UDP desync support

desync.c

@@ -521,3 +521,39 @@ ssize_t desync(int sfd, char *buffer, size_t bfsize,
     }
     return n;
 }
+
+
+ssize_t desync_udp(int sfd, char *buffer, size_t bfsize,
+        ssize_t n, struct sockaddr *dst, int dp_c)
+{
+    struct desync_params *dp = &params.dp[dp_c];
+    int fa = get_family(dst);
+    
+    if (dp->udp_fake_count != 0) {
+        struct packet pkt;
+        if (dp->fake_data.data) {
+            pkt = dp->fake_data;
+        }
+        else {
+            pkt = fake_udp;
+        }
+
+        int bttl = dp->ttl ? dp->ttl : 8;
+        if (setttl(sfd, bttl, fa) < 0) {
+            return -1;
+        }
+        for (int i = 0; i < dp->udp_fake_count; i++) {
+            ssize_t len = sendto(sfd, pkt.data, 
+                pkt.size, 0, dst, sizeof(struct sockaddr_in6));
+            if (len < 0) {
+                uniperror("send");
+                return -1;
+            }
+        }
+        if (setttl(sfd, params.def_ttl, fa) < 0) {
+            return -1;
+        }
+    }
+    return sendto(sfd, buffer, n, 0, 
+        dst, sizeof(struct sockaddr_in6));
+}

desync.h

@@ -1,5 +1,7 @@
 ssize_t desync(int sfd, char *buffer, size_t bfsize, ssize_t n, ssize_t offset, struct sockaddr *dst, int dp_c);
 
+ssize_t desync_udp(int sfd, char *buffer, size_t bfsize, ssize_t n, struct sockaddr *dst, int dp_c);
+
 struct tcpi {
     uint8_t state;
     uint8_t r[3];

extend.c

@@ -146,11 +146,14 @@ bool check_host(struct mphdr *hosts, struct eval *val)
 
 bool check_proto_tcp(int proto, struct eval *val)
 {
-    if ((proto & IS_HTTP) && 
+    if (proto & IS_TCP) {
+        return 1;
+    }
+    else if ((proto & IS_HTTP) && 
             is_http(val->buff.data, val->buff.size)) {
         return 1;
     }
-    if ((proto & IS_HTTPS) && 
+    else if ((proto & IS_HTTPS) && 
             is_tls_chello(val->buff.data, val->buff.size)) {
         return 1;
     }
@@ -365,6 +368,30 @@ int on_desync(struct poolhd *pool, struct eval *val,
     return on_desync_again(pool, val, buffer, bfsize);
 }
 
+
+ssize_t udp_hook(struct eval *val, 
+        char *buffer, size_t bfsize, ssize_t n, struct sockaddr_ina *dst)
+{
+    if (val->recv_count) {
+        return send(val->fd, buffer, n, 0);
+    }
+    int m = val->attempt;
+    if (!m) for (; m < params.dp_count; m++) {
+        struct desync_params *dp = &params.dp[m];
+        if (!dp->detect && 
+                (!dp->proto || (dp->proto & IS_UDP))) {
+            break;
+        }
+    }
+    if (m >= params.dp_count) {
+        return -1;
+    }
+    val->attempt = m;
+    
+    return desync_udp(val->fd, buffer, bfsize, n, &dst->sa, 0);
+}
+
+
 #ifdef __linux__
 int protect(int conn_fd, const char *path)
 {

extend.h

@@ -7,6 +7,9 @@ int on_tunnel_check(struct poolhd *pool, struct eval *val,
 int on_desync(struct poolhd *pool, struct eval *val,
         char *buffer, size_t bfsize, int out);
 
+ssize_t udp_hook(struct eval *val, 
+        char *buffer, size_t bfsize, ssize_t n, struct sockaddr_ina *dst);
+
 #ifdef __linux__
 int protect(int conn_fd, const char *path);
 #else

main.c

@@ -37,6 +37,9 @@ fake_http = {
 },
 oob_data = { 
     sizeof(oob_char), oob_char
+},
+fake_udp = { 
+    sizeof(udp_data), udp_data
 };
 
