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Date: Fri, 15 Jan 2021 22:20:35 +0900
From: Dongseok Yi <dseok.yi@...sung.com>
To: "David S. Miller" <davem@...emloft.net>,
Steffen Klassert <steffen.klassert@...unet.com>,
Alexander Lobakin <alobakin@...me>
Cc: namkyu78.kim@...sung.com, Dongseok Yi <dseok.yi@...sung.com>,
Jakub Kicinski <kuba@...nel.org>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Willem de Bruijn <willemb@...gle.com>,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net v2] udp: ipv4: manipulate network header of NATed UDP
GRO fraglist
UDP/IP header of UDP GROed frag_skbs are not updated even after NAT
forwarding. Only the header of head_skb from ip_finish_output_gso ->
skb_gso_segment is updated but following frag_skbs are not updated.
A call path skb_mac_gso_segment -> inet_gso_segment ->
udp4_ufo_fragment -> __udp_gso_segment -> __udp_gso_segment_list
does not try to update UDP/IP header of the segment list but copy
only the MAC header.
Update dport, daddr and checksums of each skb of the segment list
in __udp_gso_segment_list. It covers both SNAT and DNAT.
Fixes: 9fd1ff5d2ac7 (udp: Support UDP fraglist GRO/GSO.)
Signed-off-by: Dongseok Yi <dseok.yi@...sung.com>
---
v1:
Steffen Klassert said, there could be 2 options.
https://lore.kernel.org/patchwork/patch/1362257/
I was trying to write a quick fix, but it was not easy to forward
segmented list. Currently, assuming DNAT only.
v2:
Per Steffen Klassert request, move the procedure from
udp4_ufo_fragment to __udp_gso_segment_list and support SNAT.
To Alexander Lobakin, I've checked your email late. Just use this
patch as a reference. It support SNAT too, but does not support IPv6
yet. I cannot make IPv6 header changes in __udp_gso_segment_list due
to the file is in IPv4 directory.
include/net/udp.h | 2 +-
net/ipv4/udp_offload.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++----
net/ipv6/udp_offload.c | 2 +-
3 files changed, 59 insertions(+), 7 deletions(-)
diff --git a/include/net/udp.h b/include/net/udp.h
index 877832b..01351ba 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -178,7 +178,7 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
- netdev_features_t features);
+ netdev_features_t features, bool is_ipv6);
static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
{
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index ff39e94..c532d3b 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -187,8 +187,57 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
}
EXPORT_SYMBOL(skb_udp_tunnel_segment);
+static void __udpv4_gso_segment_csum(struct sk_buff *seg,
+ __be32 *oldip, __be32 *newip,
+ __be16 *oldport, __be16 *newport)
+{
+ struct udphdr *uh = udp_hdr(seg);
+ struct iphdr *iph = ip_hdr(seg);
+
+ if (uh->check) {
+ inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
+ true);
+ inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
+ false);
+ if (!uh->check)
+ uh->check = CSUM_MANGLED_0;
+ }
+ uh->dest = *newport;
+
+ csum_replace4(&iph->check, *oldip, *newip);
+ iph->daddr = *newip;
+}
+
+static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
+{
+ struct sk_buff *seg;
+ struct udphdr *uh, *uh2;
+ struct iphdr *iph, *iph2;
+
+ seg = segs;
+ uh = udp_hdr(seg);
+ iph = ip_hdr(seg);
+
+ while ((seg = seg->next)) {
+ uh2 = udp_hdr(seg);
+ iph2 = ip_hdr(seg);
+
+ if (uh->source != uh2->source || iph->saddr != iph2->saddr)
+ __udpv4_gso_segment_csum(seg,
+ &iph2->saddr, &iph->saddr,
+ &uh2->source, &uh->source);
+
+ if (uh->dest != uh2->dest || iph->daddr != iph2->daddr)
+ __udpv4_gso_segment_csum(seg,
+ &iph2->daddr, &iph->daddr,
+ &uh2->dest, &uh->dest);
+ }
+
+ return segs;
+}
+
static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
- netdev_features_t features)
+ netdev_features_t features, bool is_ipv6)
{
unsigned int mss = skb_shinfo(skb)->gso_size;
@@ -198,11 +247,14 @@ static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
- return skb;
+ if (is_ipv6)
+ return skb;
+ else
+ return __udpv4_gso_segment_list_csum(skb);
}
struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
- netdev_features_t features)
+ netdev_features_t features, bool is_ipv6)
{
struct sock *sk = gso_skb->sk;
unsigned int sum_truesize = 0;
@@ -214,7 +266,7 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
__be16 newlen;
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
- return __udp_gso_segment_list(gso_skb, features);
+ return __udp_gso_segment_list(gso_skb, features, is_ipv6);
mss = skb_shinfo(gso_skb)->gso_size;
if (gso_skb->len <= sizeof(*uh) + mss)
@@ -328,7 +380,7 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
goto out;
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
- return __udp_gso_segment(skb, features);
+ return __udp_gso_segment(skb, features, false);
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index c7bd7b1..faa823c 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -42,7 +42,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
goto out;
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
- return __udp_gso_segment(skb, features);
+ return __udp_gso_segment(skb, features, true);
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
--
2.7.4
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