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Diffstat (limited to 'lib/srcdest_table.c')
| -rw-r--r-- | lib/srcdest_table.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/lib/srcdest_table.c b/lib/srcdest_table.c new file mode 100644 index 0000000000..dd148fa41d --- /dev/null +++ b/lib/srcdest_table.c @@ -0,0 +1,312 @@ +/* + * SRC-DEST Routing Table + * + * Copyright (C) 2017 by David Lamparter & Christian Franke, + * Open Source Routing / NetDEF Inc. + * + * This file is part of FreeRangeRouting (FRR) + * + * FRR is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * FRR is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with FRR; see the file COPYING. If not, write to the Free + * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA + * 02111-1307, USA. + */ + +#include <zebra.h> + +#include "srcdest_table.h" + +#include "memory.h" +#include "prefix.h" +#include "table.h" + +DEFINE_MTYPE_STATIC(LIB, ROUTE_SRC_NODE, "Route source node") + +/* ----- functions to manage rnodes _with_ srcdest table ----- */ +struct srcdest_rnode +{ + /* must be first in structure for casting to/from route_node */ + ROUTE_NODE_FIELDS; + + struct route_table *src_table; +}; + +static struct srcdest_rnode * +srcdest_rnode_from_rnode (struct route_node *rn) +{ + assert (rnode_is_dstnode (rn)); + return (struct srcdest_rnode *) rn; +} + +static struct route_node * +srcdest_rnode_to_rnode (struct srcdest_rnode *srn) +{ + return (struct route_node *) srn; +} + +static struct route_node * +srcdest_rnode_create (route_table_delegate_t *delegate, + struct route_table *table) +{ + struct srcdest_rnode *srn; + srn = XCALLOC (MTYPE_ROUTE_NODE, sizeof (struct srcdest_rnode)); + return srcdest_rnode_to_rnode(srn); +} + +static void +srcdest_rnode_destroy (route_table_delegate_t *delegate, + struct route_table *table, struct route_node *rn) +{ + struct srcdest_rnode *srn = srcdest_rnode_from_rnode(rn); + struct route_table *src_table; + + /* Clear route node's src_table here already, otherwise the + * deletion of the last node in the src_table will trigger + * another call to route_table_finish for the src_table. + * + * (Compare with srcdest_srcnode_destroy) + */ + src_table = srn->src_table; + srn->src_table = NULL; + route_table_finish(src_table); + XFREE (MTYPE_ROUTE_NODE, rn); +} + +route_table_delegate_t _srcdest_dstnode_delegate = { + .create_node = srcdest_rnode_create, + .destroy_node = srcdest_rnode_destroy +}; + +/* ----- functions to manage rnodes _in_ srcdest table ----- */ + +/* node creation / deletion for srcdest source prefix nodes. + * the route_node isn't actually different from the normal route_node, + * but the cleanup is special to free the table (and possibly the + * destination prefix's route_node) */ + +static struct route_node * +srcdest_srcnode_create (route_table_delegate_t *delegate, + struct route_table *table) +{ + return XCALLOC (MTYPE_ROUTE_SRC_NODE, sizeof (struct route_node)); +} + +static void +srcdest_srcnode_destroy (route_table_delegate_t *delegate, + struct route_table *table, struct route_node *rn) +{ + struct srcdest_rnode *srn; + + XFREE (MTYPE_ROUTE_SRC_NODE, rn); + + srn = table->info; + if (srn->src_table && route_table_count (srn->src_table) == 0) + { + /* deleting the route_table from inside destroy_node is ONLY + * permitted IF table->count is 0! see lib/table.c route_node_delete() + * for details */ + route_table_finish (srn->src_table); + srn->src_table = NULL; + + /* drop the ref we're holding in srcdest_node_get(). there might be + * non-srcdest routes, so the route_node may still exist. hence, it's + * important to clear src_table above. */ + route_unlock_node (srcdest_rnode_to_rnode (srn)); + } +} + +route_table_delegate_t _srcdest_srcnode_delegate = { + .create_node = srcdest_srcnode_create, + .destroy_node = srcdest_srcnode_destroy +}; + +/* NB: read comments in code for refcounting before using! */ +static struct route_node * +srcdest_srcnode_get (struct route_node *rn, struct prefix_ipv6 *src_p) +{ + struct srcdest_rnode *srn; + + if (!src_p || src_p->prefixlen == 0) + return rn; + + srn = srcdest_rnode_from_rnode (rn); + if (!srn->src_table) + { + /* this