From: Stefan Reinauer <stefan.reinauer@coreboot.org>
Date: Wed, 27 May 2026 16:06:10 +0000 (-0700)
Subject: slirp: harden backend reinitialization
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=400b40c853f0151f87257f98a3f58c57b0bbec86;p=francis%2Fwinuae.git

slirp: harden backend reinitialization

Ariadne can close and reopen the selected Ethernet backend while
guest software probes or retries card configuration. The SLIRP
backend destroyed callback state before the receive thread was known
to be stopped, and ignored initialization or thread start failures.

Join the receive thread before teardown, keep callback state alive
until shutdown completes, report SLIRP startup failures, and reset or
reuse BOOTP leases across backend restarts.
---

diff --git a/ethernet.cpp b/ethernet.cpp
index 83ceda33..6231e6a9 100644
--- a/ethernet.cpp
+++ b/ethernet.cpp
@@ -122,7 +122,12 @@ int ethernet_open (struct netdriverdata *ndd, void *vsd, void *user, ethernet_go
 			slirp_data = ed;
 			uae_sem_init (&slirp_sem1, 0, 1);
 			uae_sem_init (&slirp_sem2, 0, 1);
-			uae_slirp_init();
+			if (uae_slirp_init() < 0) {
+				slirp_data = NULL;
+				uae_sem_destroy (&slirp_sem1);
+				uae_sem_destroy (&slirp_sem2);
+				return 0;
+			}
 			for (int i = 0; i < MAX_SLIRP_REDIRS; i++) {
 				struct slirp_redir *sr = &currprefs.slirp_redirs[i];
 				if (sr->proto) {
@@ -156,7 +161,13 @@ int ethernet_open (struct netdriverdata *ndd, void *vsd, void *user, ethernet_go
 				}
 			}
 			netmode = ndd->type;
-			uae_slirp_start ();
+			if (!uae_slirp_start ()) {
+				uae_slirp_cleanup ();
+				slirp_data = NULL;
+				uae_sem_destroy (&slirp_sem1);
+				uae_sem_destroy (&slirp_sem2);
+				return 0;
+			}
 		}
 		return 1;
 #endif
@@ -184,9 +195,9 @@ void ethernet_close (struct netdriverdata *ndd, void *vsd)
 		case UAENET_SLIRP:
 		case UAENET_SLIRP_INBOUND:
 		if (slirp_data) {
-			slirp_data = NULL;
 			uae_slirp_end ();
 			uae_slirp_cleanup ();
+			slirp_data = NULL;
 			uae_sem_destroy (&slirp_sem1);
 			uae_sem_destroy (&slirp_sem2);
 		}
diff --git a/slirp/bootp.cpp b/slirp/bootp.cpp
index 0bcd6a7c..31cc48b8 100644
--- a/slirp/bootp.cpp
+++ b/slirp/bootp.cpp
@@ -40,6 +40,11 @@ BOOTPClient bootp_clients[NB_ADDR];
 
 static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
 
+void bootp_reset(void)
+{
+    memset(bootp_clients, 0, sizeof bootp_clients);
+}
+
 static BOOTPClient *get_new_addr(struct in_addr *paddr)
 {
     BOOTPClient *bc;
@@ -144,10 +149,15 @@ static void bootp_reply(struct bootp_t *bp)
     memset(rbp, 0, sizeof(struct bootp_t));
 
     if (dhcp_msg_type == DHCPDISCOVER) {
+        bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr);
+        if (bc)
+            goto have_addr;
     new_addr:
         bc = get_new_addr(&daddr.sin_addr);
-        if (!bc)
+        if (!bc) {
+            m_free(m);
             return;
+        }
         memcpy(bc->macaddr, client_ethaddr, 6);
     } else {
         bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr);
@@ -157,6 +167,7 @@ static void bootp_reply(struct bootp_t *bp)
             goto new_addr;
         }
     }
+have_addr:
 
     saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS);
     saddr.sin_port = htons(BOOTP_SERVER);
diff --git a/slirp/bootp.h b/slirp/bootp.h
index 86762d0a..c3b4df77 100644
--- a/slirp/bootp.h
+++ b/slirp/bootp.h
@@ -113,3 +113,4 @@ struct bootp_t {
 #include "unpacked.h"
 
 void bootp_input(struct mbuf *m);
+void bootp_reset(void);
diff --git a/slirp/slirp.cpp b/slirp/slirp.cpp
index 0df263cd..67610b00 100644
--- a/slirp/slirp.cpp
+++ b/slirp/slirp.cpp
@@ -137,6 +137,7 @@ int slirp_init(void)
 
     link_up = 1;
 
+    bootp_reset();
     if_init();
     ip_init();
 
@@ -159,6 +160,7 @@ void slirp_cleanup(void)
 {
     ip_cleanup();
     m_cleanup();
+	bootp_reset();
 	link_up = 0;
 }
 
diff --git a/slirp_uae.cpp b/slirp_uae.cpp
index 8758532e..c1c4eab3 100644
--- a/slirp_uae.cpp
+++ b/slirp_uae.cpp
@@ -61,7 +61,7 @@ int uae_slirp_init(void)
 
 #ifdef WITH_QEMU_SLIRP
 	if (impl == QEMU_IMPLEMENTATION) {
-		return uae_qemu_uae_init() == NULL;
+		return uae_qemu_uae_init() ? 0 : -1;
 	}
 #endif
 #ifdef WITH_BUILTIN_SLIRP
@@ -140,7 +140,6 @@ extern uae_sem_t slirp_sem2;
 
 static void slirp_receive_func(void *arg)
 {
-	slirp_thread_active = 1;
 	while (slirp_thread_active == 1) {
 		fd_set rfds, wfds, xfds;
 		INT_PTR nfds;