Fix incorrect fd indexing in mirror mode

Author: svpcom

src/tx.cpp

@@ -194,16 +194,34 @@ void RawSocketTransmitter::set_mark(uint32_t idx)
         return;
     }
 
-    int fd = sockfds[current_output];
-    uint32_t sockopt = this->fwmark + idx;
+    if (current_output >= 0)
+    {
+        int fd = sockfds[current_output];
+        uint32_t sockopt = fwmark + idx;
+
+        if(setsockopt(fd, SOL_SOCKET, SO_MARK, (const void *)&sockopt , sizeof(sockopt)) !=0)
+        {
+            throw runtime_error(string_format("Unable to set SO_MARK fd(%d)=%u: %s", fd, sockopt, strerror(errno)));
+        }
+
+        return;
+    }
 
-    if(setsockopt(fd, SOL_SOCKET, SO_MARK, (const void *)&sockopt , sizeof(sockopt)) !=0)
+    // Handle mirror mode
+    for(auto it = sockfds.begin(); it != sockfds.end(); it++)
     {
-        throw runtime_error(string_format("Unable to set SO_MARK fd(%d)=%u: %s", fd, sockopt, strerror(errno)));
+        int fd = *it;
+        uint32_t sockopt = fwmark + idx;
+
+        if(setsockopt(fd, SOL_SOCKET, SO_MARK, (const void *)&sockopt , sizeof(sockopt)) !=0)
+        {
+            throw runtime_error(string_format("Unable to set SO_MARK fd(%d)=%u: %s", fd, sockopt, strerror(errno)));
+        }
     }
 }
 
 
+
 RawSocketTransmitter::RawSocketTransmitter(int k, int n, const string &keypair, uint64_t epoch, uint32_t channel_id, uint32_t fec_delay,
                                            vector<tags_item_t> &tags, const vector<string> &wlans, vector<uint8_t> &radiotap_header,
                                            uint8_t frame_type, bool use_qdisc, uint32_t fwmark) : \