mirror of
https://github.com/bol-van/zapret.git
synced 2024-11-11 17:29:16 +05:00
899 lines
32 KiB
C
899 lines
32 KiB
C
#define _GNU_SOURCE
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#include "desync.h"
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#include "protocol.h"
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#include "params.h"
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#include "helpers.h"
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#include "hostlist.h"
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#include "conntrack.h"
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#include <string.h>
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const char *fake_http_request_default = "GET / HTTP/1.1\r\nHost: www.w3.org\r\n"
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"User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0\r\n"
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"Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n"
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"Accept-Encoding: gzip, deflate\r\n\r\n";
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const uint8_t fake_tls_clienthello_default[517] = {
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0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x9a, 0x8f, 0xa7, 0x6a, 0x5d,
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0x57, 0xf3, 0x62, 0x19, 0xbe, 0x46, 0x82, 0x45, 0xe2, 0x59, 0x5c, 0xb4, 0x48, 0x31, 0x12, 0x15,
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0x14, 0x79, 0x2c, 0xaa, 0xcd, 0xea, 0xda, 0xf0, 0xe1, 0xfd, 0xbb, 0x20, 0xf4, 0x83, 0x2a, 0x94,
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0xf1, 0x48, 0x3b, 0x9d, 0xb6, 0x74, 0xba, 0x3c, 0x81, 0x63, 0xbc, 0x18, 0xcc, 0x14, 0x45, 0x57,
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0x6c, 0x80, 0xf9, 0x25, 0xcf, 0x9c, 0x86, 0x60, 0x50, 0x31, 0x2e, 0xe9, 0x00, 0x22, 0x13, 0x01,
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0x13, 0x03, 0x13, 0x02, 0xc0, 0x2b, 0xc0, 0x2f, 0xcc, 0xa9, 0xcc, 0xa8, 0xc0, 0x2c, 0xc0, 0x30,
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0xc0, 0x0a, 0xc0, 0x09, 0xc0, 0x13, 0xc0, 0x14, 0x00, 0x33, 0x00, 0x39, 0x00, 0x2f, 0x00, 0x35,
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0x01, 0x00, 0x01, 0x91, 0x00, 0x00, 0x00, 0x0f, 0x00, 0x0d, 0x00, 0x00, 0x0a, 0x77, 0x77, 0x77,
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0x2e, 0x77, 0x33, 0x2e, 0x6f, 0x72, 0x67, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00,
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0x00, 0x0a, 0x00, 0x0e, 0x00, 0x0c, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x19, 0x01, 0x00,
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0x01, 0x01, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00, 0x00, 0x23, 0x00, 0x00, 0x00, 0x10, 0x00, 0x0e,
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0x00, 0x0c, 0x02, 0x68, 0x32, 0x08, 0x68, 0x74, 0x74, 0x70, 0x2f, 0x31, 0x2e, 0x31, 0x00, 0x05,
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0x00, 0x05, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x33, 0x00, 0x6b, 0x00, 0x69, 0x00, 0x1d, 0x00,
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0x20, 0xb0, 0xe4, 0xda, 0x34, 0xb4, 0x29, 0x8d, 0xd3, 0x5c, 0x70, 0xd3, 0xbe, 0xe8, 0xa7, 0x2a,
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0x6b, 0xe4, 0x11, 0x19, 0x8b, 0x18, 0x9d, 0x83, 0x9a, 0x49, 0x7c, 0x83, 0x7f, 0xa9, 0x03, 0x8c,
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0x3c, 0x00, 0x17, 0x00, 0x41, 0x04, 0x4c, 0x04, 0xa4, 0x71, 0x4c, 0x49, 0x75, 0x55, 0xd1, 0x18,
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0x1e, 0x22, 0x62, 0x19, 0x53, 0x00, 0xde, 0x74, 0x2f, 0xb3, 0xde, 0x13, 0x54, 0xe6, 0x78, 0x07,
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0x94, 0x55, 0x0e, 0xb2, 0x6c, 0xb0, 0x03, 0xee, 0x79, 0xa9, 0x96, 0x1e, 0x0e, 0x98, 0x17, 0x78,
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0x24, 0x44, 0x0c, 0x88, 0x80, 0x06, 0x8b, 0xd4, 0x80, 0xbf, 0x67, 0x7c, 0x37, 0x6a, 0x5b, 0x46,
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0x4c, 0xa7, 0x98, 0x6f, 0xb9, 0x22, 0x00, 0x2b, 0x00, 0x09, 0x08, 0x03, 0x04, 0x03, 0x03, 0x03,
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0x02, 0x03, 0x01, 0x00, 0x0d, 0x00, 0x18, 0x00, 0x16, 0x04, 0x03, 0x05, 0x03, 0x06, 0x03, 0x08,
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0x04, 0x08, 0x05, 0x08, 0x06, 0x04, 0x01, 0x05, 0x01, 0x06, 0x01, 0x02, 0x03, 0x02, 0x01, 0x00,
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0x2d, 0x00, 0x02, 0x01, 0x01, 0x00, 0x1c, 0x00, 0x02, 0x40, 0x01, 0x00, 0x15, 0x00, 0x96, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00
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};
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#define PKTDATA_MAXDUMP 32
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#define IP_MAXDUMP 80
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static uint8_t zeropkt[DPI_DESYNC_MAX_FAKE_LEN];
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void desync_init()
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{
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memset(zeropkt, 0, sizeof(zeropkt));
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}
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bool desync_valid_zero_stage(enum dpi_desync_mode mode)
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{
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return mode==DESYNC_SYNACK;
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}
