Route Origin Authorization basics.

 - ROA tables, which are used as a basic part for RPKI.
 - Commands for examining and modifying ROA tables.
 - Filter operators based on ROA tables consistent with RFC 6483.

1 files changed, 440 insertions, 0 deletions

diff --git a/nest/rt-roa.c b/nest/rt-roa.c
new file mode 100644
index 00000000..f94842c4
--- /dev/null
+++ b/nest/rt-roa.c
@@ -0,0 +1,440 @@
+/*
+ *	BIRD -- Route Origin Authorization
+ *
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#undef LOCAL_DEBUG
+
+#include "nest/bird.h"
+#include "nest/route.h"
+#include "nest/cli.h"
+#include "lib/lists.h"
+#include "lib/resource.h"
+#include "lib/event.h"
+#include "lib/string.h"
+#include "conf/conf.h"
+
+
+pool *roa_pool;
+static slab *roa_slab;			/* Slab of struct roa_item */
+static list roa_table_list;		/* List of struct roa_table */
+struct roa_table *roa_table_default;	/* The first ROA table in the config */
+
+static inline int
+src_match(struct roa_item *it, byte src)
+{ return !src || it->src == src; }
+
+/**
+ * roa_add_item - add a ROA entry
+ * @t: ROA table
+ * @prefix: prefix of the ROA entry
+ * @pxlen: prefix length of the ROA entry
+ * @maxlen: max length field of the ROA entry
+ * @asn: AS number field of the ROA entry
+ * @src: source of the ROA entry (ROA_SRC_*)
+ *
+ * The function adds a new ROA entry to the ROA table. If the same ROA
+ * is already in the table, nothing is added. @src field is used to
+ * distinguish different sources of ROAs.
+ */
+void
+roa_add_item(struct roa_table *t, ip_addr prefix, byte pxlen, byte maxlen, u32 asn, byte src)
+{
+  struct roa_node *n = fib_get(&t->fib, &prefix, pxlen);
+
+  // if ((n->items == NULL) && (n->n.x0 != ROA_INVALID))
+  // t->cached_items--;
+
+  struct roa_item *it;
+  for (it = n->items; it; it = it->next)
+    if ((it->maxlen == maxlen) && (it->asn == asn) && src_match(it, src))
+      return;
+
+  it = sl_alloc(roa_slab);
+  it->asn = asn;
+  it->maxlen = maxlen;
+  it->src = src;
+  it->next = n->items;
+  n->items = it;
+}
+
+/**
+ * roa_delete_item - delete a ROA entry
+ * @t: ROA table
+ * @prefix: prefix of the ROA entry
+ * @pxlen: prefix length of the ROA entry
+ * @maxlen: max length field of the ROA entry
+ * @asn: AS number field of the ROA entry
+ * @src: source of the ROA entry (ROA_SRC_*)
+ *
+ * The function removes a specified ROA entry from the ROA table and
+ * frees it. If @src field is not ROA_SRC_ANY, only entries from
+ * that source are considered.
+ */
+void
+roa_delete_item(struct roa_table *t, ip_addr prefix, byte pxlen, byte maxlen, u32 asn, byte src)
+{
+  struct roa_node *n = fib_find(&t->fib, &prefix, pxlen);
+
+  if (!n)
+    return;
+
+  struct roa_item *it, **itp;
+  for (itp = &n->items; it = *itp; itp = &it->next)
+    if ((it->maxlen == maxlen) && (it->asn == asn) && src_match(it, src))
+      break;
+
+  if (!it)
+    return;
+
+  *itp = it->next;
+  sl_free(roa_slab, it);
+
+  // if ((n->items == NULL) && (n->n.x0 != ROA_INVALID))
+  // t->cached_items++;
+}
+
+
+/**
+ * roa_flush - flush a ROA table
+ * @t: ROA table
+ * @src: source of ROA entries (ROA_SRC_*)
+ *
+ * The function removes and frees ROA entries from the ROA table. If
+ * @src is ROA_SRC_ANY, all entries in the table are removed,
+ * otherwise only all entries from that source are removed.
