[PATCH bpf-next v3 07/15] net: bpf: add bpf_seq_afinfo in udp_iter_state

[Yonghong Song]

Similar to tcp_iter_state, a new field bpf_seq_afinfo is
added to udp_iter_state to provide bpf udp iterator
afinfo.

This does not change /proc/net/{udp, udp6} behavior. But
it enables bpf iterator to avoid get afinfo from PDE_DATA
and iterate through all udp and udp6 sockets in one pass.

Acked-by: Martin KaFai Lau <ka...@fb.com>
Signed-off-by: Yonghong Song <y...@fb.com>
---
 include/net/udp.h |  1 +
 net/ipv4/udp.c    | 28 +++++++++++++++++++++++-----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/include/net/udp.h b/include/net/udp.h
index a8fa6c0c6ded..67c8b7368845 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -440,6 +440,7 @@ struct udp_seq_afinfo {
 struct udp_iter_state {
        struct seq_net_private  p;
        int                     bucket;
+       struct udp_seq_afinfo   *bpf_seq_afinfo;
 };
 
 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 1b7ebbcae497..90355301b266 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2826,10 +2826,15 @@ EXPORT_SYMBOL(udp_prot);
 static struct sock *udp_get_first(struct seq_file *seq, int start)
 {
        struct sock *sk;
-       struct udp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
+       struct udp_seq_afinfo *afinfo;
        struct udp_iter_state *state = seq->private;
        struct net *net = seq_file_net(seq);
 
+       if (state->bpf_seq_afinfo)
+               afinfo = state->bpf_seq_afinfo;
+       else
+               afinfo = PDE_DATA(file_inode(seq->file));
+
        for (state->bucket = start; state->bucket <= afinfo->udp_table->mask;
             ++state->bucket) {
                struct udp_hslot *hslot = 
&afinfo->udp_table->hash[state->bucket];
@@ -2841,7 +2846,8 @@ static struct sock *udp_get_first(struct seq_file *seq, 
int start)
                sk_for_each(sk, &hslot->head) {
                        if (!net_eq(sock_net(sk), net))
                                continue;
-                       if (sk->sk_family == afinfo->family)
+                       if (afinfo->family == AF_UNSPEC ||
+                           sk->sk_family == afinfo->family)
                                goto found;
                }
                spin_unlock_bh(&hslot->lock);
@@ -2853,13 +2859,20 @@ static struct sock *udp_get_first(struct seq_file *seq, 
int start)
 
 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
 {
-       struct udp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
+       struct udp_seq_afinfo *afinfo;
        struct udp_iter_state *state = seq->private;
        struct net *net = seq_file_net(seq);
 
+       if (state->bpf_seq_afinfo)
+               afinfo = state->bpf_seq_afinfo;
+       else
+               afinfo = PDE_DATA(file_inode(seq->file));
+
        do {
                sk = sk_next(sk);
-       } while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != 
afinfo->family));
+       } while (sk && (!net_eq(sock_net(sk), net) ||
+                       (afinfo->family != AF_UNSPEC &&
+                        sk->sk_family != afinfo->family)));
 
        if (!sk) {
                if (state->bucket <= afinfo->udp_table->mask)
@@ -2904,9 +2917,14 @@ EXPORT_SYMBOL(udp_seq_next);
 
 void udp_seq_stop(struct seq_file *seq, void *v)
 {
-       struct udp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
+       struct udp_seq_afinfo *afinfo;
        struct udp_iter_state *state = seq->private;
 
+       if (state->bpf_seq_afinfo)
+               afinfo = state->bpf_seq_afinfo;
+       else
+               afinfo = PDE_DATA(file_inode(seq->file));
+
        if (state->bucket <= afinfo->udp_table->mask)
                spin_unlock_bh(&afinfo->udp_table->hash[state->bucket].lock);
 }
-- 
2.24.1