route.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

	struct nlmsghdr  *nlh;
	unsigned char	 *b = skb->tail;
	struct rta_cacheinfo ci;
#ifdef CONFIG_IP_MROUTE
	struct rtattr *eptr;
#endif
	nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(*r));
	r = NLMSG_DATA(nlh);
	nlh->nlmsg_flags = (nowait && pid) ? NLM_F_MULTI : 0;
	r->rtm_family	 = AF_INET;
	r->rtm_dst_len	= 32;
	r->rtm_src_len	= 0;
	r->rtm_tos	= rt->key.tos;
	r->rtm_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;
	RTA_PUT(skb, RTA_DST, 4, &rt->rt_dst);
	if (rt->key.src) {
		r->rtm_src_len = 32;
		RTA_PUT(skb, RTA_SRC, 4, &rt->key.src);
	}
	if (rt->u.dst.dev)
		RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
#ifdef CONFIG_NET_CLS_ROUTE
	if (rt->u.dst.tclassid)
		RTA_PUT(skb, RTA_FLOW, 4, &rt->u.dst.tclassid);
#endif
	if (rt->key.iif)
		RTA_PUT(skb, RTA_PREFSRC, 4, &rt->rt_spec_dst);
	else if (rt->rt_src != rt->key.src)
		RTA_PUT(skb, RTA_PREFSRC, 4, &rt->rt_src);
	if (rt->rt_dst != rt->rt_gateway)
		RTA_PUT(skb, RTA_GATEWAY, 4, &rt->rt_gateway);
	if (rtnetlink_put_metrics(skb, &rt->u.dst.mxlock) < 0)
		goto rtattr_failure;
	ci.rta_lastuse	= jiffies - rt->u.dst.lastuse;
	ci.rta_used	= rt->u.dst.__use;
	ci.rta_clntref	= atomic_read(&rt->u.dst.__refcnt);
	if (rt->u.dst.expires)
		ci.rta_expires = rt->u.dst.expires - jiffies;
	else
		ci.rta_expires = 0;
	ci.rta_error	= rt->u.dst.error;
	ci.rta_id	= ci.rta_ts = ci.rta_tsage = 0;
	if (rt->peer) {
		ci.rta_id = rt->peer->ip_id_count;
		if (rt->peer->tcp_ts_stamp) {
			ci.rta_ts = rt->peer->tcp_ts;
			ci.rta_tsage = xtime.tv_sec - rt->peer->tcp_ts_stamp;
		}
	}
#ifdef CONFIG_IP_MROUTE
	eptr = (struct rtattr*)skb->tail;
#endif
	RTA_PUT(skb, RTA_CACHEINFO, sizeof(ci), &ci);
	if (rt->key.iif) {
#ifdef CONFIG_IP_MROUTE
		u32 dst = rt->rt_dst;

		if (MULTICAST(dst) && !LOCAL_MCAST(dst) &&
		    ipv4_devconf.mc_forwarding) {
			int err = ipmr_get_route(skb, r, nowait);
			if (err <= 0) {
				if (!nowait) {
					if (err == 0)
						return 0;
					goto nlmsg_failure;
				} else {
					if (err == -EMSGSIZE)
						goto nlmsg_failure;
					((struct rta_cacheinfo*)RTA_DATA(eptr))->rta_error = err;
				}
			}
		} else
#endif
			RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->key.iif);
	}

	nlh->nlmsg_len = skb->tail - b;
	return skb->len;

nlmsg_failure:
rtattr_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
{
	struct rtattr **rta = arg;
	struct rtmsg *rtm = NLMSG_DATA(nlh);
	struct rtable *rt = NULL;
	u32 dst = 0;
	u32 src = 0;
	int iif = 0;
	int err = -ENOBUFS;
	struct sk_buff *skb;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		goto out;

	/* Reserve room for dummy headers, this skb can pass
	   through good chunk of routing engine.
	 */
	skb->mac.raw = skb->data;
	skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));

	if (rta[RTA_SRC - 1])
		memcpy(&src, RTA_DATA(rta[RTA_SRC - 1]), 4);
	if (rta[RTA_DST - 1])
		memcpy(&dst, RTA_DATA(rta[RTA_DST - 1]), 4);
	if (rta[RTA_IIF - 1])
		memcpy(&iif, RTA_DATA(rta[RTA_IIF - 1]), sizeof(int));

	if (iif) {
		struct net_device *dev = __dev_get_by_index(iif);
		err = -ENODEV;
		if (!dev)
			goto out;
		skb->protocol	= __constant_htons(ETH_P_IP);
		skb->dev	= dev;
		local_bh_disable();
		err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
		local_bh_enable();
		rt = (struct rtable*)skb->dst;
		if (!err && rt->u.dst.error)
			err = -rt->u.dst.error;
	} else {
		int oif = 0;
		if (rta[RTA_OIF - 1])
			memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
		err = ip_route_output(&rt, dst, src, rtm->rtm_tos, oif);
	}
	if (err) {
		kfree_skb(skb);
		goto out;
	}

	skb->dst = &rt->u.dst;
	if (rtm->rtm_flags & RTM_F_NOTIFY)
		rt->rt_flags |= RTCF_NOTIFY;

	NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;

	err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
				RTM_NEWROUTE, 0);
	if (!err)
		goto out;
	if (err < 0) {
		err = -EMSGSIZE;
		goto out;
	}

	err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
	if (err > 0)
		err = 0;
out:	return err;
}

int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
{
	struct rtable *rt;
	int h, s_h;
	int idx, s_idx;

	s_h = cb->args[0];
	s_idx = idx = cb->args[1];
	for (h = 0; h <= rt_hash_mask; h++) {
		if (h < s_h) continue;
		if (h > s_h)
			s_idx = 0;
		read_lock_bh(&rt_hash_table[h].lock);
		for (rt = rt_hash_table[h].chain, idx = 0; rt;
		     rt = rt->u.rt_next, idx++) {
			if (idx < s_idx)
				continue;
			skb->dst = dst_clone(&rt->u.dst);
			if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
					 cb->nlh->nlmsg_seq,
					 RTM_NEWROUTE, 1) <= 0) {
				dst_release(xchg(&skb->dst, NULL));
				read_unlock_bh(&rt_hash_table[h].lock);
				goto done;
			}
			dst_release(xchg(&skb->dst, NULL));
		}
		read_unlock_bh(&rt_hash_table[h].lock);
	}

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(0);
}

#ifdef CONFIG_SYSCTL
static int flush_delay;

static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write,
					struct file *filp, void *buffer,
					size_t *lenp)
{
	if (write) {
		proc_dointvec(ctl, write, filp, buffer, lenp);
		rt_cache_flush(flush_delay);
		return 0;
	} 

	return -EINVAL;
}

static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table, int *name,
						int nlen, void *oldval,
						size_t *oldlenp, void *newval,
						size_t newlen, void **context)
{
	int delay;
	if (newlen != sizeof(int))
		return -EINVAL;
	if (get_user(delay, (int *)newval))
		return -EFAULT; 
	rt_cache_flush(delay); 
	return 0;
}

ctl_table ipv4_route_table[] = {
        {
		ctl_name:	NET_IPV4_ROUTE_FLUSH,
		procname:	"flush",
		data:		&flush_delay,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&ipv4_sysctl_rtcache_flush,
		strategy:	&ipv4_sysctl_rtcache_flush_strategy,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_MIN_DELAY,
		procname:	"min_delay",
		data:		&ip_rt_min_delay,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec_jiffies,
		strategy:	&sysctl_jiffies,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_MAX_DELAY,
		procname:	"max_delay",
		data:		&ip_rt_max_delay,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec_jiffies,
		strategy:	&sysctl_jiffies,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_GC_THRESH,
		procname:	"gc_thresh",
		data:		&ipv4_dst_ops.gc_thresh,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_MAX_SIZE,
		procname:	"max_size",
		data:		&ip_rt_max_size,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_GC_MIN_INTERVAL,
		procname:	"gc_min_interval",
		data:		&ip_rt_gc_min_interval,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec_jiffies,
		strategy:	&sysctl_jiffies,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_GC_TIMEOUT,
		procname:	"gc_timeout",
		data:		&ip_rt_gc_timeout,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec_jiffies,
		strategy:	&sysctl_jiffies,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_GC_INTERVAL,
		procname:	"gc_interval",
		data:		&ip_rt_gc_interval,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec_jiffies,
		strategy:	&sysctl_jiffies,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_REDIRECT_LOAD,
		procname:	"redirect_load",
		data:		&ip_rt_redirect_load,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_REDIRECT_NUMBER,
		procname:	"redirect_number",
		data:		&ip_rt_redirect_number,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_REDIRECT_SILENCE,
		procname:	"redirect_silence",
		data:		&ip_rt_redirect_silence,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_ERROR_COST,
		procname:	"error_cost",
		data:		&ip_rt_error_cost,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_ERROR_BURST,
		procname:	"error_burst",
		data:		&ip_rt_error_burst,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_GC_ELASTICITY,
		procname:	"gc_elasticity",
		data:		&ip_rt_gc_elasticity,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_MTU_EXPIRES,
		procname:	"mtu_expires",
		data:		&ip_rt_mtu_expires,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec_jiffies,
		strategy:	&sysctl_jiffies,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_MIN_PMTU,
		procname:	"min_pmtu",
		data:		&ip_rt_min_pmtu,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	{
		ctl_name:	NET_IPV4_ROUTE_MIN_ADVMSS,
		procname:	"min_adv_mss",
		data:		&ip_rt_min_advmss,
		maxlen:		sizeof(int),
		mode:		0644,
		proc_handler:	&proc_dointvec,
	},
	 { 0 }
};
#endif