+ */
+void
+roa_flush(struct roa_table *t, byte src)
+{
+  struct roa_item *it, **itp;
+  struct roa_node *n;
+
+  FIB_WALK(&t->fib, fn)
+    {
+      n = (struct roa_node *) fn;
+
+      itp = &n->items;
+      while (it = *itp)
+	if (src_match(it, src))
+	  {
+	    *itp = it->next;
+	    sl_free(roa_slab, it);
+	  }
+	else
+	  itp = &it->next;
+    }
+  FIB_WALK_END;
+
+  // TODO add cleanup of roa_nodes
+}
+
+
+
+/*
+byte
+roa_check(struct roa_table *t, ip_addr prefix, byte pxlen, u32 asn)
+{
+  struct roa_node *n = fib_find(&t->fib, &prefix, pxlen);
+
+  if (n && n->n.x0 == ROA_UNKNOWN)
+    return ROA_UNKNOWN;
+
+  if (n && n->n.x0 == ROA_VALID && asn == n->cached_asn)
+    return ROA_VALID;
+
+  byte rv = roa_match(t, n, prefix, pxlen, asn);
+
+  if (rv != ROA_INVALID)
+    {
+      if (!n)
+	{
+	  if (t->cached_items >= t->cached_items_max)
+	  n = fib_get(&t->fib, &prefix, pxlen);
+	  t->cached_items++;
+	}
+
+      n->cached_asn = asn;
+      n->n.x0 = rv;
+    }
+
+  return rv;
+}
+*/
+
+/**
+ * roa_check - check validity of route origination in a ROA table 
+ * @t: ROA table
+ * @prefix: network prefix to check
+ * @pxlen: length of network prefix
+ * @asn: AS number of network prefix
+ *
+ * Implements RFC 6483 route validation for the given network
+ * prefix. The procedure is to find all candidate ROAs - ROAs whose
+ * prefixes cover the give network prefix. If there is no candidate
+ * ROA, return ROA_UNKNOWN. If there is a candidate ROA with matching
+ * ASN and maxlen field greater than or equal to the given prefix
+ * length, return ROA_VALID. Otherwise return ROA_INVALID. If caller
+ * cannot determine origin AS, 0 could be used (in that case ROA_VALID
+ * cannot happen).
+ */
+byte
+roa_check(struct roa_table *t, ip_addr prefix, byte pxlen, u32 asn)
+{
+  struct roa_node *n;
+  ip_addr px;
+  byte anything = 0;
+
+  int len;
+  for (len = pxlen; len >= 0; len--)
+    {
+      px = ipa_and(prefix, ipa_mkmask(len));
+      n = fib_find(&t->fib, &px, len);
+
+      if (!n)
+	continue;
+
+      struct roa_item *it;
+      for (it = n->items; it; it = it->next)
+	{
+	  anything = 1;
+	  if ((it->maxlen >= pxlen) && (it->asn == asn) && asn)
+	    return ROA_VALID;
+	}
+    }
+
+  return anything ? ROA_INVALID : ROA_UNKNOWN;
+}
+
+static void
+roa_node_init(struct fib_node *fn)
+{
+  struct roa_node *n = (struct roa_node *) fn;
+  n->items = NULL;
+}
+
+static inline void
+roa_populate(struct roa_table *t)
+{
+  struct roa_item_config *ric;
+  for (ric = t->cf->roa_items; ric; ric = ric->next)
+    roa_add_item(t, ric->prefix, ric->pxlen, ric->maxlen, ric->asn, ROA_SRC_CONFIG);
+}
+
+static void
+roa_new_table(struct roa_table_config *cf)
+{
+  struct roa_table *t;
+
+  t = mb_allocz(roa_pool, sizeof(struct roa_table));
+  fib_init(&t->fib, roa_pool, sizeof(struct roa_node), 0, roa_node_init);
+  t->name = cf->name;
+  t->cf = cf;
+
+  cf->table = t;
+  add_tail(&roa_table_list, &t->n);
+
+  roa_populate(t);
+}
+
+struct roa_table_config *
+roa_new_table_config(struct symbol *s)
+{
+  struct roa_table_config *rtc = cfg_allocz(sizeof(struct roa_table_config));
+
+  cf_define_symbol(s, SYM_ROA, rtc);
+  rtc->name = s->name;
+  add_tail(&new_config->roa_tables, &rtc->n);
+  return rtc;
+}
+
+/**
+ * roa_add_item_config - add a static ROA entry to a ROA table configuration
+ *
+ * Arguments are self-explanatory. The first is the ROA table config, rest
+ * are specifying the ROA entry.
+ */
+void
+roa_add_item_config(struct roa_table_config *rtc, ip_addr prefix, byte pxlen, byte maxlen, u32 asn)
+{
+  struct roa_item_config *ric = cfg_allocz(sizeof(struct roa_item_config));
+
+  ric->prefix = prefix;
+  ric->pxlen = pxlen;
+  ric->maxlen = maxlen;
+  ric->asn = asn;
+  ric->next = rtc->roa_items;
+  rtc->roa_items = ric;
+}
+
+/**
+ * roa_init - initialize ROA tables
+ *
+ * This function is called during BIRD startup. It initializes
+ * the ROA table module.
