[Qemu-devel] [PATCH] Set hostname in DHCP response

["Ed Swierk" <eswierk@gmail.com>]

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Here is a patch that sets the hostname in the DHCP response generated
by qemu's user-net DHCP server, and adds a new -hostname command line
option to specify the value.

If the guest OS is configured properly, the value received in the DHCP
response is automatically used to set the machine's hostname. (In Red
Hat/Fedora Linuxes, this happens if HOSTNAME is not hardcoded in
/etc/sysconfig/network.)

Feedback welcome.

--Ed

[-- Attachment #2: qemu-hostname.patch --]
[-- Type: text/x-patch, Size: 2889 bytes --]

diff -BurN qemu-snapshot-2006-03-06_23.orig/slirp/bootp.c qemu-snapshot-2006-03-06_23/slirp/bootp.c
--- qemu-snapshot-2006-03-06_23.orig/slirp/bootp.c	2005-06-05 17:11:42.000000000 +0000
+++ qemu-snapshot-2006-03-06_23/slirp/bootp.c	2006-03-10 07:11:19.000000000 +0000
@@ -228,6 +228,16 @@
         val = htonl(LEASE_TIME);
         memcpy(q, &val, 4);
         q += 4;
+
+        if (slirp_hostname && *slirp_hostname) {
+            val = strlen(slirp_hostname);
+            if (val > 32)
+                val = 32;
+            *q++ = RFC1533_HOSTNAME;
+            *q++ = val;
+            memcpy(q, slirp_hostname, val);
+            q += val;
+        }
     }
     *q++ = RFC1533_END;
     
diff -BurN qemu-snapshot-2006-03-06_23.orig/slirp/libslirp.h qemu-snapshot-2006-03-06_23/slirp/libslirp.h
--- qemu-snapshot-2006-03-06_23.orig/slirp/libslirp.h	2005-06-05 17:11:42.000000000 +0000
+++ qemu-snapshot-2006-03-06_23/slirp/libslirp.h	2006-03-10 06:47:32.000000000 +0000
@@ -32,6 +32,7 @@
                    int guest_port);
 
 extern const char *tftp_prefix;
+extern const char *slirp_hostname;
 
 #ifdef __cplusplus
 }
diff -BurN qemu-snapshot-2006-03-06_23.orig/slirp/slirp.c qemu-snapshot-2006-03-06_23/slirp/slirp.c
--- qemu-snapshot-2006-03-06_23.orig/slirp/slirp.c	2005-09-03 10:45:09.000000000 +0000
+++ qemu-snapshot-2006-03-06_23/slirp/slirp.c	2006-03-10 06:46:28.000000000 +0000
@@ -25,6 +25,8 @@
 /* XXX: suppress those select globals */
 fd_set *global_readfds, *global_writefds, *global_xfds;
 
+const char *slirp_hostname = NULL;
+
 #ifdef _WIN32
 
 static int get_dns_addr(struct in_addr *pdns_addr)
diff -BurN qemu-snapshot-2006-03-06_23.orig/vl.c qemu-snapshot-2006-03-06_23/vl.c
--- qemu-snapshot-2006-03-06_23.orig/vl.c	2006-02-20 00:33:36.000000000 +0000
+++ qemu-snapshot-2006-03-06_23/vl.c	2006-03-10 06:45:32.000000000 +0000
@@ -4183,6 +4183,7 @@
 #endif
            "-redir [tcp|udp]:host-port:[guest-host]:guest-port\n"
            "                redirect TCP or UDP connections from host to guest [-net user]\n"
+           "-hostname name  set hostname in DHCP responses\n"
 #endif
            "\n"
            "Linux boot specific:\n"
@@ -4267,6 +4268,7 @@
     QEMU_OPTION_tftp,
     QEMU_OPTION_smb,
     QEMU_OPTION_redir,
+    QEMU_OPTION_hostname,
 
     QEMU_OPTION_kernel,
     QEMU_OPTION_append,
@@ -4332,6 +4334,7 @@
     { "smb", HAS_ARG, QEMU_OPTION_smb },
 #endif
     { "redir", HAS_ARG, QEMU_OPTION_redir },
+    { "hostname", HAS_ARG, QEMU_OPTION_hostname },
 #endif
 
     { "kernel", HAS_ARG, QEMU_OPTION_kernel },
@@ -4785,6 +4788,9 @@
             case QEMU_OPTION_redir:
                 net_slirp_redir(optarg);                
                 break;
+            case QEMU_OPTION_hostname:
+                slirp_hostname = optarg;
+                break;
 #endif
 #ifdef HAS_AUDIO
             case QEMU_OPTION_audio_help: