Commit 45f01fb3 authored by Jan Moskyto Matejka's avatar Jan Moskyto Matejka
Browse files

Netlink: MPLS routes in kernel, not fully working yet. 

TODO:
- fix static to detect MPLS stack changes on reload
- fix MPLS_ENCAP parsing on route scan

Anyway, Bird is now capable to insert both MPLS routes and MPLS encap
routes into kernel.

It was (among others) needed to define platform-specific AF_MPLS to 28
as this constant has been assigned in the linux kernel.

No support for BSD now, it may be added in the future.
parent 21d358f0

lib/mpls.h

+43 −0
Original line number Diff line number Diff line
@@ -11,10 +11,53 @@ 
#define _BIRD_MPLS_H_



#define MPLS_STACK_LENGTH   8 /* Adjust this if you need deeper MPLS stack */

#define MPLS_PXLEN	    20 /* Length of the label in bits. Constant. */



/*

 *   RFC 3032 updated by RFC 5462:

 *

 *    0                   1                   2                   3

 *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Label

 *   |                Label                  | TC  |S|       TTL     | Stack

 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Entry

 *

 *                       Label:  Label Value, 20 bits

 *                       TC:     Traffic Class, 3 bits

 *                       S:      Bottom of Stack, 1 bit

 *                       TTL:    Time to Live, 8 bits

 */



typedef struct mpls_stack {

  u8 len;

  u32 label[MPLS_STACK_LENGTH];

} mpls_stack;



static inline char * const mpls_hton(mpls_stack s) {

  static char buf[MPLS_STACK_LENGTH*4];

  int i;

  for (i = 0; i < s.len; i++) {

    buf[i*4 + 0] = s.label[i] >> 12;

    buf[i*4 + 1] = s.label[i] >> 4;

    buf[i*4 + 2] = (s.label[i] << 4) | (i == s.len - 1 ? 0x1 : 0);

    buf[i*4 + 3] = 0;

  }

  return buf;

}



static inline int mpls_buflen(const char *buf) {

  // Looking for the Bottom of Stack set to 4.

  int i;

  for (i = 0; !(buf[i++*4 + 2] & 0x1); );

  return i*4;

}



static inline mpls_stack mpls_ntoh(const char *buf) {

  mpls_stack s = { .len = mpls_buflen(buf) };

  int i;

  for (i = 0; i < s.len; i++)

    s.label[i] = (buf[i*4 + 0] << 12) | (buf[i*4 + 1] << 4) | (buf[i*4 + 2] >> 4);

  return s;

}



#endif

lib/net.h

+14 −1
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#define _BIRD_NET_H_



#include "lib/ip.h"

#include "lib/mpls.h"





#define NET_IP4		1
@@ -134,7 +135,7 @@ extern const u16 net_max_text_length[]; 
  ((net_addr_roa6) { NET_ROA6, pxlen, sizeof(net_addr_roa6), prefix, max_pxlen, asn })



#define NET_ADDR_MPLS(label) \

  ((net_addr_mpls) { NET_MPLS, 0, sizeof(net_addr_mpls), label })

  ((net_addr_mpls) { NET_MPLS, MPLS_PXLEN, sizeof(net_addr_mpls), label })





static inline void net_fill_ip4(net_addr *a, ip4_addr prefix, uint pxlen)
@@ -211,6 +212,18 @@ static inline ip_addr net_prefix(const net_addr *a) 
  }

}



static inline mpls_stack net_mpls(const net_addr *a)

{

  mpls_stack ms;

  if (a->type == NET_MPLS) {

    ms.len = 1;

    ms.label[0] = ((net_addr_mpls *) a)->label;

    return ms;

  }



  bug("Can't call net_mpls on non-mpls net_addr");

}



static inline uint net4_pxlen(const net_addr *a)

{ return a->pxlen; }

sysdep/cf/linux.h

+4 −0
Original line number Diff line number Diff line
@@ -16,6 +16,10 @@ 


#define CONFIG_RESTRICTED_PRIVILEGES



#ifndef AF_MPLS

#define AF_MPLS 28

#endif



/*

Link: sysdep/linux

Link: sysdep/unix

sysdep/linux/netlink.c

+182 −15
Original line number Diff line number Diff line
@@ -26,10 +26,12 @@ 
#include "lib/socket.h"

#include "lib/string.h"

#include "lib/hash.h"

#include "lib/mpls.h"

#include "conf/conf.h"



