ipv6: add support of equal cost multipath (ECMP) (51ebd318) · Commits · 戴 / test

include/net/ip6_fib.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -47,6 +47,8 @@ struct fib6_config {
		unsigned long fc_expires;
		struct nlattr *fc_mx;
		int fc_mx_len;
		int fc_mp_len;
		struct nlattr *fc_mp;

		struct nl_info fc_nlinfo;
		};
		@@ -99,6 +101,14 @@ struct rt6_info {

		struct in6_addr rt6i_gateway;

		/* Multipath routes:
		* siblings is a list of rt6_info that have the the same metric/weight,
		* destination, but not the same gateway. nsiblings is just a cache
		* to speed up lookup.
		*/
		struct list_head rt6i_siblings;
		unsigned int rt6i_nsiblings;

		atomic_t rt6i_ref;

		/* These are in a separate cache line. */

net/ipv6/ip6_fib.c

+57 −0

Original line number	Diff line number	Diff line
		@@ -672,6 +672,8 @@ static int fib6_add_rt2node(struct fib6_node fn, struct rt6_info rt,
		iter->rt6i_idev == rt->rt6i_idev &&
		ipv6_addr_equal(&iter->rt6i_gateway,
		&rt->rt6i_gateway)) {
		if (rt->rt6i_nsiblings)
		rt->rt6i_nsiblings = 0;
		if (!(iter->rt6i_flags & RTF_EXPIRES))
		return -EEXIST;
		if (!(rt->rt6i_flags & RTF_EXPIRES))
		@@ -680,6 +682,21 @@ static int fib6_add_rt2node(struct fib6_node fn, struct rt6_info rt,
		rt6_set_expires(iter, rt->dst.expires);
		return -EEXIST;
		}
		/* If we have the same destination and the same metric,
		* but not the same gateway, then the route we try to
		* add is sibling to this route, increment our counter
		* of siblings, and later we will add our route to the
		* list.
		* Only static routes (which don't have flag
		* RTF_EXPIRES) are used for ECMPv6.
		*
		* To avoid long list, we only had siblings if the
		* route have a gateway.
		*/
		if (rt->rt6i_flags & RTF_GATEWAY &&
		!(rt->rt6i_flags & RTF_EXPIRES) &&
		!(iter->rt6i_flags & RTF_EXPIRES))
		rt->rt6i_nsiblings++;
		}

		if (iter->rt6i_metric > rt->rt6i_metric)
		@@ -692,6 +709,35 @@ static int fib6_add_rt2node(struct fib6_node fn, struct rt6_info rt,
		if (ins == &fn->leaf)
		fn->rr_ptr = NULL;

		/* Link this route to others same route. */
		if (rt->rt6i_nsiblings) {
		unsigned int rt6i_nsiblings;
		struct rt6_info sibling, temp_sibling;

		/* Find the first route that have the same metric */
		sibling = fn->leaf;
		while (sibling) {
		if (sibling->rt6i_metric == rt->rt6i_metric) {
		list_add_tail(&rt->rt6i_siblings,
		&sibling->rt6i_siblings);
		break;
		}
		sibling = sibling->dst.rt6_next;
		}
		/* For each sibling in the list, increment the counter of
		* siblings. BUG() if counters does not match, list of siblings
		* is broken!
		*/
		rt6i_nsiblings = 0;
		list_for_each_entry_safe(sibling, temp_sibling,
		&rt->rt6i_siblings, rt6i_siblings) {
		sibling->rt6i_nsiblings++;
		BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
		rt6i_nsiblings++;
		}
		BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
		}

		/*
		* insert node
		*/
		@@ -1193,6 +1239,17 @@ static void fib6_del_route(struct fib6_node fn, struct rt6_info *rtp,
		if (fn->rr_ptr == rt)
		fn->rr_ptr = NULL;

