This is a note to let you know that I've just added the patch titled
tcp: gso: really support BIG TCP
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp-gso-really-support-big-tcp.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5a84117f2450a526fd3c2bcb954f2c82e3a8fdca
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Mon Jun 5 16:16:47 2023 +0000
tcp: gso: really support BIG TCP
[ Upstream commit 82a01ab35bd02ba4b0b4e12bc95c5b69240eb7b0 ]
We missed that tcp_gso_segment() was assuming skb->len was smaller than 65535 :
oldlen = (u16)~skb->len;
This part came with commit 0718bcc09b35 ("[NET]: Fix CHECKSUM_HW GSO problems.")
This leads to wrong TCP checksum.
Adapt the code to accept arbitrary packet length.
v2:
- use two csum_add() instead of csum_fold() (Alexander Duyck)
- Change delta type to __wsum to reduce casts (Alexander Duyck)
Fixes: 09f3d1a3a52c ("ipv6/gso: remove temporary HBH/jumbo header")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Alexander Duyck <alexanderduyck@xxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230605161647.3624428-1-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 45dda78893870..4851211aa60d6 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -60,12 +60,12 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
struct tcphdr *th;
unsigned int thlen;
unsigned int seq;
- __be32 delta;
unsigned int oldlen;
unsigned int mss;
struct sk_buff *gso_skb = skb;
__sum16 newcheck;
bool ooo_okay, copy_destructor;
+ __wsum delta;
th = tcp_hdr(skb);
thlen = th->doff * 4;
@@ -75,7 +75,7 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
if (!pskb_may_pull(skb, thlen))
goto out;
- oldlen = (u16)~skb->len;
+ oldlen = ~skb->len;
__skb_pull(skb, thlen);
mss = skb_shinfo(skb)->gso_size;
@@ -110,7 +110,7 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
if (skb_is_gso(segs))
mss *= skb_shinfo(segs)->gso_segs;
- delta = htonl(oldlen + (thlen + mss));
+ delta = (__force __wsum)htonl(oldlen + thlen + mss);
skb = segs;
th = tcp_hdr(skb);
@@ -119,8 +119,7 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);
- newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
- (__force u32)delta));
+ newcheck = ~csum_fold(csum_add(csum_unfold(th->check), delta));
while (skb->next) {
th->fin = th->psh = 0;
@@ -165,11 +164,11 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc));
}
- delta = htonl(oldlen + (skb_tail_pointer(skb) -
- skb_transport_header(skb)) +
- skb->data_len);
- th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
- (__force u32)delta));
+ delta = (__force __wsum)htonl(oldlen +
+ (skb_tail_pointer(skb) -
+ skb_transport_header(skb)) +
+ skb->data_len);
+ th->check = ~csum_fold(csum_add(csum_unfold(th->check), delta));
if (skb->ip_summed == CHECKSUM_PARTIAL)
gso_reset_checksum(skb, ~th->check);
else