#include <asm/types.h>

#include <linux/if.h>

#include <linux/lwtunnel.h>

#include <linux/netlink.h>

#include <linux/rtnetlink.h>
@@ -46,6 +48,25 @@ 
#define RTA_TABLE  15

#endif



#ifndef RTA_VIA

#define RTA_VIA	 18

#endif



#ifndef RTA_NEWDST

#define RTA_NEWDST  19

#endif



#ifndef RTA_ENCAP_TYPE

#define RTA_ENCAP_TYPE	21

#endif



#ifndef RTA_ENCAP

#define RTA_ENCAP  22

#endif



#ifndef AF_MPLS

#define AF_MPLS	 28

#endif



/*

 *	Synchronous Netlink interface
@@ -256,7 +277,7 @@ static struct nl_want_attrs ifa_attr_want6[BIRD_IFA_MAX] = { 
};





#define BIRD_RTA_MAX  (RTA_TABLE+1)

#define BIRD_RTA_MAX  (RTA_ENCAP+1)



static struct nl_want_attrs mpnh_attr_want4[BIRD_RTA_MAX] = {

  [RTA_GATEWAY]	  = { 1, 1, sizeof(ip4_addr) },
@@ -272,6 +293,8 @@ static struct nl_want_attrs rtm_attr_want4[BIRD_RTA_MAX] = { 
  [RTA_MULTIPATH] = { 1, 0, 0 },

  [RTA_FLOW]	  = { 1, 1, sizeof(u32) },

  [RTA_TABLE]	  = { 1, 1, sizeof(u32) },

  [RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) },

  [RTA_ENCAP]	  = { 1, 0, 0 },

};



static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = {
@@ -284,6 +307,20 @@ static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = { 
  [RTA_METRICS]	  = { 1, 0, 0 },

  [RTA_FLOW]	  = { 1, 1, sizeof(u32) },

  [RTA_TABLE]	  = { 1, 1, sizeof(u32) },

  [RTA_ENCAP_TYPE]= { 1, 1, sizeof(u16) },

  [RTA_ENCAP]	  = { 1, 0, 0 },

};



static struct nl_want_attrs rtm_attr_want_mpls[BIRD_RTA_MAX] = {

  [RTA_DST]	  = { 1, 1, sizeof(u32) },

  [RTA_IIF]	  = { 1, 1, sizeof(u32) },

  [RTA_OIF]	  = { 1, 1, sizeof(u32) },

  [RTA_PRIORITY]  = { 1, 1, sizeof(u32) },

  [RTA_METRICS]	  = { 1, 0, 0 },

  [RTA_FLOW]	  = { 1, 1, sizeof(u32) },

  [RTA_TABLE]	  = { 1, 1, sizeof(u32) },

  [RTA_VIA]	  = { 1, 0, 0 },

  [RTA_NEWDST]	  = { 1, 0, 0 },

};
@@ -333,6 +370,30 @@ static inline ip_addr rta_get_ipa(struct rtattr *a) 
    return ipa_from_ip6(rta_get_ip6(a));

}



static inline ip_addr rta_get_via(struct rtattr *a)

{

  struct rtvia *v = RTA_DATA(a);

  switch(v->rtvia_family) {

    case AF_INET:  return ipa_from_ip4(ip4_ntoh(*(ip4_addr *) v->rtvia_addr));

    case AF_INET6: return ipa_from_ip6(ip6_ntoh(*(ip6_addr *) v->rtvia_addr));

  }

  return IPA_NONE;

}



static inline mpls_stack rta_get_mpls(struct rtattr *a)

{

  mpls_stack ms = { .len = RTA_PAYLOAD(a) / 4 };

  for (int i = 0; i < ms.len; i++) {

    ms.label[i] = (((u8 *)RTA_DATA(a))[i*4 + 0] << 12)

		| (((u8 *)RTA_DATA(a))[i*4 + 1] <<  4)

		| (((u8 *)RTA_DATA(a))[i*4 + 2] >>  4);



    if (!!(((u8 *)RTA_DATA(a))[i*4 + 2] & 1) != (i+1 == ms.len))

      log(L_WARN "KRT: Received a route with mismatched MPLS BoS bit, ignoring");

  }

  return ms;

}



struct rtattr *

nl_add_attr(struct nlmsghdr *h, uint bufsize, uint code, const void *data, uint dlen)

{
@@ -353,6 +414,24 @@ nl_add_attr(struct nlmsghdr *h, uint bufsize, uint code, const void *data, uint 
  return a;

}



static inline struct rtattr *

nl_open_attr(struct nlmsghdr *h, uint bufsize, uint code)

{

  return nl_add_attr(h, bufsize, code, NULL, 0);

}



static inline void

nl_close_attr(struct nlmsghdr *h, struct rtattr *a)

