slirp: invoke client callback before creating timers

The introduction of .timer_new_opaque adds an interesting conundrum.
The Slirp* needs to be stored in .timer_new_opaque so that it can be
passed back to slirp_handle_timer, but it is not returned by slirp_new
and slirp_init until after the first call to .timer_new_opaque (which
is in ip6_init).  This is a problem for programs that, like QEMU, use
more than one Slirp*.

Fix them by passing the Slirp* to a callback before slirp_new returns,
and initializing the timer afterwards.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

6 files changed, 12 insertions, 6 deletions

diff --git a/src/ip6_icmp.c b/src/ip6_icmp.c
index 181989c..0d7ee69 100644
--- a/src/ip6_icmp.c
+++ b/src/ip6_icmp.c
@@ -10,7 +10,7 @@
 #define NDP_Interval \
     g_rand_int_range(slirp->grand, NDP_MinRtrAdvInterval, NDP_MaxRtrAdvInterval)
 
-void icmp6_init(Slirp *slirp)
+void icmp6_post_init(Slirp *slirp)
 {
     if (!slirp->in6_enabled) {
         return;
diff --git a/src/ip6_icmp.h b/src/ip6_icmp.h
index 4420841..9f378f1 100644
--- a/src/ip6_icmp.h
+++ b/src/ip6_icmp.h
@@ -209,7 +209,7 @@ struct ndpopt {
 #define NDP_AdvPrefLifetime 14400
 #define NDP_AdvAutonomousFlag 1
 
-void icmp6_init(Slirp *slirp);
+void icmp6_post_init(Slirp *slirp);
 void icmp6_cleanup(Slirp *slirp);
 void icmp6_input(struct mbuf *);
 void icmp6_forward_error(struct mbuf *m, uint8_t type, uint8_t code, struct in6_addr *src);
diff --git a/src/ip6_input.c b/src/ip6_input.c
index b3d9865..4aca082 100644
--- a/src/ip6_input.c
+++ b/src/ip6_input.c
@@ -11,9 +11,9 @@
  * IP initialization: fill in IP protocol switch table.
  * All protocols not implemented in kernel go to raw IP protocol handler.
  */
-void ip6_init(Slirp *slirp)
+void ip6_post_init(Slirp *slirp)
 {
-    icmp6_init(slirp);
+    icmp6_post_init(slirp);
 }
 
 void ip6_cleanup(Slirp *slirp)
diff --git a/src/libslirp.h b/src/libslirp.h
index 8eb47a0..77396f0 100644
--- a/src/libslirp.h
+++ b/src/libslirp.h
@@ -82,6 +82,8 @@ typedef struct SlirpCb {
      * Fields introduced in SlirpConfig version 4 begin
      */
 
+    /* Initialization has completed and a Slirp* has been created.  */
+    void (*init_completed)(Slirp *slirp, void *opaque);
     /* Create a new timer.  When the timer fires, the application passes
      * the SlirpTimerId and cb_opaque to slirp_handle_timer.  */
     void *(*timer_new_opaque)(SlirpTimerId id, void *cb_opaque, void *opaque);
diff --git a/src/slirp.c b/src/slirp.c
index c92a9a9..1423b01 100644
--- a/src/slirp.c
+++ b/src/slirp.c
@@ -595,7 +595,6 @@ Slirp *slirp_new(const SlirpConfig *cfg, const SlirpCb *callbacks, void *opaque)
 
     if_init(slirp);
     ip_init(slirp);
-    ip6_init(slirp);
 
     m_init(slirp);
 
@@ -645,6 +644,11 @@ Slirp *slirp_new(const SlirpConfig *cfg, const SlirpCb *callbacks, void *opaque)
         slirp->disable_dhcp = false;
     }
 
+    if (slirp->cfg_version >= 4 && slirp->cb->init_completed) {
+        slirp->cb->init_completed(slirp, slirp->opaque);
+    }
+
+    ip6_post_init(slirp);
     return slirp;
 }
 
diff --git a/src/slirp.h b/src/slirp.h
index 50e33a5..35c2be3 100644
--- a/src/slirp.h
+++ b/src/slirp.h
@@ -246,7 +246,7 @@ void ip_stripoptions(register struct mbuf *, struct mbuf *);
 int ip_output(struct socket *, struct mbuf *);
 
 /* ip6_input.c */
-void ip6_init(Slirp *);
+void ip6_post_init(Slirp *);
 void ip6_cleanup(Slirp *);
 void ip6_input(struct mbuf *);