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templ-pkt.c
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/*
Construct a TCP packet based upon a template.
The (eventual) idea of this module is to make this scanner extensible
by providing an arbitrary packet template. Thus, the of this module
is to take an existing packet template, parse it, then make
appropriate changes.
*/
#include "templ-pkt.h"
#include "templ-tcp-hdr.h"
#include "templ-opts.h"
#include "massip-port.h"
#include "proto-preprocess.h"
#include "proto-sctp.h"
#include "string_s.h"
#include "pixie-timer.h"
#include "logger.h"
#include "templ-payloads.h"
#include "syn-cookie.h"
#include "unusedparm.h"
#include "vulncheck.h"
#include "util-checksum.h"
#include "util-malloc.h"
#include "stub-pcap-dlt.h" /* data link types, like NULL, RAW, or ETHERNET */
#include <assert.h>
#include <string.h>
#include <stdlib.h>
static unsigned char default_tcp_template[] =
"\0\1\2\3\4\5" /* Ethernet: destination */
"\6\7\x8\x9\xa\xb" /* Ethernet: source */
"\x08\x00" /* Ethernet type: IPv4 */
"\x45" /* IP type */
"\x00"
"\x00\x2c" /* total length = 40 bytes */
"\x00\x00" /* identification */
"\x00\x00" /* fragmentation flags */
"\xFF\x06" /* TTL=255, proto=TCP */
"\xFF\xFF" /* checksum */
"\0\0\0\0" /* source address */
"\0\0\0\0" /* destination address */
"\0\0" /* source port */
"\0\0" /* destination port */
"\0\0\0\0" /* sequence number */
"\0\0\0\0" /* ACK number */
"\x60" /* header length */
"\x02" /* SYN */
"\x04\x01" /* window fixed to 1024 */
"\xFF\xFF" /* checksum */
"\x00\x00" /* urgent pointer */
"\x02\x04\x05\xb4" /* opt [mss 1460] h/t @IvreRocks */
;
static unsigned char default_udp_template[] =
"\0\1\2\3\4\5" /* Ethernet: destination */
"\6\7\x8\x9\xa\xb" /* Ethernet: source */
"\x08\x00" /* Ethernet type: IPv4 */
"\x45" /* IP type */
"\x00"
"\x00\x1c" /* total length = 28 bytes */
"\x00\x00" /* identification */
"\x00\x00" /* fragmentation flags */
"\xFF\x11" /* TTL=255, proto=UDP */
"\xFF\xFF" /* checksum */
"\0\0\0\0" /* source address */
"\0\0\0\0" /* destination address */
"\xfe\xdc" /* source port */
"\x00\x00" /* destination port */
"\x00\x08" /* length */
"\x00\x00" /* checksum */
;
static unsigned char default_sctp_template[] =
"\0\1\2\3\4\5" /* Ethernet: destination */
"\6\7\x8\x9\xa\xb" /* Ethernet: source */
"\x08\x00" /* Ethernet type: IPv4 */
"\x45" /* IP type */
"\x00"
"\x00\x34" /* total length = 52 bytes */
"\x00\x00" /* identification */
"\x00\x00" /* fragmentation flags */
"\xFF\x84" /* TTL=255, proto = SCTP */
"\x00\x00" /* checksum */
"\0\0\0\0" /* source address */
"\0\0\0\0" /* destination address */
"\x00\x00" /* source port */
"\x00\x00" /* destination port */
"\x00\x00\x00\x00" /* verification tag */
"\x58\xe4\x5d\x36" /* checksum */
"\x01" /* type = init */
"\x00" /* flags = none */
"\x00\x14" /* length = 20 */
"\x9e\x8d\x52\x25" /* initiate tag */
"\x00\x00\x80\x00" /* receiver window credit */
"\x00\x0a" /* outbound streams = 10 */
"\x08\x00" /* inbound streams = 2048 */
"\x46\x1a\xdf\x3d" /* initial TSN */
;
static unsigned char default_icmp_ping_template[] =
"\0\1\2\3\4\5" /* Ethernet: destination */
"\6\7\x8\x9\xa\xb" /* Ethernet: source */
"\x08\x00" /* Ethernet type: IPv4 */
"\x45" /* IP type */
"\x00"
"\x00\x4c" /* total length = 76 bytes */
"\x00\x00" /* identification */
"\x00\x00" /* fragmentation flags */
"\xFF\x01" /* TTL=255, proto=ICMP */
"\xFF\xFF" /* checksum */
"\0\0\0\0" /* source address */
"\0\0\0\0" /* destination address */
"\x08\x00" /* Ping Request */
"\x00\x00" /* checksum */
"\x00\x00\x00\x00" /* ID, seqno */
"\x08\x09\x0a\x0b" /* payload */
"\x0c\x0d\x0e\x0f"
"\x10\x11\x12\x13"
"\x14\x15\x16\x17"
"\x18\x19\x1a\x1b"
"\x1c\x1d\x1e\x1f"
"\x20\x21\x22\x23"
"\x24\x25\x26\x27"
"\x28\x29\x2a\x2b"
"\x2c\x2d\x2e\x2f"
"\x30\x31\x32\x33"
"\x34\x35\x36\x37"
;
static unsigned char default_icmp_timestamp_template[] =
"\0\1\2\3\4\5" /* Ethernet: destination */
"\6\7\x8\x9\xa\xb" /* Ethernet: source */
"\x08\x00" /* Ethernet type: IPv4 */
"\x45" /* IP type */
"\x00"
"\x00\x28" /* total length = 84 bytes */
"\x00\x00" /* identification */
"\x00\x00" /* fragmentation flags */
"\xFF\x01" /* TTL=255, proto=UDP */
"\xFF\xFF" /* checksum */
"\0\0\0\0" /* source address */
"\0\0\0\0" /* destination address */
"\x0d\x00" /* timestamp request */
"\x00\x00" /* checksum */
"\x00\x00" /* identifier */
"\x00\x00" /* sequence number */
"\x00\x00\x00\x00"
"\x00\x00\x00\x00"
"\x00\x00\x00\x00"
;
static unsigned char default_arp_template[] =
"\xff\xff\xff\xff\xff\xff" /* Ethernet: destination */
"\x00\x00\x00\x00\x00\x00" /* Ethernet: source */
"\x08\x06" /* Ethernet type: ARP */
"\x00\x01" /* hardware = Ethernet */
"\x08\x00" /* protocol = IPv4 */
"\x06\x04" /* MAC length = 6, IPv4 length = 4 */
"\x00\x01" /* opcode = request */
"\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00"
;
/***************************************************************************
* Checksum the IP header. This is a "partial" checksum, so we
* don't reverse the bits ~.
