libt2n: (gerd) add hello peek

diff --git a/src/command_client.cpp b/src/command_client.cpp
index 77daf0d..376d3f9 100644 (file)
--- a/src/command_client.cpp
+++ b/src/command_client.cpp
@@ -67,30 +67,97 @@ std::string command_client::read_packet(const long long &usec_timeout)
 
 void command_client::read_hello()
 {
-    istringstream hello(read_packet(hello_timeout_usec));
+    string resultpacket;
+    bool got_packet=false;
+    long long my_timeout=hello_timeout_usec;
+    while(!(got_packet=c.get_packet(resultpacket)) && my_timeout > 0  && !c.is_closed())
+    {
+        c.fill_buffer(my_timeout,&my_timeout);
+
+        c.peek_packet(resultpacket);
+        check_hello(resultpacket);           // will throw before timeout if wrong data received
+    }
+
+    if (!got_packet)
+        throw t2n_transfer_error("timeout exceeded");
+
+    if (!check_hello(resultpacket))
+        throw t2n_version_mismatch("illegal hello received (incomplete): "+resultpacket);
+}
+
+bool command_client::check_hello(const string& hellostr)
+{
+    istringstream hello(hellostr);
 
-    char chk[5];
-    hello.read(chk,4);
-    chk[4]=0;
-    if (hello.fail() || hello.eof() || string("T2Nv") != chk)
-        throw t2n_version_mismatch("illegal hello received (T2N)");
+    char chk;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != 'T')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != '2')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != 'N')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != 'v')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
 
     int prot_version;
-    hello >> prot_version;
-    if (hello.fail() || hello.eof() || prot_version != PROTOCOL_VERSION)
-        throw t2n_version_mismatch("not compatible with the server protocol version");
+    if (hello >> prot_version)
+    {
+        if (prot_version != PROTOCOL_VERSION)
+            throw t2n_version_mismatch("not compatible with the server protocol version");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != ';')
+            throw t2n_version_mismatch("illegal hello received (1. ;)");
+    }
+    else
+        return false;
 
-    hello.read(chk,1);
-    if (hello.fail() || hello.eof() || chk[0] != ';')
-        throw t2n_version_mismatch("illegal hello received (1. ;)");
+    unsigned int hbo;
+    if (hello.read((char*)&hbo,sizeof(hbo)))
+    {
+        if (hbo != 1)
+            throw t2n_version_mismatch("host byte order not matching");
+    }
+    else
+        return false;
 
-    hello.read(chk,4);
-    if (hello.fail() || hello.eof() || *((int*)chk) != 1)
-        throw t2n_version_mismatch("host byte order not matching");
+    if (hello.read(&chk,1))
+    {
+        if (chk != ';')
+            throw t2n_version_mismatch("illegal hello received (2. ;)");
+    }
+    else
+        return false;
 
-    hello.read(chk,1);
-    if (hello.fail() || hello.eof() || chk[0] != ';')
-        throw t2n_version_mismatch("illegal hello received (2. ;)");
+    return true;
 }
 
 void command_client::send_command(command* cmd, result_container &res)

diff --git a/src/command_client.hxx b/src/command_client.hxx
index 8c6b2bf..6ec6a1d 100644 (file)
--- a/src/command_client.hxx
+++ b/src/command_client.hxx
@@ -36,6 +36,7 @@ class command_client
 
         void read_hello();
         std::string read_packet(const long long &usec_timeout);
+        bool check_hello(const std::string& hellostr);
 
     public:
         command_client(client_connection& _c, long long _command_timeout_usec=90000000, long long _hello_timeout_usec=30000000);

diff --git a/src/connection.cpp b/src/connection.cpp
index 9cffb89..d339f9f 100644 (file)
--- a/src/connection.cpp
+++ b/src/connection.cpp
@@ -30,8 +30,6 @@ namespace libt2n
 
 connection::packet_size_indicator connection::bytes_available()
 {
-    // max packet size is unsigned int
-
     // no size information -> no packet
     if (buffer.size() < sizeof(packet_size_indicator))
         return 0;
@@ -65,6 +63,29 @@ bool connection::get_packet(std::string& data)
         return false;
 }
 
+/** @brief get (maybe incomplete) data of the next packet from the buffer. Does not remove the data
+            from the connection buffer.
+    @param[out] data the data package
+    @retval full size of the packet when it will be complete
+*/
+unsigned int connection::peek_packet(std::string& data)
+{
+    // no size information -> no packet
+    if (buffer.size() < sizeof(packet_size_indicator))
+        return 0;
+
+    packet_size_indicator psize=ntohl(*((packet_size_indicator*)(buffer.data())));
+
+    // not the full data available?
+    packet_size_indicator currsize=psize;
+    if (buffer.size() < currsize+sizeof(packet_size_indicator))
+        currsize=buffer.size()-sizeof(packet_size_indicator);
+
+    data.assign(buffer,sizeof(packet_size_indicator),currsize);
+
+    return psize;
+}
+
 /// send a blob to the peer
 void connection::write(const std::string& data)
 {

diff --git a/src/connection.hxx b/src/connection.hxx
index 94c3123..60ea862 100644 (file)
--- a/src/connection.hxx
+++ b/src/connection.hxx
@@ -74,6 +74,8 @@ class connection
 
         bool get_packet(std::string& data);
 
+        unsigned int peek_packet(std::string& data);
+
         /// returns true if a complete data packet is in the buffer. retrieve it with get_packet().
         bool packet_available()
             { return bytes_available(); }