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Date: Tue, 06 Oct 2015 14:44:10 -0500
From: ebiederm@...ssion.com (Eric W. Biederman)
To: Roopa Prabhu <roopa@...ulusnetworks.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org, rshearma@...cade.com
Subject: Re: [PATCH net-next v2 1/2] mpls: multipath support
Roopa Prabhu <roopa@...ulusnetworks.com> writes:
> From: Roopa Prabhu <roopa@...ulusnetworks.com>
>
> This patch adds support for MPLS multipath routes.
>
> Includes following changes to support multipath:
> - splits struct mpls_route into 'struct mpls_route + struct mpls_nh'
>
> - 'struct mpls_nh' represents a mpls nexthop label forwarding entry
>
> - moves mpls route and nexthop structures into internal.h
>
> - A mpls_route can point to multiple mpls_nh structs
>
> - the nexthops are maintained as a list
So I am not certain I like nexthops being a list. In the practical case
introducing this list guarantees that everyone will see at least an
extra cache line miss in the forwarding path.
In the more abstract sense a list is the wrong data structure. If the
list is so short we can afford to walk it an array is a better data
structure. If we need enough entries to make the memory consumption
of an array a concern we want some kind of hash table or tree data
structure, because a list will be too long in that case.
So can we please not use a list?
I expect we can simplify the data structures by noting that rt_via must
be an ethernet mac today so that 6 bytes are enough and 8 bytes gives us
a bit extra and aligns things nicely.
Also I know it goes away in the next patch but a spinlock taken for
every transit through the forwarding path really bugs me.
Eric
> - In the process of restructuring, this patch also consistently changes all
> labels to u8
>
> - Adds support to parse/fill RTA_MULTIPATH netlink attribute for
> multipath routes similar to ipv4/v6 fib
>
> - In this patch, the multipath route nexthop selection algorithm
> is a simple round robin picked up from ipv4 fib code and is replaced by
> a hash based algorithm from Robert Shearman in the next patch
>
> - mpls_route_update cleanup: remove 'dev' handling in mpls_route_update.
> mpls_route_update though implemented to update based on dev, it was never
> used that way. And the dev handling gets tricky with multiple nexthops. Cannot
> match against any single nexthops dev. So, this patch removes the unused
> 'dev' handling in mpls_route_update.
>
> Example:
>
> $ip -f mpls route add 100 nexthop as 200 via inet 10.1.1.2 dev swp1 \
> nexthop as 700 via inet 10.1.1.6 dev swp2 \
> nexthop as 800 via inet 40.1.1.2 dev swp3
>
> $ip -f mpls route show
> 100
> nexthop as to 200 via inet 10.1.1.2 dev swp1
> nexthop as to 700 via inet 10.1.1.6 dev swp2
> nexthop as to 800 via inet 40.1.1.2 dev swp3
>
> Signed-off-by: Roopa Prabhu <roopa@...ulusnetworks.com>
> ---
> include/net/mpls_iptunnel.h | 2 +-
> net/mpls/af_mpls.c | 627 +++++++++++++++++++++++++++++++++-----------
> net/mpls/internal.h | 43 ++-
> 3 files changed, 516 insertions(+), 156 deletions(-)
>
> diff --git a/include/net/mpls_iptunnel.h b/include/net/mpls_iptunnel.h
> index 4757997..179253f 100644
> --- a/include/net/mpls_iptunnel.h
> +++ b/include/net/mpls_iptunnel.h
> @@ -18,7 +18,7 @@
>
> struct mpls_iptunnel_encap {
> u32 label[MAX_NEW_LABELS];
> - u32 labels;
> + u8 labels;
> };
>
> static inline struct mpls_iptunnel_encap *mpls_lwtunnel_encap(struct lwtunnel_state *lwtstate)
> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
> index 8c5707d..ae9e153 100644
> --- a/net/mpls/af_mpls.c
> +++ b/net/mpls/af_mpls.c
> @@ -19,39 +19,12 @@
> #include <net/ipv6.h>
