/* * Linux INET6 implementation * Forwarding Information Database * * Authors: * Pedro Roque <roque@di.fc.ul.pt> * * $Id: ip6_fib.c,v 1.25 2001/10/31 21:55:55 davem Exp $ * * This program 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 of the License, or (at your option) any later version. */ /* * Changes: * Yuji SEKIYA @USAGI: Support default route on router node; * remove ip6_null_entry from the top of * routing table. * Ville Nuorvala: Fixed routing subtrees. */ #include <linux/errno.h> #include <linux/types.h> #include <linux/net.h> #include <linux/route.h> #include <linux/netdevice.h> #include <linux/in6.h> #include <linux/init.h> #include <linux/list.h> #ifdef CONFIG_PROC_FS #include <linux/proc_fs.h> #endif #include <net/ipv6.h> #include <net/ndisc.h> #include <net/addrconf.h> #include <net/ip6_fib.h> #include <net/ip6_route.h> #define RT6_DEBUG 2 #if RT6_DEBUG >= 3 #define RT6_TRACE(x...) printk(KERN_DEBUG x) #else #define RT6_TRACE(x...) do { ; } while (0) #endif struct rt6_statistics rt6_stats; static kmem_cache_t * fib6_node_kmem __read_mostly; enum fib_walk_state_t { #ifdef CONFIG_IPV6_SUBTREES FWS_S, #endif FWS_L, FWS_R, FWS_C, FWS_U }; struct fib6_cleaner_t { struct fib6_walker_t w; int (*func)(struct rt6_info *, void *arg); void *arg; }; static DEFINE_RWLOCK(fib6_walker_lock); #ifdef CONFIG_IPV6_SUBTREES #define FWS_INIT FWS_S #else #define FWS_INIT FWS_L #endif static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt); static struct rt6_info * fib6_find_prefix(struct fib6_node *fn); static struct fib6_node * fib6_repair_tree(struct fib6_node *fn); static int fib6_walk(struct fib6_walker_t *w); static int fib6_walk_continue(struct fib6_walker_t *w); /* * A routing update causes an increase of the serial number on the * affected subtree. This allows for cached routes to be asynchronously * tested when modifications are made to the destination cache as a * result of redirects, path MTU changes, etc. */ static __u32 rt_sernum; static DEFINE_TIMER(ip6_fib_timer, fib6_run_gc, 0, 0); static struct fib6_walker_t fib6_walker_list = { .prev = &fib6_walker_list, .next = &fib6_walker_list, }; #define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next) static inline void fib6_walker_link(struct fib6_walker_t *w) { write_lock_bh(&fib6_walker_lock); w->next = fib6_walker_list.next; w->prev = &fib6_walker_list; w->next->prev = w; w->prev->next = w; write_unlock_bh(&fib6_walker_lock); } static inline void fib6_walker_unlink(struct fib6_walker_t *w) { write_lock_bh(&fib6_walker_lock); w->next->prev = w->prev; w->prev->next = w->next; w->prev = w->next = w; write_unlock_bh(&fib6_walker_lock); } static __inline__ u32 fib6_new_sernum(void) { u32 n = ++rt_sernum; if ((__s32)n <= 0) rt_sernum = n = 1; return n; } /* * Auxiliary address test functions for the radix tree. * * These assume a 32bit processor (although it will work on * 64bit processors) */ /* * test bit */ static __inline__ int addr_bit_set(void *token, int fn_bit) { __u32 *addr = token; return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5]; } static __inline__ struct fib6_node * node_alloc(void) { struct fib6_node *fn; if ((fn = kmem_cache_alloc(fib6_node_kmem, SLAB_ATOMIC)) != NULL) memset(fn, 0, sizeof(struct fib6_node)); return fn; } static __inline__ void node_free(struct fib6_node * fn) { kmem_cache_free(fib6_node_kmem, fn); } static __inline__ void