C++ RTA_OK函数代码示例

static void rtnl_print_route(struct nlmsghdr *hdr)
{
	struct rtmsg *rtm = NLMSG_DATA(hdr);
	uint32_t attrs_len = RTM_PAYLOAD(hdr);
	struct rtattr *attr = RTM_RTA(rtm);
	struct rta_cacheinfo *ci;
	int hz = get_user_hz();
	char addr_str[256];
	char flags[256];

	tprintf(" [ Route Family %d (%s%s%s)", rtm->rtm_family,
			colorize_start(bold),
			addr_family2str(rtm->rtm_family),
			colorize_end());
	tprintf(", Dst Len %d", rtm->rtm_dst_len);
	tprintf(", Src Len %d", rtm->rtm_src_len);
	tprintf(", ToS %d", rtm->rtm_tos);
	tprintf(", Table %d (%s%s%s)", rtm->rtm_table,
			colorize_start(bold),
			route_table2str(rtm->rtm_table),
			colorize_end());
	tprintf(", Proto %d (%s%s%s)", rtm->rtm_protocol,
			colorize_start(bold),
			route_proto2str(rtm->rtm_protocol),
			colorize_end());
	tprintf(", Scope %d (%s%s%s)", rtm->rtm_scope,
			colorize_start(bold),
			scope2str(rtm->rtm_scope),
			colorize_end());
	tprintf(", Type %d (%s%s%s)", rtm->rtm_type,
			colorize_start(bold),
			route_type2str(rtm->rtm_type),
			colorize_end());
	tprintf(", Flags 0x%x (%s%s%s) ]\n", rtm->rtm_flags,
			colorize_start(bold),
			flags2str(route_flags, rtm->rtm_flags, flags,
				sizeof(flags)),
			colorize_end());

	for (; RTA_OK(attr, attrs_len); attr = RTA_NEXT(attr, attrs_len)) {
		switch (attr->rta_type) {
		case RTA_DST:
			attr_fmt(attr, "Dst %s", addr2str(rtm->rtm_family,
				RTA_DATA(attr), addr_str, sizeof(addr_str)));
			break;
		case RTA_SRC:
			attr_fmt(attr, "Src %s", addr2str(rtm->rtm_family,
				RTA_DATA(attr), addr_str, sizeof(addr_str)));
			break;
		case RTA_IIF:
			attr_fmt(attr, "Iif %d", RTA_INT(attr));
			break;
		case RTA_OIF:
			attr_fmt(attr, "Oif %d", RTA_INT(attr));
			break;
		case RTA_GATEWAY:
			attr_fmt(attr, "Gateway %s", addr2str(rtm->rtm_family,
				RTA_DATA(attr), addr_str, sizeof(addr_str)));
			break;
		case RTA_PRIORITY:
			attr_fmt(attr, "Priority %u", RTA_UINT32(attr));
			break;
		case RTA_PREFSRC:
			attr_fmt(attr, "Pref Src %s", addr2str(rtm->rtm_family,
				RTA_DATA(attr), addr_str, sizeof(addr_str)));
			break;
		case RTA_MARK:
			attr_fmt(attr, "Mark 0x%x", RTA_UINT(attr));
			break;
		case RTA_FLOW:
			attr_fmt(attr, "Flow 0x%x", RTA_UINT(attr));
			break;
		case RTA_TABLE:
			attr_fmt(attr, "Table %d (%s%s%s)", RTA_UINT32(attr),
				colorize_start(bold),
				route_table2str(RTA_UINT32(attr)),
				colorize_end());
			break;
		case RTA_CACHEINFO:
			ci = RTA_DATA(attr);
			tprintf("\tA: Cache (");
			tprintf("expires(%ds)", ci->rta_expires / hz);
			tprintf(", error(%d)", ci->rta_error);
			tprintf(", users(%d)", ci->rta_clntref);
			tprintf(", used(%d)", ci->rta_used);
			tprintf(", last use(%ds)", ci->rta_lastuse / hz);
			tprintf(", id(%d)", ci->rta_id);
			tprintf(", ts(%d)", ci->rta_ts);
			tprintf(", ts age(%ds))", ci->rta_tsage);
			tprintf(", Len %lu\n", RTA_LEN(attr));
			break;
		}
	}
}

//.........这里部分代码省略.........
  case S5ATIPV6:
    return -1;
  case S5ATFQDN:
    memset(&hints, 0, sizeof(hints));
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_family = AF_INET;
    memcpy(host, &dest->fqdn, dest->len_fqdn);
    host[dest->len_fqdn] = '\0';
    error = getaddrinfo(host, NULL, &hints, &res0);
    if (error) {
      return -1;
    }
    for (res = res0; res; res = res->ai_next) {
      if (res->ai_family != AF_INET)
	continue;
      sin = (struct sockaddr_in *)res->ai_addr;
      memcpy(&ia, &(sin->sin_addr), sizeof(ia));
      found++; break;
    }
    freeaddrinfo(res0);
    if (!found)
      return -1;
    break;
  default:
    return -1;
  }

  memset(&rreq, 0, sizeof(rreq));

  rreq.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
  rreq.n.nlmsg_flags = NLM_F_REQUEST;
  rreq.n.nlmsg_type = RTM_GETROUTE;
  rreq.r.rtm_family = AF_INET;

  len = RTA_LENGTH(4);
  if (NLMSG_ALIGN(rreq.n.nlmsg_len) + len > sizeof(rreq))
    return(-1);
  rta = (struct rtattr*)((char *)&rreq.n + NLMSG_ALIGN(rreq.n.nlmsg_len));
  rta->rta_type = RTA_DST;
  rta->rta_len = len;
  memcpy(RTA_DATA(rta), &ia, 4);
  rreq.n.nlmsg_len = NLMSG_ALIGN(rreq.n.nlmsg_len) + len;
  rreq.r.rtm_dst_len = 32;  /* 32 bit */

