char output[ BUFSIZE ];
if ( n < 12 ) {
- VERBOSE2OUT( "SEND %d bytes to %s\n", n, inet_stoa( &r->uaddr ) );
+ VERBOSE2OUT( "SENDing %d bytes to %s\n", n, inet_stoa( &r->uaddr ) );
} else {
- VERBOSE2OUT( "SEND %d bytes %s -> %s to %s\n", n,
+ VERBOSE2OUT( "SENDing %d bytes %s -> %s from %s to %s\n", n,
inet_mtoa( buf+6 ), inet_mtoa( buf ),
+ inet_stoa( &r->laddr ),
inet_stoa( &r->uaddr ) );
}
memcpy( output, buf, n ); // Use the private buffer for delivery
} else if ( r->spec->psk.keyfile ) {
encrypt( output, n, &r->spec->psk );
}
- struct sockaddr *sock = &r->uaddr.in;
+ // Reserve for packet addressing
+ struct in_pktinfo pkt4info = {
+ .ipi_ifindex = 0, /* Interface index */
+ .ipi_spec_dst.s_addr = 0, /* Local address */
+ .ipi_addr.s_addr = 0, /* Header Destination address */
+ };
+ struct in6_pktinfo pkt6info = {
+ .ipi6_addr.s6_addr32 = { 0, 0, 0, 0 },
+ .ipi6_ifindex = 0,
+ };
+ void *pktinfo = 0;
+ int pktinfosize = 0;
+ struct sockaddr_in *sock4 = &r->uaddr.in4;
+ struct sockaddr_in6 *sock6 = &r->uaddr.in6;
+ void *sock;
size_t size;
- if ( sock->sa_family == AF_INET6 ) {
+ int flags = 0;
+ if ( udp6 ) {
// Note that the size of +struct sockaddr_in6+ is actually
// larger than the size of +struct sockaddr+ (due to the
// addition of the +sin6_flowinfo+ field). It results in the
// following cuteness for passing arguments to +sendto+.
+ sock = sock6;
size = sizeof( struct sockaddr_in6 );
- VERBOSE2OUT( "IPv6 UDP %d %s\n",
- udp_fd, inet_stoa( (struct SockAddr*) sock ) );
+ VERBOSE2OUT( "IPv6 UDP %d %s %s\n", udp_fd,
+ inet_stoa( &r->laddr ),
+ inet_stoa( &r->uaddr ) );
+ switch ( r->laddr.in.sa_family ) {
+ case AF_INET6:
+ memcpy( &pkt6info.ipi6_addr, &sock6->sin6_addr, 16 );
+ pktinfo = &pkt6info;
+ pktinfosize = sizeof( pkt6info );
+ flags = IPV6_PKTINFO;
+ break;
+ case AF_INET:
+ memcpy( &pkt4info.ipi_spec_dst, &sock4->sin_addr, 4 );
+ pktinfo = &pkt4info;
+ pktinfosize = sizeof( pkt4info );
+ flags = IP_PKTINFO;
+ break;
+ }
} else {
+ sock = sock4;
size = sizeof( struct sockaddr_in );
- VERBOSE2OUT( "IPv4 UDP %d %s\n",
- udp_fd, inet_stoa( (struct SockAddr*) sock ) );
- }
- VERBOSE2OUT( "SEND %d bytes to %s [%s -> %s]\n",
- n, inet_stoa( (struct SockAddr*) sock ),
+ VERBOSE2OUT( "IPv4 UDP %d %s %s\n", udp_fd,
+ inet_stoa( &r->laddr ),
+ inet_stoa( &r->uaddr ) );
+ memcpy( &pkt4info.ipi_spec_dst, &sock4->sin_addr, 4 );
+ pktinfo = &pkt4info;
+ pktinfosize = sizeof( pkt4info );
+ flags = IP_PKTINFO;
+ }
+ VERBOSE2OUT( "SEND %d bytes from %s to %s [%s -> %s]\n",
+ n,
+ inet_stoa( &r->laddr ),
+ inet_stoa( &r->uaddr ),
( n < 12 )? "" : inet_mtoa( buf+6 ),
( n < 12 )? "" : inet_mtoa( buf )
);
- // IS sendto thread safe??
- if ( sendto( udp_fd, output, n, 0, sock, size ) < n ) {
+ // IS sendmsg thread safe??