> #include <net/addrconf.h>
> #endif
> +#include <net/nexthop.h>
> #include "internal.h"
>
> -#define LABEL_NOT_SPECIFIED (1<<20)
> -#define MAX_NEW_LABELS 2
> -
> -/* This maximum ha length copied from the definition of struct neighbour */
> -#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
> -
> -enum mpls_payload_type {
> - MPT_UNSPEC, /* IPv4 or IPv6 */
> - MPT_IPV4 = 4,
> - MPT_IPV6 = 6,
> -
> - /* Other types not implemented:
> - * - Pseudo-wire with or without control word (RFC4385)
> - * - GAL (RFC5586)
> - */
> -};
> -
> -struct mpls_route { /* next hop label forwarding entry */
> - struct net_device __rcu *rt_dev;
> - struct rcu_head rt_rcu;
> - u32 rt_label[MAX_NEW_LABELS];
> - u8 rt_protocol; /* routing protocol that set this entry */
> - u8 rt_payload_type;
> - u8 rt_labels;
> - u8 rt_via_alen;
> - u8 rt_via_table;
> - u8 rt_via[0];
> -};
> -
> static int zero = 0;
> static int label_limit = (1 << 20) - 1;
> +static DEFINE_SPINLOCK(mpls_multipath_lock);
>
> static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
> struct nlmsghdr *nlh, struct net *net, u32 portid,
> @@ -80,10 +53,10 @@ bool mpls_output_possible(const struct net_device *dev)
> }
> EXPORT_SYMBOL_GPL(mpls_output_possible);
>
> -static unsigned int mpls_rt_header_size(const struct mpls_route *rt)
> +static unsigned int mpls_nh_header_size(const struct mpls_nh *nh)
> {
> /* The size of the layer 2.5 labels to be added for this route */
> - return rt->rt_labels * sizeof(struct mpls_shim_hdr);
> + return nh->nh_labels * sizeof(struct mpls_shim_hdr);
> }
>
> unsigned int mpls_dev_mtu(const struct net_device *dev)
> @@ -105,8 +78,58 @@ bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
> }
> EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
>
> -static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
> - struct mpls_entry_decoded dec)
> +/* This is a cut/copy/modify from fib_select_multipath */
> +static struct mpls_nh *mpls_select_multipath(struct mpls_route *rt)
> +{
> + struct mpls_nh *nh;
> + struct mpls_nh *ret_nh;
> + int nhsel = 0;
> + int w;
> +
> + spin_lock_bh(&mpls_multipath_lock);
> + ret_nh = list_first_entry_or_null(&rt->rt_nhs, struct mpls_nh,
> + nh_next);
> + if (rt->rt_power <= 0) {
> + int power = 0;
> +
> + list_for_each_entry(nh, &rt->rt_nhs, nh_next) {
> + power += nh->nh_weight;
> + nh->nh_power = nh->nh_weight;
> + }
> + rt->rt_power = power;
> + if (power <= 0) {
> + spin_unlock_bh(&mpls_multipath_lock);
> + /* Race condition: route has just become dead. */
> + return ret_nh;
> + }
> + }
> +
> + /* w should be random number [0..rt->rt_power-1],
> + * it is pretty bad approximation.
> + */
> + w = jiffies % rt->rt_power;
> +
> + list_for_each_entry(nh, &rt->rt_nhs, nh_next) {
> + if (nh->nh_power) {
> + w -= nh->nh_power;
> + if (w <= 0) {
> + nh->nh_power--;
> + rt->rt_power--;
> + ret_nh = nh;
> + spin_unlock_bh(&mpls_multipath_lock);
> + return ret_nh;
> + }
> + }
> + nhsel++;
> + }
> +
> + /* Race condition: route has just become dead. */
> + spin_unlock_bh(&mpls_multipath_lock);
> + return ret_nh;
> +}
> +
> +static bool mpls_egress(struct mpls_route *rt, struct mpls_nh *nh,
> + struct sk_buff *skb, struct mpls_entry_decoded dec)
> {
> enum mpls_payload_type payload_type;
> bool success = false;
> @@ -159,6 +182,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
> struct net *net = dev_net(dev);
> struct mpls_shim_hdr *hdr;
> struct mpls_route *rt;
> + struct mpls_nh *nh;
> struct mpls_entry_decoded dec;
> struct net_device *out_dev;
> struct mpls_dev *mdev;
> @@ -196,9 +220,13 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
> if (!rt)
> goto drop;
>
> + nh = mpls_select_multipath(rt);
> + if (!nh)
> + goto drop;
> +
> /* Find the output device */
> - out_dev = rcu_dereference(rt->rt_dev);
> - if (!mpls_output_possible(out_dev))
> + out_dev = rcu_dereference(nh->nh_dev);
> + if (!out_dev || !mpls_output_possible(out_dev))
> goto drop;
>
> if (skb_warn_if_lro(skb))
> @@ -212,7 +240,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
> dec.ttl -= 1;
>
> /* Verify the destination can hold the packet */
> - new_header_size = mpls_rt_header_size(rt);
> + new_header_size = mpls_nh_header_size(nh);
> mtu = mpls_dev_mtu(out_dev);
> if (mpls_pkt_too_big(skb, mtu - new_header_size))
> goto drop;
> @@ -230,7 +258,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
>
> if (unlikely(!new_header_size && dec.bos)) {
> /* Penultimate hop popping */
> - if (!mpls_egress(rt, skb, dec))
> + if (!mpls_egress(rt, nh, skb, dec))
> goto drop;
> } else {
> bool bos;
> @@ -240,13 +268,14 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
> /* Push the new labels */
> hdr = mpls_hdr(skb);
> bos = dec.bos;
> - for (i = rt->rt_labels - 1; i >= 0; i--) {
> - hdr[i] = mpls_entry_encode(rt->rt_label[i], dec.ttl, 0, bos);
> + for (i = nh->nh_labels - 1; i >= 0; i--) {
> + hdr[i] = mpls_entry_encode(nh->nh_label[i],
> + dec.ttl, 0, bos);
> bos = false;
> }
> }
>
> - err = neigh_xmit(rt->rt_via_table, out_dev, rt->rt_via, skb);
> + err = neigh_xmit(nh->nh_via_table, out_dev, nh->nh_via, skb);
> if (err)
> net_dbg_ratelimited("%s: packet transmission failed: %d\n",
> __func__, err);
> @@ -270,31 +299,43 @@ static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = {
> struct mpls_route_config {
> u32 rc_protocol;
> u32 rc_ifindex;
> - u16 rc_via_table;
> - u16 rc_via_alen;
> + u8 rc_via_table;
> + u8 rc_via_alen;
> u8 rc_via[MAX_VIA_ALEN];
> + u8 rc_output_labels;
> u32 rc_label;
> - u32 rc_output_labels;
> u32 rc_output_label[MAX_NEW_LABELS];
> u32 rc_nlflags;
> enum mpls_payload_type rc_payload_type;
> struct nl_info rc_nlinfo;
> + struct rtnexthop *rc_mp;
> + int rc_mp_len;
> };
>
> -static struct mpls_route *mpls_rt_alloc(size_t alen)
> +static struct mpls_route *mpls_rt_alloc(int num_nh)
> {
> struct mpls_route *rt;
>
> - rt = kzalloc(sizeof(*rt) + alen, GFP_KERNEL);
> - if (rt)
> - rt->rt_via_alen = alen;
> + rt = kzalloc(sizeof(*rt), GFP_KERNEL);
> + if (rt) {
> + rt->rt_nhn = num_nh;
> + INIT_LIST_HEAD(&rt->rt_nhs);
> + }
> +
> return rt;
> }
>
> static void mpls_rt_free(struct mpls_route *rt)
> {
> - if (rt)
> + struct mpls_nh *nh, *nh_safe;
> +
> + if (rt) {
> + list_for_each_entry_safe(nh, nh_safe, &rt->rt_nhs, nh_next) {
> + list_del(&nh->nh_next);
> + kfree(nh);
> + }
> kfree_rcu(rt, rt_rcu);
> + }
> }
>
> static void mpls_notify_route(struct net *net, unsigned index,
> @@ -312,25 +353,22 @@ static void mpls_notify_route(struct net *net, unsigned index,
> }
>
> static void mpls_route_update(struct net *net, unsigned index,
> - struct net_device *dev, struct mpls_route *new,
> + struct mpls_route *new,
> const struct nl_info *info)
> {
> struct mpls_route __rcu **platform_label;
> - struct mpls_route *rt, *old = NULL;
> + struct mpls_route *rt;
>
> ASSERT_RTNL();
>
> platform_label = rtnl_dereference(net->mpls.platform_label);
> rt = rtnl_dereference(platform_label[index]);
> - if (!dev || (rt && (rtnl_dereference(rt->rt_dev) == dev))) {
> - rcu_assign_pointer(platform_label[index], new);
> - old = rt;
> - }
> + rcu_assign_pointer(platform_label[index], new);
>
> - mpls_notify_route(net, index, old, new, info);
> + mpls_notify_route(net, index, rt, new, info);
>
> /* If we removed a route free it now */
> - mpls_rt_free(old);