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bool desync_valid_first_stage(enum dpi_desync_mode mode)
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{
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return mode==DESYNC_FAKE || mode==DESYNC_FAKE_KNOWN || mode==DESYNC_RST || mode==DESYNC_RSTACK || mode==DESYNC_HOPBYHOP || mode==DESYNC_DESTOPT || mode==DESYNC_IPFRAG1;
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}
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bool desync_only_first_stage(enum dpi_desync_mode mode)
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{
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return false;
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}
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bool desync_valid_second_stage(enum dpi_desync_mode mode)
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{
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return mode==DESYNC_NONE || mode==DESYNC_DISORDER || mode==DESYNC_DISORDER2 || mode==DESYNC_SPLIT || mode==DESYNC_SPLIT2 || mode==DESYNC_IPFRAG2 || mode==DESYNC_UDPLEN;
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}
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bool desync_valid_second_stage_tcp(enum dpi_desync_mode mode)
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{
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return mode==DESYNC_NONE || mode==DESYNC_DISORDER || mode==DESYNC_DISORDER2 || mode==DESYNC_SPLIT || mode==DESYNC_SPLIT2 || mode==DESYNC_IPFRAG2;
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}
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bool desync_valid_second_stage_udp(enum dpi_desync_mode mode)
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{
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return mode==DESYNC_NONE || mode==DESYNC_UDPLEN || mode==DESYNC_IPFRAG2;
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}
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enum dpi_desync_mode desync_mode_from_string(const char *s)
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{
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if (!s)
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return DESYNC_NONE;
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else if (!strcmp(s,"fake"))
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return DESYNC_FAKE;
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else if (!strcmp(s,"fakeknown"))
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return DESYNC_FAKE_KNOWN;
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else if (!strcmp(s,"rst"))
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return DESYNC_RST;
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else if (!strcmp(s,"rstack"))
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return DESYNC_RSTACK;
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else if (!strcmp(s,"synack"))
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return DESYNC_SYNACK;
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else if (!strcmp(s,"disorder"))
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return DESYNC_DISORDER;
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else if (!strcmp(s,"disorder2"))
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return DESYNC_DISORDER2;
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else if (!strcmp(s,"split"))
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return DESYNC_SPLIT;
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else if (!strcmp(s,"split2"))
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return DESYNC_SPLIT2;
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else if (!strcmp(s,"ipfrag2"))
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return DESYNC_IPFRAG2;
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else if (!strcmp(s,"hopbyhop"))
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return DESYNC_HOPBYHOP;
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else if (!strcmp(s,"destopt"))
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return DESYNC_DESTOPT;
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else if (!strcmp(s,"ipfrag1"))
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return DESYNC_IPFRAG1;
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else if (!strcmp(s,"udplen"))
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return DESYNC_UDPLEN;
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return DESYNC_INVALID;
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}
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// auto creates internal socket and uses it for subsequent calls
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static bool rawsend_rep(const struct sockaddr* dst,uint32_t fwmark,const char *ifout,const void *data,size_t len)
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{
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for (int i=0;i<params.desync_repeats;i++)
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if (!rawsend(dst,fwmark,ifout,data,len))
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return false;
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return true;
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}
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static uint64_t cutoff_get_limit(t_ctrack *ctrack, char mode)
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{
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switch(mode)
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{
