static int
get_netlink(struct dhcpcd_ctx *ctx, struct iovec *iov,
    struct interface *ifp, int fd, int flags,
    int (*callback)(struct dhcpcd_ctx *, struct interface *, struct nlmsghdr *))
{
	struct msghdr msg;
	struct sockaddr_nl nladdr;
	ssize_t len;
	struct nlmsghdr *nlm;
	int r;
	unsigned int again;

	memset(&msg, 0, sizeof(msg));
	msg.msg_name = &nladdr;
	msg.msg_namelen = sizeof(nladdr);
	memset(&nladdr, 0, sizeof(nladdr));
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;
recv_again:
	if ((len = recvmsg_realloc(fd, &msg, flags)) == -1)
		return -1;
	if (len == 0)
		return 0;

	/* Check sender */
	if (msg.msg_namelen != sizeof(nladdr)) {
		errno = EINVAL;
		return -1;
	}
	/* Ignore message if it is not from kernel */
	if (nladdr.nl_pid != 0)
		return 0;

	r = 0;
	again = 0;	/* Appease static analysis */
	for (nlm = iov->iov_base;
	     nlm && NLMSG_OK(nlm, (size_t)len);
	     nlm = NLMSG_NEXT(nlm, len))
	{
		again = (nlm->nlmsg_flags & NLM_F_MULTI);
		if (nlm->nlmsg_type == NLMSG_NOOP)
			continue;
		if (nlm->nlmsg_type == NLMSG_ERROR) {
			struct nlmsgerr *err;

			if (nlm->nlmsg_len - sizeof(*nlm) < sizeof(*err)) {
				errno = EBADMSG;
				return -1;
			}
			err = (struct nlmsgerr *)NLMSG_DATA(nlm);
			if (err->error != 0) {
				errno = -err->error;
				return -1;
			}
			break;
		}
		if (nlm->nlmsg_type == NLMSG_DONE) {
			again = 0;
			break;
		}
		if (callback && (r = callback(ctx, ifp, nlm)) != 0)
			break;
	}

	if (r == 0 && again)
		goto recv_again;

	return r;
}

/*
 * Adds or deletes an IP address on an interface.
 *
 * Action is one of:
 * - RTM_NEWADDR (to add a new address)
 * - RTM_DELADDR (to delete an existing address)
 *
 * Returns zero on success and negative errno on failure.
 */
int ifc_act_on_address(int action, const char *name, const char *address,
                       int prefixlen) {
    int ifindex, s, len, ret;
    struct sockaddr_storage ss;
    void *addr;
    size_t addrlen;
    struct {
        struct nlmsghdr n;
        struct ifaddrmsg r;
        // Allow for IPv6 address, headers, and padding.
        char attrbuf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
                     NLMSG_ALIGN(sizeof(struct rtattr)) +
                     NLMSG_ALIGN(INET6_ADDRLEN)];
    } req;
    struct rtattr *rta;
    struct nlmsghdr *nh;
    struct nlmsgerr *err;
    char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
             NLMSG_ALIGN(sizeof(struct nlmsgerr)) +
             NLMSG_ALIGN(sizeof(struct nlmsghdr))];

    // Get interface ID.
    ifindex = if_nametoindex(name);
    if (ifindex == 0) {
        return -errno;
    }

    // Convert string representation to sockaddr_storage.
    ret = string_to_ip(address, &ss);
    if (ret) {
        return ret;
    }

    // Determine address type and length.
    if (ss.ss_family == AF_INET) {
        struct sockaddr_in *sin = (struct sockaddr_in *) &ss;
        addr = &sin->sin_addr;
        addrlen = INET_ADDRLEN;
    } else if (ss.ss_family == AF_INET6) {
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &ss;
        addr = &sin6->sin6_addr;
        addrlen = INET6_ADDRLEN;
    } else {
        return -EAFNOSUPPORT;
    }

    // Fill in netlink structures.
    memset(&req, 0, sizeof(req));

    // Netlink message header.
    req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.r));
    req.n.nlmsg_type = action;
    req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
    req.n.nlmsg_pid = getpid();

    // Interface address message header.
    req.r.ifa_family = ss.ss_family;
    req.r.ifa_prefixlen = prefixlen;
    req.r.ifa_index = ifindex;

    // Routing attribute. Contains the actual IP address.
    rta = (struct rtattr *) (((char *) &req) + NLMSG_ALIGN(req.n.nlmsg_len));
    rta->rta_type = IFA_LOCAL;
    rta->rta_len = RTA_LENGTH(addrlen);
    req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) + RTA_LENGTH(addrlen);
    memcpy(RTA_DATA(rta), addr, addrlen);

    s = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
    if (send(s, &req, req.n.nlmsg_len, 0) < 0) {
        close(s);
        return -errno;
    }

    len = recv(s, buf, sizeof(buf), 0);
    close(s);
    if (len < 0) {
        return -errno;
    }

    // Parse the acknowledgement to find the return code.
    nh = (struct nlmsghdr *) buf;
    if (!NLMSG_OK(nh, (unsigned) len) || nh->nlmsg_type != NLMSG_ERROR) {
        return -EINVAL;
    }
    err = NLMSG_DATA(nh);

    // Return code is negative errno.
    return err->error;
}

static void ipt_ulog_packet(unsigned int hooknum,
			    const struct sk_buff *skb,
			    const struct net_device *in,
			    const struct net_device *out,
			    const struct ipt_ulog_info *loginfo,
			    const char *prefix)
{
	ulog_buff_t *ub;
	ulog_packet_msg_t *pm;
	size_t size, copy_len;
	struct nlmsghdr *nlh;
	struct timeval tv;

	unsigned int groupnum = ffs(loginfo->nl_group) - 1;

	
	if (loginfo->copy_range == 0 || loginfo->copy_range > skb->len)
		copy_len = skb->len;
	else
		copy_len = loginfo->copy_range;

	size = NLMSG_SPACE(sizeof(*pm) + copy_len);

	ub = &ulog_buffers[groupnum];

	spin_lock_bh(&ulog_lock);

	if (!ub->skb) {
		if (!(ub->skb = ulog_alloc_skb(size)))
			goto alloc_failure;
	} else if (ub->qlen >= loginfo->qthreshold ||
		   size > skb_tailroom(ub->skb)) {

		ulog_send(groupnum);

		if (!(ub->skb = ulog_alloc_skb(size)))
			goto alloc_failure;
	}

	pr_debug("qlen %d, qthreshold %Zu\n", ub->qlen, loginfo->qthreshold);