  s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);

  memset(&nladdr, 0, sizeof(nladdr));
  nladdr.nl_family = AF_NETLINK;
  nladdr.nl_pid = 0;
  nladdr.nl_groups = 0;

  rreq.n.nlmsg_seq = seq = 9999;

  iov.iov_base = (void*)&rreq.n;
  iov.iov_len  = rreq.n.nlmsg_len;

  status = sendmsg(s, &msg, 0);

  if (status < 0) {
    /* perror("Cannot talk to rtnetlink"); */
    return -1;
  }

  pid = getpid();
  iov.iov_base = buf;
  do {
    iov.iov_len = sizeof(buf);
    status = recvmsg(s, &msg, 0);
    h = (struct nlmsghdr*)buf;
  } while (h->nlmsg_pid != pid || h->nlmsg_seq != seq);

  close(s);
  /*
  msg_out(norm,"nlmsg_pid: %d, nlmsg_seq: %d",
	  h->nlmsg_pid, h->nlmsg_seq);
  */
  len = h->nlmsg_len;
  r = NLMSG_DATA(buf);
  rta = RTM_RTA(r);
  while (RTA_OK(rta, len)) {
    if (rta->rta_type <= RTA_MAX)
      tb[rta->rta_type] = rta;
    rta = RTA_NEXT(rta,len);
  }
  /*
  if (tb[RTA_DST]) {
    inet_ntop(AF_INET, RTA_DATA(tb[RTA_DST]), str, sizeof(str));
    msg_out(norm, "DST %s", str);
  }
  if (tb[RTA_GATEWAY]) {
    inet_ntop(AF_INET, RTA_DATA(tb[RTA_GATEWAY]), str, sizeof(str));
    msg_out(norm, "GW %s", str);
  }
  */
  if (tb[RTA_OIF]) {
    d = RTA_DATA(tb[RTA_OIF]);
    return(get_ifconf(*d, ba));
  }
  return(-1);
}

static int process_nlmsg(struct nlmsghdr *n) {
    assert(n);

    if (n->nlmsg_type == RTM_NEWLINK || n->nlmsg_type == RTM_DELLINK) {
        /* A link appeared or was removed */

        struct ifinfomsg *ifi;
        ifi = NLMSG_DATA(n);

        if (ifi->ifi_family != AF_UNSPEC || (int) ifi->ifi_index != ifindex)
            return 0;
        
        if (n->nlmsg_type == RTM_DELLINK) {
            daemon_log(LOG_ERR, "Interface vanished.");
            return -1;
        }

        assert(n->nlmsg_type == RTM_NEWLINK);
        
        if ((ifi->ifi_flags & IFF_LOOPBACK) ||
            (ifi->ifi_flags & IFF_NOARP) ||
            ifi->ifi_type != ARPHRD_ETHER) {
            daemon_log(LOG_ERR, "Interface not suitable.");
            return -1;
        }

    } else if (n->nlmsg_type == RTM_NEWADDR || n->nlmsg_type == RTM_DELADDR) {

        /* An address was added or removed */

        struct rtattr *a = NULL;
        struct ifaddrmsg *ifa;
        int l;
        uint32_t address = 0;
        Address *i;
        
        ifa = NLMSG_DATA(n);

        if (ifa->ifa_family != AF_INET || (int) ifa->ifa_index != ifindex)
            return 0;

        l = NLMSG_PAYLOAD(n, sizeof(*ifa));
        a = IFLA_RTA(ifa);

        while(RTA_OK(a, l)) {

            switch(a->rta_type) {
                case IFA_LOCAL:
                case IFA_ADDRESS:
                    assert(RTA_PAYLOAD(a) == 4);
                    memcpy(&address, RTA_DATA(a), sizeof(uint32_t));
                    break;
            }
            
            a = RTA_NEXT(a, l);
        }

        if (!address || is_ll_address(address))
            return 0;

        for (i = addresses; i; i = i->addresses_next)
            if (i->address == address)
                break;

        if (n->nlmsg_type == RTM_DELADDR && i) {
            AVAHI_LLIST_REMOVE(Address, addresses, addresses, i);
            avahi_free(i);
        } if (n->nlmsg_type == RTM_NEWADDR && !i) {
            i = avahi_new(Address, 1);
            i->address = address;
            AVAHI_LLIST_PREPEND(Address, addresses, addresses, i);
        }
    }

    return 0;
}

static void interpretAddr(struct nlmsghdr *p_hdr, struct ifaddrs **p_links, struct ifaddrs **p_resultList)
{
    struct ifaddrmsg *l_info = (struct ifaddrmsg *)NLMSG_DATA(p_hdr);

    size_t l_nameSize = 0;
    size_t l_addrSize = 0;

    int l_addedNetmask = 0;

    size_t l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifaddrmsg));
    struct rtattr *l_rta;
    for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize))
    {
        size_t l_rtaDataSize = RTA_PAYLOAD(l_rta);
        if(l_info->ifa_family == AF_PACKET)
        {
            continue;
        }

        switch(l_rta->rta_type)
        {
            case IFA_ADDRESS:
            case IFA_LOCAL:
                if((l_info->ifa_family == AF_INET || l_info->ifa_family == AF_INET6) && !l_addedNetmask)
                { // make room for netmask
                    l_addrSize += NLMSG_ALIGN(calcAddrLen(l_info->ifa_family, l_rtaDataSize));
                    l_addedNetmask = 1;
                }
            case IFA_BROADCAST:
                l_addrSize += NLMSG_ALIGN(calcAddrLen(l_info->ifa_family, l_rtaDataSize));
                break;
            case IFA_LABEL:
                l_nameSize += NLMSG_ALIGN(l_rtaSize + 1);
                break;
            default:
                break;
        }
    }

    struct ifaddrs *l_entry = malloc(sizeof(struct ifaddrs) + l_nameSize + l_addrSize);
    memset(l_entry, 0, sizeof(struct ifaddrs));
    l_entry->ifa_name = p_links[l_info->ifa_index - 1]->ifa_name;

