Additional retval+errno handling

ext/lwipopts.h

@@ -130,7 +130,7 @@
  * MEMP_NUM_RAW_PCB: Number of raw connection PCBs
  * (requires the LWIP_RAW option)
  */
-#define MEMP_NUM_RAW_PCB                32
+#define MEMP_NUM_RAW_PCB                128
 
 /**
  * MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One

make-netcon.mk

@@ -1,29 +0,0 @@
-SHCC=gcc
-
-# intercept-specific
-intercept_CFLAGS = -c -fPIC -g -O2 -Wall -std=c99 -D_GNU_SOURCE -DNETCON_INTERCEPT
-LIB_NAME = intercept
-SHLIB_EXT=dylib
-SHLIB_MAJOR = 1
-SHLIB_MINOR = 8
-COMMON = common
-OBJS= netcon/intercept.o
-SHLIB = ${LIB_NAME}.${SHLIB_EXT}.${SHLIB_MAJOR}.${SHLIB_MINOR}
-SHLDFLAGS = -g -O2 -Wall -I. -nostdlib -shared
-LIBS = -ldl -lc -lrt -lpthread
-
-lib:
-	${SHCC} $(intercept_CFLAGS) -I. netcon/intercept.c -o netcon/intercept.o
-	${SHCC} $(intercept_CFLAGS) -I. netcon/common.c -o netcon/common.o
-	${SHCC} $(intercept_CFLAGS) -I. netcon/sendfd.c -o netcon/sendfd.o
-	${SHCC} $(SHLDFLAGS) netcon/intercept.o netcon/common.o netcon/sendfd.o -o netcon/libintercept.so.1.0 $(LIBS)
-
-install:
-	cp netcon/libintercept.so.1.0 /lib/libintercept.so.1.0
-	ln -sf /lib/libintercept.so.1.0 /lib/libintercept
-	/usr/bin/install -c netcon/intercept /usr/bin
-
-uninstall:
-	rm -r /lib/libintercept.so.1.0
-	rm -r /lib/libintercept
-	rm -r /usr/bin/intercept

netcon/NetconEthernetTap.cpp

@@ -446,21 +446,29 @@ void NetconEthernetTap::phyOnUnixData(PhySocket *sock,void **uptr,void *data,uns
  * Send a return value to the client for an RPC
  */
 int NetconEthernetTap::send_return_value(TcpConnection *conn, int retval, int _errno = 0)
+{
+	if(conn) {
+		int n = send_return_value(_phy.getDescriptor(conn->rpcSock), retval, _errno);
+		if(n > 0)
+			conn->pending = false;
+		else {
+			fprintf(stderr, "Unable to send return value to the intercept. Closing connection\n");
+			closeConnection(conn);
+		}
+		return n;
+	}
+	return -1;
+}
+
+int NetconEthernetTap::send_return_value(int fd, int retval, int _errno = 0)
 {
 	int sz = sizeof(char) + sizeof(retval) + sizeof(errno);
-  char retmsg[sz];
-  memset(&retmsg, '\0', sizeof(retmsg));
-  retmsg[0]=RPC_RETVAL;
+	char retmsg[sz];
+	memset(&retmsg, '\0', sizeof(retmsg));
+	retmsg[0]=RPC_RETVAL;
 	memcpy(&retmsg[1], &retval, sizeof(retval));
 	memcpy(&retmsg[1]+sizeof(retval), &_errno, sizeof(_errno));
-	int n = write(_phy.getDescriptor(conn->rpcSock), &retmsg, sz);
-  if(n > 0)
-    conn->pending = false;
-  else {
-    fprintf(stderr, "Unable to send return value to the intercept. Closing connection\n");
-		closeConnection(conn);
-  }
-  return n;
+	return write(fd, &retmsg, sz);
 }
 
