kernel_socket.c

zebra测试源代码用于 SOCKET 通信

	  memcpy ((caddr_t)(X), pnt, len); \
	pnt += len; \
      }

  /* Be sure structure is cleared */
  memset (dest, 0, sizeof (union sockunion));
  memset (gate, 0, sizeof (union sockunion));
  memset (mask, 0, sizeof (union sockunion));

  /* We fetch each socket variable into sockunion. */
  RTMADDRGET (dest, RTA_DST);
  RTMADDRGET (gate, RTA_GATEWAY);
  RTMMASKGET (mask, RTA_NETMASK);
  RTMADDRGET (NULL, RTA_GENMASK);
  RTMADDRGET (NULL, RTA_IFP);
  RTMADDRGET (NULL, RTA_IFA);
  RTMADDRGET (NULL, RTA_AUTHOR);
  RTMADDRGET (NULL, RTA_BRD);

  /* If there is netmask information set it's family same as
     destination family*/
  if (rtm->rtm_addrs & RTA_NETMASK)
    mask->sa.sa_family = dest->sa.sa_family;

  /* Assert read up to the end of pointer. */
  if (pnt != end) 
      zlog (NULL, LOG_WARNING, "rtm_read() does't read all socket data.");

  return rtm->rtm_flags;
}

void
rtm_read (struct rt_msghdr *rtm)
{
  int flags;
  u_char zebra_flags;
  union sockunion dest, mask, gate;

  zebra_flags = 0;

  /* Discard self send message. */
  if (rtm->rtm_type != RTM_GET 
      && (rtm->rtm_pid == pid || rtm->rtm_pid == old_pid))
    return;

  /* Read destination and netmask and gateway from rtm message
     structure. */
  flags = rtm_read_mesg (rtm, &dest, &mask, &gate);

#ifdef RTF_CLONED	/*bsdi, netbsd 1.6*/
  if (flags & RTF_CLONED)
    return;
#endif
#ifdef RTF_WASCLONED	/*freebsd*/
  if (flags & RTF_WASCLONED)
    return;
#endif

  if ((rtm->rtm_type == RTM_ADD) && ! (flags & RTF_UP))
    return;

  /* This is connected route. */
  if (! (flags & RTF_GATEWAY))
      return;

  if (flags & RTF_PROTO1)
    SET_FLAG (zebra_flags, ZEBRA_FLAG_SELFROUTE);

  /* This is persistent route. */
  if (flags & RTF_STATIC)
    SET_FLAG (zebra_flags, ZEBRA_FLAG_STATIC);

  if (dest.sa.sa_family == AF_INET)
    {
      struct prefix_ipv4 p;

      p.family = AF_INET;
      p.prefix = dest.sin.sin_addr;
      if (flags & RTF_HOST)
	p.prefixlen = IPV4_MAX_PREFIXLEN;
      else
	p.prefixlen = ip_masklen (mask.sin.sin_addr);

      if (rtm->rtm_type == RTM_GET || rtm->rtm_type == RTM_ADD)
	rib_add_ipv4 (ZEBRA_ROUTE_KERNEL, zebra_flags, 
		      &p, &gate.sin.sin_addr, 0, 0, 0, 0);
      else
	rib_delete_ipv4 (ZEBRA_ROUTE_KERNEL, zebra_flags, 
		      &p, &gate.sin.sin_addr, 0, 0);
    }
#ifdef HAVE_IPV6
  if (dest.sa.sa_family == AF_INET6)
    {
      struct prefix_ipv6 p;
      unsigned int ifindex = 0;

      p.family = AF_INET6;
      p.prefix = dest.sin6.sin6_addr;
      if (flags & RTF_HOST)
	p.prefixlen = IPV6_MAX_PREFIXLEN;
      else
	p.prefixlen = ip6_masklen (mask.sin6.sin6_addr);

#ifdef KAME
      if (IN6_IS_ADDR_LINKLOCAL (&gate.sin6.sin6_addr))
	{
	  ifindex = IN6_LINKLOCAL_IFINDEX (gate.sin6.sin6_addr);
	  SET_IN6_LINKLOCAL_IFINDEX (gate.sin6.sin6_addr, 0);
	}
#endif /* KAME */

      if (rtm->rtm_type == RTM_GET || rtm->rtm_type == RTM_ADD)
	rib_add_ipv6 (ZEBRA_ROUTE_KERNEL, zebra_flags,
		      &p, &gate.sin6.sin6_addr, ifindex, 0);
      else
	rib_delete_ipv6 (ZEBRA_ROUTE_KERNEL, zebra_flags,
			 &p, &gate.sin6.sin6_addr, ifindex, 0);
    }
#endif /* HAVE_IPV6 */
}