    char *l_name = ((char *)l_entry) + sizeof(struct ifaddrs);
    char *l_addr = l_name + l_nameSize;

    l_entry->ifa_flags = l_info->ifa_flags | p_links[l_info->ifa_index - 1]->ifa_flags;

    l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifaddrmsg));
    for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))); 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 IFA_ADDRESS:
            case IFA_BROADCAST:
            case IFA_LOCAL:
            {
                size_t l_addrLen = calcAddrLen(l_info->ifa_family, l_rtaDataSize);
                makeSockaddr(l_info->ifa_family, (struct sockaddr *)l_addr, l_rtaData, l_rtaDataSize);
                if(l_info->ifa_family == AF_INET6)
                {
                    if(IN6_IS_ADDR_LINKLOCAL((struct in6_addr *)l_rtaData) || IN6_IS_ADDR_MC_LINKLOCAL((struct in6_addr *)l_rtaData))
                    {
                        ((struct sockaddr_in6 *)l_addr)->sin6_scope_id = l_info->ifa_index;
                    }
                }

                if(l_rta->rta_type == IFA_ADDRESS)
                { // apparently in a point-to-point network IFA_ADDRESS contains the dest address and IFA_LOCAL contains the local address
                    if(l_entry->ifa_addr)
                    {
                        l_entry->ifa_dstaddr = (struct sockaddr *)l_addr;
                    }
                    else
                    {
                        l_entry->ifa_addr = (struct sockaddr *)l_addr;
                    }
                }
                else if(l_rta->rta_type == IFA_LOCAL)
                {
                    if(l_entry->ifa_addr)
                    {
                        l_entry->ifa_dstaddr = l_entry->ifa_addr;
                    }
                    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 IFA_LABEL:
                strncpy(l_name, l_rtaData, l_rtaDataSize);
                l_name[l_rtaDataSize] = '\0';
                l_entry->ifa_name = l_name;
                break;
//.........这里部分代码省略.........

/**
 * @brief Handle an RTM_NEWLINK message from the driver, generating the
 *        appropriate events from it.
 *
 * @param [in] state  the internal state for this instance
 * @param [in] hdr  the netlink message header; the length field has
 *                  already been validated
 * @param [in] payloadLen  the length of the payload (not including the
 *                         netlink header)
 */
static void wlanifLinkEventsHandleNewLink(wlanifLinkEventsHandle_t state,
                                          const struct nlmsghdr *hdr,
                                          u_int32_t payloadLen) {
    const struct ifinfomsg *ifaceInfo = NLMSG_DATA(hdr);

    size_t ifaceLen = NLMSG_ALIGN(sizeof(*ifaceInfo));
    if (payloadLen < ifaceLen) {
        dbgf(state->dbgModule, DBGERR, "%s: Malformed netlink payload "
                                       "length %u", __func__, payloadLen);
        return;
    }

    wlanif_band_e band =
        wlanifBSteerControlResolveBandFromSystemIndex(state->bsteerControlHandle,
                                                      ifaceInfo->ifi_index);
    if (wlanif_band_invalid == band) {
        dbgf(state->dbgModule, DBGDUMP,
             "%s: Received message from ifindex %u not managed by lbd",
             __func__, ifaceInfo->ifi_index);
        return;
    }

    const struct rtattr *attr = IFLA_RTA(ifaceInfo);
    const size_t RTATTR_LEN = RTA_ALIGN(sizeof(*attr));

    // This will keep track of the amount of data remaining in the payload
    // for the RT attributes.
    size_t attrLen = payloadLen - ifaceLen;

    // Iterate over all of the RT attributes, looking for a wireless one
    // and then dispatch to a separate function to parse the event.
    while (RTA_OK(attr, attrLen)) {
        const u_int8_t *data =
            ((const u_int8_t *) attr) + RTATTR_LEN;
        switch (attr->rta_type) {
            case IFLA_WIRELESS:
            {
                wlanifLinkEventsHandleIWEvent(state, data,
                                              attr->rta_len - RTATTR_LEN,
                                              band, ifaceInfo->ifi_index);
                break;
            }

            case IFLA_OPERSTATE:
            {
                wlanifLinkEventsHandleOperState(state, data,
                                                attr->rta_len - RTATTR_LEN,
                                                band, ifaceInfo->ifi_index);
                break;
            }

            default:
            {
                // Nop (other than a log)
                dbgf(state->dbgModule, DBGDUMP,
                     "%s: Unhandled attribute: type=%04x len=%u",
                     __func__, attr->rta_type, attr->rta_len);
                break;
            }
        }

        attr = RTA_NEXT(attr, attrLen);
    }

    if (attrLen != 0) {
        dbgf(state->dbgModule, DBGERR, "%s: Did not consume all attributes: %u bytes left",
             __func__, attrLen);
    }
}

static struct if_nameindex *
if_nameindex_netlink (void)
{
  struct netlink_handle nh = { 0, 0, 0, NULL, NULL };
  struct if_nameindex *idx = NULL;

  if (__no_netlink_support || __netlink_open (&nh) < 0)
    return NULL;


  /* Tell the kernel that we wish to get a list of all
     active interfaces.  Collect all data for every interface.  */
  if (__netlink_request (&nh, RTM_GETLINK) < 0)
    goto exit_free;

  /* Count the interfaces.  */
  unsigned int nifs = 0;
  for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
    {
      struct nlmsghdr *nlh;
      size_t size = nlp->size;

      if (nlp->nlh == NULL)
	continue;

      /* Walk through all entries we got from the kernel and look, which
         message type they contain.  */
      for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
	{
	  /* Check if the message is what we want.  */
	  if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
	    continue;

	  if (nlh->nlmsg_type == NLMSG_DONE)
	    break;		/* ok */

	  if (nlh->nlmsg_type == RTM_NEWLINK)
	    ++nifs;
	}
    }

  idx = malloc ((nifs + 1) * sizeof (struct if_nameindex));
  if (idx == NULL)
    {
    nomem:
      __set_errno (ENOBUFS);
      goto exit_free;
    }