***************************************************************************/
static unsigned
ip_header_checksum(const unsigned char *px, unsigned offset, unsigned max_offset)
{
unsigned header_length = (px[offset]&0xF) * 4;
unsigned xsum = 0;
unsigned i;
/* restrict check only over packet */
if (max_offset > offset + header_length)
max_offset = offset + header_length;
/* add all the two-byte words together */
xsum = 0;
for (i = offset; i < max_offset; i += 2) {
xsum += px[i]<<8 | px[i+1];
}
/* if more than 16 bits in result, reduce to 16 bits */
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
return xsum;
}
/***************************************************************************
***************************************************************************/
static unsigned
tcp_checksum2(const unsigned char *px, unsigned offset_ip,
unsigned offset_tcp, size_t tcp_length)
{
uint64_t xsum = 0;
unsigned i;
/* pseudo checksum */
xsum = 6;
xsum += tcp_length;
xsum += px[offset_ip + 12] << 8 | px[offset_ip + 13];
xsum += px[offset_ip + 14] << 8 | px[offset_ip + 15];
xsum += px[offset_ip + 16] << 8 | px[offset_ip + 17];
xsum += px[offset_ip + 18] << 8 | px[offset_ip + 19];
/* TCP checksum */
for (i=0; i<tcp_length; i += 2) {
xsum += px[offset_tcp + i]<<8 | px[offset_tcp + i + 1];
}
xsum -= (tcp_length & 1) * px[offset_tcp + i - 1]; /* yea I know going off end of packet is bad so sue me */
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
return (unsigned)xsum;
}
/***************************************************************************
***************************************************************************/
/***************************************************************************
***************************************************************************/
static unsigned
tcp_ipv4_checksum(struct TemplatePacket *tmpl)
{
const unsigned char *px = tmpl->ipv4.packet;
unsigned offset_ip = tmpl->ipv4.offset_ip;
unsigned offset_app = tmpl->ipv4.offset_app;
unsigned offset_tcp = tmpl->ipv4.offset_tcp;
unsigned xsum = 0;
unsigned i;
/* pseudo checksum */
xsum = 6;
xsum += offset_app - offset_tcp;
xsum += px[offset_ip + 12] << 8 | px[offset_ip + 13];
xsum += px[offset_ip + 14] << 8 | px[offset_ip + 15];
xsum += px[offset_ip + 16] << 8 | px[offset_ip + 17];
xsum += px[offset_ip + 18] << 8 | px[offset_ip + 19];
/* TCP checksum */
for (i=offset_tcp; i<offset_app; i += 2) {
xsum += px[i]<<8 | px[i+1];
}
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
return xsum;
}
/***************************************************************************
***************************************************************************/
unsigned
udp_checksum2(const unsigned char *px, unsigned offset_ip,
unsigned offset_tcp, size_t tcp_length)
{
uint64_t xsum = 0;
unsigned i;
/* pseudo checksum */
xsum = 17;
xsum += tcp_length;
xsum += px[offset_ip + 12] << 8 | px[offset_ip + 13];
xsum += px[offset_ip + 14] << 8 | px[offset_ip + 15];
xsum += px[offset_ip + 16] << 8 | px[offset_ip + 17];
xsum += px[offset_ip + 18] << 8 | px[offset_ip + 19];
/* TCP checksum */
for (i=0; i<tcp_length; i += 2) {
xsum += px[offset_tcp + i]<<8 | px[offset_tcp + i + 1];
}
xsum -= (tcp_length & 1) * px[offset_tcp + i - 1]; /* yea I know going off end of packet is bad so sue me */
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
return (unsigned)xsum;
}
/***************************************************************************
***************************************************************************/
static unsigned
udp_ipv4_checksum(struct TemplatePacket *tmpl)
{
return udp_checksum2(
tmpl->ipv4.packet,
tmpl->ipv4.offset_ip,
tmpl->ipv4.offset_tcp,
tmpl->ipv4.length - tmpl->ipv4.offset_tcp);
}
/***************************************************************************
***************************************************************************/
static unsigned