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case 'n': return ctrack->pcounter_orig;
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case 'd': return ctrack->pdcounter_orig;
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case 's': return ctrack->seq_last - ctrack->seq0;
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default: return 0;
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}
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}
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static bool cutoff_test(t_ctrack *ctrack, uint64_t cutoff, char mode)
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{
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return cutoff && cutoff_get_limit(ctrack, mode)>=cutoff;
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}
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static void maybe_cutoff(t_ctrack *ctrack, uint8_t proto)
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{
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if (ctrack)
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{
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if (proto==IPPROTO_TCP)
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ctrack->b_wssize_cutoff |= cutoff_test(ctrack, params.wssize_cutoff, params.wssize_cutoff_mode);
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ctrack->b_desync_cutoff |= cutoff_test(ctrack, params.desync_cutoff, params.desync_cutoff_mode);
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if (proto==IPPROTO_TCP)
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// we do not need conntrack entry anymore if all cutoff conditions are either not defined or reached
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// do not drop udp entry because it will be recreated when next packet arrives
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ctrack->b_cutoff |= (!params.wssize || ctrack->b_wssize_cutoff) && (!params.desync_cutoff || ctrack->b_desync_cutoff);
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}
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}
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static void wssize_cutoff(t_ctrack *ctrack)
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{
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if (ctrack)
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{
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ctrack->b_wssize_cutoff = true;
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maybe_cutoff(ctrack, IPPROTO_TCP);
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}
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}
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#define CONNTRACK_REQUIRED (params.wssize || params.desync_cutoff)
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// result : true - drop original packet, false = dont drop
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packet_process_result dpi_desync_tcp_packet(uint32_t fwmark, const char *ifout, uint8_t *data_pkt, size_t len_pkt, struct ip *ip, struct ip6_hdr *ip6hdr, struct tcphdr *tcphdr, size_t len_tcp, uint8_t *data_payload, size_t len_payload)
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{
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packet_process_result res=pass;
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t_ctrack *ctrack=NULL;
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bool bReverse=false;
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struct sockaddr_storage src, dst;
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uint8_t pkt1[DPI_DESYNC_MAX_FAKE_LEN+100], pkt2[DPI_DESYNC_MAX_FAKE_LEN+100];
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size_t pkt1_len, pkt2_len;
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uint8_t ttl_orig,ttl_fake,flags_orig,scale_factor;
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uint32_t *timestamps;
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if (!!ip == !!ip6hdr) return res; // one and only one must be present
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if (CONNTRACK_REQUIRED)
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{
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ConntrackPoolPurge(¶ms.conntrack);
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if (ConntrackPoolFeed(¶ms.conntrack, ip, ip6hdr, tcphdr, NULL, len_payload, &ctrack, &bReverse))
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maybe_cutoff(ctrack, IPPROTO_TCP);
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}
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//ConntrackPoolDump(¶ms.conntrack);
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if (params.wsize && tcp_synack_segment(tcphdr))
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{
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tcp_rewrite_winsize(tcphdr, params.wsize, params.wscale);
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res=modify;
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}
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if (bReverse) return res; // nothing to do. do not waste cpu
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uint32_t desync_fwmark = fwmark | params.desync_fwmark;
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if (params.wssize)
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{
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if (ctrack)
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{
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if (ctrack->b_wssize_cutoff)
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{