  /* Add the interfaces.  */
  nifs = 0;
  for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
    {
      struct nlmsghdr *nlh;
      size_t size = nlp->size;

      if (nlp->nlh == NULL)
	continue;

      /* Walk through all entries we got from the kernel and look, which
         message type they contain.  */
      for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
	{
	  /* Check if the message is what we want.  */
	  if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
	    continue;

	  if (nlh->nlmsg_type == NLMSG_DONE)
	    break;		/* ok */

	  if (nlh->nlmsg_type == RTM_NEWLINK)
	    {
	      struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlh);
	      struct rtattr *rta = IFLA_RTA (ifim);
	      size_t rtasize = IFLA_PAYLOAD (nlh);

	      idx[nifs].if_index = ifim->ifi_index;

	      while (RTA_OK (rta, rtasize))
		{
		  char *rta_data = RTA_DATA (rta);
		  size_t rta_payload = RTA_PAYLOAD (rta);

		  if (rta->rta_type == IFLA_IFNAME)
		    {
		      idx[nifs].if_name = __strndup (rta_data, rta_payload);
		      if (idx[nifs].if_name == NULL)
			{
			  idx[nifs].if_index = 0;
			  if_freenameindex (idx);
			  idx = NULL;
			  goto nomem;
			}
		      break;
		    }

		  rta = RTA_NEXT (rta, rtasize);
		}

	      ++nifs;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
		}
	
		if(nbytes == 0)
			printf("EOF in netlink\n");

		nlp = (struct nlmsghdr*)(&reply_ptr[reply_len]);

		if (nlp->nlmsg_type == NLMSG_DONE)
		{
	// All data has been received.
	// Truncate the reply to exclude this message,
	// i.e. do not increase reply_len.
		break;
		}

		if (nlp->nlmsg_type == NLMSG_ERROR)
		{
		printf("Error in msg\n");
		exit(1);
		}

		reply_len += nbytes;
		counter -= nbytes;
	}

	/*======================================================*/
	bufsize = reply_len;
	// string to hold content of the route
	// table (i.e. one entry)
	// unsigned int flags;

	// outer loop: loops thru all the NETLINK
	// headers that also include the route entry
	// header
	nlp = (struct nlmsghdr *) buf;

	for(i= -1; NLMSG_OK(nlp, bufsize); nlp=NLMSG_NEXT(nlp, bufsize))
	{
	// 	// get route entry header
		rtp = (struct rtmsg *) NLMSG_DATA(nlp);
		// we are only concerned about the
		// tableId route table
		if(rtp->rtm_table != 254)
			continue;
		i++;
		// init all the strings
		bzero(&route[i], sizeof(struct RouteInfo));
		// flags = rtp->rtm_flags;
		// route[i].proto = rtp->rtm_protocol;

	// // inner loop: loop thru all the attributes of
	// // one route entry
		rtap = (struct rtattr *) RTM_RTA(rtp);
		rtl = RTM_PAYLOAD(nlp);
		for( ; RTA_OK(rtap, rtl); rtap = RTA_NEXT(rtap, rtl))
		{
			switch(rtap->rta_type)
			{
			// destination IPv4 address
				case RTA_DST:
					// count = 32 - rtp->rtm_dst_len;
					route[i].dstAddr = *(unsigned long *) RTA_DATA(rtap);
				break;
				case RTA_GATEWAY:
					route[i].gateWay = *(unsigned long *) RTA_DATA(rtap);
					//printf("gw:%s\t",inet_ntoa(route[i].gateWay));
				break;
				// // unique ID associated with the network
				// // interface
				case RTA_OIF:
					ifname(*((int *) RTA_DATA(rtap)),route[i].ifName);
					//printf( "ifname %s\n", route[i].ifName);
				break;
				default:
				break;
			}

		}
	} 
	

	
	for( j = 0; j<= i; j++)
	{

		if(strcmp(route[j].ifName, ifNameVar)==0)
		{
                   
			char ipbuf[INET_ADDRSTRLEN];	   
			char ipbuf2[INET_ADDRSTRLEN];	   
			inet_ntop(AF_INET, &route[j].dstAddr, ipbuf, INET_ADDRSTRLEN);
			inet_ntop(AF_INET, &route[j].gateWay, ipbuf2, INET_ADDRSTRLEN);
			sprintf(outputRouting, "%lu.%lu:%s:%s", (unsigned long) tv.tv_sec,(unsigned long) tv.tv_nsec, ipbuf ,ipbuf2);
			fprintf(fpRouting, "%s\n" ,outputRouting);
		}
	}
    fflush(fpRouting);
	// close(route_sock);
	return 0;
}

static void netlink_callback(AvahiNetlink *nl, struct nlmsghdr *n, void* userdata) {
    AvahiInterfaceMonitor *m = userdata;

    /* This routine is called for every RTNETLINK response packet */

    assert(m);
    assert(n);
    assert(m->osdep.netlink == nl);

    if (n->nlmsg_type == RTM_NEWLINK) {

        /* A new interface appeared or an existing one has been modified */

        struct ifinfomsg *ifinfomsg = NLMSG_DATA(n);
        AvahiHwInterface *hw;
        struct rtattr *a = NULL;
        size_t l;

        /* A (superfluous?) sanity check */
        if (ifinfomsg->ifi_family != AF_UNSPEC)
            return;

        /* Check whether there already is an AvahiHwInterface object
         * for this link, so that we can update its data. Note that
         * Netlink sends us an RTM_NEWLINK not only when a new
         * interface appears, but when it changes, too */

        if (!(hw = avahi_interface_monitor_get_hw_interface(m, ifinfomsg->ifi_index)))