icmp_checksum2(const unsigned char *px,
unsigned offset_icmp, size_t icmp_length)
{
uint64_t xsum = 0;
unsigned i;
for (i=0; i<icmp_length; i += 2) {
xsum += px[offset_icmp + i]<<8 | px[offset_icmp + i + 1];
}
xsum -= (icmp_length & 1) * px[offset_icmp + i - 1]; /* yea I know going off end of packet is bad so sue me */
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
xsum = (xsum & 0xFFFF) + (xsum >> 16);
return (unsigned)xsum;
}
/***************************************************************************
***************************************************************************/
static unsigned
icmp_ipv4_checksum(struct TemplatePacket *tmpl)
{
return icmp_checksum2(
tmpl->ipv4.packet,
tmpl->ipv4.offset_tcp,
tmpl->ipv4.length - tmpl->ipv4.offset_tcp);
}
/***************************************************************************
***************************************************************************/
struct TemplateSet templ_copy(const struct TemplateSet *templset)
{
struct TemplateSet result;
unsigned i;
memcpy(&result, templset, sizeof(result));
for (i=0; i<templset->count; i++) {
const struct TemplatePacket *p1 = &templset->pkts[i];
struct TemplatePacket *p2 = &result.pkts[i];
p2->ipv4.packet = MALLOC(2048+p2->ipv4.length);
memcpy(p2->ipv4.packet, p1->ipv4.packet, p2->ipv4.length);
p2->ipv6.packet = MALLOC(2048+p2->ipv6.length);
memcpy(p2->ipv6.packet, p1->ipv6.packet, p2->ipv6.length);
}
return result;
}
/***************************************************************************
***************************************************************************/
void
tcp_set_window(unsigned char *px, size_t px_length, unsigned window)
{
struct PreprocessedInfo parsed;
unsigned x;
size_t offset;
unsigned xsum;
/* Parse the frame looking for the TCP header */
x = preprocess_frame(px, (unsigned)px_length, 1 /*enet*/, &parsed);
if (!x || parsed.found == FOUND_NOTHING)
return;
if (parsed.ip_protocol != 6)
return;
offset = parsed.transport_offset;
if (offset + 20 > px_length)
return;
/* set the new window */
#if 0
xsum = px[offset + 16] << 8 | px[offset + 17];
xsum = (~xsum)&0xFFFF;
xsum += window & 0xFFFF;
xsum -= px[offset + 14] << 8 | px[offset + 15];
xsum = ((xsum)&0xFFFF) + (xsum >> 16);
xsum = ((xsum)&0xFFFF) + (xsum >> 16);
xsum = ((xsum)&0xFFFF) + (xsum >> 16);
xsum = (~xsum)&0xFFFF;
#endif
px[offset + 14] = (unsigned char)(window>>8);
px[offset + 15] = (unsigned char)(window>>0);
px[offset + 16] = (unsigned char)(0);
px[offset + 17] = (unsigned char)(0);
xsum = ~tcp_checksum2(px, parsed.ip_offset, parsed.transport_offset,
parsed.transport_length);
px[offset + 16] = (unsigned char)(xsum>>8);
px[offset + 17] = (unsigned char)(xsum>>0);
}
/***************************************************************************
***************************************************************************/
size_t
tcp_create_packet(
struct TemplatePacket *tmpl,
ipaddress ip_them, unsigned port_them,
ipaddress ip_me, unsigned port_me,
unsigned seqno, unsigned ackno,
unsigned flags,
const unsigned char *payload, size_t payload_length,
unsigned char *px, size_t px_length)
{
uint64_t xsum;
if (ip_them.version == 4) {
unsigned ip_id = ip_them.ipv4 ^ port_them ^ seqno;
unsigned offset_ip = tmpl->ipv4.offset_ip;
unsigned offset_tcp = tmpl->ipv4. offset_tcp;
unsigned offset_payload = offset_tcp + ((tmpl->ipv4.packet[offset_tcp+12]&0xF0)>>2);
size_t new_length = offset_payload + payload_length;
size_t ip_len = (offset_payload - offset_ip) + payload_length;
unsigned old_len;
if (new_length > px_length) {
fprintf(stderr, "tcp: err generating packet: too much payload\n");
return 0;
}
memcpy(px + 0, tmpl->ipv4.packet, tmpl->ipv4.length);
memcpy(px + offset_payload, payload, payload_length);
old_len = px[offset_ip+2]<<8 | px[offset_ip+3];
/*
* Fill in the empty fields in the IP header and then re-calculate
* the checksum.