> + mpls_rt_free(rt);
> }
>
> static unsigned find_free_label(struct net *net)
> @@ -406,23 +444,23 @@ static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
> #endif
>
> static struct net_device *find_outdev(struct net *net,
> - struct mpls_route_config *cfg)
> + struct mpls_nh *nh, int oif)
> {
> struct net_device *dev = NULL;
>
> - if (!cfg->rc_ifindex) {
> - switch (cfg->rc_via_table) {
> + if (!oif) {
> + switch (nh->nh_via_table) {
> case NEIGH_ARP_TABLE:
> - dev = inet_fib_lookup_dev(net, cfg->rc_via);
> + dev = inet_fib_lookup_dev(net, nh->nh_via);
> break;
> case NEIGH_ND_TABLE:
> - dev = inet6_fib_lookup_dev(net, cfg->rc_via);
> + dev = inet6_fib_lookup_dev(net, nh->nh_via);
> break;
> case NEIGH_LINK_TABLE:
> break;
> }
> } else {
> - dev = dev_get_by_index(net, cfg->rc_ifindex);
> + dev = dev_get_by_index(net, oif);
> }
>
> if (!dev)
> @@ -431,15 +469,208 @@ static struct net_device *find_outdev(struct net *net,
> return dev;
> }
>
> +static int mpls_nh_assign_dev(struct net *net, struct mpls_nh *nh, int oif)
> +{
> + struct net_device *dev = NULL;
> + int err = -ENODEV;
> +
> + dev = find_outdev(net, nh, oif);
> + if (IS_ERR(dev)) {
> + err = PTR_ERR(dev);
> + dev = NULL;
> + goto errout;
> + }
> +
> + /* Ensure this is a supported device */
> + err = -EINVAL;
> + if (!mpls_dev_get(dev))
> + goto errout;
> +
> + RCU_INIT_POINTER(nh->nh_dev, dev);
> + dev_put(dev);
> +
> + return 0;
> +
> +errout:
> + if (dev)
> + dev_put(dev);
> + return err;
> +}
> +
> +static struct mpls_nh *mpls_nh_alloc(size_t alen)
> +{
> + struct mpls_nh *nh;
> +
> + nh = kzalloc(sizeof(*nh) + alen, GFP_KERNEL);
> + if (nh)
> + nh->nh_via_alen = alen;
> +
> + return nh;
> +}
> +
> +static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
> + struct mpls_route *rt)
> +{
> + struct net *net = cfg->rc_nlinfo.nl_net;
> + struct mpls_nh *nh = NULL;
> + int err;
> + int i;
> +
> + err = -EINVAL;
> + /* Ensure only a supported number of labels are present */
> + if (cfg->rc_output_labels > MAX_NEW_LABELS)
> + goto errout;
> +
> + err = -ENOMEM;
> + nh = mpls_nh_alloc(cfg->rc_via_alen);
> + if (!nh)
> + goto errout;
> +
> + nh->nh_labels = cfg->rc_output_labels;
> + for (i = 0; i < nh->nh_labels; i++)
> + nh->nh_label[i] = cfg->rc_output_label[i];
> +
> + nh->nh_via_table = cfg->rc_via_table;
> + memcpy(nh->nh_via, cfg->rc_via, cfg->rc_via_alen);
> + nh->nh_via_alen = cfg->rc_via_alen;
> +
> + err = mpls_nh_assign_dev(net, nh, cfg->rc_ifindex);
> + if (err)
> + goto errout;
> +
> + list_add_tail(&nh->nh_next, &rt->rt_nhs);
> +
> + return 0;
> +
> +errout:
> + kfree(nh);
> +
> + return err;
> +}
> +
> +static int mpls_nh_build(struct net *net, struct mpls_nh **rt_nh,
> + int oif, struct nlattr *via_attr,
> + struct nlattr *newdst)
> +{
> + struct mpls_nh *nh = NULL;
> + int err;
> + u8 via_alen;
> + u8 via_table;
> + u8 via[MAX_VIA_ALEN];
> +
> + err = nla_get_via(via_attr, &via_alen, &via_table,
> + via);
> + if (err)
> + goto errout;
> +
> + nh = mpls_nh_alloc(via_alen);
> + if (!nh)
> + goto errout;
> +
> + if (newdst) {
> + err = nla_get_labels(newdst, MAX_NEW_LABELS,
> + &nh->nh_labels, nh->nh_label);
> + if (err)
> + goto errout;
> + }
> + nh->nh_via_table = via_table;
> + memcpy(nh->nh_via, via, via_alen);
> +
> + err = mpls_nh_assign_dev(net, nh, oif);
> + if (err)
> + goto errout;
> +
> + *rt_nh = nh;
> +
> + return 0;
> +
> +errout:
> + kfree(nh);
> +
> + return err;
> +}
> +
> +static int mpls_count_nexthops(struct rtnexthop *rtnh, int len)
> +{
> + int nhs = 0;
> + int remaining = len;
> +
> + while (rtnh_ok(rtnh, remaining)) {
> + nhs++;
> + rtnh = rtnh_next(rtnh, &remaining);
