diff options
Diffstat (limited to 'net/ipv4/route.c')
| -rw-r--r-- | net/ipv4/route.c | 3510 |
1 files changed, 3510 insertions, 0 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c new file mode 100644 index 00000000..167ea10b --- /dev/null +++ b/net/ipv4/route.c @@ -0,0 +1,3510 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * ROUTE - implementation of the IP router. + * + * Authors: Ross Biro + * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> + * Alan Cox, <gw4pts@gw4pts.ampr.org> + * Linus Torvalds, <Linus.Torvalds@helsinki.fi> + * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> + * + * Fixes: + * Alan Cox : Verify area fixes. + * Alan Cox : cli() protects routing changes + * Rui Oliveira : ICMP routing table updates + * (rco@di.uminho.pt) Routing table insertion and update + * Linus Torvalds : Rewrote bits to be sensible + * Alan Cox : Added BSD route gw semantics + * Alan Cox : Super /proc >4K + * Alan Cox : MTU in route table + * Alan Cox : MSS actually. Also added the window + * clamper. + * Sam Lantinga : Fixed route matching in rt_del() + * Alan Cox : Routing cache support. + * Alan Cox : Removed compatibility cruft. + * Alan Cox : RTF_REJECT support. + * Alan Cox : TCP irtt support. + * Jonathan Naylor : Added Metric support. + * Miquel van Smoorenburg : BSD API fixes. + * Miquel van Smoorenburg : Metrics. + * Alan Cox : Use __u32 properly + * Alan Cox : Aligned routing errors more closely with BSD + * our system is still very different. + * Alan Cox : Faster /proc handling + * Alexey Kuznetsov : Massive rework to support tree based routing, + * routing caches and better behaviour. + * + * Olaf Erb : irtt wasn't being copied right. + * Bjorn Ekwall : Kerneld route support. + * Alan Cox : Multicast fixed (I hope) + * Pavel Krauz : Limited broadcast fixed + * Mike McLagan : Routing by source + * Alexey Kuznetsov : End of old history. Split to fib.c and + * route.c and rewritten from scratch. + * Andi Kleen : Load-limit warning messages. + * Vitaly E. Lavrov : Transparent proxy revived after year coma. + * Vitaly E. Lavrov : Race condition in ip_route_input_slow. + * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. + * Vladimir V. Ivanov : IP rule info (flowid) is really useful. + * Marc Boucher : routing by fwmark + * Robert Olsson : Added rt_cache statistics + * Arnaldo C. Melo : Convert proc stuff to seq_file + * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. + * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect + * Ilia Sotnikov : Removed TOS from hash calculations + * + * 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. + */ + +#define pr_fmt(fmt) "IPv4: " fmt + +#include <linux/module.h> +#include <asm/uaccess.h> +#include <linux/bitops.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/bootmem.h> +#include <linux/string.h> +#include <linux/socket.h> +#include <linux/sockios.h> +#include <linux/errno.h> +#include <linux/in.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/proc_fs.h> +#include <linux/init.h> +#include <linux/workqueue.h> +#include <linux/skbuff.h> +#include <linux/inetdevice.h> +#include <linux/igmp.h> +#include <linux/pkt_sched.h> +#include <linux/mroute.h> +#include <linux/netfilter_ipv4.h> +#include <linux/random.h> +#include <linux/jhash.h> +#include <linux/rcupdate.h> +#include <linux/times.h> +#include <linux/slab.h> +#include <linux/prefetch.h> +#include <net/dst.h> +#include <net/net_namespace.h> +#include <net/protocol.h> +#include <net/ip.h> +#include <net/route.h> +#include <net/inetpeer.h> +#include <net/sock.h> +#include <net/ip_fib.h> +#include <net/arp.h> +#include <net/tcp.h> +#include <net/icmp.h> +#include <net/xfrm.h> +#include <net/netevent.h> +#include <net/rtnetlink.h> +#ifdef CONFIG_SYSCTL +#include <linux/sysctl.h> +#endif +#include <net/secure_seq.h> + +#define RT_FL_TOS(oldflp4) \ + ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) + +#define IP_MAX_MTU 0xFFF0 + +#define RT_GC_TIMEOUT (300*HZ) + +static int ip_rt_max_size; +static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; +static int ip_rt_gc_interval __read_mostly = 60 * HZ; +static int ip_rt_gc_min_interval __read_mostly = HZ / 2; +static int ip_rt_redirect_number __read_mostly = 9; +static int ip_rt_redirect_load __read_mostly = HZ / 50; +static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); +static int ip_rt_error_cost __read_mostly = HZ; +static int ip_rt_error_burst __read_mostly = 5 * HZ; +static int ip_rt_gc_elasticity __read_mostly = 8; +static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; +static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; +static int ip_rt_min_advmss __read_mostly = 256; +static int rt_chain_length_max __read_mostly = 20; + +static struct delayed_work expires_work; +static unsigned long expires_ljiffies; + +/* + * Interface to generic destination cache. + */ + +static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); +static unsigned int ipv4_default_advmss(const struct dst_entry *dst); +static unsigned int ipv4_mtu(const struct dst_entry *dst); +static void ipv4_dst_destroy(struct dst_entry *dst); +static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); +static void ipv4_link_failure(struct sk_buff *skb); +static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu); +static int rt_garbage_collect(struct dst_ops *ops); + +static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, + int how) +{ +} + +static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) +{ + struct rtable *rt = (struct rtable *) dst; + struct inet_peer *peer; + u32 *p = NULL; + + if (!rt->peer) + rt_bind_peer(rt, rt->rt_dst, 1); + + peer = rt->peer; + if (peer) { + u32 *old_p = __DST_METRICS_PTR(old); + unsigned long prev, new; + + p = peer->metrics; + if (inet_metrics_new(peer)) + memcpy(p, old_p, sizeof(u32) * RTAX_MAX); + + new = (unsigned long) p; + prev = cmpxchg(&dst->_metrics, old, new); + + if (prev != old) { + p = __DST_METRICS_PTR(prev); + if (prev & DST_METRICS_READ_ONLY) + p = NULL; + } else { + if (rt->fi) { + fib_info_put(rt->fi); + rt->fi = NULL; + } + } + } + return p; +} + +static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr); + +static struct dst_ops ipv4_dst_ops = { + .family = AF_INET, + .protocol = cpu_to_be16(ETH_P_IP), + .gc = rt_garbage_collect, + .check = ipv4_dst_check, + .default_advmss = ipv4_default_advmss, + .mtu = ipv4_mtu, + .cow_metrics = ipv4_cow_metrics, + .destroy = ipv4_dst_destroy, + .ifdown = ipv4_dst_ifdown, + .negative_advice = ipv4_negative_advice, + .link_failure = ipv4_link_failure, + .update_pmtu = ip_rt_update_pmtu, + .local_out = __ip_local_out, + .neigh_lookup = ipv4_neigh_lookup, +}; + +#define ECN_OR_COST(class) TC_PRIO_##class + +const __u8 ip_tos2prio[16] = { + TC_PRIO_BESTEFFORT, + ECN_OR_COST(BESTEFFORT), + TC_PRIO_BESTEFFORT, + ECN_OR_COST(BESTEFFORT), + TC_PRIO_BULK, + ECN_OR_COST(BULK), + TC_PRIO_BULK, + ECN_OR_COST(BULK), + TC_PRIO_INTERACTIVE, + ECN_OR_COST(INTERACTIVE), + TC_PRIO_INTERACTIVE, + ECN_OR_COST(INTERACTIVE), + TC_PRIO_INTERACTIVE_BULK, + ECN_OR_COST(INTERACTIVE_BULK), + TC_PRIO_INTERACTIVE_BULK, + ECN_OR_COST(INTERACTIVE_BULK) +}; + + +/* + * Route cache. + */ + +/* The locking scheme is rather straight forward: + * + * 1) Read-Copy Update protects the buckets of the central route hash. + * 2) Only writers remove entries, and they hold the lock + * as they look at rtable reference counts. + * 3) Only readers acquire references to rtable entries, + * they do so with atomic increments and with the + * lock held. + */ + +struct rt_hash_bucket { + struct rtable __rcu *chain; +}; + +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \ + defined(CONFIG_PROVE_LOCKING) +/* + * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks + * The size of this table is a power of two and depends on the number of CPUS. + * (on lockdep we have a quite big spinlock_t, so keep the size down there) + */ +#ifdef CONFIG_LOCKDEP +# define RT_HASH_LOCK_SZ 256 +#else +# if NR_CPUS >= 32 +# define RT_HASH_LOCK_SZ 4096 +# elif NR_CPUS >= 16 +# define RT_HASH_LOCK_SZ 2048 +# elif NR_CPUS >= 8 +# define RT_HASH_LOCK_SZ 1024 +# elif NR_CPUS >= 4 +# define RT_HASH_LOCK_SZ 512 +# else +# define RT_HASH_LOCK_SZ 256 +# endif +#endif + +static spinlock_t *rt_hash_locks; +# define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)] + +static __init void rt_hash_lock_init(void) +{ + int i; + + rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ, + GFP_KERNEL); + if (!rt_hash_locks) + panic("IP: failed to allocate rt_hash_locks\n"); + + for (i = 0; i < RT_HASH_LOCK_SZ; i++) + spin_lock_init(&rt_hash_locks[i]); +} +#else +# define rt_hash_lock_addr(slot) NULL + +static inline void rt_hash_lock_init(void) +{ +} +#endif + +static struct rt_hash_bucket *rt_hash_table __read_mostly; +static unsigned rt_hash_mask __read_mostly; +static unsigned int rt_hash_log __read_mostly; + +static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); +#define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field) + +static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx, + int genid) +{ + return jhash_3words((__force u32)daddr, (__force u32)saddr, + idx, genid) + & rt_hash_mask; +} + +static inline int rt_genid(struct net *net) +{ + return atomic_read(&net->ipv4.rt_genid); +} + +#ifdef CONFIG_PROC_FS +struct rt_cache_iter_state { + struct seq_net_private p; + int bucket; + int genid; +}; + +static struct rtable *rt_cache_get_first(struct seq_file *seq) +{ + struct rt_cache_iter_state *st = seq->private; + struct rtable *r = NULL; + + for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) { + if (!rcu_access_pointer(rt_hash_table[st->bucket].chain)) + continue; + rcu_read_lock_bh(); + r = rcu_dereference_bh(rt_hash_table[st->bucket].chain); + while (r) { + if (dev_net(r->dst.dev) == seq_file_net(seq) && + r->rt_genid == st->genid) + return r; + r = rcu_dereference_bh(r->dst.rt_next); + } + rcu_read_unlock_bh(); + } + return r; +} + +static struct rtable *__rt_cache_get_next(struct seq_file *seq, + struct rtable *r) +{ + struct rt_cache_iter_state *st = seq->private; + + r = rcu_dereference_bh(r->dst.rt_next); + while (!r) { + rcu_read_unlock_bh(); + do { + if (--st->bucket < 0) + return NULL; + } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain)); + rcu_read_lock_bh(); + r = rcu_dereference_bh(rt_hash_table[st->bucket].chain); + } + return r; +} + +static struct rtable *rt_cache_get_next(struct seq_file *seq, + struct rtable *r) +{ + struct rt_cache_iter_state *st = seq->private; + while ((r = __rt_cache_get_next(seq, r)) != NULL) { + if (dev_net(r->dst.dev) != seq_file_net(seq)) + continue; + if (r->rt_genid == st->genid) + break; + } + return r; +} + +static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos) +{ + struct rtable *r = rt_cache_get_first(seq); + + if (r) + while (pos && (r = rt_cache_get_next(seq, r))) + --pos; + return pos ? NULL : r; +} + +static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct rt_cache_iter_state *st = seq->private; + if (*pos) + return rt_cache_get_idx(seq, *pos - 1); + st->genid = rt_genid(seq_file_net(seq)); + return SEQ_START_TOKEN; +} + +static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct rtable *r; + + if (v == SEQ_START_TOKEN) + r = rt_cache_get_first(seq); + else + r = rt_cache_get_next(seq, v); + ++*pos; + return r; +} + +static void rt_cache_seq_stop(struct seq_file *seq, void *v) +{ + if (v && v != SEQ_START_TOKEN) + rcu_read_unlock_bh(); +} + +static int rt_cache_seq_show(struct seq_file *seq, void *v) +{ + if (v == SEQ_START_TOKEN) + seq_printf(seq, "%-127s\n", + "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" + "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" + "HHUptod\tSpecDst"); + else { + struct rtable *r = v; + struct neighbour *n; + int len, HHUptod; + + rcu_read_lock(); + n = dst_get_neighbour_noref(&r->dst); + HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0; + rcu_read_unlock(); + + seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t" + "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n", + r->dst.dev ? r->dst.dev->name : "*", + (__force u32)r->rt_dst, + (__force u32)r->rt_gateway, + r->rt_flags, atomic_read(&r->dst.