*/
px[offset_ip+2] = (unsigned char)(ip_len>> 8);
px[offset_ip+3] = (unsigned char)(ip_len & 0xFF);
px[offset_ip+4] = (unsigned char)(ip_id >> 8);
px[offset_ip+5] = (unsigned char)(ip_id & 0xFF);
px[offset_ip+12] = (unsigned char)((ip_me.ipv4 >> 24) & 0xFF);
px[offset_ip+13] = (unsigned char)((ip_me.ipv4 >> 16) & 0xFF);
px[offset_ip+14] = (unsigned char)((ip_me.ipv4 >> 8) & 0xFF);
px[offset_ip+15] = (unsigned char)((ip_me.ipv4 >> 0) & 0xFF);
px[offset_ip+16] = (unsigned char)((ip_them.ipv4 >> 24) & 0xFF);
px[offset_ip+17] = (unsigned char)((ip_them.ipv4 >> 16) & 0xFF);
px[offset_ip+18] = (unsigned char)((ip_them.ipv4 >> 8) & 0xFF);
px[offset_ip+19] = (unsigned char)((ip_them.ipv4 >> 0) & 0xFF);
xsum = tmpl->ipv4.checksum_ip;
xsum += (ip_id&0xFFFF);
xsum += ip_me.ipv4;
xsum += ip_them.ipv4;
xsum += ip_len - old_len;
xsum = (xsum >> 16) + (xsum & 0xFFFF);
xsum = (xsum >> 16) + (xsum & 0xFFFF);
xsum = ~xsum;
px[offset_ip+10] = (unsigned char)(xsum >> 8);
px[offset_ip+11] = (unsigned char)(xsum & 0xFF);
/*
* now do the same for TCP
*/
px[offset_tcp+ 0] = (unsigned char)(port_me >> 8);
px[offset_tcp+ 1] = (unsigned char)(port_me & 0xFF);
px[offset_tcp+ 2] = (unsigned char)(port_them >> 8);
px[offset_tcp+ 3] = (unsigned char)(port_them & 0xFF);
px[offset_tcp+ 4] = (unsigned char)(seqno >> 24);
px[offset_tcp+ 5] = (unsigned char)(seqno >> 16);
px[offset_tcp+ 6] = (unsigned char)(seqno >> 8);
px[offset_tcp+ 7] = (unsigned char)(seqno >> 0);
px[offset_tcp+ 8] = (unsigned char)(ackno >> 24);
px[offset_tcp+ 9] = (unsigned char)(ackno >> 16);
px[offset_tcp+10] = (unsigned char)(ackno >> 8);
px[offset_tcp+11] = (unsigned char)(ackno >> 0);
px[offset_tcp+13] = (unsigned char)flags;
px[offset_tcp+14] = (unsigned char)(1200>>8);
px[offset_tcp+15] = (unsigned char)(1200 & 0xFF);
px[offset_tcp+16] = (unsigned char)(0 >> 8);
px[offset_tcp+17] = (unsigned char)(0 >> 0);
xsum = tcp_checksum2(px, tmpl->ipv4.offset_ip, tmpl->ipv4.offset_tcp,
new_length - tmpl->ipv4.offset_tcp);
xsum = ~xsum;
px[offset_tcp+16] = (unsigned char)(xsum >> 8);
px[offset_tcp+17] = (unsigned char)(xsum >> 0);
if (new_length < 60) {
memset(px+new_length, 0, 60-new_length);
new_length = 60;
}
return new_length;
} else {
unsigned offset_ip = tmpl->ipv6.offset_ip;
unsigned offset_tcp = tmpl->ipv6.offset_tcp;
unsigned offset_app = tmpl->ipv6.offset_app;
/* Make sure the new packet won't exceed buffer size */
if (offset_app + payload_length > px_length) {
fprintf(stderr, "tcp: err generating packet: too much payload\n");
return 0;
}
/* Copy over everything up to the new application-layer-payload */
memcpy(px, tmpl->ipv6.packet, tmpl->ipv6.offset_app);
/* Replace the template's application-layer-payload with the new app-payload */
memcpy(px + tmpl->ipv6.offset_app, payload, payload_length);
/* Fixup the "payload length" field in the IPv6 header. This is everything
* after the IPv6 header. There may be additional headers between the IPv6
* and TCP headers, so the calculation isn't simply the length of the TCP portion */
{
size_t len = tmpl->ipv6.offset_app + payload_length - tmpl->ipv6.offset_ip - 40;
px[offset_ip + 4] = (unsigned char)(len>>8) & 0xFF;
px[offset_ip + 5] = (unsigned char)(len>>0) & 0xFF;
}
/* Copy over the IP addresses */
px[offset_ip+ 8] = (unsigned char)((ip_me.ipv6.hi >> 56ULL) & 0xFF);
px[offset_ip+ 9] = (unsigned char)((ip_me.ipv6.hi >> 48ULL) & 0xFF);
px[offset_ip+10] = (unsigned char)((ip_me.ipv6.hi >> 40ULL) & 0xFF);
px[offset_ip+11] = (unsigned char)((ip_me.ipv6.hi >> 32ULL) & 0xFF);
px[offset_ip+12] = (unsigned char)((ip_me.ipv6.hi >> 24ULL) & 0xFF);
px[offset_ip+13] = (unsigned char)((ip_me.ipv6.hi >> 16ULL) & 0xFF);
px[offset_ip+14] = (unsigned char)((ip_me.ipv6.hi >> 8ULL) & 0xFF);
px[offset_ip+15] = (unsigned char)((ip_me.ipv6.hi >> 0ULL) & 0xFF);
px[offset_ip+16] = (unsigned char)((ip_me.ipv6.lo >> 56ULL) & 0xFF);
