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Code Issues Releases Wiki Activity

bpf: Support all gso types in bpf_skb_change_proto() 

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 <maze@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dongseok Yi <dseok.yi@samsung.com>
Cc: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/bpf/20210617000953.2787453-3-zenczykowski@gmail.com
This commit is contained in:
Maciej Żenczykowski 2021-06-16 17:09:52 -07:00 committed by Daniel Borkmann
parent 364745fbe9
commit 0bc919d3e0
1 changed files with 2 additions and 20 deletions
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22
net/core/filter.c
View File

@ -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);