	
	nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT,
			sizeof(*pm)+copy_len);
	ub->qlen++;

	pm = NLMSG_DATA(nlh);

	
	if (skb->tstamp.tv64 == 0)
		__net_timestamp((struct sk_buff *)skb);

	
	pm->data_len = copy_len;
	tv = ktime_to_timeval(skb->tstamp);
	put_unaligned(tv.tv_sec, &pm->timestamp_sec);
	put_unaligned(tv.tv_usec, &pm->timestamp_usec);
	put_unaligned(skb->mark, &pm->mark);
	pm->hook = hooknum;
	if (prefix != NULL)
		strncpy(pm->prefix, prefix, sizeof(pm->prefix));
	else if (loginfo->prefix[0] != '\0')
		strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix));
	else
		*(pm->prefix) = '\0';

	if (in && in->hard_header_len > 0 &&
	    skb->mac_header != skb->network_header &&
	    in->hard_header_len <= ULOG_MAC_LEN) {
		memcpy(pm->mac, skb_mac_header(skb), in->hard_header_len);
		pm->mac_len = in->hard_header_len;
	} else
		pm->mac_len = 0;

	if (in)
		strncpy(pm->indev_name, in->name, sizeof(pm->indev_name));
	else
		pm->indev_name[0] = '\0';

	if (out)
		strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name));
	else
		pm->outdev_name[0] = '\0';

	
	if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0)
		BUG();

	
	if (ub->qlen > 1)
		ub->lastnlh->nlmsg_flags |= NLM_F_MULTI;

	ub->lastnlh = nlh;

	
	if (!timer_pending(&ub->timer)) {
		ub->timer.expires = jiffies + flushtimeout * HZ / 100;
		add_timer(&ub->timer);
	}

//.........这里部分代码省略.........

/**
 * Process the message and add/drop multicast membership if needed
 */
int
ProcessInterfaceWatch(int s, int s_ssdp, int s_ssdp6,
                      int n_if_addr, const char * * if_addr)
{
	ssize_t len;
	int i;
	char buffer[4096];
#ifdef __linux__
	struct iovec iov;
	struct msghdr hdr;
	struct nlmsghdr *nlhdr;
	struct ifaddrmsg *ifa;

	iov.iov_base = buffer;
	iov.iov_len = sizeof(buffer);

	memset(&hdr, 0, sizeof(hdr));
	hdr.msg_iov = &iov;
	hdr.msg_iovlen = 1;

	len = recvmsg(s, &hdr, 0);
	if(len < 0) {
		syslog(LOG_ERR, "recvmsg(s, &hdr, 0): %m");
		return -1;
	}

	for(nlhdr = (struct nlmsghdr *)buffer;
		NLMSG_OK(nlhdr, len);
		nlhdr = NLMSG_NEXT(nlhdr, len)) {
		syslog(LOG_DEBUG, "nlmsg_type=%d", nlhdr->nlmsg_type);
		if(nlhdr->nlmsg_type == NLMSG_DONE)
			break;
		if(nlhdr->nlmsg_type == RTM_NEWADDR) {
			ifa = (struct ifaddrmsg *)NLMSG_DATA(nlhdr);
			syslog(LOG_DEBUG, "ProcessInterfaceWatchNotify RTM_NEWADDR index=%d", ifa->ifa_index);
			for(i = 0; i < n_if_addr; i++) {
				if(ifa->ifa_index == if_nametoindex(if_addr[i])) {
					AddDropMulticastMembership(s_ssdp, if_addr[i], 0, 0);
					break;
				}
			}
		} else if(nlhdr->nlmsg_type == RTM_DELADDR) {
			ifa = (struct ifaddrmsg *)NLMSG_DATA(nlhdr);
			syslog(LOG_DEBUG, "ProcessInterfaceWatchNotify RTM_DELADDR index=%d", ifa->ifa_index);
			for(i = 0; i < n_if_addr; i++) {
				if(ifa->ifa_index == if_nametoindex(if_addr[i])) {
					AddDropMulticastMembership(s_ssdp, if_addr[i], 0, 1);
					break;
				}
			}
		}
	}
#else /* __linux__ */
	struct rt_msghdr * rtm;
	struct ifa_msghdr * ifam;

	len = recv(s, buffer, sizeof(buffer), 0);
	if(len < 0) {
		syslog(LOG_ERR, "ProcessInterfaceWatchNotify recv: %m");
		return -1;
	}
	rtm = (struct rt_msghdr *)buffer;
	switch(rtm->rtm_type) {
	case RTM_NEWADDR:
		ifam = (struct ifa_msghdr *)buffer;
		syslog(LOG_DEBUG, "ProcessInterfaceWatchNotify RTM_NEWADDR index=%d", ifam->ifam_index);
		for(i = 0; i < n_if_addr; i++) {
			if(ifam->ifam_index == if_nametoindex(if_addr[i])) {
				AddDropMulticastMembership(s_ssdp, if_addr[i], 0, 0);
				break;
			}
		}
		break;
	case RTM_DELADDR:
		ifam = (struct ifa_msghdr *)buffer;
		syslog(LOG_DEBUG, "ProcessInterfaceWatchNotify RTM_DELADDR index=%d", ifam->ifam_index);
		for(i = 0; i < n_if_addr; i++) {
			if(ifam->ifam_index == if_nametoindex(if_addr[i])) {
				/* I dont think it is useful */
				/*AddDropMulticastMembership(s_ssdp, if_addr[i], 0, 1);*/
				break;
			}
		}
		break;
	default:
		syslog(LOG_DEBUG, "rtm->rtm_type=%d", rtm->rtm_type);
	}
#endif
	return 0;
}

static int interpretLink(struct nlmsghdr *p_hdr, struct ifaddrs **p_links, struct ifaddrs **p_resultList)
{
    struct ifinfomsg *l_info = (struct ifinfomsg *)NLMSG_DATA(p_hdr);

    size_t l_nameSize = 0;
    size_t l_addrSize = 0;
    size_t l_dataSize = 0;
    
