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authorJohannes Berg2022-02-02 10:49:36 +0200
committerJohannes Berg2022-02-04 16:23:19 +0100
commit667aa7426454154ec1e0922f92625bb33ae9951f (patch)
tree68356ae71ecf9a9e0c5d77df179b160d27c11f1b /net/mac80211
parentf39b7d62a19edd1fa391e9243bdc13cefca08b50 (diff)
cfg80211/mac80211: assume CHECKSUM_COMPLETE includes SNAP
There's currently only one driver that reports CHECKSUM_COMPLETE, that is iwlwifi. The current hardware there calculates checksum after the SNAP header, but only RFC 1042 (and some other cases, but replicating the exact hardware logic for corner cases in the driver seemed awkward.) Newer generations of hardware will checksum _including_ the SNAP, which makes things easier. To handle that, simply always assume the checksum _includes_ the SNAP header, which this patch does, requiring to first add it for older iwlwifi hardware, and then remove it again later on conversion. Alternatively, we could have: 1) Always assumed the checksum starts _after_ the SNAP header; the problem with this is that we'd have to replace the exact "what is the SNAP" check in iwlwifi that cfg80211 has. 2) Made it configurable with some flag, but that seemed like too much complexity. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Luca Coelho <luciano.coelho@intel.com> Link: https://lore.kernel.org/r/iwlwifi.20220202104617.230736e19e0e.I3e6745873585ad943c152fab9e23b5221f17a95f@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211')
-rw-r--r--net/mac80211/rx.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 93680af62c47..d54a4d98c648 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -4629,6 +4629,8 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx,
/* do the header conversion - first grab the addresses */
ether_addr_copy(addrs.da, skb->data + fast_rx->da_offs);
ether_addr_copy(addrs.sa, skb->data + fast_rx->sa_offs);
+ skb_postpull_rcsum(skb, skb->data + snap_offs,
+ sizeof(rfc1042_header) + 2);
/* remove the SNAP but leave the ethertype */
skb_pull(skb, snap_offs + sizeof(rfc1042_header));
/* push the addresses in front */