__refcnt), + r->dst.__use, 0, (__force u32)r->rt_src, + dst_metric_advmss(&r->dst) + 40, + dst_metric(&r->dst, RTAX_WINDOW), + (int)((dst_metric(&r->dst, RTAX_RTT) >> 3) + + dst_metric(&r->dst, RTAX_RTTVAR)), + r->rt_key_tos, + -1, + HHUptod, + r->rt_spec_dst, &len); + + seq_printf(seq, "%*s\n", 127 - len, ""); + } + return 0; +} + +static const struct seq_operations rt_cache_seq_ops = { + .start = rt_cache_seq_start, + .next = rt_cache_seq_next, + .stop = rt_cache_seq_stop, + .show = rt_cache_seq_show, +}; + +static int rt_cache_seq_open(struct inode *inode, struct file *file) +{ + return seq_open_net(inode, file, &rt_cache_seq_ops, + sizeof(struct rt_cache_iter_state)); +} + +static const struct file_operations rt_cache_seq_fops = { + .owner = THIS_MODULE, + .open = rt_cache_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net, +}; + + +static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) +{ + int cpu; + + if (*pos == 0) + return SEQ_START_TOKEN; + + for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { + if (!cpu_possible(cpu)) + continue; + *pos = cpu+1; + return &per_cpu(rt_cache_stat, cpu); + } + return NULL; +} + +static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + int cpu; + + for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { + if (!cpu_possible(cpu)) + continue; + *pos = cpu+1; + return &per_cpu(rt_cache_stat, cpu); + } + return NULL; + +} + +static void rt_cpu_seq_stop(struct seq_file *seq, void *v) +{ + +} + +static int rt_cpu_seq_show(struct seq_file *seq, void *v) +{ + struct rt_cache_stat *st = v; + + if (v == SEQ_START_TOKEN) { + seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n"); + return 0; + } + + seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " + " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", + dst_entries_get_slow(&ipv4_dst_ops), + st->in_hit, + st->in_slow_tot, + st->in_slow_mc, + st->in_no_route, + st->in_brd, + st->in_martian_dst, + st->in_martian_src, + + st->out_hit, + st->out_slow_tot, + st->out_slow_mc, + + st->gc_total, + st->gc_ignored, + st->gc_goal_miss, + st->gc_dst_overflow, + st->in_hlist_search, + st->out_hlist_search + ); + return 0; +} + +static const struct seq_operations rt_cpu_seq_ops = { + .start = rt_cpu_seq_start, + .next = rt_cpu_seq_next, + .stop = rt_cpu_seq_stop, + .show = rt_cpu_seq_show, +}; + + +static int rt_cpu_seq_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &rt_cpu_seq_ops); +} + +static const struct file_operations rt_cpu_seq_fops = { + .owner = THIS_MODULE, + .open = rt_cpu_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +#ifdef CONFIG_IP_ROUTE_CLASSID +static int rt_acct_proc_show(struct seq_file *m, void *v) +{ + struct ip_rt_acct *dst, *src; + unsigned int i, j; + + dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); + if (!dst) + return -ENOMEM; + + for_each_possible_cpu(i) { + src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); + for (j = 0; j < 256; j++) { + dst[j].o_bytes += src[j].o_bytes; + dst[j].o_packets += src[j].o_packets; + dst[j].i_bytes += src[j].i_bytes; + dst[j].i_packets += src[j].i_packets; + } + } + + seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); + kfree(dst); + return 0; +} + +static int rt_acct_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, rt_acct_proc_show, NULL); +} + +static const struct file_operations rt_acct_proc_fops = { + .owner = THIS_MODULE, + .open = rt_acct_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; +#endif + +static int __net_init ip_rt_do_proc_init(struct net *net) +{ + struct proc_dir_entry *pde; + + pde = proc_net_fops_create(net, "rt_cache", S_IRUGO, + &rt_cache_seq_fops); + if (!pde) + goto err1; + + pde = proc_create("rt_cache", S_IRUGO, + net->proc_net_stat, &rt_cpu_seq_fops); + if (!pde) + goto err2; + +#ifdef CONFIG_IP_ROUTE_CLASSID + pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops); + if (!pde) + goto err3; +#endif + return 0; + +#ifdef CONFIG_IP_ROUTE_CLASSID +err3: + remove_proc_entry("rt_cache", net->proc_net_stat); +#endif +err2: + remove_proc_entry("rt_cache", net->proc_net); +err1: + return -ENOMEM; +} + +static void __net_exit ip_rt_do_proc_exit(struct net *net) +{ + remove_proc_entry("rt_cache", net->proc_net_stat); + remove_proc_entry("rt_cache", net->proc_net); +#ifdef CONFIG_IP_ROUTE_CLASSID + remove_proc_entry("rt_acct", net->proc_net); +#endif +} + +static struct pernet_operations ip_rt_proc_ops __net_initdata = { + .init = ip_rt_do_proc_init, + .exit = ip_rt_do_proc_exit, +}; + +static int __init ip_rt_proc_init(void) +{ + return register_pernet_subsys(&ip_rt_proc_ops); +} + +#else +static inline int ip_rt_proc_init(void) +{ + return 0; +} +#endif /* CONFIG_PROC_FS */ + +static inline void rt_free(struct rtable *rt) +{ + call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free); +} + +static inline void rt_drop(struct rtable *rt) +{ + ip_rt_put(rt); + call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free); +} + +static inline int rt_fast_clean(struct rtable *rth) +{ + /* Kill broadcast/multicast entries very aggresively, if they + collide in hash table with more useful entries */ + return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) && + rt_is_input_route(rth) && rth->dst.rt_next; +} + +static inline int rt_valuable(struct rtable *rth) +{ + return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) || + (rth->peer && rth->peer->pmtu_expires); +} + +static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2) +{ + unsigned long age; + int ret = 0; + + if (atomic_read(&rth->dst.__refcnt)) + goto out; + + age = jiffies - rth->dst.lastuse; + if ((age <= tmo1 && !rt_fast_clean(rth)) || + (age <= tmo2 && rt_valuable(rth))) + goto out; + ret = 1; +out: return ret; +} + +/* Bits of score are: + * 31: very valuable + * 30: not quite useless + * 29..0: usage counter + */ +static inline u32 rt_score(struct rtable *rt) +{ + u32 score = jiffies - rt->dst.lastuse; + + score = ~score & ~(3<<30); + + if (rt_valuable(rt)) + score |= (1<<31); + + if (rt_is_output_route(rt) || + !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL))) + score |= (1<<30); + + return score; +} + +static inline bool rt_caching(const struct net *net) +{ + return net->ipv4.current_rt_cache_rebuild_count <= + net->ipv4.sysctl_rt_cache_rebuild_count; +} + +static inline bool compare_hash_inputs(const struct rtable *rt1, + const struct rtable *rt2) +{ + return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) | + ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) | + (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0); +} + +static inline int compare_keys(struct rtable *rt1, struct rtable *rt2) +{ + return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) | + ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) | + (rt1->rt_mark ^ rt2->rt_mark) | + (rt1->rt_key_tos ^ rt2->rt_key_tos) | + (rt1->rt_route_iif ^ rt2->rt_route_iif) | + (rt1->rt_oif ^ rt2->rt_oif)) == 0; +} + +static inline int compare_netns(struct rtable *rt1, struct rtable *rt2) +{ + return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev)); +} + +static inline int rt_is_expired(struct rtable *rth) +{ + return rth->rt_genid != rt_genid(dev_net(rth->dst.dev)); +} + +/* + * Perform a full scan of hash table and free all entries. + * Can be called by a softirq or a process. + * In the later case, we want to be reschedule if necessary + */ +static void rt_do_flush(struct net *net, int process_context) +{ + unsigned int i; + struct rtable *rth, *next; + + for (i = 0; i <= rt_hash_mask; i++) { + struct rtable __rcu **pprev; + struct rtable *list; + + if (process_context && need_resched()) + cond_resched(); + rth = rcu_access_pointer(rt_hash_table[i].chain); + if (!rth) + continue; + + spin_lock_bh(rt_hash_lock_addr(i)); + + list = NULL; + pprev = &rt_hash_table[i].chain; + rth = rcu_dereference_protected(*pprev, + lockdep_is_held(rt_hash_lock_addr(i))); + + while (rth) { + next = rcu_dereference_protected(rth->dst.rt_next, + lockdep_is_held(rt_hash_lock_addr(i))); + + if (!net || + net_eq(dev_net(rth->dst.dev), net)) { + rcu_assign_pointer(*pprev, next); + rcu_assign_pointer(rth->dst.rt_next, list); + list = rth; + } else { + pprev = &rth->dst.rt_next; + } + rth = next; + } + + spin_unlock_bh(rt_hash_lock_addr(i)); + + for (; list; list = next) { + next = rcu_dereference_protected(list->dst.rt_next, 1); + rt_free(list); + } + } +} + +/* + * While freeing expired entries, we compute average chain length + * and standard deviation, using fixed-point arithmetic. + * This to have an estimation of rt_chain_length_max + * rt_chain_length_max = max(elasticity, AVG + 4*SD) + * We use 3 bits for frational part, and 29 (or 61) for magnitude. + */ + +#define FRACT_BITS 3 +#define ONE (1UL << FRACT_BITS) + +/* + * Given a hash chain and an item in this hash chain, + * find if a previous entry has the same hash_inputs + * (but differs on tos, mark or oif) + * Returns 0 if an alias is found. + * Returns ONE if rth has no alias before itself. + */ +static int has_noalias(const struct rtable *head, const struct rtable *rth) +{ + const struct rtable *aux = head; + + while (aux != rth) { + if (compare_hash_inputs(aux, rth)) + return 0; + aux = rcu_dereference_protected(aux->dst.rt_next, 1); + } + return ONE; +} + +static void rt_check_expire(void) +{ + static unsigned int rover; + unsigned int i = rover, goal; + struct rtable *rth; + struct rtable __rcu **rthp; + unsigned long samples = 0; + unsigned long sum = 0, sum2 = 0; + unsigned long delta; + u64 mult; + + delta = jiffies - expires_ljiffies; + expires_ljiffies = jiffies; + mult = ((u64)delta) << rt_hash_log; + if (ip_rt_gc_timeout > 1) + do_div(mult, ip_rt_gc_timeout); + goal = (unsigned int)mult; + if (goal > rt_hash_mask) + goal = rt_hash_mask + 1; + for (; goal > 0; goal--) { + unsigned long tmo = ip_rt_gc_timeout; + unsigned long length; + + i = (i + 1) & rt_hash_mask; + rthp = &rt_hash_table[i].chain; + + if (need_resched()) + cond_resched(); + + samples++; + + if (rcu_dereference_raw(*rthp) == NULL) + continue; + length = 0; + spin_lock_bh(rt_hash_lock_addr(i)); + while ((rth = rcu_dereference_protected(*rthp, + lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) { + prefetch(rth->dst.rt_next); + if (rt_is_expired(rth)) { + *rthp = rth->dst.rt_next; + rt_free(rth); + continue; + } + if (rth->dst.expires) { + /* Entry is expired even if it is in use */ + if (time_before_eq(jiffies, rth->dst.expires)) { +nofree: + tmo >>= 1; + rthp = &rth->dst.rt_next; + /* + * We only count entries on + * a chain with equal hash inputs once + * so that entries for different QOS + * levels, and other non-hash input + * attributes don't unfairly skew + * the length computation + */ + length += has_noalias(rt_hash_table[i].chain, rth); + continue; + } + } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) + goto nofree; + + /* Cleanup aged off entries. */ + *rthp = rth->dst.rt_next; + rt_free(rth); + } + spin_unlock_bh(rt_hash_lock_addr(i)); + sum += length; + sum2 += length*length; + } + if (samples) { + unsigned long avg = sum / samples; + unsigned long sd = int_sqrt(sum2 / samples - avg*avg); + rt_chain_length_max = max_t(unsigned long, + ip_rt_gc_elasticity, + (avg + 4*sd) >> FRACT_BITS); + } + rover = i; +} + +/* + * rt_worker_func() is run in process context. + * we call rt_check_expire() to scan part of the hash table + */ +static void rt_worker_func(struct work_struct *work) +{ + rt_check_expire(); + schedule_delayed_work(&expires_work, ip_rt_gc_interval); +} + +/* + * Perturbation of rt_genid by a small quantity [1..256] + * Using 8 bits of shuffling ensure we can call rt_cache_invalidate() + * many times (2^24) without giving recent rt_genid. + * Jenkins hash is strong enough that litle changes of rt_genid are OK. + */ +static void rt_cache_invalidate(struct net *net) +{ + unsigned char shuffle; + + get_random_bytes(&shuffle, sizeof(shuffle)); + atomic_add(shuffle + 1U, &net->ipv4.rt_genid); + inetpeer_invalidate_tree(AF_INET); +} + +/* + * delay < 0 : invalidate cache (fast : entries will be deleted later) + * delay >= 0 : invalidate & flush cache (can be long) + */ +void rt_cache_flush(struct net *net, int delay) +{ + rt_cache_invalidate(net); + if (delay >= 0) + rt_do_flush(net, !in_softirq()); +} + +/* Flush previous cache invalidated entries from the cache */ +void rt_cache_flush_batch(struct net *net) +{ + rt_do_flush(net, !in_softirq()); +} + +static void rt_emergency_hash_rebuild(struct net *net) +{ + if (net_ratelimit()) + pr_warn("Route hash chain too long!\n"); + rt_cache_invalidate(net); +} + +/* + Short description of GC goals. + + We want to build algorithm, which will keep routing cache + at some equilibrium point, when number of aged off entries + is kept approximately equal to newly generated ones. + + Current expiration strength is variable "expire". + We try to adjust it dynamically, so that if networking + is idle expires is large enough to keep enough of warm entries, + and when load increases it reduces to limit cache size. + */ + +static int rt_garbage_collect(struct dst_ops *ops) +{ + static unsigned long expire = RT_GC_TIMEOUT; + static unsigned long last_gc; + static int rover; + static int equilibrium; + struct rtable *rth; + struct rtable __rcu **rthp; + unsigned long now = jiffies; + int goal; + int entries = dst_entries_get_fast(&ipv4_dst_ops); + + /* + * Garbage collection is pretty expensive, + * do not make it too frequently. + */ + + RT_CACHE_STAT_INC(gc_total); + + if (now - last_gc < ip_rt_gc_min_interval && + entries < ip_rt_max_size) { + RT_CACHE_STAT_INC(gc_ignored); + goto out; + } + + entries = dst_entries_get_slow(&ipv4_dst_ops); + /* Calculate number of entries, which we want to expire now. */ + goal = entries - (ip_rt_gc_elasticity << rt_hash_log); + if (goal <= 0) { + if (equilibrium < ipv4_dst_ops.gc_thresh) + equilibrium = ipv4_dst_ops.gc_thresh; + goal = entries - equilibrium; + if (goal > 0) { + equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1); + goal = entries - equilibrium; + } + } else { + /* We are in dangerous area. Try to reduce cache really + * aggressively. + */ + goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1); + equilibrium = entries - goal; + } + + if (now - last_gc >= ip_rt_gc_min_interval) + last_gc = now; + + if (goal <= 0) { + equilibrium += goal; + goto work_done; + } + + do { + int i, k; + + for (i = rt_hash_mask, k = rover; i >= 0; i--) { + unsigned long tmo = expire; + + k = (k + 1) & rt_hash_mask; + rthp = &rt_hash_table[k].chain; + spin_lock_bh(rt_hash_lock_addr(k)); + while ((rth = rcu_dereference_protected(*rthp, + lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) { + if (!rt_is_expired(rth) && + !rt_may_expire(rth, tmo, expire)) { + tmo >>= 1; + rthp = &rth->dst.rt_next; + continue; + } + *rthp = rth->dst.rt_next; + rt_free(rth); + goal--; + } + spin_unlock_bh(rt_hash_lock_addr(k)); + if (goal <= 0) + break; + } + rover = k; + + if (goal <= 0) + goto work_done; + + /* Goal is not achieved. We stop process if: + + - if expire reduced to zero. Otherwise, expire is halfed. + - if table is not full. + - if we are called from interrupt. + - jiffies check is just fallback/debug loop breaker. + We will not spin here for long time in any case. + */ + + RT_CACHE_STAT_INC(gc_goal_miss); + + if (expire == 0) + break; + + expire >>= 1; + + if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size) + goto out; + } while (!in_softirq() && time_before_eq(jiffies, now)); + + if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size) + goto out; + if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size) + goto out; + if (net_ratelimit()) + pr_warn("dst cache overflow\n"); + RT_CACHE_STAT_INC(gc_dst_overflow); + return 1; + +work_done: + expire += ip_rt_gc_min_interval; + if (expire > ip_rt_gc_timeout || + dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh || + dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh) + expire = ip_rt_gc_timeout; +out: return 0; +} + +/* + * Returns number of entries in a hash chain that have different hash_inputs + */ +static int slow_chain_length(const struct rtable *head) +{ + int length = 0; + const struct rtable *rth = head; + + while (rth) { + length += has_noalias(head, rth); + rth = rcu_dereference_protected(rth->dst.rt_next, 1); + } + return length >> FRACT_BITS; +} + +static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr) +{ + static const __be32 inaddr_any = 0; + struct net_device *dev = dst->dev; + const __be32 *pkey = daddr; + const struct rtable *rt; + struct neighbour *n; + + rt = (const struct rtable *) dst; + + if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + pkey = &inaddr_any; + else if (rt->rt_gateway) + pkey = (const __be32 *) &rt->rt_gateway; + + n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey); + if (n) + return n; + return neigh_create(&arp_tbl, pkey, dev); +} + +static int rt_bind_neighbour(struct rtable *rt) +{ + struct neighbour *n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway); + if (IS_ERR(n)) + return PTR_ERR(n); + dst_set_neighbour(&rt->dst, n); + + return 0; +} + +static struct rtable *rt_intern_hash(unsigned hash, struct rtable *rt, + struct sk_buff *skb, int ifindex) +{ + struct rtable *rth, *cand; + struct rtable __rcu **rthp, **candp; + unsigned long now; + u32 min_score; + int chain_length; + int attempts = !in_softirq(); + +restart: + chain_length = 0; + min_score = ~(u32)0; + cand = NULL; + candp = NULL; + now = jiffies; + + if (!rt_caching(dev_net(rt->dst.dev))) { + /* + * If we're not caching, just tell the caller we + * were successful and don't touch the route. The + * caller hold the sole reference to the cache entry, and + * it will be released when the caller is done with it. + * If we drop it here, the callers have no way to resolve routes + * when we're not caching. Instead, just point *rp at rt, so + * the caller gets a single use out of the route + * Note that we do rt_free on this new route entry, so that + * once its refcount hits zero, we are still able to reap it + * (Thanks Alexey) + * Note: To avoid expensive rcu stuff for this uncached dst, + * we set DST_NOCACHE so that dst_release() can free dst without + * waiting a grace period. + */ + + rt->dst.flags |= DST_NOCACHE; + if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) { + int err = rt_bind_neighbour(rt); + if (err) { + if (net_ratelimit()) + pr_warn("Neighbour table failure & not caching routes\n"); + ip_rt_put(rt); + return ERR_PTR(err); + } + } + + goto skip_hashing; + } + + rthp = &rt_hash_table[hash].chain; + + spin_lock_bh(rt_hash_lock_addr(hash)); + while ((rth = rcu_dereference_protected(*rthp, + lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) { + if (rt_is_expired(rth)) { + *rthp = rth->dst.rt_next; + rt_free(rth); + continue; + } + if (compare_keys(rth, rt) && compare_netns(rth, rt)) { + /* Put it first */ + *rthp = rth->dst.rt_next; + /* + * Since lookup is lockfree, the deletion + * must be visible to another weakly ordered CPU before + * the insertion at the start of the hash chain. + */ + rcu_assign_pointer(rth->dst.rt_next, + rt_hash_table[hash].chain); + /* + * Since lookup is lockfree, the update writes + * must be ordered for consistency on SMP. + */ + rcu_assign_pointer(rt_hash_table[hash].chain, rth); + + dst_use(&rth->dst, now); + spin_unlock_bh(rt_hash_lock_addr(hash)); + + rt_drop(rt); + if (skb) + skb_dst_set(skb, &rth->dst); + return rth; + } + + if (!atomic_read(&rth->dst.