+/*
+ * "bootp-response" is the property name which is specified in
+ * the recommended practice doc for obp-tftp. However, pmac
+ * provides a "dhcp-response" property and chrp provides a
+ * "bootpreply-packet" property. The latter appears to begin the
+ * bootp packet at offset 0x2a in the property for some reason.
+ */
+
+struct bootp_property_offset {
+ char *name; /* property name */
+ int offset; /* offset into property where bootp packet occurs */
+};
+static const struct bootp_property_offset bootp_response_properties[] = {
+ { .name = "bootp-response", .offset = 0 },
+ { .name = "dhcp-response", .offset = 0 },
+ { .name = "bootpreply-packet", .offset = 0x2a },
+};
+
+struct bootp_packet {
+ u8 op, htype, hlen, hops;
+ u32 xid;
+ u16 secs, flags;
+ u32 ciaddr, yiaddr, siaddr, giaddr;
+ unsigned char chaddr[16];
+ unsigned char sname[64];
+ unsigned char file[128];
+ /* vendor options go here if we need them */
+};
+
+/*
+ * Search for config file by MAC address, then by IP address.
+ * Basically copying pxelinux's algorithm.
+ * http://syslinux.zytor.com/pxe.php#config
+ */
+static int load_my_config_file(struct boot_fspec_t *orig_fspec)
+{
+ void *bootp_response = NULL;
+ char *propname;
+ struct bootp_packet *packet;
+ int i = 0, size, offset = 0, rc = 0;
+ prom_handle chosen;
+ struct boot_fspec_t fspec = *orig_fspec;
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
+
+ chosen = prom_finddevice("/chosen");
+ if (chosen < 0) {
+ prom_printf("chosen=%d\n", chosen);
+ return 0;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(bootp_response_properties); i++) {
+ propname = bootp_response_properties[i].name;
+ size = prom_getproplen(chosen, propname);
+ if (size <= 0)
+ continue;
+
+ DEBUG_F("using /chosen/%s\n", propname);
+ offset = bootp_response_properties[i].offset;
+ break;
+ }
+
+ if (size <= 0)
+ goto out;
+
+ if (sizeof(*packet) > size - offset) {
+ prom_printf("Malformed %s property?\n", propname);
+ goto out;
+ }
+
+ bootp_response = malloc(size);
+ if (!bootp_response)
+ goto out;
+
+ if (prom_getprop(chosen, propname, bootp_response, size) < 0)
+ goto out;
+
+ packet = bootp_response + offset;
+
+ /*
+ * First, try to match on mac address with the hardware type
+ * prepended.
+ */
+
+ /* 3 chars per byte in chaddr + 2 chars for htype + /etc/ +\0 */
+ fspec.file = malloc(packet->hlen * 3 + 2 + 6);
+ if (!fspec.file)
+ goto out;
+
+ if (_machine == _MACH_chrp)
+ sprintf(fspec.file, "/etc/%02x", packet->htype);
+ else
+ sprintf(fspec.file, "%02x", packet->htype);
+
+ for (i = 0; i < packet->hlen; i++) {
+ char tmp[4];
+ sprintf(tmp, "-%02x", packet->chaddr[i]);
+ strcat(fspec.file, tmp);
+ }
+
+ rc = load_config_file(&fspec);
+ if (rc)
+ goto out;
+
+
+ /*
+ * Now try to match on IP.
+ */
+ free(fspec.file);
+ fspec.file = malloc(9);
+ sprintf(fspec.file, "%08X", packet->yiaddr);
+
+ while (strlen(fspec.file)) {
+ rc = load_config_file(&fspec);
+ if (rc)
+ goto out;
+ /* Chop one digit off the end, try again */
+ fspec.file[strlen(fspec.file) - 1] = '\0';
+ }
+
+ out:
+ if (rc) /* modify original only on success */
+ orig_fspec->file = fspec.file;
+ else
+ free(fspec.file);
+ free(bootp_response);
+ return rc;
+}
+