> + }
> +
> + /* leftover implies invalid nexthop configuration, discard it */
> + return remaining > 0 ? 0 : nhs;
> +}
> +
> +static int mpls_nh_build_multi(struct mpls_route_config *cfg,
> + struct mpls_route *rt)
> +{
> + struct rtnexthop *rtnh = cfg->rc_mp;
> + struct nlattr *nla_via, *nla_newdst;
> + int remaining = cfg->rc_mp_len;
> + struct mpls_nh *nh, *nh_safe;
> + int nhs = 0;
> + int err = 0;
> +
> + while (rtnh_ok(rtnh, remaining)) {
> + int attrlen;
> +
> + nla_via = NULL;
> + nla_newdst = NULL;
> + nh = NULL;
> +
> + err = -EINVAL;
> + if (!rtnh_ok(rtnh, remaining))
> + goto errout;
> +
> + attrlen = rtnh_attrlen(rtnh);
> + if (attrlen > 0) {
> + struct nlattr *attrs = rtnh_attrs(rtnh);
> +
> + nla_via = nla_find(attrs, attrlen, RTA_VIA);
> + nla_newdst = nla_find(attrs, attrlen, RTA_NEWDST);
> + }
> +
> + err = -EINVAL;
> + if (!nla_via)
> + goto errout;
> +
> + err = mpls_nh_build(cfg->rc_nlinfo.nl_net, &nh,
> + rtnh->rtnh_ifindex, nla_via,
> + nla_newdst);
> + if (err)
> + goto errout;
> +
> + nh->nh_weight = rtnh->rtnh_hops + 1;
> + list_add_tail(&nh->nh_next, &rt->rt_nhs);
> +
> + rtnh = rtnh_next(rtnh, &remaining);
> + nhs++;
> + }
> +
> + rt->rt_nhn = nhs;
> +
> + return 0;
> +
> +errout:
> + list_for_each_entry_safe(nh, nh_safe, &rt->rt_nhs, nh_next) {
> + list_del(&nh->nh_next);
> + kfree(nh);
> + }
> +
> + return err;
> +}
> +
> static int mpls_route_add(struct mpls_route_config *cfg)
> {
> struct mpls_route __rcu **platform_label;
> struct net *net = cfg->rc_nlinfo.nl_net;
> - struct net_device *dev = NULL;
> struct mpls_route *rt, *old;
> - unsigned index;
> - int i;
> int err = -EINVAL;
> + unsigned index;
> + int nhs = 1; /* default to one nexthop */
>
> index = cfg->rc_label;
>
> @@ -457,27 +688,6 @@ static int mpls_route_add(struct mpls_route_config *cfg)
> if (index >= net->mpls.platform_labels)
> goto errout;
>
> - /* Ensure only a supported number of labels are present */
> - if (cfg->rc_output_labels > MAX_NEW_LABELS)
> - goto errout;
> -
> - dev = find_outdev(net, cfg);
> - if (IS_ERR(dev)) {
> - err = PTR_ERR(dev);
> - dev = NULL;
> - goto errout;
> - }
> -
> - /* Ensure this is a supported device */
> - err = -EINVAL;
> - if (!mpls_dev_get(dev))
> - goto errout;
> -
> - err = -EINVAL;
> - if ((cfg->rc_via_table == NEIGH_LINK_TABLE) &&
> - (dev->addr_len != cfg->rc_via_alen))
> - goto errout;
> -
> /* Append makes no sense with mpls */
> err = -EOPNOTSUPP;
> if (cfg->rc_nlflags & NLM_F_APPEND)
> @@ -497,28 +707,34 @@ static int mpls_route_add(struct mpls_route_config *cfg)
> if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
> goto errout;
>
> + if (cfg->rc_mp) {
> + err = -EINVAL;
> + nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len);
> + if (nhs == 0)
> + goto errout;
> + }
> +
> err = -ENOMEM;
> - rt = mpls_rt_alloc(cfg->rc_via_alen);
> + rt = mpls_rt_alloc(nhs);
> if (!rt)
> goto errout;
> -
> - rt->rt_labels = cfg->rc_output_labels;
> - for (i = 0; i < rt->rt_labels; i++)
> - rt->rt_label[i] = cfg->rc_output_label[i];
> rt->rt_protocol = cfg->rc_protocol;
> - RCU_INIT_POINTER(rt->rt_dev, dev);
> rt->rt_payload_type = cfg->rc_payload_type;
> - rt->rt_via_table = cfg->rc_via_table;
> - memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);
>
> - mpls_route_update(net, index, NULL, rt, &cfg->rc_nlinfo);
> + if (cfg->rc_mp)
> + err = mpls_nh_build_multi(cfg, rt);
> + else
> + err = mpls_nh_build_from_cfg(cfg, rt);
> + if (err)
> + goto freert;
> +
> + mpls_route_update(net, index, rt, &cfg->rc_nlinfo);
>
> - dev_put(dev);
> return 0;
>
> +freert:
> + mpls_rt_free(rt);
> errout:
> - if (dev)
> - dev_put(dev);
> return err;