px[offset_ip+17] = (unsigned char)((ip_me.ipv6.lo >> 48ULL) & 0xFF);
px[offset_ip+18] = (unsigned char)((ip_me.ipv6.lo >> 40ULL) & 0xFF);
px[offset_ip+19] = (unsigned char)((ip_me.ipv6.lo >> 32ULL) & 0xFF);
px[offset_ip+20] = (unsigned char)((ip_me.ipv6.lo >> 24ULL) & 0xFF);
px[offset_ip+21] = (unsigned char)((ip_me.ipv6.lo >> 16ULL) & 0xFF);
px[offset_ip+22] = (unsigned char)((ip_me.ipv6.lo >> 8ULL) & 0xFF);
px[offset_ip+23] = (unsigned char)((ip_me.ipv6.lo >> 0ULL) & 0xFF);
px[offset_ip+24] = (unsigned char)((ip_them.ipv6.hi >> 56ULL) & 0xFF);
px[offset_ip+25] = (unsigned char)((ip_them.ipv6.hi >> 48ULL) & 0xFF);
px[offset_ip+26] = (unsigned char)((ip_them.ipv6.hi >> 40ULL) & 0xFF);
px[offset_ip+27] = (unsigned char)((ip_them.ipv6.hi >> 32ULL) & 0xFF);
px[offset_ip+28] = (unsigned char)((ip_them.ipv6.hi >> 24ULL) & 0xFF);
px[offset_ip+29] = (unsigned char)((ip_them.ipv6.hi >> 16ULL) & 0xFF);
px[offset_ip+30] = (unsigned char)((ip_them.ipv6.hi >> 8ULL) & 0xFF);
px[offset_ip+31] = (unsigned char)((ip_them.ipv6.hi >> 0ULL) & 0xFF);
px[offset_ip+32] = (unsigned char)((ip_them.ipv6.lo >> 56ULL) & 0xFF);
px[offset_ip+33] = (unsigned char)((ip_them.ipv6.lo >> 48ULL) & 0xFF);
px[offset_ip+34] = (unsigned char)((ip_them.ipv6.lo >> 40ULL) & 0xFF);
px[offset_ip+35] = (unsigned char)((ip_them.ipv6.lo >> 32ULL) & 0xFF);
px[offset_ip+36] = (unsigned char)((ip_them.ipv6.lo >> 24ULL) & 0xFF);
px[offset_ip+37] = (unsigned char)((ip_them.ipv6.lo >> 16ULL) & 0xFF);
px[offset_ip+38] = (unsigned char)((ip_them.ipv6.lo >> 8ULL) & 0xFF);
px[offset_ip+39] = (unsigned char)((ip_them.ipv6.lo >> 0ULL) & 0xFF);
/*
* now do the same for TCP
*/
px[offset_tcp+ 0] = (unsigned char)(port_me >> 8);
px[offset_tcp+ 1] = (unsigned char)(port_me & 0xFF);
px[offset_tcp+ 2] = (unsigned char)(port_them >> 8);
px[offset_tcp+ 3] = (unsigned char)(port_them & 0xFF);
px[offset_tcp+ 4] = (unsigned char)(seqno >> 24);
px[offset_tcp+ 5] = (unsigned char)(seqno >> 16);
px[offset_tcp+ 6] = (unsigned char)(seqno >> 8);
px[offset_tcp+ 7] = (unsigned char)(seqno >> 0);
px[offset_tcp+ 8] = (unsigned char)(ackno >> 24);
px[offset_tcp+ 9] = (unsigned char)(ackno >> 16);
px[offset_tcp+10] = (unsigned char)(ackno >> 8);
px[offset_tcp+11] = (unsigned char)(ackno >> 0);
px[offset_tcp+13] = (unsigned char)flags;
px[offset_tcp+14] = (unsigned char)(1200>>8);
px[offset_tcp+15] = (unsigned char)(1200 & 0xFF);
px[offset_tcp+16] = (unsigned char)(0 >> 8);
px[offset_tcp+17] = (unsigned char)(0 >> 0);
xsum = checksum_ipv6(px + offset_ip + 8, px + offset_ip + 24, 6, (offset_app - offset_tcp) + payload_length, px + offset_tcp);
px[offset_tcp+16] = (unsigned char)(xsum >> 8);
px[offset_tcp+17] = (unsigned char)(xsum >> 0);
px[offset_tcp+16] = (unsigned char)(xsum >> 8);
px[offset_tcp+17] = (unsigned char)(xsum >> 0);
return offset_app + payload_length;
}
}
/***************************************************************************
***************************************************************************/
static void
udp_payload_fixup(struct TemplatePacket *tmpl, unsigned port, unsigned seqno)
{
const unsigned char *px2 = 0;
unsigned length2 = 0;
unsigned source_port2 = 0x1000;
uint64_t xsum2 = 0;
//unsigned char *px = tmpl->packet;
SET_COOKIE set_cookie = 0;
UNUSEDPARM(seqno);
payloads_udp_lookup(tmpl->payloads,
port,
&px2,
&length2,
&source_port2,
&xsum2,
&set_cookie);
/* Copy over the payloads */
memcpy( tmpl->ipv4.packet + tmpl->ipv4.offset_app,
px2,
length2);
memcpy( tmpl->ipv6.packet + tmpl->ipv6.offset_app,
px2,
length2);
/* Change the cookie values */
if (set_cookie) {
set_cookie(
tmpl->ipv4.packet + tmpl->ipv4.offset_app,
length2,
seqno);
set_cookie(
tmpl->ipv6.packet + tmpl->ipv6.offset_app,
length2,
seqno);
}
tmpl->ipv4.length = tmpl->ipv4.offset_app + length2;
tmpl->ipv6.length = tmpl->ipv6.offset_app + length2;
