[iscsi] Don't close when receiving NOP-In

Some iSCSI targets send NOP-In.  Rather than closing the connection
when we receive one, it is more user friendly to log a debug message
and keep the connection open.  Eventually, it would be nice if iPXE
supported replying to NOP-Ins, but we might as well keep the
connection open until the target disconnects us.

Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/net/tcp/iscsi.c b/src/net/tcp/iscsi.c
index 51d09ddc7b6af0194dbf5a02b9d7df115c591b5d..1e6fd1f51d7717c2f8a1701afe7b53581ff8454d 100644 (file)
--- a/src/net/tcp/iscsi.c
+++ b/src/net/tcp/iscsi.c
@@ -109,10 +109,6 @@ FEATURE ( FEATURE_PROTOCOL, "iSCSI", DHCP_EB_FEATURE_ISCSI, 1 );
        __einfo_error ( EINFO_ENOTSUP_TARGET_STATUS )
 #define EINFO_ENOTSUP_TARGET_STATUS \
        __einfo_uniqify ( EINFO_ENOTSUP, 0x04, "Unsupported target status" )
-#define ENOTSUP_NOP_IN \
-       __einfo_error ( EINFO_ENOTSUP_NOP_IN )
-#define EINFO_ENOTSUP_NOP_IN \
-       __einfo_uniqify ( EINFO_ENOTSUP, 0x05, "Unsupported NOP-In received" )
 #define EPERM_INITIATOR_AUTHENTICATION \
        __einfo_error ( EINFO_EPERM_INITIATOR_AUTHENTICATION )
 #define EINFO_EPERM_INITIATOR_AUTHENTICATION \
@@ -620,12 +616,15 @@ static int iscsi_rx_nop_in ( struct iscsi_session *iscsi,
         * sent as ping requests, but we can happily accept NOP-Ins
         * sent merely to update CmdSN.
         */
-       if ( nop_in->ttt != htonl ( ISCSI_TAG_RESERVED ) ) {
-               DBGC ( iscsi, "iSCSI %p received unsupported NOP-In with TTT "
-                      "%08x\n", iscsi, ntohl ( nop_in->ttt ) );
-               return -ENOTSUP_NOP_IN;
-       }
+       if ( nop_in->ttt == htonl ( ISCSI_TAG_RESERVED ) )
+               return 0;
 
+       /* Ignore any other NOP-Ins.  The target may eventually
+        * disconnect us for failing to respond, but this minimises
+        * unnecessary connection closures.
+        */
+       DBGC ( iscsi, "iSCSI %p received unsupported NOP-In with TTT %08x\n",
+              iscsi, ntohl ( nop_in->ttt ) );
        return 0;
 }