rt6_release(struct rt6_info *rt) { if (atomic_dec_and_test(&rt->rt6i_ref)) dst_free(&rt->u.dst); } static struct fib6_table fib6_main_tbl = { .tb6_id = RT6_TABLE_MAIN, .tb6_lock = RW_LOCK_UNLOCKED, .tb6_root = { .leaf = &ip6_null_entry, .fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO, }, }; #ifdef CONFIG_IPV6_MULTIPLE_TABLES #define FIB_TABLE_HASHSZ 256 #else #define FIB_TABLE_HASHSZ 1 #endif static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ]; static void fib6_link_table(struct fib6_table *tb) { unsigned int h; h = tb->tb6_id & (FIB_TABLE_HASHSZ - 1); /* * No protection necessary, this is the only list mutatation * operation, tables never disappear once they exist. */ hlist_add_head_rcu(&tb->tb6_hlist, &fib_table_hash[h]); } #ifdef CONFIG_IPV6_MULTIPLE_TABLES static struct fib6_table fib6_local_tbl = { .tb6_id = RT6_TABLE_LOCAL, .tb6_lock = RW_LOCK_UNLOCKED, .tb6_root = { .leaf = &ip6_null_entry, .fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO, }, }; static struct fib6_table *fib6_alloc_table(u32 id) { struct fib6_table *table; table = kzalloc(sizeof(*table), GFP_ATOMIC); if (table != NULL) { table->tb6_id = id; table->tb6_lock = RW_LOCK_UNLOCKED; table->tb6_root.leaf = &ip6_null_entry; table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO; } return table; } struct fib6_table *fib6_new_table(u32 id) { struct fib6_table *tb; if (id == 0) id = RT6_TABLE_MAIN; tb = fib6_get_table(id); if (tb) return tb; tb = fib6_alloc_table(id); if (tb != NULL) fib6_link_table(tb); return tb; } struct fib6_table *fib6_get_table(u32 id) { struct fib6_table *tb; struct hlist_node *node; unsigned int h; if (id == 0) id = RT6_TABLE_MAIN; h = id & (FIB_TABLE_HASHSZ - 1); rcu_read_lock(); hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb6_hlist) { if (tb->tb6_id == id) { rcu_read_unlock(); return tb; } } rcu_read_unlock(); return NULL; } static void __init fib6_tables_init(void) { fib6_link_table(&fib6_main_tbl); fib6_link_table(&fib6_local_tbl); } #else struct fib6_table *fib6_new_table(u32 id) { return fib6_get_table(id); } struct fib6_table *fib6_get_table(u32 id) { return &fib6_main_tbl; } struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags, pol_lookup_t lookup) { return (struct dst_entry *) lookup(&fib6_main_tbl, fl, flags); } static void __init fib6_tables_init(void) { fib6_link_table(&fib6_main_tbl); } #endif static int fib6_dump_node(struct fib6_walker_t *w) { int res; struct rt6_info *rt; for (rt = w->leaf; rt; rt = rt->u.next) { res = rt6_dump_route(rt, w->args); if (res < 0) { /* Frame is full, suspend walking */ w->leaf = rt; return 1; } BUG_TRAP(res!=0); } w->leaf = NULL; return 0; } static void fib6_dump_end(struct netlink_callback *cb) { struct fib6_walker_t *w = (void*)cb->args[2]; if (w) { cb->args[2] = 0; kfree(w); } cb->done = (void*)cb->args[3]; cb->args[1] = 3; } static int fib6_dump_done(struct netlink_callback *cb) { fib6_dump_end(cb); return cb->done ? cb->done(cb) : 0; } static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb, struct netlink_callback *cb) { struct fib6_walker_t *w; int res; w = (void *)cb->args[2]; w->root = &table->tb6_root; if (cb->args[4] == 0) { read_lock_bh(&table->tb6_lock); res = fib6_walk(w); read_unlock_bh(&table->tb6_lock); if (res > 0) cb->args[4] = 1; } else { read_lock_bh(&table->tb6_lock); res = fib6_walk_continue(w); read_unlock_bh(&table->tb6_lock); if (res != 0) { if (res < 0) fib6_walker_unlink(w); goto end; } fib6_walker_unlink(w); cb->args[4] = 0; } end: return res; } int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) { unsigned int h, s_h; unsigned int e = 0, s_e; struct rt6_rtnl_dump_arg arg; struct fib6_walker_t *w; struct fib6_table *tb; struct hlist_node *node; int res = 0; s_h = cb->args[0]; s_e = cb->args[1]; w = (void *)cb->args[2]; if (w == NULL) { /* New dump: * * 1. hook callback destructor. */ cb->args[3] = (long)cb->done; cb->done = fib6_dump_done; /* * 2. allocate and initialize walker. */ w = kzalloc(sizeof(*w), GFP_ATOMIC); if (w == NULL) return -ENOMEM; w->func = fib6_dump_node; cb->args[2] = (long)w; } arg.skb = skb; arg.cb = cb; w->args = &arg; for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) { e = 0; hlist_for_each_entry(tb, node, &fib_table_hash[h], tb6_hlist) { if (e < s_e) goto next; res = fib6_dump_table(tb, skb, cb); if (res != 0) goto out; next: e++; } } out: cb->args[1] = e; cb->args[0] = h; res = res < 0 ? res : skb->len; if (res <= 0) fib6_dump_end(cb); return res; } /* * Routing Table * * return the appropriate node for a routing tree "add" operation * by either creating and inserting or by returning an existing * node. */ static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, int addrlen, int plen, int offset) { struct fib6_node *fn, *in, *ln; struct fib6_node *pn = NULL; struct rt6key *key; int bit; int dir = 0; __u32 sernum = fib6_new_sernum(); RT6_TRACE("fib6_add_1\n"); /* insert node in tree */ fn = root; do { key = (struct rt6key *)((u8 *)fn->leaf + offset); /* * Prefix match */ if (plen < fn->fn_bit || !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) goto insert_above; /* * Exact match ? */ if (plen == fn->fn_bit) { /* clean up an intermediate node */ if ((fn->fn_flags & RTN_RTINFO) == 0) { rt6_release(fn->leaf); fn->leaf = NULL; } fn->fn_sernum = sernum; return fn; } /* * We have more bits to go */ /* Try to walk down on tree. */ fn->fn_sernum = sernum; dir = addr_bit_set(addr, fn->fn_bit); pn = fn; fn = dir ? fn->right: fn->left; } while (fn); /* * We walked to the bottom of tree. * Create new leaf node without children. */ ln = node_alloc(); if (ln == NULL) return NULL; ln->fn_bit = plen; ln->parent = pn; ln->fn_sernum = sernum; if (dir) pn->right = ln; else pn->left = ln; return ln; insert_above: /* * split since we don't have a common prefix anymore or * we have a less significant route. * we've to insert an intermediate node on the list * this new node will point to the one we need to create * and the current */ pn = fn->parent; /* find 1st bit in difference between the 2 addrs. See comment in __ipv6_addr_diff: bit may be an invalid value, but if it is >= plen, the value is ignored in any case. */ bit = __ipv6_addr_diff(addr, &key->addr, addrlen); /* * (intermediate)[in] * / \ * (new leaf node)[ln] (old node)[fn] */ if (plen > bit) { in = node_alloc(); ln = node_alloc(); if (in == NULL || ln == NULL) { if (in) node_free(in); if (ln) node_free(ln); return NULL; } /* * new intermediate node. * RTN_RTINFO will * be off since that an address that chooses one of * the branches would not match less specific routes * in the other branch */ in->fn_bit = bit; in->parent = pn; in->leaf = fn->leaf; atomic_inc(&in->leaf->rt6i_ref); in->fn_sernum = sernum; /* update parent pointer */ if (dir) pn->right = in; else pn->left = in; ln->fn_bit = plen; ln->parent = in; fn->parent = in; ln->fn_sernum = sernum; if (addr_bit_set(addr, bit)) { in->right = ln; in->left = fn; } else { in->left = ln; in->right = fn; } } else { /* plen <= bit */ /* * (new leaf node)[ln] * / \ * (old node)[fn] NULL */ ln = node_alloc(); if (ln == NULL) return NULL; ln->fn_bit = plen; ln->parent = pn; ln->fn_sernum = sernum; if (dir) pn->right = ln; else pn->left = ln; if (addr_bit_set(&key->addr, plen)) ln->right = fn; else ln->left = fn; fn->parent = ln; } return ln; } /* * Insert routing information in a node. */ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, struct nl_info *info) { struct rt6_info *iter = NULL; struct rt6_info **ins; ins = &fn->leaf; if (fn->fn_flags&RTN_TL_ROOT && fn->leaf == &ip6_null_entry && !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){ fn->leaf = rt; rt->u.next = NULL; goto out; } for (iter = fn->leaf; iter; iter=iter->u.next) { /* * Search for duplicates */ if (iter->rt6i_metric == rt->rt6i_metric) { /* * Same priority level */ if (iter->rt6i_dev == rt->rt6i_dev && iter->rt6i_idev == rt->rt6i_idev && ipv6_addr_equal(&iter->rt6i_gateway, &rt->rt6i_gateway)) { if (!(iter->rt6i_flags&RTF_EXPIRES)) return -EEXIST; iter->rt6i_expires = rt->rt6i_expires; if (!(rt->rt6i_flags&RTF_EXPIRES)) { iter->rt6i_flags &= ~RTF_EXPIRES; iter->rt6i_expires = 0; } return -EEXIST; } } if (iter->rt6i_metric > rt->rt6i_metric) break; ins = &iter->u.next; } /* * insert node */ out: rt->u.next = iter; *ins = rt; rt->rt6i_node = fn; atomic_inc(&rt->rt6i_ref); inet6_rt_notify(RTM_NEWROUTE, rt, info); rt6_stats.fib_rt_entries++; if ((fn->fn_flags & RTN_RTINFO) == 0) { rt6_stats.fib_route_nodes++; fn->fn_flags |= RTN_RTINFO; } return 0; } static __inline__ void fib6_start_gc(struct rt6_info *rt) { if (ip6_fib_timer.expires == 0 && (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE))) mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); } void fib6_force_start_gc(void) { if (ip6_fib_timer.expires == 0) mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); } /* * Add routing information to the routing tree. * <destination addr>/<source addr> * with source addr info in sub-trees */ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) { struct fib6_node *fn, *pn = NULL; int err = -ENOMEM; fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr), rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst)); if (fn == NULL) goto out; pn = fn; #ifdef CONFIG_IPV6_SUBTREES if (rt->rt6i_src.plen) { struct fib6_node *sn; if (fn->subtree == NULL) { struct fib6_node *sfn; /* * Create subtree. * * fn[main tree] * | * sfn[subtree root] * \ * sn[new leaf node] */ /* Create subtree root node */ sfn = node_alloc(); if (sfn == NULL) goto st_failure; sfn->leaf = &ip6_null_entry; atomic_inc(&ip6_null_entry.rt6i_ref); sfn->fn_flags = RTN_ROOT; sfn->fn_sernum = fib6_new_sernum(); /* Now add the first leaf node to new subtree */ sn = fib6_add_1(sfn, &rt->rt6i_src.addr, sizeof(struct in6_addr), rt->rt6i_src.plen, offsetof(struct rt6_info, rt6i_src)); if (sn == NULL) { /* If it is failed, discard just allocated root, and then (in st_failure) stale node in main tree. */ node_free(sfn); goto st_failure; } /* Now link new subtree to main tree */ sfn->parent = fn; fn->subtree = sfn; } else { sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr, sizeof(struct in6_addr), rt->rt6i_src.plen, offsetof(struct rt6_info, rt6i_src)); if (sn == NULL) goto st_failure; } if (fn->leaf == NULL) { fn->leaf = rt; atomic_inc(&rt->rt6i_ref); } fn = sn; } #endif err = fib6_add_rt2node(fn, rt, info); if (err == 0) { fib6_start_gc(rt); if (!