__refcnt)) { + u32 score = rt_score(rth); + + if (score <= min_score) { + cand = rth; + candp = rthp; + min_score = score; + } + } + + chain_length++; + + rthp = &rth->dst.rt_next; + } + + if (cand) { + /* ip_rt_gc_elasticity used to be average length of chain + * length, when exceeded gc becomes really aggressive. + * + * The second limit is less certain. At the moment it allows + * only 2 entries per bucket. We will see. + */ + if (chain_length > ip_rt_gc_elasticity) { + *candp = cand->dst.rt_next; + rt_free(cand); + } + } else { + if (chain_length > rt_chain_length_max && + slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) { + struct net *net = dev_net(rt->dst.dev); + int num = ++net->ipv4.current_rt_cache_rebuild_count; + if (!rt_caching(net)) { + pr_warn("%s: %d rebuilds is over limit, route caching disabled\n", + rt->dst.dev->name, num); + } + rt_emergency_hash_rebuild(net); + spin_unlock_bh(rt_hash_lock_addr(hash)); + + hash = rt_hash(rt->rt_key_dst, rt->rt_key_src, + ifindex, rt_genid(net)); + goto restart; + } + } + + /* Try to bind route to arp only if it is output + route or unicast forwarding path. + */ + if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) { + int err = rt_bind_neighbour(rt); + if (err) { + spin_unlock_bh(rt_hash_lock_addr(hash)); + + if (err != -ENOBUFS) { + rt_drop(rt); + return ERR_PTR(err); + } + + /* Neighbour tables are full and nothing + can be released. Try to shrink route cache, + it is most likely it holds some neighbour records. + */ + if (attempts-- > 0) { + int saved_elasticity = ip_rt_gc_elasticity; + int saved_int = ip_rt_gc_min_interval; + ip_rt_gc_elasticity = 1; + ip_rt_gc_min_interval = 0; + rt_garbage_collect(&ipv4_dst_ops); + ip_rt_gc_min_interval = saved_int; + ip_rt_gc_elasticity = saved_elasticity; + goto restart; + } + + if (net_ratelimit()) + pr_warn("Neighbour table overflow\n"); + rt_drop(rt); + return ERR_PTR(-ENOBUFS); + } + } + + rt->dst.rt_next = rt_hash_table[hash].chain; + + /* + * Since lookup is lockfree, we must make sure + * previous writes to rt are committed to memory + * before making rt visible to other CPUS. + */ + rcu_assign_pointer(rt_hash_table[hash].chain, rt); + + spin_unlock_bh(rt_hash_lock_addr(hash)); + +skip_hashing: + if (skb) + skb_dst_set(skb, &rt->dst); + return rt; +} + +static atomic_t __rt_peer_genid = ATOMIC_INIT(0); + +static u32 rt_peer_genid(void) +{ + return atomic_read(&__rt_peer_genid); +} + +void rt_bind_peer(struct rtable *rt, __be32 daddr, int create) +{ + struct inet_peer *peer; + + peer = inet_getpeer_v4(daddr, create); + + if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL) + inet_putpeer(peer); + else + rt->rt_peer_genid = rt_peer_genid(); +} + +/* + * Peer allocation may fail only in serious out-of-memory conditions. However + * we still can generate some output. + * Random ID selection looks a bit dangerous because we have no chances to + * select ID being unique in a reasonable period of time. + * But broken packet identifier may be better than no packet at all. + */ +static void ip_select_fb_ident(struct iphdr *iph) +{ + static DEFINE_SPINLOCK(ip_fb_id_lock); + static u32 ip_fallback_id; + u32 salt; + + spin_lock_bh(&ip_fb_id_lock); + salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr); + iph->id = htons(salt & 0xFFFF); + ip_fallback_id = salt; + spin_unlock_bh(&ip_fb_id_lock); +} + +void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more) +{ + struct rtable *rt = (struct rtable *) dst; + + if (rt && !(rt->dst.flags & DST_NOPEER)) { + if (rt->peer == NULL) + rt_bind_peer(rt, rt->rt_dst, 1); + + /* If peer is attached to destination, it is never detached, + so that we need not to grab a lock to dereference it. + */ + if (rt->peer) { + iph->id = htons(inet_getid(rt->peer, more)); + return; + } + } else if (!rt) + printk(KERN_DEBUG "rt_bind_peer(0) @%p\n", + __builtin_return_address(0)); + + ip_select_fb_ident(iph); +} +EXPORT_SYMBOL(__ip_select_ident); + +static void rt_del(unsigned hash, struct rtable *rt) +{ + struct rtable __rcu **rthp; + struct rtable *aux; + + rthp = &rt_hash_table[hash].chain; + spin_lock_bh(rt_hash_lock_addr(hash)); + ip_rt_put(rt); + while ((aux = rcu_dereference_protected(*rthp, + lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) { + if (aux == rt || rt_is_expired(aux)) { + *rthp = aux->dst.rt_next; + rt_free(aux); + continue; + } + rthp = &aux->dst.rt_next; + } + spin_unlock_bh(rt_hash_lock_addr(hash)); +} + +static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer) +{ + struct rtable *rt = (struct rtable *) dst; + __be32 orig_gw = rt->rt_gateway; + struct neighbour *n, *old_n; + + dst_confirm(&rt->dst); + + rt->rt_gateway = peer->redirect_learned.a4; + + n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway); + if (IS_ERR(n)) { + rt->rt_gateway = orig_gw; + return; + } + old_n = xchg(&rt->dst._neighbour, n); + if (old_n) + neigh_release(old_n); + if (!(n->nud_state & NUD_VALID)) { + neigh_event_send(n, NULL); + } else { + rt->rt_flags |= RTCF_REDIRECTED; + call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); + } +} + +/* called in rcu_read_lock() section */ +void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, + __be32 saddr, struct net_device *dev) +{ + int s, i; + struct in_device *in_dev = __in_dev_get_rcu(dev); + __be32 skeys[2] = { saddr, 0 }; + int ikeys[2] = { dev->ifindex, 0 }; + struct inet_peer *peer; + struct net *net; + + if (!in_dev) + return; + + net = dev_net(dev); + if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || + ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || + ipv4_is_zeronet(new_gw)) + goto reject_redirect; + + if (!IN_DEV_SHARED_MEDIA(in_dev)) { + if (!inet_addr_onlink(in_dev, new_gw, old_gw)) + goto reject_redirect; + if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) + goto reject_redirect; + } else { + if (inet_addr_type(net, new_gw) != RTN_UNICAST) + goto reject_redirect; + } + + for (s = 0; s < 2; s++) { + for (i = 0; i < 2; i++) { + unsigned int hash; + struct rtable __rcu **rthp; + struct rtable *rt; + + hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net)); + + rthp = &rt_hash_table[hash].chain; + + while ((rt = rcu_dereference(*rthp)) != NULL) { + rthp = &rt->dst.rt_next; + + if (rt->rt_key_dst != daddr || + rt->rt_key_src != skeys[s] || + rt->rt_oif != ikeys[i] || + rt_is_input_route(rt) || + rt_is_expired(rt) || + !net_eq(dev_net(rt->dst.dev), net) || + rt->dst.error || + rt->dst.dev != dev || + rt->rt_gateway != old_gw) + continue; + + if (!rt->peer) + rt_bind_peer(rt, rt->rt_dst, 1); + + peer = rt->peer; + if (peer) { + if (peer->redirect_learned.a4 != new_gw) { + peer->redirect_learned.a4 = new_gw; + atomic_inc(&__rt_peer_genid); + } + check_peer_redir(&rt->dst, peer); + } + } + } + } + return; + +reject_redirect: +#ifdef CONFIG_IP_ROUTE_VERBOSE + if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) + pr_info("Redirect from %pI4 on %s about %pI4 ignored\n" + " Advised path = %pI4 -> %pI4\n", + &old_gw, dev->name, &new_gw, + &saddr, &daddr); +#endif + ; +} + +static bool peer_pmtu_expired(struct inet_peer *peer) +{ + unsigned long orig = ACCESS_ONCE(peer->pmtu_expires); + + return orig && + time_after_eq(jiffies, orig) && + cmpxchg(&peer->pmtu_expires, orig, 0) == orig; +} + +static bool peer_pmtu_cleaned(struct inet_peer *peer) +{ + unsigned long orig = ACCESS_ONCE(peer->pmtu_expires); + + return orig && + cmpxchg(&peer->pmtu_expires, orig, 0) == orig; +} + +static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) +{ + struct rtable *rt = (struct rtable *)dst; + struct dst_entry *ret = dst; + + if (rt) { + if (dst->obsolete > 0) { + ip_rt_put(rt); + ret = NULL; + } else if (rt->rt_flags & RTCF_REDIRECTED) { + unsigned hash = rt_hash(rt->rt_key_dst, rt->rt_key_src, + rt->rt_oif, + rt_genid(dev_net(dst->dev))); + rt_del(hash, rt); + ret = NULL; + } else if (rt->peer && peer_pmtu_expired(rt->peer)) { + dst_metric_set(dst, RTAX_MTU, rt->peer->pmtu_orig); + } + } + return ret; +} + +/* + * Algorithm: + * 1. The first ip_rt_redirect_number redirects are sent + * with exponential backoff, then we stop sending them at all, + * assuming that the host ignores our redirects. + * 2. If we did not see packets requiring redirects + * during ip_rt_redirect_silence, we assume that the host + * forgot redirected route and start to send redirects again. + * + * This algorithm is much cheaper and more intelligent than dumb load limiting + * in icmp.c. + * + * NOTE. Do not forget to inhibit load limiting for redirects (redundant) + * and "frag. need" (breaks PMTU discovery) in icmp.c. + */ + +void ip_rt_send_redirect(struct sk_buff *skb) +{ + struct rtable *rt = skb_rtable(skb); + struct in_device *in_dev; + struct inet_peer *peer; + int log_martians; + + rcu_read_lock(); + in_dev = __in_dev_get_rcu(rt->dst.dev); + if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { + rcu_read_unlock(); + return; + } + log_martians = IN_DEV_LOG_MARTIANS(in_dev); + rcu_read_unlock(); + + if (!rt->peer) + rt_bind_peer(rt, rt->rt_dst, 1); + peer = rt->peer; + if (!peer) { + icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); + return; + } + + /* No redirected packets during ip_rt_redirect_silence; + * reset the algorithm. + */ + if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) + peer->rate_tokens = 0; + + /* Too many ignored redirects; do not send anything + * set dst.rate_last to the last seen redirected packet. + */ + if (peer->rate_tokens >= ip_rt_redirect_number) { + peer->rate_last = jiffies; + return; + } + + /* Check for load limit; set rate_last to the latest sent + * redirect. + */ + if (peer->rate_tokens == 0 || + time_after(jiffies, + (peer->rate_last + + (ip_rt_redirect_load << peer->rate_tokens)))) { + icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); + peer->rate_last = jiffies; + ++peer->rate_tokens; +#ifdef CONFIG_IP_ROUTE_VERBOSE + if (log_martians && + peer->rate_tokens == ip_rt_redirect_number && + net_ratelimit()) + pr_warn("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", + &ip_hdr(skb)->saddr, rt->rt_iif, + &rt->rt_dst, &rt->rt_gateway); +#endif + } +} + +static int ip_error(struct sk_buff *skb) +{ + struct rtable *rt = skb_rtable(skb); + struct inet_peer *peer; + unsigned long now; + bool send; + int code; + + switch (rt->dst.error) { + case EINVAL: + default: + goto out; + case EHOSTUNREACH: + code = ICMP_HOST_UNREACH; + break; + case ENETUNREACH: + code = ICMP_NET_UNREACH; + IP_INC_STATS_BH(dev_net(rt->dst.dev), + IPSTATS_MIB_INNOROUTES); + break; + case EACCES: + code = ICMP_PKT_FILTERED; + break; + } + + if (!rt->peer) + rt_bind_peer(rt, rt->rt_dst, 1); + peer = rt->peer; + + send = true; + if (peer) { + now = jiffies; + peer->rate_tokens += now - peer->rate_last; + if (peer->rate_tokens > ip_rt_error_burst) + peer->rate_tokens = ip_rt_error_burst; + peer->rate_last = now; + if (peer->rate_tokens >= ip_rt_error_cost) + peer->rate_tokens -= ip_rt_error_cost; + else + send = false; + } + if (send) + icmp_send(skb, ICMP_DEST_UNREACH, code, 0); + +out: kfree_skb(skb); + return 0; +} + +/* + * The last two values are not from the RFC but + * are needed for AMPRnet AX.25 paths. + */ + +static const unsigned short mtu_plateau[] = +{32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 }; + +static inline unsigned short guess_mtu(unsigned short old_mtu) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++) + if (old_mtu > mtu_plateau[i]) + return mtu_plateau[i]; + return 68; +} + +unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph, + unsigned short