From: David Ahern <dsah...@gmail.com>

Implement kernel side filtering of routes by table id, egress device index,
protocol and route type.

Signed-off-by: David Ahern <dsah...@gmail.com>
---
 include/net/ip_fib.h    |  2 +-
 net/ipv4/fib_frontend.c |  5 ++++-
 net/ipv4/fib_trie.c     | 37 ++++++++++++++++++++++++++-----------
 3 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 9dde41ad02a1..68967f4bd024 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -238,7 +238,7 @@ int fib_table_insert(struct net *, struct fib_table *, 
struct fib_config *,
 int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
                     struct netlink_ext_ack *extack);
 int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
-                  struct netlink_callback *cb);
+                  struct netlink_callback *cb, struct fib_dump_filter *filter);
 int fib_table_flush(struct net *net, struct fib_table *table);
 struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
 void fib_table_flush_external(struct fib_table *table);
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index d0fb9b7efa27..1528b0919951 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -866,10 +866,13 @@ static int inet_dump_fib(struct sk_buff *skb, struct 
netlink_callback *cb)
                hlist_for_each_entry_rcu(tb, head, tb_hlist) {
                        if (e < s_e)
                                goto next;
+                       if (filter.table_id && filter.table_id != tb->tb_id)
+                               goto next;
+
                        if (dumped)
                                memset(&cb->args[2], 0, sizeof(cb->args) -
                                                 2 * sizeof(cb->args[0]));
-                       err = fib_table_dump(tb, skb, cb);
+                       err = fib_table_dump(tb, skb, cb, &filter);
                        if (err < 0) {
                                if (likely(skb->len))
                                        goto out;
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 5bc0c89e81e4..237c9f72b265 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2003,12 +2003,17 @@ void fib_free_table(struct fib_table *tb)
 }
 
 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
-                            struct sk_buff *skb, struct netlink_callback *cb)
+                            struct sk_buff *skb, struct netlink_callback *cb,
+                            struct fib_dump_filter *filter)
 {
+       unsigned int flags = NLM_F_MULTI;
        __be32 xkey = htonl(l->key);
        struct fib_alias *fa;
        int i, s_i;
 
+       if (filter->filter_set)
+               flags |= NLM_F_DUMP_FILTERED;
+
        s_i = cb->args[4];
        i = 0;
 
@@ -2016,25 +2021,35 @@ static int fn_trie_dump_leaf(struct key_vector *l, 
struct fib_table *tb,
        hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
                int err;
 
-               if (i < s_i) {
-                       i++;
-                       continue;
-               }
+               if (i < s_i)
+                       goto next;
 
-               if (tb->tb_id != fa->tb_id) {
-                       i++;
-                       continue;
+               if (tb->tb_id != fa->tb_id)
+                       goto next;
+
+               if (filter->filter_set) {
+                       if (filter->rt_type && fa->fa_type != filter->rt_type)
+                               goto next;
+
+                       if ((filter->protocol &&
+                            fa->fa_info->fib_protocol != filter->protocol))
+                               goto next;
+
+                       if (filter->dev &&
+                           !fib_info_nh_uses_dev(fa->fa_info, filter->dev))
+                               goto next;
                }
 
                err = fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
                                    cb->nlh->nlmsg_seq, RTM_NEWROUTE,
                                    tb->tb_id, fa->fa_type,
                                    xkey, KEYLENGTH - fa->fa_slen,
-                                   fa->fa_tos, fa->fa_info, NLM_F_MULTI);
+                                   fa->fa_tos, fa->fa_info, flags);
                if (err < 0) {
                        cb->args[4] = i;
                        return err;
                }
+next:
                i++;
        }
 
@@ -2044,7 +2059,7 @@ static int fn_trie_dump_leaf(struct key_vector *l, struct 
fib_table *tb,
 
 /* rcu_read_lock needs to be hold by caller from readside */
 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
-                  struct netlink_callback *cb)
+                  struct netlink_callback *cb, struct fib_dump_filter *filter)
 {
        struct trie *t = (struct trie *)tb->tb_data;
        struct key_vector *l, *tp = t->kv;
@@ -2057,7 +2072,7 @@ int fib_table_dump(struct fib_table *tb, struct sk_buff 
*skb,
        while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
                int err;
 
-               err = fn_trie_dump_leaf(l, tb, skb, cb);
+               err = fn_trie_dump_leaf(l, tb, skb, cb, filter);
                if (err < 0) {
                        cb->args[3] = key;
                        cb->args[2] = count;
-- 
2.11.0

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