OS-4865 lxbrand async socket errors catch programs off guard
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
OS-4213 lxbrand should be able to set TCP_DEFER_ACCEPT after other socket operations

*** 295,313 ****
  
  #define SS_RCVATMARK            0x00001000 /* at mark on input */
  #define SS_OOBPEND              0x00002000 /* OOB pending or present - poll */
  #define SS_HAVEOOBDATA          0x00004000 /* OOB data present */
  #define SS_HADOOBDATA           0x00008000 /* OOB data consumed */
- #define SS_CLOSING              0x00010000 /* in process of closing */
  
  #define SS_FIL_DEFER            0x00020000 /* filter deferred notification */
  #define SS_FILOP_OK             0x00040000 /* socket can attach filters */
  #define SS_FIL_RCV_FLOWCTRL     0x00080000 /* filter asserted rcv flow ctrl */
  #define SS_FIL_SND_FLOWCTRL     0x00100000 /* filter asserted snd flow ctrl */
  #define SS_FIL_STOP             0x00200000 /* no more filter actions */
- 
  #define SS_SODIRECT             0x00400000 /* transport supports sodirect */
  
  #define SS_SENTLASTREADSIG      0x01000000 /* last rx signal has been sent */
  #define SS_SENTLASTWRITESIG     0x02000000 /* last tx signal has been sent */
  
  #define SS_FALLBACK_DRAIN       0x20000000 /* data was/is being drained */
--- 295,314 ----
  
  #define SS_RCVATMARK            0x00001000 /* at mark on input */
  #define SS_OOBPEND              0x00002000 /* OOB pending or present - poll */
  #define SS_HAVEOOBDATA          0x00004000 /* OOB data present */
  #define SS_HADOOBDATA           0x00008000 /* OOB data consumed */
  
+ #define SS_CLOSING              0x00010000 /* in process of closing */
  #define SS_FIL_DEFER            0x00020000 /* filter deferred notification */
  #define SS_FILOP_OK             0x00040000 /* socket can attach filters */
  #define SS_FIL_RCV_FLOWCTRL     0x00080000 /* filter asserted rcv flow ctrl */
+ 
  #define SS_FIL_SND_FLOWCTRL     0x00100000 /* filter asserted snd flow ctrl */
  #define SS_FIL_STOP             0x00200000 /* no more filter actions */
  #define SS_SODIRECT             0x00400000 /* transport supports sodirect */
+ #define SS_FILOP_UNSF           0x00800000 /* block attaching unsafe filters */
  
  #define SS_SENTLASTREADSIG      0x01000000 /* last rx signal has been sent */
  #define SS_SENTLASTWRITESIG     0x02000000 /* last tx signal has been sent */
  
  #define SS_FALLBACK_DRAIN       0x20000000 /* data was/is being drained */
*** 319,329 ****
  #define SS_CANTREBIND   (SS_ISCONNECTED|SS_ISCONNECTING|SS_ISDISCONNECTING|\
                              SS_CANTSENDMORE|SS_CANTRCVMORE|SS_ACCEPTCONN)
  
  /*
   * Sockets that can fall back to TPI must ensure that fall back is not
!  * initiated while a thread is using a socket.
   */
  #define SO_BLOCK_FALLBACK(so, fn)                               \
          ASSERT(MUTEX_NOT_HELD(&(so)->so_lock));                 \
          rw_enter(&(so)->so_fallback_rwlock, RW_READER);         \
          if ((so)->so_state & (SS_FALLBACK_COMP|SS_FILOP_OK)) {  \
--- 320,331 ----
  #define SS_CANTREBIND   (SS_ISCONNECTED|SS_ISCONNECTING|SS_ISDISCONNECTING|\
                              SS_CANTSENDMORE|SS_CANTRCVMORE|SS_ACCEPTCONN)
  
  /*
   * Sockets that can fall back to TPI must ensure that fall back is not
!  * initiated while a thread is using a socket. Otherwise this disables all
!  * future filter attachment.
   */
  #define SO_BLOCK_FALLBACK(so, fn)                               \
          ASSERT(MUTEX_NOT_HELD(&(so)->so_lock));                 \
          rw_enter(&(so)->so_fallback_rwlock, RW_READER);         \
          if ((so)->so_state & (SS_FALLBACK_COMP|SS_FILOP_OK)) {  \
*** 335,344 ****
--- 337,364 ----
                          (so)->so_state &= ~SS_FILOP_OK;         \
                          mutex_exit(&(so)->so_lock);             \
                  }                                               \
          }
  
+ /*
+  * Sockets that can fall back to TPI must ensure that fall back is not
+  * initiated while a thread is using a socket. Otherwise this disables all
+  * future unsafe filter attachment. Safe filters can still attach after
+  * we execute the function in which this macro is used.
+  */
+ #define SO_BLOCK_FALLBACK_SAFE(so, fn)                          \
+         ASSERT(MUTEX_NOT_HELD(&(so)->so_lock));                 \
+         rw_enter(&(so)->so_fallback_rwlock, RW_READER);         \
+         if ((so)->so_state & SS_FALLBACK_COMP) {                \
+                 rw_exit(&(so)->so_fallback_rwlock);             \
+                 return (fn);                                    \
+         } else if (((so)->so_state & SS_FILOP_UNSF) == 0) {     \
+                 mutex_enter(&(so)->so_lock);                    \
+                 (so)->so_state |= SS_FILOP_UNSF;                \
+                 mutex_exit(&(so)->so_lock);                     \
+         }
+ 
  #define SO_UNBLOCK_FALLBACK(so) {                       \
          rw_exit(&(so)->so_fallback_rwlock);             \
  }
  
  #define SO_SND_FLOWCTRLD(so)    \
*** 366,375 ****
--- 386,396 ----
  #define SM_KERNEL               0x200   /* kernel socket */
  
  /* The modes below are only for non-streams sockets */
  #define SM_ACCEPTSUPP           0x400   /* can handle accept() */
  #define SM_SENDFILESUPP         0x800   /* Private: proto supp sendfile  */
+ #define SM_DEFERERR             0x1000  /* Private: defer so_error delivery */
  
  /*
   * Socket versions. Used by the socket library when calling _so_socket().
   */
  #define SOV_STREAM      0       /* Not a socket - just a stream */