    size_t l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifinfomsg));
    struct rtattr *l_rta;
    for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifinfomsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize))
    {
        void *l_rtaData = RTA_DATA(l_rta);
        size_t l_rtaDataSize = RTA_PAYLOAD(l_rta);
        switch(l_rta->rta_type)
        {
            case IFLA_ADDRESS:
            case IFLA_BROADCAST:
                l_addrSize += NLMSG_ALIGN(calcAddrLen(AF_PACKET, l_rtaDataSize));
                break;
            case IFLA_IFNAME:
                l_nameSize += NLMSG_ALIGN(l_rtaSize + 1);
                break;
            case IFLA_STATS:
                l_dataSize += NLMSG_ALIGN(l_rtaSize);
                break;
            default:
                break;
        }
    }
    
    struct ifaddrs *l_entry = malloc(sizeof(struct ifaddrs) + l_nameSize + l_addrSize + l_dataSize);
    if (l_entry == NULL)
    {
        return -1;
    }
    memset(l_entry, 0, sizeof(struct ifaddrs));
    l_entry->ifa_name = "";
    
    char *l_name = ((char *)l_entry) + sizeof(struct ifaddrs);
    char *l_addr = l_name + l_nameSize;
    char *l_data = l_addr + l_addrSize;
    
    l_entry->ifa_flags = l_info->ifi_flags;
    
    l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifinfomsg));
    for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifinfomsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize))
    {
        void *l_rtaData = RTA_DATA(l_rta);
        size_t l_rtaDataSize = RTA_PAYLOAD(l_rta);
        switch(l_rta->rta_type)
        {
            case IFLA_ADDRESS:
            case IFLA_BROADCAST:
            {
                size_t l_addrLen = calcAddrLen(AF_PACKET, l_rtaDataSize);
                makeSockaddr(AF_PACKET, (struct sockaddr *)l_addr, l_rtaData, l_rtaDataSize);
                ((struct sockaddr_ll *)l_addr)->sll_ifindex = l_info->ifi_index;
                ((struct sockaddr_ll *)l_addr)->sll_hatype = l_info->ifi_type;
                if(l_rta->rta_type == IFLA_ADDRESS)
                {
                    l_entry->ifa_addr = (struct sockaddr *)l_addr;
                }
                else
                {
                    l_entry->ifa_broadaddr = (struct sockaddr *)l_addr;
                }
                l_addr += NLMSG_ALIGN(l_addrLen);
                break;
            }
            case IFLA_IFNAME:
                strncpy(l_name, l_rtaData, l_rtaDataSize);
                l_name[l_rtaDataSize] = '\0';
                l_entry->ifa_name = l_name;
                break;
            case IFLA_STATS:
                memcpy(l_data, l_rtaData, l_rtaDataSize);
                l_entry->ifa_data = l_data;
                break;
            default:
                break;
        }
    }
    
    addToEnd(p_resultList, l_entry);
    p_links[l_info->ifi_index - 1] = l_entry;
    return 0;
}

int print_qdisc(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
{
	FILE *fp = (FILE*)arg;
	struct tcmsg *t = NLMSG_DATA(n);
	int len = n->nlmsg_len;
	struct rtattr * tb[TCA_MAX+1];
	struct qdisc_util *q;
	char abuf[256];

	if (n->nlmsg_type != RTM_NEWQDISC && n->nlmsg_type != RTM_DELQDISC) {
		fprintf(stderr, "Not a qdisc\n");
		return 0;
	}
	len -= NLMSG_LENGTH(sizeof(*t));
	if (len < 0) {
		fprintf(stderr, "Wrong len %d\n", len);
		return -1;
	}

	if (filter_ifindex && filter_ifindex != t->tcm_ifindex)
		return 0;

	memset(tb, 0, sizeof(tb));
	parse_rtattr(tb, TCA_MAX, TCA_RTA(t), len);

	if (tb[TCA_KIND] == NULL) {
		fprintf(stderr, "NULL kind\n");
		return -1;
	}

	if (n->nlmsg_type == RTM_DELQDISC)
		fprintf(fp, "deleted ");

	fprintf(fp, "qdisc %s %x: ", (char*)RTA_DATA(tb[TCA_KIND]), t->tcm_handle>>16);
	if (filter_ifindex == 0)
		fprintf(fp, "dev %s ", ll_index_to_name(t->tcm_ifindex));
	if (t->tcm_parent == TC_H_ROOT)
		fprintf(fp, "root ");
	else if (t->tcm_parent) {
		print_tc_classid(abuf, sizeof(abuf), t->tcm_parent);
		fprintf(fp, "parent %s ", abuf);
	}
	if (t->tcm_info != 1) {
		fprintf(fp, "refcnt %d ", t->tcm_info);
	}
	if ((q = get_qdisc_kind(RTA_DATA(tb[TCA_KIND]))) != NULL)
		q->print_qopt(q, fp, tb[TCA_OPTIONS]);
	else
		fprintf(fp, "[UNKNOWN]");
	fprintf(fp, "\n");
	if (show_stats) {
		if (tb[TCA_STATS]) {
			if (RTA_PAYLOAD(tb[TCA_STATS]) < sizeof(struct tc_stats))
				fprintf(fp, "statistics truncated");
			else {
				struct tc_stats st;
				memcpy(&st, RTA_DATA(tb[TCA_STATS]), sizeof(st));
				print_tcstats(fp, &st);
				fprintf(fp, "\n");
			}
		}
		if (q && tb[TCA_XSTATS]) {
			q->print_xstats(q, fp, tb[TCA_XSTATS]);
			fprintf(fp, "\n");
		}
		fprintf(fp, "\n ");
	}
	fflush(fp);
	return 0;
}

void read_ifaces(void)
{
	struct sockaddr_nl addr;
	socklen_t addr_len = sizeof(addr);
	unsigned char buffer[4096];
	int sock, len;

	struct { 
                struct nlmsghdr nlh;
                struct rtgenmsg g;
        }req;

	print_dbg(0, "Searching for network interfaces...\n");

        sock = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
        if (sock < 0) {
                perror("socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE) failed");
		exit(1);
	}

        memset(&addr, 0, sizeof(addr)); 
	addr.nl_family = AF_NETLINK;

	if (bind(sock, (struct sockaddr*)&addr, addr_len) < 0) {
		perror("bind(AF_NETLINK) failed");
		exit(1);
	}

	req.nlh.nlmsg_len = sizeof(req);
        req.nlh.nlmsg_type = RTM_GETLINK;
        req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_REQUEST;
        req.nlh.nlmsg_pid = 0;
        req.nlh.nlmsg_seq = 1;
        req.g.rtgen_family = AF_PACKET;

        if (sendto(sock, (void*)&req, sizeof(req), 0,
		   (struct sockaddr*)&addr, sizeof(addr)) < 0) {
		perror("inarpd: sendto(RTM_GETLINK) failed");
		exit(1);
	}