won't use srcdest_rnode, we're already on the source here */ + srn->src_table = route_table_init_with_delegate (&_srcdest_srcnode_delegate); + srn->src_table->info = srn; + + /* there is no route_unlock_node on the original rn here. + * The reference is kept for the src_table. */ + } + else + { + /* only keep 1 reference for the src_table, makes the refcounting + * more similar to the non-srcdest case. Either way after return from + * function, the only reference held is the one on the return value. + * + * We can safely drop our reference here because src_table is holding + * another reference, so this won't free rn */ + route_unlock_node (rn); + } + + return route_node_get (srn->src_table, (struct prefix *)src_p); +} + +static struct route_node * +srcdest_srcnode_lookup (struct route_node *rn, struct prefix_ipv6 *src_p) +{ + struct srcdest_rnode *srn; + + if (!rn || !src_p || src_p->prefixlen == 0) + return rn; + + /* We got this rn from a lookup, so its refcnt was incremented. As we won't + * return return rn from any point beyond here, we should decrement its refcnt. + */ + route_unlock_node (rn); + + srn = srcdest_rnode_from_rnode (rn); + if (!srn->src_table) + return NULL; + + return route_node_lookup (srn->src_table, (struct prefix *)src_p); +} + +/* ----- exported functions ----- */ + +struct route_table * +srcdest_table_init(void) +{ + return route_table_init_with_delegate(&_srcdest_dstnode_delegate); +} + +struct route_node * +srcdest_route_next(struct route_node *rn) +{ + struct route_node *next, *parent; + + /* For a non src-dest node, just return route_next */ + if (!(rnode_is_dstnode(rn) || rnode_is_srcnode(rn))) + return route_next(rn); + + if (rnode_is_dstnode(rn)) + { + /* This means the route_node is part of the top hierarchy + * and refers to a destination prefix. */ + struct srcdest_rnode *srn = srcdest_rnode_from_rnode(rn); + + if (srn->src_table) + next = route_top(srn->src_table); + else + next = NULL; + + if (next) + { + /* There is a source prefix. Return the node for it */ + route_unlock_node(rn); + return next; + } + else + { + /* There is no source prefix, just continue as usual */ + return route_next(rn); + } + } + + /* This part handles the case of iterating source nodes. */ + parent = route_lock_node(rn->table->info); + next = route_next(rn); + + if (next) + { + /* There is another source node, continue in the source table */ + route_unlock_node(parent); + return next; + } + else + { + /* The source table is complete, continue in the parent table */ + return route_next(parent); + } +} + +struct route_node * +srcdest_rnode_get (struct route_table *table, union prefix46ptr dst_pu, + struct prefix_ipv6 *src_p) +{ + struct prefix_ipv6 *dst_p = dst_pu.p6; + struct route_node *rn; + + rn = route_node_get (table, (struct prefix *) dst_p); + return srcdest_srcnode_get (rn, src_p); +} + +struct route_node * +srcdest_rnode_lookup (struct route_table *table, union prefix46ptr dst_pu, + struct prefix_ipv6 *src_p) +{ + struct prefix_ipv6 *dst_p = dst_pu.p6; + struct route_node *rn; + struct route_node *srn; + + rn = route_node_lookup_maynull (table, (struct prefix *) dst_p); + srn = srcdest_srcnode_lookup (rn, src_p); + + if (rn != NULL && rn == srn && !rn->info) + { + /* Match the behavior of route_node_lookup and don't return an + * empty route-node for a dest-route */ + route_unlock_node(rn); + return NULL; + } + return srn; +} + +void +srcdest_rnode_prefixes (struct route_node *rn, struct prefix **p, + struct prefix **src_p) +{ + if (rnode_is_srcnode (rn)) + { + struct route_node *dst_rn = rn->table->info; + if (p) + *p = &dst_rn->p; + if (src_p) + *src_p = &rn->p; + } + else + { + if (p) + *p = &rn->p; + if (src_p) + *src_p = NULL; + } +} + +const char * +srcdest_rnode2str (struct route_node *rn, char *str, int size) +{ + struct prefix *dst_p, *src_p; + char dst_buf[PREFIX_STRLEN], src_buf[PREFIX_STRLEN]; + + srcdest_rnode_prefixes(rn, &dst_p, &src_p); + + snprintf(str, size, "%s%s%s", + prefix2str(dst_p, dst_buf, sizeof(dst_buf)), + (src_p && src_p->prefixlen) ? " from " : "", + (src_p && src_p->prefixlen) ? prefix2str(src_p, src_buf, + sizeof(src_buf)) + : ""); + return str; +} |