+ struct iovec data[1] = {{ output, n }};
+ struct msghdr msg = {
+ .msg_name = sock,
+ .msg_namelen = size,
+ .msg_iov = data,
+ .msg_iovlen = 1,
+ .msg_control = pktinfo,
+ .msg_controllen = pktinfosize,
+ .msg_flags = 0 // unused
+ };
+ if ( sendmsg( udp_fd, &msg, flags ) < n ) {
perror( "Writing socket" );
// Invalidate remote temporarily instead? But if it's an
// "uplink" it should be retried eventually...
}
// Check packet and deliver out
-static void route_packet(unsigned char *buf,int len,struct SockAddr *src) {
+static void route_packet(PacketItem *pi) {
+ unsigned char *buf = pi->buffer;
+ int len = pi->len;
+ struct SockAddr *src = &pi->src;
struct Interface *x = input_check( buf, len, src );
if ( x == 0 ) {
return; // not a nice packet
Interface_DEL( y ); // Need to see this interface again
return;
}
- VERBOSE2OUT( "RECV route %s -> %s to %s\n",
+ // Set the local address for the remote
+ memcpy( &x->remote->laddr, &pi->dst, sizeof( pi->dst ) );
+ VERBOSE2OUT( "RECV route %s -> %s using %s\n",
inet_mtoa( buf+6 ), inet_mtoa( buf ),
- inet_stoa( &y->remote->uaddr ) );
+ inet_stoa( &x->remote->laddr ) );
write_remote( buf, len, y->remote );
return;
}
for ( ;; ) {
PacketItem *todo = (PacketItem *) Queue_getItem( &todolist.full );
if ( todo->fd == mcast.fd ) {
- // Patch multicast address as source for multicast packet
- route_packet( todo->buffer, todo->len, &mcast.sock );
+ // Patch in the multicast address as source for multicast packet
+ memcpy( &todo->src, &mcast.sock, sizeof( todo->src ) );
+ route_packet( todo );
} else {
if ( udp6 ) {
unmap_if_mapped( &todo->src );
+ unmap_if_mapped( &todo->dst );
}
- route_packet( todo->buffer, todo->len, &todo->src );
+ route_packet( todo );
}
+ memset( &todo->src, 0, sizeof( struct SockAddr ) );
+ memset( &todo->dst, 0, sizeof( struct SockAddr ) );
Queue_addItem( &todolist.free, (QueueItem*) todo );
}
return 0;
}
}
+// Reads a UDP packet on the given file descriptor and captures the
+// source and destination addresses of the UDP message.
+inline static ssize_t recvpacket(int fd,PacketItem *p) {
+ char data[100]; // Data area for "pktinfo"
+ struct iovec buffer[1] = {{ p->buffer, BUFSIZE }};
+ struct msghdr msg = {
+ .msg_name = &p->src.in,
+ .msg_namelen = udp6? sizeof( p->src.in6 ) : sizeof( p->src.in4 ),
+ .msg_iov = buffer,
+ .msg_iovlen = 1,
+ .msg_control = data,
+ .msg_controllen = sizeof( data ),
+ .msg_flags = 0 // Return value
+ };
+ p->len = recvmsg( fd, &msg, udp6? 0 : IP_PKTINFO );
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR( &msg );
+ if ( cmsg ) {
+ if ( udp6 ) {
+ struct in6_pktinfo *pinf = (struct in6_pktinfo*) CMSG_DATA( cmsg );
+ p->dst.in6.sin6_family = AF_INET6;
+ memcpy( &p->dst.in6.sin6_addr, &pinf->ipi6_addr, 16 );
+ VERBOSE2OUT( "DEST= udp6 %d %s\n",
+ pinf->ipi6_ifindex, inet_stoa( &p->dst ) );
+ } else {
+ struct in_pktinfo *pinf = (struct in_pktinfo*) CMSG_DATA( cmsg );
+ p->dst.in4.sin_family = AF_INET;
+ p->dst.in4.sin_addr = pinf->ipi_addr;
+ VERBOSE2OUT( "DEST= %d %s\n",
+ pinf->ipi_ifindex, inet_stoa( &p->dst ) );
+ }
+ }
+ return p->len;
+}
+
+
+
// Read a full UDP packet into the given buffer, associate with a
// connection, or create a new connection, the decrypt the as
// specified, and capture the sender MAC address. The connection table
int fd = ((ReaderData *) data)->fd;
