Implement the netlink messages that allow creation and dumping of resilient
nexthop groups.

Signed-off-by: Petr Machata <pe...@nvidia.com>
Reviewed-by: Ido Schimmel <ido...@nvidia.com>
Reviewed-by: David Ahern <dsah...@kernel.org>
---

Notes:
    v1 (changes since RFC):
    - u32 -> u16 for bucket counts / indices

 net/ipv4/nexthop.c | 150 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 145 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 495b5e69ffcd..439bf3b7ced5 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -16,6 +16,9 @@
 #include <net/route.h>
 #include <net/sock.h>
 
+#define NH_RES_DEFAULT_IDLE_TIMER      (120 * HZ)
+#define NH_RES_DEFAULT_UNBALANCED_TIMER        0       /* No forced 
rebalancing. */
+
 static void remove_nexthop(struct net *net, struct nexthop *nh,
                           struct nl_info *nlinfo);
 
@@ -32,6 +35,7 @@ static const struct nla_policy rtm_nh_policy_new[] = {
        [NHA_ENCAP_TYPE]        = { .type = NLA_U16 },
        [NHA_ENCAP]             = { .type = NLA_NESTED },
        [NHA_FDB]               = { .type = NLA_FLAG },
+       [NHA_RES_GROUP]         = { .type = NLA_NESTED },
 };
 
 static const struct nla_policy rtm_nh_policy_get[] = {
@@ -45,6 +49,12 @@ static const struct nla_policy rtm_nh_policy_dump[] = {
        [NHA_FDB]               = { .type = NLA_FLAG },
 };
 
+static const struct nla_policy rtm_nh_res_policy_new[] = {
+       [NHA_RES_GROUP_BUCKETS]                 = { .type = NLA_U16 },
+       [NHA_RES_GROUP_IDLE_TIMER]              = { .type = NLA_U32 },
+       [NHA_RES_GROUP_UNBALANCED_TIMER]        = { .type = NLA_U32 },
+};
+
 static bool nexthop_notifiers_is_empty(struct net *net)
 {
        return !net->nexthop.notifier_chain.head;
@@ -588,6 +598,41 @@ static void nh_res_time_set_deadline(unsigned long 
next_time,
                *deadline = next_time;
 }
 
+static clock_t nh_res_table_unbalanced_time(struct nh_res_table *res_table)
+{
+       if (list_empty(&res_table->uw_nh_entries))
+               return 0;
+       return jiffies_delta_to_clock_t(jiffies - res_table->unbalanced_since);
+}
+
+static int nla_put_nh_group_res(struct sk_buff *skb, struct nh_group *nhg)
+{
+       struct nh_res_table *res_table = rtnl_dereference(nhg->res_table);
+       struct nlattr *nest;
+
+       nest = nla_nest_start(skb, NHA_RES_GROUP);
+       if (!nest)
+               return -EMSGSIZE;
+
+       if (nla_put_u16(skb, NHA_RES_GROUP_BUCKETS,
+                       res_table->num_nh_buckets) ||
+           nla_put_u32(skb, NHA_RES_GROUP_IDLE_TIMER,
+                       jiffies_to_clock_t(res_table->idle_timer)) ||
+           nla_put_u32(skb, NHA_RES_GROUP_UNBALANCED_TIMER,
+                       jiffies_to_clock_t(res_table->unbalanced_timer)) ||
+           nla_put_u64_64bit(skb, NHA_RES_GROUP_UNBALANCED_TIME,
+                             nh_res_table_unbalanced_time(res_table),
+                             NHA_RES_GROUP_PAD))
+               goto nla_put_failure;
+
+       nla_nest_end(skb, nest);
+       return 0;
+
+nla_put_failure:
+       nla_nest_cancel(skb, nest);
+       return -EMSGSIZE;
+}
+
 static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg)
 {
        struct nexthop_grp *p;
@@ -598,6 +643,8 @@ static int nla_put_nh_group(struct sk_buff *skb, struct 
nh_group *nhg)
 
        if (nhg->mpath)
                group_type = NEXTHOP_GRP_TYPE_MPATH;
+       else if (nhg->resilient)
+               group_type = NEXTHOP_GRP_TYPE_RES;
 
        if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type))
                goto nla_put_failure;
@@ -613,6 +660,9 @@ static int nla_put_nh_group(struct sk_buff *skb, struct 
nh_group *nhg)
                p += 1;
        }
 
+       if (nhg->resilient && nla_put_nh_group_res(skb, nhg))
+               goto nla_put_failure;
+
        return 0;
 
 nla_put_failure:
@@ -700,13 +750,26 @@ static int nh_fill_node(struct sk_buff *skb, struct 
nexthop *nh,
        return -EMSGSIZE;
 }
 
+static size_t nh_nlmsg_size_grp_res(struct nh_group *nhg)
+{
+       return nla_total_size(0) +      /* NHA_RES_GROUP */
+               nla_total_size(2) +     /* NHA_RES_GROUP_BUCKETS */
+               nla_total_size(4) +     /* NHA_RES_GROUP_IDLE_TIMER */
+               nla_total_size(4) +     /* NHA_RES_GROUP_UNBALANCED_TIMER */
+               nla_total_size_64bit(8);/* NHA_RES_GROUP_UNBALANCED_TIME */
+}
+
 static size_t nh_nlmsg_size_grp(struct nexthop *nh)
 {
        struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
        size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh;
+       size_t tot = nla_total_size(sz) +
+               nla_total_size(2); /* NHA_GROUP_TYPE */
+
+       if (nhg->resilient)
+               tot += nh_nlmsg_size_grp_res(nhg);
 