            /* No object found, so let's create a new
             * one. avahi_hw_interface_new() will call
             * avahi_interface_new() internally twice for IPv4 and
             * IPv6, so there is no need for us to do that
             * ourselves */
            if (!(hw = avahi_hw_interface_new(m, (AvahiIfIndex) ifinfomsg->ifi_index)))
                return; /* OOM */

        /* Check whether the flags of this interface are OK for us */
        hw->flags_ok =
            (ifinfomsg->ifi_flags & IFF_UP) &&
            (!m->server->config.use_iff_running || (ifinfomsg->ifi_flags & IFF_RUNNING)) &&
            !(ifinfomsg->ifi_flags & IFF_LOOPBACK) &&
            (ifinfomsg->ifi_flags & IFF_MULTICAST) &&
            (m->server->config.allow_point_to_point || !(ifinfomsg->ifi_flags & IFF_POINTOPOINT));

        /* Handle interface attributes */
        l = NLMSG_PAYLOAD(n, sizeof(struct ifinfomsg));
        a = IFLA_RTA(ifinfomsg);

        while (RTA_OK(a, l)) {
            switch(a->rta_type) {
                case IFLA_IFNAME:

                    /* Fill in interface name */
                    avahi_free(hw->name);
                    hw->name = avahi_strndup(RTA_DATA(a), RTA_PAYLOAD(a));
                    break;

                case IFLA_MTU:

                    /* Fill in MTU */
                    assert(RTA_PAYLOAD(a) == sizeof(unsigned int));
                    hw->mtu = *((unsigned int*) RTA_DATA(a));
                    break;

                case IFLA_ADDRESS:

                    /* Fill in hardware (MAC) address */
                    hw->mac_address_size = RTA_PAYLOAD(a);
                    if (hw->mac_address_size > AVAHI_MAC_ADDRESS_MAX)
                        hw->mac_address_size = AVAHI_MAC_ADDRESS_MAX;

                    memcpy(hw->mac_address, RTA_DATA(a), hw->mac_address_size);
                    break;

                default:
                    ;
            }

            a = RTA_NEXT(a, l);
        }

        /* Check whether this interface is now "relevant" for us. If
         * it is Avahi will start to announce its records on this
         * interface and send out queries for subscribed records on
         * it */
        avahi_hw_interface_check_relevant(hw, AVAHI_MDNS);
        avahi_hw_interface_check_relevant(hw, AVAHI_LLMNR);

        /* Update any associated RRs of this interface. (i.e. the
         * _workstation._tcp record containing the MAC address) */
        avahi_hw_interface_update_rrs(hw, 0);

    } else if (n->nlmsg_type == RTM_DELLINK) {

        /* An interface has been removed */

        struct ifinfomsg *ifinfomsg = NLMSG_DATA(n);
        AvahiHwInterface *hw;

//.........这里部分代码省略.........

static void
get_if_prefix(struct nlmsghdr *nlm, int nlm_len, int request,
	      struct dhcp6_if *ifp)
{
	struct rtmsg *rtm = (struct rtmsg *)NLMSG_DATA(nlm);
	struct rtattr *rta;
	size_t rtasize, rtapayload;
	void *rtadata;
	struct ra_info *rainfo;
	char addr[64];

	if (rtm->rtm_family != AF_INET6 || nlm->nlmsg_type != request)
		return;

	if (!(rtm->rtm_flags & RTM_F_PREFIX)) 
		return;

	rtasize = NLMSG_PAYLOAD(nlm, nlm_len) - NLMSG_ALIGN(sizeof(*rtm));
	rta = (struct rtattr *) (((char *) NLMSG_DATA(nlm)) +
	      NLMSG_ALIGN(sizeof(*rtm)));
	if (!RTA_OK(rta, rtasize))
		return;
	rtadata = RTA_DATA(rta);
	rtapayload = RTA_PAYLOAD(rta);
	switch(rta->rta_type) {
	case RTA_OIF:
		break;
	default:
		break; 
	}
	switch (rta->rta_type) {	
	case RTA_DST:
		rainfo = (struct ra_info *)malloc(sizeof(*rainfo));
		if (rainfo == NULL)
			return;
		memset(rainfo, 0, sizeof(rainfo));
		memcpy(&(rainfo->prefix), (struct in6_addr *)rtadata, 
		       sizeof(struct in6_addr));
		rainfo->plen = rtm->rtm_dst_len;
		if (ifp->ralist == NULL) {
			ifp->ralist = rainfo;
			rainfo->next = NULL;
		} else {
			struct ra_info *ra, *ra_prev;
			ra_prev = ifp->ralist;
			for (ra = ifp->ralist; ra; ra = ra->next) {
				if (rainfo->plen >= ra->plen) {
					if (ra_prev == ra) {
						ifp->ralist = rainfo;
						rainfo->next = ra;
					} else {
						ra_prev->next = rainfo;
						rainfo->next = ra;
					}
					break;
				} else {
					if (ra->next == NULL) {
						ra->next = rainfo;
						rainfo->next = NULL;
						break;
					} else {
						ra_prev = ra;
						continue;
					}
				}
			}
		}
		inet_ntop(AF_INET6, &(rainfo->prefix), addr, INET6_ADDRSTRLEN);
		dprintf(LOG_DEBUG, "get prefix address %s", addr);
		dprintf(LOG_DEBUG, "get prefix plen %d",rtm->rtm_dst_len);
		break;
	case RTA_CACHEINFO:
		dprintf(LOG_DEBUG, "prefix route life time is %d\n",
		      ((struct rta_cacheinfo *)rtadata)->rta_expires);
		break;
	default:
		break;
	}
	return;
}

