From 527beb8ef9c02c11f8ca0d59fc46f7d081db1c33 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 29 Oct 2020 15:04:57 +0800 Subject: [PATCH] udp: support sctp over udp in skb_udp_tunnel_segment For the gso of sctp over udp packets, sctp_gso_segment() will be called in skb_udp_tunnel_segment(), we need to set transport_header to sctp header. As all the current HWs can't handle both crc checksum and udp checksum at the same time, the crc checksum has to be done in sctp_gso_segment() by removing the NETIF_F_SCTP_CRC flag from the features. Meanwhile, if the HW can't do udp checksum, csum and csum_start has to be set correctly, and udp checksum will be done in __skb_udp_tunnel_segment() by calling gso_make_checksum(). Thanks to Paolo, Marcelo and Guillaume for helping with this one. v1->v2: - no change. v2->v3: - remove the he NETIF_F_SCTP_CRC flag from the features. - set csum and csum_start in sctp_gso_make_checksum(). Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski --- net/ipv4/udp_offload.c | 3 +++ net/sctp/offload.c | 6 +++++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index e67a66fbf27b..b8b1fdeb5af9 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -49,6 +49,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, __skb_pull(skb, tnl_hlen); skb_reset_mac_header(skb); skb_set_network_header(skb, skb_inner_network_offset(skb)); + skb_set_transport_header(skb, skb_inner_transport_offset(skb)); skb->mac_len = skb_inner_network_offset(skb); skb->protocol = new_protocol; @@ -67,6 +68,8 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM)))); features &= skb->dev->hw_enc_features; + /* CRC checksum can't be handled by HW when it's a UDP tunneling packet. */ + features &= ~NETIF_F_SCTP_CRC; /* The only checksum offload we care about from here on out is the * outer one so strip the existing checksum feature flags and diff --git a/net/sctp/offload.c b/net/sctp/offload.c index 74847d613835..ce281a9a2875 100644 --- a/net/sctp/offload.c +++ b/net/sctp/offload.c @@ -27,7 +27,11 @@ static __le32 sctp_gso_make_checksum(struct sk_buff *skb) { skb->ip_summed = CHECKSUM_NONE; skb->csum_not_inet = 0; - gso_reset_checksum(skb, ~0); + /* csum and csum_start in GSO CB may be needed to do the UDP + * checksum when it's a UDP tunneling packet. + */ + SKB_GSO_CB(skb)->csum = (__force __wsum)~0; + SKB_GSO_CB(skb)->csum_start = skb_headroom(skb) + skb->len; return sctp_compute_cksum(skb, skb_transport_offset(skb)); } -- 2.20.1