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DLOG("not changing wssize. wssize-cutoff reached\n");
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}
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else
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{
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if (params.wssize_cutoff) DLOG("wssize-cutoff not reached (mode %c): %llu/%u\n", params.wssize_cutoff_mode, (unsigned long long)cutoff_get_limit(ctrack,params.wssize_cutoff_mode), params.wssize_cutoff);
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tcp_rewrite_winsize(tcphdr, params.wssize, params.wsscale);
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res=modify;
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}
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}
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else
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{
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DLOG("not changing wssize. wssize is set but conntrack entry is missing\n");
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}
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}
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if (params.desync_mode0!=DESYNC_NONE || params.desync_mode!=DESYNC_NONE) // save some cpu
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{
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ttl_orig = ip ? ip->ip_ttl : ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_hlim;
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if (ip6hdr) ttl_fake = params.desync_ttl6 ? params.desync_ttl6 : ttl_orig;
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else ttl_fake = params.desync_ttl ? params.desync_ttl : ttl_orig;
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flags_orig = *((uint8_t*)tcphdr+13);
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scale_factor = tcp_find_scale_factor(tcphdr);
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timestamps = tcp_find_timestamps(tcphdr);
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extract_endpoints(ip, ip6hdr, tcphdr, NULL, &src, &dst);
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}
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if (params.desync_mode0==DESYNC_SYNACK && tcp_syn_segment(tcphdr))
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{
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pkt1_len = sizeof(pkt1);
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if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, TH_SYN|TH_ACK, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
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ttl_fake,params.desync_fooling_mode,params.desync_badseq_increment,params.desync_badseq_ack_increment,
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NULL, 0, pkt1, &pkt1_len))
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{
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return res;
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}
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DLOG("sending fake SYNACK\n");
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if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
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return res;
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}
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if (params.desync_cutoff)
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{
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if (ctrack)
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{
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if (ctrack->b_desync_cutoff)
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{
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DLOG("not desyncing. desync-cutoff reached (mode %c): %llu/%u\n", params.desync_cutoff_mode, (unsigned long long)cutoff_get_limit(ctrack,params.desync_cutoff_mode), params.desync_cutoff);
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return res;
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}
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DLOG("desync-cutoff not reached (mode %c): %llu/%u\n", params.desync_cutoff_mode, (unsigned long long)cutoff_get_limit(ctrack,params.desync_cutoff_mode), params.desync_cutoff);
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}
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else
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{
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DLOG("not desyncing. desync-cutoff is set but conntrack entry is missing\n");
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return res;
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}
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}
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if (!params.wssize && params.desync_mode==DESYNC_NONE && !params.hostcase && !params.hostnospace && !params.domcase) return res; // nothing to do. do not waste cpu
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if (!(tcphdr->th_flags & TH_SYN) && len_payload)
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{
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const uint8_t *fake;
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size_t fake_size;
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char host[256];
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bool bHaveHost=false;
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bool bIsHttp;
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bool bKnownProtocol = false;