> }
>
> @@ -538,7 +754,7 @@ static int mpls_route_del(struct mpls_route_config *cfg)
> if (index >= net->mpls.platform_labels)
> goto errout;
>
> - mpls_route_update(net, index, NULL, NULL, &cfg->rc_nlinfo);
> + mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
>
> err = 0;
> errout:
> @@ -628,6 +844,7 @@ static void mpls_ifdown(struct net_device *dev)
> struct mpls_route __rcu **platform_label;
> struct net *net = dev_net(dev);
> struct mpls_dev *mdev;
> + struct mpls_nh *nh;
> unsigned index;
>
> platform_label = rtnl_dereference(net->mpls.platform_label);
> @@ -635,9 +852,14 @@ static void mpls_ifdown(struct net_device *dev)
> struct mpls_route *rt = rtnl_dereference(platform_label[index]);
> if (!rt)
> continue;
> - if (rtnl_dereference(rt->rt_dev) != dev)
> - continue;
> - rt->rt_dev = NULL;
> + list_for_each_entry(nh, &rt->rt_nhs, nh_next) {
> + struct net_device *mdev;
> +
> + mdev = rtnl_dereference(nh->nh_dev);
> + if (mdev != dev)
> + continue;
> + nh->nh_dev = NULL;
> + }
> }
>
> mdev = mpls_dev_get(dev);
> @@ -736,7 +958,7 @@ int nla_put_labels(struct sk_buff *skb, int attrtype,
> EXPORT_SYMBOL_GPL(nla_put_labels);
>
> int nla_get_labels(const struct nlattr *nla,
> - u32 max_labels, u32 *labels, u32 label[])
> + u8 max_labels, u8 *labels, u32 label[])
> {
> unsigned len = nla_len(nla);
> unsigned nla_labels;
> @@ -781,6 +1003,48 @@ int nla_get_labels(const struct nlattr *nla,
> }
> EXPORT_SYMBOL_GPL(nla_get_labels);
>
> +int nla_get_via(const struct nlattr *nla, u8 *via_alen,
> + u8 *via_table, u8 via_addr[])
> +{
> + struct rtvia *via = nla_data(nla);
> + int err = -EINVAL;
> + u8 alen;
> +
> + if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
> + goto errout;
> + alen = nla_len(nla) -
> + offsetof(struct rtvia, rtvia_addr);
> + if (alen > MAX_VIA_ALEN)
> + goto errout;
> +
> + /* Validate the address family */
> + switch (via->rtvia_family) {
> + case AF_PACKET:
> + *via_table = NEIGH_LINK_TABLE;
> + break;
> + case AF_INET:
> + *via_table = NEIGH_ARP_TABLE;
> + if (alen != 4)
> + goto errout;
> + break;
> + case AF_INET6:
> + *via_table = NEIGH_ND_TABLE;
> + if (alen != 16)
> + goto errout;
> + break;
> + default:
> + /* Unsupported address family */
> + goto errout;
> + }
> +
> + memcpy(via_addr, via->rtvia_addr, alen);
> + *via_alen = alen;
> + err = 0;
> +
> +errout:
> + return err;
> +}
> +
> static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
> struct mpls_route_config *cfg)
> {
> @@ -844,7 +1108,7 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
> break;
> case RTA_DST:
> {
> - u32 label_count;
> + u8 label_count;
> if (nla_get_labels(nla, 1, &label_count,
> &cfg->rc_label))
> goto errout;
> @@ -857,35 +1121,15 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
> }
> case RTA_VIA:
> {
> - struct rtvia *via = nla_data(nla);
> - if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
> + if (nla_get_via(nla, &cfg->rc_via_alen,
> + &cfg->rc_via_table, cfg->rc_via))
> goto errout;
> - cfg->rc_via_alen = nla_len(nla) -
> - offsetof(struct rtvia, rtvia_addr);
> - if (cfg->rc_via_alen > MAX_VIA_ALEN)
> - goto errout;
> -
> - /* Validate the address family */
> - switch(via->rtvia_family) {
> - case AF_PACKET:
> - cfg->rc_via_table = NEIGH_LINK_TABLE;
> - break;
> - case AF_INET:
> - cfg->rc_via_table = NEIGH_ARP_TABLE;
> - if (cfg->rc_via_alen != 4)
> - goto errout;
> - break;
> - case AF_INET6:
> - cfg->rc_via_table = NEIGH_ND_TABLE;
> - if (cfg->rc_via_alen != 16)
> - goto errout;
> - break;
> - default:
> - /* Unsupported address family */
> - goto errout;
> - }
> -
> - memcpy(cfg->rc_via, via->rtvia_addr, cfg->rc_via_alen);
