137 lines
3.5 KiB
ReStructuredText
137 lines
3.5 KiB
ReStructuredText
=====================
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Netlink Route support
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=====================
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Netlink Route (:c:macro:`NETLINK_ROUTE`) allow notifying msg when the network
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changes. And then apps can obtain these changes by monitoring to netlink socket
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messages.
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NuttX supports Netlink Route groups
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- RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE
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- Notify when IPV4|IPV6 routing table changes.
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- RTMGRP_NEIGH
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- Notify when ARP (IPV4) or neighbors (IPV6) table changes.
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- RTNLGRP_IPV6_PREFIX
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- Notify when IPV6 prefix changes.
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Messages content
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================
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1. RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE
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``RTM_NEWROUTE``, ``RTM_DELROUTE``, ``RTM_GETROUTE``:
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Create, remove or receive information about a network route. These
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messages contain an rtmsg structure with 3 optional sequence of
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rtattr structures following.
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.. code-block:: c
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struct getroute_recvfrom_ipv4addr_s
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{
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struct rtattr attr;
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in_addr_t addr;
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};
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struct getroute_recvfrom_ipv4response_s
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{
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struct nlmsghdr hdr;
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struct rtmsg rte;
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struct getroute_recvfrom_ipv4addr_s dst;
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struct getroute_recvfrom_ipv4addr_s genmask;
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struct getroute_recvfrom_ipv4addr_s gateway;
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};
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struct getroute_recvfrom_ipv6addr_s
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{
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struct rtattr attr;
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net_ipv6addr_t addr;
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};
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struct getroute_recvfrom_ipv6response_s
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{
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struct nlmsghdr hdr;
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struct rtmsg rte;
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struct getroute_recvfrom_ipv6addr_s dst;
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struct getroute_recvfrom_ipv6addr_s genmask;
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struct getroute_recvfrom_ipv6addr_s gateway;
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};
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2. RTMGRP_NEIGH
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``RTM_NEWNEIGH``, ``RTM_DELNEIGH``, ``RTM_GETNEIGH``:
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Add, remove or receive information about a neighbor table entry (e.g.,
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an ARP entry). The message contains an ndmsg structure and optional
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sequence of rtattr structures following. And the date will be ``struct arpreq``
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in ``include/netinet/arp.h``or ``struct neighbor_entry_s`` in ``include/net/neighbor.h``
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.. code-block:: c
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struct getneigh_recvfrom_response_s
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{
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struct nlmsghdr hdr;
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struct ndmsg msg;
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struct rtattr attr;
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uint8_t data[1];
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};
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3. RTNLGRP_IPV6_PREFIX
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``RTM_NEWPREFIX``:
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Receive information about IPV6 prefix. The message contains an prefixmsg structure
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and two optional sequence of rtattr structures following. And the ``addr`` and
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``prefix_cacheinfo`` are parsed from the RA message.
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.. code-block:: c
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struct getprefix_recvfrom_addr_s
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{
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struct rtattr attr;
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net_ipv6addr_t addr;
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};
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struct getprefix_recvfrom_cache_s
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{
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struct rtattr attr;
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struct prefix_cacheinfo pci;
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};
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struct getprefix_recvfrom_response_s
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{
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struct nlmsghdr hdr;
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struct prefixmsg pmsg;
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struct getprefix_recvfrom_addr_s prefix;
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struct getprefix_recvfrom_cache_s pci;
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};
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Usage
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=====
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.. code-block:: c
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struct sockaddr_nl addr;
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struct nlmsghdr *hdr;
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uint8_t buffer[BUFSIZE];
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int sd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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addr.nl_family = AF_NETLINK;
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addr.nl_groups = RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE |
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RTMGRP_NEIGH | RTMGRP_IPV6_PREFIX;
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bind(sd, (FAR struct sockaddr *)&addr, sizeof(addr)); /* Bind to device */
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while (1)
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{
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recv(sd, buf, BUFSIZE, 0);
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for (hdr = buf; NLMSG_OK(hdr, ret); hdr = NLMSG_NEXT(hdr, ret))
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{
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if (hdr->nlmsg_type == RTM_...)
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{
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/* Func parsed netlink msg*/
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...
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}
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}
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}
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close(sd); /* Close the socket */ |