This is the mail archive of the
ecos-discuss@sources.redhat.com
mailing list for the eCos project.
Re: DHCP w/ Win2K server?
Hugo Tyson <hmt@redhat.com> writes:
> "Dan Conti" <danc@iobjects.com> writes:
> > Unfortunately my eCos version is a bit outdated at this point, so if i
> > gave you a patch it almost certainly wouldn't apply properly.
>
> OK, I'll get something together for the trunk.
>
> I believe it will be good to add that tag to all *FOUR* places DHCP sends a
> packet, DHCPSTATE_REQUESTING, RENEWING, REBINDING and the initial broadcast
> one in INIT. 'Course I'll test it, but only with LINUX dhcpd. Comments?
>
> I'll place a patch which should be good for anoncvs here.
And here it is; rather more than the four-times-one-liner we expected...
Please followup here if anyone sees any problems with this tag set, and
requests to add or elide specifics, or if you need real configury of this.
- Huge
Index: net/tcpip/current/ChangeLog
===================================================================
RCS file: /home/cvs/ecc/ecc/net/tcpip/current/ChangeLog,v
retrieving revision 1.147
diff -u -5 -p -r1.147 ChangeLog
--- net/tcpip/current/ChangeLog 2001/11/29 19:10:37 1.147
+++ net/tcpip/current/ChangeLog 2001/11/30 14:16:25
@@ -1,5 +1,21 @@
+2001-11-30 Hugo Tyson <hmt@redhat.com>
+
+ * src/lib/dhcp_prot.c (set_default_dhcp_tags): New routine to
+ insert all the extra woffle we need neatly each time, keeping the
+ state machine's case arms to the real work. The new thing this
+ sets is TAG_DHCP_PARM_REQ_LIST, with a list that matches the
+ default set we get from a LINUX dhcpd. This is because M$ servers
+ need explicit requests for eg. TAG_GATEWAY. Note that I have
+ included configuration to override the set of tags requested here
+ in the source, but not yet backed up by CDL - we'll see whether
+ anyone needs this.
+ (set_variable_tag): New routine to insert a variable pointed-to
+ data item rather than an int of 1,2 or 4 bytes.
+ (do_dhcp): Call set_default_dhcp_tags() every time we send a
+ packet, rather than ad hoc additions in each state.
+
2001-11-29 Jonathan Larmour <jlarmour@redhat.com>
* include/machine/ansi.h: No longer require BSD string function
compatibility macros (in fact they confuse things).
Index: net/tcpip/current/src/lib/dhcp_prot.c
===================================================================
RCS file: /home/cvs/ecc/ecc/net/tcpip/current/src/lib/dhcp_prot.c,v
retrieving revision 1.10
diff -u -5 -p -r1.10 dhcp_prot.c
--- net/tcpip/current/src/lib/dhcp_prot.c 2001/11/19 18:37:51 1.10
+++ net/tcpip/current/src/lib/dhcp_prot.c 2001/11/30 14:16:25
@@ -167,10 +167,54 @@ set_fixed_tag( struct bootp *ppkt,
value >>= 8;
}
return true;
}
+// Note that this does not permit changing the size of an extant tag.
+static int
+set_variable_tag( struct bootp *ppkt,
+ unsigned char tag,
+ cyg_uint8 *pvalue,
+ int len)
+{
+ unsigned char *op;
+
+ // Initially this will only scan the options field.
+ op = &ppkt->bp_vend[4];
+ while (*op != TAG_END) {
+ if ( op > &ppkt->bp_vend[BP_VEND_LEN-1] ) {
+ CYG_FAIL( "Oversize DHCP packet in set_variable_tag" );
+ return false;
+ }
+ if (*op == tag) // Found it...
+ break;
+ op += *(op+1)+2;
+ }
+
+ if (*op == tag) { // Found it...
+ if ( *(op+1) != len ) {
+ CYG_FAIL( "Wrong size in set_variable_tag" );
+ return false; // wrong size
+ }
+ }
+ else { // overwrite the end tag and install a new one
+ if ( op + len + 2 > &ppkt->bp_vend[BP_VEND_LEN-1] ) {
+ CYG_FAIL( "Oversize DHCP packet in set_variable_tag append" );
+ return false;
+ }
+ *op = tag;
+ *(op+1) = len;
+ *(op + len + 2) = TAG_END;
+ }
+ // and insert the value. No order is implied.
+ op += 2; // point to start of value
+ while ( len-- > 0 ) {
+ *op++ = *pvalue++;
+ }
+ return true;
+}
+
// ------------------------------------------------------------------------
// Bring up an interface enough to broadcast, before we know who we are
static int
bring_half_up(const char *intf, struct ifreq *ifrp )
@@ -404,10 +448,49 @@ static inline void new_lease( struct boo
cyg_alarm_initialize( lease->alarm, lease->t1, 0 );
cyg_alarm_enable( lease->alarm );
}
+// ------------------------------------------------------------------------
+// Set all the tags we want to use when sending a packet.
+// This has expanded to a large, explicit set to interwork better
+// with a variety of DHCP servers.
+
+static void set_default_dhcp_tags( struct bootp *xmit )
+{
+ // Explicitly request full set of params that are default for LINUX
+ // dhcp servers, but not default for others. This is rather arbitrary,
+ // but it preserves behaviour for people using those servers.
+ // Perhaps configury of this set will be needed in future?