> + break;
> + }
> + case RTA_MULTIPATH:
> + {
> + cfg->rc_mp = nla_data(nla);
> + cfg->rc_mp_len = nla_len(nla);
> break;
> }
> default:
> @@ -946,16 +1190,56 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
> rtm->rtm_type = RTN_UNICAST;
> rtm->rtm_flags = 0;
>
> - if (rt->rt_labels &&
> - nla_put_labels(skb, RTA_NEWDST, rt->rt_labels, rt->rt_label))
> - goto nla_put_failure;
> - if (nla_put_via(skb, rt->rt_via_table, rt->rt_via, rt->rt_via_alen))
> - goto nla_put_failure;
> - dev = rtnl_dereference(rt->rt_dev);
> - if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
> - goto nla_put_failure;
> if (nla_put_labels(skb, RTA_DST, 1, &label))
> goto nla_put_failure;
> + if (rt->rt_nhn == 1) {
> + struct mpls_nh *nh = list_first_entry_or_null(&rt->rt_nhs,
> + struct mpls_nh,
> + nh_next);
> +
> + if (nh->nh_labels &&
> + nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
> + nh->nh_label))
> + goto nla_put_failure;
> + if (nla_put_via(skb, nh->nh_via_table, nh->nh_via,
> + nh->nh_via_alen))
> + goto nla_put_failure;
> + dev = rtnl_dereference(nh->nh_dev);
> + if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
> + goto nla_put_failure;
> + } else {
> + struct rtnexthop *rtnh;
> + struct nlattr *mp;
> + struct mpls_nh *nh;
> +
> + mp = nla_nest_start(skb, RTA_MULTIPATH);
> + if (!mp)
> + goto nla_put_failure;
> +
> + list_for_each_entry(nh, &rt->rt_nhs, nh_next) {
> + rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
> + if (!rtnh)
> + goto nla_put_failure;
> +
> + rtnh->rtnh_flags = nh->nh_flags & 0xFF;
> + dev = rtnl_dereference(nh->nh_dev);
> + if (dev)
> + rtnh->rtnh_ifindex = dev->ifindex;
> + if (nh->nh_labels &&
> + nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
> + nh->nh_label))
> + goto nla_put_failure;
> + if (nla_put_via(skb, nh->nh_via_table,
> + nh->nh_via,
> + nh->nh_via_alen))
> + goto nla_put_failure;
> +
> + /* length of rtnetlink header + attributes */
> + rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
> + }
> +
> + nla_nest_end(skb, mp);
> + }
>
> nlmsg_end(skb, nlh);
> return 0;
> @@ -1000,12 +1284,34 @@ static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
> {
> size_t payload =
> NLMSG_ALIGN(sizeof(struct rtmsg))
> - + nla_total_size(2 + rt->rt_via_alen) /* RTA_VIA */
> + nla_total_size(4); /* RTA_DST */
> - if (rt->rt_labels) /* RTA_NEWDST */
> - payload += nla_total_size(rt->rt_labels * 4);
> - if (rt->rt_dev) /* RTA_OIF */
> - payload += nla_total_size(4);
> +
> + if (rt->rt_nhn == 1) {
> + struct mpls_nh *nh = list_first_entry_or_null(&rt->rt_nhs,
> + struct mpls_nh,
> + nh_next);
> +
> + if (nh->nh_dev)
> + payload += nla_total_size(4); /* RTA_OIF */
> + payload += nla_total_size(2 + nh->nh_via_alen); /* RTA_VIA */
> + if (nh->nh_labels) /* RTA_NEWDST */
> + payload += nla_total_size(nh->nh_labels * 4);
> + } else {
> + struct mpls_nh *nh;
> + /* each nexthop is packed in an attribute */
> + size_t nhsize = 0;
> +
> + list_for_each_entry(nh, &rt->rt_nhs, nh_next) {
> + nhsize += nla_total_size(sizeof(struct rtnexthop)) +
> + nla_total_size(nh->nh_via_alen +
> + 2); /* RTA_VIA */
> + if (nh->nh_labels) /* RTA_NEWDST */
> + nhsize += nla_total_size(nh->nh_labels * 4);
> + }
> + /* nested attribute */
> + payload += nla_total_size(nhsize);
> + }
> +
> return payload;
> }
>
> @@ -1057,25 +1363,37 @@ static int resize_platform_label_table(struct net *net, size_t limit)
> /* In case the predefined labels need to be populated */
> if (limit > MPLS_LABEL_IPV4NULL) {
> struct net_device *lo = net->loopback_dev;
> - rt0 = mpls_rt_alloc(lo->addr_len);
> + struct mpls_nh *nh;
> +
> + rt0 = mpls_rt_alloc(1);
> if (!rt0)
