Merge tag 'samuel-thibault' of https://people.debian.org/~sthibault/qemu into staging

Add a feature for mapping a host unix socket to a guest tcp socket

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# gpg: Signature made Sun 05 Oct 2025 12:17:24 PM PDT
# gpg:                using RSA key E2F46417B3BC6AC01EAB1D85DCFCAD349BA2D52F
# gpg: Good signature from "Samuel Thibault <samuel.thibault@ens-lyon.org>" [unknown]
# gpg:                 aka "Samuel Thibault <sthibault@debian.org>" [unknown]
# gpg:                 aka "Samuel Thibault <samuel.thibault@gnu.org>" [unknown]
# gpg:                 aka "Samuel Thibault <samuel.thibault@inria.fr>" [unknown]
# gpg:                 aka "Samuel Thibault <samuel.thibault@labri.fr>" [unknown]
# gpg:                 aka "Samuel Thibault <samuel.thibault@aquilenet.fr>" [unknown]
# gpg:                 aka "Samuel Thibault <samuel.thibault@u-bordeaux.fr>" [unknown]
# gpg:                 aka "Samuel Thibault <sthibault@hypra.fr>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 900C B024 B679 31D4 0F82  304B D017 8C76 7D06 9EE6
#      Subkey fingerprint: E2F4 6417 B3BC 6AC0 1EAB  1D85 DCFC AD34 9BA2 D52F

* tag 'samuel-thibault' of https://people.debian.org/~sthibault/qemu:
  Add a feature for mapping a host unix socket to a guest tcp socket

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 87 insertions, 27 deletions

diff --git a/net/slirp.c b/net/slirp.c
index 0a1c2a5eac..c627a9dd24 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -732,6 +732,7 @@ static SlirpState *slirp_lookup(Monitor *mon, const char *id)
 
 void hmp_hostfwd_remove(Monitor *mon, const QDict *qdict)
 {
+    /* TODO: support removing unix fwd */
     struct sockaddr_in host_addr = {
         .sin_family = AF_INET,
         .sin_addr = {
@@ -800,12 +801,13 @@ void hmp_hostfwd_remove(Monitor *mon, const QDict *qdict)
 
 static int slirp_hostfwd(SlirpState *s, const char *redir_str, Error **errp)
 {
-    struct sockaddr_in host_addr = {
-        .sin_family = AF_INET,
-        .sin_addr = {
-            .s_addr = INADDR_ANY,
-        },
-    };
+    union {
+        struct sockaddr_in in;
+#if !defined(WIN32) && SLIRP_CHECK_VERSION(4, 7, 0)
+        struct sockaddr_un un;
+#endif
+    } host_addr = {0};
+
     struct sockaddr_in guest_addr = {
         .sin_family = AF_INET,
         .sin_addr = {
@@ -816,9 +818,13 @@ static int slirp_hostfwd(SlirpState *s, const char *redir_str, Error **errp)
     int host_port, guest_port;
     const char *p;
     char buf[256];
-    int is_udp;
+    int is_udp = 0;
+#if !defined(WIN32) && SLIRP_CHECK_VERSION(4, 7, 0)
+    int is_unix = 0;
+#endif
     const char *end;
     const char *fail_reason = "Unknown reason";
+    socklen_t host_addr_size;
 
     p = redir_str;
     if (!p || get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
@@ -829,30 +835,83 @@ static int slirp_hostfwd(SlirpState *s, const char *redir_str, Error **errp)
         is_udp = 0;
     } else if (!strcmp(buf, "udp")) {
         is_udp = 1;
-    } else {
-        fail_reason = "Bad protocol name";
-        goto fail_syntax;
     }
-
-    if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
-        fail_reason = "Missing : separator";
-        goto fail_syntax;
+#if !defined(WIN32) && SLIRP_CHECK_VERSION(4, 7, 0)
+    else if (!strcmp(buf, "unix")) {
+        is_unix = 1;
     }
-    if (buf[0] != '\0' && !inet_aton(buf, &host_addr.sin_addr)) {
-        fail_reason = "Bad host address";
+#endif
+    else {
+        fail_reason = "Bad protocol name";
         goto fail_syntax;
     }
 
-    if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
-        fail_reason = "Bad host port separator";
-        goto fail_syntax;
-    }
-    err = qemu_strtoi(buf, &end, 0, &host_port);
-    if (err || host_port < 0 || host_port > 65535) {
-        fail_reason = "Bad host port";
-        goto fail_syntax;
+#if !defined(WIN32) && SLIRP_CHECK_VERSION(4, 7, 0)
+    if (is_unix) {
+        if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
+            fail_reason = "Missing - separator";
+            goto fail_syntax;
+        }
+        if (buf[0] == '\0') {
+            fail_reason = "Missing unix socket path";
+            goto fail_syntax;
+        }
+        if (buf[0] != '/') {
+            fail_reason = "unix socket path must be absolute";
+            goto fail_syntax;
+        }
+
+        size_t path_len = strlen(buf);
+        if (path_len > sizeof(host_addr.un.sun_path) - 1) {
+            fail_reason = "Unix socket path is too long";
+            goto fail_syntax;
+        }
+
+        struct stat st;
+        if (stat(buf, &st) == 0) {
+            if (!S_ISSOCK(st.st_mode)) {
+                fail_reason = "file exists and it's not unix socket";
+                goto fail_syntax;
+            }
+
+            if (unlink(buf) < 0) {
+                error_setg_errno(errp, errno, "Failed to unlink '%s'", buf);
+                goto fail_syntax;
+            }
+        }
+        host_addr.un.sun_family = AF_UNIX;
+        memcpy(host_addr.un.sun_path, buf, path_len);
+        host_addr_size = sizeof(host_addr.un);
+    } else
+#endif
+    {
+        host_addr.in.sin_family = AF_INET;
+        host_addr.in.sin_addr.s_addr = INADDR_ANY;
+
+        if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
+            fail_reason = "Missing : separator";
+            goto fail_syntax;
+        }
+
+        if (buf[0] != '\0' && !inet_aton(buf, &host_addr.in.sin_addr)) {
+            fail_reason = "Bad host address";
+            goto fail_syntax;
+        }
+
+        if (get_str_sep(buf, sizeof(buf), &p, '-') < 0) {
+            fail_reason = "Bad host port separator";
+            goto fail_syntax;
+        }
+
+        err = qemu_strtoi(buf, &end, 0, &host_port);
+        if (err || host_port < 0 || host_port > 65535) {
+            fail_reason = "Bad host port";
+            goto fail_syntax;
+        }
+
+        host_addr.in.sin_port = htons(host_port);
+        host_addr_size = sizeof(host_addr.in);
     }
-    host_addr.sin_port = htons(host_port);
 
     if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
         fail_reason = "Missing guest address";
@@ -872,12 +931,13 @@ static int slirp_hostfwd(SlirpState *s, const char *redir_str, Error **errp)
 
 #if SLIRP_CHECK_VERSION(4, 5, 0)
     err = slirp_add_hostxfwd(s->slirp,
-            (struct sockaddr *) &host_addr, sizeof(host_addr),
+            (struct sockaddr *) &host_addr, host_addr_size,
             (struct sockaddr *) &guest_addr, sizeof(guest_addr),
             is_udp ? SLIRP_HOSTFWD_UDP : 0);
 #else
+    (void) host_addr_size;
     err = slirp_add_hostfwd(s->slirp, is_udp,
-            host_addr.sin_addr, host_port,
+            host_addr.in.sin_addr, host_port,
             guest_addr.sin_addr, guest_port);
 #endif