+ //
+ // Here's the set:
+ static cyg_uint8 req_list[] = {
+#ifdef CYGOPT_NET_DHCP_PARM_REQ_LIST_REPLACE
+ CYGOPT_NET_DHCP_PARM_REQ_LIST_REPLACE ,
+#else
+ TAG_DHCP_SERVER_ID , // DHCP server id: 10.16.19.66
+ TAG_DHCP_LEASE_TIME , // DHCP time 51: 60
+ TAG_DHCP_RENEWAL_TIME , // DHCP time 58: 30
+ TAG_DHCP_REBIND_TIME , // DHCP time 59: 52
+ TAG_SUBNET_MASK , // subnet mask: 255.255.255.0
+ TAG_GATEWAY , // gateway: 10.16.19.66
+ TAG_DOMAIN_SERVER , // domain server: 10.16.19.66
+ TAG_DOMAIN_NAME , // domain name: hmt10.cambridge.redhat.com
+ TAG_IP_BROADCAST , // IP broadcast: 10.16.19.255
+#endif
+#ifdef CYGOPT_NET_DHCP_PARM_REQ_LIST_ADDITIONAL
+ CYGOPT_NET_DHCP_PARM_REQ_LIST_ADDITIONAL ,
+#endif
+ };
+
+ if ( req_list[0] ) // So that one may easily turn it all off by configury
+ set_variable_tag( xmit, TAG_DHCP_PARM_REQ_LIST,
+ &req_list[0], sizeof( req_list ) );
+
+ // Explicitly specify our max message size.
+ set_fixed_tag( xmit, TAG_DHCP_MAX_MSGSZ, BP_MINPKTSZ, 2 );
+}
// ------------------------------------------------------------------------
// the DHCP state machine - this does all the work
int
@@ -557,12 +640,12 @@ do_dhcp(const char *intf, struct bootp *
bcopy(ifr.ifr_hwaddr.sa_data, &xmit->bp_chaddr, xmit->bp_hlen);
bcopy(mincookie, xmit->bp_vend, sizeof(mincookie));
// remove the next line to test ability to handle bootp packets.
set_fixed_tag( xmit, TAG_DHCP_MESS_TYPE, DHCPDISCOVER, 1 );
-
- set_fixed_tag( xmit, TAG_DHCP_MAX_MSGSZ, BP_MINPKTSZ, 2 );
+ // Set all the tags we want to use when sending a packet
+ set_default_dhcp_tags( xmit );
#ifdef CYGDBG_NET_DHCP_CHATTER
diag_printf( "---------DHCPSTATE_INIT sending:\n" );
show_bootp( intf, xmit );
#endif
@@ -648,12 +731,12 @@ do_dhcp(const char *intf, struct bootp *
// Fill in the BOOTP request - DHCPREQUEST packet
xmit->bp_op = BOOTREQUEST;
xmit->bp_flags = htons(0x8000); // BROADCAST FLAG
set_fixed_tag( xmit, TAG_DHCP_MESS_TYPE, DHCPREQUEST, 1 );
- set_fixed_tag( xmit, TAG_DHCP_MAX_MSGSZ, BP_MINPKTSZ, 2 );
-
+ // Set all the tags we want to use when sending a packet
+ set_default_dhcp_tags( xmit );
// And this will be a new one:
set_fixed_tag( xmit, TAG_DHCP_REQ_IP, ntohl(xmit->bp_yiaddr.s_addr), 4 );
#ifdef CYGDBG_NET_DHCP_CHATTER
diag_printf( "---------DHCPSTATE_REQUESTING sending:\n" );
@@ -765,12 +848,12 @@ do_dhcp(const char *intf, struct bootp *
xmit->bp_flags = htons(0); // No BROADCAST FLAG
// Use the *client* address here:
xmit->bp_ciaddr.s_addr = xmit->bp_yiaddr.s_addr;
set_fixed_tag( xmit, TAG_DHCP_MESS_TYPE, DHCPREQUEST, 1 );
- set_fixed_tag( xmit, TAG_DHCP_MAX_MSGSZ, BP_MINPKTSZ, 2 );
-
+ // Set all the tags we want to use when sending a packet
+ set_default_dhcp_tags( xmit );
// And this will be a new one:
set_fixed_tag( xmit, TAG_DHCP_REQ_IP, ntohl(xmit->bp_yiaddr.s_addr), 4 );
// Set unicast address to *server*
server_addr.sin_addr.s_addr = res->bp_siaddr.s_addr;
@@ -864,12 +947,12 @@ do_dhcp(const char *intf, struct bootp *
xmit->bp_flags = htons(0); // no BROADCAST FLAG
// Use the *client* address here:
xmit->bp_ciaddr.s_addr = xmit->bp_yiaddr.s_addr;
set_fixed_tag( xmit, TAG_DHCP_MESS_TYPE, DHCPREQUEST, 1 );
- set_fixed_tag( xmit, TAG_DHCP_MAX_MSGSZ, BP_MINPKTSZ, 2 );
-
+ // Set all the tags we want to use when sending a packet
+ set_default_dhcp_tags( xmit );
// And this will be a new one:
set_fixed_tag( xmit, TAG_DHCP_REQ_IP, ntohl(xmit->bp_yiaddr.s_addr), 4 );
#ifdef CYGDBG_NET_DHCP_CHATTER
diag_printf( "---------DHCPSTATE_REBINDING sending:\n" );