	while(1) {
		struct nlmsghdr *h = (struct nlmsghdr*)buffer;
		if ((len = recv(sock, buffer, sizeof(buffer), 0)) < 0) {
			perror("recv() failed");
			exit(1);
		}

		while (len > 0) {
			if (!NLMSG_OK(h, (unsigned) len)) {
				error("NLMSG 0x%X not OK\n", h->nlmsg_type);
				break;
			}

			print_dbg(2, "NLMSG 0x%X\n", h->nlmsg_type);

			if (h->nlmsg_type == RTM_NEWLINK)
				parse_link(NLMSG_DATA(h), IFLA_PAYLOAD(h));

			else if (h->nlmsg_type == RTM_NEWADDR)
				parse_addr(NLMSG_DATA(h), IFA_PAYLOAD(h));

			else if (h->nlmsg_type == NLMSG_DONE) {
				if (req.nlh.nlmsg_type == RTM_GETADDR) {
					close(sock);
					return;
				}
				req.nlh.nlmsg_type = RTM_GETADDR;
				if (sendto(sock, (void*)&req, sizeof(req), 0,
					   (struct sockaddr*)&addr,
					   sizeof(addr)) < 0) {
					perror("inarpd: sendto(RTM_GETADDR)"
					       " failed");
					exit(1);
				}
				break;

			} else
				error("Unknown netlink message type 0x%X\n",
				       h->nlmsg_type);

			h = NLMSG_NEXT(h, len);
		}
	}
}

int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
{
	FILE *fp = (FILE*)arg;
	struct rtmsg *r = NLMSG_DATA(n);
	int len = n->nlmsg_len;
	struct rtattr * tb[RTA_MAX+1];
	char abuf[256];
	int host_len;
	__u32 table;
	SPRINT_BUF(b1);
	static int hz;

	if (n->nlmsg_type != RTM_NEWROUTE && n->nlmsg_type != RTM_DELROUTE) {
		fprintf(stderr, "Not a route: %08x %08x %08x\n",
			n->nlmsg_len, n->nlmsg_type, n->nlmsg_flags);
		return 0;
	}
	if (filter.flushb && n->nlmsg_type != RTM_NEWROUTE)
		return 0;
	len -= NLMSG_LENGTH(sizeof(*r));
	if (len < 0) {
		fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
		return -1;
	}

	host_len = af_bit_len(r->rtm_family);

	parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
	table = rtm_get_table(r, tb);

	if (!filter_nlmsg(n, tb, host_len))
		return 0;

	if (filter.flushb) {
		struct nlmsghdr *fn;
		if (NLMSG_ALIGN(filter.flushp) + n->nlmsg_len > filter.flushe) {
			if (flush_update())
				return -1;
		}
		fn = (struct nlmsghdr*)(filter.flushb + NLMSG_ALIGN(filter.flushp));
		memcpy(fn, n, n->nlmsg_len);
		fn->nlmsg_type = RTM_DELROUTE;
		fn->nlmsg_flags = NLM_F_REQUEST;
		fn->nlmsg_seq = ++rth.seq;
		filter.flushp = (((char*)fn) + n->nlmsg_len) - filter.flushb;
		filter.flushed++;
		if (show_stats < 2)
			return 0;
	}

	if (n->nlmsg_type == RTM_DELROUTE)
		fprintf(fp, "Deleted ");
	if ((r->rtm_type != RTN_UNICAST || show_details > 0) && !filter.type)
		fprintf(fp, "%s ", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));

	if (tb[RTA_DST]) {
		if (r->rtm_dst_len != host_len) {
			fprintf(fp, "%s/%u ", rt_addr_n2a(r->rtm_family,
						       RTA_PAYLOAD(tb[RTA_DST]),
						       RTA_DATA(tb[RTA_DST]),
						       abuf, sizeof(abuf)),
				r->rtm_dst_len
				);
		} else {
			fprintf(fp, "%s ", format_host(r->rtm_family,
						       RTA_PAYLOAD(tb[RTA_DST]),
						       RTA_DATA(tb[RTA_DST]),
						       abuf, sizeof(abuf))
				);
		}
	} else if (r->rtm_dst_len) {
		fprintf(fp, "0/%d ", r->rtm_dst_len);
	} else {
		fprintf(fp, "default ");
	}
	if (tb[RTA_SRC]) {
		if (r->rtm_src_len != host_len) {
			fprintf(fp, "from %s/%u ", rt_addr_n2a(r->rtm_family,
						       RTA_PAYLOAD(tb[RTA_SRC]),
						       RTA_DATA(tb[RTA_SRC]),
						       abuf, sizeof(abuf)),
				r->rtm_src_len
				);
		} else {
			fprintf(fp, "from %s ", format_host(r->rtm_family,
						       RTA_PAYLOAD(tb[RTA_SRC]),
						       RTA_DATA(tb[RTA_SRC]),
						       abuf, sizeof(abuf))
				);
		}
	} else if (r->rtm_src_len) {
		fprintf(fp, "from 0/%u ", r->rtm_src_len);
	}
	if (tb[RTA_NEWDST]) {
		fprintf(fp, "as to %s ", format_host(r->rtm_family,
						  RTA_PAYLOAD(tb[RTA_NEWDST]),
						  RTA_DATA(tb[RTA_NEWDST]),
						  abuf, sizeof(abuf))
			);
	}
//.........这里部分代码省略.........

int
igs_cfg_request_send(igs_cfg_request_t *buffer, int length)
{
	struct sockaddr_nl src_addr, dest_addr;
	struct nlmsghdr *nlh = NULL;
	struct msghdr msg;
	struct iovec iov;
	int    sock_fd, ret;

	if ((buffer == NULL) || (length > MAX_DATA_SIZE))
	{
		fprintf(stderr, "Invalid parameters %p %d\n", buffer, length);
		return (FAILURE);
	}

	/* Create a netlink socket */
	sock_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_IGSC);

	if (sock_fd < 0)
	{
		fprintf(stderr, "Netlink socket create failed\n");
		return (FAILURE);
	}

	/* Associate a local address with the opened socket */
	memset(&src_addr, 0, sizeof(struct sockaddr_nl));
	src_addr.nl_family = AF_NETLINK;
	src_addr.nl_pid = getpid();
	src_addr.nl_groups = 0;
	bind(sock_fd, (struct sockaddr *)&src_addr, sizeof(src_addr));

