cregit-Linux how code gets into the kernel

Release 4.11 net/decnet/dn_route.c

Directory: net/decnet
/*
 * DECnet       An implementation of the DECnet protocol suite for the LINUX
 *              operating system.  DECnet is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              DECnet Routing Functions (Endnode and Router)
 *
 * Authors:     Steve Whitehouse <SteveW@ACM.org>
 *              Eduardo Marcelo Serrat <emserrat@geocities.com>
 *
 * Changes:
 *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
 *                                 "return-to-sender" bits on outgoing
 *                                 packets.
 *              Steve Whitehouse : Timeouts for cached routes.
 *              Steve Whitehouse : Use dst cache for input routes too.
 *              Steve Whitehouse : Fixed error values in dn_send_skb.
 *              Steve Whitehouse : Rework routing functions to better fit
 *                                 DECnet routing design
 *              Alexey Kuznetsov : New SMP locking
 *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
 *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
 *                                 Fixed possible skb leak in rtnetlink funcs.
 *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
 *                                 Alexey Kuznetsov's finer grained locking
 *                                 from ipv4/route.c.
 *              Steve Whitehouse : Routing is now starting to look like a
 *                                 sensible set of code now, mainly due to
 *                                 my copying the IPv4 routing code. The
 *                                 hooks here are modified and will continue
 *                                 to evolve for a while.
 *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
 *                                 stuff. Look out raw sockets your days
 *                                 are numbered!
 *              Steve Whitehouse : Added return-to-sender functions. Added
 *                                 backlog congestion level return codes.
 *              Steve Whitehouse : Fixed bug where routes were set up with
 *                                 no ref count on net devices.
 *              Steve Whitehouse : RCU for the route cache
 *              Steve Whitehouse : Preparations for the flow cache
 *              Steve Whitehouse : Prepare for nonlinear skbs
 */

/******************************************************************************
    (c) 1995-1998 E.M. Serrat           emserrat@geocities.com

    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
    any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*******************************************************************************/

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/inet.h>
#include <linux/route.h>
#include <linux/in_route.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>
#include <linux/string.h>
#include <linux/netfilter_decnet.h>
#include <linux/rcupdate.h>
#include <linux/times.h>
#include <linux/export.h>
#include <asm/errno.h>
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/fib_rules.h>
#include <net/dn.h>
#include <net/dn_dev.h>
#include <net/dn_nsp.h>
#include <net/dn_route.h>
#include <net/dn_neigh.h>
#include <net/dn_fib.h>


struct dn_rt_hash_bucket
{
	
struct dn_route __rcu *chain;
	
spinlock_t lock;
};

extern struct neigh_table dn_neigh_table;



static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};


static const int dn_rt_min_delay = 2 * HZ;

static const int dn_rt_max_delay = 10 * HZ;

static const int dn_rt_mtu_expires = 10 * 60 * HZ;


static unsigned long dn_rt_deadline;

static int dn_dst_gc(struct dst_ops *ops);
static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
static unsigned int dn_dst_mtu(const struct dst_entry *dst);
static void dn_dst_destroy(struct dst_entry *);
static void dn_dst_ifdown(struct dst_entry *, struct net_device *dev, int how);
static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
static void dn_dst_link_failure(struct sk_buff *);
static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
			       struct sk_buff *skb , u32 mtu);
static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
			    struct sk_buff *skb);
static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
					     struct sk_buff *skb,
					     const void *daddr);
static int dn_route_input(struct sk_buff *);
static void dn_run_flush(unsigned long dummy);


static struct dn_rt_hash_bucket *dn_rt_hash_table;

static unsigned int dn_rt_hash_mask;


static struct timer_list dn_route_timer;
static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);

int decnet_dst_gc_interval = 2;


static struct dst_ops dn_dst_ops = {
	.family =		PF_DECnet,
	.gc_thresh =		128,
	.gc =			dn_dst_gc,
	.check =		dn_dst_check,
	.default_advmss =	dn_dst_default_advmss,
	.mtu =			dn_dst_mtu,
	.cow_metrics =		dst_cow_metrics_generic,
	.destroy =		dn_dst_destroy,
	.ifdown =		dn_dst_ifdown,
	.negative_advice =	dn_dst_negative_advice,
	.link_failure =		dn_dst_link_failure,
	.update_pmtu =		dn_dst_update_pmtu,
	.redirect =		dn_dst_redirect,
	.neigh_lookup =		dn_dst_neigh_lookup,
};


static void dn_dst_destroy(struct dst_entry *dst) { struct dn_route *rt = (struct dn_route *) dst; if (rt->n) neigh_release(rt->n); dst_destroy_metrics_generic(dst); }