		/* Remove this entry from other siblings */
		if (rt->rt6i_nsiblings) {
		struct rt6_info sibling, next_sibling;

		list_for_each_entry_safe(sibling, next_sibling,
		&rt->rt6i_siblings, rt6i_siblings)
		sibling->rt6i_nsiblings--;
		rt->rt6i_nsiblings = 0;
		list_del_init(&rt->rt6i_siblings);
		}

		/* Adjust walkers */
		read_lock(&fib6_walker_lock);
		FOR_WALKERS(w) {

net/ipv6/route.c

+133 −3

Original line number	Diff line number	Diff line
		@@ -57,6 +57,7 @@
		#include <net/xfrm.h>
		#include <net/netevent.h>
		#include <net/netlink.h>
		#include <net/nexthop.h>

		#include <asm/uaccess.h>

		@@ -289,6 +290,8 @@ static inline struct rt6_info ip6_dst_alloc(struct net net,
		memset(dst + 1, 0, sizeof(rt) - sizeof(dst));
		rt6_init_peer(rt, table ? &table->tb6_peers : net->ipv6.peers);
		rt->rt6i_genid = rt_genid(net);
		INIT_LIST_HEAD(&rt->rt6i_siblings);
		rt->rt6i_nsiblings = 0;
		}
		return rt;
		}
		@@ -385,6 +388,69 @@ static bool rt6_need_strict(const struct in6_addr *daddr)
		(IPV6_ADDR_MULTICAST \| IPV6_ADDR_LINKLOCAL \| IPV6_ADDR_LOOPBACK);
		}

		/* Multipath route selection:
		* Hash based function using packet header and flowlabel.
		* Adapted from fib_info_hashfn()
		*/
		static int rt6_info_hash_nhsfn(unsigned int candidate_count,
		const struct flowi6 *fl6)
		{
		unsigned int val = fl6->flowi6_proto;

		val ^= fl6->daddr.s6_addr32[0];
		val ^= fl6->daddr.s6_addr32[1];
		val ^= fl6->daddr.s6_addr32[2];
		val ^= fl6->daddr.s6_addr32[3];

		val ^= fl6->saddr.s6_addr32[0];
		val ^= fl6->saddr.s6_addr32[1];
		val ^= fl6->saddr.s6_addr32[2];
		val ^= fl6->saddr.s6_addr32[3];

		/* Work only if this not encapsulated */
		switch (fl6->flowi6_proto) {
		case IPPROTO_UDP:
		case IPPROTO_TCP:
		case IPPROTO_SCTP:
		val ^= fl6->fl6_sport;
		val ^= fl6->fl6_dport;
		break;

		case IPPROTO_ICMPV6:
		val ^= fl6->fl6_icmp_type;
		val ^= fl6->fl6_icmp_code;
		break;
		}
		/* RFC6438 recommands to use flowlabel */
		val ^= fl6->flowlabel;

		/* Perhaps, we need to tune, this function? */
		val = val ^ (val >> 7) ^ (val >> 12);
		return val % candidate_count;
		}

		static struct rt6_info rt6_multipath_select(struct rt6_info match,
		struct flowi6 *fl6)
		{
		struct rt6_info sibling, next_sibling;
		int route_choosen;

		route_choosen = rt6_info_hash_nhsfn(match->rt6i_nsiblings + 1, fl6);
		/* Don't change the route, if route_choosen == 0
		* (siblings does not include ourself)
		*/
		if (route_choosen)
		list_for_each_entry_safe(sibling, next_sibling,
		&match->rt6i_siblings, rt6i_siblings) {
		route_choosen--;
		if (route_choosen == 0) {
		match = sibling;
		break;
		}
		}
		return match;
		}

