net: ipv6: Add support for default gateway discovery.
In IPv6, the default gateway and prefix length are determined by receiving
a router advertisement as defined in -
https://www.rfc-editor.org/rfc/rfc4861.
Add support for sending router solicitation (RS) and processing router
advertisements (RA).
If the RA has prefix info option and following conditions are met, then
gatewayip6 and net_prefix_length of ip6addr env variables are initialized.
These are later consumed by IPv6 code for non-local destination IP.
- "Router Lifetime" != 0
- Prefix is NOT link-local prefix (0xfe80::/10)
- L flag is 1
- "Valid Lifetime" != 0
Timing Parameters:
- MAX_RTR_SOLICITATION_DELAY (0-1s)
- RTR_SOLICITATION_INTERVAL (4s) (min retransmit delay)
- MAX_RTR_SOLICITATIONS (3 RS transmissions)
The functionality is enabled by CONFIG_IPV6_ROUTER_DISCOVERY and invoked
automatically from net_init_loop().
Signed-off-by: Ehsan Mohandesi <emohandesi@linux.microsoft.com>
Tested-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>Reviewed-by:
Tested-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
Reviewed-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
Tested-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Sergei Antonov <saproj@gmail.com>
diff --git a/include/net6.h b/include/net6.h
index 2d7c5a0..beafc05 100644
--- a/include/net6.h
+++ b/include/net6.h
@@ -81,8 +81,17 @@
0x00, 0x00, 0x00, 0x00, \
0x00, 0x00, 0x00, 0x00, \
0x00, 0x00, 0x00, 0x00 } } }
+/*
+ * All-routers multicast address is the link-local scope address to reach all
+ * routers.
+ */
+#define ALL_ROUTERS_MULT_ADDR { { { 0xFF, 0x02, 0x00, 0x00, \
+ 0x00, 0x00, 0x00, 0x00, \
+ 0x00, 0x00, 0x00, 0x00, \
+ 0x00, 0x00, 0x00, 0x02 } } }
#define IPV6_LINK_LOCAL_PREFIX 0xfe80
+#define IPV6_LINK_LOCAL_MASK 0xffb0 /* The first 10-bit of address mask. */
/* hop limit for neighbour discovery packets */
#define IPV6_NDISC_HOPLIMIT 255
@@ -166,6 +175,37 @@
#define icmp6_rt_lifetime icmp6_dataun.u_nd_ra.rt_lifetime
} __packed;
+/*
+ * struct icmp6_ra_prefix_info - Prefix Information option of the ICMPv6 message
+ * The Prefix Information option provides hosts with on-link prefixes and
+ * prefixes for Address Autoconfiguration. Refer to RFC 4861 for more info.
+ */
+struct icmp6_ra_prefix_info {
+ u8 type; /* Type is 3 for Prefix Information. */
+ u8 len; /* Len is 4 for Prefix Information. */
+ /* The number of leading bits in the Prefix that are valid. */
+ u8 prefix_len;
+ u8 reserved1:6, /* MUST be ignored by the receiver. */
+ aac:1, /* autonomous address-configuration flag */
+ /* Indicates that this prefix can be used for on-link determination. */
+ on_link:1;
+ /*
+ * The length of time in seconds that the prefix is valid for the
+ * purpose of on-link determination.
+ */
+ __be32 valid_lifetime;
+ /* The length of time addresses remain preferred. */
+ __be32 preferred_lifetime;
+ __be32 reserved2; /* MUST be ignored by the receiver. */
+ /*
+ * Prefix is an IP address or a prefix of an IP address. The Prefix
+ * Length field contains the number of valid leading bits in the prefix.
+ * The bits in the prefix after the prefix length are reserved and MUST
+ * be initialized to zero by the sender and ignored by the receiver.
+ */
+ struct in6_addr prefix;
+};
+
extern struct in6_addr const net_null_addr_ip6; /* NULL IPv6 address */
extern struct in6_addr net_gateway6; /* Our gateways IPv6 address */
extern struct in6_addr net_ip6; /* Our IPv6 addr (0 = unknown) */