+ */
+void
+roa_init(void)
+{
+  roa_pool = rp_new(&root_pool, "ROA tables");
+  roa_slab = sl_new(roa_pool, sizeof(struct roa_item));
+  init_list(&roa_table_list);
+}
+
+void
+roa_preconfig(struct config *c)
+{
+  init_list(&c->roa_tables);
+}
+
+
+/**
+ * roa_commit - commit new ROA table configuration
+ * @new: new configuration
+ * @old: original configuration or %NULL if it's boot time config
+ *
+ * Scan differences between @old and @new configuration and modify the
+ * ROA tables according to these changes. If @new defines a previously
+ * unknown table, create it, if it omits a table existing in @old,
+ * delete it (there are no references, only indirect through struct
+ * roa_table_config). If it exists in both configurations, update the
+ * configured ROA entries.
+ */
+void
+roa_commit(struct config *new, struct config *old)
+{
+  struct roa_table_config *cf;
+  struct roa_table *t;
+
+  if (old)
+    WALK_LIST(t, roa_table_list)
+      {
+	struct symbol *sym = cf_find_symbol(t->name);
+	if (sym && sym->class == SYM_ROA)
+	  {
+	    /* Found old table in new config */
+	    cf = sym->def;
+	    cf->table = t;
+	    t->name = cf->name;
+	    t->cf = cf;
+
+	    /* Reconfigure it */
+	    roa_flush(t, ROA_SRC_CONFIG);
+	    roa_populate(t);
+	  }
+	else
+	  {
+	    t->cf->table = NULL;
+
+	    /* Free it now */
+	    roa_flush(t, ROA_SRC_ANY);
+	    rem_node(&t->n);
+	    fib_free(&t->fib);
+	    mb_free(t);
+	  }
+      }
+
+  /* Add new tables */
+  WALK_LIST(cf, new->roa_tables)
+    if (! cf->table)
+      roa_new_table(cf);
+
+  roa_table_default = EMPTY_LIST(new->roa_tables) ? NULL :
+    ((struct roa_table_config *) HEAD(new->roa_tables))->table;
+}
+
+
+
+static void
+roa_show_node(struct cli *c, struct roa_node *rn, int len, u32 asn)
+{
+  struct roa_item *ri;
+
+  for (ri = rn->items; ri; ri = ri->next)
+    if ((ri->maxlen >= len) && (!asn || (ri->asn == asn)))
+      cli_printf(c, -1111, "%I/%d max %d as %u", rn->n.prefix, rn->n.pxlen, ri->maxlen, ri->asn);
+}
+
+static void
+roa_show_cont(struct cli *c)
+{
+  struct roa_show_data *d = c->rover;
+  struct fib *fib = &d->table->fib;
+  struct fib_iterator *it = &d->fit;
+  struct roa_node *rn;
+  unsigned max = 32;
+
+  FIB_ITERATE_START(fib, it, f)
+    {
+      rn = (struct roa_node *) f;
+
+      if (!max--)
+	{
+	  FIB_ITERATE_PUT(it, f);
+	  return;
+	}
+
+      if ((d->mode == ROA_SHOW_ALL) ||
+	  net_in_net(rn->n.prefix, rn->n.pxlen, d->prefix, d->pxlen))
+	roa_show_node(c, rn, 0, d->asn);
+    }
+  FIB_ITERATE_END(f);
+
+  cli_printf(c, 0, "");
+  c->cont = c->cleanup = NULL;
+}
+
+static void
+roa_show_cleanup(struct cli *c)
+{
+  struct roa_show_data *d = c->rover;
+
+  /* Unlink the iterator */
+  fit_get(&d->table->fib, &d->fit);
+}
+
+void
+roa_show(struct roa_show_data *d)
+{
+  struct roa_node *rn;
+  ip_addr px;
+  int len;
+
+  switch (d->mode)
+    {
+    case ROA_SHOW_ALL:
+    case ROA_SHOW_IN:
+      FIB_ITERATE_INIT(&d->fit, &d->table->fib);
+      this_cli->cont = roa_show_cont;
+      this_cli->cleanup = roa_show_cleanup;
+      this_cli->rover = d;
+      break;
+
+    case ROA_SHOW_PX:
+      rn = fib_find(&d->table->fib, &d->prefix, d->pxlen);
+      if (rn)
+	{
+	  roa_show_node(this_cli, rn, 0, d->asn);
+	  cli_msg(0, "");
+	}
+      else
+	cli_msg(-8001, "Network not in table");
+      break;
+
+    case ROA_SHOW_FOR:
+      for (len = d->pxlen; len >= 0; len--)
+	{
+	  px = ipa_and(d->prefix, ipa_mkmask(len));
+	  rn = fib_find(&d->table->fib, &px, len);
+
+	  if (!rn)
+	    continue;
+
+	  roa_show_node(this_cli, rn, 0, d->asn);
+	}
+      cli_msg(0, "");
+      break;
+    }
+}