[PATCH bpf-next 03/17] inet: Store layer 4 protocol in inet_hashinfo

[Jakub Sitnicki]

Make it possible to identify the protocol of sockets stored in hashinfo
without looking up a socket.

Subsequent patches make use the new field at the socket lookup time to
ensure that BPF program selects only sockets with matching protocol.

Reviewed-by: Lorenz Bauer <l...@cloudflare.com>
Signed-off-by: Jakub Sitnicki <ja...@cloudflare.com>
---
 include/net/inet_hashtables.h | 3 +++
 net/dccp/proto.c              | 2 +-
 net/ipv4/tcp_ipv4.c           | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index ad64ba6a057f..6072dfbd1078 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -144,6 +144,9 @@ struct inet_hashinfo {
        unsigned int                    lhash2_mask;
        struct inet_listen_hashbucket   *lhash2;
 
+       /* Layer 4 protocol of the stored sockets */
+       int                             protocol;
+
        /* All the above members are written once at bootup and
         * never written again _or_ are predominantly read-access.
         *
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 4af8a98fe784..c826419e68e6 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -45,7 +45,7 @@ EXPORT_SYMBOL_GPL(dccp_statistics);
 struct percpu_counter dccp_orphan_count;
 EXPORT_SYMBOL_GPL(dccp_orphan_count);
 
-struct inet_hashinfo dccp_hashinfo;
+struct inet_hashinfo dccp_hashinfo = { .protocol = IPPROTO_DCCP };
 EXPORT_SYMBOL_GPL(dccp_hashinfo);
 
 /* the maximum queue length for tx in packets. 0 is no limit */
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 6c05f1ceb538..77e4f4e4c73c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -87,7 +87,7 @@ static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct 
tcp_md5sig_key *key,
                               __be32 daddr, __be32 saddr, const struct tcphdr 
*th);
 #endif
 
-struct inet_hashinfo tcp_hashinfo;
+struct inet_hashinfo tcp_hashinfo = { .protocol = IPPROTO_TCP };
 EXPORT_SYMBOL(tcp_hashinfo);
 
 static u32 tcp_v4_init_seq(const struct sk_buff *skb)
-- 
2.25.3