(rt->rt6i_flags&RTF_CACHE)) fib6_prune_clones(pn, rt); } out: if (err) { #ifdef CONFIG_IPV6_SUBTREES /* * If fib6_add_1 has cleared the old leaf pointer in the * super-tree leaf node we have to find a new one for it. */ if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) { pn->leaf = fib6_find_prefix(pn); #if RT6_DEBUG >= 2 if (!pn->leaf) { BUG_TRAP(pn->leaf != NULL); pn->leaf = &ip6_null_entry; } #endif atomic_inc(&pn->leaf->rt6i_ref); } #endif dst_free(&rt->u.dst); } return err; #ifdef CONFIG_IPV6_SUBTREES /* Subtree creation failed, probably main tree node is orphan. If it is, shoot it. */ st_failure: if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT))) fib6_repair_tree(fn); dst_free(&rt->u.dst); return err; #endif } /* * Routing tree lookup * */ struct lookup_args { int offset; /* key offset on rt6_info */ struct in6_addr *addr; /* search key */ }; static struct fib6_node * fib6_lookup_1(struct fib6_node *root, struct lookup_args *args) { struct fib6_node *fn; int dir; if (unlikely(args->offset == 0)) return NULL; /* * Descend on a tree */ fn = root; for (;;) { struct fib6_node *next; dir = addr_bit_set(args->addr, fn->fn_bit); next = dir ? fn->right : fn->left; if (next) { fn = next; continue; } break; } while(fn) { if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) { struct rt6key *key; key = (struct rt6key *) ((u8 *) fn->leaf + args->offset); if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) { #ifdef CONFIG_IPV6_SUBTREES if (fn->subtree) fn = fib6_lookup_1(fn->subtree, args + 1); #endif if (!fn || fn->fn_flags & RTN_RTINFO) return fn; } } if (fn->fn_flags & RTN_ROOT) break; fn = fn->parent; } return NULL; } struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr, struct in6_addr *saddr) { struct fib6_node *fn; struct lookup_args args[] = { { .offset = offsetof(struct rt6_info, rt6i_dst), .addr = daddr, }, #ifdef CONFIG_IPV6_SUBTREES { .offset = offsetof(struct rt6_info, rt6i_src), .addr = saddr, }, #endif { .offset = 0, /* sentinel */ } }; fn = fib6_lookup_1(root, daddr ? args : args + 1); if (fn == NULL || fn->fn_flags & RTN_TL_ROOT) fn = root; return fn; } /* * Get node with specified destination prefix (and source prefix, * if subtrees are used) */ static struct fib6_node * fib6_locate_1(struct fib6_node *root, struct in6_addr *addr, int plen, int offset) { struct fib6_node *fn; for (fn = root; fn ; ) { struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset); /* * Prefix match */ if (plen < fn->fn_bit || !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) return NULL; if (plen == fn->fn_bit) return fn; /* * We have more bits to go */ if (addr_bit_set(addr, fn->fn_bit)) fn = fn->right; else fn = fn->left; } return NULL; } struct fib6_node * fib6_locate(struct fib6_node *root, struct in6_addr *daddr, int dst_len, struct in6_addr *saddr, int src_len) { struct fib6_node *fn; fn = fib6_locate_1(root, daddr, dst_len, offsetof(struct rt6_info, rt6i_dst)); #ifdef CONFIG_IPV6_SUBTREES if (src_len) { BUG_TRAP(saddr!