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uint8_t *p, *phost;
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if ((bIsHttp = IsHttp(data_payload,len_payload)))
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{
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DLOG("packet contains HTTP request\n")
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if (params.wssize) DLOG("forced wssize-cutoff\n");
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wssize_cutoff(ctrack);
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fake = params.fake_http;
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fake_size = params.fake_http_size;
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if (params.hostlist || params.debug) bHaveHost=HttpExtractHost(data_payload,len_payload,host,sizeof(host));
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if (params.hostlist && !bHaveHost)
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{
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DLOG("not applying tampering to HTTP without Host:\n")
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return res;
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}
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bKnownProtocol = true;
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}
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else if (IsTLSClientHello(data_payload,len_payload))
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{
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DLOG("packet contains TLS ClientHello\n")
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if (params.wssize) DLOG("forced wssize-cutoff\n");
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wssize_cutoff(ctrack);
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fake = params.fake_tls;
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fake_size = params.fake_tls_size;
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if (params.hostlist || params.desync_skip_nosni || params.debug)
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{
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bHaveHost=TLSHelloExtractHost(data_payload,len_payload,host,sizeof(host));
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if (params.desync_skip_nosni && !bHaveHost)
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{
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DLOG("not applying tampering to TLS ClientHello without hostname in the SNI\n")
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return res;
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}
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}
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bKnownProtocol = true;
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}
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else
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{
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if (!params.desync_any_proto) return res;
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DLOG("applying tampering to unknown protocol\n")
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fake = params.fake_unknown;
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fake_size = params.fake_unknown_size;
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}
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if (bHaveHost)
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{
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DLOG("hostname: %s\n",host)
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if ((params.hostlist || params.hostlist_exclude) && !HostlistCheck(params.hostlist, params.hostlist_exclude, host))
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{
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DLOG("not applying tampering to this request\n")
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return res;
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}
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}
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if (bIsHttp && (params.hostcase || params.hostnospace || params.domcase) && (phost = (uint8_t*)memmem(data_payload, len_payload, "\r\nHost: ", 8)))
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{
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|
if (params.hostcase)
|
|
{
|
|
DLOG("modifying Host: => %c%c%c%c:\n", params.hostspell[0], params.hostspell[1], params.hostspell[2], params.hostspell[3])
|
|
memcpy(phost + 2, params.hostspell, 4);
|
|
res=modify;
|
|
}
|
|
if (params.domcase)
|
|
{
|
|
DLOG("mixing domain case\n");
|
|
for (p = phost+7; p < (data_payload + len_payload) && *p != '\r' && *p != '\n'; p++)
|
|
*p = (((size_t)p) & 1) ? tolower(*p) : toupper(*p);
|
|
res=modify;
|
|
}
|
|
uint8_t *pua;
|
|
if (params.hostnospace &&
|
|
(pua = (uint8_t*)memmem(data_payload, len_payload, "\r\nUser-Agent: ", 14)) &&
|
|
(pua = (uint8_t*)memmem(pua + 1, len_payload - (pua - data_payload) - 1, "\r\n", 2)))
|
|
{
|
|
DLOG("removing space after Host: and adding it to User-Agent:\n")
|
|
if (pua > phost)
|
|
{
|
|
memmove(phost + 7, phost + 8, pua - phost - 8);
|
|
phost[pua - phost - 1] = ' ';
|
|
}
|
|
else
|
|
{
|
|
memmove(pua + 1, pua, phost - pua + 7);
|
|
*pua = ' ';
|
|
}
|
|
res=modify;
|
|
}
|
|
}
|
|
|
|
if (params.desync_mode==DESYNC_NONE) return res;
|
|
|
|
if (params.debug)
|
|
{
|
|
printf("dpi desync src=");
|
|
print_sockaddr((struct sockaddr *)&src);
|
|
printf(" dst=");
|
|
print_sockaddr((struct sockaddr *)&dst);
|
|
printf("\n");
|
|
}
|
|
|
|