	/* Fill the destination address, pid of 0 indicates kernel */
	memset(&dest_addr, 0, sizeof(struct sockaddr_nl));
	dest_addr.nl_family = AF_NETLINK;
	dest_addr.nl_pid = 0;
	dest_addr.nl_groups = 0;

	/* Allocate memory for sending configuration request */
	nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_DATA_SIZE));

	if (nlh == NULL)
	{
		fprintf(stderr, "Out of memory allocating cfg buffer\n");
		return (FAILURE);
	}

	/* Fill the netlink message header. The configuration request
	 * contains netlink header followed by data.
	 */
	nlh->nlmsg_len = NLMSG_SPACE(MAX_DATA_SIZE);
	nlh->nlmsg_pid = getpid();
	nlh->nlmsg_flags = 0;

	/* Fill the data part */
	memcpy(NLMSG_DATA(nlh), buffer, length);
	iov.iov_base = (void *)nlh;
	iov.iov_len = nlh->nlmsg_len;
	memset(&msg, 0, sizeof(struct msghdr));
	msg.msg_name = (void *)&dest_addr;
	msg.msg_namelen = sizeof(dest_addr);
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;

	/* Send request to kernel module */
	ret = sendmsg(sock_fd, &msg, 0);
	if (ret < 0)
	{
		perror("sendmsg:");
		free(nlh);
		return (ret);
	}

	/* Wait for the response */
	memset(nlh, 0, NLMSG_SPACE(MAX_DATA_SIZE));
	ret = recvmsg(sock_fd, &msg, 0);
	if (ret < 0)
	{
		perror("recvmsg:");
		free(nlh);
		return (ret);
	}

	/* Copy data to user buffer */
	memcpy(buffer, NLMSG_DATA(nlh), length);

	free(nlh);

	close(sock_fd);

	return (ret);
}

/*
 * Function     : handle_spectral_data
 * Description  : receive data from spectral driver
 * Input params : pointer to ath_ssdinfo
 * Return       : SUCCESS or FAILURE
 *
 */
int handle_spectral_data(ath_ssd_info_t *pinfo)
{

    ath_ssd_nlsock_t *pnl = GET_ADDR_OF_NLSOCKINFO(pinfo);
    ath_ssd_stats_t *pstats = GET_ADDR_OF_STATS(pinfo);
    struct nlmsghdr  *nlh = NULL;
    struct msghdr     msg;
    struct iovec      iov;
    int status = SUCCESS;
    int err = SUCCESS;
    int sockerr = 0;
    static int msg_pace_rate = 0;

    SPECTRAL_SAMP_MSG *ss_msg = NULL;
    SPECTRAL_SAMP_DATA  *ss_data = NULL;

    if (!(nlh = (struct nlmsghdr*)malloc(NLMSG_SPACE(sizeof(SPECTRAL_SAMP_MSG))))) {
        perror("no memory");
        status = FAILURE;
        return status;
    }

    memset(nlh, 0, NLMSG_SPACE(sizeof(SPECTRAL_SAMP_MSG)));
    nlh->nlmsg_len  = NLMSG_SPACE(sizeof(SPECTRAL_SAMP_MSG));
    nlh->nlmsg_pid  = getpid();
    nlh->nlmsg_flags = 0;

    iov.iov_base = (void *)nlh;
    iov.iov_len  = nlh->nlmsg_len;

    memset(&pnl->dst_addr, 0, sizeof(pnl->dst_addr));

    pnl->dst_addr.nl_family = PF_NETLINK;
    pnl->dst_addr.nl_pid    = 0;
    pnl->dst_addr.nl_groups = 1;

    memset(&msg, 0, sizeof(msg));
    msg.msg_name = (void*)&pnl->dst_addr;
    msg.msg_namelen = sizeof(pnl->dst_addr);
    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;

    /* receive spectral data from spectral driver */
    sockerr = recvmsg(pnl->spectral_fd, &msg, MSG_WAITALL);

    ss_msg = (SPECTRAL_SAMP_MSG*)NLMSG_DATA(nlh);
    ss_data = &ss_msg->samp_data;


    if (sockerr >= 0) {
        if (nlh->nlmsg_len) {
#ifdef  USE_OLD_CLASSIFIER
            process_spectral_msg(pinfo, ss_msg);
#else
            new_process_spectral_msg(pinfo, ss_msg);
#endif  /* USE_OLD_CLASSIFIER */
            msg_pace_rate++;
            if (msg_pace_rate == MSG_PACE_THRESHOLD) {
                send_to_client(pinfo, ss_msg, sizeof(SPECTRAL_SAMP_MSG));
                pstats->ch[pinfo->current_channel].sent_msg++;
                msg_pace_rate = 0;
            }

        }

        if (err == -1) {
            perror("send err");
            status = FAILURE;
        }
    } else if ((sockerr < 0) && (sockerr != EINTR))  {
        //perror("recvmsg");
    }

    /* free the resource */
    free(nlh);

    return status;
}

static int filter_nlmsg(struct nlmsghdr *n, struct rtattr **tb, int host_len)
{
	struct rtmsg *r = NLMSG_DATA(n);
	inet_prefix dst;
	inet_prefix src;
	inet_prefix via;
	inet_prefix prefsrc;
	__u32 table;
	static int ip6_multiple_tables;

	table = rtm_get_table(r, tb);

	if (preferred_family != AF_UNSPEC && r->rtm_family != preferred_family)
		return 0;

	if (r->rtm_family == AF_INET6 && table != RT_TABLE_MAIN)
		ip6_multiple_tables = 1;

	if (filter.cloned == !(r->rtm_flags&RTM_F_CLONED))
		return 0;

