Re: [PATCH] udhcpc6 source address is null, should be link-local address
Denys Vlasenko wrote: But what if interface has no IPv6 addresses? Isn't the whole purpose of DHCP is to *acquire an address*? For example, I don't use or need IPv6 for now. I just checked, and as expected, none of my interfaces have any IPv6 addresses. What should happen in this case? Does an iface absolutely need a link-local address (and how to acquire one?). If not, what dhcp client should fill in - all zeros? If yes, why can't it just always do that? From RFC 4862: link-local address - an address having link-only scope that can be used to reach neighboring nodes attached to the same link. All interfaces have a link-local unicast address. From RFC 4291: Links or Nodes with IEEE 802 48-bit MACs EUI64 defines a method to create an IEEE EUI-64 identifier from an IEEE 48-bit MAC identifier. This is to insert two octets, with hexadecimal values of 0xFF and 0xFE (see the Note at the end of appendix), in the middle of the 48-bit MAC (between the company_id and vendor-supplied id). An example is the 48-bit IEEE MAC with Global scope: |0 1|1 3|3 4| |0 5|6 1|2 7| ++++ |cc0g||| ++++ where c is the bits of the assigned company_id, 0 is the value of the universal/local bit to indicate Global scope, g is individual/group bit, and m is the bits of the manufacturer- selected extension identifier. The interface identifier would be of the form: |0 1|1 3|3 4|4 6| |0 5|6 1|2 7|8 3| +++++ |cc1g||1110|| +++++ When IEEE 802 48-bit MAC addresses are available (on an interface or a node), an implementation may use them to create interface identifiers due to their availability and uniqueness properties. ___ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
Re: [PATCH] udhcpc6 source address is null, should be link-local address
On Monday 19 August 2013 09:32, Mathias Krüger wrote: Okay, then here is the second try ;) $ patch -p1 /tmp/z.patch --dry-run patching file networking/udhcp/d6_common.h Hunk #1 FAILED at 91. 1 out of 1 hunk FAILED -- saving rejects to file networking/udhcp/d6_common.h.rej patching file networking/udhcp/d6_dhcpc.c patch: malformed patch at line 118: code) With some obvious line wrap fixes: $ patch -p1 /tmp/z.patch --dry-run patching file networking/udhcp/d6_common.h Hunk #1 FAILED at 91. 1 out of 1 hunk FAILED -- saving rejects to file networking/udhcp/d6_common.h.rej patching file networking/udhcp/d6_dhcpc.c Hunk #2 succeeded at 91 with fuzz 1. Hunk #3 FAILED at 344. Hunk #4 FAILED at 1034. Hunk #5 FAILED at 1142. 3 out of 5 hunks FAILED -- saving rejects to file networking/udhcp/d6_dhcpc.c.rej Usually people send patches as attachments if there are doubts whether their mail clients are able to not mangle patches. -- vda ___ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
Re: [PATCH] udhcpc6 source address is null, should be link-local address
On Monday 19 August 2013 09:32, Mathias Krüger wrote:
Okay, then here is the second try ;)
Here is a cleaned-up version of the patch (attached).
But what if interface has no IPv6 addresses?
Isn't the whole purpose of DHCP is to *acquire an address*?
For example, I don't use or need IPv6 for now.
I just checked, and as expected, none of my interfaces have
any IPv6 addresses.
What should happen in this case?
Does an iface absolutely need a link-local address (and how
to acquire one?).
If not, what dhcp client should fill in - all zeros?
If yes, why can't it just always do that?
I'm happy to see some people actually using udhcpc6
- it definitely needs to be finished and debugged,
which can be done only in real ipv6 environment.
--
vda
diff -ad -urpN busybox.0/networking/udhcp/d6_common.h busybox.1/networking/udhcp/d6_common.h
--- busybox.0/networking/udhcp/d6_common.h 2013-07-25 03:48:31.0 +0200
+++ busybox.1/networking/udhcp/d6_common.h 2013-08-20 22:54:29.0 +0200
@@ -91,6 +91,7 @@ struct client6_data_t {
struct d6_option *ia_na;
char **env_ptr;
unsigned env_idx;
+ struct in6_addr lladdr;
};
#define client6_data (*(struct client6_data_t*)(bb_common_bufsiz1[COMMON_BUFSIZE - sizeof(struct client6_data_t)]))
diff -ad -urpN busybox.0/networking/udhcp/d6_dhcpc.c busybox.1/networking/udhcp/d6_dhcpc.c
--- busybox.0/networking/udhcp/d6_dhcpc.c 2013-07-25 03:48:31.0 +0200
+++ busybox.1/networking/udhcp/d6_dhcpc.c 2013-08-20 22:58:29.0 +0200
@@ -34,6 +34,8 @@
#include netinet/if_ether.h
#include netpacket/packet.h
#include linux/filter.h
+#include net/if.h
+#include ifaddrs.h
/* struct client_config_t client_config is in bb_common_bufsiz1 */
@@ -89,6 +91,44 @@ enum {
/*** Utility functions ***/
+/* RFC 3315, section 16, says:
+ * The client MUST use a link-local address assigned to the interface for which
+ * it is requesting configuration information as the source address in the header
+ * of the IP datagram.
+ * - unlike DHCP for IPv4, where source ip if 0.0.0.0 is happily used.
+ * This helper reads link-local address for client_config.interface.
+ *
+ * TODO: what if interface has no IPv6 link-local address??
+ * For one, my ifaces definitely don't have any such addresses.