}
void
template_set_target_ipv6(
struct TemplateSet *tmplset,
ipv6address ip_them, unsigned port_them,
ipv6address ip_me, unsigned port_me,
unsigned seqno,
unsigned char *px, size_t sizeof_px, size_t *r_length
)
{
unsigned offset_ip;
unsigned offset_tcp;
uint64_t xsum;
struct TemplatePacket *tmpl = NULL;
uint64_t entropy = tmplset->entropy;
unsigned payload_length;
*r_length = sizeof_px;
/*
* Find out which packet template to use. This is because we can
* simultaneously scan for both TCP and UDP (and others). We've
* just overloaded the "port" field to signal which protocol we
* are using
*/
if (port_them < Templ_TCP + 65536)
tmpl = &tmplset->pkts[Proto_TCP];
else if (port_them < Templ_UDP + 65536) {
tmpl = &tmplset->pkts[Proto_UDP];
port_them &= 0xFFFF;
udp_payload_fixup(tmpl, port_them, seqno);
} else if (port_them < Templ_SCTP + 65536) {
tmpl = &tmplset->pkts[Proto_SCTP];
port_them &= 0xFFFF;
} else if (port_them == Templ_ICMP_echo) {
tmpl = &tmplset->pkts[Proto_ICMP_ping];
} else if (port_them == Templ_ICMP_timestamp) {
tmpl = &tmplset->pkts[Proto_ICMP_timestamp];
} else if (port_them == Templ_ARP) {
tmpl = &tmplset->pkts[Proto_ARP];
if (*r_length > tmpl->ipv6.length)
*r_length = tmpl->ipv6.length;
memcpy(px, tmpl->ipv6.packet, *r_length);
return;
} else if (port_them == Templ_VulnCheck) {
tmpl = &tmplset->pkts[Proto_VulnCheck];
port_them &= 0xFFFF;
} else {
return;
}
/* Create some shorter local variables to work with */
if (*r_length > tmpl->ipv6.length)
*r_length = tmpl->ipv6.length;
memcpy(px, tmpl->ipv6.packet, *r_length);
offset_ip = tmpl->ipv6.offset_ip;
offset_tcp = tmpl->ipv6.offset_tcp;
//ip_id = ip_them ^ port_them ^ seqno;
/*
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Traffic Class | Flow Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | Next Header | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Source Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Destination Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
/*
* Fill in the empty fields in the IP header and then re-calculate
* the checksum.
*/
payload_length = tmpl->ipv6.length - tmpl->ipv6.offset_ip - 40;
px[offset_ip+4] = (unsigned char)(payload_length>>8);
px[offset_ip+5] = (unsigned char)(payload_length>>0);
px[offset_ip+ 8] = (unsigned char)((ip_me.hi >> 56ULL) & 0xFF);
px[offset_ip+ 9] = (unsigned char)((ip_me.hi >> 48ULL) & 0xFF);
px[offset_ip+10] = (unsigned char)((ip_me.hi >> 40ULL) & 0xFF);
px[offset_ip+11] = (unsigned char)((ip_me.hi >> 32ULL) & 0xFF);
px[offset_ip+12] = (unsigned char)((ip_me.hi >> 24ULL) & 0xFF);
px[offset_ip+13] = (unsigned char)((ip_me.hi >> 16ULL) & 0xFF);
px[offset_ip+14] = (unsigned char)((ip_me.hi >> 8ULL) & 0xFF);
px[offset_ip+15] = (unsigned char)((ip_me.hi >> 0ULL) & 0xFF);
px[offset_ip+16] = (unsigned char)((ip_me.lo >> 56ULL) & 0xFF);
px[offset_ip+17] = (unsigned char)((ip_me.lo >> 48ULL) & 0xFF);
px[offset_ip+18] = (unsigned char)((ip_me.lo >> 40ULL) & 0xFF);
px[offset_ip+19] = (unsigned char)((ip_me.lo >> 32ULL) & 0xFF);
px[offset_ip+20] = (unsigned char)((ip_me.lo >> 24ULL) & 0xFF);
px[offset_ip+21] = (unsigned char)((ip_me.lo >> 16ULL) & 0xFF);
px[offset_ip+22] = (unsigned char)((ip_me.lo >> 8ULL) & 0xFF);
px[offset_ip+23] = (unsigned char)((ip_me.lo >> 0ULL) & 0xFF);
px[offset_ip+24] = (unsigned char)((ip_them.hi >> 56ULL) & 0xFF);
px[offset_ip+25] = (unsigned char)((ip_them.hi >> 48ULL) & 0xFF);
px[offset_ip+26] = (unsigned char)((ip_them.hi >> 40ULL) & 0xFF);
px[offset_ip+27] = (unsigned char)((ip_them.hi >> 32ULL) & 0xFF);
px[offset_ip+28] = (unsigned char)((ip_them.hi >> 24ULL) & 0xFF);
px[offset_ip+29] = (unsigned char)((ip_them.hi >> 16ULL) & 0xFF);
px[offset_ip+30] = (unsigned char)((ip_them.hi >> 8ULL) & 0xFF);
px[offset_ip+31] = (unsigned char)((ip_them.hi >> 0ULL) & 0xFF);
px[offset_ip+32] = (unsigned char)((ip_them.lo >> 56ULL) & 0xFF);
