rtnetlink_socket = socket(AF_NETLINK, int socket_type, NETLINK_ROUTE);
struct rtattr {
unsigned short rta_len; /* Length of option */
unsigned short rta_type; /* Type of option */
/* Data follows */
};
These attributes should be manipulated using only the RTA_* macros or libnetlink, see rtnetlink(3).
struct ifinfomsg {
unsigned char ifi_family; /* AF_UNSPEC */
unsigned short ifi_type; /* Device type */
int ifi_index; /* Interface index */
unsigned int ifi_flags; /* Device flags */
unsigned int ifi_change; /* change mask */
};
ifi_flags contains the device flags, see netdevice(7); ifi_index is the unique interface index (since Linux 3.7, it is possible to feed a nonzero value with the RTM_NEWLINK message, thus creating a link with the given ifindex); ifi_change is reserved for future use and should be always set to 0xFFFFFFFF.
| Routing attributes | ||
| rta_type | value type | description |
| IFLA_UNSPEC | - | unspecified. |
| IFLA_ADDRESS | hardware address | interface L2 address |
| IFLA_BROADCAST | hardware address | L2 broadcast address. |
| IFLA_IFNAME | asciiz string | Device name. |
| IFLA_MTU | unsigned int | MTU of the device. |
| IFLA_LINK | int | Link type. |
| IFLA_QDISC | asciiz string | Queueing discipline. |
| IFLA_STATS | see below | Interface Statistics. |
The value type for IFLA_STATS is struct rtnl_link_stats (struct net_device_stats in Linux 2.4 and earlier).
struct ifaddrmsg {
unsigned char ifa_family; /* Address type */
unsigned char ifa_prefixlen; /* Prefixlength of address */
unsigned char ifa_flags; /* Address flags */
unsigned char ifa_scope; /* Address scope */
int ifa_index; /* Interface index */
};
ifa_family is the address family type (currently AF_INET or AF_INET6), ifa_prefixlen is the length of the address mask of the address if defined for the family (like for IPv4), ifa_scope is the address scope, ifa_index is the interface index of the interface the address is associated with. ifa_flags is a flag word of IFA_F_SECONDARY for secondary address (old alias interface), IFA_F_PERMANENT for a permanent address set by the user and other undocumented flags.
| Attributes | ||
| rta_type | value type | description |
| IFA_UNSPEC | - | unspecified. |
| IFA_ADDRESS | raw protocol address | interface address |
| IFA_LOCAL | raw protocol address | local address |
| IFA_LABEL | asciiz string | name of the interface |
| IFA_BROADCAST | raw protocol address | broadcast address. |
| IFA_ANYCAST | raw protocol address | anycast address |
| IFA_CACHEINFO | struct ifa_cacheinfo | Address information. |
struct rtmsg {
unsigned char rtm_family; /* Address family of route */
unsigned char rtm_dst_len; /* Length of destination */
unsigned char rtm_src_len; /* Length of source */
unsigned char rtm_tos; /* TOS filter */
unsigned char rtm_table; /* Routing table ID */
unsigned char rtm_protocol; /* Routing protocol; see below */
unsigned char rtm_scope; /* See below */
unsigned char rtm_type; /* See below */
unsigned int rtm_flags;
};
| rtm_type | Route type |
| RTN_UNSPEC | unknown route |
| RTN_UNICAST | a gateway or direct route |
| RTN_LOCAL | a local interface route |
| RTN_BROADCAST |
a local broadcast route (sent as a broadcast)
|
| RTN_ANYCAST |
a local broadcast route (sent as a unicast)
|
| RTN_MULTICAST | a multicast route |
| RTN_BLACKHOLE | a packet dropping route |
| RTN_UNREACHABLE | an unreachable destination |
| RTN_PROHIBIT | a packet rejection route |
| RTN_THROW | continue routing lookup in another table |
| RTN_NAT | a network address translation rule |
| RTN_XRESOLVE |
refer to an external resolver (not implemented)
|
| rtm_protocol | Route origin. |
| RTPROT_UNSPEC | unknown |
| RTPROT_REDIRECT |
by an ICMP redirect (currently unused)
|
| RTPROT_KERNEL | by the kernel |
| RTPROT_BOOT | during boot |
| RTPROT_STATIC | by the administrator |
Values larger than RTPROT_STATIC are not interpreted by the kernel, they are just for user information. They may be used to tag the source of a routing information or to distinguish between multiple routing daemons. See <linux/rtnetlink.h> for the routing daemon identifiers which are already assigned.