void process_nl_new_route (struct nlmsghdr *nlh)
{
    struct rtmsg             *rtm                       = NULL;
    struct rtattr            *rt_attr                   = NULL;
    int                      rt_length                  = 0;
    lispd_iface_elt          *iface                     = NULL;
    int                      iface_index                = 0;
    char                     iface_name[IF_NAMESIZE];
    lisp_addr_t              gateway                    = {.afi=AF_UNSPEC};
    lisp_addr_t              dst                        = {.afi=AF_UNSPEC};;


    rtm = (struct rtmsg *) NLMSG_DATA (nlh);

    if ((rtm->rtm_family != AF_INET) && (rtm->rtm_family != AF_INET6)) {
        lispd_log_msg(LISP_LOG_DEBUG_2,"process_nl_new_route: Unknown adddress family");
        return;
    }

    if (rtm->rtm_table != RT_TABLE_MAIN) {
        /* Not interested in routes/gateways affecting tables other the main routing table */
        return;
    }

    rt_attr = (struct rtattr *)RTM_RTA(rtm);
    rt_length = RTM_PAYLOAD(nlh);

    for (; RTA_OK(rt_attr, rt_length); rt_attr = RTA_NEXT(rt_attr, rt_length)) {
        switch (rt_attr->rta_type) {
        case RTA_OIF:
            iface_index = *(int *)RTA_DATA(rt_attr);
            iface = get_interface_from_index(iface_index);
            if_indextoname(iface_index, iface_name);
            if (iface == NULL) {
                lispd_log_msg(LISP_LOG_DEBUG_2, "process_nl_new_route: the netlink message is not for any interface associated with RLOCs (%s)",
                              iface_name);
                return;
            }
            break;
        case RTA_GATEWAY:
            gateway.afi = rtm->rtm_family;
            switch (gateway.afi) {
            case AF_INET:
                memcpy(&(gateway.address),(struct in_addr *)RTA_DATA(rt_attr), sizeof(struct in_addr));
                break;
            case AF_INET6:
                memcpy(&(gateway.address),(struct in6_addr *)RTA_DATA(rt_attr), sizeof(struct in6_addr));
                break;
            default:
                break;
            }
            break;
        case RTA_DST: // We check if the new route message contains a destintaion. If it is, then the gateway address is not a default route. Discard it
            dst.afi = rtm->rtm_family;
            switch (dst.afi) {
            case AF_INET:
                memcpy(&(dst.address),(struct in_addr *)RTA_DATA(rt_attr), sizeof(struct in_addr));
                break;
            case AF_INET6:
                memcpy(&(dst.address),(struct in6_addr *)RTA_DATA(rt_attr), sizeof(struct in6_addr));
                break;
            default:
                break;
            }
            break;
        default:
            break;
        }
    }
    if (gateway.afi != AF_UNSPEC && iface_index != 0 && dst.afi == AF_UNSPEC) {
        /* Check default afi*/
        if (default_rloc_afi != AF_UNSPEC && default_rloc_afi != gateway.afi) {
            lispd_log_msg(LISP_LOG_DEBUG_1,  "process_nl_new_route: Default RLOC afi defined (-a #): Skipped %s gateway in iface %s",
                          (gateway.afi == AF_INET) ? "IPv4" : "IPv6",iface->iface_name);
            return;
        }

        /* Check if the addres is a global address*/
        if (is_link_local_addr(gateway) == TRUE) {
            lispd_log_msg(LISP_LOG_DEBUG_2,"process_nl_new_route: the extractet address from the netlink "
                          "messages is a local link address: %s discarded", get_char_from_lisp_addr_t(gateway));
            return;
        }

        /* Process the new gateway */
        lispd_log_msg(LISP_LOG_DEBUG_1,  "process_nl_new_route: Process new gateway associated to the interface %s:  %s",
                      iface_name, get_char_from_lisp_addr_t(gateway));
        process_new_gateway(gateway,iface);
    }
}

static NOINLINE int check_existence_through_netlink(void)
{
	int iface_len;
	/* Buffer was 1K, but on linux-3.9.9 it was reported to be too small.
	 * netlink.h: "limit to 8K to avoid MSG_TRUNC when PAGE_SIZE is very large".
	 * Note: on error returns (-1) we exit, no need to free replybuf.
	 */
	enum { BUF_SIZE = 8 * 1024 };
	char *replybuf = xmalloc(BUF_SIZE);

	iface_len = strlen(G.iface);
	while (1) {
		struct nlmsghdr *mhdr;
		ssize_t bytes;

		bytes = recv(netlink_fd, replybuf, BUF_SIZE, MSG_DONTWAIT);
		if (bytes < 0) {
			if (errno == EAGAIN)
				goto ret;
			if (errno == EINTR)
				continue;
			bb_perror_msg("netlink: recv");
			return -1;
		}

		mhdr = (struct nlmsghdr*)replybuf;
		while (bytes > 0) {
			if (!NLMSG_OK(mhdr, bytes)) {
				bb_error_msg("netlink packet too small or truncated");
				return -1;
			}

			if (mhdr->nlmsg_type == RTM_NEWLINK || mhdr->nlmsg_type == RTM_DELLINK) {
				struct rtattr *attr;
				int attr_len;

				if (mhdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifinfomsg))) {
					bb_error_msg("netlink packet too small or truncated");
					return -1;
				}

				attr = IFLA_RTA(NLMSG_DATA(mhdr));
				attr_len = IFLA_PAYLOAD(mhdr);

				while (RTA_OK(attr, attr_len)) {
					if (attr->rta_type == IFLA_IFNAME) {
						int len = RTA_PAYLOAD(attr);
						if (len > IFNAMSIZ)
							len = IFNAMSIZ;
						if (iface_len <= len
						 && strncmp(G.iface, RTA_DATA(attr), len) == 0
						) {
							G.iface_exists = (mhdr->nlmsg_type == RTM_NEWLINK);
						}
					}
					attr = RTA_NEXT(attr, attr_len);
				}
			}

			mhdr = NLMSG_NEXT(mhdr, bytes);
		}
	}

 ret:
	free(replybuf);
	return G.iface_exists;
}

static __inline__ int
rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
{
	struct rtnetlink_link *link;
	struct rtnetlink_link *link_tab;
	struct rtattr	*rta[RTATTR_MAX];

	int exclusive = 0;
	int sz_idx, kind;
	int min_len;
	int family;
	int type;
	int err;