-       return nla_total_size(sz) +
-              nla_total_size(2);  /* NHA_GROUP_TYPE */
+       return tot;
 }
 
 static size_t nh_nlmsg_size_single(struct nexthop *nh)
@@ -876,7 +939,7 @@ static int nh_check_attr_fdb_group(struct nexthop *nh, u8 
*nh_family,
 
 static int nh_check_attr_group(struct net *net,
                               struct nlattr *tb[], size_t tb_size,
-                              struct netlink_ext_ack *extack)
+                              u16 nh_grp_type, struct netlink_ext_ack *extack)
 {
        unsigned int len = nla_len(tb[NHA_GROUP]);
        u8 nh_family = AF_UNSPEC;
@@ -937,8 +1000,14 @@ static int nh_check_attr_group(struct net *net,
        for (i = NHA_GROUP_TYPE + 1; i < tb_size; ++i) {
                if (!tb[i])
                        continue;
-               if (i == NHA_FDB)
+               switch (i) {
+               case NHA_FDB:
                        continue;
+               case NHA_RES_GROUP:
+                       if (nh_grp_type == NEXTHOP_GRP_TYPE_RES)
+                               continue;
+                       break;
+               }
                NL_SET_ERR_MSG(extack,
                               "No other attributes can be set in nexthop 
groups");
                return -EINVAL;
@@ -2475,6 +2544,70 @@ static struct nexthop *nexthop_add(struct net *net, 
struct nh_config *cfg,
        return nh;
 }
 
+static int rtm_nh_get_timer(struct nlattr *attr, unsigned long fallback,
+                           unsigned long *timer_p, bool *has_p,
+                           struct netlink_ext_ack *extack)
+{
+       unsigned long timer;
+       u32 value;
+
+       if (!attr) {
+               *timer_p = fallback;
+               *has_p = false;
+               return 0;
+       }
+
+       value = nla_get_u32(attr);
+       timer = clock_t_to_jiffies(value);
+       if (timer == ~0UL) {
+               NL_SET_ERR_MSG(extack, "Timer value too large");
+               return -EINVAL;
+       }
+
+       *timer_p = timer;
+       *has_p = true;
+       return 0;
+}
+
+static int rtm_to_nh_config_grp_res(struct nlattr *res, struct nh_config *cfg,
+                                   struct netlink_ext_ack *extack)
+{
+       struct nlattr *tb[ARRAY_SIZE(rtm_nh_res_policy_new)] = {};
+       int err;
+
+       if (res) {
+               err = nla_parse_nested(tb,
+                                      ARRAY_SIZE(rtm_nh_res_policy_new) - 1,
+                                      res, rtm_nh_res_policy_new, extack);
+               if (err < 0)
+                       return err;
+       }
+
+       if (tb[NHA_RES_GROUP_BUCKETS]) {
+               cfg->nh_grp_res_num_buckets =
+                       nla_get_u16(tb[NHA_RES_GROUP_BUCKETS]);
+               cfg->nh_grp_res_has_num_buckets = true;
+               if (!cfg->nh_grp_res_num_buckets) {
+                       NL_SET_ERR_MSG(extack, "Number of buckets needs to be 
non-0");
+                       return -EINVAL;
+               }
+       }
+
+       err = rtm_nh_get_timer(tb[NHA_RES_GROUP_IDLE_TIMER],
+                              NH_RES_DEFAULT_IDLE_TIMER,
+                              &cfg->nh_grp_res_idle_timer,
+                              &cfg->nh_grp_res_has_idle_timer,
+                              extack);
+       if (err)
+               return err;
+
+       return rtm_nh_get_timer(tb[NHA_RES_GROUP_UNBALANCED_TIMER],
+                               NH_RES_DEFAULT_UNBALANCED_TIMER,
+                               &cfg->nh_grp_res_unbalanced_timer,
+                               &cfg->nh_grp_res_has_unbalanced_timer,
+                               extack);
+}
+
 static int rtm_to_nh_config(struct net *net, struct sk_buff *skb,
                            struct nlmsghdr *nlh, struct nh_config *cfg,
                            struct netlink_ext_ack *extack)
@@ -2553,7 +2686,14 @@ static int rtm_to_nh_config(struct net *net, struct 
sk_buff *skb,
                        NL_SET_ERR_MSG(extack, "Invalid group type");
                        goto out;
                }
-               err = nh_check_attr_group(net, tb, ARRAY_SIZE(tb), extack);
+               err = nh_check_attr_group(net, tb, ARRAY_SIZE(tb),
+                                         cfg->nh_grp_type, extack);
+               if (err)
+                       goto out;
+
+               if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_RES)
+                       err = rtm_to_nh_config_grp_res(tb[NHA_RES_GROUP],
+                                                      cfg, extack);
 
                /* no other attributes should be set */
                goto out;
-- 
2.26.2

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