/* rtnl - rtnetlink utility functions
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*
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* (C) 2004 by Astaro AG, written by Harald Welte <hwelte@astaro.com>
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*
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* Adapted to nfnetlink by Eric Leblond <eric@inl.fr>
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*
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* This software is free software and licensed under GNU GPLv2.
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*
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*/
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/* rtnetlink - routing table netlink interface */
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <time.h>
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <netinet/in.h>
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#include <linux/types.h>
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#include <sys/socket.h>
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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#include "rtnl.h"
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#define rtnl_log(x, ...)
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static inline struct rtnl_handler *
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find_handler(struct rtnl_handle *rtnl_handle, u_int16_t type)
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{
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struct rtnl_handler *h;
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for (h = rtnl_handle->handlers; h; h = h->next) {
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if (h->nlmsg_type == type)
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return h;
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}
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return NULL;
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}
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static int call_handler(struct rtnl_handle *rtnl_handle,
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u_int16_t type,
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struct nlmsghdr *hdr)
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{
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struct rtnl_handler *h = find_handler(rtnl_handle, type);
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if (!h) {
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rtnl_log(LOG_DEBUG, "no registered handler for type %u", type);
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return 0;
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}
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return (h->handlefn)(hdr, h->arg);
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}
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/* rtnl_handler_register - register handler for given nlmsg type
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* @hdlr: handler structure
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*/
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int rtnl_handler_register(struct rtnl_handle *rtnl_handle,
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struct rtnl_handler *hdlr)
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{
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rtnl_log(LOG_DEBUG, "registering handler for type %u",
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hdlr->nlmsg_type);
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hdlr->next = rtnl_handle->handlers;
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rtnl_handle->handlers = hdlr;
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return 1;
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}
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/* rtnl_handler_unregister - unregister handler for given nlmst type
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* @hdlr: handler structure
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*/
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int rtnl_handler_unregister(struct rtnl_handle *rtnl_handle,
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struct rtnl_handler *hdlr)
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{
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struct rtnl_handler *h, *prev = NULL;
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rtnl_log(LOG_DEBUG, "unregistering handler for type %u",
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hdlr->nlmsg_type);
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for (h = rtnl_handle->handlers; h; h = h->next) {
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if (h == hdlr) {
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if (prev)
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prev->next = h->next;
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else
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rtnl_handle->handlers = h->next;
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return 1;
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}
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prev = h;
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}
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return 0;
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}
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int rtnl_parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
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{
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memset(tb, 0, sizeof(struct rtattr *) * max);
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while (RTA_OK(rta, len)) {
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if (rta->rta_type <= max)
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tb[rta->rta_type] = rta;
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rta = RTA_NEXT(rta,len);
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}
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if (len)
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return -1;
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return 0;
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}
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/* rtnl_dump_type - ask rtnetlink to dump a specific table
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* @type: type of table to be dumped
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*/
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int rtnl_dump_type(struct rtnl_handle *rtnl_handle, unsigned int type)
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{
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struct {
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struct nlmsghdr nlh;
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struct rtgenmsg g;
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} req;
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struct sockaddr_nl nladdr;
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memset(&nladdr, 0, sizeof(nladdr));
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memset(&req, 0, sizeof(req));
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nladdr.nl_family = AF_NETLINK;
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req.nlh.nlmsg_len = sizeof(req);
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req.nlh.nlmsg_type = type;
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req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
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req.nlh.nlmsg_pid = 0;
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req.nlh.nlmsg_seq = rtnl_handle->rtnl_dump = ++(rtnl_handle->rtnl_seq);
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req.g.rtgen_family = AF_INET;
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return sendto(rtnl_handle->rtnl_fd, &req, sizeof(req), 0,
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(struct sockaddr*)&nladdr, sizeof(nladdr));
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}
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/* rtnl_receive - receive netlink packets from rtnetlink socket */
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int rtnl_receive(struct rtnl_handle *rtnl_handle)
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{
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int status;