new_mtu, + struct net_device *dev) +{ + unsigned short old_mtu = ntohs(iph->tot_len); + unsigned short est_mtu = 0; + struct inet_peer *peer; + + peer = inet_getpeer_v4(iph->daddr, 1); + if (peer) { + unsigned short mtu = new_mtu; + + if (new_mtu < 68 || new_mtu >= old_mtu) { + /* BSD 4.2 derived systems incorrectly adjust + * tot_len by the IP header length, and report + * a zero MTU in the ICMP message. + */ + if (mtu == 0 && + old_mtu >= 68 + (iph->ihl << 2)) + old_mtu -= iph->ihl << 2; + mtu = guess_mtu(old_mtu); + } + + if (mtu < ip_rt_min_pmtu) + mtu = ip_rt_min_pmtu; + if (!peer->pmtu_expires || mtu < peer->pmtu_learned) { + unsigned long pmtu_expires; + + pmtu_expires = jiffies + ip_rt_mtu_expires; + if (!pmtu_expires) + pmtu_expires = 1UL; + + est_mtu = mtu; + peer->pmtu_learned = mtu; + peer->pmtu_expires = pmtu_expires; + atomic_inc(&__rt_peer_genid); + } + + inet_putpeer(peer); + } + return est_mtu ? : new_mtu; +} + +static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer) +{ + unsigned long expires = ACCESS_ONCE(peer->pmtu_expires); + + if (!expires) + return; + if (time_before(jiffies, expires)) { + u32 orig_dst_mtu = dst_mtu(dst); + if (peer->pmtu_learned < orig_dst_mtu) { + if (!peer->pmtu_orig) + peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU); + dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned); + } + } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires) + dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig); +} + +static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu) +{ + struct rtable *rt = (struct rtable *) dst; + struct inet_peer *peer; + + dst_confirm(dst); + + if (!rt->peer) + rt_bind_peer(rt, rt->rt_dst, 1); + peer = rt->peer; + if (peer) { + unsigned long pmtu_expires = ACCESS_ONCE(peer->pmtu_expires); + + if (mtu < ip_rt_min_pmtu) + mtu = ip_rt_min_pmtu; + if (!pmtu_expires || mtu < peer->pmtu_learned) { + + pmtu_expires = jiffies + ip_rt_mtu_expires; + if (!pmtu_expires) + pmtu_expires = 1UL; + + peer->pmtu_learned = mtu; + peer->pmtu_expires = pmtu_expires; + + atomic_inc(&__rt_peer_genid); + rt->rt_peer_genid = rt_peer_genid(); + } + check_peer_pmtu(dst, peer); + } +} + + +static void ipv4_validate_peer(struct rtable *rt) +{ + if (rt->rt_peer_genid != rt_peer_genid()) { + struct inet_peer *peer; + + if (!rt->peer) + rt_bind_peer(rt, rt->rt_dst, 0); + + peer = rt->peer; + if (peer) { + check_peer_pmtu(&rt->dst, peer); + + if (peer->redirect_learned.a4 && + peer->redirect_learned.a4 != rt->rt_gateway) + check_peer_redir(&rt->dst, peer); + } + + rt->rt_peer_genid = rt_peer_genid(); + } +} + +static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) +{ + struct rtable *rt = (struct rtable *) dst; + + if (rt_is_expired(rt)) + return NULL; + ipv4_validate_peer(rt); + return dst; +} + +static void ipv4_dst_destroy(struct dst_entry *dst) +{ + struct rtable *rt = (struct rtable *) dst; + struct inet_peer *peer = rt->peer; + + if (rt->fi) { + fib_info_put(rt->fi); + rt->fi = NULL; + } + if (peer) { + rt->peer = NULL; + inet_putpeer(peer); + } +} + + +static void ipv4_link_failure(struct sk_buff *skb) +{ + struct rtable *rt; + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); + + rt = skb_rtable(skb); + if (rt && rt->peer && peer_pmtu_cleaned(rt->peer)) + dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig); +} + +static int ip_rt_bug(struct sk_buff *skb) +{ + printk(KERN_DEBUG "ip_rt_bug: %pI4 -> %pI4, %s\n", + &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, + skb->dev ? skb->dev->name : "?"); + kfree_skb(skb); + WARN_ON(1); + return 0; +} + +/* + We do not cache source address of outgoing interface, + because it is used only by IP RR, TS and SRR options, + so that it out of fast path. + + BTW remember: "addr" is allowed to be not aligned + in IP options! + */ + +void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) +{ + __be32 src; + + if (rt_is_output_route(rt)) + src = ip_hdr(skb)->saddr; + else { + struct fib_result res; + struct flowi4 fl4; + struct iphdr *iph; + + iph = ip_hdr(skb); + + memset(&fl4, 0, sizeof(fl4)); + fl4.daddr = iph->daddr; + fl4.saddr = iph->saddr; + fl4.flowi4_tos = RT_TOS(iph->tos); + fl4.flowi4_oif = rt->dst.dev->ifindex; + fl4.flowi4_iif = skb->dev->ifindex; + fl4.flowi4_mark = skb->mark; + + rcu_read_lock(); + if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0) + src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); + else + src = inet_select_addr(rt->dst.dev, rt->rt_gateway, + RT_SCOPE_UNIVERSE); + rcu_read_unlock(); + } + memcpy(addr, &src, 4); +} + +#ifdef CONFIG_IP_ROUTE_CLASSID +static void set_class_tag(struct rtable *rt, u32 tag) +{ + if (!(rt->dst.tclassid & 0xFFFF)) + rt->dst.tclassid |= tag & 0xFFFF; + if (!(rt->dst.tclassid & 0xFFFF0000)) + rt->dst.tclassid |= tag & 0xFFFF0000; +} +#endif + +static unsigned int ipv4_default_advmss(const struct dst_entry *dst) +{ + unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS); + + if (advmss == 0) { + advmss = max_t(unsigned int, dst->dev->mtu - 40, + ip_rt_min_advmss); + if (advmss > 65535 - 40) + advmss = 65535 - 40; + } + return advmss; +} + +static unsigned int ipv4_mtu(const struct dst_entry *dst) +{ + const struct rtable *rt = (const struct rtable *) dst; + unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); + + if (mtu && rt_is_output_route(rt)) + return mtu; + + mtu = dst->dev->mtu; + + if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { + + if (rt->rt_gateway != rt->rt_dst && mtu > 576) + mtu = 576; + } + + if (mtu > IP_MAX_MTU) + mtu = IP_MAX_MTU; + + return mtu; +} + +static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4, + struct fib_info *fi) +{ + struct inet_peer *peer; + int create = 0; + + /* If a peer entry exists for this destination, we must hook + * it up in order to get at cached metrics. + */ + if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS)) + create = 1; + + rt->peer = peer = inet_getpeer_v4(rt->rt_dst, create); + if (peer) { + rt->rt_peer_genid = rt_peer_genid(); + if (inet_metrics_new(peer)) + memcpy(peer->metrics, fi->fib_metrics, + sizeof(u32) * RTAX_MAX); + dst_init_metrics(&rt->dst, peer->metrics, false); + + check_peer_pmtu(&rt->dst, peer); + + if (peer->redirect_learned.a4 && + peer->redirect_learned.a4 != rt->rt_gateway) { + rt->rt_gateway = peer->redirect_learned.a4; + rt->rt_flags |= RTCF_REDIRECTED; + } + } else { + if (fi->fib_metrics != (u32 *) dst_default_metrics) { + rt->fi = fi; + atomic_inc(&fi->fib_clntref); + } + dst_init_metrics(&rt->dst, fi->fib_metrics, true); + } +} + +static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4, + const struct fib_result *res, + struct fib_info *fi, u16 type, u32 itag) +{ + struct dst_entry *dst = &rt->dst; + + if (fi) { + if (FIB_RES_GW(*res) && + FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) + rt->rt_gateway = FIB_RES_GW(*res); + rt_init_metrics(rt, fl4, fi); +#ifdef CONFIG_IP_ROUTE_CLASSID + dst->tclassid = FIB_RES_NH(*res).nh_tclassid; +#endif + } + + if (dst_mtu(dst) > IP_MAX_MTU) + dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU); + if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40) + dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40); + +#ifdef CONFIG_IP_ROUTE_CLASSID +#ifdef CONFIG_IP_MULTIPLE_TABLES + set_class_tag(rt, fib_rules_tclass(res)); +#endif + set_class_tag(rt, itag); +#endif +} + +static struct rtable *rt_dst_alloc(struct net_device *dev, + bool nopolicy, bool noxfrm) +{ + return dst_alloc(&ipv4_dst_ops, dev, 1, -1, + DST_HOST | + (nopolicy ? DST_NOPOLICY : 0) | + (noxfrm ? DST_NOXFRM : 0)); +} + +/* called in rcu_read_lock() section */ +static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, + u8 tos, struct net_device *dev, int our) +{ + unsigned int hash; + struct rtable *rth; + __be32 spec_dst; + struct in_device *in_dev = __in_dev_get_rcu(dev); + u32 itag = 0; + int err; + + /* Primary sanity checks. */ + + if (in_dev == NULL) + return -EINVAL; + + if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || + ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP)) + goto e_inval; + + if (ipv4_is_zeronet(saddr)) { + if (!ipv4_is_local_multicast(daddr)) + goto e_inval; + spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK); + } else { + err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst, + &itag); + if (err < 0) + goto e_err; + } + rth = rt_dst_alloc(dev_net(dev)->loopback_dev, + IN_DEV_CONF_GET(in_dev, NOPOLICY), false); + if (!rth) + goto e_nobufs; + +#ifdef CONFIG_IP_ROUTE_CLASSID + rth->dst.tclassid = itag; +#endif + rth->dst.output = ip_rt_bug; + + rth->rt_key_dst = daddr; + rth->rt_key_src = saddr; + rth->rt_genid = rt_genid(dev_net(dev)); + rth->rt_flags = RTCF_MULTICAST; + rth->rt_type = RTN_MULTICAST; + rth->rt_key_tos = tos; + rth->rt_dst = daddr; + rth->rt_src = saddr; + rth->rt_route_iif = dev->ifindex; + rth->rt_iif = dev->ifindex; + rth->rt_oif = 0; + rth->rt_mark = skb->mark; + rth->rt_gateway = daddr; + rth->rt_spec_dst= spec_dst; + rth->rt_peer_genid = 0; + rth->peer = NULL; + rth->fi = NULL; + if (our) { + rth->dst.input= ip_local_deliver; + rth->rt_flags |= RTCF_LOCAL; + } + +#ifdef CONFIG_IP_MROUTE + if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) + rth->dst.input = ip_mr_input; +#endif + RT_CACHE_STAT_INC(in_slow_mc); + + hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev))); + rth = rt_intern_hash(hash, rth, skb, dev->ifindex); + return IS_ERR(rth) ? PTR_ERR(rth) : 0; + +e_nobufs: + return -ENOBUFS; +e_inval: + return -EINVAL; +e_err: + return err; +} + + +static void ip_handle_martian_source(struct net_device *dev, + struct in_device *in_dev, + struct sk_buff *skb, + __be32 daddr, + __be32 saddr) +{ + RT_CACHE_STAT_INC(in_martian_src); +#ifdef CONFIG_IP_ROUTE_VERBOSE + if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { + /* + * RFC1812 recommendation, if source is martian, + * the only hint is MAC header. + */ + pr_warn("martian source %pI4 from %pI4, on dev %s\n", + &daddr, &saddr, dev->name); + if (dev->hard_header_len && skb_mac_header_was_set(skb)) { + print_hex_dump(KERN_WARNING, "ll header: ", + DUMP_PREFIX_OFFSET, 16, 1, + skb_mac_header(skb), + dev->hard_header_len, true); + } + } +#endif +} + +/* called in rcu_read_lock() section */ +static int __mkroute_input(struct sk_buff *skb, + const struct fib_result *res, + struct in_device *in_dev, + __be32 daddr, __be32 saddr, u32 tos, + struct rtable **result) +{ + struct rtable *rth; + int err; + struct in_device *out_dev; + unsigned int flags = 0; + __be32 spec_dst; + u32 itag; + + /* get a working reference to the output device */ + out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); + if (out_dev == NULL) { + if (net_ratelimit()) + pr_crit("Bug in ip_route_input_slow(). Please report.