tcp: seq_file: Refactor net and family matching

This patch refactors the net and family matching into
two new helpers, seq_sk_match() and seq_file_family().

seq_file_family() is in the later part of the file to prepare
the change of a following patch.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200548.1034629-1-kafai@fb.com

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ee85abde968c6f65d50de20bb7bd710f55a97401..f2583c4699fd452c54b5a6716fa9701a64d0a36d 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2277,6 +2277,17 @@ EXPORT_SYMBOL(tcp_v4_destroy_sock);
 #ifdef CONFIG_PROC_FS
 /* Proc filesystem TCP sock list dumping. */
 
+static unsigned short seq_file_family(const struct seq_file *seq);
+
+static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
+{
+       unsigned short family = seq_file_family(seq);
+
+       /* AF_UNSPEC is used as a match all */
+       return ((family == AF_UNSPEC || family == sk->sk_family) &&
+               net_eq(sock_net(sk), seq_file_net(seq)));
+}
+
 /*
  * Get next listener socket follow cur.  If cur is NULL, get first socket
  * starting from bucket given in st->bucket; when st->bucket is zero the
@@ -2284,18 +2295,11 @@ EXPORT_SYMBOL(tcp_v4_destroy_sock);
  */
 static void *listening_get_next(struct seq_file *seq, void *cur)
 {
-       struct tcp_seq_afinfo *afinfo;
        struct tcp_iter_state *st = seq->private;
-       struct net *net = seq_file_net(seq);
        struct inet_listen_hashbucket *ilb;
        struct hlist_nulls_node *node;
        struct sock *sk = cur;
 
-       if (st->bpf_seq_afinfo)
-               afinfo = st->bpf_seq_afinfo;
-       else
-               afinfo = PDE_DATA(file_inode(seq->file));
-
        if (!sk) {
 get_head:
                ilb = &tcp_hashinfo.listening_hash[st->bucket];
@@ -2311,10 +2315,7 @@ get_head:
        sk = sk_nulls_next(sk);
 get_sk:
        sk_nulls_for_each_from(sk, node) {
-               if (!net_eq(sock_net(sk), net))
-                       continue;
-               if (afinfo->family == AF_UNSPEC ||
-                   sk->sk_family == afinfo->family)
+               if (seq_sk_match(seq, sk))
                        return sk;
        }
        spin_unlock(&ilb->lock);
@@ -2351,15 +2352,7 @@ static inline bool empty_bucket(const struct tcp_iter_state *st)
  */
 static void *established_get_first(struct seq_file *seq)
 {
-       struct tcp_seq_afinfo *afinfo;
        struct tcp_iter_state *st = seq->private;
-       struct net *net = seq_file_net(seq);
-       void *rc = NULL;
-
-       if (st->bpf_seq_afinfo)
-               afinfo = st->bpf_seq_afinfo;
-       else
-               afinfo = PDE_DATA(file_inode(seq->file));
 
        st->offset = 0;
        for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
@@ -2373,32 +2366,20 @@ static void *established_get_first(struct seq_file *seq)
 
                spin_lock_bh(lock);
                sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
-                       if ((afinfo->family != AF_UNSPEC &&
-                            sk->sk_family != afinfo->family) ||
-                           !net_eq(sock_net(sk), net)) {
-                               continue;
-                       }
-                       rc = sk;
-                       goto out;
+                       if (seq_sk_match(seq, sk))
+                               return sk;
                }
                spin_unlock_bh(lock);
        }
-out:
-       return rc;
+
+       return NULL;
 }
 
 static void *established_get_next(struct seq_file *seq, void *cur)
 {
-       struct tcp_seq_afinfo *afinfo;
        struct sock *sk = cur;
        struct hlist_nulls_node *node;
        struct tcp_iter_state *st = seq->private;
-       struct net *net = seq_file_net(seq);
-
-       if (st->bpf_seq_afinfo)
-               afinfo = st->bpf_seq_afinfo;
-       else
-               afinfo = PDE_DATA(file_inode(seq->file));
 
        ++st->num;
        ++st->offset;
@@ -2406,9 +2387,7 @@ static void *established_get_next(struct seq_file *seq, void *cur)
        sk = sk_nulls_next(sk);
 
        sk_nulls_for_each_from(sk, node) {
-               if ((afinfo->family == AF_UNSPEC ||
-                    sk->sk_family == afinfo->family) &&
-                   net_eq(sock_net(sk), net))
+               if (seq_sk_match(seq, sk))
                        return sk;
        }
 
@@ -2754,6 +2733,19 @@ static const struct seq_operations bpf_iter_tcp_seq_ops = {
        .stop           = bpf_iter_tcp_seq_stop,
 };
 #endif
+static unsigned short seq_file_family(const struct seq_file *seq)
+{
+       const struct tcp_iter_state *st = seq->private;
+       const struct tcp_seq_afinfo *afinfo = st->bpf_seq_afinfo;
+
+       /* Iterated from bpf_iter.  Let the bpf prog to filter instead. */
+       if (afinfo)
+               return AF_UNSPEC;
+
+       /* Iterated from proc fs */
+       afinfo = PDE_DATA(file_inode(seq->file));
+       return afinfo->family;
+}
 
 static const struct seq_operations tcp4_seq_ops = {
        .show           = tcp4_seq_show,