* Re: [Qemu-devel] [PATCH 1/1] Making pxe working in the "NAT" mode
2007-02-14 22:16 [Qemu-devel] [PATCH 1/1] Making pxe working in the "NAT" mode Erwan Velu
@ 2007-02-16 3:49 ` Anthony Liguori
2007-02-16 10:12 ` Erwan Velu
0 siblings, 1 reply; 3+ messages in thread
From: Anthony Liguori @ 2007-02-16 3:49 UTC (permalink / raw)
To: qemu-devel; +Cc: Erwan Velu
[-- Attachment #1: Type: text/plain, Size: 2999 bytes --]
Erwan Velu wrote:
> Hey folks,
> I saw the lastest qemu support pxe so I tried it using the following
> command:
>
> qemu -hda /tmp/a.img -net nic n- user -boot n
>
> Note that now qemu support pxe mode, the mandatory -hda option is no
> more mandatory but this is not directly linked to my patch.
> I saw qemu integrates a dhcp & a tftp server but they don't seems to
> be configured/developped for a pxe boot process.
> Qemu says "no filename" and exits.
Hi Erwan,
I really like the idea of your patch. Of course, the hard coding is not
really reasonable :-) Also, PXE is an x86-ism. What you've really done
is added a mechanism to publish a BOOTP name. We do need to add a new
option too as one may want to use -boot n without publishing a BOOTP
filename.
Using your patch as a basis, I've written three patches. The first one
is the tsize negotiation fix for the TFTP server. The second adds a
-bootp option for specifying the location of the BOOTP image. The third
changes the -tftp option to take root directory. The end result, is
that now you can say:
qemu -hda /tmp/a.img -boot n -tftp ~/tftpboot -bootp /pxelinux.0
And you get the same results without the hard coding. What do you think?
Regards,
Anthony Liguori
> A friend of I asked me "how do you boot using pxe in qemu when you
> don't have a dhcp & a tftp server ?".
> So I started to look how we can do that, I modified bootp to catch the
> field 60 of a dhcp request to find if its a pxe request or not.
> If yes, I set the filename to "/pxelinux.0", currently this is
> harcoded, maybe you can help me to find a better way to specify a
> bootloader.
>
> Then, I've patched the tftp server to change the default rootdir in my
> home dir. "~/tftpboot". This is just for a Proof-of-concept, other
> methods could be fine. We can also imagine searching in a path
> restricted to the admin and then in the user dir. So it can give the
> admin the ability of defining some pxe boot for all the vm of a
> system or in the user dir if the user wants to have a special pxe
> boot scheme.
>
> The last patch I did on the tftp server, is to allow the tsize
> negociation because pxelinux needs it.
>
> This patch apply to 0.9.0, once it is applied and compiled here come
> the test procedure:
>
> create a ~/tftpboot/pxelinux.cfg directory
> copy pxelinux.0 in ~/tfptboot/
> create a pxelinux configuration file called "default" in
> ~/tftpboot/pxelinux.cfg
>
> Et voila ;)
>
> Just call "qemu -hda /tmp/a.img -net nic n- user -boot n", it will
> start pxelinux.
>
> I think this patch is very usefull because it give users & admin the
> ability to use pxe inside the VM without installing the full
> configuration (dhcp,tftp).
> This patch is mainly a proof-of-concept, this patch can be improved,
> comments and feedback are welcome.