\n"); + return -EINVAL; + } + + + err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), + in_dev->dev, &spec_dst, &itag); + if (err < 0) { + ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, + saddr); + + goto cleanup; + } + + if (err) + flags |= RTCF_DIRECTSRC; + + if (out_dev == in_dev && err && + (IN_DEV_SHARED_MEDIA(out_dev) || + inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) + flags |= RTCF_DOREDIRECT; + + if (skb->protocol != htons(ETH_P_IP)) { + /* Not IP (i.e. ARP). Do not create route, if it is + * invalid for proxy arp. DNAT routes are always valid. + * + * Proxy arp feature have been extended to allow, ARP + * replies back to the same interface, to support + * Private VLAN switch technologies. See arp.c. + */ + if (out_dev == in_dev && + IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { + err = -EINVAL; + goto cleanup; + } + } + + rth = rt_dst_alloc(out_dev->dev, + IN_DEV_CONF_GET(in_dev, NOPOLICY), + IN_DEV_CONF_GET(out_dev, NOXFRM)); + if (!rth) { + err = -ENOBUFS; + goto cleanup; + } + + rth->rt_key_dst = daddr; + rth->rt_key_src = saddr; + rth->rt_genid = rt_genid(dev_net(rth->dst.dev)); + rth->rt_flags = flags; + rth->rt_type = res->type; + rth->rt_key_tos = tos; + rth->rt_dst = daddr; + rth->rt_src = saddr; + rth->rt_route_iif = in_dev->dev->ifindex; + rth->rt_iif = in_dev->dev->ifindex; + rth->rt_oif = 0; + rth->rt_mark = skb->mark; + rth->rt_gateway = daddr; + rth->rt_spec_dst= spec_dst; + rth->rt_peer_genid = 0; + rth->peer = NULL; + rth->fi = NULL; + + rth->dst.input = ip_forward; + rth->dst.output = ip_output; + + rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag); + + *result = rth; + err = 0; + cleanup: + return err; +} + +static int ip_mkroute_input(struct sk_buff *skb, + struct fib_result *res, + const struct flowi4 *fl4, + struct in_device *in_dev, + __be32 daddr, __be32 saddr, u32 tos) +{ + struct rtable* rth = NULL; + int err; + unsigned hash; + +#ifdef CONFIG_IP_ROUTE_MULTIPATH + if (res->fi && res->fi->fib_nhs > 1) + fib_select_multipath(res); +#endif + + /* create a routing cache entry */ + err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth); + if (err) + return err; + + /* put it into the cache */ + hash = rt_hash(daddr, saddr, fl4->flowi4_iif, + rt_genid(dev_net(rth->dst.dev))); + rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif); + if (IS_ERR(rth)) + return PTR_ERR(rth); + return 0; +} + +/* + * NOTE. We drop all the packets that has local source + * addresses, because every properly looped back packet + * must have correct destination already attached by output routine. + * + * Such approach solves two big problems: + * 1. Not simplex devices are handled properly. + * 2. IP spoofing attempts are filtered with 100% of guarantee. + * called with rcu_read_lock() + */ + +static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, + u8 tos, struct net_device *dev) +{ + struct fib_result res; + struct in_device *in_dev = __in_dev_get_rcu(dev); + struct flowi4 fl4; + unsigned flags = 0; + u32 itag = 0; + struct rtable * rth; + unsigned hash; + __be32 spec_dst; + int err = -EINVAL; + struct net * net = dev_net(dev); + + /* IP on this device is disabled. */ + + if (!in_dev) + goto out; + + /* Check for the most weird martians, which can be not detected + by fib_lookup. + */ + + if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || + ipv4_is_loopback(saddr)) + goto martian_source; + + if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) + goto brd_input; + + /* Accept zero addresses only to limited broadcast; + * I even do not know to fix it or not. Waiting for complains :-) + */ + if (ipv4_is_zeronet(saddr)) + goto martian_source; + + if (ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr)) + goto martian_destination; + + /* + * Now we are ready to route packet. + */ + fl4.flowi4_oif = 0; + fl4.flowi4_iif = dev->ifindex; + fl4.flowi4_mark = skb->mark; + fl4.flowi4_tos = tos; + fl4.flowi4_scope = RT_SCOPE_UNIVERSE; + fl4.daddr = daddr; + fl4.saddr = saddr; + err = fib_lookup(net, &fl4, &res); + if (err != 0) { + if (!IN_DEV_FORWARD(in_dev)) + goto e_hostunreach; + goto no_route; + } + + RT_CACHE_STAT_INC(in_slow_tot); + + if (res.type == RTN_BROADCAST) + goto brd_input; + + if (res.type == RTN_LOCAL) { + err = fib_validate_source(skb, saddr, daddr, tos, + net->loopback_dev->ifindex, + dev, &spec_dst, &itag); + if (err < 0) + goto martian_source_keep_err; + if (err) + flags |= RTCF_DIRECTSRC; + spec_dst = daddr; + goto local_input; + } + + if (!IN_DEV_FORWARD(in_dev)) + goto e_hostunreach; + if (res.type != RTN_UNICAST) + goto martian_destination; + + err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos); +out: return err; + +brd_input: + if (skb->protocol != htons(ETH_P_IP)) + goto e_inval; + + if (ipv4_is_zeronet(saddr)) + spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK); + else { + err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst, + &itag); + if (err < 0) + goto martian_source_keep_err; + if (err) + flags |= RTCF_DIRECTSRC; + } + flags |= RTCF_BROADCAST; + res.type = RTN_BROADCAST; + RT_CACHE_STAT_INC(in_brd); + +local_input: + rth = rt_dst_alloc(net->loopback_dev, + IN_DEV_CONF_GET(in_dev, NOPOLICY), false); + if (!rth) + goto e_nobufs; + + rth->dst.input= ip_local_deliver; + rth->dst.output= ip_rt_bug; +#ifdef CONFIG_IP_ROUTE_CLASSID + rth->dst.tclassid = itag; +#endif + + rth->rt_key_dst = daddr; + rth->rt_key_src = saddr; + rth->rt_genid = rt_genid(net); + rth->rt_flags = flags|RTCF_LOCAL; + rth->rt_type = res.type; + rth->rt_key_tos = tos; + rth->rt_dst = daddr; + rth->rt_src = saddr; +#ifdef CONFIG_IP_ROUTE_CLASSID + rth->dst.tclassid = itag; +#endif + rth->rt_route_iif = dev->ifindex; + rth->rt_iif = dev->ifindex; + rth->rt_oif = 0; + rth->rt_mark = skb->mark; + rth->rt_gateway = daddr; + rth->rt_spec_dst= spec_dst; + rth->rt_peer_genid = 0; + rth->peer = NULL; + rth->fi = NULL; + if (res.type == RTN_UNREACHABLE) { + rth->dst.input= ip_error; + rth->dst.error= -err; + rth->rt_flags &= ~RTCF_LOCAL; + } + hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net)); + rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif); + err = 0; + if (IS_ERR(rth)) + err = PTR_ERR(rth); + goto out; + +no_route: + RT_CACHE_STAT_INC(in_no_route); + spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE); + res.type = RTN_UNREACHABLE; + if (err == -ESRCH) + err = -ENETUNREACH; + goto local_input; + + /* + * Do not cache martian addresses: they should be logged (RFC1812) + */ +martian_destination: + RT_CACHE_STAT_INC(in_martian_dst); +#ifdef CONFIG_IP_ROUTE_VERBOSE + if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) + pr_warn("martian destination %pI4 from %pI4, dev %s\n", + &daddr, &saddr, dev->name); +#endif + +e_hostunreach: + err = -EHOSTUNREACH; + goto out; + +e_inval: + err = -EINVAL; + goto out; + +e_nobufs: + err = -ENOBUFS; + goto out; + +martian_source: + err = -EINVAL; +martian_source_keep_err: + ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); + goto out; +} + +int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr, + u8 tos, struct net_device *dev, bool noref) +{ + struct rtable * rth; + unsigned hash; + int iif = dev->ifindex; + struct net *net; + int res; + + net = dev_net(dev); + + rcu_read_lock(); + + if (!rt_caching(net)) + goto skip_cache; + + tos &= IPTOS_RT_MASK; + hash = rt_hash(daddr, saddr, iif, rt_genid(net)); + + for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; + rth = rcu_dereference(rth->dst.rt_next)) { + if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) | + ((__force u32)rth->rt_key_src ^ (__force u32)saddr) | + (rth->rt_route_iif ^ iif) | + (rth->rt_key_tos ^ tos)) == 0 && + rth->rt_mark == skb->mark && + net_eq(dev_net(rth->dst.dev), net) && + !rt_is_expired(rth)) { + ipv4_validate_peer(rth); + if (noref) { + dst_use_noref(&rth->dst, jiffies); + skb_dst_set_noref(skb, &rth->dst); + } else { + dst_use(&rth->dst, jiffies); + skb_dst_set(skb, &rth->dst); + } + RT_CACHE_STAT_INC(in_hit); + rcu_read_unlock(); + return 0; + } + RT_CACHE_STAT_INC(in_hlist_search); + } + +skip_cache: + /* Multicast recognition logic is moved from route cache to here. + The problem was that too many Ethernet cards have broken/missing + hardware multicast filters :-( As result the host on multicasting + network acquires a lot of useless route cache entries, sort of + SDR messages from all the world. Now we try to get rid of them. + Really, provided software IP multicast filter is organized + reasonably (at least, hashed), it does not result in a slowdown + comparing with route cache reject entries. + Note, that multicast routers are not affected, because + route cache entry is created eventually. + */ + if (ipv4_is_multicast(daddr)) { + struct in_device *in_dev = __in_dev_get_rcu(dev); + + if (in_dev) { + int our = ip_check_mc_rcu(in_dev, daddr, saddr, + ip_hdr(skb)->protocol); + if (our +#ifdef CONFIG_IP_MROUTE + || + (!ipv4_is_local_multicast(daddr) && + IN_DEV_MFORWARD(in_dev)) +#endif + ) { + int res = ip_route_input_mc(skb, daddr, saddr, + tos, dev, our); + rcu_read_unlock(); + return res; + } + } + rcu_read_unlock(); + return -EINVAL; + } + res = ip_route_input_slow(skb, daddr, saddr, tos, dev); + rcu_read_unlock(); + return res; +} +EXPORT_SYMBOL(ip_route_input_common); + +/* called with rcu_read_lock() */ +static struct rtable *__mkroute_output(const struct fib_result *res, + const struct flowi4 *fl4, + __be32 orig_daddr, __be32 orig_saddr, + int orig_oif, __u8 orig_rtos, + struct net_device *dev_out, + unsigned int flags) +{ + struct fib_info *fi = res->fi; + struct in_device *in_dev; + u16 type = res->type; + struct rtable *rth; + + if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK)) + return ERR_PTR(-EINVAL); + + if (ipv4_is_lbcast(fl4->daddr)) + type = RTN_BROADCAST; + else if (ipv4_is_multicast(fl4->daddr)) + type = RTN_MULTICAST; + else if (ipv4_is_zeronet(fl4->daddr)) + return ERR_PTR(-EINVAL); + + if (dev_out->flags & IFF_LOOPBACK) + flags |= RTCF_LOCAL; + + in_dev = __in_dev_get_rcu(dev_out); + if (!in_dev) + return ERR_PTR(-EINVAL); + + if (type == RTN_BROADCAST) { + flags |= RTCF_BROADCAST | RTCF_LOCAL; + fi = NULL; + } else if (type == RTN_MULTICAST) { + flags |= RTCF_MULTICAST | RTCF_LOCAL; + if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, + fl4->flowi4_proto)) + flags &= ~RTCF_LOCAL; + /* If multicast route do not exist use + * default one, but do not gateway in this case. + * Yes, it is hack. + */ + if (fi && res->prefixlen < 4) + fi = NULL; + } + + rth = rt_dst_alloc(dev_out, + IN_DEV_CONF_GET(in_dev, NOPOLICY), + IN_DEV_CONF_GET(in_dev, NOXFRM)); + if (!rth) + return ERR_PTR(-ENOBUFS); + + rth->dst.output = ip_output; + + rth->rt_key_dst = orig_daddr; + rth->rt_key_src = orig_saddr; + rth->rt_genid = rt_genid(dev_net(dev_out)); + rth->rt_flags = flags; + rth->rt_type = type; + rth->rt_key_tos = orig_rtos; + rth->rt_dst = fl4->daddr; + rth->rt_src = fl4->saddr; + rth->rt_route_iif = 0; + rth->rt_iif = orig_oif ? : dev_out->ifindex; + rth->rt_oif = orig_oif; + rth->rt_mark = fl4->flowi4_mark; + rth->rt_gateway = fl4->daddr; + rth->rt_spec_dst= fl4->saddr; + rth->rt_peer_genid = 0; + rth->peer = NULL; + rth->fi = NULL; + + RT_CACHE_STAT_INC(out_slow_tot); + + if (flags & RTCF_LOCAL) { + rth->dst.input = ip_local_deliver; + rth->rt_spec_dst = fl4->daddr; + } + if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { + rth->rt_spec_dst = fl4->saddr; + if (flags & RTCF_LOCAL && + !