udhcpc: support option 0x79 (static routes) (part of bug 341)

function                                             old     new   delta
xmalloc_optname_optval                                 -     583    +583
dhcp_option_strings                                  258     266      +8
dhcp_options                                          70      72      +2
len_of_option_as_string                               11      12      +1
dhcp_option_lengths                                   11      12      +1
udhcp_run_script                                    1187     669    -518
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/1 up/down: 595/-518)           Total: 77 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 52 insertions, 1 deletions

diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index 76d6e3737..ddb894432 100644
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -48,6 +48,7 @@ const struct dhcp_option dhcp_options[] = {
 #if ENABLE_FEATURE_UDHCP_RFC3397
         { OPTION_STR1035 | OPTION_LIST            , 0x77 }, /* search             */
 #endif
+        { OPTION_STATIC_ROUTES                    , 0x79 }, /* DHCP_STATIC_ROUTES */
         /* MSIE's "Web Proxy Autodiscovery Protocol" support */
         { OPTION_STRING                           , 0xfc }, /* wpad               */
 
@@ -97,6 +98,7 @@ const char dhcp_option_strings[] ALIGN1 =
 #if ENABLE_FEATURE_UDHCP_RFC3397
         "search" "\0"
 #endif
+        "staticroutes" "\0" /* DHCP_STATIC_ROUTES  */
         /* MSIE's "Web Proxy Autodiscovery Protocol" support */
         "wpad" "\0"
         ;
@@ -116,6 +118,8 @@ const uint8_t dhcp_option_lengths[] ALIGN1 = {
         [OPTION_S16] =     2,
         [OPTION_U32] =     4,
         [OPTION_S32] =     4,
+        /* Just like OPTION_STRING, we use minimum length here */
+        [OPTION_STATIC_ROUTES] = 5,
 };
 
 
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 9e624318f..aeed36907 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -20,6 +20,7 @@ enum {
         OPTION_S16,
         OPTION_U32,
         OPTION_S32,
+        OPTION_STATIC_ROUTES,
 };
 
 /* Client requests this option by default */
@@ -68,6 +69,7 @@ enum {
 #define DHCP_VENDOR             0x3c
 #define DHCP_CLIENT_ID          0x3d
 #define DHCP_FQDN               0x51
+#define DHCP_STATIC_ROUTES      0x79
 #define DHCP_END                0xFF
 /* Offsets in option byte sequence */
 #define OPT_CODE                0
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index 94dabf4d1..f315008a3 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -17,6 +17,7 @@
 static const uint8_t len_of_option_as_string[] = {
         [OPTION_IP] =           sizeof("255.255.255.255 "),
         [OPTION_IP_PAIR] =      sizeof("255.255.255.255 ") * 2,
+        [OPTION_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
         [OPTION_STRING] =       1,
 #if ENABLE_FEATURE_UDHCP_RFC3397
         [OPTION_STR1035] =      1,
@@ -51,7 +52,7 @@ static int mton(uint32_t mask)
 
 
 /* Create "opt_name=opt_value" string */
-static char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
+static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
 {
         unsigned upper_length;
         int len, type, optlen;
@@ -106,6 +107,50 @@ static char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *t
                         memcpy(dest, option, len);
                         dest[len] = '\0';
                         return ret;      /* Short circuit this case */
+                case OPTION_STATIC_ROUTES: {
+                        /* Option binary format:
+                         * mask [one byte, 0..32]
+                         * ip [big endian, 0..4 bytes depending on mask]
+                         * router [big endian, 4 bytes]
+                         * may be repeated
+                         *
+                         * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
+                         */
+                        const char *pfx = "";
+
+                        while (len >= 1 + 4) { /* mask + 0-byte ip + router */
+                                uint32_t nip;
+                                uint8_t *p;
+                                unsigned mask;
+                                int bytes;
+
+                                mask = *option++;
+                                if (mask > 32)
+                                        break;
+                                len--;
+
+                                nip = 0;
+                                p = (void*) &nip;
+                                bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
+                                while (--bytes >= 0) {
+                                        *p++ = *option++;
+                                        len--;
+                                }
+                                if (len < 4)
+                                        break;
+
+                                /* print ip/mask */
+                                dest += sprint_nip(dest, pfx, (void*) &nip);
+                                pfx = " ";
+                                dest += sprintf(dest, "/%u ", mask);
+                                /* print router */
+                                dest += sprint_nip(dest, "", option);
+                                option += 4;
+                                len -= 4;
+                        }
+
+                        return ret;
+                }
 #if ENABLE_FEATURE_UDHCP_RFC3397
                 case OPTION_STR1035:
                         /* unpack option into dest; use ret for prefix (i.e., "optname=") */