 /*------------------------------------------------------------------------------
@@ -484,6 +492,24 @@ int NetconEthernetTap::send_return_value(TcpConnection *conn, int retval, int _e
  * @param newly allocated PCB
  * @param error code
  * @return ERR_OK if everything is ok, -1 otherwise
+
+	[ ] EAGAIN or EWOULDBLOCK - The socket is marked nonblocking and no connections are present
+													to be accepted. POSIX.1-2001 allows either error to be returned for
+													this case, and does not require these constants to have the same value,
+													so a portable application should check for both possibilities.
+	[ ] EBADF - The descriptor is invalid.
+	[?] ECONNABORTED - A connection has been aborted.
+	[ ] EFAULT - The addr argument is not in a writable part of the user address space.
+	[ ] EINTR - The system call was interrupted by a signal that was caught before a valid connection arrived; see signal(7).
+	[ ] EINVAL - Socket is not listening for connections, or addrlen is invalid (e.g., is negative).
+	[ ] EINVAL - (accept4()) invalid value in flags.
+	[ ] EMFILE - The per-process limit of open file descriptors has been reached.
+	[ ] ENFILE - The system limit on the total number of open files has been reached.
+	[ ] ENOBUFS, ENOMEM - Not enough free memory. This often means that the memory allocation is limited by the socket buffer limits, not by the system memory.
+	[ ] ENOTSOCK - The descriptor references a file, not a socket.
+	[ ] EOPNOTSUPP - The referenced socket is not of type SOCK_STREAM.
+	[ ] EPROTO - Protocol error.
+
  *
  */
 err_t NetconEthernetTap::nc_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
@@ -507,11 +533,10 @@ err_t NetconEthernetTap::nc_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
 
 		int send_fd = tap->_phy.getDescriptor(conn->rpcSock);
 
-		int n = write(larg_fd, "z", 1);
+		int n = write(larg_fd, "z", 1); // accept() in library waits for this byte
     if(n > 0) {
 			if(sock_fd_write(send_fd, fds[1]) > 0) {
 				new_tcp_conn->pending = true;
-				fprintf(stderr, "nc_accept(): socketpair = { our=%d, their=%d}\n", fds[0], fds[1]);
 			}
 			else {
 				fprintf(stderr, "nc_accept(%d): unable to send fd to client\n", larg_fd);
@@ -526,7 +551,7 @@ err_t NetconEthernetTap::nc_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
     tap->lwipstack->_tcp_err(newpcb, nc_err);
     tap->lwipstack->_tcp_sent(newpcb, nc_sent);
     tap->lwipstack->_tcp_poll(newpcb, nc_poll, 0.5);
-    tcp_accepted(conn->pcb);
+    tcp_accepted(conn->pcb); // Let lwIP know that it can queue additional incoming connections
 		return ERR_OK;
   }
   else {
@@ -691,8 +716,6 @@ err_t NetconEthernetTap::nc_connected(void *arg, struct tcp_pcb *tpcb, err_t err
  * @param structure containing the data and parameters for this client's RPC
  *
 
-	TODO: set errno appropriately
-
 	[ ]	EACCES - The address is protected, and the user is not the superuser.
 	[X]	EADDRINUSE - The given address is already in use.
 	[X]	EBADF - sockfd is not a valid descriptor.
@@ -718,7 +741,6 @@ void NetconEthernetTap::handle_bind(PhySocket *sock, void **uptr, struct bind_st
   int conn_port = lwipstack->ntohs(connaddr->sin_port);
   ip_addr_t conn_addr;
 	conn_addr.addr = *((u32_t *)_ips[0].rawIpData());
-
 	TcpConnection *conn = getConnectionByTheirFD(bind_rpc->sockfd);
 
