slirp: replace qemu_notify_event() with a callback

Introduce a SlirpCb callback to kick the main io-thread.

Add an intermediary sodrop() function that will call SlirpCb.notify
callback when sbdrop() returns true.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

net/slirp.c

@@ -205,6 +205,7 @@ static const SlirpCb slirp_cb = {
     .timer_mod = net_slirp_timer_mod,
     .register_poll_fd = net_slirp_register_poll_fd,
     .unregister_poll_fd = net_slirp_unregister_poll_fd,
+    .notify = qemu_notify_event,
 };
 
 static int net_slirp_init(NetClientState *peer, const char *model,

slirp/libslirp.h

@@ -31,6 +31,8 @@ typedef struct SlirpCb {
     void (*register_poll_fd)(int fd);
     /* Unregister a fd */
     void (*unregister_poll_fd)(int fd);
+    /* Kick the io-thread, to signal that new events may be processed */
+    void (*notify)(void);
 } SlirpCb;
 
 

slirp/sbuf.c

@@ -17,7 +17,7 @@ sbfree(struct sbuf *sb)
 	free(sb->sb_data);
 }
 
-void
+bool
 sbdrop(struct sbuf *sb, int num)
 {
     int limit = sb->sb_datalen / 2;
@@ -34,8 +34,10 @@ sbdrop(struct sbuf *sb, int num)
 		sb->sb_rptr -= sb->sb_datalen;
 
     if (sb->sb_cc < limit && sb->sb_cc + num >= limit) {
-        qemu_notify_event();
+        return true;
     }
+
+    return false;
 }
 
 void

slirp/sbuf.h

@@ -21,7 +21,7 @@ struct sbuf {
 };
 
 void sbfree(struct sbuf *);
-void sbdrop(struct sbuf *, int);
+bool sbdrop(struct sbuf *, int);
 void sbreserve(struct sbuf *, int);
 void sbappend(struct socket *, struct mbuf *);
 void sbcopy(struct sbuf *, int, int, char *);

slirp/socket.c

@@ -928,3 +928,10 @@ void sotranslate_accept(struct socket *so)
         break;
     }
 }
+
+void sodrop(struct socket *s, int num)
+{
+    if (sbdrop(&s->so_snd, num)) {
+        s->slirp->cb->notify();
+    }
+}

slirp/socket.h

@@ -156,6 +156,7 @@ int soreadbuf(struct socket *so, const char *buf, int size);
 void sotranslate_out(struct socket *, struct sockaddr_storage *);
 void sotranslate_in(struct socket *, struct sockaddr_storage *);
 void sotranslate_accept(struct socket *);
+void sodrop(struct socket *, int num);
 
 
 #endif /* SLIRP_SOCKET_H */

slirp/tcp_input.c

@@ -506,7 +506,7 @@ findso:
 				    SEQ_GT(ti->ti_ack, tp->t_rtseq))
 					tcp_xmit_timer(tp, tp->t_rtt);
 				acked = ti->ti_ack - tp->snd_una;
-				sbdrop(&so->so_snd, acked);
+				sodrop(so, acked);
 				tp->snd_una = ti->ti_ack;
 				m_free(m);
 
@@ -1118,10 +1118,10 @@ trimthenstep6:
 		}
 		if (acked > so->so_snd.sb_cc) {
 			tp->snd_wnd -= so->so_snd.sb_cc;
-			sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);
+			sodrop(so, (int)so->so_snd.sb_cc);
 			ourfinisacked = 1;
 		} else {
-			sbdrop(&so->so_snd, acked);
+			sodrop(so, acked);
 			tp->snd_wnd -= acked;
 			ourfinisacked = 0;
 		}