px[offset_ip+33] = (unsigned char)((ip_them.lo >> 48ULL) & 0xFF);
px[offset_ip+34] = (unsigned char)((ip_them.lo >> 40ULL) & 0xFF);
px[offset_ip+35] = (unsigned char)((ip_them.lo >> 32ULL) & 0xFF);
px[offset_ip+36] = (unsigned char)((ip_them.lo >> 24ULL) & 0xFF);
px[offset_ip+37] = (unsigned char)((ip_them.lo >> 16ULL) & 0xFF);
px[offset_ip+38] = (unsigned char)((ip_them.lo >> 8ULL) & 0xFF);
px[offset_ip+39] = (unsigned char)((ip_them.lo >> 0ULL) & 0xFF);
/*
* Now do the checksum for the higher layer protocols
*/
switch (tmpl->proto) {
case Proto_TCP:
px[offset_tcp+ 0] = (unsigned char)(port_me >> 8);
px[offset_tcp+ 1] = (unsigned char)(port_me & 0xFF);
px[offset_tcp+ 2] = (unsigned char)(port_them >> 8);
px[offset_tcp+ 3] = (unsigned char)(port_them & 0xFF);
px[offset_tcp+ 4] = (unsigned char)(seqno >> 24);
px[offset_tcp+ 5] = (unsigned char)(seqno >> 16);
px[offset_tcp+ 6] = (unsigned char)(seqno >> 8);
px[offset_tcp+ 7] = (unsigned char)(seqno >> 0);
xsum = checksum_ipv6(px + offset_ip + 8, px + offset_ip + 24, 6, tmpl->ipv6.length - offset_tcp, px + offset_tcp);
px[offset_tcp+16] = (unsigned char)(xsum >> 8);
px[offset_tcp+17] = (unsigned char)(xsum >> 0);
break;
case Proto_UDP:
/* TODO: IPv6 */
px[offset_tcp+ 0] = (unsigned char)(port_me >> 8);
px[offset_tcp+ 1] = (unsigned char)(port_me & 0xFF);
px[offset_tcp+ 2] = (unsigned char)(port_them >> 8);
px[offset_tcp+ 3] = (unsigned char)(port_them & 0xFF);
px[offset_tcp+ 4] = (unsigned char)((tmpl->ipv6.length - tmpl->ipv6.offset_app + 8)>>8);
px[offset_tcp+ 5] = (unsigned char)((tmpl->ipv6.length - tmpl->ipv6.offset_app + 8)&0xFF);
px[offset_tcp+6] = (unsigned char)(0);
px[offset_tcp+7] = (unsigned char)(0);
xsum = checksum_ipv6(px + offset_ip + 8, px + offset_ip + 24, 17, tmpl->ipv6.length - offset_tcp, px + offset_tcp);
px[offset_tcp+6] = (unsigned char)(xsum >> 8);
px[offset_tcp+7] = (unsigned char)(xsum >> 0);
break;
case Proto_SCTP:
/* TODO: IPv6 */
px[offset_tcp+ 0] = (unsigned char)(port_me >> 8);
px[offset_tcp+ 1] = (unsigned char)(port_me & 0xFF);
px[offset_tcp+ 2] = (unsigned char)(port_them >> 8);
px[offset_tcp+ 3] = (unsigned char)(port_them & 0xFF);
px[offset_tcp+16] = (unsigned char)(seqno >> 24);
px[offset_tcp+17] = (unsigned char)(seqno >> 16);
px[offset_tcp+18] = (unsigned char)(seqno >> 8);
px[offset_tcp+19] = (unsigned char)(seqno >> 0);
xsum = sctp_checksum(px + offset_tcp, tmpl->ipv6.length - offset_tcp);
px[offset_tcp+ 8] = (unsigned char)(xsum >> 24);
px[offset_tcp+ 9] = (unsigned char)(xsum >> 16);
px[offset_tcp+10] = (unsigned char)(xsum >> 8);
px[offset_tcp+11] = (unsigned char)(xsum >> 0);
break;
case Proto_ICMP_ping:
case Proto_ICMP_timestamp:
/* TODO: IPv6 */
seqno = (unsigned)syn_cookie_ipv6(ip_them, port_them, ip_me, 0, entropy);
px[offset_tcp+ 4] = (unsigned char)(seqno >> 24);
px[offset_tcp+ 5] = (unsigned char)(seqno >> 16);
px[offset_tcp+ 6] = (unsigned char)(seqno >> 8);
px[offset_tcp+ 7] = (unsigned char)(seqno >> 0);
xsum = checksum_ipv6(px + offset_ip + 8, px + offset_ip + 24, 58, tmpl->ipv6.length - offset_tcp, px + offset_tcp);
px[offset_tcp+2] = (unsigned char)(xsum >> 8);
px[offset_tcp+3] = (unsigned char)(xsum >> 0);
break;
case Proto_VulnCheck:
/* TODO: IPv6 */
/*tmplset->vulncheck->set_target(tmpl,
ip_them, port_them,
ip_me, port_me,
seqno,
px, sizeof_px, r_length);*/
break;
case Proto_ARP:
/* TODO: IPv6 */
/* don't do any checksumming */
break;
case Proto_Oproto:
/* TODO: IPv6 */
/* TODO: probably need to add checksums for certain protocols */
break;
case Proto_Count:
break;
}
}
/***************************************************************************
* This is the function that formats the transmitted packets for probing
* machines. It takes a template for the protocol (usually a TCP SYN
* packet), then sets the destination IP address and port numbers.
