linux/net/ipv6/udp_offload.c
Willem de Bruijn 8d63bee643 net: avoid skb_warn_bad_offload false positives on UFO
skb_warn_bad_offload triggers a warning when an skb enters the GSO
stack at __skb_gso_segment that does not have CHECKSUM_PARTIAL
checksum offload set.

Commit b2504a5dbe ("net: reduce skb_warn_bad_offload() noise")
observed that SKB_GSO_DODGY producers can trigger the check and
that passing those packets through the GSO handlers will fix it
up. But, the software UFO handler will set ip_summed to
CHECKSUM_NONE.

When __skb_gso_segment is called from the receive path, this
triggers the warning again.

Make UFO set CHECKSUM_UNNECESSARY instead of CHECKSUM_NONE. On
Tx these two are equivalent. On Rx, this better matches the
skb state (checksum computed), as CHECKSUM_NONE here means no
checksum computed.

See also this thread for context:
http://patchwork.ozlabs.org/patch/799015/

Fixes: b2504a5dbe ("net: reduce skb_warn_bad_offload() noise")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-08 21:39:01 -07:00

93 lines
2.3 KiB
C

/*
* IPV6 GSO/GRO offload support
* Linux INET6 implementation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* UDPv6 GSO support
*/
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <net/protocol.h>
#include <net/ipv6.h>
#include <net/udp.h>
#include <net/ip6_checksum.h>
#include "ip6_offload.h"
static struct sk_buff *udp6_tunnel_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
if (skb->encapsulation && skb_shinfo(skb)->gso_type &
(SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
segs = skb_udp_tunnel_segment(skb, features, true);
return segs;
}
static struct sk_buff **udp6_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
struct udphdr *uh = udp_gro_udphdr(skb);
if (unlikely(!uh))
goto flush;
/* Don't bother verifying checksum if we're going to flush anyway. */
if (NAPI_GRO_CB(skb)->flush)
goto skip;
if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
ip6_gro_compute_pseudo))
goto flush;
else if (uh->check)
skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
ip6_gro_compute_pseudo);
skip:
NAPI_GRO_CB(skb)->is_ipv6 = 1;
return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
flush:
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
{
const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
if (uh->check) {
skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
&ipv6h->daddr, 0);
} else {
skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
}
return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
}
static const struct net_offload udpv6_offload = {
.callbacks = {
.gso_segment = udp6_tunnel_segment,
.gro_receive = udp6_gro_receive,
.gro_complete = udp6_gro_complete,
},
};
int udpv6_offload_init(void)
{
return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
}
int udpv6_offload_exit(void)
{
return inet6_del_offload(&udpv6_offload, IPPROTO_UDP);
}