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>
[-- Attachment #2: slirp-bootp.diff --]
[-- Type: text/x-patch, Size: 2981 bytes --]
diff -r ea5eb79ade8d slirp/bootp.c
--- a/slirp/bootp.c Thu Feb 15 16:49:28 2007 -0600
+++ b/slirp/bootp.c Thu Feb 15 16:49:30 2007 -0600
@@ -38,6 +38,8 @@ typedef struct {
BOOTPClient bootp_clients[NB_ADDR];
+const char *bootp_filename;
+
static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
#ifdef DEBUG
@@ -168,6 +170,10 @@ static void bootp_reply(struct bootp_t *
goto new_addr;
}
}
+
+ if (bootp_filename)
+ snprintf(rbp->bp_file, sizeof(rbp->bp_file), "%s", bootp_filename);
+
dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr));
saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS);
diff -r ea5eb79ade8d vl.c
--- a/vl.c Thu Feb 15 16:49:28 2007 -0600
+++ b/vl.c Thu Feb 15 16:57:07 2007 -0600
@@ -6488,6 +6488,7 @@ void help(void)
"\n"
#ifdef CONFIG_SLIRP
"-tftp prefix allow tftp access to files starting with prefix [-net user]\n"
+ "-bootp file advertise file in BOOTP replies\n"
#ifndef _WIN32
"-smb dir allow SMB access to files in 'dir' [-net user]\n"
#endif
@@ -6576,6 +6577,7 @@ enum {
QEMU_OPTION_net,
QEMU_OPTION_tftp,
+ QEMU_OPTION_bootp,
QEMU_OPTION_smb,
QEMU_OPTION_redir,
@@ -6652,6 +6654,7 @@ const QEMUOption qemu_options[] = {
{ "net", HAS_ARG, QEMU_OPTION_net},
#ifdef CONFIG_SLIRP
{ "tftp", HAS_ARG, QEMU_OPTION_tftp },
+ { "bootp", HAS_ARG, QEMU_OPTION_bootp },
#ifndef _WIN32
{ "smb", HAS_ARG, QEMU_OPTION_smb },
#endif
@@ -7185,6 +7188,9 @@ int main(int argc, char **argv)
case QEMU_OPTION_tftp:
tftp_prefix = optarg;
break;
+ case QEMU_OPTION_bootp:
+ bootp_filename = optarg;
+ break;
#ifndef _WIN32
case QEMU_OPTION_smb:
net_slirp_smb(optarg);
diff -r ea5eb79ade8d vl.h
--- a/vl.h Thu Feb 15 16:49:28 2007 -0600
+++ b/vl.h Thu Feb 15 16:49:30 2007 -0600
@@ -163,6 +163,7 @@ extern int no_quit;
extern int no_quit;
extern int semihosting_enabled;
extern int autostart;
+extern const char *bootp_filename;
#define MAX_OPTION_ROMS 16
extern const char *option_rom[MAX_OPTION_ROMS];
diff -r ea5eb79ade8d qemu-doc.texi
--- a/qemu-doc.texi Thu Feb 15 16:49:28 2007 -0600
+++ b/qemu-doc.texi Thu Feb 15 16:57:23 2007 -0600
@@ -445,6 +445,16 @@ guest must be configured in binary mode
guest must be configured in binary mode (use the command @code{bin} of
the Unix TFTP client). The host IP address on the guest is as usual
10.0.2.2.
+
+@item -bootp file
+When using the user mode network stack, broadcast @var{file} as the BOOTP
+filename. In conjunction with @option{-tftp}, this can be used to network boot
+a guest from a local directory.
+
+Example (using pxelinux):
+@example
+qemu -hda linux.img -boot n -tftp /path/to/tftp/files -bootp /pxelinux.0
+@end example
@item -smb dir
When using the user mode network stack, activate a built-in SMB
[-- Attachment #3: slirp-tftp-oack.diff --]
[-- Type: text/x-patch, Size: 2781 bytes --]
diff -r 153828edbad3 slirp/tftp.c
--- a/slirp/tftp.c Thu Feb 15 16:37:56 2007 -0600
+++ b/slirp/tftp.c Thu Feb 15 21:37:26 2007 -0600
@@ -120,6 +120,45 @@ static int tftp_read_data(struct tftp_se
return bytes_read;
}
+static int tftp_send_oack(struct tftp_session *spt,
+ const char *key, uint32_t value,
+ struct tftp_t *recv_tp)
+{
+ struct sockaddr_in saddr, daddr;
+ struct mbuf *m;
+ struct tftp_t *tp;
+ int n = 0;
+
+ m = m_get();
+
+ if (!m)
+ return -1;
+
+ memset(m->m_data, 0, m->m_size);
+
+ m->m_data += if_maxlinkhdr;
+ tp = (void *)m->m_data;
+ m->m_data += sizeof(struct udpiphdr);
+
+ tp->tp_op = htons(TFTP_OACK);
+ n += sprintf(tp->x.tp_buf + n, "%s", key) + 1;
+ n += sprintf(tp->x.tp_buf + n, "%u", value) + 1;
+
+ saddr.sin_addr = recv_tp->ip.ip_dst;
+ saddr.sin_port = recv_tp->udp.uh_dport;
+
+ daddr.sin_addr = spt->client_ip;
+ daddr.sin_port = spt->client_port;
+
+ m->m_len = sizeof(struct tftp_t) - 514 + n -
+ sizeof(struct ip) - sizeof(struct udphdr);
+ udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+
+ return 0;
+}
+
+
+
static int tftp_send_error(struct tftp_session *spt,
u_int16_t errorcode, const char *msg,
struct tftp_t *recv_tp)
@@ -273,6 +312,8 @@ static void tftp_handle_rrq(struct tftp_
return;
}
+ k += 6;/* skipping octet*/
+
/* do sanity checks on the filename */
if ((spt->filename[0] != '/')
@@ -297,6 +338,48 @@ static void tftp_handle_rrq(struct tftp_
return;
}
+ if (src[n - 1] != 0) {
+ tftp_send_error(spt, 2, "Access violation", tp);
+ return;
+ }
+
+ while (k < n) {
+ const char *key, *value;
+
+ key = src + k;
+ k += strlen(key) + 1;
+
+ if (k >= n) {
+ tftp_send_error(spt, 2, "Access violation", tp);
+ return;
+ }
+
+ value = src + k;
+ k += strlen(value) + 1;
+
+ if (strcmp(key, "tsize") == 0) {
+ int tsize = atoi(value);
+ struct stat stat_p;
+
+ if (tsize == 0 && tftp_prefix) {
+ char buffer[1024];
+ int len;
+
+ len = snprintf(buffer, sizeof(buffer), "%s/%s",
+ tftp_prefix, spt->filename);
+
+ if (stat(buffer, &stat_p) == 0)
+ tsize = stat_p.st_size;
+ else {
+ tftp_send_error(spt, 1, "File not found", tp);
+ return;
+ }
+ }
+
+ tftp_send_oack(spt, "tsize", tsize, tp);
+ }
+ }
+
tftp_send_data(spt, 1, tp);
}
diff -r 153828edbad3 slirp/tftp.h
--- a/slirp/tftp.h Thu Feb 15 16:37:56 2007 -0600
+++ b/slirp/tftp.h Thu Feb 15 16:37:57 2007 -0600
@@ -9,6 +9,7 @@
#define TFTP_DATA 3
#define TFTP_ACK 4
#define TFTP_ERROR 5
+#define TFTP_OACK 6
#define TFTP_FILENAME_MAX 512
[-- Attachment #4: tftp-root.diff --]
[-- Type: text/x-patch, Size: 2500 bytes --]
diff -r 91f98dfbdc3f qemu-doc.texi
--- a/qemu-doc.texi Thu Feb 15 21:22:02 2007 -0600
+++ b/qemu-doc.texi Thu Feb 15 21:22:03 2007 -0600
@@ -438,13 +438,12 @@ override the default configuration (@opt
override the default configuration (@option{-net nic -net user}) which
is activated if no @option{-net} options are provided.
-@item -tftp prefix
+@item -tftp dir
When using the user mode network stack, activate a built-in TFTP
-server. All filenames beginning with @var{prefix} can be downloaded
-from the host to the guest using a TFTP client. The TFTP client on the
-guest must be configured in binary mode (use the command @code{bin} of
-the Unix TFTP client). The host IP address on the guest is as usual
-10.0.2.2.
+server. The files in @var{dir} will be exposed as the root of a TFTP server.
+The TFTP client on the guest must be configured in binary mode (use the command
+@code{bin} of the Unix TFTP client). The host IP address on the guest is as
+usual 10.0.2.2.
@item -bootp file
When using the user mode network stack, broadcast @var{file} as the BOOTP
diff -r 91f98dfbdc3f slirp/tftp.c
--- a/slirp/tftp.c Thu Feb 15 21:22:02 2007 -0600
+++ b/slirp/tftp.c Thu Feb 15 21:22:03 2007 -0600
@@ -102,8 +102,15 @@ static int tftp_read_data(struct tftp_se
{
int fd;
int bytes_read = 0;
-
- fd = open(spt->filename, O_RDONLY | O_BINARY);
+ char buffer[1024];
+ int n;
+
+ n = snprintf(buffer, sizeof(buffer), "%s/%s",
+ tftp_prefix, spt->filename);
+ if (n >= sizeof(buffer))
+ return -1;
+
+ fd = open(buffer, O_RDONLY | O_BINARY);
if (fd < 0) {
return -1;
@@ -328,8 +335,7 @@ static void tftp_handle_rrq(struct tftp_
/* only allow exported prefixes */
- if (!tftp_prefix
- || (strncmp(spt->filename, tftp_prefix, strlen(tftp_prefix)) != 0)) {
+ if (!tftp_prefix) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
diff -r 91f98dfbdc3f vl.c
--- a/vl.c Thu Feb 15 21:22:02 2007 -0600
+++ b/vl.c Thu Feb 15 21:22:03 2007 -0600
@@ -6487,7 +6487,7 @@ void help(void)
" is provided, the default is '-net nic -net user'\n"
"\n"
#ifdef CONFIG_SLIRP
- "-tftp prefix allow tftp access to files starting with prefix [-net user]\n"
+ "-tftp dir allow tftp access to files in dir [-net user]\n"
"-bootp file advertise file in BOOTP replies\n"
#ifndef _WIN32
"-smb dir allow SMB access to files in 'dir' [-net user]\n"
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