enum dpi_desync_mode desync_mode = params.desync_mode;
|
|
uint8_t fooling_orig = FOOL_NONE;
|
|
bool b;
|
|
|
|
pkt1_len = sizeof(pkt1);
|
|
b = false;
|
|
switch(desync_mode)
|
|
{
|
|
case DESYNC_FAKE_KNOWN:
|
|
if (!bKnownProtocol)
|
|
{
|
|
DLOG("not applying fake because of unknown protocol\n");
|
|
desync_mode = params.desync_mode2;
|
|
break;
|
|
}
|
|
case DESYNC_FAKE:
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_fake,params.desync_fooling_mode,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
fake, fake_size, pkt1, &pkt1_len))
|
|
{
|
|
return res;
|
|
}
|
|
DLOG("sending fake request : ");
|
|
hexdump_limited_dlog(fake,fake_size,PKTDATA_MAXDUMP); DLOG("\n")
|
|
b = true;
|
|
break;
|
|
case DESYNC_RST:
|
|
case DESYNC_RSTACK:
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, TH_RST | (desync_mode==DESYNC_RSTACK ? TH_ACK:0), tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_fake,params.desync_fooling_mode,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
NULL, 0, pkt1, &pkt1_len))
|
|
{
|
|
return res;
|
|
}
|
|
DLOG("sending fake RST/RSTACK\n");
|
|
b = true;
|
|
break;
|
|
case DESYNC_HOPBYHOP:
|
|
case DESYNC_DESTOPT:
|
|
case DESYNC_IPFRAG1:
|
|
fooling_orig = (desync_mode==DESYNC_HOPBYHOP) ? FOOL_HOPBYHOP : (desync_mode==DESYNC_DESTOPT) ? FOOL_DESTOPT : FOOL_IPFRAG1;
|
|
if (ip6hdr && (params.desync_mode2==DESYNC_NONE || !desync_valid_second_stage_tcp(params.desync_mode2)))
|
|
{
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_orig,fooling_orig,0,0,
|
|
data_payload, len_payload, pkt1, &pkt1_len))
|
|
{
|
|
return res;
|
|
}
|
|
DLOG("resending original packet with extension header\n");
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
// this mode is final, no other options available
|
|
return drop;
|
|
}
|
|
desync_mode = params.desync_mode2;
|
|
}
|
|
|
|
if (b)
|
|
{
|
|
if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
if (params.desync_mode2==DESYNC_NONE || !desync_valid_second_stage_tcp(params.desync_mode2))
|
|
{
|
|
if (params.desync_retrans)
|
|
{
|
|
DLOG("dropping original packet to force retransmission. len=%zu len_payload=%zu\n", len_pkt, len_payload)
|
|
}
|
|
else
|
|
{
|
|
DLOG("reinjecting original packet. len=%zu len_payload=%zu\n", len_pkt, len_payload)
|
|
#ifdef __FreeBSD__
|
|
// FreeBSD tend to pass ipv6 frames with wrong checksum
|
|
if (res==modify || ip6hdr)
|
|
#else
|
|
// if original packet was tampered earlier it needs checksum fixed
|
|
if (res==modify)
|
|
#endif
|
|
tcp_fix_checksum(tcphdr,len_tcp,ip,ip6hdr);
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , data_pkt, len_pkt))
|
|
return res;
|
|
}
|
|
return drop;
|
|
}
|
|
desync_mode = params.desync_mode2;
|
|
}
|
|
|
|
size_t split_pos=len_payload>params.desync_split_pos ? params.desync_split_pos : 1;
|
|
pkt1_len = sizeof(pkt1);
|
|
switch(desync_mode)
|
|
{
|
|
case DESYNC_DISORDER:
|
|
case DESYNC_DISORDER2:
|
|
{
|
|
uint8_t fakeseg[DPI_DESYNC_MAX_FAKE_LEN+100];
|
|
size_t fakeseg_len;
|
|
|
|
if (split_pos<len_payload)
|
|
{
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(tcphdr->th_seq,split_pos), tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_orig,fooling_orig,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
data_payload+split_pos, len_payload-split_pos, pkt1, &pkt1_len))
|
|
return res;
|
|
DLOG("sending 2nd out-of-order tcp segment %zu-%zu len=%zu : ",split_pos,len_payload-1, len_payload-split_pos)
|
|
hexdump_limited_dlog(data_payload+split_pos,len_payload-split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
}
|
|
|
|
|
|
if (desync_mode==DESYNC_DISORDER)
|
|
{
|
|
fakeseg_len = sizeof(fakeseg);
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_fake,params.desync_fooling_mode,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
zeropkt, split_pos, fakeseg, &fakeseg_len))
|
|
return res;
|
|
DLOG("sending fake(1) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos)
|
|
hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
|
|
return res;
|
|
}
|
|
|
|
|
|
pkt1_len = sizeof(pkt1);
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_orig,fooling_orig,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
data_payload, split_pos, pkt1, &pkt1_len))
|
|
return res;
|
|
DLOG("sending 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos)
|
|
hexdump_limited_dlog(data_payload,split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
|
|
if (desync_mode==DESYNC_DISORDER)
|
|
{
|
|
DLOG("sending fake(2) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos)
|
|
hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
|
|
return res;
|
|
}
|
|
|
|
return drop;
|
|
}
|
|
break;
|
|
case DESYNC_SPLIT:
|
|
case DESYNC_SPLIT2:
|
|
{
|
|
uint8_t fakeseg[DPI_DESYNC_MAX_FAKE_LEN+100];
|
|
size_t fakeseg_len;
|
|
|
|
if (desync_mode==DESYNC_SPLIT)
|
|
{
|
|
fakeseg_len = sizeof(fakeseg);
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_fake,params.desync_fooling_mode,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
zeropkt, split_pos, fakeseg, &fakeseg_len))
|
|
return res;
|
|
DLOG("sending fake(1) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos)
|
|
hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
|
|
return res;
|
|
}
|
|
|
|
pkt1_len = sizeof(pkt1);
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, tcphdr->th_seq, tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_orig,fooling_orig,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
data_payload, split_pos, pkt1, &pkt1_len))
|
|
return res;
|
|
DLOG("sending 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos)
|
|
hexdump_limited_dlog(data_payload,split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