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char buf[8192];
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struct sockaddr_nl nladdr;
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struct iovec iov = { buf, sizeof(buf) };
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struct nlmsghdr *h;
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struct msghdr msg = {
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.msg_name = &nladdr,
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.msg_namelen = sizeof(nladdr),
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.msg_iov = &iov,
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.msg_iovlen = 1,
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};
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status = recvmsg(rtnl_handle->rtnl_fd, &msg, 0);
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if (status < 0) {
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if (errno == EINTR)
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return 0;
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rtnl_log(LOG_NOTICE, "OVERRUN on rtnl socket");
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return -1;
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}
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if (status == 0) {
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rtnl_log(LOG_ERROR, "EOF on rtnl socket");
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return -1;
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}
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if (msg.msg_namelen != sizeof(nladdr)) {
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rtnl_log(LOG_ERROR, "invalid address size");
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return -1;
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}
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h = (struct nlmsghdr *) buf;
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while (NLMSG_OK(h, status)) {
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#if 0
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if (h->nlmsg_pid != rtnl_local.nl_pid ||
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h->nlmsg_seq != rtnl_dump) {
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goto skip;
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}
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#endif
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if (h->nlmsg_type == NLMSG_DONE) {
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rtnl_log(LOG_NOTICE, "NLMSG_DONE");
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return 0;
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}
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if (h->nlmsg_type == NLMSG_ERROR) {
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struct nlmsgerr *err = NLMSG_DATA(h);
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if (h->nlmsg_len>=NLMSG_LENGTH(sizeof(struct nlmsgerr)))
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errno = -err->error;
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rtnl_log(LOG_ERROR, "NLMSG_ERROR, errnp=%d",
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errno);
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return -1;
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}
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if (call_handler(rtnl_handle, h->nlmsg_type, h) == 0)
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rtnl_log(LOG_NOTICE, "unhandled nlmsg_type %u",
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h->nlmsg_type);
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h = NLMSG_NEXT(h, status);
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}
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return 1;
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}
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int rtnl_receive_multi(struct rtnl_handle *rtnl_handle)
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{
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while (1) {
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if (rtnl_receive(rtnl_handle) <= 0)
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break;
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}
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return 1;
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}
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/* rtnl_open - constructor of rtnetlink module */
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struct rtnl_handle *rtnl_open(void)
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{
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socklen_t addrlen;
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struct rtnl_handle *h;
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h = calloc(1, sizeof(struct rtnl_handle));
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if (!h)
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return NULL;
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addrlen = sizeof(h->rtnl_local);
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h->rtnl_local.nl_pid = getpid();
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h->rtnl_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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if (h->rtnl_fd < 0) {
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rtnl_log(LOG_ERROR, "unable to create rtnetlink socket");
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goto err;
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}
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memset(&h->rtnl_local, 0, sizeof(h->rtnl_local));
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h->rtnl_local.nl_family = AF_NETLINK;
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h->rtnl_local.nl_groups = RTMGRP_LINK;
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if (bind(h->rtnl_fd, (struct sockaddr *) &h->rtnl_local, addrlen) < 0) {
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rtnl_log(LOG_ERROR, "unable to bind rtnetlink socket");
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goto err_close;
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}
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if (getsockname(h->rtnl_fd,
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(struct sockaddr *) &h->rtnl_local,
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&addrlen) < 0) {
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rtnl_log(LOG_ERROR, "cannot gescockname(rtnl_socket)");
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goto err_close;
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}
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if (addrlen != sizeof(h->rtnl_local)) {
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rtnl_log(LOG_ERROR, "invalid address size %u", addr_len);
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goto err_close;
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}
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if (h->rtnl_local.nl_family != AF_NETLINK) {
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rtnl_log(LOG_ERROR, "invalid AF %u", h->rtnl_local.nl_family);
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goto err_close;
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}
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h->rtnl_seq = time(NULL);
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return h;
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err_close:
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close(h->rtnl_fd);
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err:
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free(h);
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return NULL;
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}
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/* rtnl_close - destructor of rtnetlink module */
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void rtnl_close(struct rtnl_handle *rtnl_handle)
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{
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close(rtnl_handle->rtnl_fd);
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free(rtnl_handle);
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return;
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}
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