[PATCH v4 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 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 | 48 +++++++++++++++++++++++++++++++++++--------
 include/grub/net.h    |  3 +++
 2 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/grub-core/net/bootp.c b/grub-core/net/bootp.c
index 04cfbb04504..377006da938 100644
--- a/grub-core/net/bootp.c
+++ b/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 +417,35 @@ 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 */
+
+      opt += 1;
+      opt_len -= 1;
+
+      char *val = grub_malloc (2 * opt_len + 4 + 1);
+      int i = 0;
+      int j = 0;
+      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);
+    }
+
   inter->dhcp_ack = grub_malloc (size);
   if (inter->dhcp_ack)
     {
@@ -631,14 +671,6 @@ 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 a/include/grub/net.h b/include/grub/net.h
index b5fedb28b9c..9668808dbca 100644
--- a/include/grub/net.h
+++ b/include/grub/net.h
@@ -454,6 +454,7 @@ struct grub_net_bootp_packet
 
 enum
   {
+
     GRUB_NET_BOOTP_PAD = 0,
     GRUB_NET_BOOTP_NETMASK = 1,
     GRUB_NET_BOOTP_ROUTER = 3,
@@ -467,8 +468,10 @@ 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