#ifdef CONFIG_NET_CLS_ROUTE
struct ip_rt_acct *ip_rt_acct;

static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
			   int length, int *eof, void *data)
{
	*start = buffer;

	if ((offset & 3) || (length & 3))
		return -EIO;

	if (offset + length >= sizeof(struct ip_rt_acct) * 256) {
		length = sizeof(struct ip_rt_acct) * 256 - offset;
		*eof = 1;
	}
	if (length > 0) {
		u32 *dst = (u32*)buffer;
		u32 *src = (u32*)(((u8*)ip_rt_acct) + offset);

		memcpy(dst, src, length);

#ifdef CONFIG_SMP
		if (smp_num_cpus > 1 || cpu_logical_map(0) != 0) {
			int i;
			int cnt = length / 4;

			for (i = 0; i < smp_num_cpus; i++) {
				int cpu = cpu_logical_map(i);
				int k;

				if (cpu == 0)
					continue;

				src = (u32*)(((u8*)ip_rt_acct) + offset +
					cpu * 256 * sizeof(struct ip_rt_acct));

				for (k = 0; k < cnt; k++)
					dst[k] += src[k];
			}
		}
#endif
		return length;
	}
	return 0;
}
#endif

void __init ip_rt_init(void)
{
	int i, order, goal;

#ifdef CONFIG_NET_CLS_ROUTE
	for (order = 0;
	     (PAGE_SIZE << order) < 256 * sizeof(ip_rt_acct) * NR_CPUS; order++)
		/* NOTHING */;
	ip_rt_acct = (struct ip_rt_acct *)__get_free_pages(GFP_KERNEL, order);
	if (!ip_rt_acct)
		panic("IP: failed to allocate ip_rt_acct\n");
	memset(ip_rt_acct, 0, PAGE_SIZE << order);
#endif

	ipv4_dst_ops.kmem_cachep = kmem_cache_create("ip_dst_cache",
						     sizeof(struct rtable),
						     0, SLAB_HWCACHE_ALIGN,
						     NULL, NULL);

	if (!ipv4_dst_ops.kmem_cachep)
		panic("IP: failed to allocate ip_dst_cache\n");

	goal = num_physpages >> (26 - PAGE_SHIFT);

	for (order = 0; (1UL << order) < goal; order++)
		/* NOTHING */;

	do {
		rt_hash_mask = (1UL << order) * PAGE_SIZE /
			sizeof(struct rt_hash_bucket);
		while (rt_hash_mask & (rt_hash_mask - 1))
			rt_hash_mask--;
		rt_hash_table = (struct rt_hash_bucket *)
			__get_free_pages(GFP_ATOMIC, order);
	} while (rt_hash_table == NULL && --order > 0);

	if (!rt_hash_table)
		panic("Failed to allocate IP route cache hash table\n");

	printk("IP: routing cache hash table of %u buckets, %ldKbytes\n",
	       rt_hash_mask,
	       (long) (rt_hash_mask * sizeof(struct rt_hash_bucket)) / 1024);

	for (rt_hash_log = 0; (1 << rt_hash_log) != rt_hash_mask; rt_hash_log++)
		/* NOTHING */;

	rt_hash_mask--;
	for (i = 0; i <= rt_hash_mask; i++) {
		rt_hash_table[i].lock = RW_LOCK_UNLOCKED;
		rt_hash_table[i].chain = NULL;
	}

	ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
	ip_rt_max_size = (rt_hash_mask + 1) * 16;

	devinet_init();
	ip_fib_init();

	rt_flush_timer.function = rt_run_flush;
	rt_periodic_timer.function = rt_check_expire;

	/* All the timers, started at system startup tend
	   to synchronize. Perturb it a bit.
	 */
	rt_periodic_timer.expires = jiffies + net_random() % ip_rt_gc_interval +
					ip_rt_gc_interval;
	add_timer(&rt_periodic_timer);

	proc_net_create ("rt_cache", 0, rt_cache_get_info);
	proc_net_create ("rt_cache_stat", 0, rt_cache_stat_get_info);
#ifdef CONFIG_NET_CLS_ROUTE
	create_proc_read_entry("net/rt_acct", 0, 0, ip_rt_acct_read, NULL);
#endif
}