	/* Only requests are handled by kernel now */
	if (!(nlh->nlmsg_flags&NLM_F_REQUEST))
		return 0;

	type = nlh->nlmsg_type;

	/* A control message: ignore them */
	if (type < RTM_BASE)
		return 0;

	/* Unknown message: reply with EINVAL */
	if (type > RTM_MAX)
		goto err_inval;

	type -= RTM_BASE;

	/* All the messages must have at least 1 byte length */
	if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtgenmsg)))
		return 0;

	family = ((struct rtgenmsg*)NLMSG_DATA(nlh))->rtgen_family;
	if (family > NPROTO) {
		*errp = -EAFNOSUPPORT;
		return -1;
	}

	link_tab = rtnetlink_links[family];
	if (link_tab == NULL)
		link_tab = rtnetlink_links[PF_UNSPEC];
	link = &link_tab[type];

	sz_idx = type>>2;
	kind = type&3;

	if (kind != 2 && !cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) {
		*errp = -EPERM;
		return -1;
	}

	if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
		u32 rlen;

		if (link->dumpit == NULL)
			link = &(rtnetlink_links[PF_UNSPEC][type]);

		if (link->dumpit == NULL)
			goto err_inval;

		if ((*errp = netlink_dump_start(rtnl, skb, nlh,
						link->dumpit,
						rtnetlink_done)) != 0) {
			return -1;
		}
		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
		if (rlen > skb->len)
			rlen = skb->len;
		skb_pull(skb, rlen);
		return -1;
	}

	if (kind != 2) {
		if (rtnl_exlock_nowait()) {
			*errp = 0;
			return -1;
		}
		exclusive = 1;
	}

	memset(&rta, 0, sizeof(rta));

	min_len = rtm_min[sz_idx];
	if (nlh->nlmsg_len < min_len)
		goto err_inval;

	if (nlh->nlmsg_len > min_len) {
		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
		struct rtattr *attr = (void*)nlh + NLMSG_ALIGN(min_len);

		while (RTA_OK(attr, attrlen)) {
			unsigned flavor = attr->rta_type;
			if (flavor) {
				if (flavor > rta_max[sz_idx])
					goto err_inval;
				rta[flavor-1] = attr;
			}
			attr = RTA_NEXT(attr, attrlen);
//.........这里部分代码省略.........

static void rtnl_print_neigh(struct nlmsghdr *hdr)
{
	struct ndmsg *ndm = NLMSG_DATA(hdr);
	uint32_t attrs_len = NDA_PAYLOAD(hdr);
	struct rtattr *attr = NDA_RTA(ndm);
	struct nda_cacheinfo *ci;
	int hz = get_user_hz();
	char addr_str[256];
	char hw_addr[30];
	char states[256];
	char flags[256];

	tprintf(" [ Neigh Family %d (%s%s%s)", ndm->ndm_family,
			colorize_start(bold),
			addr_family2str(ndm->ndm_family),
			colorize_end());
	tprintf(", Link Index %d", ndm->ndm_ifindex);
	tprintf(", State %d (%s%s%s)", ndm->ndm_state,
			colorize_start(bold),
			flags2str(neigh_states, ndm->ndm_state, states,
				sizeof(states)),
			colorize_end());
	tprintf(", Flags %d (%s%s%s)", ndm->ndm_flags,
			colorize_start(bold),
			flags2str(neigh_flags, ndm->ndm_flags, flags,
				sizeof(flags)),
			colorize_end());
	tprintf(", Type %d (%s%s%s)", ndm->ndm_type,
			colorize_start(bold),
			route_type2str(ndm->ndm_type),
			colorize_end());
	tprintf(" ]\n");

	for (; RTA_OK(attr, attrs_len); attr = RTA_NEXT(attr, attrs_len)) {
		switch (attr->rta_type) {
		case NDA_DST:
			attr_fmt(attr, "Address %s", addr2str(ndm->ndm_family,
						RTA_DATA(attr), addr_str,
						sizeof(addr_str)));
			break;
		case NDA_LLADDR:
			attr_fmt(attr, "HW Address %s",
					device_addr2str(RTA_DATA(attr),
						RTA_LEN(attr), 0, hw_addr,
						sizeof(hw_addr)));
			break;
		case NDA_PROBES:
			attr_fmt(attr, "Probes %d", RTA_UINT32(attr));
			break;
		case NDA_CACHEINFO:
			ci = RTA_DATA(attr);
			tprintf("\tA: Cache (");
			tprintf("confirmed(%ds)", ci->ndm_confirmed / hz);
			tprintf(", used(%ds)", ci->ndm_used / hz);
			tprintf(", updated(%ds)", ci->ndm_updated / hz);
			tprintf(", refcnt(%d))", ci->ndm_refcnt);
			tprintf(", Len %lu\n", RTA_LEN(attr));
			break;
		}
	}
}

/** 
 *  @brief              This function parses for IWEVENT events 
 *
 *  @param h            Pointer to Netlink message header
 *  @param left         Number of bytes to be read
 *  @param evt_conn     A pointer to a output buffer. It sets TRUE when it gets
 *  					the event CUS_EVT_OBSS_SCAN_PARAM, otherwise FALSE
 *  @return             Number of bytes left to be read
 */
static int
drv_iwevt_handler(struct nlmsghdr *h, int left, int *evt_conn)
{
    int len, plen, attrlen, nlmsg_len, rta_len;
    struct ifinfomsg *ifi;
    struct rtattr *attr;