|
|
if (desync_mode==DESYNC_SPLIT)
|
|
{
|
|
DLOG("sending fake(2) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos)
|
|
hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
|
|
return res;
|
|
}
|
|
|
|
if (split_pos<len_payload)
|
|
{
|
|
pkt1_len = sizeof(pkt1);
|
|
if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(tcphdr->th_seq,split_pos), tcphdr->th_ack, tcphdr->th_win, scale_factor, timestamps,
|
|
ttl_orig,fooling_orig,params.desync_badseq_increment,params.desync_badseq_ack_increment,
|
|
data_payload+split_pos, len_payload-split_pos, pkt1, &pkt1_len))
|
|
return res;
|
|
DLOG("sending 2nd tcp segment %zu-%zu len=%zu : ",split_pos,len_payload-1, len_payload-split_pos)
|
|
hexdump_limited_dlog(data_payload+split_pos,len_payload-split_pos,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
}
|
|
|
|
return drop;
|
|
}
|
|
break;
|
|
case DESYNC_IPFRAG2:
|
|
{
|
|
#ifdef __FreeBSD__
|
|
// FreeBSD tend to pass ipv6 frames with wrong checksum
|
|
if (res==modify || ip6hdr)
|
|
#else
|
|
// if original packet was tampered earlier it needs checksum fixed
|
|
if (res==modify)
|
|
#endif
|
|
tcp_fix_checksum(tcphdr,len_tcp,ip,ip6hdr);
|
|
|
|
uint8_t pkt3[DPI_DESYNC_MAX_FAKE_LEN+100], *pkt_orig;
|
|
size_t pkt_orig_len;
|
|
|
|
size_t ipfrag_pos = (params.desync_ipfrag_pos_tcp && params.desync_ipfrag_pos_tcp<len_tcp) ? params.desync_ipfrag_pos_tcp : 24;
|
|
uint32_t ident = ip ? ip->ip_id ? ip->ip_id : htons(1+random()%0xFFFF) : htonl(1+random()%0xFFFFFFFF);
|
|
|
|
pkt1_len = sizeof(pkt1);
|
|
pkt2_len = sizeof(pkt2);
|
|
|
|
if (ip6hdr && (fooling_orig==FOOL_HOPBYHOP || fooling_orig==FOOL_DESTOPT))
|
|
{
|
|
pkt_orig_len = sizeof(pkt3);
|
|
if (!ip6_insert_simple_hdr(fooling_orig==FOOL_HOPBYHOP ? IPPROTO_HOPOPTS : IPPROTO_DSTOPTS, data_pkt, len_pkt, pkt3, &pkt_orig_len))
|
|
return res;
|
|
pkt_orig = pkt3;
|
|
}
|
|
else
|
|
{
|
|
pkt_orig = data_pkt;
|
|
pkt_orig_len = len_pkt;
|
|
}
|
|
|
|
if (!ip_frag(pkt_orig, pkt_orig_len, ipfrag_pos, ident, pkt1, &pkt1_len, pkt2, &pkt2_len))
|
|
return res;
|
|
|
|
DLOG("sending 1st ip fragment 0-%zu len=%zu : ", ipfrag_pos-1, ipfrag_pos)
|
|
hexdump_limited_dlog(pkt1,pkt1_len,IP_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt2, pkt2_len))
|
|
return res;
|
|
|
|
DLOG("sending 2nd ip fragment %zu-%zu len=%zu : ", ipfrag_pos, len_tcp-1, len_tcp-ipfrag_pos)
|
|
hexdump_limited_dlog(pkt2,pkt2_len,IP_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
|
|
return frag;
|
|
}
|
|
}
|
|
}
|
|
|
|
return res;
|
|
}
|
|
|
|
|
|
|
|
packet_process_result dpi_desync_udp_packet(uint32_t fwmark, const char *ifout, uint8_t *data_pkt, size_t len_pkt, struct ip *ip, struct ip6_hdr *ip6hdr, struct udphdr *udphdr, uint8_t *data_payload, size_t len_payload)
|
|
{
|
|
packet_process_result res=pass;
|
|
t_ctrack *ctrack=NULL;
|
|
bool bReverse=false;
|
|
|
|
struct sockaddr_storage src, dst;
|
|
uint8_t pkt1[DPI_DESYNC_MAX_FAKE_LEN+100], pkt2[DPI_DESYNC_MAX_FAKE_LEN+100];
|
|
size_t pkt1_len, pkt2_len;
|
|
uint8_t ttl_orig,ttl_fake;
|
|
|
|
if (!!ip == !!ip6hdr) return res; // one and only one must be present
|
|
|
|
if (CONNTRACK_REQUIRED)
|
|
{
|
|
ConntrackPoolPurge(¶ms.conntrack);
|
|
if (ConntrackPoolFeed(¶ms.conntrack, ip, ip6hdr, NULL, udphdr, len_payload, &ctrack, &bReverse))
|
|
maybe_cutoff(ctrack, IPPROTO_UDP);
|
|
}
|
|
|
|
//ConntrackPoolDump(¶ms.conntrack);
|
|
|
|
if (bReverse) return res; // nothing to do. do not waste cpu
|
|
|
|
if (params.desync_cutoff)
|
|
{
|
|
if (ctrack)
|
|
{
|
|
if (ctrack->b_desync_cutoff)
|
|
{
|
|
DLOG("not desyncing. desync-cutoff reached (mode %c): %llu/%u\n", params.desync_cutoff_mode, (unsigned long long)cutoff_get_limit(ctrack,params.desync_cutoff_mode), params.desync_cutoff);
|
|
return res;
|
|
}
|
|
DLOG("desync-cutoff not reached (mode %c): %llu/%u\n", params.desync_cutoff_mode, (unsigned long long)cutoff_get_limit(ctrack,params.desync_cutoff_mode), params.desync_cutoff);
|
|
}
|
|
else
|
|
{
|
|
DLOG("not desyncing. desync-cutoff is set but conntrack entry is missing\n");
|
|
return res;
|
|
}
|
|
}
|
|
|
|
if (params.desync_mode==DESYNC_NONE) return res;
|
|
|
|
if (len_payload)
|
|
{
|
|
const uint8_t *fake;
|
|
size_t fake_size;
|
|
bool b;
|
|
char host[256];
|
|
bool bHaveHost=false;
|
|
bool bKnownProtocol=false;
|
|
|
|
if (IsQUICInitial(data_payload,len_payload))
|
|
{
|
|
DLOG("packet contains QUIC initial\n")
|
|
fake = params.fake_quic;
|
|
fake_size = params.fake_quic_size;
|
|
|
|
bool bIsCryptoHello, bDecryptOK;
|
|
bHaveHost=QUICExtractHostFromInitial(data_payload,len_payload,host,sizeof(host), &bDecryptOK,&bIsCryptoHello);
|
|
if (bIsCryptoHello)
|
|
{
|
|
// decrypted and payload is ClientHello
|
|
if (params.desync_skip_nosni && !bHaveHost)
|
|
{
|
|
DLOG("not applying tampering to QUIC ClientHello without hostname in the SNI\n")
|
|
return res;
|
|
}
|
|
}
|
|
else if (!bDecryptOK)
|
|
{
|
|
// could not decrypt
|
|
if (params.desync_skip_nosni)
|
|
{
|
|
DLOG("not applying tampering to QUIC initial that could not be decrypted\n")
|
|
return res;
|
|
}
|
|
else
|
|
// consider this case the same way as absence of the SNI. DPI also might not be able to decrypt this and get SNI
|
|
DLOG("QUIC initial decryption failed. still applying tampering because desync_skip_nosni is not set\n")
|
|
}
|
|
else
|
|
{
|
|
// decrypted and payload is not ClientHello
|
|
if (params.desync_any_proto)
|
|
{
|
|
DLOG("QUIC initial without CRYPTO frame. applying tampering because desync_any_proto is set\n")
|
|
}
|
|
else
|
|
{
|
|
DLOG("not applying tampering to QUIC initial without CRYPTO frame\n")
