*/
#define _GNU_SOURCE
-#include <ws2tcpip.h>
#include <winsock2.h>
+#include <ws2tcpip.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
/**
* IPv4 header.
*/
-struct ip_header
+struct ip_header
{
/**
- * Version (4 bits) + Internet header length (4 bits)
+ * Version (4 bits) + Internet header length (4 bits)
*/
- uint8_t vers_ihl;
+ uint8_t vers_ihl;
/**
* Type of service
*/
- uint8_t tos;
+ uint8_t tos;
/**
* Total length
*/
- uint16_t pkt_len;
+ uint16_t pkt_len;
/**
* Identification
*/
- uint16_t id;
+ uint16_t id;
/**
* Flags (3 bits) + Fragment offset (13 bits)
*/
- uint16_t flags_frag_offset;
+ uint16_t flags_frag_offset;
/**
* Time to live
*/
- uint8_t ttl;
+ uint8_t ttl;
/**
- * Protocol
+ * Protocol
*/
- uint8_t proto;
+ uint8_t proto;
/**
* Header checksum
*/
- uint16_t checksum;
+ uint16_t checksum;
/**
* Source address
*/
- uint32_t src_ip;
+ uint32_t src_ip;
/**
- * Destination address
+ * Destination address
*/
- uint32_t dst_ip;
+ uint32_t dst_ip;
};
/**
* Format of ICMP packet.
*/
-struct icmp_ttl_exceeded_header
+struct icmp_ttl_exceeded_header
{
uint8_t type;
/**
* Port we are listening on (communicated to the server).
- */
+ */
static uint16_t port;
* @param buf where to write the address result
* @return 1 on success
*/
-static int
-inet_pton (int af,
- const char *cp,
+static int
+inet_pton (int af,
+ const char *cp,
struct in_addr *buf)
{
buf->s_addr = inet_addr(cp);
if (buf->s_addr == INADDR_NONE)
{
- fprintf(stderr,
- "Error %d handling address %s",
- WSAGetLastError(),
+ fprintf(stderr,
+ "Error %d handling address %s",
+ WSAGetLastError(),
cp);
return 0;
}
* @param bytes number of bytes in data (must be multiple of 2)
* @return the CRC 16.
*/
-static uint16_t
-calc_checksum(const uint16_t *data,
+static uint16_t
+calc_checksum(const uint16_t *data,
unsigned int bytes)
{
uint32_t sum;
unsigned int i;
sum = 0;
- for (i=0;i<bytes/2;i++)
- sum += data[i];
+ for (i=0;i<bytes/2;i++)
+ sum += data[i];
sum = (sum & 0xffff) + (sum >> 16);
sum = htons(0xffff - sum);
return sum;
const struct in_addr *other)
{
char packet[sizeof(struct ip_header) * 2 +
- sizeof(struct icmp_ttl_exceeded_header) +
+ sizeof(struct icmp_ttl_exceeded_header) +
sizeof(struct udp_header)];
struct ip_header ip_pkt;
struct icmp_ttl_exceeded_header icmp_pkt;
ip_pkt.checksum = 0;
ip_pkt.src_ip = my_ip->s_addr;
ip_pkt.dst_ip = other->s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
sizeof (struct ip_header)));
- memcpy(&packet[off],
- &ip_pkt,
+ memcpy(&packet[off],
+ &ip_pkt,
sizeof(struct ip_header));
off += sizeof(struct ip_header);
icmp_pkt.checksum = 0;
icmp_pkt.unused = 0;
memcpy(&packet[off],
- &icmp_pkt,
+ &icmp_pkt,
sizeof(struct icmp_ttl_exceeded_header));
off += sizeof(struct icmp_ttl_exceeded_header);
ip_pkt.checksum = 0;
ip_pkt.src_ip = other->s_addr;
ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
sizeof (struct ip_header)));
- memcpy(&packet[off],
- &ip_pkt,
+ memcpy(&packet[off],
+ &ip_pkt,
sizeof(struct ip_header));
off += sizeof(struct ip_header);
/* build UDP header */
udp_pkt.src_port = htons(NAT_TRAV_PORT);
- udp_pkt.dst_port = htons(NAT_TRAV_PORT);
+ udp_pkt.dst_port = htons(NAT_TRAV_PORT);
udp_pkt.length = htons (port);
udp_pkt.crc = 0;
- memcpy(&packet[off],
- &udp_pkt,
+ memcpy(&packet[off],
+ &udp_pkt,
sizeof(struct udp_header));
off += sizeof(struct udp_header);
/* no go back to calculate ICMP packet checksum */
icmp_pkt.checksum = htons(calc_checksum((uint16_t*)&packet[off],
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct ip_header) +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct ip_header) +
sizeof (struct udp_header)));
- memcpy (&packet[sizeof (struct ip_header)],
