Commit 4fa0e472 authored by Ondrej Zajicek (work)'s avatar Ondrej Zajicek (work)
Browse files

BGP: Use reallocation for capability structure 

Instead of having large stack buffer for max amount of AFI/SAFI pairs.
The old code is not correct w.r.t. extendeded option length, as more
AFI/SAFI pairs may fit into the capability option.
parent 524d2538

lib/bitops.h

+2 −0
Original line number Diff line number Diff line
@@ -29,4 +29,6 @@ static inline u32 u32_hash(u32 v) { return v * 2902958171u; } 


static inline u8 u32_popcount(u32 v) { return __builtin_popcount(v); }



static inline int uint_is_pow2(uint n) { return n && !(n & (n-1)); }



#endif

proto/bgp/packets.c

+28 −16
Original line number Diff line number Diff line
@@ -185,14 +185,20 @@ bgp_find_af_caps(struct bgp_caps *caps, u32 afi) 
}



static struct bgp_af_caps *

bgp_get_af_caps(struct bgp_caps *caps, u32 afi)

bgp_get_af_caps(struct bgp_caps **pcaps, u32 afi)

{

  struct bgp_caps *caps = *pcaps;

  struct bgp_af_caps *ac;



  WALK_AF_CAPS(caps, ac)

    if (ac->afi == afi)

      return ac;



  uint n = caps->af_count;

  if (uint_is_pow2(n))

    *pcaps = caps = mb_realloc(caps, sizeof(struct bgp_caps) +

			       (2 * n) * sizeof(struct bgp_af_caps));



  ac = &caps->af_data[caps->af_count++];

  memset(ac, 0, sizeof(struct bgp_af_caps));

  ac->afi = afi;
@@ -412,13 +418,22 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf) 
}



static int

bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, int len)

bgp_read_capabilities(struct bgp_conn *conn, byte *pos, int len)

{

  struct bgp_proto *p = conn->bgp;

  struct bgp_caps *caps;

  struct bgp_af_caps *ac;

  int i, cl;

  u32 af;



  if (!conn->remote_caps)

    caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps) + sizeof(struct bgp_af_caps));

  else

  {

    caps = conn->remote_caps;

    conn->remote_caps = NULL;

  }



  caps->length += len;



  while (len > 0)
@@ -437,7 +452,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i 
	goto err;



      af = get_af4(pos+2);

      ac = bgp_get_af_caps(caps, af);

      ac = bgp_get_af_caps(&caps, af);

      ac->ready = 1;

      break;
@@ -460,7 +475,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i 
	  continue;



	af = get_af4(pos+2+i);

	ac = bgp_get_af_caps(caps, af);

	ac = bgp_get_af_caps(&caps, af);

	ac->ext_next_hop = 1;

      }

      break;
@@ -490,7 +505,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i 
      for (i = 2; i < cl; i += 4)

      {

	af = get_af3(pos+2+i);

	ac = bgp_get_af_caps(caps, af);

	ac = bgp_get_af_caps(&caps, af);

	ac->gr_able = 1;

	ac->gr_af_flags = pos[2+i+3];

      }
@@ -522,7 +537,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i 
      for (i = 0; i < cl; i += 4)

      {

	af = get_af3(pos+2+i);

	ac = bgp_get_af_caps(caps, af);

	ac = bgp_get_af_caps(&caps, af);

	ac->add_path = pos[2+i+3];

      }

      break;
@@ -551,7 +566,7 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i 
      for (i = 0; i < cl; i += 7)

      {

	af = get_af3(pos+2+i);

	ac = bgp_get_af_caps(caps, af);

	ac = bgp_get_af_caps(&caps, af);

	ac->llgr_able = 1;

	ac->llgr_flags = pos[2+i+3];

	ac->llgr_time = get_u24(pos + 2+i+4);
@@ -577,9 +592,11 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i 
    }

  }



  conn->remote_caps = caps;

  return 0;



err:

  mb_free(caps);

  bgp_error(conn, 2, 0, NULL, 0);

  return -1;

}
@@ -624,7 +641,6 @@ static int 
bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest)

{

  struct bgp_proto *p = conn->bgp;

  struct bgp_caps *caps;

  int ext = 0;



  /* Handle extended length (draft-ietf-idr-ext-opt-param-07) */
@@ -644,10 +660,6 @@ bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest) 
  if (len > rest)

    goto err;



  /* Max number of announced AFIs is limited by max option length (255) */

  caps = alloca(sizeof(struct bgp_caps) + 64 * sizeof(struct bgp_af_caps));

  memset(caps, 0, sizeof(struct bgp_caps));



  /* Length of option parameter header */

  uint hlen = ext ? 3 : 2;
@@ -666,7 +678,7 @@ bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest) 
    {

      /* BGP capabilities, RFC 5492 */

      if (p->cf->capabilities)

	if (bgp_read_capabilities(conn, caps, pos + hlen, olen) < 0)

	if (bgp_read_capabilities(conn, pos + hlen, olen) < 0)

	  return -1;

    }

    else
@@ -679,9 +691,9 @@ bgp_read_options(struct bgp_conn *conn, byte *pos, uint len, uint rest) 
    ADVANCE(pos, len, hlen + olen);

  }



  uint n = sizeof(struct bgp_caps) + caps->af_count * sizeof(struct bgp_af_caps);

  conn->remote_caps = mb_allocz(p->p.pool, n);

  memcpy(conn->remote_caps, caps, n);

  /* Prepare empty caps if no capability option was announced */

  if (!conn->remote_caps)

    conn->remote_caps = mb_allocz(p->p.pool, sizeof(struct bgp_caps));



  return 0;

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