	if (r->rtm_family == AF_INET6 && !ip6_multiple_tables) {
		if (filter.tb) {
			if (filter.tb == RT_TABLE_LOCAL) {
				if (r->rtm_type != RTN_LOCAL)
					return 0;
			} else if (filter.tb == RT_TABLE_MAIN) {
				if (r->rtm_type == RTN_LOCAL)
					return 0;
			} else {
				return 0;
			}
		}
	} else {
		if (filter.tb > 0 && filter.tb != table)
			return 0;
	}
	if ((filter.protocol^r->rtm_protocol)&filter.protocolmask)
		return 0;
	if ((filter.scope^r->rtm_scope)&filter.scopemask)
		return 0;
	if ((filter.type^r->rtm_type)&filter.typemask)
		return 0;
	if ((filter.tos^r->rtm_tos)&filter.tosmask)
		return 0;
	if (filter.rdst.family &&
	    (r->rtm_family != filter.rdst.family || filter.rdst.bitlen > r->rtm_dst_len))
		return 0;
	if (filter.mdst.family &&
	    (r->rtm_family != filter.mdst.family ||
	     (filter.mdst.bitlen >= 0 && filter.mdst.bitlen < r->rtm_dst_len)))
		return 0;
	if (filter.rsrc.family &&
	    (r->rtm_family != filter.rsrc.family || filter.rsrc.bitlen > r->rtm_src_len))
		return 0;
	if (filter.msrc.family &&
	    (r->rtm_family != filter.msrc.family ||
	     (filter.msrc.bitlen >= 0 && filter.msrc.bitlen < r->rtm_src_len)))
		return 0;
	if (filter.rvia.family) {
		int family = r->rtm_family;
		if (tb[RTA_VIA]) {
			struct rtvia *via = RTA_DATA(tb[RTA_VIA]);
			family = via->rtvia_family;
		}
		if (family != filter.rvia.family)
			return 0;
	}
	if (filter.rprefsrc.family && r->rtm_family != filter.rprefsrc.family)
		return 0;

	memset(&dst, 0, sizeof(dst));
	dst.family = r->rtm_family;
	if (tb[RTA_DST])
		memcpy(&dst.data, RTA_DATA(tb[RTA_DST]), (r->rtm_dst_len+7)/8);
	if (filter.rsrc.family || filter.msrc.family) {
		memset(&src, 0, sizeof(src));
		src.family = r->rtm_family;
		if (tb[RTA_SRC])
			memcpy(&src.data, RTA_DATA(tb[RTA_SRC]), (r->rtm_src_len+7)/8);
	}
	if (filter.rvia.bitlen>0) {
		memset(&via, 0, sizeof(via));
		via.family = r->rtm_family;
		if (tb[RTA_GATEWAY])
			memcpy(&via.data, RTA_DATA(tb[RTA_GATEWAY]), host_len/8);
		if (tb[RTA_VIA]) {
			size_t len = RTA_PAYLOAD(tb[RTA_VIA]) - 2;
			struct rtvia *rtvia = RTA_DATA(tb[RTA_VIA]);
			via.family = rtvia->rtvia_family;
			memcpy(&via.data, rtvia->rtvia_addr, len);
		}
	}
	if (filter.rprefsrc.bitlen>0) {
		memset(&prefsrc, 0, sizeof(prefsrc));
		prefsrc.family = r->rtm_family;
		if (tb[RTA_PREFSRC])
			memcpy(&prefsrc.data, RTA_DATA(tb[RTA_PREFSRC]), host_len/8);
	}

//.........这里部分代码省略.........

static int
link_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp,
    struct nlmsghdr *nlm)
{
	int r;
	size_t len;
	struct rtattr *rta, *hwaddr;
	struct ifinfomsg *ifi;
	char ifn[IF_NAMESIZE + 1];

	r = link_route(ctx, ifp, nlm);
	if (r != 0)
		return r;
	r = link_addr(ctx, ifp, nlm);
	if (r != 0)
		return r;
#ifdef INET6
	r = link_neigh(ctx, ifp, nlm);
	if (r != 0)
		return r;
#endif

	if (nlm->nlmsg_type != RTM_NEWLINK && nlm->nlmsg_type != RTM_DELLINK)
		return 0;
	len = nlm->nlmsg_len - sizeof(*nlm);
	if ((size_t)len < sizeof(*ifi)) {
		errno = EBADMSG;
		return -1;
	}
	ifi = NLMSG_DATA(nlm);
	if (ifi->ifi_flags & IFF_LOOPBACK)
		return 0;
	rta = (void *)((char *)ifi + NLMSG_ALIGN(sizeof(*ifi)));
	len = NLMSG_PAYLOAD(nlm, sizeof(*ifi));
	*ifn = '\0';
	hwaddr = NULL;

	while (RTA_OK(rta, len)) {
		switch (rta->rta_type) {
		case IFLA_WIRELESS:
			/* Ignore wireless messages */
			if (nlm->nlmsg_type == RTM_NEWLINK &&
			    ifi->ifi_change == 0)
				return 0;
			break;
		case IFLA_IFNAME:
			strlcpy(ifn, (char *)RTA_DATA(rta), sizeof(ifn));
			break;
		case IFLA_ADDRESS:
			hwaddr = rta;
			break;
		}
		rta = RTA_NEXT(rta, len);
	}

	if (nlm->nlmsg_type == RTM_DELLINK) {
		/* If are listening to a dev manager, let that remove
		 * the interface rather than the kernel. */
		if (dev_listening(ctx) < 1)
			dhcpcd_handleinterface(ctx, -1, ifn);
		return 0;
	}

	/* Virtual interfaces may not get a valid hardware address
	 * at this point.
	 * To trigger a valid hardware address pickup we need to pretend
	 * that that don't exist until they have one. */
	if (ifi->ifi_flags & IFF_MASTER && !hwaddr) {
		dhcpcd_handleinterface(ctx, -1, ifn);
		return 0;
	}

	/* Check for a new interface */
	ifp = if_findindex(ctx->ifaces, (unsigned int)ifi->ifi_index);
	if (ifp == NULL) {
		/* If are listening to a dev manager, let that announce
		 * the interface rather than the kernel. */
		if (dev_listening(ctx) < 1)
			dhcpcd_handleinterface(ctx, 1, ifn);
		return 0;
	}

	/* Handle interface being renamed */
	if (strcmp(ifp->name, ifn) != 0) {
		dhcpcd_handleinterface(ctx, -1, ifn);
		dhcpcd_handleinterface(ctx, 1, ifn);
		return 0;
	}

	/* Re-read hardware address and friends */
	if (!(ifi->ifi_flags & IFF_UP) && hwaddr) {
		uint8_t l;

		l = l2addr_len(ifi->ifi_type);
		if (hwaddr->rta_len == RTA_LENGTH(l))
			dhcpcd_handlehwaddr(ctx, ifn, RTA_DATA(hwaddr), l);
	}

	dhcpcd_handlecarrier(ctx,
	    ifi->ifi_flags & IFF_RUNNING ? LINK_UP : LINK_DOWN,
//.........这里部分代码省略.........