> goto nort0;
> - RCU_INIT_POINTER(rt0->rt_dev, lo);
> rt0->rt_protocol = RTPROT_KERNEL;
> rt0->rt_payload_type = MPT_IPV4;
> - rt0->rt_via_table = NEIGH_LINK_TABLE;
> - memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
> + nh = mpls_nh_alloc(lo->addr_len);
> + if (!nh)
> + goto nort2;
> + RCU_INIT_POINTER(nh->nh_dev, lo);
> + nh->nh_via_table = NEIGH_LINK_TABLE;
> + memcpy(nh->nh_via, lo->dev_addr, lo->addr_len);
> + list_add_tail(&nh->nh_next, &rt0->rt_nhs);
> }
> if (limit > MPLS_LABEL_IPV6NULL) {
> struct net_device *lo = net->loopback_dev;
> - rt2 = mpls_rt_alloc(lo->addr_len);
> + struct mpls_nh *nh;
> +
> + rt2 = mpls_rt_alloc(1);
> if (!rt2)
> goto nort2;
> - RCU_INIT_POINTER(rt2->rt_dev, lo);
> rt2->rt_protocol = RTPROT_KERNEL;
> rt2->rt_payload_type = MPT_IPV6;
> - rt2->rt_via_table = NEIGH_LINK_TABLE;
> - memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
> + nh = mpls_nh_alloc(lo->addr_len);
> + if (!nh)
> + goto nort2;
> + RCU_INIT_POINTER(nh->nh_dev, lo);
> + nh->nh_via_table = NEIGH_LINK_TABLE;
> + memcpy(nh->nh_via, lo->dev_addr, lo->addr_len);
> + list_add_tail(&nh->nh_next, &rt2->rt_nhs);
> }
>
> rtnl_lock();
> @@ -1085,7 +1403,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
>
> /* Free any labels beyond the new table */
> for (index = limit; index < old_limit; index++)
> - mpls_route_update(net, index, NULL, NULL, NULL);
> + mpls_route_update(net, index, NULL, NULL);
>
> /* Copy over the old labels */
> cp_size = size;
> @@ -1124,6 +1442,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
>
> nort2:
> mpls_rt_free(rt0);
> + mpls_rt_free(rt2);
> nort0:
> kvfree(labels);
> nolabels:
> diff --git a/net/mpls/internal.h b/net/mpls/internal.h
> index 2681a4b..9e18b58 100644
> --- a/net/mpls/internal.h
> +++ b/net/mpls/internal.h
> @@ -1,6 +1,17 @@
> #ifndef MPLS_INTERNAL_H
> #define MPLS_INTERNAL_H
>
> +enum mpls_payload_type {
> + MPT_UNSPEC, /* IPv4 or IPv6 */
> + MPT_IPV4 = 4,
> + MPT_IPV6 = 6,
> +
> + /* Other types not implemented:
> + * - Pseudo-wire with or without control word (RFC4385)
> + * - GAL (RFC5586)
> + */
> +};
> +
> struct mpls_shim_hdr {
> __be32 label_stack_entry;
> };
> @@ -21,6 +32,34 @@ struct mpls_dev {
>
> struct sk_buff;
>
> +#define LABEL_NOT_SPECIFIED (1 << 20)
> +#define MAX_NEW_LABELS 2
> +
> +/* This maximum ha length copied from the definition of struct neighbour */
> +#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
> +
> +struct mpls_nh {
> + struct net_device __rcu *nh_dev;
> + u32 nh_label[MAX_NEW_LABELS];
> + unsigned int nh_flags;
> + int nh_weight;
> + int nh_power;
> + struct list_head nh_next;
> + u8 nh_labels;
> + u8 nh_via_alen;
> + u8 nh_via_table;
> + u8 nh_via[0];
> +};
> +
> +struct mpls_route {
> + struct rcu_head rt_rcu;
> + u8 rt_protocol;
> + u8 rt_payload_type;
> + int rt_power;
> + int rt_nhn;
> + struct list_head rt_nhs;
> +};
> +
> static inline struct mpls_shim_hdr *mpls_hdr(const struct sk_buff *skb)
> {
> return (struct mpls_shim_hdr *)skb_network_header(skb);
> @@ -52,8 +91,10 @@ static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *
>
> int nla_put_labels(struct sk_buff *skb, int attrtype, u8 labels,
> const u32 label[]);
> -int nla_get_labels(const struct nlattr *nla, u32 max_labels, u32 *labels,
> +int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
> u32 label[]);
> +int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
> + u8 via[]);
> bool mpls_output_possible(const struct net_device *dev);
> unsigned int mpls_dev_mtu(const struct net_device *dev);
> bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);
--
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