		/*
		* Route lookup. Any table->tb6_lock is implied.
		*/
		@@ -702,6 +768,8 @@ static struct rt6_info ip6_pol_route_lookup(struct net net,
		restart:
		rt = fn->leaf;
		rt = rt6_device_match(net, rt, &fl6->saddr, fl6->flowi6_oif, flags);
		if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
		rt = rt6_multipath_select(rt, fl6);
		BACKTRACK(net, &fl6->saddr);
		out:
		dst_use(&rt->dst, jiffies);
		@@ -863,7 +931,8 @@ restart_2:

		restart:
		rt = rt6_select(fn, oif, strict \| reachable);

		if (rt->rt6i_nsiblings && oif == 0)
		rt = rt6_multipath_select(rt, fl6);
		BACKTRACK(net, &fl6->saddr);
		if (rt == net->ipv6.ip6_null_entry \|\|
		rt->rt6i_flags & RTF_CACHE)
		@@ -2249,6 +2318,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
		[RTA_IIF] = { .type = NLA_U32 },
		[RTA_PRIORITY] = { .type = NLA_U32 },
		[RTA_METRICS] = { .type = NLA_NESTED },
		[RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
		};

		static int rtm_to_fib6_config(struct sk_buff skb, struct nlmsghdr nlh,
		@@ -2326,11 +2396,65 @@ static int rtm_to_fib6_config(struct sk_buff skb, struct nlmsghdr nlh,
		if (tb[RTA_TABLE])
		cfg->fc_table = nla_get_u32(tb[RTA_TABLE]);

		if (tb[RTA_MULTIPATH]) {
		cfg->fc_mp = nla_data(tb[RTA_MULTIPATH]);
		cfg->fc_mp_len = nla_len(tb[RTA_MULTIPATH]);
		}

		err = 0;
		errout:
		return err;
		}

		static int ip6_route_multipath(struct fib6_config *cfg, int add)
		{
		struct fib6_config r_cfg;
		struct rtnexthop *rtnh;
		int remaining;
		int attrlen;
		int err = 0, last_err = 0;

		beginning:
		rtnh = (struct rtnexthop *)cfg->fc_mp;
		remaining = cfg->fc_mp_len;

		/* Parse a Multipath Entry */
		while (rtnh_ok(rtnh, remaining)) {
		memcpy(&r_cfg, cfg, sizeof(*cfg));
		if (rtnh->rtnh_ifindex)
		r_cfg.fc_ifindex = rtnh->rtnh_ifindex;

		attrlen = rtnh_attrlen(rtnh);
		if (attrlen > 0) {
		struct nlattr nla, attrs = rtnh_attrs(rtnh);

		nla = nla_find(attrs, attrlen, RTA_GATEWAY);
		if (nla) {
		nla_memcpy(&r_cfg.fc_gateway, nla, 16);
		r_cfg.fc_flags \|= RTF_GATEWAY;
		}
		}
		err = add ? ip6_route_add(&r_cfg) : ip6_route_del(&r_cfg);
		if (err) {
		last_err = err;
		/* If we are trying to remove a route, do not stop the
		* loop when ip6_route_del() fails (because next hop is
		* already gone), we should try to remove all next hops.
		*/
		if (add) {
		/* If add fails, we should try to delete all
		* next hops that have been already added.
		*/
		add = 0;
		goto beginning;
		}
		}
		rtnh = rtnh_next(rtnh, &remaining);
		}

		return last_err;
		}

		static int inet6_rtm_delroute(struct sk_buff skb, struct nlmsghdr nlh, void *arg)
		{
		struct fib6_config cfg;
		@@ -2340,6 +2464,9 @@ static int inet6_rtm_delroute(struct sk_buff skb, struct nlmsghdr nlh, void *a
		if (err < 0)
		return err;

		if (cfg.fc_mp)
		return ip6_route_multipath(&cfg, 0);
		else
		return ip6_route_del(&cfg);
		}

		@@ -2352,6 +2479,9 @@ static int inet6_rtm_newroute(struct sk_buff skb, struct nlmsghdr nlh, void *a
		if (err < 0)
		return err;

		if (cfg.fc_mp)
		return ip6_route_multipath(&cfg, 1);
		else
		return ip6_route_add(&cfg);
		}

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