VSOCK: short alias names, env var with peer info

CHANGES

@@ -85,6 +85,10 @@ Features:
 	Filan prints target of symlink when appropriate
 	Test: FILANSYMLINK
 
+	VSOCK-LISTEN now generates environment variables SOCAT_PEERADDR,
+	SOCAT_PEERPORT, SOCAT_SOCKADDR, SOCAT_SOCKPORT
+	New address aliases VSOCK, VSOCK-L
+
 Documentation:
 	Fixed typo in doc/socat-tun.html and link in README.
 	Thanks to William Suthers for reporting.
@@ -128,6 +132,9 @@ Testing:
 	not in kernel. test.sh now detects this situation and reacts with
 	warnings.
 
+	VSOCK loopback still does not seem to work even in kernel 5.13, so just
+	issue warning on "No such device".
+
 ####################### V 1.7.4.3:
 
 Corrections:

test.sh

@@ -14736,6 +14736,10 @@ elif [ $rc1 -ne 0 ] && [ "$UNAME" = Linux ] && ! [[ $UNAME_R =~ ^[6-9]\.* ]] &&
     $PRINTF "${YELLOW}works only on Linux from 5.6${NORMAL}\n" $N
     numCANT=$((numCANT+1))
     listCANT="$listCANT $N"
+elif grep -q "No such device" "${te}1"; then
+    $PRINTF "${YELLOW}Loopback does not work${NORMAL}\n" $N
+    numCANT=$((numCANT+1))
+    listCANT="$listCANT $N"
 elif [ $rc1 -ne 0 ]; then
     $PRINTF "$FAILED\n"
     echo "$CMD0 &" >&2

xio-socket.c

@@ -14,6 +14,9 @@
 #include "xio-socket.h"
 #include "xio-named.h"
 #include "xio-unix.h"
+#if WITH_VSOCK
+#include "xio-vsock.h"
+#endif
 #if WITH_IP4
 #include "xio-ip4.h"
 #endif /* WITH_IP4 */
@@ -2069,8 +2072,21 @@ int xiosetsockaddrenv(const char *lr,
 	 xiosetenv(namebuff, valuebuff, 1, NULL);
 	 namebuff[strlen(lr)] = '\0';  ++idx;
       } while (result > 0);
-      break; 
+      break;
 #endif /* WITH_IP6 */
+#if WITH_VSOCK
+   case PF_VSOCK:
+      strcpy(namebuff, lr);
+      do {
+	 result =
+	    xiosetsockaddrenv_vsock(idx, strchr(namebuff, '\0'), XIOSOCKADDRENVLEN-strlen(lr),
+				  valuebuff, XIOSOCKADDRENVLEN,
+				  &sau->vm, proto);
+	 xiosetenv(namebuff, valuebuff, 1, NULL);
+	 namebuff[strlen(lr)] = '\0';  ++idx;
+      } while (result > 0);
+      break; 
+#endif /* WITH_VSOCK */
 #if LATER
    case PF_PACKET:
       result = xiosetsockaddrenv_packet(lr, (void *)sau, proto); break;

xio-vsock.c

@@ -3,7 +3,7 @@
 /* Author: Stefano Garzarella <sgarzare@redhat.com */
 /* Published under the GNU General Public License V.2, see file COPYING */
 
-/* this file contains the source for opening addresses of VSOCK socket type */
+/* This file contains the source for opening addresses of VSOCK socket type */
 
 #include "xiosysincludes.h"
 
@@ -164,4 +164,32 @@ static int xioopen_vsock_listen(int argc, const char *argv[], struct opt *opts,
 }
 
 #endif /* WITH_LISTEN */
+
+/* Returns information that can be used for constructing an environment
+   variable describing the socket address.
+   if idx is 0, this function writes "ADDR" into namebuff and the CID address
+   into valuebuff, and returns 1 (which means that one more info is there).
+   if idx is 1, it writes "PORT" into namebuff and the port number into
+   valuebuff, and returns 0 (no more info)
+   namelen and valuelen contain the max. allowed length of output chars in the
+   respective buffer.
+   on error this function returns -1.
+*/
+int
+xiosetsockaddrenv_vsock(int idx, char *namebuff, size_t namelen,
+		      char *valuebuff, size_t valuelen,
+		      struct sockaddr_vm *sa, int ipproto) {
+   switch (idx) {
+   case 0:
+      strcpy(namebuff, "ADDR");
+      snprintf(valuebuff, valuelen, F_uint32_t, sa->svm_cid);
+      return 1;
+   case 1:
+      strcpy(namebuff, "PORT");
+      snprintf(valuebuff, valuelen, F_uint32_t, sa->svm_port);
+      return 0;
+   }
+   return -1;
+}
+
 #endif /* WITH_VSOCK */

xio-vsock.h

@@ -8,4 +8,8 @@
 extern const struct addrdesc addr_vsock_connect;
 extern const struct addrdesc addr_vsock_listen;
 
+extern int xiosetsockaddrenv_vsock(int idx, char *namebuff, size_t namelen,
+			       char *valuebuff, size_t valuelen,
+			       struct sockaddr_vm *sa, int ipproto);
+
 #endif /* !defined(__xio_vsock_h_included) */

xioopen.c

@@ -308,9 +308,11 @@ const struct addrname addressnames[] = {
    { "unix-sendto",	&xioaddr_unix_sendto },
 #endif
 #if WITH_VSOCK
+   { "vsock",		&addr_vsock_connect },
    { "vsock-connect",	&addr_vsock_connect },
 #endif
 #if WITH_VSOCK && WITH_LISTEN
+   { "vsock-l",		&addr_vsock_listen },
    { "vsock-listen",	&addr_vsock_listen },
 #endif
 #else /* !0 */