static int
link_addr(struct dhcpcd_ctx *ctx, struct interface *ifp, struct nlmsghdr *nlm)
{
	size_t len;
	struct rtattr *rta;
	struct ifaddrmsg *ifa;
	struct priv *priv;
#ifdef INET
	struct in_addr addr, net, brd;
#endif
#ifdef INET6
	struct in6_addr addr6;
#endif

	if (nlm->nlmsg_type != RTM_DELADDR && nlm->nlmsg_type != RTM_NEWADDR)
		return 0;

	len = nlm->nlmsg_len - sizeof(*nlm);
	if (len < sizeof(*ifa)) {
		errno = EBADMSG;
		return -1;
	}

	/* Ignore messages we sent. */
	priv = (struct priv*)ctx->priv;
	if (nlm->nlmsg_pid == priv->route_pid)
		return 0;

	ifa = NLMSG_DATA(nlm);
	if ((ifp = if_findindex(ctx->ifaces, ifa->ifa_index)) == NULL) {
		/* We don't know about the interface the address is for
		 * so it's not really an error */
		return 1;
	}
	rta = (struct rtattr *)IFA_RTA(ifa);
	len = NLMSG_PAYLOAD(nlm, sizeof(*ifa));
	switch (ifa->ifa_family) {
#ifdef INET
	case AF_INET:
		addr.s_addr = brd.s_addr = INADDR_ANY;
		inet_cidrtoaddr(ifa->ifa_prefixlen, &net);
		while (RTA_OK(rta, len)) {
			switch (rta->rta_type) {
			case IFA_ADDRESS:
				if (ifp->flags & IFF_POINTOPOINT) {
					memcpy(&brd.s_addr, RTA_DATA(rta),
					    sizeof(brd.s_addr));
				}
				break;
			case IFA_BROADCAST:
				memcpy(&brd.s_addr, RTA_DATA(rta),
				    sizeof(brd.s_addr));
				break;
			case IFA_LOCAL:
				memcpy(&addr.s_addr, RTA_DATA(rta),
				    sizeof(addr.s_addr));
				break;
			}
			rta = RTA_NEXT(rta, len);
		}
		ipv4_handleifa(ctx, nlm->nlmsg_type, NULL, ifp->name,
		    &addr, &net, &brd, ifa->ifa_flags, (pid_t)nlm->nlmsg_pid);
		break;
#endif
#ifdef INET6
	case AF_INET6:
		memset(&addr6, 0, sizeof(addr6));
		while (RTA_OK(rta, len)) {
			switch (rta->rta_type) {
			case IFA_ADDRESS:
				memcpy(&addr6.s6_addr, RTA_DATA(rta),
				       sizeof(addr6.s6_addr));
				break;
			}
			rta = RTA_NEXT(rta, len);
		}
		ipv6_handleifa(ctx, nlm->nlmsg_type, NULL, ifp->name,
		    &addr6, ifa->ifa_prefixlen, ifa->ifa_flags,
		    (pid_t)nlm->nlmsg_pid);
		break;
#endif
	}
	return 0;
}

static int
if_copyrt(struct dhcpcd_ctx *ctx, struct rt *rt, struct nlmsghdr *nlm)
{
	size_t len;
	struct rtmsg *rtm;
	struct rtattr *rta;
	unsigned int ifindex;
	struct sockaddr *sa;

	len = nlm->nlmsg_len - sizeof(*nlm);
	if (len < sizeof(*rtm)) {
		errno = EBADMSG;
		return -1;
	}
	rtm = (struct rtmsg *)NLMSG_DATA(nlm);
	if (rtm->rtm_table != RT_TABLE_MAIN)
		return -1;

	memset(rt, 0, sizeof(*rt));
	if (rtm->rtm_type == RTN_UNREACHABLE)
		rt->rt_flags |= RTF_REJECT;

	rta = (struct rtattr *)RTM_RTA(rtm);
	len = RTM_PAYLOAD(nlm);
	while (RTA_OK(rta, len)) {
		sa = NULL;
		switch (rta->rta_type) {
		case RTA_DST:
			sa = &rt->rt_dest;
			break;
		case RTA_GATEWAY:
			sa = &rt->rt_gateway;
			break;
		case RTA_PREFSRC:
			sa = &rt->rt_ifa;
			break;
		case RTA_OIF:
			ifindex = *(unsigned int *)RTA_DATA(rta);
			rt->rt_ifp = if_findindex(ctx->ifaces, ifindex);
			break;
		case RTA_PRIORITY:
			rt->rt_metric = *(unsigned int *)RTA_DATA(rta);
			break;
		case RTA_METRICS:
		{
			struct rtattr *r2;
			size_t l2;

			l2 = rta->rta_len;
			r2 = (struct rtattr *)RTA_DATA(rta);
			while (RTA_OK(r2, l2)) {
				switch (r2->rta_type) {
				case RTAX_MTU:
					rt->rt_mtu = *(unsigned int *)RTA_DATA(r2);
					break;
				}
				r2 = RTA_NEXT(r2, l2);
			}
			break;
		}
		}

		if (sa != NULL) {
			socklen_t salen;

			sa->sa_family = rtm->rtm_family;
			salen = sa_addrlen(sa);
			memcpy((char *)sa + sa_addroffset(sa), RTA_DATA(rta),
			    MIN(salen, RTA_PAYLOAD(rta)));
		}

		rta = RTA_NEXT(rta, len);
	}

	/* If no RTA_DST set the unspecified address for the family. */
	if (rt->rt_dest.sa_family == AF_UNSPEC)
		rt->rt_dest.sa_family = rtm->rtm_family;

	rt->rt_netmask.sa_family = rtm->rtm_family;
	sa_fromprefix(&rt->rt_netmask, rtm->rtm_dst_len);
	if (sa_is_allones(&rt->rt_netmask))
		rt->rt_flags |= RTF_HOST;

	#if 0
	if (rt->rtp_ifp == NULL && rt->src.s_addr != INADDR_ANY) {
		struct ipv4_addr *ap;

		/* For some reason the default route comes back with the
		 * loopback interface in RTA_OIF? Lets find it by
		 * preferred source address */
		if ((ap = ipv4_findaddr(ctx, &rt->src)))
			rt->iface = ap->iface;
	}
	#endif

	if (rt->rt_ifp == NULL) {
		errno = ESRCH;
		return -1;
	}
	return 0;
//.........这里部分代码省略.........

