[klibc] PATCH: ipconfig may accept DHCPOFFER as DHCPACK

[Άλκης Γεωργόπουλος]

I'm resending everything, with the signed-off paragraph included.
Thanks, and again, excuse my ignorance.

I found a bug in ipconfig and I'm sending a proposed patch for it.
I've only seen it happen in 2 dhcp-server environments. Scenario:
ipconfig sends a DHCP_DISCOVER,
server A answers with a DHCP_OFFER,
server B answers with a DHCP_OFFER,
ipconfig sends a DHCP_REQUEST for server A,
ipconfig accepts the DHCP_OFFER from server B instead of DHCP_ACK from
server A. <== BUG

The reason for this was that in dhcp_parse(), DHCPOFFER and DHCPACK
returned the same value (=1). So I had to modify the return values,
and I thought it would be better to return the constants DHCPOFFER,
DHCPACK etc instead of 1,2,3... I tried to keep the changes as minimal
as possible.

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified
    it.

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.

Signed-off-by: Άλκης Γεωργόπουλος <alkisg at gmail.com>

diff -ur ../ipconfig.old/dhcp_proto.c ./dhcp_proto.c
--- ../ipconfig.old/dhcp_proto.c	2008-06-14 01:52:11.000000000 +0300
+++ ./dhcp_proto.c	2008-06-14 02:28:32.000000000 +0300
@@ -71,6 +71,11 @@

 /*
  * Parse a DHCP response packet
+ * Returns:
+ * 0 = Not handled
+ * 2 = DHCPOFFER (from dhcp_proto.h)
+ * 5 = DHCPACK
+ * 6 = DHCPNACK
  */
 static int
 dhcp_parse(struct netdev *dev, struct bootp_hdr *hdr, uint8_t * exts,
int extlen)
@@ -101,19 +106,19 @@

 	switch (type) {
 	case DHCPOFFER:
-		ret = bootp_parse(dev, hdr, exts, extlen);
-		if (ret == 1 && serverid != INADDR_NONE)
+		ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPOFFER : 0;
+		if (ret == DHCPOFFER && serverid != INADDR_NONE)
 			dev->serverid = serverid;
 		DEBUG(("\n   dhcp offer\n"));
 		break;

 	case DHCPACK:
-		ret = bootp_parse(dev, hdr, exts, extlen);
+		ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPACK : 0;
 		DEBUG(("\n   dhcp ack\n"));
 		break;

 	case DHCPNAK:
-		ret = 2;
+		ret = DHCPNAK;
 		DEBUG(("\n   dhcp nak\n"));
 		break;
 	}
@@ -122,6 +127,12 @@

 /*
  * Receive and parse a DHCP packet
+ * Returns:
+ *-1 = Error in packet_recv
+ * 0 = Not handled
+ * 2 = DHCPOFFER (from dhcp_proto.h)
+ * 5 = DHCPACK
+ * 6 = DHCPNACK
  */
 static int dhcp_recv(struct netdev *dev)
 {
diff -ur ../ipconfig.old/main.c ./main.c
--- ../ipconfig.old/main.c	2008-06-14 01:52:11.000000000 +0300
+++ ./main.c	2008-06-14 02:30:45.000000000 +0300
@@ -192,7 +192,7 @@
 		case -1:
 			s->state = DEVST_ERROR;
 			break;
-		case 1:	/* Offer received */
+		case DHCPOFFER:	/* Offer received */
 			s->state = DEVST_DHCPREQ;
 			dhcp_send_request(s->dev);
 			break;
@@ -205,10 +205,10 @@
 		case -1:	/* error */
 			s->state = DEVST_ERROR;
 			break;
-		case 1:	/* ACK received */
+		case DHCPACK:	/* ACK received */
 			s->state = DEVST_COMPLETE;
 			break;
-		case 2:	/* NAK received */
+		case DHCPNAK:	/* NAK received */
 			s->state = DEVST_DHCPDISC;
 			break;
 		}