|
|
return res;
|
|
}
|
|
}
|
|
bKnownProtocol = true;
|
|
}
|
|
else
|
|
{
|
|
if (!params.desync_any_proto) return res;
|
|
DLOG("applying tampering to unknown protocol\n")
|
|
fake = params.fake_unknown_udp;
|
|
fake_size = params.fake_unknown_udp_size;
|
|
}
|
|
|
|
if (bHaveHost)
|
|
{
|
|
DLOG("hostname: %s\n",host)
|
|
if ((params.hostlist || params.hostlist_exclude) && !HostlistCheck(params.hostlist, params.hostlist_exclude, host))
|
|
{
|
|
DLOG("not applying tampering to this request\n")
|
|
return res;
|
|
}
|
|
}
|
|
|
|
enum dpi_desync_mode desync_mode = params.desync_mode;
|
|
uint8_t fooling_orig = FOOL_NONE;
|
|
|
|
ttl_orig = ip ? ip->ip_ttl : ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_hlim;
|
|
if (ip6hdr) ttl_fake = params.desync_ttl6 ? params.desync_ttl6 : ttl_orig;
|
|
else ttl_fake = params.desync_ttl ? params.desync_ttl : ttl_orig;
|
|
extract_endpoints(ip, ip6hdr, NULL, udphdr, &src, &dst);
|
|
|
|
if (params.debug)
|
|
{
|
|
printf("dpi desync src=");
|
|
print_sockaddr((struct sockaddr *)&src);
|
|
printf(" dst=");
|
|
print_sockaddr((struct sockaddr *)&dst);
|
|
printf("\n");
|
|
}
|
|
|
|
uint32_t desync_fwmark = fwmark | params.desync_fwmark;
|
|
|
|
pkt1_len = sizeof(pkt1);
|
|
b = false;
|
|
switch(desync_mode)
|
|
{
|
|
case DESYNC_FAKE_KNOWN:
|
|
if (!bKnownProtocol)
|
|
{
|
|
DLOG("not applying fake because of unknown protocol\n");
|
|
desync_mode = params.desync_mode2;
|
|
break;
|
|
}
|
|
case DESYNC_FAKE:
|
|
if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_fake, params.desync_fooling_mode, 0, fake, fake_size, pkt1, &pkt1_len))
|
|
return res;
|
|
DLOG("sending fake request : ");
|
|
hexdump_limited_dlog(fake,fake_size,PKTDATA_MAXDUMP); DLOG("\n")
|
|
if (!rawsend_rep((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
b = true;
|
|
break;
|
|
case DESYNC_HOPBYHOP:
|
|
case DESYNC_DESTOPT:
|
|
case DESYNC_IPFRAG1:
|
|
fooling_orig = (desync_mode==DESYNC_HOPBYHOP) ? FOOL_HOPBYHOP : (desync_mode==DESYNC_DESTOPT) ? FOOL_DESTOPT : FOOL_IPFRAG1;
|
|
if (ip6hdr && (params.desync_mode2==DESYNC_NONE || !desync_valid_second_stage_udp(params.desync_mode2)))
|
|
{
|
|
if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst,
|
|
ttl_orig,fooling_orig,0,
|
|
data_payload, len_payload, pkt1, &pkt1_len))
|
|
{
|
|
return res;
|
|
}
|
|
DLOG("resending original packet with extension header\n");
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
// this mode is final, no other options available
|
|
return drop;
|
|
}
|
|
desync_mode = params.desync_mode2;
|
|
break;
|
|
}
|
|
|
|
if (b)
|
|
{
|
|
if (params.desync_mode2==DESYNC_NONE || !desync_valid_second_stage_udp(params.desync_mode2))
|
|
{
|
|
DLOG("reinjecting original packet. len=%zu len_payload=%zu\n", len_pkt, len_payload)
|
|
#ifdef __FreeBSD__
|
|
// FreeBSD tend to pass ipv6 frames with wrong checksum
|
|
if (res==modify || ip6hdr)
|
|
#else
|
|
// if original packet was tampered earlier it needs checksum fixed
|
|
if (res==modify)
|
|
#endif
|
|
udp_fix_checksum(udphdr,sizeof(struct udphdr)+len_payload,ip,ip6hdr);
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , data_pkt, len_pkt))
|
|
return res;
|
|
return drop;
|
|
}
|
|
desync_mode = params.desync_mode2;
|
|
}
|
|
|
|
switch(desync_mode)
|
|
{
|
|
case DESYNC_UDPLEN:
|
|
pkt1_len = sizeof(pkt1);
|
|
if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,fooling_orig, params.udplen_increment, data_payload, len_payload, pkt1, &pkt1_len))
|
|
{
|
|
DLOG("could not construct packet with modified length. too large ?\n");
|
|
return res;
|
|
}
|
|
DLOG("resending original packet with increased by %d length\n", params.udplen_increment);
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
return drop;
|
|
case DESYNC_IPFRAG2:
|
|
{
|
|
|
|
#ifdef __FreeBSD__
|
|
// FreeBSD tend to pass ipv6 frames with wrong checksum
|
|
if (res==modify || ip6hdr)
|
|
#else
|
|
// if original packet was tampered earlier it needs checksum fixed
|
|
if (res==modify)
|
|
#endif
|
|
udp_fix_checksum(udphdr,sizeof(struct udphdr)+len_payload,ip,ip6hdr);
|
|
|
|
uint8_t pkt3[DPI_DESYNC_MAX_FAKE_LEN+100], *pkt_orig;
|
|
size_t pkt_orig_len;
|
|
|
|
size_t len_transport = len_payload + sizeof(struct udphdr);
|
|
size_t ipfrag_pos = (params.desync_ipfrag_pos_udp && params.desync_ipfrag_pos_udp<len_transport) ? params.desync_ipfrag_pos_udp : sizeof(struct udphdr);
|
|
// freebsd do not set ip.id
|
|
uint32_t ident = ip ? ip->ip_id ? ip->ip_id : htons(1+random()%0xFFFF) : htonl(1+random()%0xFFFFFFFF);
|
|
|
|
pkt1_len = sizeof(pkt1);
|
|
pkt2_len = sizeof(pkt2);
|
|
|
|
if (ip6hdr && (fooling_orig==FOOL_HOPBYHOP || fooling_orig==FOOL_DESTOPT))
|
|
{
|
|
pkt_orig_len = sizeof(pkt3);
|
|
if (!ip6_insert_simple_hdr(fooling_orig==FOOL_HOPBYHOP ? IPPROTO_HOPOPTS : IPPROTO_DSTOPTS, data_pkt, len_pkt, pkt3, &pkt_orig_len))
|
|
return res;
|
|
pkt_orig = pkt3;
|
|
}
|
|
else
|
|
{
|
|
pkt_orig = data_pkt;
|
|
pkt_orig_len = len_pkt;
|
|
}
|
|
|
|
if (!ip_frag(pkt_orig, pkt_orig_len, ipfrag_pos, ident, pkt1, &pkt1_len, pkt2, &pkt2_len))
|
|
return res;
|
|
|
|
DLOG("sending 1st ip fragment 0-%zu len=%zu : ", ipfrag_pos-1, ipfrag_pos)
|
|
hexdump_limited_dlog(pkt1,pkt1_len,IP_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt2, pkt2_len))
|
|
return res;
|
|
|
|
DLOG("sending 2nd ip fragment %zu-%zu len=%zu : ", ipfrag_pos, len_transport-1, len_transport-ipfrag_pos)
|
|
hexdump_limited_dlog(pkt2,pkt2_len,IP_MAXDUMP); DLOG("\n")
|
|
if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
|
|
return res;
|
|
|
|
return frag;
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
return res;
|
|
}
|