static int process_msg(const struct sockaddr_nl *who, struct nlmsghdr *n,
		       void *arg)
{
	FILE *fp = (FILE *) arg;
	struct genlmsghdr *ghdr;
	struct rtattr *attrs[TCP_METRICS_ATTR_MAX + 1], *a;
	int len = n->nlmsg_len;
	char abuf[256];
	inet_prefix daddr, saddr;
	int family, i, atype, stype, dlen = 0, slen = 0;

	if (n->nlmsg_type != genl_family)
		return -1;

	len -= NLMSG_LENGTH(GENL_HDRLEN);
	if (len < 0)
		return -1;

	ghdr = NLMSG_DATA(n);
	if (ghdr->cmd != TCP_METRICS_CMD_GET)
		return 0;

	parse_rtattr(attrs, TCP_METRICS_ATTR_MAX, (void *) ghdr + GENL_HDRLEN,
		     len);

	a = attrs[TCP_METRICS_ATTR_ADDR_IPV4];
	if (a) {
		if (f.daddr.family && f.daddr.family != AF_INET)
			return 0;
		memcpy(&daddr.data, RTA_DATA(a), 4);
		daddr.bytelen = 4;
		family = AF_INET;
		atype = TCP_METRICS_ATTR_ADDR_IPV4;
		dlen = RTA_PAYLOAD(a);
	} else {
		a = attrs[TCP_METRICS_ATTR_ADDR_IPV6];
		if (a) {
			if (f.daddr.family && f.daddr.family != AF_INET6)
				return 0;
			memcpy(&daddr.data, RTA_DATA(a), 16);
			daddr.bytelen = 16;
			family = AF_INET6;
			atype = TCP_METRICS_ATTR_ADDR_IPV6;
			dlen = RTA_PAYLOAD(a);
		} else
			return 0;
	}

	a = attrs[TCP_METRICS_ATTR_SADDR_IPV4];
	if (a) {
		if (f.saddr.family && f.saddr.family != AF_INET)
			return 0;
		memcpy(&saddr.data, RTA_DATA(a), 4);
		saddr.bytelen = 4;
		stype = TCP_METRICS_ATTR_SADDR_IPV4;
		slen = RTA_PAYLOAD(a);
	} else {
		a = attrs[TCP_METRICS_ATTR_SADDR_IPV6];
		if (a) {
			if (f.saddr.family && f.saddr.family != AF_INET6)
				return 0;
			memcpy(&saddr.data, RTA_DATA(a), 16);
			saddr.bytelen = 16;
			stype = TCP_METRICS_ATTR_SADDR_IPV6;
			slen = RTA_PAYLOAD(a);
		}
	}

	if (f.daddr.family && f.daddr.bitlen >= 0 &&
	    inet_addr_match(&daddr, &f.daddr, f.daddr.bitlen))
	       return 0;
	/* Only check for the source-address if the kernel supports it,
	 * meaning slen != 0.
	 */
	if (slen && f.saddr.family && f.saddr.bitlen >= 0 &&
	    inet_addr_match(&saddr, &f.saddr, f.saddr.bitlen))
		return 0;

	if (f.flushb) {
		struct nlmsghdr *fn;
		TCPM_REQUEST(req2, 128, TCP_METRICS_CMD_DEL, NLM_F_REQUEST);

		addattr_l(&req2.n, sizeof(req2), atype, &daddr.data,
			  daddr.bytelen);
		if (slen)
			addattr_l(&req2.n, sizeof(req2), stype, &saddr.data,
				  saddr.bytelen);

		if (NLMSG_ALIGN(f.flushp) + req2.n.nlmsg_len > f.flushe) {
			if (flush_update())
				return -1;
		}
		fn = (struct nlmsghdr *) (f.flushb + NLMSG_ALIGN(f.flushp));
		memcpy(fn, &req2.n, req2.n.nlmsg_len);
		fn->nlmsg_seq = ++grth.seq;
		f.flushp = (((char *) fn) + req2.n.nlmsg_len) - f.flushb;
		f.flushed++;
		if (show_stats < 2)
			return 0;
	}
//.........这里部分代码省略.........

int rtnl_dump_filter(struct rtnl_handle *rth,
		     int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
		     void *arg1,
		     int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
		     void *arg2)
{
	char	buf[8192];
	struct sockaddr_nl nladdr;
	struct iovec iov = { buf, sizeof(buf) };

	while (1) {
		int status;
		struct nlmsghdr *h;

		struct msghdr msg = {
			(void*)&nladdr, sizeof(nladdr),
			&iov,	1,
			NULL,	0,
			0
		};

		status = recvmsg(rth->fd, &msg, 0);

		if (status < 0) {
			if (errno == EINTR)
				continue;
			perror("OVERRUN");
			continue;
		}
		if (status == 0) {
			fprintf(stderr, "EOF on netlink\n");
			return -1;
		}
		if (msg.msg_namelen != sizeof(nladdr)) {
			fprintf(stderr, "sender address length == %d\n", msg.msg_namelen);
			exit(1);
		}

		h = (struct nlmsghdr*)buf;
		while (NLMSG_OK(h, status)) {
			int err;

			if (h->nlmsg_pid != rth->local.nl_pid ||
			    h->nlmsg_seq != rth->dump) {
				if (junk) {
					err = junk(&nladdr, h, arg2);
					if (err < 0)
						return err;
				}
				goto skip_it;
			}

			if (h->nlmsg_type == NLMSG_DONE)
				return 0;
			if (h->nlmsg_type == NLMSG_ERROR) {
				struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
				if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
					fprintf(stderr, "ERROR truncated\n");
				} else {
					errno = -err->error;
					perror("RTNETLINK answers");
				}
				return -1;
			}
			err = filter(&nladdr, h, arg1);
			if (err < 0)
				return err;

skip_it:
			h = NLMSG_NEXT(h, status);
		}
		if (msg.msg_flags & MSG_TRUNC) {
			fprintf(stderr, "Message truncated\n");
			continue;
		}
		if (status) {
			fprintf(stderr, "!!!Remnant of size %d\n", status);
			exit(1);
		}
	}
}

//.........这里部分代码省略.........
#ifdef DEBUG_NETWORK
                                reconnDebugPrint("%s: oldLinkState  = %d theValue = %d messageSent = %d\n", __FUNCTION__, oldLinkState, theValue, messageSent);  
#endif
                                if((oldLinkState != theValue) || (messageSent == FALSE))
                                {
                                    oldLinkState = theValue;
                                    /*
                                     * Send message to the master client informing it of the link transition.
                                     */
                                    memset(theResponsePktPtr, 0, sizeof(theResponsePkt