[U-Boot] Subject: [PATCH v2] Support for sending DHCP client options

[Gray Remlin]

If CONFIG_BOOTP_OPTIONS is defined at compile-time, the environment
will be checked for the supported DHCPv4 client options during
construction of a "DHCP Discover" or "DHCP Request" packet.  Any
found (as listed below, prefixed with dhcp_) will have their value
included in the dhcp packet.

dhcp_vendor-class-identifier
dhcp_user-class
dhcp_dhcp-client-identifier

Signed-off-by: Gray Remlin <g_remlin at rocketmail.com>
---
v2:     Remove redundant return value from dhcp_options_prep function
        Change dhcp_options_prep function return type to static void
        Correct grammatical error in README

 README              |    7 +++++++
 common/cmd_nvedit.c |    3 +++
 net/bootp.c         |   51
+++++++++++++++++++++++++++++++++++++++++++++++++++
 tools/env/fw_env.c  |    4 +++-
 4 files changed, 64 insertions(+), 1 deletions(-)

diff --git a/README b/README
index a52f3bf..cd892cc 100644
--- a/README
+++ b/README
@@ -1279,6 +1279,7 @@ The following options need to be configured:
                CONFIG_BOOTP_NTPSERVER
                CONFIG_BOOTP_TIMEOFFSET
                CONFIG_BOOTP_VENDOREX
+               CONFIG_BOOTP_OPTIONS

                CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
                environment variable, not the BOOTP server.
@@ -1299,6 +1300,12 @@ The following options need to be configured:
                of the "hostname" environment variable is passed as
                option 12 to the DHCP server.

+               CONFIG_BOOTP_OPTIONS - The environment is checked for the
+               supported DHCPv4 client options (prefixed with dhcp_), any
+               found are sent during a "DHCP Discover" and "DHCP Request".
+               The DHCP server can use this information to conditionally
+               tailor its response.
+
                CONFIG_BOOTP_DHCP_REQUEST_DELAY

                A 32bit value in microseconds for a delay between
diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
index 3d30c32..2094e8e 100644
--- a/common/cmd_nvedit.c
+++ b/common/cmd_nvedit.c
@@ -224,6 +224,9 @@ int _do_env_set (int flag, int argc, char * const
argv[])
        if (ep) {               /* variable exists */
 #ifndef CONFIG_ENV_OVERWRITE
                if ((strcmp (name, "serial#") == 0) ||
+#if defined(CONFIG_BOOTP_OPTIONS)
+                   (strcmp(name, "dhcp_vendor-class-identifier") == 0) ||
+#endif /* CONFIG_BOOTP_OPTIONS */
                    ((strcmp (name, "ethaddr") == 0)
 #if defined(CONFIG_OVERWRITE_ETHADDR_ONCE) && defined(CONFIG_ETHADDR)
                     && (strcmp (ep->data,MK_STR(CONFIG_ETHADDR)) != 0)
diff --git a/net/bootp.c b/net/bootp.c
index 1289e3b..61ecede 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -68,6 +68,53 @@ extern u8 *dhcp_vendorex_prep (u8 *e); /*rtn new e
after add own opts. */
 extern u8 *dhcp_vendorex_proc (u8 *e); /*rtn next e if mine,else NULL  */
 #endif

+#if defined(CONFIG_BOOTP_OPTIONS) /* check environment for dhcp client
options */
+
+/*
+ *     The vendor-specifiable options should not be changeable
+ *     unless CONFIG_ENV_OVERWRITE has been defined, however
+ *     user-specifiable options should be changeable regardless
+ */
+static void dhcp_options_prep(u8 **ep)
+{
+       u8 *e = *ep;
+       char *ptr;
+
+       debug("DHCP Client options start\n");
+
+       /* vendor-specifiable identification string */
+       if ((ptr = getenv("dhcp_vendor-class-identifier"))) {
+               debug("dhcp_vendor-class-identifier=%s\n",ptr);
+               *e++ = 60;
+               *e++ = strlen(ptr);
+               while (*ptr)
+                       *e++ = *ptr++;
+       }
+
+       /* user-specifiable identification string */
+       if ((ptr = getenv("dhcp_dhcp-client-identifier"))) {
+               debug("dhcp_dhcp-client-identifier=%s\n",ptr);
+               *e++ = 61;
+               *e++ = strlen(ptr);
+               while (*ptr)
+                       *e++ = *ptr++;
+       }
+
+       /* user-specifiable identification string */
+       if ((ptr = getenv("dhcp_user-class"))) {
+               debug("dhcp_user-class=%s\n",ptr);
+               *e++ = 77;
+               *e++ = strlen(ptr);
+               while (*ptr)
+                       *e++ = *ptr++;
+       }
+
+       *ep = e;
+       debug("DHCP Client options end\n");
+}
+
+#endif /* CONFIG_BOOTP_OPTIONS */
+
 #endif

 static int BootpCheckPkt(uchar *pkt, unsigned dest, unsigned src,
unsigned len)
@@ -412,6 +459,10 @@ static int DhcpExtended (u8 * e, int message_type,
IPaddr_t ServerID, IPaddr_t R
        }
 #endif

+#if defined(CONFIG_BOOTP_OPTIONS)
+       dhcp_options_prep (&e);
+#endif
+
 #if defined(CONFIG_BOOTP_VENDOREX)
        if ((x = dhcp_vendorex_prep (e)))
                return x - start;
diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 8ff7052..ae37d15 100644
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -391,9 +391,11 @@ int fw_env_write(char *name, char *value)
         */
        if (oldval) {
                /*
-                * Ethernet Address and serial# can be set only once
+                * Ethernet Address, vendor DHCP options,
+                * and serial# can be set only once
                 */
                if ((strcmp (name, "ethaddr") == 0) ||
+                       (strcmp(name, "dhcp_vendor-class-identifier") ==
0) ||
                        (strcmp (name, "serial#") == 0)) {
                        fprintf (stderr, "Can't overwrite \"%s\"\n", name);
                        errno = EROFS;
--