   if(conn) {
@@ -738,14 +760,18 @@ void NetconEthernetTap::handle_bind(PhySocket *sock, void **uptr, struct bind_st
 					send_return_value(conn, -1, ENOMEM);
 			}
 			else {
-				send_return_value(conn, ERR_OK, 0); // OK
+				send_return_value(conn, ERR_OK, ERR_OK); // Success
 			}
     }
-    else fprintf(stderr, "handle_bind(): PCB not in CLOSED state. Ignoring BIND request.\n");
-		send_return_value(conn, -1, EINVAL);
+    else {
+			fprintf(stderr, "handle_bind(): PCB not in CLOSED state. Ignoring BIND request.\n");
+			send_return_value(conn, -1, EINVAL);
+		}
   }
-  else fprintf(stderr, "handle_bind(): can't locate connection for PCB\n");
-	send_return_value(conn, -1, EBADF);
+  else {
+		fprintf(stderr, "handle_bind(): can't locate connection for PCB\n");
+		send_return_value(conn, -1, EBADF); // FIXME: This makes no sense
+	}
 }
 
 /*
@@ -754,6 +780,12 @@ void NetconEthernetTap::handle_bind(PhySocket *sock, void **uptr, struct bind_st
  * @param Client that is making the RPC
  * @param structure containing the data and parameters for this client's RPC
  *
+
+  [ ] EADDRINUSE - Another socket is already listening on the same port.
+	[X] EBADF - The argument sockfd is not a valid descriptor.
+	[ ] ENOTSOCK - The argument sockfd is not a socket.
+	[ ] EOPNOTSUPP - The socket is not of a type that supports the listen() operation.
+
  */
 void NetconEthernetTap::handle_listen(PhySocket *sock, void **uptr, struct listen_st *listen_rpc)
 {
@@ -771,13 +803,16 @@ void NetconEthernetTap::handle_listen(PhySocket *sock, void **uptr, struct liste
 			/* we need to wait for the client to send us the fd allocated on their end
 			for this listening socket */
       conn->pending = true;
+			send_return_value(conn, ERR_OK, ERR_OK);
     }
     else {
 			fprintf(stderr, "handle_listen(): unable to allocate memory for new listening PCB\n");
+			send_return_value(conn, -1, ENOMEM); // FIXME: This does not have an equivalent errno value
     }
   }
   else {
     fprintf(stderr, "handle_listen(): can't locate connection for PCB\n");
+		send_return_value(conn, -1, EBADF);
   }
 }
 
@@ -838,13 +873,16 @@ void NetconEthernetTap::handle_socket(PhySocket *sock, void **uptr, struct socke
 	  new_conn->their_fd = fds[1];
 		tcp_connections.push_back(new_conn);
     sock_fd_write(_phy.getDescriptor(sock), fds[1]);
-		//fprintf(stderr, "handle_socket(): socketpair = { our=%d, their=%d}\n", fds[0], fds[1]);
-		/* Once the client tells us what its fd is for the other end,
-		we can then complete the mapping */
+		// Once the client tells us what its fd is for the other end, we can then complete the mapping
     new_conn->pending = true;
   }
   else {
+		int rpc_fd = _phy.getDescriptor(sock);
+		sock_fd_write(rpc_fd, -1); // Send a bad fd, to signal error
     fprintf(stderr, "handle_socket(): Memory not available for new PCB\n");
+		if(send_return_value(rpc_fd, -1, ENOMEM) < 0) {
+			fprintf(stderr, "handle_socket(): Unable to send return value\n");
+		}
   }
 }
 

netcon/NetconEthernetTap.hpp

@@ -112,6 +112,7 @@ private:
 	void handle_write(TcpConnection *conn);
 
 	int send_return_value(TcpConnection *conn, int retval, int _errno);
+	int send_return_value(int fd, int retval, int _errno);
 
 	void phyOnDatagram(PhySocket *sock,void **uptr,const struct sockaddr *from,void *data,unsigned long len);
 	void phyOnTcpConnect(PhySocket *sock,void **uptr,bool success);

netcon/intercept.c

@@ -121,6 +121,8 @@ it conflicts with our overriden symbols for read/write */
 #define BUF_SZ                    1024
 #define SERVICE_CONNECT_ATTEMPTS  30
 