/* Interface function for the kernel routing table updates.  Support
   for RTM_CHANGE will be needed. */
int
rtm_write (int message,
	   union sockunion *dest,
	   union sockunion *mask,
	   union sockunion *gate,
	   unsigned int index,
	   int zebra_flags,
	   int metric)
{
  int ret;
  caddr_t pnt;
  struct interface *ifp;
  struct sockaddr_in tmp_gate;
#ifdef HAVE_IPV6
  struct sockaddr_in6 tmp_gate6;
#endif /* HAVE_IPV6 */

  /* Sequencial number of routing message. */
  static int msg_seq = 0;

  /* Struct of rt_msghdr and buffer for storing socket's data. */
  struct 
  {
    struct rt_msghdr rtm;
    char buf[512];
  } msg;
  
  memset (&tmp_gate, 0, sizeof (struct sockaddr_in));
  tmp_gate.sin_family = AF_INET;
#ifdef HAVE_SIN_LEN
  tmp_gate.sin_len = sizeof (struct sockaddr_in);
#endif /* HAVE_SIN_LEN */

#ifdef HAVE_IPV6
  memset (&tmp_gate6, 0, sizeof (struct sockaddr_in6));
  tmp_gate6.sin6_family = AF_INET6;
#ifdef SIN6_LEN
  tmp_gate6.sin6_len = sizeof (struct sockaddr_in6);
#endif /* SIN6_LEN */
#endif /* HAVE_IPV6 */

  if (routing_sock < 0)
    return ZEBRA_ERR_EPERM;

  /* Clear and set rt_msghdr values */
  memset (&msg, 0, sizeof (struct rt_msghdr));
  msg.rtm.rtm_version = RTM_VERSION;
  msg.rtm.rtm_type = message;
  msg.rtm.rtm_seq = msg_seq++;
  msg.rtm.rtm_addrs = RTA_DST;
  msg.rtm.rtm_addrs |= RTA_GATEWAY;
  msg.rtm.rtm_flags = RTF_UP;
  msg.rtm.rtm_index = index;

  if (metric != 0)
    {
      msg.rtm.rtm_rmx.rmx_hopcount = metric;
      msg.rtm.rtm_inits |= RTV_HOPCOUNT;
    }

  ifp = if_lookup_by_index (index);

  if (gate && message == RTM_ADD)
    msg.rtm.rtm_flags |= RTF_GATEWAY;

  if (! gate && message == RTM_ADD && ifp &&
      (ifp->flags & IFF_POINTOPOINT) == 0)
    msg.rtm.rtm_flags |= RTF_CLONING;

  /* If no protocol specific gateway is specified, use link
     address for gateway. */
  if (! gate)
    {
      if (!ifp)
        {
          zlog_warn ("no gateway found for interface index %d", index);
          return -1;
        }
      gate = (union sockunion *) & ifp->sdl;
    }

  if (mask)
    msg.rtm.rtm_addrs |= RTA_NETMASK;
  else if (message == RTM_ADD) 
    msg.rtm.rtm_flags |= RTF_HOST;

  /* Tagging route with flags */
  msg.rtm.rtm_flags |= (RTF_PROTO1);

  /* Additional flags. */
  if (zebra_flags & ZEBRA_FLAG_BLACKHOLE)
    msg.rtm.rtm_flags |= RTF_BLACKHOLE;

#ifdef HAVE_SIN_LEN
#define SOCKADDRSET(X,R) \
  if (msg.rtm.rtm_addrs & (R)) \
    { \
      int len = ROUNDUP ((X)->sa.sa_len); \
      memcpy (pnt, (caddr_t)(X), len); \
      pnt += len; \
    }
#else 
#define SOCKADDRSET(X,R) \
  if (msg.rtm.rtm_addrs & (R)) \
    { \
      int len = ROUNDUP (sizeof((X)->sa)); \
      memcpy (pnt, (caddr_t)(X), len); \
      pnt += len; \
    }
#endif /* HAVE_SIN_LEN */

  pnt = (caddr_t) msg.buf;