Contributors

PersonTokensPropCommitsCommitProp
David S. Miller41100.00%2100.00%
Total41100.00%2100.00%


static void dn_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int how) { if (how) { struct dn_route *rt = (struct dn_route *) dst; struct neighbour *n = rt->n; if (n && n->dev == dev) { n->dev = dev_net(dev)->loopback_dev; dev_hold(n->dev); dev_put(dev); } } }

Contributors

PersonTokensPropCommitsCommitProp
David S. Miller81100.00%1100.00%
Total81100.00%1100.00%


static __inline__ unsigned int dn_hash(__le16 src, __le16 dst) { __u16 tmp = (__u16 __force)(src ^ dst); tmp ^= (tmp >> 3); tmp ^= (tmp >> 5); tmp ^= (tmp >> 10); return dn_rt_hash_mask & (unsigned int)tmp; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)4981.67%360.00%
Steven Whitehouse915.00%120.00%
Eric Dumazet23.33%120.00%
Total60100.00%5100.00%


static inline void dnrt_free(struct dn_route *rt) { call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free); }

Contributors

PersonTokensPropCommitsCommitProp
Steven Whitehouse2291.67%133.33%
Dipankar Sarma14.17%133.33%
Andrew Morton14.17%133.33%
Total24100.00%3100.00%


static inline void dnrt_drop(struct dn_route *rt) { dst_release(&rt->dst); call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free); }

Contributors

PersonTokensPropCommitsCommitProp
Steven Whitehouse3093.75%133.33%
Andrew Morton13.12%133.33%
Dipankar Sarma13.12%133.33%
Total32100.00%3100.00%


static void dn_dst_check_expire(unsigned long dummy) { int i; struct dn_route *rt; struct dn_route __rcu **rtp; unsigned long now = jiffies; unsigned long expire = 120 * HZ; for (i = 0; i <= dn_rt_hash_mask; i++) { rtp = &dn_rt_hash_table[i].chain; spin_lock(&dn_rt_hash_table[i].lock); while ((rt = rcu_dereference_protected(*rtp, lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) { if (atomic_read(&rt->dst.__refcnt) || (now - rt->dst.lastuse) < expire) { rtp = &rt->dst.dn_next; continue; } *rtp = rt->dst.dn_next; rt->dst.dn_next = NULL; dnrt_free(rt); } spin_unlock(&dn_rt_hash_table[i].lock); if ((jiffies - now) > 0) break; } mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)16484.54%457.14%
Eric Dumazet2713.92%228.57%
Steven Whitehouse31.55%114.29%
Total194100.00%7100.00%


static int dn_dst_gc(struct dst_ops *ops) { struct dn_route *rt; struct dn_route __rcu **rtp; int i; unsigned long now = jiffies; unsigned long expire = 10 * HZ; for (i = 0; i <= dn_rt_hash_mask; i++) { spin_lock_bh(&dn_rt_hash_table[i].lock); rtp = &dn_rt_hash_table[i].chain; while ((rt = rcu_dereference_protected(*rtp, lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) { if (atomic_read(&rt->dst.__refcnt) || (now - rt->dst.lastuse) < expire) { rtp = &rt->dst.dn_next; continue; } *rtp = rt->dst.dn_next; rt->dst.dn_next = NULL; dnrt_drop(rt); break; } spin_unlock_bh(&dn_rt_hash_table[i].lock); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)14280.68%450.00%
Eric Dumazet2715.34%225.00%
Daniel Lezcano42.27%112.50%
Steven Whitehouse31.70%112.50%
Total176100.00%8100.00%