=NULL); if (fn && fn->subtree) fn = fib6_locate_1(fn->subtree, saddr, src_len, offsetof(struct rt6_info, rt6i_src)); } #endif if (fn && fn->fn_flags&RTN_RTINFO) return fn; return NULL; } /* * Deletion * */ static struct rt6_info * fib6_find_prefix(struct fib6_node *fn) { if (fn->fn_flags&RTN_ROOT) return &ip6_null_entry; while(fn) { if(fn->left) return fn->left->leaf; if(fn->right) return fn->right->leaf; fn = FIB6_SUBTREE(fn); } return NULL; } /* * Called to trim the tree of intermediate nodes when possible. "fn" * is the node we want to try and remove. */ static struct fib6_node * fib6_repair_tree(struct fib6_node *fn) { int children; int nstate; struct fib6_node *child, *pn; struct fib6_walker_t *w; int iter = 0; for (;;) { RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter); iter++; BUG_TRAP(!(fn->fn_flags&RTN_RTINFO)); BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT)); BUG_TRAP(fn->leaf==NULL); children = 0; child = NULL; if (fn->right) child = fn->right, children |= 1; if (fn->left) child = fn->left, children |= 2; if (children == 3 || FIB6_SUBTREE(fn) #ifdef CONFIG_IPV6_SUBTREES /* Subtree root (i.e. fn) may have one child */ || (children && fn->fn_flags&RTN_ROOT) #endif ) { fn->leaf = fib6_find_prefix(fn); #if RT6_DEBUG >= 2 if (fn->leaf==NULL) { BUG_TRAP(fn->leaf); fn->leaf = &ip6_null_entry; } #endif atomic_inc(&fn->leaf->rt6i_ref); return fn->parent; } pn = fn->parent; #ifdef CONFIG_IPV6_SUBTREES if (FIB6_SUBTREE(pn) == fn) { BUG_TRAP(fn->fn_flags&RTN_ROOT); FIB6_SUBTREE(pn) = NULL; nstate = FWS_L; } else { BUG_TRAP(!(fn->fn_flags&RTN_ROOT)); #endif if (pn->right == fn) pn->right = child; else if (pn->left == fn) pn->left = child; #if RT6_DEBUG >= 2 else BUG_TRAP(0); #endif if (child) child->parent = pn; nstate = FWS_R; #ifdef CONFIG_IPV6_SUBTREES } #endif read_lock(&fib6_walker_lock); FOR_WALKERS(w) { if (child == NULL) { if (w->root == fn) { w->root = w->node = NULL; RT6_TRACE("W %p adjusted by delroot 1\n", w); } else if (w->node == fn) { RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate); w->node = pn; w->state = nstate; } } else { if (w->root == fn) { w->root = child; RT6_TRACE("W %p adjusted by delroot 2\n", w); } if (w->node == fn) { w->node = child; if (children&2) { RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); w->state = w->state>=FWS_R ? FWS_U : FWS_INIT; } else { RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); w->state = w->state>=FWS_C ? FWS_U : FWS_INIT; } } } } read_unlock(&fib6_walker_lock); node_free(fn); if (pn->fn_flags&RTN_RTINFO || FIB6_SUBTREE(pn)) return pn; rt6_release(pn->leaf); pn->leaf = NULL; fn = pn; } } static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp, struct nl_info *info) { struct fib6_walker_t *w; struct rt6_info *rt = *rtp; RT6_TRACE("fib6_del_route\n"); /* Unlink it */ *rtp = rt->u.next; rt->rt6i_node = NULL; rt6_stats.fib_rt_entries--; rt6_stats.fib_discarded_routes++; /* Adjust walkers */ read_lock(&fib6_walker_lock); FOR_WALKERS(w) { if (w->state == FWS_C && w->leaf == rt) { RT6_TRACE("walker %p adjusted by delroute\n", w); w->leaf = rt->u.next; if (w->leaf == NULL) w->state = FWS_U; } } read_unlock(&fib6_walker_lock); rt->u.next = NULL; if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT) fn->leaf = &ip6_null_entry; /* If it was last route, expunge its radix tree node */ if (fn->leaf == NULL) { fn->fn_flags &= ~RTN_RTINFO; rt6_stats.fib_route_nodes--; fn = fib6_repair_tree(fn); } if (atomic_read(&rt->rt6i_ref) != 1) { /* This route is used as dummy address holder in some split * nodes. It is not leaked, but it still holds