[PATCH v5 3/5] net/dhcp: Set net_<interface>_client{id, uuid} variables from DHCP options

[Javier Martinez Canillas]

From: Paulo Flabiano Smorigo <address@hidden>

This patch sets a net_<interface>_clientid and net_<interface>_clientuuid
GRUB environment variables, using the DHCP client ID and UUID options if
these are found.

In the same way than net_<interface>_<option> variables are set for other
options such domain name, boot file, next server, etc.

Signed-off-by: Paulo Flabiano Smorigo <address@hidden>
Signed-off-by: Javier Martinez Canillas <address@hidden>
Reviewed-by: Daniel Kiper <address@hidden>

---

Changes in v5:
- Don't mix variable declaration and code.
- Don't initialize variable without need.
- Check for memory allocation failure.
- Add missing grub_free().

Changes in v4: None
Changes in v3:
- Use decimal numbers for the newly added DHCP client ID and UUID options.

Changes in v2:
- Use the existing grub_env_set_net_property() and remove duplicated code.

 grub-core/net/bootp.c | 52 ++++++++++++++++++++++++++++++++++++-------
 include/grub/net.h    |  2 ++
 2 files changed, 46 insertions(+), 8 deletions(-)

diff --git grub-core/net/bootp.c grub-core/net/bootp.c
index 04cfbb04504..351ec2b4565 100644
--- grub-core/net/bootp.c
+++ grub-core/net/bootp.c
@@ -95,6 +95,14 @@ enum
 /* Max timeout when waiting for BOOTP/DHCP reply */
 #define GRUB_DHCP_MAX_PACKET_TIMEOUT 32
 
+static char
+hexdigit (grub_uint8_t val)
+{
+  if (val < 10)
+    return val + '0';
+  return val + 'a' - 10;
+}
+
 static const void *
 find_dhcp_option (const struct grub_net_bootp_packet *bp, grub_size_t size,
                  grub_uint8_t opt_code, grub_uint8_t *opt_len)
@@ -152,6 +160,9 @@ again:
       if (i + taglength >= size)
        return NULL;
 
+      grub_dprintf("net", "DHCP option %u (0x%02x) found with length %u.\n",
+                   tagtype, tagtype, taglength);
+
       /* FIXME RFC 3396 options concatentation */
       if (tagtype == opt_code)
        {
@@ -406,6 +417,39 @@ grub_net_configure_by_dhcp_ack (const char *name,
   if (opt && opt_len)
     grub_env_set_net_property (name, "extensionspath", (const char *) opt, 
opt_len);
   
+  opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_CLIENT_ID, &opt_len);
+  if (opt && opt_len)
+    grub_env_set_net_property (name, "clientid", (const char *) opt, opt_len);
+
+  opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_CLIENT_UUID, &opt_len);
+  if (opt && opt_len == 17)
+    {
+      /* The format is 9cfe245e-d0c8-bd45-a79f-54ea5fbd3d97 */
+      char *val;
+      int i, j = 0;
+
+      opt += 1;
+      opt_len -= 1;
+
+      val = grub_malloc (2 * opt_len + 4 + 1);
+      if (!val)
+          return inter;
+
+      for (i = 0; i < opt_len; i++)
+        {
+          val[2 * i + j] = hexdigit (opt[i] >> 4);
+          val[2 * i + 1 + j] = hexdigit (opt[i] & 0xf);
+
+          if ((i == 3) || (i == 5) || (i == 7) || (i == 9))
+            {
+              j++;
+              val[2 * i + 1+ j] = '-';
+            }
+        }
+      grub_env_set_net_property (name, "clientuuid", (char *) val, 2 * opt_len 
+ 4);
+      grub_free (val);
+    }
+
   inter->dhcp_ack = grub_malloc (size);
   if (inter->dhcp_ack)
     {
@@ -631,14 +675,6 @@ grub_net_process_dhcp (struct grub_net_buff *nb,
     }
 }
 
-static char
-hexdigit (grub_uint8_t val)
-{
-  if (val < 10)
-    return val + '0';
-  return val + 'a' - 10;
-}
-
 static grub_err_t
 grub_cmd_dhcpopt (struct grub_command *cmd __attribute__ ((unused)),
                  int argc, char **args)
diff --git include/grub/net.h include/grub/net.h
index b5fedb28b9c..c00b0ab117c 100644
--- include/grub/net.h
+++ include/grub/net.h
@@ -467,8 +467,10 @@ enum
     GRUB_NET_DHCP_MESSAGE_TYPE = 53,
     GRUB_NET_DHCP_SERVER_IDENTIFIER = 54,
     GRUB_NET_DHCP_PARAMETER_REQUEST_LIST = 55,
+    GRUB_NET_BOOTP_CLIENT_ID = 61,
     GRUB_NET_DHCP_TFTP_SERVER_NAME = 66,
     GRUB_NET_DHCP_BOOTFILE_NAME = 67,
+    GRUB_NET_BOOTP_CLIENT_UUID = 97,
     GRUB_NET_BOOTP_END = 255
   };
 
-- 
2.21.0