diff options
Diffstat (limited to 'net/ipv6/ip6_fib.c')
| -rw-r--r-- | net/ipv6/ip6_fib.c | 1225 |
1 files changed, 1225 insertions, 0 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c new file mode 100644 index 0000000..405740b --- /dev/null +++ b/net/ipv6/ip6_fib.c @@ -0,0 +1,1225 @@ +/* + * 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. + */ +#include <linux/config.h> +#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> + +#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; + +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; +}; + +DEFINE_RWLOCK(fib6_walker_lock); + + +#ifdef CONFIG_IPV6_SUBTREES +#define FWS_INIT FWS_S +#define SUBTREE(fn) ((fn)->subtree) +#else +#define FWS_INIT FWS_L +#define SUBTREE(fn) NULL +#endif + +static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt); +static struct fib6_node * fib6_repair_tree(struct fib6_node *fn); + +/* + * 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 struct timer_list ip6_fib_timer = TIMER_INITIALIZER(fib6_run_gc, 0, 0); + +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__ 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]; +} + +/* + * find the first different bit between two addresses + * length of address must be a multiple of 32bits + */ + +static __inline__ int addr_diff(void *token1, void *token2, int addrlen) +{ + __u32 *a1 = token1; + __u32 *a2 = token2; + int i; + + addrlen >>= 2; + + for (i = 0; i < addrlen; i++) { + __u32 xb; + + xb = a1[i] ^ a2[i]; + + if (xb) { + int j = 31; + + xb = ntohl(xb); + + while ((xb & (1 << j)) == 0) + j--; + + return (i * 32 + 31 - j); + } + } + + /* + * we should *never* get to this point since that + * would mean the addrs are equal + * + * However, we do get to it 8) And exacly, when + * addresses are equal 8) + * + * ip route add 1111::/128 via ... + * ip route add 1111::/64 via ... + * and we are here. + * + * Ideally, this function should stop comparison + * at prefix length. It does not, but it is still OK, + * if returned value is greater than prefix length. + * --ANK (980803) + */ + + return addrlen<<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); +} + + +/* + * 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 addr_diff: bit may be an invalid value, + but if it is >= plen, the value is ignored in any case. + */ + + bit = 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 nlmsghdr *nlh) +{ + 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, nlh); + 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 nlmsghdr *nlh, void *_rtattr) +{ + struct fib6_node *fn; + 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; + +#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; + if (fn->leaf == NULL) { + fn->leaf = rt; + atomic_inc(&rt->rt6i_ref); + } + } 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; + } + + fn = sn; + } +#endif + + err = fib6_add_rt2node(fn, rt, nlh); + + if (err == 0) { + fib6_start_gc(rt); + if (!(rt->rt6i_flags&RTF_CACHE)) + fib6_prune_clones(fn, rt); + } + +out: + if (err) + 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; + + /* + * 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->fn_flags & RTN_ROOT) == 0) { +#ifdef CONFIG_IPV6_SUBTREES + if (fn->subtree) { + struct fib6_node *st; + struct lookup_args *narg; + + narg = args + 1; + + if (narg->addr) { + st = fib6_lookup_1(fn->subtree, narg); + + if (st && !(st->fn_flags & RTN_ROOT)) + return st; + } + } +#endif + + if (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)) + return fn; + } + + fn = fn->parent; + } + + return NULL; +} + +struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr, + struct in6_addr *saddr) +{ + struct lookup_args args[2]; + struct fib6_node *fn; + + args[0].offset = offsetof(struct rt6_info, rt6i_dst); + args[0].addr = daddr; + +#ifdef CONFIG_IPV6_SUBTREES + args[1].offset = offsetof(struct rt6_info, rt6i_src); + args[1].addr = saddr; +#endif + + fn = fib6_lookup_1(root, args); + + 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 == NULL) + fn = fn->subtree; + if (fn) + fn = fib6_locate_1(fn, 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 = 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 || 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 (SUBTREE(pn) == fn) { + BUG_TRAP(fn->fn_flags&RTN_ROOT); + 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 || 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 nlmsghdr *nlh, void *_rtattr) +{ + 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, nlh); + rt6_release(rt); +} + +int fib6_del(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr) +{ + 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)) + fib6_prune_clones(fn, 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, nlh, _rtattr); + 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. + */ + +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 (SUBTREE(fn)) { + w->node = 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 (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 + } + } +} + +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, 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. + */ + +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); +} + +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); + rt6_reset_dflt_pointer(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; + + + write_lock_bh(&rt6_lock); + ndisc_dst_gc(&gc_args.more); + fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL); + write_unlock_bh(&rt6_lock); + + 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, + NULL, NULL); + if (!fib6_node_kmem) + panic("cannot create fib6_nodes cache"); +} + +void fib6_gc_cleanup(void) +{ + del_timer(&ip6_fib_timer); + kmem_cache_destroy(fib6_node_kmem); +} |