other resources, * which must be released in time. So, scan ascendant nodes * and replace dummy references to this route with references * to still alive ones. */ while (fn) { if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) { fn->leaf = fib6_find_prefix(fn); atomic_inc(&fn->leaf->rt6i_ref); rt6_release(rt); } fn = fn->parent; } /* No more references are possible at this point. */ if (atomic_read(&rt->rt6i_ref) != 1) BUG(); } inet6_rt_notify(RTM_DELROUTE, rt, info); rt6_release(rt); } int fib6_del(struct rt6_info *rt, struct nl_info *info) { struct fib6_node *fn = rt->rt6i_node; struct rt6_info **rtp; #if RT6_DEBUG >= 2 if (rt->u.dst.obsolete>0) { BUG_TRAP(fn==NULL); return -ENOENT; } #endif if (fn == NULL || rt == &ip6_null_entry) return -ENOENT; BUG_TRAP(fn->fn_flags&RTN_RTINFO); if (!(rt->rt6i_flags&RTF_CACHE)) { struct fib6_node *pn = fn; #ifdef CONFIG_IPV6_SUBTREES /* clones of this route might be in another subtree */ if (rt->rt6i_src.plen) { while (!(pn->fn_flags&RTN_ROOT)) pn = pn->parent; pn = pn->parent; } #endif fib6_prune_clones(pn, rt); } /* * Walk the leaf entries looking for ourself */ for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.next) { if (*rtp == rt) { fib6_del_route(fn, rtp, info); return 0; } } return -ENOENT; } /* * Tree traversal function. * * Certainly, it is not interrupt safe. * However, it is internally reenterable wrt itself and fib6_add/fib6_del. * It means, that we can modify tree during walking * and use this function for garbage collection, clone pruning, * cleaning tree when a device goes down etc. etc. * * It guarantees that every node will be traversed, * and that it will be traversed only once. * * Callback function w->func may return: * 0 -> continue walking. * positive value -> walking is suspended (used by tree dumps, * and probably by gc, if it will be split to several slices) * negative value -> terminate walking. * * The function itself returns: * 0 -> walk is complete. * >0 -> walk is incomplete (i.e. suspended) * <0 -> walk is terminated by an error. */ static int fib6_walk_continue(struct fib6_walker_t *w) { struct fib6_node *fn, *pn; for (;;) { fn = w->node; if (fn == NULL) return 0; if (w->prune && fn != w->root && fn->fn_flags&RTN_RTINFO && w->state < FWS_C) { w->state = FWS_C; w->leaf = fn->leaf; } switch (w->state) { #ifdef CONFIG_IPV6_SUBTREES case FWS_S: if (FIB6_SUBTREE(fn)) { w->node = FIB6_SUBTREE(fn); continue; } w->state = FWS_L; #endif case FWS_L: if (fn->left) { w->node = fn->left; w->state = FWS_INIT; continue; } w->state = FWS_R; case FWS_R: if (fn->right) { w->node = fn->right; w->state = FWS_INIT; continue; } w->state = FWS_C; w->leaf = fn->leaf; case FWS_C: if (w->leaf && fn->fn_flags&RTN_RTINFO) { int err = w->func(w); if (err) return err; continue; } w->state = FWS_U; case FWS_U: if (fn == w->root) return 0; pn = fn->parent; w->node = pn; #ifdef CONFIG_IPV6_SUBTREES if (FIB6_SUBTREE(pn) == fn) { BUG_TRAP(fn->fn_flags&RTN_ROOT); w->state = FWS_L; continue; } #endif if (pn->left == fn) { w->state = FWS_R; continue; } if (pn->right == fn) { w->state = FWS_C; w->leaf = w->node->leaf; continue; } #if RT6_DEBUG >= 2 BUG_TRAP(0); #endif } } } static int fib6_walk(struct fib6_walker_t *w) { int res; w->state = FWS_INIT; w->node = w->root; fib6_walker_link(w); res = fib6_walk_continue(w); if (res <= 0) fib6_walker_unlink(w); return res; } static int fib6_clean_node(struct