{

  a->rta_len = (void *)h + h->nlmsg_len - (void *)a;

}



static inline void

nl_add_attr_u16(struct nlmsghdr *h, uint bufsize, int code, u16 data)

{

  nl_add_attr(h, bufsize, code, &data, 2);

}



static inline void

nl_add_attr_u32(struct nlmsghdr *h, uint bufsize, int code, u32 data)

{
@@ -382,16 +461,46 @@ nl_add_attr_ipa(struct nlmsghdr *h, uint bufsize, int code, ip_addr ipa) 
    nl_add_attr_ip6(h, bufsize, code, ipa_to_ip6(ipa));

}



static inline struct rtattr *

nl_open_attr(struct nlmsghdr *h, uint bufsize, uint code)

static inline void

nl_add_attr_mpls(struct nlmsghdr *h, uint bufsize, int code, mpls_stack ms)

{

  return nl_add_attr(h, bufsize, code, NULL, 0);

  const char *buf = mpls_hton(ms);

  nl_add_attr(h, bufsize, code, buf, mpls_buflen(buf));

}



static inline void

nl_close_attr(struct nlmsghdr *h, struct rtattr *a)

nl_add_attr_mpls_encap(struct nlmsghdr *h, uint bufsize, mpls_stack ms)

{

  a->rta_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)a;

  struct rtattr *nest = nl_open_attr(h, bufsize, RTA_ENCAP);

  nl_add_attr_mpls(h, bufsize, RTA_DST, ms);

  nl_close_attr(h, nest);



  nl_add_attr_u16(h, bufsize, RTA_ENCAP_TYPE, LWTUNNEL_ENCAP_MPLS);

}



static inline void

nl_add_attr_via(struct nlmsghdr *h, uint bufsize, ip_addr ipa)

{

  struct rtattr *nest = nl_open_attr(h, bufsize, RTA_VIA);

  struct rtvia *via = RTA_DATA(nest);



  h->nlmsg_len += sizeof(*via);



  if (ipa_is_ip4(ipa)) {

    ip4_addr ip4 = ipa_to_ip4(ipa);

    ip4 = ip4_hton(ip4);

    via->rtvia_family = AF_INET;

    memcpy(via->rtvia_addr, &ip4, sizeof(ip4));

    h->nlmsg_len += sizeof(ip4);

  } else {

    ip6_addr ip6 = ipa_to_ip6(ipa);

    ip6 = ip6_hton(ip6);

    via->rtvia_family = AF_INET6;

    memcpy(via->rtvia_addr, &ip6, sizeof(ip6));

    h->nlmsg_len += sizeof(ip6);

  }



  nl_close_attr(h, nest);

}



static inline struct rtnexthop *
@@ -411,7 +520,7 @@ nl_open_nexthop(struct nlmsghdr *h, uint bufsize) 
static inline void

nl_close_nexthop(struct nlmsghdr *h, struct rtnexthop *nh)

{

  nh->rtnh_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)nh;

  nh->rtnh_len = (void *)h + h->nlmsg_len - (void *)nh;

}



static void
@@ -909,6 +1018,15 @@ nh_bufsize(struct mpnh *nh) 
  return rv;

}



static inline mpls_stack

mpls_from_ea(struct adata *ad) {

  mpls_stack s = { .len = ad->length/sizeof(u32) };

  int i;

  for (i = 0; i < s.len; i++)

    s.label[i] = ((u32 *) ad->data)[i];

  return s;

}



static int

nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new)

{
@@ -933,6 +1051,9 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) 
  r.r.rtm_dst_len = net_pxlen(net->n.addr);

  r.r.rtm_protocol = RTPROT_BIRD;

  r.r.rtm_scope = RT_SCOPE_UNIVERSE;

  if (p->af == AF_MPLS)

    nl_add_attr_mpls(&r.h, sizeof(r), RTA_DST, net_mpls(net->n.addr));

  else

    nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net_prefix(net->n.addr));



  if (krt_table_id(p) < 256)
@@ -944,6 +1065,11 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) 
  if (!new)

    return nl_exchange(&r.h);



  if (ea = ea_find(eattrs, EA_GEN_MPLS_STACK))

    if (p->af == AF_MPLS)

      nl_add_attr_mpls(&r.h, sizeof(r), RTA_NEWDST, mpls_from_ea(ea->u.ptr));

    else

      nl_add_attr_mpls_encap(&r.h, sizeof(r), mpls_from_ea(ea->u.ptr));



  if (ea = ea_find(eattrs, EA_KRT_METRIC))

    nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, ea->u.data);
@@ -977,6 +1103,9 @@ nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new) 
    case RTD_ROUTER:

      r.r.rtm_type = RTN_UNICAST;

      nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);

      if (p->af == AF_MPLS)

	nl_add_attr_via(&r.h, sizeof(r), a->gw);

      else

	nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw);

      break;

    case RTD_DEVICE:
@@ -1068,6 +1197,16 @@ nl_parse_route(struct nlmsghdr *h, int scan) 
	net_fill_ip6(&dst, IP6_NONE, 0);

      break;



    case AF_MPLS:

      if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want_mpls, a, sizeof(a)))

	return;



      if (a[RTA_DST])

	net_fill_mpls(&dst, rta_get_mpls(a[RTA_DST]).label[0]);

      else

	return; /* No support for MPLS routes without RTA_DST */

      break;



    default:

      return;

    }
@@ -1096,7 +1235,7 @@ nl_parse_route(struct nlmsghdr *h, int scan) 
    SKIP("RTM_DELROUTE in scan\n");



  int c = net_classify(&dst);

  if ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK))

  if (i->rtm_family != AF_MPLS && ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK)))

    SKIP("strange class/scope\n");



  // ignore rtm_scope, it is not a real scope
@@ -1160,9 +1299,12 @@ nl_parse_route(struct nlmsghdr *h, int scan) 
	  return;

	}



      if (a[RTA_GATEWAY])

      if ((i->rtm_family != AF_MPLS) && a[RTA_GATEWAY] || (i->rtm_family == AF_MPLS) && a[RTA_VIA])

	{

	  ra.dest = RTD_ROUTER;

	  if (i->rtm_family == AF_MPLS)

	    ra.gw = rta_get_via(a[RTA_VIA]);

	  else

	    ra.gw = rta_get_ipa(a[RTA_GATEWAY]);



	  /* Silently skip strange 6to4 routes */
@@ -1210,6 +1352,24 @@ nl_parse_route(struct nlmsghdr *h, int scan) 
  if (a[RTA_PRIORITY])

    e->u.krt.metric = rta_get_u32(a[RTA_PRIORITY]);



  if ((i->rtm_family == AF_MPLS) && a[RTA_NEWDST])

    {

      mpls_stack ms = rta_get_mpls(a[RTA_NEWDST]);



      ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr));

      ea->next = ra.eattrs;

      ra.eattrs = ea;

      ea->flags = EALF_SORTED;

      ea->count = 1;

      ea->attrs[0].id = EA_KRT_PREFSRC;

      ea->attrs[0].flags = 0;

      ea->attrs[0].type = EAF_TYPE_INT_SET;

      ea->attrs[0].u.ptr = alloca(sizeof(struct adata) + sizeof(u32)*ms.len);

      ea->attrs[0].u.ptr->length = sizeof(u32)*ms.len;

      for (int j = 0; j < ms.len; j++)

	((u32 *)ea->attrs[0].u.ptr->data)[j] = ms.label[j];

    }



  if (a[RTA_PREFSRC])

    {

      ip_addr ps = rta_get_ipa(a[RTA_PREFSRC]);
@@ -1295,6 +1455,13 @@ krt_do_scan(struct krt_proto *p UNUSED) /* CONFIG_ALL_TABLES_AT_ONCE => p is NUL 
      nl_parse_route(h, 1);

    else

      log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);



  nl_request_dump(AF_MPLS, RTM_GETROUTE);

  while (h = nl_get_scan())

    if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)

      nl_parse_route(h, 1);

    else

      log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);

}



/*

sysdep/unix/krt.c

+3 −2
Original line number Diff line number Diff line
@@ -1144,7 +1144,8 @@ krt_start(struct proto *P) 
  {

  case NET_IP4:	p->af = AF_INET; break;

  case NET_IP6:	p->af = AF_INET6; break;

  default:	ASSERT(0);

  case NET_MPLS: p->af = AF_MPLS; break;

  default: log(L_ERR "KRT: Tried to start with strange net type: %d", p->p.net_type); return PS_START; break;

  }



  add_tail(&krt_proto_list, &p->krt_node);
@@ -1255,7 +1256,7 @@ struct protocol proto_unix_kernel = { 
  .template =		"kernel%d",

  .attr_class =		EAP_KRT,

  .preference =		DEF_PREF_INHERITED,

  .channel_mask =	NB_IP,

  .channel_mask =	NB_IP | NB_MPLS,

  .proto_size =		sizeof(struct krt_proto),

  .config_size =	sizeof(struct krt_config),

  .preconfig =		krt_preconfig,

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