+#define ERR_OK          0
+
 ssize_t sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd);
 
 /* threading */
@@ -535,20 +537,30 @@ int socket(SOCKET_SIG)
   ssize_t size = sock_fd_read(fdret_sock, gmybuf, sizeof(gmybuf), &newfd);
   if(size > 0)
   {
-    dwr("socket(): RXed FD = %d\n", newfd);
     /* send our local-fd number back to service so
      it can complete its mapping table entry */
     memset(cmd, '\0', BUF_SZ);
     cmd[0] = RPC_FD_MAP_COMPLETION;
     memcpy(&cmd[1], &newfd, sizeof(newfd));
-    write(fdret_sock, cmd, BUF_SZ);
-    pthread_mutex_unlock(&lock);
-    return newfd;
+    if(newfd > -1) {
+      int n_write = write(fdret_sock, cmd, BUF_SZ);
+      if(n_write < 0) {
+        dwr("Error writing perceived FD to service.\n");
+        return get_retval();
+      }
+      pthread_mutex_unlock(&lock);
+      errno = ERR_OK;
+      return newfd;
+    }
+    else { // Try to read retval+errno since we RXed a bad fd
+      dwr("Error, service sent bad fd.\n");
+      return get_retval();
+    }
   }
   else {
     dwr("Error while receiving new FD.\n");
     pthread_mutex_unlock(&lock);
-    return -1;
+    return get_retval();
   }
   return realsocket(socket_family, socket_type, protocol);
 #endif
@@ -704,7 +716,7 @@ int bind(BIND_SIG)
   pthread_mutex_lock(&lock);
   write(fdret_sock, cmd, BUF_SZ);
   pthread_mutex_unlock(&lock);
-
+  errno = ERR_OK;
   return get_retval();
 #endif
 }
@@ -769,24 +781,31 @@ int accept(ACCEPT_SIG)
     ssize_t size = sock_fd_read(fdret_sock, gmybuf, sizeof(gmybuf), &new_conn_socket);
     if(size > 0)
     {
-      dwr("accept(): RXed FD = %d\n", new_conn_socket);
       /* Send our local-fd number back to service so it can complete its mapping table */
       memset(cmd, '\0', BUF_SZ);
       cmd[0] = RPC_FD_MAP_COMPLETION;
       memcpy(&cmd[1], &new_conn_socket, sizeof(new_conn_socket));
       pthread_mutex_lock(&lock);
-      write(fdret_sock, cmd, BUF_SZ);
+      int n_write = write(fdret_sock, cmd, BUF_SZ);
+      if(n_write < 0) {
+        dwr("Error sending perceived FD to service. Service might be down.\n");
+        errno = ECONNABORTED;
+        return -1;
+      }
       pthread_mutex_unlock(&lock);
-      return new_conn_socket;
+      errno = ERR_OK;
+      return new_conn_socket; // OK
     }
     else {
-      dwr("Error while receiving new FD.\n");
+      dwr("Error receiving new FD from service. Service might be down.\n");
+      errno = ECONNABORTED;
       return -1;
     }
   }
-  errno = EWOULDBLOCK;
+  dwr("Error reading signal byte from service. Service might be down.\n");
+  //errno = EWOULDBLOCK;
+  errno = ECONNABORTED;
   return -1;
-  /* TODO/FIXME: Set errno */
 #endif
 }
 
@@ -822,9 +841,7 @@ int listen(LISTEN_SIG)
   pthread_mutex_lock(&lock);
   write(fdret_sock,cmd, BUF_SZ);
   pthread_mutex_unlock(&lock);
-
-  return 0;
-  /* FIXME: get real return value (should be 0 / -1) */
-  /* FIXME: Also set errno */
+  errno = ERR_OK;
+  return get_retval();
 #endif
 }