path: root/net/ipv6/sit.c
diff options
authorEric Dumazet <edumazet@google.com>2016-06-18 21:52:06 -0700
committerDavid S. Miller <davem@davemloft.net>2016-06-18 22:11:39 -0700
commit20e1954fe238dbe5f8d3a979e593fe352bd703cf (patch)
tree22aced0e24480c8f2c62b89934868e64bbc70baa /net/ipv6/sit.c
parentgre: better support for ICMP messages for gre+ipv6 (diff)
ipv6: RFC 4884 partial support for SIT/GRE tunnels
When receiving an ICMPv4 message containing extensions as defined in RFC 4884, and translating it to ICMPv6 at SIT or GRE tunnel, we need some extra manipulation in order to properly forward the extensions. This patch only takes care of Time Exceeded messages as they are the ones that typically carry information from various routers in a fabric during a traceroute session. It also avoids complex skb logic if the data_len is not a multiple of 8. RFC states : The "original datagram" field MUST contain at least 128 octets. If the original datagram did not contain 128 octets, the "original datagram" field MUST be zero padded to 128 octets. In practice routers use 128 bytes of original datagram, not more. Initial translation was added in commit ca15a078bd90 ("sit: generate icmpv6 error when receiving icmpv4 error") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Oussama Ghorbel <ghorbel@pivasoftware.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/sit.c')
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index d7a36114eb50..cdd714690f95 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -484,6 +484,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
const struct iphdr *iph = (const struct iphdr *)skb->data;
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
+ unsigned int data_len = 0;
struct ip_tunnel *t;
int err;
@@ -508,6 +509,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
if (code != ICMP_EXC_TTL)
return 0;
+ data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
@@ -536,7 +538,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
err = 0;
- if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type))
+ if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
goto out;
if (t->parms.iph.daddr == 0)