+ */
+static int d6_get_lladdr(void)
+{
+ struct sockaddr_in6 *our_ip6;
+ struct ifaddrs *ifap, *ife;
+
+ if (getifaddrs(ifap) 0)
+ goto err;
+
+ for (ife = ifap; ife; ife = ife-ifa_next) {
+ if (strcmp(client_config.interface, ife-ifa_name) != 0)
+ continue;
+ if (!ife-ifa_addr)
+ continue;
+ if (ife-ifa_addr-sa_family != AF_INET6)
+ continue;
+ our_ip6 = ((struct sockaddr_in6 *)ife-ifa_addr);
+ if (IN6_IS_ADDR_LINKLOCAL(our_ip6-sin6_addr)) {
+ client6_data.lladdr = our_ip6-sin6_addr;
+ freeifaddrs(ifap);
+ return 0;
+ }
+ }
+
+ err:
+ bb_error_msg(%s has no link-local address, client_config.interface);
+ return -1;
+}
+
static void *d6_find_option(uint8_t *option, uint8_t *option_end, unsigned code)
{
/* length minus 4 */
@@ -311,7 +351,7 @@ static int d6_mcast_from_client_config_i
return d6_send_raw_packet(
packet, (end - (uint8_t*) packet),
- /*src*/ NULL, CLIENT_PORT6,
+ /*src*/ client6_data.lladdr, CLIENT_PORT6,
/*dst*/ (struct in6_addr*)FF02__1_2, SERVER_PORT6, MAC_BCAST_ADDR,
client_config.ifindex
);
@@ -1001,6 +1041,8 @@ int udhcpc6_main(int argc UNUSED_PARAM,
) {
return 1;
}
+ if (d6_get_lladdr())
+ return 1;
/* Create client ID based on mac, set clientid_mac_ptr */
{
@@ -1104,6 +1146,8 @@ int udhcpc6_main(int argc UNUSED_PARAM,
) {
goto ret0; /* iface is gone? */
}
+ if (d6_get_lladdr())
+goto ret0; /* no link local address */
memcpy(clientid_mac_ptr, client_config.client_mac, 6);
/* We will restart the wait in any case */
diff -ad -urpN busybox.0/networking/udhcp/d6_packet.c busybox.1/networking/udhcp/d6_packet.c
--- busybox.0/networking/udhcp/d6_packet.c 2013-07-25 03:48:31.0 +0200
+++ busybox.1/networking/udhcp/d6_packet.c 2013-08-20 22:54:01.0 +0200
@@ -84,7 +84,7 @@ int FAST_FUNC d6_send_raw_packet(
}
packet.ip6.ip6_vfc = (6 4); /* 4 bits version, top 4 bits of tclass */
- if (src_ipv6)
+ /*if (src_ipv6) - always non-NULL*/
packet.ip6.ip6_src = *src_ipv6; /* struct copy */
packet.ip6.ip6_dst = *dst_ipv6; /* struct copy */
packet.udp.source = htons(source_port);
___
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Re: [PATCH] udhcpc6 source address is null, should be link-local address
On Tuesday 20 August 2013 23:12, Matt Whitlock wrote: On Tuesday, 20 August 2013, at 11:10 pm, Denys Vlasenko wrote: But what if interface has no IPv6 addresses? Isn't the whole purpose of DHCP is to *acquire an address*? Interfaces that support IPv6 addressing should automatically have IPv6 link-local addresses assigned by the kernel. This happens on every modern system I've ever used. If you're not seeing IPv6 link-local addresses on your interfaces, it's probably because your kernel does not support IPv6. If you have a modular kernel, try loading the ipv6 module. I manually configured one IPv6 address, on loopback: # ip a 1: lo: LOOPBACK,UP,1 mtu 65536 qdisc noqueue link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope hostTHIS ONE valid_lft forever preferred_lft forever 2: if: NO-CARRIER,BROADCAST,MULTICAST,UP mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:1d:7d:c2:ec:70 brd ff:ff:ff:ff:ff:ff inet 169.254.0.1/16 brd 169.254.255.255 scope global if inet 192.168.0.1/24 brd 192.168.0.255 scope global if 3: wifi0: BROADCAST,MULTICAST,UP,1 mtu 1500 qdisc pfifo_fast qlen 1000 link/ieee802.11 00:09:5b:69:17:c8 brd ff:ff:ff:ff:ff:ff 4: wlan0: BROADCAST,MULTICAST,UP,1 mtu 1500 qdisc noqueue link/ether 00:09:5b:69:17:c8 brd ff:ff:ff:ff:ff:ff inet 10.0.0.7/24 brd 10.0.0.255 scope global wlan0 As you see, other ifaces are up too but have no IPv6 addresses whatsoever. My kernel definitely has IPv6 enabled (non-modular): # grep IPV6 .config CONFIG_IPV6=y CONFIG_IPV6_PRIVACY=y CONFIG_IPV6_ROUTER_PREF=y CONFIG_IPV6_ROUTE_INFO=y # CONFIG_IPV6_OPTIMISTIC_DAD is not set CONFIG_IPV6_MIP6=m CONFIG_IPV6_SIT=m # CONFIG_IPV6_SIT_6RD is not set CONFIG_IPV6_NDISC_NODETYPE=y CONFIG_IPV6_TUNNEL=m # CONFIG_IPV6_GRE is not set # CONFIG_IPV6_MULTIPLE_TABLES is not set # CONFIG_IPV6_MROUTE is not set CONFIG_NF_DEFRAG_IPV6=m CONFIG_NF_CONNTRACK_IPV6=m CONFIG_IP6_NF_MATCH_IPV6HEADER=m CONFIG_NF_NAT_IPV6=m Anyway, from the kernel sources I see that IPv6 autoconfiguration can be disabled. Therefore, reradles of why my system doesn't do autoconfiguraion the question remains: what udhcpc6 should do in this case? -- vda ___ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