/* * The decnet standards don't impose a particular minimum mtu, what they * do insist on is that the routing layer accepts a datagram of at least * 230 bytes long. Here we have to subtract the routing header length from * 230 to get the minimum acceptable mtu. If there is no neighbour, then we * assume the worst and use a long header size. * * We update both the mtu and the advertised mss (i.e. the segment size we * advertise to the other end). */
static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb, u32 mtu) { struct dn_route *rt = (struct dn_route *) dst; struct neighbour *n = rt->n; u32 min_mtu = 230; struct dn_dev *dn; dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL; if (dn && dn->use_long == 0) min_mtu -= 6; else min_mtu -= 21; if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) { if (!(dst_metric_locked(dst, RTAX_MTU))) { dst_metric_set(dst, RTAX_MTU, mtu); dst_set_expires(dst, dn_rt_mtu_expires); } if (!(dst_metric_locked(dst, RTAX_ADVMSS))) { u32 mss = mtu - DN_MAX_NSP_DATA_HEADER; u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS); if (!existing_mss || existing_mss > mss) dst_metric_set(dst, RTAX_ADVMSS, mss); } } }

Contributors

PersonTokensPropCommitsCommitProp
Steven Whitehouse11763.24%112.50%
David S. Miller5831.35%562.50%
Satoru SATOH73.78%112.50%
Eric Dumazet31.62%112.50%
Total185100.00%8100.00%


static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) { }

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PersonTokensPropCommitsCommitProp
David S. Miller20100.00%2100.00%
Total20100.00%2100.00%

/* * When a route has been marked obsolete. (e.g. routing cache flush) */
static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie) { return NULL; }

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Linus Torvalds (pre-git)19100.00%1100.00%
Total19100.00%1100.00%


static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst) { dst_release(dst); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)21100.00%1100.00%
Total21100.00%1100.00%


static void dn_dst_link_failure(struct sk_buff *skb) { }

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Linus Torvalds (pre-git)990.00%150.00%
Joe Perches110.00%150.00%
Total10100.00%2100.00%


static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2) { return ((fl1->daddr ^ fl2->daddr) | (fl1->saddr ^ fl2->saddr) | (fl1->flowidn_mark ^ fl2->flowidn_mark) | (fl1->flowidn_scope ^ fl2->flowidn_scope) | (fl1->flowidn_oif ^ fl2->flowidn_oif) | (fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0; }

Contributors

PersonTokensPropCommitsCommitProp
David S. Miller5162.20%266.67%
Steven Whitehouse3137.80%133.33%
Total82100.00%3100.00%


static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp) { struct dn_route *rth; struct dn_route __rcu **rthp; unsigned long now = jiffies; rthp = &dn_rt_hash_table[hash].chain; spin_lock_bh(&dn_rt_hash_table[hash].lock); while ((rth = rcu_dereference_protected(*rthp, lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) { if (compare_keys(&rth->fld, &rt->fld)) { /* Put it first */ *rthp = rth->dst.dn_next; rcu_assign_pointer(rth->dst.dn_next, dn_rt_hash_table[hash].chain); rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth); dst_use(&rth->dst, now); spin_unlock_bh(&dn_rt_hash_table[hash].lock); dnrt_drop(rt); *rp = rth; return 0; } rthp = &rth->dst.dn_next; } rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain); rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt); dst_use(&rt->dst, now); spin_unlock_bh(&dn_rt_hash_table[hash].lock); *rp = rt; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Steven Whitehouse12852.89%19.09%
Linus Torvalds (pre-git)5924.38%436.36%
Eric Dumazet3112.81%327.27%
Paul E. McKenney166.61%19.09%
Pavel Emelyanov62.48%19.09%
David S. Miller20.83%19.09%
Total242100.00%11100.00%


static void dn_run_flush(unsigned long dummy) { int i; struct dn_route *rt, *next; for (i = 0; i < dn_rt_hash_mask; i++) { spin_lock_bh(&dn_rt_hash_table[i].lock); if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL) goto nothing_to_declare; for(; rt; rt = next) { next = rcu_dereference_raw(rt->dst.dn_next); RCU_INIT_POINTER(rt->dst.dn_next, NULL); dst_free((struct