From 0bc919d3e0b8149a60d2444c6a8e2b5974556522 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Maciej=20=C5=BBenczykowski?= Date: Wed, 16 Jun 2021 17:09:52 -0700 Subject: [PATCH] bpf: Support all gso types in bpf_skb_change_proto() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Since we no longer modify gso_size, it is now theoretically safe to not set SKB_GSO_DODGY and reset gso_segs to zero. This also means the skb_is_gso_tcp() check should no longer be necessary. Unfortunately we cannot remove the skb_{decrease,increase}_gso_size() helpers, as they are still used elsewhere: bpf_skb_net_grow() without BPF_F_ADJ_ROOM_FIXED_GSO bpf_skb_net_shrink() without BPF_F_ADJ_ROOM_FIXED_GSO net/core/lwt_bpf.c's handle_gso_type() Signed-off-by: Maciej Żenczykowski Signed-off-by: Daniel Borkmann Cc: Dongseok Yi Cc: Willem de Bruijn Link: https://lore.kernel.org/bpf/20210617000953.2787453-3-zenczykowski@gmail.com --- net/core/filter.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index ae92a8bada0f..d062053994c7 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3241,9 +3241,6 @@ static int bpf_skb_proto_4_to_6(struct sk_buff *skb) u32 off = skb_mac_header_len(skb); int ret; - if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) - return -ENOTSUPP; - ret = skb_cow(skb, len_diff); if (unlikely(ret < 0)) return ret; @@ -3255,17 +3252,11 @@ static int bpf_skb_proto_4_to_6(struct sk_buff *skb) if (skb_is_gso(skb)) { struct skb_shared_info *shinfo = skb_shinfo(skb); - /* SKB_GSO_TCPV4 needs to be changed into - * SKB_GSO_TCPV6. - */ + /* SKB_GSO_TCPV4 needs to be changed into SKB_GSO_TCPV6. */ if (shinfo->gso_type & SKB_GSO_TCPV4) { shinfo->gso_type &= ~SKB_GSO_TCPV4; shinfo->gso_type |= SKB_GSO_TCPV6; } - - /* Header must be checked, and gso_segs recomputed. */ - shinfo->gso_type |= SKB_GSO_DODGY; - shinfo->gso_segs = 0; } skb->protocol = htons(ETH_P_IPV6); @@ -3280,9 +3271,6 @@ static int bpf_skb_proto_6_to_4(struct sk_buff *skb) u32 off = skb_mac_header_len(skb); int ret; - if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) - return -ENOTSUPP; - ret = skb_unclone(skb, GFP_ATOMIC); if (unlikely(ret < 0)) return ret; @@ -3294,17 +3282,11 @@ static int bpf_skb_proto_6_to_4(struct sk_buff *skb) if (skb_is_gso(skb)) { struct skb_shared_info *shinfo = skb_shinfo(skb); - /* SKB_GSO_TCPV6 needs to be changed into - * SKB_GSO_TCPV4. - */ + /* SKB_GSO_TCPV6 needs to be changed into SKB_GSO_TCPV4. */ if (shinfo->gso_type & SKB_GSO_TCPV6) { shinfo->gso_type &= ~SKB_GSO_TCPV6; shinfo->gso_type |= SKB_GSO_TCPV4; } - - /* Header must be checked, and gso_segs recomputed. */ - shinfo->gso_type |= SKB_GSO_DODGY; - shinfo->gso_segs = 0; } skb->protocol = htons(ETH_P_IP); -- 2.11.0