- &icmp_pkt,
+ memcpy (&packet[sizeof (struct ip_header)],
+ &icmp_pkt,
sizeof (struct icmp_ttl_exceeded_header));
-
+
memset (&dst, 0, sizeof (dst));
dst.sin_family = AF_INET;
dst.sin_addr = *other;
struct icmp_ttl_exceeded_header icmp_ttl;
struct icmp_echo_header icmp_echo;
struct sockaddr_in dst;
- char packet[sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
+ char packet[sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
sizeof(struct icmp_echo_header)];
size_t off;
int err;
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons(256);
+ ip_pkt.id = htons(256);
ip_pkt.flags_frag_offset = 0;
ip_pkt.ttl = IPDEFTTL;
ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
+ ip_pkt.checksum = 0;
ip_pkt.src_ip = my_ip->s_addr;
ip_pkt.dst_ip = other->s_addr;
ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
/* icmp reply: time exceeded */
icmp_ttl.type = ICMP_TIME_EXCEEDED;
- icmp_ttl.code = 0;
- icmp_ttl.reserved = 0;
+ icmp_ttl.code = 0;
icmp_ttl.checksum = 0;
+ icmp_ttl.unused = 0;
memcpy (&packet[off],
&icmp_ttl,
sizeof (struct icmp_ttl_exceeded_header));
/* ip header of the presumably 'lost' udp packet */
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
- ip_pkt.pkt_len = (sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
- ip_pkt.id = htons (256);
+ ip_pkt.pkt_len = htons(sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
+ ip_pkt.id = htons (256);
ip_pkt.flags_frag_offset = 0;
ip_pkt.ttl = 1; /* real TTL would be 1 on a time exceeded packet */
ip_pkt.proto = IPPROTO_ICMP;
ip_pkt.dst_ip = dummy.s_addr;
ip_pkt.checksum = 0;
ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
sizeof (struct ip_header));
off += sizeof (struct ip_header);
icmp_echo.type = ICMP_ECHO;
icmp_echo.code = 0;
- icmp_echo.reserved = 0;
+ icmp_echo.reserved = htonl(port);
icmp_echo.checksum = 0;
- icmp_echo.data = htons(port);
- icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
+ icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
sizeof (struct icmp_echo_header)));
memcpy (&packet[off],
- &icmp_echo,
+ &icmp_echo,
sizeof(struct icmp_echo_header));
/* no go back to calculate ICMP packet checksum */
off = sizeof (struct ip_header);
icmp_ttl.checksum = htons(calc_checksum((uint16_t*) &packet[off],
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct ip_header) +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct ip_header) +
sizeof (struct icmp_echo_header)));
memcpy (&packet[off],
&icmp_ttl,
dst.sin_family = AF_INET;
dst.sin_addr = *other;
- err = sendto(rawsock,
+ err = sendto(rawsock,
packet,
sizeof (packet), 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
+ (struct sockaddr*)&dst,
+ sizeof(dst));
- if (err < 0)
+ if (err < 0)
{
fprintf(stderr,
"sendto failed: %s\n", strerror(errno));
}
- else if (sizeof (packet) != (size_t) err)
+ else if (sizeof (packet) != (size_t) err)
{
fprintf(stderr,
"Error: partial send of ICMP message\n");
"Error opening RAW socket: %s\n",
strerror (errno));
return INVALID_SOCKET;
- }
+ }
if (0 != setsockopt(ret, SOL_SOCKET, SO_BROADCAST, (char*)&bOptVal, bOptLen))
{
- fprintf(stderr,
+ fprintf(stderr,
"Error setting SO_BROADCAST to ON: %s\n",
strerror (errno));
closesocket(rawsock);
if (0 != setsockopt(ret, IPPROTO_IP, IP_HDRINCL, (char*)&bOptVal, bOptLen))
{
- fprintf(stderr,
+ fprintf(stderr,
"Error setting IP_HDRINCL to ON: %s\n",
strerror (errno));
closesocket(rawsock);
fprintf (stderr, "Failed to find Winsock 2.1 or better.\n");
return 2;
}
- if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
+ if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
{
fprintf (stderr,
"Internal error converting dummy IP to binary.\n");