  /* Write each socket data into rtm message buffer */
  SOCKADDRSET (dest, RTA_DST);
  SOCKADDRSET (gate, RTA_GATEWAY);
  SOCKADDRSET (mask, RTA_NETMASK);

  msg.rtm.rtm_msglen = pnt - (caddr_t) &msg;

  ret = write (routing_sock, &msg, msg.rtm.rtm_msglen);

  if (ret != msg.rtm.rtm_msglen) 
    {
      if (errno == EEXIST) 
	return ZEBRA_ERR_RTEXIST;
      if (errno == ENETUNREACH)
	return ZEBRA_ERR_RTUNREACH;
      
      zlog_warn ("write : %s (%d)", strerror (errno), errno);
      return -1;
    }
  return 0;
}


#include "thread.h"
#include "zebra/zserv.h"

extern struct thread_master *master;

/* For debug purpose. */
void
rtmsg_debug (struct rt_msghdr *rtm)
{
  char *type = "Unknown";
  struct message *mes;

  for (mes = rtm_type_str; mes->str; mes++)
    if (mes->key == rtm->rtm_type)
      {
	type = mes->str;
	break;
      }

  zlog_info ("Kernel: Len: %d Type: %s", rtm->rtm_msglen, type);
  rtm_flag_dump (rtm->rtm_flags);
  zlog_info ("Kernel: message seq %d", rtm->rtm_seq);
  zlog_info ("Kernel: pid %d", rtm->rtm_pid);
}

/* This is pretty gross, better suggestions welcome -- mhandler */
#ifndef RTAX_MAX
#ifdef RTA_NUMBITS
#define RTAX_MAX	RTA_NUMBITS
#else
#define RTAX_MAX	8
#endif /* RTA_NUMBITS */
#endif /* RTAX_MAX */

/* Kernel routing table and interface updates via routing socket. */
int
kernel_read (struct thread *thread)
{
  int sock;
  int nbytes;
  struct rt_msghdr *rtm;

  union 
  {
    /* Routing information. */
    struct 
    {
      struct rt_msghdr rtm;
      struct sockaddr addr[RTAX_MAX];
    } r;

    /* Interface information. */
    struct
    {
      struct if_msghdr ifm;
      struct sockaddr addr[RTAX_MAX];
    } im;

    /* Interface address information. */
    struct
    {
      struct ifa_msghdr ifa;
      struct sockaddr addr[RTAX_MAX];
    } ia;

#ifdef RTM_IFANNOUNCE
    /* Interface arrival/departure */
    struct
    {
      struct if_announcemsghdr ifan;
      struct sockaddr addr[RTAX_MAX];
    } ian;
#endif /* RTM_IFANNOUNCE */

  } buf;

  /* Fetch routing socket. */
  sock = THREAD_FD (thread);

  nbytes= read (sock, &buf, sizeof buf);

  if (nbytes <= 0)
    {
      if (nbytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN)
	zlog_warn ("routing socket error: %s", strerror (errno));
      return 0;
    }

  thread_add_read (master, kernel_read, NULL, sock);

#ifdef DEBUG
  rtmsg_debug (&buf.r.rtm);
#endif /* DEBUG */

  rtm = &buf.r.rtm;

  switch (rtm->rtm_type)
    {
    case RTM_ADD:
    case RTM_DELETE:
      rtm_read (rtm);
      break;
    case RTM_IFINFO:
      ifm_read (&buf.im.ifm);
      break;
    case RTM_NEWADDR:
    case RTM_DELADDR:
      ifam_read (&buf.ia.ifa);
      break;
#ifdef RTM_IFANNOUNCE
    case RTM_IFANNOUNCE:
      ifan_read (&buf.ian.ifan);
      break;
#endif /* RTM_IFANNOUNCE */
    default:
      break;
    }
  return 0;
}

/* Make routing socket. */
void
routing_socket ()
{
  routing_sock = socket (AF_ROUTE, SOCK_RAW, 0);

  if (routing_sock < 0) 
    {
      zlog_warn ("Can't init kernel routing socket");
      return;
    }

  if (fcntl (routing_sock, F_SETFL, O_NONBLOCK) < 0) 
    zlog_warn ("Can't set O_NONBLOCK to routing socket");

  /* kernel_read needs rewrite. */
  thread_add_read (master, kernel_read, NULL, routing_sock);
}

/* Exported interface function.  This function simply calls
   routing_socket (). */
void
kernel_init ()
{
  routing_socket ();
}