rtm_scope is the distance to the destination:
| RT_SCOPE_UNIVERSE | global route |
| RT_SCOPE_SITE |
interior route in the local autonomous system
|
| RT_SCOPE_LINK | route on this link |
| RT_SCOPE_HOST | route on the local host |
| RT_SCOPE_NOWHERE | destination doesn't exist |
The values between RT_SCOPE_UNIVERSE and RT_SCOPE_SITE are available to the user.
The rtm_flags have the following meanings:
| RTM_F_NOTIFY |
if the route changes, notify the user via rtnetlink
|
| RTM_F_CLONED | route is cloned from another route |
| RTM_F_EQUALIZE | a multipath equalizer (not yet implemented) |
rtm_table specifies the routing table
| RT_TABLE_UNSPEC | an unspecified routing table |
| RT_TABLE_DEFAULT | the default table |
| RT_TABLE_MAIN | the main table |
| RT_TABLE_LOCAL | the local table |
The user may assign arbitrary values between RT_TABLE_UNSPEC and RT_TABLE_DEFAULT.
| Attributes | ||
| rta_type | value type | description |
| RTA_UNSPEC | - | ignored. |
| RTA_DST | protocol address | Route destination address. |
| RTA_SRC | protocol address | Route source address. |
| RTA_IIF | int | Input interface index. |
| RTA_OIF | int | Output interface index. |
| RTA_GATEWAY | protocol address | The gateway of the route |
| RTA_PRIORITY | int | Priority of route. |
| RTA_PREFSRC | ||
| RTA_METRICS | int | Route metric |
| RTA_MULTIPATH | ||
| RTA_PROTOINFO | ||
| RTA_FLOW | ||
| RTA_CACHEINFO | ||
Fill these values in!
struct ndmsg {
unsigned char ndm_family;
int ndm_ifindex; /* Interface index */
__u16 ndm_state; /* State */
__u8 ndm_flags; /* Flags */
__u8 ndm_type;
};
struct nda_cacheinfo {
__u32 ndm_confirmed;
__u32 ndm_used;
__u32 ndm_updated;
__u32 ndm_refcnt;
};
ndm_state is a bit mask of the following states:
| NUD_INCOMPLETE | a currently resolving cache entry |
| NUD_REACHABLE | a confirmed working cache entry |
| NUD_STALE | an expired cache entry |
| NUD_DELAY | an entry waiting for a timer |
| NUD_PROBE | a cache entry that is currently reprobed |
| NUD_FAILED | an invalid cache entry |
| NUD_NOARP | a device with no destination cache |
| NUD_PERMANENT | a static entry |
Valid ndm_flags are:
| NTF_PROXY | a proxy arp entry |
| NTF_ROUTER | an IPv6 router |
The rtattr struct has the following meanings for the rta_type field:
| NDA_UNSPEC | unknown type |
| NDA_DST | a neighbor cache n/w layer destination address |
| NDA_LLADDR | a neighbor cache link layer address |
| NDA_CACHEINFO | cache statistics. |
If the rta_type field is NDA_CACHEINFO, then a struct nda_cacheinfo header follows
struct tcmsg {
unsigned char tcm_family;
int tcm_ifindex; /* interface index */
__u32 tcm_handle; /* Qdisc handle */
__u32 tcm_parent; /* Parent qdisc */
__u32 tcm_info;
};
| Attributes | ||
| rta_type | value type | Description |
| TCA_UNSPEC | - | unspecified |
| TCA_KIND | asciiz string | Name of queueing discipline |
| TCA_OPTIONS | byte sequence | Qdisc-specific options follow |
| TCA_STATS | struct tc_stats | Qdisc statistics. |
| TCA_XSTATS | qdisc-specific | Module-specific statistics. |
| TCA_RATE | struct tc_estimator | Rate limit. |
In addition, various other qdisc-module-specific attributes are allowed. For more information see the appropriate include files.