[PATCH net-next v2 07/12] udp: Support BIG TCP GSO packets where they can occur

[Alice Mikityanska <alice.kernel@fastmail.im>]

From: Alice Mikityanska <alice@isovalent.com>

Wherever a GSO packet can occur, and its length is used to fill the UDP
header, use udp_set_len that assigns 0 if the length doesn't fit 16
bits, so that the packet can be properly parsed and segmented later,
instead of having truncated length.

Signed-off-by: Alice Mikityanska <alice@isovalent.com>
---
 net/ipv4/fou_core.c                    | 2 +-
 net/ipv6/fou6.c                        | 2 +-
 net/netfilter/ipvs/ip_vs_xmit.c        | 2 +-
 net/netfilter/nf_conntrack_proto_udp.c | 4 +++-
 net/netfilter/nf_nat_helper.c          | 2 +-
 net/psp/psp_main.c                     | 2 +-
 6 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/fou_core.c b/net/ipv4/fou_core.c
index 7aeb6efbfc44..d934860e1f34 100644
--- a/net/ipv4/fou_core.c
+++ b/net/ipv4/fou_core.c
@@ -1043,7 +1043,7 @@ static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
 
 	uh->dest = e->dport;
 	uh->source = sport;
-	udp_set_len_short(uh, skb->len);
+	udp_set_len(uh, skb->len);
 	udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
 		     fl4->saddr, fl4->daddr, skb->len);
 
diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c
index abcf23500299..3c79fe8aba1b 100644
--- a/net/ipv6/fou6.c
+++ b/net/ipv6/fou6.c
@@ -30,7 +30,7 @@ static void fou6_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
 
 	uh->dest = e->dport;
 	uh->source = sport;
-	udp_set_len_short(uh, skb->len);
+	udp_set_len(uh, skb->len);
 	udp6_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM6), skb,
 		      &fl6->saddr, &fl6->daddr, skb->len);
 
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index b460998e348e..08b0b5bfe4ec 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -1089,7 +1089,7 @@ ipvs_gue_encap(struct net *net, struct sk_buff *skb,
 	dport = cp->dest->tun_port;
 	udph->dest = dport;
 	udph->source = sport;
-	udp_set_len_short(udph, skb->len);
+	udp_set_len(udph, skb->len);
 	udph->check = 0;
 
 	*next_protocol = IPPROTO_UDP;
diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c
index e9bd1632304f..ca7d259ded8b 100644
--- a/net/netfilter/nf_conntrack_proto_udp.c
+++ b/net/netfilter/nf_conntrack_proto_udp.c
@@ -45,9 +45,11 @@ static bool udp_validate_len(struct sk_buff *skb,
 			     const struct udphdr *hdr,
 			     unsigned int dataoff)
 {
-	unsigned int udplen = udp_get_len_short(hdr);
+	unsigned int udplen = ntohs(hdr->len);
 	unsigned int skblen = skb->len - dataoff;
 
+	if (!udplen && skblen >= GRO_LEGACY_MAX_SIZE)
+		return true;
 	if (udplen > skblen || udplen < sizeof(*hdr))
 		return false;
 	return true;
diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c
index 3853f41db499..ec34a2f4baa8 100644
--- a/net/netfilter/nf_nat_helper.c
+++ b/net/netfilter/nf_nat_helper.c
@@ -161,7 +161,7 @@ nf_nat_mangle_udp_packet(struct sk_buff *skb,
 
 	/* update the length of the UDP packet */
 	datalen = skb->len - protoff;
-	udp_set_len_short(udph, datalen);
+	udp_set_len(udph, datalen);
 
 	/* fix udp checksum if udp checksum was previously calculated */
 	if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
diff --git a/net/psp/psp_main.c b/net/psp/psp_main.c
index 2415b75a2a12..c9c60cb69daa 100644
--- a/net/psp/psp_main.c
+++ b/net/psp/psp_main.c
@@ -207,7 +207,7 @@ static void psp_write_headers(struct net *net, struct sk_buff *skb, __be32 spi,
 		uh->source = udp_flow_src_port(net, skb, 0, 0, false);
 	}
 	uh->check = 0;
-	udp_set_len_short(uh, udp_len);
+	udp_set_len(uh, udp_len);
 
 	psph->nexthdr = IPPROTO_TCP;
 	psph->hdrlen = PSP_HDRLEN_NOOPT;
-- 
2.52.0