From d5db21a3e6977dcb42cee3d16cd69901fa66510a Mon Sep 17 00:00:00 2001
From: William Tu <u9012063@gmail.com>
Date: Fri, 11 May 2018 05:49:47 -0700
Subject: [PATCH] erspan: auto detect truncated ipv6 packets.
Currently the truncated bit is set only when 1) the mirrored packet
is larger than mtu and 2) the ipv4 packet tot_len is larger than
the actual skb->len. This patch adds another case for detecting
whether ipv6 packet is truncated or not, by checking the ipv6 header
payload_len and the skb->len.
Reported-by: Xiaoyan Jin <xiaoyanj@vmware.com>
Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/ip_gre.c | 6 ++++++
net/ipv6/ip6_gre.c | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index dfe5b22f6ed4c..2409e648454df 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -579,6 +579,7 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
int version;
__be16 df;
int nhoff;
+ int thoff;
tun_info = skb_tunnel_info(skb);
if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
@@ -611,6 +612,11 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
(ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff))
truncate = true;
+ thoff = skb_transport_header(skb) - skb_mac_header(skb);
+ if (skb->protocol == htons(ETH_P_IPV6) &&
+ (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff))
+ truncate = true;
+
if (version == 1) {
erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)),
ntohl(md->u.index), truncate, true);
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index b511818b268c6..bede77f24784a 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -897,6 +897,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
int err = -EINVAL;
__u32 mtu;
int nhoff;
+ int thoff;
if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))
goto tx_err;
@@ -914,6 +915,11 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
(ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff))
truncate = true;
+ thoff = skb_transport_header(skb) - skb_mac_header(skb);
+ if (skb->protocol == htons(ETH_P_IPV6) &&
+ (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff))
+ truncate = true;
+
if (skb_cow_head(skb, dev->needed_headroom))
goto tx_err;
--
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