fib6_walker_t *w) { int res; struct rt6_info *rt; struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w; for (rt = w->leaf; rt; rt = rt->u.next) { res = c->func(rt, c->arg); if (res < 0) { w->leaf = rt; res = fib6_del(rt, NULL); if (res) { #if RT6_DEBUG >= 2 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res); #endif continue; } return 0; } BUG_TRAP(res==0); } w->leaf = rt; return 0; } /* * Convenient frontend to tree walker. * * func is called on each route. * It may return -1 -> delete this route. * 0 -> continue walking * * prune==1 -> only immediate children of node (certainly, * ignoring pure split nodes) will be scanned. */ static void fib6_clean_tree(struct fib6_node *root, int (*func)(struct rt6_info *, void *arg), int prune, void *arg) { struct fib6_cleaner_t c; c.w.root = root; c.w.func = fib6_clean_node; c.w.prune = prune; c.func = func; c.arg = arg; fib6_walk(&c.w); } void fib6_clean_all(int (*func)(struct rt6_info *, void *arg), int prune, void *arg) { struct fib6_table *table; struct hlist_node *node; unsigned int h; rcu_read_lock(); for (h = 0; h < FIB_TABLE_HASHSZ; h++) { hlist_for_each_entry_rcu(table, node, &fib_table_hash[h], tb6_hlist) { write_lock_bh(&table->tb6_lock); fib6_clean_tree(&table->tb6_root, func, prune, arg); write_unlock_bh(&table->tb6_lock); } } rcu_read_unlock(); } static int fib6_prune_clone(struct rt6_info *rt, void *arg) { if (rt->rt6i_flags & RTF_CACHE) { RT6_TRACE("pruning clone %p\n", rt); return -1; } return 0; } static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt) { fib6_clean_tree(fn, fib6_prune_clone, 1, rt); } /* * Garbage collection */ static struct fib6_gc_args { int timeout; int more; } gc_args; static int fib6_age(struct rt6_info *rt, void *arg) { unsigned long now = jiffies; /* * check addrconf expiration here. * Routes are expired even if they are in use. * * Also age clones. Note, that clones are aged out * only if they are not in use now. */ if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) { if (time_after(now, rt->rt6i_expires)) { RT6_TRACE("expiring %p\n", rt); return -1; } gc_args.more++; } else if (rt->rt6i_flags & RTF_CACHE) { if (atomic_read(&rt->u.dst.__refcnt) == 0 && time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) { RT6_TRACE("aging clone %p\n", rt); return -1; } else if ((rt->rt6i_flags & RTF_GATEWAY) && (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) { RT6_TRACE("purging route %p via non-router but gateway\n", rt); return -1; } gc_args.more++; } return 0; } static DEFINE_SPINLOCK(fib6_gc_lock); void fib6_run_gc(unsigned long dummy) { if (dummy != ~0UL) { spin_lock_bh(&fib6_gc_lock); gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval; } else { local_bh_disable(); if (!spin_trylock(&fib6_gc_lock)) { mod_timer(&ip6_fib_timer, jiffies + HZ); local_bh_enable(); return; } gc_args.timeout = ip6_rt_gc_interval; } gc_args.more = 0; ndisc_dst_gc(&gc_args.more); fib6_clean_all(fib6_age, 0, NULL); if (gc_args.more) mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); else { del_timer(&ip6_fib_timer); ip6_fib_timer.expires = 0; } spin_unlock_bh(&fib6_gc_lock); } void __init fib6_init(void) { fib6_node_kmem = kmem_cache_create("fib6_nodes", sizeof(struct fib6_node), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); fib6_tables_init(); } void fib6_gc_cleanup(void) { del_timer(&ip6_fib_timer); kmem_cache_destroy(fib6_node_kmem); }