    *evt_conn = FALSE;
    while (left >= sizeof(*h)) {
        len = h->nlmsg_len;
        plen = len - sizeof(*h);
        if (len > left || plen < 0) {
            /* malformed netlink message */
            break;
        }
        if (plen < sizeof(*ifi)) {
            break;
        }
        ifi = NLMSG_DATA(h);
        nlmsg_len = NLMSG_ALIGN(sizeof(struct ifinfomsg));
        attrlen = h->nlmsg_len - nlmsg_len;
        if (attrlen < 0) {
            break;
        }

        attr = (struct rtattr *) (((char *) ifi) + nlmsg_len);
        rta_len = RTA_ALIGN(sizeof(struct rtattr));
        while (RTA_OK(attr, attrlen)) {
            if (attr->rta_type == IFLA_WIRELESS) {
                struct iw_event *iwe;
                char *pos = ((char *) attr) + rta_len;
                char *end = pos + (attr->rta_len - rta_len);
                unsigned short dlen;

                while (pos + IW_EV_LCP_LEN <= end) {
                    iwe = (struct iw_event *) pos;
                    if (iwe->len <= IW_EV_LCP_LEN)
                        break;

                    switch (iwe->cmd) {
                    case SIOCGIWAP:
                        {
                            struct ether_addr *wap;
                            struct ether_addr etherzero =
                                { {0x00, 0x00, 0x00, 0x00, 0x00, 0x00} };
                            char buf[32];

                            wap = (struct ether_addr *)
                                ((struct sockaddr *) (&iwe->u.ap_addr))->
                                sa_data;

                            if (!memcmp
                                (wap, &etherzero, sizeof(struct ether_addr))) {
                                printf("---< Disconnected from AP >---\n");
                                memset(&cur_obss_scan_param, 0,
                                       sizeof(cur_obss_scan_param));
                                assoc_flag = FALSE;
                                is_ht_ap = FALSE;
                            } else {
                                memset(buf, 0, sizeof(buf));
                                sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X",
                                        wap->ether_addr_octet[0],
                                        wap->ether_addr_octet[1],
                                        wap->ether_addr_octet[2],
                                        wap->ether_addr_octet[3],
                                        wap->ether_addr_octet[4],
                                        wap->ether_addr_octet[5]);
                                printf("---< Connected to AP: %s >---\n", buf);
                                /** set TRUE, if connected */
                                assoc_flag = TRUE;
                            }
                            pos += iwe->len;
                        }
                        break;
                    case IWEVCUSTOM:
                        {
                            char *custom;
                            custom = pos + IW_EV_POINT_LEN;
                            if (IW_EV_POINT_LEN ==
                                IW_EV_LCP_LEN + sizeof(struct iw_point)) {
                                dlen = iwe->u.data.length;
                            } else {    /* WIRELESS_EXT >= 19 */
                                dlen =
                                    *((unsigned short *) (pos + IW_EV_LCP_LEN));
                            }
                            if (custom + dlen > end)
                                break;

                            printf("---< %s >---\n", custom);
                            if (!strncmp
                                (CUS_EVT_OBSS_SCAN_PARAM, custom,
//.........这里部分代码省略.........

rtnetlink::if_link& rtnetlink::if_link::operator=(message& msg)
{
	static_cast<data&>(*this) = msg;

	std::pair<const void*, size_t> pl = msg.payload();

	if (msg.type() < 16 || msg.type() > 19 || pl.second < sizeof(::ifinfomsg))
		throw "bad msg type";

	const ::ifinfomsg* ifi = reinterpret_cast<const ifinfomsg*>(pl.first);

	_type = ifi->ifi_type;
	_index = ifi->ifi_index;
	_flags = ifi->ifi_flags;

	const ::rtattr* rta = IFLA_RTA(ifi);
	size_t attrlen = IFLA_PAYLOAD(reinterpret_cast<const ::nlmsghdr*>(_msg->header()));

	for (; RTA_OK(rta, attrlen); rta = RTA_NEXT(rta, attrlen)) {
		switch (rta->rta_type) {
		case IFLA_ADDRESS:
			_address = attr<void>(RTA_DATA(rta), RTA_PAYLOAD(rta));
			break;

		case IFLA_BROADCAST:
			_bcast_addr = attr<void>(RTA_DATA(rta), RTA_PAYLOAD(rta));
			break;

		case IFLA_IFNAME:
			_name = attr<char>(RTA_DATA(rta), RTA_PAYLOAD(rta));
			break;

		case IFLA_MTU:
			ODTONE_ASSERT(sizeof(odtone::uint) == RTA_PAYLOAD(rta));
			_mtu = reinterpret_cast<odtone::uint*>(RTA_DATA(rta));
			break;

		case IFLA_LINK:
			ODTONE_ASSERT(sizeof(odtone::sint) == RTA_PAYLOAD(rta));
			_link_type = reinterpret_cast<odtone::sint*>(RTA_DATA(rta));
			break;

		case IFLA_QDISC:
			_qdisc = attr<char>(RTA_DATA(rta), RTA_PAYLOAD(rta));
			break;

		case IFLA_STATS:
			ODTONE_ASSERT(sizeof(::rtnl_link_stats) == RTA_PAYLOAD(rta));
			_stats = RTA_DATA(rta);
			break;

		case IFLA_WIRELESS:
			std::cout << "IFLA_WIRELESS(" << rta->rta_type << ", " << RTA_PAYLOAD(rta) << ")\n";
			// std::cout	<< "\tcmd: "
			// 			<< reinterpret_cast<iw_event*>(RTA_DATA(rta))->cmd
			// 			<< "  len: "
			// 			<< reinterpret_cast<iw_event*>(RTA_DATA(rta))->len
			// 			<< std::endl;

			_wifi = attr<void>(RTA_DATA(rta), RTA_PAYLOAD(rta));
			break;

		default:
			std::cout << "IFLA_UNSPEC(" << rta->rta_type << ", " << RTA_PAYLOAD(rta) << ")\n";
		}
	}

	return *this;
}