***************************************************************************/
void
template_set_target_ipv4(
struct TemplateSet *tmplset,
ipv4address ip_them, unsigned port_them,
ipv4address ip_me, unsigned port_me,
unsigned seqno,
unsigned char *px, size_t sizeof_px, size_t *r_length
)
{
unsigned offset_ip;
unsigned offset_tcp;
uint64_t xsum;
unsigned ip_id;
struct TemplatePacket *tmpl = NULL;
unsigned xsum2;
uint64_t entropy = tmplset->entropy;
*r_length = sizeof_px;
/*
* Find out which packet template to use. This is because we can
* simultaneously scan for both TCP and UDP (and others). We've
* just overloaded the "port" field to signal which protocol we
* are using
*/
if (port_them < Templ_TCP + 65536)
tmpl = &tmplset->pkts[Proto_TCP];
else if (port_them < Templ_UDP + 65536) {
tmpl = &tmplset->pkts[Proto_UDP];
port_them &= 0xFFFF;
udp_payload_fixup(tmpl, port_them, seqno);
} else if (port_them < Templ_SCTP + 65536) {
tmpl = &tmplset->pkts[Proto_SCTP];
port_them &= 0xFFFF;
} else if (port_them == Templ_ICMP_echo) {
tmpl = &tmplset->pkts[Proto_ICMP_ping];
} else if (port_them == Templ_ICMP_timestamp) {
tmpl = &tmplset->pkts[Proto_ICMP_timestamp];
} else if (port_them == Templ_ARP) {
tmpl = &tmplset->pkts[Proto_ARP];
if (*r_length > tmpl->ipv4.length)
*r_length = tmpl->ipv4.length;
memcpy(px, tmpl->ipv4.packet, *r_length);
px = px + tmpl->ipv4.offset_ip;
px[14] = (unsigned char)((ip_me >> 24) & 0xFF);
px[15] = (unsigned char)((ip_me >> 16) & 0xFF);
px[16] = (unsigned char)((ip_me >> 8) & 0xFF);
px[17] = (unsigned char)((ip_me >> 0) & 0xFF);
px[24] = (unsigned char)((ip_them >> 24) & 0xFF);
px[25] = (unsigned char)((ip_them >> 16) & 0xFF);
px[26] = (unsigned char)((ip_them >> 8) & 0xFF);
px[27] = (unsigned char)((ip_them >> 0) & 0xFF);
return;
} else if (port_them == Templ_VulnCheck) {
tmpl = &tmplset->pkts[Proto_VulnCheck];
port_them &= 0xFFFF;
} else {
return;
}
/* Create some shorter local variables to work with */
if (*r_length > tmpl->ipv4.length)
*r_length = tmpl->ipv4.length;
memcpy(px, tmpl->ipv4.packet, *r_length);
offset_ip = tmpl->ipv4.offset_ip;
offset_tcp = tmpl->ipv4.offset_tcp;
ip_id = ip_them ^ port_them ^ seqno;
/*
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| IHL |Type of Service| Total Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time to Live | Protocol | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
/*
* Fill in the empty fields in the IP header and then re-calculate
* the checksum.
*/
{
unsigned total_length = tmpl->ipv4.length - tmpl->ipv4.offset_ip;
px[offset_ip+2] = (unsigned char)(total_length>>8);
px[offset_ip+3] = (unsigned char)(total_length>>0);
}
px[offset_ip+4] = (unsigned char)(ip_id >> 8);
px[offset_ip+5] = (unsigned char)(ip_id & 0xFF);
px[offset_ip+12] = (unsigned char)((ip_me >> 24) & 0xFF);
px[offset_ip+13] = (unsigned char)((ip_me >> 16) & 0xFF);
px[offset_ip+14] = (unsigned char)((ip_me >> 8) & 0xFF);
px[offset_ip+15] = (unsigned char)((ip_me >> 0) & 0xFF);
px[offset_ip+16] = (unsigned char)((ip_them >> 24) & 0xFF);
px[offset_ip+17] = (unsigned char)((ip_them >> 16) & 0xFF);
px[offset_ip+18] = (unsigned char)((ip_them >> 8) & 0xFF);
px[offset_ip+19] = (unsigned char)((ip_them >> 0) & 0xFF);
px[offset_ip+10] = (unsigned char)(0);
px[offset_ip+11] = (unsigned char)(0);
xsum2 = (unsigned)~ip_header_checksum(px, offset_ip, tmpl->ipv4.length);
px[offset_ip+10] = (unsigned char)(xsum2 >> 8);
px[offset_ip+11] = (unsigned char)(xsum2 & 0xFF);
/*
* Now do the checksum for the higher layer protocols
*/
xsum = 0;
switch (tmpl->proto) {
case Proto_TCP:
px[offset_tcp+ 0] = (unsigned char)(port_me >> 8);