 
@@ -80,7 +83,7 @@ const char help_text[] = {
     #ifdef TIMEOUT_SUPPORT
     "    -T, --timeout <sec>       Timeout waiting for response, after which trigger auto\n"
     #endif
-    "    -K, --proto[=t,h]         Protocol whitelist: tls,http\n"
+    "    -K, --proto <t,h,u>       Protocol whitelist: tls,http,udp\n"
     "    -H, --hosts <file|:str>   Hosts whitelist\n"
     "    -s, --split <n[+s]>       Split packet at n\n"
     "                              +s - add SNI offset\n"
@@ -100,6 +103,7 @@ const char help_text[] = {
     "    -e, --oob-data <f|:str>   Set custom OOB data, filename or :string\n"
     "    -M, --mod-http <h,d,r>    Modify HTTP: hcsmix,dcsmix,rmspace\n"
     "    -r, --tlsrec <n[+s]>      Make TLS record at position\n"
+    "    -a, --udp-fake <count>    UDP fake count, default 0\n"
 };
 
 
@@ -124,7 +128,7 @@ const struct option options[] = {
     #ifdef TIMEOUT_SUPPORT
     {"timeout",       1, 0, 'T'},
     #endif
-    {"proto",         2, 0, 'K'},
+    {"proto",         1, 0, 'K'},
     {"hosts",         1, 0, 'H'},
     {"split",         1, 0, 's'},
     {"disorder",      1, 0, 'd'},
@@ -142,6 +146,7 @@ const struct option options[] = {
     {"oob-data",      1, 0, 'e'},
     {"mod-http",      1, 0, 'M'},
     {"tlsrec",        1, 0, 'r'},
+    {"udp-fake",      1, 0, 'a'},
     {"def-ttl",       1, 0, 'g'},
     {"delay",         1, 0, 'w'}, //
     {"not-wait-send", 0, 0, 'W'}, //
@@ -564,10 +569,6 @@ int main(int argc, char **argv)
             break;
             
         case 'K':
-            if (!optarg) {
-                dp->proto |= 0xffffffff;
-                break;
-            }
             end = optarg;
             while (end && !invalid) {
                 switch (*end) {
@@ -577,6 +578,9 @@ int main(int argc, char **argv)
                     case 'h': 
                         dp->proto |= IS_HTTP;
                         break;
+                    case 'u': 
+                        dp->proto |= IS_UDP;
+                        break;
                     default:
                         invalid = 1;
                         continue;
@@ -725,6 +729,14 @@ int main(int argc, char **argv)
             }
             break;
             
+        case 'a':
+            val = strtol(optarg, &end, 0);
+            if (val < 0 || val > INT_MAX || *end)
+                invalid = 1;
+            else
+                dp->udp_fake_count = val;
+            break;
+            
         case 'g':
             val = strtol(optarg, &end, 0);
             if (val <= 0 || val > 255 || *end)

packets.c

@@ -53,6 +53,8 @@ char http_data[43] = {
     "Host: www.wikipedia.org\r\n\r\n"
 };
 
+char udp_data[64] = { 0 };
+
 
 char *strncasestr(char *a, size_t as, char *b, size_t bs)
 {

packets.h

@@ -3,11 +3,12 @@
 #include <stdbool.h>
 #include <sys/types.h>
 
-#define IS_UNKNOWN 0
-#define IS_HTTP 1
-#define IS_HTTPS 2
-//#define IS_QUIC 4
-//#define IS_DNS 8
+#define IS_TCP 1
+#define IS_UDP 2
+#define IS_HTTP 4
+#define IS_HTTPS 8
+//#define IS_QUIC 16
+//#define IS_DNS 32
 
 #define MH_HMIX 1
 #define MH_SPACE 2
@@ -15,6 +16,7 @@
 
 extern char tls_data[517];
 extern char http_data[43];
+extern char udp_data[64];
 
 int change_tls_sni(const char *host, char *buffer, size_t bsize);
 

params.h

@@ -56,6 +56,7 @@ struct desync_params {
     ssize_t ip_options_len;
     char md5sig;
     struct packet fake_data;
+    int udp_fake_count;
     
     int parts_n;
     struct part *parts;
@@ -101,5 +102,6 @@ extern struct params params;
 extern struct packet fake_tls;
 extern struct packet fake_http;
 extern struct packet oob_data;
+extern struct packet fake_udp;
 
 extern char ip_option[1];

proxy.c

@@ -695,7 +695,8 @@ int on_udp_tunnel(struct eval *val, char *buffer, size_t bfsize)
                 }
                 val->pair->in6 = addr.in6;
             }
-            ns = send(val->pair->fd, data + offs, n - offs, 0);
+            ns = udp_hook(val, data + offs, bfsize - offs, n - offs, 
+                (struct sockaddr_ina *)&val->pair->in6);
         }
         else {
             map_fix(&addr, 0);