while ( 1 ) {
PacketItem *todo = (PacketItem *) Queue_getItem( &todolist.free );
- socklen_t addrlen =
- udp6? sizeof( todo->src.in6 ) : sizeof( todo->src.in4 );
- memset( &todo->src, 0, sizeof( todo->src ) );
todo->fd = fd;
- todo->len = recvfrom(
- fd, todo->buffer, BUFSIZE, 0, &todo->src.in, &addrlen );
- if ( todo->len == -1) {
+ VERBOSE3OUT( "Reading packet on %d\n", fd );
+ ssize_t len = recvpacket( fd, todo );
+ if ( len == -1) {
perror( "Receiving UDP" );
exit( 1 );
}
#ifdef GPROF
- if ( todo->len == 17 &&
+ if ( len == 17 &&
memcmp( todo->buffer, "STOPSTOPSTOPSTOP", 16 ) == 0 ) {
exit( 0 );
}
fprintf( stderr, "Packet tunneling over UDP, multiple channels, " );
fprintf( stderr, "version 1.5.3\n" );
fprintf( stderr, "Usage: " );
- fprintf( stderr,
- "%s [-v] [-tpg] [-4] [-B n] [-T n] [-m mcast] [-t tap] port [remote]+ \n",
- progname );
+ fprintf( stderr, "%s [options] port [remote]+ \n", progname );
+ fprintf( stderr, "** options must be given or omitted in order!!\n" );
+ fprintf( stderr, " -v = verbose log, -vv or -vvv for more logs\n" );
+ fprintf( stderr, " -tpg = UDP transport quirk: avoid bad sizes\n" );
+ fprintf( stderr, " -4 = use an ipv4 UDP socket\n" );
+ fprintf( stderr, " -B n = use n buffers (2*threads) by default\n");
+ fprintf( stderr, " -T n = use n delivery threads (5 bu default)\n" );
+ fprintf( stderr, " -m mcast = allow remotes on multicast address\n" );
+ fprintf( stderr, " -t tap = use the nominated tap (or - for stdio)\n" );
+ fprintf( stderr, " -S source = use given source address for UDP\n" );
exit( 1 );
}
i += 2;
ENSUREARGS( 1 );
}
+ // Then optional source address for UDP
+ if ( strncmp( "-S", argv[i], 2 ) == 0 ) {
+ ENSUREARGS( 2 );
+ if ( parse_udp_source( argv[i+1] ) ) {
+ usage();
+ }
+ i += 2;
+ ENSUREARGS( 1 );
+ }
// then: required port
if ( sscanf( argv[i++], "%d", &port ) != 1 ) {
fprintf( stderr, "Bad local port: %s\n", argv[i-1] );
struct sockaddr_in udp_addr = {
.sin_family = AF_INET,
.sin_port = htons( port ),
- .sin_addr.s_addr = htonl(INADDR_ANY),
};
+ if ( udp_source.family == 0 ) {
+ udp_addr.sin_addr.s_addr = htonl( INADDR_ANY );
+ } else {
+ udp_addr.sin_addr.s_addr = *((uint32_t*) udp_source.address);
+ }
if ( bind( udp_fd, (struct sockaddr*) &udp_addr, sizeof(udp_addr))) {
fprintf( stderr, "Error binding socket!\n");
exit(1);
}
VERBOSEOUT( "Using ipv4 UDP at %d\n", udp_fd );
+ int opt = 1;
+ if ( setsockopt( udp_fd, IPPROTO_IP, IP_PKTINFO, &opt, sizeof(opt)) ) {
+ fprintf( stderr, "Error configuring socket!\n");
+ exit(1);
+ }
} else {
// set up ipv6 socket
if ( ( udp_fd = socket( AF_INET6, SOCK_DGRAM, 0 ) ) == 0 ) {
struct sockaddr_in6 udp6_addr = {
.sin6_family = AF_INET6,
.sin6_port = htons( port ),
- .sin6_addr = IN6ADDR_ANY_INIT,
};
+ memcpy( udp6_addr.sin6_addr.s6_addr, udp_source.address, 16 );
if ( bind( udp_fd, (struct sockaddr*) &udp6_addr, sizeof(udp6_addr))) {
fprintf( stderr, "Error binding socket!\n");
exit(1);
}
VERBOSEOUT( "Using ipv6 UDP at %d\n", udp_fd );
+ int opt = 1;
+ if ( setsockopt(
+ udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &opt, sizeof(opt)) ) {
+ fprintf( stderr, "Error configuring socket!\n");
+ exit(1);
+ }
}
// If not using stdio for local traffic, then stdin and stdout are
// closed here, so as to avoid that any other traffic channel gets