(dev_out->flags & IFF_LOOPBACK)) { + rth->dst.output = ip_mc_output; + RT_CACHE_STAT_INC(out_slow_mc); + } +#ifdef CONFIG_IP_MROUTE + if (type == RTN_MULTICAST) { + if (IN_DEV_MFORWARD(in_dev) && + !ipv4_is_local_multicast(fl4->daddr)) { + rth->dst.input = ip_mr_input; + rth->dst.output = ip_mc_output; + } + } +#endif + } + + rt_set_nexthop(rth, fl4, res, fi, type, 0); + + return rth; +} + +/* + * Major route resolver routine. + * called with rcu_read_lock(); + */ + +static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4) +{ + struct net_device *dev_out = NULL; + __u8 tos = RT_FL_TOS(fl4); + unsigned int flags = 0; + struct fib_result res; + struct rtable *rth; + __be32 orig_daddr; + __be32 orig_saddr; + int orig_oif; + + res.fi = NULL; +#ifdef CONFIG_IP_MULTIPLE_TABLES + res.r = NULL; +#endif + + orig_daddr = fl4->daddr; + orig_saddr = fl4->saddr; + orig_oif = fl4->flowi4_oif; + + fl4->flowi4_iif = net->loopback_dev->ifindex; + fl4->flowi4_tos = tos & IPTOS_RT_MASK; + fl4->flowi4_scope = ((tos & RTO_ONLINK) ? + RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); + + rcu_read_lock(); + if (fl4->saddr) { + rth = ERR_PTR(-EINVAL); + if (ipv4_is_multicast(fl4->saddr) || + ipv4_is_lbcast(fl4->saddr) || + ipv4_is_zeronet(fl4->saddr)) + goto out; + + /* I removed check for oif == dev_out->oif here. + It was wrong for two reasons: + 1. ip_dev_find(net, saddr) can return wrong iface, if saddr + is assigned to multiple interfaces. + 2. Moreover, we are allowed to send packets with saddr + of another iface. --ANK + */ + + if (fl4->flowi4_oif == 0 && + (ipv4_is_multicast(fl4->daddr) || + ipv4_is_lbcast(fl4->daddr))) { + /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ + dev_out = __ip_dev_find(net, fl4->saddr, false); + if (dev_out == NULL) + goto out; + + /* Special hack: user can direct multicasts + and limited broadcast via necessary interface + without fiddling with IP_MULTICAST_IF or IP_PKTINFO. + This hack is not just for fun, it allows + vic,vat and friends to work. + They bind socket to loopback, set ttl to zero + and expect that it will work. + From the viewpoint of routing cache they are broken, + because we are not allowed to build multicast path + with loopback source addr (look, routing cache + cannot know, that ttl is zero, so that packet + will not leave this host and route is valid). + Luckily, this hack is good workaround. + */ + + fl4->flowi4_oif = dev_out->ifindex; + goto make_route; + } + + if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { + /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ + if (!__ip_dev_find(net, fl4->saddr, false)) + goto out; + } + } + + + if (fl4->flowi4_oif) { + dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); + rth = ERR_PTR(-ENODEV); + if (dev_out == NULL) + goto out; + + /* RACE: Check return value of inet_select_addr instead. */ + if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { + rth = ERR_PTR(-ENETUNREACH); + goto out; + } + if (ipv4_is_local_multicast(fl4->daddr) || + ipv4_is_lbcast(fl4->daddr)) { + if (!fl4->saddr) + fl4->saddr = inet_select_addr(dev_out, 0, + RT_SCOPE_LINK); + goto make_route; + } + if (fl4->saddr) { + if (ipv4_is_multicast(fl4->daddr)) + fl4->saddr = inet_select_addr(dev_out, 0, + fl4->flowi4_scope); + else if (!fl4->daddr) + fl4->saddr = inet_select_addr(dev_out, 0, + RT_SCOPE_HOST); + } + } + + if (!fl4->daddr) { + fl4->daddr = fl4->saddr; + if (!fl4->daddr) + fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); + dev_out = net->loopback_dev; + fl4->flowi4_oif = net->loopback_dev->ifindex; + res.type = RTN_LOCAL; + flags |= RTCF_LOCAL; + goto make_route; + } + + if (fib_lookup(net, fl4, &res)) { + res.fi = NULL; + if (fl4->flowi4_oif) { + /* Apparently, routing tables are wrong. Assume, + that the destination is on link. + + WHY? DW. + Because we are allowed to send to iface + even if it has NO routes and NO assigned + addresses. When oif is specified, routing + tables are looked up with only one purpose: + to catch if destination is gatewayed, rather than + direct. Moreover, if MSG_DONTROUTE is set, + we send packet, ignoring both routing tables + and ifaddr state. --ANK + + + We could make it even if oif is unknown, + likely IPv6, but we do not. + */ + + if (fl4->saddr == 0) + fl4->saddr = inet_select_addr(dev_out, 0, + RT_SCOPE_LINK); + res.type = RTN_UNICAST; + goto make_route; + } + rth = ERR_PTR(-ENETUNREACH); + goto out; + } + + if (res.type == RTN_LOCAL) { + if (!fl4->saddr) { + if (res.fi->fib_prefsrc) + fl4->saddr = res.fi->fib_prefsrc; + else + fl4->saddr = fl4->daddr; + } + dev_out = net->loopback_dev; + fl4->flowi4_oif = dev_out->ifindex; + res.fi = NULL; + flags |= RTCF_LOCAL; + goto make_route; + } + +#ifdef CONFIG_IP_ROUTE_MULTIPATH + if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0) + fib_select_multipath(&res); + else +#endif + if (!res.prefixlen && + res.table->tb_num_default > 1 && + res.type == RTN_UNICAST && !fl4->flowi4_oif) + fib_select_default(&res); + + if (!fl4->saddr) + fl4->saddr = FIB_RES_PREFSRC(net, res); + + dev_out = FIB_RES_DEV(res); + fl4->flowi4_oif = dev_out->ifindex; + + +make_route: + rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif, + tos, dev_out, flags); + if (!IS_ERR(rth)) { + unsigned int hash; + + hash = rt_hash(orig_daddr, orig_saddr, orig_oif, + rt_genid(dev_net(dev_out))); + rth = rt_intern_hash(hash, rth, NULL, orig_oif); + } + +out: + rcu_read_unlock(); + return rth; +} + +struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4) +{ + struct rtable *rth; + unsigned int hash; + + if (!rt_caching(net)) + goto slow_output; + + hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net)); + + rcu_read_lock_bh(); + for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth; + rth = rcu_dereference_bh(rth->dst.rt_next)) { + if (rth->rt_key_dst == flp4->daddr && + rth->rt_key_src == flp4->saddr && + rt_is_output_route(rth) && + rth->rt_oif == flp4->flowi4_oif && + rth->rt_mark == flp4->flowi4_mark && + !((rth->rt_key_tos ^ flp4->flowi4_tos) & + (IPTOS_RT_MASK | RTO_ONLINK)) && + net_eq(dev_net(rth->dst.dev), net) && + !rt_is_expired(rth)) { + ipv4_validate_peer(rth); + dst_use(&rth->dst, jiffies); + RT_CACHE_STAT_INC(out_hit); + rcu_read_unlock_bh(); + if (!flp4->saddr) + flp4->saddr = rth->rt_src; + if (!flp4->daddr) + flp4->daddr = rth->rt_dst; + return rth; + } + RT_CACHE_STAT_INC(out_hlist_search); + } + rcu_read_unlock_bh(); + +slow_output: + return ip_route_output_slow(net, flp4); +} +EXPORT_SYMBOL_GPL(__ip_route_output_key); + +static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) +{ + return NULL; +} + +static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) +{ + unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); + + return mtu ? : dst->dev->mtu; +} + +static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu) +{ +} + +static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, + unsigned long old) +{ + return NULL; +} + +static struct dst_ops ipv4_dst_blackhole_ops = { + .family = AF_INET, + .protocol = cpu_to_be16(ETH_P_IP), + .destroy = ipv4_dst_destroy, + .check = ipv4_blackhole_dst_check, + .mtu = ipv4_blackhole_mtu, + .default_advmss = ipv4_default_advmss, + .update_pmtu = ipv4_rt_blackhole_update_pmtu, + .cow_metrics = ipv4_rt_blackhole_cow_metrics, + .neigh_lookup = ipv4_neigh_lookup, +}; + +struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) +{ + struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0); + struct rtable *ort = (struct rtable *) dst_orig; + + if (rt) { + struct dst_entry *new = &rt->dst; + + new->__use = 1; + new->input = dst_discard; + new->output = dst_discard; + dst_copy_metrics(new, &ort->dst); + + new->dev = ort->dst.dev; + if (new->dev) + dev_hold(new->dev); + + rt->rt_key_dst = ort->rt_key_dst; + rt->rt_key_src = ort->rt_key_src; + rt->rt_key_tos = ort->rt_key_tos; + rt->rt_route_iif = ort->rt_route_iif; + rt->rt_iif = ort->rt_iif; + rt->rt_oif = ort->rt_oif; + rt->rt_mark = ort->rt_mark; + + rt->rt_genid = rt_genid(net); + rt->rt_flags = ort->rt_flags; + rt->rt_type = ort->rt_type; + rt->rt_dst = ort->rt_dst; + rt->rt_src = ort->rt_src; + rt->rt_gateway = ort->rt_gateway; + rt->rt_spec_dst = ort->rt_spec_dst; + rt->peer = ort->peer; + if (rt->peer) + atomic_inc(&rt->peer->refcnt); + rt->fi = ort->fi; + if (rt->fi) + atomic_inc(&rt->fi->fib_clntref); + + dst_free(new); + } + + dst_release(dst_orig); + + return rt ? &rt->dst : ERR_PTR(-ENOMEM); +} + +struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, + struct sock *sk) +{ + struct rtable *rt = __ip_route_output_key(net, flp4); + + if (IS_ERR(rt)) + return rt; + + if (flp4->flowi4_proto) + rt = (struct rtable *) xfrm_lookup(net, &rt->dst, + flowi4_to_flowi(flp4), + sk, 0); + + return rt; +} +EXPORT_SYMBOL_GPL(ip_route_output_flow); + +static int rt_fill_info(struct net *net, + struct sk_buff *skb, u32 pid, u32 seq, int event, + int nowait, unsigned int flags) +{ + struct rtable *rt = skb_rtable(skb); + struct rtmsg *r; + struct nlmsghdr *nlh; + unsigned long expires = 0; + const struct inet_peer *peer = rt->peer; + u32 id = 0, ts = 0, tsage = 0, error; + + nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags); + if (nlh == NULL) + return -EMSGSIZE; + + r = nlmsg_data(nlh); + r->rtm_family = AF_INET; + r->rtm_dst_len = 32; + r->rtm_src_len = 0; + r->rtm_tos = rt->rt_key_tos; + r->rtm_table = RT_TABLE_MAIN; + NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN); + r->rtm_type = rt->rt_type; + r->rtm_scope = RT_SCOPE_UNIVERSE; + r->rtm_protocol = RTPROT_UNSPEC; + r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; + if (rt->rt_flags & RTCF_NOTIFY) + r->rtm_flags |= RTM_F_NOTIFY; + + NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst); + + if (rt->rt_key_src) { + r->rtm_src_len = 32; + NLA_PUT_BE32(skb, RTA_SRC, rt->rt_key_src); + } + if (rt->dst.dev) + NLA_PUT_U32(skb, RTA_OIF, rt->dst.dev->ifindex); +#ifdef CONFIG_IP_ROUTE_CLASSID + if (rt->dst.tclassid) + NLA_PUT_U32(skb, RTA_FLOW, rt->dst.tclassid); +#endif + if (rt_is_input_route(rt)) + NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst); + else if (rt->rt_src != rt->rt_key_src) + NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src); + + if (rt->rt_dst != rt->rt_gateway) + NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway); + + if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0) + goto nla_put_failure; + + if (rt->rt_mark) + NLA_PUT_BE32(skb, RTA_MARK, rt->rt_mark); + + error = rt->dst.error; + if (peer) { + inet_peer_refcheck(rt->peer); + id = atomic_read(&peer->ip_id_count) & 0xffff; + if (peer->tcp_ts_stamp) { + ts = peer->tcp_ts; + tsage = get_seconds() - peer->tcp_ts_stamp; + } + expires = ACCESS_ONCE(peer->pmtu_expires); + if (expires) { + if (time_before(jiffies, expires)) + expires -= jiffies; + else + expires = 0; + } + } + + if (rt_is_input_route(rt)) { +#ifdef CONFIG_IP_MROUTE + __be32 dst = rt->rt_dst; + + if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && + IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { + int err = ipmr_get_route(net, skb, + rt->rt_src, rt->rt_dst, + r, nowait); + if (err <= 0) { + if (!nowait) { + if (err == 0) + return 0; + goto nla_put_failure; + } else { + if (err == -EMSGSIZE) + goto nla_put_failure; + error = err; + } + } + } else +#endif + NLA_PUT_U32(skb, RTA_IIF, rt->rt_iif); + } + + if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage, + expires, error) < 0) + goto nla_put_failure; + + return nlmsg_end(skb, nlh); + +nla_put_failure: + nlmsg_cancel(skb, nlh); + return -EMSGSIZE; +} + +static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg) +{ + struct net *net = sock_net(in_skb->sk); + struct rtmsg *rtm; + struct nlattr *tb[RTA_MAX+1]; + struct rtable *rt = NULL; + __be32 dst = 0; + __be32 src = 0; + u32 iif; + int err; + int mark; + struct sk_buff *skb; + + err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); + if (err < 0) + goto errout; + + rtm = nlmsg_data(nlh); + + skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); + if (skb == NULL) { + err = -ENOBUFS; + goto errout; + } + + /* Reserve room for dummy headers, this skb can pass + through good chunk of routing engine. + */ + skb_reset_mac_header(skb); + skb_reset_network_header(skb); + + /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ + ip_hdr(skb)->protocol = IPPROTO_ICMP; + skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); + + src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0; + dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0; + iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; + mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; + + if (iif) { + struct net_device *dev; + + dev = __dev_get_by_index(net, iif); + if (dev == NULL) { + err = -ENODEV; + goto errout_free; + } + + skb->protocol = htons(ETH_P_IP); + skb->dev = dev; + skb->mark = mark; + local_bh_disable(); + err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); + local_bh_enable(); + + rt = skb_rtable(skb); + if (err == 0 && rt->dst.error) + err = -rt->dst.error; + } else { + struct flowi4 fl4 = { + .daddr = dst, + .saddr = src, + .flowi4_tos = rtm->rtm_tos, + .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0, + .flowi4_mark = mark, + }; + rt = ip_route_output_key(net, &fl4); + + err = 0; + if (IS_ERR(rt)) + err = PTR_ERR(rt); + } + + if (err) + goto errout_free; + + skb_dst_set(skb, &rt->dst); + if (rtm->rtm_flags & RTM_F_NOTIFY) + rt->rt_flags |= RTCF_NOTIFY; + + err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, + RTM_NEWROUTE, 0, 0); + if (err <= 0) + goto errout_free; + + err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid); +errout: + return err; + +errout_free: + kfree_skb(skb); + goto errout; +} + +int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct rtable *rt; + int h, s_h; + int idx, s_idx; + struct net *net; + + net = sock_net(skb->sk); + + s_h = cb->args[0]; + if (s_h < 0) + s_h = 0; + s_idx = idx = cb->args[1]; + for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) { + if (!rt_hash_table[h].chain) + continue; + rcu_read_lock_bh(); + for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt; + rt = rcu_dereference_bh(rt->dst.rt_next), idx++) { + if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx) + continue; + if (rt_is_expired(rt)) + continue; + skb_dst_set_noref(skb, &rt->dst); + if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid, + cb->nlh->nlmsg_seq, RTM_NEWROUTE, + 1, NLM_F_MULTI) <= 0) { + skb_dst_drop(skb); + rcu_read_unlock_bh(); + goto done; + } + skb_dst_drop(skb); + } + rcu_read_unlock_bh(); + } + +done: + cb->args[0] = h; + cb->args[1] = idx; + return skb->len; +} + +void ip_rt_multicast_event(struct in_device *in_dev) +{ + rt_cache_flush(dev_net(in_dev->dev), 0); +} + +#ifdef CONFIG_SYSCTL +static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write, + void __user *buffer, + size_t *lenp, loff_t *ppos) +{ + if (write) { + int flush_delay; + ctl_table ctl; + struct net *net; + + memcpy(&ctl, __ctl, sizeof(ctl)); + ctl.data = &flush_delay; + proc_dointvec(&ctl, write, buffer, lenp, ppos); + + net = (struct net *)__ctl->extra1; + rt_cache_flush(net, flush_delay); + return 0; + } + + return -EINVAL; +} + +static ctl_table ipv4_route_table[] = { + { + .procname = "gc_thresh", + .data = &ipv4_dst_ops.gc_thresh, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "max_size", + .data = &ip_rt_max_size, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + /* Deprecated. Use gc_min_interval_ms */ + + .procname = "gc_min_interval", + .data = &ip_rt_gc_min_interval, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { + .procname = "gc_min_interval_ms", + .data = &ip_rt_gc_min_interval, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_ms_jiffies, + }, + { + .procname = "gc_timeout", + .data = &ip_rt_gc_timeout, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { + .procname = "gc_interval", + .data = &ip_rt_gc_interval, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { + .procname = "redirect_load", + .data = &ip_rt_redirect_load, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "redirect_number", + .data = &ip_rt_redirect_number, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "redirect_silence", + .data = &ip_rt_redirect_silence, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "error_cost", + .data = &ip_rt_error_cost, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "error_burst", + .data = &ip_rt_error_burst, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "gc_elasticity", + .data = &ip_rt_gc_elasticity, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "mtu_expires", + .data = &ip_rt_mtu_expires, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { + .procname = "min_pmtu", + .data = &ip_rt_min_pmtu, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "min_adv_mss", + .data = &ip_rt_min_advmss, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { } +}; + +static struct ctl_table empty[1]; + +static struct ctl_table ipv4_skeleton[] = +{ + { .procname = "route", + .mode = 0555, .child = ipv4_route_table}, + { .procname = "neigh", + .mode = 0555, .child = empty}, + { } +}; + +static __net_initdata struct ctl_path ipv4_path[] = { + { .procname = "net", }, + { .procname = "ipv4", }, + { }, +}; + +static struct ctl_table ipv4_route_flush_table[] = { + { + .procname = "flush", + .maxlen = sizeof(int), + .mode = 0200, + .proc_handler = ipv4_sysctl_rtcache_flush, + }, + { }, +}; + +static __net_initdata struct ctl_path ipv4_route_path[] = { + { .procname = "net", }, + { .procname = "ipv4", }, + { .procname = "route", }, + { }, +}; + +static __net_init int sysctl_route_net_init(struct net *net) +{ + struct ctl_table *tbl; + + tbl = ipv4_route_flush_table; + if (!net_eq(net, &init_net)) { + tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); + if (tbl == NULL) + goto err_dup; + } + tbl[0].extra1 = net; + + net->ipv4.route_hdr = + register_net_sysctl_table(net, ipv4_route_path, tbl); + if (net->ipv4.route_hdr == NULL) + goto err_reg; + return 0; + +err_reg: + if (tbl != ipv4_route_flush_table) + kfree(tbl); +err_dup: + return -ENOMEM; +} + +static __net_exit void sysctl_route_net_exit(struct net *net) +{ + struct ctl_table *tbl; + + tbl = net->ipv4.route_hdr->ctl_table_arg; + unregister_net_sysctl_table(net->ipv4.route_hdr); + BUG_ON(tbl == ipv4_route_flush_table); + kfree(tbl); +} + +static __net_initdata struct pernet_operations sysctl_route_ops = { + .init = sysctl_route_net_init, + .exit = sysctl_route_net_exit, +}; +#endif + +static __net_init int rt_genid_init(struct net *net) +{ + get_random_bytes(&net->ipv4.rt_genid, + sizeof(net->ipv4.rt_genid)); + get_random_bytes(&net->ipv4.dev_addr_genid, + sizeof(net->ipv4.dev_addr_genid)); + return 0; +} + +static __net_initdata struct pernet_operations rt_genid_ops = { + .init = rt_genid_init, +}; + + +#ifdef CONFIG_IP_ROUTE_CLASSID +struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; +#endif /* CONFIG_IP_ROUTE_CLASSID */ + +static __initdata unsigned long rhash_entries; +static int __init set_rhash_entries(char *str) +{ + if (!str) + return 0; + rhash_entries = simple_strtoul(str, &str, 0); + return 1; +} +__setup("rhash_entries=", set_rhash_entries); + +int __init ip_rt_init(void) +{ + int rc = 0; + +#ifdef CONFIG_IP_ROUTE_CLASSID + ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); + if (!ip_rt_acct) + panic("IP: failed to allocate ip_rt_acct\n"); +#endif + + ipv4_dst_ops.kmem_cachep = + kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); + + ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; + + if (dst_entries_init(&ipv4_dst_ops) < 0) + panic("IP: failed to allocate ipv4_dst_ops counter\n"); + + if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) + panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); + + rt_hash_table = (struct rt_hash_bucket *) + alloc_large_system_hash("IP route cache", + sizeof(struct rt_hash_bucket), + rhash_entries, + (totalram_pages >= 128 * 1024) ? + 15 : 17, + 0, + &rt_hash_log, + &rt_hash_mask, + rhash_entries ? 0 : 512 * 1024); + memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket)); + rt_hash_lock_init(); + + ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1); + ip_rt_max_size = (rt_hash_mask + 1) * 16; + + devinet_init(); + ip_fib_init(); + + INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func); + expires_ljiffies = jiffies; + schedule_delayed_work(&expires_work, + net_random() % ip_rt_gc_interval + ip_rt_gc_interval); + + if (ip_rt_proc_init()) + pr_err("Unable to create route proc files\n"); +#ifdef CONFIG_XFRM + xfrm_init(); + xfrm4_init(ip_rt_max_size); +#endif + rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL); + +#ifdef CONFIG_SYSCTL + register_pernet_subsys(&sysctl_route_ops); +#endif + register_pernet_subsys(&rt_genid_ops); + return rc; +} + +#ifdef CONFIG_SYSCTL +/* + * We really need to sanitize the damn ipv4 init order, then all + * this nonsense will go away. + */ +void __init ip_static_sysctl_init(void) +{ + register_sysctl_paths(ipv4_path, ipv4_skeleton); +} +#endif |