From 8d63bee643f1fb53e472f0e135cae4eb99d62d19 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Tue, 8 Aug 2017 14:22:55 -0400 Subject: [PATCH] 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 b2504a5dbef3 ("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: b2504a5dbef3 ("net: reduce skb_warn_bad_offload() noise") Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/core/dev.c | 2 +- net/ipv4/udp_offload.c | 2 +- net/ipv6/udp_offload.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 8515f8f..ce15a06 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2739,7 +2739,7 @@ static inline bool skb_needs_check(struct sk_buff *skb, bool tx_path) { if (tx_path) return skb->ip_summed != CHECKSUM_PARTIAL && - skb->ip_summed != CHECKSUM_NONE; + skb->ip_summed != CHECKSUM_UNNECESSARY; return skb->ip_summed == CHECKSUM_NONE; } diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 7812501..0932c85 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -235,7 +235,7 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, if (uh->check == 0) uh->check = CSUM_MANGLED_0; - skb->ip_summed = CHECKSUM_NONE; + skb->ip_summed = CHECKSUM_UNNECESSARY; /* If there is no outer header we can fake a checksum offload * due to the fact that we have already done the checksum in diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index a2267f80..e7d378c 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -72,7 +72,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, if (uh->check == 0) uh->check = CSUM_MANGLED_0; - skb->ip_summed = CHECKSUM_NONE; + skb->ip_summed = CHECKSUM_UNNECESSARY; /* If there is no outer header we can fake a checksum offload * due to the fact that we have already done the checksum in -- 2.7.4